中文摘要：

为研究解淀粉芽孢杆菌X-278菌株所产抗菌蛋白的性质,通过饱和硫酸铵沉淀法提取X-278菌株蛋白粗提液,并对蛋白粗提液进行蛋白酶稳定性试验和热稳定性试验。结果表明,当硫酸铵饱和度为50%时,沉淀得到的X-278菌株蛋白粗提液对棉花黄萎病菌的抑菌作用最强,抑菌圈直径达18.9mm。蛋白粗提液对蛋白酶K敏感性最差,对胰蛋白酶最敏感;蛋白粗提液经40℃处理后抑菌活性最高,而121℃处理后抑菌活性最低,抑菌圈直径为13.6mm,为对照（常温处理）的72%。以上结果表明,X-278菌株粗蛋白的部分抗菌成分属于耐热物质,并且抗菌成分间存在性质上的差异。

英文摘要：

In order to study the characteristics of antifungal proteins isolated from Bacillus amyloliquefaciens X-278, crude proteins were extracted via precipitation of the cell culture of strain X-278 with ammonium sulphate,and the protease stability and thermal stability were deter- mined. The result showed that the crude proteins of strain X-278 had strongest control effect on cotton Verticillium wilt using ammonium sulphate at 50% saturation, with the inhibition zone diameter of 18.9 mm. The crude protein extracts were relatively insensitive to proteinase K,but more sensitive to trypsin. The activity of the antifungal substrates was investigated under diffe- rent temperatures,and the result showed that the antifungal activity at 40 ＂C was the highest, while it decreased most at 121 ＂（2 and showed significant difference from the control. However,the crude protein extracts still retained 72 % of the antifungal activity compared to the control and the diame- ter of inhibition zone was 13.6 mm after heat treatment for 30 min under 121%. The results above indi- cated that part of the antifungal extracts of Bacillus amyloliquefaciens X-278 were heat-resistant sub- stance and the antifungal extracts were several substrates with different traits.