Toxicological effects benzotriazole to the marine scallop Chlamys nobilis: a 2-month exposure study.

Benzotriazole and its associated derivatives (BTs) are widely used as ultraviolet stabilizers and corrosion inhibitors. They have been extensively found in marine environments and are bioaccumulative through the food chain. However, the toxicities of BTs to marine organisms are seldom identified and no assessment has been conducted for filter-feeding bivalves. In this study, a marine scallop Chlamys nobilis was exposed to 0, 0.01, 0.1, and 1.0 mg/L of BT for 60 days. Effects of BT on endocrine system, cytochrome P450 activity, antioxidant activity, and neural activity of C. nobilis were examined. The results showed that BT exerted significant estrogenic effects on both male and female scallops and inhibited EROD activities of C. nobilis even at 0.01 mg/L level. BT at ≥ 0.01 mg/L levels also caused significant oxidative stress on C. nobilis. Moreover, most of the adverse effects of BT to C. nobilis were found from day 35 and 0.01 mg/L was the lowest concentration with observed effects, showing the long-term toxic effects of BT to C. nobilis. Thus, the adverse effects of BT and its derivatives to marine benthic communities deserve more attention in future research.

Tumor necrosis factor receptor-associated factor 6 (TRAF6) participates in anti-lipopolysaccharide factors (ALFs) gene expression in mud crab.

Tumor necrosis factor receptor-associated factor 6 (TRAF6) is a key cytoplasm signal adaptor that mediates signals activated by tumor necrosis factor receptor (TNFR) superfamily and the Interleukin-1 receptor/Toll-like receptor (IL-1/TLR) superfamily. The full-length 2492 bp TRAF6 (Sp-TRAF6) from Scylla paramamosain contains 1800 bp of open reading frame (ORF) encoding 598 amino acids, including an N-terminal RING-type zinc finger, two TRAF-type zinc fingers and a conserved C-terminal meprin and TRAF homology (MATH) domain. Multiple alignment analysis shows that the putative amino acid sequence of Sp-TRAf6 has highest identity of 88% with Pt-TRAF6 from Portunus trituberculatus, while the similarity of Sp-TRAF6 with other crustacean sequences was 54-55%. RT-PCR analysis indicated that Sp-TRAF6 transcripts were predominantly expressed in the hepatopancreas and stomach, whereas it was barely detected in the heart and hemocytes in our study. Moreover, Sp-TRAF6 transcripts were significantly up-regulated after Vibrio parahemolyticus and LPS challenges. RNA interference assay was carried out used by siRNA to investigate the genes expression patterns regulated by Sp-TRAF6. The qRT-PCR results showed that silencing Sp-TRAF6 gene could inhibit SpALF1, SpALF2, SpALF5 and SpALF6 expression in hemocytes, while inhibit SpALF1, SpALF3, SpALF4, SpALF5 and SpALF6 expression in hepatopancreas. Taken together, the acute-phase response to immune challenges and the inhibition of SpALFs gene expression indicate that Sp-TRAF6 plays an important role in host defense against pathogen invasions via regulation of ALF gene expression in S. paramamosain.

Cloning and respond of a cold shock domain protein (CnCSDP) gene to cold stress in noble scallop Chlamys nobilis (Bivalve: Pectinidae).

Cold shock domain proteins (CSDPs) play various roles in cellular processes, including adaptation to low temperature in mollusk. In this study, the cDNA encoding CSDP in noble scallop Chlamys nobilis was cloned (CnCSDP), and its transcript profile in cold-stressed orange and brown strains was analyzed using real-time RT-PCR. Bioinformatic analysis shows that the complete CnCSDP cDNA is 1,434 bp in length, consisting of a 5'-, and 3'-untranslated region of 86 and 466 bp, respectively, and a 882 bp open reading frame encoding 294 amino acids with an estimated molecular mass of 33.23 kDa and an isoelectric point of 9.72. Furthermore, CnCSDP has two consensus RNA binding domains, four DNA binding sites and four RGG repeats. CnCSDP transcripts amount in the blood of orange strain were significantly higher, while in the mantle were much lower than that of brown strain. In the cold-stressed orange strain, CnCSDP mRNA decreased dramatically in the blood and mantle, but was significantly up-regulated at 1 h, and progressively returned to its original levels in the gill. In the cold-stressed brown strain, CnCSDP transcripts were significantly up-regulated at 6 h in the blood, decreased dramatically in the mantle, while mostly maintained unchanged in the gill. Lastly, significantly positive correlation was found between the CnCSDP transcripts amount and total carotenoids content in the gill in both orange and brown strain. This study will be helpful for understanding the molecular mechanism underlying cold stress in noble scallop in the further.