The Chinese soft-shelled turtle (Pelodiscus sinensis) is an important aquaculture reptile with rich nutritional and medicinal values. In recent decades, the wild resources of P. sinensis have been depleting due to natural and artificial factors. Herein, we report the complete mitochondrial genome of four P. sinensis strains, including the Japanese (RB) strain, Qingxi Huabie (HB) strain, Jiangxi (JB) strain, and Qingxi Wubie (WB) strain. The nucleotide composition within the complete mitogenomes was biased towards A + T with a variable frequency ranging from 59.28% (cox3) to 70.31% (atp8). The mitogenomes of all four strains contained 13 protein-coding genes (PCGs), 22 tRNAs, 2 rRNAs, 1 control region, and a replication origin region of the L-strand replication (OL), which was consistent with most vertebrates. Additionally, the atp8, nad4l, nad6, and nad3 genes possessed high genetic variation and can be used as potential markers for the identification of these P. sinensis strains. Additionally, all PCGs genes were evolving primarily under purifying selection. Through comparative analysis, it was revealed that most of the tRNAs were structurally different in the TψC stem, DHU stem, and acceptor stem. The length of the tandem repeats in the control region was variable in the four P. sinensis strains, ranging from 2 bp to 50 bp. Phylogenetic analysis indicated that all P. sinensis strains clustered into one branch and were closely related to other Trionychinae species. Overall, this study provides mitochondrial genome information for different P. sinensis strains to support further species identification and germplasm resource conservation.

Trionyx sinensis hemorrhagic syndrome virus (TSHSV) is an aquatic arterivirus causing a high mortality rate for T. sinensis (Chinese soft-shelled turtle), but the detailed infection properties of TSHSV are unclear, and no effective treatment is available. In this study, cell culture and histopathology were performed to elucidate the infection properties of TSHSV. Furthermore, the anti-TSHSV and immune-enhancing effects of curcumin were evaluated using survival statistics, qPCR, and tissue immunofluorescence. The results demonstrated that TSHSV could proliferate in the spleen cell line of T. sinensis, leading to cytopathic effects. TSHSV damaged the livers, kidneys, and lungs, characterized by cell disintegration and hyperemia. Curcumin at 250 mg/kg improved the survival of T. sinensis, and significantly reduced the viral load in the spleens, kidneys, and lungs. Moreover, curcumin inhibited the mRNA expression of immune-related genes, RSAD2, IFN-γ, and TNF-α (p < 0.05). In conclusion, these results imply that TSHSV is pathogenic to the spleen cell line, liver, spleen, kidney, and lung of T. sinensis. Curcumin effectively inhibits TSHSV and modulates the immune function of T. sinensis, so it holds promise as a means to prevent TSHSV.

The pathogenic Bacillus cereus strain XS0724 isolated from China can cause high lethality to Trionyx sinensis, but little information is available on their detailed interactions. In this study, histopathologic profiling indicated that B. cereus caused vacuolization and cell necrosis in the liver, spleen, kidney, and intestine. The identification of the virulence factor genes non-hemolytic enterotoxin (Nhe), hemolysin BL (Hbl), and enterotoxin FM (entFM) confirmed bacterial pathogenicity. Splenic transcriptomic sequencing at 96 h post-infection identified various immune-related genes mapped to diverse gene families, including interleukin, complement, chemokine, and interferon. The differentially expressed genes (DEGs) were enriched in 2174 GO terms: 1694 in biological processes, 138 in cellular components, and 342 in molecular functions. Further KEGG enrichment indicated that DEGs were primarily associated with the phagosome, NF-kappa B signaling pathway, and PI3K-Akt signaling pathway. The DEGs and enriched pathways may be involved in the elimination of invasive B. cereus. These data laid the foundation for elucidating the potential molecular mechanisms in this bacterial infection process, and provided robust genetic evidence for subsequent work on resistance genes of T. sinensis.

White spot disease, caused by the parasitic Ichthyophthirius multifiliis, induces mortality exceeding 80% in intensive aquaculture systems, resulting in global annual losses of >$1 billion. Current chemical controls (e.g., formaldehyde) face environmental persistence and drug resistance challenges. This study developed a synthetic isoquinoline derivative, BHTCA (s)-2-tert-butoxycarbonyl-7-hydroxy-1,2,3,4-tetrahydroisoquinoline-3-carboxylic acid), as a biodegradable alternative against I. multifiliis in grass carp (Ctenopharyngodon idella). In vitro assays revealed stage-selective efficacy: theronts exhibited higher susceptibility (EC₅₀ = 0.10 mg/L at 4 h) than tomonts (EC₅₀ = 0.40 mg/L at 24 h), with BHTCA disrupting ciliary structures and compromising cyst integrity. In vivo trials (0.6 mg/L) reduced parasite loads by 78.1% and host mortality by 66.7% versus untreated controls. Acute toxicity tests confirmed a high therapeutic index (LC₅₀ = 16.75 mg/L; >167× effective concentration). With demonstrated efficacy, low production cost, and minimal eco-toxicity, BHTCA presents a sustainable strategy for Ichthyophthiriasis management in aquaculture.