摘要: The conversion of natural ecosystems to human land use is a primary cause of worldwide biodiversity loss and trophic structure changes in ecosystems. We investigated the effect of human land use at different spatial extents and aquatic trophic state on basal energy sources, food chain length (FCL), and the isotopic niche of apex fish in four large neotropical wetlands. We had two hypotheses. (i) Increased regional human land is negatively associated with the contributions of allochthonous energy sources, FCL, and isotopic niche. (ii) Trophic state is directly associated with FCL, autochthonous energy source, and niche area. We found that C3 riparian vegetation was the primary energy source for apex consumers. Human land uses in a 5000 m buffer were directly associated with allochthonous basal-energy source assimilation and niche area and indirectly with FCL. FCL was shorter in environments with more human land use and allochthonous energy source assimilation had an important role on FCL. Therefore, conserving riparian vegetation surrounding water bodies is a crucial protective factor for waters, as it serves as a primary energy source for food webs. Decreased FCL with increased human activity demonstrated the sensitivity of these environments to trophic-link losses from human invasion. Conversely, increased isotopic niche areas in environments with high human activities may be attributed to the introduction of new energy sources from those activities. Hence, the loss of natural cover resulting from human activities is an important factor in aquatic trophic structure changes.

摘要: Pharmaceuticals, including non-steroidal anti-inflammatory drugs (NSAIDs), such as indomethacin and ibuprofen, are prevalent pollutants in freshwater ecosystems, raising concerns about their ecological impact. While there is literature about pharmaceuticals in aquatic environments, the effects of both chemical and commercial forms of NSAIDs on aquatic organisms, particularly across generations, remain insufficiently explored. This study aims to bridge this gap by assessing the impact of pure and commercial forms of indomethacin, ibuprofen, and their mixture on Daphnia magna, a key freshwater species. Toxicity curves, enzyme activities, and metabolomics were used as endpoints to assess physiological responses to chronic and transgenerational exposures at an environmentally relevant concentration of 5 mu g/L. Results showed changes in the activities of beta-galactosidase and lipase, while a targeted LC-MS/MS approach revealed distinct metabolic fingerprints as a result of exposure for four generations to the chemical and commercial indomethacin and ibuprofen. Notably, exposure to chemical mixture of the two NSAIDs increased amino acids and biogenic amines, a trend also observed with commercial NSAIDs and their mixture, while the chemical NSAIDs did not have the same impact. This work emphasizes the necessity of ecotoxicological studies with transgenerational exposures as an approach to comprehend the effect of pharmaceutical stressors at low exposure concentrations, using molecular responses in physiology. This approach contributes to the broader mechanistic understanding of the ecological implications of these pharmaceuticals in freshwater ecosystems.

摘要: Large pelagic predatory fishes play an important role in marine ecosystems, occupying the highest position in food webs and accumulating energy and organic matter produced by aquatic organisms of lower trophic levels. Among pelagic predatory fishes, more attention has been given to the sharks, tunas and billfishes inhabiting equatorial and tropical waters, whereas pelagic predatory fishes inhabiting subarctic and temperate waters have been much less studied. We analyzed long-term midwater trawl survey data to investigate changes in the spatial distribution, ranges, and catch rates of the three most abundant large predatory teleosts in the Russian and adjacent waters of the northwestern Pacific, namely, the North Pacific daggertooth Anotopterus nikparini, the longnose lancetfish Alepisaurus ferox, and the Pacific pomfret Brama japonica. The northernmost distributions of daggertooth, lancetfish, and pomfret were observed in summer, spring, and autumn, respectively. All three species were characterized by the greatest northwards occurrence in the 2000s. In the study area, their maximum frequency of occurrence was recorded during the summer, and they were most frequently caught in the 1980s (lancetfish and pomfret) and 1990s (daggertooth). The average catch rates of daggertooth and pomfret were highest in summer, whereas those of lancetfish were highest in winter. The highest average catch rates of daggertooth, lancetfish, and pomfret were recorded in the 2000s, 1990s, and 1980s, respectively. The maximum absolute catch rates of lancetfish were recorded in winter, whereas those of daggertooth and pomfret were recorded in spring and summer, respectively. The maximum absolute catch rates of daggertooth and pomfret were observed in the 1980s, whereas those of lancetfish were observed in the 1990s.

摘要: Contamination by dexamethasone (DEX) in aquatic environments is expected to rise significantly as it is used in the treatment of inflammation, allergies, and autoimmune disorders, especially COVID-19. However, the underlying effects and mechanisms of DEX in leading to metabolic or infectious diseases have remained largely unexplored in teleosts. Here, we used zebrafish (Danio rerio) as a model to study the effects of DEX exposure on metabolic and infectious diseases. We found that DEX-induced hepatobiliary syndrome significantly increased susceptibility to type II grass carp reovirus (GCRV-II), which causes severe hemorrhagic disease in aquaculture. Comparative transcriptomic analysis demonstrated the shared and disease-specific immunometabolic responses among zebrafish larvae with hepatobiliary syndrome and/or GCRV-II infection. Moreover, compared with those of wild-type zebrafish, zebrafish larvae with DEX-induced hepatobiliary syndrome and/or GCRV-II infection presented increased expression of inflammatory markers (il1b), coagulation markers (fibrinogens and antithrombin III), and genes involved in autophagy, including hsp90aa. In vivo inhibition of autophagy via 3-MA and Hsp90 activity via geldanamycin markedly suppressed hepatic lipid deposition and reactive oxygen species accumulation caused by hepatobiliary syndrome and/or GCRV-II infection, thus significantly reducing the severity of disease and level of mortality induced by DEX and/or GCRV-II infection. In conclusion, our findings establish that the inhibition of autophagy and Hsp90 activity are promising therapeutic targets for DEX-induced hepatobiliary syndrome, GCRV-II infection, and DEX-induced hepatobiliary syndrome complicated with GCRV-II infection.

摘要: Dongting Lake is the second largest freshwater lake in China, supports high biodiversity and many endemic or endangered species, such as finless porpoise (Neophocaena phocaenoides), Baer's pochard (Aythya baeri), and east Asian minnow (Ochetobius elongatus), and is thus a global biodiversity hotspot. It is located within an important aquaculture and agricultural region, and many non-native species were introduced into the lake for aquaculture and the ornamental trade. However, information about these non-native species is scarce. We sampled the lake and updated a list of the lake's non-native species, reviewed their status, and threat to biodiversity, as well as their contribution to aquaculture and fisheries. A total of 157 non-native species, including 14 fishes, 136 vascular plants, 1 amphibian, 2 crustacea, 2 mollusca, and 2 reptile species have been imported into Dongting Lake. The main pathways of introduction are through the ornamental trade (97 species, 62%), followed by unintentional introductions (23 species, 15%), aquaculture (13 species, 8%), herbal medicine uses (8 species, 5%), forage grasses (7 species, 4%), food (5 species, 3%), timber (2 species, 1%) and biocontrol and oil (1 species each, 1% respectively). The non-native species origins are North America (43 species, 27%), South America (42 species, 27%), Asia (29 species, 18%), Europe (28 species, 18%), Africa (13 species, 8%), and Oceania (2 species, 1%). Some non-native species, such as red swamp crayfish (Procambarus clarkii), channel catfish (Ictalurus punctatus), and parrot's feather (Myriophyllum aquaticum), are valuable for aquaculture and horticulture. However, other nonnative species, such as Alternanthera philoxeroides, Pomacea canaliculate, and Trachemys scripta elegans, pose a potential threat to local biodiversity, human health, and sustainable development. Better management and control of non-native species in Dongting Lake are needed.

摘要: As nitrogen removal requires anaerobic conditions for denitrification, which facilitates the production of methane (CH4), a potent greenhouse gas, it is a challenge to achieve nitrogen removal with minimal CH4 emissions in constructed wetlands (CWs). This study proposed a solution for mitigating CH4 emissions while achieving nitrogen removal using porous fillers in CWs. We found that active denitrification occurred in the interior pores of these fillers in an oxygen-rich environment. The microbial analysis indicated that the internal pores of porous fillers created anaerobic habitats for denitrifiers as they had a higher nosZ/amoA ratio than on the surface. The anaerobic decomposition of organic matter was inhibited, yielding significantly lower CH4/CO2 ratios (<1.0 x 10(-5)) than those of traditional CWs (0.07). The methanogen proliferation and CH4 production efficiency also remained at low levels (<1.1 x 10(-3) and 0.045%, respectively), which was significantly lower than in traditional CWs (2.3 x 10(6) and 38%, respectively). Overall, this study proposed a strategy for mitigating the greenhouse effect of carbon emissions from CWs in the future.

摘要: Aquatic environments expose fishes to a wide range of pathogens, emphasizing the crucial role of their immune system. Chemokines are key mediators that bridge innate and adaptive immunity by regulating immune cell activity. As essential components of immune defense, immune cells play a central role in recognizing and eliminating pathogens. In mammals, chemokines exhibit direct antimicrobial activity and can enhance vaccine efficacy as molecular adjuvants. However, these functions remain insufficiently explored and summarized in teleost fishes, limiting their practical use in aquaculture. Given the evolutionary conservation of immune systems and chemokine families between teleost fishes and mammals, it is likely that chemokines have conserved functions across these vertebrates. This review systematically examines the roles of chemokines in regulating the functions of immune cells (macrophages, neutrophils, T cells, and B cells) in teleost fishes, and explores their potential application as direct antimicrobial agents and vaccine adjuvants in aquaculture, thereby providing a theoretical foundation for the prevention and control of aquatic diseases.

摘要: The glaciers on the Tibetan Plateau are important climate regulators and recharge sources for many rivers and lakes, which are of great ecological value. However, actions to protect glacier-associated habitats are urgent, as human activities have led to increased glacier retreat and may have an impact on climate and downstream environmental balance. Glaciers contain a variety of habitats (ice, snow, cryoconite, deglaciated soil, etc.) that harbor rich microbial communities (the main bearers of glacial life activities). To provide scientific support for the development of glacier protection strategies on the Tibetan Plateau from a microbial perspective, this review reveals the interactions between glacial microorganisms and glacial ecosystems on the Tibetan Plateau. In addition to describing the origin, diversity, adaptability and biogeochemical cycles of microorganisms, we emphasized the roles of environmental pollutants and climate change. It has been shown that exogenous microorganisms can be deposited on the glacier by atmospheric circulation. The special geo-climatic characteristics of glaciers may have prompted these microorganisms to adapt to this extreme environment through evolution and cooperation. These microorganisms are involved in the cycling of biogenic elements in glaciers, providing feedback to the Earth's ecosystem. However, increased environmental pollution may affect the glacier microorganisms. Some pollutants synergize with climate warming to accelerate glacial melting, with meltwater carrying microorganisms, nutrients, and pollutants into downstream ecosystems, which may have far-reaching impacts on downstream ecosystems and the global climate. Reducing source pollution, strengthening international cooperation, implementing long-term monitoring, developing predictive models, and tapping into special microorganisms are the way forward in guarding the clean land of the Tibetan Plateau glaciers in the future.

摘要: Grass carp reovirus (GCRV)-induced gene 1 (Gig1) is identified initially in crucian carp C. auratus as a novel interferon-stimulated gene (ISG) encoding an antiviral protein and subsequently as the founder member of Gig1 gene family. However, the evolution and function of Gig1 family members remain largely unknown. In this study, genome-wide searchs of 100 vertebrate species representing the main taxonomic lineages revealed that the Gig1 family originated from a common ancestor of bony fish but was completely lost in tetrapods. The Gig1 family is divided into three subfamilies, each with its own characteristics in gain and loss. Compared to subfamily I that originated the earliest and showed no significant change in gene copies, subfamilies II and III were expanded robustly with teleost radiation. Despite no known domains having been identified, motif prediction revealed a conserved motif arrangement in all Gig1 family proteins. Functionally, both zebrafish and grass carp have subfamilies I and II but not subfamily III. However, only certain subfamily II genes were highly induced by viral infection and thus capable of inhibiting viral replication by overexpression and knockout assays. The Japanese rice fish medaka has no subfamily II and, strikingly, one subfamily III gene acquired antiviral feature. Site-directed mutation showed that three leucine residues conserved in the motif 1 were essential for the antiviral role of subfamily II genes in zebrafish. In summary, our results indicate that bony fish-specific Gig1 gene family has been undergoing diversification in expression and function toward virus infection in a given species.

摘要: Marine microplastics (MPs) are an increasingly important concern worldwide. This study aimed to investigate the occurrence and characteristics of microplastics in an intertidal sea snail, the common periwinkle (Littorina littorea) sampled from Saint Martin's Island, Bay of Bengal. The results revealed that 100% of the common periwinkle snails ingested microplastics (MPs), with a mean abundance ranging from 2.63 +/- 1.07 to 23.89 +/- 3.53 MP/g (average: 7.76 +/- 5.77 MP/g). Microplastic particles in the 100-1500 mu m size class were the most abundant (63%), whereas black and red fibers were the most abundant colors and shapes. Polypropylene (PP, 34%) and polyethylene (PE, 38%) were the major polymer types, followed by polystyrene (PS, 15%) and polyethylene terephthalate (PET, 13%). Although the polymer hazard index (PHI) showed risk categories III to IV due to highly hazardous polymers such as PS and PE in the soft tissue of the common periwinkle snails, the pollution load index (PLI <10) revealed minor contamination across the sampling site of Saint Martin's Island. Gastropod feeding patterns and food items impacted MP abundance in the studied area.