【摘要】 用SDS-PAGE电泳分析和生物测定等方法研究了紫外线对苏云金芽孢杆菌(Bacillus thuringiensis,简称Bt)伴孢晶体的损伤及腐植酸对Bt伴孢晶体的保护作用。结果表明,紫外线对Bt伴孢晶体有明显的损伤,伴孢晶体经紫外线辐射3h后溶解性能及生物活性基本丧失。腐植酸对紫外线有较强的吸收作用,能有效地减轻紫外线对Bt伴孢晶体的损伤。更多还原

【Abstract】 The ultraviolet-mediated impairment and inactivation of purified HD-1 parasporal crystals were studied by the means of SDS-PAGE and bioassay. HD-1 parasporal crystals which were irradiated by ultraviolet light for less than 3h lost the normal ability of dissolution in aqueous base and in proteases from the midgut of Helicaverpa armigera ( Hubner) , and lost the original insecticidal activity against H. armigera. Humic acids, soluble natural substances, characterized by the strong absorption of the light of the 200 - 400nm range, and acted as the protectants of parasporal crystals, were very effective on retarding the impairment and inactivation of Bt crystals by ultraviolet. HD-1 crystals with 0.1% humic acids as ultraviolet absorbers exhibited the good solubility in aqueous base and proteases and retained 79.7% of their original insecticide activity after irradiated by ultraviolet light for 6h.更多还原