Journal of Bacteriology最新文献

{"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":"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":"2025-08-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12369361/pdf/","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":"OA","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":"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":"2025-08-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12369347/pdf/","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":"OA","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":"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":"2025-08-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12369381/pdf/","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":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"<i>Staphylococcus aureus</i>: a model for bacterial cell biology and pathogenesis.","authors":"Mariana G Pinho, Friedrich Götz, Andreas Peschel","doi":"10.1128/jb.00106-25","DOIUrl":"10.1128/jb.00106-25","url":null,"abstract":"<p><p><i>Staphylococcus aureus</i> has emerged as an important model organism in bacterial cell biology and pathogenesis due to its clinical relevance, genetic versatility, and adaptability. This review explores how <i>S. aureus</i> has contributed to advances in the fields of bacterial cell wall synthesis and cell division, particularly due to its minimal cell wall synthesis machinery and simple spherical shape. <i>S. aureus</i> has also been fundamental in antimicrobial resistance studies, particularly due to the increasing threat of antibiotic-resistant <i>S. aureus</i> strains. Furthermore, <i>S. aureus</i>' dual lifestyle as both a commensal and a pathogen has provided key insights into host-microbe interactions, biofilm formation, and immune evasion strategies. This review underscores the importance of continued research on <i>S. aureus</i> as a basis for the development of novel antimicrobial strategies and vaccine approaches.</p>","PeriodicalId":15107,"journal":{"name":"Journal of Bacteriology","volume":" ","pages":"e0010625"},"PeriodicalIF":3.0,"publicationDate":"2025-08-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12369386/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144698611","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":"Phosphorylation of the cell wall hydrolase MltG in response to cell wall stress modulates resistance toward cephalosporins in <i>Enterococcus faecalis</i>.","authors":"Alexis A U Knotek, Christopher J Kristich","doi":"10.1128/jb.00099-25","DOIUrl":"10.1128/jb.00099-25","url":null,"abstract":"<p><p><i>Enterococcus faecalis</i> is an opportunistic pathogen that colonizes the human gut microbiome. <i>E. faecalis</i> commonly establishes infection subsequent to antibiotic therapy in patients due to intrinsic resistance exhibited by <i>E. faecalis</i> toward cephalosporins and acquired resistance to many clinically used antibiotics. Intrinsic resistance toward cephalosporins in <i>E. faecalis</i> depends on the kinase activity of IreK, a transmembrane serine/threonine PASTA kinase that mediates responses to cell wall stress, including stress caused by cephalosporins, by phosphorylating downstream effector proteins. Our previous phosphoproteomics analysis identified MltG, a transmembrane protein with an extracellular catalytic domain that cleaves nascent peptidoglycan strands, as a putative substrate for phosphorylation by IreK in <i>E. faecalis</i>, suggesting the hypothesis that IreK-mediated phosphorylation of MltG might regulate cell wall homeostasis and possibly intrinsic cephalosporin resistance. Here we report that MltG is a bona fide direct substrate of IreK in <i>E. faecalis</i>. We found that MltG phosphorylation <i>in vivo</i> is enhanced in response to cell wall stress in an IreK-dependent manner, requiring a specific residue in the MltG cytoplasmic domain for phosphorylation by IreK both <i>in vivo</i> and <i>in vitro</i>. Finally, phosphoablative and phosphomimetic substitutions of MltG reciprocally influence resistance of <i>E. faecalis</i> to ceftriaxone, pointing to functional consequences of MltG phosphorylation. Collectively, our results reveal a novel pathway by which IreK senses antibiotic-mediated cell wall stress and responds by phosphorylating the cytoplasmic segment of MltG to enhance antibiotic resistance.IMPORTANCEInfections caused by <i>Enterococcus faecalis</i> are increasingly prevalent and difficult to treat due to the multi-drug resistance exhibited toward common antibiotics. A greater understanding of the mechanisms underlying antibiotic resistance can enable the development of new drugs or strategies to overcome antibiotic-resistant infections. <i>E. faecalis</i> exhibits intrinsic resistance toward cephalosporins. This intrinsic resistance requires activity of the PASTA kinase IreK; however, few substrates for phosphorylation by IreK have been rigorously identified. Here, we report that MltG is directly phosphorylated by IreK in response to cell wall stress. This phosphorylation event acts to promote cephalosporin resistance as part of the IreK signaling network. Our results thereby validate a new substrate and expand knowledge of the IreK signaling pathway contributing to cephalosporin resistance.</p>","PeriodicalId":15107,"journal":{"name":"Journal of Bacteriology","volume":" ","pages":"e0009925"},"PeriodicalIF":3.0,"publicationDate":"2025-08-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12369325/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144626435","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":"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":"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":"2025-08-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12369343/pdf/","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":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A single point mutation is sufficient to drive <i>syp</i>-dependent biofilm formation and promote colonization by <i>Vibrio fischeri</i>.","authors":"Brittany L Fung, Elizabeth G Musto, Linsey Kathure Mugambi, Madison L Lange, Jovanka Tepavcevic, Karen L Visick","doi":"10.1128/jb.00131-25","DOIUrl":"10.1128/jb.00131-25","url":null,"abstract":"<p><p>Symbiotic colonization by <i>Vibrio fischeri</i> relies on the <i>syp</i> gene cluster, which encodes proteins predicted to synthesize and export a polysaccharide, SYP, that functions in cell-cell adherence. In strain ES114, four two-component sensor kinase/phosphatases, including central regulator SypF and the nitric oxide/HnoX-controlled HahK, dictate the activities of two response regulators, SypG and SypE, which in turn control SYP production. Here, we report that a single nucleotide change (C/A) upstream of the <i>hnoX-hahK</i> operon caused a substantial 80-fold increase in its transcription. While a search for negative regulators yielded Zur (zinc uptake regulator), loss of Zur only modestly (approximately threefold) increased transcription. We found instead that the C/A change engendered a new transcriptional start site. Furthermore, the C/A change was sufficient to robustly promote <i>syp</i>-dependent biofilm formation dependent on HahK and SypG but only partially dependent on the central regulator SypF. Rather, the residual biofilm formation in the absence of SypF relied on the luminescence regulator LuxU. Consistent with its ability to produce <i>syp</i>-dependent biofilms, a Δ<i>sypF</i> mutant that carried the C/A-<i>hahK</i> allele outcompeted its Δ<i>sypF</i> parent for squid colonization. Finally, bioinformatic analyses of the <i>hnoX</i> promoter region in various <i>V. fischeri</i> isolates revealed that most contained G or C nucleotides lacking in ES114, indicating an evolutionary divergence between different isolates. Together, these findings uncover the ability of HahK to signal through both SypF and LuxU to induce <i>syp</i>-dependent biofilm formation and host colonization, thus advancing our understanding of the regulators that control <i>syp</i>-dependent biofilm formation by <i>V. fischeri</i>.IMPORTANCEBiofilms promote the attachment of bacteria to each other and to surfaces. For <i>Vibrio fischeri</i>, biofilm formation dependent on the symbiosis polysaccharide (<i>syp</i>) locus promotes colonization of its symbiotic host. Multiple two-component regulators, including the central sensor kinase SypF and nitric oxide/HnoX-controlled sensor kinase HahK, induce SYP production. Here, we identify a C/A change in the <i>hnoX-hahK</i> regulatory region that substantially increases its transcription and SYP-dependent biofilm formation. We further determined that HahK signals through both SypF and the luminescence regulator LuxU to promote biofilm formation and host colonization. Our findings thus provide insight into the regulatory crossover between two major pathways, quorum sensing-controlled luminescence and biofilm formation, in <i>V. fischeri</i>.</p>","PeriodicalId":15107,"journal":{"name":"Journal of Bacteriology","volume":" ","pages":"e0013125"},"PeriodicalIF":3.0,"publicationDate":"2025-08-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12369376/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144626404","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":"Thank you to our retiring editors Anke Becker and Conrad Mullineaux.","authors":"George A O'Toole","doi":"10.1128/jb.00309-25","DOIUrl":"https://doi.org/10.1128/jb.00309-25","url":null,"abstract":"","PeriodicalId":15107,"journal":{"name":"Journal of Bacteriology","volume":" ","pages":"e0030925"},"PeriodicalIF":3.0,"publicationDate":"2025-08-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144816729","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}

{"title":"Functional consequences of genetic variations in DgoR, a GntR/FadR family transcriptional repressor of D-galactonate metabolism in <i>Escherichia coli</i>.","authors":"Swati Singh, Rajesh Mishra, Richa Ashok Kakkar, Shivam Singla, Akhil Pratap, Gaurav Sharma, Monika Sharma, Rachna Chaba","doi":"10.1128/jb.00103-25","DOIUrl":"10.1128/jb.00103-25","url":null,"abstract":"<p><p>Genetic variations in transcriptional regulators (TRs) of metabolic loci can influence host-bacterial interactions by affecting carbon utilization. Although the metabolism of sugar acids, including D-galactonate, is extensively implicated in the colonization and virulence of enteric bacteria, there has been no investigation on the extent of variations in their pathway-specific TRs. DgoR, the TR of D-galactonate metabolism, is the best-characterized GntR/FadR family sugar acid TR in enteric bacteria, recognized by the presence of an N-terminal winged helix-turn-helix DNA-binding domain and a C-terminal effector-binding and oligomerization (E-O) domain connected by a linker. Here, we examined 340 <i>Escherichia coli</i> isolates for variations in <i>dgoR</i> and studied their effect on repressor function. Genetic and biochemical studies identified variants with a partial loss of DNA-binding ability (P24L and A152E) and a decreased response to D-galactonate (R71C and P92L). Because the linker residue R71C resulted in a reduced response to D-galactonate and the E-O domain residue A152E led to a DNA binding defect, we performed simulations to probe their altered allosteric behavior. We observed that the correlation patterns, dynamics, and networks of the variants are indeed distinct from the wild type. Importantly, corroborating their repressor function, R71C and A152E variations impacted the growth of natural isolates in D-galactonate. Alignment-based variation detection across all <i>E. coli</i> and Enterobacterales identical protein group data sets revealed less prevalence of these four variations. Collectively, the present study highlights the need for a thorough analysis of the effect of variations in sugar acid TRs on repressor function and their effect on host-bacterial interactions.IMPORTANCESugar acids are used as carbon sources by enteric bacteria, both commensals and pathogens, with numerous studies highlighting their importance in host-bacterial interactions. Here, taking <i>Escherichia coli</i> DgoR, the transcriptional regulator (TR) of D-galactonate metabolism, as a representative, we showed that genetic variations in sugar acid TRs can affect their function and impact the utilization of these carbon sources by natural isolates. As the ability to use limiting nutrients enables bacteria to compete with the complex microbial community of the host, our study emphasizes the need for a comprehensive analysis of variations in sugar acid TRs to determine whether they influence the competition. These studies can help envision approaches for promoting the growth of commensals to eliminate their pathogenic counterparts.</p>","PeriodicalId":15107,"journal":{"name":"Journal of Bacteriology","volume":" ","pages":"e0010325"},"PeriodicalIF":3.0,"publicationDate":"2025-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12288454/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144266309","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}