论文部分内容阅读
This paper describes the role of nifA product on the ammonia regulation of nitrogen fixation in K. pneumoniae. A plasmid carrying nifA gene under the promoter of tetracycline resistance gene was constructed. When this nifA carrying plasmid was introduced into a glnAG mutant, the Nif~-phenotype of this gln mutant was suppressed. Furthermore, when the plasmid was introduced into the wild type and glnAG mutant, derepression of nitrogenase synthesis in ammonia occurred in both strains and the products of nif genes can be detected by two-dimensional gel electrophoresis in the extracts of these ammonia-grown bacterial cells.The constitutive synthesis of nitrogenase in NH_4~+ was also demonstrated in free living nitrogen-fixing bacteria, Enterobacter cloacae, when the bacteria received the plasmid carrying nifA gent from K. pneumoniae.
This paper describes the role of nifA product on the ammonia regulation of nitrogen fixation in K. pneumoniae. A plasmid carrying nifA gene under the promoter of tetracycline resistance gene was constructed. When this nifA carrying plasmid was introduced into a glnAG mutant, the Nif ~ -phenotype of this gln mutant was suppressed. Furthermore, the products of nif genes were detected by two-dimensional gel electrophoresis in the extracts of these ammonia-grown bacterial cells. The constitutive synthesis of nitrogenase in NH 4 - + was also demonstrated in free living nitrogen-fixing bacteria, when the bacteria received the plasmid carrying nifA gent from K. pneumoniae.