Search Results (235)

The gut microbiota plays an essential role in the host’s metabolism. Its composition and structure depend on biological and environmental factors. This work was designed to identify the composition and structure of the wild and captive red grouper (Epinephelus morio) microbiota and make predictions regarding its metabolic functions. Our hypothesis stated that wild and captive individuals would share the most abundant taxonomic groups, forming a core microbiota, and individuals in captivity might have exclusive taxonomic groups. Metagenomic DNA was extracted from the intestinal contents of wild and captive individuals. The 16S rRNA gene was amplified and sequenced using Illumina pair-end technology. QIIME2 pipeline was used for sequence analysis and alpha and beta diversity assessment. PICRUSt was used to infer metabolic functions. Twenty-nine phyla were identified; the most abundant were Pseudomonadota, Bacillota, Fusobacteriota, and Actinomycetota. The dominant genera were Photobacterium, Vibrio, Cetobacterium, and Escherichia-Shigella. The metabolic prediction analysis suggested that the Epinephelus morio gut microbiota is related to food digestion, the immune system, antioxidant enzymes, antibiotic resistance, and vitamin B12 transport. We concluded that the microbiota of E. morio established in captivity is sensitive to environmental changes such as water pollution, which can cause a decrease in diversity. Full article

Cadmium (Cd) pollution poses a serious threat to freshwater ecosystems. The freshwater mussel Anodonta woodiana is increasingly used as a bioindicator for monitoring Cd pollution in aquatic environments. However, the primary routes of Cd accumulation in A. woodiana remain unclear, and the molecular regulatory mechanisms underlying Cd accumulation are poorly understood. To address these gaps, this study employed a novel stable isotope dual-tracer technique to trace Cd from water (waterborne ¹¹²Cd) and the green alga Chlorella vulgaris (dietary ¹¹³Cd) during the simultaneous exposure experiment. Comparative transcriptomic analysis was then conducted to characterize molecular responses in A. woodiana following Cd exposure. The results showed that although newly accumulated ¹¹²Cd and ¹¹³Cd increased with exposure concentration and duration, the relative importance of ¹¹²Cd (91.6 ± 2.8%) was significantly higher than that of ¹¹³Cd (8.4 ± 2.8%) (p < 0.05). Cd exposure induced differentially expressed genes primarily enriched in the metabolic processes, cellular processes, and/or the ubiquitin-mediated proteolysis pathway. Within the ubiquitin-mediated proteolysis pathway, TRIP12 (E3 ubiquitin-protein ligase TRIP12) and Cul5 (cullin-5) were significantly upregulated. The findings will provide critical insights for interpreting Cd biomonitoring data in freshwater environments using mussels as bioindicators. Full article

Perfluorooctanoic acid (PFOA) and its replacement, GenX, are per- and polyfluoroalkyl substances (PFASs) widely used in industrial and consumer applications. Pregnant women are a vulnerable population to environmental pollutants. The maternal effects of GenX and PFOA exposure during pregnancy have not been fully elucidated. In this study, pregnant mice received daily oral doses of GenX (2 mg/kg/day), PFOA (1 mg/kg/day), or Milli-Q water (control) throughout gestation. Histopathological analyses revealed significant liver abnormalities in both exposure groups, including hepatocyte swelling, cellular disarray, eosinophilic degeneration, karyopyknosis, lipid vacuolation, and increased inflammatory responses. Through transcriptomics analyses, it was found that multiple metabolic and inflammatory pathways were enriched in both exposure groups. In the GenX group, overexpression of CYP4A, c-Myc, and Oatp2 proteins and decreased expression of EGFR and β-catenin in the liver suggested disruption of lipid and bile acid metabolism. In the PFOA group, significantly upregulated protein levels of NLRP3, GSDMD, caspase-1, IL-18, and IL-1β indicated hepatic pyroptosis. Despite these distinct pathways, both compounds triggered inflammatory cytokine release in the liver, consistent with the results of the transcriptomics analysis, suggesting shared mechanisms of inflammatory liver injury. Taken together, our findings provided novel insights into the hepatotoxicity mechanisms of GenX and PFOA exposure during pregnancy, underscoring the potential health risks associated with PFAS exposure. Full article

Global warming raises surface water temperatures, impacting fish alongside pollutants, such as ubiquitous xenoestrogens. Combined stressor effects are poorly studied but likely to worsen impacts and hinder biota adaptation, warranting further research. Unadapted fish face heightened risks. The liver is a vital metabolic organ, sensitive to temperature and xenoestrogens, eventually adjusting hepatocyte size and number to ensure survival, growth, and reproduction. This study assessed, for the first time, the impact of exposure (45 days) to thermal stress (29 °C versus 26 °C) and ethinylestradiol (EE2, 5 ng/L) on male guppies, primarily on body and quantitative liver morphology. Higher temperature reduced body mass (14%) and standard length (3.6%) gain. EE2 exposure reduced body mass increase (14%), hepatosomatic index (20%), and the volumes of the liver (32%), hepatocytes (16%), and their nuclei (17%). The nucleus-to-cytoplasm ratio and total hepatocyte number remained stable. No histopathological lesions existed. Guppies appear to have adapted to stressors by reducing hepatocyte size and utilizing lipid reserves, yet they exhibited deficits in body growth and hepatosomatic index. Gonadal maturation was unaffected. Only under EE2 at 29 °C did hepatocytes show minimal lipid droplet content (less vacuolation). This indicated exhausted reserves, reinforcing how heat and toxicants interact to exacerbate impacts. Full article

The presence of recalcitrant organic compounds in oilfield-produced-water poses significant challenges for conventional biological treatment technologies. In this study, an Fe³⁺-augmented composite bioreactor was developed to enhance the multi-pollutant removal performance and to elucidate the associated microbial community dynamics. The Fe³⁺-augmented system achieved efficient removal of oil (99.18 ± 0.91%), suspended solids (65.81 ± 17.55%), chemical oxygen demand (48.63 ± 15.15%), and polymers (57.72 ± 14.87%). The anaerobic compartment served as the core biotreatment unit, playing a pivotal role in microbial pollutant degradation. High-throughput sequencing indicated that Fe³⁺ supplementation strengthened syntrophic interactions between iron-reducing bacteria (Trichococcus and Bacillus) and methanogenic archaea (Methanobacterium and Methanomethylovorans), thereby facilitating the biodegradation of long-chain hydrocarbons (e.g., eicosane and nonadecane). Further metabolic function analysis identified long-chain-fatty-acid CoA ligase (EC 6.2.1.3) as a key enzyme mediating the interplay between hydrocarbon degradation and nitrogen cycling. This study elucidated the ecological mechanisms governing Fe³⁺-mediated multi-pollutant removal in a composite bioreactor and highlighted the potential of this approach for efficient, sustainable, and adaptable management of produced water in the petroleum industry. Full article

Nitrogen-metabolizing microbes are the keystone drivers of reducing nitrogen pollutants in wastewater and natural waters, but the one-way experiment with fixed screening factors fails to discover the optimal scope of nitrogen-metabolizing microbes performing nitrogen reduction. This study novelly combines the one-way experiment and response surface methodology (RSM) modeling to synthesize an effective nitrogen reduction microbial community, with the RSM model showing high goodness-of-fit (R² = 0.83, p = 0.01) for optimizing the strain combination. Eight bacterial strains were isolated from contaminated sediment and activated sludge. Three efficient strains, arranged to Ignatzschieria indica, Staphylococcus epidermidis, and Acinetobacter baumannii by 16S rDNA sequencing, were screened using the above combination method to synthesize a nitrogen reduction microbial community. Within the synthetic microbial community, Ignatzschieria indica and Staphylococcus epidermidis possessed denitrification abilities, and Acinetobacter baumannii contributed to nitrification with 99% of ammonium oxidation. This synthesis microbial community displayed synchronous nitrification and denitrification under interval aeration and possessed wide pH tolerance from 6 to 10, with a steady >80% total inorganic nitrogen reduction. This research managed to synthesize a tolerant nitrogen reduction microbial community and provides novel insight for constructing synthetic microbial consortia. Full article

Aquatic pollution in the Bay of Bengal has become a major environmental issue with long-term impacts on fisheries, biodiversity, and ecosystems. The review paper examines the major pathways, sources, and ecological consequences of aquatic pollution in the Bay of Bengal. Pollutants such as heavy metals, pesticides, petroleum hydrocarbons, and microplastics have been reported at concerning levels in the soil and water in aquatic ecosystems. Rivers act as key routes, transporting pollutants from inland sources to the Bay of Bengal. These contaminants disrupt metabolic and physiological functions in fish and other aquatic species and pose serious threats to food safety and public health through bioaccumulation. Harmful algal blooms (HABs), caused by nutrient enrichment, further exacerbate ecosystem degradation in the Bay of Bengal. The review highlights the immediate need for strengthened pollution control regulations, real-time water quality monitoring, sustainable farming practices, and community-based policy interventions to preserve biodiversity and safeguard fisheries. Full article

In coastal waters, tributyltin chloride (TBTC), a persistent organic pollutant, is extensively present. It is uncertain, therefore, if exposure to TBTC can harm haarders and how. This study exposed the fish for 60 days in order to investigate the molecular mechanism of haarder following TBTC poisoning. Our findings demonstrated that growth indices dropped, liver tissue was damaged, and the liver’s total tin concentration rose following TBTC exposure. Furthermore, we discovered that blood reactive oxygen species rose while total blood cell count decreased. As malondialdehyde levels rose, total antioxidant capacity and antioxidant enzyme activity (superoxide dismutase, catalase, and glutathione peroxidase) were markedly reduced. After being exposed to TBTC, liver cells displayed clear signs of apoptosis. Differentially expressed genes were primarily linked to oxidative stress, energy metabolism, and apoptosis, according to the transcriptome study of livers. Overall, the long-term stress of TBTC resulted in the antioxidant system being harmed, as well as serious malfunction of the energy metabolism and apoptotic response. Full article

Most large-scale crude oil spills occur in marine environments. We screened easily propagable/maintainable halophiles to develop agents for the bioremediation of marine spills. A bacterial strain isolated from a polluted region of the Great Salt Lake was characterized and tested for its ability to degrade crude oil. The strain (Salinivibrio costicola) is motile, catalase- and lipase-positive, a facultative anaerobe, and an obligate halophile. Its growth optimum and tolerance ranges are: NaCl (5%, 1.25–10%), pH (8, 6–10), and temperature (22 °C, 4–45 °C). Its genome (3,166,267 bp) consists of two circular chromosomes and a plasmid, containing 3197 genes, including some genes potentially relevant to hydrocarbon metabolism. The strain forms a biofilm but is considered nonpathogenic and is sensitive to some common antibiotics. Lytic bacteriophages infecting the strain are rare in the water samples we tested. The strain survived on desiccated agar media at room temperature for a year, grew optimally in complex media containing 0.1–1% crude oil, but failed to reduce total recoverable petroleum hydrocarbons from crude oil. Thus, a recalcitrant halophile may endure crude oil without mineralizing. Due to some of their advantageous attributes, such strains can be considered for genetic manipulation to develop improved agents for bioremediation. Full article

In recent years, tires have become a prominent concern for researchers and environmentalists in regard to their potential threat of tire-derived pollutants (TDPs) to human health. Among these pollutants, N-(1,3-dimethylbutyl)-N′-phenyl-p-phenylenediamine (6PPD) and its oxidized form, 6PPD-quinone (6PPD-Q), have been of primary interest due their ubiquity in urban environments, and their potential negative effects on human health. This review provides a summary of human health implications of TDPs, including 6PPD and 6PPD-Q. For the methodology, datasets were collected from the literature sources, including sources, formations and ecological effects of these pollutants, and pathways of human exposure and public health significance. Urban soils are key for services including carbon storage, water filtration, and nutrient cycling, underpinning urban ecosystem resilience. Soil degradation through compaction, sealing, and pollution, particularly by pollutants from tire wear, destroys these functions, however. These pollutants disturb the soil microbial communities, leading to a loss of diversity, an increase in pathogenic species, and changes in metabolism, which in turn can impact human health by increasing disease transmission and diseases of the respiratory systems. Incorporating green-infrastructure practices can enhance the ecosystem service potentials of urban soils and contribute to sustainable, climate-resilient urban city development. These findings underscore the pressing need for a coordinated international campaign to study chronic health effects and science informed policy frameworks to address this ubiquitous environmental health concern—an issue that crosses urban water quality, environmental justice, and global management of tire pollution. Full article

Microcystin-leucine arginine (MC-LR) is a prominent water pollutant known for its potent hepatic toxicity. However, the effects of subchronic exposure to environmentally relevant concentrations of MC-LR on the fish liver remain poorly understood. This study aimed to systematically evaluate the impact of subchronic MC-LR exposure on the liver of darkbarbel catfish (Tachysurus vachelli). A total of 270 one-year-old fish were exposed to MC-LR (0, 2, and 5 μg/L) for 28 days and sampled on days 14 (D14) and 28 (D28). Histopathological analysis revealed marked hepatic inflammation in the MC-LR treatment groups, manifested as cellular degeneration, hyperemia, and inflammation. MC-LR exposure induced oxidative stress, evidenced by elevated malondialdehyde (MDA) levels and compensatory upregulation of superoxide dismutase (SOD) activity on D28. While hepatic lipid profiles were not altered by low-dose MC-LR, significant elevation of low-density lipoprotein cholesterol (LDL-C) specifically on D28 indicated incipient lipid metabolic disorder. Metabolomic analysis demonstrated a higher sensitivity, highlighting the stress response of the liver to low-dose MC-LR exposure. The results suggest MC-LR exposure disrupted hepatic phosphatidylcholine (PC) biosynthesis and inhibited lipoprotein formation, thereby impairing lipid transport and contributing to lipid metabolic disorders. In summary, subchronic exposure to environmentally relevant concentrations of MC-LR-induced hepatic tissue inflammation, oxidative stress, and lipid metabolic disorders in darkbarbel catfish. Full article

This work describes the application of three different AgBr heterojunctions with TiO₂, SnO₂ and WO₃ in the treatment of two water sources: wastewater from a dairy industry facility (WDI) and water from a polluted river (WPR). All heterojunctions were widely characterised, and it was observed that the physicochemical properties of all the coupled materials were similar; however, the highest elimination of Enterobacteriaceae (>90%) was obtained with the AgBr/WO₃(20%) photocatalyst in WDI. Under the same conditions, with this photocatalyst, the complete removal of bacteria (i.e., E. coli, total coliforms and other Enterobacteriaceae) was achieved in WPR. The chlorides, hardness and colour in the two water samples decreased after photocatalytic treatment with all the coupled materials. However, nitrate levels and chemical oxygen demand increased due to the possible formation of intermediary species from the photodegradation of organic pollutants and the release of metabolic intermediates from bacterial degradation during the photocatalytic process. Overall, heterogeneous photocatalysis based on AgBr-coupled materials shows potential as a tertiary treatment for WDI and for the purification of vegetable irrigation water. However, it is still important to consider the need to optimise the integrity of photocatalytic materials in order to maintain their bactericidal effectiveness through continuous reuse. Full article

Microplastics (MPs) and heavy metals are commonly present in soil at significant concentrations and can interact in complex ways that pose serious threats to environmental and ecological systems. The effects of combined contamination by different types of heavy metals and microplastics on plants, as well as on soil microbial communities and their functions, remain largely unexplored. In this study, a series of pot experiments was conducted to investigate the effects of composite contamination involving two heavy metals (Cd and Pb) and two types of microplastics polylactic acid (PLA) and polybutylene succinate (PBS) at varying concentrations (0.1% and 0.5%, w/w). The impacts on water spinach (Ipomoea aquatica) growth and heavy metal accumulation were evaluated, and the rhizosphere bacterial and fungal community structure and diversity were analyzed using high-throughput sequencing. The presence of Cd, Pb, and microplastics significantly inhibited the growth of water spinach, reducing both its length and biomass. Under combined microplastic–heavy metal contamination, phytotoxicity increased with rising concentrations of PLA and PBS. Microplastics were found to alter the mobility and availability of heavy metals, thereby reducing their accumulation in plant tissues and decreasing the levels of available potassium and phosphorus in the soil. Furthermore, microplastic–heavy metal interactions significantly influenced the composition and diversity of soil microbial communities, leading to an increased abundance of heavy-metal-tolerant and potential plastic-degrading microorganisms. A strong correlation was observed between microbial community structure (both bacterial and fungal), soil physicochemical properties, and plant growth. Functional predictions using PICRUSt2 suggested that the type and concentration of microplastics significantly affected rhizosphere microorganisms’ metabolic functions. In conclusion, the present study demonstrates that combined microplastic and heavy metal contamination exerts a detrimental effect on soil nutrient availability, resulting in alterations to soil microbial community composition and function. Furthermore, this study shows that these contaminants can inhibit plant growth and heavy metal uptake. The findings provide a valuable contribution to the existing body of knowledge on the ecotoxicological impacts of microplastic–heavy metal composite pollution in terrestrial ecosystems. Full article

Heavy metal pollution, particularly cadmium (Cd) contamination in water and farmland, might accumulate in natural insect enemies through the food chain. In response to this heavy metal stress, natural enemy insects adapt by altering their metabolism and behaviors. As a result, this investigation aimed to elucidate how the development, reproduction, and feeding of Harmonia axyridis Pallas (Coleoptera: Coccinellidae) are affected under Cd contamination. Compared to the control group, the developmental period of H. axyridis was prolonged, with decreased survival, predation, and body weights. Notably, adult insects exhibited deformation, including molting difficulties and wing deformities, which indicated reduced fitness. The ovarian development of female insects was delayed with reduced size, and the pre-oviposition period was prolonged under Cd contamination. Additionally, the hatching rate of offspring was significantly reduced. The Vitellogenin 1 (Vg1) and Vitellogenin 2 (Vg2) exhibited considerable changes throughout their developmental stages. Our results confirmed that the accumulation of Cd has a significant impact on the growth, development, and normal molting of H. axyridis, affecting the reproduction of H. axyridis. The aforementioned results provide valuable insights into the potential ecological effects of Cd accumulation on the food chain, which can inform strategies for pest control, ecosystem stabilization in rice fields, and potentially novel bioremediation approaches. Thereby establishing a theoretical foundation for pest control and ecosystem stabilization in rice fields under Cd contamination while simultaneously providing novel insights for bioremediation strategies. Full article

Microplastics (MPs) and nanoplastics (NPs), formed through the degradation of larger plastic materials, are emerging pollutants of significant concern. While their impact on aquatic ecosystems is well documented, their effects on terrestrial, especially farm animals remain underexplored. This review assesses the potential threats of MPs and NPs to Bangladesh’s livestock sector by analyzing the results of experimental models and environmental studies. In Bangladesh, MPs and NPs have been detected in agricultural soils, air, water bodies, and aquatic organisms, indicating possible entry into animal systems through contaminated feed, water, and inhalation. Once internalized, these particles may trigger oxidative stress, inflammation, and tissue damage, impairing vital biological systems. Documented health consequences include reduced fertility, hematotoxicity, gut microbiota imbalance, gut–brain axis disruption, skeletal disorders, and metabolic dysfunction. Additionally, MPs and NPs can induce genomic changes, including altered gene expression and DNA hypomethylation, intensifying physiological damage and reducing productivity. Therefore, managing plastic contamination is vital in protecting animal health, ensuring food safety, and preserving human well-being around the globe, especially in vulnerable regions like Bangladesh. Given the critical role of livestock and poultry in ensuring food security and public health, the findings highlight an urgent need for comprehensive research and mitigation strategies. Full article