少孢节丛孢菌(Arthrobotrys oligospora)表面聚合物的提取及生化性质研究

Studies on Extraction and Biochemical Characters of Surface Polymers on Traps of Nematode-trapping Fungus—Arthrobotrys oligospora

为了解捕食线虫性真菌——少孢节丛孢菌(Arthrobotrys oligospora)捕食器表面聚合物的生化性质与作用,用5mol·L-1LiCl的表面聚合物提取液提取位于捕食器表面的这类物质,进而测定其中蛋白质的含量与酶的活性,并详细研究了温度、pH、化学试剂和蛋白酶抑制剂对其性质的影响。结果表明:2种不同来源的表面聚合物[表面聚合物(T+)与表面聚合物(T-)]最适温度均为65℃,前者最适pH为7.0,后者最适pH范围为6.5～7.5,且前者大相对分子质量蛋白质的浓度相对后者要高;同时还首次在含捕食器菌丝提取到的表面聚合物中检测到了蛋白酶、酸性磷酸酶和碱性磷酸酶的活性。通过研究初步了解了存在于捕食器表面并参与捕食过程的蛋白质类物质的相关化学性质,间接证实了上述物质可能在捕食过程中起关键作用,为今后深入开展对捕食线虫性真菌作用机理方面的研究提供了非常有价值的资料。

This experiment was conducted to study the biochemical characters and effects of surface polymers from the nematode-trapping fungi,Arthrobotrys oligospora.The surface polymers were extracted by optimized method with 5 mol·L-1 LiCl,then proteins concentration,enzyme activity and toxicity of the surface polymers to nematodes in vitro were determined.Meanwhile,the effects of temperature,pH,chemical reagents and protease inhibitors on the surface polymers were also studied.The result showed that the protein contents and protease activity of the surface polymers from mycelium with traps was significantly higher than that from general nutrition mycelium and protease,acid phosphatase and alkaline phosphatase were detected for the first time.The optimal temperature was 65 ℃ for both polymers.The optimal pH were 7.0 and 6.5-7.5,respectively.They both had low toxity to nematodes tested.All above results indirectly confirmed the effects of surface polymers on the preying process,and a preliminary understanding of composition and biochemical characters of the surface polymers were carried out.It also provided valuable information for the studies on the mechanism of nematode-trapping fungi in future.