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 'Microbiology' source. Mon, 06 Feb 2012 21:32:19 +0100 http://www.medworm.com/index.php?rid=5621056&cid=s_37896_77_f&fid=37896&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22262094%26dopt%3DAbstract Authors: Wetzel J, Burmester A, Kolbe M, Wöstemeyer J Abstract The putative mating type locus of mucoralean fungi consists of a single HMG-domain transcription factor gene, sexM or sexP, flanked by genes for an RNA helicase and a TP transporter. We used degenerated primers derived from the amino acid sequence of the RNA helicase for sequencing a fragment of this gene from Mucor mucedo. By inverse PCR this fragment was extended to obtain partial sequences of the sex loci from both mating types of Mucor mucedo. The sex loci in Mucor mucedo reflect the general picture obtained previously for Phycomyces blakesleeanus, presenting a single HMG-transcription factor gene, sexM in the minus and sexP in the plus mating type. These are located next to a gene for RNA helicase, too. Transcript... Microbiology journals http://www.medworm.com/rss/comments.php?id=5621056 Thu, 19 Jan 2012 05:00:00 +0100 5621056 http://www.medworm.com/index.php?rid=5621055&cid=s_37896_77_f&fid=37896&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22262095%26dopt%3DAbstract Authors: Selin C, Fernando DW, de Kievit TR Abstract The aim of the current study was to determine how quorum sensing (QS) affects the production of secondary metabolites in Pseudomonas chlororaphis strain PA23. A phzR mutant (PA23phzR) and an AHL-deficient strain (PA23-6863) were generated that no longer inhibited the fungal pathogen Sclerotinia sclerotiorum in vitro. Both strains exhibited reduced pyrrolnitrin (PRN), phenazine (PHZ), and protease production. Moreover, phzA-lacZ and prnA-lacZ transcription was significantly reduced in PA23phzR and PA23-6863. As the majority of secondary metabolites are produced at the onset of stationary phase, we investigated whether cross-regulation occurs between QS and RpoS. Analysis of transcriptional fusions revealed that RpoS has a positive... Microbiology journals http://www.medworm.com/rss/comments.php?id=5621055 Thu, 19 Jan 2012 05:00:00 +0100 5621055 http://www.medworm.com/index.php?rid=5621054&cid=s_37896_77_f&fid=37896&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22262096%26dopt%3DAbstract Authors: Liu MF, Cescau S, Mechold U, Wang J, Cohen D, Danchin A, Boulouis HJ, Biville F Abstract In Escherichia coli, only one essential oligoribonuclease (Orn) can degrade oligoribonucleotides of five residues and shorter in length (nanoRNA). In Bacillus subtilis, NrnA and NrnB, which do not have any sequence similarity with Orn, have been identified as functional analogs of Orn. Sequence comparisons did not allow identifying orn, nrnA, or nrnB homologues in the genomes of the Chlamydia/Cyanobacteria and Alphaproteobacteria family members. Screening a genomic library from Bartonella birtlesii, a member of the Alphaproteobacteria, for genes that can complement a conditional orn mutant in E. coli, we identified BA0969 (NrnC) as functional analog of Orn. NrnC is well conserved (more... Microbiology journals http://www.medworm.com/rss/comments.php?id=5621054 Thu, 19 Jan 2012 05:00:00 +0100 5621054 http://www.medworm.com/index.php?rid=5621053&cid=s_37896_77_f&fid=37896&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22262097%26dopt%3DAbstract Authors: Fujiwara K, Taguchi H Abstract The chaperonin GroE (GroEL and the co-chaperonin GroES) is the only chaperone system that is essential for the viability of Escherichia coli. GroE is absolutely required for the folding of at least 57 proteins in E. coli, referred to as class IV substrates, and assists in the folding of many more. Although GroE is mainly involved in protein folding, when it is depleted, the expression levels of about a hundred further proteins can be seen to increase, most prominently methionine synthase (MetE). Here we investigate the mechanism of metE overexpression in GroE-depleted cells. Gene fusion experiments in which the metE transcriptional region was fused to an assayable reporter, showed that addition of a GroE-independent MetK (MetK synthesizes S-a... Microbiology journals http://www.medworm.com/rss/comments.php?id=5621053 Thu, 19 Jan 2012 05:00:00 +0100 5621053 http://www.medworm.com/index.php?rid=5621052&cid=s_37896_77_f&fid=37896&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22262098%26dopt%3DAbstract Authors: Aguirre-Ramírez M, Medina GE, González-Valdez A, Grosso-Becerra MV, Soberón-Chávez G Abstract Pseudomonas aeruginosa produces the biosurfactants rhamnolipids, containing one (mono-rhamnolipid) or two (di-rhamnolipid) L-rhamnose molecules. Rhamnosyltransferase RhlB catalyzes the synthesis of mono-rhamnolipid using as precursors dTDP-L-rhamnose and 3-(3-hydroxyalkanoyloxy)alkanoic acids (HAAs) produced by RhlA, while rhamnosyltransferase RhlC synthesizes di-rhamnolipid using mono-rhamnolipid and dTDP-L-rhamnose as substrates. The Las and Rhl quorum sensing systems coordinately regulate the production of these surfactants, as well as other exoproducts involved in bacterial virulence, at the transcription level in a cell density dependent manner. In this work we study the ... Microbiology journals http://www.medworm.com/rss/comments.php?id=5621052 Thu, 19 Jan 2012 05:00:00 +0100 5621052 http://www.medworm.com/index.php?rid=5621051&cid=s_37896_77_f&fid=37896&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22262099%26dopt%3DAbstract We report here a BSH dependent detoxification mechanism in S. aureus. When S. aureus Newman strain was treated with monobromobimane and monochlorobimane the cellular BSH was converted to the fluorescent S-conjugate, BS-bimane. A bacillithiol conjugate amidase activity acted upon the BS-bimane to produce Cys-bimane, which was then acetylated by an N-acetyltransferase to generate N-acetyl-Cys-bimane, a mercapturic acid. An S. aureus mutant lacking BSH does not produce mercapturic acid when treated with monobromobimane and monochlorobimane, confirming the involvement of bacillithiol. Furthermore, treatment of S. aureus Newman with rifamycin, the parent compound of the first line anti- tuberculosis drug, rifampin, indicated that this thiol reactive antibiotic is also detoxified in a BSH depend... Microbiology journals http://www.medworm.com/rss/comments.php?id=5621051 Thu, 19 Jan 2012 05:00:00 +0100 5621051 http://www.medworm.com/index.php?rid=5621050&cid=s_37896_77_f&fid=37896&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22262100%26dopt%3DAbstract In this study, we identified P. aeruginosa PA3191 as a novel host responsive sensor that played a key role during P. aeruginosa-host interactions and was required for optimum colonisation and dissemination in a mouse model of infection. We demonstrated PA3191 contributed to modulation of the Type III Secretion System (T3SS) in response to host cells and T3SS inducing conditions in vitro. PA3191 (designated GtrS) acted in concert with the response regulator GltR to regulate the OprB transport system and subsequently carbon metabolism. Through this signal transduction pathway, T3SS activation was mediated via the RsmAYZ regulatory cascade and involved the global anaerobic response regulator Anr. PMID: 22262100 [PubMed - as supplied by publisher] (Source: Microbiology) Microbiology journals http://www.medworm.com/rss/comments.php?id=5621050 Thu, 19 Jan 2012 05:00:00 +0100 5621050 http://www.medworm.com/index.php?rid=5621049&cid=s_37896_77_f&fid=37896&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22262101%26dopt%3DAbstract Authors: Wu CC, Lin CT, Cheng WY, Huang CJ, Wang ZC, Peng HL Abstract Type 3 fimbriae play a crucial role in Klebsiella pneumoniae biofilm formation, but the mechanism of the regulation of the type 3 fimbrial operon is largely unknown. In K. pneumoniae CG43, 3 regulatory genes, mrkH, mrkI, and mrkJ, are located downstream to the type 3 fimbrial genes mrkABCDF. The production of major pilin MrkA is abolished by the deletion of mrkH or mrkI but slightly increased by the deletion of mrkJ. Additionally, quantitative RT-PCR and a promoter-reporter assay of mrkHI verified that the transcription of mrkHI was activated by MrkI, suggesting an auto-activation of mrkHI transcription. In addition, sequence analysis of the mrkH promoter region revealed a putative ferric uptake regulator (Fur) b... Microbiology journals http://www.medworm.com/rss/comments.php?id=5621049 Thu, 19 Jan 2012 05:00:00 +0100 5621049 http://www.medworm.com/index.php?rid=5621048&cid=s_37896_77_f&fid=37896&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22262102%26dopt%3DAbstract We examined the role of lactobacillic acid in B. abortus virulence by creating a mutant in ORF BAB1_0476, the putative CFA synthase gene. The mutant did not incorporate [14C]-methyl groups into lipids, lacked CFAs and synthesized the unsaturated precursors, proving that BAB1_0476 actually encodes a CFA synthase. BAB1_0476 promotor-luxAB fusion studies showed that CFA synthase expression was promoted by acid pH and high osmolarity. The mutant was not attenuated in macrophages or mice, strongly suggesting that CFAs are not essential for B. abortus intracellular life. However, when the mutant was tested under high osmolarity on agar and acid pH, two conditions likely to occur on contaminated materials and fomites, they showed reduced ability to growth or survive. Since CFA synthesis entails h... Microbiology journals http://www.medworm.com/rss/comments.php?id=5621048 Thu, 19 Jan 2012 05:00:00 +0100 5621048 http://www.medworm.com/index.php?rid=5599524&cid=s_37896_77_f&fid=37896&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22241045%26dopt%3DAbstract In this study iron accessibility was found to effect fHbp transcription. However, regulation differed among meningococcal clonal complexes (cc). For the majority of isolates increased iron concentrations upregulated transcription. This effect was enhanced by the presence of an 181bp insertion element upstream of fHbp, associated with isolates belonging to cc4 and cc5. Conversely, meningococci belonging to cc32 showed iron-repressed control of fHbp as regulation was dominated by cotranscription with the iron-repressed upstream gene, cbbA. These results highlight the complexity of fHbp regulation and demonstrate that control of transcription can vary among genetic lineages. PMID: 22241045 [PubMed - as supplied by publisher] (Source: Microbiology) Microbiology journals http://www.medworm.com/rss/comments.php?id=5599524 Thu, 12 Jan 2012 05:00:00 +0100 5599524 http://www.medworm.com/index.php?rid=5599523&cid=s_37896_77_f&fid=37896&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22241046%26dopt%3DAbstract We report here that cereulide operated for B. cereus as a tool to scavenge potassium when the environment is growth limiting for this ion. Cereulide producing B. cereus showed higher maximal growth rates (µmax) than cereulide non-producing B. cereus in K+ deficient medium, [K+] ~ 1 mM. The cereulide producing strains grew faster in K+ deficient than in K+ rich medium with or without added cereulide. Cereulide non-producing B. cereus neither increased µmax in K+ deficient medium compared to K+ rich medium, nor benefited from added cereulide. Cereulide producing strains outcompeted GFP-labeled B. thuringiensis in potassium deficient ([K+] ~1 mM) but not in potassium rich ([K+] ~30 mM) medium. Exposure to 2 µM of cereulide in potassium free medium void of energy source caused within second... Microbiology journals http://www.medworm.com/rss/comments.php?id=5599523 Thu, 12 Jan 2012 05:00:00 +0100 5599523 http://www.medworm.com/index.php?rid=5599522&cid=s_37896_77_f&fid=37896&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22241047%26dopt%3DAbstract This study examined 49 field isolates of the genus Avibacterium, with these 49 being allocated to 36 epidemiologically unrelated groups with one isolate from each group being examined in detail. In addition, six type and reference strains were investigated. Phylogenetic analysis of partially sequenced recN, rpoB, infB, pgi and sodA genes confirmed the existence of the species Avibacterium paragallinarum, while a species complex encompassing Avibacterium volantium, Avibacterium avium, Avibacterium gallinarum, Avibacterium endocarditis and Avibacterium sp. A could not be resolved. All isolates shared at least one identical sequence in one gene, indicating low diversity or horizontal gene transfer between isolates. Such horizontal gene transfer between isolates of defined species and unclassi... Microbiology journals http://www.medworm.com/rss/comments.php?id=5599522 Thu, 12 Jan 2012 05:00:00 +0100 5599522 http://www.medworm.com/index.php?rid=5599521&cid=s_37896_77_f&fid=37896&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22241048%26dopt%3DAbstract Authors: Quinn MJ, Resch CT, Sun J, Lind EJ, Dibrov P, Häse C Abstract Vibrio cholerae has adapted to a wide range of salinity, pH and osmotic conditions, enabling it to survive passage through the host and persist in the environment. Among the many proteins responsible for bacterial survival under these diverse conditions, we have identified Vc-NhaP1 as a K(+)(Na(+))/H(+) antiporter essential for V. cholerae growth at low environmental pH. Deletion of the V. cholerae nhaP1 gene caused growth inhibition when external potassium was either limited (100 mM and below) or in excess (400 mM and above). This growth defect was most apparent at mid-logarithmic phase, after 4-6 hours of culturing. Using a pH-sensitive GFP protein, cytosolic pH was shown to be dependent on K+ in acidic exter... Microbiology journals http://www.medworm.com/rss/comments.php?id=5599521 Thu, 12 Jan 2012 05:00:00 +0100 5599521 http://www.medworm.com/index.php?rid=5599520&cid=s_37896_77_f&fid=37896&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22241049%26dopt%3DAbstract Authors: Pinske C, Macdowall JS, Sargent F, Sawers RG Abstract Two of the three [NiFe]-hydrogenases (Hyd) of Escherichia coli have a hydrogen-uptake function in anaerobic metabolism. While Hyd-2 is maximally synthesized when the bacterium grows by fumarate respiration, Hyd-1 synthesis shows a correlation with fermentation of sugar substrates. In an attempt to advance our knowledge on the physiological function of Hyd-1 during fermentative growth, we examined Hyd-1 activity and levels in various derivatives of E. coli K-12 MC4100 with specific defects in sugar utilisation. MC4100 lacks a functional fructose phosphotransferase system (PTS) and therefore grows more slowly under anaerobic conditions in rich medium in the presence of D-fructose compared to D-glucose. Growth in the prese... Microbiology journals http://www.medworm.com/rss/comments.php?id=5599520 Thu, 12 Jan 2012 05:00:00 +0100 5599520 http://www.medworm.com/index.php?rid=5599519&cid=s_37896_77_f&fid=37896&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22241050%26dopt%3DAbstract Authors: Biørnstad TJ, Ohnstad HS, Havarstein LS Abstract Recently it has been shown that Streptococcus thermophilus is competent for natural genetic transformation. This property is widespread among streptococci and might include all members of the genus. Upon entering the competent state streptococci start transcribing a number of competence-specific genes whose products are required for binding, uptake and processing of transforming DNA. In addition to the core competence genes, competent streptococci express a number of accessory genes that are dispensable for transformation in the laboratory, but presumably play an important role under natural conditions. In Streptococcus pneumoniae one of these accessory genes encodes a competence-specific murein hydrolase termed CbpD. Exper... Microbiology journals http://www.medworm.com/rss/comments.php?id=5599519 Thu, 12 Jan 2012 05:00:00 +0100 5599519 http://www.medworm.com/index.php?rid=5578076&cid=s_37896_77_f&fid=37896&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22222496%26dopt%3DAbstract In conclusion expression of the chimeric PspC confers adhesive properties to L. lactis and indicates the potential of L. lactis as a suitable host to study the impact of individual bacterial factors on their capacity to interfere with the host and manipulate eukaryotic epithelial cells. PMID: 22222496 [PubMed - as supplied by publisher] (Source: Microbiology) Microbiology journals http://www.medworm.com/rss/comments.php?id=5578076 Thu, 05 Jan 2012 05:00:00 +0100 5578076 http://www.medworm.com/index.php?rid=5578075&cid=s_37896_77_f&fid=37896&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22222497%26dopt%3DAbstract Authors: Perry RD, Craig SK, Abney J, Bobrov AG, Kirillina O, Mier I, Truszczynska H, Fetherston JD Abstract Yersinia pestis has a flea-mammal-flea transmission cycle and is a zoonotic pathogen that causes the systemic diseases bubonic and septicemic plague in rodents and humans as well as pneumonic plague in humans and non-human primates. Bubonic and pneumonic plague are quite different diseases resulting from different routes of infection. Manganese (Mn) acquisition is critical for the growth and pathogenesis of a number of bacteria. The Yfe/Sit and/or MntH systems are the two prominent Mn transporters in Gram-negative bacteria. Previously we showed that the Y. pestis Yfe system transports Fe and Mn. Here we demonstrate that a mutation in yfe or mntH did not significantly affect ... Microbiology journals http://www.medworm.com/rss/comments.php?id=5578075 Thu, 05 Jan 2012 05:00:00 +0100 5578075 http://www.medworm.com/index.php?rid=5578074&cid=s_37896_77_f&fid=37896&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22222498%26dopt%3DAbstract Authors: Jakovleva J, Teppo A, Velts A, Saumaa S, Moor H, Kivisaar M, Teras R Abstract An important link between the environment and the physiological state of bacteria is the regulation of the transcription of a large number of genes by global transcription factors. One of the global regulators, Fis (factor for inversion stimulation), is well studied in Escherichia coli, but the role of this protein in pseudomonads has only been examined briefly. According to the studies in Enterobacteriaceae, Fis regulates positively the flagellar movement of bacteria. In pseudomonads flagellar movement is an important trait for the colonization of plant roots. Therefore we were interested in the role of the Fis protein in Pseudomonas putida, especially the possible regulation of the colonization... Microbiology journals http://www.medworm.com/rss/comments.php?id=5578074 Thu, 05 Jan 2012 05:00:00 +0100 5578074 http://www.medworm.com/index.php?rid=5578073&cid=s_37896_77_f&fid=37896&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22222499%26dopt%3DAbstract Authors: Jamerson M, da Rocha-Azevedo B, Cabral GA, Marciano-Cabral F Abstract Naegleria fowleri and Naegleria lovaniensis are closely related free-living amebae found in the environment. N. fowleri causes Primary Amebic Meningoencephalitis (PAM), a rapidly fatal disease of the central nervous system, while N. lovaniensis is non-pathogenic. N. fowleri infection occurs when the amebae access the nasal passages, attach to the nasal mucosa and its epithelial lining, and migrate to the brain. This process involves interaction with components of the host extracellular matrix (ECM). Since the ability to invade tissues can be a characteristic that distinguishes pathogenic from non-pathogenic amebae, the objective of this study was to assess adhesion to, and invasion of, the ECM by these t... Microbiology journals http://www.medworm.com/rss/comments.php?id=5578073 Thu, 05 Jan 2012 05:00:00 +0100 5578073 http://www.medworm.com/index.php?rid=5578072&cid=s_37896_77_f&fid=37896&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22222500%26dopt%3DAbstract Authors: Valdes-Santiago L, Cervantes-Chavez JA, Winkler R, León-Ramírez CG, Ruiz-Herrera J Abstract Synthesis of spermidine involves the action of two enzymes: spermidine synthase (Spe), and S-adenosylmethionine decarboxylase (Samdc). Previously we cloned and disrupted the gene encoding Spe as a first approach to unravel the biological function of spermidine in Ustilago maydis. With this background, the present study was designed to provide a better understanding of the role played by Samdc in the regulation of the synthesis of this polyamine. To this aim we proceeded to isolate and delete the gene encoding Samdc from U. maydis, and made a comparative analysis of the phenotype of samdc and spe mutants. Both spe and samdc mutants behaved as spermidine auxotrophs, and were more se... Microbiology journals http://www.medworm.com/rss/comments.php?id=5578072 Thu, 05 Jan 2012 05:00:00 +0100 5578072 http://www.medworm.com/index.php?rid=5578078&cid=s_37896_77_f&fid=37896&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22210803%26dopt%3DAbstract Authors: Harman GE, Herrera-Estrella AH, Horwitz BA, Lorito M PMID: 22210803 [PubMed - in process] (Source: Microbiology) Microbiology journals http://www.medworm.com/rss/comments.php?id=5578078 Sun, 01 Jan 2012 05:00:00 +0100 5578078 http://www.medworm.com/index.php?rid=5578077&cid=s_37896_77_f&fid=37896&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22210804%26dopt%3DAbstract Authors: Huergo LF, Pedrosa FO, Muller-Santos M, Chubatsu LS, Monteiro RA, Merrick M, Souza EM Abstract The fixation of atmospheric nitrogen by the prokaryotic enzyme nitrogenase is an energy- expensive process and consequently it is tightly regulated at a variety of levels. In many diazotrophs this includes post-translational regulation of the enzyme's activity, which has been reported in both bacteria and archaea. The best understood response is the short-term inactivation of nitrogenase in response to a transient rise in ammonium levels in the environment. A number of proteobacteria species effect this regulation through reversible ADP-ribosylation of the enzyme, but other prokaryotes have evolved different mechanisms. Here we review current knowledge of post-translational contr... Microbiology journals http://www.medworm.com/rss/comments.php?id=5578077 Sun, 01 Jan 2012 05:00:00 +0100 5578077 http://www.medworm.com/index.php?rid=5549612&cid=s_37896_77_f&fid=37896&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22194349%26dopt%3DAbstract Authors: Wilf NM, Salmond GP Abstract Serratia sp. ATCC 39006 (S39006) is a Gram-negative bacterium that is virulent in plant (potato) and animal (Caenorhabditis elegans) models. It produces two secondary metabolite antibiotics, a prodigiosin and a carbapenem, and the exoenzymes, pectate lyase and cellulase. We showed previously that deletion of the RNA chaperone Hfq abolished antibiotic production and attenuated virulence in both animal and plant hosts (Wilf et al., 2011). Hfq and dependent sRNAs are known to regulate the post-transcriptional expression of rpoS, which encodes σS, the stationary phase sigma factor subunit of RNA polymerase. An S39006 hfq deletion mutant showed decreased transcript levels of rpoS. Therefore, in this study we investigated whether the phenotypes regu... Microbiology journals http://www.medworm.com/rss/comments.php?id=5549612 Thu, 22 Dec 2011 05:00:00 +0100 5549612 http://www.medworm.com/index.php?rid=5549611&cid=s_37896_77_f&fid=37896&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22194350%26dopt%3DAbstract Authors: Roy M, Khara P, Dutta TK Abstract Polycyclic aromatic hydrocarbons (PAHs) comprise of a group of priority organic pollutants that are toxic and/or carcinogenic. Phenanthrene, the simplest polyaromatic hydrocarbon among recognized priority pollutants, is commonly used as a model compound for the study of PAH biodegradation. Sphingobium sp. strain PNB, capable of degrading phenanthrene as a sole carbon and energy source, was isolated from a municipal waste-contaminated soil sample. A combination of chromatographic and spectrometric analyses, together with oxygen uptake and enzyme activity studies, suggested the presence of phenanthrene degradation pathways in the strain. Identification of metabolites suggested that initial dioxygenation of phenanthrene took place at both 3,4... Microbiology journals http://www.medworm.com/rss/comments.php?id=5549611 Thu, 22 Dec 2011 05:00:00 +0100 5549611 http://www.medworm.com/index.php?rid=5549610&cid=s_37896_77_f&fid=37896&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22194351%26dopt%3DAbstract In this study, we found that the HlyE-derived hemolytic activity of enteropathogenic E. coli (EPEC) O55:H7 can be detected after anaerobic cultivation on a washed blood agar plate (EHX plate) that is used to detect the production of EhxA. We also found that the hemolytic activity of EHEC O157:H7 observed on EHX plates under aerobic and anaerobic growth conditions is derived from EhxA and HlyE, respectively; this differential expression of the two hemolysins occurs at the transcriptional level. Our analysis of 60 E. coli strains of various pathotypes and phylogenies for their repertoires of hemolysin genes, hemolytic phenotypes, and hlyE gene sequences revealed that HlyE activity can generally be detected on EHX plates under anaerobic growth conditions if the gene is intact. Furthermore, ou... Microbiology journals http://www.medworm.com/rss/comments.php?id=5549610 Thu, 22 Dec 2011 05:00:00 +0100 5549610 http://www.medworm.com/index.php?rid=5549609&cid=s_37896_77_f&fid=37896&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22194352%26dopt%3DAbstract Authors: Yu M, Wang J, Tang K, Shi X, Wang S, Zhu W, Zhang X Abstract Pseudoalteromonas flavipulchra JG1 produces a protein PfaP and a range of small molecular compounds with inhibitory activities against Vibrio anguillarum. The PfaP protein was purified from the extracellular products of JG1 by electroelution, and antibacterial activity was observed by the in-gel antibacterial assay. The complete amino acid sequence (694 aa) of PfaP was determined by De novo peptide sequencing and subsequently aligning with the proteome sequence of strain JG1. The calculated molecular mass of PfaP was 77.0 kDa. PfaP was 58% identical to L-lysine oxidase AlpP of P. tunicata D2, and 54% to marinocine antimicrobial protein of Marinomonas mediterranea MMB-1. Five small molecules (compound 1-5) with an... Microbiology journals http://www.medworm.com/rss/comments.php?id=5549609 Thu, 22 Dec 2011 05:00:00 +0100 5549609 http://www.medworm.com/index.php?rid=5549608&cid=s_37896_77_f&fid=37896&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22194353%26dopt%3DAbstract Authors: Nakase M, Nakase Y, Chardwiriyapreecha S, Kakinuma Y, Matsumoto T, Takegawa K Abstract In Schizosaccharomyces pombe, neither intracellular sorting nor ubiquitination of amino acid permeases is well understood. In the present study, we show that intracellular sorting of the amino acid permease Aat1p in S. pombe depends on the presence of a nitrogen source in the growth medium. Under N-sufficient conditions Aat1p appeared to be stably localized at the Golgi apparatus. In contrast, under N-insufficient concentrations, Aat1p was sorted to the plasma membrane. Over time, plasma membrane-localized Aat1p was internalized and sorted to the lumen of the vacuole, where it was degraded. Sorting of Aat1p to the vacuolar lumen was dependent on the ESCRT (endosomal sorting complex requi... Microbiology journals http://www.medworm.com/rss/comments.php?id=5549608 Thu, 22 Dec 2011 05:00:00 +0100 5549608 http://www.medworm.com/index.php?rid=5549607&cid=s_37896_77_f&fid=37896&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22194354%26dopt%3DAbstract Authors: Lanéelle MA, Launay A, Spina L, Marrakchi H, Laval F, Eynard N, Lemassu A, Tropis M, Daffé M, Etienne G Abstract Corynebacterineae are characterized by the presence of long-chain lipids, notably mycolic acids (α-alkyl, β-hydroxy fatty acids), the structures of which are genus-specific. Mycolic acids from two environmental strains, Amycolicicoccus subflavus and Hoyosella altamirensis, were isolated and their structures established using a combination of mass spectrometry analysis, 1H-NMR spectroscopy and chemical degradations. The C2-C3 cleavage of these C30-C36 acids led to 2 fragments: saturated C9-C11 acids and saturated and unsaturated C20-C25 aldehydes. Surprisingly, the fatty acids at the origin of the two fragments constitutive of these mycolic acids were present... Microbiology journals http://www.medworm.com/rss/comments.php?id=5549607 Thu, 22 Dec 2011 05:00:00 +0100 5549607 http://www.medworm.com/index.php?rid=5533848&cid=s_37896_77_f&fid=37896&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22174379%26dopt%3DAbstract Authors: Nannapaneni P, Hertwig F, Depke M, Hecker M, Mäder U, Völker U, Steil L, van Hijum SA Abstract The structure of the SigB-dependent general stress regulon of Bacillus subtilis has previously been characterized by proteomics approaches as well as DNA-array based expression studies. However, comparing the SigB targets published in three major transcriptional profiling studies it is obvious that although each of them identified well above 100 target genes only 67 have commonly been identified in all three studies. These substantial differences can likely be attributed to the different strains, growth conditions, microarray platforms and experimental setups used in the studies. In order to gain a better understanding of the structure of this important regulon, a targeted DNA ... Microbiology journals http://www.medworm.com/rss/comments.php?id=5533848 Thu, 15 Dec 2011 05:00:00 +0100 5533848 http://www.medworm.com/index.php?rid=5533847&cid=s_37896_77_f&fid=37896&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22174380%26dopt%3DAbstract Authors: Khan A, Sarkar D Abstract Mycobacterial persistence has gained a lot of attention with respect to developing novel antitubercular drug, which could drastically reduce the duration of tuberculosis therapy. A better understanding of the physiology of Mycobacterium tuberculosis, and metabolic state of the bacillus during the latent period is primary need to find drug targets against the persistent TB. Recent biochemical and genetic studies of nitrate reduction in mycobacteria have revealed the role of distinct proteins and enzymes involved in the pathway. Differential degree of nitrate reduction among pathogenic and non pathogenic mycobacterial species and its regulation during oxygen and nutrient limitations suggest a link of nitrate reduction pathways with latency. Respirat... Microbiology journals http://www.medworm.com/rss/comments.php?id=5533847 Thu, 15 Dec 2011 05:00:00 +0100 5533847 http://www.medworm.com/index.php?rid=5533846&cid=s_37896_77_f&fid=37896&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22174381%26dopt%3DAbstract In this study, two-dimensional gel electrophoresis combined with matrix-assisted laser desorption/ionization-time of flight mass spectrometry identified a Leptospira interrogans serovar Copenhageni strain Fiocruz L1-130 protein, corresponding to open reading frame (ORF) LIC11848, which undergoes extensive and differential methylation of glutamic acid residues. Immunofluorescence microscopy implicated LIC11848 as a surface-exposed outer membrane protein, prompting the designation OmpL32. Indirect immunofluorescence microscopy of golden Syrian hamster liver and kidney sections revealed expression of OmpL32 during colonization of these organs. Identification of methylated surface-exposed outer membrane proteins, such as OmpL32, provides a foundation for delineating the role of this post-trans... Microbiology journals http://www.medworm.com/rss/comments.php?id=5533846 Thu, 15 Dec 2011 05:00:00 +0100 5533846 http://www.medworm.com/index.php?rid=5533845&cid=s_37896_77_f&fid=37896&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22174382%26dopt%3DAbstract Authors: Li Z, Bouckaert J, Deboeck F, De Greve H, Hernalsteens JP Abstract NAD and NADP function ubiquitously in the metabolism of Escherichia coli K-12. NAD auxotrophy can be rendered by mutation in any of the three genes, nadB, nadA, and nadC. The nadB and nadA genes were defined as anti-virulence loci in Shigella spp., as a mutation (mainly in nadB) disrupting the synthesis of quinolinate is required for virulence. Uropathogenic E. coli (UPEC) isolates, from acute cystitis patients, exhibiting nicotinamide auxotrophy were of serotype O18:K1:H7. E. coli UTI89, the model uropathogenic and O18:K1:H7 strain, requires nicotinamide or quinolinate for growth. A mutation in the nadB gene, encoding L-aspartate oxidase, was shown to be responsible for the nicotinamide-requirement of UTI8... Microbiology journals http://www.medworm.com/rss/comments.php?id=5533845 Thu, 15 Dec 2011 05:00:00 +0100 5533845 http://www.medworm.com/index.php?rid=5533844&cid=s_37896_77_f&fid=37896&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22174383%26dopt%3DAbstract Authors: Yu H, Kim KS Abstract Cytotoxic necrotizing factor 1 (CNF1), a Rho-GTPase activating bacterial toxin has been shown to contribute to E. coli K1 invasion of human brain microvascular endothelial cells (HBMEC), which constitute the blood-brain barrier. CNF1, however, is a cytosolic protein and it remains unclear how CNF1 secretion occurs, contributing to E. coli invasion of HBMEC. In order to investigate the genetic requirement for CNF1 secretion in E. coli K1 strain RS218, we performed mini-Tn5 in vitro mutagenesis and constructed a transposon mutant library of strain NBC, in which β-lactamase was fused to the C-terminal of CNF1 in the chromosome of strain RS218. We identified a transposon mutant (NBC-1E6) that exhibited reduced β-lactamase activity in its culture superna... Microbiology journals http://www.medworm.com/rss/comments.php?id=5533844 Thu, 15 Dec 2011 05:00:00 +0100 5533844 http://www.medworm.com/index.php?rid=5533843&cid=s_37896_77_f&fid=37896&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22174384%26dopt%3DAbstract Authors: Tu WY, Pohl S, Summpunn P, Hering S, Kerstan S, Harwood CR Abstract Bacillus anthracis, the causative agent of anthrax, is exposed to host-mediated antibacterial activities, such as reactive oxygen species (ROS), during the early stages of its disease process. The ability to resist these host-mediated insults is an essential characteristic of a successful pathogen while it is generally assumed that non-pathogenic environmental bacteria succumb to these antimicrobial activities. In order to gain insights into the underlying mechanisms that pathogens use to resist host-mediated oxidative stress, we have compared the oxidative stress responses of B. anthracis and B. subtilis, a well-studied environmental bacterium. Among the four putative catalases encoded by B. anthracis we ... Microbiology journals http://www.medworm.com/rss/comments.php?id=5533843 Thu, 15 Dec 2011 05:00:00 +0100 5533843 http://www.medworm.com/index.php?rid=5533840&cid=s_37896_77_f&fid=37896&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22174385%26dopt%3DAbstract Authors: Bergaust L, van Spanning RR, Frostegård A, Bakken LR Abstract The reductases performing the four steps of denitrification are controlled by a network of transcriptional regulators and ancillary factors responding to intra- and extracellular signals amongst which are oxygen and N-oxides (NO and NO2-). Although many components of the regulatory network have been identified, there are gaps in our understanding of their role(s) in controlling the expression of the various reductases, in particular the environmentally important N2O-reductase (N2OR). We investigated denitrification phenotypes of Paracoccus denitrificans mutants, deficient either in: (i) regulatory proteins (three FNR-type transcriptional regulators NarR, NNR and FnrP, and NirI which is involved in transcription... Microbiology journals http://www.medworm.com/rss/comments.php?id=5533840 Thu, 15 Dec 2011 05:00:00 +0100 5533840 http://www.medworm.com/index.php?rid=5533849&cid=s_37896_77_f&fid=37896&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22160401%26dopt%3DAbstract Authors: Chatfield CH, Mulhern BJ, Viswanathan VK, Cianciotto NP Abstract The Gram-negative bacterium Legionella pneumophila elaborates the siderophore legiobactin. We previously showed that cytoplasmic LbtA helps mediate legiobactin synthesis, inner membrane LbtB promotes export of legiobactin, and outer membrane LbtU acts as the ferrisiderophore receptor. RT-PCR analyses now identified lbtC as an iron-repressed gene that is the final gene in an operon containing lbtA and lbtB. In silico analysis predicted that LbtC is an inner membrane protein that belongs to the major facilitator superfamily (MFS). Although capable of normal growth in standard media, lbtC mutants were defective for growth on iron-deplete agar media. While producing normal levels of legiobactin, lbtC mutants were... Microbiology journals http://www.medworm.com/rss/comments.php?id=5533849 Thu, 08 Dec 2011 05:00:00 +0100 5533849 http://www.medworm.com/index.php?rid=5533852&cid=s_37896_77_f&fid=37896&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22130740%26dopt%3DAbstract Authors: Meza-Cervantez P, González-Robles A, Cárdenas-Guerra RE, Ortega-López J, Saavedra E, Pineda E, Arroyo R Abstract The Trichomonas vaginalis 120 kDa protein adhesin (AP120) is induced under iron-rich conditions and has sequence homology with pyruvate : ferredoxin oxidoreductase A (PFO A), a hydrogenosomal enzyme that is absent in humans. This homology raises the possibility that, like AP120, PFO might be localized to the parasite surface and participate in cytoadherence. Here, the cellular localization and function of PFO that was expressed under various iron concentrations was investigated using a polyclonal antibody generated against the 50 kDa recombinant C-terminal region of PFO A (anti-PFO50). In Western blot assays, this antibody recognized a 120 kDa protein ban... Microbiology journals http://www.medworm.com/rss/comments.php?id=5533852 Thu, 01 Dec 2011 05:00:00 +0100 5533852 http://www.medworm.com/index.php?rid=5533851&cid=s_37896_77_f&fid=37896&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22135097%26dopt%3DAbstract Authors: Reffuveille F, Serror P, Chevalier S, Budin-Verneuil A, Ladjouzi R, Bernay B, Auffray Y, Rince A Abstract Enterococcus faecalis is an opportunistic pathogen responsible for nosocomial infections. Lipoproteins in Gram-positive bacteria are translocated across the plasma membrane and anchored by the fatty acid group. They perform critical roles, with some described as virulence determinants. The aim of this study was to explore the roles of E. faecalis lipoproteins in stress response and virulence. We constructed a mutant affected in the predicted prolipoprotein diacylglyceryl-transferase gene lgt, and examined the role of Lgt in membrane anchoring, growth, stress response and virulence. Inactivation of lgt improved growth in a high concentration of Mn(2+) or under oxidative... Microbiology journals http://www.medworm.com/rss/comments.php?id=5533851 Thu, 01 Dec 2011 05:00:00 +0100 5533851 http://www.medworm.com/index.php?rid=5533850&cid=s_37896_77_f&fid=37896&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22135098%26dopt%3DAbstract This study identified eleven unique E. ictaluri host factors essential for phage infection by screening a transposon mutagenized library of two E. ictaluri strains for phage-resistant mutants. Two mutants were isolated with independent insertions in the ompLC gene that encodes a putative outer membrane porin. Phage binding and efficiency of plaquing (EOP) assays with E. ictaluri EILO, its ompLC mutant and a complemented mutant demonstrated that OmpLC serves as a receptor for phage ΦeiAU and ΦeiDWF adsorption. Comparison of translated OmpLCs from 15 different E. ictaluri strains with varying degrees of phage susceptibility revealed that amino acid variations were clustered on the predicted extracellular loop 8 of OmpLC. Deletion of loop 8 of OmpLC completely abolished phage infectivity in... Microbiology journals http://www.medworm.com/rss/comments.php?id=5533850 Thu, 01 Dec 2011 05:00:00 +0100 5533850 http://www.medworm.com/index.php?rid=5533857&cid=s_37896_77_f&fid=37896&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22117004%26dopt%3DAbstract Authors: Spence SA, Clark VL, Isabella VM Abstract We have reported that N. gonorrhoeae is extremely resistant to reactive nitrogen species (RNS) including peroxynitrite (PN). Recent literature suggests that catalase can provide protection against commercial preparations of PN. Though wild type gonococci were shown to be highly resistant to 2mM PN, N. meningitidis and a gonococcal katA mutant were both shown to be extremely sensitive to 2mM PN. Analysis of translational fusions of the catalase promoters from N. gonorrhoeae and N. meningitidis to lacZ demonstrated that basal katA expression from gonococci is 80-fold higher than in meningococci, though meningococcal katA retains a greater capacity to be activated by OxyR. This activation capacity was shown to be due to a single base ... Microbiology journals http://www.medworm.com/rss/comments.php?id=5533857 Thu, 24 Nov 2011 05:00:00 +0100 5533857 http://www.medworm.com/index.php?rid=5533856&cid=s_37896_77_f&fid=37896&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22117005%26dopt%3DAbstract Authors: Teixeira N, Santos S, Marujo P, Yokohata R, Iyer VS, Nakayama J, E Hancock L, Serror P, Lopes MD Abstract The concomitant presence of complete fsr quorum-sensing system and gelE-sprE operons in Enterococcus faecalis is known to be essential for the detection of gelatinase activity. However, there are reports stating the absence of gelatinase activity despite the presence of complete fsr and gelE loci. In order to understand this incongruence between genotype and phenotype we sequenced fsr and gelE loci of E. faecalis LN68 strain, which was previously found to carry both operons but to lack gelatinase activity. Of the 59 nucleotide differences detected compared to the gelatinase positive V583 strain, we found a nonsense mutation (a premature STOP codon) predicted to truncat... Microbiology journals http://www.medworm.com/rss/comments.php?id=5533856 Thu, 24 Nov 2011 05:00:00 +0100 5533856 http://www.medworm.com/index.php?rid=5533855&cid=s_37896_77_f&fid=37896&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22117006%26dopt%3DAbstract In this study, we used a protein-binding microarray (PBM) to discover the DNA recognition sites and putative regulons for three TetR and one MarR family TFs derived from B. xenovorans, which are common to the Burkholderia genus. We also describe the development and application of a more streamlined version of the PBM technology that significantly reduced the experimental time. Despite containing many pathogenically important species, only a handful of TF operator sites have been experimentally characterized for Burkholderia to date. Our study provides a significant addition to this knowledge base and illustrates some general challenges of discovering operators on a large scale for prokaryotes. PMID: 22117006 [PubMed - as supplied by publisher] (Source: Microbiology) Microbiology journals http://www.medworm.com/rss/comments.php?id=5533855 Thu, 24 Nov 2011 05:00:00 +0100 5533855 http://www.medworm.com/index.php?rid=5533854&cid=s_37896_77_f&fid=37896&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22117007%26dopt%3DAbstract Authors: Singh B, Singh HB, Singh A, Singh B, Mishra A, Nautiyal C Abstract Lagerstroemia speciosa (Lythraceae), a Southeast Asian tree is more commonly known as "Jarul". Research on health benefits suggests that L. speciosa plant contains phytomolecules which may act as antioxidant, anti-diabetic and anti-obesity. However, antimicrobial activities of this plant are not reported. Potential of L. speciosa fruit extract (LSFE) was evaluated to antagonize cell to cell communication, expression of virulence genes and factors and biofilm formation in Pseudomonas aeruginosa strain PAO1. Our results suggested that the LSFE caused downregulation of the quorum sensing (QS) related genes (las & rhl) and their respective signaling molecules AHLs, without affecting growth of P. aeruginosa ... Microbiology journals http://www.medworm.com/rss/comments.php?id=5533854 Thu, 24 Nov 2011 05:00:00 +0100 5533854 http://www.medworm.com/index.php?rid=5533853&cid=s_37896_77_f&fid=37896&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22117008%26dopt%3DAbstract Authors: Hare J, Bradley J, Lin CL, Elam T Abstract Error-prone and error-free DNA damage repair responses that are induced in most bacteria after exposure to various chemicals, antibiotics, or radiation sources were surveyed across the Acinetobacter genus. The error prone SOS mutagenesis response occurs when DNA damage induces a cell's umuDC- or dinP-encoded error-prone polymerases. The model Acinetobacter baylyi strain ADP1 possesses an unusual, regulatory umuD allele (umuDAb) with an extended 5' region, and only incomplete fragments of umuC. Diverse Acinetobacter species were investigated for the type and presence of umuDC and their ability to conduct UV-induced mutagenesis. Unlike ADP1, most Acinetobacter strains possessed multiple umuD-umuC loci containing either umuDAb or an ... Microbiology journals http://www.medworm.com/rss/comments.php?id=5533853 Thu, 24 Nov 2011 05:00:00 +0100 5533853 http://www.medworm.com/index.php?rid=5439917&cid=s_37896_77_f&fid=37896&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22096146%26dopt%3DAbstract Authors: Baker SE, Perrone G, Richardson NM, Gallo A, Kubicek CP Abstract Members of the economically important ascomycete genus Trichoderma are ubiquitously distributed around the world. The mycoparasitic lifestyle and plant defense inducing interactions of Trichoderma spp. make them ideal biocontrol agents. Of the Trichoderma enzymes that produce secondary metabolites, some of which likely play important roles in biocontrol processes, polyketide synthases have garnered less attention that non-ribosomal peptide synthetases such as those that produce peptaibols. We have taken a phylogenomic approach to study the polyketide synthase repertoire encoded in the genomes of Trichoderma reesei, Trichoderma atroviride and Trichoderma virens. Our analysis lays a foundation for future resear... Microbiology journals http://www.medworm.com/rss/comments.php?id=5439917 Thu, 17 Nov 2011 05:00:00 +0100 5439917 http://www.medworm.com/index.php?rid=5439916&cid=s_37896_77_f&fid=37896&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22096147%26dopt%3DAbstract Authors: Pinto F, van Elburg KA, Pacheco CC, Lopo M, Noirel J, Montagud A, Urchueguía JF, Wright PC, Tamagnini P Abstract Cyanobacteria are photosynthetic prokaryotes that are promising "low-cost" microbial cell factories due to their simple nutritional requirements, metabolic plasticity, and availability of tools for their genetic manipulation. The unicellular non-nitrogen fixing Synechocystis sp. PCC 6803 is the best studied cyanobacterial strain and its genome was the first to be sequenced. The vast amount of physiological and molecular data available, together with a relative small genome, makes Synechocystis suitable for computational metabolic modeling and to be used as a photoautotrophic chassis in synthetic biology applications. To prepare it for the introduction of a synt... Microbiology journals http://www.medworm.com/rss/comments.php?id=5439916 Thu, 17 Nov 2011 05:00:00 +0100 5439916 http://www.medworm.com/index.php?rid=5439915&cid=s_37896_77_f&fid=37896&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22096148%26dopt%3DAbstract Authors: Ul-Hassan SR, Strobel GA, Booth E, Knighton B, Floerchinger C, Sears J Abstract ABSTRACTAn endophytic Hypoxylon sp. (CI-4) producing a wide spectrum of volatile organic compounds (VOCs) including 1, 8-cineole and 1-methyl-1,4-cyclohexadiene, and cyclohexane, 1,2,4-tris (methylene) was selected as a candidate for epigenetic modulation. This was done in order to learn if epigenetic expression for these and other volatile compounds can be modulated. Many of the compounds made by this organism are of interest because of their high energy densities and thus the potential they might have as Mycodiesel fuels. The fungus was exposed to the epigenetic modulators- histone deacetylase- and a DNA methyltransferase inhibitor -SAHA (suberoylanilide hydroxamic acid) as well as 5-azacytid... Microbiology journals http://www.medworm.com/rss/comments.php?id=5439915 Thu, 17 Nov 2011 05:00:00 +0100 5439915 http://www.medworm.com/index.php?rid=5439914&cid=s_37896_77_f&fid=37896&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22096149%26dopt%3DAbstract Authors: Hackenberg C, Huege J, Engelhardt A, Wittink F, Laue M, Matthijs HC, Kopka J, Bauwe H, Hagemann M Abstract Using metabolic and transcriptomic phenotyping, we studied acclimation of cyanobacteria to low-carbon (LC) conditions and the requirements for coordinated alteration of metabolism and gene expression. To analyze possible metabolic signals for LC sensing and compensating reactions, the carboxysome-less mutant ΔccmM and the photorespiratory mutant ΔglcD1/D2 were compared with wild-type (WT) Synechocystis. Metabolic phenotyping revealed accumulation of 2-phosphoglycolate (2PG) in ΔccmM and of glycolate in ΔglcD1/D2 in LC but also in high-carbon (HC) grown mutant cells. The accumulation of photorespiratory metabolites provided evidence for oxygenase activity of RubisC... Microbiology journals http://www.medworm.com/rss/comments.php?id=5439914 Thu, 17 Nov 2011 05:00:00 +0100 5439914 http://www.medworm.com/index.php?rid=5439913&cid=s_37896_77_f&fid=37896&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22096150%26dopt%3DAbstract This study investigated the expression profiles of single and double isogenic lysogens of Stx-phage Φ24B using qRT-PCR to examine transcription levels and a reporter gene construct as a proxy for the translation levels of stx transcripts. Toxin gene expression in double lysogens was in excess of its single lysogen counterpart, in both the prophage state and after induction of the lytic life cycle. In addition, double lysogens were found to be more sensitive to an increased induction stimulus than single lysogens, suggesting that maintenance of a stable prophage is less likely when multiple phage genome copies are present. Overall, these data demonstrate that the phenomenon of multiple lysogeny in STEC has the potential to impact upon disease pathology through increased toxin load. PMI... Microbiology journals http://www.medworm.com/rss/comments.php?id=5439913 Thu, 17 Nov 2011 05:00:00 +0100 5439913 http://www.medworm.com/index.php?rid=5439912&cid=s_37896_77_f&fid=37896&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22096151%26dopt%3DAbstract Authors: Orchard SS, Rostron JE, Segall AM Abstract The peptide wrwycr inhibits Holliday junction resolution and is a potent antimicrobial. To study the physiological effects of wrwycr treatment on Escherichia coli cells, we partially screened the Keio collection of knockout mutants for those with increased sensitivity to wrwycr. Strains lacking part of the ferric-enterobactin (iron-bound siderophore) uptake and utilization system, parts of the enterobactin synthesis pathway, TolC (an outer-membrane channel protein), or Fur (an iron-responsive regulator) were hypersensitive to wrwycr. We provide evidence that the tolC mutant was hypersensitive to wrwycr because it had reduced ability to efflux wrwycr from the cell rather than due to its export of newly-synthesized enterobactin. Del... Microbiology journals http://www.medworm.com/rss/comments.php?id=5439912 Thu, 17 Nov 2011 05:00:00 +0100 5439912 http://www.medworm.com/index.php?rid=5439911&cid=s_37896_77_f&fid=37896&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22096152%26dopt%3DAbstract In conclusion, operating the BEC under 75-500 mV enables a pure culture of Pseudomonas putida F1 growth and toluene degradation even in an oxygen-limited environment. PMID: 22096152 [PubMed - as supplied by publisher] (Source: Microbiology) Microbiology journals http://www.medworm.com/rss/comments.php?id=5439911 Thu, 17 Nov 2011 05:00:00 +0100 5439911 http://www.medworm.com/index.php?rid=5419419&cid=s_37896_77_f&fid=37896&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22075022%26dopt%3DAbstract In this study, a Tn5-tagged mutant library of Xoc strain RS105 was screened on rice, and 27 Tn5 mutants were identified that were either nonpathogenic or showed reduced virulence in rice. Fourteen of the nonpathogenic mutants were also unable to elicit the hypersensitive response (HR) in tobacco and were designated Pth-/HR- mutants; thirteen mutants showed attenuated virulence and were able to induce an HR (Vir-/HR+). Sequence analysis of the Tn5-tagged genes indicated that the 14 Pth-/HR- mutants included mutations in hrcC, hrcT, hrcV, hpaP, hrcQ, hrpF, hrpG and hrpX. The 13 Vir-/HR+ mutants included tal-C10c-like (a transcriptional activator-like TAL effector), rpfC (regulator of pathogenicity factors), oxyR (oxidative stress transcriptional regulator), dsbC (disulfide isomerase), opgH (... Microbiology journals http://www.medworm.com/rss/comments.php?id=5419419 Thu, 10 Nov 2011 05:00:00 +0100 5419419 http://www.medworm.com/index.php?rid=5419418&cid=s_37896_77_f&fid=37896&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22075023%26dopt%3DAbstract Authors: Omann MR, Lehner S, Escobar Rodriguez C, Brunner K, Zeilinger S Abstract Mycoparasitic Trichoderma species are applied as biocontrol agents in agriculture to guard plants against fungal diseases. During mycoparasitism, Trichoderma directly interacts with phytopathogenic fungi preceded by a specific recognition of the host and resulting in its disarming and killing. In various fungal pathogens including mycoparasites, signaling via heterotrimeric G protein plays a major role in regulating pathogenicity-related functions. Nevertheless, the corresponding receptors involved in the recognition of host-derived signals are largely unknown. Functional characterization of T. atroviride Gpr1 revealed a prominent role of this seven-transmembrane protein of the cAMP receptor-like fami... Microbiology journals http://www.medworm.com/rss/comments.php?id=5419418 Thu, 10 Nov 2011 05:00:00 +0100 5419418 http://www.medworm.com/index.php?rid=5419417&cid=s_37896_77_f&fid=37896&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22075024%26dopt%3DAbstract Authors: Pina-Pedrero S, Olvera A, Pérez-Simó M, Bensaid A Abstract The genome of the highly pathogenic Haemophilus parasuis Nagasaki strain (serovar 5) was sequenced in the 99%. A genomic comparison with two other pathogenic serovar 5 H. parasuis strains identified six genes per genome (bmaA1 to bmaA6) coding for beta-barrel monomeric autotransporters, bmaA2 and bmaA3 being pseudogenes in at least one strain. The remaining encoding proteins were predicted to belong to the subtilisin (BmaA1 and BmaA4) and cysteine (BmaA5 and BmaA6) protease families respectively. Allelic polymorphism was detected in other H. parasuis strains by comparative genomic hybridisation using microarrays. Recombination events were observed, some of them leading to gene disruption in one of the three strai... Microbiology journals http://www.medworm.com/rss/comments.php?id=5419417 Thu, 10 Nov 2011 05:00:00 +0100 5419417 http://www.medworm.com/index.php?rid=5419416&cid=s_37896_77_f&fid=37896&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22075025%26dopt%3DAbstract Authors: Friedl MA, Druzhinina IS Abstract In this paper we report on the in situ diversity of the mycotrophic fungus Trichoderma (teleomorph Hypocrea, Ascomycota, Dikarya) revealed by a taxon-specific metagenomic approach. We designed a set of genus-specific ITS1 and 2 rRNA primers and constructed a clone library containing 411 molecular operational taxonomic units (MOTUs). The overall species composition in soils of the two distinct ecosystems of the Danube floodplain consisted of 15 known species and 2 potentially new taxa. The latter taxa accounted only for 1.5 % of all MOTUs, suggesting that almost no hidden or uncultivable Hypocrea/Trichoderma species is present at least in these temperate forest soils. The species were unevenly distributed in vertical soil profiles although ... Microbiology journals http://www.medworm.com/rss/comments.php?id=5419416 Thu, 10 Nov 2011 05:00:00 +0100 5419416 http://www.medworm.com/index.php?rid=5419415&cid=s_37896_77_f&fid=37896&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22075026%26dopt%3DAbstract Fumarate Reductase is a Major Contributor to the Generation of Reactive Oxygen Species in the Anaerobe Bacteroides fragilis. Microbiology. 2011 Nov 10; Authors: Meehan BM, Malamy MH Abstract Despite the catastrophic role that endogenously-generated reactive oxygen species (ROS) may play in bacteria exposed to aerobic environments, very few sources of ROS have been identified in vivo. Such studies are often precluded by the presence of efficient ROS scavenging pathways, like those found in the aerotolerant anaerobe, Bacteroides fragilis. Here we demonstrate that deletion of the genes encoding catalase (Kat), alkylhydroperoxide reductase (AhpC), and thioredoxin-dependent peroxidase (Tpx) strongly inhibits H2O2 detoxification in B. fragilis, thereby allowing for the quantifica... Microbiology journals http://www.medworm.com/rss/comments.php?id=5419415 Thu, 10 Nov 2011 05:00:00 +0100 5419415 http://www.medworm.com/index.php?rid=5419414&cid=s_37896_77_f&fid=37896&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22075027%26dopt%3DAbstract Authors: Mukherjee P, Buensanteai N, Moran-Diez M, Druzhinina I, Kenerley C Abstract Trichoderma virens genome harbors genes encoding 22 non-ribosomal peptide synthetases (NRPSs) with at least one complete module (containing adenylation, thiolation and condensation domains), and four PKS/NRPS (polyketide synthase/NRPS) hybrid enzymes. After a primary screen for expression of these 26 genes when mycelia of T. virens are in contact with maize roots, seven genes that are up-regulated were selected for further study. Using homologous recombination, loss-of-function mutants in six of these were obtained (the seventh, tex2, was acquired from our previous studies). Plant assays in a hydroponics system revealed that all seven mutants retained the ability to internally colonize maize roots.... Microbiology journals http://www.medworm.com/rss/comments.php?id=5419414 Thu, 10 Nov 2011 05:00:00 +0100 5419414 http://www.medworm.com/index.php?rid=5419413&cid=s_37896_77_f&fid=37896&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22075028%26dopt%3DAbstract Authors: Vockenhuber MP, Suess B Abstract Transcriptional regulation of primary and secondary metabolism is well-studied in Streptomyces coelicolor, a model organism for antibiotics production and cell differentiation. In contrast, little is known about post-transcriptional regulation and the potential functions of small non-coding RNAs (sRNAs) in this Gram-positive, GC-rich soil bacterium. Here, we report the identification and characterization of scr5239, a sRNA highly conserved in the genus of Streptomyces. The sRNA is 159 nt long, composed of five stem-loops and encoded in the intergenic region between SCO5238 and SCO5239. scr5239 expression is constitutive under several stress and growth conditions but dependent on the nitrogen supply. scr5239 decreases the production of the a... Microbiology journals http://www.medworm.com/rss/comments.php?id=5419413 Thu, 10 Nov 2011 05:00:00 +0100 5419413 http://www.medworm.com/index.php?rid=5419412&cid=s_37896_77_f&fid=37896&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22075029%26dopt%3DAbstract Authors: Rubio MB, Domínguez S, Monte E, Hermosa R Abstract Trichoderma spp. are widely used as biopesticides and biofertilizers to control diseases and to promote positive physiological responses in plants. In vitro and in vivo assays carried out with T. harzianum CECT 2413 (T34), T. virens Gv29-8 (T87) and T. hamatum IMI 224801 (T7) revealed that strains affected the growth and development of lateral roots in tomato plants in different ways. The early expression profiles of these Trichoderma strains were studied after 20 h of incubation in the presence of tomato plants, using a high-density oligonucleotide (HDO) microarray, with the aim of comparing the transcriptional changes of these three strains in response to the presence/absence of the plant. As a result, 1,077 (3.15%) out... Microbiology journals http://www.medworm.com/rss/comments.php?id=5419412 Thu, 10 Nov 2011 05:00:00 +0100 5419412 http://www.medworm.com/index.php?rid=5419411&cid=s_37896_77_f&fid=37896&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22075030%26dopt%3DAbstract Authors: Dorkhan M, Chávez de Paz LE, Skepö M, Svensater G, Davies JR Abstract The use of dental implants to treat tooth loss has increased rapidly over recent years. 'Smooth' implants showing high long-term success rates have successively been replaced by implants with rougher surfaces, designed to stimulate rapid osseointegration and promote tissue healing. If exposed in the oral cavity, rougher surfaces may promote bacterial adhesion leading to formation of microbial biofilms which can induce peri-implant inflammation. Streptococcus oralis is an early colonizer of oral surfaces and has been recovered from titanium surfaces in vivo. The purpose of this study was to examine the adherence of clinical strains of S. oralis to titanium with smooth or moderately rough surface topogra... Microbiology journals http://www.medworm.com/rss/comments.php?id=5419411 Thu, 10 Nov 2011 05:00:00 +0100 5419411 http://www.medworm.com/index.php?rid=5419410&cid=s_37896_77_f&fid=37896&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22075031%26dopt%3DAbstract Authors: Awasthy D, Bharath S, Subbulakshmi V, Sharma UK Abstract Alanine racemase (Alr) is an essential enzyme in most bacteria, however some species (e.g. L. monocytogenes) can utilise D-amino acid transaminase (Dat) for generating D-alanine, which renders Alr non-essential. In addition to the conflicting reports on gene knockout of alr in M. smegmatis, a recent study concluded that depletion of Alr does not affect the growth of M. smegmatis. In order to get an unambiguous answer on the essentiality of Alr in M. tuberculosis and validate it as a drug target in-vitro and in-vivo, we have inactivated the alr gene of M. tuberculosis and found that it was not possible to generate an alr knockout in the absence of a complementing gene copy or D-alanine in the growth medium. The growth... Microbiology journals http://www.medworm.com/rss/comments.php?id=5419410 Thu, 10 Nov 2011 05:00:00 +0100 5419410 http://www.medworm.com/index.php?rid=5379554&cid=s_37896_77_f&fid=37896&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22053003%26dopt%3DAbstract Authors: Sandh G, Xu L, Bergman B Abstract The establishment of non-diazotrophic cultures of the filamentous marine cyanobacterium Trichodesmium erythraeum IMS101 enabled the first detailed investigation of the process leading to the development of its unique nitrogen-fixing cell type, the diazocyte. Trichome heterogeneity was apparent already within 3-8h, while the differentiation of mature diazocytes, containing the nitrogenase enzyme, required 27 h after the removal of combined nitrogen. The distribution of "pro-diazocytes" within the trichomes correlates with the localization of mature diazocytes which suggests that pattern regulation is an early event during diazocyte development. The development of diazocytes was initially identified as changes in the subcellular ultrastructu... Microbiology journals http://www.medworm.com/rss/comments.php?id=5379554 Thu, 03 Nov 2011 04:00:00 +0100 5379554 http://www.medworm.com/index.php?rid=5379553&cid=s_37896_77_f&fid=37896&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22053004%26dopt%3DAbstract Authors: Kruczek C, Wachtel M, Alabady MS, Payton PR, Colmer-Hamood JA, Hamood AN Abstract Pseudomonas aeruginosa, which causes serious infections in immunocompromised patients, produces numerous virulence factors including exotoxin A and the siderophore pyoverdine. As production of these virulence factors is influenced by the host environment, we examined the effect serum has on global transcription within the P. aeruginosa strain PAO1 at different phases of growth in an iron-deficient medium. At early exponential phase, serum significantly enhanced expression of 138 genes, most repressed by iron including pvdS, regA, and the pyoverdine synthesis genes. However, serum does not interfere with the repression of these genes by iron. Serum enhanced regA expression in a fur mutant of ... Microbiology journals http://www.medworm.com/rss/comments.php?id=5379553 Thu, 03 Nov 2011 04:00:00 +0100 5379553 http://www.medworm.com/index.php?rid=5379552&cid=s_37896_77_f&fid=37896&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22053005%26dopt%3DAbstract Authors: Ma Y, Luo Y, Huang X, Song F, Liu G Abstract We sought to develop Bifidobacterium infantis (BI) as a vehicle for the expression of heterologous antigens. Two proteins of enterotoxigenic Escherichia coli (ETEC) have been expressed in BI: CfaB, a major fimbrial subunit protein, and LTB, the B subunit of heat-labile enterotoxin. The expression of each CfaB and LTB protein in BI was verified by electrophoresis analysis. SD rats were then subjected to intragastric immunization with BI-CfaB and BI-LTB systems both separately and together. ELISA was used to characterize the serum and mucosal immune responses against ETEC antigens. The immunized rats were intraperitoneally challenged with wild-type ETEC H10407 to study the immune response in vivo. The serum titers of IgG and fecal... Microbiology journals http://www.medworm.com/rss/comments.php?id=5379552 Thu, 03 Nov 2011 04:00:00 +0100 5379552 http://www.medworm.com/index.php?rid=5379551&cid=s_37896_77_f&fid=37896&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22053006%26dopt%3DAbstract In this study, we first demonstrated that Trichokonin VI (TK VI) induced extensively apoptotic programmed cell death (PCD) in plant fungal pathogens. For a deeper insight into the apoptotic mechanism involved in TK VI, Fusarium oxysporum was used as a model to detail the process. The cells of F. oxysporum treated with TK VI showed apoptotic hallmarks, such as exposure of phosphatidylserine, the appearance of reactive oxygen species (ROS) and fragmentation of nuclear DNA. Moreover, TK VI -treated cells exhibited an accumulation of cytoplasmic vacuoles with loss of the mitochondrial transmembrane potential and this process was independent of metacaspases. Therefore, TK VI induced metacaspase-independent apoptotic cell death in F. oxysporum. This represents the first report to reveal the anti... Microbiology journals http://www.medworm.com/rss/comments.php?id=5379551 Thu, 03 Nov 2011 04:00:00 +0100 5379551 http://www.medworm.com/index.php?rid=5379550&cid=s_37896_77_f&fid=37896&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22053007%26dopt%3DAbstract Authors: Tom SK, Callahan SM Abstract The filamentous cyanobacterium Anabaena sp. strain PCC 7120 differentiates nitrogen-fixing heterocysts arranged in a periodic pattern when deprived of a fixed source of nitrogen. In a genetic screen for mutations that prevent diazotrophic growth, open reading frame all1758, which encodes a putative serine/threonine phosphatase, was identified. Mutation of all1758 resulted in a number of seemingly disparate phenotypes that included a delay in the morphological differentiation of heterocysts, reduced cell size, and lethality under certain conditions. The mutant was incapable of fixing nitrogen under both oxic and anoxic conditions, and lacked the minor heterocyst-specific glycolipid. Pattern formation, as indicated by the timing and pattern of ex... Microbiology journals http://www.medworm.com/rss/comments.php?id=5379550 Thu, 03 Nov 2011 04:00:00 +0100 5379550 http://www.medworm.com/index.php?rid=5379549&cid=s_37896_77_f&fid=37896&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22053008%26dopt%3DAbstract Authors: Metz S, Jager A, Klug G Abstract The facultatively photosynthetic bacterium Rhodobacter sphaeroides harbors an unusual LOV (light, oxygen, voltage) domain protein, RsLOV. While showing a characteristic photocycle, the protein misses a C-terminal output domain, similar to PpSB2 in Pseudomonas putida. Oxygen tension and light quantity are the two main responsible factors controlling the expression of photosynthesis genes in Rhodobacter sphaeroides. Two photoreceptor proteins are known to be involved in this regulation: the intensively studied AppA protein and the more recently identified cryptochrome-like protein CryB. Here we show by transcriptome and physiological studies that RsLOV is also involved in the regulation of photosynthetic gene expression. Our data further hint... Microbiology journals http://www.medworm.com/rss/comments.php?id=5379549 Thu, 03 Nov 2011 04:00:00 +0100 5379549 http://www.medworm.com/index.php?rid=5379548&cid=s_37896_77_f&fid=37896&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22053009%26dopt%3DAbstract Authors: Saloheimo M, Pakula TM Abstract Trichoderma reesei (Hypocrea jecorina) is an efficient cell factory for protein production exploited by the enzyme industry. Yields of over 100 g/l of secreted protein from industrial fermentations have been reported. In this review we discuss the spectrum of proteins secreted by T. reesei and the studies carried out on its protein secretion system. The major enzymes secreted by T. reesei under production conditions are those degrading plant polysaccharides, the most dominant ones being the major cellulases, as demonstrated by the 2D gel analysis of the secretome. According to genome analysis, T. reesei has fewer genes encoding enzymes involved in plant biomass degradation as compared to other fungi with sequenced genomes. We discuss also ot... Microbiology journals http://www.medworm.com/rss/comments.php?id=5379548 Thu, 03 Nov 2011 04:00:00 +0100 5379548 http://www.medworm.com/index.php?rid=5379557&cid=s_37896_77_f&fid=37896&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22034485%26dopt%3DAbstract In conclusion, we identified two new naturally-occurring point-mutations leading to the non-typeability in pneumococcus and demonstrated that WchA is essential for the biosynthesis of the serotype 7F capsule. PMID: 22034485 [PubMed - as supplied by publisher] (Source: Microbiology) Microbiology journals http://www.medworm.com/rss/comments.php?id=5379557 Thu, 27 Oct 2011 04:00:00 +0100 5379557 http://www.medworm.com/index.php?rid=5379556&cid=s_37896_77_f&fid=37896&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22034486%26dopt%3DAbstract Authors: Sharma SK, Moe TS, Srivastava R, Chandra D, Srivastava BS Abstract Authors' response: on sialic acid transport and utilization by Vibrio cholerae. PMID: 22034486 [PubMed - as supplied by publisher] (Source: Microbiology) Microbiology journals http://www.medworm.com/rss/comments.php?id=5379556 Thu, 27 Oct 2011 04:00:00 +0100 5379556 http://www.medworm.com/index.php?rid=5379555&cid=s_37896_77_f&fid=37896&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22034487%26dopt%3DAbstract Authors: Fivian-Hughes A, Houghton J, Davis E Abstract Thymidylate synthase (TS) enzymes catalyse the biosynthesis of deoxythymidine monophosphate (dTMP), and so are important for DNA replication and repair. Two different types of TS proteins have been described (ThyA and ThyX), which have different enzymatic mechanisms and unrelated structures. Mycobacteria are unusual as they encode both thyA and thyX, and the biological significance of this is not yet understood. Mycobacterium tuberculosis ThyX is thought to be essential and a potential drug target. We therefore analysed M. tuberculosis thyA and thyX expression levels, their essentiality and roles in pathogenesis. We show that both thyA and thyX are expressed in vitro, and this expression significantly increased within murine ma... Microbiology journals http://www.medworm.com/rss/comments.php?id=5379555 Thu, 27 Oct 2011 04:00:00 +0100 5379555 http://www.medworm.com/index.php?rid=5344657&cid=s_37896_77_f&fid=37896&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22016565%26dopt%3DAbstract Authors: Juntachai W, Oura T, Kajiwara S Abstract Malassezia globosa is a lipid-dependent yeast that is found on the human skin and associated with various skin disorders, including dandruff and seborrhoeic dermatitis (SD). Despite its important role in skin diseases, the molecular basis for its pathogenicity is poorly understood. The current hypothesis is that dandruff and SD is linked to fatty acid metabolism and secretory lipolytic enzymes, which hydrolyze sebaceous lipids and release irritating free fatty acids. A previous genomic analysis identified 13 secreted lipase gene homologues of M. globosa. We have also reported that M. globosa had significantly higher extracellular lipase activity compared to other species. To identify the major secretory lipases of this yeast during ... Microbiology journals http://www.medworm.com/rss/comments.php?id=5344657 Thu, 20 Oct 2011 04:00:00 +0100 5344657 http://www.medworm.com/index.php?rid=5344656&cid=s_37896_77_f&fid=37896&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22016566%26dopt%3DAbstract We describe here the results of our studies into the quorum-sensing system in Halomonas anticariensis FP35T, which is composed of luxR/luxI homologues: hanR (the putative transcriptional regulator gene) and hanI (the autoinducer synthase gene). To understand how the hanR/hanI system is organised and regulated we conducted RT-PCR and quantitative real-time PCR assays. Transcriptional analysis indicated that the hanR and hanI genes are on the same transcript and their transcription is growth-phase dependent. HanI seems to be the only autoinducer synthase responsible for the synthesis of AHLs by the bacterium since the inactivation of hanI resulted in the complete loss of its AHLs. We also found that the hanI gene appears to be transcribed from its own promoter and its expression does not dep... Microbiology journals http://www.medworm.com/rss/comments.php?id=5344656 Thu, 20 Oct 2011 04:00:00 +0100 5344656 http://www.medworm.com/index.php?rid=5344655&cid=s_37896_77_f&fid=37896&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22016567%26dopt%3DAbstract Authors: Vorapreeda T, Thammarongtham C, Cheevadhanarak S, Laoteng K Abstract For a bio-based economy, microbial lipids offer a potential solution as alternatives for feedstock in the oleochemical industry. The existing genome data for the promising strains, oleaginous yeasts and fungi, allowed us to investigate the candidate orthologous sequences participating in their oleaginicity. Comparative genome analysis of the non-oleaginous (Saccharomyces cerevisiae, Candida albicans and Ashbya gossypii) and oleaginous strains (Yarrowia lipolytica, Rhizopus oryzae, Aspergillus oryzae, and Mucor circinelloides) showed that 209 orthologous protein sequences of the oleaginous microbes were distributed over several processes of the cells. Based on the 41 sequences categorised by metabolism, pu... Microbiology journals http://www.medworm.com/rss/comments.php?id=5344655 Thu, 20 Oct 2011 04:00:00 +0100 5344655 http://www.medworm.com/index.php?rid=5344654&cid=s_37896_77_f&fid=37896&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22016568%26dopt%3DAbstract Authors: Manuel J, Selin C, Fernando D, de Kievit T Abstract The stringent response (SR) is a regulatory mechanism that enables bacteria to adapt to nutrient stress through the production of the alarmone (p)ppGpp. The aim of the current study was to understand how the SR affects the antifungal (AF) activity of Pseudomonas chlororaphis PA23. Two SR mutants were generated, PA23relA and PA23relAspoT, that no longer produced (p)ppGpp. Both mutants exhibited increased inhibition of Sclerotinia sclerotiorum in vitro and elevated pyrrolnitrin (PRN), lipase and protease production. Phenazine (PHZ) levels, on the other hand, remained unchanged. Through transcriptional fusion analysis we discovered that prnA-lacZ (PRN) activity was increased in the SR mutants; whereas phzA-lacZ (PHZ) activit... Microbiology journals http://www.medworm.com/rss/comments.php?id=5344654 Thu, 20 Oct 2011 04:00:00 +0100 5344654 http://www.medworm.com/index.php?rid=5344653&cid=s_37896_77_f&fid=37896&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22016569%26dopt%3DAbstract Authors: Alvarez-Ordóñez A, Begley M, Prito M, Messens W, López M, Bernardo A, Hill C Abstract Human salmonellosis infections are usually acquired via the food chain as a result of the ability of Salmonella serovars to colonize and persist within the gastrointestinal tract of their hosts. In addition, after food ingestion and in order to cause the foodborne disease in humans, Salmonella must be able to resist to several deleterious stress conditions which are part of the host defense against infections. This review gives an overview of the main defensive mechanisms involved in Salmonella response to the extreme acid conditions of the stomach, and the elevated concentrations of bile salts, osmolytes, commensal bacterial metabolites and low oxygen tension conditions of the mammali... Microbiology journals http://www.medworm.com/rss/comments.php?id=5344653 Thu, 20 Oct 2011 04:00:00 +0100 5344653 http://www.medworm.com/index.php?rid=5344652&cid=s_37896_77_f&fid=37896&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22016570%26dopt%3DAbstract This report presents results of the first study of a histone acetyltransferase in a Leishmania species. The HAT4 gene of Leishmania donovani, the causative pathogen of Visceral Leishmaniasis, has been cloned and expressed in fusion with GFP in Leishmania promastigotes. We find that HAT4-GFP behaves differently from typical eukaryotic MYST family HATs that are usually constitutively nuclear, in that it is cytosolic throughout the cell cycle, though the protein is also present in the nucleus in post-mitotic cells. Substrate specificity analyses reveal that LdHAT4 acetylates the N-terminus of histone H4, but not of H2A, H2B or H3. Nor does it acetylate the C-terminus of H2A. The primary target of HAT4-mediated acetylation is the K14 residue of H4, though K2 might be a minor site as well. H4K1... Microbiology journals http://www.medworm.com/rss/comments.php?id=5344652 Thu, 20 Oct 2011 04:00:00 +0100 5344652 http://www.medworm.com/index.php?rid=5344651&cid=s_37896_77_f&fid=37896&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22016571%26dopt%3DAbstract We describe a hybrid transcriptomic and modelling analysis of the dynamics of a bacterial response to stress, namely the addition of 200 μM Zn to Escherichia coli growing in severely Zn-depleted medium and of cells growing at different Zn concentrations at steady state. Genes that changed significantly in response to the transition were those reported previously to be associated with zinc deficiency (zinT, znuA, ykgM) or excess (basR, cpxP, cusF). Cellular Zn levels were confirmed by ICP-AES to be 14- to 28-fold greater after Zn addition but there was also 6- to 8-fold more cellular Fe 30 min after Zn addition. Statistical modelling of the the transcriptomic data generated from the Zn shift focused on the role of ten key regulators; ArsR, BaeR, CpxR, CusR, Fur, OxyR, SoxS, ZntR, ZraR and ... Microbiology journals http://www.medworm.com/rss/comments.php?id=5344651 Thu, 20 Oct 2011 04:00:00 +0100 5344651 http://www.medworm.com/index.php?rid=5344650&cid=s_37896_77_f&fid=37896&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22016572%26dopt%3DAbstract Authors: Matsutani M, Hirakawa H, Saichana N, Soemphol W, Yakushi T, Matsushita K Abstract Acetobacter pasteurianus is a Gram-negative strictly aerobic bacterium that is widely used for the industrial production of vinegar. Three Acetobacter pasteurianus strains, SKU1108, NBRC 3283, and IFO 3191, have the same 16S rRNA sequence (100% sequence identity), but show different thermotolerance. To clarify the relationships between phylogeny and thermotolerance of these strains, genome-wide analysis of these three strains was performed. Concatenated phylogenetic analysis of a dataset of 1864 orthologs has shown that the more thermotolerant strains, SKU1108 and NBRC 3283, are more closely related to each other than the more thermosensitive strain, IFO 3191. In addition, we defined a datase... Microbiology journals http://www.medworm.com/rss/comments.php?id=5344650 Thu, 20 Oct 2011 04:00:00 +0100 5344650 http://www.medworm.com/index.php?rid=5344649&cid=s_37896_77_f&fid=37896&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22016573%26dopt%3DAbstract In this study, respiratory growth with added manganese resulted in significant higher cell densities compared to the other growth conditions, while without manganese added, similar but lower cell densities were reached. Notably, cells derived from the respiratory cultures showed the highest hydrogen peroxide resistance in all conditions tested, although similar activity levels of heme-dependent catalase were detected in aerobic with heme grown cells. These results indicate that oxidative stress resistance of L. plantarum is affected by respiratory growth, growth phase, heme and manganese. Since heme and manganese levels can differ considerably in raw materials used in fermentations including milk, meat and vegetables, the insights obtained may provide tools to increase performance and robu... Microbiology journals http://www.medworm.com/rss/comments.php?id=5344649 Thu, 20 Oct 2011 04:00:00 +0100 5344649 http://www.medworm.com/index.php?rid=5344664&cid=s_37896_77_f&fid=37896&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21998160%26dopt%3DAbstract This study identified one such mechanism, the L-amino acid oxidase (Lao1) enzyme of Hebeloma cylindrosporum, by 2D-gel separation and mass spectrometry. We determined genomic DNA sequences of lao1 and part of its upstream gene, a putative pyruvate decarboxylase (pdc2), and cloned the cDNA of lao1. The two genes were also identified and annotated from the genome of Laccaria bicolor. The lao1 and pdc2 gene structures were conserved between the two fungi. The intergenic region of L. bicolor possessed putative duplications not detected from H. cylindrosporum. Lao1 sequences possessed dinucleotide-binding motifs typical for flavoproteins. Lao1 was less than 23% identical to Lao-sequences described previously. Recombinant Lao1 of H. cylindrosporum was expressed in E. coli, purified, and refolded... Microbiology journals http://www.medworm.com/rss/comments.php?id=5344664 Thu, 13 Oct 2011 04:00:00 +0100 5344664 http://www.medworm.com/index.php?rid=5344663&cid=s_37896_77_f&fid=37896&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21998161%26dopt%3DAbstract In this report, we identified and characterized the QseBC QS system in A. hydrophila SSU and found that, as was the case with enterohemorrhagic E. coli, the open reading frames for the qseB (the response regulator) and qseC (the sensor histidine kinase) genes overlapped by 4 bp at the ATGA motif. Our data provided evidence that deletion of the qseB gene from A. hydrophila resulted in attenuation of bacterial virulence in a septicemic mouse model of infection and diminished swimming and swarming motility, and the mutant bacteria formed denser biofilms when compared to those from the parental strain of A. hydrophila. The decrease in the virulence of the A. hydrophila qseB mutant correlated with reduced production of protease and the cytotoxic enterotoxin, which has associated hemolytic activ... Microbiology journals http://www.medworm.com/rss/comments.php?id=5344663 Thu, 13 Oct 2011 04:00:00 +0100 5344663 http://www.medworm.com/index.php?rid=5344662&cid=s_37896_77_f&fid=37896&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21998162%26dopt%3DAbstract In this study, plasminogen-to-plasmin conversion on killed and viable hypoencapsulated strains of C. neoformans required the addition of plasminogen activator (PA), but this conversion occurred in the absence of supplemented PA when viable strains were cultured with brain microvascular endothelial cells (BMEC). Plasmin-coated C. neoformans showed an enhanced invasive ability in Matrigel invasion assays that was significantly augmented in the presence of BMEC. The invasive effect of plasmin required viable pathogen and correlated with rapid declines in BMEC-barrier function. Plasmin-enhanced invasion was inhibited by aprotinin, carboxypeptidase B, the lysine analog εACA, and by capsule development. C. neoformans caused plasminogen-independent declines in BMEC barrier function that were ass... Microbiology journals http://www.medworm.com/rss/comments.php?id=5344662 Thu, 13 Oct 2011 04:00:00 +0100 5344662 http://www.medworm.com/index.php?rid=5344661&cid=s_37896_77_f&fid=37896&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21998163%26dopt%3DAbstract Authors: Peterson R, Nevalainen H Abstract AbstractThe hypersecreting mutant Trichoderma reesei RUT-C30 (ATCC 56765) is one of the most widely used strains of filamentous fungi for the production of cellulolytic enzymes, recombinant proteins, and for academic research. The strain was obtained after three rounds of random mutagenesis of the wild-type QM6a in a screening program focused on high cellulase production and catabolite derepression. Whereas RUT-C30 achieves outstanding levels of protein secretion and high cellulolytic activity in comparison to the wild-type QM6a, recombinant protein production has been less successful. Here we bring together and discuss the results from biochemical, microscopic, genomic, transcriptomic, glycomic and proteomic-based research published over ... Microbiology journals http://www.medworm.com/rss/comments.php?id=5344661 Thu, 13 Oct 2011 04:00:00 +0100 5344661 http://www.medworm.com/index.php?rid=5344660&cid=s_37896_77_f&fid=37896&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21998164%26dopt%3DAbstract Authors: Xue X, Li J, Wang W, Sztajer H, Wagner-Doebler I Abstract Transcriptional specificity in low G+C Gram positive bacteria is maintained by RpoE, the delta subunit of the RNA polymerase. Here, we studied the role of RpoE on the proteome level in the human dental pathogen Streptococcus mutans by comparing the rpoE mutant to the wild type under five conditions: (0) logarithmic growth, (1) early stationary phase, (2) acid stress, (3) oxidative stress, and (4) combined acid and oxidative stress. A total of 280 cellular protein spots were reproducibly detected, of which 97 differentially expressed protein spots were identified by MALDI-TOF MS. Lack of RpoE caused down-regulation of proteins for carbohydrate metabolism and energy production, including the phosphoglucomutase PGM, th... Microbiology journals http://www.medworm.com/rss/comments.php?id=5344660 Thu, 13 Oct 2011 04:00:00 +0100 5344660 http://www.medworm.com/index.php?rid=5344659&cid=s_37896_77_f&fid=37896&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21998165%26dopt%3DAbstract Authors: Mukherjee P, Horwitz B, Kenerley C Abstract Trichoderma spp. are a rich source of secondary metabolites. Recent publications of the genome sequences of three Trichoderma spp. have revealed a vast repertoire of genes putatively involved in biosynthesis of secondary metabolites, such as the non-ribosomal peptides, polyketides, terpenoids and pyrones. Interestingly, the genomes of the mycoparasitic species, T. virens and T. atroviride, are enriched in secondary metabolism-related genes compared to the biomass degrading T. reesei: 18 and 18 polyketide synthases compared to 11; 28 and 16 non-ribosomal peptide synthetases compared to 10, respectively. All three species produce a special class of non-ribosomally synthesized peptides, known as peptaibols, containing non-proteinoge... Microbiology journals http://www.medworm.com/rss/comments.php?id=5344659 Thu, 13 Oct 2011 04:00:00 +0100 5344659 http://www.medworm.com/index.php?rid=5344658&cid=s_37896_77_f&fid=37896&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21998166%26dopt%3DAbstract Authors: Hermosa R, Viterbo A, Chet I, Monte E Abstract Trichoderma (teleomorph Hypocrea) is a fungal genus found in many ecosystems. Trichoderma spp. can reduce the severity of plant diseases by inhibiting plant pathogens in the soil through their highly potent antagonistic and mycoparasitic activity. Moreover, as revealed by research in recent decades, some Trichoderma strains can interact directly with roots, increasing plant growth potential, resistance to disease, and tolerance to abiotic stresses. This mini-review summarizes the main findings concerning the Trichoderma-plant interaction, the molecular dialogue between both organisms, and the dramatic changes induced by the beneficial fungus in the plant. Efforts to ameliorate plant resistance and tolerance to a broad range of... Microbiology journals http://www.medworm.com/rss/comments.php?id=5344658 Thu, 13 Oct 2011 04:00:00 +0100 5344658 http://www.medworm.com/index.php?rid=5296638&cid=s_37896_77_f&fid=37896&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21980115%26dopt%3DAbstract Authors: de Bruin OM, Duplantis BN, Ludu JS, Hare RF, Nix EB, Schmerk CL, Robb CS, Boraston AB, Hueffer K, Nano FE Abstract The Francisella pathogenicity island (FPI) encodes proteins thought to compose a type VI secretion system (T6SS) that is required for the intracellular growth of F. novicida. In this work we used deletion mutagenesis and genetic complementation to determine that the intracellular growth of F. novicida was dependent on 14 of the 18 genes in the FPI. The products of the iglABCD operon were localized by the biochemical fractionation of F. novicida, and F. tularensis LVS. Sucrose gradient separation of water insoluble material showed that the FPI-encoded proteins IglA, IglB, and IglC were found in multiple fractions, especially in a fraction that did not correspon... Microbiology journals http://www.medworm.com/rss/comments.php?id=5296638 Thu, 06 Oct 2011 04:00:00 +0100 5296638 http://www.medworm.com/index.php?rid=5296637&cid=s_37896_77_f&fid=37896&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21980116%26dopt%3DAbstract Authors: Thomas GH, Boyd EF Abstract No abtract this is a comment. PMID: 21980116 [PubMed - as supplied by publisher] (Source: Microbiology) Microbiology journals http://www.medworm.com/rss/comments.php?id=5296637 Thu, 06 Oct 2011 04:00:00 +0100 5296637 http://www.medworm.com/index.php?rid=5296636&cid=s_37896_77_f&fid=37896&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21980117%26dopt%3DAbstract Authors: Matarese F, Sarrocco S, Gruber S, Seidl-Seiboth V, Vannacci G Abstract Fusarium Head Blight (FHB) is a re-emerging wheat disease that causes extensive damage through direct losses in yield and quality due to the presence of Fusarium damaged kernels and their associated mycotoxins such as the trichothecene deoxynivalenol (DON). Biological control, including the treatment of crop residues with antagonists, in order to reduce pathogen inoculum of FHB, holds considerable promise. Ten Trichoderma isolates, previously selected for their ability to grow in the presence of DON, were preliminary investigated as potential antagonists against Fusarium culmorum and F. graminearum mycotoxigenic strains in plate confrontation assays. The three Trichoderma isolates showing antibiosis and... Microbiology journals http://www.medworm.com/rss/comments.php?id=5296636 Thu, 06 Oct 2011 04:00:00 +0100 5296636 http://www.medworm.com/index.php?rid=5296635&cid=s_37896_77_f&fid=37896&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21980118%26dopt%3DAbstract Authors: Kjos M, Borrero J, Opsata M, Birri DJ, Holo H, Cintas LM, Snipen L, Hernández PE, Nes IF, Diep DB Abstract Due to their very potent antimicrobial activity against diverse food-spoiling bacteria and pathogens and their favourable biochemical properties, peptide bacteriocins from Gram-positive bacteria have long been considered promising for applications in food preservation or medical treatment. To take advantage of bacteriocins in different applications, it is crucial to have detailed knowledge on the molecular mechanisms by which these peptides recognize and kill target cells, how producer cells protect themselves from their own bacteriocin (self-immunity) and how target cells may develop resistance. In this review we discuss some important recent progress in these areas... Microbiology journals http://www.medworm.com/rss/comments.php?id=5296635 Thu, 06 Oct 2011 04:00:00 +0100 5296635 http://www.medworm.com/index.php?rid=5296657&cid=s_37896_77_f&fid=37896&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21719543%26dopt%3DAbstract Authors: Jahn CE, Selimi DA, Barak JD, Charkowski AO Abstract Dickeya dadantii is a plant-pathogenic bacterium that produces cellulose-containing biofilms, called pellicles, at the air-liquid interface of liquid cultures. D. dadantii pellicle formation appears to be an emergent property dependent upon at least three gene clusters, including cellulose synthesis, type III secretion system (T3SS) and flagellar genes. The D. dadantii cellulose synthesis operon is homologous to that of Gluconacetobacter xylinus, which is used for industrial cellulose production, and the cellulose nanofibres produced by D. dadantii were similar in diameter and branching pattern to those produced by G. xylinus. Salmonella enterica, an enterobacterium closely related to D. dadantii, encodes a second type o... Microbiology journals http://www.medworm.com/rss/comments.php?id=5296657 Sat, 01 Oct 2011 04:00:00 +0100 5296657 http://www.medworm.com/index.php?rid=5296656&cid=s_37896_77_f&fid=37896&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21737495%26dopt%3DAbstract Authors: Lee HJ, Kim JM, Lee SH, Park M, Lee K, Madsen EL, Jeon CO Abstract Polaromonas naphthalenivorans strain CJ2 metabolizes naphthalene via the gentisate pathway and has recently been shown to carry a third copy of gentisate 1,2-dioxygenase (GDO), encoded by nagI3, within a previously uncharacterized naphthalene catabolic gene cluster. The role of this cluster (especially nagI3) in naphthalene metabolism of strain CJ2 was investigated by documenting patterns in regulation, transcription and enzyme activity. Transcriptional analysis of wild-type cells showed the third cluster to be polycistronic and that nagI3 was expressed at a relatively high level. Individual knockout mutants of all three nagI genes were constructed and their influence on both GDO activity and cell growth wa... Microbiology journals http://www.medworm.com/rss/comments.php?id=5296656 Sat, 01 Oct 2011 04:00:00 +0100 5296656 http://www.medworm.com/index.php?rid=5296655&cid=s_37896_77_f&fid=37896&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21737497%26dopt%3DAbstract In this study we used the bacterial adenylate cyclase-based two-hybrid assay to investigate interactions between known PHB granule-associated proteins (PGAPs) and to screen for new PGAPs. The utility of the system was tested by the in vivo verification of previously postulated interactions of the PHB synthase subunits of R. eutropha (PhaC1 homo-oligomerization) and of Bacillus megaterium (PhaC(Bmeg)-PhaR(Bmeg) hetero-oligomerization). Nine proteins (PhaA, PhaB1, PhaC1, PhaP1-PhaP4, PhaZ1 and PhaR), with established functions in PHB metabolism of R. eutropha, were tested for interaction in all combinations. While no significant interaction was detected between the PHB synthase PhaC1 and any of the other eight tested Pha proteins, strong interactions were found between all phasin proteins, i... Microbiology journals http://www.medworm.com/rss/comments.php?id=5296655 Sat, 01 Oct 2011 04:00:00 +0100 5296655 http://www.medworm.com/index.php?rid=5296654&cid=s_37896_77_f&fid=37896&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21737498%26dopt%3DAbstract Authors: Desai SS, Rajpurohit YS, Misra HS, Deobagkar DN Abstract Deinococcus radiodurans shows extraordinary tolerance to DNA damage, and exhibits differential gene expression and protein recycling. A putative response regulator, the DRB0091 (RadR) ORF, was identified from a pool of DNA-binding proteins induced in response to gamma radiation in this bacterium. radR is located upstream of drB0090, which encodes a putative sensor histidine kinase (RadS) on the megaplasmid. Deletion of these genes both individually and together resulted in hypersensitivity to DNA-damaging agents and a delayed or altered double-strand break repair. A ΔradRradS double mutant and a ΔradR single mutant showed nearly identical responses to gamma radiation and UVC. Wild-type RadR and RadS complemented th... Microbiology journals http://www.medworm.com/rss/comments.php?id=5296654 Sat, 01 Oct 2011 04:00:00 +0100 5296654 http://www.medworm.com/index.php?rid=5296653&cid=s_37896_77_f&fid=37896&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21737499%26dopt%3DAbstract Authors: Molero R, Wilhelms M, Infanzón B, Tomás JM, Merino S Abstract By the analysis of the Aeromonas hydrophila ATCC7966(T) genome we identified A. hydrophila AH-3 MotY. A. hydrophila MotY, like MotX, is essential for the polar flagellum function energized by an electrochemical potential of Na(+) as coupling ion, but is not involved in lateral flagella function energized by the proton motive force. Thus, the A. hydrophila polar flagellum stator is a complex integrated by two essential proteins, MotX and MotY, which interact with one of two redundant pairs of proteins, PomAB and PomA(2)B(2). In an A. hydrophila motX mutant, polar flagellum motility is restored by motX complementation, but the ability of the A. hydrophila motY mutant to swim is not restored by introduction of th... Microbiology journals http://www.medworm.com/rss/comments.php?id=5296653 Sat, 01 Oct 2011 04:00:00 +0100 5296653 http://www.medworm.com/index.php?rid=5296652&cid=s_37896_77_f&fid=37896&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21757488%26dopt%3DAbstract Authors: Dorin-Semblat D, Schmitt S, Semblat JP, Sicard A, Reininger L, Goldring D, Patterson S, Quashie N, Chakrabarti D, Meijer L, Doerig C Abstract The Plasmodium falciparum kinome includes a family of four protein kinases (Pfnek-1 to -4) related to the NIMA (never-in-mitosis) family, members of which play important roles in mitosis and meiosis in eukaryotic cells. Only one of these, Pfnek-1, which we previously characterized at the biochemical level, is expressed in asexual parasites. The other three (Pfnek-2, -3 and -4) are expressed predominantly in gametocytes, and a role for nek-2 and nek-4 in meiosis has been documented. Here we show by reverse genetics that Pfnek-1 is required for completion of the asexual cycle in red blood cells and that its expression in gametocytes in... Microbiology journals http://www.medworm.com/rss/comments.php?id=5296652 Sat, 01 Oct 2011 04:00:00 +0100 5296652 http://www.medworm.com/index.php?rid=5296651&cid=s_37896_77_f&fid=37896&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21778204%26dopt%3DAbstract Authors: Relich RF, Balish MF Abstract The attachment organelles of bacterial species belonging to the Mycoplasma pneumoniae phylogenetic cluster are required for host cytadherence, gliding motility and virulence. Despite being closely related, these bacteria possess distinct cellular morphologies and gliding characteristics. The molecular mechanisms for most attachment organelle phenotypes, including shape and ability to power motility, are obscure. The attachment organelle-associated P30 protein of M. pneumoniae is implicated in both adherence and motility, with mutations negatively impacting cell morphology, adherence, gliding and virulence. To test whether the P30 alleles of different mycoplasma species confer species-specific attachment organelle properties, we created an M. p... Microbiology journals http://www.medworm.com/rss/comments.php?id=5296651 Sat, 01 Oct 2011 04:00:00 +0100 5296651 http://www.medworm.com/index.php?rid=5296650&cid=s_37896_77_f&fid=37896&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21778207%26dopt%3DAbstract In this study, we show that the transcriptional regulator CelR, which has previously been found to be important for pneumococcal virulence, activates the expression of the cellobiose-utilization gene cluster (cel locus) of S. pneumoniae. Expression directed by the two promoters present in the cel locus was increased in the presence of cellobiose as sole carbon source in the medium, while expression decreased in the presence of glucose in the medium. Furthermore, we have predicted a 22 bp putative CelR regulatory site (5'-YTTTCCWTAWCAWTWAGGAAAA-3') in the promoters of celA and celB, and in silico analysis showed that it is highly conserved in other pathogenic streptococci as well. Promoter truncations of celA and celB, where the half or full CelR regulatory site was deleted, confirmed that ... Microbiology journals http://www.medworm.com/rss/comments.php?id=5296650 Sat, 01 Oct 2011 04:00:00 +0100 5296650 http://www.medworm.com/index.php?rid=5296649&cid=s_37896_77_f&fid=37896&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21778208%26dopt%3DAbstract This study suggests that TCP may be one factor that V. cholerae utilizes for adaptation and survival during the transition between the host and the aquatic environment. PMID: 21778208 [PubMed - in process] (Source: Microbiology) Microbiology journals http://www.medworm.com/rss/comments.php?id=5296649 Sat, 01 Oct 2011 04:00:00 +0100 5296649 http://www.medworm.com/index.php?rid=5296648&cid=s_37896_77_f&fid=37896&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21778210%26dopt%3DAbstract Authors: Jewett MW, Jain S, Linowski AK, Sarkar A, Rosa PA Abstract The conversion of nicotinamide to nicotinic acid by nicotinamidase enzymes is a critical step in maintaining NAD(+) homeostasis and contributes to numerous important biological processes in diverse organisms. In Borrelia burgdorferi, the nicotinamidase enzyme, PncA, is required for spirochaete survival throughout the infectious cycle. Mammals lack nicotinamidases and therefore PncA may serve as a therapeutic target for Lyme disease. Contrary to the in vivo importance of PncA, the current annotation for the pncA ORF suggests that the encoded protein may be inactive due to the absence of an N-terminal aspartic acid residue that is a conserved member of the catalytic triad of characterized PncA proteins. Herein, we ha... Microbiology journals http://www.medworm.com/rss/comments.php?id=5296648 Sat, 01 Oct 2011 04:00:00 +0100 5296648 http://www.medworm.com/index.php?rid=5296647&cid=s_37896_77_f&fid=37896&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21798981%26dopt%3DAbstract Authors: Li X, McInerney MJ, Stahl DA, Krumholz LR Abstract Syntrophic growth involves the oxidation of organic compounds and subsequent transfer of electrons to an H(2)- or formate-consuming micro-organism. In order to identify genes involved specifically in syntrophic growth, a mutant library of Desulfovibrio alaskensis G20 was screened for loss of the ability to grow syntrophically with Methanospirillum hungatei JF-1. A collection of 20 mutants with an impaired ability to grow syntrophically was obtained. All 20 mutants grew in pure culture on lactate under sulfidogenic conditions at a rate and to a maximum OD(600) similar to those of the parental strain. The largest number of mutations that affected syntrophic growth with lactate was in genes encoding proteins involved in H(2) ... Microbiology journals http://www.medworm.com/rss/comments.php?id=5296647 Sat, 01 Oct 2011 04:00:00 +0100 5296647 http://www.medworm.com/index.php?rid=5296646&cid=s_37896_77_f&fid=37896&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21798983%26dopt%3DAbstract Authors: Kolmsee T, Delic D, Agyenim T, Calles C, Wagner R Abstract Transcription of rRNAs in Escherichia coli is directed from seven redundant rRNA operons, which are mainly regulated by their P1 promoters. Here we demonstrate by in vivo measurements that the amounts of individual rRNAs transcribed from the different operons under normal growth vary noticeably although the structures of all the P1 promoters are very similar. Moreover, we show that starvation for amino acids does not affect the seven P1 promoters in the same way. Notably, reduction of transcription from rrnD P1 was significantly lower compared to the other P1 promoters. The presence of DksA was shown to be crucial for the ppGpp-dependent downregulation of all P1 promoters. Because rrnD P1 is the only rrn promoter s... Microbiology journals http://www.medworm.com/rss/comments.php?id=5296646 Sat, 01 Oct 2011 04:00:00 +0100 5296646 http://www.medworm.com/index.php?rid=5296645&cid=s_37896_77_f&fid=37896&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21798984%26dopt%3DAbstract In this study, we demonstrate that EHEC blocks tumour necrosis factor-alpha (TNFα)-induced NF-κB signalling in infected epithelial cells. HEK293T and INT407 epithelial cells were challenged with EHEC prior to stimulation with TNFα. Using complementary techniques, stimulation with TNFα caused activation of NF-κB, as determined by luciferase reporter assay (increase in gene expression), Western blotting (phosphorylation of IκBα), immunofluorescence (p65 nuclear translocation) and immunoassay (CXCL-8 secretion), and each was blocked by EHEC O157 : H7 infection. In contrast, subversion of host cell signalling was not observed following exposure to either enteropathogenic E. coli, strain E2348/69 (O127 : H6) or the laboratory E. coli strain HB101. Heat-killed EHEC had no effect o... Microbiology journals http://www.medworm.com/rss/comments.php?id=5296645 Sat, 01 Oct 2011 04:00:00 +0100 5296645 http://www.medworm.com/index.php?rid=5296644&cid=s_37896_77_f&fid=37896&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21816880%26dopt%3DAbstract In this study we report RNA-seq analyses of the transcriptomes of C. jejuni (NCTC11168) and its rpoN mutant. This has allowed the identification of hitherto unknown transcriptional units, and further defines the regulon that is dependent on rpoN for expression. The analysis of the NCTC11168 transcriptome was supplemented by additional proteomic analysis using liquid chromatography-MS. The transcriptomic and proteomic datasets represent an important resource for the Campylobacter research community. PMID: 21816880 [PubMed - in process] (Source: Microbiology) Microbiology journals http://www.medworm.com/rss/comments.php?id=5296644 Sat, 01 Oct 2011 04:00:00 +0100 5296644 http://www.medworm.com/index.php?rid=5296643&cid=s_37896_77_f&fid=37896&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21964731%26dopt%3DAbstract In this study, we re-examined the role of rmpA/A2 in PLA pathogenesis to clarify the relationship of rmpA/A2 and capsular serotype to virulence. Using isogenic gene deletion strains and complementation strains of NTUH-K2044, we demonstrated that only p-rmpA enhanced expression of capsular polysaccharide synthesis (cps) genes and capsule production. Nevertheless, the lethal dose and in vivo competition index indicated that p-rmpA does not promote virulence in mice. The prevalence of these three rmpA/A2 and capsular types in 206 strains were investigated. We revealed a correlation of rmpA/A2 with six PLA-related capsular types (K1, K2, K5, K54, K57 and KN1). Among three rmpA/A2, p-rmpA was the most prevalent. Due to the strong correlation with PLA-related capsular types, p-rmpA could serve a... Microbiology journals http://www.medworm.com/rss/comments.php?id=5296643 Thu, 29 Sep 2011 04:00:00 +0100 5296643 http://www.medworm.com/index.php?rid=5296642&cid=s_37896_77_f&fid=37896&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21964732%26dopt%3DAbstract Authors: Sadykov M, Hartmann T, Mattes T, Hiatt M, Jann N, Zhu Y, Ledala N, Landmann R, Herrmann M, Rohde H, Bischoff M, Somerville G Abstract Staphylococcus epidermidis is an opportunistic bacterium whose infections often involve the formation of a biofilm on implanted biomaterials. In S. epidermidis, the exopolysaccharide facilitating bacterial adherence in a biofilm is polysaccharide intercellular adhesin (PIA), whose synthesis requires the enzymes coded within the intercellular adhesin operon (icaADBC). In vitro, the formation of S. epidermidis biofilms is enhanced by conditions that repress tricarboxylic acid (TCA) cycle activity, such as growth in a medium containing glucose. In many gram-positive bacteria, repression of TCA cycle genes in response to glucose is accomplished ... Microbiology journals http://www.medworm.com/rss/comments.php?id=5296642 Thu, 29 Sep 2011 04:00:00 +0100 5296642 http://www.medworm.com/index.php?rid=5296641&cid=s_37896_77_f&fid=37896&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21964733%26dopt%3DAbstract Authors: Huang SC, Lin TH, Shaw GC Abstract The soil bacterium Bacillus subtilis can utilize exogenous proline as a sole nitrogen or carbon source. The proline-inducible putBCP (formerly ycgMNO) operon encodes proteins responsible for proline uptake and two-step oxidation of proline to glutamate. We now report that a gene (formerly ycgP, now designated prcR) located downstream of the putBCP operon is essential for B. subtilis cells to utilize proline as a sole nitrogen or carbon source. Disruption of the prcR gene also abolished proline induction of putB transcription. prcR expression is not subject to autoregulation and proline induction. The PrcR protein shows no significant amino acid sequence similarity to the known transcriptional activators for proline utilization genes of ot... Microbiology journals http://www.medworm.com/rss/comments.php?id=5296641 Thu, 29 Sep 2011 04:00:00 +0100 5296641 http://www.medworm.com/index.php?rid=5296640&cid=s_37896_77_f&fid=37896&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21964734%26dopt%3DAbstract Authors: Carreras-Villaseñor N, Sánchez-Arreguín A, Herrera-Estrella AH Abstract Species belonging to the genus Trichoderma are free-living fungi common in soil and root ecosystems, and are used broadly in industry and agricultural biotechnology. Some species of the genus are widely used biocontrol agents, and their success is in part due to mycoparasitism, a lifestyle where one fungus is parasitic on another fungus. In addition Trichoderma species have been found to elicit plant defense responses and to stimulate plant growth. In order to survive and spread, Trichoderma switches from vegetative to reproductive development, and has evolved with several sophisticated molecular mechanisms to this end. Asexual development (conidiation) is induced by light and mechanical injury, alt... Microbiology journals http://www.medworm.com/rss/comments.php?id=5296640 Thu, 29 Sep 2011 04:00:00 +0100 5296640 http://www.medworm.com/index.php?rid=5296639&cid=s_37896_77_f&fid=37896&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21964735%26dopt%3DAbstract Authors: Postmus J, Tuzun I, Bekker M, Müller WH, Teixeira de Mattos JM, Brul S, Smits GJ Abstract To adapt to changes in the environment, cells have to dynamically alter their phenotype in response to for instance temperature and oxygen availability. Interestingly, mitochondrial function in Saccharomyces cerevisiae is inherently temperature sensitive; above 37ºC yeast cells can not grow on respiratory carbon sources. To investigate this phenomenon, we studied the effect of cultivation temperature on the efficiency (production of ATP per oxygen consumed, or P/O) of the yeast respiratory chain in glucose-limited chemostats. We determined that even although the specific oxygen consumption rate did not change with temperature, oxygen consumption no longer contributed to mitochondria... Microbiology journals http://www.medworm.com/rss/comments.php?id=5296639 Thu, 29 Sep 2011 04:00:00 +0100 5296639 http://www.medworm.com/index.php?rid=5278983&cid=s_37896_77_f&fid=37896&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21948044%26dopt%3DAbstract In this study, three additional Qrr sRNAs were identified. All four sRNAs were positively regulated by Sigma 54 and the sigma-54-dependent response regulator VanO and showed a redundant activity. The Qrr sRNAs, together with the RNA chaperone Hfq, destabilized vanT mRNA and modulated expression of VanT-regulated genes. Unexpectedly, expression of all four qrr genes peaked at high cell density and exogenously added N-acylhomoserine lactone molecules induced expression of the qrr genes at low cell density. The phosphotransferase, VanU, which phosphorylates and activates VanO, repressed expression of the Qrr sRNAs and stabilized vanT mRNA. A model is presented proposing that VanU acts as a branch point aiding cross regulation between two independent phosphorelay systems that activate or repre... Microbiology journals http://www.medworm.com/rss/comments.php?id=5278983 Wed, 21 Sep 2011 04:00:00 +0100 5278983 http://www.medworm.com/index.php?rid=5278982&cid=s_37896_77_f&fid=37896&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21948045%26dopt%3DAbstract Authors: Shintani M, Matsumoto T, Yoshikawa H, Yamane H, Ohkuma M, Hideaki N Abstract The carbazole-degradative plasmid pCAR1 carries the class II transposon Tn4676 that contains the car and ant genes, which are essential for conversion of carbazole into anthranilate, and anthranilate into catechol, respectively. In our previous study, DNA rearrangements in pCAR1 were frequently detected in the host Pseudomonas fluorescens Pf0-1 in the presence of carbazole, resulting in the improvement of host survivability. Several Pf0-1 mutants harbouring pCAR1 were isolated, and deletion of DNA in the plasmid ant gene was found. Here, we compared genome sequences of the parent strain Pf0-1L(pCAR1::rfp) and one of its mutants, 5EP83, to assess whether other DNA rearrangements occurred in either ... Microbiology journals http://www.medworm.com/rss/comments.php?id=5278982 Wed, 21 Sep 2011 04:00:00 +0100 5278982 http://www.medworm.com/index.php?rid=5278981&cid=s_37896_77_f&fid=37896&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21948046%26dopt%3DAbstract This study is the first to show natural transformation by gene cassettes, and integron-mediated capture of catabolic gene cassettes. PMID: 21948046 [PubMed - as supplied by publisher] (Source: Microbiology) Microbiology journals http://www.medworm.com/rss/comments.php?id=5278981 Wed, 21 Sep 2011 04:00:00 +0100 5278981 http://www.medworm.com/index.php?rid=5278980&cid=s_37896_77_f&fid=37896&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21948047%26dopt%3DAbstract Authors: Samolski I, Rincón AM, Pinzón LM, Viterbo A, Monte E Abstract Trichoderma harzianum qid74 gene encodes a cysteine-rich cell wall protein that has an important role in adherence to hydrophobic surfaces and cellular protection, which was up-regulated in Trichoderma high density oligonucleotide (HDO) microarrays in interaction with tomato roots. Using a collection of qid74 over-expressing and disrupted mutants the role of this gene in cucumber and tomato root architecture was analysed in hydroponic and soil systems under greenhouse conditions. No significant differences were found in the pattern of root colonization and the length of primary roots of cucumber or tomato plants inoculated by T. harzianum CECT 2413 wild-type (wt) strain or any of the qid74 transformants. Howev... Microbiology journals http://www.medworm.com/rss/comments.php?id=5278980 Wed, 21 Sep 2011 04:00:00 +0100 5278980 http://www.medworm.com/index.php?rid=5278979&cid=s_37896_77_f&fid=37896&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21948048%26dopt%3DAbstract Authors: Pérez-Mendoza D, Coulthurst SJ, Sanjuán J, Salmond GP Abstract The phytopathogenic bacterium Pectobacterium atrosepticum SCRI1043 (Pba) does not exhibit appreciable biofilm formation under standard laboratory conditions. Here we show that a biofilm forming phenotype in this strain could be activated from a cryptic state by increasing c-di-GMP intracellular levels, through overexpression of a constitutively active diguanylate cyclase (PleD*) from Caulobacter crescentus. Randomly obtained Pba transposon mutants defective in the pga operon, involved in synthesis and translocation of poly-β-1,6-N-acetyl-D-glucosamine (PGA), were all impaired in this biofilm formation. The presence of the PGA-degrading enzyme Dispersin B in the growth media prevented biofilm formation by Pba... Microbiology journals http://www.medworm.com/rss/comments.php?id=5278979 Wed, 21 Sep 2011 04:00:00 +0100 5278979 http://www.medworm.com/index.php?rid=5278978&cid=s_37896_77_f&fid=37896&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21948049%26dopt%3DAbstract Authors: Vijay Kumar N, Rangarajan PN Abstract We have identified a methanol- and biotin starvation-inducible zinc finger protein named ROP (repressor of phosphoenolpyruvate carboxykinase [PEPCK]) in the methylotrophic yeast, Pichia pastoris. When P. pastoris GS115 strain (WT) is cultured in biotin-deficient, glucose ammonium (Bio(-)) medium, growth is suppressed due to the inhibition of anaplerotic synthesis of oxaloacetate (OAA), catalyzed by the biotin-dependent enzyme pyruvate carboxylase (PC). Deletion of ROP results in a strain (ΔROP) that can grow under biotin-deficient conditions due to derepression of a biotin- and PC-independent pathway of anaplerotic synthesis of oxaloacetate. Northern analysis as well as microarray expression profiling of RNA isolated from WT and ΔROP... Microbiology journals http://www.medworm.com/rss/comments.php?id=5278978 Wed, 21 Sep 2011 04:00:00 +0100 5278978 http://www.medworm.com/index.php?rid=5278977&cid=s_37896_77_f&fid=37896&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21948050%26dopt%3DAbstract This study demonstrates that MLSA of housekeeping genes is a valuable alternative technique for the identification and classification of species of the genus Bacteroides. PMID: 21948050 [PubMed - as supplied by publisher] (Source: Microbiology) Microbiology journals http://www.medworm.com/rss/comments.php?id=5278977 Wed, 21 Sep 2011 04:00:00 +0100 5278977 http://www.medworm.com/index.php?rid=5229711&cid=s_37896_77_f&fid=37896&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21921101%26dopt%3DAbstract Authors: Helle L, Kull M, Mayer S, Marincola G, Zelder ME, Goerke C, Wolz C, Bertram R Abstract A set of vectors for improved tetracycline dependent gene regulation in Staphylococcus aureus is presented. Plasmid pRAB11 was generated from pRMC2 by adding a second tet operator within the TetR regulated promoter Pxyl/tet. Pronounced repression was observed in the absence of anhydrotetracycline (ATc) combined with high induction in the presence of the drug, as demonstrated for pRAB11 bearing staphylococcal nuclease nuc1, lacZ, or gfp. Also in plasmid pCG261, the pRAB11 tetR-Pxyl/tet regulatory architecture permitted tight repression and a stepwise increase in transcript amounts of the target gene rny (putative RNase) correlated to rising ATc concentrations. Additionally, pRAB11 derived... Microbiology journals http://www.medworm.com/rss/comments.php?id=5229711 Thu, 15 Sep 2011 04:00:00 +0100 5229711 http://www.medworm.com/index.php?rid=5229710&cid=s_37896_77_f&fid=37896&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21921102%26dopt%3DAbstract Authors: Zhou Y, Behrendt J, Sutherland A, Griffiths G Abstract The naturally occurring reactive electrophilic species (RES), 12-oxo-phytodienoic acid (12-oxo-PDA) is a potent antifungal agent, whereas the plant growth regulator, jasmonic acid (JA), which is synthesised from 12-oxo-PDA, is ineffective. In order to address what structural features of the molecule endow it with antifungal activity, we have synthesised a series of molecular mimics of 12-oxo-PDA varying in the length of the alkyl chain at its C4 ring position. The octyl analogue (4-octyl-cyclopentenone) was the most effective at suppressing spore germination and subsequent mycelial growth of a range of fungal pathogens and was particularly effective against Cladosporum herbarum and Botrytis cinerea with minimum fungici... Microbiology journals http://www.medworm.com/rss/comments.php?id=5229710 Thu, 15 Sep 2011 04:00:00 +0100 5229710 http://www.medworm.com/index.php?rid=5229709&cid=s_37896_77_f&fid=37896&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21921103%26dopt%3DAbstract Authors: Sevilla E, Martín-Luna B, González A, Gonzalo-Asensio JA, Peleato ML, Fillat MF Abstract The interplay between Fur (ferric uptake regulator) proteins and small, non-coding RNAs has been described as a key regulatory loop in several bacteria. In the filamentous cyanobacterium Anabaena sp. PCC 7120 a large dicistronic transcript encoding the putative membrane protein Alr1690 and an α-furA RNA is involved in the modulation of the global regulator FurA. In this work we report the existence of three new antisense RNAs in cyanobacteria and show that a cis α-furA RNA is conserved in very different genomic contexts, namely in the unicellular cyanobacteria Microcystis aeruginosa PCC 7806 and Synechocystis sp. PCC 6803. Syα-fur RNA covers only part of the coding sequence of the... Microbiology journals http://www.medworm.com/rss/comments.php?id=5229709 Thu, 15 Sep 2011 04:00:00 +0100 5229709 http://www.medworm.com/index.php?rid=5218779&cid=s_37896_77_f&fid=37896&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21903750%26dopt%3DAbstract Authors: Reffuveille F, Leneveu C, Chevalier S, Auffray Y, Rincé A Abstract Enterococcus faecalis is an ubiquitous bacterium that is capable of surviving in a broad range of natural environments, including the human host, either as a natural commensal or as an opportunistic pathogen involved in severe hospital acquired infections. How such opportunistic pathogens cause fatal infections is largely unknown but they should be equipped with sophisticated systems to perceive external signals and interact with eukaryote cells. Accordingly, being partially exposed at the cell exterior, some surface associated proteins are involved in several steps of the infection process. Among them are lipoproteins, representing about 25% of the surface associated proteins, which could play a major rol... Microbiology journals http://www.medworm.com/rss/comments.php?id=5218779 Thu, 08 Sep 2011 04:00:00 +0100 5218779 http://www.medworm.com/index.php?rid=5218778&cid=s_37896_77_f&fid=37896&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21903751%26dopt%3DAbstract Authors: Peuser V, Glaeser J, Klug G Abstract Metal homeostasis is important in all living cells in order to provide sufficient amounts of metal ions for biological processes but to prevent toxic effects by excess amounts. Here we show that the gene product of RSP_2889 of the facultatively photosynthetic bacterium Rhodobacter sphaeroides is homologous to CueR, a regulator of copper metabolism in Escherichia coli and other bacteria. CueR binds to the promoter regions of genes for a copper translocating ATPase and for a copper chaperone and is responsible for their high expression when cells are exposed to elevated levels of copper ions. While deletion of RSP_2889 has no significant effect on copper resistance, expression from a low copy number plasmid mediates increased sensitivity ... Microbiology journals http://www.medworm.com/rss/comments.php?id=5218778 Thu, 08 Sep 2011 04:00:00 +0100 5218778 http://www.medworm.com/index.php?rid=5218777&cid=s_37896_77_f&fid=37896&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21903752%26dopt%3DAbstract In this study, we used lipidomics to compare the lipid profile of C. albicans biofilms and planktonic cells, at early and mature developmental phases. Our results showed that significant differences exist in lipid composition at both developmental phases. Biofilms contained higher levels of phospholipid and sphingolipids than planktonic cells (nmol/g biomass, P< .05 for all comparisons). At early phase, levels of lipid in most classes were significantly higher in biofilms compared to planktonic cells (P≤.05). The ratio of phosphatidylcholine (PC) to phosphatidylethanolamine (PE) was lower in biofilms compared to planktonic cells at early (1.17 vs. 2.52, P ≤ .001) and late developmental times (2.34 vs. 3.81, P ≤ .001). The unsaturation index of phospholipids decreased with time, wi... Microbiology journals http://www.medworm.com/rss/comments.php?id=5218777 Thu, 08 Sep 2011 04:00:00 +0100 5218777 http://www.medworm.com/index.php?rid=5218776&cid=s_37896_77_f&fid=37896&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21903753%26dopt%3DAbstract Authors: Seibold GM, Breitinger KJ, Kempkes R, Both L, Krämer M, Dempf S, Eikmanns BJ Abstract Corynebacterium glutamicum transiently accumulates glycogen as carbon capacitor during the early exponential growth phase in media containing carbohydrates. In some bacteria glycogen is synthesized by the consecutive action of ADP-glucose pyrophosphorylase (GlgC), glycogen synthase (GlgA) and glycogen branching enzyme (GlgB). GlgC and GlgA of C. glutamicum have been shown to be necessary for the glycogen accumulation in this organism. However, although cg1381 has been annotated as putative C. glutamicum glgB gene, cg1381 and its gene product have not been characterized and their role for the transient glycogen accumulation have not been investigated yet. We here show, that the cg1381 gen... Microbiology journals http://www.medworm.com/rss/comments.php?id=5218776 Thu, 08 Sep 2011 04:00:00 +0100 5218776 http://www.medworm.com/index.php?rid=5218775&cid=s_37896_77_f&fid=37896&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21903754%26dopt%3DAbstract Authors: Müller M, Marx P, Hakenbeck R, Brückner R Abstract The two-component regulatory system CiaRH of Streptococcus pneumoniae affects β-lactam susceptibility, autolysis, bacteriocin production, competence development, host colonization, and virulence. The system was discovered in a screen for S. pneumoniae R6 mutants resistant to the β-lactam antibiotic cefotaxime. A mutation in the histidine kinase gene ciaH led to this phenotype by enhancing CiaR-mediated gene expression. Additional mutations in ciaH have been described in other spontaneous β-lactam resistant mutants of S. pneumoniae R6, but their influence on CiaR-mediated gene regulation has not been determined. Likewise, altered ciaH alleles are present in clinical S. pneumoniae isolates, none of which had been charac... Microbiology journals http://www.medworm.com/rss/comments.php?id=5218775 Thu, 08 Sep 2011 04:00:00 +0100 5218775 http://www.medworm.com/index.php?rid=5218774&cid=s_37896_77_f&fid=37896&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21903755%26dopt%3DAbstract Authors: Kropec A, Sava IG, Vonend C, Sakinc T, Grohmann E, Huebner J Abstract Infections caused by multiresistant Gram-positive bacteria represent a major health burden in the community as well as in hospitalized patients. Enterococci, especially Enterococcus faecium, are well-known pathogens of hospitalized patients and are frequently linked with resistance against multiple antibiotics, which compromises effective therapy. Immune rabbit serum raised against heat-killed E. faecium E155, a HiRECC clone, was used in an opsonophagocytic assay (OPA), an inhibition assay, and a mouse bacteremia model to identify targets of opsonic and protective antibodies. Serum against whole heat-killed bacteria was opsonic and recognized a protein of about 72 kD that was abundantly secreted. This pr... Microbiology journals http://www.medworm.com/rss/comments.php?id=5218774 Thu, 08 Sep 2011 04:00:00 +0100 5218774 http://www.medworm.com/index.php?rid=5218773&cid=s_37896_77_f&fid=37896&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21903756%26dopt%3DAbstract Authors: Kitagawa R, Takaya A, Yamamoto T Abstract In enterobacteria, such as Escherichia coli and Salmonella, flagellar biogenesis is strictly dependent upon the master regulator flhDC. Here, we demonstrate that in enterohaemorrhagic E. coli (EHEC), the flagellar regulon is controlled by ClpXP, a member of the ATP-dependent protease family, through dual pathways: (i) post-translational control of the FlhD/FlhC master regulator, and (ii) transcriptional control of the flhDC operon. Both FlhD and FlhC proteins accumulated markedly following ClpXP depletion, and their half-lives were significantly longer in the mutant cells, suggesting that ClpXP is responsible for degrading FlhD and FlhC proteins, leading to down-regulation of flagellar expression. ClpXP was involved in regulating t... Microbiology journals http://www.medworm.com/rss/comments.php?id=5218773 Thu, 08 Sep 2011 04:00:00 +0100 5218773 http://www.medworm.com/index.php?rid=5218772&cid=s_37896_77_f&fid=37896&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21903757%26dopt%3DAbstract Authors: Sygmund C, Klausberger M, Felice AK, Ludwig R Abstract The plant pathogenic fungus Glomerella cingulata (anamorph Colletotrichum gloeosporoides) secretes high levels of an FAD-dependent glucose dehydrogenase (GDH) when grown on tomato juice supplemented media. To elucidate its molecular and catalytic properties, GDH was produced in submerged culture. The highest volumetric activity was obtained in shaking flasks after 6 days of cultivation (3400 U L-1, 4.2% of total extracellular protein). GDH is a monomeric protein with an isoelectric point at pH 5.6. The molecular masses of the glycoforms range from 95 to 135 kDa, but after deglycosylation a single band with 68 kDa was obtained. The absorption spectrum is typical for an FAD-containing enzyme with maxima at 370 and 458 nm... Microbiology journals http://www.medworm.com/rss/comments.php?id=5218772 Thu, 08 Sep 2011 04:00:00 +0100 5218772 http://www.medworm.com/index.php?rid=5218771&cid=s_37896_77_f&fid=37896&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21903758%26dopt%3DAbstract Authors: Chang CY, Hobley L, Till R, Capeness M, Kanna M, Burtt W, Jagtap P, Aizawa SI, Sockett L Abstract Bdellovibrio bacteriovorus grow either predatorily (HD), when they invade the periplasm of another Gram-negative bacterium, exporting into the prey co-ordinated waves of soluble enzymes, using the prey cell contents for growth; or Host-Independently (HI) when they grow (slowly) axenically in rich media. Periplasmic invasion potentially exposes Bdellovibrio to extremes of pH, and the need to scavenge electron donors from prey electron transport components, by synthesis of metalloenzymes. The twin-arginine transport system (Tat) in other bacteria transports folded metalloenzymes and the Bdellovibrio genome encodes 21 potential Tat-transported substrates and Tat transporter prote... Microbiology journals http://www.medworm.com/rss/comments.php?id=5218771 Thu, 08 Sep 2011 04:00:00 +0100 5218771 http://www.medworm.com/index.php?rid=5218781&cid=s_37896_77_f&fid=37896&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21885481%26dopt%3DAbstract Authors: Patrick S, Jobling KL, O'Connor D, Thacker Z, Dryden DT, Blakely GW Abstract In the complete genome sequences of Bacteroides fragilis NCTC9343 and 638R, we have discovered a gene, ubb, the product of which has 63% identity to human ubiquitin and cross-reacts with antibodies raised against bovine ubiquitin. The sequence of ubb is closest in identity (76%) to the ubiquitin gene from a Migratory Grasshopper entomopoxvirus, suggesting acquisition by inter-kingdom horizontal gene transfer. We have screened clinical isolates of B. fragilis from diverse geographical regions and found that ubb is present in some, but not all strains. The gene is transcribed and the mRNA translated in B. fragilis, but deletion of ubb did not have a detrimental effect on growth. BfUbb has a predicte... Microbiology journals http://www.medworm.com/rss/comments.php?id=5218781 Thu, 01 Sep 2011 04:00:00 +0100 5218781 http://www.medworm.com/index.php?rid=5218780&cid=s_37896_77_f&fid=37896&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21885482%26dopt%3DAbstract Authors: Roy S, Honma K, Douglas I, Sharma A, Stafford G Abstract The major bacterial pathogens associated with periodontitis include Tannerella forsythia. We previously discovered that sialic acid stimulates biofilm growth of T. forsythia and that sialidase activity is key to utilisation of sialoconjugate sugars and involved in host-pathogen interactions in vitro. The aim of this work was to assess the influence of the NanH sialidase on initial biofilm adhesion and growth in experiments where the only source of sialic acid was sialo-glycoproteins or human oral secretions. After showing that T. forsythia can utilise sialo-glycoproteins for biofilm growth we showed that growth and initial adhesion with sialylated mucin and fetuin was inhibited 2-3 fold by the sialidase inhibitor ose... Microbiology journals http://www.medworm.com/rss/comments.php?id=5218780 Thu, 01 Sep 2011 04:00:00 +0100 5218780 http://www.medworm.com/index.php?rid=5175227&cid=s_37896_77_f&fid=37896&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21873404%26dopt%3DAbstract In conclusion, our data confirm the central role of HsiF in the T6SS mechanism, ascertain the predicted HsiF structure and call for reconsideration of gp25-like proteins function. PMID: 21873404 [PubMed - as supplied by publisher] (Source: Microbiology) Microbiology journals http://www.medworm.com/rss/comments.php?id=5175227 Thu, 25 Aug 2011 23:00:00 +0100 5175227 http://www.medworm.com/index.php?rid=5175226&cid=s_37896_77_f&fid=37896&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21873405%26dopt%3DAbstract Authors: Ichikawa M, Minami M, Isaka M, Tatsuno I, Hasegawa T Abstract The virulence of Streptococcus pyogenes depends on proteins that are produced by this bacterium. The production of virulence proteins depends on environmental factors, and two-component regulatory systems are considered to be involved in sensing these factors. One of the environmental factors is acid stimuli. We established all speculated two-component regulatory sensor protein knockout strains from the M1 clinical strain of S. pyogenes and examined their relevance to acid stimuli. The parental and its derived knockout strains were cultured in the medium whose pH was adjusted to 7.6 or 6.0, and their growth in broth was compared. The spy1622 sensor knockout strain showed significant growth reduction compared to ... Microbiology journals http://www.medworm.com/rss/comments.php?id=5175226 Thu, 25 Aug 2011 23:00:00 +0100 5175226 http://www.medworm.com/index.php?rid=5175225&cid=s_37896_77_f&fid=37896&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21873406%26dopt%3DAbstract Authors: Knetsch CW, Hensgens MP, Harmanus C, van der Bijl MW, Savelkoul PH, Kuijper EJ, Corver J, van Leeuwen HC Abstract Rapid identification of hypervirulent Clostridium difficile strains is essential for preventing the spread of these strains. Recent completion of several full-length C. difficile genomes provided an excellent opportunity to identify potential unique genes that characterize hypervirulent strains. Based on sequence comparisons between C. difficile strains we describe two gene insertions into the genome of hypervirulent PCR ribotypes 078 and 027. Analysis of these regions, of 1.7kb and 4.2kb respectively, revealed that they contain several interesting open reading frames. The 078-region is inserted intergenically and introduces an enzyme that is involved in the bi... Microbiology journals http://www.medworm.com/rss/comments.php?id=5175225 Thu, 25 Aug 2011 23:00:00 +0100 5175225 http://www.medworm.com/index.php?rid=5175224&cid=s_37896_77_f&fid=37896&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21873407%26dopt%3DAbstract In conclusion, it is evident that DctP protein is a mannose-sensitive haemagglutinin, a virulence factor and involved in the utilization of sialic acid. PMID: 21873407 [PubMed - as supplied by publisher] (Source: Microbiology) Microbiology journals http://www.medworm.com/rss/comments.php?id=5175224 Thu, 25 Aug 2011 23:00:00 +0100 5175224 http://www.medworm.com/index.php?rid=5175223&cid=s_37896_77_f&fid=37896&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21873408%26dopt%3DAbstract This study presents the novel finding that the Pseudomonas aeruginosa response to limiting oxygen stress includes induction of its Type III Secretion System (T3SS) which subsequently contributes towards host cell cytotoxicity. In P. aeruginosa the global anaerobic response regulator Anr perceives low oxygen and subsequently triggers gene expression of a range of target genes including the response regulator narL. Here we demonstrate that microaerobic induction of the T3SS is dependent on Anr and this is mediated through direct NarL transcriptional repression of the sRNAs rsmY and rsmZ allowing free RsmA protein to positively regulate the T3SS. This study reveals novel interplay between the Anr-NarL and RsmAYZ regulatory circuits and introduces RsmA as an important regulator during P. aerug... Microbiology journals http://www.medworm.com/rss/comments.php?id=5175223 Thu, 25 Aug 2011 23:00:00 +0100 5175223 http://www.medworm.com/index.php?rid=5175222&cid=s_37896_77_f&fid=37896&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21873409%26dopt%3DAbstract Authors: Gaballa A, Helmann JD Abstract Identification of genes regulated by the ferric uptake regulator (Fur) protein has provided insights into the diverse mechanisms of adaptation to iron limitation. In the soil bacterium Bacillus subtilis, Fur senses iron sufficiency and represses genes enabling iron uptake including biosynthetic and transport genes for the siderophore bacillibactin and uptake systems for siderophores produced by other organisms. We here demonstrate that Fur regulates hmoA (formerly yetG) which encodes a heme monooxygenase. HmoA is the first characterized member of a divergent group of putative monooxygenases that cluster separately from the well characterized IsdG family. B. subtilis also encodes an IsdG family protein designated HmoB (formerly YhgC). Unlike h... Microbiology journals http://www.medworm.com/rss/comments.php?id=5175222 Thu, 25 Aug 2011 23:00:00 +0100 5175222 http://www.medworm.com/index.php?rid=5175221&cid=s_37896_77_f&fid=37896&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21873410%26dopt%3DAbstract Authors: Gruber S, Seidl-Seiboth V Abstract Lysis of the prey's cell wall is one of the key steps during mycoparasitism. Genome analysis of two mycoparasitic Trichoderma spp., T. atroviride and T. virens, revealed an expanded arsenal of genes encoding enzymes potentially involved in cell wall hydrolysis. Glycoside hydrolase family 18, which contains all fungal chitinases, is the largest family of carbohydrate-active enzymes in mycoparasitic Trichoderma species. However, in addition to their aggressive functions during mycoparasitism the roles of chitinases and other cell wall degrading enzymes include also remodelling and recycling of the fungus' own cell wall. In this review we discuss the current knowledge about fungal cell wall degrading enzymes in Trichoderma and how the fungus... Microbiology journals http://www.medworm.com/rss/comments.php?id=5175221 Thu, 25 Aug 2011 23:00:00 +0100 5175221 http://www.medworm.com/index.php?rid=5157200&cid=s_37896_77_f&fid=37896&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21852347%26dopt%3DAbstract Authors: Brotman Y, Lisec J, Méret M, Chet I, Willmitzer L, Viterbo A Abstract In the present study we have assessed, by transcriptional and metabolic profiling, the systemic defense response of Arabidopsis thaliana plants to the leaf pathogen Pseudomonas syringae pv. tomato DC3000 (Pst) induced by the beneficial fungus Trichoderma asperelloides T203.Expression analysis (qPCR) of a set of 137 Arabidopsis genes related to Pst defense responses showed that T203 root colonization is not associated with major detectable transcriptomic changes in leaves. However, plants challenged with the bacterial pathogen showed quantitative differences in gene expression when pre-inoculated by T203, supporting priming of the plant by this beneficial fungus. Among the defense related genes affected ... Microbiology journals http://www.medworm.com/rss/comments.php?id=5157200 Wed, 17 Aug 2011 23:00:00 +0100 5157200 http://www.medworm.com/index.php?rid=5157199&cid=s_37896_77_f&fid=37896&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21852348%26dopt%3DAbstract Authors: Lartigue MF, Fribourg Poulard A, Al Safadi R, Pailhories H, Valentin-Domelier AS, Van Der Mee-Marquet N, Rosenau A, Quentin R Abstract Serotype III Group B Streptococcus (GBS) is the major cause of neonatal meningitis, but the risk of infection in the colonized neonates is variable. Capsular sialic acid (Sia), encoded by neu genes, appears to be a major virulence factor in several bacterial species able to reach the cerebrospinal fluid. Therefore, variations of Sia expression related to the genetic diversity of strains may have an impact on the risk of meningitis in colonized neonates. We characterized by MLST the phylogenetic diversity of 64 serotype III GBS strains isolated from vaginal flora and randomly selected. These strains belonged mostly to three major sequences t... Microbiology journals http://www.medworm.com/rss/comments.php?id=5157199 Wed, 17 Aug 2011 23:00:00 +0100 5157199 http://www.medworm.com/index.php?rid=5157198&cid=s_37896_77_f&fid=37896&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21852349%26dopt%3DAbstract In this study we have constructed a ggt deletion mutant in the highly virulent F. tularensis strain, SCHU S4. Characterisation of the mutant strain confirmed the function of ggt, and confirmed the role of γ-glutamyl transpeptidase in cysteine acquisition. The mutant strain was highly attenuated both in vitro and in vivo using murine models of infection. Moreover, we have demonstrated that the attenuated mutant was able to induce protective immunity against a F. tularensis SCHU S4 challenge, and thus this may be a candidate for development of an attenuated vaccine. PMID: 21852349 [PubMed - as supplied by publisher] (Source: Microbiology) Microbiology journals http://www.medworm.com/rss/comments.php?id=5157198 Wed, 17 Aug 2011 23:00:00 +0100 5157198 http://www.medworm.com/index.php?rid=5157197&cid=s_37896_77_f&fid=37896&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21852350%26dopt%3DAbstract Authors: Wang H, Yang B, Hao G, Feng Y, Chen H, Feng L, Chen YQ, Zhao J, Zhang H, Wang L, Chen W Abstract We characterized the de novo biosynthetic pathway of tetrahydrobiopterin (BH4) in the lipid-producing fungus Mortierella alpina. The BH4 cofactor is essential for various cell processes, and is present in probably every cell or tissue of higher organisms. Genes encoding two copies of GTP cyclohydrolase I (GTPCH-1 and GTPCH-2) for the conversion of GTP to dihydroneopterin triphosphate (H2-NTP), 6-pyruvoyltetrahydropterin synthase (PTPS) for the conversion of H2-NTP to 6-pyruvoyltetrahydropterin (PPH4), and sepiapterin reductase (SR) for the conversion of PPH4 to BH4 were expressed heterologously in Escherichia coli. The recombinant enzymes were produced as His-tagged fusion prot... Microbiology journals http://www.medworm.com/rss/comments.php?id=5157197 Wed, 17 Aug 2011 23:00:00 +0100 5157197 http://www.medworm.com/index.php?rid=5157196&cid=s_37896_77_f&fid=37896&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21852351%26dopt%3DAbstract Authors: Dwyer BE, Newton KL, Kisiela D, Sokurenko EV, Clegg S Abstract Type 1 fimbriae produced by serovars of Salmonella are characterized by their ability to agglutinate guinea pig erythrocytes in the absence of D-mannose but not in its presence. The FimH protein is the adhesin that mediates this reaction and is distinct from the major fimbrial protein (FimA) that comprises the fimbrial shaft. Avian-adapted serovars of Salmonella produce non-haemagglutinating fimbriae that have been reported to mediate adherence to avian cells. A single amino acid substitution is present in the FimH adhesin of these strains compared to that of a Typhimurium isolate. Also, previous studies have shown that single nucleotide polymorphisms in two strains of the Typhimurium fimH have been found to al... Microbiology journals http://www.medworm.com/rss/comments.php?id=5157196 Wed, 17 Aug 2011 23:00:00 +0100 5157196 http://www.medworm.com/index.php?rid=5157195&cid=s_37896_77_f&fid=37896&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21852352%26dopt%3DAbstract Authors: Dong J, Signo KS, Vanderlinde EM, Yost CK, Dahms T Abstract Atomic force microscopy was used to investigate the surface ultrastructure, adhesive properties, and biofilm formation of Rhizobium leguminosarum and a ctpA mutant strain. The surface ultrastructure of wild type R. leguminosarum consists of tightly packed surface subunits, whereas the ctpA mutant has much larger subunits with loose lateral packing. The ctpA mutant strain is not capable of developing fully mature biofilms, consistent with its altered surface ultrastructure, greater roughness and stronger adhesion to hydrophilic surfaces. For both strains, surface roughness and adhesive forces increased as a function of calcium ion concentration, and for each, biofilms were thicker at higher calcium concentrations. ... Microbiology journals http://www.medworm.com/rss/comments.php?id=5157195 Wed, 17 Aug 2011 23:00:00 +0100 5157195 http://www.medworm.com/index.php?rid=5098434&cid=s_37896_77_f&fid=37896&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21816878%26dopt%3DAbstract Authors: Ningsih F, Kitani S, Fukushima E, Nihira T A streptogramin type B antibiotic, virginiamycin S (VS), is produced by Streptomyces virginiae, together with a streptogramin type A antibiotic, virginiamycin M1 (VM), as its synergistic counterpart. VS is a cyclic hexadepsipeptide containing a nonproteinogenic amino acid, L-phenylglycine (PheGly), in its core structure. We have identified, in the left-hand extremity of the virginiamycin supercluster, two genes that direct VS biosynthesis with PheGly incorporation. Transcriptional analysis revealed that visF encoding a nonribosomal peptide synthetase and visG encoding a protein with homology to a hydroxyphenylacetyl-CoA dioxygenase are under the transcriptional regulation of VB, a small diffusing signaling molecule, which governs virg... Microbiology journals http://www.medworm.com/rss/comments.php?id=5098434 Wed, 03 Aug 2011 23:00:00 +0100 5098434 http://www.medworm.com/index.php?rid=5098433&cid=s_37896_77_f&fid=37896&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21816879%26dopt%3DAbstract Authors: Kamerewerd J, Zadra I, Kürnsteiner H, Kück U Penicillin production in Penicillium chrysogenum is controlled by PcVelA and PcLaeA, two components of the regulatory velvet-like complex. Comparative microarray analysis with mutants lacking PcVelA or PcLaeA revealed a set of 62 common genes affected by the loss of both components. A down-regulated gene in both knockout strains is PcchiBI, potentially encoding a class V chitinase. Under nutrient depleted conditions, transcript levels of PcchiBI are strongly up-regulated, and the gene product contributes to more than 50% of extracellular chitinase activity. Functional characterization by generating PcchiBI disruption strains revealed that PcChiBI is responsible for cell wall integrity and pellet formation in P. chrysogenum. Furthe... Microbiology journals http://www.medworm.com/rss/comments.php?id=5098433 Wed, 03 Aug 2011 23:00:00 +0100 5098433 http://www.medworm.com/index.php?rid=5098432&cid=s_37896_77_f&fid=37896&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21816880%26dopt%3DAbstract In this study we report RNA-seq analyses of the transcriptomes of C. jejuni (NCTC11168), and its rpoN mutant. This has allowed the identification of hitherto unknown transcriptional units, and further defines the regulon that is dependent on rpoN for expression. The analysis of the NCTC11168 transcriptome was supplemented by additional proteomic analysis using liquid chromatography mass spectrometry (LC-MS). The transcriptomic and proteomic datasets represent an important resource for the Campylobacter research community. PMID: 21816880 [PubMed - as supplied by publisher] (Source: Microbiology) Microbiology journals http://www.medworm.com/rss/comments.php?id=5098432 Wed, 03 Aug 2011 23:00:00 +0100 5098432 http://www.medworm.com/index.php?rid=5098431&cid=s_37896_77_f&fid=37896&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21816881%26dopt%3DAbstract Authors: Dar HH, Prasad D, Varshney GC, Chakraborti PK Nucleoside diphosphate kinase (NDK), responsible for the maintenance of NTP pools, is an ATP utilizing enzyme secreted by different pathogens. We found that NDK from Salmonella enterica serovar typhimurium is also secretory in nature. Secretory NDK is known to play a crucial role in the survival of pathogenic microbes within host cells through their interaction with extracellular-ATP. To elucidate this aspect, we assessed the contribution of secretory products containing NDK from intra-cellular (M. tuberculosis and S. typhimurium) or extra-cellular (V. cholerae) pathogens in the process of ATP-induced J774 mouse macrophage cell lysis by monitoring lactate dehydrogenase (LDH) release in the culture medium. Compared to untreated cont... Microbiology journals http://www.medworm.com/rss/comments.php?id=5098431 Wed, 03 Aug 2011 23:00:00 +0100 5098431 http://www.medworm.com/index.php?rid=5098430&cid=s_37896_77_f&fid=37896&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21816882%26dopt%3DAbstract Authors: Kajfasz JK, Abranches J, Lemos JA The ClpXP proteolytic complex is critical for maintaining cellular homeostasis, as well as expression of virulence properties. However, with the exception of the Spx global regulator, the molecular mechanisms by which the ClpXP complex exerts its influence in Streptopcoccus mutans are not well understood. Here, microarray analysis was used to provide novel insights into the scope of ClpXP proteolysis in S. mutans. In the clpP strain, 288 genes showed significant changes in relative transcript amounts (p ≤ 0.001, 2-fold cutoff) as compared to the parent. Similarly, 242 genes were differentially expressed by ΔclpX, 113 (47%) of which also appeared in the ΔclpP microarrays. Several genes associated with cell growth were downregulated in both ... Microbiology journals http://www.medworm.com/rss/comments.php?id=5098430 Wed, 03 Aug 2011 23:00:00 +0100 5098430 http://www.medworm.com/index.php?rid=5098438&cid=s_37896_77_f&fid=37896&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21798981%26dopt%3DAbstract Authors: Li X, McInerney MJ, Stahl D, Krumholz L Syntrophic growth involves the oxidation of organic compounds and subsequent transfer of electrons to a H2- or formate-consuming microorganism. In order to identify genes specifically involved in syntrophic growth, a mutant library of Desulfovibrio desulfuricans G20 was screened for loss of the ability to grow syntrophically with Methanospirillum hungatei. A collection of twenty mutants with an impaired ability to grow syntrophically was obtained. All twenty mutants grew in pure culture on lactate under sulfidogenic conditions at a similar rate and to a similar maximum OD600 as the parent strain. The largest number of mutations that affected syntrophic growth with lactate was in genes encoding proteins involved in H2 oxidation, electron ... Microbiology journals http://www.medworm.com/rss/comments.php?id=5098438 Wed, 27 Jul 2011 23:00:00 +0100 5098438