摘要: Under the impact of global climate change and anthropogenic activities, the global distribution of toxigenic microalgae and phycotoxins is expanding, potentially affecting the growth and development of marine organisms, threatening the development of marine aquaculture and human health. Paralytic shellfish toxins (PSTs) are a group of highly potent neurotoxic phycotoxins that are widely distributed worldwide and paid attention to by scientists because of their toxicity. In this paper, the toxicological effects and mechanisms of PSTs-producing microalgae and PSTs on aquatic biota, such as shellfish, fish, and zooplankton were comprehensively reviewed. PSTs-producing microalgae and PSTs can exert multiple toxicological effects on aquatic organisms including affecting locomotion, swimming and feeding behavior, causing cellular structure and DNA damage and apoptosis, disrupting the immune system, decreasing fertilization and hatching rates, affecting embryonic development, and lead to larval developmental abnormalities. In summary, PSTs can cause neurotoxicity, developmental toxicity, cytotoxicity and immunotoxicity to organisms that are intoxicated by them. This review consolidates our understanding of the toxicological effects of PSTs on marine biota, and provides a reference for the safe risk management of toxigenic microalgae and phycotoxins, for more sustainable development of the mariculture industry and the protection of human health.

摘要: Sex-specific differences in disease resistance are well-documented in vertebrates, with immune responses often influenced by sex hormones and other physiological factors. However, the relationship between gut microbiota and immunity in driving these differences is not fully understood, particularly in non-mammalian vertebrates such as teleost fish. This study explores the role of sexual dimorphism in gut immunity and microbiota dynamics in juvenile common carp (Cyprinus carpio) following infection with the spring viremia of carp virus (SVCV). Using transcriptomic analysis and 16S rRNA sequencing, we assessed gut microbiota and immune responses in male, female, and all-female carps. Females exhibited heightened antiviral and inflammatory responses, which were associated with significant bacterial translocation and microbial dysbiosis. In contrast, males showed greater disease resistance and maintained a more stable gut microbiota. These results emphasize a significant correlation between changes in gut microbiota and sex-specific immune responses and provide valuable insights into the mechanisms underlying immunological dimorphism in teleost fish. These findings have important implications for improving aquaculture management and developing targeted disease control strategies.

摘要: The determinants of local differences in species and functions matter for reservoir management but have seldom been investigated. To this aim, we explored fish taxonomic, and functional beta diversity between local assemblages in a large Chinese reservoir. Taxonomic β diversity was primarily driven by species richness differences (54%–72%), while functional β diversity was almost equally driven by turnover and nestedness components. Environmental characteristics of the sites were significant predictors of all facets of fish β diversity. Additionally, site contributions to taxonomic (LCBD) and functional (XLCBD) β diversity were significantly associated with human activity variables, suggesting that there is a pressing need to mitigate human-induced disturbances for the conservation of biodiversity. Species contributions to taxonomic (SCBD) and functional (XSCBD) β diversity exhibited positive correlations primarily with species occupancy and abundance, suggesting the potential uniqueness of certain common species. Priority conservation areas in the upstream area and rare but key species such as Tachysurus and Siniperca were identified based on site and species contributions. We thus propose to focus on habitat restoration actions to upstream areas by restricting sand mining, as the current mining activities in the river channel can directly alter riverbed morphology and damage the spawning grounds of fish. We also emphasize the necessity for increased conservation efforts through the development of sustainable recreational fishing policies and stock recovery programs for sensitive species such as Pelteobagrus vachelli and Acheilognathus macropterus. These species have lower SCBD or XLCBD values than others and possess unique feeding habits or high economic value, making them primary targets for recreational fishing. This research highlights the importance of integrating taxonomic and functional β diversity to effectively evaluate biodiversity changes and develop more comprehensive and sustainable conservation strategies for fish diversity conservation.

摘要: This study investigates bacterial species with potential human health implications isolated from blue crab (Callinectes sapidus) in the Northern Adriatic Sea (Italy). The primary objectives include the preliminary characterization of Vibrio, Shewanella, and other pathogenic bacteria, examining their healthcare-related implications, and providing insights into their epidemiology.(#br)Morphometric and cluster analyses revealed significant variations in bacterial prevalence across sampling months and crab sizes, with Vibrio parahaemolyticus being the most abundant species, reaching its highest prevalence in the September samples. Logistic regression indicated that crab length and sampling month were significant factors influencing bacterial isolation, whereas weight and sex had minimal effects.(#br)Antibiotic resistance profiles showed widespread resistance to ampicillin and amoxicillin among several bacterial genera, including Vibrio and Shewanella. Shewanella algae, though less prevalent than Vibrio, demonstrated intrinsic resistance to β-lactams, aligning with its known pathogenic potential in humans. Seasonal variations and environmental changes, such as rising temperatures and salinity, may exacerbate the prevalence and resistance of these pathogens, increasing risks associated with seafood-borne illnesses.(#br)This study highlights the need for further research to understand the interactions between environmental changes, bacterial ecology, and human health risks. Implementing proper seafood handling, cooking practices, and personal protective measures can mitigate potential hazards. These results provide the basis for future studies on bacterial epidemiology and guide strategies for the sustainable management of aquatic ecosystems and seafood safety.

摘要: Nervous necrosis virus (NNV) is a major pathogen in aquaculture, leading to devastating neurological damage and high mortality in fishes; however, its pathogenic mechanism has not been fully elucidated. Insulin-like growth factor binding protein 1 (IGFBP1) is a member of the IGFBP family and acts as a critical modulator in viral infections. Here, we explore the potential role of marine medaka (Oryzias melastigma) IGFBP1 during NNV infection. We found that overexpression of IGFBP1 in marine medaka embryonic stem cells significantly increased NNV capsid protein levels, whereas IGFBP1 knockdown dramatically reduced it, confirming IGFBP1's pro-viral function. Further, we found that m⁶A methylation, particularly mediated by the Wilm's tumor 1-associated protein complex, is crucial for the post-transcriptional enhancement of IGFBP1 expression. Moreover, IGFBP1 overexpression downregulated the expression levels of key components (IRF3, MAVS, TBK1, and TRAF3) in the retinoic acid-inducible gene I-like receptor signaling pathway. This suppression led to reduced activity of the interferon (IFN) 1 promoter and lower expression of IFN and IFN-stimulated genes. Our findings underscore IGFBP1's role in enhancing viral replication and weakening host immune defenses, providing a potential target for therapeutic intervention against NNV infections.

摘要: Understanding biodiversity-ecosystem functioning (BEF) relationships in natural ecosystems is essential for biodiversity conservation and ecological rehabilitation. However, it is unclear whether positive BEF relationships persist under environmental disturbances in freshwater habitats. We examined the biodiversity-biomass production relationship of wetland plant assemblages using observational data: (n ​= ​316 plots) from Yangtze River floodplain lakes with contrasting water level fluctuations. Generalized linear mixed models were constructed to statistically separate the effects of biodiversity and environments on biomass production. Using a unifying Hill diversity framework, we tested the roles of different biodiversity facets (i.e., species diversity, functional diversity, and functional redundancy) and species relative abundance (i.e., rare, common, and dominant species) in driving the biodiversity-biomass relationship. We found that positive biodiversity-biomass relationships persisted for wetland plants in floodplain lakes after removing the effects of environment. Biomass was more strongly related to functional redundancy and species diversity than functional diversity. Common and dominant species were more important than rare species. Both the diversity and biomass of plant assemblages were affected by water level regulation with the former by inundation and the latter by type of water level fluctuations. Our results suggested that positive BEF relationships could persist in periodically disturbed habitats, where both ecosystem resilience and functioning would be promoted by functional redundancy. Rehabilitation of biodiversity and ecosystem functioning in river-floodplains will benefit from water level regulation when requirements of aquatic biota are considered.

摘要: In large reservoirs, spatial gradients are the primary drivers of fish species distributions. However, local characteristics can also influence fish distributions and assemblage structure. We assessed the roles of distance from the dam, water quality characteristics, and physical habitat complexity in determining the richness and abundance of native and non-native fish species in Furnas Reservoir, Brazil. Sampling in April 2023, we collected 22 native and 11 non-native species, increasing the reservoir's richness to 65 species, comprising 51 native and 14 non-native species. Both the richness and abundance of native species were higher in the upper reservoir. These species predominated throughout the entire longitudinal gradient except in the most lacustrine portion (50 ​km from the dam), where non-native species prevailed. Physical habitat condition had little influence in the tested models. Except for total solids, water quality variables were correlated with distance from the dam. Total solids were associated with increased richness and abundance of both native and non-native fish species. We recommend protecting riverine zones in large reservoirs, because of the greater prevalence of native species in them.

摘要: Germ cell transplantation is an effective technique for producing surrogate offspring in fish by transplanting the donor-derived cells into allogeneic or xenogeneic recipients. Spermatogonia are the most commonly used donor stem cells for transplantation due to their easy large-scale acquisition. Despite significant advancements in germ cell transplantation, a comprehensive understanding of the complex regulation of spermatogonia differentiation and development remains a bottleneck in its application to aquaculture.(#br)Our study first unveiled the spermatogonia renewal and differentiation trajectory at a single-cell transcriptomic level in prepubertal male turbot (Scophthalmus maximus). Through scRNA-seq, Monocle analysis, and in situ hybridization, we found that both gdnfa and gdnfb were expressed in spermatogonial stem cells (SSCs) and somatic cells, suggesting the involvement of both autocrine and paracrine pathways of glial cell line-derived neurotrophic factor. Notably, gdnfb showed relatively high expression levels predominantly in SSC-1. Additionally, within the SSC-1 and SSC-2 clusters, we identified gfra1b, nanos2, zbtb16a, and lin28a, which are essential for spermatogonial maintenance in mammals. We also identified grb7 and dnmt3bb.1, two genes that were highly and exclusively expressed in SSC clusters.(#br)In the validation experiments, we found that the addition of GDNF to the SSC culture medium significantly promoted SSC self-renewal and inhibited differentiation. Co-injection of GDNF with turbot SSCs also improved the colonization frequency of donor SSCs in Paralichthys olivaceus triploid larvae. These results provide insights into the proliferation and differentiation trajectory of SSCs, highlighting key marker genes and signaling pathways that regulate SSC self-renewal and differentiation in commercial fish.

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摘要: Regional climate change models for the Pacific Northwest, USA, predict increased summer streamflow intermittency. During low summer flows, fishes experience abiotic (e.g., low dissolved oxygen, high temperature) and biotic (e.g., competition, predation) stressors that can alter individual fish health, population persistence, and fish assemblage structure. In this observational study, we evaluated the impact of decreasing summer streamflow on water physicochemistry, macroinvertebrate abundance, and condition of resident (stream-dwelling) Columbia River redband trout (Oncorhynchus mykiss gairdneri) in Dry Creek, an intermittent stream in southwestern Idaho, USA. During the summer (June to September) of 2019, we used Onset®, HOBO® loggers to monitor stream temperature and dissolved oxygen at 30-min intervals in 10 study reaches within a 3.5 ​km stream section. Current velocity and habitat volume were measured weekly and drifting macroinvertebrates were sampled biweekly in each study reach. Redband trout were collected monthly and we used Fulton’s condition factor (K) as a surrogate for trout health. During the study period, current velocity and habitat volume decreased. Mean daily water temperatures (6.4–22.3 ​°C) were within the reported range for redband trout. However, in late summer, dissolved oxygen fell below the critical limit (5–6 ​mg/L) for salmonids. Macroinvertebrate drift density (number of macroinvertebrates/L) and macroinvertebrate drift biomass (mg/L) did not differ across summer months. However, macroinvertebrate drift rate (number of macroinvertebrates/15 ​min) was significantly lower in August than June or July (p ​< ​0.05). Median K for trout was lower in August (1.01) and September (0.91) than in July (1.25) (p ​< ​0.05). We propose that the decline in redband trout condition was because of intermittency-associated stressors (hypoxic conditions and decreased macroinvertebrate prey).