Journal of Bacteriology最新文献

{"title":"Effects of sporulation in an extremely poor medium on <i>Bacillus subtilis</i> spore resistance, germination, and physical properties.","authors":"Caroline Burkott, Ayoni Chakraborty, William J Bannon Iv, Jane Setlow Anetsky, James Wicander, George Korza, Holly L Maschenik, Yongqing Li, Peter Setlow","doi":"10.1128/jb.00383-26","DOIUrl":"https://doi.org/10.1128/jb.00383-26","url":null,"abstract":"<p><p>Spores of <i>Bacillus</i> species are metabolically dormant and resistant to many agents but can come back to life in germination triggered by a variety of small molecules; these spore properties vary depending on the conditions and media for spore formation. In the current work, we have compared the properties of <i>Bacillus subtilis</i> spores made in a rich medium and an extremely poor medium. Notably, spores made in the poor liquid medium had lowered resistance to wet heat and somewhat lowered resistance to hydrogen peroxide and formaldehyde. Spores made in the poor liquid medium also have an inner membrane (IM) that is more permeable and fluid compared to the IM in spores made in a rich medium. The poor liquid medium spores also germinated slower than the rich medium spores with several germinant receptor (GR) germinants but faster with the non-GR-dependent germinant dodecylamine. While the reasons for the latter differences are likely the more fluid and permeable IM in the poor medium spores, there were minimal, if any, differences between rich and poor medium spores in their levels of core water or CaDPA, two compounds that alone have major effects on spore resistance properties. These findings provide new information on the resistance and germination properties of spores of <i>B. subtilis</i>.IMPORTANCESpores of various <i>Bacillus</i> species can cause adverse effects such as food spoilage and some human diseases due to their resistance properties and ability to \"come back to life\" in spore germination. The reason for these effects has been commonly studied using spores prepared in relatively rich media, and there is a large body of literature on this. However, there have been minimal, if any, studies using spores prepared in an extremely poor medium, as was done in the current work. We believe that the findings in this work provide new insight into mechanisms of spore resistance and their germination.</p>","PeriodicalId":15107,"journal":{"name":"Journal of Bacteriology","volume":" ","pages":"e0038326"},"PeriodicalIF":3.8,"publicationDate":"2026-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149109505","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":"Loss of RafE impairs raffinose utilization and increases early pneumococcal burden in mice.","authors":"Kate P Whyte, Mark van der Linden, James C Paton, Claudia Trappetti, Anna E Sheppard, Erin B Brazel","doi":"10.1128/jb.00330-26","DOIUrl":"https://doi.org/10.1128/jb.00330-26","url":null,"abstract":"<p><p><i>Streptococcus pneumoniae</i> (the pneumococcus) is one of the most common bacterial causes of middle ear infections (otitis media) in children. These infections are highly prevalent but can be persistent and challenging to treat. The pneumococcus is a highly genetically diverse organism, but the precise molecular factors that drive infection of the ear are not fully understood. Bacterial metabolic capacity is known to play an important role in infection. Here, we explored the metabolic capacity of two serotype 3 isolates of <i>S. pneumoniae</i> obtained from the middle ear of children with otitis media. Serotype 3 is a clinically relevant serotype of concern due to its inadequate control despite its inclusion in pneumococcal conjugate vaccines. We identified one strain as unable to metabolize raffinose, and by coupling genomic and phenotypic methods, we showed that this metabolic defect was likely due to a premature stop codon in the gene encoding the raffinose-family oligosaccharide utilization system ABC transporter substrate-binding protein (<i>rafE</i>). Using a <i>S. pneumoniae</i> D39 serotype 2 strain as a model, we showed that construction of a <i>rafE</i> deletion or introduction of the variant gene resulted in an increase in the number of pneumococci in the ears of mice, suggesting that this may promote transit to, or survival at, this site. This work provides further evidence of variation at the raffinose utilization locus in pneumococci and an association with distinct virulence phenotypes. Together, this aids our understanding of these infections and may have implications for the design of new therapies and vaccines.IMPORTANCE<i>Streptococcus pneumoniae</i> is a bacterium that lives in the nose of healthy people but can cause a range of infections in the lungs, ears, brain, and blood. In this study, we explore how <i>S. pneumoniae</i> acquires nutrients and proliferates inside different sites of the body. We found that nutrient uptake pathways can differ between strains, and this changes how they infect different sites. The significance of our research is in understanding how these bacteria survive in different parts of the body, which is important for developing new ways of preventing or treating disease.</p>","PeriodicalId":15107,"journal":{"name":"Journal of Bacteriology","volume":" ","pages":"e0033026"},"PeriodicalIF":3.8,"publicationDate":"2026-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149110039","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":"Protein secretion by the type IV pilus machinery in <i>Francisella tularensis</i>.","authors":"Angela DeRosa, P Todd Benziger, Vinaya Sampath, Erik J Kopping, Huiyeon Kim, David G Thanassi","doi":"10.1128/jb.00253-26","DOIUrl":"10.1128/jb.00253-26","url":null,"abstract":"<p><p><i>Francisella tularensis</i> is a highly virulent, gram-negative bacterial pathogen that causes the zoonotic disease tularemia. <i>F. tularensis</i> infects a variety of host cells and replicates intracellularly while evading and interfering with host immune responses. The molecular mechanisms that facilitate the intracellular replication and virulence of <i>F. tularensis</i> are poorly understood. The <i>Francisella</i> genome contains a set of <i>pil</i> genes that code for the assembly of surface fibers termed type IV pili (T4P). T4P are major bacterial virulence determinants, but the function of the <i>pil</i> system during <i>F. tularensis</i> infection and intracellular growth is unclear. T4P are closely related to the type II secretion pathway, and the <i>pil</i> system of a related <i>Francisella</i> species, <i>F. novicida</i>, was shown to function in protein secretion as well as pilus assembly. To identify proteins secreted by <i>F. tularensis</i>, we analyzed the <i>F. tularensis</i> Live Vaccine Strain (LVS) using bio-orthogonal noncanonical amino acid tagging (BONCAT). Using BONCAT in conjunction with proteomics, we identified candidate proteins secreted by the wild-type LVS, as well as candidate proteins whose extracellular abundance decreased in the absence of the PilF ATPase or the PilE4 pilus subunit. Using epitope tagging of selected candidates, we validated T4P-mediated secretion of the ChiA and ChiD chitinases and the KatG catalase by the LVS. These results further our understanding of the <i>pil</i> system and protein secretion pathways in <i>F. tularensis</i>.IMPORTANCE<i>Francisella tularensis</i> is a highly virulent gram-negative bacterial pathogen and the causative agent of tularemia. <i>F. tularensis</i> lacks secretion systems utilized by other intracellular bacterial pathogens but contains <i>pil</i> genes that encode for type IV pili (T4P) and may also function in protein secretion. T4P are observed on the surface of all <i>Francisella</i> spp., but <i>pil</i>-mediated protein secretion has only been reported for <i>F. novicida</i>, which is not normally pathogenic in humans. In this study, we used bio-orthogonal noncanonical amino acid tagging to identify proteins secreted by <i>F. tularensis</i>, for which there is limited information. We demonstrate that the <i>F. tularensis pil</i> system is capable of protein secretion and validate T4P-mediated secretion of the ChiA and ChiD chitinases and the KatG catalase. These results will facilitate investigation of <i>Francisella</i> virulence mechanisms and may provide targets for therapeutic intervention.</p>","PeriodicalId":15107,"journal":{"name":"Journal of Bacteriology","volume":" ","pages":"e0025326"},"PeriodicalIF":3.8,"publicationDate":"2026-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149110026","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 lysine acetyltransferase Rv0998 coordinates transcriptional and metabolic adaptation of <i>Mycobacterium tuberculosis</i> to acidic pH.","authors":"Yi Liu, Nadia Fernandes, Valwynne Faulkner, Richard Williams, Eachan Johnson, Sandhya Visweswariah, Brian D Robertson, Gerald Larrouy-Maumus","doi":"10.1128/jb.00408-26","DOIUrl":"https://doi.org/10.1128/jb.00408-26","url":null,"abstract":"<p><p><i>Mycobacterium tuberculosis</i> (Mtb) survives host defenses by adapting to host conditions, including acid stress, during infection. A critical survival strategy involves pH homeostasis, mediated by complex signaling systems that regulate metabolic reprogramming and stress responses. While the lysine acetyltransferase Rv0998 is known to support Mtb hypoxia adaptation and metabolic flexibility, its role in acid stress remains unexplored. Here, we investigated the consequences of <i>rv0998</i> deletion in 7H9 with glucose as the major carbon source. RNA-seq analysis showed that loss of Rv0998 altered the transcriptional response to acidic pH, including changes in the DosR regulon and <i>pfkB</i>/Rv2029c. Stable isotope tracing with [U-¹³C₆]-glucose also showed reduced fractional ¹³C labeling across central carbon metabolites in the <i>rv0998</i> mutant, with the largest decrease at acidic pH observed in upper glycolytic and connected hexose-phosphate intermediates. Growth and glucose-labeling phenotypes of <i>dosR</i> and <i>pfkB</i> mutants provided focused examples of stress-responsive and carbon-metabolic processes associated with the broader Rv0998 response. These findings indicate that Rv0998 contributes to coordinated transcriptional and metabolic adaptation of Mtb to acidic pH, and support further investigation of how stress-responsive regulatory programs are coupled to carbon metabolism during acid adaptation.IMPORTANCE<i>Mycobacterium tuberculosis</i> (Mtb) persists in host environments that are both acidic and nutritionally variable, but the regulatory processes that connect these stresses to metabolism remain incompletely understood. We show that loss of the lysine acetyltransferase Rv0998 impairs growth at acidic pH when glucose is the major carbon source, and is accompanied by broad changes in gene expression and incorporation of glucose-derived carbon into central metabolites. The phenotype is not apparent when glycerol is also present, indicating that the response depends on carbon-source context. These findings identify Rv0998 as a contributor to the coordination of acid-stress adaptation and central carbon metabolism in Mtb, the bacterium that causes tuberculosis.</p>","PeriodicalId":15107,"journal":{"name":"Journal of Bacteriology","volume":" ","pages":"e0040826"},"PeriodicalIF":3.8,"publicationDate":"2026-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149110033","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 role of toxin-antitoxin systems in <i>Helicobacter pylori</i> adaptability.","authors":"Juan D Romero-Carpio, Luis D Chacón-Loría, Silvia Molina-Castro, Bradd Mendoza-Guido","doi":"10.1128/jb.00166-26","DOIUrl":"10.1128/jb.00166-26","url":null,"abstract":"<p><p>Toxin-antitoxin (TA) systems are genetic modules widely distributed across bacterial chromosomes and mobile genetic elements. Initially described as plasmid addiction systems that ensure vertical inheritance through post-segregational killing, they are now recognized as versatile regulators of bacterial adaptability. In <i>Helicobacter pylori</i>, a gastric pathogen infecting nearly half of the global population, multiple TA systems have been experimentally validated, including type I RNA-RNA modules and type II protein-protein pairs. These systems contribute to growth arrest, morphological transition from spiral to coccoid forms, biofilm formation, intracellular survival, and responses to environmental stressors, such as oxidative stress, metal availability, and antibiotic exposure. Type I AapA/IsoA modules have been linked to membrane targeting and dormancy induction, whereas certain Vap-like type II toxins act as ribonucleases and likely contribute to colonization and persistence during infection. Although hundreds of putative TA loci have been identified through bioinformatic analyses, only a small fraction has been functionally characterized, highlighting substantial knowledge gaps. This minireview summarizes experimentally validated TA systems in <i>H. pylori</i>, discusses predicted candidates, and examines their potential roles in pathogen adaptability, emphasizing their relevance to <i>H. pylori</i> persistence and pathogenicity.</p>","PeriodicalId":15107,"journal":{"name":"Journal of Bacteriology","volume":" ","pages":"e0016626"},"PeriodicalIF":3.8,"publicationDate":"2026-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13584709/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148712601","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":"High levels of antisense transcription from numerous genes in the obligate intracellular bacterium <i>Orientia tsutsugamushi</i>.","authors":"Chitrasak Kullapanich, Regan Hayward, Lars Barquist, Jeanne Salje","doi":"10.1128/jb.00564-25","DOIUrl":"10.1128/jb.00564-25","url":null,"abstract":"<p><p><i>Orientia tsutsugamushi</i> (Ot) is a cytoplasmic, gram-negative, obligate intracellular bacterium that causes the human disease scrub typhus. It has a highly repetitive genome, whereby approximately 50% is composed of multiple copies of a proliferated integrative and conjugative element, the Rickettsial amplified Genetic Element (RAGE). Previous RNA sequencing analysis revealed a high level of antisense transcription in Ot, particularly from RAGE-encoded genes, with 18% of all genes having a sense:antisense ratio <1 and 5% with a ratio <0.1. In our current study, we have confirmed the earlier RNA sequencing findings via polymerase chain reaction (PCR)-based methods and established that this antisense transcription is a consistent feature across eight distinct Ot strains. Furthermore, we have utilized PCR to monitor differences in sense and antisense expression between intracellular and extracellular bacteria. Our findings lend weight to the hypothesis that antisense transcription in Ot is a regulated mechanism, possibly playing a crucial role in the pathogen's lifecycle during infection.IMPORTANCE<i>Orientia tsutsugamushi</i> (Ot) is an obligate intracellular bacterium with a highly repetitive genome and an unusual abundance of antisense RNA transcripts. Antisense transcription has been proposed to regulate gene expression, yet its biological significance in intracellular bacteria remains unclear. By confirming high and conserved levels of antisense transcription in specific genes across multiple <i>O. tsutsugamushi</i> strains and showing that antisense expression decreases in extracellular forms, this study provides new evidence that antisense transcription is a regulated process rather than transcriptional noise. These findings suggest that antisense RNAs may play a role in controlling gene activity during the bacterial life cycle, offering insights into gene regulation in organisms with reduced and repetitive genomes.</p>","PeriodicalId":15107,"journal":{"name":"Journal of Bacteriology","volume":" ","pages":"e0056425"},"PeriodicalIF":3.8,"publicationDate":"2026-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13584714/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148712603","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":"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":"2026-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13584725/pdf/","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":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Discovery of PilU as a second type IV pilus retraction motor in <i>Myxococcus xanthus</i>.","authors":"Mahdia Rahman, Kalpana Subedi, Andrea Harms, Daniel Wall, Anke Treuner-Lange","doi":"10.1128/jb.00248-26","DOIUrl":"10.1128/jb.00248-26","url":null,"abstract":"<p><p>Type IV pili (T4P) drive social (S) motility in <i>Myxococcus xanthus</i> through cycles of extension and retraction powered by the ATPases PilB and PilT. Although the canonical retraction ATPase PilT is essential for force generation, <i>M. xanthus</i> encodes four PilT-like paralogs whose contributions to motility remain unclear. Here, we identify MXAN_1995 as the long-sought PilU protein that serves as a second T4P retraction motor. A frameshift mutation or deletion of <i>pilU</i> abolishes S-motility while preserving pilus assembly and exopolysaccharide (EPS) production, phenocopying the <i>pilT</i> mutant. Single-cell analyses revealed that Δ<i>pilU</i> mutants exhibit rare, low-force movements, consistent with a role for PilU in force generation. Fluorescence microscopy showed that PilU localizes predominantly to cell poles, similar to PilT, and that PilU localization is independent of PilT but partly dependent on core T4P assembly proteins. Notably, calcium differentially modulates motility, enhancing movement in wild-type cells while suppressing motility in Δ<i>pilU</i> mutants, indicating a role for PilU under varying environmental conditions. Structural modeling, together with an intragenic suppressor, suggests a regulatory function for the intrinsically disordered C-terminal region of PilU. As found in other bacterial species, our findings establish PilU as a secondary retraction ATPase and uncover a dual-motor retraction system that is environmentally responsive and mechanically tunable in <i>M. xanthus</i>.IMPORTANCET4P are widespread motility and adhesion systems that enable bacteria to move, interact, and form multicellular communities. While the primary retraction ATPase PilT is well characterized, the function of additional PilT-like proteins remains unclear in many species. This work provides the first mechanistic characterization of PilU in <i>Myxococcus xanthus</i>, a model for multicellular behavior and T4P biology. We show that PilU is essential for productive T4P retraction, functioning as an accessory motor that enhances or stabilizes PilT-driven force generation. We further reveal that PilU activity is modulated by environmental calcium and depends on a flexible C-terminal region that influences motor dynamics. These findings uncover a dual-motor architecture that enables adaptive control of T4P retraction in response to environmental cues.</p>","PeriodicalId":15107,"journal":{"name":"Journal of Bacteriology","volume":" ","pages":"e0024826"},"PeriodicalIF":3.8,"publicationDate":"2026-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13584747/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148712637","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":"Biofilm dispersion by <i>Pseudomonas aeruginosa</i> requires relocation of BdlA to drive a switch in motility by dispersed cells.","authors":"Soyoung Park, Karin Sauer","doi":"10.1128/jb.00022-26","DOIUrl":"10.1128/jb.00022-26","url":null,"abstract":"<p><p>Biofilm dispersion is a regulated process that enables bacteria to escape as free-living cells. This response coincides with matrix degradation, reduced cyclic di-GMP levels, heightened antibiotic susceptibility, and restored flagellar motility. While dispersed cells have been reported to be motile, the mechanisms enabling motility upon induction of dispersion remain unclear. Here, we explored the regulatory mechanism of how <i>Pseudomonas aeruginosa</i> biofilm cells switch their motility phenotype to disperse from biofilms. Our findings reveal that changes in motility gene expression are initiated at the periphery of biofilms during induced dispersion, in which increased expression of the flagellar gene <i>fliC</i> is controlled by the phosphodiesterase (PDE) DipA and the chemosensory protein BdlA. In response to the dispersion signal, BdlA forms dynamic clusters and relocates to the flagellated cell pole, where it interacts with and stimulates the PDE activity of DipA, ultimately leading to elevated <i>fliC</i> expression. These findings establish a mechanistic link between signal sensing and motility reversion, demonstrating that the spatiotemporal coordination of BdlA and DipA governs the motility switch during <i>P. aeruginosa</i> biofilm dispersion.IMPORTANCEOur findings reveal a new regulatory mechanism in which dispersion signals drive BdlA relocation, activate DipA's phosphodiesterase activity, lower cyclic di-GMP, and elevate <i>fliC</i> expression. Moreover, by showing that BdlA foci formation and co-localization with DipA occur in response to dispersion signals, we demonstrate that the spatiotemporal regulation of BdlA and DipA extends the Touch-Seed-and-Go model beyond surface attachment to encompass dispersion and, thus, the reversion from a sessile to a motile growth state.</p>","PeriodicalId":15107,"journal":{"name":"Journal of Bacteriology","volume":" ","pages":"e0002226"},"PeriodicalIF":3.8,"publicationDate":"2026-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13584717/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148712658","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":"<i>Prevotella</i> in the airway: implications for lung health and pathogen defense mediated by <i>Prevotella</i>-host interactions.","authors":"Sara N Stoner, Ana Fairbanks-Mahnke, Sarah E Clark","doi":"10.1128/jb.00228-26","DOIUrl":"10.1128/jb.00228-26","url":null,"abstract":"<p><p><i>Prevotella</i> species are an extremely common and abundant bacteria detected within the low microbial biomass of the lungs and are a core component of the oral microbiome. Clinical studies have drawn associations between <i>Prevotella</i> abundance and lung homeostasis, indicating potential relationships between <i>Prevotella</i> and lung inflammation, infection defense, and lung function. Across several studies in critically ill patients, the depletion of <i>Prevotella</i> and other obligate anaerobes is linked to significantly reduced survival, leading to calls for anaerobe preservation in empiric antibiotic therapy regimens. In recent years, mechanistic studies have provided new information regarding <i>Prevotella</i>-host relationships, highlighting several processes by which <i>Prevotella</i> exposure activates epithelial, innate, and adaptive immune responses. <i>Prevotella</i> species also have direct and indirect effects on important lung bacterial pathogens, including <i>Streptococcus pneumoniae</i>, <i>Staphylococcus aureus</i>, and <i>Pseudomonas aeruginosa</i>, with <i>Prevotella</i> species-dependent consequences for pathogen infection and regulation of pathogen-induced inflammation. This review summarizes our current understanding regarding how <i>Prevotella</i> regulate lung immune homeostasis, with a discussion of key knowledge gaps necessary for the translation of these insights into new therapeutic approaches to reduce the burden of lung infection and disease.</p>","PeriodicalId":15107,"journal":{"name":"Journal of Bacteriology","volume":" ","pages":"e0022826"},"PeriodicalIF":3.8,"publicationDate":"2026-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13584745/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148712648","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}