Frontiers in Microbiology最新文献

Introduction: The oral microbiome, a complex ecosystem linked to both oral and systemic diseases, undergoes compositional and functional changes with aging. Tobacco exposure is a known disruptor of microbial homeostasis, yet its effect on microbial diversity remains inconsistent. Whether agingmodifies the relationship between smoking and the oral microbiome remains unclear. This study aimed to evaluate (1) the association between serum cotinine and oral microbial diversity, (2) whether this association varies by age, and (3) taxonomic shifts that may explain smoking-related dysbiosis.

Method: We analyzed data from 4,387 adults aged 30-69 years in the U.S. National Health and Nutrition Examination Survey 2009-2012. Serumcotinine, an objective biomarker of nicotine exposure, was used as the primary exposure. Oral microbiome diversity was assessed via 16S rRNA gene sequencing of oral rinse samples. Microbial profiles were analyzed using observed amplicon sequence variants and Bray-Curtis. Alpha diversity declined progressively with age, with the most pronounced reduction among current smokers.

Results: Serum cotinine was inversely associated with alpha diversity, particularly in current smokers aged 60-69 years (adjusted β = -0.1081, p = 0.0002). Beta diversity differed significantly by smoking status (PERMANOVA p < 0.0001). Analysis identified 29 genera were associated with serum cotinine: Haemophilus, Neisseria, and Gemella decreased with higher exposure, while Atopobium and Lactobacillus increased. Tobacco exposure is associated with reduced oral microbial diversity, particularly in older adults.

Discussion: This highlights the synergistic impact of aging and smoking on the oral microbiome and underscores the need for age-specific prevention strategies. Prospective studies are warranted to confirm causality and assess the reversibility of smoking-induced dysbiosis.

Introduction: Phagocytosis is a pivotal component of the human innate immune defense against malaria. This essential defense mechanism is often modulated by various host-derived soluble factors. We investigated the phagocytosis of Plasmodium falciparum- and P. knowlesi-infected erythrocytes (IRBC) by human monocytic THP-1 cells in the presence of periostin (OSF-2), a human secretory protein involved in inflammation and tissue repair. This focus was prompted by the fact that OSF-2 is a potent stimulator of Plasmodium IRBC rosette formation, a parasite-derived cytoadherence phenomenon known to impede phagocytosis.

Methods: Culturable parasite isolates were recruited, and tested with the THP-1 cells and recombinant human OSF-2 protein. The role of OSF-2 in IRBC phagocytosis by the phagocytes was evaluated in the presence and absence of uninfected erythrocytes (URBC), and the receptor involved was investigated with antibody blocking assay.

Results: OSF-2 exerted a dual role. When rosetting was prevented via IRBC purification, OSF-2 increased IRBC phagocytosis. This stimulatory effect was also seen when THP-1 cells were primed with OSF-2 before IRBC exposure. This OSF-2-mediated phagocytosis was CD36-dependent and rapidly reversible upon OSF-2 removal. However, when rosetting was induced by the addition of URBC, the presence of OSF-2 reduced the rate of IRBC phagocytosis.

Discussion: These findings highlight the complex parasite-host interactions influencing the infection pathogenesis.

Carcinogenic microorganisms (including viruses, bacteria, fungi, etc.) disrupt cellular homeostasis to drive tumorigenesis by hijacking the host ubiquitin-proteasome system (UPS) and SUMOylation networks, with oncogenic viruses representing the core agents of this regulatory mechanism. Specifically: - Human papillomavirus (HPV) E6 protein binds E3 ubiquitin ligase E6AP to mediate ubiquitin-mediated degradation of tumor suppressor p53, thereby disabling cell cycle surveillance; the HBx protein of hepatitis B virus (HBV) evades its own ubiquitin-mediated degradation by inhibiting the activity of the E3 ligase SIAH1, while simultaneously upregulating DNA methyltransferases to disrupt host epigenetics; the core protein of hepatitis C virus (HCV) induces methylation of the E6AP promoter, blocking its own ubiquitin-mediated degradation to maintain oncogenic activity; Epstein-Barr virus (EBV) LMP1 activates IRF7 via K63-linked ubiquitination, sustaining NF-xB pathway activation to promote proliferation; Kaposi's sarcoma-associated herpesvirus (KSHV) K3 protein mediates MHC-I molecule ubiquitination-dependent endocytosis, achieving immune evasion. Furthermore, non-viral microorganisms such as Helicobacter pylori CagA and aflatoxin A also participate in carcinogenesis by regulating the UPS/SUMO system. In summary, targeted modulation of the UPS/SUMO system constitutes a core oncogenic strategy for carcinogenic microorganisms (particularly viruses), providing molecular targets for precision cancer therapy.

Canine parvovirus type 2 (CPV-2) and feline parvovirus (FPV) are highly contagious pathogens that pose significant threats to domestic and wild carnivores. Rapid and accurate diagnosis is crucial for outbreak control and wildlife conservation, especially in resource-limited settings. In this study, we developed a one-tube RPA-CRISPR/Cas13a platform for the rapid detection and differentiation of CPV-2 and FPV. Two systems were established: a universal detection system for simultaneous identification of both viruses, and a differential detection system to distinguish between them. By targeting conserved regions of the VP2 gene and optimizing reaction conditions, we achieved high sensitivity and specificity. The universal system exhibited a limit of detection (LOD) of 10² copies/μL, while the differential system reached 10³ copies/μL, with both assays completed within 60 min. Clinical validation using 50 samples showed 100% concordance with q-PCR and sequencing results. This study established a dual detection system that is sensitive, rapid, and suitable for use in primary-level settings and field conditions. It holds significant application value in enhancing the early diagnosis and differentiation of canine and feline parvoviruses, reducing the risk of transmission, and protecting the health of wildlife.

Introduction: Studies have investigated the rumen microbiome composition and functions to improve ruminant agriculture and its environmental impacts. Yet, sample collection for rumen microbiome analysis can be difficult and invasive, hindering the ability to sample large animal populations. Studies have proposed using oral swabs as an alternative to rumen sample collection. Here, we investigated the potential of using the oral bacterial community as a proxy for the rumen bacterial community during the cattle production cycle.

Methods: We investigated the development of the bovine rumen and oral bacterial communities using longitudinal sampling and the applicability of using the oral to predict host phenotypes. To this end, we utilized 16S rRNA gene sequencing to characterize and compare the rumen and oral bacterial community composition over multiple time points using amplicon sequence variants (ASVs) in a beef cattle population of 166 animals. Additionally, host phenotype of weaning weight was predicted using the Bayesian ridge regression model to evaluate the applicability of using the oral bacterial community for phenotype prediction.

Results: Our results identified the rumen and oral bacterial communities to have different trajectories of assembly. The proportion of Proteobacteria and Actinobacteriota was higher (p < 0.0001) in the oral samples. Whereas rumen samples had greater abundance of members of the phyla Bacteroidota, Firmicutes, Verrucomicrobiota, Fibrobacterota, and Spirochaetota. The investigation of the oral and rumen bacterial community establishment demonstrated considerable dynamism, where diet and age-related factors to contribute toward bacterial colonization through introduction of new species and the proliferation of early colonizers. Finally, a Bayesian ridge regression model was developed to estimate weaning weight using the centered and scaled log-transformed relative abundance of ASVs. The proportion of variation explained in weaning weight by the oral and rumen bacterial communities were 30 and 37%, respectively.

Discussion: Results from this study suggest that oral and rumen bacterial communities are distinctive, and the oral bacterial community may not serve as a good proxy for the rumen bacterial community even in adult animals with a well-established microbiome. However, the oral bacterial community may serve as a proxy for phenotypic traits of interest in beef cattle.

Introduction: Hepatitis E virus (HEV) is an important zoonotic pathogen, and deer serve as a potential wildlife reservoir capable of contributing to human infections through wildlife-livestock-human transmission pathways. Accurate estimates of HEV prevalence in deer are essential for understanding zoonotic risks and informing surveillance strategies.

Methods: We conducted a systematic search across five major databases. Among 134 publications screened, 33 studies met the inclusion criteria for meta-analysis. Pooled prevalence estimates were calculated, and subgroup analyses were performed by region, development status, time period, age, sex, and diagnostic method. Serological assays (ELISA) and molecular assays (RT-PCR and RT-qPCR) were evaluated separately.

Results: Significant geographical and demographic variation in HEV prevalence was observed. North America showed the highest pooled prevalence (29.57%, 95% CI: 0.00-89.25), with Mexico reporting the highest national estimate (62.68%, 95% CI: 54.54-70.47). Developing countries exhibited higher prevalence (21.45%, 95% CI: 7.12-40.63) than developed countries (5.01%, 95% CI: 2.40-8.43). HEV infection decreased over time, with lower prevalence after 2010 (4.92%, 95% CI: 1.57-9.83) compared with before 2010 (13.17%, 95% CI: 6.01-22.45). Adults had higher infection rates (23.02%, 95% CI: 9.04-41.06) than juveniles (10.11%, 95% CI: 5.83-15.41), and females slightly exceeded males (6.25% vs. 5.07%). Serology indicated past exposure (10.48%, 95% CI: 4.29-18.92), while molecular methods reflected active infection, with pooled rates of 8.58% for RT-PCR and 5.22% for RT-qPCR.

Discussion: Our findings reveal substantial heterogeneity in HEV prevalence among deer and highlight the importance of standardized diagnostic protocols. These results underscore the need for harmonized surveillance to better assess zoonotic risks and support public health strategies targeting HEV transmission at the wildlife-human interface.

Monitoring seasonal changes in coral holobionts throughout the year is essential for understanding coral resilience and symbiotic responses. Previous studies have focused on short-term or specific seasonal changes, limiting their ability to capture annual variations. This study on Galaxea fascicularis in the South China Sea integrates physiological, symbiotic, and transcriptomic analyses across all seasons. In spring, upregulation of Symbiodiniaceae photosynthetic genes and lipid synthesis genes enhances coral photosynthesis and lipid accumulation, promoting growth and reproduction. During July-September, seawater temperatures at the Wuzhizhou Island approached the coral bleaching alert level 2. Summer heat stress reduced photosynthetic capacity, shifted corals to heterotrophy (Δ^{h-z 13}C < 0), and increased MDA content threefold. Signaling pathways, antioxidant systems, and immune pathways were activated. Coral recovery began in autumn and winter after the summer heat and reproduction. In autumn, autotrophy increased, and immunity was activated to repair oxidative damage. In winter, processes for skeleton growth, energy storage, and metabolism were enhanced. Endosymbiotic Durusidinium remained stable, while Endozoicomonas abundance decreased in summer. In winter, potential pathogenic bacteria like Acinetobacter increased. These findings highlight the coral holobiont's synergistic response to seasonal changes, validating coral resilience and guiding artificial restoration strategies.

Introduction: Microbial communities and their associated carbon, nitrogen, and phosphorus metabolic processes play a role in maintaining ecological functions and nutrient cycling in riparian zones. However, systematic research on the coupling mechanisms of carbon, nitrogen, and phosphorus biogeochemical processes in soil profiles of semi-arid riparian soil is still limited.

Methods: This study focused on the riparian zone of the Tuwei River, a typical semi-arid river. Metagenomic sequencing was used to analyze the composition of microbial communities and their carbon, nitrogen, and phosphorus metabolic functions across different soil depths along the river.

Results: The dominant taxa across all depths and river sections were Proteobacteria (average relative abundance 49.85%) and Serratia (11.23%). Results from ANOVA and Tukey-Kramer post-hoc multiple comparison tests showed that microbial diversity significantly decreased with increasing soil depth (p < 0.05). Gene families associated with carbon fixation (accC, pccB), denitrification (nosZ, nirK), and phosphorus metabolism (purC, guaB, pyrG) were significantly enriched in surface soils and showed clear depth-dependent declines (p < 0.05). Partial Mantel tests revealed that microbial metabolic functions were significantly correlated with porosity (p < 0.05), soil organic carbon, total nitrogen, and total phosphorus, confirming that nutrient availability and soil structure are key regulators of microbial biogeochemical functions.

Conclusion: Our findings reveal that nutrient availability and soil structure jointly regulate the vertical distribution of microbial metabolic functions. These insights provide a scientific basis for ecological restoration and soil management in semi-arid riparian zones, where optimizing surface structure and nutrient inputs can stimulate microbial-driven biogeochemical cycling. Key functional taxa and genes may also serve as sensitive indicators for evaluating restoration effectiveness under climate-induced stress.

Introduction: Long-term agricultural management can substantially alter soil microbial communities. The vertical distribution and ecological roles of micromycetes in deep soil profiles of perennial orchard systems remain poorly understood. This study examines the abundance, taxonomic composition, and stratification of micromycetes in dark gray soils of apple orchards cultivated continuously for over 90 years, with the aim of identifying microbiological hotspots and assessing their potential ecological functions.

Methods: Soil samples were collected from 0-100 cm depths and analyzed using standard microbiological methods. Quantitative assessments of fungal abundance were based on colony-forming unit (CFU) counts, while qualitative analysis included isolation and identification of micromycetes to the species level. Structural indices were calculated to characterize species diversity, community stability, and vertical differentiation across soil layers.

Results: Micromycete abundance remained consistently high throughout the soil profile, ranging from 113 to 138 × 10³ CFU g^-1, indicating persistent fungal activity across depths. A total of 68 species belonging to 22 genera and three phyla (Mucoromycota, Mortierellomycota, and Ascomycota) were identified. Ascomycota dominated the mycobiome, accounting for 85% of species diversity. Aspergillus (14 species) and Penicillium (13 species) were present at all depths, suggesting their central role in shaping microbial hotspots. Rare taxa, such as Mucor hiemalis, Cladosporium cladosporioides, and Humicola spp., occurred at low frequencies (0.3-3.4%), contributing to community heterogeneity. Importantly, Fusarium culmorum, typically associated with chernozem soils, was detected for the first time in dark gray soils at 20-60 cm depths. Structural indices revealed clear stratification between surface and subsurface horizons, with greater species richness and community stability observed in the 0-60 cm layers.

Discussion: These findings demonstrate that long-term orchard cultivation supports vertically structured micromycete communities, with specific soil layers acting as microbiological hotspots essential for maintaining soil ecosystem functions. The substantial proportion of phytopathogenic taxa (28%) underscores potential risks to orchard health, while the novel detection of F. culmorum suggests shifts in fungal distribution driven by prolonged land use.

Background: There are no studies of pancreatic pseudocyst infections related to microorganisms. The purpose of this study was to analyze the microbiological differences between infective and non-infective pseudocysts.

Methods: This was an observational cohort study. Thirty-seven patients with pancreatic pseudocyst who underwent EUS drainage at our center were included in the study. According to postoperative infection, the patients were divided into infected group and non-infected group. Capsular fluid was collected during endoscopic drainage and microbial sequencing was performed.

Results: The clinical features of the two groups were similar (p > 0.05). There was no significant difference in α diversity between infected and non-infected groups (p > 0.05). There was significant difference in β diversity between infected and uninfected groups (Adonis, R ² = 0.039, p = 0.019). Random forest maps identified the top five species with the greatest abundance differences. At the genus level, the relative abundance of Klebsiella, Streptococcus, Collinsella, Phascolarctobacterium, and Megamonas in the sac fluid of infected group was significantly higher than that of non-infected group.

Conclusion: The differences in the microbial composition of the cyst fluid in pancreatic pseudocyst may have an impact on postoperative infections. The relative abundance of Klebsiella, Streptococcus, Collinsella, Phascolarctobacterium, and Megamonas in infected group was significantly higher than that in noninfected group. Further research is still needed in the future to confirm this.