松材线虫携带一株荧光假单胞菌分泌毒素的初步研究

本文研究了离体情况下松材线虫携带的致病菌一株荧光假单胞菌(Pseudomonas fluorescens GcM5-1A)在LB、NB和PD三种培养基中的毒性, 以及产生的毒素对黑松(Pinus thunbergii)切根苗和悬浮细胞的效应。结果显示, 菌体在LB和NB 培养液的毒性较高, 其中 LB培养液的毒性最高, 且培养液的pH值为7时比pH值为5时毒性高, 而该菌在PD培养基中几乎不产毒。细菌培养液经硫酸铵分级沉淀, 得到了主要含有50 kDa蛋白的蛋白组分, 该蛋白组分对黑松悬浮细胞和切根苗均有较高的毒性, 并能改变黑松悬浮细胞细胞膜的透性, 导致胞内可溶性糖和游离氨基酸外渗。

Primary Study on the Toxins Secreted by Pseudomonas fluorescens Primary Study on the Toxins Secreted by Pseudomonas fluorescens

Pseudomonas fluorescens GcM5-1A carried by pine wood nematodes was cultured in LB, NB and PD medium. The cultures free of bacteria were used to analyze their toxicity to suspension cells and shoot seedlings of Pinus thunbergii. The cultures of LB and NB were toxic, with LB culture showing the highest toxicity, whereas almost no toxicity was detected for PD culture. pH values of the LB medium affected the toxicity of the final culture: the culture with an initial pH 7.0 was more toxic than one with pH 5.0. The proteins in the LB culture were precipitated by ammonium sulfate, and toxicity analysis showed the proteins toxic to both suspension cells and seedlings. As well, a component mainly containing a protein of 50 kDa, which also showed relatively strong toxicity, was partially purified on precipitation with ammonium sulfate of 20% saturation; treatment with the component could lead to leakage of soluble carbohydrates and free amino acids.