Donatti Ariane C, Furlaneto-Maia Luciana, Fungaro Maria Helena P, Furlaneto Márcia C
Centro de Ciências Biológicas, Universidade Estadual de Londrina, PO Box 6001, 86051-990 Londrina-PR, Brazil.
Curr Microbiol. 2008 Mar;56(3):256-60. doi: 10.1007/s00284-007-9071-y. Epub 2007 Dec 11.
Extracellular proteases have been shown to be virulence factors in fungal pathogenicity toward insects. We examined the production of extracellular proteases, subtilisin-like activity (Pr1) and trypsin-like activity (Pr2), by Beauveria bassiana CG425, which is a fungus of interest for control of the grasshopper Rhammatocerus schistocercoides. To access the role of these proteases during infection of R. schistocercoides, we analyzed their secretion during fungus growth either in nitrate-medium or in cuticle-containing medium supplemented with different amino acids. The enhancing effect of cuticle on Pr1 and Pr2 production suggests that these protease types may be specifically induced by components of the grasshopper cuticle. In medium supplemented with methionine a high level of Pr1 was observed. The remaining amino acids tested did not induce the protease to the levels seen with cuticle. The amino acid methionine seems to play a regulatory role in Pr1 secretion by B. bassiana, since both induction and repression seem to be dependent on the concentration of the amino acid present in the culture medium.
细胞外蛋白酶已被证明是真菌对昆虫致病的毒力因子。我们检测了球孢白僵菌CG425产生细胞外蛋白酶、枯草杆菌蛋白酶样活性（Pr1）和胰蛋白酶样活性（Pr2）的情况，该真菌是防治蝗虫Schistocerca schistocercoides的研究对象。为了探究这些蛋白酶在感染Schistocerca schistocercoides过程中的作用，我们分析了它们在真菌于硝酸盐培养基或添加不同氨基酸的含表皮培养基中生长时的分泌情况。表皮对Pr1和Pr2产生的增强作用表明，这些蛋白酶类型可能由蝗虫表皮成分特异性诱导。在添加甲硫氨酸的培养基中观察到高水平的Pr1。所测试的其余氨基酸均未将蛋白酶诱导至表皮所呈现的水平。甲硫氨酸似乎在球孢白僵菌Pr1分泌中起调节作用，因为诱导和抑制似乎都取决于培养基中该氨基酸的浓度。
