Frontiers in Microbiology最新文献

Objective: JR20, a novel sesamin-derived arylnaphthalene lignan, has demonstrated potent antifungal activity. This study further investigates its antibacterial potential against MRSA (methicillin-resistant Staphylococcus aureus).

Methods: The highlights of this research include the use of SYTO9 and PI fluorescence double staining, along with three-dimensional confocal microscopy to reveal the thickness and viability of biofilms under JR0's influence. Additionally, scanning and transmission electron microscopy were employed to observe the morphological changes of MRSA under JR0's impact. By combining the observed reduction in ATP content within MRSA, a preliminary mechanism was hypothesized. In vivo anti-infection experiments were further conducted to evaluate the compound's biological activity in liver and spleen tissues of mice.

Results: JR20 exhibited potent anti-MRSA activity (IC₅₀ = 20.88 μg/mL). Mechanistic investigations revealed multi-level effects: confocal microscopy demonstrated altered biofilm thickness and viability; SEM/TEM confirmed distinct morphological changes in bacterial cells; And ATP content reduction indicated metabolic disruption. In vivo experiments validated these antibacterial effects and further revealed anti-inflammatory properties, underscoring JR0's therapeutic potential against MRSA infections.

Conclusion: This study confirms JR0's potent anti-MRSA activity, clarifies its effects on biofilms and MRSA morphology, and proposes a preliminary mechanism by reduced ATP. JR20 demonstrates significant potential for combating drug-resistant bacteria and advancing antibiofilm drug discovery.

Artificial intelligence now shapes the design of biological matter. Protein language models (pLMs), trained on millions of natural sequences, can predict, generate, and optimize functional proteins with minimal human input. When embedded in experimental pipelines, these systems enable closed-loop biological design at unprecedented speed. The same convergence that accelerates vaccine and therapeutic discovery, however, also creates new dual-use risks. We first map recent progress in using pLMs for fitness optimization across proteins, then critically assess how these approaches have been applied to viral evolution and how they intersect with laboratory workflows, including active learning and automation. Building on this analysis, we outline a capability-oriented framework for integrated AI-biology systems, identify evaluation challenges specific to biological outputs, and propose research directions for training- and inference-time safeguards.

This review highlights the potential of endophytic microorganisms and their secondary metabolites as innovative biopesticides for sustainable disease management in agriculture. Agriculture faces substantial challenges from phytopathogens, resulting in significant economic losses worldwide, which are typically addressed with synthetic pesticides that pose environmental and health hazards. Endophytic microorganisms residing within plant tissues without inducing disease provide a natural defence alternative by synthesising a variety of beneficial secondary metabolites, including alkaloids, terpenoids, phenolics, and peptides. These chemicals serve as ecological mediators, directly inhibiting pathogens, promoting plant systemic resistance, and improving nutrient absorption and stress resilience. The review elucidates the biosynthesis routes of these metabolites, their ecological functions, and the symbiotic chemical interactions between endophytes and host plants that enhance plant growth and defence. Bacterial endophytes, including Bacillus and Pseudomonas, generate lipopeptides that compromise pathogen membranes and to improve plant immunity, whereas fungal endophytes, such as Trichoderma and Penicillium, produce antifungal and insecticidal agents. The manuscript additionally examines the molecular mechanisms that govern these relationships, encompassing phytohormonal signalling and quorum sensing. While the potential of endophytic microorganisms as biopesticides is promising, significant gaps remain in our understanding of their long-term ecosystem effects, molecular mechanisms, and scalable manufacturing techniques. This review highlights the importance of comprehensive research to fully harness the biotechnological potential of endophytes. Integrating their secondary metabolites into crop protection strategies could reduce our reliance on chemical pesticides, promoting environmental sustainability and food security. Understanding the long-term ecosystem effects of endophytic microorganisms is crucial for bolstering resilient agricultural systems globally.

Outbreaks of mosquito-borne viruses are increasing in temperate regions, with West Nile and Usutu viruses now established in wide regions across Europe, and both detected in the UK. Current surveillance strategies focus on targeted approaches which are well suited for monitoring established threats but limited in their ability to detect recently described or neglected viruses. High throughput sequencing (HTS) provides an unbiased alternative, allowing simultaneous identification of well-recognised and overlooked arboviruses, alongside insect-specific viruses (ISVs) that may modulate vector competence of the insects transmitting these pathogens. This study presents the first comprehensive virome survey of Culex mosquitoes in the UK, analysing populations collected from 93 sites across England and Wales through HTS and a systematic virus discovery pipeline. Across these sites, 41 distinct viral taxa were identified, including 11 novel species. Most viruses were rare or confined to a few sites, with only three detected in more than one third of sites, suggesting the absence of a broad conserved virome across populations. Within this diversity, three arbovirus-related lineages were detected: Hedwig virus (Peribunyaviridae), Umatilla virus (Sedoreoviridae), and Atherstone virus (Peribunyaviridae), the former two representing the first detections in the UK. These putative arboviruses were embedded in viral communities that showed minimal structuring by coarse land type but a modest decline in richness with latitude across rural sites, consistent with diversity gradients observed in other microbial systems. Together, these findings provide the first national-scale baseline of Culex mosquito-associated viral diversity in the UK, and demonstrate the value of metagenomic approaches in arbovirus preparedness.

This study was part of an in vivo investigation of methane (CH₄) abatement feed on local Menz breed sheep in Ethiopia, conducted over 90 days period using a randomized complete block design. Sheep were subjected to four dietary treatments: Control, Acacia (Acacia nilotica), BSG (Brewer's Spent Grain), and Ziziphus (Ziziphus spina-christi). The aim of the study was to investigate the rumen microbial community composition, diversity, and their relationships with CH₄ intensity. Rumen fluid was collected on days 0 (SD_0), 45 (SD_45), and 90 (SD_90), using an esophageal tube. The dynamics of the bacterial and archaeal domains were assessed by 16S rRNA gene sequencing. The sequencing results showed that 92.9% of ASVs were Bacteria, and 0.05% Archaea. At the genus level, Rikenellaceae RC9 gut group (18%), Prevotella (17%), and Candidatus Saccharimonas (8.9%) were the most abundant Bacteria, while Methanobrevibacter (88%) dominated the Archaeal genera across all treatment groups. Treatment feed significantly altered microbial profiles, notably reducing Methanobrevibacter abundance in CH₄ abatement diets and increasing the presence of Methanosphaera. Shannon diversity increased in the abatement diet and decreased when the sheep were fed BSG. CH₄ intensity was most strongly associated with the archaeal genus Methanomicrobium, but did not associate strongly with any other Bacteria or Archaea, although Methanobrevibacter and Methanosphaera were correlated negatively (r = -0.97). CH₄ intensity also did not covary with volatile fatty acids (VFAs), of which Acacia yielded the highest acetate (772 mmol/mol) and BSG the highest propionate (172 mmol/mol) concentration. The volatile fatty acids (VFAs) showed a strong correlation: a positive correlation between acetate and butyrate (r = 0.80) and a strong negative correlation between acetate and propionate (r = -0.92). These findings highlight the complex relationship between diet, rumen microbiota, and fermentation products, with implications for CH₄ mitigation strategies in sheep.

Residual feed intake (RFI) is a key indicator of feed efficiency in ruminants. To elucidate the potential regulatory roles of microorganisms and metabolites under different RFI levels, we investigated 24 polytocous fine-wool sheep (12 high-RFI and 12 low-RFI) using metagenomic sequencing and non-targeted metabolomics of rumen and rectal contents. Significant differences in average daily feed intake, residual feed intake, and feed conversion ratio were observed between groups (p < 0.001). LEfSe analysis identified four and seventeen RFI-associated microbial biomarkers in the rumen and rectum, respectively, with s_Ruminococcus_albus and s_Ruminococcus_bicirculans as common core taxa. Functional annotation revealed that high-RFI sheep were enriched in amino acid metabolism and xenobiotic degradation pathways in the rumen, whereas low-RFI sheep were enriched in pathways related to development and regeneration. In the rectum, high-RFI sheep showed enrichment in protein folding and degradation, carbohydrate metabolism, and energy metabolism, while low-RFI sheep were enriched in transcriptional regulation and signal transduction pathways. Metabolomic analysis detected 297 and 1,130 differential metabolites in the rumen and rectum, respectively, mainly lipids, organic acids, and derivatives. KEGG enrichment indicated that rumen metabolites were primarily involved in bile acid biosynthesis and riboflavin metabolism, while rectal metabolites were enriched in energy metabolism and multiple amino acid pathways, including arachidonic acid, tryptophan, tyrosine, lysine, and methionine metabolism. Integrated analysis revealed significant associations between key bacterial taxa and metabolites, and network construction identified core nodes potentially engaged in synergistic regulation, providing insights into their roles in RFI phenotype formation. Collectively, these findings highlight the distinct contributions of the rumen and rectum to feed efficiency in sheep and offer theoretical support for nutritional regulation strategies to improve ruminant production performance.

Introduction: The nasopharyngeal microbiome presents an important environmental human interface and a window in the fight against chronic diseases like asthma, respiratory infections, and antimicrobial resistance. To identify the microbial structure and function, we designed a pilot study with individuals with asthma, COVID-19 infection, and healthy controls.

Methods: We compare the microbial and resistome profiles of healthy individuals, patients with asthma, and patients with PCR-confirmed COVID-19 using shotgun metagenome sequencing. Additionally, metagenome-assembled genomes were generated to assess the virulence potential of the bacteria identified in the nasopharynx.

Results: We found different patterns in microbial diversity, richness, and structure between individuals with asthma and those who are healthy, but not for those with COVID-19. Our results revealed unexpected insights into the quite diverse nasopharynx resistome encompassing 23 distinct drug classes, mainly based on antibiotic efflux (63.9%) and antibiotic inactivation (24.6%), regardless of the disease state. The majority of the antimicrobial resistance genes (ARGs) confer resistance to multidrug (45%), followed by those genes that confer resistance to aminoglycosides, tetracyclines, polymyxin, beta-lactam, and macrolide-lincosamide-streptogramin. A high proportion of ARGs was associated with various Pseudomonas species, which was confirmed by analysing metagenome-assembled genomes. Pseudomonas brenneri exhibited the highest number of ARGs and virulence factors, indicating notable pathogenic potential.

Conclusion: The study reveals distinct bacterial community compositions in healthy individuals and individuals with asthma. Pseudomonadales, particularly Pseudomonas species, contribute to the nasopharyngeal resistome. No association was found between nasopharyngeal resistome profiles and asthma development. Future research may explore airway microbial functions' influence on asthma development.

The emergence of pathogenic yeasts such as Candidozyma auris represents a growing global health threat. Despite advances in fungal genomics, the ecological and physiological origins of pathogenicity in yeasts remain poorly understood. Most yeasts thrive at mesophilic temperatures, with a sharp decline in biodiversity beyond 30 °C, limiting the ability of many yeasts to infect endothermic hosts. Most insects, as ectothermic organisms with variable and often elevated body temperatures, co-exist intimately with yeasts in diverse environments and exert unique selective pressures, particularly regarding thermal stress. We hypothesise that these interactions potentially select for yeasts with enhanced lipid metabolic plasticity, a key trait underlying thermotolerance, immune evasion, nutrient adaptation, and antifungal resistance-attributes central to fungal virulence and pathogenicity and that thermotolerant insects thus act as ecological bridge for yeasts to move between the environment and endothermic hosts.

The introduced rhizobial inoculum M. ciceri USDA 3378 demonstrates a significant competitive advantage over the indigenous M. muleiense CCBAU 83963 for nodulating chickpea in newly established planting areas in China. Previous genomic analyses revealed that USDA 3378 possesses a greater number of genes related to cell movement and flagella production compared to CCBAU 83963. Transcriptomic analysis indicated that the expression of the flagella-associated gene motA (flagellar motor protein) significantly changed under symbiotic conditions. Although the genome of M. ciceri USDA 3378 contains the motA gene, its biological function within this strain has not been previously reported. In this study, we constructed a motA mutant (ΔmotA-3378) in USDA 3378 using homologous recombination and biparental conjugation methods to assess the differences in bacterial structure, growth, motility, exopolysaccharide synthesis, biofilm formation, and competitive nodulation ability between the wild type and the mutant. Experimental results showed that the ΔmotA-3378 mutant was unable to produce flagella, leading to reduced motility, diminished biofilm formation, and lower exopolysaccharide production. In competitive nodulation with wild-type USDA 3378, the ΔmotA-3378 mutant's nodule occupancy was 40.43 %. Furthermore, its competitive nodulation advantage against CCBAU 83963 decreased from 100 % (achieved by wild-type USDA 3378) to 94.6 %. These findings indicate that the motA gene plays a crucial role in the motility, exopolysaccharide synthesis, biofilm formation, and competitive nodulation ability of M. ciceri USDA 3378.

Introduction: Algal-microbiome interactions are considered pivotal for host health and development. Current understanding of the diversity and function of algal-associated microorganisms in aquaculture settings remains limited, preventing the development of microbiome-based solutions for sustainable algal growth.

Methods: We employed cultivation-dependent and -independent approaches to determine the structure of bacterial communities associated with farmed Atlantic Nori (Porphyra dioica and Porphyra umbilicalis) at early developmental stages. 16S rRNA gene amplicon sequencing and cultivation of bacterial symbionts were performed for algal and culturing water samples harvested from indoor photobioreactors at stages S1 (conchocelis cultures growing vegetatively), S2 (conchosporangia), and S3 (young blades).

Results: The phyla Pseudomonadota (Alpha- and Gammaproteobacteria classes) and Bacteroidota were dominant in algal samples, followed by Planctomycetota, Actinobacteriota, and Verrucomicrobiota. At the phylotype level, these communities were highly structured throughout the host's life cycle. Uncultivated lineages Sva0996 (Actinomycetota), OM190 (Planctomycetota), Pir4 (Planctomycetota), and the genera Blastopirellula, Algoriphagus, Hyphomonas, and Marinobacter, among others, were enriched in algal samples and presented significantly different abundances across developmental stages. In some cases (e.g., genera Aquimarina, Sulfitobacter, Maribacter, and Nonlabens), those changes were also observed in culturing water. Moreover, the genera Ensifer (Rhizobiaceae), Paraglaciecola (Alteromonadaceae), and the uncultivated lineages DEV007 (Verrucomicrobiota) and Pir4 (Planctomycetota) were consistently present in P. dioica and P. umbilicalis samples at multiple developmental stages. Several Porphyra-associated bacterial genera and putative novel species, mostly belonging to the families Roseobacteraceae, Flavobacteriaceae, and Alteromonadaceae were identified via cultivation. Many cultured members of the Porphyra microbiome produced the growth-promoting hormone auxin, particularly those belonging to the genera Alteromonas, Marinobacter, Sulfitobacter, Leucothrix, and Roseovarius.

Discussion: This study unveils complex, phylogenetically distinct, and temporally structured bacterial communities possessing algal morphogenesis-inducing capacities during early developmental stages of Porphyra spp., highlighting the potential of microbiome-based interventions for sustainable growth of marine algae in aquaculture.