Analyse The Production Of V.parahaemolyticus Virulence Factors Influenced By Shrimp Dominated Spoilage Organisms Based On Quorum Sensing

Shrimp dominated spoilage organisms was produced by corruption shrimp mince and could cause shrimp corruption. 10 strains of shrimp dominated spoilage organisms were tested for the production of AHLs and AI-2 quorum sensing signal molecules termed autoinducer. Then, three organisms which can produce high production of AHLs or AI-2organisms were selected respectively. Finally, Vibrio parahaemolyticus was influenced by them with results of growth density, biofilm formation, hemolysis and production of signal molecules were researched.1. The shrimp dominated spoilage organisms as the research object, the special spoilage bacterium of high production AHLs or AI-2 were selected after all strains were qualitative and quantitative detected. And then activity changes of signal melocular of selected strains were detected. The results shows that the results of qualitative detection used by a bioassay JZA1 was induced by AHLs from spoilage bacterium extracts shows a great differences, high biologic specificity, and low sensitivity. Beta-galactosidase semi-quantitative method detects AHLs shows a few differences and be suitable for qualitative and quantitative detection of AHLs of spoilage bacterium. The results of qualitative and quantitative detection used by a bioassay BB170 was induced by AI-2 from spoilage bacterium extracts shows stable. The production of AHLs and AI-2 were related to cells density and activity of strains. AHLs gradually accumulate with bacteria growing and keep the highest production against cell in its steady state. Besides, AI-2 gradually accumulate with bacteria growing in beginning steady state and sharply decrease in later. It is showed that AHLs and AI-2 of shrimp dominated spoilage organisms are quite different.Both of AHLs and AI-2 produced a high production in 18~24h, and then AHLs production was kept stablely but AI-2 production be decreased quickly.2. To research the influence of biofilm formation and signal molecular production of V. para affected by spoilage bacterium, cell density, biofilm formation and production of signal molecular of V. para changed in different influence were studied. The results shows that biofilm formation of V. para was increased both by cells and extracts from supernate of spoilage bacterium.And spoilage supernate is better. Biofilm of V. para was formatted more after 48 h than 24 h. On the other hand, growth of V. para could be inhibit by extractsand based on this phenomenon signal molecular of AHLs and AI-2 production from V. para been increased either. Such characteristics of V. para degree deepen with the addition of spoilage bacterium supernate in low dosage. Without of a low dosage, biofilm formation and production of AHLs and AI-2 sharply decreased due to a severe inhibition of cells density. It is concluded that positive effect of addition to biofilm formation, production of AHLs and AI-2 are 0%~0.12%, 0%~0.1%, and 0%~0.08% respectively. Adjustment period of V. para cell density was sensitively influenced by extracts and lightly influenced in latter growth period. Biofilm and AI-2 of V. para were sensitively influenced by extracts in adjustment period and before and lightly influenced in latter growth period. Influence of AHLs was gradually strengthened through whole growth in 24 h. It is showed that metabolites and cell growth of V. para had different sensitivities as a response to exogenous additions in various growth period of itself.3. The influence of hemolysis activity and thermostable direct hemolysin(TDH)expression of V. para affected by spoilage bacterium as the research object, cell density,hemolysis activity of V. para and tdh expression of ATCC33847 changed in different effects were studied.The results shows that hemolysis activity and cell density were changed either by cells or by extracts of spoilage bacterium. Hemolysis activity of V. para influenced unobvious by cells,but obvious change by extracts. Bacteria camtF had the greatest impact to hemolysis of tested V. para and could increase twice activity of it.Growth of V. para was inhibited by cells of spoilage bacterium,from those the camtE,camtF, camtG showed superiorities as a result of 10.6%, 16.6%, 13.8% agnist the original growth of ATCC33847. However, growth of V. para was inhibited seriously by extracts of spoilage bacterium and only 23% of the original growth of V. para was affected by camtE.Hemolysis activity of V. para in 12 h from total growing period was sensitively increased by extracts and improved 3.54 times. Extract of camtF had a stronger influence to tdh expression of ATCC33847 than its cell and increased more than ten thousands times of former. It is showed that hemolysis activity and tdh expression of V. para were much sensitively influenced by extracts of spoilage bacterium and hemolysis activity increased greatly depending on adding extracts in early stage of logarithm. ATCC33847 has the most harmful to liver, kidney, lungs and stomach of mice than other organs. Supernate extract of camtF can strengthen this damage effect possibility.