枯草芽胞杆菌紫外线诱变实验方案的优化

Optimized protocol for ultraviolet mutagenesis of Bacillus subtilis

摘要:

【目的】优化枯草芽胞杆菌紫外线诱变实验教学方案，以便学生在实验中获得预期结果。【方法】从菌体培养、活菌浓度估测和辐射参数三方面探讨影响实验结果的因素。【结果】采用液体培养法活化菌体有利于制备均匀的菌悬液，采用比浊法估测初始菌悬液浓度可以指导学生将其稀释至102?103 cfu/mL的浓度；涂布接种后平板表面干燥、培养皿盖内无明显水珠附着，是获得单菌落的关键；在紫外辐射过程中采用固定的菌悬液体积和搅拌速度，可以获得规律性的辐射剂量——致死效应曲线。【结论】优化后的方案实验结果易得、重复性好，可供教学和研究实验参考。

Abstract:

[Objective] To optimize the experiment protocol of ultraviolet (UV) radiation of Bacillus subtilis so that students can get better results in the experiment lesson. [Methods] We optimized the protocol by determining the best bacterial cultivation, estimation of viable cells, and UV-radiation parameters. [Results] Liquid medium was better than agar slant to obtain a homogeneous suspension of cells. The cell amount of the initial bacterial suspension was estimated efficiently by turbidimetric method, which was convenient to dilute the initial suspension to a concentration of 102?103 CFU/mL. Dry surface covered with dry dish was necessary for the formation of singlet colonies on a bacteria-inoculated plate. During UV exposure, the lethal effect was affected by the adding volume of suspension and mixing speed. [Conclusion] The optimized protocol produces repeatable results easily and can be used for teaching or research.