Applied and Environmental Microbiology最新文献

{"title":"Immobilization of alginate C-5 epimerases using <i>Bacillus subtilis</i> spore display.","authors":"Jan Benedict Spannenkrebs, Agnes Beenfeldt Petersen, Finn Lillelund Aachmann, Johannes Kabisch","doi":"10.1128/aem.00298-25","DOIUrl":"https://doi.org/10.1128/aem.00298-25","url":null,"abstract":"<p><p>Alginates are the most abundant polysaccharides found in brown seaweed, composed of (1→4)-linked β-D-mannuronate (M) and its C-5 epimer, α-L-guluronate (G). The G-blocks of alginate possess viscosifying and gelling properties, making alginates valuable industrial polysaccharides. Alginate epimerases are enzymes epimerizing M to G, enhancing the usability and value of alginate. The three alginate epimerases AlgE1, AlgE4, and AlgE6 were immobilized using <i>Bacillus subtilis</i> spores displaying the epimerases fused to the spore crust protein CotY. To our knowledge, this is the first display of immobilized alginate-modifying enzymes. Activity assays of the four AlgE4-displaying spore strains showed that AlgE4 produced MG-blocks from polyM alginate. AlgE4 was tested linked by its N- and C-termini. Two linkers with different flexibility were tested, both containing a TEV protease cleavage site. Immobilizing alginate epimerases on <i>B. subtilis</i> spores resulted in a recyclable system that is easy to isolate and reuse, thus opening possibilities for industrial application. Recyclability was demonstrated by performing five consecutive reactions with the same batch of AlgE4 spores, with the spores retaining 24% of the starting activity after four rounds of reuse. TEV cleavage of spore-displayed enzyme was optimized using spores displaying a green fluorescent protein, and these optimized conditions were used to cleave AlgE4 off the spores. The cleavage of four AlgE4-displaying spores was successful, but cleavage efficiency varied depending on which terminus of AlgE4 was fused to CotY.</p><p><strong>Importance: </strong>Seaweed is a scalable resource that requires no fresh water, fertilizer, or arable land, making it an important biomass for bioeconomies. Alginates are a major component of brown seaweed and are widely used in food, feed, technical, and pharmacological industries. To tailor the functional properties of alginates, alginate epimerases have shown to be promising for postharvest valorization of alginate. This study investigates an efficient and easy method to produce immobilized alginate epimerases, thus opening new industrial use cases. In this study, the alginate epimerases are immobilized on the surface of <i>Bacillus subtilis</i> spores. The bacterium forms spores in reaction to nutrient starvation, which are highly resistant to external influences and can be repurposed as a stable protein display platform for numerous applications due to its ease of genomic manipulation and cultivation.</p>","PeriodicalId":8002,"journal":{"name":"Applied and Environmental Microbiology","volume":" ","pages":"e0029825"},"PeriodicalIF":3.9,"publicationDate":"2025-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143771097","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Polyyne production is regulated by the transcriptional regulators PgnC and GacA in <i>Pseudomonas protegens</i> Pf-5.","authors":"Chiseche Mwanza, Maria Purnamasari, Daniel Back, Cahya Prihatna, Benjamin Philmus, Khaled H Almabruk, Taifo Mahmud, Lumeng Ye, Melvin D Bolton, Xiaogang Wu, Joyce E Loper, Qing Yan","doi":"10.1128/aem.02388-24","DOIUrl":"https://doi.org/10.1128/aem.02388-24","url":null,"abstract":"<p><p>Polyynes produced by bacteria have promising applications in agriculture and medicine due to their potent antimicrobial activities. Polyyne biosynthetic genes have been identified in <i>Pseudomonas</i> and <i>Burkholderia</i>. However, the molecular mechanisms underlying the regulation of polyyne biosynthesis remain largely unknown. In this study, we used a soil bacterium <i>Pseudomonas protegens</i> Pf-5, which was recently reported to produce polyyne called protegenin, as a model to investigate the regulation of bacterial polyyne production. Our results show that Pf-5 controls polyyne production at both the pathway-specific level and a higher global level. Mutation of <i>pgnC</i>, a transcriptional regulatory gene located in the polyyne biosynthetic gene cluster, abolished polyyne production. Gene expression analysis revealed that PgnC directly activates the promoter of polyyne biosynthetic genes. The production of polyyne also requires a global regulator GacA. Mutation of <i>gacA</i> decreased the translation of PgnC, which is consistent with the result that <i>pgnC</i> leader mRNA bound directly to RsmE, an RNA-binding protein negatively regulated by GacA. These results suggest that GacA induces the expression of the PgnC regulator, which in turn activates polyyne biosynthesis. Additionally, the polyyne-producing strain of Pf-5, but not the polyyne-nonproducing strain, could inhibit a broad spectrum of bacteria including both Gram-negative and Gram-positive bacteria.IMPORTANCEAntimicrobial metabolites produced by bacteria are widely used in agriculture and medicine to control plant, animal, and human pathogens. Although bacteria-derived polyynes have been identified as potent antimicrobials for decades, the molecular mechanisms by which bacteria regulate polyyne biosynthesis remain understudied. In this study, we found that polyyne biosynthesis is directly activated by a pathway-specific regulator PgnC, which is induced by a global regulator GacA through the RNA-binding protein RsmE in <i>Pseudomonas protegens</i>. To our knowledge, this work is the first comprehensive study of the regulatory mechanisms of bacterial polyyne biosynthesis at both pathway-specific level and global level. The discovered molecular mechanisms can help us optimize polyyne production for agricultural or medical applications.</p>","PeriodicalId":8002,"journal":{"name":"Applied and Environmental Microbiology","volume":" ","pages":"e0238824"},"PeriodicalIF":3.9,"publicationDate":"2025-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143771099","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Fresh pork microbiota is temporally dynamic and compositionally diverse across meat, contact surfaces, and processing lines in a pork processing facility.","authors":"A E Asmus, T N Gaire, K M Heimer, K E Belk, R S Singer, T J Johnson, N R Noyes","doi":"10.1128/aem.00044-25","DOIUrl":"https://doi.org/10.1128/aem.00044-25","url":null,"abstract":"<p><p>The goal of this study was to analyze the microbial profiles of meat and contact surfaces from two different processing lines in a pork processing plant, using a 16S rRNA gene amplicon sequencing workflow specifically designed to investigate fresh meat and environmental samples throughout a commercial production schedule. Results indicated that the microbiota differed between the meat and contact surface, both across the two processing lines and within each individual processing line. Differences in the microbiota composition were also strongly associated with both the specific processing dates and the time of day during processing. Much of this variation was associated with distinct amplicon sequence variants unique to each processing date and each processing line throughout the day. The abundance of key taxa associated with food safety and spoilage was also temporally dynamic across a production shift and was different between the meat and contact surface. Overall, the results of this study indicate significant differences in the microbial profiles of the meat and contact surfaces between two processing lines within the same plant. These differences are likely influenced by daily variation in processing and sanitation procedures, as well as differences in the design of the processing lines, which appear to affect the microbiotas of both the meat and contact surfaces.IMPORTANCEThis study provides critical knowledge that can be used as a foundation for tailored processes to improve fresh pork safety and quality, potentially customized to individual processing lines, time points within a shift, and/or production days. Additionally, this study provides a list of potential biological markers associated with food safety and quality that could be used by processors to develop and validate intervention strategies specific to different processing lines.</p>","PeriodicalId":8002,"journal":{"name":"Applied and Environmental Microbiology","volume":" ","pages":"e0004425"},"PeriodicalIF":3.9,"publicationDate":"2025-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143771094","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A dynamic protein interactome drives energy conservation and electron flux in <i>Thermococcus kodakarensis</i>.","authors":"Sere A Williams, Danielle M Riley, Teagan P Rockwood, David A Crosby, Katherine D Call, Jared J LeCuyer, Thomas J Santangelo","doi":"10.1128/aem.00293-25","DOIUrl":"https://doi.org/10.1128/aem.00293-25","url":null,"abstract":"<p><p>Life is supported by energy gains fueled by catabolism of a wide range of substrates, each reliant on the selective partitioning of electrons through redox (<u>red</u>uction and <u>ox</u>idation) reactions. Electron flux through tunable and regulated protein interactions provides dynamic routes for energy conservation, but how electron flux is regulated <i>in vivo</i>, particularly for archaeal metabolisms that support rapid growth at the thermodynamic limits of life, is poorly understood. Identification of <i>bona fide in vivo</i> protein assemblies and how such assemblies dictate the totality of electron flux is critical to our understanding of the regulation imposed on metabolism, energy production, and energy conservation. Here, 25 key proteins in central metabolic redox pathways in the model, genetically accessible, hyperthermophilic archaeon <i>Thermococcus kodakarensis</i>, were purified to reveal an extensive, dynamic, and tightly interconnected network of protein interactions that responds to environmental cues (such as the availability of various reductive sinks) to direct electron flux to maximize energetic gains. Interactions connecting disparate functions suggest many catabolic and anabolic activities occur in spatial proximity <i>in vivo</i>, and while protein complexes have been historically defined under optimal conditions, many of these complexes appear to maintain alternative partnerships in changing conditions. The totality of the results obtained redefines our understanding of <i>in vivo</i> assemblies driving ancient metabolic strategies supporting the growth of modern Archaea.IMPORTANCEGiven the potential for rational genetic manipulations of biofuel- and biotech-promising archaea to yield transformative results for major markets, it is a priority to define how the metabolisms of such species are controlled, at least in part, by <i>in vivo</i> protein assemblies, and from such, define routes of energy flux that can be most efficiently altered toward biofuel or biotechnological gains. Proteinaceous electron carriers (PECs, such as ferredoxins) offer the potential for specific protein-protein interactions to coordinate selective reductive flow. Employing the model, genetically accessible, hyperthermophilic archaeon, <i>Thermococcus kodakarensis</i>, we establish the metabolic protein interactome of 25 key redox proteins, revealing that each redox active protein has a dynamic partnership profile, suggesting catabolic and anabolic activities may occur in concert and in temporal and spatial proximity <i>in vivo</i>. These results reveal critical importance in evaluating the newly identified partnerships and their role and utility in providing regulated redox flux in <i>T. kodakarensis</i>.</p>","PeriodicalId":8002,"journal":{"name":"Applied and Environmental Microbiology","volume":" ","pages":"e0029325"},"PeriodicalIF":3.9,"publicationDate":"2025-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143770952","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Antimicrobial peptides: from discovery to developmental applications.","authors":"Qi Zhang","doi":"10.1128/aem.02115-24","DOIUrl":"https://doi.org/10.1128/aem.02115-24","url":null,"abstract":"<p><p>Antimicrobial resistance (AMR) has emerged as a significant crisis in global health. Due to their advantageous properties, antimicrobial peptides (AMPs) have garnered considerable attention as a potential alternative therapy to address the AMR crisis. These peptides might disrupt cell membranes or cell walls to exhibit antimicrobial activity, or modulate the immune response to promote recovery from diseases. In recent years, significant progress has been made in the research of AMPs, alongside the emergence of new challenges. This review first systematically summarizes and critically discusses recent advancements in understanding the characteristics and current landscapes of AMPs, as well as their regulatory mechanisms of action and practical applications, particularly those reported or approved within the last 5 years. Additionally, the principles, paths for their identification, and future research trends in AMPs are also analyzed following a discussion of the advantages and disadvantages of AMPs in comparison to conventional antibiotics. Unlike significant prior literature in this field, this report has summarized the latest major discovery methods for AMPs and, more importantly, emphasized their practical applications by supporting various viewpoints using selected examples of AMPs' applications in real-life scenarios. Besides, some emerging hot topics of AMPs, including those derived from gut microbiota and their potential synergistic effects in combating AMR, were profiled. All of these indicate the originality of the report and provide valuable references for future AMP discoveries and applications.</p>","PeriodicalId":8002,"journal":{"name":"Applied and Environmental Microbiology","volume":" ","pages":"e0211524"},"PeriodicalIF":3.9,"publicationDate":"2025-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143770959","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Anaerobic degradation of polycyclic aromatic hydrocarbons.","authors":"Isabelle Heker, Nadia A Samak, Yachao Kong, Rainer U Meckenstock","doi":"10.1128/aem.02268-24","DOIUrl":"https://doi.org/10.1128/aem.02268-24","url":null,"abstract":"<p><p>Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous and toxic pollutants in the environment that are mostly introduced through anthropogenic activities. They are very stable with low bioavailability and, because aerobic degradation is mostly limited in aquifers and sediments, often persist in anoxic systems. In this review, we elucidate the recent advances in PAH degradation by anaerobic, mostly sulfate-reducing cultures. The best-studied compound is naphthalene, the smallest and simplest PAH, which often serves as a model compound for anaerobic PAH degradation. In recent years, three-ring PAHs have also shifted into focus, using phenanthrene as a representative compound. Anaerobic degradation of PAHs has to overcome several biochemical problems. First, non-substituted PAHs have to be activated by carboxylation, which is chemically challenging and proposed to involve a 1,3-cycloaddition with a UbiD-like carboxylase and a prenylated flavin cofactor. The second key reaction is to overcome the resonance energy of the ring system, which is performed by consecutive two-electron reduction steps involving novel type III aryl-CoA reductases belonging to the old-yellow enzyme family. In naphthalene degradation, a type I aryl-CoA reductase is also involved in reducing a benzene ring structure. The third key reaction is the ring cleavage, involving β-oxidation-like reactions in cleaving ring I of naphthalene. Ring II, however, is opened by a novel lyase reaction at a tertiary, hydroxylated carbon atom. These principles are explained using examples of anaerobic naphthalene and phenanthrene degradation to give an overview of recent advances, from the initial activation of the molecules to the complete degradation to CO₂.</p>","PeriodicalId":8002,"journal":{"name":"Applied and Environmental Microbiology","volume":" ","pages":"e0226824"},"PeriodicalIF":3.9,"publicationDate":"2025-04-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143762875","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Discovery of two novel cutinases from a gut yeast of plastic-eating mealworm for polyester depolymerization.","authors":"Tong Huang, Jingya Zhang, Xuena Dong, Yu Yang","doi":"10.1128/aem.02562-24","DOIUrl":"https://doi.org/10.1128/aem.02562-24","url":null,"abstract":"<p><p>Identification of novel plastic-degrading enzymes is crucial for developing enzymatic degradation and recycling strategies for plastic waste. Here, we report the discovery of two novel cutinases, SiCut1 and SiCut2, from a yeast strain <i>Sakaguchia</i> sp. BIT-D3 was isolated from the gut of plastic-eating mealworms. Their amino acid sequences share less than 25% identity with all previously described cutinases and reveal a conserved S-D-H catalytic triad with a unique GYSKG motif. Their recombinant proteins were successfully overexpressed in <i>Pichia pastoris</i>. The pH range for both enzymes was 4.0 to 11.0 and the temperature range for SiCut1 and SiCut2 was 10°C to 50°C and 10°C to 70°C, respectively. Both enzymes showed strong activity against apple cutin and short-chain fatty acid esters of <i>p</i>-nitrophenol and glycerol, substantiating their classification as true cutinases. SiCut1 and SiCut2 have been demonstrated to exhibit efficient degradation of polycaprolactone (PCL) film, polybutylene succinate (PBS) film, and polyester-polyurethane (PUR) foam. Molecular docking and molecular dynamics simulations were used to elucidate the underlying mechanisms of the observed catalytic activity and thermal stability. This study shows that SiCut1 and SiCut2 are novel yeast-derived cutinases with the potential for depolymerization and recycling of plastic waste.IMPORTANCEThe identification of novel plastic-degrading enzymes is critical in addressing the pervasive problem of plastic pollution. This study presents two unique cutinases, SiCut1 and SiCut2, derived from the yeast <i>Sakaguchia</i> sp. BIT-D3 isolated from the gut of plastic-feeding mealworms. Despite sharing less than 25% sequence identity with known cutinases, both enzymes exhibit remarkable degradation capabilities against various polyester plastics, including polycaprolactone (PCL) film, polybutylene succinate (PBS) film, and polyester-polyurethane (PUR) foam. Our results elucidate the catalytic mechanisms of SiCut1 and SiCut2 and provide insights into their potential applications in enzymatic degradation and recycling strategies. By harnessing the gut microbiota of plastic-degrading organisms, this research lays the foundation for innovative enzyme-based solutions to reduce plastic waste and promote sustainable practices in waste management.</p>","PeriodicalId":8002,"journal":{"name":"Applied and Environmental Microbiology","volume":" ","pages":"e0256224"},"PeriodicalIF":3.9,"publicationDate":"2025-04-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143762513","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A suite of ddPCR assays targeting microbial pathogens for improved management of shellfish aquaculture.","authors":"Mark Ciesielski, Thomas Clerkin, Nicholas Funnell, Tal Ben-Horin, Rachel T Noble","doi":"10.1128/aem.02149-24","DOIUrl":"https://doi.org/10.1128/aem.02149-24","url":null,"abstract":"<p><p>The shellfish aquaculture industry is one of the fastest-growing sectors of global food production, but it is currently facing major challenges stemming from microbial pathogens. This study presents an optimized and validated suite of droplet digital PCR (ddPCR) assays using water samples proximal to oyster farms in North Carolina to quantify pathogens relevant to the aquaculture industry. Two of the molecular assays enable the quantification of the pathogens, <i>Vibrio parahaemolyticus</i> and <i>Perkinsus marinus</i>, that threaten human health and oyster performance, respectively. This work also introduces two ddPCR assays that enable the simultaneous quantification of at least nine ecologically relevant <i>Vibrio spp</i>. using only two sets of primers and probes targeting the glycosyl hydrolase family 18 (GH18) domain of the <i>chiA</i> gene in <i>Vibrio</i> bacteria. The entire suite of assays was applied to single assessments at 12 sites, revealing heterogeneity in microbial pathogen concentrations across the coastal landscape and variability of abundances within individual estuarine river systems. Additionally, a longitudinal study conducted at a demonstration lease elucidated unique temporal trends for all microbial targets. Notably, when concentrations of <i>Vibrio spp</i>. quantified using the two assays targeting the <i>chiA</i> gene reached their maximum, the daily probability of mortality increased, suggesting a role for other ecologically pertinent <i>Vibrio spp</i>. in the progression of mortality that would otherwise be missed. This study highlights the utility of ddPCR for the advancement of shellfish management by offering insights into the spaciotemporal dynamics of microbial pathogens.</p><p><strong>Importance: </strong>Climate change is drastically altering the environment and changing the abundance and geographical distribution of marine pathogens. These microbial species put additional pressure on the aquaculture industry by acting as sources of disease for animals important to the food industry as well as for humans upon consumption of contaminated food. To address growing concerns, high-resolution monitoring of pathogens can offer insights for effective management in a critical industry. Validated in the field, the suite of molecular droplet digital PCR assays presented here improves upon current methods, enabling the simultaneous quantification of several targets. This technology makes it possible to track pathogens as they move through the environment and reveals changes in abundance that may inform adjustments to farming practices aimed at mitigating negative outcomes. Additionally, this work presents a unique approach to molecular assay design that unveils potential drivers of ecological shifts and emerging etiologies of disease more efficiently.</p>","PeriodicalId":8002,"journal":{"name":"Applied and Environmental Microbiology","volume":" ","pages":"e0214924"},"PeriodicalIF":3.9,"publicationDate":"2025-04-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143762869","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"<i>Clostridioides difficile</i> in feral horse populations in Australia.","authors":"Natasza M R Hain-Saunders, Daniel R Knight, Andrea Harvey, Mieghan Bruce, Brian A Hampson, Thomas V Riley","doi":"10.1128/aem.02114-24","DOIUrl":"https://doi.org/10.1128/aem.02114-24","url":null,"abstract":"<p><p><i>Clostridioides difficile</i> is a known cause of diarrhea and colitis in human and non-human animals. While <i>C. difficile</i> is regularly isolated from domesticated horses, little is known about its prevalence in wild or feral populations. In Australia, the horse population encompasses a mix of both domesticated and feral animals, with the feral population of 400,000 estimated to be the largest in the world. This study investigated the presence and characteristics of <i>C. difficile</i> in Australian feral horses and evaluated their potential as a source or reservoir of <i>C. difficile</i> in the wider community. Fecal samples (<i>n</i> = 380) were collected from free-roaming feral horses from five Australian jurisdictions and cultured for <i>C. difficile</i>. Isolates were characterized by PCR ribotyping and toxin profiling. Antimicrobial susceptibility testing was performed for fidaxomicin, vancomycin, metronidazole, rifaximin, clindamycin, erythromycin, amoxicillin-clavulanate, moxifloxacin, meropenem, and tetracycline. <i>C. difficile</i> was isolated from 45 of the 380 samples (11.8%)-one-third of that seen in recent studies on Australian domesticated horses but consistent with wild animal species worldwide. Forty ribotypes (RTs) were identified, 28 of which (70%) were novel; other RTs had been previously reported in humans, livestock, and soils. Eighteen toxigenic <i>C. difficile</i> strains were isolated, of which eight contain binary toxin genes. Strains were largely susceptible to the antimicrobial agents tested. This investigation provides preliminary information on <i>C. difficile</i> in feral horses in Australia and allows a comparison with their domestic counterparts. The findings support the hypothesis that all horse feces represent a potential source of <i>C. difficile</i> in the community.</p><p><strong>Importance: </strong><i>Clostridioides difficile</i> poses an ongoing threat to healthcare in the community, with increasing evidence of transmission outside the hospital setting. In keeping with a One Health model of dispersion, investigations into this microorganism within the wider environment are vital to understanding this evolving epidemiology. Australia has the biggest population of feral horses in the world, and this study of <i>C. difficile</i> in feral horses provides insight into the role of non-domesticated animals in the dissemination of <i>C. difficile</i>. Examination of prevalence and characterization of isolates provides a baseline for evaluating the effect of antimicrobials and other factors associated with domestication on equine <i>C. difficile</i> infection.</p>","PeriodicalId":8002,"journal":{"name":"Applied and Environmental Microbiology","volume":" ","pages":"e0211424"},"PeriodicalIF":3.9,"publicationDate":"2025-04-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143762852","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Novel and diverse features identified in the genomes of bacteria isolated from a hydrothermal vent plume.","authors":"S R Major, J M Polinski, K Penn, M Rodrigue, M J Harke","doi":"10.1128/aem.02593-24","DOIUrl":"https://doi.org/10.1128/aem.02593-24","url":null,"abstract":"<p><p>Hydrothermal vent plumes (HVPs), formed by high-temperature vent emissions, are rich in compounds that support chemosynthesis and serve as reservoirs of microbial diversity and genetic innovation. Through turbulence, mixing, and interaction with subsea currents, vent communities are thought to disperse across ocean basins. In this study, we focused on the plume of the Moytirra hydrothermal vent field, a relatively unexplored site, to investigate its microbial inhabitants. We cultured bacteria from the Moytirra HVP using 11 different media types and performed complete genome sequencing on 12 isolates. Our analyses revealed four putatively novel species from the <i>Thalassobaculum</i>, <i>Sulfitobacter</i>, <i>Idiomarina</i>, and <i>Christiangramia</i> genera. Comparative genomics identified unique genomic islands containing biosynthetic gene clusters, including a novel Non-Ribosomal Peptide Synthetase/Polyketide Synthase cluster, toxin-antitoxin systems, and evidence of horizontal gene transfer facilitated by prophages. These findings underscore the potential of HVPs as a source of novel microbial species and biotechnologically relevant genes, contributing to our understanding of the biodiversity and genetic complexity of these extreme environments.IMPORTANCEHydrothermal vents are dynamic environments that offer unique nutrients for chemosynthetic organisms to drive biology in the deep-sea. The dynamics of these ecosystems are thought to drive genomic innovation in resident populations. Hydrothermal vent plumes (HVPs) mix with surrounding water, carrying local microbiota with them and dispersing for hundreds of kilometers. This study isolated bacteria from a HVP to capture a genomic snapshot of the microbial community, revealing four putatively novel species of bacteria within three taxonomic classes. The addition of these genomes to public databases provides valuable insights into the genomic function, architecture, and novel biosynthetic gene clusters of bacteria found in these extreme environments.</p>","PeriodicalId":8002,"journal":{"name":"Applied and Environmental Microbiology","volume":" ","pages":"e0259324"},"PeriodicalIF":3.9,"publicationDate":"2025-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143750791","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}