| This study investigate a kind of epidemic disease——"yellow water"disease which broke out in the cultured Scylla sarrata along the coastal area of Zhejaing province,China in these years.The mian symptoms of the diseased crab display as following:yellow water could be seen under carapace,hemolymph turned into yellow or turbid white liquid which can't coagulated.The disease caused serious loss because of its long duration,and it shows a seasonal epidemic trend now.In order to learn more about the pathogenesis of the disease,we survey and evaluate the immunization levels and measured blood parameters of diseased crabs,and carry out a exploratory reseach about the mRNA differential displays in hepatopancreas from diseased crabs which coerced by"yellow water"disease.The main results of our study are as followings:1. Classified the hemocytes of Scylla serrata into three categoriesUse the hemolymph of healthy crab as studied material, and observated it microscopically and submicroscopically.We classified the hemocytes of Scylla serrata into three categories: semigranular cell(SGC),granular cell(GC) and hyaline cell(HC),these three kinds of hemocytes show significantly differences microscopic and submacroscopic structures.Classification of the hemocytes can provide the theory premise for the analysis of the changes in the hemocyte proportion.2.The impact of"yellow water"disease on the immunization levels of scally serrata.Chosed total hemocyte count(THC),hemocyte proportion,the phagocytosis activity of hemocytes,ACP, AKP, LZM, POD, SOD, PO activity in serum as indicators,measuered and compared the immunization levels of crab with"yellow water"disease and controls,and discoverd that most of the indicators showed significantly changes,the THC,hemocyte and phagocytosis activity and enzyme activity in serum decreased significantly,the proportion of different hemocytes also changed significantly.All these indicated that after contracting"yellow water"disease,the capacity of immunity was inhibited,the immunity system suffered damage,and the possibility of contracting secondary infection would increase.3.Blood biochemistry analysis of"yellow water"disease in Scylla serrata.Compared to healthy crabs,most of the blood biochemical parameters of the diseased ones changed significantly.The protein content and enzyme activity in serum decreased significantly,the metabolites contents of carbohydrate/lipid/protein in serum is abnormal,and electrolyte in serum imbalanced.These indicated that,the capacity of digestion/absorption/excretion and Osmoregulation had been damaged,and the organs associated with these function had serious lesion.4.mRNA differential displays in hepatopancreas of crabs with"yellow water"disease and controls.Adopt the methold of molecular pathology and study the pathological changes in the hepatopancreas of crabs with"yellow water"disease.Using the mRNA differential display technology,we discovered the exist of differential displayed genes in diseased crabs and healthy ones.Amplificated the genes of hepatopancreas from different crabs using PCR technology,and compared the PCR product using PAGE. At least 10 differential displayed strips were discovered,and two of them wre recycled and reamplificated successfully:one from healthy crabs and another from diseased crabs,which were thought to be the fragments of differential diaplayed genes.Cloned and sequenced the two gene fragments,blasted the results in GenBank,and no similar gene were found,thought that they may be new genes which were respectively displayed in healthy crabs and diseased crabs,they were opened or closed in different physiological states.The changes happened in micro-molecular level lead the changes of metabolism in macro-tissues,and revealed the pathological changes on molecular level,and this study can also provide new ideas in pathological reseach. |
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