Journal of Bacteriology最新文献

{"title":"Genetic and biochemical analyses reveal direct interactions between LitR and genes important for <i>Vibrio fischeri</i> physiology, including biofilm production.","authors":"Brittany L Fung, Chase Mullins, Douglas B Rusch, Elizabeth G Musto, Julia C van Kessel, Karen L Visick","doi":"10.1128/jb.00042-25","DOIUrl":"https://doi.org/10.1128/jb.00042-25","url":null,"abstract":"<p><p>Bacteria can link gene expression to population density to promote group behaviors using quorum sensing. Quorum sensing controls a multitude of bacterial processes, such as virulence, motility, and biofilm formation. In <i>Vibrio fischeri</i>, the quorum-sensing-dependent transcription factor LitR inhibits biofilm formation. A previous study showed that LitR inhibits transcription (~1.4-fold) of the <i>bcs</i> locus, which comprises the genes responsible for producing the cellulose polysaccharide. However, beyond that, the mechanism of LitR-mediated inhibition of biofilm formation was unknown. Here, we find that LitR transcriptionally activates <i>pdeV</i>, which encodes a c-di-GMP phosphodiesterase that indirectly promotes cleavage of the large adhesive protein LapV from the surface of <i>V. fischeri</i>, leading to biofilm dispersal. LitR also induces transcription of the gene for sensor kinase VF_A1016, which we determined to be important for biofilm inhibition. Like the loss of LitR, the loss of VF_A1016 increased <i>bcs</i> transcription (~1.6-fold). Through chromatin immunoprecipitation sequencing (ChIP-seq), we found that LitR directly binds to the <i>VF_A1016</i> and <i>pdeV</i> regulatory region. In total, we identified 147 LitR-binding sites in the genome and confirmed transcriptional control over a subset of these putative regulatory targets. Specifically, we determined that LitR induces transcription of the genes encoding the diguanylate cyclase VF_1200 and the glyoxylate shunt protein AceB and inhibits expression of the putative transcription factor TfoY. These data expand our understanding of LitR-mediated regulation of genes involved in biofilm formation and the physiology of <i>V. fischeri</i>.IMPORTANCEBacteria can coordinate their behaviors on a population level using quorum sensing, a process that results in altered gene regulation. In <i>Vibrio fischeri</i>, the quorum-sensing-regulated transcription factor LitR inhibits the formation of biofilms, communities of attached and protected bacteria, by diminishing the production of cellulose. Here, we determined that LitR controls additional known or putative biofilm factors. We also identified other possible targets of LitR regulation by high-throughput chromatin immunoprecipitation sequencing. This work furthers our understanding of the established connection between quorum sensing and biofilm formation in <i>V. fischeri</i> strain ES114. These findings also have the potential to translate to known pathways in other <i>Vibrios</i> where quorum sensing and biofilm production are linked.</p>","PeriodicalId":15107,"journal":{"name":"Journal of Bacteriology","volume":" ","pages":"e0004225"},"PeriodicalIF":3.0,"publicationDate":"2025-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144760135","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":"Extracellular defense of bacteria against antimicrobial peptides.","authors":"Osmel Fleitas, Eria A Rebollar, Víctor H Bustamante","doi":"10.1128/jb.00166-25","DOIUrl":"https://doi.org/10.1128/jb.00166-25","url":null,"abstract":"<p><p>Antimicrobial peptides (AMPs) are short chains of amino acids naturally produced by all kingdoms of life, which exhibit broad-spectrum activity against bacteria, fungi, and viruses and thus play a crucial defense role in organisms. Unlike conventional antibiotics, AMPs are less prone to induce bacterial resistance since they can act on multiple targets, mainly affecting cell membranes. Thus, AMPs are considered promising antibiotic agents for medical applications. However, bacteria have developed different mechanisms to resist the action of AMPs, which operate at the extracellular, surface, and intracellular levels. Extracellular defense against AMPs is mediated by an arsenal of molecules or cell-derived particles or structures that are secreted and constitute the bacterial releasome. The bacterial releasome-associated factors can sequester, degrade, or chemically modify AMPs, thus providing individual and collective bacterial defense against AMPs. This minireview describes how diverse and impressive the releasome mechanisms mediating AMPs resistance are as a first line of defense.</p>","PeriodicalId":15107,"journal":{"name":"Journal of Bacteriology","volume":" ","pages":"e0016625"},"PeriodicalIF":3.0,"publicationDate":"2025-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144760134","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":"Bacterial two-hybrid systems evolved: innovations for protein-protein interaction research.","authors":"Rebecca M Richardson, Steven M Pascal","doi":"10.1128/jb.00129-25","DOIUrl":"https://doi.org/10.1128/jb.00129-25","url":null,"abstract":"<p><p>Bacterial two-hybrid (B2H) systems offer a versatile platform for detecting protein-protein interactions (PPIs) <i>in vivo</i>. Originally developed to study bacterial transcriptional regulators, these systems have evolved to support a wide range of applications, including interaction mapping, domain analysis, and high-throughput screening. This review surveys the development and expansion of B2H systems across diverse biological contexts. We highlight technical considerations, platform-specific innovations, and recent adaptations that extend the utility of B2H systems in both prokaryotic and eukaryotic protein interaction research environments. By comparing different B2H variants and discussing their integration with complementary approaches, we provide a framework for leveraging these systems in modern PPI discovery.</p>","PeriodicalId":15107,"journal":{"name":"Journal of Bacteriology","volume":" ","pages":"e0012925"},"PeriodicalIF":3.0,"publicationDate":"2025-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144760122","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":"Quorum sensing regulation by the nitrogen phosphotransferase system in <i>Pseudomonas aeruginosa</i>.","authors":"Samalee Banerjee, Nicole E Smalley, Pradtahna Saenjamsai, Anthony R Fehr, Ajai A Dandekar, Matthew T Cabeen, Josephine R Chandler","doi":"10.1128/jb.00048-25","DOIUrl":"https://doi.org/10.1128/jb.00048-25","url":null,"abstract":"<p><p>In the opportunistic pathogen <i>Pseudomonas aeruginosa</i>, the nitrogen-related phosphotransferase system (PTS^Ntr) influences multiple virulence behaviors. The PTS^Ntr is comprised of three enzymes: first PtsP, then the PtsO phosphocarrier, and the final PtsN phosphoacceptor. We previously showed that <i>ptsP</i> inactivation enhances LasI-LasR quorum sensing, a system by which <i>P. aeruginosa</i> regulates genes in response to population density. LasI synthesizes a diffusible autoinducer that binds and activates the LasR receptor, which activates a feedback loop by increasing <i>lasI</i> expression. In this study, we examined the impact of the PTS^Ntr on quorum sensing. Disruption of <i>ptsP</i> increased the expression of some, but not all, tested quorum-controlled genes, including <i>lasI, phzM</i> (pyocyanin biosynthesis), <i>hcnA</i> (hydrogen cyanide biosynthesis), and, to a lesser extent, <i>rsaL</i> (quorum sensing regulator). Expression of these genes remained dependent on LasR and the autoinducer, whether provided endogenously or exogenously. Increased <i>lasI</i> expression in ∆<i>ptsP</i> (or ∆<i>ptsO</i>) cells was partly due to the presence of unphosphorylated PtsN, which alone was sufficient to elevate <i>lasI</i> expression. However, we observed residual increases in ∆<i>ptsP</i> or ∆<i>ptsO</i> cells even in the absence of PtsN, suggesting that PtsP and PtsO can regulate gene expression independently of PtsN. Indeed, genetically disrupting the PtsO phosphorylation site impacted gene expression in the absence of PtsN, and transcriptomic evidence suggested that PtsO and PtsN have distinct regulons. Our results expand our view of how the PTS^Ntr components function both within and apart from the classic phosphorylation cascade to regulate key virulence behaviors in <i>P. aeruginosa</i>.</p><p><strong>Importance: </strong><i>Pseudomonas aeruginosa</i> often causes severe and difficult-to-treat infections. <i>P. aeruginosa</i> virulence requires the nitrogen-related phosphotransferase system (PTS^Ntr), which comprises the phosphocarrier proteins PtsP and PtsO and the final phosphoacceptor, PtsN. The PTS^Ntr is known to modulate quorum sensing, but little is known about the mechanism of regulation. Here, we examined quorum sensing regulation by the PTS^Ntr. We showed that the PTS^Ntr increases quorum sensing-mediated activation of certain genes through the additive effects of both PtsO and PtsN. We also used transcriptomics to determine the regulons of PtsO and PtsN and found that they are largely nonoverlapping. The results position PtsO and PtsN as independent effectors in the PTS^Ntr and shed new light on virulence regulation in this important pathogen.</p>","PeriodicalId":15107,"journal":{"name":"Journal of Bacteriology","volume":" ","pages":"e0004825"},"PeriodicalIF":3.0,"publicationDate":"2025-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144760137","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":"Identifying essential genes in <i>Schaalia odontolytica</i> using a saturated transposon library.","authors":"Joseph K Bedree, Jacob Bourgeois, Pooja Balani, Lujia Cen, Erik L Hendrickson, Kristopher A Kerns, Andrew Camilli, Jeffrey S McLean, Wenyuan Shi, Xuesong He","doi":"10.1128/jb.00164-25","DOIUrl":"https://doi.org/10.1128/jb.00164-25","url":null,"abstract":"<p><p>The unique epibiotic-parasitic relationship between <i>Nanosynbacter lyticus</i> type strain TM7x, a member of the newly identified candidate phyla radiation, now referred to as <i>Patescibacteria</i>, and its basibiont, <i>Schaalia odontolytica</i> strain XH001 (formerly <i>Actinomyces odontolyticus</i>), requires more powerful genetic tools for a deeper understanding of the genetic underpinnings that mediate their obligate relationship. Previous studies have mainly characterized the genomic landscape of XH001 during or post-TM7x infection through comparative genomic or transcriptomic analyses, followed by phenotypic analysis. Comprehensive genetic dissection of the pair is currently cumbersome due to the lack of robust genetic tools in TM7x. However, basic genetic tools are available for XH001, and this study expands the current genetic toolset by developing high-throughput transposon insertion sequencing (Tn-seq). Tn-seq was employed to screen for essential genes in XH001 under laboratory conditions. A highly saturated Tn-seq library was generated with nearly 660,000 unique insertion mutations, averaging one insertion every two-three nucleotides. A total of 203 genes comprising 10.5% of the XH001 genome were identified as putatively essential.IMPORTANCE<i>Schaalia odontolytica</i> strain XH001, an early colonizer of the oral multispecies biofilm (dental plaque), forms a unique epibiotic-parasitic relationship with <i>Nanosynbacter lyticus</i> type strain TM7x, a member of the newly identified <i>Patescibacteria</i> (formerly candidate phyla radiation). Achieving a mechanistic understanding of their relationship requires practical genetic tools for dissecting the roles played by different genetic mediators and shedding light on how their interspecies interaction may affect dynamics in the oral microbiome. In this study, we developed a high-throughput mutagenesis technique, Tn-seq, in XH001. The constructed Tn-seq library enabled the identification of putatively essential genes in XH001, revealing growth requirements under laboratory conditions. This library can be leveraged in future studies to elucidate TM7x's dependence on XH001 at the molecular level.</p>","PeriodicalId":15107,"journal":{"name":"Journal of Bacteriology","volume":" ","pages":"e0016425"},"PeriodicalIF":3.0,"publicationDate":"2025-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144760136","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":"Enigmatic roles of <i>Vibrio cholerae</i> hemolysin/cytolysin in the bacterial pathogenesis and host-pathogen interactions.","authors":"Mahendra Singh, Sindhoora Puravankara, Arunika Mukhopadhaya, Kausik Chattopadhyay","doi":"10.1128/jb.00248-25","DOIUrl":"https://doi.org/10.1128/jb.00248-25","url":null,"abstract":"<p><p><i>Vibrio cholerae</i> cytolysin (VCC; also known as <i>V. cholerae</i> hemolysin) is a β-barrel pore-forming toxin (β-PFT) secreted by the cholera pathogen <i>V. cholerae</i>. VCC acts to disrupt the selective permeability barrier function of the target cell membranes. Monomeric VCC molecules bind to and form heptameric transmembrane water-filled pores or channels in the lipid bilayer of the membranes, thus resulting in colloid-osmotic lysis of the target cells. Apart from its pore-forming function, VCC can activate an array of signaling cascades leading to the diverse responses that include programmed cell death, autophagy, inflammation, etc. VCC has been studied extensively focusing on the biochemical, biophysical, and structural aspects of the pore-formation mechanism. In contrast, the mechanistic basis of the VCC-mediated programmed cellular responses and their implications for bacterial pathogenesis and host-pathogen interaction processes have received less attention in the past. However, more recent studies have highlighted the crucial importance of the pore-formation-independent cellular responses for the <i>V. cholerae</i> pathogenesis process. Nevertheless, several questions regarding the pathophysiological contributions of VCC remain unanswered. In this minireview, we provide a brief account of the historical perspective of VCC in the context of <i>V. cholerae</i> pandemics, its pore-formation mechanism, and distinct cellular responses that could be evoked by this exotoxin in its target host cells. We also highlight some of the unanswered questions regarding its pathophysiological attributes and their potential contributions during the bacterial infection.</p>","PeriodicalId":15107,"journal":{"name":"Journal of Bacteriology","volume":" ","pages":"e0024825"},"PeriodicalIF":3.0,"publicationDate":"2025-07-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144731122","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":"Comparative genomics of <i>Pseudomonas paraeruginosa</i>.","authors":"Maxime Déraspe, Lori L Burrows, Romé Voulhoux, Daniela Centrón, Jacques Corbeil, Paul H Roy","doi":"10.1128/jb.00149-25","DOIUrl":"https://doi.org/10.1128/jb.00149-25","url":null,"abstract":"<p><p>The PA7-clade (or group 3) of <i>Pseudomonas aeruginosa</i> is now recognized as a distinct species, <i>Pseudomonas paraeruginosa</i>. We report here the genomic sequences of six new strains of <i>P. paraeruginosa</i>: Zw26 (the first complete genome of a cystic fibrosis isolate of <i>P. paraeruginosa</i>)<i>,</i> draft genomes of four burn and wound strains from Argentina very closely related to PA7, and of Pa5196, the strain in which arabinosylation of type IV pili was documented. We compared the genomes of 82 strains of <i>P. paraeruginosa</i> and confirmed that the species is divided into two sub-clades. Core genomes are very similar, while most differences are found in \"regions of genomic plasticity\" (RGPs). Several genomic deletions were identified, and most are common to the CR1 sub-clade that includes Zw26 and Pa5196. All strains lack the type 3 secretion system (T3SS) and instead use an alternative virulence strategy involving an exolysin, a characteristic shared with group 5 <i>P</i>. <i>aeruginosa</i>. All strains tend to be multiresistant like PA7, with a significant proportion of carbapenem-resistant strains, either <i>oprD</i> mutants or carrying carbapenemase genes. Although <i>P. paraeruginosa</i> is still relatively rare, it has a worldwide distribution. Its multiresistance and its alternative virulence strategy need to be considered in future therapeutic development.IMPORTANCE<i>Pseudomonas aeruginosa</i> is an important opportunistic pathogen causing respiratory infections, notably in cystic fibrosis, and burn and wound infections. Our study reports six new genomes of <i>Pseudomonas paraeruginosa</i>, a new species recently reported as distinct from <i>P. aeruginosa</i>. The number of sequenced genomes of <i>P. paraeruginosa</i> is only about 1% that of <i>P. aeruginosa</i>. We compare the genomic content of nearly all strains of <i>P. paraeruginosa</i> in GenBank, highlighting the differences in core and accessory genomes, antimicrobial resistance genes, and virulence factors. This novel species is very similar in environmental spectrum to <i>P. aeruginosa</i> but is notably resistant to last-line antibiotics and uses an alternative virulence strategy based on exolysin-this strategy being shared with some <i>P. aeruginosa</i> outliers.</p>","PeriodicalId":15107,"journal":{"name":"Journal of Bacteriology","volume":" ","pages":"e0014925"},"PeriodicalIF":2.7,"publicationDate":"2025-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144707535","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":"Cell surface differences within the genus <i>Methanosarcina</i> shape interactions with the extracellular environment.","authors":"Amelia-Elena Rotaru, Ghazaleh Gharib, Abdalluh Jabaley, Konstantinos Anestis, Rhitu Kotoky","doi":"10.1128/jb.00112-25","DOIUrl":"https://doi.org/10.1128/jb.00112-25","url":null,"abstract":"<p><p><i>Methanosarcina</i> are metabolically versatile methanogenic archaea that can perform extracellular electron transfer (EET), with important ecological and biotechnological implications. These archaea are broadly classified into two types (Type I and Type II) based on their energy metabolism and also differ in their aggregation-disaggregation behavior, cell surface properties, and electron transfer strategies. Type I <i>Methanosarcina</i> typically form large multicellular aggregates within a methanochondroitin extracellular matrix, thrive in organic-rich environments, play a key role in anaerobic digestion during wastewater treatment, and can perform EET. However, their mechanism of EET remains unresolved. In contrast, Type II <i>Methanosarcina</i> rely on multiheme c-type cytochromes for EET and are better adapted to low-organic, mineral-rich environments such as deep-sea sediments and aquifers, where they contribute to methane emissions. Despite their significance, the molecular mechanisms behind EET in <i>Methanosarcina</i>-particularly for Type I-remain poorly understood. This review highlights what is known and what is unknown regarding the surface biology of <i>Methanosarcina</i>, their EET strategies, and biogeochemical and industrial roles, emphasizing the need for further research to unlock their full potential in sustainable methane management.</p>","PeriodicalId":15107,"journal":{"name":"Journal of Bacteriology","volume":" ","pages":"e0011225"},"PeriodicalIF":2.7,"publicationDate":"2025-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144707534","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 urinary microbiome: the next frontier of bacterial ecology.","authors":"Seth A Reasoner, Jamisha Francis, Maria Hadjifrangiskou","doi":"10.1128/jb.00105-25","DOIUrl":"https://doi.org/10.1128/jb.00105-25","url":null,"abstract":"<p><p>The human urinary tract, once presumed to be sterile, has emerged as a new frontier of microbial ecology. Recent advancements in high-throughput sequencing technologies have revealed the complexity and diversity of microbial communities that reside within the urinary tract. This mini-review discusses the prominent bacteria identified in the urinary microbiome and their correlations with various urologic conditions. This review serves to summarize the current state of urobiome research and chart a path for ongoing discovery. Additionally, we address the methodological challenges in urinary microbiome research, emphasizing the need for standardization in study protocols and the refinement of bioinformatics tools. We highlight that although differences in urobiome composition have been described for various urologic diseases. Similarly, the pathophysiologic source and consequences of those differences remain uncertain. We outline the steps to move urobiome research from descriptive to mechanistic studies, emphasizing rigorous study design, integrating multi-omics approaches, and developing robust model systems for experimental investigation. Finally, we outline critical questions for future investigation aimed at elucidating the intricate connections between the urinary microbiome and host health.</p>","PeriodicalId":15107,"journal":{"name":"Journal of Bacteriology","volume":" ","pages":"e0010525"},"PeriodicalIF":2.7,"publicationDate":"2025-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144698612","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":"Revisiting bacterial spore germination in the presence of peptidoglycan fragments.","authors":"Rosa Heydenreich, Juliana Nacita, Chia-Wei Lin, Finn O'Dea, Stéphane Mesnage, Graham Christie, Alexander Mathys","doi":"10.1128/jb.00146-25","DOIUrl":"10.1128/jb.00146-25","url":null,"abstract":"<p><p>Bacterial spores of <i>Bacillus</i> species are metabolically inert cell types formed in response to nutrient starvation. Spores must undergo the process of germination to resume vegetative growth. This process is stimulated by the interaction of various nutrient molecules with specialized clusters of membrane-localized germinant receptors (GRs) present within spores. A second route to spore germination involving the stimulation of the PrkC Ser/Thr kinase by soluble peptidoglycan fragments was proposed in 2008 and has been subject to much less scrutiny. The current study examined the germinative response of spores of <i>Bacillus subtilis</i>, <i>Bacillus cereus,</i> and <i>Bacillus megaterium</i> when incubated in the presence of complex mixtures of peptidoglycan fragments or purified peptidoglycan fragments previously identified as germinants. The spore suspensions did not show any appreciable germination, as determined by fluorometric dipicolinic acid release, flow cytometry, or microscopy. However, the purified peptidoglycan fragments displayed a stimulatory effect on germination triggered by amino acids and nucleosides with spore GRs. In contrast, GR-mediated germination was inhibited to varying degrees by unidentified components of the complex peptidoglycan fragment mixtures derived from enzymatic digests of <i>B. subtilis</i> vegetative sacculi. Collectively, our results indicate that soluble peptidoglycan fragments cannot initiate spore germination but may influence germination via mechanisms that have yet to be established.IMPORTANCEStimuli and mechanisms that underpin bacterial spore germination are fairly well characterized. The physiological route relies upon the interaction of various small nutrient molecules with receptor proteins buried within spores. An alternative route to germination, whereby fragments of bacterial cell wall material-peptidoglycan-were proposed to stimulate a different receptor system, was proposed more recently (I. M. Shah, M. H. Laaberki, D. L. Popham and J. Dworkin, Cell 135:486-496, 2008, https://doi.org/10.1016/j.cell.2008.08.039). Results from the current study, where spores of several species of <i>Bacillus</i> were exposed to various peptidoglycan fragment-containing solutions, do not support this model of germination. This is significant since knowledge of germination can be exploited in a practical sense, as germinated spores are much easier to eradicate-in food processing and healthcare settings, for example-than their dormant counterparts.</p>","PeriodicalId":15107,"journal":{"name":"Journal of Bacteriology","volume":" ","pages":"e0014625"},"PeriodicalIF":2.7,"publicationDate":"2025-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12288470/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144553667","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}