Journal of Bacteriology最新文献

{"title":"Impact of protein prenylation inhibition on <i>Mycobacterium leprae</i> viability and IL-1β production in infected macrophages.","authors":"Matheus da Silva Rocha, Antônio Marcos Rodrigues Pereira, Plínio Marcos Freire Dos Santos, André Alves Dias, Melissa Pontes Pereira, Patrícia Sammarco Rosa, Daniele F F Bertoluci, John T Belisle, Fabricio da Mota Ramalho Costa, Cristiana Santos de Macedo, Maria Cristina Vidal Pessolani, Marcia Berrêdo-Pinho","doi":"10.1128/jb.00185-25","DOIUrl":"10.1128/jb.00185-25","url":null,"abstract":"<p><p>Leprosy is a chronic infectious disease caused by <i>Mycobacterium leprae</i> and <i>M. lepromatosis</i>. Brazil consistently ranks among the countries with the highest number of leprosy cases. Data from our group showed that <i>M. leprae</i> upregulates the mevalonate pathway (MP), contributing to the accumulation of cholesterol-ester-enriched lipid droplets in infected macrophages, and that the inhibition of this pathway by statins decreases bacterial intracellular viability. It has already been shown that part of the deleterious effect of statins on <i>M. leprae</i> survival is related to the reduced cholesterol levels, which <i>M. leprae</i> oxidizes to generate reductive power. According to the literature, statins, by inhibiting MP, increase the production of the inflammatory cytokine IL-1β through the negative modulation of the biosynthesis of the isoprenoid geranylgeranyl pyrophosphate (GGPP) and farnesyl pyrophosphate (FPP), which are responsible for protein prenylation. In the present study, we tested the hypothesis that part of the effect of statins on the intracellular viability of <i>M. leprae</i> comes from their impact on IL-1β production via decreased prenylation. We demonstrate that GGPP is essential in macrophage<i>-M. leprae</i> interaction since the MP inhibitors, pamidronate and GGTI-298, which inhibit the enzymes farnesyl pyrophosphate synthase and geranylgeranyl transferase-1, respectively, decreased the intracellular viability of <i>M. leprae</i>, measured by RT-qPCR. MP inhibitors increased IL-1β production by activating the inflammasome, but this effect was reversed with GGPP. IL-1β levels were inversely related to bacterial survival. In conclusion, our findings highlight the potential role of protein geranylgeranylation in <i>M. leprae</i> pathogenesis and suggest new therapy options for leprosy.</p><p><strong>Importance: </strong><i>Mycobacterium leprae</i>, the bacterium that causes leprosy, survives and replicates inside macrophages. Statins, which inhibit the mevalonate pathway, promote bacterial killing in macrophages by affecting cholesterol and isoprenoid production. Cholesterol is crucial for <i>M. leprae</i> survival in macrophages, which explains the microbicidal effect of statins on the bacteria. However, the role of isoprenoid inhibition in statin-induced bacterial killing has not been explored. Isoprenoid groups are added to about 2% of the mammalian proteins, ensuring their proper function. This study focused on geranylgeranyl pyrophosphate (GGPP) and found that inhibiting GGPP formation or protein prenylation in infected macrophages triggered IL-1β production, thereby controlling mycobacterial infection. The findings highlight the importance of protein prenylation in <i>M. leprae</i> and suggest new therapeutic strategies for leprosy.</p>","PeriodicalId":15107,"journal":{"name":"Journal of Bacteriology","volume":" ","pages":"e0018525"},"PeriodicalIF":3.0,"publicationDate":"2025-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12445085/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144955193","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":"Identification of gene targets regulated by the IclR-like regulator SL1344_3500 in <i>Salmonella</i> Typhimurium.","authors":"Thea B Andersen, Nicolas Näpflin, Noemi Santamaria de Souza, Christopher Schubert, Bidong D Nguyen","doi":"10.1128/jb.00054-25","DOIUrl":"10.1128/jb.00054-25","url":null,"abstract":"<p><p>Transcriptional regulation of metabolic operons is important for optimal carbohydrate use and for mitigating the accumulation of toxic intermediates. Here, we characterize <i>SL1344_3500</i>, encoding a putative IclR-like regulator in <i>Salmonella enterica</i> Typhimurium. We present genetic and transcriptional evidence that it regulates the expression of two neighboring operons, one designated here as <i>xynABC</i>, enables utilization of xylonate as a sole carbon source. Furthermore, our findings indicate that <i>SL1344_3500</i> is important for luminal growth in several mouse models, exerting its effects through the suppression of the <i>xynABC</i> operon. Based on the observation that the Δ<i>SL1344_3500</i> deletion can be stably complemented <i>in vivo</i>, we developed a plasmid stabilization strategy. This gene complementation approach shows promise for generating stable gene reporters for long-term colonization experiments.IMPORTANCEUnderstanding transcriptional regulation in <i>Salmonella enterica</i> Typhimurium is crucial for revealing how enteric pathogens optimize metabolism to compete with commensals in the gut. SL1344_3500, an IclR-like transcriptional regulator controlling genes linked to sugar acid metabolism, is essential for luminal growth in mouse models through gene suppression and represents a potential target for antimicrobial development. Based on these observations, we developed stable reporter plasmids that use gene complementation of SL1344_3500 to prevent plasmid loss during long-term <i>in vivo</i> studies.</p>","PeriodicalId":15107,"journal":{"name":"Journal of Bacteriology","volume":" ","pages":"e0005425"},"PeriodicalIF":3.0,"publicationDate":"2025-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12445098/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144955185","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":"Deciphering the function of Com_YlbF domain-containing proteins in <i>Staphylococcus aureus</i>.","authors":"Zayda-Lorena Corredor-Rozo, Ricaurte Marquez-Ortiz, Myriam L Velandia-Romero, Deisy Abril, Johana Madroñero, Luisa F Prada, Natasha Vanegas-Gomez, Begoña García, Maite Echeverz, María-Angelica Calderón-Peláez, Jacqueline Chaparro-Olaya, Liliana Morales, Carlos Nieto-Clavijo, Javier Escobar-Perez","doi":"10.1128/jb.00061-25","DOIUrl":"10.1128/jb.00061-25","url":null,"abstract":"<p><p>The Com_YlbF domain-containing proteins inhibit sporulation, competition, and biofilm formation by affecting the activity of ribonuclease RNase-Y in <i>Bacillus subtilis</i>. Similar Com_YlbF proteins are found in <i>Staphylococcus aureus</i>, but their function is yet to be determined. This study investigates the role of Com_YlbF domain-containing proteins (Qrp/YheA, YmcA, and YlbF) in <i>S. aureus</i> by evaluating the impact of <i>qrp/yheA</i>, <i>ymcA</i>, and <i>ylbF</i> gene deletion on biofilm formation, PIA/PNAG production, and hemolytic capacity. It was found that deletion of the three <i>qrp/yheA</i>, <i>ymcA</i>, and <i>ylbF</i> genes in <i>S. aureus</i> produced a decrease in biofilm formation, a slight decrease in PIA/PNAG production, and a decrease in its hemolytic capacity. Global transcriptional analysis in the mutant strain showed dysregulation of several genes associated with pathogenesis, most notably a decreased expression of the <i>agrA</i> gene (quorum sensing system), the <i>delta</i>, <i>alpha</i>, and <i>gamma</i> hemolysins, as well as the <i>sdrC</i> genes and <i>eap/map</i> (adhesion proteins) genes. It also showed an attenuation of virulence, manifesting as enhanced survival among <i>Galleria mellonella</i> larvae and BALB/c mice, possibly associated due to disrupted RNase-Y activity when the <i>qrp/yheA</i>, <i>ymcA</i>, and <i>ylbF</i> are deleted. In conclusion, this work supports the hypothesis that this new family of proteins containing a Com_YlbF domain is involved in the regulation of genes related to biofilm formation, hemolysis, and virulence in <i>S. aureus</i> through a change in RNase-Y activity.IMPORTANCEThe Com_YlbF proteins are a group of small proteins identified in some Gram-positive bacteria whose function has not been described, but whose deletion has been related to pleiotropic effects in <i>Bacillus subtilis</i> (reduction of biofilm ability, sporulation, and competence). However, the role of these proteins in <i>S. aureus</i> has been little studied. This study shows the importance of the Com_YlbF protein family in <i>S. aureus</i> involved in biofilm formation and hemolysis. The phenotypes could be explained by an alteration of the enzymatic activity of the endoribonuclease RNase-Y, resulting in reduced secretion of virulence factors. These findings represent a significant step forward in understanding the modulation of pathogenesis and virulence in <i>S. aureus</i>.</p>","PeriodicalId":15107,"journal":{"name":"Journal of Bacteriology","volume":" ","pages":"e0006125"},"PeriodicalIF":3.0,"publicationDate":"2025-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12445100/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144873335","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":"Correction for Staehelin et al., \"Exo-Oligosaccharides of <i>Rhizobium</i> sp. Strain NGR234 Are Required for Symbiosis with Various Legumes\".","authors":"Christian Staehelin, Lennart S Forsberg, Wim D'Haeze, Mu-Yun Gao, Russell W Carlson, Zhi-Ping Xie, Brett J Pellock, Kathryn M Jones, Graham C Walker, Wolfgang R Streit, William J Broughton","doi":"10.1128/jb.00157-25","DOIUrl":"10.1128/jb.00157-25","url":null,"abstract":"","PeriodicalId":15107,"journal":{"name":"Journal of Bacteriology","volume":" ","pages":"e0015725"},"PeriodicalIF":3.0,"publicationDate":"2025-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12445091/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144955260","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":"AnaToc75 (Alr2269) mediates calcium uptake across the outer membrane in <i>Anabaena</i> sp. PCC 7120.","authors":"Xiaoying Jiang, Hong Gao, Yanling Dong, Jianxin Tang, Shuiling Ji, Xudong Xu","doi":"10.1128/jb.00291-25","DOIUrl":"https://doi.org/10.1128/jb.00291-25","url":null,"abstract":"<p><p>It has been a long-standing notion that cyanobacterial Omp85 proteins are essential because of their role in insertion of β-barrel proteins into the outer membrane (OM). Alr2269 from <i>Anabaena</i> sp. PCC 7120 is such an Omp85 protein, structurally related to the Toc75 channel of the translocon at the outer envelope membrane of chloroplasts but is actually non-essential to <i>Anabaena</i> under calcium-replete conditions. In a completely segregated <i>alr2269</i>-null mutant, a predicted S-layer protein, All3983, and many β-barrel proteins in the OM were upregulated compared with the wild type. By removal of each component from the medium, Ca²⁺ deficiency was identified to be the key environmental signal for upregulation of P<i>_all3983-luxAB</i> in the mutant. Assays of ⁴⁵Ca²⁺ uptake in the wild type and the mutant indicated that Alr2269 is a relatively specific channel for transport of Ca²⁺ across the OM in low-Ca²⁺ medium. Accordingly, inactivation of <i>alr2269</i> greatly reduced the growth under Ca²⁺-limiting conditions, while the complemented strain grew as the wild type. In low-Mg²⁺ medium, however, the <i>alr2269</i> mutant showed only a slight difference in growth from the wild type. These results establish Alr2269 (AnaToc75) as the main channel for Ca²⁺ uptake across the OM of <i>Anabaena</i> in low-Ca²⁺ environments.IMPORTANCECa²⁺ is required for photosynthesis and various cellular activities in cyanobacteria, but Ca²⁺ uptake, in particular how Ca²⁺ is transported across the outer membrane, has been barely investigated in cyanobacterial species. In this study, we found that a cyanobacterial Toc75 homolog is not necessarily essential for protein integration into the outer membrane as was thought before but instead is required for Ca²⁺ uptake in low-Ca²⁺ environments. This finding not only establishes a Ca²⁺ channel across the outer membrane of cyanobacteria but also provides an example of additional functions for Omp85 proteins.</p>","PeriodicalId":15107,"journal":{"name":"Journal of Bacteriology","volume":" ","pages":"e0029125"},"PeriodicalIF":3.0,"publicationDate":"2025-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145080757","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Protein trafficking across the cell envelope of gram-positive bacteria.","authors":"Dipanwita Bhattacharya, Ran Zhang, Wenqi Yu","doi":"10.1128/jb.00100-25","DOIUrl":"10.1128/jb.00100-25","url":null,"abstract":"<p><p>Protein trafficking from the cytosol to specific sites of action is a fundamental process for bacterial survival and growth. In the monoderm gram-positive bacteria, this process involves traversing the cytoplasmic membrane, the membrane-wall interface, and the thick cell wall. With a primary focus on <i>Bacillus subtilis</i> and <i>Staphylococcus aureus</i>, this minireview aims to provide an overview and mechanistic insights into (i) protein translocation across the cytoplasmic membrane via the Sec system, (ii) protein processing by chaperones and proteases in the membrane-wall interface, and (iii) protein attachment to the cell wall and translocation across the cell wall. Furthermore, we emphasize recent advancements in spatial regulation of protein translocation systems. By examining conserved and unique mechanistic features, this review aims to offer a systematic understanding of protein trafficking in gram-positive bacteria.</p>","PeriodicalId":15107,"journal":{"name":"Journal of Bacteriology","volume":" ","pages":"e0010025"},"PeriodicalIF":3.0,"publicationDate":"2025-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12445088/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144816727","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 SWIB domain-containing DNA topoisomerase I of <i>Chlamydia trachomatis</i> mediates DNA relaxation.","authors":"Li Shen, Abigail R Swoboda, Caitlynn Diggs, Shomita Ferdous, Andrew Terrebonne, Amanda Santos, Noel Wolf, Luis Lorenzo Carvajal, Guangming Zhong, Scot P Ouellette, Yuk-Ching Tse-Dinh","doi":"10.1128/jb.00190-25","DOIUrl":"10.1128/jb.00190-25","url":null,"abstract":"<p><p><i>Chlamydia trachomatis</i> has a DNA topoisomerase I with a unique C-terminal domain (CTD) homologous to eukaryotic SWIB domains. This study focused on determining the function of the SWIB domain-containing TopA from <i>C. trachomatis</i> (CtTopA). We demonstrated that, despite the lack of sequence similarity at the CTDs between CtTopA and TopA from <i>Escherichia coli</i> (EcTopA), full-length CtTopA removed negative DNA supercoils <i>in vitro</i> and complemented the growth defect of a <i>topA</i> mutant of <i>E. coli</i>. CtTopA is less processive in DNA relaxation than EcTopA in dose-response and time course studies. An antibody generated against the SWIB domain of CtTopA specifically recognized CtTopA but not EcTopA or <i>Mycobacterium tuberculosis</i> TopA, consistent with the sequence differences in their CTDs. The endogenous CtTopA protein is expressed at a relatively high level during the middle and late developmental stages of <i>C. trachomatis</i>. Overexpressing a <i>topA</i> mutant allele lacking the SWIB domain in <i>C. trachomatis</i> resulted in slow growth when host protein synthesis was inhibited. These data suggest that productive infection of <i>C. trachomatis</i> requires functional SWIB domain-containing CtTopA and <i>de novo</i> host protein synthesis. Because SWIB domain-containing CtTopAs are not found in prokaryotes beyond <i>Chlamydia</i> spp., our work suggests an important function of the SWIB domain on CtTopA activity during <i>C. trachomatis</i> infection.IMPORTANCE<i>Chlamydia trachomatis</i> is a medically important bacterial pathogen that is responsible for the most prevalent bacterial sexually transmitted infection. Bioinformatics, genetics, and biochemical analyses have established that the presence of a SWIB domain in CtTopA is relevant to chlamydial physiology. Our findings also underline the mechanistic diversity among the family of TopAs that are likely driven by pathogen-specific adaptations.</p>","PeriodicalId":15107,"journal":{"name":"Journal of Bacteriology","volume":" ","pages":"e0019025"},"PeriodicalIF":3.0,"publicationDate":"2025-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12445093/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144821501","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":"Opposing roles for iron transport systems in gallium tolerance in extraintestinal pathogenic <i>Escherichia coli</i>.","authors":"Nagama Parveen, Seth Durrant, Michael A Olson, Emily P Shakespear, Trevor R Jones, Rachael J David Prince, Eric Wilson, David L Erickson","doi":"10.1128/jb.00349-25","DOIUrl":"https://doi.org/10.1128/jb.00349-25","url":null,"abstract":"<p><p>Gallium is a promising antibacterial candidate because it displaces iron atoms inside bacterial cells but does not undergo redox cycling. It inhibits growth by disrupting essential iron-dependent processes. However, <i>Escherichia coli</i> are naturally less sensitive to gallium than many other bacteria, and the mechanisms that control gallium tolerance are not completely understood. We performed a genome-wide transposon sequencing (TnSeq) screen to identify genes important for the survival of an extraintestinal pathogenic <i>E. coli</i> isolate (M12) in gallium nitrate. The TnSeq results indicated that inactivation of enterobactin siderophore-related genes (<i>entS</i>, <i>fepD</i>, <i>fes</i>, and <i>fepB</i>) enhances bacterial survival in gallium, while disrupting the ferric dicitrate transport system increases susceptibility. We validated these findings through targeted gene knockouts and gallium sensitivity experiments. Our findings suggest that enterobactin can complex with gallium for cellular uptake, but that the ferric citrate receptor FecA can discriminate between gallium citrate and iron citrate. Expression of <i>fecA</i> increased with gallium exposure, showing that gallium induces FecA-mediated iron uptake. Gallium also increased intracellular levels of manganese in the Δ<i>fecA</i> strain. Supplementation with iron or manganese restored growth of M12 Δ<i>fecA</i> in gallium, suggesting that gallium sensitivity is linked to both iron starvation and oxidative stress. As the ferric dicitrate transport system is an important virulence factor in several extraintestinal infection sites, our results suggest that targeting FecA may increase <i>E. coli</i> susceptibility to gallium while also suppressing virulence.IMPORTANCE<i>Escherichia coli</i> extraintestinal infections that are resistant to traditional antibiotics are associated with more deaths than any other species. Gallium-based therapies may represent a non-antibiotic approach for treating extraintestinal pathogenic <i>E. coli</i> strains that affect both humans and animals. Our results are significant as they show that the enterobactin siderophore and the ferric dicitrate iron transport systems expressed by these bacteria have opposing roles in <i>E. coli</i> gallium sensitivity. These findings could be leveraged to enhance the efficacy of gallium therapeutics.</p>","PeriodicalId":15107,"journal":{"name":"Journal of Bacteriology","volume":" ","pages":"e0034925"},"PeriodicalIF":3.0,"publicationDate":"2025-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145080759","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":"Impact of flagellar filament length on <i>Campylobacter jejuni</i> for colonization and flagellar-dependent phenotypes.","authors":"Alexis A Waller, Deborah A Ribardo, David R Hendrixson","doi":"10.1128/jb.00199-25","DOIUrl":"10.1128/jb.00199-25","url":null,"abstract":"<p><p>Many bacteria produce flagella to swim and navigate through environments. Depending on the species, flagella are beneficial for other activities such as sensing surfaces to initiate biofilm development, secretion of specific proteins, and interactions with hosts to promote colonization or pathogenesis of disease. The extracellular region of the flagellum consists mostly of the filament, which is required for many flagellar-dependent activities. The length of the filament varies across bacterial flagellates and even stochastically within a clonal population, but it is unknown whether or how altering filament length impacts flagellar function for motility and other activities. We recently discovered a mechanism by which FlaG of <i>Campylobacter jejuni</i> and other polarly flagellated bacteria controls flagellar filament length so that these species produce shorter filaments than their peritrichous counterparts. We exploited a set of isogenic <i>C. jejuni</i> mutants producing significantly longer and shorter flagellar filaments than WT to assess the impact of filament length on activities of <i>C. jejuni</i> necessary for commensal colonization of a natural host. We found that production of shorter flagellar filaments slows swimming velocity and hinders intestinal colonization of chickens. Although production of shorter and longer flagellar filaments differently impacted cellular autoagglutination, only a subtle impact on biofilm formation was observed. We also acquired evidence that FlaG itself may impact biofilm development, suggesting that FlaG may have another function besides controlling flagellar filament length. Overall, our data suggest that shortening flagellar filaments has a greater impact on flagellar-dependent activities of <i>C. jejuni</i> than producing overly elongated filaments.</p><p><strong>Importance: </strong>Flagella and flagellar motility are important to propel many bacteria through environments, biofilm formation, and infection of respective hosts. Most often, the importance of flagella for a species has been assessed with mutants lacking flagella altogether or only the extracellular filament while retaining the basal body. We addressed whether altering filament length impacts flagellar-dependent activities for host colonization. We exploited isogenic <i>Campylobacter jejuni</i> mutants that synthesize longer and shorter filaments on average relative to WT to find that production of shorter filaments had greater negative impacts on motility, autoagglutination, and commensal colonization compared to bacteria that produce elongated filaments. Our findings suggest that polar flagellates may produce a flagellar filament of minimal length to achieve flagellar functions and preserve fitness.</p>","PeriodicalId":15107,"journal":{"name":"Journal of Bacteriology","volume":" ","pages":"e0019925"},"PeriodicalIF":3.0,"publicationDate":"2025-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12445086/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144816725","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":"Effects of low intracellular glutathione and CbrA-CbrB-Crc signaling on methylglyoxal sensitivity in <i>Pseudomonas aeruginosa</i> LasR-deficient mutants.","authors":"Ana Altamirano, Marina Ruzic, Anna E Cryan, Deborah A Hogan","doi":"10.1128/jb.00394-24","DOIUrl":"10.1128/jb.00394-24","url":null,"abstract":"<p><p><i>Pseudomonas aeruginosa</i>, which causes many types of infections, often has loss-of-function mutations in the gene encoding LasR, a transcription factor involved in quorum sensing. Here, we report that LasR- strains are more sensitive to the electrophile methylglyoxal (MGO), which is produced by many cells, including those involved in immune defense. MGO, due to its high reactivity, must be rapidly detoxified to prevent the formation of damaging adducts on macromolecules. GloA3 is a GSH-dependent MGO glyoxalase involved in MGO detoxification, and we found that intracellular GSH levels were lower in ∆<i>lasR</i> strains, as measured by multiple methods. Furthermore, we show that exogenous GSH and GloA3 overexpression both enhance GloA3-dependent MGO resistance, particularly in a ∆<i>lasR</i> mutant. Previous reports suggest that one factor that contributes to the selection for LasR- strains is a growth advantage resulting from increased activity of the CbrAB two-component system, which lowers the Crc-mediated translational repression of many RNAs. Genetic data presented here suggest that low Crc activity leads to increased MGO sensitivity in LasR- strains but not through effects on GSH or GloA3. Together, these data suggest that LasR- strains are more sensitive to MGO due to multiple factors, including lower intracellular levels of GSH and decreased Crc activity, and that these factors may represent fitness trade-offs for LasR- strains.IMPORTANCEMethylglyoxal (MGO) is a highly reactive metabolite detected in various disease states, including those involving <i>Pseudomonas aeruginosa</i>. <i>P. aeruginosa</i> requires the glutathione-dependent glyoxalase enzyme GloA3 for MGO resistance. This study reveals that <i>P. aeruginosa</i> strains with mutations in the gene encoding the transcription factor LasR, commonly found in clinical isolates, are more sensitive to MGO due to lower intracellular glutathione levels and high activity of the CbrAB-Crc regulatory pathway. Thus, sensitivity to MGO and other electrophiles may represent a trade-off for <i>P. aeruginosa</i> in infections.</p>","PeriodicalId":15107,"journal":{"name":"Journal of Bacteriology","volume":" ","pages":"e0039424"},"PeriodicalIF":3.0,"publicationDate":"2025-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145080728","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}