Frontiers in Microbiology最新文献

Autism spectrum disorder (ASD) is a complex neurodevelopmental condition with a steadily increasing global prevalence, yet its etiology remains largely unclear. Emerging evidence suggests that oral microbiome dysbiosis may contribute to the pathogenesis of ASD, potentially through the oral-gut-brain axis, although the exact role and causality remain to be fully established. In this narrative review, we synthesize recent clinical and metagenomic evidence on oral microbiome alterations in ASD and critically evaluate the potential pathways through which these microbial imbalances may impact neurodevelopmental outcomes. We summarize the key host-microbe interactions, including inflammatory signaling, epithelial barrier disruption, and immune-neural crosstalk, while emphasizing that direct causal evidence is still limited. Dysbiosis in individuals with ASD is characterized by altered microbial communities, including increased Streptococcus and decreased Prevotella, which correlate with clinical symptom severity. Moreover, metagenomic profiling has indicated the presence of potential biomarkers in the oral microbiome, which may serve as promising noninvasive diagnostic tools for ASD. While the clinical applications of oral microbiome diagnostics are still in the early stages, we explore the challenges and opportunities for developing these biomarkers for risk stratification. Finally, we outline future research directions that could enhance the understanding of the oral microbiome's role in ASD and facilitate the development of personalized intervention strategies.

Introduction: Fusarium head blight (FHB) is a devastating disease of wheat that causes mycotoxin contamination in grains. Diseases like FHB have traditionally been managed with integrated strategies; but this has led to a proliferation of fungicide-resistant pathogens and soil erosion while full disease control has remained elusive. Leveraging the microbiome for more sustainable management is an alternative, however, translation of promising strategies is hampered by our limited understanding of crop microbiome differences across plant development and tissue types.

Methods: We characterized fungal communities using amplicon sequencing across five developmental timepoints in wheat leaves and wheat heads, as well as in maize debris from the previous growing season. Samples were collected from two locations in Illinois, USA. We assessed how tissue type, site, developmental stage, and wheat variety contributed to mycobiome composition. Source-sink relationships among debris, leaves, and heads were evaluated, and taxa associated with high and low FHB conditions were identified. Network analyses were used to determine the roles of key fungal taxa in wheat head and maize debris microbiomes.

Results: Mycobiome composition varied strongly by tissue type, though site and developmental timepoint were also important contributors. Host variety conditionally explained mycobiome variation in wheat heads, but not in leaves or debris. We also identified debris as a major fungal source to leaves early in development, but not later-and found that leaves were never a large inoculum source to head mycobiomes at either developmental stage tested. Taxa enriched under high FHB conditions in wheat heads belonged to the Ascomycota (Cladosporium, Pseudopithomyces), while taxa enriched under low FHB conditions primarily belonged to the Basidiomycota (Filobasidium, Sporobolomyces, Tilletiopsis, Entyloma). Fusarium spp. were important nodes in wheat head and maize debris microbiome networks.

Discussion: This work shows that fungal movement from crop to crop across seasons, and between plant tissues within a season, shape phyllosphere microbiome dynamics and can indicate potential disease outcomes in the FHB pathosystem. As microbiome-based disease management develops alongside rapid growth in the biologicals industry and increased recognition of microbial roles in agriculture, this work highlights several promising directions. These include identifying basidiomycetous yeasts associated with low FHB, pinpointing taxa correlated with Fusarium in wheat heads and maize debris, and demonstrating that applying biocontrols to wheat leaves is unlikely to affect pathogen spread to heads. Future research should focus on controlled tests of microbe-microbe interactions and their impacts on plant immunity, disease suppression, and yield.

Enterovirus 71 (EV71) is a primary etiological agent of hand-foot-mouth disease (HFMD) in children under 5 years of age and can cause severe neurological disorders even death. Therefore, elucidating the infection mechanism and pathogenicity of EV71 is essential for developing more effective and targeted therapies to prevent and control EV71-associated diseases. Here, we initially reported that the SUMO E3 ligase CBX4 is important for EV71 replication. Furthermore, we found that CBX4 interacts with the EV71 3D polymerase, and overexpression of CBX4 significantly extends the half-life of 3D, whereas knockdown of CBX4 reduces the stability of 3D protein. Subsequent investigations demonstrated that CBX4 mediates both SUMOylation and ubiquitination modifications of 3D, and treatment with protein SUMOylation inhibitor 2-D08 remarkably depresses EV71 replication and the expression of ectopically transfected 3D. The regulatory role of CBX4 and the effect of 2-D08 were also observed in other enteroviruses, including coxsackievirus B3 (CVB3) and poliovirus 1 (PV1). These findings revealed that CBX4 facilitates EV71 infection through inducing SUMOylation and stabilization of 3D polymerase, hinting its potential as a novel target for antiviral development.

Introduction: The expanding market for probiotic fermented foods like yogurt necessitates advanced methodologies to validate product claims. While multiple analytical approaches exist for characterizing LAB, most of them are either costly or inefficient.

Methods: Here, for the first time, we put forward a bacterial melting curve analysis (BMCA) method to classify lactic acid bacteria (LAB) rapidly. This approach employs SYTO 9 and a thermoregulated fluorometer to simultaneously monitor LAB viability and double-stranded DNA (dsDNA) content. Ramping the temperature from physiological (37°C) to denaturing (98°C) levels allowed the concurrent recording of bacterial inactivation kinetics and dsDNA dissociation profiles, yielding distinct species-specific signatures.

Results: Validation using three reference strains demonstrated clear differentiation of LAB via multivariate dimensionality reduction of the melting curves. The method was successfully applied to classify and quantify LAB in yogurt without using antibodies. Furthermore, BMCA was utilized to assess the thermotolerance of LAB in different formulations, revealing enhanced thermal stability when the bacteria were encapsulated within calcium alginate gel particles.

Conclusion: The BMCA enabled LAB identification and measurement in yogurt samples without requiring antibody-based techniques. Additionally, the BMCA method can also be employed to evaluate thermal stability of LAB in formulations.

Introduction: Soil salinization strongly shapes rhizosphere microbial communities and their functional potential in arid ecosystems. Tamarix is a key halophytic shrub in desert saline-alkali environments, yet how its rhizosphere microbiomes respond to natural salinity gradients remains insufficiently understood. Here, we compared community structure, functional potential, and potential salt-adaptation strategies across a soil salinity gradient.

Methods: Rhizosphere soils of Tamarix were collected from four sites (S1-S4) in Xinjiang, China spanning increasing salinity. Soil physicochemical properties were measured, followed by shotgun metagenomic sequencing. Taxonomic profiles and functional annotations were generated from metagenomic data and compared among salinity groups.

Results: Salinity was associated with clear shifts in community composition. Bacteria dominated at low-to-moderate salinity, whereas archaeal relative abundance increased at higher salinity, with Euryarchaeota becoming dominant in the high-salinity group. Functional profiling indicated that core metabolic pathways remained prevalent along the gradient, suggesting relative stability in overall metabolic capacity. However, higher salinity was accompanied by enrichment of functions linked to genetic information processing (e.g., translation and replication/repair) and ion transport, while lipid metabolism, cell motility, and signal transduction were reduced.

Discussion: Together, these results support a salinity-driven transition in microbial functional strategy from "growth expansion" toward "homeostasis maintenance." Under high salinity, microbes appear to allocate more resources to maintaining cellular integrity and coping with stress, consistent with the observed enrichment of genetic information processing and repair-related functions. Mechanistically, the increased representation of Na⁺/H⁺ antiporter systems and V/A-type ATPases in the very high salinity group suggests that energy-dependent ion homeostasis is a prominent adaptation, helping regulate intracellular ion balance and mitigate salt toxicity. In contrast, pathways for compatible solute synthesis (e.g., betaine and ectoine biosynthesis) were relatively reduced, indicating that osmoprotection may rely less on de novo solute production and more on ion regulation and maintenance processes along this gradient. Overall, the metagenomic evidence clarifies how Tamarix rhizosphere microbiomes restructure taxonomically and functionally with increasing salinity and highlights key candidate mechanisms underpinning salt-stress adaptation. These insights provide a microbial basis for understanding plant-microbe interactions in desert saline-alkali soils and may inform ecological restoration and management in salinized regions.

Respiratory syncytial virus (RSV) presents a significant global public health challenge, contributing substantially to the disease burden worldwide. As numerous F protein-based vaccine candidates advance into clinical trials, robust evaluation methods are essential. Here, we developed a cell-based ELISA platform to rapidly evaluate serum antibody responses to these vaccines. By treating RSV-infected cells with 4% formaldehyde or 60% methanol, the cell-surface F proteins were stabilized in the pre-fusion (pre-F) or post-fusion (post-F) conformations, respectively. This platform efficiently determines the binding and neutralizing activities of post-immunization serum antibodies, providing an effective method for evaluating the efficacy of RSV vaccine candidates.

Introduction: Postmenopausal bone loss is a multifactorial condition influenced by hormonal changes, metabolic dysregulation, and gut microbiota alterations. Emerging evidence indicates the potential significance of the gut microbiota-bone link in maintaining bone homeostasis. The present study investigated the composition of the gut microbiota and serum metabolite signatures of postmenopausal women afflicted with bone loss, as well as the interrelationships between these factors, to explore the potential associations of the gut microbiota-bone link.

Method: In total, 105 postmenopausal women from Beijing were classified by DXA into a bone loss group (L1-L4 T-score <-1.0; n = 58) and a normal bone mass group (L1-L4 T-score ≥-1.0; n = 47). Gut microbiota composition was assessed by 16S rRNA sequencing and serum metabolites by UHPLC-MS/MS. Differential abundance and Spearman correlation analyses were performed in relation to BMD/T-scores and serum biochemical indicators.

Results: Compared with controls, the bone-loss cohort showed lower BMD and T-scores at L1-L4 and at the femoral neck, and a longer period since menopause. Additionally, the bone-loss cohort exhibited modestly higher, yet still subnormal, circulating 25(OH)D and 25(OH)D3 concentrations, which were inversely associated with L1-L4 T-scores. The bone loss group was characterized by a diminished abundance of protective genera Prevotella and Dorea and increased levels of Limosilactobacillus and Olsenella. Prevotella and Dorea showed positive trends with L1-L4 T-scores but did not reach statistical significance. Metabolomic analysis identified 33 differential metabolites, with higher levels of flavonoids (taxifolin), L-arginine, and spermidine in the normal bone group and reduced lysophosphatidylcholine levels. N-acetylanthranilic acid (NAA) was positively correlated with L1-L4 T-scores and the relative abundances of Prevotella and Dorea.

Discussion: Postmenopausal bone loss is associated with gut microbiota alterations and altered serum metabolic profiles. Although circulating 25(OH)D levels were relatively higher (yet still subnormal) in the bone-loss group, this cross-sectional observation should be interpreted as an association rather than evidence of a compensatory mechanism. Our findings indicate that NAA and its associated taxa are correlationally associated with bone-related phenotypes, supporting a testable microbiota-metabolite hypothesis that warrants validation in longitudinal or interventional studies.

Background: The increasing global incidence of ulcerative colitis (UC) calls for urgent attention to the prevention and management of its symptoms. Public awareness and international regulations aimed at banning or reducing antibiotic use require alternative strategies, with probiotics demonstrating promising potential. Recent studies suggest that the combination of different probiotic strains with complementary functions may achieve synergistic effects.

Methods: We selected Lactobacillus acidophilus, noted for its mucosal adhesion, and Pediococcus acidilactici, distinguished for its environmental resilience, to investigate their combined effects on the alleviation of symptoms in a mouse model with DSS-induced colitis.

Results: The results showed that the combined intervention was effective in reducing weight loss in mice with colitis and in mitigating the disease activity score. The combination significantly alleviated conditions such as colonic crypt dysfunction, goblet cell loss, and severe mucosal damage. Serum biochemical indicators revealed that the combined lactic acid bacteria increased the antioxidant capacity of the mice. Furthermore, administration of the combination reduced levels of inflammatory cytokines in colon tissues and increased the mRNA expression levels of tight junction proteins. It partially reversed changes in the gut microbiota in mice with colitis, mainly by increasing the abundance of potentially beneficial bacteria such as Akkermansia, together with increasing short-chain fatty acids production in the cecum.

Discussion: The current study demonstrates that the combination of Lactobacillus acidophilus and Pediococcus acidilactici exerts protective effects against colitis in mice by the enhancement of antioxidant capacity, reduced inflammatory responses, preservation of intestinal barrier integrity, and partial restoration of gut microbiota and its metabolite production. Collectively, the study provides novel insights into the synergistic application of the specific probiotic pair for colitis management.

Introduction: The intestinal microbiota is considered an adaptive trait closely associated with reintroduction success and may contribute to the ecological fitness of B. lenok.

Methods: In this study, intestinal morphology, digestive enzyme activity, immune parameters, and gut microbiota composition were compared between wild and farmed B. lenok to elucidate differences in intestinal and hepatic health under distinct aquatic environments.

Results: Histological analysis showed that villi in the hindgut of wild individuals were longer and denser than those of farmed ones. Although the intestinal structure of farmed B. lenok remained intact, their villus morphology and density differed significantly from those of the wild group. Compared with the farmed group, wild B. lenok showed higher hepatic immune/antioxidant activity (elevated alkaline phosphatase (AKP), acid phosphatase (ACP), lysozyme (LYZ), and catalase (CAT), as well as glutathione (GSH) content) and up-regulated liver immune-related genes (c3, foxo1, igM, il-10, lyz, etc.), while farmed fish displayed higher intestinal stress markers (CAT, malondialdehyde (MDA) and a pro-inflammatory signature (il-6, il-1β upregulated). Microbiota profiling revealed higher abundance of Firmicutes and Bacteroidetes but a trend of decreasing Proteobacteria in the wild group.

Discussion: Collectively, these findings demonstrate significant differences in intestinal morphology, digestive function, and microbial community composition between wild and farmed B. lenok. This study provides new insights for improving post-stocking adaptability in reintroduction programs and proposes novel conservation strategies for biodiversity restoration.

The interaction between the gut microbiota and central nervous system (CNS) diseases has emerged as a major focus in neuroscience and microbiome research. Accumulating evidence shows that gut microbiota influence the pathogenesis of neurodevelopmental, neurodegenerative, autoimmune, and psychiatric conditions via the microbiota-gut-brain axis. However, the underlying mechanisms are complex and not yet fully elucidated. Advances in multimodal magnetic resonance imaging, positron emission tomography, and diffusion tensor imaging, now enable in vivo visualization of associations between gut microbial alterations and abnormalities in brain structure and function, providing new perspectives for understanding the role of gut microbiota in CNS pathology. This review systematically reviews neuroimaging-based research linking gut microbiota to neurological diseases (e.g., Alzheimer's disease, multiple sclerosis, traumatic brain injury), and psychiatric disorders (e.g., schizophrenia, and autism spectrum disorder). It highlights the mediating roles of microbial metabolites, immune-inflammatory responses, and neuroimmune pathways, and discusses future directions integrating multi-omics data with neuroimaging technologies, as well as their potential clinical applications. What distinguishes this review from its predecessors in the same field is its explicit neuroimaging-driven framework rather than general mechanistic discussion.