Journal of Bacteriology最新文献

{"title":"Regulation of potassium uptake in <i>Caulobacter crescentus</i>.","authors":"Alex Quintero-Yanes, Loïc Léger, Madeline Collignon, Julien Mignon, Aurélie Mayard, Catherine Michaux, Régis Hallez","doi":"10.1128/jb.00107-24","DOIUrl":"10.1128/jb.00107-24","url":null,"abstract":"<p><p>Potassium (K⁺) is an essential physiological element determining membrane potential, intracellular pH, osmotic/turgor pressure, and protein synthesis in cells. Here, we describe the regulation of potassium uptake systems in the oligotrophic α-proteobacterium <i>Caulobacter crescentus</i> known as a model for asymmetric cell division. We show that <i>C. crescentus</i> can grow in concentrations from the micromolar to the millimolar range by mainly using two K⁺ transporters to maintain potassium homeostasis, the low-affinity Kup and the high-affinity Kdp uptake systems. When K⁺ is not limiting, we found that the <i>kup</i> gene is essential while <i>kdp</i> inactivation does not impact the growth. In contrast, <i>kdp</i> becomes critical but not essential and <i>kup</i> dispensable for growth in K⁺-limited environments. However, in the absence of <i>kdp</i>, mutations in <i>kup</i> were selected to improve growth in K⁺-depleted conditions, likely by increasing the affinity of Kup for K⁺. In addition, mutations in the KdpDE two-component system, which regulates <i>kdpABCDE</i> expression, suggest that the inner membrane sensor regulatory component KdpD mainly works as a phosphatase to limit the growth when cells reach late exponential phase. Our data therefore suggest that KdpE is phosphorylated by another non-cognate histidine kinase. On top of this, we determined the KdpE-dependent and independent K⁺ transcriptome. Together, our work illustrates how an oligotrophic bacterium responds to fluctuation in K⁺ availability.IMPORTANCEPotassium (K⁺) is a key metal ion involved in many essential cellular processes. Here, we show that the oligotroph <i>Caulobacter crescentus</i> can support growth at micromolar concentrations of K⁺ by mainly using two K⁺ uptake systems, the low-affinity Kup and the high-affinity Kdp. Using genome-wide approaches, we also determined the entire set of genes required for <i>C. crescentus</i> to survive at low K⁺ concentration as well as the full K⁺-dependent regulon. Finally, we found that the transcriptional regulation mediated by the KdpDE two-component system is unconventional since unlike <i>Escherichia coli</i>, the inner membrane sensor regulatory component KdpD seems to work rather as a phosphatase on the phosphorylated response regulator KdpE~P.</p>","PeriodicalId":15107,"journal":{"name":"Journal of Bacteriology","volume":" ","pages":"e0010724"},"PeriodicalIF":2.7,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11411941/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141916734","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"TolC and EmrA1 contribute to <i>Francisella novicida</i> multidrug resistance and modulation of host cell death.","authors":"Erik J Kopping, P Todd Benziger, David G Thanassi","doi":"10.1128/jb.00246-24","DOIUrl":"10.1128/jb.00246-24","url":null,"abstract":"<p><p><i>Francisella</i> spp. are Gram-negative, facultative intracellular pathogens. <i>Francisella tularensis</i> causes the human disease tularemia and is considered a biological threat agent due to its high infectivity and virulence. A central aspect of <i>Francisella</i> virulence is its ability to dampen host immune responses. We previously identified the outer membrane channel (OMC) protein TolC as a critical <i>F. tularensis</i> virulence factor required for suppression of apoptotic and proinflammatory responses during macrophage infection. TolC functions as part of multidrug efflux systems and the type I secretion pathway that exports bacterial effector proteins. In these systems, TolC forms tripartite complexes together with an inner membrane transporter and periplasmic membrane fusion protein (MFP). To advance understanding of TolC function in <i>Francisella</i>, we analyzed OMC and MFP homologs in <i>Francisella novicida</i>, a widely used model species that causes a tularemia-like disease in mice. In agreement with the previous <i>F. tularensis</i> studies, all three OMCs present in <i>F. novicida</i> contributed to multidrug resistance, but only TolC was important for suppressing macrophage cell death. In addition, we identified the EmrA1 MFP as important for resisting antimicrobial compounds and dampening host cell death. In contrast to results obtained with <i>F. tularensis</i>, the cell death triggered during infection with the <i>F. novicida tolC</i> and <i>emrA1</i> mutants was dominated by pyroptosis rather than apoptosis. These data expand our understanding of TolC function in <i>Francisella</i> and underscore both conserved and differential aspects of <i>F. novicida</i> and <i>F. tularensis</i>.</p><p><strong>Importance: </strong><i>Francisella tularensis</i> is a Gram-negative intracellular bacterial pathogen and causative agent of tularemia. We previously identified the outer membrane channel protein TolC as contributing to antimicrobial resistance and subversion of host responses by <i>F. tularensis</i>. To advance understanding of TolC function in <i>Francisella</i> and to identify components that might work together with TolC, we took advantage of a transposon mutant library in <i>F. novicida</i>, a model species that causes a tularemia-like disease in mice. Our findings identify TolC and the membrane fusion protein EmrA1 as important for both antimicrobial resistance and suppression of macrophage cell death. This study also revealed differences in cell death pathways triggered by <i>F. novicida</i> versus <i>F. tularensis</i> infection that may relate to differences in virulence.</p>","PeriodicalId":15107,"journal":{"name":"Journal of Bacteriology","volume":" ","pages":"e0024624"},"PeriodicalIF":2.7,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11411944/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142080392","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Modulation of Vibrio cholerae gene expression through conjugative delivery of engineered regulatory small RNAs","authors":"Pilar Menendez-GilDiana VelevaMollie VirgoJige ZhangRita RamalheteBrian T. Ho1Department of Biological Sciences, Institute of Structural and Molecular Biology, Birkbeck College, London, United Kingdom2Division of Biosciences, Institute of Structural and Molecular Biology, University College London, London, United KingdomLaurie E. Comstock","doi":"10.1128/jb.00142-24","DOIUrl":"https://doi.org/10.1128/jb.00142-24","url":null,"abstract":"Journal of Bacteriology, Ahead of Print. <br/>","PeriodicalId":15107,"journal":{"name":"Journal of Bacteriology","volume":"77 1","pages":""},"PeriodicalIF":3.2,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142267922","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The cell division protein FzlA performs a conserved function in diverse alphaproteobacteria","authors":"Isaac P. PayneBrody AubryJordan M. BarrowsPamela J. B. BrownErin D. Goley1Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA2Division of Biological Sciences, University of Missouri, Columbia, Missouri, USAConrad W. Mullineaux","doi":"10.1128/jb.00225-24","DOIUrl":"https://doi.org/10.1128/jb.00225-24","url":null,"abstract":"Journal of Bacteriology, Ahead of Print. <br/>","PeriodicalId":15107,"journal":{"name":"Journal of Bacteriology","volume":"1 1","pages":""},"PeriodicalIF":3.2,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142267974","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Regulation of bacterial virulence genes by PecS family transcription factors","authors":"George C. NwokochaArpita GhoshAnne Grove1Corteva Agriscience, Johnston, Iowa, USA2Department of Biological Sciences, Louisiana State University, Baton Rouge, Louisiana, USAGeorge O'Toole","doi":"10.1128/jb.00302-24","DOIUrl":"https://doi.org/10.1128/jb.00302-24","url":null,"abstract":"Journal of Bacteriology, Ahead of Print. <br/>","PeriodicalId":15107,"journal":{"name":"Journal of Bacteriology","volume":"208 1","pages":""},"PeriodicalIF":3.2,"publicationDate":"2024-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142267973","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"In vivo and in vitro analyses of the role of the Prc protease in inducing mucoidy in Pseudomonas aeruginosa","authors":"Alexis G. SommerfieldMichelle WangJulia MamanaAndrew J. Darwin1Department of Microbiology, NYU Grossman School of Medicine, New York, New York, USAJoseph Bondy-Denomy","doi":"10.1128/jb.00222-24","DOIUrl":"https://doi.org/10.1128/jb.00222-24","url":null,"abstract":"Journal of Bacteriology, Ahead of Print. <br/>","PeriodicalId":15107,"journal":{"name":"Journal of Bacteriology","volume":"33 1","pages":""},"PeriodicalIF":3.2,"publicationDate":"2024-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142267923","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Hybrid Exb/Mot stators require substitutions distant from the chimeric pore to power flagellar rotation","authors":"Pietro RidoneMatthew A. B. Baker1School of Biotechnology and Biomolecular Sciences, UNSW, Kensington, AustraliaMichael Y. Galperin","doi":"10.1128/jb.00140-24","DOIUrl":"https://doi.org/10.1128/jb.00140-24","url":null,"abstract":"Journal of Bacteriology, Ahead of Print. <br/>","PeriodicalId":15107,"journal":{"name":"Journal of Bacteriology","volume":"20 1","pages":""},"PeriodicalIF":3.2,"publicationDate":"2024-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142267924","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Substrate dependence of transport coupling and phenotype of a small multidrug resistance transporter in Pseudomonas aeruginosa","authors":"Andrea K. WegrzynowiczWilliam J. HeelanSydnye P. DemasMaxwell S. McLeanJason M. PetersKatherine A. Henzler-Wildman1Department of Biochemistry, University of Wisconsin—Madison, Madison, Wisconsin, USA2Department of Obstetrics and Gynecology, University of Wisconsin-Madison, Madison, Wisconsin, USA3Pharmaceutical Sciences Division, School of Pharmacy, University of Wisconsin—Madison, Madison, Wisconsin, USA4DOE Great Lakes Bioenergy Research Center, University of Wisconsin—Madison, Madison, Wisconsin, USA5Department of Bacteriology, University of Wisconsin—Madison, Madison, Wisconsin, USA6Department of Medical Microbiology and Immunology, University of Wisconsin—Madison, Madison, Wisconsin, USA7Center for Genomic Science Innovation, University of Wisconsin—Madison, Madison, Wisconsin, USA8National Magnetic Resonance Facility at Madison, Madison, Wisconsin, USAGeorge O'Toole","doi":"10.1128/jb.00151-24","DOIUrl":"https://doi.org/10.1128/jb.00151-24","url":null,"abstract":"Journal of Bacteriology, Ahead of Print. <br/>","PeriodicalId":15107,"journal":{"name":"Journal of Bacteriology","volume":"3 1","pages":""},"PeriodicalIF":3.2,"publicationDate":"2024-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142225685","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"An exopolysaccharide pathway from a freshwater <i>Sphingomonas</i> isolate.","authors":"Alexandra G Goetsch, Daniel Ufearo, Griffin Keiser, Christian Heiss, Parastoo Azadi, David M Hershey","doi":"10.1128/jb.00169-24","DOIUrl":"10.1128/jb.00169-24","url":null,"abstract":"<p><p>Bacteria embellish their cell envelopes with a variety of specialized polysaccharides. Biosynthesis pathways for these glycans are complex, and final products vary greatly in their chemical structures, physical properties, and biological activities. This tremendous diversity comes from the ability to arrange complex pools of monosaccharide building blocks into polymers with many possible linkage configurations. Due to the complex chemistry of bacterial glycans, very few biosynthetic pathways have been defined in detail. As part of an initiative to characterize novel polysaccharide biosynthesis enzymes, we isolated a bacterium from Lake Michigan called <i>Sphingomonas</i> sp. LM7 that is proficient in exopolysaccharide (EPS) production. We identified genes that contribute to EPS biosynthesis in LM7 by screening a transposon mutant library for colonies displaying altered colony morphology. A gene cluster was identified that appears to encode a complete <i>wzy/wzx-</i>dependent polysaccharide assembly pathway. Deleting individual genes in this cluster caused a non-mucoid phenotype and a corresponding loss of EPS secretion, confirming the role of this gene cluster in polysaccharide production. We extracted EPS from LM7 cultures and determined that it contains a linear chain of 3- and 4-linked glucose, galactose, and glucuronic acid residues. Finally, we show that the EPS pathway in <i>Sphingomonas</i> sp. LM7 diverges from that of sphingan-family EPSs and adhesive polysaccharides such as the holdfast that are present in other <i>Alphaproteobacteria</i>. Our approach of characterizing complete biosynthetic pathways holds promise for engineering polysaccharides with valuable properties.</p><p><strong>Importance: </strong>Bacteria produce complex polysaccharides that serve a range of biological functions. These polymers often have properties that make them attractive for industrial applications, but they remain woefully underutilized. In this work, we studied a novel polysaccharide called promonan that is produced by <i>Sphingomonas</i> sp. LM7, a bacterium we isolated from Lake Michigan. We extracted promonan from LM7 cultures and identified which sugars are present in the polymer. We also identified the genes responsible for polysaccharide production. Comparing the promonan genes to those of other bacteria showed that promonan is distinct from previously characterized polysaccharides. We conclude by discussing how the promonan pathway could be used to produce new polysaccharides through genetic engineering.</p>","PeriodicalId":15107,"journal":{"name":"Journal of Bacteriology","volume":" ","pages":"e0016924"},"PeriodicalIF":2.7,"publicationDate":"2024-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11340318/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141616486","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The role of <i>Listeria monocytogenes</i> PstA in β-lactam resistance requires the cytochrome <i>bd</i> oxidase activity.","authors":"Zepeng Tu, David M Stevenson, Darrel McCaslin, Daniel Amador-Noguez, TuAnh N Huynh","doi":"10.1128/jb.00130-24","DOIUrl":"10.1128/jb.00130-24","url":null,"abstract":"<p><p>c-di-AMP is an essential second messenger that binds and regulates several proteins of different functions within bacterial cells. Among those, PstA is a structurally conserved c-di-AMP-binding protein, but its function is largely unknown. PstA is structurally similar to PII signal transduction proteins, although it specifically binds c-di-AMP rather than other PII ligands such as ATP and α-ketoglutarate. In <i>Listeria monocytogenes</i>, we found that PstA increases β-lactam susceptibility at normal and low c-di-AMP levels, but increases β-lactam resistance upon c-di-AMP accumulation. Examining a PstA mutant defective for c-di-AMP binding, we found the apo form of PstA to be toxic for β-lactam resistance, and the c-di-AMP-bound form to be beneficial. Intriguingly, a role for PstA in β-lactam resistance is only prominent in aerobic cultures, and largely diminished under hypoxic conditions, suggesting that PstA function is linked to aerobic metabolism. However, PstA does not control aerobic growth rate, and has a modest influence on the tricarboxylic acid cycle and membrane potential-an indicator of cellular respiration. The regulatory role of PstA in β-lactam resistance is unrelated to reactive oxygen species or oxidative stress. Interestingly, during aerobic growth, PstA function requires the cytochrome <i>bd</i> oxidase (CydAB), a component of the respiratory electron transport chain. The requirement for CydAB might be related to its function in maintaining a membrane potential, or redox stress response activities. Altogether, we propose a model in which apo-PstA diminishes β-lactam resistance by interacting with an effector protein, and this activity can be countered by c-di-AMP binding or a by-product of redox stress.</p><p><strong>Importance: </strong>PstA is a structurally conserved c-di-AMP-binding protein that is broadly present among Firmicutes bacteria. Furthermore, PstA binds c-di-AMP at high affinity and specificity, indicating an important role in the c-di-AMP signaling network. However, the molecular function of PstA remains elusive. Our findings reveal contrasting roles of PstA in β-lactam resistance depending on c-di-AMP-binding status. We also define physiological conditions for PstA function during aerobic growth. Future efforts can exploit these conditions to identify PstA interaction partners under β-lactam stress.</p>","PeriodicalId":15107,"journal":{"name":"Journal of Bacteriology","volume":" ","pages":"e0013024"},"PeriodicalIF":2.7,"publicationDate":"2024-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11340317/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141590415","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}