抄録
An improved method for transformation of derivative strains of A. aceti subsp. aceti No. 1023 with plasmid DNA has been developed. Addition of polyethylene glycol or dimethylsulfoxide increased the transformation efficiency by a factor of about ten. In the presence of PEG 4, 000, various transformation conditions were examined. Cells were also made transformation competent by treatment with other divalent cations than Ca2+. The pH of the buffer did not affect the efficiency significantly. The growth phase influenced the efficiency. Mutants showing high competence were derived by treatment with N-methyl-N'-nitro-N-nitrosoguanidine. By the improved method using the highly transformable mutants, a transformation efficiency of approximately 105 transformants per μg plasmid DNA was achieved.
