摘要: Schizothoracine fishes are distributed in the Nagqu region, which is the hinterland of the Tibetan Plateau. They have adapted to the cold and strongly ultraviolet environment of the plateau and show diverse morphologies, which makes them ideal for studying the relationship between phenotype and environment. However, traditional morphological measurements are time consuming and labor costly. In this study, we propose a deep-learning-based method for acquiring high-throughput phenotypic data of fishes, including image dataset construction of schizothoracine fishes (including front, side, and top views), fish keypoint detection based on the You Only Look Once (YOLO) model, and reconstruction of 2D and 3D keypoint coordinates based on multiple views. A total of 7050 phenotypic data points consisting of keypoint distances and angles were constructed for each fish and were highly correlated (>0.98) with the corresponding data measured manually. We obtained phenotypic data for a total of 525 fishes from three schizothoracine fish groups inhabiting riverine, lacustrine, and river-lake transitional environments using the proposed phenotypic data acquisition method. We employed a random forest algorithm to classify the groups, achieving a classification accuracy of 96%, and identified 15 morphometric indices that exhibited statistically significant differences., of which 6 were related to head morphology, 6 related to body shape, and 3 related to tail morphology, based on the random forest algorithm. Specifically, river-living schizothoracine fishes showed a blunt head, robust body, and elongated caudal peduncle which may reflect adaptations to the turbulence of the river, while the lake-living schizothoracine fishes have the opposite effect. Schizothoracine fishes at the river-lake transitional zones were phenotypically characterized as being in the middle of the two phenotypes, and these presumably reflect adaptations to their lake habitat. This study provides a methodological reference for obtaining high-throughput phenotypic data on fish and a theoretical basis for understanding the adaptation of very high-altitude schizothoracine fishes to their environment.

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摘要: Autophagosome generation, development and maturation are largely dependent on Atg9a, an important member of the autophagy-related protein family. However, the potential role of fish Atg9a in viral infections is poorly understood. This research involved cloning and characterizing an Atg9a homologue from the orange-spotted grouper (Epinephelus coioides), known as EcAtg9a. The ORF (open reading frame) of EcAtg9a is composed of 2583 nucleotides and encodes 860 amino acids. EcAtg9a was detected in every tissue that was analyzed, and was particularly abundant in liver, kidney, head and blood. EcAtg9a expression levels in grouper spleen (GS) cells increased following infection with SGIV and RGNNV. EcAtg9a was uniformly present in the cytoplasm, while found to co-exist with the endoplasmic reticulum (ER), Golgi apparatus, mitochondria and lysosomes. EcAtg9a suppressed the expression of interferon-related genes and factors linked to inflammation while promoting the replication of SGIV as well as RGNNV in GS cells. In addition, EcAtg9a could interact with the key molecules of the cGAS-STING pathway including EccGAS, EcTBK1, EcSTING, and even EcIRF3. EcAtg9a facilitated the upregulation of Beclin1 and LC3-II synthesis within cells, resulting in an augmented formation of LC3 fluorescent aggregates. The level of eIF2 alpha phosphorylation (S51) was increased in EcAtg9a-overexpressing cells, and the p53 protein moved from the cytoplasm into the nucleus. Findings may offer insight into how grouper's innate immunity works against viral infections.

摘要: Biologging is a method that utilizes animal-borne devices to study the behavioural ecology, physiology, and surrounding environment of animals. This is the Lagrangian observation method, which assigns a coordinate system origin to each animal, making the biologging unique among observation platforms. This study reviews biologging as a new tool for understanding the ocean by combining other observation methods, and proposes strategies for applying biologging technology to address various marine issues through relevant policies. Attempts to resolve marine issues using biologging are described, including ocean warming, weather forecasting, marine debris, marine chemical pollution, anthropogenic noise, preservation of marine protected areas, bycatch from fisheries, and anthropogenic disturbance of habitats used by marine top predators. While biologging alone is insufficient to resolve marine issues, it can complement other Lagrangian platforms such as drifting buoys and Eulerian remote sensing, enhancing the predictive accuracy of models, and filling existing gaps in knowledge. The Internet of Animals (IoA), which is a derivative concept of the Internet of Things (IoT), will be a future solution that collects a range of data from inaccessible ocean from animals equipped with devices through a network, making open data access crucial. Conclusively, we present research examples and potential methods involving biologging that will guide the formulation of sustainable ocean management policies.

摘要: Aquaculture, as a major source of protein in the food industry, heavily relies on the introduction and farming of non-native species. Pikeperch, Sander lucioperca, an important fish in aquaculture, poses a threat to the survival of native species because it is a piscivore and has been introduced globally. To address this issue, we examined the niche dynamics of invasive populations by comparing the climatic niches of native and invasive populations of Pikeperch. Predictive models based on global occurrence data were used to assess the distribution areas of native and invasive populations, and the model results were converted into area measurements to estimate the potential invasion risk of pikeperch. The results show that invasive populations, especially those in Asia, occupy broader climatic niches. The main difference is that, compared to native-range populations, non-natives occupy warmer and more humid regions. These climatic differences have led to niche expansion by invasive populations, with invasive populations (particularly in Asia) showing a greater potential for invasion. we applied niche modeling to evaluate the potential invasion risks associated with introducing different geographic populations. Our models provide a scientific basis for managing aquaculture introductions, aiming to reduce invasion risks and minimiz both ecological and economic impacts.

摘要: Aggregation is suggested beneficial with foraging, defense, and other fitness for the group members. While long distance dispersal with kinship has been found in several marine fishes, similar cases have not been reported in inland waters. We utilized microsatellite genotype data of 397 eggs or juvenile silver carp (Hypophthalmichthys molitrix) born in 2017 from the middle and lower reaches of the Yangtze River in China to analyze their relatedness and infer the dispersal patterns during their early life stages and whether they dispersed with their kinship. There were 11-58 pairs of full siblings or half siblings between samples from the spawning ground (Yichang section) and other sites (34.1-1047.2 km) which showed the dispersal path. Particularly, the proportion of maternal siblings (mean: 47.9%) was higher than random, indicating kinship aggregation, or that the fish traveled with their kinship during their early life stages. Such kin aggregation has profound implications for our understanding of early life stage dispersal in inland water fish populations. Our findings suggest that the preservation of habitats along the middle Yangtze River should be increased. In particular, the channelized river bank should be rebuilt with more heterogeneous habitat, and the lake-river connections should be restored to expand the amount of appropriate habitat.

摘要: Recent cold waves and abrupt seasonal temperature drops have significantly impacted aquaculture, slowing fish growth and causing mass mortality. The intestine plays a crucial role in digestion, nutrient absorption, metabolism, and physiological regulation. However, studies on the molecular mechanisms of fish intestinal response to low-temperature stress and methods to mitigate damage are limited. This study investigated the intestinal response of Danio rerio to low temperatures with three groups: a control group at 28 degrees C (CT28), a cryogenic group at 18 degrees C (ST18), and an extreme cryogenic group at 10 degrees C (LT10), with time points of 0, 12, 24, and 48 h. Results showed significant structural changes in the 18 degrees C group, with inflammatory infiltration starting at 24 h. Damage worsened in the 10 degrees C group, showing severe inflammation. Tunel staining revealed increased cell apoptosis with lower temperatures and longer exposure, peaking at 10 degrees C and 48 h following exposure (p < 0.05). Alcian blue periodic acid-schiff stain revealed that lower temperatures promote an increase in the number of goblet cells. Metabolomics analysis compared intestinal metabolites between CT28 vs. ST18 and CT28 vs. LT10. Fifty-three metabolites were shared between the CT28_ST18 and CT28_LT10 groups in positive ion mode, and 16 in negative mode, with 22 and 9 metabolites showing linear changes. These 31 metabolites could serve as potential indicators for low-temperature stress in D. rerio. Specifically, eight metabolites from the lysophosphatidylcholine (LPC) group increased significantly, while antioxidant alanylglutamine (AGD) decreased. Supplementing the diet with 0.5% AGD reduced intestinal damage, and 1.0% AGD improved low-temperature tolerance. This study provides new insights into the molecular mechanisms of fish response to cold stress and lays the foundation for future research.

摘要: Butyric acid and its derivatives are widely applied in aquaculture as an alternative to antibiotics, which are beneficial for the growth and health of aquatic animals. However, these products have some disadvantages including poor stability, a bitter taste, and low bioavailability. In this study, a novel butyric acid, namely pentabutyryl glucose ester (PGE), was synthesized, and the effects of PGE on the growth, liver and intestinal health, and gut microbiota of zebrafish were evaluated. We found that the supplementation of PGE at a level of 0.05% promoted the growth performance of zebrafish, decreased the level of serum LPS, ALT, and AST, and improved liver health. The expression levels of pro-inflammatory factors (NF-kappa B p65 and IL-6) were notably downregulated, while those of anti-inflammatory factors (TGF-beta and IL-10) were upregulated, in the intestines of zebrafish fed 0.05% PGE compared with the control group. Additionally, inclusion of PGE in the diet of zebrafish increased the relative abundance of probiotic bacteria such as Bacillus and Lentilactobacillus. Overall, this study demonstrated that PGE is beneficial for the growth, liver and intestinal health, and the gut microbiota of zebrafish, providing a novel pathway to improve the application of butyric acid as a feed additive in aquaculture.

摘要: Freshwater ecosystems are threatened by flow regulation, sedimentation, habitat degradation, non-native species, and water pollution. These disturbances have led to global losses of biodiversity and habitats. Therefore, it is essential to evaluate the ecological condition of freshwater ecosystems to promote effective management practices. Quantitative predictive models based on multivariate analyses of taxa richness are recognized ecological tools that can facilitate the monitoring and managing of freshwater ecosystems worldwide. However, few studies have used this approach to assess tropical rivers and streams. By evaluating predictive models, we can assess their usefulness for determining water-body taxonomic richness. We built a RIVPACS-type model based on macroinvertebrate assemblages (MINASPACS), for spatially extensive taxa richness assessments of Minas Gerais state streams, southeast Brazil. As a second objective, we assessed the sensitivity of the MINASPACS to human-induced disturbances affecting Minas Gerais streams through the relative risk (RR) approach. The MINASPACS model was trained with biological and environmental data from 78 reference sites and showed good accuracy (R-2> 0.6, SD O/E 1/4 0.16). We found that percent of urban infrastructure, percent of catchment anthropogenic land use, Turbidity, Total Nitrogen, and Total Phosphorus represented significant risks to the taxa richness of Minas Gerais streams. Because of its accuracy, sensitivity, and use of map-level predictor variables, our model provides a clear, simple, and defensible measure of stream macroinvertebrate taxa richness across diverse biomes.

摘要: The use of environmental DNA (eDNA) has significantly revolutionized studies in biodiversity science. A crucial innovation of eDNA-based biodiversity assessment is the ability to detect species through genetic materials released by organisms into their environments, without the need for direct observation or capture (i.e., organisms remain unseen). The fact that organisms remain unseen has many pros and cons, many of which have been largely recognized and technically addressed or managed. However, two recent studies have both highlighted another critical issue regarding eDNA-based biodiversity assessments: the prevalence of overlooked eDNA contamination originating from human activities, such as the release of treated wastewater into aquatic ecosystems. Such eDNA contamination derived from human activities can lead to significant false positive errors in eDNA-based biodiversity assessments, particularly in human-disturbed ecosystems such as urban and coastal environments. Here I discuss the causes and consequences of eDNA contamination, stressing that this widespread but often neglected issue can substantially affect both eDNA-based theoretical studies and applied biodiversity management. Additionally, I propose several potential technical solutions to minimize its negative impacts, including well-designed sampling strategies, a deeper understanding of eDNA persistence and its spread in local waterbodies, and the use of environmental RNA (eRNA). Given that eDNA contamination can significantly impact ecosystems such as urban and coastal environments where biodiversity provides essential ecosystem services, I call for precautionary approaches and technical efforts to mitigate false positives derived from eDNA contamination in biodiversity assessments in these ecosystems.