| Summary: | 碩士 === 東吳大學 === 微生物學系 === 89 === For crustaceans, hemocytes constitute mainly the primary defense mechanism against the pathogenic infections. Recent reports showed that hemocytes phagocytic ability could be increased by lectins. However, some environmental hormones will induce adverse health effects in aquaculture, including abnormal sexual differentiation, impair reproductive development, and immunosuppression etc.
The aim of this study was to investigate the effects and virulence of lectins, phthalate esters and bactericidin on hemocytes of giant freshwater prawn (M. rosenbergii). We used immunofluorescence stain to screen fourteen lectins, and found four lectins, which are Concanavalin A (Con A)、Pisum Sativum agglutinin (PSA)、Jacalin and Wheat germ agglutinin (WGA), can labeled on hemocytes. Further analysis with flow cytometry shows that four lectins can labeled on all hemocytes. In oreder to investigate effects on cell adhension and pseudopodia stretching ability, an in vitro exposure experiments was used. Hemocytes were separately treated with four lectins, eight phthalate esters (PAEs) and a bactericidin. The result of lectins shows that Jacalin would decrease the percentage of adhensive cells (10﹪). PSA would inhibit cell pseudopodia stretching ability (41﹪). In PAEs, DRP (dipropyl phthalate) and DEP (diethyl phthalate) not only decrease the percentages of adhesive cells (50﹪and 67﹪), but also increase pseudopodia stretching ability (33﹪and 30﹪). DHP (dihexyl phthalate) would decrease the percentage of adhesive cells (15﹪) and inhibit pseudopodia stretching ability (23.6﹪). DPP (diphenyl phthalate) and would inhibit pseudopodia stretching ability (32﹪). Bactericidin could increase the percentage of adhensive cells (13﹪). Mean while, microscopy examinations showed that DRP, DHP and bactericide altered morphology of cell nucleus and led to the presence of vacuoles in cytosol of hemocytes. Through membrane phosphatidyserine staining and analysis of DNA fragmentation, the results showed that hemocytes exposed to bactericidine and some PAEs such as DRP and DHP for more than 10 min would die of apoptosis. According to these results, we suggest that bactericidin have a two-edge effects on defense effects of prawn, existing of these PAEs in environment may affect the defense mechanism of prawn.
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