The roughskin sculpin (Trachidermus fasciatus) is an endangered fish species in China. In recent years, artificial breeding technology has made significant progress, and the population of roughskin sculpin has recovered in the natural environment through enhancement programs and the release of juveniles. However, the effects of released roughskin sculpin on the genetic structure and diversity of wild populations remain unclear. Studies on genetic diversity analysis based on different types and numbers of molecular markers have yielded inconsistent results. In this study, we obtained 2,610,157 high-quality SNPs and 494,698 InDels through whole-genome resequencing of two farmed populations and one wild population. Both farmed populations showed consistent levels of genomic polymorphism and a slight increase in linkage compared with wild populations. The population structure of the two farmed populations was distinct from that of the wild population, but the degree of genetic differentiation was low (overall average Fst = 0.015). Selective sweep analysis showed that 523,529 genes were selected in the two farmed populations, and KEGG enrichment analysis showed that the selected genes were related to amino acid metabolism, which might be caused by artificial feeding. The findings of this study provide valuable additions to the existing genomic resources to help conserve roughskin sculpin populations.

Japanese flounder is usually gonochoristic, with gonads that are either testes or ovaries. Here, we report an unusual case of hermaphroditism in Japanese flounder captured from the Bohai Sea. In the intersex flounder, the membrane of the upper ovary was closely connected to the abdominal muscles and internal organs, and the eggs filled the entire abdomen. The lower ovary was small and closely connected to the testes. The testes contained few fully mature sperm. Both eggs and sperm were capable of fertilization. The levels of several reproduction-related hormones (17β-estradiol, 11-ketotestosterone, 17α, 20β-dihydroxyprogesterone, luteinizing hormone, follicle-stimulating hormone, and testosterone) in the intersex flounder were intermediate, between those in females and males. The results showed that the heterozygosity of the intersex flounder was 0.632, and there were 28 single-nucleotide polymorphisms in the cyp21a gene. Compared with that of wild flounder, the activity of 21-hydroxylase was reduced by approximately 20.0%, and expressions of cyp19a, amh, and dmrt1 differed. We present the first report of its kind, detailing the anatomy, hormonal endocrinology, molecular biology, and physiology of the intersex Japanese flounder.

Lysosome-associated membrane glycoproteins (LAMPs), including lysosomal membrane protein 1 (Lamp1) and lysosomal membrane protein 2 (Lamp2), are involved in phagocytosis, chaperone-mediated autophagy (CMA), and other pathways that interact with lysosomal activity. However, the role of Lamp2 in teleosts has not been clarified. In this study, we investigated the functions of lamp2 genes during Vibrio vulnificus infection. We achieved subcellular localization of the lamp2 gene at the cellular level and performed overexpression and RNA interference experiments followed by Lipopolysaccharides (LPS) stimulation to probe the expression changes of related genes. Ultrapathology analysis of the head-kidney revealed an increase in lysosomes and the formation of autophagosomal vesicles after V. vulnificus infection, suggesting that lysosomes bind to autophagosomes. The lamp2 gene, encoding 401 amino acids in Cynoglossus semilaevis, was constitutively expressed in all examined tissues of healthy half-smooth tongue sole, with the highest expression in blood. A challenge test was conducted to assess the response of half-smooth tongue sole (Cynoglossus semilaevis) to different concentrations of V. vulnificus. The results showed that the relative expression of lamp2 and its related genes—lc3, rab7, vamp8, atg14, stx17, snap29, ctsb, and ctsd—varied with time and concentration in the gill, spleen, head-kidney, blood, liver, and gut tissues. From the results of lamp2 gene overexpression and RNA interference experiments, it is hypothesized that lamp2 positively regulates lc3, rab7, vamp8, snap29, and stx17, and negatively regulates ctsd and ctsb. Our findings provide new primary data for the function of lamp2 gene in the half-smooth tongue sole., particularly its role in regulating the immune response against V. vulnificus.