The large plasmids of strain 7653R were digested with restriction enzyme EcoRI. Their DNA fragments were cloned into the expression vector pMP220 to construct a lacZ fusion pool, which were transferred into the recipi...The large plasmids of strain 7653R were digested with restriction enzyme EcoRI. Their DNA fragments were cloned into the expression vector pMP220 to construct a lacZ fusion pool, which were transferred into the recipient strain 7653R Tri-transconjugants were selected onto plates containing X-gal and seed extract Five blue colonies were assayed of their β-galactosidase activity after incubation with or without seed extract. A positive induced strain HN18 was obtained. Hybridization of nodDABC probe on the recombinant plasmid pHN18 showed a 1.7kb positive band.The evidence makes a deduction that the pHN18 containes a promoter of nod operon.展开更多
文摘The large plasmids of strain 7653R were digested with restriction enzyme EcoRI. Their DNA fragments were cloned into the expression vector pMP220 to construct a lacZ fusion pool, which were transferred into the recipient strain 7653R Tri-transconjugants were selected onto plates containing X-gal and seed extract Five blue colonies were assayed of their β-galactosidase activity after incubation with or without seed extract. A positive induced strain HN18 was obtained. Hybridization of nodDABC probe on the recombinant plasmid pHN18 showed a 1.7kb positive band.The evidence makes a deduction that the pHN18 containes a promoter of nod operon.
