中国对虾受病原菌调节表达的五种胰蛋白酶

Five trypsins designated as Fctry1-1, Fctry1-2, Fctry2，Fctry3, and Fctry4 were obtained from the hepatopancreas of the Chinese shrimp Fenneropenaeus chinensis. Accordingly, four Fctrypsins, namely, Fctry1-1, 1-2, 2, and 3, were observed to have conserved the catalytic triad (H, D, and S), while in Fctry4, one of the catalytic triad S was substituted by F, and the mature peptide was found to be inactive. Further analysis for similarities was also conducted, with the results indicating that the characteristics of these trypsins are identical with those of trypsins from the Pacific white shrimp (Litopenaeus vannamei), other shrimp, and krill. Moreover, semi-quantitative reverse transcriptional polymerase chain reaction (PCR) was carried out to analyze the expression pattern and distribution profiles of the trypsins after they were subjected for bacterial and viral challenge. The results showed that in the transcriptional level, these trypsins were upregulated in hepatopancreas after they were infected with bacteria and virus. Therefore, these trypsins might be involved in the innate defense reactions manifested by Chinese shrimp.