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 'Trends in Microbiology' source. Fri, 19 Mar 2010 17:36:46 +0100 http://www.medworm.com/index.php?rid=3347328&cid=s_36143_77_f&fid=36143&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20207544%26dopt%3DAbstract This article provides a perspective on the current status of drug therapy for invasive fungal diseases, together with priorities for the future development of novel compounds. Key opportunities for new drugs include production of orally bioavailable agents for the treatment of invasive aspergillosis, invasive candidiasis, cryptococcal meningitis and mucosal and urinary Candida infections. Orally bioavailable agents for the treatment of chronic pulmonary and allergic aspergillosis are also required, as well as new potent drugs against a range of medically important moulds. Antifungal resistance is a problem in certain contexts, but is generally less of a problem than bacterial infections. Earlier and more complete mycological diagnosis and improvements in underlying risk estimation will imp... Trends in Microbiology journals http://www.medworm.com/rss/comments.php?id=3347328 Fri, 05 Mar 2010 00:00:00 +0100 3347328 http://www.medworm.com/index.php?rid=3336222&cid=s_36143_77_f&fid=36143&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20202845%26dopt%3DAbstract Authors: Hakami RM, Ruthel G, Stahl AM, Bavari S Owing in part to recently heightened concern over bioterrorism, interest in the mechanism of action of botulinum neurotoxin (BoNT) and development of effective therapeutic strategies has dramatically increased. The emergence of BoNT as an effective treatment for a variety of neurological disorders and its growing use in the cosmetic industry have also increased interest in developing effective countermeasures. Although recent attempts to create effective vaccines appear promising, the multitude of clinical and cosmetic uses of BoNT make mass vaccination against the toxin undesirable and impractical, leading to intensified efforts to develop effective therapeutics to combat large-scale intoxications. In this review, we examine the relevan... Trends in Microbiology journals http://www.medworm.com/rss/comments.php?id=3336222 Tue, 02 Mar 2010 00:00:00 +0100 3336222 http://www.medworm.com/index.php?rid=3336221&cid=s_36143_77_f&fid=36143&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20202846%26dopt%3DAbstract Authors: Chen Y, Murrell JC The application of metagenomics, the culture-independent capture and subsequent analysis of genomic DNA from the environment, has greatly expanded our knowledge of the diversity of microbes and microbial protein families; however, the metabolic functions of many microorganisms remain largely unknown. DNA stable-isotope probing (DNA-SIP) is a recently developed method in which the incorporation of stable isotope from a labelled substrate is used to identify the function of microorganisms in the environment. The technique has now been used in conjunction with metagenomics to establish links between microbial identity and particular metabolic functions. The combination of DNA-SIP and metagenomics not only permits the detection of rare low-abundance species from... Trends in Microbiology journals http://www.medworm.com/rss/comments.php?id=3336221 Tue, 02 Mar 2010 00:00:00 +0100 3336221 http://www.medworm.com/index.php?rid=3336220&cid=s_36143_77_f&fid=36143&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20202847%26dopt%3DAbstract Authors: Pflüger-Grau K, Görke B In addition to the sugar phosphotransferase system (sugar PTS) dedicated to carbohydrate uptake, many Gram-negative bacteria possess a so-called nitrogen PTS (PTS(Ntr)). Although fulfilling very different functions, both systems can communicate with each other by phosphate exchange. PTS(Ntr) regulates diverse processes implicated in metabolism of nitrogen and carbon, and is essential for virulence in some bacteria. Additionally, it plays a role in potassium homeostasis by regulating the expression and activity of a high- and a low-affinity K(+) transporter, respectively. In this article, we review recent advances in the understanding of the regulatory roles of PTS(Ntr) in various organisms. PMID: 20202847 [PubMed - as supplied by publisher... Trends in Microbiology journals http://www.medworm.com/rss/comments.php?id=3336220 Tue, 02 Mar 2010 00:00:00 +0100 3336220 http://www.medworm.com/index.php?rid=3303253&cid=s_36143_77_f&fid=36143&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20176487%26dopt%3DAbstract Authors: Johnson EM In the past three years, remarkable discoveries have added three new human polyomaviruses (KI virus (KIV), WU virus (WUV) and Merkel cell virus (MCV)) to a class that previously had only two disease-causing members (BK virus (BKV) and JC virus (JCV)) identified. Two monkey polyomaviruses, simian virus (SV)40 and B-cell lymphotropic polyomavirus (LPV) are also present in humans. KIV and WUV lack the agnoprotein coding sequence and regulatory micro (mi)RNA clusters of BKV, JCV and SV40. MCV lacks the agnoprotein sequence but generates miRNAs. KIV, WUV and MCV are all widespread in humans. Although they have distinctive tissue tropisms, all these viruses are probably acquired in childhood. Of these viruses, only MCV has thus far been strongly linked to cancer. Marshall... Trends in Microbiology journals http://www.medworm.com/rss/comments.php?id=3303253 Sat, 20 Feb 2010 00:00:00 +0100 3303253 http://www.medworm.com/index.php?rid=3291446&cid=s_36143_77_f&fid=36143&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20167493%26dopt%3DAbstract Authors: Tucker NP, Le Brun NE, Dixon R, Hutchings MI Nitric oxide (NO) is a toxic, free radical gas with diverse biological roles in eukaryotes and bacteria, being involved in signalling, vasodilation, blood clotting and immunity and as an intermediate in microbial denitrification. Several bacterial transcriptional regulators sense this molecule and regulate the expression of genes involved in both NO detoxification and NO damage repair. However, a recently discovered NO sensing repressor, named NsrR, has gained attention because of its suggested role as a global regulator of the bacterial NO stress response. Recent advances in biochemical and transcriptomic studies of NsrR make it timely to review the current evidence for NsrR as a global regulator and to speculate on the recent cont... Trends in Microbiology journals http://www.medworm.com/rss/comments.php?id=3291446 Tue, 16 Feb 2010 00:00:00 +0100 3291446 http://www.medworm.com/index.php?rid=3186816&cid=s_36143_77_f&fid=36143&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20083406%26dopt%3DAbstract Authors: Kent BN, Bordenstein SR The discovery of an extraordinarily high level of mobile elements in the genome of Wolbachia, a widespread arthropod and nematode endosymbiont, suggests that this bacterium could be an excellent model for assessing the evolution and function of mobile DNA in specialized bacteria. In this paper, we discuss how studies on the temperate bacteriophage WO of Wolbachia have revealed unexpected levels of genomic flux and are challenging previously held views about the clonality of obligate intracellular bacteria. We also discuss the roles this phage might play in the Wolbachia-arthropod symbiosis and infer how this research can be translated to combating human diseases vectored by arthropods. We expect that this temperate phage will be a preeminent model syste... Trends in Microbiology journals http://www.medworm.com/rss/comments.php?id=3186816 Sat, 16 Jan 2010 00:00:00 +0100 3186816 http://www.medworm.com/index.php?rid=3186817&cid=s_36143_77_f&fid=36143&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20080407%26dopt%3DAbstract Authors: Harrison PW, Lower RP, Kim NK, Young JP In addition to the main chromosome, approximately one in ten bacterial genomes have a 'second chromosome' or 'megaplasmid'. Here, we propose that these represent a single class of elements that have a distinct and consistent set of properties, and suggest the term 'chromid' to distinguish them from both chromosomes and plasmids. Chromids carry some core genes, and their nucleotide composition and codon usage are very similar to those of the chromosomes they are associated with. By contrast, they have plasmid replication and partitioning systems and the majority of their genes confer accessory functions. Chromids seem particularly rich in genus-specific genes and appear to be 'reinvented' at the origin of a new genus. PMID: 20080407 [... Trends in Microbiology journals http://www.medworm.com/rss/comments.php?id=3186817 Fri, 15 Jan 2010 00:00:00 +0100 3186817 http://www.medworm.com/index.php?rid=3179191&cid=s_36143_77_f&fid=36143&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20071175%26dopt%3DAbstract Authors: Feng Y, Zhang H, Ma Y, Gao GF Streptococcus suis is recognized as a major swine pathogen and an emerging zoonotic agent. Two large-scale outbreaks of severe S. suis epidemics occurred in China in 1998 and 2005 that posed serious concerns to public health and challenged the conventional conception that opportunistic infections of S. suis serotype 2 (SS2) in humans were only sporadic cases. An extensive, collaborative study on Chinese SS2 variants, which exhibit strong invasiveness and high pathogenicity, has resulted in the description of a new disease form of streptococcal toxic shock syndrome (STSS) and a putative pathogenicity island (termed 89K). The abbreviation of STSS is used for the severe disease caused by both Staphylococci and Streptococci. The main virulence factors... Trends in Microbiology journals http://www.medworm.com/rss/comments.php?id=3179191 Mon, 11 Jan 2010 00:00:00 +0100 3179191 http://www.medworm.com/index.php?rid=3164511&cid=s_36143_77_f&fid=36143&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20060721%26dopt%3DAbstract Authors: Vollmer W, Seligman SJ Peptidoglycan forms a net-like sacculus made of glycan strands crosslinked by peptides. The length of the glycan strands and the degree of crosslinkage vary with bacterial species, strains and growth conditions. Several models for the three-dimensional architecture of peptidoglycan have been proposed, some of which have been tested experimentally. The new data support a layered model in Gram-negative bacteria, and a more elaborate peptidoglycan architecture, with bands made of coiled bundles of glycan strands, in the rod-shaped Bacillus subtilis. However, many questions remain unanswered and, therefore, more data and more models are required to decipher the complex cell wall architecture in bacteria. PMID: 20060721 [PubMed - as supplied by publisher]... Trends in Microbiology journals http://www.medworm.com/rss/comments.php?id=3164511 Thu, 07 Jan 2010 00:00:00 +0100 3164511 http://www.medworm.com/index.php?rid=3164509&cid=s_36143_77_f&fid=36143&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20060722%26dopt%3DAbstract Authors: Niederweis M, Danilchanka O, Huff J, Hoffmann C, Engelhardt H The cell wall is a major virulence factor of Mycobacterium tuberculosis and contributes to its intrinsic drug resistance. Recently, cryo-electron microscopy showed that mycobacterial cell wall lipids form an unusual outer membrane. Identification of the components of the uptake and secretion machinery across this membrane will be crucial for understanding the physiology and pathogenicity of M. tuberculosis and for the development of better anti-tuberculosis drugs. Although the genome of M. tuberculosis appears to encode over 100 putative outer membrane proteins, only a few have been identified and characterized. Here, we summarize the current knowledge on the structure of the mycobacterial outer membrane and its kno... Trends in Microbiology journals http://www.medworm.com/rss/comments.php?id=3164509 Thu, 07 Jan 2010 00:00:00 +0100 3164509 http://www.medworm.com/index.php?rid=3164507&cid=s_36143_77_f&fid=36143&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20060723%26dopt%3DAbstract Authors: Medjahed H, Gaillard JL, Reyrat JM Mycobacterium abscessus, a relative of Koch's bacillus (the bacterium that causes tuberculosis), has recently emerged as the cause of an increasing number of both community- and hospital-acquired infections in humans; it also constitutes a serious threat for cystic fibrosis patients. This situation is worsened by its exceptionally high natural and acquired antibiotic resistance that complicates treatment. Although a rapid grower, it shares some traits with Koch's bacillus, including the ability to induce a persistent lung disease associated with caseous lesions, a landmark of Mycobacterium tuberculosis infection. Its genome sequence and microarrays are now available, and efficient genetic tools have recently been developed. Here we consider t... Trends in Microbiology journals http://www.medworm.com/rss/comments.php?id=3164507 Thu, 07 Jan 2010 00:00:00 +0100 3164507 http://www.medworm.com/index.php?rid=3164513&cid=s_36143_77_f&fid=36143&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20060299%26dopt%3DAbstract Authors: Decho AW, Norman RS, Visscher PT Much laboratory-based information exists on quorum sensing, a type of bacterial cell-to-cell communication that depends upon exchanges of molecular signals between neighboring cells. However, little is known about how this and other microbial sensing systems operate in nature. Geochemical and biological modifications of signals probably occur in extracellular environments, and these could disrupt intended communication if signals are no longer recognized. However, as we discuss here, signal alterations might result in other outcomes: if a modified signal is able to interact with a different receptor then further environmental information can be gained by the receiving cells. We also postulate that quorum sensing occurs within cell clusters, whe... Trends in Microbiology journals http://www.medworm.com/rss/comments.php?id=3164513 Wed, 06 Jan 2010 00:00:00 +0100 3164513 http://www.medworm.com/index.php?rid=3164512&cid=s_36143_77_f&fid=36143&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20060300%26dopt%3DAbstract This article describes personal experiences of research-led teaching at Manchester Metropolitan University (UK) which have been used successfully to encourage creativity and other employability skills in both large and smaller classroom settings, and through individual student project work. PMID: 20060300 [PubMed - as supplied by publisher] (Source: Trends in Microbiology) Trends in Microbiology journals http://www.medworm.com/rss/comments.php?id=3164512 Wed, 06 Jan 2010 00:00:00 +0100 3164512 http://www.medworm.com/index.php?rid=3142913&cid=s_36143_77_f&fid=36143&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20045332%26dopt%3DAbstract Authors: Raina JB, Dinsdale EA, Willis BL, Bourne DG Dimethylsulfoniopropionate (DMSP) and dimethylsulfide (DMS) are key compounds in the global sulfur cycle. Moreover, DMS is particularly important in climate regulation owing to its role in cloud formation. Reef building corals are major contributors to the production of these two compounds and also form diverse and complex associations with bacteria, which are known to play a crucial role in the degradation of DMSP and DMS. Here, we highlight an extensive overlap between bacterial species implicated in DMSP/DMS degradation and those associated with corals, leading to the hypothesis that these two compounds play a major role in structuring coral-associated bacterial communities, with important consequences for coral health and the res... Trends in Microbiology journals http://www.medworm.com/rss/comments.php?id=3142913 Wed, 30 Dec 2009 00:00:00 +0100 3142913 http://www.medworm.com/index.php?rid=3130134&cid=s_36143_77_f&fid=36143&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20036125%26dopt%3DAbstract Authors: Sandal I, Inzana TJ Histophilus somni is an obligate inhabitant of the respiratory and genital mucosal surfaces of bovines and ovines. An individual strain can be a primary pathogen, an opportunistic pathogen, or a commensal, but can also move between these classifications if introduced into an appropriate site (e.g. the lungs) under conditions that favor bacterial persistence. H. somni is one of the bacterial agents responsible for bovine respiratory disease complex and can also cause a variety of systemic diseases in cattle and sheep. Isolates from disease sites, such as the lungs, heart, and brain, express a wide array of virulence factors (including biofilm formation) designed to evade host defense mechanisms. By contrast, some isolates from the healthy genital tract often... Trends in Microbiology journals http://www.medworm.com/rss/comments.php?id=3130134 Wed, 23 Dec 2009 00:00:00 +0100 3130134 http://www.medworm.com/index.php?rid=3119615&cid=s_36143_77_f&fid=36143&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20031415%26dopt%3DAbstract Authors: Jambo KC, Sepako E, Heyderman RS, Gordon SB Pneumococcal pneumonia is a life-threatening disease with high mortality and morbidity among children under 5 years of age, the elderly and immunocompromised individuals worldwide. Protection against pneumococcal pneumonia relies on successful regulation of colonisation in the nasopharynx and a brisk alveolar macrophage-mediated immune response in the lung. Therefore, enhancing pulmonary mucosal immunity (which includes a combination of innate, humoral and cell-mediated immunity) through mucosal vaccination might be the key to prevention of pneumococcal infection. Current challenges include a lack of information in humans on mucosal immunity against pneumococci and a lack of suitable adjuvants for new vaccines. Data from mouse models... Trends in Microbiology journals http://www.medworm.com/rss/comments.php?id=3119615 Mon, 21 Dec 2009 00:00:00 +0100 3119615 http://www.medworm.com/index.php?rid=3067558&cid=s_36143_77_f&fid=36143&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19962898%26dopt%3DAbstract Authors: Al-Khodor S, Price CT, Kalia A, Abu Kwaik Y The ankyrin repeat (ANK) is the most common protein-protein interaction motif in nature, and is predominantly found in eukaryotic proteins. Genome sequencing of various pathogenic or symbiotic bacteria and eukaryotic viruses has identified numerous genes encoding ANK-containing proteins that are proposed to have been acquired from eukaryotes by horizontal gene transfer. However, the recent discovery of additional ANK-containing proteins encoded in the genomes of archaea and free-living bacteria suggests either a more ancient origin of the ANK motif or multiple convergent evolution events. Many bacterial pathogens employ various types of secretion systems to deliver ANK-containing proteins into eukaryotic cells, where they mimic or ma... Trends in Microbiology journals http://www.medworm.com/rss/comments.php?id=3067558 Thu, 03 Dec 2009 00:00:00 +0100 3067558 http://www.medworm.com/index.php?rid=3067557&cid=s_36143_77_f&fid=36143&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19962899%26dopt%3DAbstract Authors: Weerdenburg EM, Peters PJ, van der Wel NN CD8(+) T cells are activated upon presentation of antigens from the cytosol. Therefore, it was unclear how pathogenic mycobacteria could prime this type of lymphocyte, given that these microbes were thought to remain in phagosomes and, hence, be shielded from the host cytosol. Recently, it was shown that some mycobacteria can enter the cytosol through translocation from phagolysosomes, providing a direct mechanism for CD8(+) T cell priming. However, this mechanism might not apply to other mycobacteria, which do not appear to be able to enter the cytosol. Here, we discuss the different hypotheses to explain the induction of CD8(+) T cell responses in mycobacterial infections. PMID: 19962899 [PubMed - as supplied by publisher] (Sourc... Trends in Microbiology journals http://www.medworm.com/rss/comments.php?id=3067557 Thu, 03 Dec 2009 00:00:00 +0100 3067557 http://www.medworm.com/index.php?rid=3061706&cid=s_36143_77_f&fid=36143&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19959363%26dopt%3DAbstract Authors: Bathe M, Chang F Cytokinesis, the final stage of the cell division cycle, requires the proper placement, assembly and contraction of an actomyosin-based contractile ring. Conserved sets of cytokinesis proteins and pathways have now been identified and characterized functionally. Additionally, fluorescent protein fusion technology enables quantitative high-resolution imaging of protein dynamics in living cells. For these reasons, the study of cytokinesis is now ripe for quantitative, systems-level approaches. Here, we review our current understanding of the molecular mechanisms of contractile ring dynamics in the model organism Schizosaccharomyces pombe (fission yeast), focusing on recent examples that illustrate a synergistic integration of quantitative experimental data with ... Trends in Microbiology journals http://www.medworm.com/rss/comments.php?id=3061706 Tue, 01 Dec 2009 00:00:00 +0100 3061706 http://www.medworm.com/index.php?rid=3040413&cid=s_36143_77_f&fid=36143&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19944609%26dopt%3DAbstract Authors: Torgerson PR, Torgerson DJ Bovine tuberculosis (bTB) in UK cattle is increasing rapidly. Consequently, the UK Government is spending escalating sums of money in attempts at disease control. We propose that bTB control in cattle is irrelevant as a public health policy. In the UK, cattle-to-human transmission is negligible. Aerosol transmission, the only probable route of human acquisition, occurs at inconsequential levels when milk is pasteurised, even when bTB is highly endemic in cattle. Furthermore, there is little evidence for a positive cost benefit in terms of animal health of bTB control. Such evidence is required; otherwise, there is little justification for the large sums of public money spent on bTB control in the UK. PMID: 19944609 [PubMed - as supplied by publis... Trends in Microbiology journals http://www.medworm.com/rss/comments.php?id=3040413 Wed, 25 Nov 2009 00:00:00 +0100 3040413 http://www.medworm.com/index.php?rid=3036613&cid=s_36143_77_f&fid=36143&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19942436%26dopt%3DAbstract Authors: Safa A, Nair GB, Kong RY Vibrio cholerae typically contains a prophage that carries the genes encoding the cholera toxin, which is responsible for the major clinical symptoms of the disease. In recent years, new pathogenic variants of V. cholerae have emerged and spread throughout many Asian and African countries. These variants display a mixture of phenotypic and genotypic traits from the two main biotypes (known as 'classical' and 'El Tor'), suggesting that they are genetic hybrids. Classical and El Tor biotypes have been the most epidemiologically successful cholera strains during the past century, and it is believed that the new variants (which we call here 'atypical El Tor') are likely to develop successfully in a manner similar to these biotypes. Here, we describe recent... Trends in Microbiology journals http://www.medworm.com/rss/comments.php?id=3036613 Tue, 24 Nov 2009 00:00:00 +0100 3036613 http://www.medworm.com/index.php?rid=3036612&cid=s_36143_77_f&fid=36143&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19942437%26dopt%3DAbstract Authors: Kristensen DM, Mushegian AR, Dolja VV, Koonin EV Metagenomic analysis of viruses suggests novel patterns of evolution, changes the existing ideas of the composition of the virus world and reveals novel groups of viruses and virus-like agents. The gene composition of the marine DNA virome is dramatically different from that of known bacteriophages. The virome is dominated by rare genes, many of which might be contained within virus-like entities such as gene transfer agents. Analysis of marine metagenomes thought to consist mostly of bacterial genes revealed a variety of sequences homologous to conserved genes of eukaryotic nucleocytoplasmic large DNA viruses, resulting in the discovery of diverse members of previously undersampled groups and suggesting the existence of new cla... Trends in Microbiology journals http://www.medworm.com/rss/comments.php?id=3036612 Tue, 24 Nov 2009 00:00:00 +0100 3036612 http://www.medworm.com/index.php?rid=3036611&cid=s_36143_77_f&fid=36143&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19942438%26dopt%3DAbstract Authors: Anderson JK, Smith TG, Hoover TR The flagellum, a rotary engine required for motility in many bacteria, plays key roles in gene expression. It has been known for some time that flagellar substructures serve as checkpoints that coordinate flagellar gene expression with assembly. Less well understood, however, are other more global effects on gene expression. For instance, the flagellum acts as a 'wetness' sensor in Salmonella typhimurium, and as a mechanosensor in other bacteria. Additionally, it has been implicated in a variety of bacterial processes, including biofilm formation, pathogenesis and symbiosis. Although for many of these processes it might be simply that motility is required, in other cases it seems that the flagellum plays an underappreciated role in regulating g... Trends in Microbiology journals http://www.medworm.com/rss/comments.php?id=3036611 Tue, 24 Nov 2009 00:00:00 +0100 3036611 http://www.medworm.com/index.php?rid=2978103&cid=s_36143_77_f&fid=36143&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19896852%26dopt%3DAbstract Authors: Schoenfeld T, Liles M, Wommack KE, Polson SW, Godiska R, Mead D The enzymes of bacteriophages and other viruses have been essential research tools since the first days of molecular biology. However, the current repertoire of viral enzymes only hints at their overall potential. The most commonly used enzymes are derived from a surprisingly small number of cultivated viruses, which is remarkable considering the extreme abundance and diversity of viruses revealed over the past decade by metagenomic analysis. To access the treasure trove of enzymes hidden in the global virosphere and develop them for research, therapeutic and diagnostic uses, improvements are needed in our ability to rapidly and efficiently discover, express and characterize viral genes to produce useful proteins.... Trends in Microbiology journals http://www.medworm.com/rss/comments.php?id=2978103 Thu, 05 Nov 2009 00:00:00 +0100 2978103 http://www.medworm.com/index.php?rid=2935593&cid=s_36143_77_f&fid=36143&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19853456%26dopt%3DAbstract Authors: Cozzone AJ The resistance of pathogenic bacteria to current antibiotics has become a crucial public health problem. To combat this resistance, there is a constant need for antibacterial drugs with new modes of action on therapeutic targets. Recent data have shown that a variety of cellular processes essential for bacterial survival and virulence are regulated by the phosphorylation of certain endogenous proteins catalyzed by specific tyrosine kinases. In this article, I highlight a selection of recent findings that confirm the central role of protein tyrosine phosphorylation in the control of bacterial physiology. Based on this knowledge, potential applications in the discovery of novel antibiotics are proposed. PMID: 19853456 [PubMed - as supplied by publisher] (Source: T... Trends in Microbiology journals http://www.medworm.com/rss/comments.php?id=2935593 Wed, 21 Oct 2009 00:00:00 +0100 2935593 http://www.medworm.com/index.php?rid=2935591&cid=s_36143_77_f&fid=36143&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19853457%26dopt%3DAbstract Authors: Kaltenpoth M Mutualistic microorganisms are well known to play a key role in providing nutrients for successful growth and reproduction in many insects. Several recent studies indicate that they can be equally important for the protection of the host and its nutritional resources against pathogen attack. In particular, different actinobacteria have been found to defend ants, beetles and wasps against detrimental microorganisms by producing antibiotics. The extraordinary abilities of actinobacteria to exploit a wide variety of carbon and nitrogen sources and their extensive repertoire of secondary metabolites probably predispose this group to engage in protective symbioses. Defensive mutualisms with actinobacteria might constitute a general and widespread theme in the ecology a... Trends in Microbiology journals http://www.medworm.com/rss/comments.php?id=2935591 Wed, 21 Oct 2009 00:00:00 +0100 2935591 http://www.medworm.com/index.php?rid=2902151&cid=s_36143_77_f&fid=36143&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19833519%26dopt%3DAbstract Authors: Harding MW, Marques LL, Howard RJ, Olson ME The discovery of biofilm formation in bacteria and yeasts has led to a better understanding of microbial ecology and to new insights into the mechanisms of virulence and persistence of pathogenic microorganisms. However, it is generally assumed that filamentous fungi, some of which have a significant impact on our health or our economy, do not form biofilms. In contrast to this assumption, here we discuss recent findings supporting the hypothesis that surface-associated filamentous fungi can form biofilms. Based on these findings and on previous models for bacterial and yeast systems, we propose preliminary criteria and a model for biofilm formation by filamentous fungi. PMID: 19833519 [PubMed - as supplied by publisher] (Source:... Trends in Microbiology journals http://www.medworm.com/rss/comments.php?id=2902151 Mon, 12 Oct 2009 23:00:00 +0100 2902151 http://www.medworm.com/index.php?rid=2902153&cid=s_36143_77_f&fid=36143&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19828316%26dopt%3DAbstract Authors: Boss IW, Plaisance KB, Renne R MicroRNAs (miRNAs) are short RNAs of about 22 nucleotides in length that post-transcriptionally regulate gene expression by binding to 3' untranslated regions of mRNAs, thereby inducing translational silencing. Recently, more than 140 miRNAs have been identified in the genomes of herpesviruses. Deciphering their role in viral biology requires the identification of target genes, a challenging task because miRNAs require only limited complementarity. The subject of this review will be the herpesvirus miRNAs and their respective target genes that have been determined experimentally to date. These miRNAs regulate fundamental cellular processes including immunity, angiogenesis, apoptosis, and key steps in the herpesvirus life cycle, latency and the sw... Trends in Microbiology journals http://www.medworm.com/rss/comments.php?id=2902153 Sun, 11 Oct 2009 23:00:00 +0100 2902153 http://www.medworm.com/index.php?rid=2902152&cid=s_36143_77_f&fid=36143&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19828317%26dopt%3DAbstract Authors: Gast RJ, Sanders RW, Caron DA Protistan species are found in almost every environment on our planet, and have adapted in many ways to survive and thrive under dramatically different conditions. Some of the most diverse adaptations involve symbiotic relationships with prokaryotes. Described symbioses primarily involve heterotrophic protists, including ciliates, Rhizaria (amoebae, foraminifera, radiolaria) and flagellate taxa. Recently there has been an increase in reports of environmental isolates that represent novel associations, which suggest that the symbioses are probably more widespread than conventionally thought. Future work will need to explore the function, abundance and distribution of what have been considered rare or unusual interactions. PMID: 19828317 [PubMed... Trends in Microbiology journals http://www.medworm.com/rss/comments.php?id=2902152 Sun, 11 Oct 2009 23:00:00 +0100 2902152 http://www.medworm.com/index.php?rid=2895436&cid=s_36143_77_f&fid=36143&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19822428%26dopt%3DAbstract Authors: Bourne DG, Garren M, Work TM, Rosenberg E, Smith GW, Harvell CD Tropical coral reefs harbour a reservoir of enormous biodiversity that is increasingly threatened by direct human activities and indirect global climate shifts. Emerging coral diseases are one serious threat implicated in extensive reef deterioration through disruption of the integrity of the coral holobiont - a complex symbiosis between the coral animal, endobiotic alga and an array of microorganisms. In this article, we review our current understanding of the role of microorganisms in coral health and disease, and highlight the pressing interdisciplinary research priorities required to elucidate the mechanisms of disease. We advocate an approach that applies knowledge gained from experiences in human and veterin... Trends in Microbiology journals http://www.medworm.com/rss/comments.php?id=2895436 Fri, 09 Oct 2009 23:00:00 +0100 2895436 http://www.medworm.com/index.php?rid=2887535&cid=s_36143_77_f&fid=36143&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19819699%26dopt%3DAbstract Authors: Santos RL, Raffatellu M, Bevins CL, Adams LG, Tükel C, Tsolis RM, Bäumler AJ The lower gastrointestinal tract is densely populated with resident microbial communities (microbiota), which do not elicit overt host responses but rather provide benefit to the host, including niche protection from pathogens. However, introduction of bacteria into the underlying tissue evokes acute inflammation. Non-typhoidal Salmonella serotypes (NTS) elicit this stereotypic host response by actively penetrating the intestinal epithelium and surviving in tissue macrophages. Initial responses generated by bacterial host cell interaction are amplified in tissue through the interleukin (IL)-18/interferon-gamma and IL-23/IL-17 axes, resulting in the activation of mucosal barrier functions aga... Trends in Microbiology journals http://www.medworm.com/rss/comments.php?id=2887535 Thu, 08 Oct 2009 23:00:00 +0100 2887535 http://www.medworm.com/index.php?rid=2866017&cid=s_36143_77_f&fid=36143&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19800796%26dopt%3DAbstract Authors: Lackner G, Partida-Martinez LP, Hertweck C Mycotoxins are compounds of fungal origin that can adversely affect human, animal and plant health through food spoilage or infection, even to the point of epidemics such as turkey X disease and ergotism. The biosynthetic pathways of various mycotoxins (such as aflatoxin and fumonisins) are generally well understood. However, two examples have recently been described where a mycotoxin is not synthesized by the fungus itself but by bacteria residing within the fungal cytosol. These discoveries have implications in various fields, such as ecology, medicine and food processing. PMID: 19800796 [PubMed - as supplied by publisher] (Source: Trends in Microbiology) Trends in Microbiology journals http://www.medworm.com/rss/comments.php?id=2866017 Wed, 30 Sep 2009 23:00:00 +0100 2866017 http://www.medworm.com/index.php?rid=2859235&cid=s_36143_77_f&fid=36143&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19796949%26dopt%3DAbstract Authors: Martín CS, Liu CY, Kielian M The alphaviruses and flaviviruses include many important human pathogens, such as the dengue, West Nile, and Chikungunya viruses. These enveloped viruses infect cells by a membrane fusion reaction triggered by the low pH in endosomes. Fusion is mediated by viral membrane proteins through their acid-dependent conversion from a dimer on the virus surface to a homotrimer inserted into the host cell membrane. Here we review recent studies on the regulatory mechanisms that silence these fusion proteins during virus exit and that sense low pH and mediate protein refolding during virus entry. We discuss results using truncated proteins to dissect the fusion reaction, and future research directions including the development of antiviral therapies agai... Trends in Microbiology journals http://www.medworm.com/rss/comments.php?id=2859235 Mon, 28 Sep 2009 23:00:00 +0100 2859235 http://www.medworm.com/index.php?rid=2839432&cid=s_36143_77_f&fid=36143&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19782570%26dopt%3DAbstract Authors: McLaughlin DJ, Hibbett DS, Lutzoni F, Spatafora JW, Vilgalys R The Fungi comprise a diverse kingdom of eukaryotes that are characterized by a typically filamentous but sometimes unicellular vegetative form, and heterotrophic, absorptive nutrition. Their simple morphologies and variable ecological strategies have confounded efforts to elucidate their limits, phylogenetic relationships, and diversity. Here we review progress in developing a phylogenetic classification of Fungi since Darwin's On the Origin of Species. Knowledge of phylogenetic relationships has been driven by the available characters that have ranged from morphological and ultrastructural to biochemical and genomic. With the availability of multiple gene phylogenies a well-corroborated phylogenetic classification... Trends in Microbiology journals http://www.medworm.com/rss/comments.php?id=2839432 Wed, 23 Sep 2009 23:00:00 +0100 2839432 http://www.medworm.com/index.php?rid=2839433&cid=s_36143_77_f&fid=36143&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19781945%26dopt%3DAbstract This article summarizes the most important medical countermeasures that have mostly been developed since the 2001 events, and highlights current problems and possible avenues for future research. PMID: 19781945 [PubMed - as supplied by publisher] (Source: Trends in Microbiology) Trends in Microbiology journals http://www.medworm.com/rss/comments.php?id=2839433 Tue, 22 Sep 2009 23:00:00 +0100 2839433 http://www.medworm.com/index.php?rid=2839431&cid=s_36143_77_f&fid=36143&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19783441%26dopt%3DAbstract Authors: Kwon-Chung KJ, Sugui JA Heterothallism is dependent upon the obligatory cross-mating between self-sterile homokaryotic individuals and represents a common pattern of sexuality in yeasts and molds. Heterothallic reproductive cycles have recently been discovered in three Aspergillus species of medical and economic importance, namely Aspergillus fumigatus,A. parasiticus and A. flavus. Together with Aspergillus udagawae (Neosartorya udagawae), heterothallism has now been discovered in a total of four aspergilli that affect human health or economy. These fungi appear to express relatively low levels of fertility compared to other heterothallic or homothallic aspergilli and require unusually fastidious environmental parameters to complete the sexual cycle. Because the purpose of sex... Trends in Microbiology journals http://www.medworm.com/rss/comments.php?id=2839431 Mon, 21 Sep 2009 23:00:00 +0100 2839431 http://www.medworm.com/index.php?rid=2839430&cid=s_36143_77_f&fid=36143&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19783442%26dopt%3DAbstract Authors: Samson RY, Bell SD Eukaryotic and prokaryotic orthologs of tubulin play key roles in DNA segregation and cell division processes. Remarkably, recent studies have revealed that cell division can occur in the absence of this highly conserved protein. Members of the hyperthermophilic crenarchaea, that lack tubulin-like proteins, undergo division by binary fission. Here we review how this process is dependent on archaeal homologs of the eukaryotic 'endosomal sorting complex required for transport' (ESCRT) system - an apparatus that plays a pivotal role in a wide range of membrane manipulation processes. Thus, two distinct machineries to drive binary fission have evolved in prokaryotes - one dependent on tubulin-like proteins and one dependent on the ESCRT system. PMID: 1978344... Trends in Microbiology journals http://www.medworm.com/rss/comments.php?id=2839430 Mon, 21 Sep 2009 23:00:00 +0100 2839430 http://www.medworm.com/index.php?rid=2824636&cid=s_36143_77_f&fid=36143&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19766492%26dopt%3DAbstract Authors: Masson-Boivin C, Giraud E, Perret X, Batut J Rhizobia are phylogenetically disparate alpha- and beta-proteobacteria that have achieved the environmentally essential function of fixing atmospheric nitrogen (N(2)) in symbiosis with legumes. All rhizobia elicit the formation of root - or occasionally stem - nodules, plant organs dedicated to the fixation and assimilation of nitrogen. Bacterial colonization of these nodules culminates in a remarkable case of sustained intracellular infection in plants. Rhizobial phylogenetic diversity raised the question of whether these soil bacteria shared a common core of symbiotic genes. In this article, we review the cumulative evidence from recent genomic and genetic analyses pointing toward an unexpected variety of mechanisms that lead to s... Trends in Microbiology journals http://www.medworm.com/rss/comments.php?id=2824636 Wed, 16 Sep 2009 23:00:00 +0100 2824636 http://www.medworm.com/index.php?rid=2824640&cid=s_36143_77_f&fid=36143&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19765997%26dopt%3DAbstract Authors: Dennehy JJ Viruses fully emerge by gaining the ability to sustainably infect new host populations. When the hosts are humans, emerging viruses can present major public health issues, as exemplified by the AIDS pandemic. Therefore, heuristic approaches to identify nascent diseases before they become pandemic would be valuable. Unfortunately, the current patient-based and epidemiological approaches are ill-suited in this regard because they are largely responsive and not predictive. Alternative approaches based on virus evolutionary ecology might have greater potential to predict virus emergence. However, given the difficulties encountered when studying metazoan viruses in this context, the development of new model systems is greatly desirable. Here, I highlight studies that sho... Trends in Microbiology journals http://www.medworm.com/rss/comments.php?id=2824640 Tue, 15 Sep 2009 23:00:00 +0100 2824640 http://www.medworm.com/index.php?rid=2824639&cid=s_36143_77_f&fid=36143&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19765998%26dopt%3DAbstract Authors: Zhong G Chlamydial infections in humans cause severe health problems, including blinding trachoma and sexually transmitted diseases. Although the involved pathogenic mechanisms remain unclear, the ability to replicate and maintain long-term residence in the infected cells seems to significantly contribute to chlamydial pathogenicity. These obligate intracellular parasites maintain a delicate balance between exploiting and protecting their host: they occupy intracellular space and acquire nutrients from the infected cells, but at the same time they have to maintain the integrity of the host cells for the completion of their intracellular growth. For this purpose, chlamydiae hijack certain signaling pathways that prevent the host cells from undergoing apoptosis induced by intrac... Trends in Microbiology journals http://www.medworm.com/rss/comments.php?id=2824639 Tue, 15 Sep 2009 23:00:00 +0100 2824639 http://www.medworm.com/index.php?rid=2824638&cid=s_36143_77_f&fid=36143&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19765999%26dopt%3DAbstract Authors: D'Elia MA, Pereira MP, Brown ED Gene essentiality has emerged as an often-asked question in the wake of bacterial genome sequencing and a renaissance in studies of prokaryotic physiology. Genome-scale efforts at describing essential gene sets have necessarily been carried out under standard and tractable growth conditions in a laboratory setting. In addition to reinforcing our understanding of core bacterial physiology, these studies have also uncovered large numbers of essential genes encoding proteins whose functions remain poorly described. Studies of these and other elements of core physiology have naturally followed and several paradoxes, relating to growth conditions and genetic context, have begun to challenge our understanding of the term "essential gene". Most recentl... Trends in Microbiology journals http://www.medworm.com/rss/comments.php?id=2824638 Tue, 15 Sep 2009 23:00:00 +0100 2824638 http://www.medworm.com/index.php?rid=2824637&cid=s_36143_77_f&fid=36143&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19766000%26dopt%3DAbstract Authors: Bernsel A, Daley DO Proteins embedded in membranes are important for helping the cell adapt to changes in the extracellular milieu and often play key roles in the life cycles of pathogenic microbes. Bioinformatic predictions can provide an estimate of membrane proteins, but experimental approaches of detection are required for a deeper understanding of their functions. To determine the effectiveness of experimental detection approaches, here we collate and discuss data from available proteomic analyses on the inner (or cytoplasmic) membrane of Escherichia coli. We compile a list of proteins that have been experimentally detected and by comparing this to a predicted proteome we identify membrane proteins that have eluded us experimentally. Limitations of current proteomic analy... Trends in Microbiology journals http://www.medworm.com/rss/comments.php?id=2824637 Tue, 15 Sep 2009 23:00:00 +0100 2824637 http://www.medworm.com/index.php?rid=2804950&cid=s_36143_77_f&fid=36143&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19758804%26dopt%3DAbstract Authors: Berends E, Scholtmeijer K, Wösten HA, Bosch D, Lugones LG The market for N-glycosylated therapeutic proteins represents multi-billion dollars in sales and is growing more than 10% each year. This requires cost-effective production platforms that display correct and homogeneous N-glycosylation. Based on recent results, we propose to use mushroom-forming basidiomycetes for the production of N-glycosylated therapeutic proteins. PMID: 19758804 [PubMed - as supplied by publisher] (Source: Trends in Microbiology) Trends in Microbiology journals http://www.medworm.com/rss/comments.php?id=2804950 Sun, 13 Sep 2009 23:00:00 +0100 2804950 http://www.medworm.com/index.php?rid=2804949&cid=s_36143_77_f&fid=36143&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19758805%26dopt%3DAbstract Authors: Sivick KE, Mobley HL PMID: 19758805 [PubMed - as supplied by publisher] (Source: Trends in Microbiology) Trends in Microbiology journals http://www.medworm.com/rss/comments.php?id=2804949 Sun, 13 Sep 2009 23:00:00 +0100 2804949 http://www.medworm.com/index.php?rid=2775317&cid=s_36143_77_f&fid=36143&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19733080%26dopt%3DAbstract Authors: Jousselin A, Metzinger L, Felden B The pleiotropic post-transcriptional regulator Hfq is an RNA chaperone that facilitates pairing interactions between small regulatory RNAs (sRNAs) and their mRNA targets in several bacteria. However, this classical pattern, derived from the Escherichia coli model, is not applicable to the whole bacterial kingdom. In this article we discuss the facultative requirement for Hfq for sRNA-mRNA duplex formation among bacteria and the specific features of the Hfq protein and RNA duplexes that might account for the dispensability or requirement of the chaperone. Apparent links between the need for Hfq, the GC content of bacterial genomes and the free energy of experimentally validated sRNA-mRNA pairing interactions are presented. PMID: 19733080 [... Trends in Microbiology journals http://www.medworm.com/rss/comments.php?id=2775317 Tue, 01 Sep 2009 23:00:00 +0100 2775317 http://www.medworm.com/index.php?rid=2767034&cid=s_36143_77_f&fid=36143&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19726193%26dopt%3DAbstract Authors: Nicholson WL, Schuerger AC, Race MS Since the dawn of the space age, humans have wrestled with concerns about planetary cross-contamination. Spacecraft launched from Earth can transport hitchhiker microbes to new worlds on both robotic and crewed vehicles. As plans proceed for future life detection and human exploration missions, planetary protection considerations are again uppermost on the agendas of mission planners, and microbiologists have an important role to play. PMID: 19726193 [PubMed - as supplied by publisher] (Source: Trends in Microbiology) Trends in Microbiology journals http://www.medworm.com/rss/comments.php?id=2767034 Sun, 30 Aug 2009 23:00:00 +0100 2767034 http://www.medworm.com/index.php?rid=2767033&cid=s_36143_77_f&fid=36143&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19726194%26dopt%3DAbstract Authors: Logares R, Bråte J, Bertilsson S, Clasen JL, Shalchian-Tabrizi K, Rengefors K Until recently, the evolutionary relationships between marine and freshwater microbes were unclear, but the use of molecular phylogenies is beginning to shed light on this subject. An increasing amount of studies are showing that marine and freshwater microbes (including viruses) are usually not closely related, often grouping into distinct marine and freshwater phylogenetic clusters, similar to what has been reported before for macroorganisms. These studies indicate that marine-freshwater transitions have been infrequent events during the diversification of microbes and that most of these transitions occurred a long time ago in evolutionary terms. Here we discuss the significance of recent stud... Trends in Microbiology journals http://www.medworm.com/rss/comments.php?id=2767033 Sun, 30 Aug 2009 23:00:00 +0100 2767033 http://www.medworm.com/index.php?rid=2767032&cid=s_36143_77_f&fid=36143&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19726195%26dopt%3DAbstract Authors: Hendrickx AP, Willems RJ, Bonten MJ, van Schaik W Enterococci have become an important cause of nosocomial infections since the late 1980s. Several surface proteins have been implicated in contributing to infections caused by Enterococcus faecalis and Enterococcus faecium. Understanding the in vivo function of enterococcal surface proteins, particularly their role in directing interactions with the host during infection, is essential to explain the success of enterococci as nosocomial pathogens. Here we review current knowledge of enterococcal LPxTG surface proteins, including aggregation substance, enterococcal surface protein, three collagen-binding microbial surface components that recognize adhesive matrix molecules (Ace, Acm, Scm) and pili (Ebp, PilA and PilB), their inte... Trends in Microbiology journals http://www.medworm.com/rss/comments.php?id=2767032 Sun, 30 Aug 2009 23:00:00 +0100 2767032 http://www.medworm.com/index.php?rid=2767031&cid=s_36143_77_f&fid=36143&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19726196%26dopt%3DAbstract Authors: Liu GY, Nizet V A hallmark feature of several pathogenic microbes is the distinctive color of their colonies when propagated in the clinical laboratory. Such pigmentation comes in a variety of hues, and has often proven useful in presumptive clinical diagnosis. Recent advances in microbial pigment biochemistry and the genetic basis of pigment production have sometimes revealed a more sinister aspect to these curious materials that change the color of reflected light by selective light absorbance. In many cases, the microbial pigment contributes to disease pathogenesis by interfering with host immune clearance mechanisms or by exhibiting pro-inflammatory or cytotoxic properties. We review several examples of pigments that promote microbial virulence, including the golden staphy... Trends in Microbiology journals http://www.medworm.com/rss/comments.php?id=2767031 Sun, 30 Aug 2009 23:00:00 +0100 2767031 http://www.medworm.com/index.php?rid=2752579&cid=s_36143_77_f&fid=36143&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19716705%26dopt%3DAbstract Authors: Spear AM, Loman NJ, Atkins HS, Pallen MJ The Toll/interleukin-1 receptor (TIR) domain plays a crucial role in the mammalian innate immune response. Recently, proteins containing TIR domains have been described in bacteria and it has been suggested that these bacterial proteins are involved in subversion of the vertebrate immune system. Here we describe the distribution of TIR-domain proteins among bacteria, fungi, archaea and viruses and evaluate the subversion hypothesis in the light of our findings. We suggest that most TIR domains in bacteria have nothing to do with subverting eukaryotic cells; instead, TIR domains function simply as general purpose protein-protein interaction domains put to diverse uses. PMID: 19716705 [PubMed - as supplied by publisher] (Source: Trend... Trends in Microbiology journals http://www.medworm.com/rss/comments.php?id=2752579 Wed, 26 Aug 2009 23:00:00 +0100 2752579 http://www.medworm.com/index.php?rid=2703219&cid=s_36143_77_f&fid=36143&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19679480%26dopt%3DAbstract Authors: O'Malley MA Although it is commonly assumed that Darwin had nothing to say about microbes, he did in fact say quite a lot. He included microbes in his Beagle studies of the geographical distribution of organisms and used microscopic organisms as explicit exemplars of how adaptation did not imply increasing complexity. Darwin often discussed microrganismal classification, origins and experimentation in his correspondence. But despite his interests in microbial phenomena, Darwin's impact on microbiological thinking of the late nineteenth century was negligible. This limited response may be connected to today's assumptions about Darwin's neglect of microbes. PMID: 19679480 [PubMed - as supplied by publisher] (Source: Trends in Microbiology) Trends in Microbiology journals http://www.medworm.com/rss/comments.php?id=2703219 Mon, 10 Aug 2009 23:00:00 +0100 2703219 http://www.medworm.com/index.php?rid=2703220&cid=s_36143_77_f&fid=36143&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19674902%26dopt%3DAbstract Authors: Desvaux M, Hébraud M, Talon R, Henderson IR PMID: 19674902 [PubMed - as supplied by publisher] (Source: Trends in Microbiology) Trends in Microbiology journals http://www.medworm.com/rss/comments.php?id=2703220 Sun, 09 Aug 2009 23:00:00 +0100 2703220 http://www.medworm.com/index.php?rid=2682540&cid=s_36143_77_f&fid=36143&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19660950%26dopt%3DAbstract Authors: Bitter W, Houben EN, Luirink J, Appelmelk BJ Bacteria with an outer membrane are faced with a double hydrophobic barrier for protein secretion. To achieve this, several different secretion machineries have evolved. In a recent Opinion article in this journal, Mickaël Desvaux and colleagues [Desvaux, M., et al. (2009) Secretion and subcellular localizations of bacterial proteins: a semantic awareness issue. Trends in microbiology] discuss the nomenclature of these secretion systems. Although we agree that consensus in nomenclature is important, here we discuss an important point that was overlooked. PMID: 19660950 [PubMed - as supplied by publisher] (Source: Trends in Microbiology) Trends in Microbiology journals http://www.medworm.com/rss/comments.php?id=2682540 Mon, 03 Aug 2009 23:00:00 +0100 2682540 http://www.medworm.com/index.php?rid=2682539&cid=s_36143_77_f&fid=36143&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19660951%26dopt%3DAbstract Authors: Rambow-Larsen AA, Petersen EM, Gourley CR, Splitter GA Brucella is an important zoonotic pathogen for which no human vaccine exists. In an infected host, Brucella resides in macrophages but must coordinate expression of multiple virulence factors for successful cell entry and trafficking to acquire this replicative niche. Brucella responds to environmental signals to regulate virulence strategies that circumvent or blunt the host immune response. The Brucella quorum sensing system is a nexus of control for several Brucella virulence factors including flagellar genes and the type IV secretion system. Other sensory transduction systems, such as BvrRS and the newly described LOV-HK, sense environmental factors to control virulence. Here, we examine the contributions of various re... Trends in Microbiology journals http://www.medworm.com/rss/comments.php?id=2682539 Mon, 03 Aug 2009 23:00:00 +0100 2682539 http://www.medworm.com/index.php?rid=2682538&cid=s_36143_77_f&fid=36143&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19660952%26dopt%3DAbstract Authors: Uroz S, Calvaruso C, Turpault MP, Frey-Klett P Soil microbes play an essential role in the environment by contributing to the release of key nutrients from primary minerals that are required not only for their own nutrition but also for that of plants. Although the role of fungi in mineral weathering is beginning to be elucidated, the relative impact of bacteria in this process and the molecular mechanisms involved remain poorly understood. Here, we discuss the ecological relevance of bacterial weathering, mainly in the soil and especially in acidic forest ecosystems, which strongly depend on mineral weathering for their sustainability. We also present highlights from recent studies showing molecular mechanisms and genetic determinants involved in the dissolution of complex mi... Trends in Microbiology journals http://www.medworm.com/rss/comments.php?id=2682538 Mon, 03 Aug 2009 23:00:00 +0100 2682538 http://www.medworm.com/index.php?rid=2682537&cid=s_36143_77_f&fid=36143&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19660953%26dopt%3DAbstract Authors: St Geme JW, Yeo HJ Nontypable Haemophilus influenzae is a common cause of human disease and initiates infection by colonizing the upper respiratory tract. Adherence to respiratory epithelium is an important step in the process of colonization and is influenced by adhesive proteins called adhesins. In approximately 80% of nontypable H. influenzae isolates, the major adhesins are related proteins called HMW1 and HMW2. Here, we summarize recent advances in our understanding of HMW1 and HMW2 as prototype members of the bacterial two-partner secretion pathway and examples of the expanding number of bacterial glycoproteins, highlighting experimental approaches that might be useful in studies of other secreted proteins and glycoproteins. PMID: 19660953 [PubMed - as supplied by pu... Trends in Microbiology journals http://www.medworm.com/rss/comments.php?id=2682537 Mon, 03 Aug 2009 23:00:00 +0100 2682537 http://www.medworm.com/index.php?rid=2682536&cid=s_36143_77_f&fid=36143&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19660954%26dopt%3DAbstract Authors: Tree JJ, Wolfson EB, Wang D, Roe AJ, Gally DL Type III secretion (T3S) systems enable the injection of bacterial proteins through membrane barriers into host cells, either from outside the host cell or from within a vacuole. This system is required for colonization of their ruminant reservoir hosts by enterohaemorrhagic Escherichia coli (EHEC) and might also be important for the etiology of disease in the incidental human host. T3S systems of E. coli inject a cocktail of proteins into epithelial cells that enables bacterial attachment and promotes longer-term colonization in the animal. Here, we review recent progress in our understanding of the regulation of T3S in EHEC, focusing on the induction and assembly of the T3S system, the co-ordination of effector protein expression... Trends in Microbiology journals http://www.medworm.com/rss/comments.php?id=2682536 Mon, 03 Aug 2009 23:00:00 +0100 2682536 http://www.medworm.com/index.php?rid=2682535&cid=s_36143_77_f&fid=36143&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19660955%26dopt%3DAbstract Authors: Brownlie JC, Johnson KN Microbes influence the ecology and evolution of their hosts in a variety of ways, including the formation of life-long beneficial or detrimental parasitic infections. Understanding the molecular and biochemical events that underpin symbiosis - beneficial or parasitic - has been a long-term goal of molecular symbiosis research. In addition to beneficial symbionts provisioning scarce resources to their hosts, a growing body of evidence shows that bacterial symbionts can protect their hosts from parasitic symbionts and predators. Here, we review recent theoretical predictions and experimental observations of symbiont-mediated protection in insects. We discuss the implications that protection has for the ecology and evolution of host, symbiont and pathogen ... Trends in Microbiology journals http://www.medworm.com/rss/comments.php?id=2682535 Mon, 03 Aug 2009 23:00:00 +0100 2682535 http://www.medworm.com/index.php?rid=2580693&cid=s_36143_77_f&fid=36143&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19577927%26dopt%3DAbstract Authors: Torto-Alalibo T, Meng S, Dean RA Filamentous microbes that form highly developed symbiotic associations (ranging from pathogenesis to mutualism) with their hosts include fungi, oomycetes and actinomycete bacteria. These organisms share many common features in growth, development and infection and have evolved similar strategies for neutralizing host defense responses to establish symbioses. Recent advances in sequencing technologies have led to a remarkable increase in the number of sequenced genomes of filamentous organisms. Analysis of the available genomes has provided useful information about genes that might be important for host infection and colonization. However, because many functional similarities among these organisms have arisen by convergent evolution, sequence-ba... Trends in Microbiology journals http://www.medworm.com/rss/comments.php?id=2580693 Thu, 02 Jul 2009 23:00:00 +0100 2580693 http://www.medworm.com/index.php?rid=2580692&cid=s_36143_77_f&fid=36143&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19577928%26dopt%3DAbstract Authors: Arnaud MB, Costanzo MC, Shah P, Skrzypek MS, Sherlock G The Gene Ontology (GO) is a structured controlled vocabulary developed to describe the roles and locations of gene products in a consistent manner and in a way that can be shared across organisms. The unicellular fungus Candida albicans is similar in many ways to the model organism Saccharomyces cerevisiae but, as both a commensal and a pathogen of humans, differs greatly in its lifestyle. With an expanding at-risk population of immunosuppressed patients, increased use of invasive medical procedures, the increasing prevalence of drug resistance and the emergence of additional Candida species as serious pathogens, it has never been more crucial to improve our understanding of Candida biology to guide the development of bet... Trends in Microbiology journals http://www.medworm.com/rss/comments.php?id=2580692 Thu, 02 Jul 2009 23:00:00 +0100 2580692 http://www.medworm.com/index.php?rid=2580691&cid=s_36143_77_f&fid=36143&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19577929%26dopt%3DAbstract Authors: Tyler BM PMID: 19577929 [PubMed - as supplied by publisher] (Source: Trends in Microbiology) Trends in Microbiology journals http://www.medworm.com/rss/comments.php?id=2580691 Thu, 02 Jul 2009 23:00:00 +0100 2580691 http://www.medworm.com/index.php?rid=2580697&cid=s_36143_77_f&fid=36143&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19577471%26dopt%3DAbstract Authors: Korves T, Colosimo ME Knowledge about pathogenesis is increasing dramatically, and most of this information is stored in the scientific literature or in sequence databases. This information can be made more accessible by the use of ontologies or controlled vocabularies. Recently, several ontologies, controlled vocabularies and databases have been developed or adapted for virulence factors and their roles in pathogenesis. Here, we discuss these systems, how they are being used in research and the challenges that remain for developing and applying ontologies for virulence factors. PMID: 19577471 [PubMed - as supplied by publisher] (Source: Trends in Microbiology) Trends in Microbiology journals http://www.medworm.com/rss/comments.php?id=2580697 Wed, 01 Jul 2009 23:00:00 +0100 2580697 http://www.medworm.com/index.php?rid=2580696&cid=s_36143_77_f&fid=36143&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19577472%26dopt%3DAbstract Authors: Christie KR, Hong EL, Cherry JM The quest to characterize each of the genes of the yeast Saccharomyces cerevisiae has propelled the development and application of novel high-throughput (HTP) experimental techniques. To handle the enormous amount of information generated by these techniques, new bioinformatics tools and resources are needed. Gene Ontology (GO) annotations curated by the Saccharomyces Genome Database (SGD) have facilitated the development of algorithms that analyze HTP data and help predict functions for poorly characterized genes in S. cerevisiae and other organisms. Here, we describe how published results are incorporated into GO annotations at SGD and why researchers can benefit from using these resources wisely to analyze their HTP data and predict gene func... Trends in Microbiology journals http://www.medworm.com/rss/comments.php?id=2580696 Wed, 01 Jul 2009 23:00:00 +0100 2580696 http://www.medworm.com/index.php?rid=2580695&cid=s_36143_77_f&fid=36143&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19577473%26dopt%3DAbstract Authors: Giglio MG, Collmer CW, Lomax J, Ireland A The ever-increasing number of microbial sequencing projects necessitates a standardized system for the capture of genomic data to ensure that the flood of information produced can be effectively utilized. The Gene Ontology (GO) provides the standard for gene product annotations in the areas of molecular function, biological process and cellular component. A recent effort by the Plant-Associated Microbe Gene Ontology (PAMGO) Consortium has produced more than 800 new GO terms specific for annotating interactions between microbes and their hosts and other symbiotic interactions. In addition, there have been changes and additions to the GO annotation format and evidence storage system to reflect the needs of the microbial annotation commun... Trends in Microbiology journals http://www.medworm.com/rss/comments.php?id=2580695 Wed, 01 Jul 2009 23:00:00 +0100 2580695 http://www.medworm.com/index.php?rid=2580694&cid=s_36143_77_f&fid=36143&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19577474%26dopt%3DAbstract Authors: McCarthy FM, Mahony TJ, Parcells MS, Burgess SC Understanding the effects of viral infection has typically focused on specific virus-host interactions such as tissue tropism, immune responses and histopathology. However, modeling viral pathogenesis requires information about the functions of gene products from both virus and host, and how these products interact. Recent developments in the functional annotation of genomes using Gene Ontology (GO) and in modeling functional interactions among gene products, together with an increased interest in systems biology, provide an excellent opportunity to generate global interaction models for viral infection. Here, we review how the GO is being used to model viral pathogenesis, with a focus on animal viruses. PMID: 19577474 [PubMe... Trends in Microbiology journals http://www.medworm.com/rss/comments.php?id=2580694 Wed, 01 Jul 2009 23:00:00 +0100 2580694 http://www.medworm.com/index.php?rid=2580700&cid=s_36143_77_f&fid=36143&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19576777%26dopt%3DAbstract Authors: Lindeberg M, Collmer A Disease development is determined by the interplay of host defense processes and pathogen factors that subvert defenses and remodel the host for parasitic benefit. The goal of the Plant-Associated Microbe Gene Ontology (PAMGO) interest group is the development of Gene Ontology (GO) terms that capture the range of biological processes occurring between hosts and symbionts (from mutualists to pathogens). Here, the application of the new GO terms to type III effector proteins (T3Es) from the plant pathogen Pseudomonas syringae serves as an example to systematically document the available extensive data and to reveal shared aspects of interactions with various host plants. Extending the comparison to T3Es deployed by animal pathogens further highlights how G... Trends in Microbiology journals http://www.medworm.com/rss/comments.php?id=2580700 Tue, 30 Jun 2009 23:00:00 +0100 2580700 http://www.medworm.com/index.php?rid=2580699&cid=s_36143_77_f&fid=36143&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19576778%26dopt%3DAbstract Authors: Hu JC, Karp PD, Keseler IM, Krummenacker M, Siegele DA How we classify the genes, products and complexes that are present or absent in genomes, transcriptomes, proteomes and other datasets helps us place biological objects into subsystems with common functions, see how molecular functions are used to implement biological processes and compare the biology of different species and strains. Gene Ontology (GO) is one of the most successful systems for classifying biological function. Although GO is widely used for eukaryotic genomics, it has not yet been widely used for bacterial systems. The potential applications of GO are currently limited by the need to improve the annotation of bacterial genomes with GO and to improve how prokaryotic biology is represented in the ontology. He... Trends in Microbiology journals http://www.medworm.com/rss/comments.php?id=2580699 Tue, 30 Jun 2009 23:00:00 +0100 2580699 http://www.medworm.com/index.php?rid=2580698&cid=s_36143_77_f&fid=36143&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19576779%26dopt%3DAbstract Authors: Chibucos MC, Tseng TT, Setubal JC Myriad symbiotic microbes, ranging from mutualistic through to pathogenic, deliver 'effector' molecules into the cytoplasm or cellular milieu of their hosts to facilitate colonization. Among ecologically and evolutionarily diverse taxa, analogous processes and structures exist to facilitate effector delivery. These include syringe-like injection (bacteria and nematodes), common host-targeting signals (oomycetes and protozoans) and specialized intercellular structures (fungi and oomycetes). Here, we briefly introduce readers to the Gene Ontology (GO), a controlled vocabulary to facilitate comparative genomics of diverse taxa. We also summarize and compare selected mechanisms of effector delivery from various organisms and show how careful annot... Trends in Microbiology journals http://www.medworm.com/rss/comments.php?id=2580698 Tue, 30 Jun 2009 23:00:00 +0100 2580698 http://www.medworm.com/index.php?rid=2474128&cid=s_36143_77_f&fid=36143&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19464181%26dopt%3DAbstract Authors: Vos M Microbiologists have long recognized that the uptake and incorporation of homologous DNA from outside the cell is a common feature of bacteria, with important implications for their evolution. However, the exact reasons why bacteria engage in homologous recombination remain elusive. This Opinion article aims to reinvigorate the debate by examining the costs and benefits that homologous recombination could engender in natural populations of bacteria. It specifically focuses on the hypothesis that homologous recombination is selectively maintained because the genetic variation it generates improves the response of bacterial populations to natural selection, analogous to sex in eukaryotes. PMID: 19464181 [PubMed - in process] (Source: Trends in Microbiology) Trends in Microbiology journals http://www.medworm.com/rss/comments.php?id=2474128 Mon, 01 Jun 2009 04:00:00 +0100 2474128 http://www.medworm.com/index.php?rid=2474126&cid=s_36143_77_f&fid=36143&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19464182%26dopt%3DAbstract Authors: Roberts AP, Mullany P The Tn916 family is a group of mobile genetic elements that are widespread among many commensal and pathogenic bacteria. These elements are found primarily, but not exclusively, in the Firmicutes. They are integrated into the bacterial genome and are capable of conjugative transfer to a new host and, often, intracellular transposition to a different genomic site - hence their name: 'conjugative transposons', or 'integrative conjugative elements'. An increasing variety of Tn916 relatives are being reported from different bacteria, harbouring genes coding for resistance to various antibiotics and the potential to encode other functions, such as lantibiotic immunity. This family of mobile genetic elements has an extraordinary ability to acquire accessory gen... Trends in Microbiology journals http://www.medworm.com/rss/comments.php?id=2474126 Mon, 01 Jun 2009 04:00:00 +0100 2474126 http://www.medworm.com/index.php?rid=2474124&cid=s_36143_77_f&fid=36143&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19464183%26dopt%3DAbstract Authors: Rahman O, Dover LG, Sutcliffe IC Lipoteichoic acids (LTAs) are membrane-anchored molecules in the cell envelopes of Gram-positive bacteria. Until recently, they were considered to be restricted to the Firmicutes, which include important pathogens such as Staphylococcus aureus and Streptococcus pneumoniae. Polyanionic LTAs have fundamentally important roles in divalent cation retention within the Gram-positive cell envelope and thereby influence bacterial cell division. Thus, LTA biosynthesis provides an attractive target for the development of novel antimicrobial interventions. Recent studies, notably two investigations of S. aureus and another of Bacillus subtilis, have greatly improved our understanding of the genetic basis of LTA biosynthesis. In addition, reports have reve... Trends in Microbiology journals http://www.medworm.com/rss/comments.php?id=2474124 Mon, 01 Jun 2009 04:00:00 +0100 2474124 http://www.medworm.com/index.php?rid=2474122&cid=s_36143_77_f&fid=36143&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19464894%26dopt%3DAbstract Authors: Sharples GJ Almost all cellular organisms employ RecA orthologues to guide the strand invasion reactions necessary for DNA recombination and repair. One of the few exceptions to this orthodoxy is a group of gamma-proteobacteria flourishing in obligate intracellular symbiosis with insects and deep-sea clams. The apparent inability of these bacteria to commence the recombinational exchange process seems to confer genetic stability by preventing any further rearrangements or lateral transfer events. Although debate has centred on the absence of selected recombination functions and their impact on a fixed genomic architecture, no explanation has been offered for how bacteria survive the loss of such an integral DNA repair system. This question is addressed here by speculating on h... Trends in Microbiology journals http://www.medworm.com/rss/comments.php?id=2474122 Mon, 01 Jun 2009 04:00:00 +0100 2474122 http://www.medworm.com/index.php?rid=2474121&cid=s_36143_77_f&fid=36143&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19464895%26dopt%3DAbstract Authors: Nicholson WL Recent developments in microbiology, geophysics and planetary sciences raise the possibility that the planets in our solar system might not be biologically isolated. Hence, the possibility of lithopanspermia (the interplanetary transport of microbial passengers inside rocks) is presently being re-evaluated, with implications for the origin and evolution of life on Earth and within our solar system. Here, I summarize our current understanding of the physics of impacts, space transport of meteorites, and the potentiality of microorganisms to undergo and survive interplanetary transfer. PMID: 19464895 [PubMed - in process] (Source: Trends in Microbiology) Trends in Microbiology journals http://www.medworm.com/rss/comments.php?id=2474121 Mon, 01 Jun 2009 04:00:00 +0100 2474121 http://www.medworm.com/index.php?rid=2474140&cid=s_36143_77_f&fid=36143&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19375323%26dopt%3DAbstract Authors: Schertzer JW, Boulette ML, Whiteley M Quorum sensing in bacteria serves as an example of the adaptation of single-celled organisms to engage in cooperative group behaviors. This phenomenon is much more widespread than originally thought, with many different species 'speaking' through various secreted small molecules. Despite some variation in signaling molecules, the principles of quorum sensing are conserved across a wide range of organisms. Small molecules, secreted into the environment, are detected by neighbors who respond by altering gene expression and, as a consequence, behavior. However, it is not known whether these systems evolved specifically for this purpose, or even if their role is exclusive to information trafficking. Rather, clues exist that many quorum sensing... Trends in Microbiology journals http://www.medworm.com/rss/comments.php?id=2474140 Fri, 01 May 2009 04:00:00 +0100 2474140 http://www.medworm.com/index.php?rid=2474138&cid=s_36143_77_f&fid=36143&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19375324%26dopt%3DAbstract Authors: Sudhamsu J, Crane BR Nitric oxide synthases (NOSs) are heme-based monooxygenases that oxidize L-arginine to nitric oxide (NO), a signaling molecule and cytotoxic agent in higher organisms. Although NOS-like activity has been reported in many bacteria, only a few bacterial homologs of mammalian NOSs (mNOSs) have been characterized to date. In contrast to mNOSs, which possess both a catalytic and a reductase domain, the bacterial enzymes lack reductase domains and require the supply of suitable reductants to produce NO. A notable exception is a NOS from a gram-negative bacterium that contains a new type of reductase module. Remarkably, bacterial NOSs seem to have functions that differ from those of mNOSs, including nitration of different metabolites and protection against oxidat... Trends in Microbiology journals http://www.medworm.com/rss/comments.php?id=2474138 Fri, 01 May 2009 04:00:00 +0100 2474138 http://www.medworm.com/index.php?rid=2474136&cid=s_36143_77_f&fid=36143&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19375325%26dopt%3DAbstract Authors: Johne R, Müller H, Rector A, van Ranst M, Stevens H Techniques for the single-step amplification of whole genomes have been developed into powerful tools for phylogenetic analyses, epidemiological studies and studies on genome organization. Recently, the bacteriophage phi29 DNA polymerase has been used for the efficient amplification of circular DNA viral genomes without the need of specific primers by a rolling-circle amplification (RCA) mechanism. Various protocols have been applied for detection of novel viruses, for differentiation between circular and linear forms of viral genomes and for generation of infectious genomic clones directly from specimens. Here, we summarize the broad application of the RCA technique to DNA viruses infecting humans, animals and plants. ... Trends in Microbiology journals http://www.medworm.com/rss/comments.php?id=2474136 Fri, 01 May 2009 04:00:00 +0100 2474136 http://www.medworm.com/index.php?rid=2474134&cid=s_36143_77_f&fid=36143&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19375326%26dopt%3DAbstract Authors: Shapiro BJ, David LA, Friedman J, Alm EJ As we observe the 200th anniversary of Charles Darwin's birth, microbiologists interested in the application of Darwin's ideas to the microscopic world have a lot to celebrate: an emerging picture of the (mostly microbial) Tree of Life at ever-increasing resolution, an understanding of horizontal gene transfer as a driving force in the evolution of microbes, and thousands of complete genome sequences to help formulate and refine our theories. At the same time, quantitative models of the microevolutionary processes shaping microbial populations remain just out of reach, a point that is perhaps most dramatically illustrated by the lack of consensus on how (or even whether) to define bacterial species. Here, we summarize progress and prosp... Trends in Microbiology journals http://www.medworm.com/rss/comments.php?id=2474134 Fri, 01 May 2009 04:00:00 +0100 2474134 http://www.medworm.com/index.php?rid=2474132&cid=s_36143_77_f&fid=36143&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19375916%26dopt%3DAbstract Authors: Young DB, Gideon HP, Wilkinson RJ Tuberculosis is recognized as the world's leading bacterial cause of death. Yet 95% of infection is believed to exist in an asymptomatic 'latent' form that is defined not by the identification of bacteria, but by the host immune response in the form of reactivity to tuberculosis proteins in the tuberculin skin test. It seems likely that clinically defined latent tuberculosis actually represents a spectrum that runs from elimination of live bacilli to subclinical disease: hence, it might be unhelpful to use a single term to describe all these conditions. To support this view, here we focus on recent increased understanding of the heterogeneity in both bacillary physiology and host immune response that potentially illuminates new therapeutic and... Trends in Microbiology journals http://www.medworm.com/rss/comments.php?id=2474132 Fri, 01 May 2009 04:00:00 +0100 2474132 http://www.medworm.com/index.php?rid=2474130&cid=s_36143_77_f&fid=36143&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19375917%26dopt%3DAbstract Authors: Aanen DK, Slippers B, Wingfield MJ Bark beetles are among the most destructive tree pests on the planet. Their symbiosis with fungi has consequently been studied extensively for more than a century. A recent study has identified actinomycete bacteria that are associated with the southern pine beetle and produce specific antibiotics against an antagonist of the beetles' mutualistic fungus. In addition to highlighting the ecological complexity of bark-beetle-microbial symbioses, this work reveals a potential source of novel antibiotics. PMID: 19375917 [PubMed - in process] (Source: Trends in Microbiology) Trends in Microbiology journals http://www.medworm.com/rss/comments.php?id=2474130 Fri, 01 May 2009 04:00:00 +0100 2474130 http://www.medworm.com/index.php?rid=2297645&cid=s_36143_77_f&fid=36143&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19307122%26dopt%3DAbstract Authors: Zalucki YM, Beacham IR, Jennings MP The signal peptide of proteins exported via the general secretory pathway encodes structural features that enable the targeting and export of the protein to the periplasm. Recent studies have shown biased codon usage at the second amino acid position and a high usage of non-optimal codons within the signal peptide. Altering these biases in codon usage can have deleterious effects on protein folding and export. We propose that these codon-usage biases act in concert to optimize the export process through modulating ribosome spacing on the transcript. This highlights a new aspect of protein export and implies that codon usage in the signal peptide encodes signals that are important for protein targeting and export to the periplasm. PMID: 1... Trends in Microbiology journals http://www.medworm.com/rss/comments.php?id=2297645 Sat, 21 Mar 2009 04:00:00 +0100 2297645 http://www.medworm.com/index.php?rid=2284214&cid=s_36143_77_f&fid=36143&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19299131%26dopt%3DAbstract Authors: Carpenter S, Wilson A, Mellor PS In June 2006, bluetongue virus, an arboviral pathogen of ruminants, appeared in northern Europe for the first time, successfully overwintered and subsequently caused substantial losses to the farming sector in 2007 and 2008. This emergence served as a test of how the probability of arboviral incursion into new regions is assessed and has highlighted the reliance of decision making on paradigms that are not always underpinned by basic biological data. In this review, we highlight those areas of the epidemiology of bluetongue that are poorly understood, reflect upon why certain vital areas of research have received little attention and, finally, examine strategies that could aid future risk assessment and intervention. PMID: 19299131 [PubMed ... Trends in Microbiology journals http://www.medworm.com/rss/comments.php?id=2284214 Tue, 17 Mar 2009 04:00:00 +0100 2284214 http://www.medworm.com/index.php?rid=2284213&cid=s_36143_77_f&fid=36143&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19299132%26dopt%3DAbstract Authors: de Jonge R, Thomma BP Lysin motifs (LysMs) have been recognized in prokaryotes and plants as carbohydrate-binding protein modules. Recently, a novel virulence factor with LysMs was characterized from the plant pathogenic fungus Cladosporium fulvum. Here, we present a survey of public sequence data of 70 fungal species to demonstrate that putatively secreted LysM-containing proteins are widespread in the fungal kingdom, as they are found in mammalian and plant pathogenic species, in addition to saprophytes. We propose that these putative LysM effectors might have a role in sequestration of chitin oligosaccharides - breakdown products of fungal cell walls that are released during invasion and act as triggers of host immunity - to dampen host defence. PMID: 19299132 [PubMed -... Trends in Microbiology journals http://www.medworm.com/rss/comments.php?id=2284213 Tue, 17 Mar 2009 04:00:00 +0100 2284213 http://www.medworm.com/index.php?rid=2284212&cid=s_36143_77_f&fid=36143&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19299133%26dopt%3DAbstract Authors: Casadevall A, Nosanchuk JD, Williamson P, Rodrigues ML Recent findings indicate that fungi use vesicular transport to deliver substances across their cell walls. Fungal vesicles are similar to mammalian exosomes and could originate from cytoplasmic multivesicular bodies. Vesicular transport enables the export of large molecules across the cell wall, and vesicles contain lipids, proteins and polysaccharides, many of which are associated with virulence. Concentration of fungal products in vesicles could increase their efficiency in food acquisition and/or delivering potentially noxious substances to other cells, such as amoebae or phagocytes. The discovery of vesicular transport in fungi opens many new avenues for investigation in basic cell biology and pathogenesis. PMID: 1... Trends in Microbiology journals http://www.medworm.com/rss/comments.php?id=2284212 Tue, 17 Mar 2009 04:00:00 +0100 2284212 http://www.medworm.com/index.php?rid=2284211&cid=s_36143_77_f&fid=36143&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19299134%26dopt%3DAbstract Authors: Desvaux M, Hébraud M, Talon R, Henderson IR Extracellular proteins are a subject of intense interest because of their essential roles in bacterial lifestyles. However, several terms related to secretion are used confusingly in the literature, and this is a topical issue in genomics and proteomics. Defining a secreted protein as actively translocated via a secretion system, here, we put into perspective that homologous translocation systems can result in radically different subcellular localizations of a secreted protein. We propose using standardized nomenclature for secretion systems from type I to type VIII for Gram-negative bacteria only, whereas the terms 'Sec' (secretion), 'Tat' (twin-arginine translocation), 'FEA' (flagella export apparatus), 'FPE' (fimbrilin-protei... Trends in Microbiology journals http://www.medworm.com/rss/comments.php?id=2284211 Tue, 17 Mar 2009 04:00:00 +0100 2284211 http://www.medworm.com/index.php?rid=2284210&cid=s_36143_77_f&fid=36143&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19299135%26dopt%3DAbstract Authors: van Rij RP, Berezikov E RNA interference (RNAi) - post-transcriptional gene silencing guided by small interfering RNA (siRNA) - is an important antiviral defense mechanism in insects and plants. Several recent studies in Drosophila identified endogenous siRNAs corresponding to transposons, to structured cellular transcripts and to overlapping convergent transcripts. In addition, one of these studies detected a large pool of Argonaute-2 associated siRNAs that mapped to the genome of flock house virus, a (+) RNA virus. Our bioinformatic analyses indicate that these viral siRNAs mapped in roughly equal proportions to both (+) and (-) viral RNA strands. These reports attribute an important function to RNAi in the defense against parasitic nucleic acids (viruses and transposable el... Trends in Microbiology journals http://www.medworm.com/rss/comments.php?id=2284210 Tue, 17 Mar 2009 04:00:00 +0100 2284210 http://www.medworm.com/index.php?rid=2223295&cid=s_36143_77_f&fid=36143&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19243949%26dopt%3DAbstract Authors: Muralimohan A, Eun YJ, Bhattacharyya B, Weibel DB Materials science offers microbiologists a wide variety of organic and inorganic materials with chemical and physical properties that can be precisely controlled. These materials present new capabilities for isolating, manipulating and studying bacteria and other microorganisms and are poised to transform microbiology. This review summarizes three classes of materials that span a range of length scales (nano, micro and meso) and describes a variety of fundamental questions in microbiology that can be studied by leveraging their properties. PMID: 19243949 [PubMed - as supplied by publisher] (Source: Trends in Microbiology) Trends in Microbiology journals http://www.medworm.com/rss/comments.php?id=2223295 Mon, 23 Feb 2009 05:00:00 +0100 2223295 http://www.medworm.com/index.php?rid=2211567&cid=s_36143_77_f&fid=36143&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19230673%26dopt%3DAbstract Authors: Vautrin E, Vavre F Multiple infections (i.e. the simultaneous infection of a host by multiple microorganisms) have been shown to be a major evolutionary force of eukaryote-prokaryote interactions but have been almost entirely studied in cases of conflicting interactions taking place between horizontally transmitted parasites. Although multiple infections with vertically transmitted symbionts are widespread in nature and especially in invertebrates, the ecological and evolutionary importance of such coexistences remains underexplored and underestimated. By locking the different partners together, vertical transmission creates privileged situations for symbiont-symbiont interactions, especially cooperation and dependence between symbionts, and for the evolution of social behavio... Trends in Microbiology journals http://www.medworm.com/rss/comments.php?id=2211567 Thu, 19 Feb 2009 05:00:00 +0100 2211567 http://www.medworm.com/index.php?rid=2211565&cid=s_36143_77_f&fid=36143&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19231189%26dopt%3DAbstract Authors: Yildiz FH, Visick KL Vibrios are natural inhabitants of aquatic environments and form symbiotic or pathogenic relationships with eukaryotic hosts. Recent studies reveal that the ability of vibrios to form biofilms (i.e. matrix-enclosed, surface-associated communities) depends upon specific structural genes (flagella, pili and exopolysaccharide biosynthesis) and regulatory processes (two-component regulators, quorum sensing and c-di-GMP signaling). Here, we compare and contrast mechanisms and regulation of biofilm formation by Vibrio species, with a focus on Vibrio cholerae, Vibrio parahaemolyticus, Vibrio vulnificus and Vibrio fischeri. Although many aspects are the same, others differ dramatically. Crucial questions that remain to be answered regarding the molecular underpinn... Trends in Microbiology journals http://www.medworm.com/rss/comments.php?id=2211565 Thu, 19 Feb 2009 05:00:00 +0100 2211565 http://www.medworm.com/index.php?rid=2211564&cid=s_36143_77_f&fid=36143&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19231190%26dopt%3DAbstract Authors: Hassett DJ, Sutton MD, Schurr MJ, Herr AB, Caldwell CC, Matu JO The airways of patients afflicted with cystic fibrosis (CF) are colonized by many pathogens, the most predominant of which is the Gram-negative bacterium Pseudomonas aeruginosa. In the thick CF airway mucus, P. aeruginosa forms antibiotic- and phagocyte-resistant structures known as biofilms, which enable the survival and growth of the organism. P. aeruginosa can undergo dramatic genetic, physiological and morphological changes in this milieu. Chronic infection leads to a considerably reduced oxygen tension, and it is believed that some bacteria grow anaerobically, especially during late-stage disease. In this article, factors that enable long-term survival of P. aeruginosa and two novel drug targets (the rhl quor... Trends in Microbiology journals http://www.medworm.com/rss/comments.php?id=2211564 Thu, 19 Feb 2009 05:00:00 +0100 2211564 http://www.medworm.com/index.php?rid=2211566&cid=s_36143_77_f&fid=36143&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19230674%26dopt%3DAbstract Authors: Aresté C, Blackbourn DJ The most recently identified human herpesvirus is Kaposi's sarcoma-associated herpesvirus (KSHV). It causes Kaposi's sarcoma, a tumour occurring most commonly in untreated AIDS patients and the leading cancer of men in certain parts of Africa. KSHV might also contribute to the pathogenesis of primary effusion lymphoma and multicentric Castleman's disease. The genome of KSHV contains 86 genes, almost a quarter of which encode proteins with either demonstrated or potential immunoregulatory activity. They include homologues of cellular proteins and unique KSHV proteins that can deregulate many aspects of the immune response, including T- and B-cell functions, complement activation, the innate antiviral interferon response and natural killer cell activ... Trends in Microbiology journals http://www.medworm.com/rss/comments.php?id=2211566 Wed, 18 Feb 2009 05:00:00 +0100 2211566 http://www.medworm.com/index.php?rid=2191213&cid=s_36143_77_f&fid=36143&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19217298%26dopt%3DAbstract Authors: Coombes BK The emergence of multi-drug resistance and bacteria with increased virulence is a familiar refrain to the contemporary microbiologist. Although intense research over the past decade has ascribed much molecular detail to these processes, more esoteric questions remain: for example, why are some bacteria evolving increased virulence towards humans, what are the genes underpinning this virulence potential and what are the selective pressures that favor these traits? A holistic approach that considers the organismal biology of bacteria with their diverse hosts seems appropriate to begin to tackle such issues. As it happens, the type III secretion system is turning out to be a central player in the adaptation of both parasites and mutualists to diverse hosts. With this i... Trends in Microbiology journals http://www.medworm.com/rss/comments.php?id=2191213 Wed, 11 Feb 2009 05:00:00 +0100 2191213 http://www.medworm.com/index.php?rid=2183322&cid=s_36143_77_f&fid=36143&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19208480%26dopt%3DAbstract Authors: Garzoni C, Kelley WL Many reports have documented that Staphylococcus aureus can invade host cells and persist intracellularly for various periods of time in cell culture models. However, it is not clear whether intracellular persistence of S. aureus also occurs in the course of infections in whole organisms. This is a subject of intense debate and is difficult to assess experimentally. Intracellular persistence would provide S. aureus with an ideal strategy to escape from professional phagocytes and extracellular antibiotics and would promote recrudescent infection. Here, we present a brief overview of the mounting evidence that S. aureus has the potential to internalize and survive within host cells. PMID: 19208480 [PubMed - as supplied by publisher] (Source: Trends in M... Trends in Microbiology journals http://www.medworm.com/rss/comments.php?id=2183322 Sat, 07 Feb 2009 05:00:00 +0100 2183322 http://www.medworm.com/index.php?rid=2131675&cid=s_36143_77_f&fid=36143&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19162480%26dopt%3DAbstract Authors: Sendi P, Proctor RA Increasing evidence indicates that Staphylococcus aureus might be a facultative intracellular pathogen. In particular, certain subpopulations, called small colony variants (SCVs), seem to be well adapted to the intracellular milieu. When compared to 'normal' staphylococcal strains, SCVs show increased uptake by host cells, resistance to intracellular defenses and reduced stimulation of host defenses. We propose that the ability to form two subpopulations with different phenotypes might allow S. aureus the option for both extra- cellular and intra-cellular survival in the host. PMID: 19162480 [PubMed - as supplied by publisher] (Source: Trends in Microbiology) Trends in Microbiology journals http://www.medworm.com/rss/comments.php?id=2131675 Tue, 20 Jan 2009 05:00:00 +0100 2131675 http://www.medworm.com/index.php?rid=2131674&cid=s_36143_77_f&fid=36143&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19162481%26dopt%3DAbstract Authors: Boyd EF, Almagro-Moreno S, Parent MA Acquisition of genomic islands plays a central part in bacterial evolution as a mechanism of diversification and adaptation. Genomic islands are non-self-mobilizing integrative and excisive elements that encode diverse functional characteristics but all contain a recombination module comprised of an integrase, associated attachment sites and, in some cases, a recombination directionality factor. Here, we discuss how a group of related genomic islands are evolutionarily ancient elements unrelated to plasmids, phages, integrons and integrative conjugative elements. In addition, we explore the diversity of genomic islands and their insertion sites among Gram-negative bacteria and discuss why they integrate at a limited number of tRNA genes. ... Trends in Microbiology journals http://www.medworm.com/rss/comments.php?id=2131674 Tue, 20 Jan 2009 05:00:00 +0100 2131674 http://www.medworm.com/index.php?rid=2131673&cid=s_36143_77_f&fid=36143&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19162482%26dopt%3DAbstract Authors: Donlan RM Biofilms might result in healthcare-associated infections and substantially impact healthcare delivery. Bacteriophage (phage) has been used to treat infectious diseases in humans and there is interest in phage to control biofilms. Phages propagate in their bacterial host and many phages produce depolymerases that hydrolyze biofilm extracellular polymers. Drawbacks of phage to consider include narrow host range, bacterial resistance to phage and phage-encoded virulence genes that can incorporate into the host bacterial genome. The immune system might inactivate phage, and impure phage preparations could contain endotoxin. Phage mixtures or engineered phages could provide effective strategies to overcome these obstacles. Lytic bacteriophages could become a new class of... Trends in Microbiology journals http://www.medworm.com/rss/comments.php?id=2131673 Tue, 20 Jan 2009 05:00:00 +0100 2131673 http://www.medworm.com/index.php?rid=2131672&cid=s_36143_77_f&fid=36143&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19162483%26dopt%3DAbstract Authors: Monds RD, O'Toole GA For the past ten years, the developmental model of microbial biofilm formation has served as the major conceptual framework for biofilm research; however, the paradigmatic value of this model has begun to be challenged by the research community. Here, we critically evaluate recent data to determine whether biofilm formation satisfies the criteria requisite of a developmental system. We contend that the developmental model of biofilm formation must be approached as a model in need of further validation, rather than utilized as a platform on which to base empirical research and scientific inference. With this in mind, we explore the experimental approaches required to further our understanding of the biofilm phenotype, highlighting evolutionary and ecologica... Trends in Microbiology journals http://www.medworm.com/rss/comments.php?id=2131672 Tue, 20 Jan 2009 05:00:00 +0100 2131672 http://www.medworm.com/index.php?rid=2047914&cid=s_36143_77_f&fid=36143&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19081723%26dopt%3DAbstract Authors: Adékambi T, Drancourt M, Raoult D The rpoB gene, encoding the beta-subunit of RNA polymerase, has emerged as a core gene candidate for phylogenetic analyses and identification of bacteria, especially when studying closely related isolates. Together with the 16S rRNA gene, rpoB has helped to delineate new bacterial species and refine bacterial community analysis, as well as enabling the monitoring of rifampicin resistance-conferring mutations. Sequencing of rpoB enables efficient estimation of bacterial G+C% content, DNA-DNA hybridization value and average nucleotide identity (percentage of the total genomic sequence shared between two strains) when taxonomic relationships have been firmly established. New identification tools targeting a rpoB gene fragment located between... Trends in Microbiology journals http://www.medworm.com/rss/comments.php?id=2047914 Tue, 09 Dec 2008 05:00:00 +0100 2047914 http://www.medworm.com/index.php?rid=2047913&cid=s_36143_77_f&fid=36143&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19081724%26dopt%3DAbstract Authors: Snyder LA, Loman NJ, Fütterer K, Pallen MJ Flagella are the chief organelles of motility in bacteria. In recent years, several new findings have illuminated the evolution of bacterial flagella, including cut-down versions of the organelle in Buchnera, a dispensable ATPase and structural evidence for homology between FliG (a component of the flagellar motor) and MgtE (a magnesium transporter). However, a fresh examination of the phylogenetic distribution of flagellar genes warns against a simplistic model of early flagellar evolution. PMID: 19081724 [PubMed - as supplied by publisher] (Source: Trends in Microbiology) Trends in Microbiology journals http://www.medworm.com/rss/comments.php?id=2047913 Tue, 09 Dec 2008 05:00:00 +0100 2047913 http://www.medworm.com/index.php?rid=2028094&cid=s_36143_77_f&fid=36143&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19059780%26dopt%3DAbstract Authors: Hutchings MI, Palmer T, Harrington DJ, Sutcliffe IC Gram-positive bacterial lipoproteins are a functionally diverse and important class of peripheral membrane proteins. Recent advances in molecular biology and the availability of whole genome sequence data have overturned many long-held assumptions about the export and processing of these proteins, most notably the recent discovery that not all lipoproteins are exported as unfolded substrates through the general secretion pathway. Here, we review recent discoveries concerning the export and processing of these proteins, their role in virulence in Gram-positive bacteria and their potential as vaccine candidates or targets for new antimicrobials. PMID: 19059780 [PubMed - as supplied by publisher] (Source: Trends in Microbiol... Trends in Microbiology journals http://www.medworm.com/rss/comments.php?id=2028094 Fri, 05 Dec 2008 05:00:00 +0100 2028094 http://www.medworm.com/index.php?rid=2028093&cid=s_36143_77_f&fid=36143&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19059781%26dopt%3DAbstract Authors: Kouwen TR, van Dijl JM Thiol-disulfide oxidoreductases (TDORs) catalyze thiol-disulfide exchange reactions that are crucial for protein activity and stability. Specifically, they can function as thiol oxidases, disulfide reductases or disulfide isomerases. The generally established view is that particular TDORs act unidirectionally within a fixed cascade of specific, sequentially arranged reactions. However, recent studies on both Gram-negative and Gram-positive bacteria imply that this view needs to be expanded, at least for thiol-disulfide exchanges in proteins that are exported from the cytoplasm. Here, we present our opinion that various TDORs can function as interchangeable modules in different thiol-disulfide exchange pathways. Such TDOR modules, thus, fulfil important f... Trends in Microbiology journals http://www.medworm.com/rss/comments.php?id=2028093 Fri, 05 Dec 2008 05:00:00 +0100 2028093 http://www.medworm.com/index.php?rid=2028092&cid=s_36143_77_f&fid=36143&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19062291%26dopt%3DAbstract Authors: Sá-Correia I, Dos Santos SC, Teixeira MC, Cabrito TR, Mira NP The emergence of widespread multidrug resistance (MDR) is a serious challenge for therapeutics, food-preservation and crop protection. Frequently, MDR is a result of the action of drug-efflux pumps, which are able to catalyze the extrusion of unrelated chemical compounds. This review summarizes the current knowledge on the Saccharomyces cerevisiae drug:H(+) antiporters of the major facilitator superfamily (MFS), a group of MDR transporters that is still characterized poorly in eukaryotes. Particular focus is given here to the physiological role and expression regulation of these transporters, while we provide a unified view of new data emerging from functional genomics approaches. Although traditionally describ... Trends in Microbiology journals http://www.medworm.com/rss/comments.php?id=2028092 Wed, 03 Dec 2008 05:00:00 +0100 2028092 http://www.medworm.com/index.php?rid=1930521&cid=s_36143_77_f&fid=36143&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18977141%26dopt%3DAbstract Authors: Forsman A, Weiss RA The pathogenesis of HIV begins with a profound depletion of CD4+ T cells in the gut followed by a long period of clinically silent but dynamic virus replication and diversification with high host cell turnover before the onset of AIDS. The AIDS-defining opportunistic infections and tumors mark the end-point of a long balancing act between virus and host that occurs when CD4+ T cell numbers fall below a level that can sustain immunity. Comparative studies of lentivirus infections in other species show that AIDS is not an inevitable outcome of infection because simian immunodeficiency virus in natural hosts seldom causes disease. What distinguishes pathogenic from 'passenger' infection is a systemic activation of immune responses followed by destruction of th... Trends in Microbiology journals http://www.medworm.com/rss/comments.php?id=1930521 Thu, 30 Oct 2008 04:00:00 +0100 1930521 http://www.medworm.com/index.php?rid=1930520&cid=s_36143_77_f&fid=36143&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18977142%26dopt%3DAbstract Authors: Campbell EM, Hope TJ Technology developed in the past 10 years has dramatically increased the ability of researchers to directly visualize and measure various stages of the HIV type 1 (HIV-1) life cycle. In many cases, imaging-based approaches have filled critical gaps in our understanding of how certain aspects of viral replication occur in cells. Specifically, live cell imaging has allowed a better understanding of dynamic, transient events that occur during HIV-1 replication, including the steps involved in viral fusion, trafficking of the viral nucleoprotein complex in the cytoplasm and even the nucleus during infection and the formation of new virions from an infected cell. In this review, we discuss how researchers have exploited fluorescent microscopy methodologies to o... Trends in Microbiology journals http://www.medworm.com/rss/comments.php?id=1930520 Thu, 30 Oct 2008 04:00:00 +0100 1930520 http://www.medworm.com/index.php?rid=1930519&cid=s_36143_77_f&fid=36143&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18977143%26dopt%3DAbstract Authors: Van Immerseel F, Rood JI, Moore RJ, Titball RW For decades, low doses of antibiotics have been used widely in animal production to promote growth. However, there is a trend to reduce this use of antibiotics in feedstuffs, and legislation is now in place in Europe to prohibit their use in this way. As a consequence, economically important diseases, such as necrotic enteritis (NE) of chickens, that are caused by Clostridium perfringens have become more prevalent. Recent research is creating a paradigm shift in our understanding of the pathogenesis of NE and is now providing information that will be necessary to monitor and control the incidence of NE in poultry. PMID: 18977143 [PubMed - as supplied by publisher] (Source: Trends in Microbiology) Trends in Microbiology journals http://www.medworm.com/rss/comments.php?id=1930519 Thu, 30 Oct 2008 04:00:00 +0100 1930519 http://www.medworm.com/index.php?rid=1930523&cid=s_36143_77_f&fid=36143&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18976920%26dopt%3DAbstract Authors: Huthoff H, Towers GJ Pathogenic viral infections have exerted selection pressure on their hosts to evolve cellular antiviral inhibitors referred to as restriction factors. Examples of such molecules are APOBEC3G, APOBEC3F and TRIM5alpha. APOBEC3G and APOBEC3F are cytidine deaminases that are able to strongly inhibit retroviral replication by at least two mechanisms. They are counteracted by the lentiviral Vif protein. TRIM5alpha binds to sensitive, incoming retroviruses via its C-terminal PRY/SPRY domain and rapidly recruits them to the proteasome before significant viral DNA synthesis can occur. Both of these proteins robustly block retroviral replication in a species-specific way. It remains an open but important question as to whether innate restriction factors such as thes... Trends in Microbiology journals http://www.medworm.com/rss/comments.php?id=1930523 Wed, 29 Oct 2008 04:00:00 +0100 1930523 http://www.medworm.com/index.php?rid=1930522&cid=s_36143_77_f&fid=36143&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18976921%26dopt%3DAbstract Authors: Carrington M, Martin MP, van Bergen J Human leukocyte antigen (HLA) class I loci are essential to an effective immune response against a wide variety of pathogenic microorganisms, and they represent the prototypes for genetic polymorphism that are sustained through balancing selection. The functional significance of HLA class I variation is better exemplified by studies involving HIV type 1 (HIV-1) than any other infectious organism. HLA class I molecules are essential to the acquired immune response, but they are also important in innate immunity as ligands for the killer cell immunoglobulin-like receptors (KIR), which modulate natural killer cell activity. Here we concentrate on the interaction between the HLA-B and KIR3DL1/KIR3DS1 genes, describe the effects of these loci o... Trends in Microbiology journals http://www.medworm.com/rss/comments.php?id=1930522 Wed, 29 Oct 2008 04:00:00 +0100 1930522 http://www.medworm.com/index.php?rid=1921303&cid=s_36143_77_f&fid=36143&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18964016%26dopt%3DAbstract Authors: Valentine LE, Watkins DI HIV infection, once established, is never cleared. Rare individuals do, however, control viral replication to low levels. These successful immune responses are primarily linked to certain class I MHC alleles (MHC-I). Because of this association, many AIDS vaccines in development are designed to generate virus-specific CD8+ T cells. The Merck STEP phase 2b efficacy trial of one such vaccine was recently halted, and declared a failure. Thus, basic questions regarding what constitutes an effective T cell response and how such responses could be elicited by vaccination remain open. The best animal model available to explore such issues is simian immunodeficiency virus infection of rhesus macaques, which serves as the primary proving ground for AIDS vaccine... Trends in Microbiology journals http://www.medworm.com/rss/comments.php?id=1921303 Mon, 27 Oct 2008 04:00:00 +0100 1921303 http://www.medworm.com/index.php?rid=1921302&cid=s_36143_77_f&fid=36143&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18964017%26dopt%3DAbstract Authors: Kiazyk SA, Fowke KR Although chronic immune activation correlates with CD4(+) T cell loss in HIV infection, an understanding of the factors mediating T cell depletion remains incomplete. We propose that reduced expression of CD127 (IL-7 receptor alpha chain, IL-7Ralpha), induced by immune activation, contributes to CD4(+) T cell loss in HIV infection. In particular, loss of CD127 on central memory CD4(+) T cells (T(CM)) severely restrains the regenerative capacity of the memory component of the immune system, resulting in a limited ability to control T cell homeostasis. Studies from both pathogenic and controlled HIV infection indicate that the containment of immune activation and preservation of CD127 expression are critical to the stability of CD4(+) T cells in infection. A ... Trends in Microbiology journals http://www.medworm.com/rss/comments.php?id=1921302 Mon, 27 Oct 2008 04:00:00 +0100 1921302 http://www.medworm.com/index.php?rid=1921301&cid=s_36143_77_f&fid=36143&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18964018%26dopt%3DAbstract Authors: Davenport MP, Loh L, Petravic J, Kent SJ HIV-1 mutates extensively in vivo to escape immune control by CD8+ T cells (CTLs). The CTL escape mutant virus might also revert back to wild-type upon transmission to new hosts if significant fitness costs are incurred by the mutation. Immune escape and reversion can be extremely fast if they occur very early after infection, whereas they are much slower when they begin later during infection. Immune escape presents a significant barrier to vaccination, because escape of vaccine-mediated immune responses could neutralise any benefits of vaccination. Here, we consider the dynamics of immune escape and reversion in vivo in natural infection, and suggest how understanding of this can be used to predict optimal vaccine targets and design v... Trends in Microbiology journals http://www.medworm.com/rss/comments.php?id=1921301 Mon, 27 Oct 2008 04:00:00 +0100 1921301 http://www.medworm.com/index.php?rid=1921300&cid=s_36143_77_f&fid=36143&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18964019%26dopt%3DAbstract Authors: Bernstein A PMID: 18964019 [PubMed - as supplied by publisher] (Source: Trends in Microbiology) Trends in Microbiology journals http://www.medworm.com/rss/comments.php?id=1921300 Mon, 27 Oct 2008 04:00:00 +0100 1921300 http://www.medworm.com/index.php?rid=1921299&cid=s_36143_77_f&fid=36143&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18964020%26dopt%3DAbstract Authors: Willey S, Aasa-Chapman MM Several features of HIV have frustrated efforts to develop a vaccine able to induce broadly neutralising antibodies. The enormous genetic diversity of HIV is a major factor, accompanied by the camouflaged nature of the envelope spike, upon which HIV depends for cellular entry and to which antibodies must bind to neutralise. The picture is further complicated by the presence of nonfunctional envelope glycoproteins on the surface of HIV that are immunogenic. Consequently, HIV attracts antibodies that do not directly neutralise the virus but still activate complement and engage Fc receptors, which can both enhance and inhibit infection. The various effects that anti-envelope antibodies have on HIV infection will be reviewed here. Further research is need... Trends in Microbiology journals http://www.medworm.com/rss/comments.php?id=1921299 Mon, 27 Oct 2008 04:00:00 +0100 1921299 http://www.medworm.com/index.php?rid=1921298&cid=s_36143_77_f&fid=36143&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18964021%26dopt%3DAbstract Authors: de Silva TI, Cotten M, Rowland-Jones SL HIV type 2 (HIV-2), a closely related retrovirus discovered a few years after HIV type 1, causes AIDS in only a minority of infected individuals. Determining why HIV-2 causes asymptomatic infection in most patients could further our understanding of HIV immunopathogenesis. Studies to date have suggested that both enhanced immune responses and lower viral replication could play a role. We summarize the important findings to date and highlight areas that warrant further exploration. PMID: 18964021 [PubMed - as supplied by publisher] (Source: Trends in Microbiology) Trends in Microbiology journals http://www.medworm.com/rss/comments.php?id=1921298 Mon, 27 Oct 2008 04:00:00 +0100 1921298 http://www.medworm.com/index.php?rid=1921297&cid=s_36143_77_f&fid=36143&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18964022%26dopt%3DAbstract This article argues that the 'economics' of antiretroviral drug delivery is at heart a political-economy of access to treatment. It depends on commitment on the part of national governments to negotiate with pharmaceutical companies over patented antiretroviral drug prices, on their policy towards compulsory licensing, and on the approach they adopt to delivering HAART. Civil society has an important role to play in encouraging governments to become, and remain, committed to taking action to ensure sustainable and widespread access to HAART. PMID: 18964022 [PubMed - as supplied by publisher] (Source: Trends in Microbiology) Trends in Microbiology journals http://www.medworm.com/rss/comments.php?id=1921297 Mon, 27 Oct 2008 04:00:00 +0100 1921297 http://www.medworm.com/index.php?rid=1856565&cid=s_36143_77_f&fid=36143&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18835715%26dopt%3DAbstract Authors: Plieva FM, Galaev IY, Noppe W, Mattiasson B There is a great demand for improved technologies with regard to rapid processing of nano- and microparticles. The handling of viruses in addition to microbial and mammalian cells requires the availability of appropriate adsorbents. Recent developments in macroporous gels produced at subzero temperatures (known as cryogels) have demonstrated an efficiency for processing cell and virus suspensions, cell separation and cell culture applications. Their unique combination of properties such as macroporosity, tissue-like elasticity and biocompatibility, physical and chemical stability and ease of preparation, renders these materials interesting candidates for a broad range of potential applications within microbiological research. This re... Trends in Microbiology journals http://www.medworm.com/rss/comments.php?id=1856565 Sat, 04 Oct 2008 04:00:00 +0100 1856565 http://www.medworm.com/index.php?rid=1856567&cid=s_36143_77_f&fid=36143&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18835713%26dopt%3DAbstract Authors: Ryndak M, Wang S, Smith I The Mycobacterium tuberculosis PhoPR two-component system is essential for virulence in animal models of tuberculosis. Recent articles have shown that among the reasons for the attenuation of the M. tuberculosis H37Ra strain is a mutation in the phoP gene that prevents the secretion of proteins that are important for virulence. There is a need for new anti-tubercular therapies because of the emergence of multi-drug-resistant M. tuberculosis strains and also the variable efficacy of the currently used bacille Calmette-Guérin vaccine. Because of its major role in M. tuberculosis pathogenicity, PhoP is a potential target candidate. This review summarizes our understanding of PhoPR's role in virulence and discusses areas in which our knowledge is lim... Trends in Microbiology journals http://www.medworm.com/rss/comments.php?id=1856567 Fri, 03 Oct 2008 04:00:00 +0100 1856567 http://www.medworm.com/index.php?rid=1856566&cid=s_36143_77_f&fid=36143&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18835714%26dopt%3DAbstract Authors: Rechsteiner MP, Bernasconi M, Berger C, Nadal D The oncogenic Epstein-Barr virus (EBV) infects the majority of the human population without doing harm and establishes a latent infection in the memory B-cell compartment. To accomplish this, EBV hijacks B-cell differentiation pathways and uses its own viral genes to interfere with B-cell signalling to achieve life-long persistence. EBV latent membrane protein 2A (LMP2A) provides a surrogate B-cell receptor signal essential for cell survival and is believed to have a crucial role in the maintenance of latency by blocking B-cell activation which would otherwise lead to lytic EBV infection. These two functions demand tight control of LMP2A activity and expression levels. Based on recent insights in the function of LMP2B, an isoform... Trends in Microbiology journals http://www.medworm.com/rss/comments.php?id=1856566 Fri, 03 Oct 2008 04:00:00 +0100 1856566 http://www.medworm.com/index.php?rid=1848207&cid=s_36143_77_f&fid=36143&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18829323%26dopt%3DAbstract Authors: Parkhill J PMID: 18829323 [PubMed - as supplied by publisher] (Source: Trends in Microbiology) Trends in Microbiology journals http://www.medworm.com/rss/comments.php?id=1848207 Mon, 29 Sep 2008 04:00:00 +0100 1848207 http://www.medworm.com/index.php?rid=1837610&cid=s_36143_77_f&fid=36143&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18819801%26dopt%3DAbstract Authors: Whitworth DE The availability of bacterial genome sequences has ushered in an era of post-genomic research - accelerating and often enabling molecular genetic analyses. For bacteriologists focussing on an individual bacterium, comparing genomes has also led to a greater understanding of their favoured organism through contextualization. But how does the value of such contextualization vary with the number of available genomes? It seems that for most genome metrics, comparison against approximately 100 genomes is sufficient, with comparison against further genomes not considerably affecting the contextual knowledge gained. It appears that quality, rather than quantity, might be the most important factor when comparing genomes. PMID: 18819801 [PubMed - as supplied by publish... Trends in Microbiology journals http://www.medworm.com/rss/comments.php?id=1837610 Wed, 24 Sep 2008 04:00:00 +0100 1837610 http://www.medworm.com/index.php?rid=1837609&cid=s_36143_77_f&fid=36143&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18819802%26dopt%3DAbstract Authors: Guttman JA, Finlay BB Pathogenic microorganisms routinely exploit host cellular functions for their benefit. These alterations often enhance the survival and/or dissemination of the pathogen. However, these effects on the host can be quite debilitating. Consequently, an in-depth understanding of the molecular mechanisms employed by pathogens to manipulate their hosts is crucial. One of the common host phenotypes elicited by enteric pathogens is the generation of diarrhea. Here, we overview the current advances in understanding strategies used by bacterial pathogens to cause diarrheal diseases and discuss how the coordination of various subcellular events can influence disease progression. PMID: 18819802 [PubMed - as supplied by publisher] (Source: Trends in Microbiology) Trends in Microbiology journals http://www.medworm.com/rss/comments.php?id=1837609 Wed, 24 Sep 2008 04:00:00 +0100 1837609 http://www.medworm.com/index.php?rid=1837608&cid=s_36143_77_f&fid=36143&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18819803%26dopt%3DAbstract Authors: Soanes DM, Talbot NJ Plant pathogenic microbes secrete proteins known as effectors, which enter the cytoplasm of plant cells and suppress host defences. Known effectors in oomycete pathogens possess an RXLR-EER motif in their amino acid sequence that is necessary for transport of the effector into a host plant cell. A large number of putative effectors have now been identified in oomycete genomes, the sequences of which show evidence of diversifying selection at their C terminus. Here, we describe recent progress in characterizing RXLR-EER effectors and discuss why so many of these rapidly evolving proteins are encoded by the genomes of plant pathogenic oomycetes. PMID: 18819803 [PubMed - as supplied by publisher] (Source: Trends in Microbiology) Trends in Microbiology journals http://www.medworm.com/rss/comments.php?id=1837608 Wed, 24 Sep 2008 04:00:00 +0100 1837608 http://www.medworm.com/index.php?rid=1794837&cid=s_36143_77_f&fid=36143&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18789693%26dopt%3DAbstract Authors: Hardoim PR, van Overbeek LS, Elsas JD Bacterial endophytes live inside plants for at least part of their life cycle. Studies of the interaction of endophytes with their host plants and their function within their hosts are important to address the ecological relevance of endophytes. The modulation of ethylene levels in plants by bacterially produced 1-aminocyclopropane-1-carboxylate deaminase is a key trait that enables interference with the physiology of the host plant. Endophytes with this capacity might profit from association with the plant, because colonization is enhanced. In turn, host plants benefit by stress reduction and increased root growth. This mechanism leads to the concept of 'competent' endophytes, defined as endophytes that are equipped with genes important f... Trends in Microbiology journals http://www.medworm.com/rss/comments.php?id=1794837 Thu, 11 Sep 2008 04:00:00 +0100 1794837 http://www.medworm.com/index.php?rid=1794836&cid=s_36143_77_f&fid=36143&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18789694%26dopt%3DAbstract Authors: Roberts KL, Smith GL Vaccinia virus is the smallpox vaccine. It is the most intensively studied poxvirus, and its study has provided important insights about virus replication in general and the interactions of viruses with the host cell and immune system. Here, the entry, morphogenesis and dissemination of vaccinia virus are considered. These processes are complicated by the existence of two infectious vaccinia virus particles, called intracellular mature virus (IMV) and extracellular enveloped virus (EEV). The IMV particle is surrounded by one membrane, and the EEV particle comprises an IMV particle enclosed within a second lipid membrane containing several viral antigens. Consequently, these virions have different biological properties and play different roles in the virus ... Trends in Microbiology journals http://www.medworm.com/rss/comments.php?id=1794836 Thu, 11 Sep 2008 04:00:00 +0100 1794836 http://www.medworm.com/index.php?rid=1794835&cid=s_36143_77_f&fid=36143&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18789695%26dopt%3DAbstract Authors: Chattopadhyay MK PMID: 18789695 [PubMed - as supplied by publisher] (Source: Trends in Microbiology) Trends in Microbiology journals http://www.medworm.com/rss/comments.php?id=1794835 Wed, 10 Sep 2008 04:00:00 +0100 1794835 http://www.medworm.com/index.php?rid=1788993&cid=s_36143_77_f&fid=36143&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18783952%26dopt%3DAbstract Authors: Tannock GW The bowels of humans contain resident bacterial communities, the members of which are numerous and biodiverse. Changes in the composition of bowel communities is accepted to occur in relation to antibiotic-associated colitis of the elderly, but compositional alterations could also be relevant to allergic diseases in children and inflammatory bowel diseases (i.e. Crohn's disease and ulcerative colitis). It is timely, therefore, to reflect on current knowledge of the bacterial community of the human bowel in relation to disease. Modern analytical methods provide tools by which compositional shifts in bacterial communities can be detected, but inadequate bowel-sampling procedures and poorly designed studies hamper progress. Moreover, demonstration that population shift... Trends in Microbiology journals http://www.medworm.com/rss/comments.php?id=1788993 Mon, 08 Sep 2008 04:00:00 +0100 1788993 http://www.medworm.com/index.php?rid=1775864&cid=s_36143_77_f&fid=36143&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18774297%26dopt%3DAbstract Authors: Källenius G, Pawlowski A, Hamasur B, Svenson SB There is an urgent need for an efficient vaccine against tuberculosis. Here, we explore the potential role of carbohydrate antigens as part of a new tuberculosis vaccine. Emphasis is placed on carbohydrate-protein conjugate vaccines, using the arabinomannan portion of lipoarabinomannan, a major structural surface component of Mycobacterium tuberculosis covalently conjugated to (mycobacterial) protein antigens. Such conjugate vaccines show good protective efficacy in mice and guinea pigs in terms of prolonged survival and reduced pathology. Special attention is paid to the immunology underlying their protective capacity. Conjugate vaccines induce both cellular and humoral responses and, although antibody responses have been t... Trends in Microbiology journals http://www.medworm.com/rss/comments.php?id=1775864 Thu, 04 Sep 2008 04:00:00 +0100 1775864 http://www.medworm.com/index.php?rid=1775863&cid=s_36143_77_f&fid=36143&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18774298%26dopt%3DAbstract Authors: Rao CV, Glekas GD, Ordal GW Adaptation has a crucial role in the gradient-sensing mechanism that underlies bacterial chemotaxis. The Escherichia coli chemotaxis pathway uses a single adaptation system involving reversible receptor methylation. In Bacillus subtilis, the chemotaxis pathway seems to use three adaptation systems. One involves reversible receptor methylation, although quite differently than in E. coli. The other two involve CheC, CheD and CheV, which are chemotaxis proteins not found in E. coli. Remarkably, no one system is absolutely required for adaptation or is independently capable of generating adaptation. In this review, we discuss these three novel adaptation systems in B. subtilis and propose a model for their integration. PMID: 18774298 [PubMed - as su... Trends in Microbiology journals http://www.medworm.com/rss/comments.php?id=1775863 Thu, 04 Sep 2008 04:00:00 +0100 1775863 http://www.medworm.com/index.php?rid=1775862&cid=s_36143_77_f&fid=36143&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18775660%26dopt%3DAbstract Authors: Verstraeten N, Braeken K, Debkumari B, Fauvart M, Fransaer J, Vermant J, Michiels J Swarming is the fastest known bacterial mode of surface translocation and enables the rapid colonization of a nutrient-rich environment and host tissues. This complex multicellular behavior requires the integration of chemical and physical signals, which leads to the physiological and morphological differentiation of the bacteria into swarmer cells. Here, we provide a review of recent advances in the study of the regulatory pathways that lead to swarming behavior of different model bacteria. It has now become clear that many of these pathways also affect the formation of biofilms, surface-attached bacterial colonies. Decision-making between rapidly colonizing a surface and biofilm formation is ... Trends in Microbiology journals http://www.medworm.com/rss/comments.php?id=1775862 Wed, 03 Sep 2008 04:00:00 +0100 1775862 http://www.medworm.com/index.php?rid=1726655&cid=s_36143_77_f&fid=36143&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18715784%26dopt%3DAbstract Authors: De Buck E, Lammertyn E, Anné J The twin-arginine translocation (Tat) pathway is a prokaryotic transport system that enables the transport of folded proteins across the cytoplasmic membrane. The Tat pathway was originally thought to transport only proteins that bind cofactors in the cytoplasm and, thus, fold before transport, like many proteins related to energy metabolism. However, in recent years it has become clear that the Tat pathway has a broader role and is also an important virulence factor in different bacterial pathogens. Because the Tat pathway is well conserved among important bacterial pathogens and absent from mammalian cells, it could be a target for novel antimicrobial compounds. In this review, we highlight the importance of the Tat system for virulence in... Trends in Microbiology journals http://www.medworm.com/rss/comments.php?id=1726655 Mon, 18 Aug 2008 04:00:00 +0100 1726655 http://www.medworm.com/index.php?rid=1717702&cid=s_36143_77_f&fid=36143&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18707886%26dopt%3DAbstract Authors: Guerry P, Szymanski CM The amazing repertoire of glycoconjugates that are found in Campylobacter jejuni includes lipooligosaccharides mimicking human glycolipids, capsular polysaccharides with complex and unusual sugars, and proteins that are post-translationally modified with either O- or N-linked glycans. Thus, the glycome of this important food-borne pathogen is an excellent toolbox for glycobiologists to understand the fundamentals of these pathways and their role in host-microbe interactions, develop new techniques for glycobiology and exploit these pathways for novel diagnostics and therapeutics. The exciting surge in recent research activities will be summarized in this review. PMID: 18707886 [PubMed - as supplied by publisher] (Source: Trends in Microbiology) Trends in Microbiology journals http://www.medworm.com/rss/comments.php?id=1717702 Thu, 14 Aug 2008 04:00:00 +0100 1717702 http://www.medworm.com/index.php?rid=1717704&cid=s_36143_77_f&fid=36143&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18706814%26dopt%3DAbstract Authors: White PC, Böhm M, Marion G, Hutchings MR Bovine tuberculosis (bTB; Mycobacterium bovis) is a bacterial infection of cattle that also affects certain wildlife species. Culling badgers (Meles meles), the principal wildlife host, results in perturbation of the badger population and an increased level of disease in cattle. Therefore, the priority for future management must be to minimize the risk of disease transmission by finding new ways to reduce the contact rate among the host community. At the farm level, targeting those individuals that represent an elevated risk of transmission might prove to be effective. At the landscape level, risk mapping can provide the basis for targeted surveillance of the host community. Here, we review the current evidence for bTB persistence ... Trends in Microbiology journals http://www.medworm.com/rss/comments.php?id=1717704 Wed, 13 Aug 2008 04:00:00 +0100 1717704 http://www.medworm.com/index.php?rid=1717703&cid=s_36143_77_f&fid=36143&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18706815%26dopt%3DAbstract Authors: Backert S, Fronzes R, Waksman G Many type-IV secretion systems (T4SSs) of plant and human pathogens assemble a pilus used to inject virulence molecules (effectors) into host target cells. The T4SS of Agrobacterium tumefaciens consists of VirB1-VirB11 and VirD4 proteins. Whether targeting of T4SSs to the host requires a T4SS-adhesin that specifically engages host receptors for delivery of effectors has, until recently, remained unclear. Recent data of Agrobacterium and Helicobacter indicate that two classes of T4SS components, VirB2 and VirB5, might function as adhesins that mediate host-cell targeting through binding to specific host receptors. Here, we discuss this important issue and recent progress in the field. PMID: 18706815 [PubMed - as supplied by publisher] (Source... Trends in Microbiology journals http://www.medworm.com/rss/comments.php?id=1717703 Wed, 13 Aug 2008 04:00:00 +0100 1717703 http://www.medworm.com/index.php?rid=1709866&cid=s_36143_77_f&fid=36143&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18701293%26dopt%3DAbstract Authors: Ten Bokum AM, Movahedzadeh F, Frita R, Bancroft GJ, Stoker NG Deletion of genes in a pathogen is commonly associated with a reduction in its ability to cause disease. However, some rare cases have been described in the literature whereby deletion of a gene results in an increase in virulence. Recently, there have been several reports of hypervirulence resulting from gene deletion in Mycobacterium tuberculosis. Here, we explore this phenomenon in the context of the interaction between the pathogen and the host response. PMID: 18701293 [PubMed - as supplied by publisher] (Source: Trends in Microbiology) Trends in Microbiology journals http://www.medworm.com/rss/comments.php?id=1709866 Mon, 11 Aug 2008 04:00:00 +0100 1709866 http://www.medworm.com/index.php?rid=1701550&cid=s_36143_77_f&fid=36143&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18691890%26dopt%3DAbstract Authors: Hess M Growing concerns about global climate change and energy dependence have led to an increased effort to reduce carbon emissions. A considerable reduction could be achieved by using biofuels from lignocellulosic biomass instead of fossil fuels. One major bottleneck of biofuel production from lignocellulose is the availability of efficient and inexpensive biocatalysts (i.e. alcohol dehydrogenases, cellulases and esterases) that are active and stable at high temperatures and low pH values. Although heterologous gene expression is used effectively to obtain recombinant proteins derived from mesophiles, the production of thermoacidophilic proteins is often unsuccessful. Some of the reasons for this failure and potential solutions for an increased production of novel extremophi... Trends in Microbiology journals http://www.medworm.com/rss/comments.php?id=1701550 Wed, 06 Aug 2008 04:00:00 +0100 1701550 http://www.medworm.com/index.php?rid=1701549&cid=s_36143_77_f&fid=36143&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18691891%26dopt%3DAbstract Authors: Briggs DC, Day AJ PMID: 18691891 [PubMed - as supplied by publisher] (Source: Trends in Microbiology) Trends in Microbiology journals http://www.medworm.com/rss/comments.php?id=1701549 Wed, 06 Aug 2008 04:00:00 +0100 1701549 http://www.medworm.com/index.php?rid=1638030&cid=s_36143_77_f&fid=36143&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18632274%26dopt%3DAbstract Authors: Zhu S Cystatins, the cysteine protease inhibitors, and the cathelin-like domain (CLD) of the antimicrobial cathelicidins are classified into the same superfamily because of their overall structural similarity. However, their evolutionary relationship has remained obscure owing to low sequence similarity. Structural similarity of two proteins often provides evidence for divergent evolution; however, structural convergence can not be completely ruled out in this case. Conserved gene structure and related function provide new evidence in favor of a common ancestral origin for cystatins and CLDs. On the basis of two observations, the C-terminal location of the cathelicidin antimicrobial domain and evolutionary gain of one 3' intron, I propose a gradual evolution model to explain h... Trends in Microbiology journals http://www.medworm.com/rss/comments.php?id=1638030 Mon, 14 Jul 2008 04:00:00 +0100 1638030 http://www.medworm.com/index.php?rid=1631776&cid=s_36143_77_f&fid=36143&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18619843%26dopt%3DAbstract Authors: Chaturongakul S, Raengpradub S, Wiedmann M, Boor KJ Listeria monocytogenes can respond rapidly to changing environmental conditions, as illustrated by its ability to transition from a saprophyte to an orally transmitted facultative intracellular pathogen. Differential associations between various alternative sigma factors and a core RNA polymerase provide a transcriptional mechanism for regulating bacterial gene expression that is crucial for survival in rapidly changing conditions. Alternative sigma factors are key components of complex L. monocytogenes regulatory networks that include multiple transcriptional regulators of stress-response and virulence genes, regulation of genes encoding other regulators, and regulation of small RNAs. In this article, the contributions of va... Trends in Microbiology journals http://www.medworm.com/rss/comments.php?id=1631776 Wed, 09 Jul 2008 04:00:00 +0100 1631776 http://www.medworm.com/index.php?rid=1631775&cid=s_36143_77_f&fid=36143&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18619844%26dopt%3DAbstract Authors: Wessler S, Backert S Intact intercellular junctions and cell-matrix contacts are important structures in the formation and maintenance of epithelial-barrier functions against microbes. The human gastric pathogen Helicobacter pylori developed a remarkable network of strategies to alter these epithelial cell-cell and cell-matrix adhesions, which are implicated in inflammation, proliferation, cell migration and invasive growth. This review focuses on recent findings on H. pylori-induced host-cell signaling. We propose a stepwise model for how H. pylori interacts with components of focal adhesions and intercellular tight and adherens junctions to disrupt the epithelial layer, providing novel insights into the pathogenesis of H. pylori. PMID: 18619844 [PubMed - as supplied by p... Trends in Microbiology journals http://www.medworm.com/rss/comments.php?id=1631775 Wed, 09 Jul 2008 04:00:00 +0100 1631775 http://www.medworm.com/index.php?rid=1577582&cid=s_36143_77_f&fid=36143&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18595713%26dopt%3DAbstract Authors: West JS, Atkins SD, Emberlin J, Fitt BD Plant, animal and human diseases spread by microscopic airborne particles have had major economic and social impacts during history. Special air-sampling devices have been used to collect such particles since the 19th century but it has often been impossible to identify them accurately. Exciting new opportunities to combine air sampling with quantitative PCR to identify and count these particles are reviewed, using crop pathogen examples. These methods can be used to predict the risk of unexpected outbreaks of airborne diseases by identifying increases in pathogen inoculum or genetic changes in pathogen populations that render control ineffective. The predictions can provide guidance to policymakers, health professionals or the agricultu... Trends in Microbiology journals http://www.medworm.com/rss/comments.php?id=1577582 Mon, 30 Jun 2008 04:00:00 +0100 1577582 http://www.medworm.com/index.php?rid=1577581&cid=s_36143_77_f&fid=36143&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18595714%26dopt%3DAbstract Authors: Yen YT, Kostakioti M, Henderson IR, Stathopoulos C The serine protease autotransporters of the Enterobacteriaceae (SPATEs) represent a group of large-sized, multi-domain exoproteins found only in pathogenic enteric bacteria. These proteins contain a highly conserved channel-forming C-terminal domain, which functions together with YaeT/Omp85 to facilitate secretion of the passenger domain to the cell surface. The C-terminal domain also mediates autoproteolytic cleavage, which releases the passenger from the bacterial cell. The passenger folds into a characteristic parallel beta-helical stalk-like structure with an N-terminal globular domain that performs serine proteolytic activity. Here, we review and discuss recent findings that have led to a better understanding of these uni... Trends in Microbiology journals http://www.medworm.com/rss/comments.php?id=1577581 Mon, 30 Jun 2008 04:00:00 +0100 1577581 http://www.medworm.com/index.php?rid=1561450&cid=s_36143_77_f&fid=36143&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18585915%26dopt%3DAbstract Authors: Diep BA, Otto M The recent emergence of community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) marked a quantum change in the biology and epidemiology of a major human pathogen. Various virulence determinants unique to CA-MRSA have been uncovered recently, which shed light on how these strains spread easily and sustainably among humans and frequently cause severe disease. The role of the Panton Valentine leukocidin (PVL) in CA-MRSA pathogenesis is a matter of much debate. Although epidemiological data have indicated a role for PVL in the CA-MRSA disease process, recent data from relevant animal models indicate that PVL does not impact virulence of prevalent CA-MRSA strains. Identifying specialized pathogenic traits of CA-MRSA remains a challenge that will y... Trends in Microbiology journals http://www.medworm.com/rss/comments.php?id=1561450 Thu, 26 Jun 2008 04:00:00 +0100 1561450 http://www.medworm.com/index.php?rid=1516941&cid=s_36143_77_f&fid=36143&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18547810%26dopt%3DAbstract Authors: Bashan A, Yonath A Ribosome research has undergone astonishing progress in recent years. Crystal structures have shed light on the functional properties of the translation machinery and revealed how the striking architecture of the ribosome is ingeniously designed as the framework for its unique capabilities: precise decoding, substrate-mediated peptide-bond formation and efficient polymerase activity. New findings include the two concerted elements of tRNA translocation: sideways shift and a ribosomal-navigated rotatory motion; the dynamics of the nascent-chain exit tunnel and the shelter formed by the ribosome-bound trigger-factor, which acts as a chaperone to prevent nascent-chain aggregation and misfolding. The availability of these structures has also illuminated the acti... Trends in Microbiology journals http://www.medworm.com/rss/comments.php?id=1516941 Mon, 09 Jun 2008 04:00:00 +0100 1516941 http://www.medworm.com/index.php?rid=1509375&cid=s_36143_77_f&fid=36143&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18539032%26dopt%3DAbstract Authors: Ghosh AS, Chowdhury C, Nelson DE Bacterial cell shape is, in part, mediated by the peptidoglycan (murein) sacculus. Penicillin-binding proteins (PBPs) catalyze the final stages of murein biogenesis and are the targets of beta-lactam antibiotics. Several low molecular mass PBPs including PBP4, PBP5, PBP6 and DacD seem to possess DD-carboxypeptidase (DD-CPase) activity, but these proteins are dispensable for survival in laboratory culture. The physiological functions of DD-CPases in vivo are unresolved and it is unclear why bacteria retain these seemingly non-essential and enzymatically redundant enzymes. However, PBP5 clearly contributes to maintenance of cell shape in some PBP mutant backgrounds. In this review, we focus on recent findings concerning the physiological function... Trends in Microbiology journals http://www.medworm.com/rss/comments.php?id=1509375 Thu, 05 Jun 2008 04:00:00 +0100 1509375 http://www.medworm.com/index.php?rid=1488918&cid=s_36143_77_f&fid=36143&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18515114%26dopt%3DAbstract Authors: Jang J, Becq J, Gicquel B, Deschavanne P, Neyrolles O Most mycobacteria are environmental species, causing disease only occasionally when they encounter a susceptible human or animal host. A few species, such as Mycobacterium tuberculosis and Mycobacterium avium, have acquired the ability to parasitize host macrophages during the course of evolution and have become major pathogens. Recent genetic studies in these two species have suggested that early episodes of horizontal transfer of genomic islands from surrounding environmental species might have contributed to the evolution towards this virulence phenotype, possibly by helping bacilli to persist in protozoa and, subsequently, in mammalian phagocytes. A better understanding of the function of the proteins encoded by these g... Trends in Microbiology journals http://www.medworm.com/rss/comments.php?id=1488918 Sat, 31 May 2008 04:00:00 +0100 1488918 http://www.medworm.com/index.php?rid=1488920&cid=s_36143_77_f&fid=36143&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18513971%26dopt%3DAbstract Authors: Ralph AP, Kelly PM, Anstey NM Worsening drug resistance and the need for prolonged treatment in tuberculosis (TB) require innovative solutions including investigation of inexpensive, safe adjunctive immunotherapies. L-arginine, the precursor of nitric oxide, and vitamin D recently have elucidated mycobactericidal and immunomodulatory actions against TB and are deficient in people with TB. We review the potential of these agents as adjunctive TB immunotherapies and explore how comparative clinical trials might help clarify their relative importance in the human TB immune response. By enhancing mycobacterial killing in macrophages, L-arginine and vitamin D might have the potential to enable shorter duration of treatment, reduced infectivity and improved response in drug-resistan... Trends in Microbiology journals http://www.medworm.com/rss/comments.php?id=1488920 Wed, 28 May 2008 04:00:00 +0100 1488920 http://www.medworm.com/index.php?rid=1488919&cid=s_36143_77_f&fid=36143&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18513972%26dopt%3DAbstract Authors: Ohkuma M The microbial community in the gut of phylogenetically lower termites, comprising both flagellated protists and prokaryotes, has fascinated many scientists because of the symbiotic relationships that are responsible for the efficient degradation of lignocellulose. However, the complex nature of this microbial community and the formidable unculturability of most members have hampered detailed microbial studies. Comprehensive phylogenetic descriptions of the community members in the past decade still provide little information about their functions because the community contains diverse novel microbial species. Recent advances in molecular approaches have shed new light on species-specific spatial distributions, particularly the cellular associations of flagellated prot... Trends in Microbiology journals http://www.medworm.com/rss/comments.php?id=1488919 Wed, 28 May 2008 04:00:00 +0100 1488919 http://www.medworm.com/index.php?rid=1478333&cid=s_36143_77_f&fid=36143&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18508271%26dopt%3DAbstract Authors: Shelburne SA, Davenport MT, Keith DB, Musser JM Historically, the study of bacterial catabolism of complex carbohydrates has contributed to understanding basic bacterial physiology. Recently, however, genome-wide screens of streptococcal pathogenesis have identified genes encoding proteins involved in complex carbohydrate catabolism as participating in pathogen infectivity. Subsequent studies have focused on specific mechanisms by which carbohydrate utilization proteins might contribute to the ability of streptococci to colonize and infect the host. Moreover, transcriptome and biochemical analyses have uncovered novel regulatory pathways by which streptococci link environmental carbohydrate availability to virulence factor production. Herein we review new insights into the rol... Trends in Microbiology journals http://www.medworm.com/rss/comments.php?id=1478333 Tue, 27 May 2008 04:00:00 +0100 1478333 http://www.medworm.com/index.php?rid=1440227&cid=s_36143_77_f&fid=36143&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18468900%26dopt%3DAbstract Authors: Werner F Evolutionarily related multisubunit RNA polymerases (RNAPs) facilitate gene transcription throughout the three domains of life. During the past seven years an increasing number of bacterial and eukaryotic RNAP structures have been solved; however, the archaeal enzyme remained elusive. Two reports from the Murakami and Cramer laboratories have now filled this gap in our knowledge and enable us to hypothesize about the evolution of the structure and function of RNAPs. PMID: 18468900 [PubMed - as supplied by publisher] (Source: Trends in Microbiology) Trends in Microbiology journals http://www.medworm.com/rss/comments.php?id=1440227 Fri, 09 May 2008 04:00:00 +0100 1440227 http://www.medworm.com/index.php?rid=1433973&cid=s_36143_77_f&fid=36143&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18467096%26dopt%3DAbstract Authors: Earl AM, Losick R, Kolter R Bacillus subtilis is a remarkably diverse bacterial species that is capable of growth within many environments. Recent microarray-based comparative genomic analyses have revealed that members of this species also exhibit considerable genomic diversity. The identification of strain-specific genes might explain how B. subtilis has become so broadly adapted. The goal of identifying ecologically adaptive genes could soon be realized with the imminent release of several new B. subtilis genome sequences. As we embark upon this exciting new era of B. subtilis comparative genomics we review what is currently known about the ecology and evolution of this species. PMID: 18467096 [PubMed - as supplied by publisher] (Source: Trends in Microbiology) Trends in Microbiology journals http://www.medworm.com/rss/comments.php?id=1433973 Wed, 07 May 2008 04:00:00 +0100 1433973 http://www.medworm.com/index.php?rid=1433972&cid=s_36143_77_f&fid=36143&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18467097%26dopt%3DAbstract We describe the diversity of their iron-uptake mechanisms and highlight the importance of the process for virulence. PMID: 18467097 [PubMed - as supplied by publisher] (Source: Trends in Microbiology) Trends in Microbiology journals http://www.medworm.com/rss/comments.php?id=1433972 Wed, 07 May 2008 04:00:00 +0100 1433972