Envenomation by two medically important Sundaic pit vipers, Trimeresurus wiroti (Malaysia) and Trimeresurus puniceus (Indonesia), causes hemotoxic syndrome with a potentially fatal outcome. Research on the compositions and antigenicity of these pit viper venoms is however lacking, limiting our understanding of the pathophysiology and treatment of envenomation. This study investigated the venom proteomes of both species through a protein decomplexation strategy, applying C18 reverse-phase high-performance liquid chromatography followed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), and protein identification through nano-electrospray ionization liquid chromatography-tandem mass spectrometry (nano-ESI-LCMS/MS) of trypsin-digested peptides. The venom antigenicity was profiled against the Thai Green Pit Viper Antivenom (GPVAV, a hetero-specific antivenom), using indirect enzyme-linked immunosorbent assay (ELISA). The venom proteomes of T. wiroti and T. puniceus consisted of 10 and 12 toxin families, respectively. The major proteins were of diverse snake venom serine proteases (19-30% of total venom proteins), snake venom metalloproteinases (17-26%), disintegrins (9-16%), phospholipases A2 (8-28%) and C-type lectins (~8%). These were putative snake toxins implicated in hemorrhage and coagulopathy, consistent with clinical hemotoxicity. GPVAV showed strong immunorecognition toward high and medium molecular weight proteins (e.g., SVMP and PLA2) in both venoms, while a lower binding activity was observed toward small proteins such as disintegrins. Conserved antigenicity in the major hemotoxins supported toxicity cross-neutralization by GPVAV and indicated that the immunorecognition of low molecular weight toxins may be optimized for improved binding efficacy. Taken together, the study provides insights into the pathophysiology and antivenom treatment of envenomation caused by T. wiroti and T. puniceus in the region.
A comprehensive bioinformatics analysis was conducted to elucidate the innate immune response of Charybdis japonica following exposure to Aeromonas hydrophila. This study integrated metabolomics, 16S rRNA sequencing, and enzymatic activity data to dissect the immune mechanisms activated in response to infection. Infection with A. hydrophila resulted in an increased abundance of beneficial intestinal genera such as Photobacterium spp., Rhodobacter spp., Polaribacter spp., Psychrilyobacter spp., and Mesoflavibacter spp. These probiotics appear to suppress A. hydrophila colonization by competitively dominating the intestinal microbiota. Key metabolic pathways affected included fatty acid biosynthesis, galactose metabolism, and nitrogen metabolism, highlighting their role in the crab's intestinal response. Enzymatic analysis revealed a decrease in activities of hexokinase, phosphofructokinase, and pyruvate kinase, which are essential for energy homeostasis and ATP production necessary for stress responses. Additionally, reductions were observed in the activities of acetyl-CoA carboxylase and fatty acid synthase. Gene expression analysis showed downregulation in Peroxiredoxin 1 (PRDX1), Peroxiredoxin 2 (PRDX2), glutathione-S-transferase (GST), catalase (CAT), and glutathione (GSH), with concurrent increases in malondialdehyde (MDA) levels, indicating severe oxidative stress. This study provides insights into the molecular strategies employed by marine crabs to counteract bacterial invasions in their natural habitat.
Triacylglycerol (TAG) is crucial in animal energy storage and membrane biogenesis. The conversion of diacylglycerol (DAG) to triacylglycerol (TAG) is catalyzed by diacylglycerol acyltransferase enzymes (DGATs), which are encoded by genes belonging to two distinct gene families. Although arthropods are known to possess DGATs activities and utilize the glycerol-3-phosphate pathway and MAG pathway for TAG biosynthesis, the sequence characterization and evolutionary history of DGATs in arthropods remains unclear. This study aimed to comparatively evaluate genomic analyses of DGATs in 13 arthropod species and 14 outgroup species. We found that arthropods lack SOAT2 genes within the DGAT1 family, while DGAT2, MOGAT3, AWAT1, and AWAT2 were absent from in DGAT2 family. Gene structure and phylogenetic analyses revealed that DGAT1 and DGAT2 genes come from different gene families. The expression patterns of these genes were further analyzed in crustaceans, demonstrating the importance of DGAT1 in TAG biosynthesis. Additionally, we identified the DGAT1 gene in Swimming crab (P. trituberculatus) undergoes a mutually exclusive alternative splicing event in the molt stages. Our newly determined DGAT inventory data provide a more complete scenario and insights into the evolutionary dynamics and functional diversification of DGATs in arthropods.
Studying differences in transcriptomes across various development stages of insects is necessary to uncover the physiological and molecular mechanism underlying development and metamorphosis. We here present the first transcriptome data generated under Illumina Hiseq platform concerning Zeugodacus tau (Walker) larvae from Nanchang, China. In total, 11,702 genes were identified from 9 transcriptome libraries of three development stages of Z. tau larvae. 7219 differentially expressed genes (DEGs) were screened out from the comparisons between each two development stages of Z. tau larvae, and their roles in development and metabolism were analyzed. Comparative analyses of transcriptome data showed that there are 5333 DEGs between 1-day and 7-day old larvae, consisting of 1609 up-regulated and 3724 down-regulated genes. Expressions of DEGs were more abundant in L7 than in L1 and L3, which might be associated with metamorphosis. Gene Ontology (GO) enrichment and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis suggested the enrichment of metabolic process. KOG annotation further confirmed that 20-hydroxyecdysone (20E) pathway related genes Cyp4ac1_1, Cyp4aa1, Cyp313a4_3 were critical for the biosynthesis, transport, and catabolism of secondary metabolites and lipid transport and metabolism. Expression patterns of 8 DEGs were verified using quantitative real-time PCR (RT-qPCR). This study elucidated the DEGs and their roles underlying three development stages of Z. tau larvae, which provided valuable information for further functional genomic research.
Redtail shrimp Fenneropenaeus penicillatus are commercially important shrimp species. However, the aquaculture of this species is hindered by insufficient seed supply, mainly caused by frequent inadequate gonad development. The vitellogenin receptor (VgR) plays an important role in the gonad development of oviparous animals by facilitating the accumulation of vitellogenin and nutrients in the oocytes. Therefore, in this study, we cloned and functionally characterized a novel VgR from F. penicillatus (FpVgR). In general, FpVgR has a length of 3795 bp, encoding 1264 amino acid residues and encompassing 28 exons. The calculated molecular weight and theoretical isoelectric point of FpVgR were 139.18 kDa and 4.76, respectively. FpVgR mRNA was highly expressed in the ovary at developmental stages 3 and 4, and localized in the oocyte's plasma membrane. Knocking down FpVgR significantly reduced transcription levels in ovarian tissue, resulting in DNA damage and cell apoptosis within the ovarian tissues. The results of transcriptomic profiling following FpVgR knockdown also revealed that the apoptosis signaling pathway and oxytocin signaling pathway were involved in regulating ovary development and maintaining homeostasis. These findings offer valuable understanding into the mechanisms governing vitellogenesis and the maturation of oocytes, with a specific focus on FpVgR, contributing to future research on vitellogenesis and ovarian development in F. penicillatus.
This study investigated the effects of short-term exposure to flavonoids, specifically quercetin and taxifolin, on the transcriptomic responses of Chinese sucker (Myxocyprinus asiaticus) to validate their influence on gene expression related to immunity, antioxidant activity, and metabolism. Using transcriptomic data, we also analyzed their influence on relevant immune genes and examined the Chinese suckers' resistance to A. hydrophila. Oxidative stress, immune defense, and glucose metabolism of Chinese suckers were tested to assess potential enhancements. Significant alterations were observed in multiple immune-related Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways in the liver of Chinese suckers, notably the complement and coagulation cascades, degradation of aromatic compounds, and xenobiotic metabolism by cytochrome P450. The key immune markers such as UGT, MPO, C3, and C4 were highlighted in these pathways, underlining their importance in fish immunity. Additionally, oxidative stress related KEGG pathways were notably influenced after exposure to quercetin and taxifolin, displaying markers such as CYP3A, superoxide dismutase, GST, malondialdehyde, and catalase. Quercetin particularly affected the enzymatic activity of glucose oxidase, hexokinase, phosphofructokinase, and ATPase, which are enzymes related to stress responses in fish. Antimicrobial tests revealed that both flavonoids enhanced Chinese suckers' defense against A. hydrophila by bolstering oxidative stress resistance and immunity. These results provided valuable insights for using flavonoids to enhance fish immunity.