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本文报道苏云金杆菌β-外毒素研究的结果。 从苏云金杆菌40个菌株(分属于9个血清型)中筛选出5个产β-外毒素的菌株:E-013(H_2)、Frc(H_1)、E-009(H_1)、E-096(H_7)和E-012(H_8)。 用家蝇(Musca vicina)三龄幼虫作生物测定,发现发酵液和菌粉水抽提液的致死中浓度(LC_(50))分别为原液稀释520倍和2,300倍,证明在我们的培养条件下,很易获得高浓度的β-外毒素,这对实际应用具有重要意义。此外,还研究了培养基种类和培养时间对β-外毒素产生的影响。 葡萄糖氧化酶对E-013菌株所产β-外毒素的活性有显著的抑制作用。 经过乙醇分级分离、钡盐沉淀和离子交换层析得到初步纯化的β-外毒素。紫外吸收光谱具有典型的腺嘌呤核苷酸类的特性:最大吸收波长(λ_(max))为258毫微米,最小吸收波长(λ_(min))为233毫微米。
This article reports the results of studies on the β-exotoxin of Bacillus thuringiensis. Five strains producing β-exotoxin were screened from 40 strains of Bacillus thuringiensis (belonging to 9 serotypes): E-013 (H_2), Frc (H_1), E-009 (H_1), E-096 H_7) and E-012 (H_8). The third-instar larvae of Musca vicina were used for bioassay. The lethal medium concentration (LC_ (50)) of the broth and the powdered water extract were respectively diluted by 520 and 2,300 times, respectively. It was proved that in our culture conditions , It is easy to obtain high concentration of β-exotoxin, which is of great significance for practical application. In addition, the effect of culture medium type and culture time on the production of β-exotoxin was also studied. Glucose oxidase has a significant inhibitory effect on the activity of β-exotoxin produced by strain E-013. Preliminary purification of β-exotoxin was obtained by ethanol fractionation, barium salt precipitation and ion exchange chromatography. The UV absorption spectrum has the typical characteristics of adenine nucleotides: the maximum absorption wavelength (λ max) is 258 nm and the minimum absorption wavelength (λ min) is 233 nm.