The Immunological Characters And Pathogenic Study Of Cultured Apostichopus Japonicus

Sea cucumber, Apostichopus japonicus Selenka, is one of the most favorite sea foods in Asia. Its farming becomes a fast growing aquaculture industry in China. However, due to limited knowledge on its biological characteristics, sea cucumber has suffered serious diseases from large-scale and high-density culturing. In the challenge of the holothurian diseases happening in the recent years, it was essential to beat up its immune mechanism to probe into effective methods avoiding diseases. The peroxidase (POD), nonspecific esterase (NSE),acid phosphatase (ACP) and alkaline phosphatase(AKP) of several apparatuses were studied by histochemistrical localization method. The results showed that the POD existed in the tentacles, respiratory tree and digestive system of Apostichopus japonicus. The activity of POD in epidermic layer of body wall and the outer layer of alimentary canal were weakly positive(+). POD in epidermis of tentacles were positive(++). POD in peritoneal layer and nether peritoneal layer of respiratory tree were strong positive(+++). A lots of POD positive granules were excreted in the esophagus and stomach. The activities of NSE of all epidermis of holoturian apparatuses were strong positive, especial in the outer layers attaching to sea. The AKP presented in epidermic layer of tentacles and papillate podia, the peritoneal layer and nether peritoneal layer of respiratory tree, and the peritoneal layer of digestive system. The activities of epidermic layer of tentacles and peritoneal layer of respiratory tree were positive.A kind of virus particles were observed in cytoplasm of sampled ill sea cucumber tissues which were sampled from sick sea cucumbers with ulcerous skin and swollen mouth from their farming ponds at the beginning of 2005. The particles were covered with a bilayer envelops, shaped in globular with its size 100-200 nm in diameter. The same virus was isolated from cultured sea cucumbers with disease from different time and sites, and then infected the healthy sea cucumber. sea cucumber appeared the phenomenon such as ulcerous skin and swollen mouth and the same virus was isolated from infected sea cucumbers.Immunostimulants may improve disease resistance of aquatic invertebrates by priming innate defense response of a host. By the use of spectrophotometry, five saccharides were screened, including chitosan, yeast polysaccharide, seaweed polysaccharides, burdock oligosaccharide and lentinus edodes polysaccharide, for the potential of being immunostimulants. The saccharides were injected into sea cucumbers Apostichopus japonicus (selenka) and activities of lysozyme(LSZ) and superoxide dismutase(SOD) in its coelomic fluid and slime were monitored in 6 consecutive days post injection. The results showed all of the five saccharides could enhanced the activity of LSZ and SOD in coelomic fluid 4 days after injection (P<0.05). The activities of LSZ and SOD activities of slime with significant elevations were caused by these saccharides 2 days after injection.A perfect database should have enough capability to store every possible linear single strain DNA sequence (LssDNA )and its sequences could be represented precisely and visible. At the present time algebraical method and geometrical method which were presenting LssDNA s by letter-series and curves respectively. Each of the two methods had some of the limitations and disadvantages that are possible reasons of their coexistent. This article supposed a novel idea of building a new kind of (LssDNA ) database by unifying algebraical method and geometrical method. Each LssDNA was presented by a dot on a natural number coordinates axes, then the database was termed by'DotBank'.