Clearing mechanisms of Vibrio vulnificus biotype I in the black tiger shrimp Penaeus monodon

Diseases of Aquatic Organisms

V. Alday-Sanz¹  J. F. Turnbull¹  A. Roque¹ 

关键词: Shrimp;    Vibrio · Penaeus monodon;   

DOI  :  10.3354/dao048091

学科分类：生物科学（综合）

来源: Inter-Research

【 摘 要 】

ABSTRACT: Vibrio species¹ infections are a common sequelae to environmental stress or other disease processes in shrimp, but the mechanism by which the shrimp eliminate the bacteria is poorly understood. In this study, the penetration, fate and theclearing of V. vulnificus were investigated in Penaeus monodon. A bacterial disease isolate from a shrimp farm was identified as V. vulnificus biotype I. Polyclonal antiserum was raised in rabbits against the bacterium and thespecificity was verified by ELISA and immunoblot against a range of Vibrio spp. and other Gram-negative bacteria. The bacteria were then administered to P. monodon juveniles by injection, immersion and oral intubation. An indirectimmunoperoxidase technique was employed in a time course study to follow the bacteria and bacterial antigens in the tissue of the shrimp. Bacteria were cleared by a common route, regardless of the method of administration. Observations in immersionchallenge were similar to a combination of those for oral and injection challenges. With immersion, bacteria entered the shrimp through damaged cuticle or via insertion points of cuticular setae. Shortly after entry, whole bacterial cells were observed inthe haemolymph and connective tissue. They were either phagocytosed by haemocytes, or broken down outside host cells. Haemocytes containing bacterial cells or antigens (HCB) were observed in the connective tissue and haemolymph. HCB accumulated aroundthe hepatopancreas, midgut, midgut-caecum, gills, heart and lymphoid organ. Free bacterial antigens also accumulated in the heart and lymphoid organ. Bacteria entering through the mouth by oral intubation or immersion were broken down so that only solubleor very fine particles entered the hepatopancreas. Bacterial antigens passed through the hepatopancreas into the haemolymph. Antigens were initially observed in the haemolymph sinuses and subsequently accumulated in the heart and lymphoid organ.Bacterial antigens were released from the shrimp, initially through the gills and subsequently through hepatopancreatic B-cells, branchial podocytes and sub-cuticular podocytes.

【 授权许可】

Unknown