[Isolation and purification and toxigenic characteristic identification of microcystis].

OBJECTIVE: To establish methods of isolation and purification of microcystis, and to identify it's biological property. METHODS: By the means of 96 well microplates and utmost dilution, microcystis was isolated and purified from Xiliu Lake of Zhengzhou. Absorbency of isolated microcystis was determined by visble light spectrophotometric method, and it's growth curve was ploted, calculated growth rate constant and double time. Toxigenicity of isolated microcystis was identified by means of the Whole cell PCR and ELISA, and the concentration of microcystin in crude extractive solution from freeze-dried microcystis cells was determined by ELISA. RESULTS: Two strains of microcystis, Microcystis XLH6 and Microcystis XLH10 were isolated successfully from Xiliu Lake. Their growth curves were "S" style, their growth rate constants rapidly ascended firstly, and then slowly descended. Average growth rate constants of the two strains were 0.294 and 0.345, average double times of the two strains were 82h and 70h, respectively. The results of the Whole cell PCR and ELISA of the two strains were positive, and both of them were toxigenic. Every milligram of freeze-dried Microcystis XLH6 and Microcystis XLH10 produced 1.4microg and 2.4microg microcystin. CONCLUSION: Xiliu Lake was polluted by toxigenic microcystis. 96 well microplates can be used to isolate microcystis.