摘要: The shell, a type of biological exoskeleton, is a critical feature of bivalves, serving key functions including protection, locomotion, and structural support. Although bivalve shell morphology exhibits rich and complex variability, research on the genetic basis of this diversity remains limited. The dwarf surf clam, Mulinia lateralis, with its rapid growth and short generation interval, serves as an ideal model organism for bivalves, displaying notable shell morphology diversity. In this study, we performed high-throughput sequencing on 180 individuals, obtaining 32,318 SNPs to investigate the genetic basis of shell morphology variation in M. lateralis. The heritability of shell morphological traits was high, with values ranging from 0.439 to 0.814. Through genome-wide association study (GWAS), we identified 20 single nucleotide polymorphisms (SNPs) associated with shell morphology traits and screened 16 candidate genes, such as Lox4, AJM1-like, and Luc7l. These genes are implicated in the determination of an anteroposterior (A-P) body plan and the regulation of cytoskeletal structure and growth. Of particular interest is Lox4, which is prominently expressed during the trochophore stage and in the adult mantle tissue, playing a crucial role in shell formation in bivalves. Sanger sequencing confirmed that the SNP Chr15-22361661 located in the Lox4 gene exhibited significant dimorphism in the validation population. Individuals with the AA-genotype exhibited a diminished short-long beak length ratio (SLBR) trait alongside an upregulation of Lox4 expression (p ​< ​0.05). RNA interference (RNAi) experiments further revealed that the inhibition of Lox4 expression altered shell morphology, leading to an increase in SLBR (p ​< ​0.05). Additionally, the inhibition of Lox4 expression resulted in a downregulation of Lox2 expression, whereas the suppression of Lox2 did not affect the expression of Lox4. These results suggest the presence of a unidirectional regulatory cascade wherein Lox4 modulates Lox2 to influence shell morphology. These findings reveal genetic variations associated with shell morphology in M. lateralis and highlight the potential regulatory roles of Lox4 and homeobox clusters on bivalve shell morphology, which enhance our understanding of the genetic basis of shell morphological diversity in bivalves and provide novel insights into how they adapt to diverse lifestyles.

摘要: Climate change has been considered a major cause of the increase in the average water temperature of many water systems worldwide and has become a leading factor affecting various ecosystems. The rise in water temperature causes a threat to aquatic ecosystems. Most reports focus on assessing the direct impact of water temperature changes on the behavior, physiology, and distribution of aquatic species. This study used experimental models with two small fish species, Japanese medaka (Oryzias latipes) and mosquitofish (Gambusia affinis), which are commonly found living in the same habitat of shallow freshwater, to assess their tolerance to changes in water temperature over a wide temperature range (6–36 ​°C) and their interactions in cohabitation at different temperatures. The results showed that mosquitofish has a better ability to adapt to high water temperature ranges than medaka while medaka adapt better than mosquitofish to low water temperature ranges. In a cohabitation environment, increases in water temperature boosted the mortality of medaka. Observations of the behavior of the two fish species at temperatures of 18 and 28 ​°C showed that when shifting between these two temperatures, the aggressive behavior of male and female mosquitofish towards male and female medaka changed. In medaka, this change only appeared in males. These findings have important implications for a better understanding of the profound impacts of climate change on species interactions in natural conditions in aquatic ecosystems.

摘要: The success of initial feeding during the mouth-opening stage is crucial for the survival and growth of fish larvae. Carnivorous mandarin fish (Siniperca chuatsi) face unique challenges in capturing live prey during this period. The aim of this study was to explore the factors influencing initial feeding in mandarin fish larvae during the mouth-opening stage and validate their functional roles. Transcriptomic analysis of both first feeding and unfed larvae revealed significant changes in the expression of genes related to vision and taste, while fewer changes were observed in genes associated with olfaction. Further sensory inhibition experiments demonstrated that vision and taste are the primary sensory factors driving initial feeding, while olfaction plays a less significant role. Gene set enrichment analysis revealed that the mammalian target of rapamycin (mTOR) is a core regulatory factor in this process. In situ hybridization indicated significant changes in the expression and distribution of mTOR, agouti-related peptide (AgRP), and neuropeptide Y (NPY) before and after feeding. Rapamycin-mediated mTOR inhibition significantly reduced the expression of appetite stimulants (NPY, AgRP, GHRL, and orexin1) and decreased feeding rates. Moreover, we found that inhibiting mTOR signaling also lowered the expression of key digestive enzymes, including pepsin, lipase, and trypsin. In summary, our study identifies vision and taste as the primary sensory factors influencing initial feeding in mandarin fish and clarifies the critical role of the mTOR pathway in coordinating appetite regulation and digestive preparation. These mechanistic insights provide promising targets for improving feeding habit programs for this economically valuable species.

摘要: The Asian swamp eel (putatively Monopterus albus) is recognized as one of the most economically significant specialty freshwater fishes in China. Nonetheless, there is a lack of systematic research on eel population genetics utilizing genome-wide analyses. This study sequenced the genomes of 559 eel samples from 37 regions in Asia, identifying 82.71 million single nucleotide polymorphisms and revealing the existence of multiple genetic structure breaks in the eel population. Combining phylogenetic and population structure analyses with genetic differentiation and kinship heat maps, we classified Asian swamp eel populations into three clusters at the macroscopic level and hypothesized that they each belonged to different species within the genus Monopterus. These findings reveal cryptic and complex diversification, attributed to geographical isolation and both artificial and natural selection. Furthermore, we analyzed the evolutionary origins of the eel based on the available data and hypothesized that it originated in the South Asian subcontinent of Bangladesh. This work determined the evolutionary history and genetic diversity of eel populations, alongside the selection mechanisms potentially influencing their adaptations. These findings will provide new insights into the genetic structure of the species, aimed at establishing a foundation for the conservation and management of eel genetic diversity and the selection of high-quality germplasm in the future.

摘要: Plastics provide a range of benefits in our society, even if waste plastics are representing a worrying issue for the environment. In addition, various additives, i.e., chemical substances added to plastic polymers to enhance their properties, create complications in their lifecycle. In fact, inappropriate use and recycling of plastics inevitably leads to the release of toxic substances. In this work we analyzed the possible toxic effects of microplastics obtained from commercial cups made from polypropylene (PP) and from the biodegradable polymer poly (lactic acid) (PLA), on the sea urchin Paracentrotus lividus (Lmk) embryos. We exposed eggs of P. lividus to microplastics derived from PLA and PP cups for 10 ​min at increasing concentrations. The eggs were then fertilized and the embryonic development was followed until the pluteus stage at 48 ​h post fertilization (hpf). Our results showed that neither PLA nor PP microplastics had a measurable effect on fertilization, but both affected the first mitotic division, induced delay of embryonic development with many embryos still at blastula and gastrula stages at 48 hpf, and caused malformations in embryos that reached the pluteus stage. Moreover, the expression level of several genes involved in different functional pathways linked to stress and detoxification responses, development, differentiation and skeletogenesis were followed by Real time qPCR, with the aim of identifying the molecular targets of PLA and PP. These morphological effects were a result of the up-regulation of most of the genes analyzed and used by the embryos to react to the detrimental effects induced by plastics. Our findings highlighted the important issue of plastic additives, which can be released during the various recycling and recovery processes of contaminated ecosystems.

摘要: Pacific white shrimp (Penaeus vannamei) is a globally important aquaculture species, prized for its adaptability, high yield, and economic value. Growth traits are key determinants of aquaculture profitability, making it essential to understand their genetic basis. In this study, we performed whole-genome sequencing of 996 individual P. vannamei, identifying 2,706,353 high-quality SNPs through genotyping and imputation. A genome-wide association study (GWAS) revealed six quantitative trait loci (QTLs) on linkage group (LG) 2, 25, 26, and 37, with 30 SNPs significantly associated with body length. The most significant associations were located on LG37, encompassing PDE11A, SAAL, IAO-like, and several other genes potentially involved in molting and growth regulation. Functional validation through RNA interference demonstrated that silencing PDE11A and SAAL significantly reduced growth, confirming their critical role in growth modulation. This integrative approach, combining a GWAS with functional genomics, sheds light on the molecular mechanisms governing in P. vannamei. The identification and validation of PDE11A and SAAL as key growth-related genes offer valuable insights for developing selective breeding strategies to improve growth traits in aquaculture species.

摘要: Fishery trade plays a significant role in the global food system, though some studies have found that this trade may increase the risk of spreading pathogens. However, research providing quantitative evidence into this relationship is lacking. In this study, we analyzed data pertaining to pathogens carried by aquatic animals from NCBI databases and the fishery trade from FAO Global Fish Trade Statistics. The results showed that the risk of carrying pathogens was not equal for various species and areas. Actinopterygii, Bivalvia, and Anthozoa were identified as major host classes, while Callinectes sapidus, Channa punctata, Cirrhinus mrigala, Clarias magur, Mystus tengara, Phocarctos hookeri, Sperata seenghala, Amphalius runatus, Callopsylla caspia, and Megabothris turbidus were recognized as key hosts. Compared with traded species, non-traded species emerged as the largest carrier of all pathogens. Moreover, countries with higher fishery trade value tended to report more pathogens. In conclusion, our study suggested that current worldwide fishery trade may facilitate the spread of pathogens carried by aquatic products. Findings from this work advance our understanding of the risks of infectious diseases, with relevance for public health monitoring and safety from a global perspective.

摘要: Aquatic vegetation plays a crucial role in wetland ecosystems but are sensitive to human activities, especially in urban lakes where the loss of aquatic plant diversity is pronounced. Recently, there has been increasing interest in whether the restoration of urban lakes can alleviate ecological degradation, with changes in aquatic plant diversity serving as important ecological indicators. However, methods for evaluating aquatic plant community diversity still require further refinement. Despite the widespread application of environmental DNA (eDNA) in monitoring aquatic biota, its use for assessing aquatic plant community diversity, particularly through metabarcoding methods remains limited. This study assessed aquatic plant diversity and spatial distribution patterns in Donghu Lake and its surrounding wetlands, a typical eutrophic urban lake in China, using both traditional community surveys and eDNA methods. Surveys covered both the littoral zone and open water areas, and considered various eDNA sample types. A total of 69 aquatic plant species were identified by eDNA while 50 were identified by traditional survey methods. This shows that eDNA identified more aquatic plant species than traditional survey methods. Both methods showed similar levels of aquatic plant diversity (alpha diversity) within each habitat type, with no significant differences found between the methods in either the ponds or the lake area. In contrast, both methods consistently identified significant differences in aquatic plant community composition (beta diversity) between the pond and lake areas. Moreover, distinct plant communities were found in different areas of the pond, while no significant variation was observed among regions within the lake. This study provides crucial data for assessing biodiversity in an urban lake, suggesting the potential mitigation of aquatic ecological degradation in Donghu Lake. Our findings also demonstrate the potential of eDNA metabarcoding as a tool for evaluating aquatic plant diversity in habitats within lentic ecosystems.

摘要: As one of the world's “staple” freshwater fish species, black carp (Mylopharyngodon piceus) faces critical challenges from bacterial diseases. Toll-like receptors (TLRs), serving as frontline pathogen sensors, play crucial roles in antibacterial defense. This study systematically identified 21 TLR members through genomic analysis, revealing their uneven distribution across 11 chromosomes with evolutionarily conserved synteny in cyprinids. Phylogenetic reconstruction, sequence, and selection pressure assessment demonstrated that TLR subfamilies maintain structural and sequence conservation and undergo strong purifying selection. Tissue-specific transcriptome profiling showed broad TLR expression patterns, with several members exhibiting significant differential expression in Aeromonas hydrophila-resistant populations. Functional validation focused on the most prominently altered MpTLR1 revealed that its knockdown increased infection-induced mortality and exacerbated histopathological damage. Mechanistic investigations demonstrated that MpTLR1 suppression significantly impaired antioxidant enzyme activities (antioxidant capacity and superoxide dismutase), complement C3 levels and lysozyme activity, while downregulating mRNA expression levels of pro-inflammatory cytokines (TNF-α, IFN-γ2, and IL-6), complement C3, and antimicrobial peptides (hepcidin and liver-expressed antimicrobial peptide 2). Our work provides a systematic characterization of black carp TLRs and establishes MpTLR1's pivotal role in bacterial immunity through coordinating antioxidant defense and inflammatory responses. These findings offer insights for breeding A. hydrophila-resistant black carp populations.

摘要: Human activities, such as hydropower generation, irrigation, and flood control, have led to the extensive construction of dams, significantly impacting river ecosystems worldwide. These structures disrupt the river system and alter the natural flow characteristics of river channels, disrupting the continuity and connectivity of aquatic ecosystems. The loss of free-flowing river basins often leads to the deterioration of water conditions, including changes in temperature, dissolved oxygen levels, and nutrient concentrations, which negatively affect aquatic biodiversity. Benthic macroinvertebrates, being highly sensitive to alterations in their habitat, are particularly vulnerable to these changes. This study evaluated the impacts of river connectivity on water quality, and the diversity and community assembly of benthic macroinvertebrates in the Yangtze River Basin, the longest and largest watershed in China. The results indicated the following: (1) Dam-induced connectivity loss significantly affects benthic macroinvertebrate diversity and community composition. Reduced connectivity limits species dispersal, decreasing α-diversity while driving shifts in β-diversity along connectivity gradients, (2) Dam-induced connectivity changes influence benthic macroinvertebrate diversity primarily through water quality alterations. Further, reduced river connectivity modifies flow regimes, resulting in changes to key water quality parameters and degraded habitat conditions for benthic communities. Our findings provide crucial insights into the ecological consequences of river fragmentation and highlight the importance of maintaining connectivity for conserving aquatic biodiversity.