Journal of Bacteriology最新文献

{"title":"LD-transpeptidase-mediated cell envelope remodeling enables developmental transitions and survival in <i>Coxiella burnetii</i> and <i>Legionella pneumophila</i>.","authors":"Dipak Kathayat, Yujia Huang, Joee Denis, Benjamin Rudoy, Hana Schwarz, Jacob Szlechter","doi":"10.1128/jb.00247-24","DOIUrl":"10.1128/jb.00247-24","url":null,"abstract":"&lt;p&gt;&lt;p&gt;&lt;i&gt;Coxiella burnetii&lt;/i&gt; and &lt;i&gt;Legionella pneumophila&lt;/i&gt; are two phylogenetically related bacterial pathogens that exhibit extreme intrinsic resistance when they enter into a dormancy-like state. This enables both pathogens to survive extended periods in growth-limited environments. Survival is dependent upon their ability to undergo developmental transitions into two phenotypically distinct variants, one specialized for intracellular replication and another for prolonged survival in the environment and host. We currently lack an understanding of the mechanisms that mediate these developmental transitions. Here, we performed peptidoglycan (PG) glycoproteome analysis and showed significant enrichment of PG structures catalyzed by LD-transpeptidases (LDTs) in the survival variants of &lt;i&gt;C. burnetii&lt;/i&gt; and &lt;i&gt;L. pneumophila&lt;/i&gt;. This is supported by the upregulation of LDTs, resulting in susceptibility to carbapenem antibiotics. Furthermore, deletion of the most upregulated LDT, &lt;i&gt;lpg&lt;/i&gt;1386, in &lt;i&gt;L. pneumophila&lt;/i&gt; significantly changes PG architecture, survival, and susceptibility to antibiotics. Significantly regulated by RpoS, a stationary-phase sigma factor, LDT-dependent PG remodeling is differentially activated by the host intracellular growth environment compared to axenic culture. In addition, β-barrel tethering, a newly discovered mechanism of LDT-mediated cell envelope stabilization, seems not to be specific to the survival variants. Interestingly, an outer membrane (OM) long-chain fatty acid transporter (Lpg1810) is tethered to PG in &lt;i&gt;L. pneumophila&lt;/i&gt;. Collectively, these findings show that LDT-mediated PG remodeling is a major determinant of developmental transitions and survival in &lt;i&gt;C. burnetii&lt;/i&gt; and &lt;i&gt;L. pneumophila&lt;/i&gt;. Understanding this mechanism might inform new therapeutic approaches for treating chronic infections caused by these pathogens, as well as suggest new methods to decontaminate environmental reservoirs during outbreaks.IMPORTANCE&lt;i&gt;Coxiella burnetii&lt;/i&gt; and &lt;i&gt;L. pneumophila&lt;/i&gt; cause Q Fever and Legionnaire's disease in humans, respectively. There is a lack of effective treatments for fatal chronic infections caused by these pathogens, particularly chronic Q Fever. These bacteria survive long term in nutrient-limited environments by differentiating into phenotypically distinct survival variants. Our study revealed that LDTs, a group of PG remodeling enzymes, play a prominent role in the phenotypic differentiations of these bacteria. We show that LDT-targeting carbapenems are effective against the survival variants, thus demanding the exploration of carbapenems for treating chronic infections caused by these pathogens. We report the tethering of a unique OM fatty acid transporter to PG in &lt;i&gt;L. pneumophila&lt;/i&gt; that could indicate a novel function of tethering, that is, the uptake of nutrient substrates. Homologs of this transporter are widely present in the Methylobacteriaceae family of bacteria kn","PeriodicalId":15107,"journal":{"name":"Journal of Bacteriology","volume":" ","pages":"e0024724"},"PeriodicalIF":2.7,"publicationDate":"2025-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11841132/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143023388","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":"Functions of nitroreductases in mycobacterial physiology and drug susceptibility.","authors":"Ifeanyichukwu E Eke, Robert B Abramovitch","doi":"10.1128/jb.00326-24","DOIUrl":"10.1128/jb.00326-24","url":null,"abstract":"<p><p>Tuberculosis is a respiratory infection that is caused by members of the <i>Mycobacterium tuberculosis</i> complex, with <i>M. tuberculosis</i> (Mtb) being the predominant cause of the disease in humans. The approval of pretomanid and delamanid, two nitroimidazole-based compounds, for the treatment of tuberculosis encourages the development of more nitro-containing drugs that target Mtb. Similar to the nitroimidazoles, many antimycobacterial nitro-containing scaffolds are prodrugs that require reductive activation into metabolites that inhibit the growth of the pathogen. This reductive activation is mediated by mycobacterial nitroreductases, leading to the hypothesis that these nitroreductases contribute to the specificity of the nitro prodrugs for mycobacteria. In addition to their prodrug-activating activities, these nitroreductases have different native activities that support the growth of the bacteria. This review summarizes the activities of different mycobacterial nitroreductases with respect to their activation of different nitro prodrugs and highlights their physiological functions in the bacteria.</p>","PeriodicalId":15107,"journal":{"name":"Journal of Bacteriology","volume":" ","pages":"e0032624"},"PeriodicalIF":2.7,"publicationDate":"2025-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11841060/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142949345","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>Francisella tularensis</i> universal stress protein contributes to persistence during growth arrest and paraquat-induced superoxide stress.","authors":"Benjamin Girardo, Yinshi Yue, Oksana Lockridge, Amanda M Bartling, Lawrence M Schopfer, Leonardo Augusto, Marilynn A Larson","doi":"10.1128/jb.00377-24","DOIUrl":"10.1128/jb.00377-24","url":null,"abstract":"<p><p><i>Francisella tularensis</i> is one of the most virulent bacterial pathogens known and causes the disease tularemia, which can be fatal if untreated. This zoonotic and intracellular pathogen is exposed to diverse environmental and host stress factors that require an appropriate response to survive. However, the stress tolerance mechanisms used by <i>F. tularensis</i> to persist are not fully understood. To address this aspect, we evaluated the highly conserved <u>u</u>niversal <u>s</u>tress <u>p</u>rotein (Usp) that is encoded by a single-copy gene in <i>F. tularensis</i>, unlike the majority of other bacterial pathogens that produce several to many Usp homologs. We determined that the <i>F. tularensis</i> Usp transcript is unusually stable with a half-life of over 30 minutes, and that <i>usp</i> transcript and protein levels remained abundant when exposed to low pH, nutrient deprivation, hydrogen peroxide, and paraquat. Of these and other stress conditions evaluated, the <i>F. tularensis</i> Δ<i>usp</i> mutant only exhibited reduced survival relative to the wild type during stationary phase and exposure to paraquat, a highly toxic compound that generates superoxide anions and other free radicals. Comparison of transcript levels in untreated and paraquat-treated <i>F. tularensis</i> wild type and Δ<i>usp</i> indicated that Usp contributes to enhanced expression of antioxidant defense genes, <i>oxyR</i> and <i>katG</i>. In summary, the high abundance and stability of Usp provide prompt protection during extended periods of growth arrest and free radical exposure, promoting <i>F. tularensis</i> persistence. We propose that <i>F. tularensis</i> Usp contributes to an adaptive response that prolongs viability and increases the longevity of this zoonotic pathogen in the environment.</p><p><strong>Importance: </strong><i>Francisella tularensis</i> is classified as a Tier 1 select agent due to the low infectious dose, ease of transmission, and potential use as a bioweapon. To better understand the stress defense mechanisms that contribute to the ability of this highly virulent pathogen to persist, we evaluated the conserved <i>F. tularensis</i> <u>u</u>niversal <u>s</u>tress <u>p</u>rotein (Usp). We show that <i>F. tularensis</i> Usp is unusually stable and remains abundant, regardless of the stress conditions tested, differing from other bacterial Usp homologs. We also determined that <i>F. tularensis</i> Usp enhances the expression of several critical antioxidant defense genes and increases survival during paraquat exposure and growth arrest. Determining the factors that promote <i>F. tularensis</i> persistence in the environment is needed to prevent tularemia transmission.</p>","PeriodicalId":15107,"journal":{"name":"Journal of Bacteriology","volume":" ","pages":"e0037724"},"PeriodicalIF":2.7,"publicationDate":"2025-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11841066/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143023359","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":"Structural conservation and functional role of TfpY-like proteins in type IV pilus assembly.","authors":"Ikram Qaderi, Isabelle Chan, Hanjeong Harvey, Lori L Burrows","doi":"10.1128/jb.00343-24","DOIUrl":"10.1128/jb.00343-24","url":null,"abstract":"<p><p>Type IV pili (T4P) are important virulence factors that allow bacteria to adhere to and rapidly colonize their hosts. T4P are primarily composed of major pilins that undergo cycles of extension and retraction and minor pilins that initiate pilus assembly. Bacteriophages use T4P as receptors and exploit pilus dynamics to infect their hosts. Some bacteria encode pilin accessory proteins that post-translationally glycosylate major pilins to evade phage binding. TfpY is an accessory protein of unknown function that is widespread and structurally conserved among T4P-expressing bacteria. Here, we use <i>Pseudomonas aeruginosa</i> as a model to characterize the functional role of TfpY and its homologues in pilus assembly. TfpY expression is required for optimal pilus assembly and function; however, it does not provide phage defence, unlike previously characterized accessory proteins. TfpY can cross-complement twitching in strains expressing heterologous <i>P. aeruginosa</i> pilins, suggesting TfpY and its homologues play a common role in pilus assembly. We showed that TfpY likely interacts with the major pilin and specific minor pilins but is not incorporated into the pilus itself. We propose that TfpY, along with the minor pilins at the pilus tip, primes pilus assembly. We identified two unique gain-of-function mutations in T4P regulatory genes that non-specifically restore twitching in <i>tfpY</i> mutants by increasing levels of cAMP and expression of T4P components. This study enhances our understanding of the complex functional and regulatory relationships between pilin and accessory proteins.</p><p><strong>Importance: </strong>Type IV pili are surface filaments that enable versatile pathogens, like <i>Pseudomonas aeruginosa</i>, to adhere to and colonize surfaces. Pili are composed of diverse proteins called pilins, which serve as host receptors for phages. <i>P. aeruginosa</i> uses specific accessory proteins to glycosylate pilins to evade phage infection. Here, we show that TfpY is a conserved accessory protein that does not mediate phage defence. Instead, we propose a mechanism where TfpY facilitates efficient pilus assembly and function. A better understanding of TfpY function will provide insight into how its associated pilins have evolved to resist phage infection in the absence of post-translational modification, how some phages overcome this barrier to infection, and how this can guide the design of phage-based therapeutics.</p>","PeriodicalId":15107,"journal":{"name":"Journal of Bacteriology","volume":" ","pages":"e0034324"},"PeriodicalIF":2.7,"publicationDate":"2025-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11841053/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143005913","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":"Activation and modulation of the host response to DNA damage by an integrative and conjugative element.","authors":"Saria McKeithen-Mead, Mary E Anderson, Alam García-Heredia, Alan D Grossman","doi":"10.1128/jb.00462-24","DOIUrl":"10.1128/jb.00462-24","url":null,"abstract":"<p><p>Mobile genetic elements help drive horizontal gene transfer and bacterial evolution. Conjugative elements and temperate bacteriophages can be stably maintained in host cells. They can alter host physiology and regulatory responses and typically carry genes that are beneficial to their hosts. We found that ICE<i>Bs1</i>, an integrative and conjugative element (ICE) of <i>Bacillus subtilis</i>, inhibits the host response to DNA damage (the SOS response). Activation of ICE<i>Bs1</i> before DNA damage reduced host cell lysis that was caused by SOS-mediated activation of two resident prophages. Further, activation of ICE<i>Bs1</i> itself activated the SOS response in a subpopulation of cells, and this activation was attenuated by the functions of the ICE<i>Bs1</i> genes <i>ydcT</i> and <i>yddA</i> (now <i>ramT</i> and <i>ramA</i>; <i>ram</i> for RecA modulator). Double-mutant analyses indicated that RamA functions to inhibit and RamT functions to both inhibit and activate the SOS response. Both RamT and RamA caused a reduction in RecA filaments, one of the early steps in activation of the SOS response. We suspect that there are several different mechanisms by which mobile genetic elements that generate single-stranded DNA (ssDNA) during their life cycle inhibit the host SOS response and RecA function, as RamT and RamA differ from the known SOS inhibitors encoded by conjugative elements.IMPORTANCEBacterial genomes typically contain mobile genetic elements, including bacteriophages (viruses) and integrative and conjugative elements, that affect host physiology. ICEs can excise from the chromosome and undergo rolling-circle replication, producing ssDNA, a signal that indicates DNA damage and activates the host SOS response. We found that following excision and replication, ICE<i>Bs1</i> of <i>B. subtilis</i> stimulates the host SOS response and that ICE<i>Bs1</i> encodes two proteins that limit the extent of this response. These proteins also reduce the amount of cell killing caused by resident prophages following their activation by DNA damage. These proteins are different from those previously characterized that inhibit the host SOS response and represent a new way in which ICEs can affect their host cells.</p>","PeriodicalId":15107,"journal":{"name":"Journal of Bacteriology","volume":" ","pages":"e0046224"},"PeriodicalIF":2.7,"publicationDate":"2025-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11841131/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143023426","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 rhamnose-rich O-antigen of <i>Paraburkholderia phymatum</i> MP20 is required for symbiosis with <i>Mimosa pudica</i>.","authors":"Shashini U Welmillage, Euan K James, Nisha Tak, Sonali Shedge, Lei Huang, Artur Muszyński, Parastoo Azadi, Prasad Gyaneshwar","doi":"10.1128/jb.00422-24","DOIUrl":"10.1128/jb.00422-24","url":null,"abstract":"<p><p><i>Paraburkholderia phymatum,</i> a β-proteobacterium, forms a nitrogen-fixing symbiosis with many species of the large legume genus <i>Mimosa</i> as well as with common bean (<i>Phaseolus vulgaris</i> L.). <i>Paraburkholderia</i> are considered to have evolved nodulation independently from the well-studied α-proteobacteria symbionts of legumes. However, the detailed mechanisms important for β-rhizobia-legume symbiosis have not yet been determined. In this manuscript, we have sequenced the genome of <i>P. phymatum</i> MP20, a strain isolated from <i>Mimosa pudica</i> nodules, and utilized transposon mutagenesis to identify a mutant that showed delayed and ineffective nodulation of <i>M. pudica</i>. Further analysis revealed that the mutant strain produced an altered lipopolysaccharide lacking rhamnose containing O-antigen. Complementation with the wild-type gene restored the symbiosis. Microscopic analysis of the ineffective nodules showed that the mutant strain did not infect the cortical cells but was restricted to the endodermis. The results suggest that the O-antigen of <i>P. phymatum</i> is important for the bacterial infection of cortical cells and for nodule maturation. Further research will unveil the specific involvement of the glycosyltransferase gene in LPS biosynthesis and its impact on successful nodule formation by <i>P. phymatum</i>.IMPORTANCEThe nitrogen-fixing symbiosis between legumes and rhizobia is important for agricultural and environmental sustainability. The mechanisms of the symbiotic interactions are extensively studied using α-rhizobia. In contrast, mechanisms of symbiotic interactions important for β-rhizobia and their Caesalpinioid (mimosoid) legume hosts are not well known. Here, we describe the genome sequence of <i>P. phymatum</i> MP20<i>,</i> a β-rhizobia isolated from the nodules of <i>M. pudica,</i> and isolation and characterization of a transposon mutant defective in symbiosis. We demonstrate that the O-antigen of the LPS is required for nodulation and symbiotic nitrogen fixation. This study broadens our knowledge of symbiotic interactions in β-rhizobia and will lead to a better understanding of the wider rhizobial-legume symbiosis apart from the α-rhizobia.</p>","PeriodicalId":15107,"journal":{"name":"Journal of Bacteriology","volume":" ","pages":"e0042224"},"PeriodicalIF":2.7,"publicationDate":"2025-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11841133/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143023416","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":"How FocA facilitates fermentation and respiration of formate by <i>Escherichia coli</i>.","authors":"R Gary Sawers","doi":"10.1128/jb.00502-24","DOIUrl":"10.1128/jb.00502-24","url":null,"abstract":"<p><p>Formic acid is an important source of reductant and energy for many microorganisms. Formate is also produced as a fermentation product, e.g., by enterobacteria like <i>Escherichia coli</i>. As such, formic acid shares many features in common with dihydrogen, explaining perhaps why their metabolism and physiology show considerable overlap. At physiological pH, formic acid is mainly present as the dissociated formate anion and therefore cannot diffuse freely across the cytoplasmic membrane. Specific and bidirectional translocation of formate across the cytoplasmic membrane is, however, achieved in <i>E. coli</i> by the homopentameric membrane protein, FocA. Formic acid translocation from the cytoplasm into the periplasm (efflux) serves to maintain a near-neutral cytosolic pH and to deliver formate to the periplasmically-oriented respiratory formate dehydrogenases, Fdh-N and Fdh-O. These enzymes oxidize formate, with the electrons being used to reduce nitrate, oxygen, or other acceptors. In the absence of exogenous electron acceptors, formate is re-imported into the cytoplasm by FocA, where it is sensed by the transcriptional regulator FhlA, resulting in induction of the formate regulon. The genes and operons of the formate regulon encode enzymes necessary to assemble the formate hydrogenlyase complex, which disproportionates formic acid into H₂ and CO₂. Combined, these mechanisms of dealing with formate help to maintain cellular pH homeostasis and are suggested to maintain the proton gradient during growth and in stationary phase cells. This review highlights our current understanding of how formate metabolism helps balance cellular pH, how it responds to the redox status, and how it helps conserve energy.</p>","PeriodicalId":15107,"journal":{"name":"Journal of Bacteriology","volume":" ","pages":"e0050224"},"PeriodicalIF":2.7,"publicationDate":"2025-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11841067/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143046873","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":"Impacts of <i>perR</i> on oxygen sensitivity, gene expression, and murine infection in <i>Clostridioides difficile</i> 630∆<i>erm</i>.","authors":"Anna L Gregory, Hailey E Bussan, Madeline A Topf, Andrew J Hryckowian","doi":"10.1128/jb.00468-24","DOIUrl":"10.1128/jb.00468-24","url":null,"abstract":"<p><p><i>Clostridioides difficile</i> infection (CDI), characterized by colitis and diarrhea, afflicts approximately half a million people in the USA every year, burdening both individuals and the healthcare system. <i>C. difficile</i> 630Δ<i>erm</i> is an erythromycin-sensitive variant of the clinical isolate <i>C. difficile</i> 630 and is commonly used in the <i>C. difficile</i> research community due to its genetic tractability. 630Δ<i>erm</i> possesses a point mutation in <i>perR</i>, an autoregulated transcriptional repressor that regulates oxidative stress resistance genes. This point mutation results in a constitutively de-repressed PerR operon in 630Δ<i>erm</i>. To address the impacts of <i>perR</i> on phenotypes relevant for oxygen tolerance and relevant to a murine model of CDI, we corrected the point mutant to restore PerR function in 630∆<i>erm</i> (herein, 630∆<i>erm perR</i>^WT). We demonstrate that there is no difference in growth between 630Δ<i>erm</i> and 630Δ<i>erm perR</i>^WT under anaerobic conditions or when exposed to concentrations of O₂ that mimic those found near the surface of the colonic epithelium. However, 630∆<i>erm perR</i>^WT is more sensitive to ambient oxygen than 630∆<i>erm</i>, which coincides with alterations in expression of a variety of <i>perR</i>-dependent and <i>perR</i>-independent genes. Finally, we show that 630∆<i>erm</i> and 630∆<i>erm perR</i>^WT do not differ in their ability to infect and cause disease in a well-established murine model of CDI. Together, these data support the hypothesis that the <i>perR</i> mutation in 630∆<i>erm</i> arose as a result of exposure to ambient oxygen and that the <i>perR</i> mutation in 630∆<i>erm</i> is unlikely to impact CDI-relevant phenotypes in laboratory studies.IMPORTANCE<i>Clostridioides difficile</i> is a diarrheal pathogen and a major public health concern. To improve humans' understanding of <i>C. difficile</i>, a variety of <i>C. difficile</i> isolates are used in research, including <i>C. difficile</i> 630Δ<i>erm</i>. 630Δ<i>erm</i> is a derivative of the clinical isolate 630 and is commonly studied because it is genetically manipulable. Previous work showed that a mutation in <i>perR</i> in 630Δ<i>erm</i> results in a dysregulated oxidative stress response, but no work has been done to characterize <i>perR</i>-dependent effects on the transcriptome or to determine impacts of <i>perR</i> during infection. Here, we identify transcriptomic differences between 630∆<i>erm and</i> 630∆<i>erm perR</i>^WT exposed to ambient oxygen and demonstrate that there is no strain-based difference in burdens in murine <i>C. difficile</i> infection.</p>","PeriodicalId":15107,"journal":{"name":"Journal of Bacteriology","volume":" ","pages":"e0046824"},"PeriodicalIF":2.7,"publicationDate":"2025-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11841134/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143023387","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":"Use of analytical strategies to understand spatial chemical variation in bacterial surface communities.","authors":"Abigail A Weaver, Joshua D Shrout","doi":"10.1128/jb.00402-24","DOIUrl":"10.1128/jb.00402-24","url":null,"abstract":"<p><p>Not only do surface-growing microbes such as biofilms display specific traits compared to planktonic cells, but also they display many heterogeneous behaviors over many spatial and temporal contexts. While the application of molecular genetics tools to extract or visualize gene expression or regulatory function data is now common in studying surface growth, the use of analytical chemistry tools to visualize the spatiotemporal distribution of chemical products synthesized by these surface microbes is less common. Here, we review chemical imaging tools that have been used to inform our understanding of surface-growing microbes. We highlight the use of confocal Raman Microscopy, surface-enhanced Raman spectroscopy, matrix-assisted laser desorption/ionization, secondary ion mass spectrometry, desorption electrospray ionization, and electrochemical imaging that have been applied to assess two-dimensional chemical profiles of bacteria. We specifically discuss the use of these tools to study rhamnolipids, alkylquinolones, and phenazines of the bacterium <i>Pseudomonas aeruginosa</i>.</p>","PeriodicalId":15107,"journal":{"name":"Journal of Bacteriology","volume":" ","pages":"e0040224"},"PeriodicalIF":2.7,"publicationDate":"2025-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11841061/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143052594","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 NmpRSTU multi-component signaling system of <i>Myxococcus xanthus</i> regulates expression of an oxygen utilization regulon.","authors":"Colin T McAllister, Allison M Ronk, Mason J Stenzel, John R Kirby, Daniel J Bretl","doi":"10.1128/jb.00280-24","DOIUrl":"10.1128/jb.00280-24","url":null,"abstract":"<p><p><i>Myxococcus xanthus</i> has numerous two-component signaling systems (TCSs), many of which regulate the complex social behaviors of this soil bacterium. A subset of TCSs consists of NtrC-like response regulators (RRs) and their cognate histidine sensor kinases (SKs). We have previously demonstrated that a multi-component, phosphorelay TCS named NmpRSTU plays a role in <i>M. xanthus</i> social motility. NmpRSTU was discovered through a screen that identified mutations in <i>nmp</i> genes that restored Type-IV pili-dependent motility to a nonmotile strain. The Nmp pathway begins with the SK NmpU, which is predicted to be active in the presence of oxygen. NmpU phosphorylates another SK, NmpS, a hybrid kinase containing an RR domain and a HisKA-CA domain. These two kinases work in a reciprocal fashion: when NmpU is active, NmpS is inactive, and vice versa. Finally, the phosphorelay culminates in NmpS phosphorylating the NtrC-like RR NmpR. To better understand the role of NmpRSTU in <i>M. xanthus</i> physiology, we determined the NmpR regulon by combining <i>in silico</i> predictions of the NmpR consensus binding sequence with <i>in vitro</i> electromobility shift assays (EMSAs) and <i>in vivo</i> transcriptional reporters. We identified several NmpR-dependent, upregulated genes likely to be important in oxygen utilization. Additionally, we demonstrate NmpRSTU plays a role in fruiting body development, suggesting a role for oxygen sensing in this behavior. We propose that NmpRSTU senses oxygen-limiting conditions, and NmpR upregulates genes associated with optimal utilization of that oxygen. This may be necessary for <i>M. xanthus</i> physiology and behaviors in the highly dynamic soil where oxygen concentrations vary dramatically.</p><p><strong>Importance: </strong>Bacteria use two-component signaling systems (TCSs) to respond to a multitude of environmental signals and subsequently regulate complex cellular physiology and behaviors. <i>Myxococcus xanthus</i> is a ubiquitous soil bacterium that encodes numerous two-component systems to respond to the conditions of its soil environment and coordinate multicellular behaviors such as coordinated motility, microbial predation, fruiting body development, and sporulation. To better understand how this bacterium uses a two-component system that has been linked to the sensing of oxygen concentrations, NmpRSTU, we determined the gene regulatory network of this system. We identified several genes regulated by NmpR that are likely important in oxygen utilization and for the <i>M. xanthus</i> response to varied oxygen concentrations in the dynamic soil environment.</p>","PeriodicalId":15107,"journal":{"name":"Journal of Bacteriology","volume":" ","pages":"e0028024"},"PeriodicalIF":2.7,"publicationDate":"2025-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11841059/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143046877","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}