MedWorm.com provides a medical RSS filtering service. Over 6000 RSS medical sources are combined and output via different filters. This feed contains the latest items from the 'Annual Review of Microbiology' source. Sun, 11 Dec 2011 11:38:27 +0100 http://www.medworm.com/index.php?rid=5275477&cid=s_37530_77_f&fid=37530&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21639788%26dopt%3DAbstract Authors: Merdanovic M, Clausen T, Kaiser M, Huber R, Ehrmann M Abstract Protein quality control involves sensing and treatment of defective or incomplete protein structures. Misfolded or mislocalized proteins trigger dedicated signal transduction cascades that upregulate the production of protein quality-control factors. Corresponding proteases and chaperones either degrade or repair damaged proteins, thereby reducing the level of aggregation-prone molecules. Because the periplasm of gram-negative bacteria is particularly exposed to environmental changes and respective protein-folding stresses connected with the presence of detergents, low or high osmolarity of the medium, elevated temperatures, and the host's immune response, fine-tuned protein quality control systems are essentia... Annual Review of Microbiology journals http://www.medworm.com/rss/comments.php?id=5275477 Mon, 03 Oct 2011 11:55:35 +0100 5275477 http://www.medworm.com/index.php?rid=5275476&cid=s_37530_77_f&fid=37530&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21663441%26dopt%3DAbstract Authors: Henry JT, Crosson S Abstract Per-Arnt-Sim (PAS) domains occur in proteins from all kingdoms of life. In the bacterial kingdom, PAS domains are commonly positioned at the amino terminus of signaling proteins such as sensor histidine kinases, cyclic-di-GMP synthases/hydrolases, and methyl-accepting chemotaxis proteins. Although these domains are highly divergent at the primary sequence level, the structures of dozens of PAS domains across a broad section of sequence space have been solved, revealing a conserved three-dimensional architecture. An all-versus-all alignment of 63 PAS structures demonstrates that the PAS domain family forms structural clades on the basis of two principal variables: (a) topological location inside or outside the plasma membrane and (b) the class o... Annual Review of Microbiology journals http://www.medworm.com/rss/comments.php?id=5275476 Mon, 03 Oct 2011 11:55:25 +0100 5275476 http://www.medworm.com/index.php?rid=5275475&cid=s_37530_77_f&fid=37530&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21740227%26dopt%3DAbstract Authors: Fuchs G Abstract The fixation of inorganic carbon into organic material (autotrophy) is a prerequisite for life and sets the starting point of biological evolution. In the extant biosphere the reductive pentose phosphate (Calvin-Benson) cycle is the predominant mechanism by which many prokaryotes and all plants fix CO(2) into biomass. However, the fact that five alternative autotrophic pathways exist in prokaryotes is often neglected. This bias may lead to serious misjudgments in models of the global carbon cycle, in hypotheses on the evolution of metabolism, and in interpretations of geological records. Here, I review these alternative pathways that differ fundamentally from the Calvin-Benson cycle. Revealingly, these five alternative pathways pivot on acetyl-coenzyme A, ... Annual Review of Microbiology journals http://www.medworm.com/rss/comments.php?id=5275475 Mon, 03 Oct 2011 11:55:15 +0100 5275475 http://www.medworm.com/index.php?rid=5259429&cid=s_37530_77_f&fid=37530&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21939377%26dopt%3DAbstract Authors: Lertsethtakarn P, Ottemann KM, Hendrixson DR Abstract Flagellar motility of Campylobacter jejuni and Helicobacter pylori influences host colonization by promoting migration through viscous milieus such as gastrointestinal mucus. This review explores mechanisms C. jejuni and H. pylori employ to control flagellar biosynthesis and chemotactic responses. These microbes tightly control the activities of ?(54) and ?(28) to mediate ordered flagellar gene expression. In addition to phase-variable and posttranslational mechanisms, flagellar biosynthesis is regulated spatially and numerically so that only a certain number of organelles are placed at polar sites. To mediate chemotaxis, C. jejuni and H. pylori combine basic chemotaxis signal transduction components with several access... Annual Review of Microbiology journals http://www.medworm.com/rss/comments.php?id=5259429 Wed, 28 Sep 2011 10:10:34 +0100 5259429 http://www.medworm.com/index.php?rid=5259428&cid=s_37530_77_f&fid=37530&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21939378%26dopt%3DAbstract Authors: Atluri VL, Xavier MN, de Jong MF, den Hartigh AB, Tsolis RE Abstract Brucellosis is a zoonotic infection caused primarily by the bacterial pathogens Brucella melitensis and B. abortus. It is acquired by consumption of unpasteurized dairy products or by contact with infected animals. Globally, it is one of the most widespread zoonoses, with 500,000 new cases reported each year. In endemic areas, Brucella infections represent a serious public health problem that results in significant morbidity and economic losses. An important feature of the disease is persistent bacterial colonization of the reticuloendothelial system. In this review we discuss recent insights into mechanisms of intracellular survival and immune evasion that contribute to systemic persistence by the pathog... Annual Review of Microbiology journals http://www.medworm.com/rss/comments.php?id=5259428 Wed, 28 Sep 2011 10:10:24 +0100 5259428 http://www.medworm.com/index.php?rid=4953673&cid=s_37530_77_f&fid=37530&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21682647%26dopt%3DAbstract Authors: Piel J Bacteria are one of the most important sources of bioactive natural products for drug discovery. Yet, in most habitats only a small percentage of all existing prokaryotes is amenable to cultivation and chemical study. There is strong evidence that the uncultivated diversity represents an enormous resource of novel biosynthetic enzymes and secondary metabolites. In addition, many animal-derived drug candidates that are structurally characterized but difficult to access seem to be produced by uncultivated, symbiotic bacteria. This review provides an overview about established and emerging techniques for the investigation and exploitation of the environmental metabolome. These include metagenomic library construction and screening, heterologous expression, community sequen... Annual Review of Microbiology journals http://www.medworm.com/rss/comments.php?id=4953673 Wed, 15 Jun 2011 23:00:00 +0100 4953673 http://www.medworm.com/index.php?rid=4905455&cid=s_37530_77_f&fid=37530&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21639792%26dopt%3DAbstract Authors: Fournier PE, Raoult D The availability of genome sequences has revolutionized the fields of microbiology and infectious diseases. Indeed, more than 1,000 bacterial genomes and 3,000 viral genomes, including representatives of all significant human pathogens, have been sequenced to date. Owing to this tremendous amount of data, genomes are regarded as chimeras of sequence fragments from various origins. Coupled with novel proteomic analyses, genome sequencing has also resulted in unprecedented advances in pathogen diagnosis and genotyping and in the detection of virulence and antibiotic resistance. Herein, we review current achievements of genomics and proteomics and discuss potential developments for clinical microbiology laboratories. Expected final online publication date fo... Annual Review of Microbiology journals http://www.medworm.com/rss/comments.php?id=4905455 Thu, 02 Jun 2011 23:00:00 +0100 4905455 http://www.medworm.com/index.php?rid=4905445&cid=s_37530_77_f&fid=37530&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21639793%26dopt%3DAbstract Authors: Battesti A, Majdalani N, Gottesman S Under conditions of nutrient deprivation or stress, or as cells enter stationary phase, Escherichia coli and related bacteria increase the accumulation of RpoS, a specialized sigma factor. RpoS-dependent gene expression leads to general stress resistance of cells. During rapid growth, RpoS translation is inhibited and any RpoS protein that is synthesized is rapidly degraded. The complex transition from exponential growth to stationary phase has been partially dissected by analyzing the induction of RpoS after specific stress treatments. Different stress conditions lead to induction of specific sRNAs that stimulate RpoS translation or to induction of small-protein antiadaptors that stabilize the protein. Recent progress has led to a better, ... Annual Review of Microbiology journals http://www.medworm.com/rss/comments.php?id=4905445 Thu, 02 Jun 2011 23:00:00 +0100 4905445 http://www.medworm.com/index.php?rid=4905472&cid=s_37530_77_f&fid=37530&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21639791%26dopt%3DAbstract Authors: Hammer ND, Skaar EP The unique redox potential of iron is an ideal cofactor in diverse biochemical reactions. Iron is therefore vital for the growth and proliferation of nearly all organisms, including pathogenic bacteria. Vertebrates sequester excess iron within proteins in order to alleviate toxicity and restrict the amount of free iron available for invading pathogens. Restricting the growth of infectious microorganisms by sequestering essential nutrients is referred to as nutritional immunity. In order to circumvent nutritional immunity, bacterial pathogens have evolved elegant systems that allow for the acquisition of iron during infection. The gram-positive extracellular pathogen Staphylococcus aureus is a commensal organism that can cause severe disease when it gains ac... Annual Review of Microbiology journals http://www.medworm.com/rss/comments.php?id=4905472 Wed, 01 Jun 2011 23:00:00 +0100 4905472 http://www.medworm.com/index.php?rid=4905500&cid=s_37530_77_f&fid=37530&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21639790%26dopt%3DAbstract Authors: Leonard AC, Grimwade JE To ensure proper timing of chromosome duplication during the cell cycle, bacteria must carefully regulate the activity of initiator protein, DnaA, and its interactions with the unique replication origin, oriC. Although several protein regulators of DnaA are known, recent evidence suggests that DnaA recognition sites, in multiple genomic locations, also play an important role in controlling assembly of pre-replicative complexes. In oriC, closely spaced high- and low-affinity recognition sites direct DnaA-DnaA interactions and couple complex assembly to the availability of active DnaA-ATP. Additional recognition sites at loci distant from oriC modulate DnaA-ATP availability by repressing new synthesis, recharging inactive DnaA-ADP, or titrating DnaA. Rely... Annual Review of Microbiology journals http://www.medworm.com/rss/comments.php?id=4905500 Mon, 30 May 2011 23:00:00 +0100 4905500 http://www.medworm.com/index.php?rid=3955211&cid=s_37530_77_f&fid=37530&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20825344%26dopt%3DAbstract Authors: Otto M Community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) strains are causing a severe pandemic of mainly skin and soft tissue and occasionally fatal infections. The basis of their success is the combination of methicillin resistance at low fitness cost and high virulence. Investigation of the virulence potential of CA-MRSA, a key prerequisite for the development of anti-CA-MRSA therapeutics, has focused on strain USA300, which is responsible for the most serious CA-MRSA epidemic seen in the United States. Current data indicate that in this strain virulence evolved via increased expression of core-genome-encoded virulence determinants, such as alpha-toxin and phenol-soluble modulins, and acquisition of the phage-encoded Panton-Valentine leukocidin (PVL)... Annual Review of Microbiology journals http://www.medworm.com/rss/comments.php?id=3955211 Fri, 10 Sep 2010 22:33:46 +0100 3955211 http://www.medworm.com/index.php?rid=3955210&cid=s_37530_77_f&fid=37530&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20825345%26dopt%3DAbstract Authors: Kulp A, Kuehn MJ Gram-negative bacteria produce outer membrane vesicles (OMVs) that contain biologically active proteins and perform diverse biological processes. Unlike other secretion mechanisms, OMVs enable bacteria to secrete insoluble molecules in addition to and in complex with soluble material. OMVs allow enzymes to reach distant targets in a concentrated, protected, and targeted form. OMVs also play roles in bacterial survival: Their production is a bacterial stress response and important for nutrient acquisition, biofilm development, and pathogenesis. Key characteristics of OMV biogenesis include outward bulging of areas lacking membrane-peptidoglycan bonds, the capacity to upregulate vesicle production without also losing outer membrane integrity, enrichment or exclu... Annual Review of Microbiology journals http://www.medworm.com/rss/comments.php?id=3955210 Fri, 10 Sep 2010 22:33:43 +0100 3955210 http://www.medworm.com/index.php?rid=3955209&cid=s_37530_77_f&fid=37530&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20825346%26dopt%3DAbstract Authors: Hunstad DA, Justice SS Paradigms in the pathogenesis of urinary tract infections have shifted dramatically as a result of recent scientific revelations. Beyond extracellular colonization of the bladder luminal surface, as traditional clinical thinking would hold, uropathogenic bacteria direct a complex, intracellular cascade that shelters bacteria from host defenses and leads to persistent bacterial residence within the epithelium. After epithelial invasion, many organisms are promptly expelled by bladder epithelial cells; a minority establish a niche in the cytoplasm that results in the development of biofilm-like intracellular bacterial communities and serves as the primary location for bacterial expansion. Exfoliation of the superficial epithelial layer acts to reduce the b... Annual Review of Microbiology journals http://www.medworm.com/rss/comments.php?id=3955209 Fri, 10 Sep 2010 22:33:38 +0100 3955209 http://www.medworm.com/index.php?rid=3955208&cid=s_37530_77_f&fid=37530&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20825347%26dopt%3DAbstract Authors: Young KD Events in the past decade have made it both possible and interesting to ask how bacteria create cells of defined length, diameter, and morphology. The current consensus is that bacterial shape is determined by the coordinated activities of cytoskeleton complexes that drive cell elongation and division. Cell length is most easily explained by the timing of cell division, principally by regulating the activity of the FtsZ protein. However, the question of how cells establish and maintain a specific and uniform diameter is, by far, much more difficult to answer. Mutations associated with the elongation complex often alter cell width, though it is not clear how. Some evidence suggests that diameter is strongly influenced by events during cell division. In addition, surpri... Annual Review of Microbiology journals http://www.medworm.com/rss/comments.php?id=3955208 Fri, 10 Sep 2010 22:33:34 +0100 3955208 http://www.medworm.com/index.php?rid=3955207&cid=s_37530_77_f&fid=37530&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20825348%26dopt%3DAbstract Authors: den Boon JA, Ahlquist P Positive-strand RNA virus genome replication is invariably associated with extensively rearranged intracellular membranes. Recent biochemical and electron microscopy analyses, including three-dimensional electron microscope tomographic imaging, have fundamentally advanced our understanding of the ultrastructure and function of organelle-like RNA replication factories. Notably, for a range of positive-strand RNA viruses embodying many major differences, independent studies have revealed multiple common principles. These principles include that RNA replication often occurs inside numerous virus-induced vesicles invaginated or otherwise elaborated from a continuous, often endoplasmic reticulum-derived membrane network. Where analyzed, each such vesicle typ... Annual Review of Microbiology journals http://www.medworm.com/rss/comments.php?id=3955207 Fri, 10 Sep 2010 22:33:29 +0100 3955207 http://www.medworm.com/index.php?rid=3955206&cid=s_37530_77_f&fid=37530&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20825349%26dopt%3DAbstract Authors: Silva-Rocha R, de Lorenzo V Robustness is the quality of any relational object (biological or otherwise) to maintain its components, its structure, and its function despite both external changes and endogenous fluctuations. Live systems are surprisingly robust, as they are able to not only preserve their physi-cochemical architecture in the face of variable nutritional and environmental conditions, but also tolerate stochastic variability in the concentrations of their components, fix errors resulting from hazardous events, and make virtually perfect copies of themselves. These qualities have started to be comprehended in full only since the application of network theory formalisms to regulatory phenomena. This review addresses the distinct role of network architecture (topolo... Annual Review of Microbiology journals http://www.medworm.com/rss/comments.php?id=3955206 Fri, 10 Sep 2010 22:33:25 +0100 3955206 http://www.medworm.com/index.php?rid=3955205&cid=s_37530_77_f&fid=37530&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20825350%26dopt%3DAbstract Authors: Eisenstark A Extensive phenotypic and genomic diversity was detected among offspring of Salmonella enterica ssp. enterica serovar Typhimurium LT2 (nonmutator) and LT7 (mutator, mutL) strains after decades of storage in sealed nutrient agar stabs. In addition to numerous losses in carbon and nitrogen metabolism, the acquired new metabolites indicated that alternate pathways were established. Particularly striking was the array of phage types when this phenotype was expected to be a stable feature. Evidence is presented regarding the role of mutator gene mutL(-) in the establishment of diversity as well as the ability of cells to return to mutL(+) genetic stabilization. Mutations included deletions, duplications, frameshifts, inversions and transpositions. In competition tests, ... Annual Review of Microbiology journals http://www.medworm.com/rss/comments.php?id=3955205 Fri, 10 Sep 2010 22:33:22 +0100 3955205 http://www.medworm.com/index.php?rid=3955204&cid=s_37530_77_f&fid=37530&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20825351%26dopt%3DAbstract Authors: Chao MC, Rubin EJ Mycobacterium tuberculosis, which causes tuberculosis, remains a major human public health threat. This is largely due to a sizeable reservoir of latently infected individuals, who may relapse into active disease decades after first acquiring the infection. Furthermore, patients have a very slow response to treatment of active disease. Latency and antibiotic tolerance are commonly taken as a proxy for dormancy, a stable nonreplicative state. However, latency is a clinical term that is solely defined by a lack of disease indicators. The actual state of the bacterium in human latency is not well understood. Here we evaluate the results of several in vitro models of dormancy and consider the applicability of various animal models for studying aspects of human la... Annual Review of Microbiology journals http://www.medworm.com/rss/comments.php?id=3955204 Fri, 10 Sep 2010 22:33:18 +0100 3955204 http://www.medworm.com/index.php?rid=3955203&cid=s_37530_77_f&fid=37530&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20825352%26dopt%3DAbstract Authors: Kung C, Martinac B, Sukharev S All cells, including microbes, detect and respond to mechanical forces, of which osmotic pressure is most ancient and universal. Channel proteins have evolved such that they can be directly stretched open when the membrane is under turgor pressure. Osmotic downshock, as in rain, opens bacterial mechanosensitive (MS) channels to jettison osmolytes, relieving pressure and preventing cell lysis. The ion flux through individual channel proteins can be observed directly with a patch clamp. MS channels of large and small conductance (MscL and MscS, respectively) have been cloned, crystallized, and subjected to biophysical and genetic analyses in depth. They are now models to scrutinize how membrane forces direct protein conformational changes. Eukaryot... Annual Review of Microbiology journals http://www.medworm.com/rss/comments.php?id=3955203 Fri, 10 Sep 2010 22:33:14 +0100 3955203 http://www.medworm.com/index.php?rid=3955202&cid=s_37530_77_f&fid=37530&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20825353%26dopt%3DAbstract Authors: Kerfeld CA, Heinhorst S, Cannon GC Bacterial microcompartments (BMCs) are organelles composed entirely of protein. They promote specific metabolic processes by encapsulating and colocalizing enzymes with their substrates and cofactors, by protecting vulnerable enzymes in a defined microenvironment, and by sequestering toxic or volatile intermediates. Prototypes of the BMCs are the carboxysomes of autotrophic bacteria. However, structures of similar polyhedral shape are being discovered in an ever-increasing number of heterotrophic bacteria, where they participate in the utilization of specialty carbon and energy sources. Comparative genomics reveals that the potential for this type of compartmentalization is widespread across bacterial phyla and suggests that genetic modules e... Annual Review of Microbiology journals http://www.medworm.com/rss/comments.php?id=3955202 Fri, 10 Sep 2010 22:33:11 +0100 3955202 http://www.medworm.com/index.php?rid=3955201&cid=s_37530_77_f&fid=37530&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20825354%26dopt%3DAbstract Authors: Krell T, Lacal J, Busch A, Silva-Jiménez H, Guazzaroni ME, Ramos JL Bacteria sense and respond to a wide range of physical and chemical signals. Central to sensing and responding to these signals are two-component systems, which have a sensor histidine kinase (SK) and a response regulator (RR) as basic components. Here we review the different molecular mechanisms by which these signals are integrated and modulate the phosphorylation state of SKs. Apart from the basic mechanism, which consists of signal recognition by the SK that leads to an alteration of its autokinase activity and subsequently a change in the RR phosphorylation state, a variety of alternative modes have evolved. The biochemical data available on SKs, particularly their molecular interactions with signals, ... Annual Review of Microbiology journals http://www.medworm.com/rss/comments.php?id=3955201 Fri, 10 Sep 2010 22:33:07 +0100 3955201 http://www.medworm.com/index.php?rid=3691707&cid=s_37530_77_f&fid=37530&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20565252%26dopt%3DAbstract Authors: Emerson D, Fleming EJ, McBeth JM In the 1830s, iron bacteria were among the first groups of microbes to be recognized for carrying out a fundamental geological process, namely the oxidation of iron. Due to lingering questions about their metabolism, coupled with difficulties in culturing important community members, studies of Fe-oxidizing bacteria (FeOB) have lagged behind other important microbial lithotrophic metabolisms. Recently, research on lithotrophic, oxygen-dependent FeOB that grow at circumneutral pH has accelerated. This work is driven by several factors including the recognition by both microbiologists and geoscientists of the role FeOB play in the biogeochemistry of iron and other elements. The isolation of new strains of obligate FeOB allowed a better understand... Annual Review of Microbiology journals http://www.medworm.com/rss/comments.php?id=3691707 Sun, 20 Jun 2010 23:00:00 +0100 3691707 http://www.medworm.com/index.php?rid=3655848&cid=s_37530_77_f&fid=37530&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20536352%26dopt%3DAbstract Authors: Chaconas G, Kobryn K Spirochetes of the genus Borrelia include important human pathogens that cause Lyme borreliosis and relapsing fever. The genomes of Borrelia species can be composed of up to 24 DNA molecules, most of which are linear. The plasmid content and linear replicon sequence arrangement vary widely between isolates. The linear replicons are terminated by covalently closed DNA hairpins or hairpin telomeres. Replication of these elements involves a unique reaction, called telomere resolution, to produce hairpin telomeres from replicative intermediates. The telomere resolvase, ResT, is thought to contribute to the genetic flux of the linear molecules by promoting stabilized telomere fusions. Telomere resolvases are related to the tyrosine recombinases and ResT can gen... Annual Review of Microbiology journals http://www.medworm.com/rss/comments.php?id=3655848 Wed, 09 Jun 2010 23:00:00 +0100 3655848 http://www.medworm.com/index.php?rid=3655850&cid=s_37530_77_f&fid=37530&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20533875%26dopt%3DAbstract Authors: Rodriguez-Romero J, Hedtke M, Kastner C, Müller S, Fischer R Light is one of the most important environmental factors for orientation of almost all organisms on Earth. Whereas light sensing is of crucial importance in plants to optimize light-dependent energy conservation, in nonphotosynthetic organisms, the synchronization of biological clocks to the length of a day is an important function. Filamentous fungi may use the light signal as an indicator for the exposure of hyphae to air and adapt their physiology to this situation or induce morphogenetic pathways. Although a yes/no decision appears to be sufficient for the light-sensing function in fungi, most species apply a number of different, wavelength-specific receptors. The core of all receptor types is a chromophore, a... Annual Review of Microbiology journals http://www.medworm.com/rss/comments.php?id=3655850 Tue, 08 Jun 2010 23:00:00 +0100 3655850 http://www.medworm.com/index.php?rid=3655849&cid=s_37530_77_f&fid=37530&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20533876%26dopt%3DAbstract Authors: Miyata M Mycoplasma, a genus of pathogenic bacteria, forms a membrane protrusion at a cell pole. It binds to solid surfaces with this protrusion and then glides. The mechanism is not related to known bacterial motility systems, such as flagella or pili, or to conventional motor proteins, including myosin. We have studied the fastest species, Mycoplasma mobile, and have proposed a working model as follows. The gliding machinery is composed of four huge proteins at the base of the membrane protrusion and supported by a cytoskeletal architecture from the cell inside. Many flexible legs approximately 50 nm long are sticking out from the machinery. The movements generated by the ATP hydrolysis cell inside are transmitted to the "leg" protein through a "gear" protein, resulting in r... Annual Review of Microbiology journals http://www.medworm.com/rss/comments.php?id=3655849 Tue, 08 Jun 2010 23:00:00 +0100 3655849 http://www.medworm.com/index.php?rid=3655858&cid=s_37530_77_f&fid=37530&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20528687%26dopt%3DAbstract Authors: Shiflett AM, Johnson PJ The discovery of mitochondrion-type genes in organisms thought to lack mitochondria led to the demonstration that hydrogenosomes share a common ancestry with mitochondria, as well as the discovery of mitosomes in multiple eukaryotic lineages. No examples of examined eukaryotes lacking a mitochondrion-related organelle exist, implying that the endosymbiont that gave rise to the mitochondrion was present in the first eukaryote. These organelles, known as hydrogenosomes, mitosomes, or mitochondrion-like organelles, are typically reduced, both structurally and biochemically, relative to classical mitochondria. However, despite their diversification and adaptation to different niches, all appear to play a role in Fe-S cluster assembly, as observed for mitoch... Annual Review of Microbiology journals http://www.medworm.com/rss/comments.php?id=3655858 Sun, 06 Jun 2010 23:00:00 +0100 3655858 http://www.medworm.com/index.php?rid=3655857&cid=s_37530_77_f&fid=37530&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20528688%26dopt%3DAbstract Authors: Lewis K Persisters are dormant variants of regular cells that form stochastically in microbial populations and are highly tolerant to antibiotics. High persister (hip) mutants of Pseudomonas aeruginosa are selected in patients with cystic fibrosis. Similarly, hip mutants of Candida albicans are selected in patients with an oral thrush biofilm. These observations suggest that persisters may be the main culprit responsible for the recalcitrance of chronic infectious disease to antimicrobial therapy. Screening knockout libraries has not produced mutants lacking persisters, indicating that dormancy mechanisms are redundant. Toxin/antitoxin (TA) modules are involved in persister formation in Escherichia coli. The SOS response leads to overexpression of the TisB toxin and persister ... Annual Review of Microbiology journals http://www.medworm.com/rss/comments.php?id=3655857 Sun, 06 Jun 2010 23:00:00 +0100 3655857 http://www.medworm.com/index.php?rid=3655856&cid=s_37530_77_f&fid=37530&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20528689%26dopt%3DAbstract Authors: Kentner D, Sourjik V Following the introduction of fluorescent protein tags, the application of fluorescence microscopy in microbial cell biology has advanced the field dramatically.Wenow understand that bacterial cells are not simple bags of enzymes but have complex internal structures, and that specific intracellular organization plays an important role in a number of processes, including signal transduction. The quantitative nature and high temporal resolution of fluorescence microscopy make it particularly useful for studies of intracellular dynamic systems, such as signaling networks. Applications of fluorescence microscopy in signaling are not limited to studying localization. Several techniques allow researchers to follow real-time dynamics of protein interactions, at s... Annual Review of Microbiology journals http://www.medworm.com/rss/comments.php?id=3655856 Sun, 06 Jun 2010 23:00:00 +0100 3655856 http://www.medworm.com/index.php?rid=3655855&cid=s_37530_77_f&fid=37530&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20528690%26dopt%3DAbstract Authors: Hatfull GF Viruses are powerful tools for investigating and manipulating their hosts, but the enormous size and amazing genetic diversity of the bacteriophage population have emerged as something of a surprise. In light of the evident importance of mycobacteria to human health-especially Mycobacterium tuberculosis, which causes tuberculosis-and the difficulties that have plagued their genetic manipulation, mycobacteriophages are especially appealing subjects for discovery, genomic characterization, and manipulation. With more than 70 complete genome sequences available, the mycobacteriophages have provided a wealth of information on the diversity of phages that infect a common bacterial host, revealed the pervasively mosaic nature of phage genome architectures, and identified ... Annual Review of Microbiology journals http://www.medworm.com/rss/comments.php?id=3655855 Sun, 06 Jun 2010 23:00:00 +0100 3655855 http://www.medworm.com/index.php?rid=3655854&cid=s_37530_77_f&fid=37530&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20528691%26dopt%3DAbstract Authors: Galyov EE, Brett PJ, Deshazer D Burkholderia pseudomallei and Burkholderia mallei are closely related gram-negative bacteria that can cause serious diseases in humans and animals. This review summarizes the current and rapidly expanding knowledge on the specific virulence factors employed by these pathogens and their roles in the pathogenesis of melioidosis and glanders. In particular, the contributions of recently identified virulence factors are described in the context of the intracellular lifestyle of these pathogens. Throughout this review, unique and shared virulence features of B. pseudomallei and B. mallei are discussed. Expected final online publication date for the Annual Review of Microbiology Volume 64 is September 08, 2010. Please see http://www.annualreviews.org/... Annual Review of Microbiology journals http://www.medworm.com/rss/comments.php?id=3655854 Sun, 06 Jun 2010 23:00:00 +0100 3655854 http://www.medworm.com/index.php?rid=3655853&cid=s_37530_77_f&fid=37530&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20528692%26dopt%3DAbstract Authors: Ferry JG Methane produced in the biosphere is derived from two major pathways. Conversion of the methyl group of acetate to CH(4) in the aceticlastic pathway accounts for at least two-thirds, and reduction of CO(2) with electrons derived from H(2), formate, or CO accounts for approximately one-third. Although both pathways have terminal steps in common, they diverge considerably in the initial steps and energy conservation mechanisms. Steps and enzymes unique to the CO(2) reduction pathway are confined to methanogens and the domain Archaea. On the other hand, steps and enzymes unique to the aceticlastic pathway are widely distributed in the domain Bacteria, the understanding of which has contributed to a broader understanding of prokaryotic biology. Expected final online publi... Annual Review of Microbiology journals http://www.medworm.com/rss/comments.php?id=3655853 Sun, 06 Jun 2010 23:00:00 +0100 3655853 http://www.medworm.com/index.php?rid=3655852&cid=s_37530_77_f&fid=37530&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20528693%26dopt%3DAbstract Authors: Deveau H, Garneau JE, Moineau S Clustered regularly interspaced short palindromic repeats (CRISPR) along with Cas proteins is a widespread system across bacteria and archaea that causes interference against foreign nucleic acids. The CRISPR/Cas system acts in at least two general stages: the adaptation stage, where the cell acquires new spacer sequences derived from foreign DNA, and the interference stage, which uses the recently acquired spacers to target and cleave invasive nucleic acid. The CRISPR/Cas system participates in a constant evolutionary battle between phages and bacteria through addition or deletion of spacers in host cells and mutations or deletion in phage genomes. This review describes the recent progress made in this fast-expanding field. Expected final onlin... Annual Review of Microbiology journals http://www.medworm.com/rss/comments.php?id=3655852 Sun, 06 Jun 2010 23:00:00 +0100 3655852 http://www.medworm.com/index.php?rid=3655851&cid=s_37530_77_f&fid=37530&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20528694%26dopt%3DAbstract Authors: Cushion MT, Stringer JR Pneumocystis species are ascomycetous fungi that obligatorily dwell with no apparent ill effect in the lungs of normal mammals, but they become pathogenic when host defenses are compromised. Identified more than 100 years ago, these atypical fungi manifest characteristics that are unique within the Fungi, such as the lack of ergosterol, genetic complexity of surface antigens, and antigenic variation. Thought to be confined to the severely immunocompromised host, Pneumocystis spp. are being associated with new population niches owing to the advent of immunomodulatory therapies and increased numbers of patients suffering from chronic diseases. The inability to grow Pneumocystis spp. outside the mammalian lung has thwarted progress toward understanding the... Annual Review of Microbiology journals http://www.medworm.com/rss/comments.php?id=3655851 Sun, 06 Jun 2010 23:00:00 +0100 3655851 http://www.medworm.com/index.php?rid=3582088&cid=s_37530_77_f&fid=37530&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20477536%26dopt%3DAbstract Authors: Skalsky RL, Cullen BR One of the most significant recent advances in biomedical research has been the discovery of the approximately 22-nt-long class of noncoding RNAs designated microRNAs (miRNAs). These regulatory RNAs provide a unique level of posttranscriptional gene regulation that modulates a range of fundamental cellular processes. Several viruses, especially herpesviruses, also encode miRNAs, and over 200 viral miRNAs have now been identified. Current evidence indicates that viruses use these miRNAs to manipulate both cellular and viral gene expression. Furthermore, viral infection can exert a profound impact on the cellular miRNA expression profile, and several RNA viruses have been reported to interact directly with cellular miRNAs and/or to use these miRNAs to augme... Annual Review of Microbiology journals http://www.medworm.com/rss/comments.php?id=3582088 Sun, 16 May 2010 23:00:00 +0100 3582088 http://www.medworm.com/index.php?rid=3515687&cid=s_37530_77_f&fid=37530&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20420520%26dopt%3DAbstract Authors: Schiller JT, Lowy DR It has been estimated that viruses are etiological agents in approximately 12% of human cancers. Most of these cancers can be attributed to infections by human papillomavirus (HPV), hepatitis B virus (HBV), hepatitis C virus (HCV), Epstein-Barr virus (EBV), and Kaposi's sarcoma-associated herpesvirus (KSHV). Prophylactic vaccines against other pathogenic viruses have an excellent record as public health interventions in terms of safety, effectiveness, and ability to reach economically disadvantaged populations. These considerations should prompt efforts to develop and implement vaccines against oncoviruses. Safe and effective HBV and HPV vaccines, based on virus-like particles, are commercially available, and the major focus is now on vaccine delivery, esp... Annual Review of Microbiology journals http://www.medworm.com/rss/comments.php?id=3515687 Sun, 25 Apr 2010 23:00:00 +0100 3515687 http://www.medworm.com/index.php?rid=3515686&cid=s_37530_77_f&fid=37530&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20420521%26dopt%3DAbstract Authors: Ornston LN This reminiscence is a celebration of my good fortune in family, biological and scientific. The biological family into which I was born gave me a strong start, although not entirely in the direction I took. I swerved from an anticipated career in medical practice into continuing delight in those who became my scientific family in microbiology. The families changed, yet they continued to give me strength and inspiration. In my youth, I was gently guided by mentors who gave me freedom to explore where curiosity beckoned. I hope I repaid this gift to my laboratory colleagues who enlightened me over the years. I learned much from my students, and my horizons were extended by industrial scientists. It has been my particular good fortune to learn the workings of microorga... Annual Review of Microbiology journals http://www.medworm.com/rss/comments.php?id=3515686 Sun, 25 Apr 2010 23:00:00 +0100 3515686 http://www.medworm.com/index.php?rid=3515685&cid=s_37530_77_f&fid=37530&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20420522%26dopt%3DAbstract Authors: Noinaj N, Guillier M, Barnard TJ, Buchanan SK TonB-dependent transporters (TBDTs) are bacterial outer membrane proteins that bind and transport ferric chelates, called siderophores, as well as vitamin B(12), nickel complexes, and carbohydrates. The transport process requires energy in the form of proton motive force and a complex of three inner membrane proteins, TonB-ExbB-ExbD, to transduce this energy to the outer membrane. The siderophore substrates range in complexity from simple small molecules such as citrate to large proteins such as serum transferrin and hemoglobin. Because iron uptake is vital for almost all bacteria, expression of TBDTs is regulated in a number of ways that include metal-dependent regulators, sigma/anti-sigma factor systems, small RNAs, and even a ri... Annual Review of Microbiology journals http://www.medworm.com/rss/comments.php?id=3515685 Sun, 25 Apr 2010 23:00:00 +0100 3515685 http://www.medworm.com/index.php?rid=2562859&cid=s_37530_77_f&fid=37530&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19566421%26dopt%3DAbstract Authors: Straight PD, Kolter R Our view of bacteria, from the earliest observations through the heyday of antibiotic discovery, has shifted dramatically.We recognize communities of bacteria as integral and functionally important components of diverse habitats, ranging from soil collectives to the human microbiome. To function as productive communities, bacteria coordinate metabolic functions, often requiring shifts in growth and development. The hallmark of cellular development, which we characterize as physiological change in response to environmental stimuli, is a defining feature of many bacterial interspecies interactions. Bacterial communities rely on chemical exchanges to provide the cues for developmental change. Traditional methods in microbiology focus on isolation and charact... Annual Review of Microbiology journals http://www.medworm.com/rss/comments.php?id=2562859 Mon, 29 Jun 2009 23:00:00 +0100 2562859 http://www.medworm.com/index.php?rid=2473824&cid=s_37530_77_f&fid=37530&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19514844%26dopt%3DAbstract Authors: Chistoserdova L, Kalyuzhnaya MG, Lidstrom ME In the past few years, the field of methylotrophy has undergone a significant transformation in terms of discovery of novel types of methylotrophs, novel modes of methylotrophy, and novel metabolic pathways. This time has also been marked by the resolution of long-standing questions regarding methylotrophy and the challenge of long-standing dogmas. This chapter is not intended to provide a comprehensive review of metabolism of methylotrophic bacteria. Instead we focus on significant recent discoveries that are both refining and transforming the current understanding of methylotrophy as a metabolic phenomenon. We also review new directions in methylotroph ecology that improve our understanding of the role of methylotrophy in global b... Annual Review of Microbiology journals http://www.medworm.com/rss/comments.php?id=2473824 Wed, 10 Jun 2009 04:00:00 +0100 2473824 http://www.medworm.com/index.php?rid=2473822&cid=s_37530_77_f&fid=37530&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19514845%26dopt%3DAbstract Authors: Bonfante P, Anca IA This review focuses on interactions among plants, mycorrhizal fungi, and bacteria, testing the hypothesis whether mycorrhizas can be defined as tripartite associations. After summarizing the main biological features of mycorrhizas, we illustrate the different types of interaction occurring between mycorrhizal fungi and bacteria, from loosely associated microbes to endobacteria. We then discuss, in the context of nutritional strategies, the mechanisms that operate among members of the consortium and that often promote plant growth. Release of active molecules, including volatiles, and physical contact among the partners seem important for the establishment of the bacteria/mycorrhizal fungus/ plant network. The potential involvement of quorum sensing and Type... Annual Review of Microbiology journals http://www.medworm.com/rss/comments.php?id=2473822 Wed, 10 Jun 2009 04:00:00 +0100 2473822 http://www.medworm.com/index.php?rid=2473820&cid=s_37530_77_f&fid=37530&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19514852%26dopt%3DAbstract Authors: Kolstø AB, Tourasse NJ, Okstad OA Bacillus anthracis is the cause of anthrax, and two large plasmids are essential for toxicity: pXO1, which contains the toxin genes, and pXO2, which encodes a capsule. B. anthracis forms a highly monomorphic lineage within the B. cereus group, but strains of Bacillus thuringiensis and B. cereus exist that are genetically closely related to the B. anthracis cluster. During the past five years B. cereus strains that contain the pXO1 virulence plasmid were discovered, and strains with both pXO1 and pXO2 have been isolated from great apes in Africa. Therefore, the presence of pXO1 and pXO2 no longer principally separates B. anthracis from other Bacilli. The B. anthracis lineage carries a specific mutation in the global regulator PlcR, which c... Annual Review of Microbiology journals http://www.medworm.com/rss/comments.php?id=2473820 Wed, 10 Jun 2009 04:00:00 +0100 2473820 http://www.medworm.com/index.php?rid=2473817&cid=s_37530_77_f&fid=37530&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19514853%26dopt%3DAbstract Authors: Wagner M An astonishing diversity of microorganisms thrives on our planet and their activities are fundamental for the functioning of all ecosystems including the human body. Consequently, detailed insights into the functions performed by microorganisms in their natural environment are required to understand human biology and the biology of the world around us and to lay the foundations for targeted manipulation of microbial communities. Isotope-labeling techniques combined with molecular detection tools are frequently used by microbial ecologists to directly link structure and function of microbial communities and to monitor metabolic properties of uncultured microbes at the single-cell level. However, only the recent combination of such techniques with Raman microspectroscop... Annual Review of Microbiology journals http://www.medworm.com/rss/comments.php?id=2473817 Wed, 10 Jun 2009 04:00:00 +0100 2473817 http://www.medworm.com/index.php?rid=2473815&cid=s_37530_77_f&fid=37530&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19514854%26dopt%3DAbstract Authors: Hood HM, Neafsey DE, Galagan J, Sachs MS Upstream open reading frames (uORFs) are frequently present in the 5'- leader regions of fungal mRNAs. They can affect translation by controlling the ability of ribosomes that scan from the mRNA 5' end to reach the downstream genic reading frame. The translation of uORFs can also affect mRNA stability. For several genes, including Saccharomyces cerevisiae GCN4, S. cerevisiae CPA1, and Neurospora crassa arg-2, regulation by uORFs controls expression in response to specific physiological signals. The roles of many uORFs that are identified by genome-level approaches, as have been initiated for Saccharomyces, Aspergillus, and Cryptococcus species, remain to be determined. Some uORFs may have regulatory roles, while others may exist to insu... Annual Review of Microbiology journals http://www.medworm.com/rss/comments.php?id=2473815 Wed, 10 Jun 2009 04:00:00 +0100 2473815 http://www.medworm.com/index.php?rid=2473826&cid=s_37530_77_f&fid=37530&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19450140%26dopt%3DAbstract Authors: Rhome R, Del Poeta M Lipid signaling in pathogenic fungi has been studied to determine the role of these pathways in fungal biology and human infections. Owing to their unique nature, they may represent targets for future antifungal treatments. Farnesol signaling was characterized as a quorum-sensing molecule, with exposure inhibiting filamentation. Research has shown involvement in both the Ras1-adenylate cyclase and MAP kinase pathways. In species of Aspergillus, farnesol exposure induces apoptosis-like changes and alterations in ergosterol synthesis. Eicosanoid production has been characterized in several pathogenic fungi, utilizing host lipids in some cases. The role in virulence is not known yet, but it may involve modulation of host lipids. Sphingolipid signaling pathway... Annual Review of Microbiology journals http://www.medworm.com/rss/comments.php?id=2473826 Mon, 18 May 2009 04:00:00 +0100 2473826 http://www.medworm.com/index.php?rid=2473829&cid=s_37530_77_f&fid=37530&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19385726%26dopt%3DAbstract Authors: Tumpey TM, Belser JA Influenza viruses continue to pose a major global public health problem. There is a need to better understand the pathogenicity and transmission of pandemic influenza viruses so that we may develop improved methods for their prevention and control. Reconstruction of the 1918 virus and studies elucidating the exceptional virulence and transmissibility of the virus are providing exciting new insights into this devastating pandemic strain. The primary approach has been to reconstruct and analyze recombinant viruses, in which genes of the 1918 virus are replaced with genes of contemporary influenza viruses of lesser virulence. This review highlights the current status of the field and discusses the molecular determinants of the 1918 pandemic virus that may hav... Annual Review of Microbiology journals http://www.medworm.com/rss/comments.php?id=2473829 Wed, 22 Apr 2009 04:00:00 +0100 2473829 http://www.medworm.com/index.php?rid=2473828&cid=s_37530_77_f&fid=37530&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19385727%26dopt%3DAbstract Authors: Babitzke P, Baker CS, Romeo T RNA binding proteins are capable of regulating translation initiation by a variety of mechanisms. Although the vast majority of these regulatory mechanisms involve translational repression, one example of translational activation has been characterized in detail. The RNA recognition targets of these regulatory proteins exhibit a wide range in structural complexity, with some proteins recognizing complex pseudoknot structures and others binding to simple RNA hairpins and/or short repeated single-stranded sequences. In some instances the bound protein directly competes with ribosome binding, and in other instances the bound protein promotes formation of an RNA structure that inhibits ribosome binding. Examples also exist in which the bound protein t... Annual Review of Microbiology journals http://www.medworm.com/rss/comments.php?id=2473828 Wed, 22 Apr 2009 04:00:00 +0100 2473828 http://www.medworm.com/index.php?rid=2473831&cid=s_37530_77_f&fid=37530&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19379069%26dopt%3DAbstract Authors: Ling J, Reynolds N, Ibba M Translating the 4-letter code of RNA into the 22-letter alphabet of proteins is a central feature of cellular life. The fidelity with which mRNA is translated during protein synthesis is determined by two factors: the availability of aminoacyl-tRNAs composed of cognate amino acid:tRNA pairs and the accurate selection of aminoacyl-tRNAs on the ribosome. The role of aminoacyl-tRNA synthetases in translation is to define the genetic code by accurately pairing cognate tRNAs with their corresponding amino acids. Synthetases achieve the amino acid substrate specificity necessary to keep errors in translation to an acceptable level in two ways: preferential binding of the cognate amino acid and selective editing of near-cognate amino acids. Editing signific... Annual Review of Microbiology journals http://www.medworm.com/rss/comments.php?id=2473831 Mon, 20 Apr 2009 04:00:00 +0100 2473831 http://www.medworm.com/index.php?rid=2473830&cid=s_37530_77_f&fid=37530&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19379070%26dopt%3DAbstract Authors: Kirby JR Bacteria sense the chemical world using a variety of mechanisms that include the frequently described two-component system (TCS), which comprises a sensor kinase and response regulator, to regulate gene expression in response to environmental cues. One of the best and most widely studied versions of the TCS is the system that controls chemotaxis in Escherichia coli. The chemotaxis machinery includes components not found in other TCS to regulate motility and is therefore an exception to the rule for two-component signaling. The hallmark feature of the chemotaxis system is the presence of an adaptation module in which the sensor receptor protein is posttranslationally modified to attenuate ligand-induced signaling, a mechanism not yet identified for the more widely dist... Annual Review of Microbiology journals http://www.medworm.com/rss/comments.php?id=2473830 Mon, 20 Apr 2009 04:00:00 +0100 2473830 http://www.medworm.com/index.php?rid=1789360&cid=s_37530_77_f&fid=37530&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18785836%26dopt%3DAbstract Authors: Casadevall A The evolution of intracellular pathogens is considered in the context of ambiguities in basic definitions and the diversity of host-microbe interactions. Intracellular pathogenesis is a subset of a larger world of host-microbe interactions that includes amoeboid predation and endosymbiotic existence. Intracellular pathogens often reveal genome reduction. Despite the uniqueness of each host-microbe interaction, there are only a few general solutions to the problem of intracellular survival, especially in phagocytic cells. Similarities in intracellular pathogenic strategies between phylogenetically distant microbes suggest convergent evolution. For discerning such patterns, it is useful to consider whether the microbe is acquired from another host or directly from t... Annual Review of Microbiology journals http://www.medworm.com/rss/comments.php?id=1789360 Sat, 13 Sep 2008 15:16:55 +0100 1789360 http://www.medworm.com/index.php?rid=1789359&cid=s_37530_77_f&fid=37530&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18785837%26dopt%3DAbstract Authors: Achtman M Genetically monomorphic bacteria contain so little sequence diversity that sequencing a few gene fragments yields little or no information. As a result, our understanding of their evolutionary patterns presents greater technical challenges than exist for genetically diverse microbes. These challenges are now being met by analyses at the genomic level for diverse types of genetic variation, the most promising of which are single nucleotide polymorphisms. Many of the most virulent bacterial pathogens are genetically monomorphic, and understanding their evolutionary and phylogeographic patterns will help our understanding of the effects of infectious disease on human history. PMID: 18785837 [PubMed - as supplied by publisher] (Source: Annual Review of Microbiology) Annual Review of Microbiology journals http://www.medworm.com/rss/comments.php?id=1789359 Sat, 13 Sep 2008 15:16:50 +0100 1789359 http://www.medworm.com/index.php?rid=1789358&cid=s_37530_77_f&fid=37530&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18785838%26dopt%3DAbstract Authors: van der Woude MW, Henderson IR Antigen 43 (Ag43) is an abundant outer membrane protein in Escherichia coli belonging to the autotransporter family. Structure-function relationships of Ag43 proposed on the basis of experimental work and in silico analysis are discussed in context of insights derived from molecular modeling. New sequence analysis sheds light on the phylogeny of the allelic variants of the Ag43-encoding gene and identifies two distinct families that appear to be distributed between specific pathogenic and commensal isolates. The molecular mechanism that controls expression by phase variation to create population heterogeneity is discussed. Proposed roles of Ag43 expression for E. coli are summarized and the studies are put into perspective regarding the role of a... Annual Review of Microbiology journals http://www.medworm.com/rss/comments.php?id=1789358 Sat, 13 Sep 2008 15:16:47 +0100 1789358 http://www.medworm.com/index.php?rid=1789357&cid=s_37530_77_f&fid=37530&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18785839%26dopt%3DAbstract Authors: Deng Q, Barbieri JT Bacterial pathogens utilize toxins to modify or kill host cells. The bacterial ADP-ribosyltransferases are a family of protein toxins that covalently transfer the ADP-ribose portion of NAD to host proteins. Each bacterial ADP-ribosyltransferase toxin modifies a specific host protein(s) that yields a unique pathology. These toxins possess the capacity to enter a host cell or to use a bacterial Type III apparatus for delivery into the host cell. Advances in our understanding of bacterial toxin action parallel the development of biophysical and structural biology as well as our understanding of the mammalian cell. Bacterial toxins have been utilized as vaccines, as tools to dissect host cell physiology, and more recently for the development of novel therapies ... Annual Review of Microbiology journals http://www.medworm.com/rss/comments.php?id=1789357 Sat, 13 Sep 2008 15:16:40 +0100 1789357 http://www.medworm.com/index.php?rid=1789356&cid=s_37530_77_f&fid=37530&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18785840%26dopt%3DAbstract Authors: Holmes EC Understanding the evolutionary history of human viruses, along with the factors that have shaped their spatial distributions, is one of the most active areas of study in the field of microbial evolution. I give an overview of our current knowledge of the genetic diversity of human viruses using comparative studies of viral populations, particularly those with RNA genomes, to highlight important generalities in the patterns and processes of viral evolution. Special emphasis is given to the major dichotomy between RNA and DNA viruses in their epidemiological dynamics and the different types of phylogeographic pattern exhibited by human viruses. I also consider a central paradox in studies of viral evolution: Although epidemiological theory predicts that RNA viruses hav... Annual Review of Microbiology journals http://www.medworm.com/rss/comments.php?id=1789356 Sat, 13 Sep 2008 15:16:37 +0100 1789356 http://www.medworm.com/index.php?rid=1789355&cid=s_37530_77_f&fid=37530&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18785841%26dopt%3DAbstract Authors: Naffakh N, Tomoiu A, Rameix-Welti MA, van der Werf S Although transmission of avian influenza viruses to mammals, particularly humans, has been repeatedly documented, adaptation and sustained transmission in the new host is a rare event that in the case of humans may result in pandemics. Host restriction involves multiple genetic determinants. Among the known determinants of host range, key determinants have been identified on the genes coding for the nucleoprotein and polymerase proteins that, together with the viral RNA segments, form the ribonucleoproteins (RNPs). The RNP genes form host-specific lineages and harbor host-associated genetic signatures. The functional significance of these determinants has been studied by reassortment and reverse genetics experiments, underli... Annual Review of Microbiology journals http://www.medworm.com/rss/comments.php?id=1789355 Sat, 13 Sep 2008 15:16:33 +0100 1789355 http://www.medworm.com/index.php?rid=1789354&cid=s_37530_77_f&fid=37530&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18785842%26dopt%3DAbstract Authors: Carter CA, Ehrlich LS HIV infection of macrophages is a critically important component of viral pathogenesis and progression to AIDS. Although the virus follows the same life cycle in macrophages and T lymphocytes, several aspects of the virus-host relationship are unique to macrophage infection. Examples of these are the long-term persistence of productive infection, sustained by the absence of cell death, and the ability of progeny virus to bud into and accumulate in endocytic compartments designated multivesicular bodies (MVBs). Recently, the hypothesis that viral exploitation of the macrophage endocytic machinery is responsible for perpetuating the chronic state of infection unique to this cell type has been challenged in several independent studies employing a variety of ... Annual Review of Microbiology journals http://www.medworm.com/rss/comments.php?id=1789354 Sat, 13 Sep 2008 15:16:30 +0100 1789354 http://www.medworm.com/index.php?rid=1789353&cid=s_37530_77_f&fid=37530&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18785843%26dopt%3DAbstract Authors: Scherf A, Lopez-Rubio JJ, Riviere L The persistence of the human malaria parasite Plasmodium falciparum during blood stage proliferation in its host depends on the successive expression of variant molecules at the surface of infected erythrocytes. This variation is mediated by the differential control of a family of surface molecules termed PfEMP1 encoded by approximately 60 var genes. Each individual parasite expresses a single var gene at a time, maintaining all other members of the family in a transcriptionally silent state. PfEMP1/var enables parasitized erythrocytes to adhere within the microvasculature, resulting in severe disease. This review highlights key regulatory mechanisms thought to be critical for monoallelic expression of var genes. Antigenic variation is orche... Annual Review of Microbiology journals http://www.medworm.com/rss/comments.php?id=1789353 Sat, 13 Sep 2008 15:16:27 +0100 1789353 http://www.medworm.com/index.php?rid=1789352&cid=s_37530_77_f&fid=37530&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18785844%26dopt%3DAbstract Authors: Plattner F, Soldati-Favre D Intracellular pathogens such as viruses and bacteria subvert all the major cellular functions of their hosts. Targeted host processes include protein synthesis, membrane trafficking, modulation of gene expression, antigen presentation, and apoptosis. In recent years, it has become evident that protozoan pathogens, including members of the phylum Apicomplexa, also hijack their host cell's functions to access nutrients and to escape cellular defenses and immune responses. These obligate intracellular parasites provide superb illustrations of the subversion of host cell processes such as the recruitment and reorganization of host cell compartments without fusion around the parasitophorous vacuole of Toxoplasma gondii; the export of Plasmodium falciparu... Annual Review of Microbiology journals http://www.medworm.com/rss/comments.php?id=1789352 Sat, 13 Sep 2008 15:16:24 +0100 1789352 http://www.medworm.com/index.php?rid=1583695&cid=s_37530_77_f&fid=37530&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18557701%26dopt%3DAbstract Authors: Keiler KC The trans-translation mechanism is a key component of multiple quality control pathways in bacteria that ensure proteins are synthesized with high fidelity in spite of challenges such as transcription errors, mRNA damage, and translational frameshifting. trans-Translation is performed by a ribonucleoprotein complex composed of tmRNA, a specialized RNA with properties of both a tRNA and an mRNA, and the small protein SmpB. tmRNA-SmpB interacts with translational complexes stalled at the 3' end of an mRNA to release the stalled ribosomes and target the nascent polypeptides and mRNAs for degradation. In addition to quality control pathways, some genetic regulatory circuits use trans-translation to control gene expression. Diverse bacteria require trans-translation when ... Annual Review of Microbiology journals http://www.medworm.com/rss/comments.php?id=1583695 Mon, 16 Jun 2008 04:00:00 +0100 1583695 http://www.medworm.com/index.php?rid=1583698&cid=s_37530_77_f&fid=37530&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18544039%26dopt%3DAbstract Authors: Sibley LD, Ajioka JW Toxoplasma gondii is among the most successful parasites. It is capable of infecting all warm-blooded animals and causing opportunistic disease in humans. T. gondii has a striking clonal population structure consisting of three predominant lineages in North America and Europe. Clonality is associated with the recent emergence of a monomorphic version of Chr1a, which drove a selective genetic sweep within the past 10,000 years. Strains from South America diverged from those in North America some 1-2 mya; recently, however, the monomorphic Chr1a has extended into regions of South America, where it is also associated with clonality. The recent spread of a few dominant lineages has dramatically shaped the population structure of T. gondii and has resulted in m... Annual Review of Microbiology journals http://www.medworm.com/rss/comments.php?id=1583698 Tue, 10 Jun 2008 04:00:00 +0100 1583698 http://www.medworm.com/index.php?rid=1583697&cid=s_37530_77_f&fid=37530&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18544040%26dopt%3DAbstract We describe current approaches to study microbial ecology and progress toward predictive modeling. Expected final online publication date for the Annual Review of Microbiology Volume 62 is September 08, 2008. Please see http://www.annualreviews.org/catalog/pubdates.aspx for revised estimates. PMID: 18544040 [PubMed - as supplied by publisher] (Source: Annual Review of Microbiology) Annual Review of Microbiology journals http://www.medworm.com/rss/comments.php?id=1583697 Tue, 10 Jun 2008 04:00:00 +0100 1583697 http://www.medworm.com/index.php?rid=1583696&cid=s_37530_77_f&fid=37530&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18544041%26dopt%3DAbstract Authors: Youngman EM, McDonald ME, Green R Peptide release, the reaction that hydrolyzes a completed protein from the peptidyl-tRNA upon completion of translation, is catalyzed in the active site of the large subunit of the ribosome and requires a class I release factor protein. The ribosome and release factor protein cooperate to accomplish two tasks: recognition of the stop codon and catalysis of peptidyl-tRNA hydrolysis. Although many fundamental questions remain, substantial progress has been made in the past several years. This review summarizes those advances and presents current models for the mechanisms of stop codon specificity and catalysis of peptide release. Finally, we discuss how these views fit into a larger emerging theme in the translation field: the importance of indu... Annual Review of Microbiology journals http://www.medworm.com/rss/comments.php?id=1583696 Tue, 10 Jun 2008 04:00:00 +0100 1583696 http://www.medworm.com/index.php?rid=1583700&cid=s_37530_77_f&fid=37530&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18537473%26dopt%3DAbstract Authors: Law CJ, Maloney PC, Wang DN The major facilitator superfamily (MFS) represents the largest group of secondary active membrane transporters, and its members transport a diverse range of substrates. Recent work shows that MFS antiporters, and perhaps all members of the MFS, share the same threedimensional structure, consisting of two domains that surround a substrate translocation pore. The advent of crystal structures of three MFS antiporters sheds light on their fundamental mechanism; they operate via a single binding site, alternating-access mechanism that involves a rocker-switch type movement of the two halves of the protein. In the sn-glycerol-3-phosphate transporter (GlpT) from Escherichia coli, the substrate-binding site is formed by several charged residues and a histid... Annual Review of Microbiology journals http://www.medworm.com/rss/comments.php?id=1583700 Fri, 06 Jun 2008 04:00:00 +0100 1583700 http://www.medworm.com/index.php?rid=1583699&cid=s_37530_77_f&fid=37530&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18537474%26dopt%3DAbstract Authors: Veening JW, Smits WK, Kuipers OP Clonal populations of microbial cells often show a high degree of phenotypic variability under homogeneous conditions. Stochastic fluctuations in the cellular components that determine cellular states can cause two distinct subpopulations, a property called bistability. Phenotypic heterogeneity can be readily obtained by interlinking multiple gene regulatory pathways, effectively resulting in a genetic logic-AND gate. Although switching between states can occur within the cells' lifetime, cells can also pass their cellular state over to the next generation by a mechanism known as epigenetic inheritance and thus perpetuate the phenotypic state. Importantly, heterogeneous populations often demonstrate increased fitness compared with homogeneous p... Annual Review of Microbiology journals http://www.medworm.com/rss/comments.php?id=1583699 Fri, 06 Jun 2008 04:00:00 +0100 1583699 http://www.medworm.com/index.php?rid=1583701&cid=s_37530_77_f&fid=37530&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18473699%26dopt%3DAbstract Authors: Horn M Members of the phylum Chlamydiae are obligate intracellular bacteria that were discovered about a century ago. Although Chlamydiae are major pathogens of humans and animals, they were long recognized only as a phylogenetically well-separated, small group of closely related microorganisms. The diversity of chlamydiae, their host range, and their occurrence in the environment had been largely underestimated. Today, several chlamydia-like bacteria have been described as symbionts of free-living amoebae and other eukaryotic hosts. Some of these environmental chlamydiae might also be of medical relevance for humans. Their analysis has contributed to a broader understanding of chlamydial biology and to novel insights into the evolution of these unique microorganisms. Expected... Annual Review of Microbiology journals http://www.medworm.com/rss/comments.php?id=1583701 Mon, 12 May 2008 04:00:00 +0100 1583701 http://www.medworm.com/index.php?rid=1583702&cid=s_37530_77_f&fid=37530&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18454629%26dopt%3DAbstract Authors: Potrykus K, Cashel M The fundamental details of how nutritional stress leads to elevating (p)ppGpp are questionable. By common usage, the meaning of the stringent response has evolved from the specific response to (p)ppGpp provoked by amino acid starvation to all responses caused by elevating (p)ppGpp by any means. Different responses have similar as well as dissimilar positive and negative effects on gene expression and metabolism. The different ways that different bacteria seem to exploit their capacities to form and respond to (p)ppGpp are already impressive despite an early stage of discovery. Apparently, (p)ppGpp can contribute to regulation of many aspects of microbial cell biology that are sensitive to changing nutrient availability: growth, adaptation, secondary metabo... Annual Review of Microbiology journals http://www.medworm.com/rss/comments.php?id=1583702 Fri, 02 May 2008 04:00:00 +0100 1583702 http://www.medworm.com/index.php?rid=1583704&cid=s_37530_77_f&fid=37530&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18429680%26dopt%3DAbstract Authors: Kyle JL, Harris E Dengue is a spectrum of disease caused by four serotypes of the most prevalent arthropod-borne virus affecting humans today, and its incidence has increased dramatically in the past 50 years. Due in part to population growth and uncontrolled urbanization in tropical and subtropical countries, breeding sites for the mosquitoes that transmit dengue virus have proliferated, and successful vector control has proven problematic. Dengue viruses have evolved rapidly as they have spread worldwide, and genotypes associated with increased virulence have expanded from South and Southeast Asia into the Pacific and the Americas. This review explores the human, mosquito, and viral factors that contribute to the global spread and persistence of dengue, as well as the intera... Annual Review of Microbiology journals http://www.medworm.com/rss/comments.php?id=1583704 Tue, 22 Apr 2008 04:00:00 +0100 1583704 http://www.medworm.com/index.php?rid=1583703&cid=s_37530_77_f&fid=37530&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18429691%26dopt%3DAbstract Authors: Rubio LM, Ludden PW The iron-molybdenum cofactor (FeMo-co), located at the active site of the molybdenum nitrogenase, is one of the most complex metal cofactors known to date. During the past several years, an intensive effort has been made to purify the proteins involved in FeMo-co synthesis and incorporation into nitrogenase. This effort is starting to provide the first insights into the structures of the FeMo-co biosynthetic intermediates and into the biochemical details of FeMo-co synthesis. Expected final online publication date for the Annual Review of Microbiology Volume 62 is September 08, 2008. Please see http://www.annualreviews.org/catalog/pubdates.aspx for revised estimates. PMID: 18429691 [PubMed - as supplied by publisher] (Source: Annual Review of Microbiolo... Annual Review of Microbiology journals http://www.medworm.com/rss/comments.php?id=1583703 Tue, 22 Apr 2008 04:00:00 +0100 1583703 http://www.medworm.com/index.php?rid=1583705&cid=s_37530_77_f&fid=37530&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18345978%26dopt%3DAbstract Authors: Falkow S My professional life can be summarized by a quote from the Talmud. Much have I learned from my teachers More from my colleagues, But most from my students. It is the fortunate professor who learns from the student. Expected final online publication date for the Annual Review of Microbiology Volume 62 is September 08, 2008. Please see http://www.annualreviews.org/catalog/pubdates.aspx for revised estimates. PMID: 18345978 [PubMed - as supplied by publisher] (Source: Annual Review of Microbiology) Annual Review of Microbiology journals http://www.medworm.com/rss/comments.php?id=1583705 Mon, 17 Mar 2008 04:00:00 +0100 1583705 http://www.medworm.com/index.php?rid=1583738&cid=s_37530_77_f&fid=37530&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D17439360%26dopt%3DAbstract Authors: Vilchèze C, Jacobs Jr WR Isoniazid (INH) is one of the most efficient drugs for the treatment of Mycobacterium tuberculosis infections. Despite its rather simple chemical structure, the mechanism by which INH kills M. tuberculosis is complex. A full understanding of the mechanisms of action of INH required the development of genetic tools in M. tuberculosis. Herein, we discuss the different hypotheses that have been used to describe INH action against M. tuberculosis over the past 50 years in terms of the pregenetic and genetic era. We also review the different mechanisms of INH resistance and propose what we think is the means by which INH kills M. tuberculosis. Expected online publication date for the Annual Review of Microbiology Volume 61 is September 8, 2007. Please ... Annual Review of Microbiology journals http://www.medworm.com/rss/comments.php?id=1583738 Tue, 17 Apr 2007 04:00:00 +0100 1583738 http://www.medworm.com/index.php?rid=1583737&cid=s_37530_77_f&fid=37530&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D17439361%26dopt%3DAbstract We present a model based on the word usage in books to illustrate the power of statistical tools in describing microbial communities and suggesting biological hypotheses. The model also generates data to test these methods when there are insufficient data in the literature. For example, by simulating the word distribution in books, we can predict the number of words that must be read to estimate the size of the vocabulary used to write the book. Combined with other models that have been used to make inaccessible problems tractable, our book model offers a unique approach to the complex problem of describing microbial diversity. PMID: 17439361 [PubMed - indexed for MEDLINE] (Source: Annual Review of Microbiology) Annual Review of Microbiology journals http://www.medworm.com/rss/comments.php?id=1583737 Mon, 01 Jan 2007 05:00:00 +0100 1583737 http://www.medworm.com/index.php?rid=1583736&cid=s_37530_77_f&fid=37530&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D17441785%26dopt%3DAbstract 40 years with bacteriophage ø29. Annu Rev Microbiol. 2007;61:1-22 Authors: Salas M I have dedicated the past 46 years of my life to science and I expect to be active in research for many more years. I have been lucky in my professional life. During my postdoctoral years I discovered two proteins that I showed to be involved in the initiation of protein synthesis. Working with bacteriophage ø29 for the past 40 years, we have made many interesting findings. Among them is the discovery of a protein covalently linked to the 5' ends of ø29 DNA that we later showed to be the primer for the initiation of ø29 DNA replication. Also, the finding of the ø29 DNA polymerase with its properties of high processivity, strand displacement, and high fidelity has been ver... Annual Review of Microbiology journals http://www.medworm.com/rss/comments.php?id=1583736 Mon, 01 Jan 2007 05:00:00 +0100 1583736 http://www.medworm.com/index.php?rid=1583735&cid=s_37530_77_f&fid=37530&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D17447862%26dopt%3DAbstract Authors: Carpousis AJ The RNA degradosome of Escherichia coli is a multiprotein complex involved in the degradation of mRNA. The principal components are RNase E, PNPase, RhlB, and enolase. RNase E is a large multidomain protein with an N-terminal catalytic region and a C-terminal noncatalytic region that is mostly natively unstructured protein. The noncatalytic region contains sites for binding RNA and for protein-protein interactions with other components of the RNA degradosome. Several recent studies suggest that there are alternative forms of the RNA degradosome depending on growth conditions or other factors. These alternative forms appear to modulate RNase E activity in the degradation of mRNA. RNA degradosome-like complexes appear to be conserved throughout the Proteobacteria, b... Annual Review of Microbiology journals http://www.medworm.com/rss/comments.php?id=1583735 Mon, 01 Jan 2007 05:00:00 +0100 1583735 http://www.medworm.com/index.php?rid=1583734&cid=s_37530_77_f&fid=37530&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D17456010%26dopt%3DAbstract Authors: Sariaslani FS Production of industrial aromatic chemicals from renewable resources could provide a competitive alternative to traditional chemical synthesis routes. This review describes the engineering of microorganisms for the production of p-hydroxycinnamic acid (pHCA) and p-hydroxystyrene (pHS) from glucose. The initial process concept was demonstrated using a tyrosine-producing Escherichia coli strain that overexpressed both fungal phenylalanine/tyrosine ammonia lyase (PAL) and bacterial pHCA decarboxylase (pdc) genes. Further development of this bioprocess resulted in uncoupling the pHCA and pHS production steps to mitigate their toxicity to the production host. The final process consists of a fermentation step to convert glucose to tyrosine using a tyrosine-overproducin... Annual Review of Microbiology journals http://www.medworm.com/rss/comments.php?id=1583734 Mon, 01 Jan 2007 05:00:00 +0100 1583734 http://www.medworm.com/index.php?rid=1583733&cid=s_37530_77_f&fid=37530&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D17480182%26dopt%3DAbstract Authors: Tamayo R, Pratt JT, Camilli A Cyclic diguanylate (c-di-GMP) is a bacterial second messenger of growing recognition involved in the regulation of a number of complex physiological processes. This review describes the biosynthesis and hydrolysis of c-di-GMP and several mechanisms of regulation of c-di-GMP metabolism. The contribution of c-di-GMP to regulating biofilm formation and motility, processes that affect pathogenesis of many bacteria, is described, as is c-di-GMP regulation of virulence gene expression. Finally, ways in which c-di-GMP may mediate these regulatory effects are proposed. PMID: 17480182 [PubMed - indexed for MEDLINE] (Source: Annual Review of Microbiology) Annual Review of Microbiology journals http://www.medworm.com/rss/comments.php?id=1583733 Mon, 01 Jan 2007 05:00:00 +0100 1583733 http://www.medworm.com/index.php?rid=1583732&cid=s_37530_77_f&fid=37530&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D17506668%26dopt%3DAbstract Authors: Mackenzie C, Eraso JM, Choudhary M, Roh JH, Zeng X, Bruscella P, Puskás A, Kaplan S This review describes some of the recent highlights taken from the studies of Rhodobacter sphaeroides 2.4.1. The review is not intended to be comprehensive, but to reflect the bias of the authors as to how the availability of a sequenced and annotated genome, a gene-chip, and proteomic profile as well as comparative genomic analyses can direct the progress of future research in this system. PMID: 17506668 [PubMed - indexed for MEDLINE] (Source: Annual Review of Microbiology) Annual Review of Microbiology journals http://www.medworm.com/rss/comments.php?id=1583732 Mon, 01 Jan 2007 05:00:00 +0100 1583732 http://www.medworm.com/index.php?rid=1583731&cid=s_37530_77_f&fid=37530&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D17506669%26dopt%3DAbstract Authors: Dautin N, Bernstein HD Autotransporters are a large and diverse superfamily of proteins produced by pathogenic gram-negative bacteria that are composed of an N-terminal passenger domain, which typically harbors a virulence function, and a C-terminal beta domain. It has long been known that the beta domain anchors the protein to the outer membrane and facilitates transport of the passenger domain into the extracellular space. Despite the apparent simplicity of the autotransporter pathway, several aspects of autotransporter biogenesis remain poorly understood, most notably the mechanism by which the passenger domain is translocated across the outer membrane. Here we review recent evidence that the enormous sequence diversity of both passenger and beta domains belies a remarkable... Annual Review of Microbiology journals http://www.medworm.com/rss/comments.php?id=1583731 Mon, 01 Jan 2007 05:00:00 +0100 1583731 http://www.medworm.com/index.php?rid=1583730&cid=s_37530_77_f&fid=37530&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D17506670%26dopt%3DAbstract Authors: Anantharaman V, Iyer LM, Aravind L Data from protist genomes suggest that eukaryotes show enormous variability in their gene complements, especially of genes coding regulatory proteins. Overall counts of eukaryotic signaling proteins show weak nonlinear scaling with proteome size, but individual superfamilies of signaling domains might show vast expansions in certain protists. Alteration of domain architectural complexity of signaling proteins and repeated lineage-specific reshaping of architectures might have played a major role in the emergence of new signaling interactions in different eukaryotes. Lateral transfer of various signaling domains from bacteria or from hosts, in parasites such as apicomplexans, appears to also have played a major role in the origin of new functi... Annual Review of Microbiology journals http://www.medworm.com/rss/comments.php?id=1583730 Mon, 01 Jan 2007 05:00:00 +0100 1583730 http://www.medworm.com/index.php?rid=1583729&cid=s_37530_77_f&fid=37530&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D17506671%26dopt%3DAbstract Authors: Arp DJ, Chain PS, Klotz MG The availability of whole-genome sequences for ammonia-oxidizing bacteria (AOB) has led to dramatic increases in our understanding of these environmentally important microorganisms. Their genomes are smaller than many other members of the proteobacteria and may indicate genome reductions consistent with their limited lifestyle. The genomes have a surprising level of gene repetition including genes for ammonia catabolism, iron acquisition, and insertion sequences. The gene profiles reveal limited genes for catabolism and transport of complex organic compounds, but complete pathways for some other compounds. This led to the observation of chemolithoheterotrophic growth of Nitrosomonas europaea. Genes for sucrose synthesis/degradation were identified. T... Annual Review of Microbiology journals http://www.medworm.com/rss/comments.php?id=1583729 Mon, 01 Jan 2007 05:00:00 +0100 1583729 http://www.medworm.com/index.php?rid=1583728&cid=s_37530_77_f&fid=37530&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D17506672%26dopt%3DAbstract Authors: Pitcher RS, Brissett NC, Doherty AJ In eukaryotic cells, repair of DNA double-strand breaks (DSBs) by the nonhomologous end-joining (NHEJ) pathway is critical for genomic stability. A functionally homologous repair apparatus, composed of Ku and a multifunctional DNA ligase (LigD), has recently been identified in many prokaryotes. Eukaryotic organisms employ a large number of factors to repair breaks by NHEJ. In contrast, the bacterial NHEJ complex is a two-component system that, despite its relative simplicity, possesses all of the break-recognition, end-processing, and ligation activities required to facilitate the complex task of DSB repair. Here, we review recent discoveries on the structure and function of the bacterial NHEJ repair apparatus. In particular, we discuss the ... Annual Review of Microbiology journals http://www.medworm.com/rss/comments.php?id=1583728 Mon, 01 Jan 2007 05:00:00 +0100 1583728 http://www.medworm.com/index.php?rid=1583727&cid=s_37530_77_f&fid=37530&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D17506673%26dopt%3DAbstract Authors: Li L, Wright SJ, Krystofova S, Park G, Borkovich KA Filamentous fungi are multicellular eukaryotic organisms known for nutrient recycling as well as for antibiotic and food production. This group of organisms also contains the most devastating plant pathogens and several important human pathogens. Since the first report of heterotrimeric G proteins in filamentous fungi in 1993, it has been demonstrated that G proteins are essential for growth, asexual and sexual development, and virulence in both animal and plant pathogenic filamentous species. Numerous G protein subunit and G protein-coupled receptor genes have been identified, many from whole-genome sequences. Several regulatory pathways have now been delineated, including those for nutrient sensing, pheromone response and m... Annual Review of Microbiology journals http://www.medworm.com/rss/comments.php?id=1583727 Mon, 01 Jan 2007 05:00:00 +0100 1583727 http://www.medworm.com/index.php?rid=1583726&cid=s_37530_77_f&fid=37530&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D17506674%26dopt%3DAbstract Authors: Graumann PL All cytoskeletal elements known from eukaryotic cells are also present in bacteria, where they perform vital tasks in many aspects of the physiology of the cell. Bacterial tubulin (FtsZ), actin (MreB), and intermediate filament (IF) proteins are key elements in cell division, chromosome and plasmid segregation, and maintenance of proper cell shape, as well as in maintenance of cell polarity and assembly of intracellular organelle-like structures. Although similar tasks are performed by eukaryotic cytoskeletal elements, the individual functions of FtsZ, MreBs, and IFs are different from those performed by their eukaryotic orthologs, revealing a striking evolutional plasticity of cytoskeletal proteins. However, similar to the functions of their eukaryotic counterpart... Annual Review of Microbiology journals http://www.medworm.com/rss/comments.php?id=1583726 Mon, 01 Jan 2007 05:00:00 +0100 1583726 http://www.medworm.com/index.php?rid=1583722&cid=s_37530_77_f&fid=37530&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D17506678%26dopt%3DAbstract Authors: Whiteway M, Bachewich C Candida albicans is termed a dimorphic fungus because it proliferates in either a yeast form or a hyphal form. The switch between these forms is the result of a complex interplay of external and internal factors and is coordinated in part by polarity-regulating proteins that are conserved among eukaryotic cells. However, yeast and hyphal cells are not the only morphological states of C. albicans. The opaque form required for mating, the pseudohyphal cell, and the chlamydospore represent distinct cell types that form in response to specific genetic or environmental conditions. In addition, hyperextended buds can form as a result of various cell cycle-related stresses. Recent studies are beginning to shed light on some of the molecular controls regulating... Annual Review of Microbiology journals http://www.medworm.com/rss/comments.php?id=1583722 Mon, 01 Jan 2007 05:00:00 +0100 1583722 http://www.medworm.com/index.php?rid=1583721&cid=s_37530_77_f&fid=37530&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D17506679%26dopt%3DAbstract Authors: Danhorn T, Fuqua C Plants support a diverse array of bacteria, including parasites, mutualists, and commensals on and around their roots, in the vasculature, and on aerial tissues. These microbes have a profound influence on plant health and productivity. Bacteria physically interact with surfaces to form complex multicellular and often multispecies assemblies, including biofilms and smaller aggregates. There is growing appreciation that the intensity, duration, and outcome of plant-microbe interactions are significantly influenced by the conformation of adherent microbial populations. Biofilms on different tissues have unique properties, reflecting the prevailing conditions at those sites. Attachment is required for biofilm formation, and bacteria interact with plant tissues ... Annual Review of Microbiology journals http://www.medworm.com/rss/comments.php?id=1583721 Mon, 01 Jan 2007 05:00:00 +0100 1583721 http://www.medworm.com/index.php?rid=1583720&cid=s_37530_77_f&fid=37530&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D17506680%26dopt%3DAbstract Authors: Leigh JA, Dodsworth JA A wide range of Bacteria and Archaea sense cellular 2-oxoglutarate (2OG) as an indicator of nitrogen limitation. 2OG sensor proteins are varied, but most of those studied belong to the PII superfamily. Within the PII superfamily, GlnB and GlnK represent a widespread family of homotrimeric proteins (GlnB-K) that bind and respond to 2OG and ATP. In some bacterial phyla, GlnB-K proteins are covalently modified, depending on enzymes that sense cellular glutamine as an indicator of nitrogen sufficiency. GlnB-K proteins are central clearing houses of nitrogen information and bind and modulate a variety of nitrogen assimilation regulators and enzymes. NifI(1) and NifI(2) comprise a second widespread family of PII proteins (NifI) that are heteromultimeric, respo... Annual Review of Microbiology journals http://www.medworm.com/rss/comments.php?id=1583720 Mon, 01 Jan 2007 05:00:00 +0100 1583720 http://www.medworm.com/index.php?rid=1583719&cid=s_37530_77_f&fid=37530&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D17506681%26dopt%3DAbstract Authors: Willey JM, van der Donk WA The current need for antibiotics with novel target molecules has coincided with advances in technical approaches for the structural and functional analysis of the lantibiotics, which are ribosomally synthesized peptides produced by gram-positive bacteria. These peptides have antibiotic or morphogenetic activity and are structurally defined by the presence of unusual amino acids introduced by posttranslational modification. Lantibiotics are complex polycyclic molecules formed by the dehydration of select Ser and Thr residues and the intramolecular addition of Cys thiols to the resulting unsaturated amino acids to form lanthionine and methyllanthionine bridges, respectively. Importantly, the structural and functional diversity of the lantibiotics is mu... Annual Review of Microbiology journals http://www.medworm.com/rss/comments.php?id=1583719 Mon, 01 Jan 2007 05:00:00 +0100 1583719 http://www.medworm.com/index.php?rid=1583717&cid=s_37530_77_f&fid=37530&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D17506683%26dopt%3DAbstract Authors: Walker JJ, Pace NR The endolithic environment, the pore space in rocks, is a ubiquitous microbial habitat and an interface between biology and geology. Photosynthesis-based endolithic communities inhabit the outer centimeters of rocks exposed to the surface, and offer model systems for microbial ecology, geobiology, and astrobiology. Endolithic ecosystems are among the simplest microbial ecosystems known and as such provide tractable models for testing ecological hypotheses. Such hypotheses have been difficult to test because microbial ecosystems are extraordinarily diverse. We review here recent culture-independent, ribosomal RNA-based studies that evaluate hypotheses about endolithic ecosystems, and provide insight for understanding general principles in microbial ecology. C... Annual Review of Microbiology journals http://www.medworm.com/rss/comments.php?id=1583717 Mon, 01 Jan 2007 05:00:00 +0100 1583717 http://www.medworm.com/index.php?rid=1583716&cid=s_37530_77_f&fid=37530&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D17506684%26dopt%3DAbstract Authors: Bos MP, Robert V, Tommassen J The cell envelope of gram-negative bacteria consists of two membranes, the inner and the outer membrane, that are separated by the periplasm. The outer membrane consists of phospholipids, lipopolysaccharides, integral membrane proteins, and lipoproteins. These components are synthesized in the cytoplasm or at the inner leaflet of the inner membrane and have to be transported across the inner membrane and through the periplasm to assemble eventually in the correct membrane. Recent studies in Neisseria meningitidis and Escherichia coli have led to the identification of several machineries implicated in these transport and assembly processes. PMID: 17506684 [PubMed - indexed for MEDLINE] (Source: Annual Review of Microbiology) Annual Review of Microbiology journals http://www.medworm.com/rss/comments.php?id=1583716 Mon, 01 Jan 2007 05:00:00 +0100 1583716 http://www.medworm.com/index.php?rid=1583715&cid=s_37530_77_f&fid=37530&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D17506685%26dopt%3DAbstract Authors: Chew AG, Bryant DA The use of photochemical reaction centers to convert light energy into chemical energy, chlorophototrophy, occurs in organisms belonging to only five eubacterial phyla: Cyanobacteria, Proteobacteria, Chlorobi, Chloroflexi, and Firmicutes. All chlorophototrophs synthesize two types of pigments: (a) chlorophylls and bacteriochlorophylls, which function in both light harvesting and uniquely in photochemistry; and (b) carotenoids, which function primarily as photoprotective pigments but can also participate in light harvesting. Although hundreds of carotenoids have been identified, only 12 types of chlorophylls (Chl a, b, d; divinyl-Chl a and b; and 8(1)-hydroxy-Chl a) and bacteriochlorophylls (BChl a, b, c, d, e, and g) are currently known to occur in bacteria.... Annual Review of Microbiology journals http://www.medworm.com/rss/comments.php?id=1583715 Mon, 01 Jan 2007 05:00:00 +0100 1583715 http://www.medworm.com/index.php?rid=1583713&cid=s_37530_77_f&fid=37530&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D17506687%26dopt%3DAbstract Authors: Drake HL, Horn MA The gut of the earthworm constitutes a mobile anoxic microzone to which the microorganisms of aerated soils are subjected. During gut passage, the in situ factors of the earthworm gut, which include anoxia and high concentrations of organic substrates, appear to greatly stimulate a subset of ingested soil microorganisms, including denitrifying and fermentative bacteria. The selective stimulation of ingested soil microbes by the unique microconditions of the earthworm gut (a) results in the in vivo emission of denitrification-derived dinitrogen (N(2)) and the greenhouse gas nitrous oxide (N(2)O) by the earthworm, and (b) might affect the fitness, culturability, and diversity of certain members of soil microbial biomes. These observations illustrate the impact ... Annual Review of Microbiology journals http://www.medworm.com/rss/comments.php?id=1583713 Mon, 01 Jan 2007 05:00:00 +0100 1583713 http://www.medworm.com/index.php?rid=1583712&cid=s_37530_77_f&fid=37530&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D17896875%26dopt%3DAbstract Authors: Wileman T Virus replication and virus assembly often occur in virus inclusions or virus factories that form at pericentriolar sites close to the microtubule organizing center or in specialized nuclear domains called ND10/PML bodies. Similar inclusions called aggresomes form in response to protein aggregation. Protein aggregates are toxic to cells and are transported along microtubules to aggresomes for immobilization and subsequent degradation by proteasomes and/or autophagy. The similarity between aggresomes and virus inclusions raises the possibility that viruses use aggresome pathways to concentrate cellular and viral proteins to facilitate replication and assembly. Alternatively, aggresomes may be part of an innate cellular response that recognizes virus components as fore... Annual Review of Microbiology journals http://www.medworm.com/rss/comments.php?id=1583712 Mon, 01 Jan 2007 05:00:00 +0100 1583712 http://www.medworm.com/index.php?rid=1583711&cid=s_37530_77_f&fid=37530&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D17896876%26dopt%3DAbstract Authors: Norris V, den Blaauwen T, Doi RH, Harshey RM, Janniere L, Jiménez-Sánchez A, Jin DJ, Levin PA, Mileykovskaya E, Minsky A, Misevic G, Ripoll C, Saier M, Skarstad K, Thellier M Bacterial cells contain many large, spatially extended assemblies of ions, molecules, and macromolecules, called hyperstructures, that are implicated in functions that range from DNA replication and cell division to chemotaxis and secretion. Interactions between these hyperstructures would create a level of organization intermediate between macromolecules and the cell itself. To explore this level, a taxonomy is needed. Here, we describe classification criteria based on the form of the hyperstructure and on the processes responsible for this form. These processes include those dependent on coupl... Annual Review of Microbiology journals http://www.medworm.com/rss/comments.php?id=1583711 Mon, 01 Jan 2007 05:00:00 +0100 1583711 http://www.medworm.com/index.php?rid=1583710&cid=s_37530_77_f&fid=37530&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18035606%26dopt%3DAbstract Authors: Vilchèze C, Jacobs WR Isoniazid (INH) is one of the most efficient drugs for the treatment of Mycobacterium tuberculosis infections. Despite its rather simple chemical structure, the mechanism by which INH kills M. tuberculosis is complex. A full understanding of the mechanisms of action of INH required the development of genetic tools in M. tuberculosis. Herein, we discuss the different hypotheses that have been used to describe INH action against M. tuberculosis over the past 50 years in terms of the pregenetic and genetic era. We also review the different mechanisms of INH resistance and propose what we think is the means by which INH kills M. tuberculosis. PMID: 18035606 [PubMed - indexed for MEDLINE] (Source: Annual Review of Microbiology) Annual Review of Microbiology journals http://www.medworm.com/rss/comments.php?id=1583710 Mon, 01 Jan 2007 05:00:00 +0100 1583710 http://www.medworm.com/index.php?rid=1583709&cid=s_37530_77_f&fid=37530&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18035607%26dopt%3DAbstract Authors: Hecker M, Pané-Farré J, Völker U One of the strongest and most noticeable responses of Bacillus subtilis cells to a range of stress and starvation stimuli is the dramatic induction of about 150 SigB-dependent general stress genes. The activity of SigB itself is tightly regulated by a complex signal transduction cascade with at least three main signaling pathways that respond to environmental stress, energy depletion, or low temperature. The SigB-dependent response is conserved in related gram-positive bacteria but is missing in strictly anaerobic or in some facultatively anaerobic gram-positive bacteria. It covers functions from nonspecific and multiple stress resistance to the control of virulence in pathogenic bacteria. A comprehensive understanding of this cr... Annual Review of Microbiology journals http://www.medworm.com/rss/comments.php?id=1583709 Mon, 01 Jan 2007 05:00:00 +0100 1583709 http://www.medworm.com/index.php?rid=1583708&cid=s_37530_77_f&fid=37530&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18035608%26dopt%3DAbstract Authors: Hau HH, Gralnick JA The shewanellae are aquatic microorganisms with worldwide distribution. Their hallmark features include unparalleled respiratory diversity and the capacity to thrive at low temperatures. As a genus the shewanellae are physiologically diverse, and this review provides an overview of the varied roles they serve in the environment and describes what is known about how they might survive in such extreme and harsh environments. In light of their fascinating physiology, these organisms have several biotechnological uses, from bioremediation of chlorinated compounds, radionuclides, and other environmental pollutants to energy-generating biocatalysis. The ecology and biotechnology of these organisms are intertwined, with genomics playing a key role in our understan... Annual Review of Microbiology journals http://www.medworm.com/rss/comments.php?id=1583708 Mon, 01 Jan 2007 05:00:00 +0100 1583708 http://www.medworm.com/index.php?rid=1583707&cid=s_37530_77_f&fid=37530&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18035609%26dopt%3DAbstract Authors: White AK, Metcalf WW The field of bacterial phosphorus (P) metabolism has undergone a significant transformation in the past decade owing to the elucidation of widespread and diverse pathways for the metabolism of reduced P compounds. The characterization of these pathways dramatically changes the current and narrow view of P metabolism and our understanding of the forms in which P is produced and available in the environment. In this review, recent investigations into the biochemical pathways and molecular genetics of reduced P metabolism in bacteria are discussed. Particular attention is paid to recently elucidated metabolic reactions and the genetic characterization of biosynthesis of organic reduced P compounds and to the pathways for oxidation of the inorganic reduced P c... Annual Review of Microbiology journals http://www.medworm.com/rss/comments.php?id=1583707 Mon, 01 Jan 2007 05:00:00 +0100 1583707 http://www.medworm.com/index.php?rid=1583706&cid=s_37530_77_f&fid=37530&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18035610%26dopt%3DAbstract Authors: Henriques AO, Moran CP Endospores formed by Bacillus, Clostridia, and related genera are encased in a protein shell called the coat. In many species, including B. subtilis, the coat is the outermost spore structure, and in other species, such as the pathogenic organisms B. anthracis and B. cereus, the spore is encased in an additional layer called the exosporium. Both the coat and the exosporium have roles in protection of the spore and in its environmental interactions. Assembly of both structures is a function of the mother cell, one of two cellular compartments of the developing sporangium. Studies in B. subtilis have revealed that the timing of coat protein production, the guiding role of a small group of morphogenetic proteins, and several types of posttranslational modif... Annual Review of Microbiology journals http://www.medworm.com/rss/comments.php?id=1583706 Mon, 01 Jan 2007 05:00:00 +0100 1583706 http://www.medworm.com/index.php?rid=1583725&cid=s_37530_77_f&fid=37530&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D17506675%26dopt%3DAbstract Authors: Norris V, den Blaauwen T, Cabin-Flaman A, Doi RH, Errington J, Harshey RM, Janniere L, Jimenez-Sanchez A, Jin DJ, Levin PA, Mileykovskaya E, Minsky AA, Saier M, Skarstad K, Thellier M Bacterial cells contain many large, spatially extended assemblies of ions, molecules and macromolecules, alias hyperstructures, that are implicated in functions that range from DNA replication and cell division to chemotaxis and secretion. Interactions between these hyperstructures would create a level of organization intermediate between macromolecules and the cell itself. To explore this level, a taxonomy is needed. Here, we describe classification criteria based on the form of the hyperstructure and on the processes responsible for this form. These processes include those dependent on coupled ... Annual Review of Microbiology journals http://www.medworm.com/rss/comments.php?id=1583725 Wed, 16 Aug 2006 04:00:00 +0100 1583725 http://www.medworm.com/index.php?rid=1583724&cid=s_37530_77_f&fid=37530&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D17506676%26dopt%3DAbstract Authors: Henriques AO, Moran Jr CP Endospores formed by Bacillus, Clostridia and related genera are encased in a protein shell called the coat. In many species, including B. subtilis, the coat is the outermost spore structure, while in others, as in the pathogenic organisms B. anthracis and B. cereus, the spore is encased in an additional layer called the exosporium. The coat and the exosporium function in protection of the spore, and in its environmental interactions, which include its response to germination signals. Both the coat and exosporium are assembled from components synthesized in the mother cell, one of the two cellular compartments of the developing sporangium. Studies in B. subtilis have revealed that the precise timing of coat protein expression is essential for the fide... Annual Review of Microbiology journals http://www.medworm.com/rss/comments.php?id=1583724 Wed, 16 Aug 2006 04:00:00 +0100 1583724 http://www.medworm.com/index.php?rid=1583723&cid=s_37530_77_f&fid=37530&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D17506677%26dopt%3DAbstract Authors: Hecker M, Pané-Farré J, Völker U One of the strongest and most noticeable responses of Bacillus subtilis cells to a range of stress and starvation stimuli is the dramatic induction of about 150 SigB-dependent general stress genes. The activity of SigB itself is tightly regulated by a complex signal transduction cascade with at least three main signalling pathways that respond to: environmental stress, energy depletion or low temperature. The SigB-dependent response is conserved in related Gram-positive bacteria but is missing in strictly anaerobic or in some facultatively anaerobic Gram-positive bacteria. It covers functions from a non-specific and multiple stress resistance up to the control of virulence in pathogenic bacteria. A comprehensive understanding of ... Annual Review of Microbiology journals http://www.medworm.com/rss/comments.php?id=1583723 Wed, 16 Aug 2006 04:00:00 +0100 1583723 http://www.medworm.com/index.php?rid=1583718&cid=s_37530_77_f&fid=37530&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D17506682%26dopt%3DAbstract Authors: Gralnick JA, Hau HH The shewanellae are aquatic microorganisms with worldwide distribution. Their hallmark features include unparalleled respiratory diversity and the capacity to thrive at low temperatures. As a genus the shewanellae are physiologically diverse, and this review provides an overview of the varied roles they serve in the environment and describes what is known about how they might survive in such extreme and harsh environments. In light of their fascinating physiology, these organisms have several biotechnological uses, from bioremediation of chlorinated compounds, radionuclides and other environmental pollutants to energy-generating biocatalysis. The ecology and biotechnology of these organisms is intertwined, with genomics playing a key role in understanding t... Annual Review of Microbiology journals http://www.medworm.com/rss/comments.php?id=1583718 Wed, 16 Aug 2006 04:00:00 +0100 1583718 http://www.medworm.com/index.php?rid=1583714&cid=s_37530_77_f&fid=37530&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D17506686%26dopt%3DAbstract Authors: Metcalf WW, White AK The field of bacterial phosphorus metabolism has undergone a significant transformation in the last decade due to the elucidation of widespread and diverse pathways for the metabolism of reduced phosphorus compounds. The characterization of these pathways dramatically changes the current and narrow view of P metabolism and our understanding of the forms in which P is produced and available in the environment. In this review, recent investigations into the biochemical pathways and molecular genetics of reduced P metabolism in bacteria are discussed. Particular attention is paid to recently elucidated metabolic reactions and the genetic characterization of biosynthesis of organic reduced P compounds and to the pathways for oxidation of the inorganic reduced ... Annual Review of Microbiology journals http://www.medworm.com/rss/comments.php?id=1583714 Wed, 16 Aug 2006 04:00:00 +0100 1583714 http://www.medworm.com/index.php?rid=1583762&cid=s_37530_77_f&fid=37530&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D16704339%26dopt%3DAbstract Authors: Barnhart MM, Chapman MR Curli are the major proteinaceous component of a complex extracellular matrix produced by many Enterobacteriaceae. Curli were first discovered in the late 1980s on Escherichia coli strains that caused bovine mastitis, and have since been implicated in many physiological and pathogenic processes of E. coli and Salmonella spp. Curli fibers are involved in adhesion to surfaces, cell aggregation, and biofilm formation. Curli also mediate host cell adhesion and invasion, and they are potent inducers of the host inflammatory response. The structure and biogenesis of curli are unique among bacterial fibers that have been described to date. Structurally and biochemically, curli belong to a growing class of fibers known as amyloids. Amyloid fiber formation is re... Annual Review of Microbiology journals http://www.medworm.com/rss/comments.php?id=1583762 Sun, 01 Jan 2006 05:00:00 +0100 1583762 http://www.medworm.com/index.php?rid=1583761&cid=s_37530_77_f&fid=37530&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D16704340%26dopt%3DAbstract Authors: Stolz JF, Basu P, Santini JM, Oremland RS Arsenic and selenium are readily metabolized by prokaryotes, participating in a full range of metabolic functions including assimilation, methylation, detoxification, and anaerobic respiration. Arsenic speciation and mobility is affected by microbes through oxidation/reduction reactions as part of resistance and respiratory processes. A robust arsenic cycle has been demonstrated in diverse environments. Respiratory arsenate reductases, arsenic methyltransferases, and new components in arsenic resistance have been recently described. The requirement for selenium stems primarily from its incorporation into selenocysteine and its function in selenoenzymes. Selenium oxyanions can serve as an electron acceptor in anaerobic respiration, form... Annual Review of Microbiology journals http://www.medworm.com/rss/comments.php?id=1583761 Sun, 01 Jan 2006 05:00:00 +0100 1583761 http://www.medworm.com/index.php?rid=1583760&cid=s_37530_77_f&fid=37530&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D16704341%26dopt%3DAbstract Authors: Papp-Wallace KM, Maguire ME Two areas of research have recently converged to highlight important roles for Mn(2+) in pathogenesis: the recognition that both bacterial Nramp homologs and members of LraI family of proteins are Mn(2+) transporters. Their mutation is associated with decreased virulence of various bacterial species. Thus, Mn(2+) appears to be essential for bacterial virulence. This review describes what is currently known about Mn(2+) transport in prokaryotes and how prokaryotic Mn(2+) transport is regulated. Some of the phenotypes that arise when microorganisms lack Mn(2+) are then discussed, with an emphasis on those phenotypes involving pathogenesis. The concluding section describes possible enzymatic roles for Mn(2+) that might help explain why Mn(2+) is necess... Annual Review of Microbiology journals http://www.medworm.com/rss/comments.php?id=1583760 Sun, 01 Jan 2006 05:00:00 +0100 1583760 http://www.medworm.com/index.php?rid=1583759&cid=s_37530_77_f&fid=37530&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D16704342%26dopt%3DAbstract This article summarizes recent insights from structural, biochemical, and genetic analyses of icosahedral viruses that contain single-stranded, positive-sense RNA genomes. X-ray crystallography of several viruses in this category has provided tantalizing glimpses of portions of the packaged nucleic acid, contributing crucial information on how the genome might be folded within the virion. This information combined with theoretical considerations and data from molecular approaches suggests mechanisms by which coat proteins interact with genomic RNA to shape it into a conformation that is compatible with the geometry of the virion. It appears that RNA, in addition to its function as a repository for genetic information, plays an important structural role during assembly and can on occasion o... Annual Review of Microbiology journals http://www.medworm.com/rss/comments.php?id=1583759 Sun, 01 Jan 2006 05:00:00 +0100 1583759 http://www.medworm.com/index.php?rid=1583758&cid=s_37530_77_f&fid=37530&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D16704343%26dopt%3DAbstract Authors: McLendon MK, Apicella MA, Allen LA Tularemia is a zoonosis of humans caused by infection with the facultative intracellular bacterium Francisella tularensis. Interest in F. tularensis has increased markedly in the past few years because of its potential use as an agent of bioterrorism. Five subspecies of this organism are found in the Northern hemisphere, but only F. tularensis subsp. tularensis and subsp. holarctica cause disease in humans. This review summarizes what is known about the pathogenesis of tularemia with a focus on bacterial surface components such as lipopolysaccharide and capsule as well as information obtained from the F. tularensis subsp. tularensis SCHU S4 genome. In particular, the mechanisms of action of recently identified virulence factors are discussed ... Annual Review of Microbiology journals http://www.medworm.com/rss/comments.php?id=1583758 Sun, 01 Jan 2006 05:00:00 +0100 1583758 http://www.medworm.com/index.php?rid=1583757&cid=s_37530_77_f&fid=37530&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D16704344%26dopt%3DAbstract Authors: Wall JD, Krumholz LR The dramatic decrease in solubility accompanying the reduction of U(VI) to U(IV), producing the insoluble mineral uraninite, has been viewed as a potential mechanism for sequestration of environmental uranium contamination. In the past 15 years, it has been firmly established that a variety of bacteria exhibit this reductive capacity. To obtain an understanding of the microbial metal metabolism, to develop a practical approach for the acceleration of in situ bioreduction, and to predict the long-term fate of environmental uranium, several aspects of the microbial process have been experimentally explored. This review briefly addresses the research to identify specific uranium reductases and their cellular location, competition between uranium and other ele... Annual Review of Microbiology journals http://www.medworm.com/rss/comments.php?id=1583757 Sun, 01 Jan 2006 05:00:00 +0100 1583757 http://www.medworm.com/index.php?rid=1583756&cid=s_37530_77_f&fid=37530&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D16704345%26dopt%3DAbstract Authors: Buckel W, Golding BT This review describes enzymes that contain radicals and/or catalyze reactions with radical intermediates. Because radicals irreversibly react with dioxygen, most of these enzymes occur in anaerobic bacteria and archaea. Exceptions are the families of coenzyme B(12)- and S-adenosylmethionine (SAM)-dependent radical enzymes, of which some members also occur in aerobes. Especially oxygen-sensitive radical enzymes are the glycyl radical enzymes and 2-hydroxyacyl-CoA dehydratases. The latter are activated by an ATP-dependent one-electron transfer and act via a ketyl radical anion mechanism. Related enzymes are the ATP-dependent benzoyl-CoA reductase and the ATP-independent 4-hydroxybenzoyl-CoA reductase. Ketyl radical anions may also be generated by one-electro... Annual Review of Microbiology journals http://www.medworm.com/rss/comments.php?id=1583756 Sun, 01 Jan 2006 05:00:00 +0100 1583756 http://www.medworm.com/index.php?rid=1583755&cid=s_37530_77_f&fid=37530&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D16704346%26dopt%3DAbstract Authors: Lin X, Heitman J Cryptococcus neoformans is a major cause of fungal meningoencephalitis in immunocompromised patients. Despite recent advances in the genetics and molecular biology of C. neoformans, and improved techniques for molecular epidemiology, aspects of the ecology, population structure, and mode of reproduction of this environmental pathogen remain to be established. Application of recent insights into the life cycle of C. neoformans and its different ways of engaging in sexual reproduction under laboratory conditions has just begun to affect research on the ecology and epidemiology of this human pathogenic fungus. The melding of these disparate disciplines should yield rich dividends in our understanding of the evolution of microbial pathogens, providing insights rel... Annual Review of Microbiology journals http://www.medworm.com/rss/comments.php?id=1583755 Sun, 01 Jan 2006 05:00:00 +0100 1583755 http://www.medworm.com/index.php?rid=1583754&cid=s_37530_77_f&fid=37530&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D16712436%26dopt%3DAbstract Authors: Enjuanes L, Almazán F, Sola I, Zuñiga S Infection by different coronaviruses (CoVs) causes alterations in the transcriptional and translational patterns, cell cycle, cytoskeleton, and apoptosis pathways of the host cells. In addition, CoV infection may cause inflammation, alter immune and stress responses, and modify the coagulation pathways. The balance between the up- and downregulated genes could explain the pathogenesis caused by these viruses. We review specific aspects of CoV-host interactions. CoV genome replication takes place in the cytoplasm in a membrane-protected microenvironment and may control the cell machinery by locating some of their proteins in the host cell nucleus. CoVs initiate translation by cap-dependent and cap-independent mechanisms. CoV tra... Annual Review of Microbiology journals http://www.medworm.com/rss/comments.php?id=1583754 Sun, 01 Jan 2006 05:00:00 +0100 1583754 http://www.medworm.com/index.php?rid=1583753&cid=s_37530_77_f&fid=37530&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D16719715%26dopt%3DAbstract Authors: Nohmi T In nature, microbes live under a variety of harsh conditions, such as excess DNA damage, starvation, pH shift, or high temperatures. Microbial cells respond to such stressful conditions mostly by switching global patterns of gene expression to relieve the environmental stress. The SOS response, which is induced by DNA damage, is one such global network of gene expression that plays a crucial role in balancing the genomic stability and flexibility that are necessary to adapt to harsh environments. Here, I review the roles of SOS-inducible and noninducible lesion-bypass DNA polymerases in mutagenesis induced by environmental stress, and discuss how these polymerases are coordinated for the replication of damaged chromosomes. Possible contributions of lesion-bypass DNA po... Annual Review of Microbiology journals http://www.medworm.com/rss/comments.php?id=1583753 Sun, 01 Jan 2006 05:00:00 +0100 1583753 http://www.medworm.com/index.php?rid=1583752&cid=s_37530_77_f&fid=37530&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D16719716%26dopt%3DAbstract Authors: Wagner-Döbler I, Biebl H The Roseobacter lineage is a phylogenetically coherent, physiologically heterogeneous group of alpha-Proteobacteria comprising up to 25% of marine microbial communities, especially in coastal and polar oceans, and it is the only lineage in which cultivated bacteria are closely related to environmental clones. Currently 41 subclusters are described, covering all major marine ecological niches (seawater, algal blooms, microbial mats, sediments, sea ice, marine invertebrates). Members of the Roseobacter lineage play an important role for the global carbon and sulfur cycle and the climate, since they have the trait of aerobic anoxygenic photosynthesis, oxidize the greenhouse gas carbon monoxide, and produce the climate-relevant gas dimethylsulfide thr... Annual Review of Microbiology journals http://www.medworm.com/rss/comments.php?id=1583752 Sun, 01 Jan 2006 05:00:00 +0100 1583752 http://www.medworm.com/index.php?rid=1583751&cid=s_37530_77_f&fid=37530&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D16719717%26dopt%3DAbstract Authors: Ortín J, Parra F Contrary to their host cells, many viruses contain RNA as genetic material and hence encode an RNA-dependent RNA polymerase to replicate their genomes. This review discusses the present status of our knowledge on the structure of these enzymes and the mechanisms of RNA replication. The simplest viruses encode only the catalytic subunit of the replication complex, but other viruses also contribute a variable number of ancillary factors. These and other factors provided by the host cell play roles in the specificity and affinity of template recognition and the assembly of the replication complex. Usually, these host factors are involved in protein synthesis or RNA modification in the host cell, but they play roles in remodeling RNA-RNA, RNA-protein, and pro... Annual Review of Microbiology journals http://www.medworm.com/rss/comments.php?id=1583751 Sun, 01 Jan 2006 05:00:00 +0100 1583751 http://www.medworm.com/index.php?rid=1583750&cid=s_37530_77_f&fid=37530&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D16753030%26dopt%3DAbstract Authors: Scott JR, Barnett TC Surface proteins are critical in determining the identifying characteristics of individual bacteria and their interaction with the environment. Because the structure of the cell surface is the major characteristic that distinguishes gram-positive from gram-negative bacteria, the processes used to transport and attach these proteins show significant differences between these bacterial classes. This review is intended to highlight these differences and to focus attention on areas that are ripe for further investigation. PMID: 16753030 [PubMed - indexed for MEDLINE] (Source: Annual Review of Microbiology) Annual Review of Microbiology journals http://www.medworm.com/rss/comments.php?id=1583750 Sun, 01 Jan 2006 05:00:00 +0100 1583750 http://www.medworm.com/index.php?rid=1583749&cid=s_37530_77_f&fid=37530&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D16753031%26dopt%3DAbstract Authors: Kaguni JM Escherichia coli is a model system to study the mechanism of DNA replication and its regulation during the cell cycle. One regulatory pathway ensures that initiation of DNA replication from the chromosomal origin, oriC, is synchronous and occurs at the proper time in the bacterial cell cycle. A major player in this pathway is SeqA protein and involves its ability to bind preferentially to oriC when it is hemi-methylated. The second pathway modulates DnaA activity by stimulating the hydrolysis of ATP bound to DnaA protein. The regulatory inactivation of DnaA function involves an interaction with Hda protein and the beta dimer, which functions as a sliding clamp for the replicase, DNA polymerase III holoenzyme. The datA locus represents a third mechanism, which appears... Annual Review of Microbiology journals http://www.medworm.com/rss/comments.php?id=1583749 Sun, 01 Jan 2006 05:00:00 +0100 1583749 http://www.medworm.com/index.php?rid=1583748&cid=s_37530_77_f&fid=37530&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D16753032%26dopt%3DAbstract Authors: Rappleye CA, Goldman WE Most dimorphic fungal pathogens cause respiratory disease in mammals and must therefore possess virulence mechanisms to combat and overcome host pulmonary defenses. Over the past decade, advances in genetic tools have made it possible to investigate the basis of dimorphic fungal pathogenesis at the molecular level. Gene disruptions and RNA interference have now formally demonstrated the involvement of six virulence factors: CBP, alpha-(1,3)-glucan, BAD1, SOWgp, Mep1, and urease. Additional candidate virulence-associated genes have been identified on the premise that factors necessary for pathogenicity are associated specifically with the parasitic form. This principle continues to form the foundation for genomics-based analyses to further augment the li... Annual Review of Microbiology journals http://www.medworm.com/rss/comments.php?id=1583748 Sun, 01 Jan 2006 05:00:00 +0100 1583748 http://www.medworm.com/index.php?rid=1583747&cid=s_37530_77_f&fid=37530&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D16753033%26dopt%3DAbstract Authors: Grant SR, Fisher EJ, Chang JH, Mole BM, Dangl JL Diverse gram-negative bacteria deliver effector proteins into the cells of their eukaryotic hosts using the type III secretion system. Collectively, these type III effector proteins function to optimize the host cell environment for bacterial growth. Type III effector proteins are essential for the virulence of Pseudomonas syringae, Xanthomonas spp., Ralstonia solanacearum and Erwinia species. Type III secretion systems are also found in nonpathogenic pseudomonads and in species of symbiotic nitrogen-fixing Rhizobium. We discuss the functions of type III effector proteins of plant-associated bacteria, with an emphasis on pathogens. Plant pathogens tend to carry diverse collections of type III effectors that likely share overlapp... Annual Review of Microbiology journals http://www.medworm.com/rss/comments.php?id=1583747 Sun, 01 Jan 2006 05:00:00 +0100 1583747 http://www.medworm.com/index.php?rid=1583746&cid=s_37530_77_f&fid=37530&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D16756481%26dopt%3DAbstract Authors: Lee PA, Tullman-Ercek D, Georgiou G The twin-arginine translocation (Tat) pathway is responsible for the export of folded proteins across the cytoplasmic membrane of bacteria. Substrates for the Tat pathway include redox enzymes requiring cofactor insertion in the cytoplasm, multimeric proteins that have to assemble into a complex prior to export, certain membrane proteins, and proteins whose folding is incompatible with Sec export. These proteins are involved in a diverse range of cellular activities including anaerobic metabolism, cell envelope biogenesis, metal acquisition and detoxification, and virulence. The Escherichia coli translocase consists of the TatA, TatB, and TatC proteins, but little is known about the precise sequence of events that leads to protein translocat... Annual Review of Microbiology journals http://www.medworm.com/rss/comments.php?id=1583746 Sun, 01 Jan 2006 05:00:00 +0100 1583746 http://www.medworm.com/index.php?rid=1583745&cid=s_37530_77_f&fid=37530&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D16761951%26dopt%3DAbstract Authors: Roth JR, Kugelberg E, Reams AB, Kofoid E, Andersson DI Growth under selection causes new genotypes to predominate in a population. It is difficult to determine whether selection stimulates formation of new mutations or merely allows faster growth of mutants that arise independent of selection. In the practice of microbial genetics, selection is used to detect and enumerate pre-existing mutants; stringent conditions prevent growth of the parent and allow only the pre-existing mutants to grow. Used in this way, selection detects rare mutations that cause large, easily observable phenotypic changes. In natural populations, selection is imposed on growing cells and can detect the more common mutations that cause small growth improvements. As slightly improved clones expand, they c... Annual Review of Microbiology journals http://www.medworm.com/rss/comments.php?id=1583745 Sun, 01 Jan 2006 05:00:00 +0100 1583745 http://www.medworm.com/index.php?rid=1583744&cid=s_37530_77_f&fid=37530&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D16768647%26dopt%3DAbstract Authors: Li F, Ding SW Viruses are obligate, intracellular pathogens that must manipulate and exploit host molecular mechanisms to prosper in the hostile cellular environment. Here we review the strategies used by viruses to evade the immunity controlled by 21- to 26-nt small RNAs. Viral suppressors of RNA silencing (VSRs) are encoded by genetically diverse viruses infecting plants, invertebrates, and vertebrates. VSRs target key steps in the small RNA pathways by inhibiting small RNA production, sequestering small RNAs, or preventing short- and long-distance spread of RNA silencing. However, although VSRs are required for infection, explicit data demonstrating a role of silencing suppression in virus infection are available only for a few VSRs. A subset of VSRs bind double-stranded RN... Annual Review of Microbiology journals http://www.medworm.com/rss/comments.php?id=1583744 Sun, 01 Jan 2006 05:00:00 +0100 1583744 http://www.medworm.com/index.php?rid=1583743&cid=s_37530_77_f&fid=37530&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D16771650%26dopt%3DAbstract Authors: Downs DM Metabolism encompasses the biochemical basis of life and as such spans all biological disciplines. Many decades of basic research, primarily in microbes, have resulted in extensive characterization of metabolic components and regulatory paradigms. With this basic knowledge in hand and the technologies currently available, it has become feasible to move toward an understanding of microbial metabolism as a system rather than as a collection of component parts. Insight into the system will be generated by continued efforts to rigorously define metabolic components combined with renewed efforts to discover components and connections using in vivo-driven approaches. On the tail of a detailed understanding of components and connections that comprise metabolism will come the... Annual Review of Microbiology journals http://www.medworm.com/rss/comments.php?id=1583743 Sun, 01 Jan 2006 05:00:00 +0100 1583743 http://www.medworm.com/index.php?rid=1583742&cid=s_37530_77_f&fid=37530&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D16771651%26dopt%3DAbstract Authors: Claverys JP, Prudhomme M, Martin B Bacterial transformation, a programmed mechanism for genetic exchange originally discovered in Streptococcus pneumoniae, is widespread in bacteria. It is based on the uptake and integration of exogenous DNA into the recipient genome. This review examines whether induction of competence for genetic transformation is a general response to stress in gram-positive bacteria. It compares data obtained with bacteria chosen for their different lifestyles, the soil-dweller Bacillus subtilis and the major human pathogen S. pneumoniae. The review focuses on the relationship between competence and other global responses in B. subtilis, as well as on recent evidence for competence induction in response to DNA damage or antibiotics and for the ability of S... Annual Review of Microbiology journals http://www.medworm.com/rss/comments.php?id=1583742 Sun, 01 Jan 2006 05:00:00 +0100 1583742 http://www.medworm.com/index.php?rid=1583741&cid=s_37530_77_f&fid=37530&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D16774461%26dopt%3DAbstract Authors: Maiden MC Multilocus sequence typing (MLST) was proposed in 1998 as a portable, universal, and definitive method for characterizing bacteria, using the human pathogen Neisseria meningitidis as an example. In addition to providing a standardized approach to data collection, by examining the nucleotide sequences of multiple loci encoding housekeeping genes, or fragments of them, MLST data are made freely available over the Internet to ensure that a uniform nomenclature is readily available to all those interested in categorizing bacteria. At the time of writing, over thirty MLST schemes have been published and made available on the Internet, mostly for pathogenic bacteria, although there are schemes for pathogenic fungi and some nonpathogenic bacteria. MLST data have been employ... Annual Review of Microbiology journals http://www.medworm.com/rss/comments.php?id=1583741 Sun, 01 Jan 2006 05:00:00 +0100 1583741 http://www.medworm.com/index.php?rid=1583740&cid=s_37530_77_f&fid=37530&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D16824010%26dopt%3DAbstract Authors: Lynch M The genomes of unicellular species, particularly prokaryotes, are greatly reduced in size and simplified in terms of gene structure relative to those of multicellular eukaryotes. Arguments proposed to explain this disparity include selection for metabolic efficiency and elevated rates of deletion in microbes, but the evidence in support of these hypotheses is at best equivocal. An alternative explanation based on fundamental population-genetic principles is proposed here. By increasing the mutational target sizes of associated genes, most forms of nonfunctional DNA are opposed by weak selection. Free-living microbial species have elevated effective population sizes, and the consequent reduction in the power of random genetic drift appears to be sufficient to enable nat... Annual Review of Microbiology journals http://www.medworm.com/rss/comments.php?id=1583740 Sun, 01 Jan 2006 05:00:00 +0100 1583740 http://www.medworm.com/index.php?rid=1583739&cid=s_37530_77_f&fid=37530&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D16824011%26dopt%3DAbstract Authors: Kaiser D Fortunately, I began research in 1950 when the basic concepts of microbial genetics could be explored experimentally. I began with bacteriophage lambda and tried to establish the colinearity of its linkage map with its DNA molecule. My students and I worked out the regulation of lambda repressor synthesis for the establishment and maintenance of lysogeny. We also investigated the proteins responsible for assembly of the phage head. Using cell extracts, we discovered how to package DNA inside the head in vitro. Around 1972, I began to use molecular genetics to understand the developmental biology of Myxococcus xanthus. In particular, I wanted to learn how myxococcus builds its multicellular fruiting body within which it differentiates spores. We identified two cell-to-... Annual Review of Microbiology journals http://www.medworm.com/rss/comments.php?id=1583739 Sun, 01 Jan 2006 05:00:00 +0100 1583739 http://www.medworm.com/index.php?rid=1583785&cid=s_37530_77_f&fid=37530&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D15792496%26dopt%3DAbstract Authors: Kreuzer KN The processes of DNA replication and recombination are intertwined at many different levels. In diverse systems, extensive DNA replication can be triggered by genetic recombination, with assembly of a replication complex onto a D-loop recombination intermediate. This and related pathways of replisome assembly allow the completion of DNA replication when forks initiated at a conventional replication origin fail before completing replication of the genome. In addition, the repair of double-strand breaks or gaps by homologous recombination requires at least limited DNA replication to replace the missing information. An intricate interplay between replication and recombination is also evident during the termination of bacterial DNA replication and during the induction o... Annual Review of Microbiology journals http://www.medworm.com/rss/comments.php?id=1583785 Sat, 01 Jan 2005 05:00:00 +0100 1583785 http://www.medworm.com/index.php?rid=1583784&cid=s_37530_77_f&fid=37530&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D15847602%26dopt%3DAbstract Authors: Viboud GI, Bliska JB A type III secretion system (TTSS) is encoded on a virulence plasmid that is common to three pathogenic Yersinia species: Y. enterocolitica, Y. pseudotuberculosis, and Y. pestis. Pathogenic Yersinia species require this TTSS to survive and replicate within lymphoid tissues of their animal or human hosts. A set of pathogenicity factors, including those known as Yersinia outer proteins (Yops), is exported by this system upon bacterial infection of host cells. Two translocator Yops (YopB and YopD) insert into the host plasma membrane and function to transport six effector Yops (YopO, YopH, YopM, YopT, YopJ, and YopE) into the cytosol of the host cell. Effector Yops function to counteract multiple signaling responses in the infected host cell. The signaling re... Annual Review of Microbiology journals http://www.medworm.com/rss/comments.php?id=1583784 Sat, 01 Jan 2005 05:00:00 +0100 1583784 http://www.medworm.com/index.php?rid=1583783&cid=s_37530_77_f&fid=37530&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D15877535%26dopt%3DAbstract Authors: Liti G, Louis EJ Recent sequencing efforts and experiments have advanced our understanding of genome evolution in yeasts, particularly the Saccharomyces yeasts. The ancestral genome of the Saccharomyces sensu stricto complex has been subject to both whole-genome duplication, followed by massive sequence loss and divergence, and segmental duplication. In addition the subtelomeric regions are subject to further duplications and rearrangements via ectopic exchanges. Translocations and other gross chromosomal rearrangements that break down syntenic relationships occur; however, they do not appear to be a driving force of speciation. Analysis of single genomes has been fruitful for hypothesis generation such as the whole-genome duplication, but comparative genomics between close an... Annual Review of Microbiology journals http://www.medworm.com/rss/comments.php?id=1583783 Sat, 01 Jan 2005 05:00:00 +0100 1583783 http://www.medworm.com/index.php?rid=1583782&cid=s_37530_77_f&fid=37530&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D15910274%26dopt%3DAbstract Authors: Ito K, Akiyama Y FtsH is a cytoplasmic membrane protein that has N-terminally located transmembrane segments and a main cytosolic region consisting of AAA-ATPase and Zn2+-metalloprotease domains. It forms a homo-hexamer, which is further complexed with an oligomer of the membrane-bound modulating factor HflKC. FtsH degrades a set of short-lived proteins, enabling cellular regulation at the level of protein stability. FtsH also degrades some misassembled membrane proteins, contributing to their quality maintenance. It is an energy-utilizing and processive endopeptidase with a special ability to dislocate membrane protein substrates out of the membrane, for which its own membrane-embedded nature is essential. We discuss structure-function relationships of this intriguing enzyme,... Annual Review of Microbiology journals http://www.medworm.com/rss/comments.php?id=1583782 Sat, 01 Jan 2005 05:00:00 +0100 1583782 http://www.medworm.com/index.php?rid=1583781&cid=s_37530_77_f&fid=37530&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D15910278%26dopt%3DAbstract Authors: Bennett RJ, Johnson AD Candida albicans is a normal part of the human microflora, but it is also an opportunistic fungal pathogen that causes both mucosal infections and life-threatening systemic infections. Until recently, C. albicans was thought to be asexual, existing only as an obligate diploid. However, a mating locus was identified that was homologous to those in sexually reproducing fungi, and mating of C. albicans strains was subsequently demonstrated in the laboratory. In this review, we compare and contrast the mating process in C. albicans with that of other fungi, particularly Saccharomyces cerevisiae, whose mating has been most intensively studied. Several features of the mating pathway appear unique to C. albicans, including aspects of gene regulation and cell bi... Annual Review of Microbiology journals http://www.medworm.com/rss/comments.php?id=1583781 Sat, 01 Jan 2005 05:00:00 +0100 1583781 http://www.medworm.com/index.php?rid=1583780&cid=s_37530_77_f&fid=37530&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D15910279%26dopt%3DAbstract Authors: Fuerst JA The phylum Planctomycetes of the domain Bacteria consists of budding, peptidoglycan-less organisms important for understanding the origins of complex cell organization. Their significance for cell biology lies in their possession of intracellular membrane compartmentation. All planctomycetes share a unique cell plan, in which the cell cytoplasm is divided into compartments by one or more membranes, including a major cell compartment containing the nucleoid. Of special significance is Gemmata obscuriglobus, in which the nucleoid is enveloped in two membranes to form a nuclear body that is analogous to the structure of a eukaryotic nucleus. Planctomycete compartmentation may have functional physiological roles, as in the case of anaerobic ammonium-oxidizing anammox pla... Annual Review of Microbiology journals http://www.medworm.com/rss/comments.php?id=1583780 Sat, 01 Jan 2005 05:00:00 +0100 1583780 http://www.medworm.com/index.php?rid=1583779&cid=s_37530_77_f&fid=37530&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D16153161%26dopt%3DAbstract Authors: Cohen GN My encounter with Jacques Monod has shaped my scientific career. After a short incursion in the biochemistry of strict anaerobes, and after elucidating the biosynthetic pathway leading from aspartate to threonine in Escherichia coli, I joined his laboratory. With him and Howard Rickenberg, I discovered the stereospecific permeability of galactosides and amino acids (permeases). After this intermezzo, I returned to the analysis of biosynthetic pathways and of their regulation by allosteric feedback inhibition and repression in E. coli. Among others, my studies led to the discovery of the tryptophan and methionine repressors, to the incorporation of amino acid analogues in proteins, including selenomethionine (which much later led to progress in protein crystallography)... Annual Review of Microbiology journals http://www.medworm.com/rss/comments.php?id=1583779 Sat, 01 Jan 2005 05:00:00 +0100 1583779 http://www.medworm.com/index.php?rid=1583778&cid=s_37530_77_f&fid=37530&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D16153162%26dopt%3DAbstract Authors: Harrison MJ Many microorganisms form symbioses with plants that range, on a continuous scale, from parasitic to mutualistic. Among these, the most widespread mutualistic symbiosis is the arbuscular mycorrhiza, formed between arbuscular mycorrhizal (AM) fungi and vascular flowering plants. These associations occur in terrestrial ecosystems throughout the world and have a global impact on plant phosphorus nutrition. The arbuscular mycorrhiza is an endosymbiosis in which the fungus inhabits the root cortical cells and obtains carbon provided by the plant while it transfers mineral nutrients from the soil to the cortical cells. Development of the symbiosis involves the differentiation of both symbionts to create novel symbiotic interfaces within the root cells. The aim of this rev... Annual Review of Microbiology journals http://www.medworm.com/rss/comments.php?id=1583778 Sat, 01 Jan 2005 05:00:00 +0100 1583778 http://www.medworm.com/index.php?rid=1583777&cid=s_37530_77_f&fid=37530&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D16153164%26dopt%3DAbstract Authors: Pohlschröder M, Hartmann E, Hand NJ, Dilks K, Haddad A Cells need to translocate proteins into and across hydrophobic membranes in order to interact with the extracellular environment. Although a subset of proteins are thought to spontaneously insert into lipid bilayers, translocation of most transported proteins requires additional cellular components. Such components catalyze efficient lateral transport into or across cellular membranes in prokaryotes and eukaryotes. These include, among others, the conserved YidC/Oxa1/Alb3 proteins as well as components of the Sec and the Tat pathways. Our current knowledge of the function and distribution of these components and their corresponding pathways in organisms of the three domains of life is reviewed. On the basis of this in... Annual Review of Microbiology journals http://www.medworm.com/rss/comments.php?id=1583777 Sat, 01 Jan 2005 05:00:00 +0100 1583777 http://www.medworm.com/index.php?rid=1583776&cid=s_37530_77_f&fid=37530&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D16153165%26dopt%3DAbstract Authors: Kumamoto CA, Vinces MD Candida albicans, an opportunistic fungal pathogen, causes a wide variety of human diseases such as oral thrush and disseminated candidiasis. Many aspects of C. albicans physiology have been studied during liquid growth, but in its natural environment, the gastrointestinal tract of a mammalian host, the organism associates with surfaces. Growth on a surface triggers several behaviors, such as biofilm formation, invasion, and thigmotropism, that are important for infection. Recent discoveries have identified factors that regulate these behaviors and revealed the importance of these behaviors for pathogenesis. PMID: 16153165 [PubMed - indexed for MEDLINE] (Source: Annual Review of Microbiology) Annual Review of Microbiology journals http://www.medworm.com/rss/comments.php?id=1583776 Sat, 01 Jan 2005 05:00:00 +0100 1583776 http://www.medworm.com/index.php?rid=1583775&cid=s_37530_77_f&fid=37530&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D16153167%26dopt%3DAbstract Authors: Baumann P Psyllids, whiteflies, aphids, and mealybugs are members of the suborder Sternorrhyncha and share a common property, namely the utilization of plant sap as their food source. Each of these insect groups has an obligatory association with a different prokaryotic endosymbiont, and the association is the result of a single infection followed by maternal, vertical transmission of the endosymbionts. The result of this association is the domestication of the free-living bacterium to serve the purposes of the host, namely the synthesis of essential amino acids. This domestication is probably in all cases accompanied by a major reduction in genome size. The different properties of the genomes and fragments of the genomes of these endosymbionts suggest that there are different... Annual Review of Microbiology journals http://www.medworm.com/rss/comments.php?id=1583775 Sat, 01 Jan 2005 05:00:00 +0100 1583775 http://www.medworm.com/index.php?rid=1583774&cid=s_37530_77_f&fid=37530&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D16153168%26dopt%3DAbstract Authors: Snel B, Huynen MA, Dutilh BE Genome trees are a means to capture the overwhelming amount of phylogenetic information that is present in genomes. Different formalisms have been introduced to reconstruct genome trees on the basis of various aspects of the genome. On the basis of these aspects, we separate genome trees into five classes: (a) alignment-free trees based on statistic properties of the genome, (b) gene content trees based on the presence and absence of genes, (c) trees based on chromosomal gene order, (d) trees based on average sequence similarity, and (e) phylogenomics-based genome trees. Despite their recent development, genome tree methods have already had some impact on the phylogenetic classification of bacterial species. However, their main impact so far has be... Annual Review of Microbiology journals http://www.medworm.com/rss/comments.php?id=1583774 Sat, 01 Jan 2005 05:00:00 +0100 1583774 http://www.medworm.com/index.php?rid=1583773&cid=s_37530_77_f&fid=37530&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D16153170%26dopt%3DAbstract Authors: Larrainzar E, O'Gara F, Morrissey JP When autofluorescent proteins (AFPs), such as green fluorescent protein (GFP) and Discosoma striata red fluorescent protein (DsRed), are excited with light of a specific wavelength, they emit light of a longer wavelength, without the further addition of substrates. A range of AFPs have been identified and cloned from marine organisms, and mutagenesis techniques have been employed to develop improved variant AFPs for applications in biological research. In recent years, AFP technology has become an important tool for microbiologists and microbial ecologists studying processes such as microbe-plant interactions, biosensors, biofilm formation, and horizontal gene transfer. The ability to use AFPs with differing fluorescent spectra within a sin... Annual Review of Microbiology journals http://www.medworm.com/rss/comments.php?id=1583773 Sat, 01 Jan 2005 05:00:00 +0100 1583773 http://www.medworm.com/index.php?rid=1583772&cid=s_37530_77_f&fid=37530&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D16153171%26dopt%3DAbstract Authors: Brahic M, Bureau JF, Michiels T Theiler's virus causes a persistent and demyelinating infection of the central nervous system of the mouse, which is one of the best animal models to study multiple sclerosis. This review focuses on the mechanism of persistence. The virus infects neurons for a few weeks and then shifts to white matter, where it persists in glial cells and macrophages. Oligodendrocytes are crucial host cells, as shown by the resistance to persistent infection of mice bearing myelin mutations. Two viral proteins, L and L*, contribute to persistence by interfering with host defenses. L, a small zinc-finger protein, restricts the production of interferon. L*, a unique example of a picornaviral protein translated from an overlapping open reading frame, facilitates th... Annual Review of Microbiology journals http://www.medworm.com/rss/comments.php?id=1583772 Sat, 01 Jan 2005 05:00:00 +0100 1583772 http://www.medworm.com/index.php?rid=1583771&cid=s_37530_77_f&fid=37530&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D16153172%26dopt%3DAbstract Authors: Luirink J, von Heijne G, Houben E, de Gier JW Gram-negative bacteria such as Escherichia coli are surrounded by two membranes, the inner membrane and the outer membrane. The biogenesis of most inner membrane proteins (IMPs), typical alpha-helical proteins, appears to follow a partly conserved cotranslational pathway. Targeting involves a relatively simple signal recognition particle (SRP) and SRP-receptor. Insertion of most IMPs into the membrane occurs via the Sec-translocon, which is also used for the vectorial transport of secretory proteins. Similar to eukaryotic systems, little is known about the later stages of biogenesis of IMPs, the folding and assembly in the lipid bilayer. Recently, YidC has been identified as a factor that assists in the integration, folding, and as... Annual Review of Microbiology journals http://www.medworm.com/rss/comments.php?id=1583771 Sat, 01 Jan 2005 05:00:00 +0100 1583771 http://www.medworm.com/index.php?rid=1583770&cid=s_37530_77_f&fid=37530&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D16153173%26dopt%3DAbstract Authors: Fry RC, Begley TJ, Samson LD Genome-wide studies of mRNA regulation and phenotypic responses have shown that eukaryotic cells mount a robust and multifaceted response upon exposure to DNA-damaging agents. The integration of theses studies over frameworks provided by protein-protein interactions, protein-DNA interactions, and subcellular localization information have led to the identification of networked responses to damage. Taken together, these studies illustrate that cellular protection from DNA and other macromolecular damage involves an intricate network of proteins involved in many different cellular functions, some of them expected (e.g., DNA repair and cell cycle checkpoints) but many of them unexpected (e.g., protein trafficking and degradation). This review highlight... Annual Review of Microbiology journals http://www.medworm.com/rss/comments.php?id=1583770 Sat, 01 Jan 2005 05:00:00 +0100 1583770 http://www.medworm.com/index.php?rid=1583769&cid=s_37530_77_f&fid=37530&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D16153174%26dopt%3DAbstract Authors: Majdalani N, Gottesman S RcsC, RcsB, and RcsA were first identified as a sensor kinase, a response regulator, and an auxiliary regulatory protein, respectively, regulating the genes of capsular polysaccharide synthesis. Recent advances have demonstrated that these proteins are part of a complex phosphorelay, in which phosphate travels from the histidine kinase domain in RcsC to a response regulator domain in the same protein; from there to a phosphotransfer protein, RcsD; and from there to RcsB. In addition to capsule synthesis, which requires the unstable regulatory protein RcsA, RcsB also stimulates transcription of a small RNA, RprA; the cell division gene ftsZ; and genes encoding membrane and periplasmic proteins, including the osmotically inducible genes osmB and osmC. Th... Annual Review of Microbiology journals http://www.medworm.com/rss/comments.php?id=1583769 Sat, 01 Jan 2005 05:00:00 +0100 1583769 http://www.medworm.com/index.php?rid=1583768&cid=s_37530_77_f&fid=37530&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D16153175%26dopt%3DAbstract Authors: Hinnebusch AG Cells reprogram gene expression in response to environmental changes by mobilizing transcriptional activators. The activator protein Gcn4 of the yeast Saccharomyces cerevisiae is regulated by an intricate translational control mechanism, which is the primary focus of this review, and also by the modulation of its stability in response to nutrient availability. Translation of GCN4 mRNA is derepressed in amino acid-deprived cells, leading to transcriptional induction of nearly all genes encoding amino acid biosynthetic enzymes. The trans-acting proteins that control GCN4 translation have general functions in the initiation of protein synthesis, or regulate the activities of initiation factors, so that the molecular events that induce GCN4 translation also reduce th... Annual Review of Microbiology journals http://www.medworm.com/rss/comments.php?id=1583768 Sat, 01 Jan 2005 05:00:00 +0100 1583768 http://www.medworm.com/index.php?rid=1583767&cid=s_37530_77_f&fid=37530&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D16153176%26dopt%3DAbstract Authors: Christie PJ, Atmakuri K, Krishnamoorthy V, Jakubowski S, Cascales E Type IV secretion (T4S) systems are ancestrally related to bacterial conjugation machines. These systems assemble as a translocation channel, and often also as a surface filament or protein adhesin, at the envelopes of Gram-negative and Gram-positive bacteria. These organelles mediate the transfer of DNA and protein substrates to phylogenetically diverse prokaryotic and eukaryotic target cells. Many basic features of T4S are known, including structures of machine subunits, steps of machine assembly, substrates and substrate recognition mechanisms, and cellular consequences of substrate translocation. A recent advancement also has enabled definition of the translocation route for a DNA substrate through a T4S s... Annual Review of Microbiology journals http://www.medworm.com/rss/comments.php?id=1583767 Sat, 01 Jan 2005 05:00:00 +0100 1583767 http://www.medworm.com/index.php?rid=1583766&cid=s_37530_77_f&fid=37530&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D16153177%26dopt%3DAbstract Authors: Winkler WC, Breaker RR Riboswitches are structured domains that usually reside in the noncoding regions of mRNAs, where they bind metabolites and control gene expression. Like their protein counterparts, these RNA gene control elements form highly specific binding pockets for the target metabolite and undergo allosteric changes in structure. Numerous classes of riboswitches are present in bacteria and they comprise a common and robust metabolite-sensing system. PMID: 16153177 [PubMed - indexed for MEDLINE] (Source: Annual Review of Microbiology) Annual Review of Microbiology journals http://www.medworm.com/rss/comments.php?id=1583766 Sat, 01 Jan 2005 05:00:00 +0100 1583766 http://www.medworm.com/index.php?rid=1583765&cid=s_37530_77_f&fid=37530&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D16153178%26dopt%3DAbstract Authors: Young DM, Parke D, Ornston LN The genetic and physiological properties of Acinetobacter baylyi strain ADP1 make it an inviting subject for investigation of the properties underlying its nutritional versatility. The organism possesses a relatively small genome in which genes for most catabolic functions are clustered in several genetic islands that, unlike pathogenicity islands, give little evidence of horizontal transfer. Coupling mutagenic polymerase chain reaction to natural transformation provides insight into how structure influences function in transporters, transcriptional regulators, and enzymes. With appropriate selection, mutants in which such molecules have acquired novel function may be obtained. The extraordinary competence of A. baylyi for natural transformation a... Annual Review of Microbiology journals http://www.medworm.com/rss/comments.php?id=1583765 Sat, 01 Jan 2005 05:00:00 +0100 1583765 http://www.medworm.com/index.php?rid=1583764&cid=s_37530_77_f&fid=37530&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D16153179%26dopt%3DAbstract Authors: Parrish CR, Kawaoka Y Transfer of viruses between hosts to create a new self-sustaining epidemic is rare; however, those new viruses can cause severe outbreaks. Examples of such viruses include three pandemic human influenza A viruses and canine parvovirus in dogs. In each case one virus made the original transfer and spread worldwide, and then further adaptation resulted in the emergence of variants worldwide. For the influenza viruses several changes were required for growth and spread between humans, and the emergence of human H2N2 and H3N2 strains in 1957 and 1968 involved the acquisition of three or two new genomic segments, respectively. Adaptation to humans involved several viral genes including the hemagglutinin, the neuraminidase, and the replication proteins. The can... Annual Review of Microbiology journals http://www.medworm.com/rss/comments.php?id=1583764 Sat, 01 Jan 2005 05:00:00 +0100 1583764 http://www.medworm.com/index.php?rid=1583763&cid=s_37530_77_f&fid=37530&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D16153180%26dopt%3DAbstract Authors: Kew OM, Sutter RW, de Gourville EM, Dowdle WR, Pallansch MA As the global eradication of wild poliovirus nears, the World Health Organization (WHO) is addressing challenges unprecedented in public health. The live, attenuated oral poliovirus vaccine (OPV), used for more than four decades to interrupt poliovirus transmission, and the vaccine of choice for developing countries, is genetically unstable. Reversion of the small number of substitutions conferring the attenuated phenotype frequently occurs during OPV replication in humans and is the underlying cause of the rare cases of vaccine-associated paralytic poliomyelitis (VAPP) in OPV recipients and their close contacts. Whereas VAPP has long been recognized, two other adverse events have been identified more recently: (a) lo... Annual Review of Microbiology journals http://www.medworm.com/rss/comments.php?id=1583763 Sat, 01 Jan 2005 05:00:00 +0100 1583763 http://www.medworm.com/index.php?rid=1583794&cid=s_37530_77_f&fid=37530&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D15487943%26dopt%3DAbstract Authors: Shoukry NH, Cawthon AG, Walker CM The hepatitis C virus (HCV) infects approximately three percent of the world's population. Some individuals resolve the infection spontaneously, but the majority develop persistent viremia that often causes progressive liver disease. There is an emerging consensus that cellular immune responses are essential for spontaneous resolution of acute hepatitis C and long-term protection from persistent infection. This review focuses on the recent advances in understanding mechanisms of protective immunity and why they fail in most infected individuals. The distinct yet complementary role of CD4+ and CD8+ T lymphocytes in this process is highlighted. PMID: 15487943 [PubMed - indexed for MEDLINE] (Source: Annual Review of Microbiology) Annual Review of Microbiology journals http://www.medworm.com/rss/comments.php?id=1583794 Thu, 01 Jan 2004 05:00:00 +0100 1583794 http://www.medworm.com/index.php?rid=1583793&cid=s_37530_77_f&fid=37530&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D15487944%26dopt%3DAbstract Authors: Peñalva MA, Arst HN All microorganisms must adapt to the pH of their environment. One aspect of this adaptation, particularly important for organisms that grow over a wide pH range, is the ability to express appropriately genes whose roles ultimately involve functions at the cell surface or in the environment. Genes encoding permeases, secreted enzymes, enzymes involved in synthesis of exported metabolites such as toxins and antibiotics, and probably enzymes modifying secreted proteins posttranslationally all fall into this category. Here we discuss the most recent findings on the transcriptional regulatory system in fungi that enables such genes to be expressed only when the ambient pH is conducive to their ultimate functions. The intriguing issue of how pH is sensed and... Annual Review of Microbiology journals http://www.medworm.com/rss/comments.php?id=1583793 Thu, 01 Jan 2004 05:00:00 +0100 1583793