Journal of Bacteriology最新文献

{"title":"Loss of LasR function leads to decreased repression of <i>Pseudomonas aeruginosa</i> PhoB activity at physiological phosphate concentrations.","authors":"Amy Conaway, Dallas L Mould, Igor Todorovic, Deborah A Hogan","doi":"10.1128/jb.00189-24","DOIUrl":"10.1128/jb.00189-24","url":null,"abstract":"<p><p>The <i>Pseudomonas aeruginosa</i> LasR transcription factor plays a role in quorum sensing (QS) across phylogenetically distinct lineages. However, isolates with loss-of-function mutations in <i>lasR</i> (LasR- strains) are commonly found in diverse settings, including infections where they are associated with worse clinical outcomes. In LasR- strains, the LasR-regulated transcription factor RhlR can also be stimulated by the activity of the two-component system PhoR-PhoB in low-inorganic phosphate (Pi) conditions. Here, we demonstrate a novel link between LasR and PhoB in which the absence of LasR increases PhoB activity at physiological Pi concentrations and increases the Pi concentration necessary for PhoB inhibition. PhoB activity was also less sensitive to repression by Pi in mutants lacking different QS regulators (RhlR and PqsR) and in mutants lacking genes required for QS-induced phenazine production, suggesting that decreased phenazine production is one reason for increased PhoB activity in LasR- strains. In addition, the CbrA-CbrB two-component system, which can be more active in LasR- strains, was necessary for increased PhoB activity in LasR- strains, and loss of the CbrA-CbrB-controlled translational repressor Crc was sufficient to activate PhoB in LasR+ <i>P. aeruginosa</i>. Phenazines and CbrA-CbrB affected PhoB activity independently. The ∆<i>lasR</i> mutant also had PhoB-dependent growth advantages in the Pi-deplete medium and increased virulence-associated gene expression at physiological Pi, in part through reactivation of QS. This work suggests PhoR-PhoB activity may contribute to the fitness and virulence of LasR- <i>P. aeruginosa</i> and subsequent clinical outcomes.IMPORTANCELoss-of-function mutations in the gene encoding the <i>Pseudomonas aeruginosa</i> quorum sensing (QS) regulator LasR occur frequently and are associated with worse clinical outcomes. We have found that LasR- <i>P. aeruginosa</i> have elevated PhoB activity at physiological concentrations of inorganic phosphate (Pi). PhoB activity promotes Pi acquisition as well as the expression of QS and virulence-associated genes. Previous work has shown that PhoB induces RhlR, another QS regulator, in a LasR- mutant in low-Pi conditions. Here, we demonstrate a novel relationship wherein LasR represses PhoB activity through the production of phenazines and Crc-mediated translational repression. This work suggests PhoB activity may contribute to the increased virulence of LasR- <i>P. aeruginosa</i>.</p>","PeriodicalId":15107,"journal":{"name":"Journal of Bacteriology","volume":" ","pages":"e0018924"},"PeriodicalIF":2.7,"publicationDate":"2025-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12186492/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143991148","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":"A deoxynucleoside triphosphate triphosphohydrolase promotes cell cycle progression in <i>Caulobacter crescentus</i>.","authors":"Chandler N Hellenbrand, David M Stevenson, Katarzyna A Gromek, Daniel Amador-Noguez, David M Hershey","doi":"10.1128/jb.00145-25","DOIUrl":"10.1128/jb.00145-25","url":null,"abstract":"<p><p>Intracellular pools of deoxynucleoside triphosphates (dNTPs) are strictly maintained throughout the cell cycle to ensure accurate and efficient DNA replication. DNA synthesis requires an abundance of dNTPs, but elevated dNTP concentrations in nonreplicating cells delay entry into S phase. Enzymes known as deoxyguanosine triphosphate triphosphohydrolases (Dgts) hydrolyze dNTPs into deoxynucleosides and triphosphates, and we propose that Dgts restrict dNTP concentrations to promote the G1 to S phase transition. We characterized a Dgt from the bacterium <i>Caulobacter crescentus</i> termed <i>flagellar signaling suppressor C</i> (<i>fssC</i>) to clarify the role of Dgts in cell cycle regulation. Deleting <i>fssC</i> increases dNTP levels and extends the G1 phase of the cell cycle through a mechanism independent of the response regulator CtrA. Segregation and duplication of the chromosomal origin of replication (<i>oriC</i>) are delayed in ∆<i>fssC</i>, but the rate of replication elongation is unchanged. We conclude that dNTP hydrolysis by FssC promotes the initiation of DNA replication. This work further establishes Dgts as important regulators of the G1 to S phase transition, and the high conservation of Dgts across all domains of life implies that Dgt-dependent cell cycle control may be widespread in many organisms.IMPORTANCECells must faithfully replicate their genetic material in order to proliferate. Studying the regulatory pathways that determine when a cell initiates DNA replication is important for understanding fundamental biological processes, and it can also improve the strategies used to treat diseases that affect the cell cycle. Here, we identify a nucleotide signaling pathway that influences when cells begin DNA replication. We show that this pathway promotes the transition from the G1 to the S phase of the cell cycle in the bacterium <i>Caulobacter crescentus</i> and propose that this pathway is prevalent in all domains of life.</p>","PeriodicalId":15107,"journal":{"name":"Journal of Bacteriology","volume":" ","pages":"e0014525"},"PeriodicalIF":2.7,"publicationDate":"2025-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12186491/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144199205","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":"Environmental pH controls antimicrobial production by human probiotic <i>Streptococcus salivarius</i>.","authors":"Dieu Linh Nguyen, Subhasree Saha, Aswin Thacharodi, Bharat Bhushan Singh, Sonali Mitra, Hackwon Do, Muthiah Kumaraswami","doi":"10.1128/jb.00059-25","DOIUrl":"10.1128/jb.00059-25","url":null,"abstract":"<p><p><i>Streptococcus salivarius</i> K12 (SAL) is an oral probiotic used to treat or prevent oral infections caused by human pathogens. SAL produces at least three antimicrobials to exert its antimicrobial activity, namely, salivaricin A and salivaricin B, and the newly identified salivabactin. Salivabactin production is catalyzed by a polyketide/non-ribosomal peptide synthase hybrid biosynthetic gene cluster (BGC), termed as <i>sar-BGC</i>. The <i>sar-BGC</i> expression and salivabactin production are transient during SAL growth <i>in vitro</i> and <i>in vivo</i>, which may negatively impact SAL probiotic efficacy. To understand the molecular basis for transient <i>sar-BGC</i> expression, we assessed the impact of environmental pH on <i>sar-BGC</i> expression. We found that environmental acidification is a critical factor in promoting salivabactin antimicrobial activity and production by inducing <i>sar-BGC</i> expression. We further showed that acidic pH directly influences the quorum-sensing system that controls <i>sar-BGC</i> expression. During environmental acidification, SAL cytosol is acidified, which is sensed by a pH-sensitive histidine switch in the cytosolic transcription regulator, NrpR. The protonation of histidine during cytosolic acidification promotes high-affinity interactions between NrpR and its cognate intercellular signaling peptide, NIP, which leads to upregulation of <i>sar-BGC</i> expression. Collectively, our results indicate that SAL uses a sophisticated regulatory mechanism to orchestrate salivabactin production in an environment that is conducive to its antimicrobial activity.</p><p><strong>Importance: </strong>Probiotic bacteria are important tools in combating bacterial infections. Probiotics exert their antimicrobial activity via several mechanisms, including antimicrobial production. However, discrepancies exist between the <i>in vitro</i> and <i>in vivo</i> efficacies of probiotics in inhibiting pathogen growth. Understanding the host and environmental factors that influence antimicrobial production and activity is critical for improving probiotic efficacy. In this study, we showed that the antimicrobial salivabactin produced by human oral probiotic <i>Streptococcus salivarius</i> K12 is active at acidic pH. We further elucidated the molecular mechanism by which <i>S. salivarius</i> coordinates salivabactin production in concert with environmental acidification, thereby maximizing salivabactin antimicrobial activity.</p>","PeriodicalId":15107,"journal":{"name":"Journal of Bacteriology","volume":" ","pages":"e0005925"},"PeriodicalIF":2.7,"publicationDate":"2025-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12186490/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144199206","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":"From lab reagent to metabolite: the riboswitch ligand guanidine as a relevant compound in bacterial physiology.","authors":"Payton Bowman, Hubert Salvail","doi":"10.1128/jb.00073-25","DOIUrl":"10.1128/jb.00073-25","url":null,"abstract":"<p><p>Efforts of the last 20 years in validating novel riboswitches led to the identification of numerous new motifs recognizing compounds with well-established biological functions. However, the recent characterization of widespread classes of riboswitches binding the nitrogen-rich compound guanidine raised questions regarding its physiological significance that has so far remained elusive. Recent findings established that certain bacterial species assimilate guanidine as a nitrogen source via guanidine-specific enzymes and transporters and that complete ammonium oxidizers can use it as a sole source of energy, reductant, and nitrogen. The frequent association of guanidine riboswitches with genes encoding guanidine efflux transporters also hints that bacteria may experience the burden of guanidine as a stressor during their lifestyle. A major gap in understanding the biology of guanidine resides in its natural source. While metabolic pathways responsible for guanidine synthesis were defined in plants, only a few guanidine-producing enzymes have been identified in bacteria, despite indications that the model organism <i>E. coli</i> may produce guanidine. This review summarizes how riboswitch research unveiled guanidine as an important compound in living organisms and the recent findings advancing our knowledge of guanidine biology. We also highlight open questions that will orient future research aiming at gaining further insights into the biological relevance of guanidine.</p>","PeriodicalId":15107,"journal":{"name":"Journal of Bacteriology","volume":" ","pages":"e0007325"},"PeriodicalIF":2.7,"publicationDate":"2025-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12186494/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144119731","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":"Bacterial ribosome heterogeneity facilitates rapid response to stress.","authors":"Yi-Lin Shen, Lei Xu, Ying Zhou, Bang-Ce Ye","doi":"10.1128/jb.00058-25","DOIUrl":"10.1128/jb.00058-25","url":null,"abstract":"<p><p>Bacteria live under constant pressure from external signals, necessitating a rapid capacity to reprogram their metabolism. The ribosome, once considered a uniform and static entity, is now recognized for its compositional heterogeneity. Despite its prevalence, the role of this heterogeneity in regulating bacterial translation remains incompletely understood. This review explores how ribosomal heterogeneity may serve as a conserved mechanism for fine-tuning gene expression, enabling swift adjustments to environmental stress. We present recent findings on the regulatory potential of ribosome heterogeneity and its broader implications for bacterial adaptation, pathogenesis, and the development of novel antimicrobial strategies.</p>","PeriodicalId":15107,"journal":{"name":"Journal of Bacteriology","volume":" ","pages":"e0005825"},"PeriodicalIF":2.7,"publicationDate":"2025-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12186496/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144208564","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 CarSR two-component system directly controls <i>radD</i> expression as a global regulator that senses bacterial coaggregation in <i>Fusobacterium nucleatum</i>.","authors":"Bibek G C, Chenggang Wu","doi":"10.1128/jb.00529-24","DOIUrl":"10.1128/jb.00529-24","url":null,"abstract":"<p><p>Two-component systems (TCS) enable bacteria to sense and respond to environmental signals, facilitating rapid adaptation. <i>Fusobacterium nucleatum</i>, a key oral pathobiont, employs the CarSR TCS to modulate coaggregation with various gram-positive partners by regulating the expression of <i>radD</i>, encoding a surface adhesion protein, as revealed by RNA-Seq analysis. However, the direct regulation of the <i>radD</i>-containing operon (<i>radABCD</i>) by the response regulator CarR, the broader CarR regulon, and the signals sensed by this system remain unclear. In this study, chromatin immunoprecipitation followed by high-throughput DNA sequencing (ChIP-seq) identified approximately 161 CarR-enriched loci across the genome and a 17 bp consensus motif that likely serves as the CarR-binding site. Notably, one such binding motif was found in the promoter region of the <i>radABCD</i> operon. The interaction of CarR with this binding motif was further validated using electrophoretic mobility shift assays, mutagenesis, and DNase I footprinting analyses. Beyond regulating <i>radABCD</i>, CarR directly controls genes involved in fructose and amino acid (cysteine, glutamate, lysine) utilization, underscoring its role as a global regulator in <i>F. nucleatum</i>. Lastly, we discovered that RadD-mediated coaggregation enhances <i>radD</i> expression, and deletion of <i>carS</i> abolished this enhancement, suggesting that coaggregation itself serves as a signal sensed by this TCS. These findings provide new insights into the CarR regulon and the regulation of RadD, elucidating the ecological and pathogenic roles of <i>F. nucleatum</i> in dental plaque formation and disease processes.IMPORTANCE<i>Fusobacterium nucleatum</i> is an essential member of oral biofilms acting as a bridging organism that connects early and late colonizers, thus driving dental plaque formation. Its remarkable ability to aggregate with diverse bacterial partners is central to its ecological success, yet the mechanisms it senses and responds to these interactions remain poorly understood. This study identifies the CarSR two-component system as a direct regulator of RadD, a major adhesin mediating coaggregation, and reveals its role in sensing coaggregation as a signal. These findings uncover a novel mechanism by which <i>F. nucleatum</i> dynamically adapts to polymicrobial environments, offering new perspectives on biofilm formation and bacterial communication in complex oral microbial ecosystems.</p>","PeriodicalId":15107,"journal":{"name":"Journal of Bacteriology","volume":" ","pages":"e0052924"},"PeriodicalIF":2.7,"publicationDate":"2025-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12186487/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144110881","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>Kolteria novifilia,</i> a novel planctomycetotal strain from the volcanic habitat of Panarea divides by unusual lateral budding.","authors":"Nicolai Kallscheuer, Christian Boedeker, Sandra Wiegand, Timo Kohn, Anja Heuer, Jörg Overmann, Stijn Peters, Mareike Jogler, Manfred Rohde, Christian Jogler","doi":"10.1128/jb.00337-24","DOIUrl":"https://doi.org/10.1128/jb.00337-24","url":null,"abstract":"<p><p>Members of the phylum <i>Planctomycetota</i> are ubiquitous bacteria that play important roles in the global carbon and nitrogen cycle. In this study, we sampled the shallow-sea hydrothermal vent system close to Panarea Island, Italy, and analyzed the bacterial diversity in this habitat using a cultivation-independent amplicon sequencing approach. Motivated by the observed abundance of members of the phylum <i>Planctomycetota</i>, we employed cultivation conditions that facilitate the enrichment of planctomycetes and isolated strain Pan216^T. This strain shows a rarely observed type of cell division-lateral budding. Based on 16S rRNA gene- and multi-locus sequence analyses, its phylogenetic position in the phylum <i>Planctomycetota</i> appears vague. Strain Pan216^T clustered between the different described families in the class <i>Planctomycetia</i>. The novel isolate shares the highest sequence identity (85.4%) of the 16S rRNA gene with <i>Thermostilla marina</i> SVX8^T, indicating that this strain belongs to a novel family. In addition to its uncommon cell division mode, Pan216^T cells are pill-shaped and covered by a putative outer surface layer. Genomic analyses of strain Pan216^T revealed many giant genes, putative S-layer protein-encoding genes, and only a limited set of canonical cell division genes. Based on the results of the polyphasic analysis, we conclude that strain Pan216^T constitutes a novel family within the phylum <i>Planctomycetota</i>, for which we propose the name <i>Kolteriaceae</i> fam. nov. The novel species <i>Kolteria novifilia</i> gen. nov., sp. nov. is represented by the type strain Pan216^T (= DSM 100414^T = CECT 9536^T).</p><p><strong>Importance: </strong>We describe a novel family of the underrepresented bacterial phylum <i>Planctomycetota</i> that divides by unusual lateral budding. Our strain is the only validly described species that uses this mode of cell division. Furthermore, it represents the only planctomycete outside of the anammox bacteria that has an S-layer-like structure. Taken together, the novel family shows a novel mechanism of cell division that could only be studied in this species.</p>","PeriodicalId":15107,"journal":{"name":"Journal of Bacteriology","volume":" ","pages":"e0033724"},"PeriodicalIF":2.7,"publicationDate":"2025-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144475382","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":"A novel membrane stress response that blocks chromosomal replication by targeting the DnaA initiator via the ClpP protease.","authors":"Alabi Gbolahan, Tong Li, Rishit Saxena, Karen Wolcott, Aamna Sohail, Ishika Ahmed, Dhruba K Chattoraj, Elliott Crooke, Rahul Saxena","doi":"10.1128/jb.00151-25","DOIUrl":"https://doi.org/10.1128/jb.00151-25","url":null,"abstract":"<p><p>In <i>Escherichia coli</i>, membrane stress due to interrupted lipoprotein (Lpp) maturation impairs DNA replication and arrests cell growth. How Lpp maturation and DNA replication are connected remains unclear. We demonstrate that upon membrane stress, the Rcs stress-response pathway is activated, and the replication initiator DnaA is lost, which explains the replication block. However, Lon protease, a key regulator of the Rcs pathway, is not required for the DnaA loss. We further ruled out the involvement of (p)ppGpp, one of the major mediators of stress responses in bacteria. On the other hand, upon deletion of the ClpP protease gene, DnaA was stable, replication was not inhibited, and there was no cell-growth arrest. In wild-type cells, overexpression of DnaA was lethal even without the membrane stress apparently from hyperinitiation. In ∆<i>crp</i> cells, hyperinitiation was restrained, and overexpression of DnaA was able to overcome the growth arrest. <i>∆fis</i> cells, which were earlier found resistant to the membrane stress, showed DnaA stability and normal replication upon stress-inducing treatments. We conclude that DnaA loss suffices to explain the growth arrest upon the membrane stress. The stress-response pathway described here appears novel because of its independence from Lon and (p)ppGpp, which have been implicated in other stress responses that block DNA replication.</p><p><strong>Importance: </strong>The observation that DNA replication stress can block cell division in <i>E. coli</i> (SOS response) introduced the concept of checkpoint control in the cell cycle. Here, we describe a novel checkpoint control that functions in the opposite direction: membrane stress causing replication block. We show how the accumulation of precursor lipoprotein (pLpp) could block replication. The pLpp accumulation causes a response culminating in activating the ClpP protease that blocks replication by targeting the initiator DnaA. DnaA being vital and highly conserved, a detailed understanding of the response pathway is likely to open new avenues to treat bacterial infection.</p>","PeriodicalId":15107,"journal":{"name":"Journal of Bacteriology","volume":" ","pages":"e0015125"},"PeriodicalIF":2.7,"publicationDate":"2025-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144475383","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":"Recent advances in mycobacterial transcription: insights beyond the general pathway.","authors":"Nilanjana Hazra, Jayanta Mukhopadhyay","doi":"10.1128/jb.00154-25","DOIUrl":"https://doi.org/10.1128/jb.00154-25","url":null,"abstract":"<p><p>The conventional idea of prokaryotic transcription represents a collection of pathways assembled from disparate studies across diverse bacterial species. This cumulative approach, though reveals core-conserved mechanisms, likely excludes the transcriptional pathways unique to an organism. The understanding of mycobacterial transcription suffers from such generalizations as its extreme GC bias, complex RNA polymerase (RNAP), abundance of short transcripts predominating its transcriptome, extensive σ factor utilization, and a constant battle against host stress implicates a distinct transcriptional landscape. This review highlights specific insights into mycobacterial RNAP architecture, promoter recognition, and elongation dynamics, against the general comprehensive narration of bacterial transcription.</p>","PeriodicalId":15107,"journal":{"name":"Journal of Bacteriology","volume":" ","pages":"e0015425"},"PeriodicalIF":2.7,"publicationDate":"2025-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144475384","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":"Calcium signaling controls early stage biofilm formation and dispersal in <i>Vibrio fischeri</i>.","authors":"Jeremy J Esin, Karen L Visick, Abby R Kroken","doi":"10.1128/jb.00077-25","DOIUrl":"10.1128/jb.00077-25","url":null,"abstract":"<p><p>Bacterial dispersal from a biofilm is presently the least-studied step of the biofilm life cycle. The symbiotic bacterial species <i>Vibrio fischeri</i> is a model organism for studying biofilms relevant to a eukaryotic host; however, methodology is lacking to readily study the dispersal of this microbe from biofilms formed in the lab. Here, we adapted a time-lapse assay to visualize biofilm dispersal by <i>V. fischeri</i>. We observed biofilm formation and dispersal for multiple <i>V. fischeri</i> isolates, which displayed a variety of biofilm architecture phenotypes and dispersal dynamics. We then investigated <i>V. fischeri</i> strain ES114 using genetic tools and mutants available for this strain. ES114 exhibited calcium-dependent biofilm formation followed by a rapid (less than 10 min) coordinated dispersal event that occurred approximately 5 h from the experimental start. Biofilm dispersal was largely independent of the dispersal-promoting protease encoded by <i>lapG</i>. Although we found no role under our conditions for either biofilm formation or dispersal for several other factors including polysaccharides and autoinducers, we determined that biofilm formation was enhanced, and dispersal was delayed, with increased concentrations of calcium. Furthermore, biofilm formation depended on the calcium-responsive diguanylate cyclase (DGC) CasA, and dispersal could be modulated by overexpressing CasA. Our work has thus developed a new tool for the <i>V. fischeri</i> field and uncovered a key role for calcium signaling and c-di-GMP in early biofilm formation and dispersal in <i>V. fischeri</i>.</p><p><strong>Importance: </strong>Biofilm formation and dispersal are critical steps in both symbiotic and pathogenic colonization. Relative to biofilm formation, the process of dispersal in the model symbiont <i>Vibrio fischeri</i>, and other bacteria, is understudied. Here, we adapted an imaging assay to study early biofilm formation and the dispersal process in <i>V. fischeri</i>. We demonstrated that our assay can quantify biofilm formation and dispersal over time, can reveal phenotypic differences in diverse natural wild-type isolates, and is sensitive enough to investigate the impact of environmental factors. Our data confirm that calcium is a potent biofilm formation signal and identify the diguanylate cyclase CasA as a key regulator. This work leads the way for more in-depth research about unknown mechanisms of biofilm dispersal.</p>","PeriodicalId":15107,"journal":{"name":"Journal of Bacteriology","volume":" ","pages":"e0007725"},"PeriodicalIF":2.7,"publicationDate":"2025-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12186489/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143981983","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}