Search Results (2,026)

Hydrochar application to soil inevitably releases hydrochar-derived dissolved organic matter (HDOM), yet its specific impact on soil microbial communities, independent of the hydrochar solid matrix, remains poorly understood. This study investigated, for the first time, the dose-dependent effects of HDOM on bacterial communities in three distinct soil types (red, yellow-brown, and black soils). A concentration gradient, including undiluted stock solution and 10-, 100-, and 1000-fold dilutions with ultrapure water, was established to test for hormesis-like responses. High-throughput 16S rRNA gene sequencing revealed that HDOM induced profound, soil-specific shifts in bacterial community structure. The application of HDOM induced the emergence of numerous specific bacterial taxa, with unique ASVs reaching up to 15,372. However, no significant changes were observed in microbial community richness or evenness (alpha diversity). Drastic shifts in beta diversity were evident only in red soil and yellow-brown soil, and exclusively under the undiluted HDOM treatment. At the phylum level, HDOM application did not alter the dominant bacterial types (top 10 phyla); however, their relative abundances were jointly regulated by both HDOM dose and soil type. Significant HDOM-induced changes in key bacterial biomarkers were primarily detected in red soil (e.g., phylum Elusimicrobia, class Fimbriimonadia, and family Alicyclobacillaceae) and yellow-brown soil (e.g., phylum Proteobacteria, class Alphaproteobacteria, and family Rhizobiaceae), while in black soil, such changes were observed only under the undiluted HDOM treatment (e.g., species Streptomyces rochei). Predictive functional profiling suggested limited impact on major metabolic pathways, with soil type remaining the primary determinant. These findings demonstrate that HDOM exerts a direct, dose-dependent, and soil-specific influence on bacterial communities, providing key insights into the environmental behavior of hydrochar and guiding its safe application. Full article

Background: This study investigated the mechanisms underlying diarrhea induced by a high-fat diet (HFD) under a state of fatigue, focusing on gut microbiota dysbiosis, bile acid metabolic disturbance, and gut–liver injury. Methods: Mice were assigned to a normal control diet (NCD) group, a HFD-induced diarrhea under fatigue (HFDM) group, and a HFD-induced diarrhea with aggravated dysbiosis (HFDMA) group. Histopathology, inflammatory factors, intestinal barrier-related proteins, small-intestinal microbiota, and colonic bile acid profiles were assessed, and correlation analyses were performed among gut microbiota, bile acids, and inflammatory factors. Results: Compared with the NCD group, both the HFDM and HFDMA groups showed diarrhea-like and fatigue-like phenotypes, histopathological injury in the small intestine and liver, increased tumor necrosis factor-alpha (TNF-α) and interleukin-6 (IL-6) levels, and impaired intestinal barrier function. No significant differences in inflammatory factors were observed between the HFDM and HFDMA groups. Zonula occludens-1 (ZO-1) expression decreased in both model groups but reached statistical significance only in the HFDMA group, whereas Claudin-1 expression was significantly reduced in both groups. Gut microbiota analysis showed altered community structure, with downward trends in alpha diversity that did not reach statistical significance but clear separation trends in beta diversity. Proteobacteria and Streptococcus increased, whereas Ligilactobacillus decreased. Total bile acid levels did not differ significantly among groups; however, the ratio of secondary to primary bile acids was significantly reduced in both model groups, particularly in the HFDMA group, with decreases in representative secondary bile acids, including hyodeoxycholic acid (HDCA) and isolithocholic acid (isoLCA). Correlation analysis further supported close associations among gut microbial alteration, bile acid disturbance, and intestinal and hepatic inflammation. Conclusions: Gut microbiota dysbiosis may disrupt bile acid metabolism, impair intestinal barrier integrity, and promote intestinal and hepatic inflammatory responses, thereby contributing to diarrhea progression under fatigue and HFD conditions through the gut–liver axis. Full article

Arbuscular mycorrhizal fungi (AMF) are widely applied as bioinoculants to enhance crop performance, yet their broader ecological effects on rhizosphere microbial assembly under field conditions remain insufficiently understood. Here, we evaluated the impact of a commercial AMF inoculant and its carrier material on lettuce performance and rhizosphere microbial communities in an open-field experiment. We hypothesized that both viable AMF propagules and formulation components contribute to shifts in rhizosphere processes. Active AMF inoculation significantly increased root colonization and fresh biomass at harvest, confirming successful establishment and enhanced plant performance under field conditions. Colonization levels in the heat-inactivated carrier treatment were comparable to the non-inoculated control, indicating that the carrier did not inhibit indigenous AMF activity or induce nutrient-mediated suppression of symbiosis. Plant physiological responses were stage-dependent, supporting the context-dependent nature of AMF effects in dynamic field environments. High-throughput sequencing revealed no significant treatment effects on bacterial or fungal alpha diversity. However, beta-diversity analyses demonstrated significant compositional restructuring of rhizosphere communities, particularly within the bacterial domain. A stable core microbiome persisted across treatments, yet relative abundances and community evenness were altered by both active inoculation and carrier application. These results suggest that AMF inoculation reorganizes microbial community structure predominantly via shifts in ecological niche occupation. Collectively, our results show that AMF inoculation functions not only as a symbiotic nutrient-acquisition strategy but also as a driver of rhizosphere microbial reorganization under field conditions. Integrating plant performance with microbiome dynamics provides a more comprehensive framework for understanding and optimizing microbial inoculants in sustainable agricultural systems. Full article

Mungbean (Vigna radiata) is an important cash crop, yet the production is significantly compromised by continuous cropping. Beneficial microbial inoculation offers a promising strategy to alleviate the stresses through rhizosphere modulation and host physiological reprogramming. This study evaluated the efficacy of two biological control agents, Bacillus subtilis (B. subtilis) and Trichoderma harzianum (T. harzianum), in promoting mungbean growth under continuous-cropping conditions. Both individual applications of B. subtilis and T. harzianum significantly improved plant biomass, root system architecture, and yield. Combined metagenomic and transcriptomic analyses were conducted to unravel the underlying mechanisms. According to metagenomic analysis, both B. subtilis and T. harzianum were responsible for significant changes in beta diversity without significantly affecting the alpha diversity of the rhizosphere microbial community. T. harzianum recruited Chitinophagaceae unclassified, Abditibacterium, Hydrogenophilaceae unclassified, Methylophilaceae unclassified, and Chimaeribacter, while Bs recruited Candidatus Saccharibacteria unclassified. Transcriptomic analysis indicated that T. harzianum induced more extensive transcriptional reprogramming than B. subtilis. The enrichment analysis revealed both shared and distinct responses triggered by the two treatments. These findings suggest that B. subtilis and T. harzianum alleviate continuous-cropping stress through distinct yet complementary mechanisms involving rhizosphere microbiome modulation and mungbean transcriptional reprogramming. This study provides a sustainable strategy for legume cultivation. Full article

Observations suggest that headwater streams have lower species diversity within a site than larger streams, but higher beta diversity, and thus gamma diversity, across a catchment. This pattern of diversity includes taxonomic richness and genetic diversity, as well as a high degree of endemism. I review several mechanisms that potentially contribute to the overall high diversity of freshwater organisms in headwaters, although these mechanisms are interdependent. These include the high numbers of headwater streams, heterogeneity of habitats and resources, founder effects, colonization dynamics, isolation, and strong selection, all leading to diversification of forms. However, riverscape diversity patterns vary across taxonomic and functional groups, highlighting that patterns of diversity are driven by different processes for different organisms. More explicitly structured sampling designs will better address patterns of taxonomic richness and for a broader range of taxa. It will be interesting to find ways to partition the relative importance of different mechanisms in contributing to the variation in diversity among headwaters. The great importance of headwater streams to global biodiversity conservation is clear, but will be more evident when better assessments of diversity patterns across these small systems are available. Full article

Probiotics are commonly applied to maintain the balance of gut microbiota and regulate the intestinal metabolic function of companion animals. In the present study, complex probiotics (Bacillus coagulans SNZ-1969, Bacillus subtilis, and Bacillus licheniformis) were added into the basal diet of domestic cats to investigate their influence on the intestinal microbiome and metabolic characteristics. Results revealed that the alpha diversity of the gut microbiota in the probiotic group was enhanced when compared to the control group. The beta diversity of the gut microbiota was also altered by the oral consumption of the complex probiotics. Compared to the control group, the relative abundance of beneficial microbes (such as Clostridium, Bacteroides, Phocaeicola, and Ruminococcus) in the probiotic group was enhanced, while the relative abundance of opportunistic pathogens (such as Escherichia, Gallibacter, Corynebacterium) was decreased. Additionally, the intestinal metabolic characteristics of domestic cats were also changed. The metabolomic analysis identified 408 differential metabolites between the two groups, and the KEGG function pathway analysis proved that the dominant pathway related to the differential metabolites were the amino acid metabolism, lipid metabolism, carbohydrate metabolism, energy metabolism, endocrine system, digestive system, immune system, and other metabolic pathways. Spearman’s correlation analysis revealed that the beneficial microbes had positive correlations with the differential metabolites. In conclusion, the current study demonstrated that oral administration of complex probiotics could regulate overall health and well-being in domestic cats through modulating the gut microbiome and metabolic characteristics. Full article

Atopic dermatitis (AD) is a chronic inflammatory skin disease influenced by several factors, including immune system imbalance, impairment of the epidermal barrier, and alterations in the composition of the gut and skin bacterial and fungal microbiota. This study combines metagenomic sequencing and culture-based methods to explore the impact of probiotic supplementation on the cutaneous microbiota and mycobiota of AD patients. Twenty-five adults diagnosed with AD were enrolled, and skin swabs were analyzed to characterize microbial diversity and load. Culturomic analyses identified 42 bacterial and 6 fungal species, confirming Staphylococcus aureus and Candida parapsilosis as predominant taxa. High-throughput sequencing revealed Staphylococcus spp. and Malassezia spp. as dominant genera, with notable interindividual variability. While probiotic use did not significantly influence bacterial diversity, it was associated with higher richness and evenness in fungal communities, as shown by alpha and beta diversity metrics. Malassezia restricta was more prevalent among probiotic users, whereas Candida parapsilosis and Rhodotorula mucilaginosa were enriched in non-users. These findings indicate an association between probiotic use and differences in the composition and diversity of the skin mycobiota compared with the bacterial microbiota, suggesting that fungal communities may be more responsive to probiotic-associated factors. Integrating metagenomic and culturomic approaches offers valuable insights into the complex interactions among host factors, microbial communities, and probiotic use in AD, paving the way for targeted microbiome-based therapeutic strategies. Full article

This study presents a comprehensive flavour profile analysis of 12 Morchella samples (5 cultivated and 7 wild species) collected from diverse regions across China. The contents of free amino acids and volatile organic compounds were determined using UHPLC-QE-HRMS and HS-SPME-GC-MS. Flavour contribution was assessed by calculating taste activity values (TAVs) and relative odor activity values (rOAVs), and the influence of environmental factors on flavour compound accumulation was further explored. The findings indicated that cultivated Morchella exhibited pronounced fruity, floral, sweet, and mushroom-like notes (e.g., 1-octen-3-one, beta-damascone, and 1-(2-aminophenyl)ethanone), rendering them suitable for fresh consumption. In contrast, wild Morchella exhibited higher levels of herbaceous and smoky aroma compounds (e.g., (E,Z)-2,6-nonadienal, benzenemethanethiol, and non-8-enal), suggesting potential for premium product development. Correlation analysis revealed metabolic associations between taste-active amino acids and key volatile organic compounds via intermediates of the lipoxygenase pathway and the tricarboxylic acid cycle. Furthermore, environmental parameters including elevation, annual precipitation, and solar radiation were found to significantly influence the accumulation of flavour-related metabolites. These findings provide insights into the chemical basis underlying the flavour diversity of Morchella and offer a theoretical foundation for species identification, flavour-directed breeding, and differentiated product development. Full article

Background: Patients with kidney failure requiring dialysis experience a high burden of vaccine-preventable diseases, and vaccine hypo-responsiveness is a key contributor. Uraemic toxins and gut dysbiosis are potential causes of hypo-responsiveness. Aim: This study aimed to determine whether uraemic toxin concentrations or gut dysbiosis are associated with vaccine response in haemodialysis patients. Methods: This was a single centre, observational cohort study of maintenance dialysis patients receiving a conventional 2-dose primary COVID-19 vaccination course. Demographic, clinical and vaccination data were collected from the eMR. Vaccine response (Elecsys Anti-SARS-CoV-2 immunoassay), serum uraemic toxin concentrations (indoxyl sulphate, p-cresyl sulphate, and trimethylamine N-oxide by liquid chromatography), and stool microbiome (16S rRNA gene sequencing) were measured 8 weeks after the second dose of vaccine. Results: Forty participants (43% female, mean age 66 years; 59% Caucasian) were included, 70% of whom were classified as a vaccine responder. Antibiotic exposure, prednisolone use and lymphopenia were significantly associated with hypo-responsiveness. Microbiome profiling identified differences in beta diversity between responders and non-responders, positively correlated with short-chain fatty acid producers (Parabacteriodes) and negatively with pathobionts (Escherichia/Shigella). Differential abundance analysis identified lower levels of Tyzzerella, Gemmiger, and Hungatella and higher levels of Turicibacter in vaccine responders. Total uraemic toxin burden and individual toxin concentrations did not differ between responders and hypo-responders (all p > 0.05). Stratification by low versus high/very high toxin burden groupings was not associated with response (p > 0.99). Conclusions: Differences in gut microbial composition were observed between vaccine responder groups, while uraemic toxin concentrations were not associated with vaccine responsiveness. These findings suggest gut microbiota composition may contribute to vaccine hypo-responsiveness in individuals receiving dialysis and warrant further investigation in larger mechanistic studies. Full article

Euonymus bungeanus is a highly valued ornamental tree/shrub species widely utilized in landscaping and afforestation in Northeast Asia, yet molecular studies on this species remain limited due to the lack of validated reference genes for reverse transcription quantitative real-time polymerase chain reaction (RT-qPCR). In this study, 16 candidate reference genes were selected based on classical plant reference genes and our previous transcriptome data. Their expression stability was comprehensively evaluated using 64 samples collected from diverse tissues and plants subjected to various abiotic stress/hormone treatments across multiple time points. Across all samples analyzed, PBG1 (20S proteasome beta subunit G1) exhibited the highest overall expression stability, followed by VAPD (vacuolar ATP synthase subunit D) and EIF4A (eukaryotic translation initiation factor 4A). For tissue-specific analysis, TSR2 (pre-rRNA-processing protein), VAPD, and PBG1 demonstrated the greatest stability. Under specific stress conditions, PBG1 and EIF4A were identified as the most stable genes under low- and high-temperature conditions. PP2A (protein phosphatase 2A) and TUB6 (beta-6 tubulin) were optimal for drought stress, while TSR2, SRP (nuclear speckle splicing regulatory-like protein), and PBG1 exhibited superior stability under salt stress. These findings establish a validated panel of reference genes enabling accurate and reliable gene expression normalization in E. bungeanus, thereby facilitating future functional genomics studies in this economically and ecologically important species. Full article

Wetlands are ecosystems with critical functions. However, the accelerated progression of global urbanization and human activities, including agricultural encroachment, has resulted in a notable decline in wetland areas and the degradation of wetland quality worldwide. Consequently, wetland restoration has become a central focus of wetland research. Plant community characteristics are among the simplest and most frequently used indicators for evaluating wetland restoration progress and are a crucial factor in maintaining the health and stability of wetland ecosystems. Therefore, this study aimed to investigate the plant community characteristics of restored wetlands with different durations of abandonment in the lower Tumen River Basin, which is expected to provide guidance for promoting the restoration of abandoned farmlands in this region. We hypothesize that species diversity decreases with increasing abandonment age, plant community composition converges toward that of natural wetlands over time, and beta diversity declines due to increasing biotic homogenization during succession. We established a chronosequence of abandoned wetlands in the lower Tumen River Basin, with sites abandoned for approximately 5, 15, and 30 years. And we use natural wetlands and paddy fields as references. With natural succession, the dominant plant species in the restored wetlands transitioned from annuals/biennials to perennials. The aboveground biomass initially increased and subsequently decreased. A gradual decline in species diversity was observed along with a further reduction in beta diversity, and the species turnover component consistently exceeded the richness difference component. The pronounced biotic homogenization among communities indicates that achieving a stable state comparable to that of natural wetlands may require considerably more time or may not be attainable solely through natural succession. Full article

Atmospheric nitrogen (N) deposition is an important global change driver in forest ecosystems, yet its long-term effects on belowground microbial communities in cold-temperate coniferous forests remain insufficiently understood. In this study, endpoint shotgun metagenomic sequencing was used to evaluate bulk soil microbial communities after 12 years of experimental N addition in a Larix gmelinii-dominated forest in the Greater Khingan Mountains of northeastern China. Four treatments were included: control (0 kg N ha⁻¹ yr⁻¹), low N (25 kg N ha⁻¹ yr⁻¹), medium N (50 kg N ha⁻¹ yr⁻¹), and high N (75 kg N ha⁻¹ yr⁻¹). Microbial alpha diversity did not differ significantly among treatments, although moderate N addition showed a tendency to maintain relatively higher richness and diversity. In contrast, beta-diversity analysis indicated clear shifts in community composition along the N addition gradient. Pseudomonadota, Acidobacteriota, and Actinomycetota dominated the microbial communities, with Pseudomonadota tending to increase under N enrichment, whereas some oligotrophic groups showed reduced relative abundance. Functional annotation showed that metabolism-related genes remained dominant across treatments, and carbohydrate-active enzyme profiles suggested altered microbial potential for complex carbon decomposition under long-term N input. Nitrogen addition also modified the abundance patterns of some antibiotic resistance genes and mobile genetic elements, although overall resistome differentiation among treatments remained limited. These results provide endpoint metagenomic evidence that long-term N addition can reshape bulk soil microbial community composition and selected functional potentials in cold-temperate coniferous forest soils, even when overall alpha diversity remains relatively stable. Full article

Understanding the mechanisms driving patterns of alpha and beta-diversity through temporal variation in taxonomic diversity remains a fundamental question in community ecology surveys. Insects represent a species-rich group playing several roles in ecological processes. However, knowledge of their temporal distribution and seasonality remains limited, particularly in subtropical regions. We investigated intra-annual patterns of alpha and beta-diversity of butterflies in Restinga ecosystems of southern Brazil, a subtropical region characterised by marked seasonality. Butterflies were monitored throughout one year using Malaise interception traps, and data were grouped by season. We tested seasonal differences in temperature and humidity and evaluated their association with patterns of richness, abundance, evenness, and species composition. Temperature was the main environmental filter structuring butterfly assemblages compared to humidity. Butterfly richness and abundance peaked in summer, followed by spring, coinciding with higher temperatures, while diversity declined markedly during winter. Although we expected winter assemblages to represent nested subsets of other seasons, beta-diversity analyses revealed high species turnover among seasons. Our findings demonstrate that temperature drove the structure of butterfly assemblages across seasons, highlighting the importance of monitoring to increase knowledge on the temporal dynamics and distribution of insects in the subtropical region. Full article

Introduction: Caffeine is the most widely consumed psychoactive stimulant worldwide and acts primarily through antagonism of adenosine A1 and A2A receptors, thereby reducing sleep pressure and promoting wakefulness. Although its alerting and performance-enhancing effects are well established, its influence on sleep-related electroencephalography (EEG) has been investigated across diverse paradigms with substantial methodological heterogeneity. This systematic and mechanistic review aimed to synthesize human evidence on how caffeine affects sleep architecture, quantitative sleep EEG, and neurophysiological markers of sleep homeostasis, and to interpret these findings within current models of adenosine-mediated sleep–wake regulation. Materials and methods: A systematic search of PubMed/MEDLINE, Web of Science, Scopus, Embase, PsycINFO, ResearchGate, and Google Scholar was conducted for studies published between January 1980 and January 2026, with the final search performed on 10 January 2026. Eligible studies were original human investigations examining caffeine exposure or administration and reporting sleep-related EEG outcomes, including polysomnographic sleep staging, spectral EEG analyses, or other EEG-derived sleep metrics. Two reviewers independently screened records and assessed eligibility, with disagreements resolved by consensus. Data on study design, participant characteristics, caffeine interventions, EEG methodology, and outcomes were extracted using a predefined form. Risk of bias was evaluated using the RoB 2 and ROBINS-I tools. Owing to marked heterogeneity across studies, findings were synthesized narratively within a mechanistic interpretive framework. Results: Thirty-two studies were included. Across highly heterogeneous paradigms—including acute bedtime or evening dosing, daytime or repeated caffeine use before nocturnal sleep, administration during prolonged wakefulness followed by recovery sleep, withdrawal protocols, and ambulatory/home EEG monitoring—the most consistent finding was suppression of low-frequency NREM EEG activity, particularly slow-wave activity and the lowest delta frequencies. Caffeine frequently increased faster EEG activity, including sigma/spindle and beta ranges, producing a lighter, more aroused, and more wake-like sleep EEG profile. These effects were especially prominent during early-night NREM sleep and in recovery sleep after sleep deprivation, where caffeine attenuated the expected homeostatic rebound in low-frequency power. REM-related effects were less consistent, but some studies reported delayed REM timing and subtler alterations in REM EEG. Emerging evidence further suggests that caffeine increases EEG complexity and shifts sleep dynamics toward a more excitation-dominant state. Several studies indicated that quantitative EEG measures were more sensitive than conventional sleep-stage variables in detecting caffeine-related sleep disruption. Dose, timing, habitual caffeine use, withdrawal state, age, circadian context, and adenosinergic genetic variation, particularly involving ADORA2A, moderated the magnitude of effects. We also highlighted the connection between current results and sports and sports science. Conclusions: Caffeine reliably alters the neurophysiological architecture of human sleep in a direction consistent with reduced sleep depth and weakened homeostatic recovery. The overall evidence supports a mechanistic model centered on adenosine receptor antagonism, attenuation of sleep-pressure build-up and expression, and a shift toward greater cortical arousal during sleep. Sleep EEG appears to be a sensitive marker of these effects, often revealing physiological disruption even when conventional sleep architecture changes are modest. Future research should prioritize larger and more diverse samples, pharmacokinetic and pharmacogenetic characterization, and ecologically valid high-resolution sleep monitoring to clarify the real-world and functional consequences of caffeine-induced EEG changes. Full article

Hydrological fluctuations drive community dynamics in floodplain lakes, yet their integration into water resource management remains limited. Here, we integrated environmental DNA (eDNA) metabarcoding with hydroacoustic surveys to investigate vertebrate community assembly in China’s largest freshwater lake (Poyang Lake) during the winter dry season. We detected 65 vertebrate species, with Cypriniformes dominating. Beta-diversity partitioning revealed that turnover dominated taxonomic and functional dissimilarity, while phylogenetic beta diversity was characterized by nestedness, which is consistent with environmental filtering. Functional richness declined with water depth, coinciding with hydroacoustic vertical size stratification, indicating niche partitioning along depth gradients. Null model analysis showed stochastic processes (ecological drift) dominated regional assembly (72.97%), whereas joint species distribution modeling attributed explained variation to environmental factors (28.9%, notably water depth) and species associations (29.7%) at local scales. This hierarchical framework, regional stochasticity shaping the species pool and local deterministic filtering structuring communities, reframes environmental flow conceptualization: effective management must preserve the full spectrum of hydrological variability and maintain bathymetrically diverse habitats that support functional niche differentiation. The integrated eDNA-hydroacoustic approach offers a non-invasive, high-resolution toolkit for biological assessment within regulatory water quality frameworks. Full article