通过DNA释放及感受态建立进行的枯草杆菌细胞间自然转化

Bacillus subtilis Undergo Cell-to-Cell Natural Transformation via DNA Releasing and Competence Acquiring

以平板转化法研究了枯草杆菌在液体基本培养基 (MM)及LB中培养时通过DNA释放和感受态建立进行的细胞间自然转化 .结果表明 ,该菌在这两种培养基中培养时均可在对数生长期向培养液中主动分泌有生物活性的DNA ,且细胞间接触有利于转化过程的进行 ,暗示在本实验条件下DNA供体细胞可能具有某种主动功能 .对感受态建立的研究表明 ,不仅是MM培养物 ,而且通常被认为不能形成自然感受态的LB培养物 ,当涂布于MM选择平板后均可利用细胞分泌或提取的DNA进行自然转化 ,其转化高峰均出现在对数生长末期 ,转化频率分别可达到 3× 10 -3 和 1.9× 10 -6.

By employing the plate transformation method, the study on Bacillus subtilis cell-to-cell natural genetic transformation was carried out The results showed that the bacteria cultured in the both LB and MM media could actively excrete transforming DNA at exponential growth stage. The cell to cell contact could facilitate the transformation. It was found that the B. subtilis strain, cultured not only in MM medium, but also in LB medium, could be transformed by cell released or chemically extracted DNA by the method of agar plate transformation, although the LB medium was previously believed not to support this process in traditional transformation protocol. Both of the transformation frequency of B. subtilis MM and LB culture peaks appeared at post exponential growth stage and reached at 3×10 -3 and 1.9×10 -6, respectively.