Journal of Bacteriology最新文献

{"title":"Effects of pleiotropic <i>ompR</i> and <i>envZ</i> alleles of <i>Escherichia coli</i> on envelope stress and antibiotic sensitivity.","authors":"Henri Gerken, Dasvit Shetty, Brea Kern, Linda J Kenney, Rajeev Misra","doi":"10.1128/jb.00172-24","DOIUrl":"10.1128/jb.00172-24","url":null,"abstract":"<p><p>The EnvZ-OmpR two-component system of <i>Escherichia coli</i> regulates the expression of the <i>ompF</i> and <i>ompC</i> porin genes in response to medium osmolarity. However, certain mutations in <i>envZ</i> confer pleiotropy by affecting the expression of genes of the iron and maltose regulons not normally controlled by EnvZ-OmpR. In this study, we obtained two novel <i>envZ</i> and <i>ompR</i> pleiotropic alleles, <i>envZT15P</i> and <i>ompRL19Q</i>, among revertants of a mutant with heightened envelope stress and an outer membrane (OM) permeability defect. Unlike <i>envZ</i>, pleiotropic mutations in <i>ompR</i> have not been described previously. The mutant alleles reduced the expression of several outer membrane proteins (OMPs), overcame the temperature-sensitive growth defect of a protease-deficient (Δ<i>degP</i>) strain, and lowered envelope stress and OM permeability defects in a background lacking the BamB protein of an essential β-barrel assembly machinery complex. Biochemical analysis showed OmpRL19Q, like wild-type OmpR, is readily phosphorylated by EnvZ, but the EnvZ-dependent dephosphorylation of OmpRL19Q~P was drastically impaired compared to wild-type OmpR. This defect would lead to a prolonged half-life for OmpRL19Q~P, an outcome remarkably similar to what we had previously described for EnvZR397L, resulting in pleiotropy. By employing null alleles of the OMP genes, it was determined that the three pleiotropic alleles lowered envelope stress by reducing OmpF and LamB levels. The absence of LamB was principally responsible for lowering the OM permeability defect, as assessed by the reduced sensitivity of a Δ<i>bamB</i> mutant to vancomycin and rifampin. Possible mechanisms by which novel EnvZ and OmpR mutants influence EnvZ-OmpR interactions and activities are discussed.IMPORTANCEMaintenance of the outer membrane (OM) integrity is critical for the survival of Gram-negative bacteria. Several envelope homeostasis systems are activated when OM integrity is perturbed. Through the isolation and characterization of novel pleiotropic <i>ompR</i>/<i>envZ</i> alleles, this study highlights the involvement of the EnvZ-OmpR two-component system in lowering envelope stress and the OM permeability defect caused by the loss of proteins that are involved in OM biogenesis, envelope homeostasis, and structural integrity.</p>","PeriodicalId":15107,"journal":{"name":"Journal of Bacteriology","volume":" ","pages":"e0017224"},"PeriodicalIF":2.7,"publicationDate":"2024-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11332150/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141161792","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":"Erratum for Cinar et al., \"Serine-rich repeat proteins: well-known yet little-understood bacterial adhesins\".","authors":"Mukaddes S Cinar, Afaq Niyas, Fikri Y Avci","doi":"10.1128/jb.00153-24","DOIUrl":"10.1128/jb.00153-24","url":null,"abstract":"","PeriodicalId":15107,"journal":{"name":"Journal of Bacteriology","volume":" ","pages":"e0015324"},"PeriodicalIF":2.7,"publicationDate":"2024-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11332144/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140898226","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":"Involvement of ArlI, ArlJ, and CirA in archaeal type IV pilin-mediated motility regulation.","authors":"Priyanka Chatterjee, Marco A Garcia, Jacob A Cote, Kun Yun, Georgio P Legerme, Rumi Habib, Manuela Tripepi, Criston Young, Daniel Kulp, Mike Dyall-Smith, Mecky Pohlschroder","doi":"10.1128/jb.00089-24","DOIUrl":"10.1128/jb.00089-24","url":null,"abstract":"<p><p>Many prokaryotes use swimming motility to move toward favorable conditions and escape adverse surroundings. Regulatory mechanisms governing bacterial flagella-driven motility are well-established; however, little is yet known about the regulation underlying swimming motility propelled by the archaeal cell surface structure, the archaella. Previous research showed that the deletion of the adhesion pilins (PilA1-6), subunits of the type IV pili cell surface structure, renders the model archaeon <i>Haloferax volcanii</i> non-motile. In this study, we used ethyl methanesulfonate mutagenesis and a motility assay to identify motile suppressors of the ∆<i>pilA</i>[<i>1-6</i>] strain. Of the eight suppressors identified, six contain missense mutations in archaella biosynthesis genes, <i>arlI</i> and <i>arlJ. In trans</i> expression of <i>arlI</i> and <i>arlJ</i> mutant constructs in the respective multi-deletion strains ∆<i>pilA</i>[<i>1-6</i>]∆<i>arlI</i> and ∆<i>pilA</i>[<i>1-6</i>]∆<i>arlJ</i> confirmed their role in suppressing the ∆<i>pilA</i>[<i>1-6</i>] motility defect. Additionally, three suppressors harbor co-occurring disruptive missense and nonsense mutations in <i>cirA</i>, a gene encoding a proposed regulatory protein. A deletion of <i>cirA</i> resulted in hypermotility, while <i>cirA</i> expression <i>in trans</i> in wild-type cells led to decreased motility. Moreover, quantitative real-time PCR analysis revealed that in wild-type cells, higher expression levels of <i>arlI</i>, <i>arlJ</i>, and the archaellin gene <i>arlA1</i> were observed in motile early-log phase rod-shaped cells compared to non-motile mid-log phase disk-shaped cells. Conversely, ∆<i>cirA</i> cells, which form rods during both early- and mid-log phases, exhibited similar expression levels of <i>arl</i> genes in both growth phases. Our findings contribute to a deeper understanding of the mechanisms governing archaeal motility, highlighting the involvement of ArlI, ArlJ, and CirA in pilin-mediated motility regulation.IMPORTANCEArchaea are close relatives of eukaryotes and play crucial ecological roles. Certain behaviors, such as swimming motility, are thought to be important for archaeal environmental adaptation. Archaella, the archaeal motility appendages, are evolutionarily distinct from bacterial flagella, and the regulatory mechanisms driving archaeal motility are largely unknown. Previous research has linked the loss of type IV pili subunits to archaeal motility suppression. This study reveals three <i>Haloferax volcanii</i> proteins involved in pilin-mediated motility regulation, offering a deeper understanding of motility regulation in this understudied domain while also paving the way for uncovering novel mechanisms that govern archaeal motility. Understanding archaeal cellular processes will help elucidate the ecological roles of archaea as well as the evolution of these processes across domains.</p>","PeriodicalId":15107,"journal":{"name":"Journal of Bacteriology","volume":" ","pages":"e0008924"},"PeriodicalIF":2.7,"publicationDate":"2024-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11332145/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141179674","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":"Metabolic flux regulates growth transitions and antibiotic tolerance in uropathogenic <i>Escherichia coli</i>.","authors":"Josiah J Morrison, Ellen K Madden, Daniel A Banas, Eric C DiBiasio, Mads Hansen, Karen A Krogfelt, David C Rowley, Paul S Cohen, Jodi L Camberg","doi":"10.1128/jb.00162-24","DOIUrl":"10.1128/jb.00162-24","url":null,"abstract":"<p><p>Reducing growth and limiting metabolism are strategies that allow bacteria to survive exposure to environmental stress and antibiotics. During infection, uropathogenic <i>Escherichia coli</i> (UPEC) may enter a quiescent state that enables them to reemerge after the completion of successful antibiotic treatment. Many clinical isolates, including the well-characterized UPEC strain CFT073, also enter a metabolite-dependent, quiescent state <i>in vitro</i> that is reversible with cues, including peptidoglycan-derived peptides and amino acids. Here, we show that quiescent UPEC is antibiotic tolerant and demonstrate that metabolic flux in the tricarboxylic acid (TCA) cycle regulates the UPEC quiescent state via succinyl-CoA. We also demonstrate that the transcriptional regulator complex integration host factor and the FtsZ-interacting protein ZapE, which is important for <i>E. coli</i> division during stress, are essential for UPEC to enter the quiescent state. Notably, in addition to engaging FtsZ and late-stage cell division proteins, ZapE also interacts directly with TCA cycle enzymes in bacterial two-hybrid assays. We report direct interactions between the succinate dehydrogenase complex subunit SdhC, the late-stage cell division protein FtsN, and ZapE. These interactions may enable communication between oxidative metabolism and the cell division machinery in UPEC. Moreover, these interactions are conserved in an <i>E. coli</i> K-12 strain. This work suggests that there is coordination among the two fundamental and essential pathways that regulate overall growth, quiescence, and antibiotic susceptibility.</p><p><strong>Importance: </strong>Uropathogenic <i>Escherichia coli</i> (UPEC) are the leading cause of urinary tract infections (UTIs). Upon invasion into bladder epithelial cells, UPEC establish quiescent intracellular reservoirs that may lead to antibiotic tolerance and recurrent UTIs. Here, we demonstrate using an <i>in vitro</i> system that quiescent UPEC cells are tolerant to ampicillin and have decreased metabolism characterized by succinyl-CoA limitation. We identify the global regulator integration host factor complex and the cell division protein ZapE as critical modifiers of quiescence and antibiotic tolerance. Finally, we show that ZapE interacts with components of both the cell division machinery and the tricarboxylic acid cycle, and this interaction is conserved in non-pathogenic <i>E. coli</i>, establishing a novel link between cell division and metabolism.</p>","PeriodicalId":15107,"journal":{"name":"Journal of Bacteriology","volume":" ","pages":"e0016224"},"PeriodicalIF":2.7,"publicationDate":"2024-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11332148/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141175374","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":"Identification and characterization of zinc importers in <i>Corynebacterium diphtheriae</i>.","authors":"Eric D Peng, Lindsey R Lyman, Michael P Schmitt","doi":"10.1128/jb.00124-24","DOIUrl":"10.1128/jb.00124-24","url":null,"abstract":"<p><p><i>Corynebacterium diphtheriae</i> is the causative agent of diphtheria, a severe respiratory disease in humans. <i>C. diphtheriae</i> colonizes the human upper respiratory tract, where it acquires zinc, an essential metal required for survival in the host. While the mechanisms for zinc transport by <i>C. diphtheriae</i> are not well characterized, four putative zinc ABC-type transporter loci were recently identified in strain 1737: <i>iutABCD/E</i> (<i>iut</i>), <i>znuACB</i> (<i>znu</i>), <i>nikABCD1</i> (<i>nik1</i>), and <i>nikABCD2</i> (<i>nik2</i>). A mutant deleted for all four loci (Δ4) exhibited similar growth to that of the wild-type strain in a zinc-limited medium, suggesting there are additional zinc transporters. Two additional gene loci predicted to be associated with metal import, <i>mntABCD</i> (<i>mnt</i>) and <i>sidAB</i> (<i>sid</i>)<i>,</i> were deleted in the Δ4 mutant to construct a new mutant designated Δ6. The <i>C. diphtheriae</i> Δ6 mutant exhibited significantly reduced growth under zinc limitation relative to the wild type, suggesting a deficiency in zinc acquisition. Strains retaining the <i>iut</i>, <i>znu</i>, <i>mnt,</i> or <i>sid</i> loci grew to near-wild-type levels in the absence of the other five loci, indicating that each of these transporters may be involved in zinc uptake. Plasmid complementation with cloned <i>iut</i>, <i>znu</i>, <i>mnt</i>, or <i>nik1</i> loci also enhanced the growth of the Δ6 mutant. Quantification of intracellular zinc content by inductively coupled plasma mass spectrometry was consistent with reduced zinc uptake by Δ6 relative to the wild type and further supports a zinc uptake function for the transporters encoded by <i>iut</i>, <i>znu</i>, and <i>mnt</i>. This study demonstrates that <i>C. diphtheriae</i> zinc transport is complex and involves multiple zinc uptake systems.IMPORTANCEZinc is a critical nutrient for all forms of life, including human bacterial pathogens. Thus, the tools that bacteria use to acquire zinc from host sources are crucial for pathogenesis. While potential candidates for zinc importers have been identified in <i>Corynebacterium diphtheriae</i> from gene expression studies, to date, no study has clearly demonstrated this function for any of the putative transporters. We show that <i>C. diphtheriae</i> encodes at least six loci associated with zinc import, underscoring the extent of redundancy for zinc acquisition. Furthermore, we provide evidence that a previously studied manganese-regulated importer can also function in zinc import. This study builds upon our knowledge of bacterial zinc transport mechanisms and identifies potential targets for future diphtheria vaccine candidates.</p>","PeriodicalId":15107,"journal":{"name":"Journal of Bacteriology","volume":" ","pages":"e0012424"},"PeriodicalIF":2.7,"publicationDate":"2024-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11332173/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141161798","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":"Intrinsic and extrinsic determinants of conditional localization of Mms6 to magnetosome organelles in <i>Magnetospirillum magneticum</i> AMB-1.","authors":"Carson D Bickley, Juan Wan, Arash Komeili","doi":"10.1128/jb.00008-24","DOIUrl":"10.1128/jb.00008-24","url":null,"abstract":"<p><p>Magnetotactic bacteria are a diverse group of microbes that use magnetic particles housed within intracellular lipid-bounded magnetosome organelles to guide navigation along geomagnetic fields. The development of magnetosomes and their magnetic crystals in <i>Magnetospirillum magneticum</i> AMB-1 requires the coordinated action of numerous proteins. Most proteins are thought to localize to magnetosomes during the initial stages of organelle biogenesis, regardless of environmental conditions. However, the magnetite-shaping protein Mms6 is only found in magnetosomes that contain magnetic particles, suggesting that it might conditionally localize after the formation of magnetosome membranes. The mechanisms for this unusual mode of localization to magnetosomes are unclear. Here, using pulse-chase labeling, we show that Mms6 translated under non-biomineralization conditions translocates to pre-formed magnetosomes when cells are shifted to biomineralizing conditions. Genes essential for magnetite production, namely <i>mamE, mamM,</i> and <i>mamO,</i> are necessary for Mms6 localization, whereas <i>mamN</i> inhibits Mms6 localization. MamD localization was also investigated and found to be controlled by similar cellular factors. The membrane localization of Mms6 is dependent on a glycine-leucine repeat region, while the N-terminal domain of Mms6 is necessary for retention in the cytosol and impacts conditional localization to magnetosomes. The N-terminal domain is also sufficient to impart conditional magnetosome localization to MmsF, altering its native constitutive magnetosome localization. Our work illuminates an alternative mode of protein localization to magnetosomes in which Mms6 and MamD are excluded from magnetosomes by MamN until biomineralization initiates, whereupon they translocate into magnetosome membranes to control the development of growing magnetite crystals.IMPORTANCEMagnetotactic bacteria (MTB) are a diverse group of bacteria that form magnetic nanoparticles surrounded by membranous organelles. MTB are widespread and serve as a model for bacterial organelle formation and biomineralization. Magnetosomes require a specific cohort of proteins to enable magnetite formation, but how those proteins are localized to magnetosome membranes is unclear. Here, we investigate protein localization using pulse-chase microscopy and find a system of protein coordination dependent on biomineralization-permissible conditions. In addition, our findings highlight a protein domain that alters the localization behavior of magnetosome proteins. Utilization of this protein domain may provide a synthetic route for conditional functionalization of magnetosomes for biotechnological applications.</p>","PeriodicalId":15107,"journal":{"name":"Journal of Bacteriology","volume":" ","pages":"e0000824"},"PeriodicalIF":2.7,"publicationDate":"2024-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11332177/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141179671","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":"Prevalence of Slam-dependent hemophilins in Gram-negative bacteria.","authors":"Hyejin Esther Shin, Chuxi Pan, David M Curran, Thomas J Bateman, Derrick H Y Chong, Dixon Ng, Megha Shah, Trevor F Moraes","doi":"10.1128/jb.00027-24","DOIUrl":"10.1128/jb.00027-24","url":null,"abstract":"<p><p>Iron acquisition systems are crucial for pathogen growth and survival in iron-limiting host environments. To overcome nutritional immunity, bacterial pathogens evolved to use diverse mechanisms to acquire iron. Here, we examine a heme acquisition system that utilizes hemophores called hemophilins which are also referred to as HphAs in several Gram-negative bacteria. In this study, we report three new HphA structures from <i>Stenotrophomonas maltophilia</i>, <i>Vibrio harveyi</i>, and <i>Haemophilus parainfluenzae</i>. Structural determination of HphAs revealed an N-terminal clamp-like domain that binds heme and a C-terminal eight-stranded β-barrel domain that shares the same architecture as the Slam-dependent Neisserial surface lipoproteins. The genetic organization of HphAs consists of genes encoding a Slam homolog and a TonB-dependent receptor (TBDR). We investigated the Slam-HphA system in the native organism or the reconstituted system in <i>Escherichia coli</i> cells and found that the efficient secretion of HphA depends on Slam. The TBDR also played an important role in heme uptake and conferred specificity for its cognate HphA. Furthermore, bioinformatic analysis of HphA homologs revealed that HphAs are conserved in the alpha, beta, and gammaproteobacteria. Together, these results show that the Slam-dependent HphA-type hemophores are prevalent in Gram-negative bacteria and further expand the role of Slams in transporting soluble proteins.</p><p><strong>Importance: </strong>This paper describes the structure and function of a family of Slam (Type IX secretion System) secreted hemophores that bacteria use to uptake heme (iron) while establishing an infection. Using structure-based bioinformatics analysis to define the diversity and prevalence of this heme acquisition pathway, we discovered that a large portion of gammaproteobacterial harbors this system. As organisms, including <i>Acinetobacter baumannii</i>, utilize this system to facilitate survival during host invasion, the identification of this heme acquisition system in bacteria species is valuable information and may represent a target for antimicrobials.</p>","PeriodicalId":15107,"journal":{"name":"Journal of Bacteriology","volume":" ","pages":"e0002724"},"PeriodicalIF":2.7,"publicationDate":"2024-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11332172/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141179675","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 <i>Bacillus subtilis yqgC-sodA</i> operon protects magnesium-dependent enzymes by supporting manganese efflux.","authors":"Ankita J Sachla, Vijay Soni, Miguel Piñeros, Yuanchan Luo, Janice J Im, Kyu Y Rhee, John D Helmann","doi":"10.1128/jb.00052-24","DOIUrl":"10.1128/jb.00052-24","url":null,"abstract":"<p><p>Microbes encounter a myriad of stresses during their life cycle. Dysregulation of metal ion homeostasis is increasingly recognized as a key factor in host-microbe interactions. Bacterial metal ion homeostasis is tightly regulated by dedicated metalloregulators that control uptake, sequestration, trafficking, and efflux. Here, we demonstrate that deletion of the <i>Bacillus subtilis yqgC-sodA</i> (YS) complex operon, but not deletion of the individual genes, causes hypersensitivity to manganese (Mn). YqgC is an integral membrane protein of unknown function, and SodA is a Mn-dependent superoxide dismutase (MnSOD). The YS strain has reduced expression of two Mn efflux proteins, MneP and MneS, consistent with the observed Mn sensitivity. The YS strain accumulated high levels of Mn, had increased reactive radical species (RRS), and had broad metabolic alterations that can be partially explained by the inhibition of Mg-dependent enzymes. Although the YS operon deletion strain and an efflux-deficient <i>mneP mneS</i> double mutant both accumulate Mn and have similar metabolic perturbations, they also display phenotypic differences. Several mutations that suppressed Mn intoxication of the <i>mneP mneS</i> efflux mutant did not benefit the YS mutant. Further, Mn intoxication in the YS mutant, but not the <i>mneP mneS</i> strain, was alleviated by expression of Mg-dependent, chorismate-utilizing enzymes of the <u>m</u>enaquinone, <u>s</u>iderophore, and <u>t</u>ryptophan (MST) family. Therefore, despite their phenotypic similarities, the Mn sensitivity in the <i>mneP mneS</i> and the YS deletion mutants results from distinct enzymatic vulnerabilities.IMPORTANCEBacteria require multiple trace metal ions for survival. Metal homeostasis relies on the tightly regulated expression of metal uptake, storage, and efflux proteins. Metal intoxication occurs when metal homeostasis is perturbed and often results from enzyme mis-metalation. In <i>Bacillus subtilis</i>, Mn-dependent superoxide dismutase (MnSOD) is the most abundant Mn-containing protein and is important for oxidative stress resistance. Here, we report novel roles for MnSOD and a co-regulated membrane protein, YqgC, in Mn homeostasis. Loss of both MnSOD and YqgC (but not the individual proteins) prevents the efficient expression of Mn efflux proteins and leads to a large-scale perturbation of the metabolome due to inhibition of Mg-dependent enzymes, including key chorismate-utilizing MST (menaquinone, siderophore, and tryptophan) family enzymes.</p>","PeriodicalId":15107,"journal":{"name":"Journal of Bacteriology","volume":" ","pages":"e0005224"},"PeriodicalIF":2.7,"publicationDate":"2024-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11332163/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141179678","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":"Group B <i>Streptococcus</i> transcriptome when interacting with brain endothelial cells.","authors":"Nadine Vollmuth, Bailey E Bridgers, Madelyn L Armstrong, Jacob F Wood, Abigail R Gildea, Eric R Espinal, Thomas A Hooven, Giulia Barbieri, Alexander J Westermann, Till Sauerwein, Konrad U Foerstner, Alexandra Schubert-Unkmeir, Brandon J Kim","doi":"10.1128/jb.00087-24","DOIUrl":"10.1128/jb.00087-24","url":null,"abstract":"<p><p>Bacterial meningitis is a life-threatening infection of the central nervous system (CNS) that occurs when bacteria are able to cross the blood-brain barrier (BBB) or the meningeal-cerebrospinal fluid barrier (mBCSFB). The BBB and mBCSFB comprise highly specialized brain endothelial cells (BECs) that typically restrict pathogen entry. Group B <i>Streptococcus</i> (GBS or <i>Streptococcus agalactiae</i>) is the leading cause of neonatal meningitis. Until recently, identification of GBS virulence factors has relied on genetic screening approaches. Instead, we here conducted RNA-seq analysis on GBS when interacting with induced pluripotent stem cell-derived BECs (iBECs) to pinpoint virulence-associated genes. Of the 2,068 annotated protein-coding genes of GBS, 430 transcripts displayed significant changes in expression after interacting with BECs. Notably, we found that the majority of differentially expressed GBS transcripts were downregulated (360 genes) during infection of iBECs. Interestingly, <i>codY</i>, encoding a pleiotropic transcriptional repressor in low-G + C Gram-positive bacteria, was identified as being highly downregulated. We conducted qPCR to confirm the <i>codY</i> downregulation observed via RNA-seq during the GBS-iBEC interaction and obtained <i>codY</i> mutants in three different GBS background parental strains. As anticipated from the RNA-seq results, the [Formula: see text]<i>codY</i> strains were more adherent and invasive in two <i>in vitro</i> BEC models. Together, this demonstrates the utility of RNA-seq during the BEC interaction to identify GBS virulence modulators.</p><p><strong>Importance: </strong>Group B <i>Streptococcus</i> (GBS) meningitis remains the leading cause of neonatal meningitis. Research work has identified surface factors and two-component systems that contribute to GBS disruption of the blood-brain barrier (BBB). These discoveries often relied on genetic screening approaches. Here, we provide transcriptomic data describing how GBS changes its transcriptome when interacting with brain endothelial cells. Additionally, we have phenotypically validated these data by obtaining mutants of a select regulator that is highly down-regulated during infection and testing on our BBB model. This work provides the research field with a validated data set that can provide an insight into potential pathways that GBS requires to interact with the BBB and open the door to new discoveries.</p>","PeriodicalId":15107,"journal":{"name":"Journal of Bacteriology","volume":" ","pages":"e0008724"},"PeriodicalIF":2.7,"publicationDate":"2024-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11332166/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141070986","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":"T6SS nuclease effectors in <i>Pseudomonas syringae</i> act as potent antimicrobials in interbacterial competition.","authors":"Xun Yu, Yubo Yan, Jie Zeng, Yongxuan Liu, Xiaowen Sun, Zhiyong Wang, Lin Li","doi":"10.1128/jb.00273-23","DOIUrl":"10.1128/jb.00273-23","url":null,"abstract":"<p><p>Type VI secretion system (T6SS) is a potent weapon employed by various <i>Pseudomonas</i> species to compete with neighboring microorganisms for limited nutrients and ecological niches. However, the involvement of T6SS effectors in interbacterial competition within the phytopathogen <i>Pseudomonas syringae</i> remains unknown. In this study, we examined two T6SS clusters in a wild-type <i>P. syringae</i> MB03 and verified the involvement of one cluster, namely, T6SS-1, in interbacterial competition. Additionally, our results showed that two T6SS DNase effectors, specifically Tde1 and Tde4, effectively outcompeted antagonistic bacteria, with Tde4 playing a prominent role. Furthermore, we found several cognate immunity proteins, including Tde1i^a, Tde1i^b, and Tde4i, which are located in the downstream loci of their corresponding effector protein genes and worked synergistically to protect MB03 cells from self-intoxication. Moreover, expression of either Tde1 or C-terminus of Tde4 in <i>Escherichia coli</i> cells induced DNA degradation and changes in cell morphology. Thus, our results provide new insights into the role of the T6SS effectors of <i>P. syringae</i> in the interbacterial competition in the natural environment.</p><p><strong>Importance: </strong>The phytopathogen <i>Pseudomonas syringae</i> employs an active type VI secretion system (T6SS) to outcompete other microorganisms in the natural environment, particularly during the epiphytic growth in the phyllosphere. By examining two T6SS clusters in <i>P. syringae</i> MB03, T6SS-1 is found to be effective in killing <i>Escherichia coli</i> cells. We highlight the excellent antibacterial effect of two T6SS DNase effectors, namely, Tde1 and Tde4. Both of them function as nuclease effectors, leading to DNA degradation and cell filamentation in prey cells, ultimately resulting in cell death. Our findings deepen our understanding of the T6SS effector repertoires used in <i>P. syringae</i> and will facilitate the development of effective antibacterial strategies.</p>","PeriodicalId":15107,"journal":{"name":"Journal of Bacteriology","volume":" ","pages":"e0027323"},"PeriodicalIF":2.7,"publicationDate":"2024-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11332151/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140876554","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}