Authors: Singh Rama K Stevens S Edward Bryant Donald A
Publish Date: 1987/12/01
Volume: 48, Issue: 1-2, Pages: 53-58
Abstract
Rama K Singh S Edward Stevens Donald A Bryant Molecular cloning and physical mapping of the nitrogenase structural genes from the filamentous nonheterocystous cyanobacterium Pseudanabaena sp PCC7409 FEMS Microbiology Letters Volume 48 Issue 12 December 1987 Pages 53–58 https//doiorg/101111/j157469681987tb02514xSequences homologous to the structural genes for dinitrogenase nifD and nifK and nitrogenase reductase nifH have been cloned from the filamentous nonheterocystous cyanobacterium Pseudanabaena PCC7409 The nifHDK− homologous sequences were shown to reside on a 65kb EcoRI restriction fragment by using a restriction fragment encoding the Klebsiella pneumoniae nifHDK genes as a heterologous hybridization probe This 65kb restriction fragment was cloned from a λ gtwes EcoRI library of the Paseudanabaena sp PCC7409 genome This fragment was subcloned into the plasmid vector pUC9 to generate plasmid pPSU20 A detailed physical map of the insert in plasmid pPSU20 was determined and relative positions of the nifH nifD and nifK homologous sequences on this fragment were determined by hybridization analysis with genespecific fragments derived from the corresponding Anabaena sp PCC7120 genes The results indicate that these genes are contiguous in Pseudanabaena sp PCC 7409 and are arranged in the order nifH nifD and nifK This arrangement resembles that observed for other nonheterocystous cyanobacteria but differs from that observed for Anabaena Calothrix and Nostoc species
Keywords: