摘 要 ：分离得到一株对黄瓜菌核病菌Sclerotinia sclerotiorum (Lib.) de Bary有拮抗作用的枯草芽孢杆菌G8,其无菌发酵液经硫酸铵沉淀得广谱抗菌粗蛋白。为明确枯草芽孢杆菌G8的理化性质,研究了温度、pH变化、UV照射、有机溶剂、蛋白酶和保存时间对抗菌蛋白稳定性的影响。结果表明:此粗蛋白耐酸,在pH值1~10范围内均有抑菌活性,将其pH值调为1.0作用16h后保持原有活性的69.2%;对温度有较高的稳定性,抗菌蛋白经100℃处理60min保持原有活性的80.8%;对蛋白酶K和有机溶剂不敏感;抗菌粗蛋白抑菌活性持久,在常温下120天保持原有活性的71.54%。初步研究了抗菌粗蛋白对黄瓜菌核病菌的抑制作用。结果显示,病菌菌丝消融、原生质渗漏、菌丝细胞泡囊化,并抑制病菌菌核萌发。
Abstract:A Bacillus subtilis strain G8 which possesses antagonistic abilities to Sclerotinia sclerotiorum (Lib.) de Bary was isolated. The crude antifungal protein obtained by ammonium sulfate precipitation had broad inhibition spectrum. To gain valuable information for further purification, structure determination and exploitation of the antifungal protein, the effects of heat, pH, UV, organic solvents, proteinase and preservation time on inhibiting activity of antifungal protein were studied. The result showed that it was stable in various pH and temperature and resistant to proteinase K and organic solvents. The antifungal protein is active in the range of pH 1-10, even be adjusted at pH 1.0 for 16 hours, the inhibition rate on S.sclerotiorum was retained 69.2%. The antifungal activity was retained 80.8% after at 100℃ for 60min. The antifungal activity could lasting for long time at normal temperature and was retained 71.54% after preserving for 120d. Preliminary study on the action mechanism of the antifungal protein demonstrated that it could break down the hyphae and leak the protoplasm, turn the hyphal cells into bigger sacs and inhibit germination of Sclerotium sclerotiorum.