Ca2+和 Sr2+诱导大肠埃希菌感受态细胞的形成及转化的影响

摘要

In order to study the formation mechanism of competence cells under the induction of metal ions and reveal the transformation mechanism,Ca2 + and Sr2 +(0 ~ 140 mmol/ L)were respectively used in this study to prepare E. coli competence cells and transform them. The results showed that the valence of competence cells induced by different concentration of Ca2 + ;Sr2 + ions was different and the two metal ions all had fairly large effects on E. coli cell internal and external membrane permeability,however,no direct relation to the degree of variation and transformation rate of the cell internal and external membrane. The results of EM observation showed that the untreated cells were adhered with each other into cluster;but the competence cells were disperse in total,adhered partly;the existence of cells af-ter transformation were independent with clear edges.%为研究金属离子诱导下感受态细胞形成的机理及揭示转化发生的机制，分别用 Ca2+和 Sr2+（0~140 mmol/ L）制备大肠埃希菌感受态细胞并转化。研究结果表明，不同浓度的 Ca2+和 Sr2+诱导的感受态细胞的效价不同，两种金属离子对大肠埃希菌细胞内外膜的通透性均有较大影响，但细胞内外膜的改变程度与转化率无直接关系；电镜结果显示，未处理的细胞呈簇聚集发生粘连现象，感受态细胞整体呈分散状态，局部发生聚集，而转化后的细胞独立存在，边缘异常清晰。