Breeding Strain Of Highly Producing Polysaccharides With Protoplasts Of Stropharia Rugoso-annulata And Studies On Its Antioxidative Activities

Stropharia rugoso-annulata (King Stropharia or Winecap) which belongs to Basidiomycota, Hymenomycetes, Agaricales, Strophariaceae, Stropharia, is a gorgeous, nutritional and functional mushroom with a pleasant refreshing taste of delicate fragrance, crisp and slightly sweet. Its fruitbodies contain high protein levels with all the essential amino acids and other elements, such as trace elements, vitamins and polysaccharides which have efficacy on preventing coronary heart diseases, helping to digesting and weakening mentally exhaustion. The inhibitory rates of polysaccharides of Stropharia rugoso-annulata to S-180 tumour in mice and Ai ascites cancer achieve 70 %.UV-irradiation protoplast mutagenesis is one of the effective breeding methods and it has been widely used until now. Edible and pharmaceutical fungal polysaccharides regarded as"biological response modifier"have become the focous of researches in many academic fields because of their special bioactivity.In this paper, we studied the conditions of protoplast preparation and regeneration from the mycelia of Stropharia rugoso-annulata. A Stropharia rugoso-annulata strain with high polysaccharides'production was obtained through UV-irradiation protoplast mutagenesis. The antioxidation effects of mutants and original strain of Stropharia rugoso-annulata were studied. The results were as follows:The highest yield of protoplasts(1.36×107/mL) can be obtained by using 1.5 % Lywallzyme made by 0.6 mol/L mannitol, digesting for 2.5 hours at the condition of 30℃and pH value 5.5. The optimal medium for protoplast regeneration of Stropharia rugoso-annulata was: potato 200 g, sucrose 20 g, peptone 2 g, yeast extracts 2 g, KH2PO41.5 g , K2HPO41.5 g , MgSO4?7H2O 1.5 g, vitamin B1 0.1 g, vitamin B6 0.1 g, distilled water 1 000 mL, ager 20 g, With above optimal regeneration medium containing 0.6 mol/L mannitol and two layer plating method, regeneration rate increased significantly and the highest regeneration rate was 0.96 %. The medium lethal dose of UV irradiation on Stropharia rugoso-annulata protoplasts was 20 s. According to antagonistic effect and state of growth, we screened 100 strains which polysaccharides'yield were higher than control. Finally, we screened strain 093 for its'high polysaccharides'yield and genetic stability. Content of polysaccharides of mutant 093 increased 25.3 % than that of original strain.The antioxidation effects on Glutathione peroxidsade (GSH-Px), Superoxide dismutase (SOD) and Malondialdehyde (MDA) of mutant 093 and original strain of the blood in intragastric rats were studied. The results showed that GSH-Px and SOD activities of the blood in intragastric rats with original strain and mutant 093 of Stropharia rugoso-annulata were increased, and concentration of MDA was decreased sharply. The antioxidation effect of mutant 093 of Stropharia rugoso-annulata was better than that of original strain.