抗真菌多肽APS—1的分离纯化与特性

蜡状芽孢杆菌（Ｂａｃｉｌｕｓｃｅｒｅｕｓ）Ｓ１菌株对多种作物真菌性病害有良好的防效。本文报道了Ｓ１菌株产生的抗真菌物质的纯化及其部分特性。该菌株的发酵液经过酸沉淀和有机溶剂抽提、ＳｅｐｈａｄｅｘＧ１００与ＤＥＡＥ５２柱层析等步骤后，抗真菌物质得到纯化，硅胶薄层层析显色为单点。该物质在２７５ｎｍ处有吸收峰，对蛋白酶有一定耐受性，茚三酮反应呈阴性，但酸水解后，茚三酮反应呈阳性，双缩脲反应也呈阳性。氨基酸组分分析结果表明，该物质由谷氨酸、天门冬氨酸、酪氨酸、丝氨酸、苏氨酸、脯氨酸、亮氨酸、异亮氨酸、缬氨酸和一种异常氨基酸组成。推测该物质为一种环状多肽，命名为ＡＰＳ１。紫外光照射和高压灭菌处理后，ＡＰＳ１的抗真菌活性损失不大。平板抑菌试验结果表明，ＡＰＳ１对９种供试真菌的孢子萌发有抑制作用，其完全抑制浓度因真菌种类不同而有差异

PURIFICATION AND CHARACTERIZATION OF A NOVEL ANTIFUNGAL PEPTIDE APS 1 PRODUCED BY BACILLUS CEREUS

In previous study, we isolated an antagonist Baci llus cereus strain: S 1 from cotton plant. In field experiments, this bacterium was shown strong inhibition to several plant diseases. In this paper, we reported the purification of the antifungal substance produced by the bacterium and its properities. After the steps of acid precipitation, methanol and ethy lether extraction, Sephadex G100 and DEAE52 column chromatography, the antifungal material was purified. The purified material had absorption peak at 275nm, and was exhibited negative in biuret color reaction. However after hydrolyzed with HCl, this substance shown positive in the same reaction. Amino acid analysis to the hydrolysate of APS 1 showed that APS 1 was composed of Glu, Asp, Tyr, Ser, Thr, Pro, Leu, Ile, Val and an unknown amino acid. Combining with its pratial resistance to proteinases, it was suggested that this antifungal material was a cyclic peptide. This peptide, named APS 1, with strong inhibition on the germination of spores of the phytopathogens tested, was shown high stability against ultraviolet radiation and heat. APS 1 may have potential role in plant diseases biological control.