A recombinant plasmid was constructed by transferring Hind Ⅲ DNA fragment of pHP 45 : : omega - Hg , including Hg^(++)-resistant gene , into Hind Ⅲ restriction site of pGA 642 and was named pSA 2. pSA 2 was transfered into E.coli S17-1 and the tra...
A recombinant plasmid was constructed by transferring Hind Ⅲ DNA fragment of pHP 45 : : omega - Hg , including Hg^(++)-resistant gene , into Hind Ⅲ restriction site of pGA 642 and was named pSA 2. pSA 2 was transfered into E.coli S17-1 and the transformant was convinced on selection media.
By the dual mating , the transfer frequency of pGA 642 was increased about 10^3 times than the frequency obtained by the triple mating. The transfer frequency of pGA 642 varied greatly dependent on pH values, and the best transfer frequency was about 2.7 × 10 exp (-3) at pH 5.5. The optical mating time was 36 hrs, and the transfer frequency was 2.9 × 10 exp (-2).