FEMS microbes最新文献

{"title":"Two new <i>Vibrio diazotrophicus</i> strains isolated from deep-sea hydrothermal iron-rich microbial mats display unexpected metabolic capacities.","authors":"Ludivine Michaudet, Eva Pouder, Nadège Bienvenu, Xavier Philippon, Marion Ménec, Ouafae Rouxel, Marie-Anne Cambon, Dominique Hervio-Heath, Claire Geslin, Karine Alain, Sophie Mieszkin","doi":"10.1093/femsmc/xtag030","DOIUrl":"10.1093/femsmc/xtag030","url":null,"abstract":"<p><p>Iron-rich microbial mats at low-temperature sites in deep-sea hydrothermal environments make a significant contribution to element cycling, especially the iron cycle. From these mats collected at the MIR zone (Trans-Atlantic Geotraverse hydrothermal field, Mid-Atlantic Ridge), enrichment cultures were performed to isolate strains involved in iron metabolism. Two strains, affiliated to <i>Vibrio diazotrophicus</i> (HER2-O and HER2-R), were isolated from this environment and might be able to oxidize iron under autotrophic and anaerobic or microaerophilic conditions, in addition to grow under organoheterotrophic conditions. In particular, genomic analyses revealed the presence of a <i>c₄</i> -type cytochrome (<i>cyc1</i>) that could be involved in electron transfer in the Fe(II)-oxidation pathway and a complete inorganic carbon fixation pathway (reductive glycine pathway), arguing in favor of growth based on autotrophic metabolism, using iron as an energy source. Prophages were identified in both genomes. <i>Caudoviricetes</i>-type virus morphotypes were evidenced by direct observations during growth under organoheterotrophic conditions. Genes providing metabolic adaptations to deep-sea hydrothermal vent conditions were also identified and could confer an ecological advantage to these two novel strains to thrive and compete effectively in metal-rich deep-sea environments. Their unexpected abilities regarding their potential to oxidize Fe(II), in addition to their physiological capacities, may help to explain their presence in iron-rich microbial mats.</p>","PeriodicalId":73024,"journal":{"name":"FEMS microbes","volume":"7 ","pages":"xtag030"},"PeriodicalIF":4.2,"publicationDate":"2026-06-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13270974/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148273915","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Elucidating the interplay between intracellular manganese-iron-ratio and radiotolerance across all domains of life.","authors":"Kristina Beblo-Vranesevic, Hector Palomeque-Dominguez, Tommaso Zaccaria, Robert Reichelt, Dina Grohmann, Jessica A Stammeier, Petra Rettberg","doi":"10.1093/femsmc/xtag029","DOIUrl":"10.1093/femsmc/xtag029","url":null,"abstract":"<p><p>Exposure to natural or artificial ionizing radiation induces direct damage to intracellular macromolecules and promotes the formation of reactive oxygen species, which can further amplify cellular injury. Although many organisms tolerate high radiation doses, the basis of this resilience is not fully understood. A proposed determinant is the intracellular manganese-to-iron ratio (Mn/Fe-ratio), thought to reduce oxidative stress. To evaluate its relevance, Mn and Fe levels were measured in 19 archaeal, bacterial, and two eukaryotic yeast species and compared these values with their survivability after ionizing radiation exposure. There was no consistent relationship between Mn/Fe-ratios and radiation tolerance across this broad phylogenetic range. Integrating our results with prior studies suggests that while elevated Mn/Fe-ratios may contribute to exceptional resistance in certain specialized microorganisms, the ratio is not a reliable, universal predictor of survivability. These findings highlight the multifactorial nature of radiation tolerance and indicate that other processes (e.g. DNA repair mechanisms, antioxidant defenses, and metabolic adaptations) likely play central roles. By clarifying the limitations of Mn/Fe-ratio as a generalizable marker, this study provides a more nuanced understanding of the biochemical determinants of radiation resistance and informs future research into mechanisms of cellular resilience under extreme stress.</p>","PeriodicalId":73024,"journal":{"name":"FEMS microbes","volume":"7 ","pages":"xtag029"},"PeriodicalIF":4.2,"publicationDate":"2026-05-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13251893/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148229507","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Development of a clinical scoring tool using machine-learning prediction of monospot positivity in suspected infectious mononucleosis.","authors":"Dhruv Patel, James Morris, Francesca Speck, Matthew Flynn","doi":"10.1093/femsmc/xtag027","DOIUrl":"10.1093/femsmc/xtag027","url":null,"abstract":"<p><p>Infectious mononucleosis is clinically difficult to distinguish from bacterial causes of tonsillitis/pharyngitis. First-line investigations include monospot testing, despite 63% sensitivity in certain cohorts. Therefore, national recommendations include repeating an initial negative monospot within five to seven days. A point-of-care clinical scoring tool could improve clinical outcomes, increase diagnostic accuracy and reduce unnecessary testing. We conducted a retrospective cohort study at Luton and Dunstable University Hospital including patients aged 15-24 presenting with sore throat, lymphadenopathy or fever between 01/01/2021 and 31/01/2024 who underwent monospot testing. Extracted data included demographics, observations, and laboratory results. Patients were randomly split into training (80%) and testing (20%) cohorts. Eleven parameters were used to develop four predictive models; classical multivariate logistic regression, machine-learning logistic regression with LIBLINEAR approximation, machine-learning decision tree classifier, and a simplified clinical risk-stratification model from machine-learning methods. Total of 278 presentations from 264 patients were included. The machine-learning decision tree classifier demonstrated superior performance, achieving 100% sensitivity, 98.0% specificity, and 98.2% diagnostic accuracy using only three parameters: lymphocyte count, neutrophil count, and alanine aminotransferase. The simplified clinical risk-stratification model demonstrated 83.3% sensitivity, 98.0% specificity, and overall 96.4% accuracy. All four models represent potential methods for developing clinical tools to predict monospot positivity. Our risk-stratification model showed significant promise as an easily memorisable, point-of-care clinical scoring tool. Using this, we propose an alternative diagnostic pathway with early counselling and de-escalation of antibiotics in high-risk cases, and reduced testing in low-risk cases; reducing population-level morbidity and epidemiological spread, whilst improving diagnostic accuracy and conserving resources.</p>","PeriodicalId":73024,"journal":{"name":"FEMS microbes","volume":"7 ","pages":"xtag027"},"PeriodicalIF":4.2,"publicationDate":"2026-05-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13595444/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149027190","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Maltose aids in the growth of <i>Salmonella</i> Typhimurium in nitrogen-deficient conditions.","authors":"Kirti Parmar, Yogyta Kumari, Muralidhar Nayak M, Kapudeep Karmakar, Sumanta Bagchi, Dipshikha Chakravortty","doi":"10.1093/femsmc/xtag028","DOIUrl":"10.1093/femsmc/xtag028","url":null,"abstract":"<p><p>Enteric pathogens, such as <i>Salmonella</i>, encounter uncertain nutrients in both the host and the environment. Nutrients such as carbon and nitrogen are essential for growth, and when these nutrients are limited, bacteria have developed various mechanisms to overcome stress and thrive in nutrient-rich environments. In this study, we investigated the role of the disaccharide sugar maltose in the growth and pathogenicity of <i>Salmonella</i> Typhimurium (STM) under nitrogen-deficient culture conditions. Throughout the study, we used Burk's medium to mimic nitrogen-deficient conditions. STM growth in Burk's medium was minimal, and maltose supplementation enhanced STM growth in both liquid and solid Burk's media. The STM grown in Burk's medium had a reduced bacterial cell length, which increased upon the addition of maltose and became comparable to that of LB-grown STM WT. Growth was dependent on the NtrBC two-component system and sigma factor RpoE. Deletion of <i>ntrB</i> and <i>rpoE</i> significantly reduced the growth in Burk's medium during the log phase. <i>Salmonella</i> grown in Burk's medium with maltose had reduced invasion in Caco-2 cells, phagocytosis in RAW 264.7 macrophages, and organ burden in C57BL/6 mice. Our findings revealed the role of maltose in enhancing the growth and length of <i>Salmonella</i> under nitrogen-deficient conditions. However, <i>Salmonella</i> grown in Burk's medium with maltose is defective in pathogenesis.</p>","PeriodicalId":73024,"journal":{"name":"FEMS microbes","volume":"7 ","pages":"xtag028"},"PeriodicalIF":4.2,"publicationDate":"2026-05-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13347741/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148426961","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Diversity and selected functional traits of microbiota associated with traditional dried plant foods from South African informal markets.","authors":"Birgit Wassermann, Isabella Kögl, Jarishma K Gokul, Wisnu Adi Wicaksono, Matthias Schweitzer, Lise Korsten, Gabriele Berg","doi":"10.1093/femsmc/xtag026","DOIUrl":"10.1093/femsmc/xtag026","url":null,"abstract":"<p><p>Traditional plant-based products provide nutritional benefits and support cultural heritage; however, their sale in urban informal markets raises potential food safety considerations. We characterized the microbiota of five traditional dried plant products (baobab, masau, nyii, dinawa, and lude) obtained from three informal markets in South Africa (<i>n</i> = 51 samples) using 16S rRNA gene sequencing and quantitative real-time PCR; bacterial isolates (<i>n</i> = 87) were further evaluated using selected phenotypic assays. Bacterial abundance and composition varied across products and vendors. Baobab exhibited the highest microbial richness (1460 ASVs) but relatively low bacterial loads (10⁶ 16S rRNA gene copies g^-1), whereas dried leafy greens showed the lowest richness (470 ASVs) but the highest bacterial abundance (10⁹ copies g^-1). Across products, higher bacterial diversity correlated with genera such as <i>Bifidobacterium</i> and <i>Prevotella</i>, while higher bacterial abundance correlated with genera such as <i>Salmonella, Vibrio</i>, and <i>Acinetobacter</i>. Notably, health implications of detected taxa cannot be inferred from genus-level identification based on 16S rRNA gene sequencing. Phenotypic traits observed among selected isolates included growth in the presence of several antibiotics (particularly sulfadiazine and ampicillin), protease activity, and inhibition of indicator strains under laboratory conditions. Overall, traditional dried plant foods harbor diverse microbial communities shaped by plant characteristics and vendor-related practices, highlighting the importance of improved handling and drying practices.</p>","PeriodicalId":73024,"journal":{"name":"FEMS microbes","volume":"7 ","pages":"xtag026"},"PeriodicalIF":4.2,"publicationDate":"2026-05-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13220767/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148139925","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"<i>Phytophthora</i> root rot induces compositional and functional changes in avocado rhizosphere bacterial communities.","authors":"Rosaura G Alfaro-García, Pablo Vargas-Mejía, Violeta Patiño-Conde, Eria A Rebollar, José A Guerrero-Analco, Julio Vega-Arreguín, Frédérique Reverchon, Alfonso Méndez-Bravo","doi":"10.1093/femsmc/xtag025","DOIUrl":"10.1093/femsmc/xtag025","url":null,"abstract":"<p><p>Understanding how plant pathogens modulate the rhizosphere microbiota is essential to integrated disease management. Here, the compositional and functional shifts in the avocado rhizosphere bacteriome induced by <i>Phytophthora cinnamomi</i> were assessed to identify bacterial taxa enriched in the symptomatic condition and elucidate the microbial functions modulated by the infection. Metabarcoding and metatranscriptomics analyses revealed that <i>Phytophthora</i> root rot (PRR) induced compositional shifts in bacterial communities, leading to the enrichment of members of MND1, RB41, and <i>Nitrospira</i>. Functional analysis showed that this enrichment might be due to the release of nutrients following root rot, as carbohydrate metabolism was stimulated in rhizobacterial communities of infected trees. Moreover, the relative abundance of transcripts from genes associated with stress response and cell signaling increased in some of the most active genera in the rhizosphere of PRR-symptomatic trees, suggesting their potential to mitigate the adverse effects of infection. These findings highlight the need to combine compositional and functional microbiome data to differentiate between taxa attracted by nutrient release and those contributing to the plant defense. The interactions of beneficial bacterial taxa with the pathogen should be further studied, as they may constitute promising biocontrol agents.</p>","PeriodicalId":73024,"journal":{"name":"FEMS microbes","volume":"7 ","pages":"xtag025"},"PeriodicalIF":4.2,"publicationDate":"2026-05-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13220768/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148139978","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Indigenous microbiology: Why Indigenous knowledge matters in microbial science.","authors":"Francyeli Araújo Silva, Ruthchelly Tavares da Silva, Nikki Harcourt, Eva Biggs, Marciane Magnani","doi":"10.1093/femsmc/xtag024","DOIUrl":"10.1093/femsmc/xtag024","url":null,"abstract":"<p><p>Indigenous knowledge has long engaged with microorganisms through relationships with environment, food, and health, yet these understandings remain marginal in mainstream microbiology. In this article, we argue that Indigenous microbiology offers a broader framework for microbial science by placing microorganisms within ecological, cultural, and ecosystem-specific relationships. This perspective is relevant to current challenges in sustainable agriculture, food security, and antimicrobial resistance. Drawing on examples from environmental management, traditional fermented foods, and therapeutic practices, we show that Indigenous knowledge can deepen microbiome research and contribute to developing healthy and sustainable strategies. Indigenous microbiology should not be treated as an informal add-on to existing science, but as a valuable framework for asking better questions about microbial life and its role in human and environmental wellbeing.</p>","PeriodicalId":73024,"journal":{"name":"FEMS microbes","volume":"7 ","pages":"xtag024"},"PeriodicalIF":4.2,"publicationDate":"2026-05-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13178256/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147966230","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Microbial succession and hydrocarbon-degrading potential in Arctic sea ice exposed to dispersed crude oil and chemical dispersant.","authors":"Hiie Nõlvak, Nga Phuong Dang, Marika Truu, Angela Peeb, Arun Kumar Devarajan, Chris Petrich, Megan O'Sadnick, Kertu Tiirik, Jaak Truu","doi":"10.1093/femsmc/xtag022","DOIUrl":"10.1093/femsmc/xtag022","url":null,"abstract":"<p><p>The increasing oil exploration and transport activities in the Arctic amplify the risk of oil spills in ice-containing marine environments. Chemical dispersants, intended to promote oil biodegradation by breaking hydrocarbons into small droplets, are potential tools in cold marine oil spill mitigation; however, their fate and effectiveness within sea ice remain uncertain. This study examined the influence of dispersed crude oil and the chemical dispersant (FinasolOSR 51) on microbial community dynamics and hydrocarbon-degrading potential compared to clean ice during an 89-day sea-ice mesocosm experiment using shotgun metagenomics and metagenome-assembled genomes. Dispersant addition markedly reshaped microbial communities in both dispersed-oil and dispersant containing ice, causing similar shifts toward psychrophilic hydrocarbon degraders such as <i>Oleispira, Bermanella</i>, and <i>Pseudoalteromonas</i>. Although aliphatic hydrocarbon degradation genes were enriched, several dominant taxa exhibited limited hydrocarbon metabolic capacity yet possessed extensive stress-response traits. Oil hydrocarbon loss in ice remained modest despite the presence of degraders, likely due to the very low microbial abundance. These findings demonstrate that dispersants can strongly shape microbial communities in Arctic sea ice, without necessarily enhancing the biodegradation of oil hydrocarbons. This highlights the need for careful evaluation of dispersants as remediation tools in ice-containing Arctic marine environments.</p>","PeriodicalId":73024,"journal":{"name":"FEMS microbes","volume":"7 ","pages":"xtag022"},"PeriodicalIF":4.2,"publicationDate":"2026-04-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13159726/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147936091","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Spontaneous TisB toxin expression modulates <i>Escherichia coli</i> metabolic adaptation during growth transitions.","authors":"Jose Ibarra, Marie-Florence Bredèche, Lena Brezovnik, Thierry Oms, Laurence Van Melderen, Ivan Matic","doi":"10.1093/femsmc/xtag023","DOIUrl":"10.1093/femsmc/xtag023","url":null,"abstract":"<p><p><i>Escherichia coli</i> TisB/IstR1 is a type I toxin-antitoxin system. The TisB toxin targets the inner membrane and disrupts the proton motive force (PMF). Under normal growth conditions, <i>tisB</i> transcription is repressed by the LexA SOS repressor, and IstR1 blocks its translation. DNA damage lifts LexA repression, allowing <i>tisB</i> mRNA to overcome IstR1 inhibition and produce TisB. Although spontaneous <i>tisB</i> expression has been reported, its physiological significance remains unclear. We show that <i>tisB</i> is spontaneously induced and TisB is synthesized during the transition to stationary phase, coinciding with decreased LexA repression and a transient decline in <i>istR1</i> promoter activity. Deletion of <i>tisB</i> does not affect exponential growth but delays entry into and exit from stationary phase, reduces fitness under nutrient limitation and alkaline pH, and impairs stringent response induction, intracellular pH homeostasis, and glycogen accumulation-phenotypes consistent with metabolic dysregulation. These findings indicate that low-level spontaneous TisB production modulates metabolism during the transition to stationary phase. By collapsing the PMF, TisB attenuates nutrient uptake and promotes early stringent-response-driven dormancy before nutrient exhaustion. Our results reveal a physiological role for TisB, positioning it as a metabolic rheostat that fine-tunes adaptation to environmental fluctuations.</p>","PeriodicalId":73024,"journal":{"name":"FEMS microbes","volume":"7 ","pages":"xtag023"},"PeriodicalIF":4.2,"publicationDate":"2026-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13159721/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147936077","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Roles of three carbonic anhydrases in <i>in vitro</i> growth, pH homeostasis, metabolism, and intracellular survival of <i>Neisseria gonorrhoeae</i>.","authors":"Sanjay V Alokabandara, Hsin-Wen Liang, Aloka B Bandara","doi":"10.1093/femsmc/xtag021","DOIUrl":"10.1093/femsmc/xtag021","url":null,"abstract":"&lt;p&gt;&lt;p&gt;In many bacterial species, carbonic anhydrases (CAs) have been shown to play crucial roles in metabolism, cellular pH homeostasis, growth, and/or pathogenicity. Thus, these enzymes are considered as vital targets of drug development. We investigated the importance of CAs to growth, cellular metabolism, pH homeostasis, and intracellular survival of &lt;i&gt;Neisseria gonorrhoeae&lt;/i&gt;. BLAST searches of &lt;i&gt;N. gonorrhoeae&lt;/i&gt; genome sequence revealed the presence of three genes respectively homologous to αCA, βCA, and γCA genes of other bacteria. The putative αCA protein of &lt;i&gt;N. gonorrhoeae&lt;/i&gt; was found to localize to the periplasm, whereas the other two proteins were predicted to reside in the cytoplasm. All three CAs of &lt;i&gt;N. gonorrhoeae&lt;/i&gt; shared up to 99% identity with CAs of other bacteria. Three isogenic mutants were constructed by disrupting the αCA, βCA, and γCA genes. The mutants were complemented by reincorporating the disrupted CA genes into each of the mutants. All three CA mutants were similar to the parent &lt;i&gt;N. gonorrhoeae&lt;/i&gt; in terms of their growth at 5% CO&lt;sub&gt;2&lt;/sub&gt;. Nevertheless, unlike the parent or the other CA mutants, the ΔβCA mutant failed to grow at ambient air or 2% or 3% CO&lt;sub&gt;2&lt;/sub&gt;, highlighting the importance of the βCA for CO&lt;sub&gt;2&lt;/sub&gt; hydration in decreased CO&lt;sub&gt;2&lt;/sub&gt; environments. The pH of the culture medium decreased during proliferation of &lt;i&gt;N. gonorrhoeae&lt;/i&gt; cells, nevertheless, the least decline of pH was observed in the ΔβCA mutant culture. These findings suggest that &lt;i&gt;N. gonorrhoeae&lt;/i&gt; prefers slightly acidic growth environment and βCA is important for pH homeostasis. Acetyl-CoA, which is a substrate for Malonyl-CoA biosynthesis in cell, was recovered in relatively increased amounts from the ΔαCA and ΔβCA mutant cells, underscoring a possible relationship between the αCA and βCA functions and cellular metabolism. Relative to the parent strain, the ΔαCA and ΔβCA mutants were recovered from infected ME-180 cells in decreased numbers, highlighting the importance of the αCA and βCA in intracellular survival and replication. Several other publications have reported αCA as an essential protein for the viability of &lt;i&gt;N. gonorrhoeae&lt;/i&gt;. Since our findings on αCA were not in agreement with those published reports, we constructed an additional mutant of αCA gene by deleting the entire ORF of this gene. This second ΔαCA mutant was similar to our first ΔαCA mutant and the parent strain in terms of growth in ambient CO&lt;sub&gt;2&lt;/sub&gt; concentrations. Thus, we conclude that αCA is dispensable for the viability of &lt;i&gt;N. gonorrhoeae&lt;/i&gt;. Unlike our ΔαCA or ΔβCA mutants, our ΔγCA mutant was not different from the parent in growth, metabolism, or intracellular survival. Overall, we conclude that αCA is dispensable for the viability, growth, and pH homeostasis but is important for metabolism and intracellular survival of &lt;i&gt;N. gonorrhoeae&lt;/i&gt;. The βCA is indispensable for the viability of &lt;i&gt;N. gonorrhoeae&lt;/i&gt;, a","PeriodicalId":73024,"journal":{"name":"FEMS microbes","volume":"7 ","pages":"xtag021"},"PeriodicalIF":4.2,"publicationDate":"2026-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13147457/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147846596","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}