Study On The Pathogenicity About Vibrio Parahaemolyticus To Coelomactra Antiquata And Its Outer Membrane Protein

Vibrio parahaemolyticus (Vp) is gram negative halophilic,leading to some diseases, high incidence, prevalence wide range, serious damage. Vibrio disease is one of the most mainly factors to restrict on shellfish and other marine fish in China's marine economy development of animal breeding industry. There are many related reports for fish, but few for shellfish.Invertebrates such as the bivalve Coelomactra antiquata have no immunoglobulin , lacking specific immune response that mediated by antibody. Researches show that suitable immunity stimulation can enhance ability of non specific immunity of biological mechanism, improving its whole function of disease resistance.Outer membrane protein(OMP) is one of the effective antigen in the bacterial surface. The vaccine made of OMP could protect body resisting infect of homotype or heterotype bacteria. Its immunogenicity and inducing protective immune response have been proved. With modern biotechnology extracting OMP easily,there is wide prospect to developing OMP vaccine.Study on the monitor of resistance and the resistance mechanism have became very active world wide subject. Researching resistance for many bacteria to antibiotics,can provide scientific basis for resistance monitor and control of bacterial diseases.In view of this, in this experiment, C. antiquata was artificial infected by V.parahaemolyticus,successive observation seven days,we knowed Vp have very strong pathogenicity to C. antiquate and mortality rate increased with infective dose adding. The appearance of pathological changes is significant. Take the intestinal, foot, outlet pipes, gonad and pallium to paraffin section observations, there were pathological features in various parts in varying degrees, in particular, significant changes in epithelial cells.With Sarcosine sodium dodecyl extracting VP-OMP, SDS-PAGE analyzing protein molecular weight, Bradford determining concentrations of OMP ,found that different culture conditions temperature, pH, culture medium the VP-OMP had different effects on ; Culture time had no effect on VP-OMP.Afetr immuning C. antiquata with VP-OMP and artificial infection, the continuous observation in 14 days, found the rate of immune protection of OMP was higher than that of the whole-cell inactivated vaccine and the protective rate of high concentration OMP for the bivalve was higer than the low. The immune indicators such as antibacterial activity bacteriolytic activity and phagocytic activity had improved to varying degrees.Through the test of drug sensitivity to the bacteria V. parahaemolyticus, V. anguillarum, V. mimicus, V. alginolyticus,Aeromonas hydrophila, Staphylococcus aureus, E. coli on the 30 kinds of antibiotics, the results were found that different antibiotics for different bacteria have different levels of resistance.To sum up,study on the pathogenicity about Vibrio parahaemolyticus to Coelomactra antiquate, SDS-PAGE analysis of extracted OMP in different culture conditions, non-specific immunity about VP-OMP for Coelomactra antiquata initial and drug-sensitive test of seven kinds of bacteria, provided a theoretical basis for pathology on bacterial diseases of Valuable shellfish, OMP vaccine research non-specific immunity of shellfish and monitoring of drug resistance.