Journal of Bacteriology最新文献

{"title":"The relationship between <i>pqs</i> gene expression and acylhomoserine lactone signaling in <i>Pseudomonas aeruginosa</i>.","authors":"Martín P Soto-Aceves, Nicole E Smalley, Amy L Schaefer, E Peter Greenberg","doi":"10.1128/jb.00138-24","DOIUrl":"10.1128/jb.00138-24","url":null,"abstract":"<p><p>The opportunistic pathogen <i>Pseudomonas aeruginosa</i> has complex quorum sensing (QS) circuitry, which involves two acylhomoserine lactone (AHL) systems, the LasI AHL synthase and LasR AHL-dependent transcriptional activator system and the RhlI AHL synthase-RhlR AHL-responsive transcriptional activator. There is also a quinoline signaling system [the <i>Pseudomonas</i> quinolone signal (PQS) system]. Although there is a core set of genes regulated by the AHL circuits, there is strain-to-strain variation in the non-core QS regulon. A size reduction of the QS regulon occurs in laboratory evolution experiments with the model strain PAO1. We used transcriptomics to test the hypothesis that reductive evolution in the PAO1 QS regulon can in large part be explained by a null mutation in <i>pqsR</i>, the gene encoding the transcriptional activator of the <i>pqs</i> operon. We found that PqsR had very little influence on the AHL QS regulon. This was a surprising finding because the last gene in the PqsR-dependent <i>pqs</i> operon, <i>pqsE</i>, codes for a protein, which physically interacts with RhlR, and this interaction is required for RhlR-dependent activation of some genes. We used comparative transcriptomics to examine the influence of a <i>pqsE</i> mutation on the QS regulon and identified only three transcripts, which were strictly dependent on PqsE. By using reporter constructs, we showed that the PqsE influence on other genes was dependent on experimental conditions and we have gained some insight about those conditions. This work adds to our understanding of the plasticity of the <i>P. aeruginosa</i> QS regulon and to the role PqsE plays in RhlR-dependent gene activation.IMPORTANCEOver many generations of growth in certain conditions, <i>Pseudomonas aeruginosa</i> undergoes a large reductive evolution in the number of genes activated by quorum sensing. Here, we rule out one plausible route of the reductive evolution: that a mutation in a transcriptional activator PqsR or the PqsR activation of <i>pqsE</i>, which codes for a chaperone for the quorum sensing signal-responsive transcription factor RhlR, explains the finding. We further provide information about the influence of PqsR and PqsE on quorum sensing in <i>P. aeruginosa</i>.</p>","PeriodicalId":15107,"journal":{"name":"Journal of Bacteriology","volume":" ","pages":"e0013824"},"PeriodicalIF":2.7,"publicationDate":"2024-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11500497/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142132849","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":"Autoproteolytic mechanism of CdiA toxin release reconstituted <i>in vitro</i>.","authors":"Ana Katrina Y Tiu, Grace C Conroy, Cedric E Bobst, Christine L Hagan","doi":"10.1128/jb.00249-24","DOIUrl":"10.1128/jb.00249-24","url":null,"abstract":"<p><p>Contact-dependent inhibition (CDI) is a mechanism of interbacterial competition in Gram-negative bacteria. Bacteria that contain CDI systems produce a large, filamentous protein, CdiA, on their cell surfaces. CdiA contains a C-terminal toxin domain that is transported across the outer membranes (OMs) of neighboring bacteria. Once inside a target bacterium, the toxin is released from the CdiA protein via a proteolytic mechanism that has not been well characterized. We have developed an <i>in vitro</i> assay to monitor this toxin release process and have identified several conserved amino acids that play critical roles in the autocatalytic mechanism. Our results indicate that a hydrophobic, membrane-like environment is required for CdiA to fold, and the proteolysis occurs through an asparagine cyclization mechanism. Our <i>in vitro</i> assay thus provides a starting point for analyzing the conformational state of the CdiA protein when it is inserted into a target cell's OM and engaged in transporting the toxin across that membrane.</p><p><strong>Importance: </strong>It is challenging to develop new antibiotics capable of killing Gram-negative bacteria because their outer membranes are impermeable to many small molecules. Some Gram-negative bacteria, however, deliver much larger protein toxins through the outer membranes of competing bacteria in their environments using contact-dependent inhibition (CDI) systems. How these toxins traverse the outer membranes of their targets is not well understood. We have therefore developed a method to study the toxin delivery process in a highly simplified system using a fragment of a CDI protein. Our results indicate that the CDI protein assembles into a structure in the target membrane that catalyzes the release of the toxin. This CDI protein fragment enables further studies of the toxin delivery mechanism.</p>","PeriodicalId":15107,"journal":{"name":"Journal of Bacteriology","volume":" ","pages":"e0024924"},"PeriodicalIF":2.7,"publicationDate":"2024-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11500576/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142347209","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 amino acid chemotaxis: a widespread strategy with multiple physiological and ecological roles.","authors":"Miguel A Matilla, Tino Krell","doi":"10.1128/jb.00300-24","DOIUrl":"10.1128/jb.00300-24","url":null,"abstract":"<p><p>Chemotaxis is the directed, flagellum-based movement of bacteria in chemoeffector gradients. Bacteria respond chemotactically to a wide range of chemoeffectors, including amino, organic, and fatty acids, sugars, polyamines, quaternary amines, purines, pyrimidines, aromatic hydrocarbons, oxygen, inorganic ions, or polysaccharides. Most frequent are chemotactic responses to amino acids (AAs), which were observed in numerous bacteria regardless of their phylogeny and lifestyle. Mostly chemoattraction responses are observed, although a number of bacteria are repelled from certain AAs. Chemoattraction is associated with the important metabolic value of AAs as growth substrates or building blocks of proteins. However, additional studies revealed that AAs are also sensed as environmental cues. Many chemoreceptors are specific for AAs, and signaling is typically initiated by direct ligand binding to their four-helix bundle or dCache ligand-binding domains. Frequently, bacteria possess multiple AA-responsive chemoreceptors that at times possess complementary AA ligand spectra. The identification of sequence motifs in the binding sites at dCache_1 domains has permitted to define an AA-specific family of dCache_1AA chemoreceptors. In addition, AAs are among the ligands recognized by broad ligand range chemoreceptors, and evidence was obtained for chemoreceptor activation by the binding of AA-loaded solute-binding proteins. The biological significance of AA chemotaxis is very ample including in biofilm formation, root and seed colonization by beneficial bacteria, plant entry of phytopathogens, colonization of the intestine, or different virulence-related features in human/animal pathogens. This review provides insights that may be helpful for the study of AA chemotaxis in other uncharacterized bacteria.</p>","PeriodicalId":15107,"journal":{"name":"Journal of Bacteriology","volume":" ","pages":"e0030024"},"PeriodicalIF":2.7,"publicationDate":"2024-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11500578/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142347210","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":"Molecular dissection of the chromosome partitioning protein RocS and regulation by phosphorylation.","authors":"Margaux Demuysere, Adrien Ducret, Christophe Grangeasse","doi":"10.1128/jb.00291-24","DOIUrl":"10.1128/jb.00291-24","url":null,"abstract":"<p><p>Chromosome segregation in bacteria is a critical process ensuring that each daughter cell receives an accurate copy of the genetic material during cell division. Active segregation factors, such as the ParABS system or SMC complexes, are usually essential for this process, but they are surprisingly dispensable in <i>Streptococcus pneumoniae</i>. Rather, chromosome segregation in <i>S. pneumoniae</i> relies on the protein Regulator of Chromosome Segregation (RocS), although the molecular mechanisms involved remain elusive. By combining genetics, <i>in vivo</i> imaging, and biochemical approaches, we dissected the molecular features of RocS involved in chromosome segregation. We investigated the respective functions of the three RocS domains, specifically the C-terminal amphipathic helix (AH), the N-terminal DNA-binding domain (DBD), and the coiled-coil domain (CCD) separating the AH and the DBD. Notably, we found that a single AH is not sufficient for membrane binding and that RocS requires prior oligomerization to interact with the membrane. We further demonstrated that this self-interaction was driven by the N-terminal part of the CCD. On the other hand, we revealed that the C-terminal part of the CCD corresponds to a domain of unknown function (DUF 536) and is defined by three conserved glutamines, which play a crucial role in RocS-mediated chromosome segregation. Finally, we showed that the DBD is phosphorylated by the unique serine-threonine kinase of <i>S. pneumoniae</i> StkP and that mimicking this phosphorylation abrogated RocS binding to DNA. Overall, this study offers new insights into chromosome segregation in Streptococci and paves the way for a deeper understanding of RocS-like proteins in other bacteria.IMPORTANCEBacteria have evolved a variety of mechanisms to properly segregate their genetic material during cell division. In this study, we performed a molecular dissection of the chromosome partitioning protein Regulator of Chromosome Segregation (RocS), a pillar element of chromosome segregation in <i>S. pneumoniae</i> that is also generally conserved in the <i>Streptococcaceae</i> family. Our systematic investigation sheds light on the molecular features required for successful pneumococcal chromosome segregation and the regulation of RocS by phosphorylation. In addition, our study also revealed that RocS shares functional domains with the Par protein, involved in an atypical plasmid segregation system. Therefore, we expect that our findings may serve to extend our understanding of RocS and RocS-like proteins while broadening the repertoire of partitioning systems used in bacteria.</p>","PeriodicalId":15107,"journal":{"name":"Journal of Bacteriology","volume":" ","pages":"e0029124"},"PeriodicalIF":2.7,"publicationDate":"2024-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11500499/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142307815","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 very versatile molecular machine.","authors":"Michael D Manson","doi":"10.1128/jb.00351-24","DOIUrl":"10.1128/jb.00351-24","url":null,"abstract":"<p><p>In this issue (J Bacteriol. 206: e0014024, https://doi.org/10.1128/jb.00140-24), Ridone and Baker describe hybrids between two 5:2 heteroheptameric ion-powered motors. Chimeras were constructed between stator units of a bacterial flagellum and ExbBD of the Ton outer-membrane transport system. Only one of the 14 hybrids supported swimming in <i>Escherichia coli</i>. Three additional residue changes at sites distant from the hybrid region enhanced motility. This work suggests that flagellar stator units and ExbBD share an ancestor that diverged during evolution to perform different tasks.</p>","PeriodicalId":15107,"journal":{"name":"Journal of Bacteriology","volume":" ","pages":"e0035124"},"PeriodicalIF":2.7,"publicationDate":"2024-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11500496/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142347208","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":"Development of inducible promoter and CRISPRi plasmids functional in <i>Rickettsia rickettsii</i>.","authors":"Adam M Nock, Tina R Clark, Ted Hackstadt","doi":"10.1128/jb.00367-24","DOIUrl":"10.1128/jb.00367-24","url":null,"abstract":"<p><p><i>Rickettsia rickettsii</i> is an obligate intracellular, tick-borne bacterium that causes Rocky Mountain spotted fever. The demanding nature of cultivating these bacteria within host cells and the labor involved in obtaining clonal isolates have severely limited progress regarding the development of compatible genetic tools to study this pathogen. Conditional expression of genes that might be toxic or have an otherwise undesirable effect is the next logical goal to expand upon the constitutive expression plasmids generated thus far. We describe the construction of an inducible promoter system based on the tet-On system, leveraging design elements from the anhydrotetracycline-inducible promoter system used for <i>Borrelia burgdorferi</i> and one of the few characterized rickettsial promoters for the outer membrane gene, <i>rompB</i> (<i>sca5</i>). The functionality of this promoter is demonstrated via fluorescence of induced mScarlet production and was then used to construct a generalized inducible expression vector for <i>R. rickettsii</i>. The development of a functional inducible promoter was then applied to the construction of a CRISPR interference plasmid as a means to reduce or essentially silence the transcription of targeted genes. We demonstrate the viability of a simplified, single vector CRISPRi system to disrupt gene expression in <i>R. rickettsii</i> targeting the type IV secreted effector <i>rarP2</i> and autotransporter peptidase <i>rapL</i> as examples.</p><p><strong>Importance: </strong>This work expands upon the genetic toolbox available for <i>R. rickettsii</i>. We describe both an inducible promoter and CRISPRi system compatible with <i>Rickettsia</i>, which may provide key instruments for the development of further tools. The development of an inducible promoter system allows for the overexpression of genes, which might be toxic when expressed constitutively. The CRISPRi system enables the ability to knock down genes with specificity, and critically, genes that may be essential and could not otherwise be knocked out. These developments may provide the foundation for unlocking genetic tools for other pathogens of the order Rickettsiales, such as the <i>Anaplasma</i>, <i>Orientia</i>, and <i>Ehrlichia</i> for which there are currently no inducible promoters or CRISPRi platforms.</p>","PeriodicalId":15107,"journal":{"name":"Journal of Bacteriology","volume":" ","pages":"e0036724"},"PeriodicalIF":2.7,"publicationDate":"2024-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11500500/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142347212","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":"Characterization of galactose catabolic pathways in <i>Streptococcus agalactiae</i> and identification of a major galactose: phosphotransferase importer.","authors":"Aurelia Hiron, Morgane Melet, Capucine Guerry, Ilona Dubois, Vanessa Rong, Philippe Gilot","doi":"10.1128/jb.00155-24","DOIUrl":"10.1128/jb.00155-24","url":null,"abstract":"<p><p>We identified and characterized genomic regions of <i>Streptococcus agalactiae</i> that are involved in the Leloir and the tagatose-6-phosphate pathways for D-galactose catabolism. The accumulation of mutations in genes coding the Leloir pathway and the absence of these genes in a significant proportion of the strains suggest that this pathway may no longer be necessary for <i>S. agalactiae</i> and is heading toward extinction. In contrast, a genomic region containing genes coding for intermediates of the tagatose-6-phosphate pathway, a Gat family PTS transporter, and a DeoR/GlpR family regulator is present in the vast majority of strains. By deleting genes that code for intermediates of each of these two pathways in three selected strains, we demonstrated that the tagatose-6-phosphate pathway is their sole route for galactose catabolism. Furthermore, we showed that the Gat family PTS transporter acts as the primary importer of galactose in <i>S. agalactiae</i>. Finally, we proved that the DeoR/GlpR family regulator is a repressor of the tagatose-6-phosphate pathway and that galactose triggers the induction of this biochemical mechanism.IMPORTANCE<i>S. agalactiae</i>, a significant pathogen for both humans and animals, encounters galactose and galactosylated components within its various ecological niches. We highlighted the capability of this bacterium to metabolize D-galactose and showed the role of the tagatose-6-phosphate pathway and of a PTS importer in this biochemical process. Since <i>S. agalactiae</i> relies on carbohydrate fermentation for energy production, its ability to uptake and metabolize D-galactose could enhance its persistence and its competitiveness within the microbiome.</p>","PeriodicalId":15107,"journal":{"name":"Journal of Bacteriology","volume":" ","pages":"e0015524"},"PeriodicalIF":2.7,"publicationDate":"2024-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11500514/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142287952","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":"Interspecies surfactants serve as public goods enabling surface motility in <i>Pseudomonas aeruginosa</i>.","authors":"Delayna L Warrell, Tiffany M Zarrella, Christopher Machalek, Anupama Khare","doi":"10.1128/jb.00281-24","DOIUrl":"10.1128/jb.00281-24","url":null,"abstract":"<p><p>In most natural environments, bacteria live in polymicrobial communities where secreted molecules from neighboring species alter bacterial behaviors, including motility, but such interactions are understudied. <i>Pseudomonas aeruginosa</i> is a motile opportunistic pathogen that exists in diverse multispecies environments, such as the soil, and is frequently found in human wound and respiratory tract co-infections with other bacteria, including <i>Staphylococcus aureus</i>. Here, we show that <i>P. aeruginosa</i> can co-opt secreted surfactants from other species for flagellar-based surface motility. We found that exogenous surfactants from <i>S. aureus</i>, other bacteria, and interkingdom species enabled <i>P. aeruginosa</i> to switch from swarming to an alternative surface spreading motility on semi-solid surfaces and allowed for the emergence of surface motility on hard agar where <i>P. aeruginosa</i> was otherwise unable to move. Although active flagellar function was required for surface spreading, known motility regulators were not essential, indicating that surface spreading may be regulated by an as yet unknown mechanism. This motility was distinct from the response of most other motile bacterial species in the presence of exogenous surfactants. Mutant analysis indicated that this <i>P. aeruginosa</i> motility was similar to a previously described mucin-based motility, \"surfing,\" albeit with divergent regulation. Thus, our study demonstrates that secreted surfactants from the host as well as neighboring bacterial and interkingdom species act as public goods facilitating <i>P. aeruginosa</i> flagella-mediated surfing-like surface motility, thereby allowing it to access different environmental niches.</p><p><strong>Importance: </strong>Bacterial motility is an important determinant of bacterial fitness and pathogenesis, allowing expansion and invasion to access nutrients and adapt to new environments. Here, we demonstrate that secreted surfactants from a variety of foreign species, including other bacterial species, infection hosts, fungi, and plants, facilitate surface spreading motility in the opportunistic pathogen <i>Pseudomonas aeruginosa</i> that is distinct from established motility phenotypes. This response to foreign surfactants also occurs in <i>Pseudomonas putida</i>, but not in more distantly related bacterial species. Our systematic characterization of surfactant-based surface spreading shows that these interspecies surfactants serve as public goods to enable <i>P. aeruginosa</i> to move and explore environmental conditions when it would be otherwise immotile.</p>","PeriodicalId":15107,"journal":{"name":"Journal of Bacteriology","volume":" ","pages":"e0028124"},"PeriodicalIF":2.7,"publicationDate":"2024-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11500613/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142132848","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":"Flagellar point mutation causes social aggregation in laboratory-adapted <i>Bacillus subtilis</i> under conditions that promote swimming.","authors":"Safiya Alvi, V Denise Mondelo, Jacqueline Boyle, Amanda Buck, Justin Gejo, Molly Mason, Shriya Matta, Abigail Sheridan, Mark A B Kreutzberger, Edward H Egelman, Anna McLoon","doi":"10.1128/jb.00199-24","DOIUrl":"10.1128/jb.00199-24","url":null,"abstract":"<p><p>Motility allows microbes to explore and maximize success in their environment; however, many laboratory bacterial strains have a reduced or altered capacity for motility. Swimming motility in <i>Bacillus subtilis</i> depends on peritrichous flagella and is carried out individually as cells move by biased random walks toward attractants. Previously, we adapted <i>Bacillus subtilis</i> strain 3610 to the laboratory for 300 generations in lysogeny broth (LB) batch culture and isolated lab-adapted strains. Strain SH2 is motility-defective and in broth culture forms large, frequently spherical aggregates of cells. A single point mutation in the flagellin gene <i>hag</i> that causes amino acid 259 to switch from A to T is necessary and sufficient to cause these social cell aggregates, and aggregation occurs between flagellated cells bearing this point mutation regardless of the strain background. Cells associate when bearing this mutation, but flagellar rotation is needed to pull associating cells into spherical aggregates. Using electron microscopy, we are able to show that the SH2 flagellar filament has limited polymorphism when compared to other flagellar structures. This limited polymorphism hinders the flagellum's ability to function as a motility apparatus but appears to alter its function to that of cell aggregation/adhesion. We speculate that the genotype-specific aggregation of cells producing Hag^A259T flagella could have increased representation in a batch-culture experiment by allowing similar cells to go through a transfer together and also that this mutation could serve as an early step to evolve sociality in the natural world.IMPORTANCEThe first life forms on this planet were prokaryotic, and the earliest environments were aquatic, and from these relatively simple starting conditions, complex communities of microbes and ultimately multicellular organisms were able to evolve. Usually, motile cells in aqueous environments swim as individuals but become social by giving up motility and secreting extracellular substances to become a biofilm. Here, we identify a single point mutation in the flagellum that is sufficient to allow cells containing this mutation to specifically form large, suspended groups of cells. The specific change in the flagellar filament protein subunits causes a unique change in the flagellar structure. This could represent a distinct way for closely related cells to associate as an early precursor to sociality.</p>","PeriodicalId":15107,"journal":{"name":"Journal of Bacteriology","volume":" ","pages":"e0019924"},"PeriodicalIF":2.7,"publicationDate":"2024-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11500573/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142154076","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":"Differential effects of inosine monophosphate dehydrogenase (IMPDH/GuaB) inhibition in <i>Acinetobacter baumannii</i> and <i>Escherichia coli</i>.","authors":"Yutian Peng, John G Moffat, Cory DuPai, Eric M Kofoed, Elizabeth Skippington, Zora Modrusan, Susan L Gloor, Kevin Clark, Yiming Xu, Shuxuan Li, Liuxi Chen, Xingrong Liu, Ping Wu, Seth F Harris, Shumei Wang, Terry D Crawford, Chun Sing Li, Zhiguo Liu, John Wai, Man-Wah Tan","doi":"10.1128/jb.00102-24","DOIUrl":"10.1128/jb.00102-24","url":null,"abstract":"<p><p>Inosine 5'-monophosphate dehydrogenase (IMPDH), known as GuaB in bacteria, catalyzes the rate-limiting step in <i>de novo</i> guanine biosynthesis and is conserved from humans to bacteria. We developed a series of potent inhibitors that selectively target GuaB over its human homolog. Here, we show that these GuaB inhibitors are bactericidal, generate phenotypic signatures that are distinct from other antibiotics, and elicit different time-kill kinetics and regulatory responses in two important Gram-negative pathogens: <i>Acinetobacter baumannii</i> and <i>Escherichia coli</i>. Specifically, the GuaB inhibitor G6 rapidly kills <i>A. baumannii</i> but only kills <i>E. coli</i> after 24 h. After exposure to G6, the expression of genes involved in purine biosynthesis and stress responses change in opposite directions while siderophore biosynthesis is downregulated in both species. Our results suggest that different species respond to GuaB inhibition using distinct regulatory programs and possibly explain the different bactericidal kinetics upon GuaB inhibition. The comparison highlights opportunities for developing GuaB inhibitors as novel antibiotics.IMPORTANCE<i>A. baumannii</i> is a priority bacterial pathogen for which development of new antibiotics is urgently needed due to the emergence of multidrug resistance. We recently developed a series of specific inhibitors against GuaB, a bacterial inosine 5'-monophosphate dehydrogenase, and achieved sub-micromolar minimum inhibitory concentrations against <i>A. baumannii</i>. GuaB catalyzes the rate-limiting step of <i>de novo</i> guanine biosynthesis and is highly conserved across bacterial pathogens. This study shows that inhibition of GuaB induced a bacterial morphological profile distinct from that of other classes of antibiotics, highlighting a novel mechanism of action. Moreover, our transcriptomic analysis showed that regulation of <i>de novo</i> purine biosynthesis and stress responses of <i>A. baumannii</i> upon GuaB inhibition differed significantly from that of <i>E. coli</i>.</p>","PeriodicalId":15107,"journal":{"name":"Journal of Bacteriology","volume":" ","pages":"e0010224"},"PeriodicalIF":2.7,"publicationDate":"2024-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11500612/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142132833","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}