Comparative Study On The Different Strains Of Mizuhopecten Yessoensis Response To High Temperature

Mizuhopecten yessoensis is one of the most important cultured species in the northern coastal area of China because of its individual,delicious taste,rich nutrition.In recent years,the death rate of M.yessoensis in summer was more and more serious,which caused huge economic losses to the aquaculture industry.In this study,M.yessoensis with brown shell(Control group)and white shell(Ivory white strain)was used for experimental materials,the response of physiological metabolism,immune enzyme activity and gill tissue structure to high temperature of different shell-colored M.yessoensis were studied by combination of laboratory simulation and sampling in natural sea area.At the same time,the differences in proteomic expression between M.yessoensis were studied under high temperature fluctuations.The following results have been obtained:1.The effects of acute high temperature stress on survival,immune enzyme activity and gill tissue structure of different shell-colored M.yessoensis were studied by simulating high temperature(26?)seawater in the laboratory.With the prolongation of stress time,the death rate of brown shell M.yessoensis was 3.92% after 9 hours of stress,which was significantly higher than that of white one(P > 0.05);after 12 hours of stress,the death rate of brown shell was higher than that of white shell.At the same time,the CAT,SOD,T-AOC and LZM of brown shell were significantly changed after high temperature(P < 0.05),but the T-AOC of white shell doesn't show any significantly change.In addition,the gill structure under high temperature had a significant transformation.The thickness of gill lamella,the width of gill filament and the distance between gill filament decreased with the increase of temperature,while the gill cavity and the distance between gill lamella increased.2.A new cycle mode of high temperature fluctuation was designed: 20??23??26??23??20?(range of temperature change 0.5? / h),3 groups of brown shell M.yessoensis and 3 groups of white(n = 3)were stressed,and a normal temperature control group of each kinds of shell-colored was set,experimental period is 7 days.On the 5th and 7th day of the experiment,there were 1 dead individual in each brown groups,and no death in white groups.During the period of temperature fluctuation,the activity of CAT in gill tissue of two kinds of shell-colored decreased significantly(P < 0.05),and returned to the level of control group at the end of the experiment.The activity of SOD in gill tissue of brown groups decreased significantly(P < 0.05),then fluctuated and finally returned to control group level,while did not decrease significantly(P > 0.05)in white groups.During the period of temperature fluctuation,the activity of SOD in the gill tissue of white groups was always higher than that of control group,and returned to same level after the fluctuation.The variation trend of T-AOC in two shell-colored groups is the same,the variation range of T-AOC in white groups is smaller than that in brown.The LZM activity changed significantly(P < 0.05).3.The common scallops and "ivory white" scallops are hoisted in the sea area of the second beach of Zhangzidao,and the wild area sampling is carried out regularly during the high temperature period in summer.the immune enzyme activity and gill tissue structure were compared and analyzed in different high temperature period.According to immune enzyme activity,two kinds of shell-colored M.yessoensis showed similar tendencies of increasing at first and then decreasing,the difference was significant(P < 0.05).However,enzyme activity level of white M.yessoensis was higher than that of brown,in August.The microstructure of different shell-colored M.yessoensis gill tissues were observed.With the prolongation of high temperature period in summer,the thickness of the gill lamella,the width of the gill filament and the distance between the gill filament decreased significantly while the gill cavity and the distance between gill lamella increased.4.Gill tissue proteins of two shell-colored M.yessoensis with different levels of high temperature stress were isolated by SDS-PAGE electrophoresis.GO analysis indicates that proteins are mainly enriched in cellular processes,metabolic processes,single biological processes,Using LC-MS/MS mass spectrometry to identify those screened differentially expressed proteins,and divided into the following 5 categories according to their function: Heat-shock protein,Cytoskeleton protein,Cellular biological functional protein,Signaling pathway regulatory protein and ATP synthase.The proteins related to this research were further screened,including ATP synthase,Interferon inducible protein,Gelsolin,Protein disulfide-isomeraseA3(PDIA3)and ?-tubulin.