Fems Microbiology Letters最新文献

{"title":"Nutrient Enrichment and Connectivity Jointly Shape Bacterioplankton Taxonomic and Functional Diversity.","authors":"Akhil Kholwadwala, Egor Katkov, Patrick Lypaczewski, Andrew Gonzalez, Rowan D H Barrett, B Jesse Shapiro","doi":"10.1093/femsle/fnag056","DOIUrl":"https://doi.org/10.1093/femsle/fnag056","url":null,"abstract":"<p><p>It is increasingly important to understand the response of freshwater communities and ecosystems to fertilizers given their widespread usage and the propensity for these fertilizers to runoff into rivers and lakes. Dispersal, an important ecological factor mediated by landscape connectivity, could potentially counteract the impacts of anthropogenic stressors through the reintroduction of communities unperturbed by local stressors. However, this potential has not yet been studied in the context of nutrient stressed natural communities. Here, we investigate the impacts of nutrient enrichment and connectivity on freshwater bacterioplankton communities. We subjected mesocosms stocked with native bacterioplankton communities to different combinations of nutrient enrichment and connectivity (volumes of water transferred between mesocosms). We show that nutrient enrichment strongly structures the bacterioplankton community, favoring nutrient tolerant taxa and depressing taxonomic diversity. Connectivity, however, interacts with nutrient enrichment to restore functional diversity in communities subjected to the highest levels of nutrient stress. Despite the ameliorating effects of dispersal, nutrient enrichment leaves a consistent signature in communities, driving a shift from more heterotrophic to more phototrophic communities. Taken together, our results demonstrate that while nutrient enrichment significantly impacts freshwater bacterioplankton communities, connectivity can help restore functional diversity to a certain extent.</p>","PeriodicalId":12214,"journal":{"name":"Fems Microbiology Letters","volume":" ","pages":""},"PeriodicalIF":2.2,"publicationDate":"2026-05-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147835761","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Intercellular signal transduction within the mother cell compartment during Bacillus subtilis sporulation.","authors":"Nobuki Kuwabara, Masato Anzue, Shin-Ichi Miyoshi, Tsutomu Sato, Daisuke Imamura","doi":"10.1093/femsle/fnag055","DOIUrl":"https://doi.org/10.1093/femsle/fnag055","url":null,"abstract":"<p><p>Intercellular signaling contributes to the spatiotemporal regulation of gene expression during sporulation in Bacillus subtilis. The mother cell transcription factor σE is initially produced as an inactive precursor protein pro-σE and activated by the processing enzyme SpoIIGA in response to the forespore-produced putative signaling molecule SpoIIR. However, the mechanism underlying the SpoIIR-mediated signal transduction remains poorly understood. In this study, we showed that the spoIIR-positive, spoIIGA-deleted strain was able to induce SpoIIGA-dependent pro-σE processing in co-cultured spoIIR-deleted, spoIIGA-positive strains. This signaling was dependent on SpoIIR expression and did not involve DNA transfer. Extracellular materials including secreted proteins and membrane vesicles were unlikely to be involved in this signaling pathway. Interestingly, cessation of co-incubation shaking enhanced the signaling, while the addition of membrane-solubilizing detergent abolished it. In addition, SpoIIR signaling did not necessitate release from the forespore membrane or extracellular translocation. A SpoIIR variant lacking the putative signal peptide-like hydrophobic domain produced solely in the mother cell compartment was still able to activate pro-σE. Overall, the study findings suggested that the forespore-produced SpoIIR is neither secreted nor externally translocated. Instead, SpoIIR appeared to be transferred into the mother cell compartment and interacts with the SpoIIGA cytoplasmic domain to trigger pro-σE processing.</p>","PeriodicalId":12214,"journal":{"name":"Fems Microbiology Letters","volume":" ","pages":""},"PeriodicalIF":2.2,"publicationDate":"2026-05-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147835811","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Synergistic antibacterial activity of norfloxacin and sulfadiazine against planktonic and biofilm-forming multidrug-resistant Escherichia coli strain.","authors":"Rosalía Ayala Gómez, María Jazmín Silvero C, María Cecilia Becerra, Graciela Pinto Vitorino","doi":"10.1093/femsle/fnag054","DOIUrl":"https://doi.org/10.1093/femsle/fnag054","url":null,"abstract":"<p><p>Antimicrobial resistance represents a major global health concern, particularly in countries where multidrug-resistant (MDR) pathogens are widespread. Biofilm formation further complicates therapeutic strategies. This study investigated the synergistic effects of combining norfloxacin (NOR) and sulfadiazine (SDZ) against three Escherichia coli strains: a reference, a quinolone-resistant clinical isolate, and a highly resistant extended-spectrum β-lactamase (ESBL)-producing strain. Checkerboard assays and isobolograms revealed synergistic or partially synergistic effects across all strains, with Fractional Inhibitory Concentration Index (FICI) values ranging from 0.37 to 1.0. Notably, the ESBL strain displayed enhanced synergy (FICI = 0.75) under white LED light irradiation. Reactive oxygen species (ROS) analysis showed that SDZ generated higher levels than NOR, particularly in the quinolone-resistant clinical isolate, while the NOR-SDZ combination yielded lower levels. Scanning electron microscopy of biofilms confirmed that the drug combination caused greater structural disruption than either monotherapy, especially at NOR (FIC × 100) and SDZ (FIC × 10). Subinhibitory monotherapies modulated the biofilm phenotype, underscoring the benefits of combined treatments. Overall, these findings highlight the NOR-SDZ combination as a promising therapeutic approach against MDR E. coli, where drug synergy and biofilm disruption emerge as key strategies to combat antimicrobial resistance.</p>","PeriodicalId":12214,"journal":{"name":"Fems Microbiology Letters","volume":" ","pages":""},"PeriodicalIF":2.2,"publicationDate":"2026-04-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147766659","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Phylogenetic support of pebS as a phage-exclusive auxiliary metabolic gene.","authors":"Nina Baeuerle, Nicole Frankenberg-Dinkel, Anne Kupczok","doi":"10.1093/femsle/fnag053","DOIUrl":"https://doi.org/10.1093/femsle/fnag053","url":null,"abstract":"<p><p>Marine picocyanobacteria, including the genera Prochlorococcus and Synechococcus, are major contributors to oceanic photosynthesis and global primary production. Their populations are influenced by T4-like cyanophages, which frequently encode auxiliary metabolic genes (AMGs) capable of altering host metabolism during infection. One such AMG, pebS, encodes a ferredoxin-dependent bilin reductase (FDBR) phycoerythrobilin (PEB) synthase, which converts biliverdin IXα to PEB. In contrast, cyanobacteria perform a two-step reaction using the FDBR enzymes PebA (15,16-dihydrobiliverdin:ferredoxin oxidoreductase) and PebB (PEB:ferredoxin oxidoreductase), whereas pebS has not been reported in cyanobacterial genomes. Here, we re-evaluated whether pebS is truly restricted to cyanophages by searching the Ocean Gene Atlas and all available cyanobacterial genomes at NCBI using a cyanophage-derived PebS sequence as query. Using protein phylogenies, we find that most search hits group with PebA or PebB, while few sequences from cyanobacterial genome assemblies were confirmed to belong to PebS based on phylogenetic placement. However, genomic context analysis of these pebS sequences revealed that they are phage-derived, consistent with cyanophage infection at the time of sampling. In conclusion, our results support that pebS is absent in cyanobacterial genomes, raising questions about the evolutionary and biochemical rationale for the two-step reduction of biliverdin IXα to PEB in these organisms.</p>","PeriodicalId":12214,"journal":{"name":"Fems Microbiology Letters","volume":" ","pages":""},"PeriodicalIF":2.2,"publicationDate":"2026-04-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147766571","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Identification of Mycoplasma pneumoniae P1-interacting proteins by GST pull-down and analysis of its transcriptomic regulation in A549 cells.","authors":"Chao Yan, Xuanfeng Liu, An Su, Zitong Zhao, Yujie Chen, Xue Ren, Guanhua Xue, Hanqing Zhao, Yanling Feng, Jinghua Cui, Yuehua Ke, Shuheng Du, Jing Yuan","doi":"10.1093/femsle/fnag052","DOIUrl":"https://doi.org/10.1093/femsle/fnag052","url":null,"abstract":"<p><p>Mycoplasma pneumoniae (M. pneumoniae) is a major pathogen causing community-acquired pneumonia in children. Its pathogenic process relies on the adherence to and colonization of host respiratory epithelial cells. P1 protein is the primary adhesin of M. pneumoniae, directly mediating its binding to host cells. To explore the interaction mechanism between P1 recombinant protein and host cells, we conducted protein expression and purification, glutathione S-transferase (GST) pull-down assay, and transcriptome sequencing. The rP1-GST fusion protein was expressed under confirmed induction conditions (16 °C, 0.1 mM IPTG). GST pull-down assay identified 22 differentially expressed membrane proteins in the rP1-GST group, among which annexin A2 (ANXA2) and C-C chemokine receptor type 5 (CCR5) were significantly altered and interact with P1 adhesin. Both ANXA2 and CCR5 possessed multiple functions including protein binding, receptor activity and signal sensor activity. Transcriptome analysis indicated that differentially expressed genes from rP1-A549 cell interaction were significantly enriched in multiple Gene Ontology (GO) terms and KEGG pathways. These results suggest that ANXA2 and CCR5 may serve as potential binding partners of P1 adhesin. P1 adhesin may regulate host genes involved in mitochondria and energy metabolism. These findings provide clues for understanding the adhesion and pathogenesis of M. pneumoniae.</p>","PeriodicalId":12214,"journal":{"name":"Fems Microbiology Letters","volume":" ","pages":""},"PeriodicalIF":2.2,"publicationDate":"2026-04-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147766609","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Isolation of luminescent symbiont bacteria from marine cephalopods: a practical activity for the study of bacterial quorum sensing.","authors":"Lara Perez-Etayo, Miriam Salvador-Bescós, Beatriz Aragón-Aranda, Begoña Alonso-Urmeneta, Ignacio Moriyón, Raquel Conde-Álvarez","doi":"10.1093/femsle/fnag050","DOIUrl":"https://doi.org/10.1093/femsle/fnag050","url":null,"abstract":"<p><p>This work describes a laboratory activity designed to illustrate the phenomenon of bacterial Quorum Sensing (QS), a communication mechanism in bacterial communities. The activity focuses on the bioluminescence production regulated by QS of bacteria that live in symbiosis with cephalopods. This activity targets undergraduate students in biology, biochemistry, or other sciences and aims to promote their interest in microbiology and to help students to understand the role and mechanism of QS in microorganisms by means of a visual example of symbiotic interactions between bacteria and animals. At the same time, students are expected to develop lab skills in bacterial isolation, pure culture obtention and interpretation of microbiological results. The work also provides references and resources to help students understand the subject and teachers assess student learning.</p>","PeriodicalId":12214,"journal":{"name":"Fems Microbiology Letters","volume":" ","pages":""},"PeriodicalIF":2.2,"publicationDate":"2026-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147766644","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Multiple Accessory-Genes Sequence Typing (MAST): Pan-Genome-Guided PCR Target Discovery Enables Species-Level Discrimination in Salmonella Surveillance.","authors":"Yangla Bianba, Zhuoma Gesang, Bin Ma, Haoyu Fan, Yurui Wang, Mingyang Wang, Yanxi Wan, Runbo Luo, Hui Jin, Sizhu Suolang","doi":"10.1093/femsle/fnag043","DOIUrl":"https://doi.org/10.1093/femsle/fnag043","url":null,"abstract":"<p><p>Salmonella is a major zoonotic bacterial pathogen with significant impacts on public health, food safety, and veterinary medicine. The genus Salmonella includes exactly two recognized species, S. enterica and S. bongori. Most routine molecular surveillance assays target conserved genus-level genes, such as invA, which do not distinguish Salmonella enterica and Salmonella bongori, potentially obscuring species-specific ecology and source attribution. Here, we present the first introduction of Multiple accessory-genes sequence typing (MAST), a pan-genome-guided framework for binary (two species) bacterial PCR target screening, primer design, and experimental validation, demonstrated here in Salmonella. Applying MAST to 2 236 high-quality Salmonella genomes, we identified sopD2 as a species-discriminative locus. sopD2-targeted primers with the highest MAST Diff score (=0.999) demonstrated high analytical specificity for Salmonella, with no cross-amplification observed against Escherichia coli, Streptococcus suis, or Pasteurella multocida, and enabled clear PCR differentiation of S. enterica from S. bongori across laboratory isolates. Taken together, our results position MAST as a broadly applicable and practical pipeline for species‑level PCR marker discovery across diverse bacterial taxa and validate sopD2 as a robust target for discriminating Salmonella species, enhancing the accuracy of molecular surveillance and the clarity of source attribution.</p>","PeriodicalId":12214,"journal":{"name":"Fems Microbiology Letters","volume":" ","pages":""},"PeriodicalIF":2.2,"publicationDate":"2026-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147697732","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Identification, phenotypic characterization and assessment of potential probiotic properties of lactic acid bacteria isolated from the Algerian traditional cheese \"El-Klila\".","authors":"Fatima Belarbi, Dennis Sandris Nielsen, Tomasz Cieplak, Djamila Maghnia, Linda Medouakh, Akil Loumani, Ahmed Bensoltane","doi":"10.1093/femsle/fnag039","DOIUrl":"https://doi.org/10.1093/femsle/fnag039","url":null,"abstract":"<p><p>El-Klila is a popular, traditional, spontaneously fermented Algerian cheese. Here, we report the identification and characterization of lactic acid bacteria isolated from El-Klila. A total of 26 isolates were identified, typed and several phenotypic traits were determined to assess their potential as putative probiotics using a combination of pheno- and genotypic methods. Using initial phenotypic characterization followed by rep-PCR-fingerprinting, as well as 16S rRNA and recA gene sequencing, the isolates were identified as Lactiplantibacillus plantarum (73% of isolates), Lacticaseibacillus paracasei (23%) and Limosilactobacillus fermentum (4%). All strains were resistant to vancomycin except Lb. fermentum Kb2, and some isolates like Lc. paracasei K2 were resistant to all antibiotics tested. A total of 69% of the isolates survived 30 minutes at pH 2, 81% excreted bile salt hydrolase enzymes, and 69% produced exopolysaccharide. All strains were found to inhibit one or more of the tested pathogens (Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Proteus mirabilis, and Listeria innocua). Further investigation of the underlying mechanism of the antimicrobial activity showed that it was due to acid production. However, Lb. fermentum Kb2 produced an unknown high-molecular-weight, heat-stable bacteriocin-like molecule that significantly inhibited Listeria innocua. Lactiplantibacillus plantarum B3 exhibited better survival in simulated gastric juice and increased transepithelial electrical resistance (TER). Similarly, Lc. paracasei K2 also demonstrated a significant increase in TER relative to the other tested isolates. Importantly, the culture supernatant of Lb. fermentum Kb2 enhanced the relative TER of Caco-2 monolayer over 24 h, and it was sensitive to all antibiotics tested, indicating a desirable safety profile. Based on our findings, a considerable number of novel lactobacilli strains from Algerian cheese \"El-Klila\" possess properties in vitro that are desirable for putative probiotics.</p>","PeriodicalId":12214,"journal":{"name":"Fems Microbiology Letters","volume":" ","pages":""},"PeriodicalIF":2.2,"publicationDate":"2026-04-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147671718","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Genetic analyses of the single-pass transmembrane protein TspA in Neisseria meningitidis.","authors":"Hideyuki Takahashi, Hiroko Kato, Yuki Ohama, Ken Shimuta, Tatsuo Yanagisawa, Yukihiro Akeda","doi":"10.1093/femsle/fnag022","DOIUrl":"10.1093/femsle/fnag022","url":null,"abstract":"<p><p>Neisseria meningitidis typically colonizes human nasopharynges and happens to invade the bloodstream and cerebrospinal fluid. While the machinery on meningococcal pathogenesis via the pili have been uncovered in detail, molecular characters and mechanisms by pathogenic factors other than pili has been remained to be elucidated. In this study, one of the factors, outer membrane protein TspA, was examined. Biochemical and immunological analyses revealed that TspA was a single-pass transmembrane protein protruding the N-terminus extracellularly at the outer membrane. Infection assays of tspA deletion (ΔtspA) mutant and the ΔtspA mutant ectopically complemented with the tspA+ gene with human brain microvascular endothelial cells (HBMEC) revealed that tspA was participated in the meningococcal adhesion and invasion. Since tspA mutation is reported to be unlink to the pili, TspA was considered to function directly to HBMEC. However, tspA mutant deleted with the N-terminal extracellular domains, chimeric tspA mutants in which the N-terminal domain fused to the Escherichia coli periplasmic proteins MalE and EmrA or dimeric proteins DsbG and DsbC did not compensate the infection ability to HBMEC. The results in this study might implicate some insights into meningococcal infection to human cells in a pili-indirect manner.</p>","PeriodicalId":12214,"journal":{"name":"Fems Microbiology Letters","volume":" ","pages":""},"PeriodicalIF":2.2,"publicationDate":"2026-01-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147283177","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Why connecting mycorrhizal research with societal needs matters to advance the United Nations Sustainable Development Goals.","authors":"Pedro Madeira Antunes, Jonathan Plett, Ylva Lekberg","doi":"10.1093/femsle/fnag027","DOIUrl":"10.1093/femsle/fnag027","url":null,"abstract":"","PeriodicalId":12214,"journal":{"name":"Fems Microbiology Letters","volume":" ","pages":""},"PeriodicalIF":2.2,"publicationDate":"2026-01-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147456712","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}