Applied and Environmental Microbiology最新文献

{"title":"Nationwide surveillance of carbapenem-resistant Gram-negative pathogens in the Lebanese environment.","authors":"Zahraa F Samadi, Zeinab R Hodroj, Ziad C Jabbour, Hadi M Hussein, Abdallah Kurdi, Dayana Shoukair, Ricardo F Bitar, Hadi H Chebaro, Jean Marie J Al Semaani, Mohamad T Al Hajjar, Housein H Zeaiter, Lama Hamadeh, Rami Mahfouz, Lama H Noueihed, Jad H Hachem, Mahmoud I Khalil, Rana El Hajj, Ghassan M Matar, Antoine G Abou Fayad","doi":"10.1128/aem.01932-24","DOIUrl":"https://doi.org/10.1128/aem.01932-24","url":null,"abstract":"<p><p>Gram-negative ESKAPE pathogens with carbapenem resistance pose a significant health threat. Despite extensive research on the spread of these pathogens within Lebanese hospital settings, their emergence in environmental settings remains understudied. This study aimed to explore the environmental spread of carbapenem resistance among Gram-negative bacteria isolated from environmental samples in nine districts across Lebanon. A total of 250 samples were collected from wild animals, sewage, water, and soil between June 2022 and September 2023. Samples were streaked on MacConkey agar plates supplemented with 2 mg/L meropenem. Bacterial species were identified primarily using API20E. Antimicrobial susceptibility profiles were determined by the disk diffusion method and the Vitek 2 compact system. Meropenem-resistant Gram-negative bacteria were further characterized by whole-genome sequencing, and each of the bacterial species, sequence types, resistance genes, and plasmids was detected by sequence data analysis. We successfully isolated 130 carbapenem-resistant isolates from various samples, 67 of which belonged to the ESKAPE pathogens list and showed a multidrug-resistant (MDR) profile. The distribution of the latter was as follows: <i>Escherichia coli</i> (65.67%), <i>Acinetobacter baumannii</i> (16.42%), <i>Pseudomonas aeruginosa</i> (11.94%), and <i>Klebsiella pneumoniae</i> (5.97%). Several carbapenem resistance genes were detected, with a prevalence of <i>bla</i>NDM-5 in <i>Escherichia coli</i> and <i>Klebsiella pneumoniae</i>, <i>bla</i>IMP-1 and mexAB-OprM efflux pumps in <i>Pseudomonas aeruginosa</i>, and <i>bla</i>OXA-23 in <i>Acinetobacter baumannii</i>. Our findings revealed a widespread distribution of carbapenem-resistant ESKAPE bacteria in Lebanon, underscoring the significant public health risk posed by these pathogens. This highlights the urgent need to address the dissemination of antibiotic resistance in Lebanese environmental settings.</p><p><strong>Importance: </strong>The emergence of antimicrobial resistance (AMR) extremely burdens public health and increases morbid and mortal threats in Lebanon. While the majority of the studies in our country target antimicrobial resistance in clinical settings, fewer studies focus on antimicrobial resistance dissemination in the environment. The significance of our research is that it sheds light on the environment as a less explored yet equally crucial sector in the spread of AMR. Here, we isolated carbapenemase-producing bacteria (<i>Escherichia coli</i>, <i>Klebsiella pneumoniae</i>, <i>Pseudomonas aeruginosa</i>, and <i>Acinetobacter baumannii</i>) that were categorized as multidrug resistant (MDR) from diverse environmental sources in multiple provinces across Lebanon. The finding of carbapenem-resistant bacteria carrying plasmids represents a potential risk due to the possible spread of resistance genes via horizontal gene transfer across the environment and hospital settings. Thi","PeriodicalId":8002,"journal":{"name":"Applied and Environmental Microbiology","volume":" ","pages":"e0193224"},"PeriodicalIF":3.9,"publicationDate":"2025-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144257144","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":"Sporulation at reduced water activity impairs germination kinetics of <i>Bacillus subtilis</i> spores.","authors":"Víctor Freire, Santiago Condón, Elisa Gayán","doi":"10.1128/aem.00677-25","DOIUrl":"https://doi.org/10.1128/aem.00677-25","url":null,"abstract":"<p><p>While the effect of sporulation temperature on spore germination has been extensively studied, the effect of other relevant environmental factors such as water activity (<i>a_w</i>) has been overlooked, despite the fact that sporulation niches with lower humidity than ideal culture media, such as soil, are common in nature. In this work, we characterized the germination kinetics of <i>B. subtilis</i> 168 spores produced at reduced <i>a_w</i> (0.98) using either glycerol (S_gly spores) or NaCl (S_salt spores) in comparison to spores prepared under optimal conditions (S_control spores, <i>a_w</i> ~0.99) in a variety of nutrient and chemical stimuli, along with the effect of thermal activation. Spores produced at reduced <i>a_w</i> showed impaired germination to varying degrees depending on the nutrient and solute used to depress <i>a_w</i>. While S_gly spores exhibited germination defects in all the nutrients tested (a rich growth medium, L-alanine, L-valine, and the AGFK mixture) compared to S_control spores, S_salt populations showed an impaired response to L-alanine and L-valine. These nutrient germination defects of the S_gly and S_salt spores could not be reversed by heat activation. In addition, both populations displayed impaired germination in Ca-DPA, but increased germination rate in dodecylamine. The phenotypes of spores produced at reduced <i>a_w</i> suggested plausible alterations in their coat properties. Using mutant spores with coat morphogenesis defects and a 4 kDa FITC-dextran probe permeability test, we could infer that the impaired germination of S_salt spores in nutrients and Ca-DPA may involve alterations in the crust and/or outer coat, leading to reduced permeability.IMPORTANCEBacterial spores are causative agents of relevant zoonoses and foodborne diseases and are involved in food spoilage. Natural sporulation niches, such as soil, are exposed to a variety of changing environmental conditions, such as temperature and water activity (<i>a_w</i>), which strongly influence the dynamics of spore germination. This work provides the first data on the effect of lowering the <i>a_w</i> of the sporulation medium on spore germination kinetics, which, together with previous data on the effect of other environmental sporulation conditions and inter- and intraspecific variability, will help accurately predict germination and thus prevent the negative impacts of pathogenic and food spoiling spores. Furthermore, we inferred that alterations related to the coat are associated with impaired nutrient germination of spores produced at reduced <i>a_w</i> with the addition of NaCl. These findings may help develop novel and efficient strategies to control germination or eradicate spores.</p>","PeriodicalId":8002,"journal":{"name":"Applied and Environmental Microbiology","volume":" ","pages":"e0067725"},"PeriodicalIF":3.9,"publicationDate":"2025-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144257146","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":"Beyond antimicrobial resistance: MATE-type efflux pump FepA contributes to flagellum formation and virulence in <i>Listeria monocytogenes</i>.","authors":"Jing Xia, Guo Jiang, Yaru Luo, Zhe Wang, Jingjing Li, Zhanhong Fu, Qian Qin, Jiali Xu, Simin Deng, Mianmian Chen, Yue Han, Lingli Jiang, Houhui Song, Changyong Cheng","doi":"10.1128/aem.00462-25","DOIUrl":"https://doi.org/10.1128/aem.00462-25","url":null,"abstract":"<p><p><i>Listeria monocytogenes</i> is commonly found in nature and can readily contaminate various food products. Efflux pump proteins represent an essential group of proteins in bacteria, playing key roles in numerous biological processes. This study investigates the contribution of FepA to motility and virulence apart from antimicrobial resistance in <i>L. monocytogenes</i>. The minimum inhibitory concentrations of various antimicrobials and the survival of <i>L. monocytogenes</i> in medium containing these agents were assessed. Loss of FepA increased sensitivity to a range of antimicrobial agents and significantly impaired growth under antimicrobial pressure. We examined bacterial flagellum formation, flagellar gene transcription, and protein expression. Results indicated a marked decrease in flagellum formation in Δ<i>fepA</i> mutants, owing to reduced expression of key flagellar proteins such as FlhF and FlgG. In addition, results from cell infection, virulence genes transcription, and protein expression experiments revealed that FepA deletion diminished bacterial invasiveness and intracellular proliferation, correlating with decreased secretion of virulence proteins, including InlB, InlC, Mpl, PlcA, and LLO. These findings indicate that FepA is integral not only to antimicrobial resistance and <i>in vitro</i> adaptability but also to flagellar formation and virulence. This research helps deepen the understanding of mechanisms underlying drug resistance and pathogenicity in the significant foodborne pathogen <i>L. monocytogenes</i>.</p><p><strong>Importance: </strong><i>Listeria monocytogenes</i> is a significant zoonotic foodborne intracellular pathogen with a mortality rate of up to 20%-30%. This bacterium employs various mechanisms, including efflux pumps, to enhance its environmental adaptability and maintain infectivity. In this study, we discovered that the MATE-type multidrug efflux pump protein FepA is not only associated with bacterial resistance to multiple antimicrobials but also plays a crucial role in promoting flagellum formation, which is essential for motility and resistance to adverse environmental conditions. Additionally, FepA is involved in the secretion of virulence proteins, facilitating bacterial invasion and proliferation within the host. Our findings reveal, for the first time, that the multidrug efflux pump FepA contributes to flagellar formation and virulence, providing new insights into the mechanisms of environmental adaptation and virulence expression in <i>L. monocytogenes</i> and aiding in the discovery of potential therapeutic targets.</p>","PeriodicalId":8002,"journal":{"name":"Applied and Environmental Microbiology","volume":" ","pages":"e0046225"},"PeriodicalIF":3.9,"publicationDate":"2025-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144257212","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":"Ecophysiological behavior of major <i>Fusarium</i> species in response to combinations of temperature and water activity constraints.","authors":"Marie-Anne Garcia, Rémi Mahmoud, Marie-Odile Bancal, Pierre Bancal, Stéphane Bernillon, Laetitia Pinson-Gadais, Florence Richard-Forget, Marie Foulongne-Oriol","doi":"10.1128/aem.01832-24","DOIUrl":"https://doi.org/10.1128/aem.01832-24","url":null,"abstract":"<p><p><i>Fusarium</i> head blight (FHB) is a devastating fungal disease affecting cereals, caused by <i>Fusarium</i> species that can produce harmful mycotoxins. <i>Fusarium</i> species coexist within the same ecological niche during infection, with their population dynamics and associated mycotoxin patterns strongly influenced by the environment. This study provides a comprehensive investigation of the ecophysiological responses of the major <i>Fusarium</i> species causing FHB under varying abiotic factors. We assessed growth and mycotoxin production of different isolates of <i>Fusarium avenaceum, Fusarium graminearum</i>, <i>Fusarium langsethiae, Fusarium poae,</i> and <i>Fusarium tricinctum</i> under 24 combinations of temperature (θ = 15, 20, 25, 30°C) and water activity levels (<i>a</i>_<i>w</i> = 0.99, 0.98, 0.97, 0.96, 0.95, 0.94). Our findings indicated that θ, <i>a</i>_<i>w</i>, and their interaction have a main significant impact on species behavior. Thanks to innovative statistical approaches using fungal growth data from optical density measurements and mycotoxin quantification, we demonstrated significant inter- and intra-specific differences in environmental responses. Growth and mycotoxin production of <i>F. graminearum</i> and <i>F. avenaceum</i> appeared favored under high temperature (≥25°C) and high water activity (≥0.97), whereas lower <i>a</i>_<i>w</i> levels (≥0.95) were also conducive for <i>F. poae</i> and <i>F. tricinctum</i>. A specific and unique behavior of <i>F. langsethiae</i> to lowest temperatures (≤20°C) was highlighted. Understanding the ecophysiological requirements of <i>Fusarium</i> species is crucial in the context of climate change, which is expected to worsen disease outbreaks. This study provides valuable knowledge for improving the reliability and robustness of FHB prediction models and anticipating the associated mycotoxin risk.IMPORTANCE<i>Fusarium</i> species pose a significant threat to major cereal crops, particularly wheat, by reducing yields and producing mycotoxins that are harmful to animals and humans. The prevalence of each <i>Fusarium</i> species is strongly influenced by environmental conditions, and climate changes have already been reported as responsible for shifts in pathogen populations, leading to changes in mycotoxin patterns. This study revealed distinct ecophysiological behaviors, including growth and mycotoxin production, of the five major <i>Fusarium</i> species infecting small grain cereals when exposed to varying temperature and water activity conditions. Our findings provide a valuable foundation for a deeper understanding of mycotoxin risk and for developing more effective mitigation strategies in the near future.</p>","PeriodicalId":8002,"journal":{"name":"Applied and Environmental Microbiology","volume":" ","pages":"e0183224"},"PeriodicalIF":3.9,"publicationDate":"2025-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144257213","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":"Isolation and characterization of a bacterium affiliated with the hitherto uncultured candidate phylum WOR-3 from a deep-sea hydrothermal fluid.","authors":"Koji Mori, Kohei Hidaka, Satoshi Tamazawa, Akira Hosoyama, Hideyuki Tamaki, Takeshi Kakegawa, Satoshi Hanada","doi":"10.1128/aem.00188-25","DOIUrl":"https://doi.org/10.1128/aem.00188-25","url":null,"abstract":"<p><p>A pure cultured representative, designated strain sy37, in the candidate WOR-3 lineage was obtained from a deep-sea hydrothermal fluid. This lineage was named as the candidate phylum, \"<i>Candidatus</i> Caldipriscota,\" \"<i>Candidatus</i> Hydrothermota,\" or \"<i>Candidatus</i> Stahliibacteriota,\" based on metagenome-assembled genomes of samples from various environments. The isolated strain was a thermophilic, microaerophilic, and chemoheterotrophic rod and obtained energy through aerobic/anaerobic respiration using oxygen and elemental sulfur. The strain could not use thiosulfate, sulfate, sulfite, fumarate, nitrate, nitrite, selenate, selenite, arsenate, ferric citrate, or ferrihydrite as an electron acceptor. Genomic annotation suggested that strain sy37 possesses a novel sulfur reduction mechanism. Among members of the WOR-3 lineage, only the group containing strain sy37 possessed the oxidative phosphorylation pathway with V-type ATPase and cytochrome <i>c</i> oxidase and may be capable of evolving to adapt to modern oxidative environments.</p><p><strong>Importance: </strong>Genome analysis from various environments has revealed the overall diversity of microorganisms. However, there are many lineages for which culture representatives do not yet exist, and the characteristics and ecological significance of many of these microorganisms remain unclear: the WOR-3 lineage is one of these and has been found in various environments through the 16S rRNA gene analysis. In recent years, the metagenome-assembled genomes have been determined from the environments. In this study, we report on the successful isolation of a thermophilic microaerobic chemoorganoheterotroph, strain sy37, which is phylogenetically belonging to the WOR-3 lineage, from a deep-sea hydrothermal environment for the first time.</p>","PeriodicalId":8002,"journal":{"name":"Applied and Environmental Microbiology","volume":" ","pages":"e0018825"},"PeriodicalIF":3.9,"publicationDate":"2025-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144257214","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":"From genes to function: regulation, maturation, and evolution of cytochrome <i>c</i> nitrite reductase in nitrate reduction to ammonium.","authors":"Krystina Hird, Julius O Campeciño, Eric L Hegg","doi":"10.1128/aem.00292-25","DOIUrl":"https://doi.org/10.1128/aem.00292-25","url":null,"abstract":"<p><p>The dissimilatory nitrate reduction to ammonium pathway converts nitrate to ammonium, a vital reaction in the global nitrogen cycle. The second step of the pathway is performed by cytochrome <i>c</i> nitrite reductase (NrfA), a soluble, periplasmic cytochrome responsible for the reduction of nitrite to ammonium. The pentaheme NrfA catalyzes this six-electron and eight-proton reduction of nitrite at a single active site with the help of its quinol oxidase partners. In this review, we discuss our current understanding of (i) the structure, homology, and evolution of both NrfA and its redox partners, (ii) the regulation of the <i>nrf</i> operon, and (iii) the maturation of NrfA proteins via unique cytochrome maturation pathways.</p>","PeriodicalId":8002,"journal":{"name":"Applied and Environmental Microbiology","volume":" ","pages":"e0029225"},"PeriodicalIF":3.9,"publicationDate":"2025-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144245957","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":"Identification of circulating human papillomavirus types through high-throughput sequencing of Canadian municipal and institutional wastewater samples.","authors":"Shayna J Giesbrecht, Samantha J Krosta, Rebecca Fox, Kurt Kolsun, Zoe Quill, Suzanne Gibbons, Aida Sivro, Paul Sandstrom, Chand S Mangat, Michael G Becker","doi":"10.1128/aem.00348-25","DOIUrl":"https://doi.org/10.1128/aem.00348-25","url":null,"abstract":"<p><p>Human papillomaviruses (HPVs) are a diverse group of viruses that infect human mucosal and cutaneous tissues, with a ubiquitous global distribution. Several types are classified as high-risk due to their association with cervical, anal, penile, and oropharyngeal cancers. Given its widespread prevalence and the limitations of clinical surveillance, HPV is an ideal candidate for wastewater-based testing (WBT), as a way to characterize circulating HPV types. Toward this goal, we utilized high-throughput Illumina-based amplicon sequencing targeting the conserved GP5+/GP6+ sites of HPV in wastewater samples collected from two urban treatment plants, two town sites, and three correctional facilities. Larger population catchments displayed greater diversity of HPV types in wastewater compared to institutional settings, reflecting differences in community composition and exposure. A total of 24 distinct HPV types were detected, all belonging to the alpha-papillomavirus genus, encompassing high- and low-risk types, types of unknown risk, and both cutaneous and mucosal types. Among these were six vaccine-preventable types, including HPV-16 and HPV-18, as well as probably carcinogenic types not routinely monitored in clinical settings, such as HPV-67, HPV-69, and HPV-73. These findings demonstrate the utility of WBT as a complementary tool to clinical testing, providing critical insights to inform cancer prevention strategies and evaluate the impact of vaccination programs.</p><p><strong>Importance: </strong>Human papillomavirus (HPV)-related cancers, including cervical, anal, penile, and oropharyngeal cancers, impose a significant economic burden on healthcare systems, with billions spent annually on treatment and management. This study reports the detection of HPV in Canadian wastewater, providing new insights into HPV circulation within communities. The findings highlight the ongoing prevalence of high-risk HPV types targeted by vaccines and the circulation of probable carcinogenic types, such as HPV-67, HPV-69, and HPV-73, which are not included in current clinical testing algorithms. Wastewater-based surveillance of HPV could complement clinical testing by capturing data on populations typically underrepresented in clinical settings. A clearer understanding of circulating HPV types can support public health efforts to promote cancer screening, monitor vaccination campaigns, and address gaps in prevention strategies. The continued development of wastewater-based testing systems hints toward a promising future for unbiased monitoring of community health.</p>","PeriodicalId":8002,"journal":{"name":"Applied and Environmental Microbiology","volume":" ","pages":"e0034825"},"PeriodicalIF":3.9,"publicationDate":"2025-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144224083","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":"The role of <i>Pantoea stewartii</i> subsp. <i>stewartii</i> leucine-responsive regulatory protein (Lrp) during maize xylem growth.","authors":"Wilson M Farthing, Abigail M Heimbach, Ann M Stevens","doi":"10.1128/aem.00853-25","DOIUrl":"https://doi.org/10.1128/aem.00853-25","url":null,"abstract":"<p><p>The bacterium <i>Pantoea stewartii</i> subsp. <i>stewartii</i> (<i>Pss</i>) causes Stewart's wilt disease in maize. <i>Pss</i> is introduced into maize via the corn flea beetle vector, <i>Chaetocnema pulicaria</i>, when beetle feces enter wounds created during feeding. The infection begins in the apoplast of the leaf where <i>Pss</i> causes leaf blight. Subsequently, the bacteria move to the xylem and form a biofilm, preventing water transport. This causes wilting and leads to necrosis, consequently affecting both crop yield and survival. A previous Tn-Seq experiment identified genes essential for <i>Pss in planta</i> survival. One essential gene, <i>lrp</i>, encodes the global transcription factor leucine-responsive regulatory protein (Lrp). The Lrp protein family is found across many bacterial and archaeal species where it regulates multiple critical physiological functions. In <i>Pss</i>, Lrp is known to positively control motility and capsule production, which are important for the <i>in planta</i> lifestyle and virulence of <i>Pss</i>. In this study, the genes within the <i>Pss</i> Lrp regulon were defined through bioinformatic analyses of RNA-Seq data that measured differential gene expression between wild-type <i>Pss</i> and a <i>∆lrp</i> strain grown <i>in planta</i>. Lrp was found to regulate genes involved in capsule biosynthesis and nitrogen-associated assimilation and metabolism. Biolog plates were subsequently used to link the regulatory role of Lrp with regard to <i>Pss</i> metabolism by examining the capacity of <i>Pss</i> to grow using sole carbon or nitrogen sources <i>in vitro</i>. Collectively, this work has provided insights into how <i>Pss</i> recognizes and exploits the maize xylem environment.IMPORTANCEThe bacterium <i>Pantoea stewartii</i> subsp. <i>stewartii</i> (<i>Pss</i>) causes Stewart's wilt disease in maize when it forms a biofilm in the xylem that prevents water flow. Little is known about how <i>Pss</i> is able to colonize and grow within the maize xylem. Previous work identified the Lrp regulatory protein as being important for the survival of the bacterium inside maize. This study determined the genes whose transcription is under Lrp control and predicted the physiological functions associated with those genes to learn more about the bacterial growth inside the plant. The ability to transport and metabolize organic compounds containing nitrogen and the ability to produce capsule were found to be regulated by Lrp. Additional laboratory experiments demonstrated that Lrp also controls the metabolism of certain sole carbon and nitrogen sources. Together, these findings provide new insights into how Lrp enables <i>Pss</i> to respond to nutrient availability in the maize xylem environment.</p>","PeriodicalId":8002,"journal":{"name":"Applied and Environmental Microbiology","volume":" ","pages":"e0085325"},"PeriodicalIF":3.9,"publicationDate":"2025-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144224084","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":"Correction for Van Fossen et al., \"Profiling sorghum-microbe interactions with a specialized photoaffinity probe identifies key sorgoleone binders in <i>Acinetobacter pittii</i>\".","authors":"Elise M Van Fossen, Jared O Kroll, Lindsey N Anderson, Andrew D McNaughton, Daisy Herrera, Yasuhiro Oda, Andrew J Wilson, William C Nelson, Neeraj Kumar, Andrew R Frank, Joshua R Elmore, Pubudu Handakumbura, Vivian S Lin, Robert G Egbert","doi":"10.1128/aem.00810-25","DOIUrl":"https://doi.org/10.1128/aem.00810-25","url":null,"abstract":"","PeriodicalId":8002,"journal":{"name":"Applied and Environmental Microbiology","volume":" ","pages":"e0081025"},"PeriodicalIF":3.9,"publicationDate":"2025-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144224081","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":"Diverse <i>Sulfuriferula</i> spp. from sulfide mineral weathering environments oxidize ferrous iron and reduced inorganic sulfur compounds.","authors":"Kathryn K Hobart, Gabriel M Walker, Joshua M Feinberg, Jake V Bailey, Daniel S Jones","doi":"10.1128/aem.00216-25","DOIUrl":"https://doi.org/10.1128/aem.00216-25","url":null,"abstract":"<p><p>Microorganisms are important catalysts for the oxidation of reduced inorganic sulfur compounds. One environmentally important source of reduced sulfur is metal sulfide minerals that occur in economic mineral deposits and mine waste. Previous research found that <i>Sulfuriferula</i> spp. were abundant and active in long-term weathering experiments with simulated waste rock and tailings from the Duluth Complex, Northern Minnesota. We, therefore, isolated several strains of <i>Sulfuriferula</i> spp. from these long-term experiments and characterized their metabolic and genomic properties to provide insight into microbe-mineral interactions and the microbial biogeochemistry in these and other moderately acidic to circumneutral environments. The <i>Sulfuriferula</i> strains are all obligate chemolithoautotrophs capable of oxidizing inorganic sulfur compounds and ferrous iron. The strains grew over different pH ranges, but all grew between pH 4.5 and 7, matching the weathering conditions of the Duluth Complex rocks. All strains grew on the iron-sulfide mineral pyrrhotite (Fe_{1 - <i>x</i>}S, 0 < <i>x</i> < 0.125) as the sole energy source, as well as hydrogen sulfide and thiosulfate, which are products of sulfide mineral breakdown. Despite their metabolic similarities, each strain encodes a distinct pathway for the oxidation of reduced inorganic sulfur compounds as well as differences in nitrogen metabolism that reveal diverse genomic capabilities among the group. Our results show that <i>Sulfuriferula</i> spp. are primary producers that likely play a role in sulfide mineral breakdown in moderately acidic to circumneutral mine waste, and the metabolic diversity within the genus may explain their success in sulfide mineral-rich and other sulfidic environments.</p><p><strong>Importance: </strong>Metal sulfide minerals, such as pyrite and pyrrhotite, are one of the main sources of reduced sulfur in the global sulfur cycle. The chemolithotrophic microorganisms that break down these minerals in natural and engineered settings are catalysts for biogeochemical sulfur cycling and have important applications in biotechnological processes such as biomining and bioremediation. <i>Sulfuriferula</i> is a recently described genus of sulfur-oxidizing bacteria that are abundant primary producers in diverse terrestrial environments, including waste rock and tailings from metal mining operations. In this study, we explored the genomic and metabolic properties of new isolates from this genus, and the implications for their ecophysiology and biotechnological potential in ore and waste from economic mineral deposits.</p>","PeriodicalId":8002,"journal":{"name":"Applied and Environmental Microbiology","volume":" ","pages":"e0021625"},"PeriodicalIF":3.9,"publicationDate":"2025-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144224082","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}