摘要
固氮螺菌(Azospirillum)是一类仅在限铵和微好氧条件下固氮的微生物,它可与许多禾本科作物联合共生,具有较大的应用潜力。铵作为固氮作用的调节信号,在固氮螺菌的实际应用中是首要的限制因素。在固氮螺菌中,铵不但具有与肺炎克氏杆菌(Klebsiella pneumoniae)相似的阻遏固氮酶合成的作用,而且还对已合成的固氮酶进行活性调节。
Plasmid pCK3, which carried a constitutive nifA gene of Klebsiella pneumoni-ae, was transferred into a dra T- mutant strain of Azospirillum brasilense. It was found that pCK3 could not derepress nif gene expression of A. brasilense under high concentration of ammonia. Combined with the result of the phenotypes of the kanamysin resistant gene from pCK3 in A. brasilense under different incubated conditions, it demonstrated that NifA activity was inhibited by ammonia. We suppose that there is a negative regulator in A. brasilense, although not existing in K. pneumoniae, wihich has effect on NifA activity by ammonia.
出处
《生物工程学报》
CAS
CSCD
北大核心
1995年第4期385-388,共4页
Chinese Journal of Biotechnology
基金
863计划资助项目