Streptomyces alboflavus抗真菌物质对串珠镰刀菌的抑制机理研究

研究了Streptomyces alboflavus产生的抗真菌物质对串珠镰刀菌的抑菌机理。通过pH纸层析和捷克八溶剂纸层析实验对抗菌物质进行定性分析；利用荧光显微镜和扫描电子显微镜观察抗菌物质对串珠镰刀菌细胞膜和细胞壁的破坏作用；通过细胞膜和细胞壁主要组分对抑菌物质的拮抗效果,探索抑菌物质的作用靶点；用高效液相色谱法检测抑菌物质对串珠镰刀菌细胞膜中麦角甾醇的抑制作用。极性实验显示,该物质呈中性,捷克八溶剂纸层析表明,该物质属于非水溶性Ⅰ型抗生素；光学显微镜观察,抑菌物质对串珠镰刀菌孢子萌发有抑制作用,同时使菌丝畸形,顶端、中部出现膨大泡囊,呈“念珠状”；经PI染色后荧光显微镜观察,抗菌物质作用后的菌丝细胞膜通透性改变,进一步通过扫描电子显微镜观察,发现泡囊状菌丝表面凹凸不平,并残留有碎片；抑菌物质对细胞壁和细胞膜的组分拮抗作用和高效液相色谱方法检测显示,抑菌物质影响细胞膜中麦角甾醇的合成。研究结果表明,Streptomyces alboflavus产生的抗真菌物质发挥抑菌作用时,影响串珠镰刀菌细胞膜中麦角甾醇的合成。本研究可为抑菌物质的鉴定和拮抗菌的应用提供理论参考。

Inhibition Mechanism of Streptomyces alboflavus Antifungal Substance Against Fusarium moniliforme

The inhibition mechanism of antifungal substance generated by Streptomyces alboflavus against Fusarium moniliforme was investigated.The antifungal substance was qualitatively analyzed by pH paper and Doskochilova system chromatography. The destructive effects of antifungal substance on cell membrane and cell wall of Fusarium moniliforme were observed by fluorescence microscopy and scanning electron microscopy. The antagonistic effects of main components of cell membrane and wall on antifungal substance were explored. Furthermore, the inhibitory effect of antifungal substance on ergosterol in cell membrane of Fusarium moniliforme was detected by HPLC. The antifungal substance was neutral and non-water-soluble type I antibiotics by polarity test and Doskochilova system paper chromatography. Optical microscope was used to observe the inhibition of germination of Fusarium moniliforme spores, the mycelia were distortion, deformation and swelling when treated with the antifungal substance, and the fluorescence microscope revealed that the permeability of mycelial cell membrane was changed. Moreover, the results from scanning electron microscope showed that the surface of vesicular mycelia was uneven and fragments remained. The antagonism of antifungal substance effect on components of cell wall and cell membrane and the detection by HPLC showed that the synthesis of ergosterol in the cell membrane was affected by antifungal substance. The synthesis of ergosterol in the cell membrane of Fusarium moniliforme was affected by the antifungal substance produced by Streptomyces alboflavus. This study laid a theoretical foundation on the identification of antifungal substance and the application of antagonistic bacteria.