Journal of Bacteriology最新文献

{"title":"Rv3400 is a phosphoglucomutase required for trehalose metabolism in <i>Mycobacterium tuberculosis</i>.","authors":"Yi Liu, Nadine Ruecker, Valwynne Faulkner, Kavitha Rachineni, Nada Al-Saffar, Elisabeth Oskoui, Larissa Zarate Garcia, Jessica Emma Rowley, Pablo Villacampa Teixeira, Tiago R D Costa, Eachan Johnson, Brian D Robertson, Sabine Ehrt, Gerald Larrouy-Maumus","doi":"10.1128/jb.00343-26","DOIUrl":"https://doi.org/10.1128/jb.00343-26","url":null,"abstract":"<p><p><i>Mycobacterium tuberculosis</i> (Mtb) causes over 1 million deaths from tuberculosis (TB) every year and remains a major burden on human health. Reducing the deadly impact of TB requires a better understanding of the strategies used by <i>M. tuberculosis</i> to adapt its metabolism, survive, and persist in the human host. Previous enzymological studies reported that the Mtb <i>rv3400</i> gene encodes a β-phosphoglucomutase; however, its role in <i>M. tuberculosis</i> metabolism had not been investigated. Here, we show that deletion of <i>rv3400</i> causes a 30-fold increase in β-D-glucose-1-phosphate, confirming its primary function as a β-phosphoglucomutase. Deletion of <i>rv3400</i> also causes a growth defect when trehalose is the sole carbon source. Targeted metabolomics revealed that metabolites associated with redox homeostasis, including ergothioneine, mycothiol, and mycothione, are decreased in the Mtb Δ<i>rv3400</i> strain compared with the wild type, indicating altered tolerance to redox stress. Consistent with this, the Δ<i>rv3400</i> strain showed increased susceptibility to oxidative stress induced by H₂O₂ and cumene hydroperoxide, conditions that Mtb encounters during infection. This work advances our understanding of trehalose metabolism in Mtb and suggests that Rv3400 may represent a target for the development of new antimicrobial therapies.</p><p><strong>Importance: </strong>Trehalose metabolism plays a cornerstone role in <i>Mycobacterium tuberculosis</i> physiology and virulence. A better understanding of the metabolism of this essential disaccharide is therefore required to develop new strategies to eradicate tuberculosis. Here, we characterize <i>M. tuberculosis</i> lacking the β-phosphoglucomutase encoded by <i>rv3400</i>. We show that deletion of <i>rv3400</i> leads to accumulation of β-D-glucose-1-phosphate, impaired growth when trehalose is used as the sole carbon source, and increased susceptibility to oxidative stress. Taken together, these data provide evidence that Rv3400 is required for optimal catabolism of trehalose.</p>","PeriodicalId":15107,"journal":{"name":"Journal of Bacteriology","volume":" ","pages":"e0034326"},"PeriodicalIF":3.8,"publicationDate":"2026-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148887708","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":"Importance of balanced intracellular formate levels for pH_i and CO₂ homeostases during mixed-acid fermentation.","authors":"Christopher Erdmann, Liana Vanyan, Karen Trchounian, R Gary Sawers","doi":"10.1128/jb.00356-26","DOIUrl":"https://doi.org/10.1128/jb.00356-26","url":null,"abstract":"<p><p>During mixed-acid fermentation, <i>Escherichia coli</i> metabolizes glucose to a mixture of acetate, ethanol, formate, lactate, and succinate, together with equimolar amounts of H₂ and CO₂. These gases are generated via the disproportionation of formate by formate hydrogenlyase (FHL-1). This reaction provides the cell with its only source of internally generated CO₂ for carboxylation reactions. Formate is produced by pyruvate formate-lyase (PflB), and its balanced level within the cell is maintained by the activities of PflB, FHL-1, and the bidirectional formate channel, FocA. A formate imbalance results when strains synthesize a FocA_N209 variant that continuously and efficiently exports formic acid. During fermentative growth, a FocA_N209-producing strain prematurely enters stationary phase and fails to synthesize FHL-1 due to intracellular formate insufficiency. Here, we show that intracellular pH (pH_i) of the mutant was increased relative to the parental strain, correlating with reduced ATP levels. Anaerobic growth could be partially restored by cultivation with bicarbonate; however, pH_i was lowered only marginally and ATP levels remained low. Determination of the fermentation-product profile revealed that the continuous loss of formate from the cell could not be compensated by bicarbonate supplementation. A severe limitation in both lactate and succinate production was also only partially rescued by bicarbonate. Increased ethanol production indicated that acetyl-CoA was sacrificed in the mutant to re-oxidize reduced pyridine nucleotides. These findings demonstrate that an imbalance in intracellular formate not only negatively impacts carboxylative metabolism but also remodels the spectrum of fermentation products to the detriment of the cell's energy metabolism and pH homeostasis.IMPORTANCEFormate is central to the fermentative metabolism of <i>Escherichia coli</i>. Balanced formate levels are required for DNA synthesis and for CO₂ generation by formate hydrogenlyase (FHL-1). An <i>E. coli</i> mutant synthesizing an FocA variant that irreversibly exports formate has a severe growth defect because it cannot make FHL-1, which severely restricts CO₂ and negatively impacts pH homeostasis by lowering ATP levels. We show, however, that impaired growth of the mutant can be only partially restored by supplying bicarbonate. The underlying cellular lack of formate cannot be fully compensated by bicarbonate because efficient pyruvate formate-lyase-dependent pyruvate cleavage remodels fermentation away from acetate and toward ethanol production, which ensures redox balance, but generates less ATP by substrate-level phosphorylation.</p>","PeriodicalId":15107,"journal":{"name":"Journal of Bacteriology","volume":" ","pages":"e0035626"},"PeriodicalIF":3.8,"publicationDate":"2026-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148887684","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":"Components of the Clp complex are required for sporangium formation and dehiscence in <i>Actinoplanes missouriensis</i>.","authors":"Ryota Suzuki, Manato Maruko, Remi Suzuki, Takeaki Tezuka, Yasuo Ohnishi","doi":"10.1128/jb.00308-26","DOIUrl":"https://doi.org/10.1128/jb.00308-26","url":null,"abstract":"<p><p>The actinomycete <i>Actinoplanes missouriensis</i> forms terminal sporangia that contain a few hundred spores. When immersed in water, the sporangium opens to release spores, which start swimming using flagella, via a process referred to as sporangium dehiscence. In this study, we conducted a functional analysis of genes encoding the components of the caseinolytic protease (Clp) complex, which comprises ATPase (chaperone) subunits (ClpX and ClpC) and proteolytic subunits (ClpP1-4). The <i>clpX</i> null mutant (Δ<i>clpX</i>) strain formed sporangia smaller than the wild-type strain. The small sporangia scarcely opened under conditions that induce sporangium dehiscence in the wild-type strain. Consistently, the number of released spores was three orders of magnitude lower in the Δ<i>clpX</i> strain than in the wild-type strain. S1 nuclease mapping determined two transcriptional start points of <i>clpX</i> (TSS_U and TSS_D for upstream and downstream, respectively). A housekeeping sigma factor-dependent promoter and a FliA-family sigma factor-dependent promoter were found upstream of TSS_U and TSS_D, respectively. A gene complementation test showed that apparently normal sporangium formation in the Δ<i>clpX</i> strain was restored by the introduction of <i>clpX</i> with either of the two promoters, whereas both promoters were required for sporangium dehiscence. Meanwhile, mutant strains that produced ClpC with T30S or I33F/L34F replacements, which presumably reduced their substrate-binding activity, produced sporangia with irregular shapes. Furthermore, gene disruption experiments of four putative proteolytic subunit genes indicated that <i>clpP3</i> is conditionally involved in sporangium dehiscence. We concluded that sporangium formation and dehiscence are regulated at the post-translational level via proteolysis by Clp complexes in <i>A. missouriensis</i>.</p><p><strong>Importance: </strong><i>Actinoplanes missouriensis</i> has a complex life cycle, in which the sporangium containing a few hundred flagellated spores is the most characteristic structure. Spores are released from sporangia via a process called sporangium dehiscence. We have revealed that sporangium formation and dehiscence are regulated by several transcriptional regulators; however, post-transcriptional regulation of sporangium formation and dehiscence remains unknown. In the present study, we revealed that two ATPase components of the Clp complex, ClpC and ClpX, and a proteolytic component, ClpP3, are involved in sporangium formation and/or dehiscence. This study indicates that in addition to transcriptional regulation, proteolysis regulated by Clp complexes is another crucial factor in the morphological development of <i>A. missouriensis</i>.</p>","PeriodicalId":15107,"journal":{"name":"Journal of Bacteriology","volume":" ","pages":"e0030826"},"PeriodicalIF":3.8,"publicationDate":"2026-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148880523","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":"Defining the order of assembly of the <i>Clostridioides difficile</i> divisome complex.","authors":"Gregory A Harrison, Pola Kuhn, Shailab Shrestha, Paula Caballero Blanco, Larissa Havey, Aimee Shen","doi":"10.1128/jb.00032-26","DOIUrl":"10.1128/jb.00032-26","url":null,"abstract":"<p><p>Cell division is the ancient pathway by which bacteria synthesize a septum of peptidoglycan, dividing the cell into two. Although all walled bacteria were previously thought to use FtsW-FtsI orthologs to synthesize septal peptidoglycan during division, we recently discovered that the major pathogen <i>Clostridioides difficile</i> is missing FtsW-FtsI and instead relies on the activity of the bifunctional Class A penicillin-binding protein (PBP) called PBP1 to synthesize septal peptidoglycan during vegetative division. Furthermore, <i>C. difficile</i> either does not encode or require the majority of canonical divisome proteins described in model bacteria aside from the divisome protein orthologs FtsZ, SepF, and ZapA. Indeed, unlike model systems, SepF and ZapA are essential in <i>C. difficile</i>, suggesting that they have evolved to have a critical function in cell division without the redundant mechanisms present in model organisms. Thus, <i>C. difficile</i> uses a fundamentally different division mechanism compared to previously studied bacteria. To understand how this unusual complex is assembled in <i>C. difficile</i>, we combine CRISPR interference-based knockdowns with fluorescent fusions to determine that the hierarchical order of assembly occurs in three phases: (i) FtsZ/ZapA, (ii) SepF, and (iii) PBP1. We further investigate the order of assembly of several non-essential mid-cell localizing proteins and discover that MldA, MldC, DivIVA, FtsK, and PBP3 depend on FtsZ, SepF, and PBP1 for localization, whereas MldB localizes independently of SepF and PBP1. Our work provides a model for divisome assembly in <i>C. difficile</i> and validates genetic and cytological tools that can be used to mechanistically dissect this pathway in the future.IMPORTANCEBacterial cell division has been extensively studied in model systems, but little is known about how this essential process occurs in the clinically important pathogen <i>Clostridioides difficile</i>. Studies in model systems have shown that cell division is carried out by a large multi-protein complex called the \"divisome.\" While components of the divisome are widely conserved and can be traced back to the last bacterial common ancestor billions of years ago, <i>C. difficile</i> uses a unique mechanism of division that is independent of most canonical divisome genes. In the current study, we characterize the core, essential divisome comprised of FtsZ, ZapA, SepF, and PBP1, and build a model for the order of assembly of this unusual divisome complex.</p>","PeriodicalId":15107,"journal":{"name":"Journal of Bacteriology","volume":" ","pages":"e0003226"},"PeriodicalIF":3.8,"publicationDate":"2026-08-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148828554","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":"Ribonucleotide reductase repression: a mutational study of NrdR-binding motifs.","authors":"Saher Shahid, Daniel Lundin, Inna Rozman Grinberg, Britt-Marie Sjöberg","doi":"10.1128/jb.00274-26","DOIUrl":"https://doi.org/10.1128/jb.00274-26","url":null,"abstract":"<p><p>The prevalent transcriptional repressor NrdR binds to highly conserved sequences in the promoter regions of prokaryotic operons encoding the essential enzyme ribonucleotide reductase. The NrdR-binding sites consist of two partially palindromic 16 bp sequences (NrdR boxes) separated by a 15-16 bp linker sequence. We have assessed the requirement of both boxes for binding, the propensity of different NrdRs to bind to heterologous binding sites, and that the linker sequence is only limited to length and not sequence conservation. As we have observed several deviations from the conserved sequences of the NrdR boxes, we have tested the conservation requirements of individual base pairs in the NrdR boxes using a synthetic DNA fragment (Synt DNA) to which the NrdR proteins from the actinomycete <i>Streptomyces coelicolor</i> and the gammaproteobacterium <i>Escherichia coli</i> bind equally well as to their homologous binding sites. By introducing isolated mutations to Synt DNA and testing the binding capacity of NrdR from <i>S. coelicolor</i> and <i>E. coli</i>, we expand our understanding of what criteria are needed to build a functional binding site for the NrdR repressor. Our results enable more precise identification of NrdR-binding sites across bacterial genomes, which can be used to explore NrdR and its regulons as potential targets for the development of novel antimicrobials.IMPORTANCEThe transcriptional repressor NrdR is strictly prokaryotic, occurring in 77% of bacterial genomes, and 22% of archaeal genomes. It binds to highly conserved sequences in the promoter regions of the genes encoding the essential enzyme ribonucleotide reductase that provides cells with <i>de novo</i> building blocks for DNA synthesis. Repression of ribonucleotide reductase expression leads to a lack of replication and cell proliferation. In this report, we have characterized in detail the generality of the partially palindromic sequences constituting the NrdR-binding site. As NrdR controls the sole <i>de novo</i> pathways for production of DNA building blocks in bacteria and not in eukaryotes, our results will facilitate screens for novel antimicrobials utilizing the NrdR protein and its homologous regulons in pathogenic bacteria.</p>","PeriodicalId":15107,"journal":{"name":"Journal of Bacteriology","volume":" ","pages":"e0027426"},"PeriodicalIF":3.8,"publicationDate":"2026-08-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148828650","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 <i>Staphylococcus aureus</i>, MbcS is a refunctionalized acyl-CoA synthetase that confers a fitness advantage during intra-species competition.","authors":"Marcelle C Dos Santos Ferreira, Timothy G Stephens, Shaun R Brinsmade","doi":"10.1128/jb.00185-26","DOIUrl":"10.1128/jb.00185-26","url":null,"abstract":"<p><p><i>Staphylococcus aureus</i> is one of the most frequently co-isolated pathogens in polymicrobial infections, where interspecies interactions contribute to enhanced virulence, persistence, and antimicrobial tolerance. Nutrient availability plays a central role in these interactions as microorganisms compete for resources to sustain essential cellular processes. For instance, branched-chain amino acids (BCAAs) are critical for protein synthesis, and valine synthesis pathway precursors are essential for energy production. In <i>S. aureus</i>, BCAAs are also the precursors for branched-chain fatty acids (BCFAs), the dominant fatty acids in the <i>S. aureus</i> membrane. We previously identified a second pathway that uses branched-chain carboxylic acids (BCCAs) and the high-affinity acyl-CoA synthetase MbcS to catalyze the formation of primers for BCFA synthesis. However, the physiological role of this pathway and the conditions triggering its activation remain unclear. Here, we show that <i>mbcS</i> is restricted to <i>S. aureus</i> and closely related human-associated staphylococci. Phylogenetic analyses suggest that MbcS arose from a refunctionalization event and represents a non-orthologous replacement for the phosphotransbutyrylase (Ptb) and butyrate kinase (Buk) enzymes. Consistent with this model, Ptb and Buk from <i>Staphylococcus pseudintermedius</i> catalyze the formation of branched-chain acyl-CoAs from BCCAs, but only at high substrate concentrations. We further show that <i>mbcS</i> expression is upregulated in a CodY-deficient strain, implicating this pathway in BCAA-limited conditions. In support, we show that MbcS is required for optimal fitness during intra-species competition. Together, our findings support a model in which the MbcS-dependent pathway enables <i>S. aureus</i> to scavenge BCFA precursors under nutrient-limited conditions, providing a competitive advantage in polymicrobial environments.</p><p><strong>Importance: </strong><i>Staphylococcus aureus</i> is a major contributor to polymicrobial infections, where competition for nutrients can influence bacterial physiology and survival. A deeper understanding of how <i>S. aureus</i> adapts to nutrient limitation is therefore essential to explain its success as a human pathogen. In <i>S. aureus</i>, the acyl-CoA synthetase MbcS supports branched-chain fatty acid (BCFA) synthesis from branched-chain amino acid (BCAA)-derived carboxylic acids and aldehydes, which are released into the environment as by-products of bacterial metabolism. Herein, we provide evidence that <i>S. aureus</i> acquired the acyl-CoA synthetase MbcS as an adaptive trait. This metabolic innovation allows this bacterium to maintain membrane homeostasis under nutrient limitation and compete against neighboring bacteria. Our findings highlight an adaptive strategy that may contribute to the persistence of <i>S. aureus</i> in polymicrobial infections.</p>","PeriodicalId":15107,"journal":{"name":"Journal of Bacteriology","volume":" ","pages":"e0018526"},"PeriodicalIF":3.8,"publicationDate":"2026-08-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148828745","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":"Correction for Sen et al., \"Distinct motors, shared mechanics: unifying principles of microbial gliding\".","authors":"Samyabrata Sen, E C Henderson, Ferran Garcia-Pichel, Mohammed Kaplan, Abhishek Shrivastava","doi":"10.1128/jb.00215-26","DOIUrl":"https://doi.org/10.1128/jb.00215-26","url":null,"abstract":"","PeriodicalId":15107,"journal":{"name":"Journal of Bacteriology","volume":" ","pages":"e0021526"},"PeriodicalIF":3.8,"publicationDate":"2026-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148818509","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":"Correction for Ellis et al., \"Glutathione impacts Hfq condensation in nitrogen-starved <i>Escherichia coli</i>\".","authors":"Harriet R Ellis, Volker Behrends, Gerald Larrouy-Maumus, Josh McQuail, Sivaramesh Wigneshweraraj","doi":"10.1128/jb.00294-26","DOIUrl":"https://doi.org/10.1128/jb.00294-26","url":null,"abstract":"","PeriodicalId":15107,"journal":{"name":"Journal of Bacteriology","volume":" ","pages":"e0029426"},"PeriodicalIF":3.8,"publicationDate":"2026-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148818435","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":"<i>Aeromonas veronii</i> biotype sobria serine protease activates aerolysin and cleaves EpCAM to breach the epithelial barrier.","authors":"Hidetomo Kobayashi, Soshi Seike, Eizo Takahashi, Keinosuke Okamoto, Hiroyasu Yamanaka","doi":"10.1128/jb.00141-26","DOIUrl":"10.1128/jb.00141-26","url":null,"abstract":"<p><p>Infections by <i>Aeromonas</i> can rapidly progress from mucosal colonization to invasive disease, but how these bacteria efficiently breach epithelial barriers is unclear. Here, we define a coordinated two-component virulence strategy in <i>Aeromonas veronii</i> biotype sobria (<i>A. veronii</i> sobria) involving a secreted serine protease (ASP) and aerolysin. In polarized T84 monolayers, wild-type infection caused rapid transepithelial electrical resistance (TEER) loss and degradation of junctional/adhesion proteins. An ASP-deficient strain exhibited delayed barrier collapse with reduced cleavage of ZO-1/2/3 and EpCAM, and purified ASP restored these effects, indicating ASP is required but alone insufficient for full disruption. A transposon screen identified aerolysin and secretion-related genes as key contributors to junctional damage. Mechanistically, ASP directly converted recombinant pro-aerolysin into a hemolytically active toxin <i>in vitro</i>, linking protease activity to toxin maturation. Functionally, ASP and aerolysin synergized to promote bacterial translocation across epithelial monolayers with marked sequence dependence; pro-aerolysin pretreatment enhanced ASP-mediated degradation of ZO proteins, claudin-7, and EpCAM. ASP further cleaved EpCAM at multiple extracellular sites, compromising adhesion and junctional homeostasis. Together, these findings establish an ASP-aerolysin pathway that couples toxin activation with junctional proteolysis to drive structural epithelial breaches.IMPORTANCE<i>Aeromonas</i> infections can rapidly progress from intestinal colonization to invasive disease, yet the molecular steps enabling epithelial breach are unclear. We show that <i>Aeromonas veronii</i> sobria uses a coordinated two-factor pathway in which <i>Aeromonas</i> serine protease (ASP) both activates the pore-forming toxin aerolysin and directly cleaves key junctional/adhesion proteins, including ZO-1/2/3 and EpCAM. Aerolysin primes cells for enhanced ASP-mediated proteolysis in an order-dependent manner, converting TEER loss into a physical barrier rupture that permits massive bacterial translocation. Targeting ASP-aerolysin cooperation may provide a rational anti-virulence strategy.</p>","PeriodicalId":15107,"journal":{"name":"Journal of Bacteriology","volume":" ","pages":"e0014126"},"PeriodicalIF":3.8,"publicationDate":"2026-08-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13492141/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148421491","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":"Type VIIb secretion systems in Lactobacillales: insights from streptococci and enterococci.","authors":"Caitlin S Wiafe-Kwakye, Abigail E Glenn, Brady L Spencer","doi":"10.1128/jb.00236-26","DOIUrl":"10.1128/jb.00236-26","url":null,"abstract":"<p><p>The type VII secretion system (T7SS) is an ATPase-powered molecular machine encoded by Actinomycetota (T7SSa) and Bacillota (T7SSb) that exports small alpha-helical effectors with functions in interbacterial competition, host colonization, and virulence. While T7SSb has been well characterized in <i>Staphylococcus aureus</i> and <i>Bacillus subtilis</i>, its presence and function within the order Lactobacillales have only been thoroughly investigated within the past decade. Experimental evidence for T7SSb function has now been established in select <i>Streptococcus</i> and <i>Enterococcus</i> species. Here, we review the current understanding of T7SSb in these genera, covering core machinery and secreted substrates, including LXG toxins and WXG100 proteins. We discuss the roles of T7SSb during interbacterial antagonism and host-pathogen interactions, including contributions to cytotoxicity and virulence, as well as mucosal colonization and persistence. We further review known regulators of the T7SSb and evaluate the ecological significance of T7SSb-mediated competition for microbial community stability. Finally, we highlight outstanding questions in the field, including mechanisms of effector delivery, structural determination of the apparatus, impact of effectors on host immunity, and potential therapeutic targeting of T7SSb components.</p>","PeriodicalId":15107,"journal":{"name":"Journal of Bacteriology","volume":" ","pages":"e0023626"},"PeriodicalIF":3.8,"publicationDate":"2026-08-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13492133/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148520342","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}