Search Results (8,746)

Extracellular electron transfer is crucial in the microbial reduction of hexavalent chromium [Cr(VI)], and N-acylated-_L-homoserine lactones (AHLs) could accelerate this process. In this study, fulvic acid (FA) was used as an electron shuttle to enhance the microbial reduction process via stimulating extracellular electron transfer efficiency. Compared with 9,10-anthraquinone-2-sulfonic acid (AQS), FA had a stronger positive effect on Cr(VI) reduction by S. putrefaciens, showing the ability of stimulating S. putrefaciens to release AHLs. The concentrations of C6-HSL, C8-HSL and 3OC10-HSL increased by 11.79 ng/L, 19.82 ng/L and 3.01 ng/L after the addition of 2% FA. The bioinformation analysis indicated that AHLs could regulate the synthesis of electron shuttles by S. putrefaciens, such as riboflavin. And the addition of exogenous C6-HSL, C8-HSL, C10-HSL, C12-HSL and 3OC10-HSL increased the Cr(VI) reduction rates by 1.73%, 2.39%, 4.18%, 1.45% and 2.70%, because they could promote the release of riboflavin. It revealed a new pathway by which FA promoted microbial Cr(VI) reduction. This study also provides a novel approach for enhancing the microbial Cr(VI) reduction and a deeper understanding of the communication mechanism among microorganisms. Full article

Verticillium wilt, a prevalent soil-borne disease, poses a significant challenge to cotton production in Xinjiang, China. Continuous cotton monoculture has increased disease incidence and affected soil microbial diversity in Xinjiang, while crop rotation is recognized as an effective strategy for soil pathogen control. This study investigates how a one-year maize rotation affects Verticillium wilt incidence and soil microbiome composition in cotton fields across northern and southern Xinjiang. The results demonstrated that short-term rotation significantly reduced Verticillium wilt occurrence in both northern and southern Xinjiang. Using high-throughput sequencing of fungal ITS and bacterial 16S rRNA regions, microbial community analysis revealed minimal changes in alpha-diversity but significant structural reorganization between continuous cropping (CC) and rotation (CR) systems, particularly in fungal and bacterial genera composition, with distinct spatial patterns between northern and southern fields. Crop rotation promoted beneficial taxa such as Sphingomonas and Pseudogymnoascus, while reducing the abundance of pathogens such as Verticillium dahliae. LEfSe study suggested Tepidisphaerales and Lasiosphaeriaceae as biomarkers for CR systems, whereas Hypocreales and Blastocatellia dominated in CC soils. Co-occurrence network analysis revealed more bacterial connectivity and modularity under CR, suggesting better microbial interactions and ecological resilience. The increased structural complexity of bacterial networks under CR indicates their greater contribution to soil health maintenance and ecosystem resilience. Our findings demonstrate that short-term crop rotation not only effectively reduces Verticillium wilt incidence but also restructures soil microbial communities, providing an actionable strategy for sustainable cotton cultivation in Xinjiang. Full article

Background: Edentulism, or toothlessness, is a significant public health issue with profound implications for physical and systemic health, especially during pregnancy, when hormonal and behavioral changes increase the risk of oral diseases. Indigenous populations are particularly vulnerable due to socioeconomic and cultural factors that limit access to dental care. Methods: This pilot study assessed the oral microbiota of nine women, both pregnant and non-pregnant, aged 18–35 from the Salasaca indigenous community in Ecuador, using 16S rRNA gene sequencing. Samples were collected from dentin, saliva, and oral mucosa, and analyzed for alpha and beta diversity levels, taxonomic composition, and ecological metrics using the DADA2 pipeline and a canonical correspondence analysis. Results: Pregnant participants exhibited significantly lower microbial diversity compared to non-pregnant individuals, with notable differences in species richness and community structure. Dominant phyla included Bacillota, Bacteroidota, and Pseudomonadota. Prevotella sp., Neisseria sp., and Haemophilus sp. were among the prevalent genera, with the canonical correspondence analysis highlighting associations between microbial profiles and variables such as gestational status, marital status, and BMI. Conclusion: The findings suggest that pregnancy influences the oral microbiota composition, potentially predisposing women to dysbiosis and dental pathology. This study highlights the need for targeted oral health strategies during pregnancy and serves as a foundation for larger studies in underserved indigenous populations. Full article

Rosacea is a chronic inflammatory skin disorder with multifactorial pathogenesis involving immune dysregulation and microbial alterations. This study compared the mycobiomes of skin, blood, and stool samples in rosacea patients and healthy controls to assess fungal diversity, abundance, and possible translocation, as well as associations with bacterial microbiomes. Internal transcribed spacer (ITS) region sequencing was performed on samples from 14 rosacea patients and 8 controls. While distinct fungal community compositions were observed across sample types, no significant differences in fungal diversity or genus abundance were found between the patient and control groups in any compartment. Malassezia dominated the skin mycobiome, while stool samples showed higher abundances of Candida and Saccharomyces, which were inversely correlated. Patients with high skin and blood Malassezia also exhibited increased Cutibacterium abundance, suggesting a potential role in impaired skin barrier integrity. Stool samples with elevated Saccharomyces correlated with higher levels of anti-inflammatory bacteria Prevotella and Agathobacter, whereas Candida dominance showed the opposite. These findings suggest that fungal dysbiosis, in the interplay with bacterial communities, may influence rosacea pathogenesis through the gut–skin axis. This work underscores the significance of integrated microbiome research across multiple biological compartments in order to enhance our understanding and potential targeting of microbial factors in rosacea. Full article

Carbon tetrachloride (CT) is a toxic volatile chlorinated hydrocarbon, posing a serious hazard to ecosystem and human health. This study discussed the bioremediation possibility of groundwater contaminated by CT. Enhanced reductive dechlorination bioremediation (ERD) was used to promote the reductive dechlorination process of CT by adding yeast extract as a supplementary electron donor. The microcosm samples of the Control and Experi group were setup in the experiment, and the CT degradation efficiency and microbial community structure changes over 150 days were monitored. The results showed that the Experi group achieved complete degradation of CT within 40 days, while the control group had no significant change. By analyzing the physical and chemical indexes such as VFAs, sulfate ions, oxidation–reduction potential, pH value and so on, the key changes in the degradation process of CT were revealed. Microbial community analysis showed that specific microorganisms such as Acinetobacter johnsonii, Aeromonas media and Enterobacter Mori played a significant role in the degradation of CT. They may produce hydrogen through fermentation to provide electron donors for the reductive dechlorination of CT. In addition, the genes of reductive dehalogenase synthase related to CT degradation were also identified, which provided molecular evidence for understanding the biodegradation mechanism of CT. The results deliver a scientific basis for optimizing the bioremediation strategy of CT-contaminated groundwater. Full article

This study investigated the effects of applied voltage on methane fermentation using separate reactors for the anode and cathode, with activated carbon felt as electrodes and a constant voltage of 0.7 V. Compared to the control, the cathode reactor exhibited approximately 1.2 times higher methane production and 1.3 times higher methane concentration, whereas the anode reactor showed a reduction to about 0.5 times and 0.8 times, respectively. Microbial analysis revealed that the anode reactor created an electron-accepting environment, promoting the growth of Clostridium sensu stricto 1 and Fastidiosipila, both contributing to organic acid (electron) production. Conversely, the cathode reactor established an electron-donating environment, enhancing methane production by hydrogenotrophic methanogens such as Methanoculleus and Methanobacterium. Although similar methanogen levels were found in the anode reactor, methane production was higher in the cathode reactor. These findings indicate that the anode facilitates organic acid production via electron acceptance, while the cathode acts as an electron donor that promotes hydrogenotrophic methanogenesis. This study provides a clear evaluation of the effects of microbial electrochemical technologies on methane fermentation, demonstrating their potential to stimulate microbial activities and enhance methane production. Full article

Improving agricultural by-product utilization can alleviate tropical feed shortages. This study used corn stover (CS, Zea mays L.) at the maturity stage as the material, with four silage treatments: control, lactic acid bacteria (LAB, Lactiplantibacillus plantarum), cellulase (AC, Acremonium cellulolyticus), and LAB+AC. After 60 days fermentation in plastic drum silos, the silos were opened for sampling. PacBio single-molecule real-time sequencing technology was used to study bacterial community structure, symbiotic network functionality, and pathogenic risk to clarify CS fermentation regulatory mechanisms. The CS contained 59.9% neutral detergent fiber and 7.1% crude protein. Additive-treated silages showed better quality than the control: higher lactic acid (1.64–1.83% dry matter, DM), lower pH (3.62–3.82), and reduced ammonia nitrogen (0.54–0.81% DM). Before ensiling, the CS was dominated by Gram-negative Rhizobium larrymoorei (16.30% of the total bacterial community). Functional prediction indicated that the microbial metabolism activity in diverse environments was strong, and the proportion of potential pathogens was relatively high (14.69%). After ensiling, Lactiplantibacillus plantarum as Gram-positive bacteria were the dominant species in all the silages (58.39–84.34% of the total bacterial community). Microbial additives facilitated the establishment of a symbiotic microbial network, where Lactiplantibacillus occupied a dominant position (p < 0.01). In addition, functional predictions showed an increase in the activity of the starch and sucrose metabolism and a decrease in the proportion of potential pathogens (0.61–1.95%). Among them, the synergistic effect of LAB and AC inoculants optimized the silage effect of CS. This study confirmed that CS is a potential high-quality roughage resource, and the application of silage technology can provide a scientific basis for the efficient utilization of feed resources and the stable development of animal husbandry in the tropics. Full article

Background: Autism spectrum disorder (ASD) is a complex neurodevelopmental disorder characterized by social communication deficits and repetitive behaviors. Recent studies have suggested that gut microbiota may play a role in the pathophysiology of ASD. This study aims to develop a classification model for ASD diagnosis and to identify ASD-associated biomarkers by analyzing metagenomic data at the taxonomic level. Methods: The performances of five different methods were tested in this study. These methods are (i) SVM-RCE, (ii) RCE-IFE, (iii) microBiomeGSM, (iv) different feature selection methods, and (v) a union method. The last method is based on creating a union feature set consisting of the features with importance scores greater than 0.5, identified using the best-performing feature selection methods. Results: In our 10-fold Monte Carlo cross-validation experiments on ASD-associated metagenomic data, the most effective performance metric (an AUC of 0.99) was obtained using the union feature set (17 features) and the AdaBoost classifier. In other words, we achieve superior machine learning performance with a few features. Additionally, the SHAP method, which is an explainable artificial intelligence method, is applied to the union feature set, and Prevotella sp. 109 is identified as the most important microorganism for ASD development. Conclusions: These findings suggest that the proposed method may be a promising approach for uncovering microbial patterns associated with ASD and may inform future research in this area. This study should be regarded as exploratory, based on preliminary findings and hypothesis generation. Full article

The coastal waters of Qinhuangdao are a major hotspot for harmful algal blooms (HABs) in the Bohai Sea, with Noctiluca scintillans being one of the primary algal species responsible for these events. A comprehensive understanding of the microbial community structure and functional responses to N. scintillans bloom events is crucial for elucidating their underlying mechanisms and ecological impacts. This study investigated the microbial community dynamics, metabolic shifts, and the environmental drivers associated with a N. scintillans bloom in the coastal waters of Qinhuangdao, China, using high-throughput sequencing of 16S and 18S rRNA genes, co-occurrence network analysis, and metabolic pathway prediction. The results revealed that the proliferation of autotrophic phytoplankton, such as Minutocellus spp., likely provided a nutritional foundation and favorable conditions for the N. scintillans bloom. The bloom significantly altered the community structures of prokaryotes and microeukaryotes, resulting in significantly lower α-diversity indices in the blooming region (BR) compared to the non-blooming region (NR). Co-occurrence network analyses demonstrated reduced network complexity and stability in the BR, with keystone taxa primarily belonging to Flavobacteriaceae and Rhodobacteraceae. Furthermore, the community structures of both prokaryotes and microeukaryotes correlated with multiple environmental factors, particularly elevated levels of NH₄⁺-N and PO₄³⁻-P. Metabolic predictions indicated enhanced anaerobic respiration, fatty acid degradation, and nitrogen assimilation pathways, suggesting microbial adaptation to bloom-induced localized hypoxia and high organic matter. Notably, ammonia assimilation was upregulated, likely as a detoxification strategy. Additionally, carbon flux was redirected through the methylmalonyl-CoA pathway and pyruvate-malate shuttle to compensate for partial TCA cycle downregulation, maintaining energy balance under oxygen-limited conditions. This study elucidates the interplay between N. scintillans blooms, microbial interactions, and functional adaptations, providing insights for HAB prediction and management in coastal ecosystems. Full article

The excessive emission of cadmium (Cd²⁺) poses a serious threat to the aquatic environment due to its high toxicity and bioaccumulation potential. This study constructed three types of vertical-subsurface-flow constructed wetlands configured with iron–carbon–zeolite composite substrates, including an iron–carbon–zeolite constructed wetland (TF-CW), a zeolite–iron–carbon constructed wetland (FT-CW), and an iron–carbon–zeolite mixed constructed wetland (H-CW), to investigate the purification performance and mechanisms of constructed wetlands for cadmium-containing wastewater (0~6 mg/L). The results demonstrated that iron–carbon–zeolite composite substrates significantly enhanced Cd²⁺ removal efficiency (>99%) through synergistic redox-adsorption mechanisms, where the iron–carbon substrate layer dominated Fe-Cd co-precipitation, while the zeolite layer achieved short-term cadmium retention through ion-exchange adsorption. FT-CW exhibited superior NH₄⁺-N removal efficiency (77.66%~92.23%) compared with TF-CW (71.45%~88.05%), while iron–carbon micro-electrolysis effectively inhibited NO₃⁻-N accumulation (<0.1 mg/L). Under cadmium stress, Typha primarily accumulated cadmium through its root systems (>85%) and alleviated oxidative damage by dynamically regulating antioxidative enzyme activity, with the superoxide dismutase (SOD) peak occurring at 3 mg/L Cd²⁺ treatment. Microbial community analysis revealed that iron–carbon substrates promoted the relative abundance of Bacteroidota and Patescibacteria as well as the enrichment of Saccharimonadales, Thauera, and Rhodocyclaceae (genera), enhancing system stability. This study confirms that iron–carbon–zeolite CWs provide an efficient and sustainable technological pathway for heavy metal-contaminated water remediation through multidimensional mechanisms of “chemical immobilization–plant enrichment–microbial metabolism”. Full article

Extreme environments, such as hypersaline habitats, hot springs, deep-sea hydrothermal vents, glaciers, and permafrost, provide diverse ecological niches for studying microbial evolution. However, knowledge of microbial communities in extreme environments at high southern latitudes remains limited, aside from Antarctica. Laguna Timone is a hypersaline crater lake located in a Pleistocene maar of the Pali Aike Volcanic Field, southern Patagonia; the lake was formed during basaltic eruptions in a periglacial setting. Here, we report the first integrative characterization of microbial communities from biofilms and microbial mats in this lake using high-throughput 16S rRNA and ITS gene sequencing, along with mineralogical and hydrochemical analyses of water, sediments, and carbonates. Bacterial communities were dominated by the genera Enterobacterales ASV1, Pseudomonas, Oscillatoria, Nodularia, and Belliella, with site-specific assemblages. Fungal communities included Laetinaevia, Ilyonectria, Thelebolus, Plectosphaerella, and Acrostalagmus, each showing distinct distribution patterns. These baseline data contribute to understanding microbial dynamics in hypersaline maar environments and support future investigations. This integrative approach highlights key microbe–mineral relationships and underscores the potential of Laguna Timone as a natural laboratory for exploring biosignature formation and microbial adaptation in chemically extreme environments, both on early Earth and potentially beyond. Full article

In this study, we assessed soil pollutants and surveyed the bacterial communities using 16S rRNA sequencing to better understand how to improve rehabilitation strategies for nickel-laterite mines in the Philippines. Representative soil samples and rhizospheres from Saccharum spontaneum L. in three post-mining sites rehabilitated in 2015, 2017, and 2019 were collected and analyzed. X-ray diffraction (XRD) identified iron oxyhydroxides, silicates, and clays as major soil components. Based on the pollution load index and contamination degree, the 2015A and 2015B sites were classified as “pristine” and had a “low degree of pollution”, while the remaining sites (2017A, 2017B, 2019A, and 2019B) were considered “moderately contaminated” with nickel, chromium, cobalt, lead, zinc, and copper. An analysis of the bacterial community composition revealed that the phyla Proteobacteria and Actinobacteria, along with the genus Ralstonia, were the most abundant groups across both control and rehabilitated sites. Our results showed that the soil pH and organic matter contents were strongly linked to specific bacterial community composition. These taxa have potential for inoculation in nickel-laterite soils to promote the growth of hyperaccumulator plants. Our results also showed a significant correlation between the structure of the bacterial communities and nickel, chromium, and manganese soil contents, but not with rehabilitation time. Furthermore, we identified the genera Diaphorobacter as potential bioindicators because they are sensitive to nickel and chromium. This study provides valuable baseline data on heavy metal pollution and microbial diversity in a rehabilitated Ni-laterite mine site. Full article

Alzheimer’s disease (AD), a prevalent neurodegenerative disorder in the aging population, remains without definitive therapeutic solutions. Emerging insights into the gut microbiota (GM) and its bidirectional communication with the central nervous system(CNS) through the microbiota–gut–brain axis (MGBA) have unveiled potential correlative mechanisms that may contribute to AD pathogenesis, though causal evidence remains limited. Dysregulation of GM composition (dysbiosis) exacerbates AD progression via neuroinflammation, amyloid-β (Aβ) deposition, and tau hyperphosphorylation (p-tau), while restoring microbial homeostasis presents a promising therapeutic strategy. Fecal microbiota transplantation (FMT), a technique to reconstitute gut ecology by transferring processed fecal matter from healthy donors, has demonstrated efficacy in ameliorating cognitive deficits and neuropathology in AD animal models. Preclinical studies reveal that FMT reduces Aβ plaques, normalizes tau phosphorylation, suppresses inflammasome activation, and restores microglial homeostasis through modulation of microbial metabolites and immune pathways. Although clinical evidence remains limited to case reports and small-scale trials showing potential therapeutic effect, safety concerns regarding long-term effects and protocol standardization necessitate further investigation. This review synthesizes current knowledge on GM–AD interactions, evaluates FMT’s mechanistic potential, and discusses challenges in translating this ancient practice into a cutting-edge AD therapy. Rigorous randomized controlled trials and personalized microbiota-based interventions are imperative to advance FMT from bench to bedside. Full article

16S rRNA next-generation sequencing (NGS) has significantly advanced cervicovaginal microbiome profiling, offering insights into the relationship between vaginal dysbiosis and HPV-associated carcinogenesis. However, reliance on a limited set of 16S hypervariable regions introduces inherent biases that impact results. This study developed standardized workflows for 16S/ITS NGS, with a focus on identifying methodological biases that influence microbial abundance and taxonomic specificity. Commercial NGS tools were employed, including the 16S/ITS QIAseq V1–V9 screening panel, ATCC vaginal microbial standard, and CLC Genomics Workbench integrated with a customized database (VAGIBIOTA) for analysis. The microbial communities of 66 cervical cytology samples were characterized. Among the regions tested, V3V4 exhibited the least quantitative bias, while V1V2 offered the highest specificity. Microbial profiles and Community State Types (CST) (I–V) were broadly consistent with prior studies, with Lactobacillus abundance clustering into three states: L.-dominant (CST I–III, V), L.-diminished (CST IV-A), and L.-depleted (CST IV-B). Differential abundance analysis revealed that anaerobic opportunistic pathogens dominant in CST IV-B (dysbiosis) were also enriched in HSIL and HPV-16 positive samples. Our findings revealed distinct differences in species identification across 16S rRNA hypervariable regions, emphasizing the importance of region selection in clarifying microbial contributions to HPV-associated carcinogenesis. Full article

Continuous cropping poses a significant threat to sustainable pepper production by triggering soil degradation and growth inhibition, yet the role of root exudates in this process remains unclear. This study aimed to elucidate how continuous cropping duration (0, 1, 2, and 6 years) alters root exudate composition and drives rhizosphere feedback in green pepper. Pot experiments revealed that long-term continuous cropping (6 years) severely inhibited pepper growth, reducing photosynthetic rate (32.02%), chlorophyll content (12.26%), plant height (23.89%), and yield (42.37%). Critically, the relative abundance of 3,4-dimethylbenzaldehyde in root exudates increased progressively with cropping duration. Exogenous application of this compound or long-term monoculture extracts reduced soil pH and increased electrical conductivity, altered the rhizosphere microbial community (notably decreasing Proteobacteria abundance and fungal diversity while increasing Bacteroidota and Firmicutes), and significantly inhibited root development and vitality. Correlation analysis indicated that fungal communities were more responsive to soil property changes, while bacterial communities correlated more closely with root traits. This study demonstrates that the accumulation of specific root exudates, particularly 3,4-dimethylbenzaldehyde, is a key driver of continuous cropping obstacles in green pepper by disrupting rhizosphere microbial community structure and soil properties. This highlights the importance of managing root exudate dynamics, potentially through crop rotation or soil amendments, to mitigate these obstacles. Full article