Invertebrate Survival Journal

Cloning and subcellular localization of silkworm suppressor of cytokine signaling 6 and its expressional changes in response to the infection of Bombyx mori nucleopolyhedrovirus

2024-04-08T09:37:12+00:00

The role of suppressor of cytokine signaling (SOCS) 6 in the silkworm growth and development and in the immune response to Bombyx mori nucleopolyhedrovirus (BmNPV) infection remains largely unclear. In this study, we cloned the ORF of silkworm SOCS6, named as BmSOCS6. We found that BmSOCS6 locates mainly in cytoplasmic space, and expresses at the highest level in embryogenesis. BmSOCS6 expresses relatively highly in the fat body of BmNPV-susceptible silkworm 306 but lowly in BmNPV-resistant silkworm NB and BC8, and BmNPV inoculation further reduces its expression with more pronounced effect in NB and BC8 than 306. However, BmSOCS6 expression in the midgut and hemolymph decreases without BmNPV inoculation but recovers with BmNPV inoculation, both of which are more pronounced in NB and BC8 than 306. BmNPV inoculation also induces a general down-regulation of BmSOCS6 expression in BmN cells. SOCS6 has previously been shown to positively regulate apoptosis and negatively regulate the production of antimicrobial peptides (AMPs). Therefore, compared to susceptible silkworms, BmSOCS6 may promote apoptosis in the midgut and hemolymph with increased expression and enhance the production of AMPs in the fat body with decreased expression, contributing to the resistance to BmNPV infection in resistant silkworms.

Sequence features and expression profiles of a novel α-amylase gene from Chinese mitten crab Eriocheir sinensis

2024-04-08T09:53:55+00:00

Amylase is the main digestive enzyme in crustaceans, and plays extremely important roles in metabolism, growth and development. Some studies have also shown that amylase may play a role in the immune defense system of aquatic organisms. In this study, a novel α-amylase gene (designated as EsAMY) was cloned and identified from Chinese mitten crab Eriocheir sinensis. The complete cDNA sequence of EsAMY contained a 5' untranslated region (UTR) of 39 bp, a 3' UTR of 70 bp with a polyA tail, and an open reading frame (ORF) of 1554 bp encoding a polypeptide of 517 amino acids with the predicted molecular weight of 56.9 kDa. The deduced amino acids sequence of EsAMY contained conserved cysteine site, active catalytic site, calcium binding site and chloride binding site, which was similar with previously identified α-amylase genes in other species. Quantitative real-time PCR (qPCR) analysis showed that EsAMY transcripts were detectable in all the tested tissues, with the highest mRNA expression levels in hemocytes. Both Aeromonas hydrophila and polybrominated diphenyl ether-47 (BDE-47) stimulation could significantly induce the mRNA expression of EsAMY gene in hemocytes, and its responses to A. hydrophila was more intense than those of BDE-47. These results indicate that EsAMY is a new member of the amylase family and may be involved in the immune response of Chinese mitten crab to both invasive microorganisms and external pollutant stimulation.

Sequence characterization and expression analysis of a PDGF/VEGF related factor gene in swimming crab Portunus trituberculatus

2024-02-23T09:12:25+00:00

PDGF/VEGF factors are closely associated with immune defense systems. In this study, a PDGF/VEGF related factor gene (designated as PtPVF) from swimming crab Portunus trituberculatus was identified and analyzed. Its full-length cDNA is 1320 bp, containing an open reading frame (ORF) of 582 bp, 5’ untranslated regions (UTR) of 105 bp and 3’ UTR of 633 bp, which encoded a polypeptide of 193 amino acid residues. The deduced amino acid sequence of PtPVF contained a signal peptide, a typical PDGF/VEGF domain, and a cysteine knot motif (CXCXC). Quantitative real-time PCR analysis demonstrated that the mRNA of PtPVF was detectable in gills, gonads, heart, hemocytes, hepatopancreas, intestines, muscles, optic stalk, stomach, and the highest level was found in hemocytes, followed by gill and hepatopancreas. After stimulation by Vibrio alginolyticus, pentachlorophenol (PCP) or cadmium chloride (CdCl2), the relative mRNA expression levels of PtPVF in hemocytes reached their respective peaks at 3 h, 6 h and 6 h, and 36.61-fold, 3.06-fold and 21.26-fold compared with the original level, respectively, and the respond to V. alginolyticus and CdCl2 is earlier than to PCP, while under the challenge of V. alginolyticus and CdCl2, the mRNA expression level of PtPVF was significantly higher than that of PCP stimulation. Furthermore, the mRNA expression level of PtPVF first decreased at 3 h and then increased rapidly to a peak at 6 h after PCP challenge. All these results demonstrated that PtPVF might be involved in the response to invading pathogens and environmental pollution stimulants of P. trituberculatus.