Search Results (1,295)

Anaerobic biodegradation is the most affordable method for the degradation of N,N-dimethylformamide. However, the degradation efficiency depends on the concentration. To elucidate the responses of microbial community to N,N-dimethylformamide load, microbial diversity, composition and functional changes at different concentrations of 100, 2000, and 3500 mg/L were analyzed. Results showed that as the N,N-dimethylformamide influent concentration increased from 100 to 2000 mg/L, the removal rate stabilized at 90%, whereas it decreased to ~75% at concentrations over 2000 mg/L. Microbial community diversity increased, and specialists were enriched at 3500 mg/L. Patescibacteria (42.88% and 42.90%), Bacillota (18.52% and 18.54%), and Pseudomonadota (7.13% and 7.09%) were the dominant phyla at 100 mg/L and 2000 mg/L, respectively, and Patescibacteria (16.88%) and Pseudomonadota (15.34%) were the dominant phyla at 3500 mg/L. Methylotrophic methanogeneic (Methanolobus and Methanomassiliicoccus) and syntrophic electron-donating bacteria (Clostridiumand and Trichococcus) were significantly enriched. DMF-degrading genes (fdh, rfA/nrfH, and ATPase) and methylotrophic methanogenesis genes (mcr, mta, and mtm) were significantly upregulated. Therefore, the degradation of N,N-dimethylformamide was characterized by a parallel carbon flux distribution, “methylamine-driven methanogenesis + further oxidation/integration of single-carbon intermediates”, and the nitrogen flux tended to enter a reductive nitrogen cycle characterized by retention and reuse. Full article

This study developed two Causal Graphical Models (CGMs) to analyze the transitions associated with Bacterial Vaginosis (BV) and to identify key bacterial species at each stage. BV results from an imbalance in the vaginal microbiota, whose composition varies among women and across developmental stages. A previous CGM identified influential bacteria but did not address changes between microbiota states. Here, we extend that framework to capture these associations. Path Analysis, a structural equation modeling method based on observed variables that estimates effects through correlations and covariances, was applied to a dataset of 132 pregnant women (4–24 weeks of gestation) from Tabasco, Mexico, previously collected by third parties during healthy pregnancy campaigns and associated with BV diagnosis. Models were validated using statistical metrics and evaluation by a clinical microbiologist. The first model, representing the transition from normal microbiota (BV−) to an indeterminate state (I), identified Megasphaera Type 1 as significant. The second model, from I to bacterial vaginosis-positive (BV+), identified Atopobium vaginae and Bacterial Vaginosis-Associated Bacterium Type 2 as significant contributors. These findings highlight the importance of the intermediate state in dysbiosis progression and support the use of CGMs for studying microbiome dynamics. Full article

Lignocellulose is degraded in the rumen by diverse microorganisms. This study aimed to select the top ruminal microbes associated with an anaerobic fungus (AF) capable of forming consortia that facilitate biogas production from wheat straw. The workflow included the following steps: (1) batch reactors, divided into three compartments with porous membrane bags containing wheat straw, were assembled. The outermost compartment was inoculated with freshly collected rumen content. The first microbes colonizing the wheat straw in the innermost compartment within 72 h were identified. (2) Synthetic consortia were assembled comprising the following identified microbes: an anaerobic fungus (AF) (Neocallimastix lanati); methanogenic archaea (M) (Methanobrevibacter ruminantium or Methanobrevibacter gottschalkii); bacteria (B) (Butyrivibrio hungatei or Succinoclasticum ruminis). (3) Wheat straw was subjected to 7-day pretreatments with these synthetic consortia. (4) The pretreated straw served as substrate in biochemical methane potential (BMP) tests that used a biogas reactor digestate as the inoculum. The pretreated straw produced elevated biomethane yields; nonetheless, this process needs further optimization. The cross-kingdom AF + M + B consortia increased methane production by 35–70%, and superior volatile fatty acid production was confirmed via HPLC. The results suggest novel strategies for advanced practical biogas/biomethane technologies. Full article

Freshwater sediments play a central role in regulating methane (CH₄), carbon dioxide (CO₂) and nitrous oxide (N₂O) dynamics, yet the biogeochemical constraints shaping their short-term responses to redox change remain poorly resolved. Here, we used controlled aerobic and anaerobic slurry incubations of natural lake sediments to identify the environmental drivers governing early-stage greenhouse gas (GHG) dynamics. CH₄ exhibited minimal variation and no significant differences between live and sterilized treatments, indicating that methane turnover during the first hours of incubation is constrained primarily by rapid geochemical adjustments rather than by detectable microbial activity. In contrast, CO₂ and N₂O displayed clear biotic signals consistent with fast-responding respiratory and nitrogen-reducing processes. Across multivariate analyses and Random Forest models, redox-sensitive solutes (Fe³⁺, Fe²⁺, NO₃⁻, SO₄²⁻), together with dissolved organic carbon and NH₄⁺, emerged as key components of the biogeochemical framework structuring early GHG responses, highlighting coupled C–N–Fe controls on short-term gas dynamics. Microbial community analyses revealed the presence of methanogenic archaea (e.g., Methanomicrobiales, Methanofastidiosales), aerobic methanotrophs (Methylomonadaceae, Methylococcaceae) and nitrogen-transforming bacteria; however, their functional expression was limited during the short incubation period. Our results demonstrate that the earliest CH₄, CO₂ and N₂O responses in lake sediments are governed predominantly by rapid geochemical processes that regulate electron-acceptor availability and substrate chemistry, while microbial community composition plays a secondary role at short timescales. Full article

Members of the class Campylobacteria are microaerophilic bacteria widely distributed across diverse environments and are abundant in hydrothermal systems. However, cultivated representatives, particularly from shallow-water vents, remain limited. Here, we investigated the genomic diversity and environmental adaptation of the genus Sulfurospirillum. Phylogenomic analysis revealed a clear separation between terrestrial and marine clades, with relatively few cultured representatives in the marine lineage. Strain 1307, isolated from shallow-water hydrothermal vents, expands the genomic representation of this underexplored clade. Pan-genome analyses based on complete genomes revealed an open pan-genome, indicating ongoing diversification of genus Sulfurospirillum. Further comparison between hydrothermal vent (HTV) and non-HTV lineages identified distinct adaptive features. Vent-associated strains are enriched in genes involved in sulfur metabolism, carbon fixation, the glycine cleavage system (GCS), and the biosynthesis of key cofactors (spermidine, thiamine, lipoate, and heme), reflecting metabolic adaptation to hydrothermal environments. Beyond well-established processes such as sulfur metabolism and autotrophic carbon fixation, the widespread presence of the GCS in vent-associated lineages suggests its potential role as an auxiliary carbon fixation pathway under anaerobic conditions. Overall, this study expands the phylogenetic and genomic diversity of Sulfurospirillum and offers new insights into the mechanisms underlying environmental adaptation and niche differentiation in vent-associated Campylobacteria. Full article

The oral cavity is home to a diverse community of microbiota comprising bacteria, viruses, protozoa, and fungi. These microorganisms inhabit several oral niches and play a significant role in supporting both oral and systemic health. The fine balance between the microbial communities can be influenced by genetics and environmental factors, potentially leading to dysbiosis. Alterations in the oral microbiota have been implicated in periodontitis, chronic inflammation, and systemic disease. Tobacco has been identified as a major player in altering the oral microenvironment and disturbing the balance between potentially pathogenic and beneficial commensals. The resulting dysbiosis promotes inflammation and assists in the passage of pathogenic microorganisms into the blood system. This narrative review examines current evidence linking the use of tobacco with the dominance of pathogenic oral bacteria and a dysfunctional immune response. We explore how the chemicals and toxins in cigarettes promote a reduction in oxygen and cause changes in the abundance of anaerobic bacteria. After discussing the mechanistic pathways leading to periodontitis and the entry of microorganisms into the circulation, the review will interrogate previous studies and identify opportunities and priorities for future research. Full article

Periodontal disease is one of the most common oral conditions in dogs. The oral microbiome plays a key role in maintaining oral health, yet the normal canine oral microbiota and the effects of dental cleaning remain understudied. This study investigated changes in the oral microbiota of healthy dogs after routine tartar removal. Fourteen healthy adult Beagles underwent dental cleaning under general anesthesia. Oral microbiota was sampled using swabs at D-03 (baseline), D0 (after tartar removal), D3, D7, D14, and D28. Microbiota composition was analyzed using 16S rRNA gene sequencing (V4 region). Alpha diversity analysis showed that tartar removal was associated with a significant decrease in richness (Kruskal–Wallis test, p < 0.001) but not with diversity (Shannon). Beta diversity analysis revealed significant differences (PERMANOVA; p < 0.05) across all sampling times compared with baseline. Dental tartar removal temporarily reduced several anaerobic taxa and increased aerotolerant bacteria, with partial recovery toward baseline within two weeks, indicating resilience of the oral microbiota. Porphyromonas dominated the oral microbiota but decreased following dental cleaning with concomitant increases in other bacterial species, notably Neisseria, Moraxella, and Pasteurella. These findings suggest that the canine oral microbiota demonstrates considerable resilience following mechanical disruption by dental cleaning. Future studies should focus on the importance of this microbial restructuring in the pathogenesis and clinical management of canine periodontitis and may inform the development of microbiota-targeted preventive or therapeutic strategies in veterinary dentistry. Full article

Anaerobic digestion is a key technology for chicken manure valorization, but ammonia accumulation often causes system instability. In this study, a 100-day continuous stirred tank reactor (CSTR) experiment was conducted under mesophilic conditions to investigate the mechanisms of ammonia inhibition in chicken manure at total solids (TS) contents of 8% (T1), 12% (T2), and 16% (T3). Compared to T1, the peak TAN concentrations in T2 and T3 were 64.28% and 73.82% higher. After 100 days, pH in T2 and T3 dropped by 5.19% and 7.65% relative to T1. Volatile fatty acid (VFA) accumulation increased by 4.6- and 6.5-fold, while the TS-based methane yield decreased by 52.94% and 73.11%, respectively. Metagenomic analysis revealed the mechanisms of ammonia inhibition: high-ammonia conditions not only directly suppressed the gene abundance of methanogenic pathways but also systematically reduced the abundance of hydrolytic bacteria and acidogenic fermentative bacteria, leading to a disruption in the supply chain of methanogenic precursors, while ammonia-tolerant microbiota became competitively enriched. This study elucidates the multi-level mechanism of ammonia inhibition in high-TS chicken manure digestion at the functional gene level, providing a theoretical basis for the precise regulation of ammonia stress and improvement of system stability. Full article

Intervertebral disc degeneration (IDD) is a fundamental pathological basis of low back pain, yet its pathogenic mechanisms remain incompletely understood. Infection by low-virulence anaerobic bacteria has recently been recognized as a potential etiological factor. In this study, Cutibacterium acnes (C. acnes) was detected in 13.7% of degenerated intervertebral disc (IVD) tissues, and its presence was significantly associated with younger patients and Modic changes. In vitro experiments demonstrated that C. acnes supernatant induces oxidative stress, apoptosis, and extracellular matrix (ECM) degradation in nucleus pulposus (NP) cells in a dose-dependent manner. RNA sequencing and functional validation further indicated that these pathological effects are mediated through activation of the p38 MAPK signaling pathway. Pharmacological inhibition of p38 with the specific inhibitor BIRB-796 effectively reversed the observed cellular damage. Wogonin exhibited negligible cytotoxicity toward NP cells and significantly attenuated C. acnes supernatant-induced oxidative stress, apoptosis, and ECM metabolic imbalance by inhibiting the phosphorylation of p38, JNK, and ERK1/2 within the MAPK pathway. Furthermore, in vivo experiments confirmed that Wogonin alleviated disc height loss, reduced T2-weighted signal attenuation, and mitigated histological damage induced by C. acnes in rat models, thereby restoring the balance between ECM synthesis and degradation. Collectively, this study demonstrates for the first time that C. acnes supernatant exacerbates IDD through activation of the p38 MAPK signaling pathway. It further shows that Wogonin can specifically inhibit this pathway and effectively ameliorate C. acnes-mediated IDD damage in both in vitro and in vivo models. These findings expand the theoretical framework of infection-related mechanisms underlying IDD and identify potential therapeutic targets and candidate agents for the treatment of IDD associated with C. acnes infection. Low back pain is a common health issue affecting populations worldwide, with intervertebral disc degeneration as its core etiology. However, the pathogenic causes in some patients, especially young individuals, remain incompletely understood. This study found that Cutibacterium acnes, a low-virulence bacterium commonly colonizing human skin and mucous membranes, produces metabolic products that can induce damage to the core cells of the intervertebral disc, exacerbate disc degeneration, and this process is associated with the abnormal activation of specific cellular signaling pathways. Through clinical sample detection, cell experiments, and animal model validation, we confirmed that infection with this bacterium is closely related to young patients and specific spinal imaging changes. Meanwhile, we identified Wogonin, a natural compound extracted from Scutellaria baicalensis, which can effectively inhibit the aforementioned abnormal signaling pathways, alleviate cell damage caused by bacterial metabolic products, and improve the pathological state of intervertebral disc degeneration. This study not only reveals the role of low-virulence bacterial infection in intervertebral disc degeneration and provides a new explanation for the pathogenic mechanism in young patients but also offers a natural antibiotic-free candidate for addressing bacterial resistance. It holds significant reference value for the clinical diagnosis and treatment of spinal diseases as well as the development of related drugs. Full article

The stabilization of two-stage bioenergy systems and optimization of the energy recovery efficiency have been found to be closely related to the management of VFA-rich effluent obtained after the dark fermentation of food waste. In this study, the performance of a mesophilic UASB reactor was investigated at different OLR levels. The focus of this study was to assess methane yield and substrate degradation during anaerobic digestion. The results revealed that the performance of the UASB reactor was stable within the range of 2.5–7.0 kg COD m⁻³ d⁻¹. At this range, it was possible to convert VFAs into methane gas through the synergistic interaction of fermentative bacteria and methanogenic archaea. The methane content was 67.9%, TCOD removal efficiency was 89.7% at the optimal OLR of 7.0 kg COD m⁻³ d⁻¹, and volumetric methane production rate was 2.41 L_CH4 L⁻¹ d⁻¹. The increase in OLR to 10.0 kg COD m⁻³ d⁻¹ resulted in instability of the anaerobic digestion process. The instability of the anaerobic digestion process was characterized by propionate accumulation and a high VFA/alkalinity ratio of 0.89. The Grau second-order and Modified Stover–Kincannon models were found to describe COD removal efficiency. The Monod model was found to show limited preliminary agreement under the conditions tested for high-rate granular sludge. The highest methane yield and efficiency of energy recovery were obtained at 7.0 kg COD m⁻³ d⁻¹. The recoverable energy obtained at this OLR was 2.04 MJ d⁻¹. The results of this study revealed that it is possible to integrate dark fermentation and anaerobic digestion through the use of UASB reactors. Full article

Radionuclide contamination of surface water bodies poses a significant environmental challenge, particularly for low-productivity dystrophic systems where natural self-purification capacity is limited. This study aimed to assess the potential of phytoplankton and bottom sediments as biogeochemical barriers for radionuclides. Laboratory modeling of ⁹⁰Sr, ²³³U, ²³⁹Pu, and ²⁴¹Am accumulation was conducted using samples of Lake Dryazlo (Tver Oblast) water and bottom sediments as a representative dystrophic model system. Sorption onto phytoplankton biomass over a single growing season was estimated at 1.89 × 10⁴, 5.41 × 10⁴, 6.64 × 10⁴, and 4.04 × 10⁴ Bq g⁻¹ dry biomass for ⁹⁰Sr, ²³³U, ²³⁹Pu, and ²⁴¹Am, respectively. Actinide immobilization in bottom sediments depended on mineral composition and microbial community activity. Ammophos addition increased radionuclide removal from the liquid phase by 2–5-fold through enhanced phytoplankton productivity, and promoted actinide fixation via phosphate mineral phase formation and stimulation of anaerobic sulfur- and iron-cycling bacteria. These results demonstrate a viable biogeochemical barrier approach applicable to the decommissioning of radioactive waste storage ponds and remediation of radionuclide-contaminated water bodies. Full article

Hidradenitis suppurativa (HS) is a chronic inflammatory dermatosis characterized by recurrent nodules, abscesses, and sinus tract formation in intertriginous skin. Although HS is increasingly recognized as an autoinflammatory condition rather than a classical infection, antimicrobial therapies remain central to disease management, implicating a potential role for the cutaneous microbiome in disease activity. Recent advances in culture-independent sequencing techniques have enabled more detailed characterization of microbial communities in HS, revealing consistent alterations in microbial composition and diversity. Compared with healthy skin, HS lesions exhibit reduced microbial diversity, depletion of commensal organisms such as Cutibacterium acnes, and enrichment of anaerobic bacteria including Prevotella, Porphyromonas, and Finegoldia. These alterations are more pronounced in chronic, tunnel-forming disease and are frequently associated with biofilm formation, which may contribute to treatment resistance and persistent inflammation. Microbiome changes have also been observed beyond overtly lesional skin, suggesting a broader field effect. Evidence regarding extracutaneous microbial compartments, particularly the gut microbiome, remains limited and heterogeneous, while methodological variability in sampling, sequencing, and treatment exposure continues to complicate cross-study comparisons. Emerging data further suggest that immune-targeted therapies, including biologic and small-molecule agents, may indirectly influence microbial community structure through modulation of the inflammatory milieu. Collectively, the available evidence supports cutaneous dysbiosis as a characteristic feature of HS that may potentially interact bidirectionally with immune dysfunction. Future longitudinal, multi-omic studies integrated with clinical phenotyping will be critical to clarify causal relationships and to determine whether microbiome modulation can be leveraged to improve therapeutic outcomes in HS. Full article

Odontogenic sinusitis (ODS) is a common cause of unilateral maxillary sinusitis arising from periapical lesions (PALs) or other dental sources. The infection is typically polymicrobial and dominated by anaerobic bacteria, which are often under detected by routine culture. Molecular approaches such as quantitative polymerase chain reaction (QPCR) and next-generation sequencing (NGS) may provide improved characterization of the microbial burden and community structure. This study aimed to compare culture-based methods, targeted quantitative PCR, and 16S rRNA sequencing in paired samples to characterize microbial composition of ODS and evaluate diagnostic performance. Paired sinus mucosal biopsy (SIN) and periapical lesion (PAL) samples were collected from 28 patients with clinically confirmed ODS. Bacterial detection was performed using conventional culture and targeted QPCR assays for ten clinically relevant taxa. In three randomly selected patients, paired samples were additionally analyzed by 16S rRNA gene amplicon sequencing. Microbial load, taxa richness, and similarity between the two anatomically connected sites were assessed using Wilcoxon signed-rank, McNemar, Jaccard distance, and Bray–Curtis dissimilarity analyses. Results: Culture showed low sensitivity, identifying a limited number of pathogens, primarily Staphylococcus aureus, Streptococcus anginosus, and Fusobacterium nucleatum, in a minority of samples. In contrast, QPCR demonstrated substantially higher detection rates, particularly in PAL samples. Porphyromonas gingivalis (96.8%), Fusobacterium spp. (100.0%), and the S. anginosus group (90.3%) were highly prevalent in PAL specimens, with overlapping but lower detection in SIN samples. PAL samples exhibited significantly higher bacterial loads and taxa richness than paired SIN samples (Wilcoxon p = 0.0004). 16S rRNA sequencing confirmed polymicrobial communities at both sites and identified additional taxa not included in the QPCR panel. Similarity analyses revealed pronounced interindividual variability, ranging from near-identical to highly divergent paired microbiota. Periapical lesions act as reservoirs of predominantly anaerobic bacteria that may seed the maxillary sinus in ODS. Although microbial overlap exists, sinus communities display lower burden and site-specific compositional shifts. Culture-based diagnostics underestimate ODS microbial complexity, whereas combined molecular approaches provide a more comprehensive and clinically informative assessment. Full article

Anaerobic digestion is crucial for safe treatment and energy recovery from municipal sludge. However, seasonal variations in sludge physicochemical properties challenge the continuous, stable operation of anaerobic digestion systems. To investigate the seasonal variations in characteristics of municipal sludge and their impact, this study collected sludge samples from a Beijing plant over a year, analyzed their properties and microbial communities, and evaluated their biogas potential through four-week batch anaerobic digestion tests. The results demonstrated that spring sludge exhibited the highest organic matter (68.7% of total solids, TS), including soluble proteins, sugars, and lipids, while the lignocellulose content peaked in autumn (17% TS). These fluctuations were primarily driven by variations in rainfall, temperature, and human activities. The microbial community shifted significantly: Proteiniclasticum and other hydrolytic bacteria were dominant in spring, whereas Candidatus_Microthrix was notably enriched in winter. Consequently, the biochemical methane potential (BMP) was highest in spring (342.5 mL/g volatile solids) and lowest in autumn (255.8 mL/g volatile solids). Spearman’s correlation analysis indicated a significant positive correlation between BMP and soluble protein content, and a weak negative correlation with cellulose content. These findings provide essential data support for seasonal regulation of sludge anaerobic digestion systems, facilitating strategies to achieve stable biogas production. Full article

Gastroesophageal reflux disease (GERD) is a common chronic disorder of the upper gastrointestinal tract, traditionally explained by an acid-centric model in which gastric acid causes mucosal injury and symptoms. Proton pump inhibitors (PPIs) are the mainstay of therapy and effectively control symptoms in many patients. However, up to 50% of individuals remain symptomatic despite adequate acid suppression, suggesting that GERD is a multifactorial condition involving anti-reflux barrier dysfunction, impaired mucosal defense, immune activation, and alterations in the esophageal microbiota. This study is a narrative review aimed at evaluating current evidence on the interactions between acid suppression, esophageal microbial ecology, and host–microbe interactions in GERD, and at exploring the potential role of microbiota-targeted therapeutic strategies. The literature search was conducted using electronic databases (e.g., PubMed and Scopus), without formal time restrictions, prioritizing recent and clinically relevant studies. Evidence was qualitatively synthesized to provide an integrated overview. Recent studies suggest that the esophagus hosts a microbial ecosystem that may contribute to mucosal homeostasis. In GERD and Barrett’s esophagus, several studies report a shift toward Gram-negative anaerobic bacteria with potential pro-inflammatory activity. Long-term PPI therapy has been associated with increased gastric pH and changes in gastrointestinal microbiota composition, including a relative increase in taxa such as Streptococcus and Veillonella, and a reduction in short-chain fatty acid–producing bacteria. These alterations may be linked to dysbiosis and a possible increase in susceptibility to certain infections, although causality remains to be fully established. The main limitations of this review include its narrative design, the absence of systematic study selection, and the heterogeneity of the available evidence. Understanding the impact of acid suppression on microbial ecology may support the development of more integrated and personalized therapeutic strategies. Full article