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 'Archives of Microbiology' source. Mon, 06 Feb 2012 21:32:06 +0100 http://www.medworm.com/index.php?rid=5658891&cid=s_37326_77_f&fid=37326&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22290290%26dopt%3DAbstract This study suggests that bacteriocins can be an effective way to control surface-attached pathogenic bacteria. PMID: 22290290 [PubMed - as supplied by publisher] (Source: Archives of Microbiology) Archives of Microbiology journals http://www.medworm.com/rss/comments.php?id=5658891 Tue, 31 Jan 2012 05:00:00 +0100 5658891 http://www.medworm.com/index.php?rid=5658892&cid=s_37326_77_f&fid=37326&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22286926%26dopt%3DAbstract Authors: Kempher ML, Madigan MT Abstract Norbert Pfennig isolated the first acidophilic purple bacterium over 40 years ago and named the organism Rhodopseudomonas acidophila (now Rhodoblastus acidophilus). Since the original work of Pfennig, no systematic study has been conducted on the phylogeny and carbon nutrition of a collection of strains of Rbl. acidophilus. We have isolated six new strains of Rbl. acidophilus from a Canadian peat bog. These strains, three of the original Pfennig strains and two additional putative R. acidophilus strains isolated several years ago in this laboratory, were characterized as to their pigments, phylogeny, and carbon sources supporting photoheterotrophic growth. Phototrophic cultures were either purple or orange in color, and the color of a parti... Archives of Microbiology journals http://www.medworm.com/rss/comments.php?id=5658892 Sun, 29 Jan 2012 05:00:00 +0100 5658892 http://www.medworm.com/index.php?rid=5639133&cid=s_37326_77_f&fid=37326&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22278765%26dopt%3DAbstract Role of anionic charges of osmoregulated periplasmic glucans of Salmonella enterica serovar Typhimurium SL1344 in mice virulence. Arch Microbiol. 2012 Jan 26; Authors: Bhagwat AA, Kannan P, Leow YN, Dharne M, Smith A Abstract opgB gene of Salmonella enterica serovar Typhimurium was identified earlier in a genome-wide screen for mice virulence (Valentine et al. in Infect Immun 66:3378-3383, 1998). Although mutation in opgB resulted in avirulent Salmonella strain, how this gene contributes to pathogenesis remains unclear. Based on DNA homology, opgB is predicted to be responsible for adding phosphoglycerate residues to osmoregulated periplasmic glucans (OPGs) giving them anionic characteristics. In Escherichia coli, yet another gene, opgC, is also... Archives of Microbiology journals http://www.medworm.com/rss/comments.php?id=5639133 Thu, 26 Jan 2012 05:00:00 +0100 5639133 http://www.medworm.com/index.php?rid=5639134&cid=s_37326_77_f&fid=37326&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22273979%26dopt%3DAbstract Authors: Sekot G, Posch G, Oh YJ, Zayni S, Mayer HF, Pum D, Messner P, Hinterdorfer P, Schäffer C Abstract The Gram-negative oral pathogen Tannerella forsythia is decorated with a 2D crystalline surface (S-) layer, with two different S-layer glycoprotein species being present. Prompted by the predicted virulence potential of the S-layer, this study focused on the analysis of the arrangement of the individual S-layer glycoproteins by a combination of microscopic, genetic, and biochemical analyses. The two S-layer genes are transcribed into mRNA and expressed into protein in equal amounts. The S-layer was investigated on intact bacterial cells by transmission electron microscopy, by immune fluorescence microscopy, and by atomic force microscopy. The analyses of wild-type cells revea... Archives of Microbiology journals http://www.medworm.com/rss/comments.php?id=5639134 Wed, 25 Jan 2012 05:00:00 +0100 5639134 http://www.medworm.com/index.php?rid=5639135&cid=s_37326_77_f&fid=37326&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22245906%26dopt%3DAbstract Authors: Li D, Midgley DJ, Ross JP, Oytam Y, Abell GC, Volk H, Daud WA, Hendry P Abstract Microbial diversity within formation water and oil from two compartments in Bokor oil reservoir from a Malaysian petroleum oil field was examined. A total of 1,056 16S rRNA gene clones were screened from each location by amplified ribosomal DNA restriction analysis. All samples were dominated by clones affiliated with Marinobacter, some novel Deferribacteraceae genera and various clones allied to the Methanococci. In addition, either Marinobacterium- or Pseudomonas-like operational taxonomic units were detected from either compartment. A systematic comparison with the existing pertinent studies was undertaken by analysing the microbial amplicons detected and the PCR primers used. The analyses ... Archives of Microbiology journals http://www.medworm.com/rss/comments.php?id=5639135 Fri, 13 Jan 2012 05:00:00 +0100 5639135 http://www.medworm.com/index.php?rid=5639136&cid=s_37326_77_f&fid=37326&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22234847%26dopt%3DAbstract Authors: Shippy DC, Heintz JA, Albrecht RM, Eakley NM, Chopra AK, Fadl AA PMID: 22234847 [PubMed - as supplied by publisher] (Source: Archives of Microbiology) Archives of Microbiology journals http://www.medworm.com/rss/comments.php?id=5639136 Wed, 11 Jan 2012 05:00:00 +0100 5639136 http://www.medworm.com/index.php?rid=5639138&cid=s_37326_77_f&fid=37326&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22231476%26dopt%3DAbstract Authors: Patin D, Bostock J, Chopra I, Mengin-Lecreulx D, Blanot D Abstract Chlamydiaceae are obligate intracellular bacteria that do not synthesise detectable peptidoglycan although they possess an almost complete arsenal of genes encoding peptidoglycan biosynthetic activities. In this paper, the murF gene from Chlamydia trachomatis was shown to be capable of complementing a conditional Escherichia coli mutant impaired in UDP-MurNAc-tripeptide:D: -Ala-D: -Ala ligase activity. Recombinant MurF from C. trachomatis was overproduced and purified from E. coli. It exhibited ATP-dependent UDP-MurNAc-X-γ-D: -Glu-meso-A(2)pm:D: -Ala-D: -Ala ligase activity in vitro. No significant difference of kinetic parameters was seen when X was L: -Ala, L: -Ser or Gly. The L: -Lys-containing UDP-MurN... Archives of Microbiology journals http://www.medworm.com/rss/comments.php?id=5639138 Tue, 10 Jan 2012 05:00:00 +0100 5639138 http://www.medworm.com/index.php?rid=5639137&cid=s_37326_77_f&fid=37326&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22231477%26dopt%3DAbstract In this study, the in-frame rpoN deletion mutant was constructed to analyze the function of RpoN in Edwardsiella tarda firstly. Compared to the wild-type and complemented strain rpoN (+), the ΔrpoN was impaired in terms of the ability to survive under oxidative stress, osmotic stress and acid resistance, as well as the growth in Luria-Bertani medium, demonstrating essential roles of RpoN in stress resistance and nitrogen utilization. In addition, the ΔrpoN displayed markedly decreased biofilm formation and chondroitinase activity and was attenuated in virulence reflected in the increased median lethal dose value and extended infection cycle. Real-time polymerase chain reaction revealed that the expression levels of σ(70) class changed in varying degrees in the rpoN mutant. Esp... Archives of Microbiology journals http://www.medworm.com/rss/comments.php?id=5639137 Tue, 10 Jan 2012 05:00:00 +0100 5639137 http://www.medworm.com/index.php?rid=5578069&cid=s_37326_77_f&fid=37326&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22228487%26dopt%3DAbstract In conclusion, increased salinities caused decreased nitrogenase activity and were accompanied by a lower proportion of cyanobacterial nifH transcripts. PMID: 22228487 [PubMed - as supplied by publisher] (Source: Archives of Microbiology) Archives of Microbiology journals http://www.medworm.com/rss/comments.php?id=5578069 Sun, 08 Jan 2012 05:00:00 +0100 5578069 http://www.medworm.com/index.php?rid=5578071&cid=s_37326_77_f&fid=37326&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22228442%26dopt%3DAbstract Authors: Liang Y, Gao H, Guo X, Chen J, Qiu G, He Z, Zhou J, Liu X Abstract Although the pellicle is one of the major growth modes of microorganisms, the metabolic features of pellicle cells and the determinative factors for pellicle formation are largely unknown. In recent years, biofilm development of Shewanella oneidensis, an important model organism for bioremediation studies, has been extensively studied. In this paper, a transcriptional profiling of pellicle cells relative to planktonic cells indicated that cells in pellicles were more metabolically active than the planktonic cells. Most notably, up-transcription of general secretion system proteins and iron/heme uptake and transport proteins was observed in pellicle cells. Unexpectedly, neither the hmuT nor hugA heme transpo... Archives of Microbiology journals http://www.medworm.com/rss/comments.php?id=5578071 Sat, 07 Jan 2012 05:00:00 +0100 5578071 http://www.medworm.com/index.php?rid=5578070&cid=s_37326_77_f&fid=37326&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22228443%26dopt%3DAbstract Authors: Strazdina I, Kravale Z, Galinina N, Rutkis R, Poole RK, Kalnenieks U Abstract The ethanol-producing bacterium Zymomonas mobilis is of great interest from a bioenergetic perspective because, although it has a very high respiratory capacity, the respiratory system does not appear to be primarily required for energy conservation. To investigate the regulation of respiratory genes and function of electron transport branches in Z. mobilis, several mutants of the common wild-type strain Zm6 (ATCC 29191) were constructed and analyzed. Mutant strains with a chloramphenicol-resistance determinant inserted in the genes encoding the cytochrome b subunit of the bc (1) complex (Zm6-cytB), subunit II of the cytochrome bd terminal oxidase (Zm6-cydB), and in the catalase gene (Z... Archives of Microbiology journals http://www.medworm.com/rss/comments.php?id=5578070 Sat, 07 Jan 2012 05:00:00 +0100 5578070 http://www.medworm.com/index.php?rid=5549606&cid=s_37326_77_f&fid=37326&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22200863%26dopt%3DAbstract Authors: Blanco G Abstract In silico database searches allowed the identification in the S. flavogriseus ATCC 33331 genome of a carbapenem gene cluster highly related to the S. cattleya thienamycin one. This is the second cluster found for a complex highly substituted carbapenem. Comparative analysis revealed that both gene clusters display a high degree of synteny in gene organization and in protein conservation. Although the cluster appears to be silent under our laboratory conditions, the putative metabolic product was predicted from bioinformatics analyses using sequence comparison tools. These data, together with previous reports concerning epithienamycins production by S. flavogriseus strains, suggest that the cluster metabolic product might be a thienamycin-like carbapenem, ... Archives of Microbiology journals http://www.medworm.com/rss/comments.php?id=5549606 Tue, 27 Dec 2011 05:00:00 +0100 5549606 http://www.medworm.com/index.php?rid=5513089&cid=s_37326_77_f&fid=37326&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22173827%26dopt%3DAbstract Authors: Vajrala N, Sayavedra-Soto LA, Bottomley PJ, Arp DJ Abstract The importance of iron to the metabolism of the ammonia-oxidizing bacterium Nitrosomonas europaea is well known. However, the mechanisms by which N. europaea acquires iron under iron limitation are less well known. To obtain insight into these mechanisms, transcriptional profiling of N. europaea was performed during growth under different iron availabilities. Of 2,355 N. europaea genes on DNA microarrays, transcripts for 247 genes were identified as differentially expressed when cells were grown under iron limitation compared to cells grown under iron-replete conditions. Genes with higher transcript levels in response to iron limitation included those with confirmed or assigned roles in iron acquisition. Genes wit... Archives of Microbiology journals http://www.medworm.com/rss/comments.php?id=5513089 Fri, 16 Dec 2011 05:00:00 +0100 5513089 http://www.medworm.com/index.php?rid=5513088&cid=s_37326_77_f&fid=37326&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22173828%26dopt%3DAbstract In this study, we characterized in vitro and in vivo the BaeSR two-component system from Salmonella Typhimurium and evaluated its role in mdtA regulation in response to ciprofloxacin treatment. We demonstrated in vitro that residue histidine 250 is essential for BaeS autophosphorylation and aspartic acid 61 for BaeR transphosphorylation. By real-time PCR, we showed that mdtA activation in the presence of ciprofloxacin depends on both members of this system and that histidine 250 of BaeS and aspartic acid 61 of BaeR are needed for this. Moreover, the mdtA expression is directly regulated by binding of BaeR at the promoter region, and this interaction is enhanced when the protein is phosphorylated. In agreement, a BaeR mutant unable to phosphorylate at aspartic acid 61 presents a lower affin... Archives of Microbiology journals http://www.medworm.com/rss/comments.php?id=5513088 Fri, 16 Dec 2011 05:00:00 +0100 5513088 http://www.medworm.com/index.php?rid=5513087&cid=s_37326_77_f&fid=37326&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22173829%26dopt%3DAbstract In this study, expression of a hemolysin coregulated protein (Hcp1), which is one of the hallmarks of T6SS, was found to be strictly regulated in this bacterium. We showed that the expression of Hcp1 was growth phase-dependent and the production of Hcp1 reached a maximum in the exponential phase. The expression of Hcp1 was positively and negatively regulated by quorum sensing regulators LuxO and LuxR, respectively. In addition, we observed that Hcp1 expression required the alternative sigma factor RpoN and the enhancer-binding protein VasH, which is encoded in T6SSVA1 gene cluster. Moreover, LuxR, RpoN, and VasH could positively regulate the expression of other T6SS genes. Taken together, we demonstrated that the expression of T6SS in V. alginolyticus was under the regulation of quorum sen... Archives of Microbiology journals http://www.medworm.com/rss/comments.php?id=5513087 Fri, 16 Dec 2011 05:00:00 +0100 5513087 http://www.medworm.com/index.php?rid=5513090&cid=s_37326_77_f&fid=37326&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22159868%26dopt%3DAbstract Authors: Pujic P, Fournier P, Alloisio N, Hay AE, Maréchal J, Anchisi S, Normand P Abstract Frankia alni strain ACN14a's genome was scanned for the presence of determinants involved in interactions with its host plant, Alnus spp. One such determinant type is lectin, proteins that bind specifically to sugar motifs. The genome of F. alni was found to contain 7 such lectin-coding genes, five of which were of the ricinB-type. The proteins coded by these genes contain either only the lectin domain, or also a heat shock protein or a serine-threonine kinase domain upstream. These lectins were found to have several homologs in Streptomyces spp., and a few in other bacterial genomes among which none in Frankia EAN1pec and CcI3 and two in strain EUN1f. One of these F. alni genes, FRAAL0616,... Archives of Microbiology journals http://www.medworm.com/rss/comments.php?id=5513090 Thu, 08 Dec 2011 05:00:00 +0100 5513090 http://www.medworm.com/index.php?rid=5513091&cid=s_37326_77_f&fid=37326&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22134432%26dopt%3DAbstract Authors: Stone BL, White AK Abstract Concentrations of hypophosphite and phosphite oxidizing bacteria were found to be high, relative to bacterial concentrations growing on phosphate, in sediment and soil during winter and summer seasons from 12 common terrestrial and aquatic sites using a most probable number method. The percent of total culturable bacterial concentrations that could use these reduced phosphorus compounds as a sole source of phosphorus were as follows: hypophosphite, 7-100%; phosphite, 10-67%; aminoethylphosphonate, 34-270%. The average MPN/g (±SEM) was as follows: phosphate, 6.19 × 10(6) (±2.40 × 10(6)); hypophosphite, 2.61 × 10(6) (±1.35 × 10(6)) phosphite, 1.91 × 10(6) (±1.02 × 10(6)); aminoethylphosphonate, 3.90 × 10(6) (± 1.95 × 1... Archives of Microbiology journals http://www.medworm.com/rss/comments.php?id=5513091 Fri, 02 Dec 2011 05:00:00 +0100 5513091 http://www.medworm.com/index.php?rid=5513093&cid=s_37326_77_f&fid=37326&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22130678%26dopt%3DAbstract In this study, a new TetR family QS regulator, luxT, was identified and characterized in V. alginolyticus. The transcription of luxT gene was cell density dependent and was positively regulated by LuxU, an established QS component relaying the signal from three paralleled QS regulatory systems in V. harveyi. In addition, luxT positively regulated both luxO at transcriptional level and luxR at post-transcriptional level, which is thoroughly different from the established QS regulation mode in V. harveyi and Vibrio vulnificus. The mutant of luxT deletion produced markedly decreased total extracellular proteases and reduced motility ability compared to the wild type and the complemented strain luxT (+). The fish infection results indicated that mutation of luxT led to marginal atten... Archives of Microbiology journals http://www.medworm.com/rss/comments.php?id=5513093 Thu, 01 Dec 2011 05:00:00 +0100 5513093 http://www.medworm.com/index.php?rid=5513092&cid=s_37326_77_f&fid=37326&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22130679%26dopt%3DAbstract Authors: Santos CL, Tavares F PMID: 22130679 [PubMed - as supplied by publisher] (Source: Archives of Microbiology) Archives of Microbiology journals http://www.medworm.com/rss/comments.php?id=5513092 Thu, 01 Dec 2011 05:00:00 +0100 5513092 http://www.medworm.com/index.php?rid=5455497&cid=s_37326_77_f&fid=37326&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22113351%26dopt%3DAbstract Authors: Eigentler A, Pócsi I, Marx F Abstract In the genome of Aspergillus nidulans, a defensin-like protein, Anisin1, was annotated with high homology to the mosquito defensin AaDefA1. So far, no studies exist on defensins from filamentous ascomycetes. Therefore, we characterized the anisin1 gene in A. nidulans and generated a deletion mutant, which suffered from a defect in mitospore development and produced less conidia at 42°C compared to the reference strain. In surface cultures of A. nidulans wild type, the anisin1 expression correlated with that of the central regulator for asexual development, brlA, and with the major scavanger of H(2)O(2) stress, catB, which is indicative for cell differentiation in developing fungi. Interestingly, brlA and anisin1 expressions were dere... Archives of Microbiology journals http://www.medworm.com/rss/comments.php?id=5455497 Thu, 24 Nov 2011 05:00:00 +0100 5455497 http://www.medworm.com/index.php?rid=5455500&cid=s_37326_77_f&fid=37326&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22109812%26dopt%3DAbstract Authors: Yu Q, Du A, Liu T, Deng Z, He X Abstract The nanchangmycin (NAN) produced by Streptomyces nanchangensis NS3226 is a polyether antibiotic resembling monensin in their gene clusters and the chemical structures. They can inhibit gram-positive bacteria and be a growth promoter for ruminants. Within the nanchangmycin gene cluster (nan), we identified that two SARP-family regulatory genes, nanR1 and nanR2, were both required to activate the transcription of all nan polyketide genes. Overexpression of NanR1 and NanR2 in wild-type increase NAN yields by at least three folds. Bioinformatic analysis of the immediate upstream DNA sequence of each nan gene and quantitative real-time RT-PCR analysis of the nan operons identified five putative SARP binding sites. Moreover, deletion of a... Archives of Microbiology journals http://www.medworm.com/rss/comments.php?id=5455500 Wed, 23 Nov 2011 05:00:00 +0100 5455500 http://www.medworm.com/index.php?rid=5455499&cid=s_37326_77_f&fid=37326&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22109813%26dopt%3DAbstract Authors: Shippy DC, Heintz JA, Albrecht RM, Eakley NM, Fadl AA Abstract Salmonella is an important food-borne pathogen that continues to plague the United States food industry. Characterization of bacterial factors involved in food-borne illnesses could help develop new ways to control salmonellosis. We have previously shown that deletion of glucose-inhibited division gene (gidA) significantly altered the virulence potential of Salmonella in both in vitro and in vivo models of infection. Most importantly, the gidA mutant cells displayed a filamentous morphology compared to the wild-type Salmonella cells. In our current study, we investigated the role of GidA in Salmonella cell division using fluorescence and electron microscopy, transcriptional, and proteomic assays. Scanning elect... Archives of Microbiology journals http://www.medworm.com/rss/comments.php?id=5455499 Wed, 23 Nov 2011 05:00:00 +0100 5455499 http://www.medworm.com/index.php?rid=5455498&cid=s_37326_77_f&fid=37326&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22109814%26dopt%3DAbstract Authors: Sato-Takabe Y, Hamasaki K, Suzuki K PMID: 22109814 [PubMed - as supplied by publisher] (Source: Archives of Microbiology) Archives of Microbiology journals http://www.medworm.com/rss/comments.php?id=5455498 Wed, 23 Nov 2011 05:00:00 +0100 5455498 http://www.medworm.com/index.php?rid=5455501&cid=s_37326_77_f&fid=37326&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22105093%26dopt%3DAbstract Authors: Hibbing ME, Fuqua C Abstract Environmental biofilms often contain mixed populations of different species. In these dense communities, competition between biofilm residents for limited nutrients such as iron can be fierce, leading to the evolution of competitive factors that affect the ability of competitors to grow or form biofilms. We have discovered a compound(s) present in the conditioned culture fluids of Pseudomonas aeruginosa that disperses and inhibits the formation of biofilms produced by the facultative plant pathogen Agrobacterium tumefaciens. The inhibitory activity is strongly induced when P. aeruginosa is cultivated in iron-limited conditions, but it does not function through iron sequestration. In addition, the production of the biofilm inhibitory activity is... Archives of Microbiology journals http://www.medworm.com/rss/comments.php?id=5455501 Tue, 22 Nov 2011 05:00:00 +0100 5455501 http://www.medworm.com/index.php?rid=5455502&cid=s_37326_77_f&fid=37326&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22102083%26dopt%3DAbstract Authors: Nedashkovskaya OI, Van Trappen S, Frolova GM, De Vos P Abstract A bacterial strain, designated KMM 6244(T), was isolated from the sea urchin Strongylocentrotus intermedius and subjected to a polyphasic taxonomic investigation. The bacterium was found to be heterotrophic, aerobic, non-motile and spore-forming. Comparative phylogenetic analysis based on 16S rRNA gene sequencing placed the marine isolate in the genus Bacillus. The nearest neighbor of strain KMM 6244(T) was Bacillus decolorationis LMG 19507(T) with a 16S rRNA gene sequence similarity of 98.0%. Sequence similarities with the other recognized Bacillus species were less than 96.0%. The results of the DNA-DNA hybridization experiments revealed a low relatedness (37%) of the novel isolate with the type strain of B.... Archives of Microbiology journals http://www.medworm.com/rss/comments.php?id=5455502 Sun, 20 Nov 2011 05:00:00 +0100 5455502 http://www.medworm.com/index.php?rid=5419409&cid=s_37326_77_f&fid=37326&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22065311%26dopt%3DAbstract Authors: Qin W, Deng ZS, Xu L, Wang NN, Wei GH Abstract Studying rhizobia in the root nodules of Sphaerophysa salsula (Pall.) DC in the northwest of China, we obtained five strains classified as genus Rhizobium on the basis of their 16S rRNA gene sequences. The sequence similarity of strain CCNWQTX14(T) with the most related species was 99.0%. Further phylogenetic analysis of housekeeping genes (recA and atpD) suggested the five strains comprised a novel lineage within Rhizobium. The nifH and nodD gene sequences of CCNWQTX14(T) were phylogenetically closely related with those of Sinorhizobium kummerowiae and R. sphaerophysae, respectively. The five strains isolated from different places were also distinct from related Rhizobium species using ERIC fingerprint profiles. The DNA-DNA h... Archives of Microbiology journals http://www.medworm.com/rss/comments.php?id=5419409 Wed, 09 Nov 2011 05:00:00 +0100 5419409 http://www.medworm.com/index.php?rid=5379545&cid=s_37326_77_f&fid=37326&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22038095%26dopt%3DAbstract Authors: Naghmouchi K, Hammami R, Fliss I, Teather R, Baah J, Drider D Abstract Recently, we isolated and reported the antagonism of Paenibacillus polymyxa JB05-01-1 (P. polymyxa JB05-01-1) against Gram-negative bacteria. Here, we provide more insights and attribute the abovementioned antagonism to the production of colistins A and B, which were purified by Amberlite column exchange, C18 column hydrophobicity, superdex 75 16/60 gel filtration chromatography connected to fast protein liquid chromatography and identified by MALDI TOF/TOF, and manual nanospray analysis. The amount of colistin A and colistin B recovered from 500 ml of culture supernatant was about 0.05 mg. The specific activity and the average recovery of the eluted substances were 5,120 AU/mg and 1.1%, respectively... Archives of Microbiology journals http://www.medworm.com/rss/comments.php?id=5379545 Sun, 30 Oct 2011 04:00:00 +0100 5379545 http://www.medworm.com/index.php?rid=5379547&cid=s_37326_77_f&fid=37326&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22038025%26dopt%3DAbstract This study aims to investigate the influence of diet roughage proportion on the methanogenic communities from the rumen and fecal samples in Altay local sheep native to Xinjiang and better understand the association of methanogenic diversity or abundance with methane emissions of the ruminants. In this study, the high roughage diet was found to cause more methane emissions for either maintenance or ad-lib group, but the total methanogenic abundance was not influenced by roughage proportion and showed no significant difference between groups. Furthermore, the denaturing gradient gel electrophoresis was conducted to reveal the difference in methanogenic diversity. Phylogenetic analysis showed that the sequences obtained were divided into three groups, affiliated to the genus of Methanobrevib... Archives of Microbiology journals http://www.medworm.com/rss/comments.php?id=5379547 Sat, 29 Oct 2011 04:00:00 +0100 5379547 http://www.medworm.com/index.php?rid=5379546&cid=s_37326_77_f&fid=37326&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22038026%26dopt%3DAbstract Authors: Lal S, Romano S, Chiarini L, Signorini A, Tabacchioni S Abstract Lake Averno sediment was used to isolate the facultative anaerobic bacteria having the potential for H(2) production. Twenty-five out of 35 isolates recovered from the sediment sample produced hydrogen under anaerobic conditions from glucose with yields ranging from 0.1 to 0.49 mol H(2)/mol glucose. Identification based on 16S rRNA gene sequence analysis revealed that most of them belong to the Firmicutes group, with a prevalence of the Paenibacillus polymyxa species. Seven distinct genomic fingerprints among the 11 P. polymyxa isolates were obtained using the random amplified polymorphic DNA (RAPD) technique. Glucose fermentation by P. polymyxa isolates was investigated. Glucose was totally consumed after 3... Archives of Microbiology journals http://www.medworm.com/rss/comments.php?id=5379546 Sat, 29 Oct 2011 04:00:00 +0100 5379546 http://www.medworm.com/index.php?rid=5361039&cid=s_37326_77_f&fid=37326&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22033765%26dopt%3DAbstract Authors: Sato-Takabe Y, Hamasaki K, Suzuki K Abstract A coastal Roseobacter strain of marine aerobic anoxygenic phototrophic bacteria (AAnPB) was isolated and phylogenetically determined. The strain OBYS 0001 was characterized by its physiological and biochemical properties with reference to the Erythrobacter longus type strain NBRC 14126. When grown in batch cultures, the growth curves of the both strains were similar. Cellular bacteriochlorophyll a concentrations of the strains reached the maxima in the stationary growth conditions. In vivo fluorescence excitation/optical density spectra between 470 and 600 nm for OBYS 0001 represented higher values than NBRC 14126. Variable fluorescence measurements revealed that the functional absorption cross section (σ) of the bacterial pho... Archives of Microbiology journals http://www.medworm.com/rss/comments.php?id=5361039 Fri, 28 Oct 2011 04:00:00 +0100 5361039 http://www.medworm.com/index.php?rid=5361038&cid=s_37326_77_f&fid=37326&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22033766%26dopt%3DAbstract In this study, host responses of R. denitrificans OCh114 to phage infection were investigated through in situ real-time atomic force microscopy (AFM) and proteomics approaches. As seen from the AFM observations, during phage infection processes, depression areas appeared on the host cell surface in a few minutes after infection and expanded in both diameter and depth over time and finally led to the collapse of host cells within 30 min. The two-dimensional polyacrylamide gel electrophoresis revealed significant changes in the proteomic composition of the host cells during infection. The expression of 91 proteins, including some involved in DNA transcription regulation and substrate transportation, was changed with at least twofold up- or downregulation as compared to the control without p... Archives of Microbiology journals http://www.medworm.com/rss/comments.php?id=5361038 Fri, 28 Oct 2011 04:00:00 +0100 5361038 http://www.medworm.com/index.php?rid=5344644&cid=s_37326_77_f&fid=37326&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22012026%26dopt%3DAbstract Authors: Bouraoui H, Aissa MB, Abbassi F, Touzel JP, O'donohue M, Manai M Abstract An ultraviolet-radiation-resistant, Gram-positive, orange-pigmented, thermophilic and strictly aerobic cocci was isolated from Saharan water hot spring in Tunisia. The newly isolated bacterium, designated HAN-23(T), was identified based on polyphasic taxonomy including genotypic, phenotypic and chemotaxonomic characterization. Phylogenetic analysis based on 16S rRNA gene sequences placed this strain within Deinococcus genus. However, strain HAN-23(T) is different from recognized species of the genus Deinococcus, showing less than 94.0% similarity values to its closest relatives. The predominant cellular fatty acids determined by gas chromatography were iso-C(15:0), iso-C(17:0) and iso C(17:1) ω9c. T... Archives of Microbiology journals http://www.medworm.com/rss/comments.php?id=5344644 Thu, 20 Oct 2011 04:00:00 +0100 5344644 http://www.medworm.com/index.php?rid=5344645&cid=s_37326_77_f&fid=37326&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22002465%26dopt%3DAbstract Authors: Hsiao YM, Song WL, Liao CT, Lin IH, Pan MY, Lin CF Abstract The nucleotide cyclic di-GMP is a second messenger in bacteria that regulates a range of cellular functions including the virulence of pathogens. GGDEF is a protein domain involved in the synthesis of cyclic di-GMP. The genome of the crucifer pathogen Xanthomonas campestris pv. campestris (Xcc) encodes 21 proteins with a GGDEF domain. Clp, a homolog of the model transcription factor Crp of Escherichia coli, is a global regulator in Xcc. The aim of this study is to identify genes encoding GGDEF domain proteins whose expression is regulated by Clp. Results of reporter assay and RT-PCR analysis suggested that Clp regulates the expression of a set of genes encoding proteins harboring GGDEF domain. The transcription in... Archives of Microbiology journals http://www.medworm.com/rss/comments.php?id=5344645 Sun, 16 Oct 2011 04:00:00 +0100 5344645 http://www.medworm.com/index.php?rid=5344646&cid=s_37326_77_f&fid=37326&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22002406%26dopt%3DAbstract Authors: Grochowski LL, Censky K, Xu H, White RH Abstract The protein derived from the Methanocaldococcus jannaschii MJ0458 gene is annotated as a δ-1-pyrroline 5-carboxylate synthetase and is predicted to be related to aspartokinase and uridylate kinase. Analysis of the predicted protein sequence indicated that it is a unique kinase with few similarities to either uridylate or adenylate kinase. Here, we report that the MJ0458 gene product is a second type of archaeal adenylate kinase, AdkB. This enzyme is different from the established archaeal-specific adenylate kinase in both sequence and predicted tertiary structure. PMID: 22002406 [PubMed - as supplied by publisher] (Source: Archives of Microbiology) Archives of Microbiology journals http://www.medworm.com/rss/comments.php?id=5344646 Sat, 15 Oct 2011 04:00:00 +0100 5344646 http://www.medworm.com/index.php?rid=5344647&cid=s_37326_77_f&fid=37326&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21987378%26dopt%3DAbstract Authors: Li Y, Xiao Y, Zou L, Zou H, Chen G Abstract Xanthomonas oryzae pv. oryzicola is the causal agent of bacterial leaf streak in rice and injects repertoires of T3S effectors (T3SEs), which are normally regulated by a global regulator HrpX, into plant cells to suppress plant innate immunity for disease development. To establish a visualization technique to identify HrpX regulon genes in this pathogen, we chose six known or unknown T3SE genes of X. oryzae pv. oryzicola (strain RS105) as the targets in this report. The promoters of these candidates, whether or not containing a PIP-box, were fused with the gfp (green fluorescent protein) reporter gene, and the gfp reporters were introduced into the wild-type RS105 and the hrpX mutant RΔhrpX. GFP expression in the wild-type strai... Archives of Microbiology journals http://www.medworm.com/rss/comments.php?id=5344647 Tue, 11 Oct 2011 04:00:00 +0100 5344647 http://www.medworm.com/index.php?rid=5344648&cid=s_37326_77_f&fid=37326&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21983836%26dopt%3DAbstract Authors: Fahmy D, Day CJ, Korolik V Abstract Chemoreceptor and chemotaxis signal transduction cascade genes of C. fetus subsp. fetus 82-40 show high level of similarity to that in C. jejuni and appears to include sixteen diverse transducer-like protein (tlp) genes that appear similar to nine of the twelve tlp genes in the C. jejuni NCTC 11168 with a percent identity ranging from 15 to 50%. Sixteen putative C. fetus 82-40 tlp genes belong to three classes: A, B, and C, as well as an aerotaxis gene, based on their predicted structure. C. fetus subsp. fetus 82-40 chemoreceptor and chemotaxis signal transduction pathway genes have close phylogenetic relationship of chemotaxis genes between Campylobacteraceae and Helicobacteraceae. PMID: 21983836 [PubMed - as supplied by publisher] ... Archives of Microbiology journals http://www.medworm.com/rss/comments.php?id=5344648 Sun, 09 Oct 2011 04:00:00 +0100 5344648 http://www.medworm.com/index.php?rid=5296634&cid=s_37326_77_f&fid=37326&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21969032%26dopt%3DAbstract Authors: Bleiholder A, Frommherz R, Teufel K, Pfeifer F Abstract Halobacterium salinarum NRC-1 contains multiple TBP and TFB proteins required for the recruitment of RNA polymerase for transcription initiation. The presence and the expression of genes encoding TFB were investigated in the two Hbt. salinarum strains NRC-1 and PHH1 and the mutant strain PHH4. The plasmid-encoded tfbC and tfbE genes of NRC-1 were lacking in PHH1 and PHH4. The 5'-end of the tfbF transcript was determined and contained a 5'-untranslated region of 39 nucleotides able to form a stem-loop structure. The expression of these tfb genes was studied in cultures growing at 15, 37°C and under heat shock conditions. Cold temperatures reduced growth and except for tfbF also the amounts of all tfb transcripts. Howe... Archives of Microbiology journals http://www.medworm.com/rss/comments.php?id=5296634 Tue, 04 Oct 2011 04:00:00 +0100 5296634 http://www.medworm.com/index.php?rid=5278975&cid=s_37326_77_f&fid=37326&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21960097%26dopt%3DAbstract Authors: Srinivasan V, Morowitz HJ, Huber H Abstract The concept of autotrophy depends on the growth media for pure cultures supplying a single one carbon source for anabolism. Secondary carbon compounds added to the medium as chelators and/or vitamins confuse the meaning. This note suggests a clarification of definition suitable for contemporary biochemical studies of true autotrophs. PMID: 21960097 [PubMed - as supplied by publisher] (Source: Archives of Microbiology) Archives of Microbiology journals http://www.medworm.com/rss/comments.php?id=5278975 Fri, 30 Sep 2011 04:00:00 +0100 5278975 http://www.medworm.com/index.php?rid=5278976&cid=s_37326_77_f&fid=37326&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21947170%26dopt%3DAbstract Authors: Popowska M, Osińska M, Rzeczkowska M Abstract The main aim of our study was to determine the physiological function of NagA enzyme in the Listeria monocytogenes cell. The primary structure of the murein of L. monocytogenes is very similar to that of Escherichia coli, the main differences being amidation of diaminopimelic acid and partial de-N-acetylation of glucosamine residues. NagA is needed for the deacetylation of N-acetyl-glucosamine-6 phosphate to glucosamine-6 phosphate and acetate. Analysis of the L. monocytogenes genome reveals the presence of two proteins with NagA domain, Lmo0956 and Lmo2108, which are cytoplasmic putative proteins. We introduced independent mutations into the structural genes for the two proteins. In-depth characterization of one of these muta... Archives of Microbiology journals http://www.medworm.com/rss/comments.php?id=5278976 Sat, 24 Sep 2011 04:00:00 +0100 5278976 http://www.medworm.com/index.php?rid=5259691&cid=s_37326_77_f&fid=37326&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21938516%26dopt%3DAbstract Authors: Ide M, Ichinose H, Wariishi H Abstract We explored the molecular diversity and functional capabilities of cytochrome P450 monooxygenases (P450s) from the brown-rot basidiomycete Postia placenta. Using bioinformatic and experimental data, we found 250 genes of P450s in the whole genome, including 60 putative allelic variants. Phylogenetic analysis revealed the presence of 42 families, including 18 novel families. Comparative phylogenetic analysis of P450s from P. placenta and the white-rot basidiomycete Phanerochaete chrysosporium suggested that vigorous gene duplication and molecular evolution occurred after speciation of basidiomycetes. Among the 250 gene models, 184 were isolated as full-length cDNA and transformed into Saccharomyces cerevisiae to construct a functional ... Archives of Microbiology journals http://www.medworm.com/rss/comments.php?id=5259691 Thu, 22 Sep 2011 04:00:00 +0100 5259691 http://www.medworm.com/index.php?rid=5218768&cid=s_37326_77_f&fid=37326&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21912976%26dopt%3DAbstract Authors: Mathema VB, Thakuri BC, Sillanpää M Abstract Mercury pollution has emerged as a major problem in industrialized zones and presents a serious threat to environment and health of local communities. Effectiveness and wide distribution of mer operon by horizontal and vertical gene transfer in its various forms among large community of microbe reflect importance and compatibility of this mechanism in nature. This review specifically describes mer operon and its generic molecular mechanism with reference to the central role played by merA gene and its related gene products. The combinatorial action of merA and merB together maintains broad spectrum mercury detoxification system for substantial detoxification of mercurial compounds. Feasibility of mer operon to coexist with ant... Archives of Microbiology journals http://www.medworm.com/rss/comments.php?id=5218768 Tue, 13 Sep 2011 04:00:00 +0100 5218768 http://www.medworm.com/index.php?rid=5218769&cid=s_37326_77_f&fid=37326&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21909805%26dopt%3DAbstract Authors: Vigneshkumar B, Pandian SK, Balamurugan K Abstract The amenability of Caenorhabditis elegans against pathogen provides a valuable tool for studying host-pathogen interactions. Physiological experiments revealed that the P. aeruginosa was able to kill C. elegans efficiently. The effects of P. aeruginosa PA14, PAO1 and their isolated lipopolysaccharide (LPS) on the host system were analyzed. The LPS at higher concentrations (≥2 mg/ml) was toxic to the host animals. Kinetic studies using qPCR revealed the regulation of host-specific candidate antimicrobial genes during pathogen-mediated infections. In addition, the pathogen-specific virulent gene, exoT expression, was anlyzed and found to be varied during the interactions with the host system. Ability of the pathogens to m... Archives of Microbiology journals http://www.medworm.com/rss/comments.php?id=5218769 Sat, 10 Sep 2011 04:00:00 +0100 5218769 http://www.medworm.com/index.php?rid=5218770&cid=s_37326_77_f&fid=37326&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21892611%26dopt%3DAbstract Authors: Roger P, Harn-Arsa S, Delettre J, Béal C Abstract To better understand the phenomena governing the establishment of the oral bacterium Streptococcus salivarius in the mouth, the effect of some environmental factors has been studied in complemented artificial saliva, under oral pH and temperature conditions. Three salivary enzymes at physiological concentrations were tested: peroxidase, lysozyme and amylase, as well as injection of exhaled air. Injection of air containing 5% CO(2) and 16% O(2) induced a deleterious effect on S. salivarius K12, mainly by increasing redox potential. Addition of lysozyme slightly affected the physiological state of S. salivarius by altering membrane integrity. In contrast, peroxidase was not detrimental as it made it possible to decrease the ... Archives of Microbiology journals http://www.medworm.com/rss/comments.php?id=5218770 Sat, 03 Sep 2011 04:00:00 +0100 5218770 http://www.medworm.com/index.php?rid=5192625&cid=s_37326_77_f&fid=37326&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21879294%26dopt%3DAbstract Authors: Kornspan JD, Tarshis M, Rottem S Abstract We demonstrated that when M. pneumoniae was grown on an abiotic surface of either glass or polystyrene with a serum-containing medium, the bacteria adhered to the surface and formed highly differentiated volcano-like biofilm structures. As adherence to the surface and/or biofilm formation was totally inhibited by anti-P1 polyclonal monospecific antibodies, we suggest that the adherence of M. pneumoniae to the abiotic surface and/or biofilm formation is associated with P1, the major tip organelle protein of this organism. Furthermore, adherence and/or biofilm formation was markedly inhibited by treating the serum component of the growth medium with neuraminidase or by growing the bacteria in the presence of sialyllactose, suggesting... Archives of Microbiology journals http://www.medworm.com/rss/comments.php?id=5192625 Tue, 30 Aug 2011 23:00:00 +0100 5192625 http://www.medworm.com/index.php?rid=5157191&cid=s_37326_77_f&fid=37326&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21861152%26dopt%3DAbstract Authors: Furnholm T, Beauchemin N, Tisa LS Abstract Filamentous bacteria pose unique challenges for testing multiple variables or growth parameters limiting the use of high-throughput methods. A semi-high-throughput growth assay system was developed to overcome these obstacles and validated for the filamentous actinobacteria Frankia. The 24-well plate assay was versatile for testing multiple growth medium parameters and provided reproducible results across wells and between plates. Under conditions of increased complexity, statistical analysis demonstrated that the variance was dependent on the experimental parameters and not the assay system. The 24-well plate assay was shown to be multipurpose for testing numerous variables on cell growth or other biological properties. PMID:... Archives of Microbiology journals http://www.medworm.com/rss/comments.php?id=5157191 Mon, 22 Aug 2011 23:00:00 +0100 5157191 http://www.medworm.com/index.php?rid=5157190&cid=s_37326_77_f&fid=37326&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21861153%26dopt%3DAbstract Authors: Jiang X, Xu X, Huo Y, Wu Y, Zhu X, Zhang X, Wu M Abstract A deep-sea sediment metagenomic library was constructed and screened for lipolytic enzymes by activity-based approach. Nine novel lipolytic enzymes were identified, and the amino acid sequences shared 56% to 84% identity to other lipolytic enzymes in the database. Phylogenetic analysis showed that these enzymes belonged to family IV lipolytic enzymes. One of the lipolytic enzymes, Est6, was successfully cloned and expressed in Escherichia coli Rosetta in a soluble form. The recombinant protein was purified by Ni-nitrilotriacetic affinity chromatography column and characterized using p-nitrophenyl esters with various chain lengths. The est6 gene consisted of 909 bp that encoded 302 amino acid residues. Est6 was most... Archives of Microbiology journals http://www.medworm.com/rss/comments.php?id=5157190 Mon, 22 Aug 2011 23:00:00 +0100 5157190 http://www.medworm.com/index.php?rid=5157193&cid=s_37326_77_f&fid=37326&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21858648%26dopt%3DAbstract Authors: Boden R, Cleland D, Green PN, Katayama Y, Uchino Y, Murrell JC, Kelly DP Abstract The 16S rRNA gene sequences of 12 strains of Thiobacillus thioparus held by different culture collections have been compared. A definitive sequence for the reference type strain (Starkey; ATCC 8158(T)) was obtained. The sequences for four examples of the Starkey type strain were essentially identical, confirming their sustained identity after passage through different laboratories. One strain (NCIMB 8454) was reassigned as a strain of Halothiobacillus neapolitanus, and a second (NCIMB 8349) was a species of Thermithiobacillus. These two strains have been renamed in their catalog by the National Collection of Industrial and Marine Bacteria. The 16S rRNA gene sequence of the type strain of Halo... Archives of Microbiology journals http://www.medworm.com/rss/comments.php?id=5157193 Sat, 20 Aug 2011 23:00:00 +0100 5157193 http://www.medworm.com/index.php?rid=5157192&cid=s_37326_77_f&fid=37326&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21858649%26dopt%3DAbstract Authors: Staudt AK, Wolfe LG, Shrout JD Abstract Rhizobium tropici, a legume-symbiont soil bacterium, is known for its copious production of exopolysaccharide (EPS). Many aspects of this organism's growth and EPS production, however, remain uncharacterized, including the influence of environment and culturing conditions upon EPS. Here, we demonstrate that R. tropici EPS chemical composition and yield differ when grown with different substrates in a defined minimal medium in batch culture. Exopolysaccharide was quantified from R. tropici grown using arabinose, glucose, sucrose, mannitol, fructose, or glutamate as a sole carbon source. All tested substrates produced plenteous amounts of exopolysaccharide material. Variations in pH and carbon-to-nitrogen (C/N) ratio also resulted in a... Archives of Microbiology journals http://www.medworm.com/rss/comments.php?id=5157192 Sat, 20 Aug 2011 23:00:00 +0100 5157192 http://www.medworm.com/index.php?rid=5157194&cid=s_37326_77_f&fid=37326&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21858429%26dopt%3DAbstract Authors: Benitez LB, Velho RV, de Souza da Motta A, Segalin J, Brandelli A Abstract Bacillus amyloliquefaciens LBM 5006 produces an antimicrobial factor active against Paenibacillus larvae, a major honeybee pathogen. The antagonistic effect and the mode of action of the antimicrobial factor were investigated. The antibacterial activity was produced starting at mid-logarithmic growth phase, reaching its maximum during the stationary phase. Exposure of cell suspensions of P. larvae to this antimicrobial resulted in loss of cell viability and reduction in optical density associated with cell lysis. Scanning electron microscopy showed damaged cell envelope and loss of protoplasmic material. The antimicrobial factor was stable for up to 80°C, but it was sensitive to proteinase K and tr... Archives of Microbiology journals http://www.medworm.com/rss/comments.php?id=5157194 Fri, 19 Aug 2011 23:00:00 +0100 5157194 http://www.medworm.com/index.php?rid=5098340&cid=s_37326_77_f&fid=37326&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21814817%26dopt%3DAbstract Authors: Smits TH, Duffy B Genomics has clarified the biosynthetic pathway for desferrioxamine E critical for iron acquisition in the enterobacterial fire blight pathogen Erwinia amylovora. Evidence for each of the individual steps and the role of desferrioxamine E biosynthesis in pathogen virulence and cell protection from host defenses is presented. Using comparative genomics, it can be concluded that desferrioxamine biosynthesis is ancestral within the genera Erwinia and Pantoea. PMID: 21814817 [PubMed - as supplied by publisher] (Source: Archives of Microbiology) Archives of Microbiology journals http://www.medworm.com/rss/comments.php?id=5098340 Wed, 03 Aug 2011 23:00:00 +0100 5098340 http://www.medworm.com/index.php?rid=5098341&cid=s_37326_77_f&fid=37326&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21805371%26dopt%3DAbstract Authors: Rücker O, Köhler A, Behammer B, Sichau K, Overmann J Whole cells of the purple sulfur bacterium strain 970 exhibit an unusual absorption peak at 963 nm. Its closest relatives, Thiorhodovibrio (Trv.) winogradskyi DSM6702(T) and strain 06511 display a bacteriochlorophyll (BChl) a absorption peak at 867 nm that is characteristic for most light-harvesting complexes 1 (LHC1) of proteobacteria. The puf operons encoding the LHC1 and reaction center proteins were amplified, cloned, and sequenced, and for the Trv. winogradskyi, strains show the common pufBALMC gene arrangement, whereas strain 970 contains a second pufBA copy downstream of pufC. Only pufB ( 1 ) A ( 1 ) is transcribed, and the corresponding mRNA fragment had an increased stability. Alignments of the deduced protein s... Archives of Microbiology journals http://www.medworm.com/rss/comments.php?id=5098341 Sat, 30 Jul 2011 23:00:00 +0100 5098341 http://www.medworm.com/index.php?rid=5098342&cid=s_37326_77_f&fid=37326&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21800148%26dopt%3DAbstract Authors: Romanenko LA, Tanaka N, Svetashev VI, Kalinovskaya NI The taxonomic study of two Gram-negative, aerobic, non-pigmented bacteria KMM 9010(T) and KMM 9023(T) isolated from a sandy sediment sample collected from the Sea of Japan seashore was performed. On the basis of the nearly complete 16S rRNA gene sequences, strains KMM 9010(T) and KMM 9023(T) clustered with the Roseobacter lineage (class Alphaproteobacteria) forming a distinct phylogenetic line adjacent to the genus Donghicola. Novel strains shared the highest sequence similarity of 96.4% to each other and lower than 96.1% similarities to other validly named genera of the class Alphaproteobacteria. In both strains, ubiquinone Q-10 was found to be the major respiratory quinone; phosphatidylcholine, phosphatidylglycerol, dipho... Archives of Microbiology journals http://www.medworm.com/rss/comments.php?id=5098342 Thu, 28 Jul 2011 23:00:00 +0100 5098342 http://www.medworm.com/index.php?rid=5098343&cid=s_37326_77_f&fid=37326&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21779790%26dopt%3DAbstract Authors: Gtari M, Ghodhbane-Gtari F, Nouioui I, Beauchemin N, Tisa LS It was assumed for a long time that the ability to catalyze atmospheric nitrogen (diazotrophy) has a narrow distribution among actinobacteria being limited to the genus Frankia. Recently, the number of nitrogen fixation (nifH) genes identified in other non-Frankia actinobacteria has dramatically increased and has opened investigation on the origin and emergence of diazotrophy among actinobacteria. During the last decade, Mycobacterium flavum, Corynebacterium autotrophicum and a fluorescent Arthrobacter sp. have been reported to have nitrogenase activity, but these studies have not been further verified. Additional reports of nitrogen fixation by Agromyces, Microbacterium, Corynebacterium and Micromonospora isolated f... Archives of Microbiology journals http://www.medworm.com/rss/comments.php?id=5098343 Wed, 20 Jul 2011 23:00:00 +0100 5098343 http://www.medworm.com/index.php?rid=5051845&cid=s_37326_77_f&fid=37326&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21773799%26dopt%3DAbstract Authors: Huang Y, Benson DR Filamentous actinobacteria from the genus Frankia grow by hyphal tip extension and branching. The growth kinetics and branching pattern of Frankia are not well studied, especially at the early stages of mycelial development. Here, we compare the growth of Frankia sp. strain CcI3 in liquid cultures with and without proteose peptone #3 (PP3) using time-lapse photomicrography and image analysis. Individual hyphae showed a pseudolinear increase in length at early stages of development, whereas at the mycelial level, the aggregate length of hyphae described an exponential rate before slowing. Growth based on optical density or microscopic observations was similar in medium with or without PP3. However, PP3 altered the pattern of mycelial development by increasing... Archives of Microbiology journals http://www.medworm.com/rss/comments.php?id=5051845 Tue, 19 Jul 2011 23:00:00 +0100 5051845 http://www.medworm.com/index.php?rid=5051844&cid=s_37326_77_f&fid=37326&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21773800%26dopt%3DAbstract Authors: Sen A, Thakur S, Bothra AK, Sur S, Tisa LS The TTA codon, one of the six available codons for the amino acid leucine, is the rarest codon among the high GC genomes of Actinobacteria including Frankia. This codon has been implicated in various regulatory mechanisms involving secondary metabolism and morphological development. TTA-mediated gene regulation is well documented in Streptomyces coelicolor, but that role has not been investigated in other Actinobacteria including Frankia. Among the various Actinomycetes with a GC content of more than 70%, Frankia genomes had the highest percentages of TTA-containing genes ranging from 5.2 to 10.68% of the genome. In contrast, TTA-bearing genes comprised 1.7, 3.4 and 4.1% of the Streptomyces coelicolor, S. avermitilis and Nocardia farc... Archives of Microbiology journals http://www.medworm.com/rss/comments.php?id=5051844 Tue, 19 Jul 2011 23:00:00 +0100 5051844 http://www.medworm.com/index.php?rid=5051846&cid=s_37326_77_f&fid=37326&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21769644%26dopt%3DAbstract Authors: Oh CJ, Kim HB, Kim J, Kim WJ, Lee H, An CS The nucleotide sequence of a 20.5-kb genomic region harboring nif genes was determined and analyzed. The fragment was obtained from Frankia sp. EuIK1 strain, an indigenous symbiont of Elaeagnus umbellata. A total of 20 ORFs including 12 nif genes were identified and subjected to comparative analysis with the genome sequences of 3 Frankia strains representing diverse host plant specificities. The nucleotide and deduced amino acid sequences showed highest levels of identity with orthologous genes from an Elaeagnus-infecting strain. The gene organization patterns around the nif gene clusters were well conserved among all 4 Frankia strains. However, characteristic features appeared in the location of the nifV gene for each Frankia strain,... Archives of Microbiology journals http://www.medworm.com/rss/comments.php?id=5051846 Sat, 16 Jul 2011 23:00:00 +0100 5051846 http://www.medworm.com/index.php?rid=5051847&cid=s_37326_77_f&fid=37326&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21766186%26dopt%3DAbstract Authors: Chen WM, Sheu FS, Sheu SY A bacterial strain designated antisso-27(T), previously isolated from saltpan in Taiwan while screening for bacteria for algicidal activity, was characterized using the polyphasic taxonomic approach. Strain antisso-27(T) was Gram-negative, aerobic, brownish yellow colored, rod-shaped, non-flagellated and non-gliding. Phylogenetic analyses based on 16S rRNA gene sequences showed that strain antisso-27(T) belonged to the genus Aquimarina within the family Flavobacteriaceae with relatively low sequence similarities of 94.0-96.6% to other valid Aquimarina spp. It contained iso-C(17:0) 3-OH, iso-C(15:0), iso-C(16:0), iso-C(15:1) and iso-C(15:0) 3-OH as the main fatty acids and contained a menaquinone with six isoprene units (MK-6) as the major isoprenoid q... Archives of Microbiology journals http://www.medworm.com/rss/comments.php?id=5051847 Fri, 15 Jul 2011 23:00:00 +0100 5051847 http://www.medworm.com/index.php?rid=5051848&cid=s_37326_77_f&fid=37326&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21761170%26dopt%3DAbstract Authors: Margaret-Oliver I, Lei W, Parada M, Rodríguez-Carvajal MA, Crespo-Rivas JC, Hidalgo A, Gil-Serrano A, Moreno J, Rodríguez-Navarro DN, Buendía-Clavería A, Ollero J, Ruiz-Sainz JE, Vinardell JM The Sinorhizobium fredii HH103 rkp-1 region, which is involved in capsular polysaccharide (KPS) biosynthesis, is constituted by the rkpU, rkpAGHIJ, and kpsF3 genes. Two mutants in this region affecting the rkpA (SVQ536) and rkpI (SVQ538) genes were constructed. Polyacrylamide gel electrophoresis and (1)H-NMR analyses did not detect KPS in these mutants. RT-PCR experiments indicated that, most probably, the rkpAGHI genes are cotranscribed. Glycine max cultivars (cvs.) Williams and Peking inoculated with mutants SVQ536 and SVQ538 showed reduced nodulation and symptoms of nitrogen starva... Archives of Microbiology journals http://www.medworm.com/rss/comments.php?id=5051848 Thu, 14 Jul 2011 23:00:00 +0100 5051848 http://www.medworm.com/index.php?rid=5051850&cid=s_37326_77_f&fid=37326&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21735228%26dopt%3DAbstract Authors: Kliefoth M, Langer JD, Matschiavelli N, Oelgeschläger E, Rother M When Methanosarcina acetivorans grows on carbon monoxide (CO), it synthesizes high levels of a protein, MA4079, homologous to aldehyde dehydrogenases. To investigate the role of MA4079 in M. acetivorans, mutants lacking the encoding gene were generated and phenotypically analyzed. Loss of MA4079 had no effect on methylotrophic growth but led to complete abrogation of methylotrophic growth in the presence of even small amounts of CO, which indicated the mutant's inability to acclimate to the presence of this toxic gas. Prolonged incubation with CO allowed the isolation of a strain in which the effect of MA4079 deletion is suppressed. The strain, designated Mu3, tolerated the presence of high CO partial pressures... Archives of Microbiology journals http://www.medworm.com/rss/comments.php?id=5051850 Wed, 06 Jul 2011 23:00:00 +0100 5051850 http://www.medworm.com/index.php?rid=5051849&cid=s_37326_77_f&fid=37326&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21735229%26dopt%3DAbstract Authors: Martins A, Vasconcelos V Toxic cyanobacteria blooms are increasingly frequent and object of greater concern due to its ecological and health impacts. One important lack in the toxic cyanobacteria research field is to understand which parameters influence most and how they operate to regulate the overall levels of cyanotoxins in a body of water. MC concentration is believed to be influenced by changes in several seasonal environmental factors that influence the succession of toxic cyanobacteria. In the last years, qPCR (quantitative polymerase chain reaction) has been applied to determine the seasonal and temporal shifts in the proportions of MC-producing and non-MC-producing subpopulations by quantifying both mcy genotypes and total population numbers. We discuss the most prom... Archives of Microbiology journals http://www.medworm.com/rss/comments.php?id=5051849 Wed, 06 Jul 2011 23:00:00 +0100 5051849 http://www.medworm.com/index.php?rid=5006592&cid=s_37326_77_f&fid=37326&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21717143%26dopt%3DAbstract Authors: Pinske C, Krüger S, Soboh B, Ihling C, Kuhns M, Braussemann M, Jaroschinsky M, Sauer C, Sargent F, Sinz A, Sawers RG Escherichia coli can both oxidize hydrogen and reduce protons. These activities involve three distinct [NiFe]-hydrogenases, termed Hyd-1, Hyd-2, and Hyd-3, each minimally comprising heterodimers of a large subunit, containing the [NiFe] active site, and a small subunit, bearing iron-sulfur clusters. Dihydrogen-oxidizing activity can be determined using redox dyes like benzyl viologen (BV); however, it is unclear whether electron transfer to BV occurs directly at the active site, or via an iron-sulfur center in the small subunit. Plasmids encoding Strep-tagged derivatives of the large subunits of the three E. coli [NiFe]-hydrogenases restored activity of the res... Archives of Microbiology journals http://www.medworm.com/rss/comments.php?id=5006592 Wed, 29 Jun 2011 23:00:00 +0100 5006592 http://www.medworm.com/index.php?rid=4959649&cid=s_37326_77_f&fid=37326&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21691775%26dopt%3DAbstract Authors: Liu H, Yin H, Dai Y, Dai Z, Liu Y, Li Q, Jiang H, Liu X Although the synergetic interactions between chemolithoautotroph Acidithiobacillus ferrooxidans and heterotroph Acidiphilium acidophilum have drawn a share of attention, the influence of Aph. acidophilum on growth and metabolic functions of At. ferrooxidans is still unknown on transcriptional level. To assess this influence, a co-culture composed by At. ferrooxidans and Aph. acidophilum was successfully acclimated in this study. Depending on the growth dynamics, At. ferrooxidans in co-culture had 2 days longer exponential phase and 5 times more cell number than that in pure culture. The ferrous iron concentration in culture medium and the expression of iron oxidation-related genes revealed that the energy acquisition of ... Archives of Microbiology journals http://www.medworm.com/rss/comments.php?id=4959649 Mon, 20 Jun 2011 23:00:00 +0100 4959649 http://www.medworm.com/index.php?rid=4959650&cid=s_37326_77_f&fid=37326&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21688029%26dopt%3DAbstract Authors: Oh EA, Chi WJ, Kim MS, Kang SS, Chun J, Hong SK Streptomyces coelicolor, the model species for morphologically complex actinomycete bacteria, has unique characteristics such as morphological and physiological differentiation, which are controlled by various factors and several protein kinases. From the whole genomic sequence of S. coelicolor A3(2), 44 putative serine/threonine (Ser/Thr) protein kinases were identified, and the pkaF gene was chosen as the best-conserved protein for typical Ser/Thr protein kinases. pkaF encodes a 667-amino acid protein with a predicted N-terminal Ser/Thr kinase domain and four repeated C-terminal penicillin-binding domains and Ser/Thr kinase-associated (PASTA) domains. Based on PCR, a pkaF gene was cloned and heterologously expressed. PkaF expre... Archives of Microbiology journals http://www.medworm.com/rss/comments.php?id=4959650 Fri, 17 Jun 2011 23:00:00 +0100 4959650 http://www.medworm.com/index.php?rid=4959651&cid=s_37326_77_f&fid=37326&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21667166%26dopt%3DAbstract Authors: Wassmann M, Moeller R, Reitz G, Rettberg P After 700 generations of a short-term evolution experiment with Bacillus subtilis 168, two strains were isolated, the UV-adapted strain MW01 and the UV-unexposed control strain DE69, and chosen for UV-C radiation resistance studies with respect to growth phase. The ancestral strain from the evolution experiment was used as reference for comparative purposes. Cells of the UV-adapted strain showed significant differences in their physiology (growth behavior, doubling time, cell density, and sporulation capacity) and were more resistant to UV in all monitored stages. These findings implicate the evolution to an increased UV radioresistance was not limited to a specific growth phase and led to reduced growth dynamics, compared with those ... Archives of Microbiology journals http://www.medworm.com/rss/comments.php?id=4959651 Fri, 10 Jun 2011 23:00:00 +0100 4959651 http://www.medworm.com/index.php?rid=4959652&cid=s_37326_77_f&fid=37326&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21655947%26dopt%3DAbstract In conclusion, we show that despite phenotypic diversity among clinical strains of S. enteritidis, the majority of strains are highly invasive in vitro and in vivo. PMID: 21655947 [PubMed - as supplied by publisher] (Source: Archives of Microbiology) Archives of Microbiology journals http://www.medworm.com/rss/comments.php?id=4959652 Tue, 07 Jun 2011 23:00:00 +0100 4959652 http://www.medworm.com/index.php?rid=4911917&cid=s_37326_77_f&fid=37326&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21638055%26dopt%3DAbstract In this study, we investigated the ability of several (hyper-) thermophilic Archaea and phylogenetically deep-branching thermophilic Bacteria to survive high fluences of monochromatic UV-C (254 nm) and high doses of ionizing radiation, respectively. Nine out of fourteen tested microorganisms showed a surprisingly high tolerance against ionizing radiation, and two species (Aquifex pyrophilus and Ignicoccus hospitalis) were even able to survive 20 kGy. Therefore, these species had a comparable survivability after exposure to ionizing radiation such as Deinococcus radiodurans. In contrast, there was nearly no difference in survival of the tested strains after exposure to UV-C under anoxic conditions. If the cells had been dried in advance of UV-C irradiation, they were more sensitive to UV-... Archives of Microbiology journals http://www.medworm.com/rss/comments.php?id=4911917 Thu, 02 Jun 2011 23:00:00 +0100 4911917 http://www.medworm.com/index.php?rid=4911918&cid=s_37326_77_f&fid=37326&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21617984%26dopt%3DAbstract Authors: Schroeder S, Ranchou-Peyruse A, Ranchou-Peyruse M, Spain JC Hydrogen-oxidising bacteria play a key ecological role in a variety of habitats including the rhizosphere and hot springs. To investigate the possibly of interspecies hydrogen exchange between cyanobacteria and hydrogen-oxidising bacteria, we developed a sensitive and reliable reverse-transcriptase qPCR assay for up-regulation of the hupS gene in the knallgas bacterium Alcaligenes hydrogenophilus DSM2625. The assay detected up-regulation of the gene at initial hydrogen concentrations as low as 0.12 μM. Expression of hupS also increased in the presence of hydrogen-producing cyanobacteria, both when Ah DSM2625 was directly added to a hydrogen-producing culture of the cyanobacteria, and when cultures were physically se... Archives of Microbiology journals http://www.medworm.com/rss/comments.php?id=4911918 Thu, 26 May 2011 23:00:00 +0100 4911918 http://www.medworm.com/index.php?rid=4911919&cid=s_37326_77_f&fid=37326&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21614527%26dopt%3DAbstract Authors: Ochrombel I, Becker M, Krämer R, Marin K Potassium accumulation is an essential aspect of bacterial response to diverse stress situations; consequently its uptake plays a pivotal role. Here, we show that the Gram-positive soil bacterium Corynebacterium glutamicum which is employed for the large-scale industrial production of amino acids requires potassium under conditions of ionic and non-ionic osmotic stress. Besides the accumulation of high concentrations of potassium contributing significantly to the osmotic potential of the cytoplasm, we demonstrate that glutamate is not the counter ion for potassium under these conditions. Interestingly, potassium is required for the activation of osmotic stress-dependent expression of the genes betP and proP. The Kup-type potassium tran... Archives of Microbiology journals http://www.medworm.com/rss/comments.php?id=4911919 Wed, 25 May 2011 23:00:00 +0100 4911919 http://www.medworm.com/index.php?rid=4911920&cid=s_37326_77_f&fid=37326&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21611773%26dopt%3DAbstract Authors: McLaughlin HP, Casey PG, Cotter J, Gahan CG, Hill C We investigated the ability of several strains of L. monocytogenes and Listeria innocua strains to survive in local soil samples in vitro. Survival of three L. monocytogenes strains, EGDe, CD83, and CD1038, and three L. innocua strains, CLIP, FH2117, FH2152, was monitored in soil samples by direct enumeration of colony-forming units on selective agar. The study did not demonstrate any species-specific difference in soil survival, and all Listeria strains exhibited a marked decline in numbers over time. Bioluminescence imaging approaches to detect lux-tagged strains in soil proved largely ineffective, most likely due to the reduced metabolic activity of strains in this environment. We investigated the influence of specific fac... Archives of Microbiology journals http://www.medworm.com/rss/comments.php?id=4911920 Tue, 24 May 2011 23:00:00 +0100 4911920 http://www.medworm.com/index.php?rid=4861902&cid=s_37326_77_f&fid=37326&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21594607%26dopt%3DAbstract Authors: Zhou Y, Xin Y, Sha S, Ma Y The UDP-N-acetylglucosamine (UDP-GlcNAc) is present as one of the glycosyl donors for disaccharide linker (D: -N-GlcNAc-L: -rhamnose) and the precursor of peptidoglycan in mycobacteria. The bifunctional enzyme GlmU involves in the last two sequential steps of UDP-GlcNAc synthetic pathway. Glucosamine-1-phosphate acetyltransferase catalyzes the formation of N-acetylglucosamine-1-phosphate (GlcNAc-1-P) from glucosamine-1-phosphate (GlcN-1-P) and acetyl coenzyme A (Acetyl CoA), and N-acetylglucosamine-1-phosphate uridyltransferase catalyzes the synthesis of UDP-GlcNAc from GlcNAc-1-P and UTP. The previous studies demonstrating the essentiality of GlmU to mycobacterial survival supported GlmU as a novel and potential target for TB drugs. In this work, tw... Archives of Microbiology journals http://www.medworm.com/rss/comments.php?id=4861902 Wed, 18 May 2011 23:00:00 +0100 4861902 http://www.medworm.com/index.php?rid=4861908&cid=s_37326_77_f&fid=37326&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21567174%26dopt%3DAbstract Authors: Sand M, de Berardinis V, Mingote A, Santos H, Göttig S, Müller V, Averhoff B Members of the genus Acinetobacter are well known for their metabolic versatility that allows them to adapt to different ecological niches. Here, we have addressed how the model strain Acinetobacter baylyi copes with different salinities and low water activities. A. baylyi tolerates up to 900 mM sodium salts and even higher concentrations of potassium chloride. Growth at high salinities was better in complex than in mineral medium and addition of glycine betaine stimulated growth at high salinities in mineral medium. Cells grown at high salinities took up glycine betaine from the medium. Uptake of glycine betaine was energy dependent and dependent on a salinity gradient across the membrane. Inspect... Archives of Microbiology journals http://www.medworm.com/rss/comments.php?id=4861908 Thu, 12 May 2011 23:00:00 +0100 4861908 http://www.medworm.com/index.php?rid=4861907&cid=s_37326_77_f&fid=37326&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21567175%26dopt%3DAbstract Authors: Lu H, Xia W, Chen H, Yin L, Zhao X, Xu G, Hua Y The extremely radioresistant bacterium Deinococcus radiodurans encodes a number of function-unknown genes, and some of them involve in the radioresistance. The radiation-inducible gene dr0171 has a recA-like expression pattern in the postirradiation recovery and was also supposed to encode a transcriptional regulator to contribute to the radioresistance. Here, we found that the EGFP-tagged DR0171 proteins gathered in the nucleoid regions after radiation. Further, we constructed a null mutant of dr0171 and found that the incapacitation of the dr0171 led to a significant decline in resistance to γ-rays, UV radiation, and hydrogen peroxide and delayed genomic DNA reconstruction after radiation, indicating that this gene is involved... Archives of Microbiology journals http://www.medworm.com/rss/comments.php?id=4861907 Thu, 12 May 2011 23:00:00 +0100 4861907 http://www.medworm.com/index.php?rid=4861906&cid=s_37326_77_f&fid=37326&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21567176%26dopt%3DAbstract Authors: Sharkey MA, Maher MA, Guyonvarch A, Engel PC The ldh gene of Corynebacterium glutamicum ATCC 13032 (gene symbol cg3219, encoding a 314 residue NAD(+)-dependent L: -(+)-lactate dehydrogenase, EC 1.1.1.27) was cloned into the expression vector pKK388-1 and over-expressed in an ldhA-null E. coli TG1 strain upon isopropyl-β-D-thiogalactopyranoside (IPTG) induction. The recombinant protein (referred to here as CgLDH) was purified by a combination of dye-ligand and ion-exchange chromatography. Though active in its absence, CgLDH activity is enhanced 17- to 20-fold in the presence of the allosteric activator D: -fructose-1,6-bisphosphate (Fru-1,6-P(2)). Contrary to a previous report, CgLDH has readily measurable reaction rates in both directions, with V (max) for the reduction of py... Archives of Microbiology journals http://www.medworm.com/rss/comments.php?id=4861906 Thu, 12 May 2011 23:00:00 +0100 4861906 http://www.medworm.com/index.php?rid=4861909&cid=s_37326_77_f&fid=37326&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21559929%26dopt%3DAbstract Authors: Reshamwala SM, Noronha SB Cra is a pleiotropic regulatory protein that controls carbon and energy flux in enteric bacteria. Recent studies have shown that Cra also regulates other cell processes and influences biofilm formation. The purpose of the present study was to investigate the role of Cra in biofilm formation in Escherichia coli. Congo red-binding studies suggested that curli biosynthesis is impaired in cra mutants. Microarray analysis of wild-type and mutant E. coli cultivated in conditions promoting biofilm formation revealed that the curli biosynthesis genes, csgBAC and csgDEFG, are poorly expressed in the mutant, suggesting that transcription of genes required for curli production is regulated by Cra. Four putative Cra-binding sites were identified in the curli inte... Archives of Microbiology journals http://www.medworm.com/rss/comments.php?id=4861909 Tue, 10 May 2011 23:00:00 +0100 4861909 http://www.medworm.com/index.php?rid=4804869&cid=s_37326_77_f&fid=37326&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21553045%26dopt%3DAbstract Authors: Salmerón-Santiago KG, Pardo JP, Flores-Herrera O, Mendoza-Hernández G, Miranda-Arango M, Guerra-Sánchez G Ustilago maydis is a fungal pathogen which is exposed during its life cycle to both abiotic and biotic stresses before and after the infection of maize. To cope with extreme environmental changes, microorganisms usually accumulate the disaccharide trehalose. We have investigated both the accumulation of trehalose and the activity of trehalase during the adaptation of U. maydis haploid cells to thermal, sorbitol, and NaCl stresses. Sorbitol and sodium chloride induced sustained accumulation of trehalose, while a transient increase was observed under heat stress. Sorbitol stressed cells showed higher trehalase activity compared with control cells and to those stressed by ... Archives of Microbiology journals http://www.medworm.com/rss/comments.php?id=4804869 Fri, 06 May 2011 23:00:00 +0100 4804869 http://www.medworm.com/index.php?rid=4804870&cid=s_37326_77_f&fid=37326&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21547566%26dopt%3DAbstract Authors: Mazzaferro L, Piñuel L, Minig M, Breccia JD PMID: 21547566 [PubMed - as supplied by publisher] (Source: Archives of Microbiology) Archives of Microbiology journals http://www.medworm.com/rss/comments.php?id=4804870 Thu, 05 May 2011 23:00:00 +0100 4804870 http://www.medworm.com/index.php?rid=4804871&cid=s_37326_77_f&fid=37326&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21541672%26dopt%3DAbstract Authors: Tseng CL, Chen JT, Lin JH, Huang WZ, Shaw GC The Bacillus subtilis cell wall hydrolase LytE is involved in cell wall turnover and cell separation during vegetative growth. lytE transcription is known to be driven by a YycF-activated SigA-dependent promoter. The cell wall regulator SigI is an alternative sigma factor that has been shown to be heat stress-inducible and to be essential for survival of B. subtilis at high temperature. However, none of the previously identified target genes of SigI contribute to heat resistance. We now demonstrate that lytE expression is heat-inducible and that heat induction of lytE expression is strongly dependent on SigI. We have also found that the lytE mutant shows the same growth defect at high temperature as the sigI mutant. Introducing an e... Archives of Microbiology journals http://www.medworm.com/rss/comments.php?id=4804871 Tue, 03 May 2011 23:00:00 +0100 4804871 http://www.medworm.com/index.php?rid=4804872&cid=s_37326_77_f&fid=37326&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21523387%26dopt%3DAbstract In this study, we analysed ACC deaminase genes (acdS) of bacterial endophytes colonizing field-grown potato plants. PCR analysis revealed the presence of two types of acdS genes, the dominant one showing high homology to an acdS gene derived from Pseudomonas fluorescens. Construction, functional screening and sequence analysis of metagenomic libraries revealed clones containing the acdS gene identified in the PCR library. Sequence analysis of one metagenomic clone identified the entire acdS operon of an uncultivated endophyte and revealed that the acdS gene is coupled upstream with an acdR transcriptional regulator gene as previously found in P. putida strain UW4 (Grichko and Glick 2000). However, in-silico analysis of 195 fully sequenced, acdS-containing bacterial genomes revealed that th... Archives of Microbiology journals http://www.medworm.com/rss/comments.php?id=4804872 Tue, 26 Apr 2011 23:00:00 +0100 4804872 http://www.medworm.com/index.php?rid=4804874&cid=s_37326_77_f&fid=37326&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21519853%26dopt%3DAbstract Authors: Luo D, Yang Y, Guo J, Zhang J, Guo Z, Liu S, Tian S 14-3-3 proteins are conserved regulatory proteins present in all eukaryotic cells that control numerous cellular activities via targeted protein interactions. To elucidate the interaction between P14-3-3 from Physarum polycephalum and actin in living cells, PCR and DNA recombination were used to generate various P14-3-3 and actin constructs. Yeast two-hybrid assay and FRET were employed to characterize the interaction between P14-3-3 and actin. The two-hybrid assay indicated that P14-3-3 N-terminal 76-108 amino acids and the C-terminal 207-216 amino acids played an important role in mediating interactions with actin, and the actin N-terminal 1-54 amino acids and the C-terminal 326-376 amino acids are also crucial in the inter... Archives of Microbiology journals http://www.medworm.com/rss/comments.php?id=4804874 Mon, 25 Apr 2011 23:00:00 +0100 4804874 http://www.medworm.com/index.php?rid=4804873&cid=s_37326_77_f&fid=37326&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21519854%26dopt%3DAbstract Authors: Patrauchan MA, Parnell JJ, McLeod MP, Florizone C, Tiedje JM, Eltis LD The phenylacetyl-CoA (Paa) catabolic pathway and genome-wide gene expression responses to phenylacetate catabolism were studied in the polychlorinated biphenyl (PCB)-degrading strain Burkholderia xenovorans LB400. Microarray and RT-qPCR analyses identified three non-contiguous chromosomal clusters of genes that are predicted to encode a complete Paa pathway that were induced up to 40-fold during growth of LB400 on phenylacetate: paaGHIJKR, paaANEBDF, and paaC. Comparison of the available genome sequences revealed that this organization is unique to Burkholderiaceae. Parallel proteomic studies identified 7 of the 14 predicted Paa proteins, most of which were detected only in phenylacetate-grown cells, but no... Archives of Microbiology journals http://www.medworm.com/rss/comments.php?id=4804873 Mon, 25 Apr 2011 23:00:00 +0100 4804873 http://www.medworm.com/index.php?rid=4804875&cid=s_37326_77_f&fid=37326&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21484295%26dopt%3DAbstract In this study, homology modeling of S. meliloti Hfq protein and cross-complementation experiments of S. meliloti and Escherichia coli mutants indicates that hfq ( Sm ) encodes an RNA chaperone that can be functionally exchanged by its homolog from E. coli. A transcriptional and translational analysis of S. meliloti hfq expression by means of lacZ reporter fusions strongly suggests that the S. meliloti Hfq protein autocontrols its expression at the translational level, a phenomenon that was evident in the natural host S. meliloti as well as in the heterologous host E. coli. PMID: 21484295 [PubMed - as supplied by publisher] (Source: Archives of Microbiology) Archives of Microbiology journals http://www.medworm.com/rss/comments.php?id=4804875 Mon, 11 Apr 2011 23:00:00 +0100 4804875 http://www.medworm.com/index.php?rid=4698924&cid=s_37326_77_f&fid=37326&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21479918%26dopt%3DAbstract Authors: Geszvain K, Yamaguchi A, Maybee J, Tebo BM Bacterially mediated manganese(II) oxidation greatly affects the biogeochemical cycling of Mn and other elements. One species of bacteria that are capable of Mn(II) oxidation is the gamma-proteobacterium Pseudomonas putida GB-1. In this organism, Mn(II) oxidation begins in stationary phase on the outer surface of the cell, forming a layer of insoluble Mn(III,IV) oxides. A random transposon mutagenesis screen isolated 12 mutant strains of P. putida GB-1 that exhibited increased Mn(II) oxidation on solid media relative to wild type. In 8 out of the 12 strains, the transposon had inserted into a putative flagellar gene. Those 8 strains each had motility defects, thus the disrupted genes are part of the P. putida GB-1 flagellar regulon. T... Archives of Microbiology journals http://www.medworm.com/rss/comments.php?id=4698924 Sun, 10 Apr 2011 23:00:00 +0100 4698924 http://www.medworm.com/index.php?rid=4698925&cid=s_37326_77_f&fid=37326&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21479808%26dopt%3DAbstract This study presents a genetic characterization of four C. raciborskii strains isolated from the Bir M'cherga Tunisian reservoir. The toxicity assessment was investigated via molecular biology tools, which suggested that all the isolated strains were not producing cylindrospermopsin, saxitoxin, or microcystin. This result was further confirmed by HPLC and MALDI-TOF analyses. However, we report for the first time in C. raciborskii the presence of mcyA and mcyE, two segments of the microcystin synthetase mcy cluster. All the strains were identified taxonomically based on the 16S rRNA sequences, and their phylogenetic relationships were assessed using the rpoC1 region. Tunisian strains formed a distinct clade separated from the other African strains. PMID: 21479808 [PubMed - as supplied by... Archives of Microbiology journals http://www.medworm.com/rss/comments.php?id=4698925 Sat, 09 Apr 2011 23:00:00 +0100 4698925 http://www.medworm.com/index.php?rid=4698927&cid=s_37326_77_f&fid=37326&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21479530%26dopt%3DAbstract Authors: Barnett JP, Lawrence J, Mendel S, Robinson C In the Tat protein export pathway of Gram-negative bacteria, TatA and TatB are homologous proteins that carry out distinct and essential functions in separate sub-complexes. In contrast, Gram-positive Tat systems usually lack TatB and the TatA protein is bifunctional. We have used a mutagenesis approach to delineate TatA/B-type domains in the bifunctional TatAd protein from Bacillus subtilis. This involved expression of mutated TatAd variants in Escherichia coli and tests to determine whether the variants could function as TatA or TatB by complementing E. coli tatA and/or tatB mutants. We show that mutations in the C-terminal half of the transmembrane span and the subsequent FGP 'hinge' motif are critical for TatAd function with its... Archives of Microbiology journals http://www.medworm.com/rss/comments.php?id=4698927 Fri, 08 Apr 2011 23:00:00 +0100 4698927 http://www.medworm.com/index.php?rid=4698926&cid=s_37326_77_f&fid=37326&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21479531%26dopt%3DAbstract Authors: Csotonyi JT, Stackebrandt E, Swiderski J, Schumann P, Yurkov V A strain EG19(T) of aerobic bacteria able to form pleomorphic cells was isolated from a brine spring runoff stream in the west central region of the province of Manitoba, Canada. The pale pinkish purple strain contained bacteriochlorophyll a incorporated into light-harvesting I and reaction center complexes. Its inability to grow under anaerobic illuminated conditions prompted designation as a member of the functional group known as aerobic anoxygenic phototrophic bacteria. Phylogenetic analysis of the 16S rRNA gene sequence revealed that it belonged to the Gammaproteobacteria, forming a distinct branch of phototrophs distantly related to most described aerobic anoxygenic phototrophs, quite marginally related (95.6... Archives of Microbiology journals http://www.medworm.com/rss/comments.php?id=4698926 Fri, 08 Apr 2011 23:00:00 +0100 4698926 http://www.medworm.com/index.php?rid=4698929&cid=s_37326_77_f&fid=37326&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21475984%26dopt%3DAbstract Authors: Sakiyama T, Araie H, Suzuki I, Shiraiwa Y A glucose-tolerant strain of the cyanobacterium Synechocystis sp. PCC 6803, generally referred to as wild type, produces a hemolysin-like protein (HLP) located on the cell surface. To analyze the function of HLP, we constructed a mutant in which the hlp gene was disrupted. The growth rate of the mutant was reduced when the cells were stressed by treatment with CuSO(4), CdCl(2), ZnCl(2), ampicillin, kanamycin, or sorbitol in liquid medium, suggesting that HLP may increase cellular resistance to the inhibitory effects of these compounds. Uptake assays with (109)Cd(2+) using the silicone-oil layer centrifugation technique revealed that both wild type and mutant cells were labeled with (109)Cd(2+) within 1 min. Although the total radioact... Archives of Microbiology journals http://www.medworm.com/rss/comments.php?id=4698929 Thu, 07 Apr 2011 23:00:00 +0100 4698929 http://www.medworm.com/index.php?rid=4698937&cid=s_37326_77_f&fid=37326&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21448720%26dopt%3DAbstract Authors: Shrivastava R, Basu A, Phale PS Pseudomonas putida CSV86 utilizes benzyl alcohol via catechol and methylnaphthalenes through detoxification pathway via hydroxymethylnaphthalenes and naphthaldehydes. Based on metabolic studies, benzyl alcohol dehydrogenase (BADH) and benzaldehyde dehydrogenase (BZDH) were hypothesized to be involved in the detoxification pathway. BADH and BZDH were purified to apparent homogeneity and were (1) homodimers with subunit molecular mass of 38 and 57 kDa, respectively, (2) NAD(+) dependent, (3) broad substrate specific accepting mono- and di-aromatic alcohols and aldehydes but not aliphatic compounds, and (4) BADH contained iron and magnesium, while BZDH contained magnesium. BADH in the forward reaction converted alcohol to aldehyde and required NAD... Archives of Microbiology journals http://www.medworm.com/rss/comments.php?id=4698937 Tue, 29 Mar 2011 23:00:00 +0100 4698937 http://www.medworm.com/index.php?rid=4698944&cid=s_37326_77_f&fid=37326&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21445557%26dopt%3DAbstract Authors: Lopez BR, Bashan Y, Bacilio M The small cactus Mammillaria fraileana is a pioneer rock-colonizing plant harboring endophytic bacteria with the potential for nitrogen fixation and rock weathering (phosphate solubilization and rock degradation). In seeds, only a combination of culture-independent methods, such as fluorescence in situ hybridization, scanning electron microscopy, and fluorescence vital staining, detected significant amounts of non-culturable, but living, endophytic bacteria distributed underneath the membrane covering the embryo, in the undifferentiated tissue of the embryo, and in the vascular tissue. Large populations of culturable endophytic bacteria were detected in stems and roots of wild plants colonizing rocks in the southern Sonoran Desert, but not in seed... Archives of Microbiology journals http://www.medworm.com/rss/comments.php?id=4698944 Mon, 28 Mar 2011 23:00:00 +0100 4698944 http://www.medworm.com/index.php?rid=4698943&cid=s_37326_77_f&fid=37326&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21445558%26dopt%3DAbstract This study forms the first detailed report on phosphate solubilization by the PPFMs. PMID: 21445558 [PubMed - as supplied by publisher] (Source: Archives of Microbiology) Archives of Microbiology journals http://www.medworm.com/rss/comments.php?id=4698943 Mon, 28 Mar 2011 23:00:00 +0100 4698943 http://www.medworm.com/index.php?rid=4698953&cid=s_37326_77_f&fid=37326&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21442317%26dopt%3DAbstract Authors: Cardona F, Orozco H, Friant S, Aranda A, Del Olmo ML SPI1 is a gene whose expression responds to many environmental stimuli, including entry into stationary phase. We have performed a screening to identify genes that activate SPI1 promoter when overexpressed. The phosphatidylinositol-4-phosphate 5-kinase gene MSS4 was identified as a positive activator of SPI1. Another SPI1 transcriptional regulator isolated was the flavodoxin-like gene YCP4. YCP4 and its homolog RFS1 regulate the expression of many genes during the late stages of growth. The double deletion mutant in YCP4 and its homolog RFS1 has an impact on gene expression related to metabolism by increasing the expression of genes involved in hexose transport and glycolysis, and decreasing expression of genes of amino acid... Archives of Microbiology journals http://www.medworm.com/rss/comments.php?id=4698953 Sun, 27 Mar 2011 00:00:00 +0100 4698953 http://www.medworm.com/index.php?rid=4698951&cid=s_37326_77_f&fid=37326&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21442319%26dopt%3DAbstract Authors: Mishra PK, Bisht SC, Ruwari P, Selvakumar G, Joshi GK, Bisht JK, Bhatt JC, Gupta HS Twelve psychrotolerant Pseudomonad strains were selected on the basis of various plant growth-promoting (PGP) activities at cold temperature (4°C). The effect of inoculation with Pseudomonad strains on cold alleviation and growth of wheat seedling at cold temperature (8°C) was investigated under greenhouse condition. Inoculation with Pseudomonad strains significantly enhanced root/shoot biomass and nutrients uptake as compared to non-bacterized control at 60 days of plant growth. Bacterization significantly improved the level of cellular metabolites like chlorophyll, anthocyanin, free proline, total phenolics, starch content, physiologically available iron, proteins, and amino acids that are... Archives of Microbiology journals http://www.medworm.com/rss/comments.php?id=4698951 Sun, 27 Mar 2011 00:00:00 +0100 4698951 http://www.medworm.com/index.php?rid=4698952&cid=s_37326_77_f&fid=37326&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21442318%26dopt%3DAbstract Authors: Zalatan F, Black P Studies evaluating the uptake of long-chain fatty acids in Caulobacter crescentus are consistent with a protein-mediated process. Using oleic acid (C18:1) as a substrate, fatty acid uptake was linear for up to 15 min. This process was saturable giving apparent V(max) and K(m) values of 374 pmol oleate transported/min/mg total protein and 61 μM oleate, respectively, consistent with the notion that one or more proteins are likely involved. The rates of fatty acid uptake in C. crescentus were comparable to those defined in Escherichia coli. Uncoupling the electron transport chain inhibited oleic acid uptake, indicating that like the long-chain fatty acid uptake systems defined in other gram-negative bacteria, this process is energy-dependent in C. crescentu... Archives of Microbiology journals http://www.medworm.com/rss/comments.php?id=4698952 Sat, 26 Mar 2011 00:00:00 +0100 4698952 http://www.medworm.com/index.php?rid=4698948&cid=s_37326_77_f&fid=37326&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21442320%26dopt%3DAbstract This study presents the isolation and characterization of phosphobacteria from Puna, northwestern Argentina and the ability to produce phosphate solubilization, alkaline phosphatase, siderophores, and indole acetic acid. The P-solubilizing activity was coincidental with a decrease in pH values of the tricalcium phosphate medium for all strains after 72 h of incubation. All the isolates showed the capacity to produce siderophores and indoles. Identification by 16S rDNA sequencing and phylogenetic analysis revealed that these strains belong to the genera Pantoea, Serratia, Enterobacter, and Pseudomonas. These isolates appear attractive for exploring their plant growth-promoting activity and potential field application. PMID: 21442320 [PubMed - as supplied by publisher] (Source: Archives... Archives of Microbiology journals http://www.medworm.com/rss/comments.php?id=4698948 Sat, 26 Mar 2011 00:00:00 +0100 4698948 http://www.medworm.com/index.php?rid=4642626&cid=s_37326_77_f&fid=37326&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21424691%26dopt%3DAbstract Authors: Shao Z, Gao J, Ding X, Wang J, Chiao J, Zhao G Nitrate assimilation has been well studied for Gram-negative bacteria but not so much in the Gram-positive actinomycetes up to date. In a rifamycin SV-producing actinomycete, Amycolatopsis mediterranei strain U32, nitrate not only can be used as a sole nitrogen source but also remarkably stimulates the antibiotic production along with regulating the related metabolic enzymes. A gene cluster of nasACKBDEF was cloned from a U32 genomic library by in situ hybridization screening with a heterogeneous nasB probe and confirmed later by whole genome sequence, corresponding to the protein coding genes of AMED_1121 to AMED_1127. These genes were co-transcribed as an operon, concomitantly repressed by ammonium while activated with supplemen... Archives of Microbiology journals http://www.medworm.com/rss/comments.php?id=4642626 Tue, 22 Mar 2011 00:00:00 +0100 4642626 http://www.medworm.com/index.php?rid=4642627&cid=s_37326_77_f&fid=37326&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21409355%26dopt%3DAbstract Authors: Slyemi D, Moinier D, Brochier-Armanet C, Bonnefoy V, Johnson DB A moderately acidophilic, facultative chemoautotrophic, As(III)-oxidizing Thiomonas sp. (strain 3As(T)) was previously shown, on the basis of comparative 16S rRNA gene sequences, to be closely related to both Tm. perometabolis DSM 18570(T) and Tm. intermedia DSM 18155(T). While it had shared many physiological traits with Tm. intermedia (T), a mean DNA-DNA hybridization value (DDHV) of 47.2% confirmed that strain 3As(T) was not a strain of Tm. intermedia, though the situation with regard to Tm. perometabolis (DDHV previously determined as 72%) was more ambiguous. A comparative physiological and chemotaxonomic study of strain 3As(T) and Tm. perometabolis (T) was therefore carried out, together with multilocus seque... Archives of Microbiology journals http://www.medworm.com/rss/comments.php?id=4642627 Wed, 16 Mar 2011 00:00:00 +0100 4642627 http://www.medworm.com/index.php?rid=4642628&cid=s_37326_77_f&fid=37326&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21400100%26dopt%3DAbstract Authors: Lakhal R, Auria R, Davidson S, Ollivier B, Durand MC, Dolla A, Hamdi M, Combet-Blanc Y A 2.3-L bioreactor was specially adapted to grow hyperthermophilic microorganisms under controlled conditions of temperature, pH, redox potential and dissolved O(2). Using this bioreactor regulated at 80°C and pH 7.0, we demonstrated that Thermotoga maritima recovered its growth despite being exposed to oxygen for a short time (30 min with a maximum concentration of 23 μM of dissolved oxygen). Under these conditions, we demonstrated that O(2) uptake rate, estimated at 73.6 μmoles O(2) min(-1) g proteins(-1) for dissolved oxygen, was optimal and constant, when dissolved oxygen was present in a range of 22-5 μM. Transcription analyses revealed that during short oxygen exposure, T. ma... Archives of Microbiology journals http://www.medworm.com/rss/comments.php?id=4642628 Sat, 12 Mar 2011 00:00:00 +0100 4642628 http://www.medworm.com/index.php?rid=4580779&cid=s_37326_77_f&fid=37326&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21387181%26dopt%3DAbstract Authors: Chen YR, Yang TY, Lei GS, Lin LJ, Chak KF The lysis protein of the colicinogenic operon is essential for colicin release and its main function is to activate the outer membrane phospholipase A (OMPLA) for the traverse of colicin across the cell envelope. However, little is known about the involvement of the lysis protein in the translocation of colicin across the inner membrane into the periplasm. The introduction of specific point mutations into the lipobox or sorting signal sequence of the lysE7 gene resulted in the production of various forms of lysis proteins. Our experimental results indicated that cells with wild-type mature LysE7 protein exhibited higher efficiency of colicin E7 translocation across the inner membrane into the periplasm than those with premature LysE7 p... Archives of Microbiology journals http://www.medworm.com/rss/comments.php?id=4580779 Thu, 10 Mar 2011 00:00:00 +0100 4580779 http://www.medworm.com/index.php?rid=4580781&cid=s_37326_77_f&fid=37326&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21374057%26dopt%3DAbstract Authors: Hung WL, Wade WG, Boden R, Kelly DP, Wood AP We show that bacteria with methylotrophic potential are ubiquitous in the human mouth microbiota. Numerous strains of Actinobacteria (Brevibacterium, Gordonia, Leifsonia, Microbacterium, Micrococcus, Rhodococcus) and Proteobacteria (Achromobacter, Klebsiella, Methylobacterium, Pseudomonas, Ralstonia) were isolated, and one strain of each of the eleven genera was studied in detail. These strains expressed enzymes associated with methylotrophic metabolism (methanol, methylamine, and formate dehydrogenases), and the assimilation of one-carbon compounds by the serine pathway (hydroxypyruvate reductase). Methylotrophic growth of the strains was enhanced by the addition of glass beads to cultures, suggesting that they may naturally occur ... Archives of Microbiology journals http://www.medworm.com/rss/comments.php?id=4580781 Sat, 05 Mar 2011 00:00:00 +0100 4580781 http://www.medworm.com/index.php?rid=4580780&cid=s_37326_77_f&fid=37326&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21374058%26dopt%3DAbstract Authors: Petersen J Whole genome sequences are present-day bonanzas for taxonomists. Comparative genomics provides a promising perspective to reveal the evolutionary relationship between organisms, but this strategy is not applicable for extrachromosomal elements due to their high recombination frequencies. Classification of plasmids is based on their compatibility, i.e., the ability to coexist within the same cell. Compatibility testing is a laborious experimental discipline of pairwise comparisons developed for a small set of replicons. Thus, novel approaches are urgently required to deal with the exponentially increasing amount of sequence data. In this minireview, a short overview about the functional role and distribution of plasmids as well as a summary of recent strategies to cl... Archives of Microbiology journals http://www.medworm.com/rss/comments.php?id=4580780 Sat, 05 Mar 2011 00:00:00 +0100 4580780 http://www.medworm.com/index.php?rid=4580782&cid=s_37326_77_f&fid=37326&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21369825%26dopt%3DAbstract Authors: Jovcic B, Venturi V, Topisirovic L, Kojic M Pseudomonas sp. strain ATCC19151 is a natural isolate from sewage with the ability to degrade detergents. Genes encoding potential choline sulfatase (betC), substrate-binding ABC transporter protein (betD), sulfate transporter (betE), and divergent putative transcriptional regulator (betR) were cloned and characterized from strain ATCC19151. In silico analysis revealed that (1) the BetC protein belongs to alkPPc superfamily and shares CXPXR sequence with the cysteine sulfatases of group I, (2) BetR belongs to the LysR family of transcriptional regulators, (3) BetD is part of the PBPb superfamily of periplasmic and membrane-associated proteins, and (4) BetE is a permease and contains STAS domain. Insertional mutagenesis and genetic co... Archives of Microbiology journals http://www.medworm.com/rss/comments.php?id=4580782 Thu, 03 Mar 2011 00:00:00 +0100 4580782 http://www.medworm.com/index.php?rid=4580788&cid=s_37326_77_f&fid=37326&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21359955%26dopt%3DAbstract This study offered the first systematic information about the diversity of microsymbionts nodulating Prosopis farcta in the arid regions of Tunisia. PMID: 21359955 [PubMed - as supplied by publisher] (Source: Archives of Microbiology) Archives of Microbiology journals http://www.medworm.com/rss/comments.php?id=4580788 Sun, 27 Feb 2011 00:00:00 +0100 4580788 http://www.medworm.com/index.php?rid=4580783&cid=s_37326_77_f&fid=37326&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21359956%26dopt%3DAbstract Authors: Pierce A, Gillette D, Jones PG Bacterial shape is controlled by peptidoglycan assembly along the lateral wall and at the septum site. In contrast to rods at 37°C, the wild-type strain formed coccobacilli at 12°C, indicating a prevailing shift toward septal peptidoglycan synthesis at low temperature. Escherichia coli cold shock protein CsdA is a DEAD-box RNA helicase with an extended variable region at the carboxyl terminus. The csdA null mutant formed elongated cells indicating that CsdA, directly or indirectly, effects an increase in septation and the resultant coccobacillus morphology. Lipoprotein NlpI is suggested for a role in cell division. The presence of a plasmid encoding CsdA or NlpI increased septation and coccobacillus morphology of the csdA null mutant cells. Pla... Archives of Microbiology journals http://www.medworm.com/rss/comments.php?id=4580783 Sun, 27 Feb 2011 00:00:00 +0100 4580783 http://www.medworm.com/index.php?rid=4580789&cid=s_37326_77_f&fid=37326&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21340506%26dopt%3DAbstract Authors: Frank CS, Langhammer P, Fuchs BM, Harder J A dimorphic life cycle has been described for the planctomycete Rhodopirellula baltica SH1(T), with juvenile motile, free-swimming cells and adult sessile, attached-living cells. However, attachment as a response to environmental factors was not investigated. We studied the response of R. baltica to nitrogen limitation. In batch cultures, ammonium limitation coincided with a dominance of free-swimming cells and a low number of aggregates. Flow cytometry revealed a quantitative shift with increasing ammonium availability, from single cells towards attached cells in large aggregates. During growth of R. baltica on glucose and ammonium in chemostats, an ammonium addition caused a macroscopic change of the growth behaviour, from homogeneo... Archives of Microbiology journals http://www.medworm.com/rss/comments.php?id=4580789 Tue, 22 Feb 2011 00:00:00 +0100 4580789 http://www.medworm.com/index.php?rid=4472447&cid=s_37326_77_f&fid=37326&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21298257%26dopt%3DAbstract Authors: Zhang W, Xu S, Li J, Shen X, Wang Y, Yuan Z The type VI secretion system (T6SS) is a novel secretion system found in many Gram-negative bacterial pathogens, which appears to be tightly regulated by different regulatory mechanisms. In the present study, we identified 4 T6SS clusters in Yersinia pseudotuberculosis and demonstrated that they were differentially thermoregulated. Among them, T6SS4 was preferentially expressed at 26°C, and its expression was growth phase dependent and subject to quorum sensing regulation. Both YpsI and YtbI AHL synthases contributed to the positive regulation of T6SS4, whereas YpsI synthase played the major role as T6SS4 expression was reduced strongly in the ypsI mutant strain but weakly in the ytbI mutant strain. Moreover, we provided evidence th... Archives of Microbiology journals http://www.medworm.com/rss/comments.php?id=4472447 Sat, 05 Feb 2011 00:00:00 +0100 4472447 http://www.medworm.com/index.php?rid=4472448&cid=s_37326_77_f&fid=37326&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21279628%26dopt%3DAbstract Authors: Han JH, Park JY, Yoo KS, Kang HW, Choi GW, Chung BW, Min J We have constructed recombinant Saccharomyces cerevisiae JH1 harboring a xylose reductase gene (xyl1) isolated from Pichia stipitis. However, JH1 still utilizes glucose more easily than xylose. Therefore, in this study, we characterized the effect of a glucose supplement on xylose utilization, the expression level of xylose reductase as a recombinant gene in JH1, and the expression levels of two hexose transporters (Hxt4 and Hxt7) due to co-fermentation of different concentrations of glucose and xylose. Co-fermentation using 20 g/l of glucose increased xylose consumption up to 11.7 g/l, which was 7.9-fold that of xylose fermentation without a glucose supplement. In addition, we found xyl1 mRNA levels dramatically inc... Archives of Microbiology journals http://www.medworm.com/rss/comments.php?id=4472448 Sun, 30 Jan 2011 00:00:00 +0100 4472448 http://www.medworm.com/index.php?rid=4472449&cid=s_37326_77_f&fid=37326&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21274516%26dopt%3DAbstract This study provides a labor and cost-saving new method for monitoring structural shifts of microbial communities. PMID: 21274516 [PubMed - as supplied by publisher] (Source: Archives of Microbiology) Archives of Microbiology journals http://www.medworm.com/rss/comments.php?id=4472449 Fri, 28 Jan 2011 00:00:00 +0100 4472449 http://www.medworm.com/index.php?rid=4405479&cid=s_37326_77_f&fid=37326&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21259000%26dopt%3DAbstract Authors: Courchesne WE, Vlasek C, Klukovich R, Coffee S Yeast suffers from a variety of environmental stresses, such as osmotic pressure and ethanol produced during fermentation. Since calcium ions are protective for high concentrations of ethanol, we investigated whether Ca(2+) flux occurs in response to ethanol stress. We find that exposure of yeast to ethanol induces a rise in the cytoplasmic concentration of Ca(2+). The response is enhanced in cells shifted to high-osmotic media containing proline, galactose, sorbitol, or mannitol. Suspension of cells in proline and galactose-containing media increases the Ca(2+) levels in the cytoplasm independent of ethanol exposure. The enhanced ability for ethanol to induce Ca(2+) flux after the hypertonic shift is transient, decreasing rapidly... Archives of Microbiology journals http://www.medworm.com/rss/comments.php?id=4405479 Sun, 23 Jan 2011 00:00:00 +0100 4405479 http://www.medworm.com/index.php?rid=4405480&cid=s_37326_77_f&fid=37326&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21249334%26dopt%3DAbstract Authors: Sleator RD The recent rapid expansion in the DNA and protein databases, arising from large-scale genomic and metagenomic sequence projects, has forced significant development in the field of phylogenetics: the study of the evolutionary relatedness of the planet's inhabitants. Advances in phylogenetic analysis have greatly transformed our view of the landscape of evolutionary biology, transcending the view of the tree of life that has shaped evolutionary theory since Darwinian times. Indeed, modern phylogenetic analysis no longer focuses on the restricted Darwinian-Mendelian model of vertical gene transfer, but must also consider the significant degree of lateral gene transfer, which connects and shapes almost all living things. Herein, I review the major tree-building methods,... Archives of Microbiology journals http://www.medworm.com/rss/comments.php?id=4405480 Thu, 20 Jan 2011 00:00:00 +0100 4405480 http://www.medworm.com/index.php?rid=4405481&cid=s_37326_77_f&fid=37326&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21243338%26dopt%3DAbstract Authors: Bird TH, Mackrell A The α-proteobacterium, Rhodospirillum centenum, has a complex life cycle that allows adaptation to different environments. Transitions between vegetative swim cell and swarmer cell types depend on whether the organism is growing in liquid surroundings or on a solid substrate. Moreover, starvation can induce vegetative cells to differentiate into quiescent cysts. This paper describes the results of our investigation into the role of a putative DNA-binding response regulator that is homologous to CtrA, the cell cycle regulator from Caulobacter crescentus. Deletion of ctrA from the R. centenum genome resulted in a viable strain with impaired swarming motility coupled with an increased tendency to form cysts. Conversely, overexpression of wild type CtrA or a p... Archives of Microbiology journals http://www.medworm.com/rss/comments.php?id=4405481 Tue, 18 Jan 2011 00:00:00 +0100 4405481 http://www.medworm.com/index.php?rid=4405485&cid=s_37326_77_f&fid=37326&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21234747%26dopt%3DAbstract Authors: Stackebrandt E PMID: 21234747 [PubMed - as supplied by publisher] (Source: Archives of Microbiology) Archives of Microbiology journals http://www.medworm.com/rss/comments.php?id=4405485 Sat, 15 Jan 2011 00:00:00 +0100 4405485 http://www.medworm.com/index.php?rid=4405484&cid=s_37326_77_f&fid=37326&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21234748%26dopt%3DAbstract Authors: Murata M, Uchida T, Yang Y, Lezhava A, Kinashi H We have comprehensively analyzed the linear chromosomes of Streptomyces griseus mutants constructed and kept in our laboratory. During this study, macrorestriction analysis of AseI and DraI fragments of mutant 402-2 suggested a large chromosomal inversion. The junctions of chromosomal inversion were cloned and sequenced and compared with the corresponding target sequences in the parent strain 2247. Consequently, a transposon-involved mechanism was revealed. Namely, a transposon originally located at the left target site was replicatively transposed to the right target site in an inverted direction, which generated a second copy and at the same time caused a 2.5-Mb chromosomal inversion. The involved transposon named TnSGR was gr... Archives of Microbiology journals http://www.medworm.com/rss/comments.php?id=4405484 Sat, 15 Jan 2011 00:00:00 +0100 4405484 http://www.medworm.com/index.php?rid=4405482&cid=s_37326_77_f&fid=37326&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21234750%26dopt%3DAbstract In this study, we describe an in silico analysis combining a stochastic data mining method, analysis of homologous gene distribution and the identification of features frequently associated with horizontally transferred genes to assess the proportion of the S. thermophilus genome that could originate from HGT. Our mining approach pointed out that about 17.7% of S. thermophilus genes (362 CDSs of 1,915) showed a composition bias; these genes were called 'atypical'. For 22% of them, their functional annotation strongly support their acquisition through HGT and consisted mainly in genes encoding mobile genetic recombinases, exopolysaccharide (EPS) biosynthesis enzymes or resistance mechanisms to bacteriophages. The distribution of the atypical genes in the Firmicutes phylum as well as in S. t... Archives of Microbiology journals http://www.medworm.com/rss/comments.php?id=4405482 Sat, 15 Jan 2011 00:00:00 +0100 4405482 http://www.medworm.com/index.php?rid=4405483&cid=s_37326_77_f&fid=37326&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21234749%26dopt%3DAbstract Authors: Tortora ML, Díaz-Ricci JC, Pedraza RO Anthracnose, caused by the fungus Colletotrichum acutatum is one of the most important diseases in strawberry crop. Due to environmental pollution and resistance produced by chemical fungicides, nowadays biological control is considered a good alternative for crop protection. Among biocontrol agents, there are plant growth-promoting bacteria, such as members of the genus Azospirillum. In this work, we demonstrate that under iron limiting conditions different strains of A. brasilense produce siderophores, exhibiting different yields and rates of production according to their origin. Chemical assays revealed that strains REC2 and REC3 secrete catechol type siderophores, including salicylic acid, detected by thin layer chromatography coupled... Archives of Microbiology journals http://www.medworm.com/rss/comments.php?id=4405483 Fri, 14 Jan 2011 00:00:00 +0100 4405483 http://www.medworm.com/index.php?rid=4338696&cid=s_37326_77_f&fid=37326&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21225241%26dopt%3DAbstract Authors: Hensley CT, Kamneva OK, Levy KM, Labahn SK, Africa LA, Wing HJ The Shigella flexneri outer membrane protease IcsP proteolytically cleaves the actin-based motility protein IcsA from the bacterial surface. The icsP gene is monocistronic and lies downstream of an unusually large intergenic region on the Shigella virulence plasmid. In silico analysis of this region predicts a second transcription start site 84 bp upstream of the first. Primer extension analyses and beta-galactosidase assays demonstrate that both transcription start sites are used. Both promoters are regulated by the Shigella virulence gene regulator VirB and both respond similarly to conditions known to influence Shigella virulence gene expression (iron concentration, pH, osmotic pressure, and phase of growth). T... Archives of Microbiology journals http://www.medworm.com/rss/comments.php?id=4338696 Wed, 12 Jan 2011 00:00:00 +0100 4338696 http://www.medworm.com/index.php?rid=4338698&cid=s_37326_77_f&fid=37326&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21221529%26dopt%3DAbstract Authors: Dohm N, Petri A, Schlander M, Schlott B, König H, Claus H Different strains of the genus Lactobacillus can be regularly isolated from must and wine samples. By various physiological activities, they can improve or reduce the wine quality. Lactobacillus hilgardii that is known to survive under harsh wine conditions is classified as a spoilage bacterium, e.g. due to the production of histamine. Many lactobacilli form an S-layer as the outermost cell wall component which has been found to facilitate the colonization of special ecological niches. A detailed understanding of the properties related to their S-layer proteins is necessary to improve the knowledge of the interactions between different bacterial cells and with the surrounding environments. The S-layer protein from the ... Archives of Microbiology journals http://www.medworm.com/rss/comments.php?id=4338698 Sun, 09 Jan 2011 00:00:00 +0100 4338698 http://www.medworm.com/index.php?rid=4338697&cid=s_37326_77_f&fid=37326&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21221530%26dopt%3DAbstract Authors: Bergmann FD, Selesi D, Meckenstock RU The sulfate-reducing highly enriched culture N47 is capable to anaerobically degrade naphthalene, 2-methylnaphthalene, and 2-naphthoic acid. A proteogenomic investigation was performed to elucidate the initial activation reaction of anaerobic naphthalene degradation. This lead to the identification of an alpha-subunit of a carboxylase protein that was two-fold up-regulated in naphthalene-grown cells compared to 2-methylnaphthalene-grown cells. The putative naphthalene carboxylase subunit showed 48% similarity to the anaerobic benzene carboxylase from an iron-reducing, benzene-degrading culture and 45% to alpha-subunit of phenylphosphate carboxylase of Aromatoleum aromaticum EbN1. A gene for the beta-subunit of putative naphthalene carboxyl... Archives of Microbiology journals http://www.medworm.com/rss/comments.php?id=4338697 Sat, 08 Jan 2011 00:00:00 +0100 4338697 http://www.medworm.com/index.php?rid=4338699&cid=s_37326_77_f&fid=37326&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21193902%26dopt%3DAbstract Authors: van Reenen CA, Dicks LM Probiotics are live cultures, usually lactic acid bacteria, which are ingested to promote a healthy gastrointestinal tract. These organisms require certain traits to survive and compete in this niche, but these traits may be transferred to other microbiota in the gastrointestinal tract (GIT). Similarly, virulence factors from pathogens may be acquired by probiotic strains. Bacteria have developed a plethora of methods to transfer genetic material between strains, species and genera. In this review, the possible factors that may be exchanged and the methods of exchange are discussed. PMID: 21193902 [PubMed - as supplied by publisher] (Source: Archives of Microbiology) Archives of Microbiology journals http://www.medworm.com/rss/comments.php?id=4338699 Fri, 31 Dec 2010 00:00:00 +0100 4338699 http://www.medworm.com/index.php?rid=4338703&cid=s_37326_77_f&fid=37326&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21184215%26dopt%3DAbstract Authors: Domman DB, Steven BT, Ward NL The Verrucomicrobia are a bacterial group of growing interest due to their environmental ubiquity as free-living and host-associated microbes. They also exhibit an unusual compartmentalized cell plan, shared with members of neighboring phyla that include the Planctomycete bacteria. However, Verrucomicrobia are currently difficult to study, due to a lack of available genetic tools that would permit robust testing of hypotheses formulated from ecological and genomic data. To our knowledge, there are no published studies describing the transformation of exogenous DNA into any members of the Verrucomicrobia (or the neighboring phylum containing Planctomycetes). Here, we present a procedure for the transformation of DNA into Verrucomicrobium spinosum D... Archives of Microbiology journals http://www.medworm.com/rss/comments.php?id=4338703 Fri, 24 Dec 2010 00:00:00 +0100 4338703 http://www.medworm.com/index.php?rid=4338702&cid=s_37326_77_f&fid=37326&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21184216%26dopt%3DAbstract Authors: Schweizer HP, Choi KH Unsaturated fatty acids (UFAs) play a pivotal role in maintaining a functional cellular membrane in response to changes in environmental factors. Unlike in other gram-negative bacteria, in Pseudomonas aeruginosa, UFA synthesis is governed by 2 pathways: (1) the anaerobic FabAB-mediated pathway and (2) the aerobic inducible DesA/DesB desaturase pathway. Although fatty acids are functional constituents of several known virulence factors, the roles of Pseudomonas aeruginosa fatty acid synthesis enzymes in virulence factor production and pathogenesis have not yet been examined. Previous studies have shown that the mycobacterial DesA1 and DesA3 proteins are required for full virulence. Therefore, we assessed the effect, if any, of mutations affecting the vario... Archives of Microbiology journals http://www.medworm.com/rss/comments.php?id=4338702 Fri, 24 Dec 2010 00:00:00 +0100 4338702 http://www.medworm.com/index.php?rid=4338701&cid=s_37326_77_f&fid=37326&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21184217%26dopt%3DAbstract Authors: Din N, Shoemaker CJ, Akin KL, Frederick C, Bird TH The photosynthetic bacterium, Rhodospirillum centenum, has a flexible life cycle that permits it to survive starvation as dormant cyst cells. Previous studies have identified some of the key regulators for encystment and demonstrated that the control of development is intricate. This complexity may arise from the need to integrate several environmental signals to mediate a switch from one mode of energy metabolism to another and to ensure that a transition to dormancy is initiated only when necessary. We searched for additional regulators of development by screening for encystment deficient strains after subjecting wild type R. centenum to mini-Tn5 mutagenesis. Analysis of "hypo-cyst" strains led to the identification of two g... Archives of Microbiology journals http://www.medworm.com/rss/comments.php?id=4338701 Fri, 24 Dec 2010 00:00:00 +0100 4338701 http://www.medworm.com/index.php?rid=4338700&cid=s_37326_77_f&fid=37326&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21184218%26dopt%3DAbstract Authors: Kumar S, Smith KP, Floyd JL, Varela MF A putative mannitol operon of the phosphoenolpyruvate phosphotransferase (PTS) type was cloned from Vibrio cholerae O395, and its activity was studied in Escherichia coli. The 3.9-kb operon comprising three genes is organized as mtlADR. Based on the sequence analysis, these were identified as genes encoding a putative mannitol-specific enzyme IICBA (EII(Mtl)) component (MtlA), a mannitol-1-phosphate dehydrogenase (MtlD), and a mannitol operon repressor (MtlR). The transport of [(3)H]mannitol by the cloned mannitol operon in E. coli was 13.8 ± 1.4 nmol/min/mg protein. The insertional inactivation of EII(Mtl) abolished mannitol and sorbitol transport in V. cholerae O395. Comparison of the mannitol utilization apparatus of V. cholerae wi... Archives of Microbiology journals http://www.medworm.com/rss/comments.php?id=4338700 Fri, 24 Dec 2010 00:00:00 +0100 4338700 http://www.medworm.com/index.php?rid=4277312&cid=s_37326_77_f&fid=37326&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21165603%26dopt%3DAbstract Authors: Warth L, Haug I, Altenbuchner J MrpA is the multimer resolution protein of the Streptomyces coelicolor A3(2) plasmid SCP2*. Previously, MrpA was found to significantly increase the stability of SCP2*-derived plasmids in Streptomyces lividans. The present report gives a functional characterization of MrpA. A sequence alignment revealed that MrpA shares highly conserved residues with members of the tyrosine recombinase family. After overexpression and Strep-tag purification, a DNase I footprint analysis and a gel mobility shift assay allowed for the identification of the 36-bp MrpA binding site mrpS. The mrpS site shows the configuration typical for tyrosine recombinases and contains two MrpA binding sites. The activity of MrpA was explored in vivo in E. coli cells and in vitro ... Archives of Microbiology journals http://www.medworm.com/rss/comments.php?id=4277312 Fri, 17 Dec 2010 00:00:00 +0100 4277312 http://www.medworm.com/index.php?rid=4251400&cid=s_37326_77_f&fid=37326&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21136040%26dopt%3DAbstract Authors: Miransari M Nitrogen (N) is among the most important macro-nutrients significantly affecting plant growth and yield production. Accordingly, N must be supplied adequately so that optimum amounts of yield are resulted. There are different ways of supplying N to the plant including the use of chemical and biological fertilization. The chemical properties of N make it very mobile, especially under humid conditions. Hence, N must not be overfertilized with respect to the economical and environmental points of view. N Biological fertilization includes the use of plant growth-promoting rhizobacteria (PGPR) including the N-fixing bacteria, rhizobium. There are also arbuscular mycorrhizal (AM) fungi in the soil, which are symbiotic to most terrestrial plants enhancing plant growth and... Archives of Microbiology journals http://www.medworm.com/rss/comments.php?id=4251400 Tue, 07 Dec 2010 00:00:00 +0100 4251400 http://www.medworm.com/index.php?rid=4251399&cid=s_37326_77_f&fid=37326&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21136041%26dopt%3DAbstract Authors: Goh K, Chua D, Beck B, McKee ML, Bhagwat AA Ability to survive the low pH of the human stomach is considered be an important virulent determinant. It was suggested that the unique acid tolerance of Shigella boydii 18 CDPH, the strain implicated in a 1998 outbreak, may have played an important role in surviving the acidic food (bean salad). The strain was capable of inducing arginine-dependent acid-resistance (ADAR) pathway. This pathway was assumed to be absent in Shigella sp. Here, we have examined occurrence and efficacy of ADAR pathway in 21 S. boydii strains obtained from the American Type Culture Collection (ATCC) along with strains of S. flexneri (n = 7), S. sonnei (n = 4), and S. dysenteriae (n = 2). The eight S. boydii strains were able to induce ADAR to survive ... Archives of Microbiology journals http://www.medworm.com/rss/comments.php?id=4251399 Tue, 07 Dec 2010 00:00:00 +0100 4251399 http://www.medworm.com/index.php?rid=4251398&cid=s_37326_77_f&fid=37326&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21136042%26dopt%3DAbstract Authors: Berrada ZL, Telford Iii SR Martha's Vineyard (MV), Massachusetts has been the location of two outbreaks of pneumonic tularemia; landscaping activities have been associated with risk, suggesting environmental inhalation exposure. We determined whether salinity or other components of brackish-water present in a location with endemic tularemia may prolong survival of F. tularensis. In addition, we demonstrate for the first time that F. tularensis Type A appears similar to Type B with respect to environmental stability. The results of this study suggest an explanation for why MV is the site of pneumonic tularemia transmission as opposed to sites in the southcentral USA, where tularemia is more commonly reported: Bacteria may be more prone to surviving in salt-influenced soil or mo... Archives of Microbiology journals http://www.medworm.com/rss/comments.php?id=4251398 Tue, 07 Dec 2010 00:00:00 +0100 4251398 http://www.medworm.com/index.php?rid=4251401&cid=s_37326_77_f&fid=37326&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21132276%26dopt%3DAbstract Authors: Naghmouchi K, Paterson L, Forster B, McAllister T, Ohene-Adjei S, Drider D, Teather R, Baah J The aim of this study was to isolate a novel bacterial strain with strong and broad spectrum antibacterial activity from a livestock feed prebiotic supplement. A novel strain, termed Paenibacillus polymyxa JB05-01-1, was isolated using traditional microbiological methods and identified on the basis of its phenotypic and biochemical properties as well as its 16S rRNA gene sequence. This strain was able to inhibit growth of gram-negative bacteria including Escherichia coli RR1, Pseudomonas fluorescens R73, Pantoea agglomerans BC1, Butyrivibrio fibrisolvens OR85, and Fibrobacter succinogenes. The above antagonism against the aforementioned bacteria was attributed to production of an anti... Archives of Microbiology journals http://www.medworm.com/rss/comments.php?id=4251401 Sat, 04 Dec 2010 00:00:00 +0100 4251401 http://www.medworm.com/index.php?rid=4218994&cid=s_37326_77_f&fid=37326&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21104179%26dopt%3DAbstract Authors: Laguna R, Tabita FR, Alber BE Rhodobacter sphaeroides ribulose-1,5-bisphosphate carboxylase/oxygenase (RubisCO)-deletion strain 16 was capable of photoheterotrophic growth with acetate, while Rhodopseudomonas palustris RubisCO-deletion strain 2040 could not grow under these conditions. The reason for this difference lies in the fact that Rba. sphaeroides and Rps. palustris use different pathways for acetate assimilation, the ethylmalonyl-CoA pathway, and glyoxylate-bypass cycle, respectively. The ethylmalonyl-CoA pathway is distinct from the glyoxylate cycle as one molecule of CO(2) and one molecule of HCO(3) (-) per three molecules of acetyl-CoA are co-assimilated to form two malate molecules. The glyoxylate cycle directly converts two acetyl-CoA molecules to malate. Each pat... Archives of Microbiology journals http://www.medworm.com/rss/comments.php?id=4218994 Sun, 21 Nov 2010 00:00:00 +0100 4218994 http://www.medworm.com/index.php?rid=4218995&cid=s_37326_77_f&fid=37326&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21103984%26dopt%3DAbstract This report demonstrates the importance of levansucrase in environmental adaptation of G. diazotrophicus under high osmotic stress and in biofilm formation. PMID: 21103984 [PubMed - as supplied by publisher] (Source: Archives of Microbiology) Archives of Microbiology journals http://www.medworm.com/rss/comments.php?id=4218995 Sat, 20 Nov 2010 00:00:00 +0100 4218995 http://www.medworm.com/index.php?rid=4185841&cid=s_37326_77_f&fid=37326&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21088825%26dopt%3DAbstract This study investigated parameters governing desiccation tolerance of S. aureus and identified several components involved in the process. Initially, the role of environmental parameters such as temperature, growth phase, cell density, desiccation time and protectants in desiccation tolerance were determined. This established a robust model of desiccation tolerance in which S. aureus has the ability to survive on dry plastic surfaces for more than 1,097 days. Using a combination of a random screen and defined mutants, clpX, sigB and yjbH were identified as being required for desiccation tolerance. ClpX is a part of the ATP-dependent ClpXP protease, important for protein turnover, and YjbH has a proposed linked function. SigB is an accessory sigma factor with a role in generalized stress r... Archives of Microbiology journals http://www.medworm.com/rss/comments.php?id=4185841 Fri, 19 Nov 2010 00:00:00 +0100 4185841 http://www.medworm.com/index.php?rid=4185842&cid=s_37326_77_f&fid=37326&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21082309%26dopt%3DAbstract Authors: Ourarhi M, Abdelmoumen H, Guerrouj K, Benata H, Muresu R, Squartini A, Missbah El Idrissi M Eighteen isolates of rhizobia isolated from root nodules of Colutea arborescens (Bladder senna) grown in different soils of the eastern area of Morocco were characterized by phenotypic and genomic analyses. All the isolates characterized were fast growers. This is may be due to the isolation procedures used. The phenotypic, symbiotic and cultural characteristics analyzed allowed the description of a wide physiological diversity among tested isolates. The results obtained suggest that the phenotype of these rhizobia might have convergent evolved to adapt the local conditions. The genetic characterization consisted in an analysis of the rep-PCR fingerprints and the PCR-based RFLP of the 1... Archives of Microbiology journals http://www.medworm.com/rss/comments.php?id=4185842 Wed, 17 Nov 2010 00:00:00 +0100 4185842 http://www.medworm.com/index.php?rid=4185843&cid=s_37326_77_f&fid=37326&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21080156%26dopt%3DAbstract Authors: Sagripanti JL, Carrera M, Robertson J, Levy A, Inglis TJ The size and density of microbial cells determine the time that pathogens can remain airborne and thus, their potential to infect by the respiratory route. We determined the density and size distribution of Burkholderia pseudomallei cells in comparison with other Burkholderia species, including B. mallei and B. thailandensis, all prepared and analyzed under similar conditions. The observed size distribution and densities of several bacterial strains indicates that aerosolized particles consisting of one or of a few B. pseudomallei cells should be efficiently retained in the lungs, highlighting the risk of transmission of melioidosis by the respiratory route when the pathogen is present in fluids from infected patients or... Archives of Microbiology journals http://www.medworm.com/rss/comments.php?id=4185843 Tue, 16 Nov 2010 00:00:00 +0100 4185843 http://www.medworm.com/index.php?rid=4185844&cid=s_37326_77_f&fid=37326&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21076816%26dopt%3DAbstract This study suggests that human-contaminated environments may influence bacterioplankton diversity. PMID: 21076816 [PubMed - as supplied by publisher] (Source: Archives of Microbiology) Archives of Microbiology journals http://www.medworm.com/rss/comments.php?id=4185844 Sat, 13 Nov 2010 00:00:00 +0100 4185844 http://www.medworm.com/index.php?rid=4167124&cid=s_37326_77_f&fid=37326&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21069297%26dopt%3DAbstract Authors: Malla S, Thuy TT, Oh TJ, Sohng JK The macrolide antibiotics are biosynthesized by initial assembly of a macrolactone ring, followed by a series of post-polyketide (PKS) modifications. In general, the additional hydroxyl or epoxy groups are installed by cytochrome P450 enzymes, improving the bioactivity profile through structural diversification of natural products. The biosynthetic gene cluster for the 16-membered macrolide antibiotic dihydrochalcomycin (DHC) has been cloned from Streptomyces sp. KCTC 0041BP. Three cytochrome P450 genes are found in the DHC biosynthetic gene (ger) cluster. Two P450 enzymes were characterized from this cluster. Disruption of gerPI accumulated predominantly 12,13-de-epoxydihydrochalcomycin while disruption of gerPII accumulated 8-dehydroxy-12,13... Archives of Microbiology journals http://www.medworm.com/rss/comments.php?id=4167124 Thu, 11 Nov 2010 00:00:00 +0100 4167124 http://www.medworm.com/index.php?rid=4167125&cid=s_37326_77_f&fid=37326&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21063867%26dopt%3DAbstract Authors: El Gheriany IA, Bocioaga D, Hay AG, Ghiorse WC, Shuler ML, Lion LW In an effort to improve understanding of the role of Cu(II) in bacterial Mn(II) oxidation, a model Mn(II)-oxidizing bacterium, Leptothrix discophora SS-1, was grown in presence of toxic and non-toxic concentrations of Cu(II), Cd(II) and Mn(II). Mn(II)-oxidizing activity increased by 40% when cells were grown in the presence of 0.05 μM of Cu(II) and increased twofold at 0.18 μM Cu(II). Toxic levels of Cd(II) did not stimulate Mn(II) oxidizing activity, indicating that Mn(II) oxidation is not a response to metal toxicity. Stimulation by Cu(II) confirms the specific role of Cu(II) in Mn(II) oxidation. Comparison of transcript levels of the multicopper oxidase mofA gene in the presence and absence of added Cu(I... Archives of Microbiology journals http://www.medworm.com/rss/comments.php?id=4167125 Wed, 10 Nov 2010 00:00:00 +0100 4167125 http://www.medworm.com/index.php?rid=4167126&cid=s_37326_77_f&fid=37326&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21060994%26dopt%3DAbstract Authors: Yamazaki Y, Fukasawa A To distinguish between Escherichia coli and other bacteria that have similar biochemical characteristics, 3 polymerase chain reaction techniques were combined. The primer sets cydA-F2-A2 and cydA-R2-A2 were designed to amplify 605 base pairs of nucleotide sequence specific for the cydA gene of Escherichia coli; primer sets lacZ-F-A and lacZ-R-A to amplify 1,023 bp of nucleotide sequence specific for the lacZ gene of Escherichia coli; and primers lacA-F2-A2 and lacA-R2-A2 to amplify 325 bp of nucleotide sequence specific for the lacA gene of Escherichia coli. As a result, 3 nucleotide fragments were generated when 3 samples DNA from Escherichia coli were used as template. On the other hand, 1,023- and 605-bp products were obtained when DNA of Shigella s... Archives of Microbiology journals http://www.medworm.com/rss/comments.php?id=4167126 Tue, 09 Nov 2010 00:00:00 +0100 4167126 http://www.medworm.com/index.php?rid=4139699&cid=s_37326_77_f&fid=37326&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21046072%26dopt%3DAbstract This study provides some evidences hinting that differences in death mechanism in responses to V. alginolyticus infection may be attributed to the species of infected cells from which it was derived. PMID: 21046072 [PubMed - as supplied by publisher] (Source: Archives of Microbiology) Archives of Microbiology journals http://www.medworm.com/rss/comments.php?id=4139699 Wed, 03 Nov 2010 00:00:00 +0100 4139699 http://www.medworm.com/index.php?rid=4123805&cid=s_37326_77_f&fid=37326&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20978742%26dopt%3DAbstract Authors: Nielsen JS, Christiansen MH, Bonde M, Gottschalk S, Frees D, Thomsen LE, Kallipolitis BH In recent years, small RNAs (sRNAs) have been identified as important regulators of gene expression in bacteria. Most sRNAs are encoded from intergenic regions and are only expressed under highly specific growth conditions. In Staphylococcus aureus, the alternative sigma factor, σ(B), is known to contribute to the overall stress response, antibiotic resistance, and virulence. The σ(B) regulon in S. aureus is well described and comprises approximately 200 annotated genes, including several genes encoding virulence factors. In the present study, we have identified three novel σ(B)-dependent transcripts encoded from genomic regions previously annotated as intergenic. All three transcripts,... Archives of Microbiology journals http://www.medworm.com/rss/comments.php?id=4123805 Wed, 27 Oct 2010 00:00:00 +0100 4123805 http://www.medworm.com/index.php?rid=4123804&cid=s_37326_77_f&fid=37326&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20978743%26dopt%3DAbstract Authors: Wolny D, Lodowska J, Jaworska-Kik M, Kurkiewicz S, Węglarz L, Dzierżewicz Z Lipopolysaccharides also called endotoxins are an integral component of the outer membrane of Gram-negative bacteria. When released from the bacterial surface, they interact with a host immune system, triggering excessive inflammatory response. Lipid A is the biologically most active part of endotoxin, and its activity is modulated by the quantity, quality and arrangement of its fatty acids. Desulfovibrio desulfuricans is sulfate-reducing, Gram-negative bacterium that is supposed to be opportunistic pathogens of humans and animals. In the present study, chemical composition of lipid A from various strains of D. desulfuricans was analyzed by gas chromatography/mass spectrometry. It was found that the ... Archives of Microbiology journals http://www.medworm.com/rss/comments.php?id=4123804 Wed, 27 Oct 2010 00:00:00 +0100 4123804 http://www.medworm.com/index.php?rid=4123803&cid=s_37326_77_f&fid=37326&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20978744%26dopt%3DAbstract Authors: Osburn MR, Amend JP A hyperthermophilic heterotrophic archaeon (strain WB1) was isolated from a thermal pool in the Washburn hot spring group of Yellowstone National Park, USA. WB1 is a coccus, 0.6-1.2 μm in diameter, with a tetragonal S-layer, vacuoles, and occasional stalk-like protrusions. Growth is optimal at 84°C (range 64-93°C), pH 5-6 (range 3.5-8.5), and <1 g/l NaCl (range 0-4.6 g/l NaCl). Tests of metabolic properties show the isolate to be a strict anaerobe that ferments complex organic substrates. Phylogenetic analysis of the 16S rRNA gene sequence places WB1 in a clade of previously uncultured Desulfurococcaceae and shows it to have ≤96% 16S rRNA sequence identity to Desulfurococcus mobilis, Staphylothermus marinus, Staphylothermus hellenicus, and Sulfop... Archives of Microbiology journals http://www.medworm.com/rss/comments.php?id=4123803 Wed, 27 Oct 2010 00:00:00 +0100 4123803 http://www.medworm.com/index.php?rid=4123802&cid=s_37326_77_f&fid=37326&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20978745%26dopt%3DAbstract Authors: Ammar ED, Gasparich GE, Hall DG, Hogenhout SA Spiroplasmas are bacteria in the Class Mollicutes that are frequently associated with insects and/or plants. Here, we describe the ultrastructure, localization, and occurrence of apparent commensal/symbiotic spiroplasma-like organisms (SLOs) in the midgut and hindgut of five leafhopper species from laboratory-reared colonies. Those found in Dalbulus elimatus, Endria inimica, and Macrosteles quadrilineatus were long and tubular shaped, whereas those in Dalbulus maidis and Graminella nigrifrons were shorter and mostly rod-shaped in their host organisms. These SLOs were found in great numbers in the gut lumen frequently associated with the gut microvilli, but unlike the plant-pathogenic mollicutes, they did not seem to invade the gut ... Archives of Microbiology journals http://www.medworm.com/rss/comments.php?id=4123802 Wed, 27 Oct 2010 00:00:00 +0100 4123802 http://www.medworm.com/index.php?rid=4088511&cid=s_37326_77_f&fid=37326&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20967536%26dopt%3DAbstract Authors: Fanget NV, Foley S The adaptation of Rhodocccus erythropolis SQ1 to energy and carbon starvation was investigated in terms of both the capacity to survive starvation and the contribution of a nutrient-induced stationary phase to cross-protection to other types of environmental stress. It was found that R. erythropolis SQ1 survives for at least 43 days in LB and distilled water, and 65 days in chemically defined medium (CDM) containing high (1%) or low (0.1%) glucose. Furthermore, early stationary-phase R. erythropolis SQ1 grown in CDM 0.1% exhibited enhanced resistance to heat and oxidative stress compared with exponential-phase cells. A second objective of this study was to identify genetic elements involved in starvation/stationary-phase survival. A mutant bank of R. eryth... Archives of Microbiology journals http://www.medworm.com/rss/comments.php?id=4088511 Thu, 21 Oct 2010 23:00:00 +0100 4088511 http://www.medworm.com/index.php?rid=4088512&cid=s_37326_77_f&fid=37326&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20957348%26dopt%3DAbstract Authors: Ismail B, Nampoothiri KM Exopolysaccharides (EPS) from lactic acid bacteria contribute to specific rheology and texture of fermented milk products and finds applications even in non-dairy foods and in therapeutics. Box-Behnken model of response surface methodology (RSM) was employed to formulate the production medium for exopolysaccharide (EPS). FT-IR spectral analysis of the purified EPS from Lactobacillus plantarum MTCC 9510 revealed prominent characteristic groups corresponding to polyhydric alcohols. The degradation temperature (Td) of the polysaccharide was found to be 260°C with the help of thermo gravimetric analysis (TGA). Structure elucidation of the EPS showed that it consists of a trisaccharide repeating unit of α-D: -glucose, β-D: -glucose and α-D: -mannose. ... Archives of Microbiology journals http://www.medworm.com/rss/comments.php?id=4088512 Mon, 18 Oct 2010 23:00:00 +0100 4088512 http://www.medworm.com/index.php?rid=4063070&cid=s_37326_77_f&fid=37326&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20938646%26dopt%3DAbstract Authors: Xu L, Wang Q, Xiao J, Liu Q, Wang X, Chen T, Zhang Y Edwardsiella tarda is the causative agent of edwardsiellosis in fish. The genome sequence of a virulent strain EIB202 has been determined. According to the genome sequence, the lipopolysaccharide (LPS) synthesis cluster containing a putative O-antigen ligase gene waaL was identified. Here, the in-frame deletion mutant ΔwaaL was constructed to analyze the function of WaaL in E. tarda EIB202. The ΔwaaL mutant displayed absence in O-antigen side chains in the LPS production. The ΔwaaL mutant exhibited an increased sensitivity to hydrogen peroxide indicating that the LPS was involved in the endurance to the oxidative stress in hosts during infection. In addition, the resistance of ΔwaaL to serum and polymyxin B decreased rem... Archives of Microbiology journals http://www.medworm.com/rss/comments.php?id=4063070 Mon, 11 Oct 2010 23:00:00 +0100 4063070 http://www.medworm.com/index.php?rid=4063071&cid=s_37326_77_f&fid=37326&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20936259%26dopt%3DAbstract The objective of this study was to determine the compatible solutes that are accumulated by cyanobacteria from hypersaline regions, and specifically, the stromatolite ecosystems of Shark Bay, Western Australia. Previously, the cyanobacterial populations associated with these stromatolites were characterized in two separate studies. Compatible solutes were extracted from isolated cyanobacteria here and identified by nuclear magnetic resonance. As the media of isolation contained no complex carbon source, the solutes accumulated were likely synthesized by the cyanobacteria. The data indicate that from this one habitat taxonomically distinct cyanobacteria exposed to varying salinities accumulate a range of known compatible solutes. In addition, taxonomically similar cyanobacteria do not neces... Archives of Microbiology journals http://www.medworm.com/rss/comments.php?id=4063071 Fri, 08 Oct 2010 23:00:00 +0100 4063071 http://www.medworm.com/index.php?rid=4026605&cid=s_37326_77_f&fid=37326&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20878147%26dopt%3DAbstract Authors: Pardo A, Emilio Pardo J, de Juan JA, Zied DC The aim of this research was to show the mathematical data obtained through the correlations found between the physical and chemical characteristics of casing layers and the final mushrooms' properties. For this purpose, 8 casing layers were used: soil, soil + peat moss, soil + black peat, soil + composted pine bark, soil + coconut fibre pith, soil + wood fibre, soil + composted vine shoots and, finally, the casing of La Rioja subjected to the ruffling practice. The conclusion that interplays in the fructification process with only the physical and chemical characteristics of casing are complicated was drawn. The mathematical data obtained in earliness could be explained in non-ruffled cultivation... Archives of Microbiology journals http://www.medworm.com/rss/comments.php?id=4026605 Mon, 27 Sep 2010 23:00:00 +0100 4026605 http://www.medworm.com/index.php?rid=4003612&cid=s_37326_77_f&fid=37326&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20872263%26dopt%3DAbstract Authors: Augustine N, Kumar P, Thomas S Vibrio cholerae is the causative agent of water-borne diarrheal disease, cholera. The formation of biofilm favors survival and persistence of V. cholerae in the aquatic environment and also inside the host. AHL lactonase (AiiA), a metallo-beta-lactamase produced by Bacillus spp., blocks quorum sensing in Gram-negative bacteria by hydrolyzing N-acyl-homoserine lactones (AHLs). In the present investigation, AiiA-mediated inhibition of V. cholerae biofilm was studied. Two novel alleles of aiiA-encoding genes from Bacillus spp. were expressed in E. coli, and the results demonstrated that AiiA enzyme is a potent inhibitor of V. cholerae biofilm. PMID: 20872263 [PubMed - as supplied by publisher] (Source: Archives of Microbiology) Archives of Microbiology journals http://www.medworm.com/rss/comments.php?id=4003612 Sat, 25 Sep 2010 23:00:00 +0100 4003612 http://www.medworm.com/index.php?rid=4003802&cid=s_37326_77_f&fid=37326&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20857088%26dopt%3DAbstract Authors: Morel MA, Ubalde MC, Braña V, Castro-Sowinski S A chromium (Cr)-resistant bacterium isolated from soil containing 6,000 mg/kg of Cr was identified based on 16S rRNA gene sequence analysis as Delftia, and designated as JD2. Growth of JD2 was accompanied with reduction of Cr(VI) to Cr(III) in liquid medium initially containing 100 mg/L Cr(VI), the maximum concentration allowing growth. JD2 showed NADH/NADPH-dependent reductase activity associated with the soluble fraction of cells. The results suggest that JD2 might be a good candidate for the treatment of highly Cr(VI)-contaminated water and/or industrial effluents. The isolate produced indole-3-acetic acid in the presence and absence of Cr(VI) and showed free-living nitrogen-fixing activity possibly attributable to a ... Archives of Microbiology journals http://www.medworm.com/rss/comments.php?id=4003802 Mon, 20 Sep 2010 23:00:00 +0100 4003802 http://www.medworm.com/index.php?rid=4003895&cid=s_37326_77_f&fid=37326&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20852847%26dopt%3DAbstract Authors: Mykytczuk NC, Trevors JT, Twine SM, Ferroni GD, Leduc LG Psychrotrophic strains of Acidithiobacillus ferrooxidans have an important role in metal leaching and acid mine drainage (AMD) production in colder mining environments. We investigated cytoplasmic membrane fluidity and fatty acid alterations in response to low temperatures (5 and 15°C). Significant differences in membrane fluidity, measured by polarization (P) of 1,6-diphenyl-1,3,5-hexatriene (DPH), were found where the psychrotrophic strains had a significantly more rigid membrane (P range = 0.41-0.45) and lower transition temperature midpoints (T (m) = 2.0°C) and broader transition range than the mesophilic strains (P range = 0.38-0.39; T (m) = 2.0-18°C) at cold temperatures. Membrane r... Archives of Microbiology journals http://www.medworm.com/rss/comments.php?id=4003895 Fri, 17 Sep 2010 23:00:00 +0100 4003895 http://www.medworm.com/index.php?rid=4003963&cid=s_37326_77_f&fid=37326&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20848082%26dopt%3DAbstract Authors: Martins AK, Martins FS, Gomes DA, Elian SD, Vieira AT, Teixeira MM, Cara DC, Nardi RM, Nicoli JR The aim of the present study was to compare the effect of intragastric administration with two strains of Bifidobacterium animalis subsp. lactis (Bifido A and Bifido B), in gnotobiotic and conventional mice, challenged with Salmonella Typhimurium. In vitro antagonism test showed that the two strains were able to produce antagonistic substances against various pathogenic microorganisms. In an ex vivo antagonism test the production of antagonistic substances was observed only against three out ten pathogens tested. Both Bifidobacterium strains were able to colonize and to maintain high population levels in the digestive tract of gnotobiotic mice. In addition, the two strains ha... Archives of Microbiology journals http://www.medworm.com/rss/comments.php?id=4003963 Thu, 16 Sep 2010 23:00:00 +0100 4003963 http://www.medworm.com/index.php?rid=4004156&cid=s_37326_77_f&fid=37326&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20844865%26dopt%3DAbstract We present data demonstrating that the extracytoplasmic function sigma factor σ(X) controls resistance to β-lactam antibiotics by activating abh transcription. Downstream from Abh, activation of slrR expression by Abh is responsible for controlling the sensitivity of B. subtilis to such antibiotics due to the role that SlrR plays in regulating autolysin biosynthesis. The abh mutant additionally exhibits increased resistance to aminoglycoside antimicrobials. We confirm that aminoglycoside killing of B. subtilis is likely to be caused by oxidative damage but rule out the possibility that the increased resistance of the abh mutant to aminoglycosides is due to a general increase in resistance to oxidative stress. PMID: 20844865 [PubMed - as supplied by publisher] (Source: Archives of... Archives of Microbiology journals http://www.medworm.com/rss/comments.php?id=4004156 Wed, 15 Sep 2010 23:00:00 +0100 4004156