几株Bt菌株对紫外线的抗性研究

Discussion on the Resistances of Several Bt Strains to UV Radiation

[目的]寻求高抗紫外线的Bt菌株。[方法]采用不同照射时间的紫外线(UV)对1株野生型Bt菌株及3株Bt菌株Bt001、Bt200、Bt087进行照射处理后再置于32℃培养箱中培养16h。[结果]Bt野生菌株在UV处理3min后已基本全部失活,而Bt001、Bt200、Bt087在UV处理8min后仍有活性。菌株Bt001、Bt200、Bt087对UV的抗性均强于野生Bt菌株,其中,Bt200相对弱些,UV处理9min后已无菌落;Bt087最弱,UV处理8min后已无菌落;而菌株Bt001对UV的抗性最强,UV处理13min后仍有菌落出现,说明不同的Bt菌株,其遗传背景是不同的。另外,Bt001经紫外线照射9min培养16h后发现有9个菌落发生明显的变异,菌落呈棕黄色,菌落明显比原始菌落小,油镜下观察涂片,其菌体比原始菌体小,说明Bt001为明显发生突变的菌株。[结论]菌株Bt001对UV的抗性最强。

[Objective] The purpose was to seek for Bt strains with high resistance to UV radiation. [Method] A wild Bt strain and 3 Bt strains of BtO01, Bt200, Bt087 were radiated by UV radiation for different time, and then cultured in incubator at 32 ℃ for 16 h. [Result] Almost all the wild Bt strains lost their activities after they were treated by UV radiation for 3 min, but Bt001, Bt200 and Bt087 also had activities after they were treated by UV radiation for 8 min. The resistances of strains Bt001, Bt200 and Bt087 to UV radiation were stronger than that of the wild Bt strain, among which, Bt200 was relatively weaker, there was no colony after it was treated by UV radiation for 9 min; Bt087 was weakest, there was no colony after it was treated by UV radiation for 8 rain; the resistance of the strain Bt001 to UV radiation was strongest, there was also colony appeared after it was treated by UV radiation for 13 rain, indicating that the genetic backgrounds of different Bt strains were different. Besides, after Bt001 was treated by UV radiation for 9 rain and then cultured for 16 h, there were 9 colonies of Bt001 found to have significant variations and they were brown yellow and significantly smaller than their initial colonies. It was found that their cells were smaller than their initial cells through observing their smears under oil microscope, indicating that Bt001 was the strain with significant variation. [Conclusion] The resistance of the strain Bt001 to UV radiation was strongest.