Microbiology-Sgm最新文献

{"title":"The influence of the polyamine synthesis pathways on <i>Pseudomonas syringae</i> virulence and plant interaction.","authors":"Leandro Solmi, Franco Rubén Rossi, Fernando Matías Romero, Marcel Bach-Pages, Gail M Preston, Andrés Gárriz","doi":"10.1099/mic.0.001569","DOIUrl":"10.1099/mic.0.001569","url":null,"abstract":"<p><p>This study investigates the role of polyamine biosynthesis in the pathogenesis of the bacterial phytopathogen <i>Pseudomonas syringae</i> pv. <i>tomato</i>. Through a comprehensive phenotypic analysis of mutant strains affected in the synthesis of putrescine and spermidine, we reveal a complex interplay between this metabolic pathway and bacterial virulence. Disruption of putrescine synthesis impairs a variety of virulence traits such as motility, biofilm formation, siderophore production, prevention of plant stomatal closure and the functionality of the type III secretion system. This is reversed by reintroducing the deleted genes, but not by the supplementation of culture media with putrescine or apoplastic washing fluids (AWF). Similarly, suppression of spermidine biosynthesis results in a comparable phenotype. However, in this case, the wild-type phenotype is restored by adding spermidine, AWF or expressing the spermidine synthase gene. We conclude that both putrescine and spermidine are important for bacterial virulence and that plant-derived spermidine can partially compensate for bacterial needs. Accordingly, whereas putrescine deficiency leads to a hypovirulent phenotype, spermidine synthesis perturbation does not affect plant colonization. These findings emphasize the critical role of polyamine metabolism in the plant invasion process by bacterial pathogens.</p>","PeriodicalId":49819,"journal":{"name":"Microbiology-Sgm","volume":"171 6","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12152252/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144259228","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Acquired CRISPR spacers and rhamnose-glucose polysaccharide defects confer resistance to <i>Streptococcus mutans</i> phage ɸAPCM01.","authors":"Lucas A Wall, Daniel Wall","doi":"10.1099/mic.0.001575","DOIUrl":"10.1099/mic.0.001575","url":null,"abstract":"<p><p><i>Streptococcus mutans</i> is commonly associated with the development of dental caries worldwide. Due to their specificity for <i>S. mutans</i>, phage represents a promising avenue for future targeted therapeutic strategies. In this study, we investigated how phage resistance develops in <i>S. mutans</i>. As a model phage, we used ɸAPCM01, which is known to infect a serotype e strain. We isolated and sequenced the genomes of 15 spontaneous resistant mutants and found that 10 had acquired novel clustered regularly interspaced short palindromic repeats (CRIPSR) spacers targeting the phage, with a total of 18 new spacers identified. Additionally, eight strains contained mutations in rhamnose-glucose polysaccharide biosynthetic genes, three of which also acquired spacers. Only the <i>rgp</i> mutants exhibited defects in phage adsorption, supporting the role of these cell surface glycans as the phage receptor. Mutations in <i>rgpF</i> and the newly identified gene <i>rgpX</i> led to severe cell division defects and impaired biofilm formation, the latter of which was also shared by an <i>rgpD</i> mutant. Thus, <i>rgp</i> mutations confer phage resistance but impose severe fitness costs, limiting pathogenic potential. Surprisingly, we found that ɸAPCM01 was capable of binding to and injecting its genome into UA159, a model serotype c strain. However, UA159 was resistant to infection due to an unknown post-entry defence mechanism. Consequently, ɸAPCM01 has the potential to infect both major serotypes associated with dental caries.</p>","PeriodicalId":49819,"journal":{"name":"Microbiology-Sgm","volume":"171 6","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12178566/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144334322","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Culturomics from field-grown crop plants using dilution to extinction, two-step library preparation and amplicon sequencing.","authors":"Eglantina Lopez-Echartea, Nicholas Dusek, Mallory Misialek, Mohammad Al Mahmud-Un-Nabi, Riley Williamson, Komal Marathe, Barney A Geddes","doi":"10.1099/mic.0.001571","DOIUrl":"10.1099/mic.0.001571","url":null,"abstract":"<p><p>Culturomics approaches have advanced microbial research by enabling the high-throughput isolation and characterization of a broader range of bacterial taxa, including some previously considered unculturable. Here, we present the testing and optimization of a protocol for isolating and identifying hundreds of cultivable microbes from field-grown plants. This protocol was tested and optimized using the root microbiomes of field-grown corn and pea plants under varying environmental conditions in ND, USA. By employing dilution-to-extinction culturing and a two-step barcoding PCR strategy targeting the V4 region of the 16S rRNA gene, we identified over 200 unique bacterial isolates. The optimized bioinformatic pipeline, built around the DADA2 package, ensured accurate amplicon sequence variant detection and taxonomy assignment. The resulting bacterial isolates span diverse phylogenetic groups, including plant-associated taxa known for promoting plant growth and mitigating stress. Our findings highlight the value of culturomics in generating microbial collections for synthetic community design and advancing plant-microbe interaction research. The protocol's scalability, cost-effectiveness and robust performance demonstrate its potential for widespread application in agricultural microbiome studies.</p>","PeriodicalId":49819,"journal":{"name":"Microbiology-Sgm","volume":"171 6","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12174589/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144318527","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Perturbation of the MetJ regulon impacts the consequences of 2-aminoacrylate stress in <i>Salmonella enterica</i>.","authors":"Bryce R Sawyer, Wangchen Shen, Diana M Downs","doi":"10.1099/mic.0.001572","DOIUrl":"10.1099/mic.0.001572","url":null,"abstract":"<p><p>In the absence of the broadly conserved deaminase RidA (Reactive intermediate deaminase A), <i>Salmonella enterica</i> and other organisms accumulate the reactive enamine species 2-aminoacrylate (2AA). Free 2AA, generated from serine by the serine/threonine dehydratase IlvA, reacts with and covalently inactivates a subset of pyridoxal 5'-phosphate-dependent enzymes. The metabolic stress caused by 2AA generates growth defects in <i>S. enterica</i>, including (i) when l-alanine is used as a nitrogen source, (ii) when pyruvate is used as a carbon source or (iii) in the presence of exogenous serine. Although the enzymatic targets of 2AA are consistent between growth conditions, the consequences of 2AA-dependent damage differ depending on the distribution of metabolic flux required in different conditions. Analysing the suppressors of a <i>ridA</i> mutant has furthered our understanding of the RidA stress paradigm and, more generally, how a metabolic network responds to perturbation. Many such suppressors modulate the metabolic network to eliminate 2AA production by IlvA. Here, we describe that eliminating the MetJ transcriptional repressor allows a <i>ridA</i> mutant to grow in the presence of 2AA stress in each of the three conditions. The mechanisms by which a Δ<i>metJ</i> suppresses a <i>ridA</i> mutant are nuanced and medium-dependent, emphasizing that consequences of 2AA stress differ based on environmental and metabolic context.</p>","PeriodicalId":49819,"journal":{"name":"Microbiology-Sgm","volume":"171 6","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144477581","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Pharmaco-psychiatry and gut microbiome: a systematic review of effects of psychotropic drugs for bipolar disorder.","authors":"Truong An Bui, Benjamin R O'Croinin, Liz Dennett, Ian R Winship, Andrew J Greenshaw","doi":"10.1099/mic.0.001568","DOIUrl":"https://doi.org/10.1099/mic.0.001568","url":null,"abstract":"&lt;p&gt;&lt;p&gt;Despite being one of the most common and debilitating mood disorders, bipolar disorder is often misdiagnosed and undertreated. Its pathogenesis is complex, with significant patient variability and inconsistent treatment effectiveness. The brain-gut-microbiota axis plays a critical role in bipolar disorder by modulating neurotransmitter secretion, gut peptides and systemic inflammation. However, the mechanisms by which psychotropic treatments influence gut microbiota composition and their implications for clinical outcomes remain poorly understood. This systematic review evaluated the impact of psychotropic drugs on gut microbiota and their potential role in bipolar disorder treatment outcomes. A comprehensive search across Ovid MEDLINE, Embase, APA PsycINFO, Scopus and PubMed yielded 314 articles, of which 12 met the inclusion criteria (last search: 13 August 2024). The studies included were those on adults with bipolar disorder type I or II receiving psychopharmacological treatments; those with group comparisons (e.g. healthy controls vs. medicated vs. non-medicated) investigating gut microbiome changes; and no restrictions applied to psychotic features, comorbid anxiety or prior treatment responses. Exclusions involved individual case reports, incomplete conference submissions or early terminated studies lacking efficacy analysis. Cochrane ROBINS-I V2 tool was used to measure the risk of bias, and the GRADE approach was utilized to rate the certainty of evidence in included studies. Two authors independently extracted data into Excel spreadsheets, categorizing demographic and clinical characteristics, describing microbiome analytic methods and summarizing findings on gut microbiome changes post-treatment. Given the high variability in methods and outcome measures across studies, all details were reported without data conversion. Data synthesis reveals that psychotropic treatments, including quetiapine and lithium, influence gut microbiota by increasing the abundance of beneficial bacteria supporting gut health and pathogenic bacteria linked to metabolic dysfunction. Notably, female patients exhibited more significant changes in microbial diversity following psychotropic treatment. Additionally, patients treated with psychotropics showed an increased prevalence of gut bacteria associated with multidrug antibiotic resistance. In bipolar patients treated with quetiapine, responders - those experiencing improved depressive symptom scores - displayed distinct gut microbiome profiles more closely resembling those of healthy individuals compared with non-responders. Responders also exhibited neural connectivity patterns similar to healthy subjects. These findings underscore the complex dual impact of psychotropic medications on gut microbiota, with potential consequences for both gut and mental health. While the enrichment of beneficial bacteria may support gut health, the rise in antibiotic-resistant and metabolically disruptive bacteria is con","PeriodicalId":49819,"journal":{"name":"Microbiology-Sgm","volume":"171 6","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144318528","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"History shapes regulatory and evolutionary responses to tigecycline in two reference strains of <i>Acinetobacter baumannii</i>.","authors":"Alecia B Rokes, Alfonso Santos-Lopez, Vaughn S Cooper","doi":"10.1099/mic.0.001570","DOIUrl":"10.1099/mic.0.001570","url":null,"abstract":"<p><p>Evolutionary history encompasses both genetic and phenotypic bacterial differences; however, the extent to which this history influences drug response and antimicrobial resistance (AMR) adaptation remains unclear. Historical contingencies arise when elements from an organism's past leave lasting effects on the genome, altering the paths available for adaptation. Here, we compare two diverging reference strains of <i>Acinetobacter baumannii</i>, representative of archaic and contemporary infections, to study the impact of deep historical differences shaped by decades of adaptation in varying antibiotic and host pressures. We evaluated these effects by comparing immediate and adaptive responses to the last-resort antibiotic, tigecycline (TGC). The strains demonstrated divergent transcriptional responses, suggesting that baseline transcript levels may dictate global responses to antibiotics. Experimental evolution in TGC revealed clear differences in population dynamics, with hard sweeps in populations founded by one strain and no mutations reaching fixation in the other strain. AMR was acquired through predictable mechanisms of increased efflux and drug target modification; however, efflux targets were dictated by strain background. Genetic adaptation may outweigh historic differences in transcriptional networks, as evolved populations no longer show transcriptomic signatures of drug response. Importantly, fitness-resistance trade-offs were only observed in lineages evolved from the archaic strain, while the contemporary reference isolate suffered no fitness defects. This suggests that decades of adaptation to antibiotics resulted in pre-existing compensatory mechanisms in the more contemporary isolate, an important example of a beneficial effect of historical contingencies.</p>","PeriodicalId":49819,"journal":{"name":"Microbiology-Sgm","volume":"171 6","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12149411/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144250565","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Role of a FAD-dependent monooxygenase in diazo group functionalization of kinamycin in <i>Streptomyces ambofaciens</i>.","authors":"Cláudia M Vicente, Alexis Boutilliat, Laurence Hôtel, Cédric Paris, Bertrand Aigle","doi":"10.1099/mic.0.001576","DOIUrl":"10.1099/mic.0.001576","url":null,"abstract":"<p><p>Kinamycin biosynthesis is a complex process that has been extensively studied over the years, yet specific enzymatic steps continue to be unveiled. A diazo group present in the molecule is responsible for the promising antitumour activity of kinamycins, but its installation in the specific strain <i>Streptomyces ambofaciens</i> has yet to be characterized. In this study, we explore the diazo functionalization of kinamycin in this strain. A FAD-dependent monooxygenase is identified, which is essential for kinamycin biosynthesis. In its absence, stealthin C accumulates instead, likely as a pathway shunt product. Furthermore, as a result of the position of the gene encoding this monooxygenase, named <i>alp2F</i>, we also propose new boundaries of the kinamycin biosynthetic gene cluster, resulting in a large cluster spanning over 72 kb. This work paves the way for the continued understanding of the biosynthetic steps that are characteristic of diazo-containing natural products and provides new biocatalysts for molecular engineering and accelerates bioactive compounds production.</p>","PeriodicalId":49819,"journal":{"name":"Microbiology-Sgm","volume":"171 6","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12181624/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144334325","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Functional properties of <i>Candida albicans</i> extracellular vesicles released in the presence of the antifungal drugs amphotericin B, fluconazole and caspofungin.","authors":"Kamila Kulig, Elzbieta Rudolphi-Szydlo, Anna Barbasz, Magdalena Surowiec, Ewelina Wronowska, Katarzyna Kowalik, Dorota Satala, Grazyna Bras, Olga Barczyk-Woznicka, Elzbieta Karnas, Elzbieta Pyza, Ewa Zuba-Surma, Maria Rapala-Kozik, Justyna Karkowska-Kuleta","doi":"10.1099/mic.0.001565","DOIUrl":"https://doi.org/10.1099/mic.0.001565","url":null,"abstract":"<p><p>The prevalence of diseases caused by pathogenic fungi of the <i>Candida</i> genus is currently a significant problem, particularly due to the emerging antifungal drug resistance and increasing number of immunocompromised individuals susceptible to opportunistic infections. Recently, it has been shown that fungal extracellular vesicles (EVs) - nanometre-sized structures of cellular origin, equipped with varied cargo enclosed by lipid bilayer - may play a vital role in the response of pathogen cells to antifungal treatment. In this work, we demonstrated that <i>Candida albicans</i> yeast cells grown at the subinhibitory concentrations of three commonly used antifungal drugs - amphotericin B, fluconazole and caspofungin - released a greater number of EVs than fungal cells grown under drug-free conditions. Moreover, these EVs exhibited some variability in size and protein composition, yet they consistently induced the production of the pro-inflammatory cytokine IL-8 by THP-1 macrophage-like cells at levels comparable to control EVs. In studies using the invertebrate model organism <i>Galleria mellonella</i>, EVs released by cells exposed to antifungals did not cause a significant increase in larval mortality, similar to control EVs, although they triggered a remarkably lower activation of phenol oxidase in larval haemolymph. In addition, EVs produced in the presence of caspofungin interacted more noticeably with the membrane of U-937 pro-monocytic cells as indicated by measurements of zeta potential changes. Furthermore, tested EVs contributed to increased tolerance of <i>C. albicans</i> cells to the antifungal drugs. These observations underscore the unmissable role of EVs in the response of pathogen cells to antifungal treatment and highlight the importance of understanding EV functionalities in antifungal resistance.</p>","PeriodicalId":49819,"journal":{"name":"Microbiology-Sgm","volume":"171 6","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144276464","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"An invasive phenotype induced by relaxation of DNA supercoiling in <i>Campylobacter jejuni</i> triggers disruption of tight junctions of intestinal spheroids.","authors":"Matthew V X Whelan, Laura Ardill, Jeremy C Simpson, Tadhg Ó Cróinín","doi":"10.1099/mic.0.001560","DOIUrl":"10.1099/mic.0.001560","url":null,"abstract":"<p><p>The relaxation of DNA supercoiling in <i>Campylobacter jejuni</i> leads to increased protein secretion and a more invasive phenotype, but little is known about the specific mechanisms involved. The aim of this study was to elucidate how these induced bacteria interact with epithelial cells to mediate invasion using different cell models. In HT29 epithelial cell monolayers, pre-treatment of <i>C. jejuni</i> with novobiocin to relax DNA supercoiling significantly increased bacterial association and invasion, forming clusters at cell junctions. This invasive phenotype, which we term <i>C. jejuni</i> supercoiling induced (SI), led to marked disruption of tight junctions (TJs) and adherens junctions, as evidenced by the loss of occludin and <i>β</i>-catenin signal during infection. In a 3D spheroid model, <i>C. jejuni</i> (SI) displayed increased association with and penetration into the centre of spheroids, although significant disruption of their integrity was not observed. Further investigation revealed that cytoskeletal dynamics play a pivotal role in this process; inhibition of microtubule polymerization, but not actin polymerization, rescued the <i>β</i>-catenin disruption induced by <i>C. jejuni</i> (SI), highlighting microtubules as key targets for <i>C. jejuni</i> virulence. This study reveals that SI invasion by <i>C. jejuni</i> is associated with the disruption of TJs, suggesting a paracellular route of invasion.</p>","PeriodicalId":49819,"journal":{"name":"Microbiology-Sgm","volume":"171 6","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12141748/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144227330","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Microbial Primer: Challenges and opportunities in the treatment of chronic polymicrobial infections ‒ an eco-evolutionary perspective.","authors":"Jennifer M Farrell, Sam P Brown","doi":"10.1099/mic.0.001567","DOIUrl":"10.1099/mic.0.001567","url":null,"abstract":"<p><p>In this primer, we will review the key distinctions between acute and chronic infections, between mono- and polymicrobial infections and how these distinctions work together to generate the growing crisis of chronic polymicrobial infections. Chronic (non-resolving) infections place a large and growing burden on human health, globally. Following an introduction to the basic properties of chronic polymicrobial infections, we will use an ecological and evolutionary perspective to help outline a research agenda for this field, flagging both challenges and opportunities for improved infection prevention, diagnosis and treatment.</p>","PeriodicalId":49819,"journal":{"name":"Microbiology-Sgm","volume":"171 6","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12181621/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144334324","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}