Coloning Of Immunogene And Immune Responses After Co-infection In Litopenaeus Vannamei

Currently, aquaculture suffer severe eutrophication, and the healthy development of shrimp farming industry is seriously threstened by farming water environmental deterioration and shrimp disease. White spot syndrome virus was characterized by highly contagious and high mortality rates to shrimp, it had become one of the most serious shrimp disease in the world. What methods and means adopted to prevent and control WSSV outbreak, had become one of the hot areas of aquatic diseases research. In this study, we investigated the death of shrimp and immune response under pathogen complex infection, in order to provide a theoretical basis for the prevention and control of aquatic diseases.(1) In this study, we cloned evolutionarily conserved signaling intermediate in Toll pathways gene of Litopenaeus vannamei. The complementary cDNA of LvEcsit 1 was 1483 bp, encoded 311 amino acids. It showed highly homology with ECSIT of Marsupenaeus japonicus, followed by insects and farthest evolutionary distances with mollusk such as oysters and mussels. LvECSIT mRNA expressed in all detected tissues, with the most expression in the hepatopancreas, intestine and gill tissues. The expression LvECSIT mRNA did not significant different with WSSV single infection. It could be stimulated to express under V. parahaemolyticus and WSSV co-infection condition, and the expression levels of co-infection group was always higher than WSSV single infection group.(2) In this study, we cloned focal adhesion kinase(Lv FAK) gene of Litopenaeus vannamei, the full length of LvFAK c DNA was 4919 bp, and encoded 1012 amino acids. It showed the most highly homology with FAK of Marsupenaeus japonicus, with 96 % similarity. It did not have the character of specific tissue distribution, with the most highly expression in eyes, and the least expression in muscle. It could be activated by WSSV single infection, V. parahaemolyticus single infection and co-infection.(3) In this studied, the index such as mortality of Litopenaeus vannamei after they had been injected with the bacteria V. parahaemolyticus and the WSSV was examined under 26 ℃ culture condition. The results showed that the mortality of co-infection group was significantly less than WSSV single infection group, the mortality fo vibrio single infection group was the least in all treatments. The mount of WSSV in co-infection group was always higher 10 times than WSSV single infection group. The ACP, AKP, POD, SOD activity of gills, hepatopancreas and muscle tissues in co-infection group was higher than WSSV single infection group. Vibrio infection could induce the activity of ACP, AKP, POD, SOD.