Koyama Y, Hoshino T, Tomizuka N, Furukawa K
J Bacteriol. 1986 Apr;166(1):338-40. doi: 10.1128/jb.166.1.338-340.1986.
Genetic transformation of auxotrophs of the extreme thermophile Thermus thermophilus HB27 to prototrophy was obtained at high frequencies of 10(-2) to 10(-1) when proliferating cell populations were exposed to chromosomal DNA from a nutritionally independent wild-type strain. The transformation frequency was proportional to the DNA concentration from 10 pg/ml to 100 ng/ml. T. thermophilus HB27 cells did not require chemical treatment to induce competence, although optimal transformation was obtained by the addition of a divalent cation (Ca2+ or Mg2+). Competence was maintained throughout the growth phase, with the highest transformation frequencies at pH 6 to 9 and at 70 degrees C. T. thermophilus HB27 and four other typical Thermus strains, T. thermophilus HB8, T. flavus AT62, T. caldophilus GK24, and T. aquaticus YT1, were also transformed to streptomycin resistance by DNA from their own spontaneous streptomycin-resistant mutants. A cryptic plasmid, pTT8, from T. thermophilus HB8 was introduced into T. thermophilus HB27 Pro- at a frequency of 10(-2).
当增殖细胞群体暴露于来自营养独立野生型菌株的染色体DNA时，嗜热栖热菌HB27的营养缺陷型向原养型的遗传转化以10⁻²至10⁻¹的高频获得。转化频率与10 pg/ml至100 ng/ml的DNA浓度成正比。嗜热栖热菌HB27细胞不需要化学处理来诱导感受态，尽管通过添加二价阳离子（Ca²⁺或Mg²⁺）可获得最佳转化效果。在整个生长阶段都保持感受态，在pH 6至9和70℃时转化频率最高。嗜热栖热菌HB27和其他四种典型的栖热菌菌株，嗜热栖热菌HB8、黄栖热菌AT62、嗜热栖热菌GK24和嗜热水栖热菌YT1，也被来自它们自身自发链霉素抗性突变体的DNA转化为链霉素抗性。来自嗜热栖热菌HB8的隐蔽质粒pTT8以10⁻²的频率导入嗜热栖热菌HB27 Pro⁻。
