Alternaria alternata菌丝细胞壁凝集素的纯化与特性研究(英文)

Purification and Characterization of a Lectin from the Fungus Alternaria alternata Mycelia Cell Walls

Alternariaalternata是接触性活体营养菌寄生真菌纤细齿梗孢Olpitrichumtenellum的寄主真菌之一,该寄生过程中菌寄生真菌与寄主真菌的识别机制未见报道。本文分离、纯化了A. alternata菌丝细胞壁上的一种参与识别作用的特异性蛋白———凝集素,并对其特性以及在菌寄生过程中的作用做了初步研究,粗提液经硫酸铵分级沉淀, DEAE-Sepharose阴离子交换柱层析和SephacrylS 100分子筛层析等步骤便可获得凝胶电泳均一的凝集素AAL, 经凝胶过滤层析法测得分子量为37. 2kDa, 经糖染色鉴定为一种糖蛋白。孢子凝集试验表明,AAL对O. tenellum的孢子具有极强的凝集力,在含量为3 325μg/mL时, 30min内90%的O. tenellum孢子发生凝集作用,对照(不含AAL的缓冲液)凝集力则显著下降。上述结果说明AAL在A.alternata细胞壁蛋白抽提液和O. tenellum的孢子吸附中扮演着重要角色,可能起识别因子的作用。

Alternaria alternata is one of the host fungi of Olpitrichum tenellum, which is a biotrophic contact mycoparasite. The recognition mechanism between them has not been reported. This research focused on the purification, and characterization of a lectin isolated from A. alternata mycelial cell walls, in order to reveal the recognition mechanism between mycoparasite and mycohost. The A. alternata lectin, abbreviated to AAL, was purified using ammonium sulfate fraction, DEAE-Sepharose Fast Flow chromatography and Sephacryl S-100 chromatography. AAL is a glycoprotein with an apparent molecular weight 37.2 kDa as determined by gel filtration, and may be a recognition molecule which mediates the adhesion of O.tenellum cells to A.alternata cells. From adhesion experiments between AAL and conidia of O.tenellum, >90% of conidia adhered within 30 min at concentrations as low as 3.325 μg/mL. The control has no significant effect on spore adhesion.