BMC Microbiology最新文献

{"title":"Antibacterial and anti-virulence activity of the repurposed agent SX-682 against Staphylococcus aureus.","authors":"Haining Wang, Junhua Ma, Chengchun Chen, Yuqing Xia, Bao Chai, Zhijian Yu, Zewen Wen, Guiqiu Li, Ying Wei","doi":"10.1186/s12866-026-05104-6","DOIUrl":"https://doi.org/10.1186/s12866-026-05104-6","url":null,"abstract":"<p><strong>Background: </strong>Methicillin-resistant Staphylococcus aureus (MRSA) has become one of the most prevalent drug-resistant pathogens in many countries, posing a serious threat to global healthcare. Consequently, there is an urgent need to develop novel antibacterial agents.</p><p><strong>Objectives: </strong>This study aimed to evaluate the antibacterial and antibiofilm activities of SX-682-an orally bioavailable allosteric inhibitor of CXCR1/2-against S. aureus and to elucidate its underlying mechanisms.</p><p><strong>Results: </strong>Our findings demonstrate that SX-682 exhibits potent antibacterial activity against S. aureus, with minimum inhibitory concentration (MIC) values ranging from 8 to 16 µg/mL. Time-kill curves revealed a concentration-dependent bactericidal effect. Sub-inhibitory concentrations of SX-682 significantly inhibited the formation of S. aureus biofilms and effectively eradicated preformed mature biofilms. SX-682 enhances the membrane permeability of S. aureus and causes depolarization of the membrane potential, thereby damaging the integrity of the bacteria. By suppressing hemolytic activity and staphyloxanthin biosynthesis, SX-682 reduced the virulence of S. aureus. Additionally, proteomic analysis revealed that SX-682 treatment induced dysregulated expression of proteins in S. aureus, including SasG, FnbA, SdrC, SdrD, SaeR, SaeS, and SarX, which are associated with bacterial biofilm formation, bacterial virulence, and amino acid metabolism. Notably, in a murine model of MRSA-infected skin wounds, SX-682 significantly accelerated wound healing.</p><p><strong>Conclusions: </strong>Collectively, these findings highlight the considerable antibacterial and antibiofilm efficacy of SX-682 against S. aureus, supporting its potential as a promising therapeutic candidate for preventing and treating S. aureus infections.</p>","PeriodicalId":9233,"journal":{"name":"BMC Microbiology","volume":" ","pages":""},"PeriodicalIF":4.2,"publicationDate":"2026-05-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147863810","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":"Contact-mediated bacterial transmission and infection risk dynamics in a newly opened hospital ward.","authors":"Liyun An, Xiaonan Liu, Xiao Li, Yixuan Chu, Xiaoqiang Sun, Junsheng Chu, Yong Nie","doi":"10.1186/s12866-026-05030-7","DOIUrl":"https://doi.org/10.1186/s12866-026-05030-7","url":null,"abstract":"<p><p>The hospital microbiome significantly influences patient recovery and clinical outcomes. However, the dynamics of microbial colonization and transmission following initial patient occupancy remain poorly understood. Here, we employed 16 S rRNA gene amplicon sequencing of the V3-V4 region (Illumina platform) to investigate bacterial community dynamics on surfaces within neurosurgery ward and patients as a new hospital became operational. Our results showed that bacterial colonization in hospital wards follows distinct site-specific patterns, after hospital opening, alpha diversity was significantly increased on floors and drawer handles but decreased on bedrails and faucet handles compared to preopening. Beta diversity analysis showed that surfaces frequently contacted by patients exhibited the greatest compositional turnover, such as bedrails, drawer handles, and faucet handles, bacterial communities in after-opening were more homogeneous across sites than preopening, indicating potential bacterial transmission. Moreover, we found that following patient admission, patient hand-derived microbiomes exert a significant influence on the bacterial communities in hospital wards, with a particularly pronounced impact on bedrails. Additionally, the potential pathogenic potential of the microbial community at the taxonomic level of bedrails in post-opening was significantly higher than preopening, which does not reflect direct clinical infection risk. Taken together, these findings underscore the critical role of human contact in shaping hospital microbiomes and highlight the importance of targeted infection control strategies to mitigate potential pathogen transfer.</p>","PeriodicalId":9233,"journal":{"name":"BMC Microbiology","volume":" ","pages":""},"PeriodicalIF":4.2,"publicationDate":"2026-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147856009","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":"Phenotypic and genotypic characterization of clinical plasmid-mediated quinolone resistance (PMQR) and extended-spectrum beta-lactamase (ESBL)-producing Enterobacterales in two healthcare facilities in Douala, Cameroon.","authors":"Giresse Wilfried Guemkam, Luria Leslie Founou, Patrice Landry Koudoum, Megane Daina Foueyem, Brice Davy Dimani, Medi Sike Christiane, Michel Noubom, Raspail Carrel Founou","doi":"10.1186/s12866-026-05118-0","DOIUrl":"https://doi.org/10.1186/s12866-026-05118-0","url":null,"abstract":"<p><strong>Background: </strong>The emergence and escalation of antibiotic resistance in community and hospital settings remain a major public health concern worldwide. The co-occurrence of fluoroquinolone resistance in extended-spectrum β-lactamase-producing Enterobacterales (ESBL-E), which are responsible for life-threatening infectious diseases, poses a critical threat, leading to increase therapeutic costs, prolonged hospital stays, and higher mortality rates, particularly in low- and middle-income countries (LMICs) like Cameroon. Given the lack of data regarding the co-occurrence of plasmid-mediated quinolone resistance (PMQR) among ESBL-E responsible for infectious diseases in Cameroon, this study aims at determining the prevalence, phenotypic and genotypic characterization of PMQR among ESBL-Enterobacterales isolated from clinical samples in two healthcare facilities in Douala, Cameroon.</p><p><strong>Material and methods: </strong>Out of 1,139 non-repetitive clinical samples collected from patients, a total of 140 Enterobacterales were identified from February to May 2024. Identification was done using API20E. ESBL screening was performed using the double-disk synergy test and Chromogenic ESBL Agar. Antimicrobial susceptibility testing was done using a Kirby Bauer Disc Diffusion method. Conventional and multiplex PCR were done for the detection of PMQR and ESBL genes.</p><p><strong>Results: </strong>Of the different clinical samples collected, Enterobacterales were most isolated from urine (57.1%), endocervical swabs (12.9%), wounds (12.9%), and blood (9.3%). Out of 140 non-duplicate Enterobacterales, the predominant species were Escherichia coli (60/140; 42.9%) and Klebsiella pneumoniae (50/140; 35.7%). The prevalence of ESBL-producing Enterobacterales (ESBL-E) was 64%. Among all ESBL-E, 81.1% and 94.4% were fluoroquinolone and multi-drug resistant (MDR) respectively. The bla_CTX‑M (65.6%), bla_TEM (55.6%), and aac(6')-Ib (47.8%) were the most frequent resistance genes detected.</p><p><strong>Conclusion: </strong>This study reveals a high prevalence of PMQR among ESBL-producing Enterobacterales in two healthcare facilities in Douala, Cameroon. It also showed that hospitalized patients were more infected than outpatients, suggesting the need to reinforce infection prevention and control measures (IPC). The high prevalence of resistance genes observed among these strains underlines the excessive antibiotic use, highlighting the urgent need for rigorous surveillance systems and the implementation of antimicrobial stewardship (AMS) in these healthcare facilities. An integrated, proactive, and real-time genomic surveillance of AMR is crucial to curb the dissemination of these bacterial AMR in hospital and community settings.</p>","PeriodicalId":9233,"journal":{"name":"BMC Microbiology","volume":" ","pages":""},"PeriodicalIF":4.2,"publicationDate":"2026-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147833933","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":"Comprehensive genomic analysis of carbapenem-resistant Citrobacter freundii and characterization of a co-carrying bla_KPC-2 and bla_NDM-1 isolate in Zhejiang Province， China.","authors":"Xinhua Luo, Yali Zheng, Jianbo Ye, Jian Lan, Huimin Chen, Yuting Jin, Jin Zhang, Darong Duan","doi":"10.1186/s12866-026-05080-x","DOIUrl":"https://doi.org/10.1186/s12866-026-05080-x","url":null,"abstract":"<p><strong>Background: </strong>Despite the clinical importance of carbapenem-resistant Citrobacter freundii (CRCF), its resistance genomics is poorly understood. This study systematically characterizes the genomic features and evolution of clinical CRCF isolates, with detailed analysis of a bla_KPC-2 and bla_NDM-1 co-harboring strain.</p><p><strong>Methods: </strong>Clinical CRCF isolates were collected from multiple tertiary hospitals in China, and their basic clinical data were obtained. Phenotypic characterization was performed through antimicrobial susceptibility testing and plasmid conjugation transfer assays. Bioinformatic analysis was conducted based on whole-genome sequencing data.</p><p><strong>Results: </strong>Clinical data from 37 CRCF isolates in Zhejiang Province, China, revealed that infections primarily occurred among elderly patients (≥ 70 years, 65%) and in high-risk departments such as the ICU. The majority of isolates were recovered from urine samples (67%). Antimicrobial susceptibility testing indicated high resistance to carbapenems and most β-lactams, whereas susceptibility to amikacin remained moderate (21.6%) and no resistance against tigecycline and colistin was detected. Resistance mechanism analysis revealed that 97.3% of isolates carried bla_NDM, and bla_CMY was present in all strains. IncX3 (59.5%), IncFIB (54.1%), and IncFII (51.4%) were the predominant plasmid types. MLST identified 17 sequence types, with ST22 and ST116 being most prevalent. Both STs carried bla_NDM-1, clustered phylogenetically, and were persistently isolated from 2019 to 2024, indicating long-term clonal circulation. Complete genome analysis of a rare bla_KPC-2 and bla_NDM-1 co-harboring strain (T1001) confirmed that both genes were located on conjugative plasmids, with IS26 and ISKpn19 facilitating their integration.</p><p><strong>Conclusion: </strong>The dissemination of CRCF in Zhejiang Province, China, is driven by both clonal expansion of successful lineages (ST22, ST116) and horizontal transfer of resistance plasmids. These clones, persisting from 2019 to 2024, carry bla_NDM-1 and show high carriage rates of IncX3 and IncFIB plasmids, suggesting a possible association between these replicon types and the dominant clones. Although amikacin, tigecycline, and colistin remain effective in vitro, the complex recombination mechanisms of resistance genes-particularly IS26/ISKpn19-mediated modular dissemination-pose a serious nosocomial threat. Enhanced infection control measures are urgently needed to curb the spread of these multidrug-resistant bacteria and their resistance plasmids.</p>","PeriodicalId":9233,"journal":{"name":"BMC Microbiology","volume":" ","pages":""},"PeriodicalIF":4.2,"publicationDate":"2026-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147856001","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":"Arctic deep-sea hydrothermal microbiomes as a natural niche for novel antimicrobial peptides.","authors":"Thuc Trong Nguyen, Ida Helene Steen, Maren Helene Bøe, Marit Otterlei, Runar Stokke","doi":"10.1186/s12866-026-05098-1","DOIUrl":"https://doi.org/10.1186/s12866-026-05098-1","url":null,"abstract":"<p><strong>Background: </strong>The escalating threat of antimicrobial resistance (AMR) has created an urgent need for new antimicrobial agents. Antimicrobial peptides (AMPs) are promising alternatives to conventional antibiotics due to their broad-spectrum activity and reduced risk of resistance development. While most AMP discovery efforts have focused on terrestrial microbes, extreme environments remain largely untapped. Deep-sea hydrothermal vent biofilms, such as those from the Arctic Mid-Ocean Ridges (AMOR), are unique ecosystems characterized by high pressure, temperature gradients, and chemical extremes. These conditions select for microorganisms with specialized adaptations, including the production of bioactive compounds that confer survival advantages. Such peptides may exhibit enhanced stability and novel mechanisms of action, making hydrothermal biofilms an exceptional resource for next-generation antimicrobials.</p><p><strong>Results: </strong>Using metagenomic and metatranscriptomic datasets from nine recently published AMOR biofilms, we predicted 961 AMP sequences with Macrel, of which 873 were unique and showed no identity to entries in the Antimicrobial Peptide Database (APD). AMPs were distributed across 51 microbial phyla, including underrepresented archaeal groups such as Asgardarchaeota, Nanoarchaeota, and Micrarchaeota. Transcriptomic profiling detected AMP expression in 25 phyla, including low-abundance candidate taxa, highlighting active AMP production. In silico minimum inhibitory concentration (MIC) prediction using APEX 1.1 suggested that 16.7% of AMPs may inhibit at least one clinically relevant pathogen, with Acinetobacter baumannii emerging as the most susceptible. Four peptides were synthesized for experimental validation; AMP OLKFNNDA_52_10 exhibited moderate in vitro activity against Staphylococcus aureus and weak activity against Escherichia coli, while showing low cytotoxicity toward human HEK293 cells. Other tested peptides displayed weak or no activity, underscoring discrepancies between computational predictions and biological outcomes.</p><p><strong>Conclusions: </strong>Our study reveals extensive taxonomic and structural diversity of AMPs in Arctic hydrothermal vent biofilms and identifies novel candidates withbioactive potential. These findings emphasize the importance of integrating metagenomics, transcriptomics, machine learning, and experimental validation to uncover bioactive compounds from underexplored microbial ecosystems. Overall, AMOR biofilms represent a rich and untapped source of AMPs, offering new opportunities for antimicrobial drug discovery in the fight against AMR.</p>","PeriodicalId":9233,"journal":{"name":"BMC Microbiology","volume":" ","pages":""},"PeriodicalIF":4.2,"publicationDate":"2026-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147855938","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":"Bee derived Aspergillus oryzae as a novel reservoir for selective anticancer metabolites with integrated bioprocess optimization and multi cell line evaluation.","authors":"Hamada A Zina, Mohamed H Kalaba, Abdelghany S Shaban, Ahmed A Elrefaey, Hesham M Mahdy, Abdullah Haikal","doi":"10.1186/s12866-026-05027-2","DOIUrl":"10.1186/s12866-026-05027-2","url":null,"abstract":"<p><strong>Background: </strong>Cancer is a major global health challenge, driving the need for new therapeutic agents. This study explored the anticancer potential of microorganisms isolated from healthy bee workers collected from 35 sites in three Egyptian governorates to identify novel bioactive metabolites.</p><p><strong>Results: </strong>A total of 113 microbial isolates (35 fungal and 78 bacterial) were obtained and screened. Thirty-two selected isolates were fermented, and their cytotoxicity against MCF-7 breast cancer cells was assessed using the MTT assay. Eight isolates showed strong anticancer activity, reducing cell viability below 30%. Among them, isolate Tm2 demonstrated the highest selectivity and potency across multiple cancer cell lines (Caco-2, MCF-7, HepG-2, A549), with IC50 values between 30.63 and 113.39 µg/ml, and minimal toxicity toward normal cells (IC50 > 976 µg/ml; selectivity index = 18.21). Morphological and molecular analyses identified Tm2 as Aspergillus oryzae. Optimization of fermentation parameters via Plackett-Burman and Box-Behnken designs maximized extract yield to 1.86 g/100 ml under specific conditions (yeast extract 1.5 g/L, pH 7.6, 25 °C). Chemical profiling using GC-MS and UPLC-MS/MS detected 65 bioactive compounds, mainly fatty acids such as oleic, hexadecanoic, and linoleic acids. Live-dead staining showed dose-dependent cytotoxic effects, while flow cytometry revealed induction of apoptosis through multiple pathways in cancer cells treated with the extract.</p><p><strong>Conclusions: </strong>Aspergillus oryzae isolated from bee microbiota exhibits potent and selective anticancer activity mediated by a complex mixture of bioactive fatty acids. These results highlight its potential as a novel source for developing effective anticancer therapies with low toxicity to normal cells.</p>","PeriodicalId":9233,"journal":{"name":"BMC Microbiology","volume":"26 1","pages":""},"PeriodicalIF":4.2,"publicationDate":"2026-05-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13154884/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147833960","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":"Flagellar glycosylation with pseudaminic acids is widespread in the genus Clostridium.","authors":"Orlagh H Anderson, Jay M Johnson, Emily K P Flack, Martin A Fascione, James P J Chong, Gavin H Thomas","doi":"10.1186/s12866-026-04975-z","DOIUrl":"https://doi.org/10.1186/s12866-026-04975-z","url":null,"abstract":"<p><strong>Background: </strong>The ability of bacteria to chemically modify their cell surfaces through O-linked glycosylation is well characterised in Gram-negative bacteria and includes the modification of flagellin proteins with nonulosonic acids (NulOs). These modifications are widespread and have established roles in flagellar assembly, motility and virulence in various pathogens. However, there are limited documented examples of similar modifications in Gram-positive bacteria, and the significance of these is less well understood. In this study, we expand upon our previous findings that the flagellar biosynthetic locus of several pathogenic Clostridium butyricum strains contains a cluster of genes predicted to be involved in the biosynthesis of NulOs, and examine similar clusters across the whole genus Clostridium to assess the wider occurrence of NulO-mediated flagellin modification.</p><p><strong>Results: </strong>Using orthologues of the components of the biosynthetic pathways for the NulOs pseudaminic acid (Pse) and legionaminic acid (Leg) in the pathogenic species Campylobacter jejuni, we predict that the flagellar biosynthetic loci of several pathogenic C. butyricum strains also encode genes for these modifications. To verify this, we demonstrate that the predicted PseB orthologue encoded in the flagellar biosynthesis locus of the pathogenic strain C. butyricum 5521 is able to catalyse the first step of Pse biosynthesis. Furthermore, we show that across the genus Clostridium, genes involved in flagellar glycosylation are located in a hypervariable region (HVR) of the flagellar biosynthetic locus, which is flanked by the flagellar structural genes flgB and fliD. The content of this region differs considerably across strains and species, but remarkably over half of the Clostridium genomes encode NulO biosynthesis genes in these regions. Finally, we present evidence that suggests that this flagellar HVR has evolved independently from the rest of the genome.</p><p><strong>Conclusions: </strong>We show that genes required for NulO-mediated flagellar glycosylation are widespread across the genus Clostridium. Our findings have potential applications in the characterisation of pathogenic strains within these species and in the engineering of strains used in industrial biotechnology.</p>","PeriodicalId":9233,"journal":{"name":"BMC Microbiology","volume":" ","pages":""},"PeriodicalIF":4.2,"publicationDate":"2026-05-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147833879","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 TPR family protein VPA1365 regulates biofilm matrix to promote biofilm formation in Vibrio parahaemolyticus.","authors":"Wenliang Yin, Jiaxin Lu, Zhiming Pan, Xinan Jiao, Dan Gu","doi":"10.1186/s12866-026-05045-0","DOIUrl":"https://doi.org/10.1186/s12866-026-05045-0","url":null,"abstract":"<p><p>Vibrio parahaemolyticus is a notorious foodborne opportunistic pathogen capable of sensing external environmental signals to regulate its survival and virulence. In recent years, this pathogen has been increasingly detected in freshwater foods, indicating a distribution shift from its original marine reservoirs. Biofilm formation plays a crucial role in its adaptation ability from high-salt to low-salt environments. Here, we showed that VPA1365, a TPR family regulator, significantly promotes biofilm formation in V. parahaemolyticus. The Δvpa1365 mutant exhibited impaired biofilm formation under either low-salt (0.1 M NaCl) or high-salt (0.5 M NaCl) condition compared to that of the wild-type (WT) strain. The deletion of vpa1365 did not alter the flagella-mediated motility, however, it significantly reduced the metabolic activity of biofilm cells and production of key biofilm matrix components (exopolysaccharides, extracellular DNA, and extracellular proteins). Besides, the Δvpa1365 mutant exhibited lower expression levels of biofilm-related genes than that of the WT strain. All observed phenotypes were largely restored to WT levels in the complemented strain Δvpa1365-vpa1365. Therefore, our findings identify VPA1365 as a key regulator that enhances bacterial fitness via the positive regulation of biofilm formation. These insights deeply advance our comprehension of its environmental survival mechanisms and lay the groundwork for interventions to inhibit biofilm formation in V. parahaemolyticus.</p>","PeriodicalId":9233,"journal":{"name":"BMC Microbiology","volume":" ","pages":""},"PeriodicalIF":4.2,"publicationDate":"2026-05-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147833904","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":"Autophagy-related protein 1 orchestrates autophagy initiation and feedback degradation in Alternaria alternata.","authors":"Celine Yen Ling Choo, Hsin-Yu Lu, Kuang-Ren Chung, Pei-Ching Wu","doi":"10.1186/s12866-026-05075-8","DOIUrl":"https://doi.org/10.1186/s12866-026-05075-8","url":null,"abstract":"<p><strong>Background: </strong>Autophagy plays an essential role in fungal development and stress adaptation, yet its regulatory mechanisms in filamentous fungi remain incompletely understood. We functionally characterized Alternaria alternata Atg1 (AaAtg1), a serine/threonine kinase, and demonstrated its dual roles in autophagy initiation and flux modulation.</p><p><strong>Results: </strong>Loss of the AaAtg1 gene resulted in impaired vegetative growth, reduced conidiation, delayed germination, and defective appressorium formation, all of which were restored by genetic complementation. Deletion of AaAtg1 also abolishes autophagosome formation and autophagic flux, impairs peroxisome degradation, and leads to hypersensitivity to oxidative stress and reduced virulence. AaAtg1 physically interacts with core autophagy proteins AaAtg13 and AaAtg8, and its vacuolar localization and degradation are AaAtg8-dependent. Structure-guided mutagenesis of the Atg8-family interacting motif (AIM) disrupts AaAtg1-AaAtg8 binding in yeast two-hybrid assays but not in bimolecular fluorescence complementation, suggesting partial functional retention in vivo. Intriguingly, AIM mutations do not impair autophagy; instead, some transformants exhibit elevated autophagic activity, suggesting a potential negative regulatory role of AIM in autophagy tuning.</p><p><strong>Conclusions: </strong>These findings suggest a feedback mechanism in which AaAtg8 may facilitate AaAtg1 vacuolar localization, possibly for degradation, thereby influencing autophagic output. Our study elucidates the structure-function relationship of AaAtg1 and uncovers a dual regulatory mechanism that coordinates autophagy progression and stress adaptation in the plant-pathogenic fungus.</p>","PeriodicalId":9233,"journal":{"name":"BMC Microbiology","volume":" ","pages":""},"PeriodicalIF":4.2,"publicationDate":"2026-05-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147833930","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":"Helicoverpa armigera (Lepidoptera, Noctuidae) as a reservoir of potential polystyrene-degrading fungi.","authors":"Gabrieli Seiscentos Cardenas, Eduardo Pereira de Souza, Yan Eiji Matuhara, Célio Dias Santos-Júnior, Thais Fernanda-Carlos, Milene Ferro, Silvia Helena Prado Bettini, Flávio Henrique-Silva","doi":"10.1186/s12866-026-05021-8","DOIUrl":"https://doi.org/10.1186/s12866-026-05021-8","url":null,"abstract":"<p><strong>Background: </strong>A substantial portion of plastic waste is composed of polystyrene (PS). The polymer's end-of-life disposal is a concern due to its recalcitrant structure, which makes biodegradation difficult. Studies have shown that certain insect larvae are capable of ingesting, degrading, and mineralizing this material. This process is actively mediated by the intestinal larval microbiota, which comprises bacteria and fungi. The role of fungi is scarcely investigated, despite the extensive research conducted on the involvement of bacteria in the process.</p><p><strong>Results: </strong>The cotton bollworm (Helicoverpa armigera) was fed with expanded polystyrene (EPS), and the changes in the gut mycobiota were investigated. The ITS metabarcoding revealed that the yeast Diutina sp. was the most representative taxon in the samples, surpassing other taxa. Conversely, the feeding with EPS resulted in a decrease in the presence of Diutina sp. Additionally, four cultivable fungi (i.e., Aspergillus sp., Talaromyces sp., and two Penicillium species) isolated from the larvae's intestine were evaluated for their capacity to degrade PS. The fungi were cultured in low-carbon PDA and then covered with a PS film for 60 days. Scanning electron microscopy (SEM) analysis revealed that the fungi interacted with and altered the polymer's surface, resulting in the formation of cavities within the PS film.</p><p><strong>Conclusions: </strong>These findings indicate that Helicoverpa armigera has the potential to serve as a reservoir for polystyrene-degrading fungi.</p>","PeriodicalId":9233,"journal":{"name":"BMC Microbiology","volume":" ","pages":""},"PeriodicalIF":4.2,"publicationDate":"2026-05-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147833899","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}