采用双层平板法从婴儿粪便中筛选出一株对烟曲霉具有抑制作用的菌株,通过形态学、生理生化特性及16S rDNA序列同源性分析,鉴定该菌株为副干酪乳杆菌(Lactobacillus paracasei),命名为LZ54.分别经pH、蛋白酶、XAD-2大孔树脂处理该菌株发酵液上清后,发现LZ54发酵液在酸性条件下具有较强的抗烟曲霉活性,但在碱性条件下其抑菌物质迅速失活；发酵液上清经胃蛋白酶、胰蛋白酶、蛋白酶K处理后失去部分抑菌活性,表明该菌株发酵液中抗烟曲霉的物质具有蛋白质属性；发酵液经XAD-2大孔树脂处理后仍具有抑制烟曲霉活性,并通过SDS-PAGE方法测得该抑菌物质的分子量约为5 kD.%A strain with strong inhibitory activity against Aspergillus fumigatus named as LZ54, was isolated from the feces of infants by the overlay plate method. The strain was identified as Lactobacillus paracasei by physiological and biochemical characterization and 16S rDNA sequence nomology analysis. Some antimircrobial substances exist in the cell-free fermentation supernatant were dealt with pH, enzymatic, Amberlite XAD-2 macroporous resin, and it was observed the antifungal activity was high at the neutral acid pH, but the antifungal activity decreased rapidly with the increase of pH. After enzymatic treatment of supernatant with pepsase, trypsin and proteinase K, loss of part of the antifungal activity was observed, which indicated there were other proteinaceous substance with the antifungal activity. After dealing with the XAD-2, the supernatant possessed the ability to inhibit Aspergillus fumigatus as well, and the molecular weight of the antimicrobial substance was about 5 kD determined by the SDS-PAGE.
展开▼
