Frontiers in Microbiology最新文献

{"title":"Unlocking associative nitrogen fixation in Poaceae: molecular mechanisms, regulatory constraints, and pathways to sustainable productivity.","authors":"Qian Nong, Qiang Liang, Xing Huang, Li Lin, Anjali Chandrol Solanki, Mukesh Kumar Malviya, Manoj Kumar Solanki, Krishan K Verma, Changning Li","doi":"10.3389/fmicb.2026.1922705","DOIUrl":"https://doi.org/10.3389/fmicb.2026.1922705","url":null,"abstract":"<p><p>Biological nitrogen fixation (BNF) is a sustainable and environmentally friendly approach to nitrogen assimilation that extends beyond leguminous plants, where efficient nitrogen fixation occurs. Poaceae crops can also obtain nitrogen through associative nitrogen fixation (ANF) mediated by endophytic and rhizospheric diazotrophs, which typically contributes 10-30 kg N ha^-1 yr.^-1 to cereal crops, i.e., wheat, maize, rice, though certain tropical grasses, such as sugarcane may achieve up to 40-50 kg N ha^-1 yr.^-1 under optimal conditions. This review synthesizes recent advancements of ANF research across Poaceae crops, providing comprehensive analysis of their functional mechanisms. It explores the underlying mechanisms regulating ANF and assesses key factors influencing nitrogenase activity, including oxygen sensitivity, external nitrogen availability, and energy constraints. Furthermore, it discusses advanced strategies, such as genetic engineering of nitrogen-fixing microbes, host plant metabolic modifications, and optimized agronomic strategies to enhance nitrogen fixation efficacy. This review establishes a robust framework for sustainable crop production and long-term agricultural productivity by integrating molecular, physiological, and ecological perspectives. The major challenges of climate change, regional fertilizer restrictions, and achieving sustainable agricultural intensification collectively underscore the urgent need for biologically based nitrogen management strategies in cereal cropping systems.</p>","PeriodicalId":12466,"journal":{"name":"Frontiers in Microbiology","volume":"17 ","pages":"1922705"},"PeriodicalIF":5.8,"publicationDate":"2026-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13678380/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149223721","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Untargeted metabolomics reveals distinct metabolic profiles and putative bioactive metabolites in cell-free supernatants of food-grade microorganisms.","authors":"Denise Drago, Luca Marini, Eleonora Bafile, Federica Federici, Radmila Pavlovic, Marynka Ulaszewska, Gianfranco Frigerio, Laura Manna, Annapaola Andolfo","doi":"10.3389/fmicb.2026.1854827","DOIUrl":"10.3389/fmicb.2026.1854827","url":null,"abstract":"<p><p>Over the past decade, the understanding of the role of microorganisms in health and disease has expanded considerably, with many of the beneficial effects traditionally attributed to probiotics now also being associated with their metabolites, collectively referred to as postbiotics. In this context, postbiotics are increasingly being explored as complementary components of broader microbiome-centered strategies. Fermentation supernatants are commonly regarded as industrial by-products; however, they contain a diverse repertoire of microbially derived metabolites with potential biological relevance. The valorization of these fermentation streams therefore represents a promising strategy for identifying novel compounds capable of modulating host physiology. Five food-grade microorganisms-<i>Lactobacillus amylovorus</i> SGL 14, <i>Bifidobacterium breve</i> SGB 01, <i>Lentilactobacillus kefiri</i> SGL 13, <i>Lactiplantibacillus plantarum</i> SGL 07, and <i>Ligilactobacillus salivarius</i> SGL 03-were cultured under standardized conditions, and their cell-free supernatants were characterized using untargeted metabolomics to identify differential metabolic profiles. Each strain displayed a distinctive metabolomic signature enriched in metabolites previously associated in the literature with potential biological activities. Collectively, the identified compounds have been linked to antimicrobial, immunomodulatory, neuroactive, antioxidant, epithelial-supportive, and metabolic functions. However, the present study did not include direct functional validation of these activities, and the proposed biological relevance of the detected metabolites should therefore be considered putative and inferred from previous literature evidence. Overall, untargeted metabolomics/lipidomics revealed that fermentation media derived from food-grade microorganisms represent a valuable and underexplored source of multifunctional metabolites with potential postbiotic applications. These findings support the concept of valorizing microbial fermentation by-products as sustainable reservoirs of biologically relevant molecules within a circular bioeconomy framework. In industrial settings, fermentation broths traditionally considered waste streams may be recovered and repurposed, potentially reducing disposal costs and environmental impact. Furthermore, optimization of fermentation processes prior to large-scale metabolite production will be essential to maximize yield, improve process efficiency, and support their future development for nutraceutical and health-related applications.</p>","PeriodicalId":12466,"journal":{"name":"Frontiers in Microbiology","volume":"17 ","pages":"1854827"},"PeriodicalIF":5.8,"publicationDate":"2026-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13673657/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149215523","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Proteomic adaptation of the hypervirulent pandemic <i>Vibrio parahaemolyticus</i> ST36 lineage to salinity and temperature stress.","authors":"Eloisa González-Vidal, Sara Eslava-Alcón, Estefanía Jurado-Tarifa, Inmaculada Guerrero-Lozano, MaCarmen Durán-Ruiz, Manuel A Rodriguez-Iglesias","doi":"10.3389/fmicb.2026.1947974","DOIUrl":"10.3389/fmicb.2026.1947974","url":null,"abstract":"<p><p><i>Vibrio parahaemolyticus</i> is a halophilic Gram-negative bacterium widely distributed in marine and estuarine ecosystems, and a leading cause of seafood-borne gastroenteritis worldwide. Among its genetic lineages, sequence type 36 (ST36) has emerged as a pandemic clone with remarkable environmental persistence and global dissemination. Its pathogenicity is closely associated with environmental conditions, particularly salinity and temperature, which modulate the expression of virulence factors, stress-response proteins, and metabolic pathways. In this study, we investigated the differential protein expression profiles of <i>Vibrio parahaemolyticus</i> under controlled salinity (1 and 3%) and temperature (20 °C, 31 °C, and 37 °C) using a label free-quantitative (LFQ) proteomic approach. Our results demonstrate that the <i>Vibrio parahaemolyticus</i> proteome is dynamically and non-linearly modulated by specific combinations of salt and heat rather than a simple additive effect of these factors. Temperature-salinity interactions drove most expression changes (2,144 proteins), with temperature acting as the primary driver (1,302 proteins). Proteome changes peaked mostly at 31 °C for salinity variations and at 3% salinity for temperature shifts, each affecting ~80% of proteins, though specific responses ultimately depended on the nature of individual proteins. Functionally, protein changes were representative of a shift from relatively balanced cellular metabolism at mild stress conditions toward respiratory remodeling, central-carbon reorganization, ATP production, and redox defense under elevated salinity and temperature. Additionally, virulence-, toxin-, motility-, chemotaxis-, and defense-associated proteins were distributed across several trend clusters. Overall, the proteomic patterns detected in <i>Vibrio parahaemolyticus</i> in response to temperature and salinity fluctuations reveal a coordinated regulation of virulence, stress-response, and metabolic proteins that underpins its ecological fitness. Beyond these biological insights, the proteomic workflow employed provides a robust methodological framework for studying bacterial stress adaptation. Ultimately, these findings deepen our understanding of the pathogen dynamics under climate change and for improving seafood safety and risk management. Future research is warranted to experimentally validate the molecular pathways identified and confirm their functional roles in adaptation.</p>","PeriodicalId":12466,"journal":{"name":"Frontiers in Microbiology","volume":"17 ","pages":"1947974"},"PeriodicalIF":5.8,"publicationDate":"2026-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13672198/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149215467","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Vaginal <i>Lactobacillus paragasseri</i> may attenuate fluconazole-resistant phenotypes in the subset of <i>Candida albicans</i> isolates and shows potential as a probiotic adjunct in antifungal therapy.","authors":"Qiuyue Wang, Hua Wang, Huirong Pan, Zhongyan Xu, Qi Cui, Huihai Zhao, Keran Jia, Fukun Wang","doi":"10.3389/fmicb.2026.1951876","DOIUrl":"10.3389/fmicb.2026.1951876","url":null,"abstract":"&lt;p&gt;&lt;strong&gt;Introduction: &lt;/strong&gt;&lt;i&gt;Candida albicans&lt;/i&gt; is the predominant etiological agent of vulvovaginal candidiasis (VVC). Fluconazole (FLU), a first-line azole antifungal agent, has encountered growing resistance among vaginal isolates of &lt;i&gt;C. albicans&lt;/i&gt; due to prolonged, high-dose clinical administration. The development of such drug resistance arises from the synergistic interplay of multiple factors, with key mechanisms including enhanced biofilm formation, overexpression of drug efflux pump genes, and structural alterations in target enzymes driven by mutations in the &lt;i&gt;ERG11&lt;/i&gt; gene. &lt;i&gt;Lactobacilli&lt;/i&gt;, the dominant commensal probiotics in the vaginal microbiota, are known to inhibit biofilm formation by &lt;i&gt;C. albicans&lt;/i&gt;, a process closely linked to the development of antifungal resistance. Consequently, vaginal lactobacilli may serve as a pharmacological adjuvant to enhance the antifungal efficacy of fluconazole against &lt;i&gt;C. albicans&lt;/i&gt;. While existing research has primarily focused on the inhibitory effects of &lt;i&gt;Lactobacilli&lt;/i&gt; on &lt;i&gt;C. albicans&lt;/i&gt; proliferation, investigations into their impact on antifungal resistance remain limited.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Methods: &lt;/strong&gt;We investigate the impact of vaginal &lt;i&gt;L. paragasseri&lt;/i&gt; on fluconazole-resistance phenotypes in a subset of clinical fluconazole-resistant &lt;i&gt;C. albicans&lt;/i&gt; isolates. Guided by established fluconazole-resistance mechanisms, we first screened fluconazole resistant &lt;i&gt;C. albicans&lt;/i&gt; isolates by assessing biofilm formation capacity, drug efflux pump gene expression, and &lt;i&gt;ERG11&lt;/i&gt; gene mutations and mRNA expression. Next, analysis of the vaginal &lt;i&gt;Lactobacillus&lt;/i&gt; composition in VVC patients and healthy controls showed a nominal, non-significant trend toward lower &lt;i&gt;L. paragasseri&lt;/i&gt; detection in VVC-affected women. Motivated by this trend and by prior evidence that &lt;i&gt;Lactobacilli&lt;/i&gt; can modulate antifungal-resistance phenotypes, we examined whether &lt;i&gt;L. paragasseri&lt;/i&gt; modulates fluconazole-resistance in clinically derived &lt;i&gt;C. albicans&lt;/i&gt; isolates through functional assays. Subsequent functional assessments, including standard antifungal susceptibility testing, biofilm formation assays, and drug efflux pump gene expression analyses.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Results: &lt;/strong&gt;Vaginal &lt;i&gt;L. paragasseri&lt;/i&gt; can attenuate fluconazole-resistant phenotypes in the tested subset of clinical fluconazole-resistant &lt;i&gt;C. albicans&lt;/i&gt; isolates. In a murine vulvovaginal candidiasis model, adjunctive treatment with &lt;i&gt;L. paragasseri&lt;/i&gt; provided adjuvant benefit when added to fluconazole therapy, reducing vaginal &lt;i&gt;C. albicans&lt;/i&gt; colonization and alleviating infection-associated tissue damage. These in-vivo observations constitute preliminary pre-clinical evidence.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Discussion: &lt;/strong&gt;These findings demonstrate that vaginal L. paragasseri holds promising potential as a probiotic adjunctive therapy for &lt;i&gt;C. albicans&lt;/i&gt;-induced VVC, offering novel i","PeriodicalId":12466,"journal":{"name":"Frontiers in Microbiology","volume":"17 ","pages":"1951876"},"PeriodicalIF":5.8,"publicationDate":"2026-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13672589/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149215476","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"High-fiber diet altered gut microbiota, improved glycemic control, and reduced body weight in newly diagnosed type 2 diabetes and obesity.","authors":"Yan Li, Yalei Liu, Yiqi Chen, Baoyu Xiang, Huaqing Fu, Han Pan, Ting Xu, Zhaojie Li, Yajie Zhang, Huijuan Yuan, Chenhong Zhang","doi":"10.3389/fmicb.2026.1972983","DOIUrl":"10.3389/fmicb.2026.1972983","url":null,"abstract":"<p><p>Type 2 diabetes and obesity commonly coexist, making glycemia and body weight both central treatment goals. Few trials have directly compared a high-fiber dietary intervention with metformin. The factors associated with individual responses to high-fiber diet also remain unclear. In this single-center, open-label, head-to-head clinical trial, 48 adults with newly diagnosed type 2 diabetes and overweight or obesity were randomized to a high-fiber dietary intervention without glucose-lowering medication (<i>n</i> = 36) or metformin (<i>n</i> = 12) monotherapy for 84 days; 46 completed the trial. Clinical outcomes and 184 fecal samples were assessed longitudinally using shotgun metagenomic and metabolite profiling. At Day 84, the high-fiber group had greater reductions in glycated hemoglobin and body mass index and lower glycemic variability than the metformin group. The diet altered gut microbiota by Day 28, enriching genomes from <i>Bifidobacterium</i> and <i>Lactobacillus</i> and depleting genomes from <i>Bilophila wadsworthia</i>, but metformin produced little detectable microbiota change. These changes included increased acetate-production functions and decreased hydrogen sulfide-production functions; fecal hydrogen sulfide was lower at Days 28 and 56, although short-chain fatty acid concentrations did not differ between groups at matched time points. Within the high-fiber group, participants with increased fecal acetate (25 of 34) had larger glycated hemoglobin reductions at Days 28 and 56, and baseline microbial features differed between acetate-response subgroups. These findings support high-fiber diet as a non-pharmacologic strategy for diabesity, with baseline microbial features as candidate markers of response. <b>Clinical trial registration:</b> ChiCTR-INR-17011752.</p>","PeriodicalId":12466,"journal":{"name":"Frontiers in Microbiology","volume":"17 ","pages":"1972983"},"PeriodicalIF":5.8,"publicationDate":"2026-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13672211/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149215210","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Bacterial diversity in gut compartments of <i>Tomicus brevipilosus</i>: from shoot-boring preconditioning of <i>Pinus yunnanensis</i> to trunk-boring reproduction.","authors":"Mei-Ru Yang, Hua Xie, Shun-Yan Dong, Zong-Bo Li, Wei-Nan Kang","doi":"10.3389/fmicb.2026.1914356","DOIUrl":"10.3389/fmicb.2026.1914356","url":null,"abstract":"<p><strong>Background: </strong>Gut bacteria are critically important to bark beetles, especially under environmental fluctuations. <i>Tomicus brevipilosus</i> undergoes a niche shift from shoot-boring (which weakens <i>Pinus yunnanensis</i>) to trunk-boring for reproduction. The relationship between this transition and the gut microbiota remains to be elucidated.</p><p><strong>Methods: </strong>Using 16S rRNA sequencing, we characterized gut bacterial communities across adult feeding phase, sexes, and intestinal compartments.</p><p><strong>Results: </strong>The alimentary canal was composed of six morphologically distinguishable regions, to which Malpighian tubules were affixed. At the shoot-boring stage, no clear compartmentalization was observed in either sex, and no particular genus emerged as prominently associated. In trunk-boring adults, females undertake oviposition, whereas males evacuate excreta and food residues from the burrow entrance using their abdominal apex and elytral declivity. During the trunk-boring phase, compartment-specific differentiation was evident: the male rectum exhibited the highest bacterial ASV richness and complexity, harboring the greatest number of unique bacterial taxa at all taxonomic levels (phylum to genus), with significant enrichment of two short-chain fatty acid (SCFA)-producing genera (<i>Dietzia</i> and <i>Acinetobacter</i>), suggesting a potential defensive role against gallery pathogens. In contrast, female trunk-boring adults showed no clear gut compartmentalization, although the genera <i>Delftia</i> and <i>Halomonas</i> may contribute to cellulose breakdown and thereby facilitate reproduction. These functional inferences, however, await direct experimental confirmation. Interaction analyses further revealed that gut bacterial communities across intestinal segments varied significantly with both stage and sex.</p><p><strong>Conclusion: </strong>These stage- and sex-specific patterns likely reflect differing physiological and behavioral demands during the niche shift. Our findings demonstrate that this transition drives structural alterations in gut bacterial communities across both compartments and sexes, and provide a basis for future exploration of symbiont-based management strategies for this destructive forest pest.</p>","PeriodicalId":12466,"journal":{"name":"Frontiers in Microbiology","volume":"17 ","pages":"1914356"},"PeriodicalIF":5.8,"publicationDate":"2026-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13672192/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149215536","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Plant compartment and understory habitat jointly shape endophytic bacterial communities in <i>Monochasma savatieri</i>.","authors":"Yuling Zou, Fengqing Li, Suzhen Liu, Wendi Lan, Mansheng Zeng, Guisheng Luo, Wei Huang, Lili Shen, Baolian Zhang, Shutong Sang","doi":"10.3389/fmicb.2026.1930478","DOIUrl":"10.3389/fmicb.2026.1930478","url":null,"abstract":"<p><strong>Introduction: </strong><i>Monochasma savatieri</i> is a rare medicinal plant endemic to China that currently faces extinction, with wild-simulated understory cultivation representing a key conservation strategy. Endophytic bacteria play important roles in nutrient acquisition and environmental adaptation of hemiparasitic plants; however, how the understory environments influence above- and belowground endophytic bacterial communities remains poorly understood.</p><p><strong>Methods: </strong>We collected soil and plant tissue samples from four contrasting understory habitats (<i>Pinus massoniana</i>, <i>Camellia oleifera</i>, <i>Phyllostachys edulis</i>, and <i>Gardenia jasminoides</i>). The endophytic bacterial communities were characterized by 16S rRNA gene sequencing. The soil physicochemical properties were measured to identify environmental drivers. Multivariate statistics, including permutational multivariate analysis of variance (PERMANOVA), redundancy analysis (RDA), and Mantel tests, were applied to link the community variation with environmental factors.</p><p><strong>Results: </strong>Permutational multivariate analysis of variance revealed that the type of plant tissue, habitat, and their interaction (all <i>p</i> < 0.001) significantly shaped the endophytic community structure. Belowground tissues generally harbored higher diversity than aboveground tissues, although this pattern was habitat-dependent. Each habitat enriched distinct bacterial genera. Functional predictions showed a complementary pattern: aboveground communities were enriched in sensing-related pathways, whereas belowground communities showed higher abundances of degradation-associated pathways. RDA identified the soil total and available potassium as strong environmental correlates of community differentiation.</p><p><strong>Discussion: </strong>The findings of this study demonstrate that plant compartment and understory habitat jointly shape endophytic bacterial communities in <i>M. savatieri</i>, with potassium availability as a key correlate. However, because each habitat was represented by a single geographic site, the vegetation type is confounded with the location, climate, and soil properties; therefore, our inferences are correlative rather than causal. Within these constraints, the findings help identify candidate taxa and environmental associations that provide testable hypotheses for future cultivation and microecological research on this rare medicinal plant.</p>","PeriodicalId":12466,"journal":{"name":"Frontiers in Microbiology","volume":"17 ","pages":"1930478"},"PeriodicalIF":5.8,"publicationDate":"2026-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13672331/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149215546","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"7-O-sulfonation redirects luteolin's target preference from furin to NS2B/NS3 and enhances anti-dengue activity.","authors":"Huini Chen, Zizhao Lao, Yuhang Huo, Liangwen Yu, Wen Zhou, Geng Li","doi":"10.3389/fmicb.2026.1931544","DOIUrl":"10.3389/fmicb.2026.1931544","url":null,"abstract":"<p><strong>Background: </strong>Dengue virus (DENV) infection remains a global health threat with no approved small-molecule antiviral for clinical use. Luteolin, a natural flavonoid, exhibits anti-dengue activity but suffers from poor solubility and moderate potency. The 7-O position is the primary site of metabolic glucuronidation, whereas the 5-O position is sequestered by intramolecular hydrogen bonding, offering structurally distinct positions for derivatization.</p><p><strong>Methods: </strong>Five site-selective derivatives of luteolin (three 5-O- and two 7-O-substituted) were synthesized. Their anti-DENV activity was evaluated in Vero cells by qRT-PCR (measuring viral RNA abundance) and plaque assays, and cytotoxicity was determined using the CCK8 method. For mechanistic exploration, enzymatic inhibition kinetics against NS2B/NS3 and furin were measured, and target engagement was further assessed via molecular docking and cellular thermal shift assays (CETSA).</p><p><strong>Results: </strong>Among the derivatives, compound 5, bearing a 4-fluorobenzenesulfonyl group at the 7-O position, exhibited the most potent anti-DENV activity (EC₅₀ = 0.46 μM) and the highest selectivity index (SI = 28.5), representing an 18-fold increase in antiviral potency over luteolin. In enzymatic assays, compound 5 showed preferential inhibition of the viral NS2B/NS3 protease (<i>K</i> _<i>i</i> = 11.54 μM) over the host furin (<i>K</i> _<i>i</i> = 93 μM). Molecular docking and thermal stabilization assays provided correlative evidence supporting target engagement with both proteases.</p><p><strong>Conclusion: </strong>Site-selective 7-O-sulfonation of luteolin yields compound 5, a derivative with improved anti-DENV activity and selectivity that shows preferential NS2B/NS3 inhibition in enzymatic assays. This study provides a structural framework for the further optimization of flavonoid-based antiviral agents.</p>","PeriodicalId":12466,"journal":{"name":"Frontiers in Microbiology","volume":"17 ","pages":"1931544"},"PeriodicalIF":5.8,"publicationDate":"2026-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13672209/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149215500","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Alfalfa fields with different stand ages alters soil inorganic nitrogen dynamics through shifts in nitrogen-cycling functional genes across growth stages.","authors":"Delong Tian, Mingzi Lv, Guoshuai Wang, Ting Fan","doi":"10.3389/fmicb.2026.1958461","DOIUrl":"10.3389/fmicb.2026.1958461","url":null,"abstract":"<p><strong>Introduction: </strong>Alfalfa cultivation is associated with soil nitrogen availability and microbial nitrogen-cycling functional potential. However, how soil inorganic nitrogen and nitrogen-cycling functional genes vary with alfalfa stand age across growth stages remains unclear.</p><p><strong>Methods: </strong>Using a chronosequence approach, we investigated soil inorganic nitrogen and nitrogen-cycling functional genes in a maize-field control (CK) and 2-, 3-, 4-, and 7-year-old alfalfa fields (T1-T4) during the regreening, flowering, and maturity-harvest stages. Soil <math> <msubsup><mrow><mtext>NO</mtext></mrow> <mrow><mn>3</mn></mrow> <mrow><mo>-</mo></mrow> </msubsup> </math> -N and <math> <msubsup><mrow><mtext>NH</mtext></mrow> <mrow><mn>4</mn></mrow> <mrow><mo>+</mo></mrow> </msubsup> </math> -N concentrations and TPM-normalized abundances of nitrogen-cycling functional genes were determined. Correlation analysis, PERMANOVA, and structural equation modeling (SEM) were used to examine their relationships.</p><p><strong>Results: </strong>Soil <math> <msubsup><mrow><mtext>NO</mtext></mrow> <mrow><mn>3</mn></mrow> <mrow><mo>-</mo></mrow> </msubsup> </math> -N and <math> <msubsup><mrow><mtext>NO</mtext></mrow> <mrow><mn>4</mn></mrow> <mrow><mo>+</mo></mrow> </msubsup> </math> -N concentrations differed significantly among stand ages and generally exhibited unimodal patterns, with the highest observed values in the 4-year field (T3) and lower values in the 7-year field (T4). The abundances of genes involved in nitrification, denitrification, and nitrate reduction also varied with stand age and showed growth-stage-specific patterns. Growth stage explained a greater proportion of variation in nitrogen-cycling gene profiles than stand age, although stand age was also significantly associated with these profiles. The relationships between functional genes and soil inorganic nitrogen varied among growth stages. SEM analysis suggested that growth stage was the primary factor associated with variation in nitrogen-cycling gene groups. Nitrification-related genes were positively correlated with soil inorganic nitrogen, whereas nitrate reduction-related genes showed negative correlations.</p><p><strong>Conclusion: </strong>Overall, the 4-year alfalfa field exhibited the highest observed soil inorganic nitrogen concentrations, while this pattern was less evident in the 7-year field. These findings indicate that soil nitrogen status and nitrogen-cycling functional genes vary jointly with alfalfa stand age and growth stage. Nitrogen-cycling functional genes may serve as potential indicators of soil nitrogen status, although further experimental studies are needed to verify these relationships.</p>","PeriodicalId":12466,"journal":{"name":"Frontiers in Microbiology","volume":"17 ","pages":"1958461"},"PeriodicalIF":5.8,"publicationDate":"2026-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13672546/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149215504","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Formulation, physicochemical characterization, and antimicrobial evaluation of drug-loaded essential oil microemulsions against Methicillin-resistant <i>Staphylococcus aureus</i> -associated diabetic foot ulcer infections.","authors":"Disha Pramanick, Natarajan Chandrasekaran","doi":"10.3389/fmicb.2026.1906281","DOIUrl":"10.3389/fmicb.2026.1906281","url":null,"abstract":"<p><p>Diabetes Mellitus, a leading endocrine disorder characterized by persistent hyperglycemia, ischemia, and neuropathy, causes ulcerative wounds that are often colonized by multidrug-resistant pathogens, such as Methicillin-resistant <i>Staphylococcus aureus</i> (MRSA), which exacerbate wound infections and can lead to complications such as sepsis and necrosis in Diabetic Foot Ulcers (DFU). This study aims to formulate phytochemical-based nanovesicle carriers for potential wound-healing applications to retain the therapeutic effects of antimicrobial compounds with their localized delivery. This investigation develops microemulsions containing Eugenol, Clove, and Cinnamon oils to encapsulate Vancomycin and Methicillin, preserving their antibacterial activity while providing sustained delivery to the site of action. Microemulsions tested for thermodynamic stability, DLS, zeta potential, pH, FTIR, and TEM, showed optimal hydrodynamic size and PDI (within 30 nm and 0.5), a more negative zeta potential of around -19 mV, and an acidic pH. FTIR of blank emulsions against drug modifications confirmed successful drug incorporation, and TEM showed spherical-oval morphology. Antimicrobial testing using AST, MIC, Antibiofilm, Checkerboard, and Time-kill assays showed that drug-loaded emulsions provided measurable <i>in vitro</i> antibacterial activity against the tested clinical MRSA isolates, with activity varying by formulation and isolate (Eug-Van in MRSA-CI 1 and Clo-Van in MRSA-CI 2). Meanwhile, for Methicillin formulations, Clo-Met showed measurable inhibition against both tested isolates. Release kinetics revealed that drug-loaded emulsions showed sustained, diffusion-controlled release of the active therapeutics - Vancomycin and Methicillin over 24 h, with slowly increasing concentrations initially, followed by a plateau with maximum release in the case of Eug-Van microemulsion. These results demonstrate the considerable potential of these drug-loaded microemulsions as advanced nanocarrier systems for localized antimicrobial delivery in MRSA-colonized DFU infections.</p>","PeriodicalId":12466,"journal":{"name":"Frontiers in Microbiology","volume":"17 ","pages":"1906281"},"PeriodicalIF":5.8,"publicationDate":"2026-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13672633/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149215458","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}