Biomaterial Database

Transformation of Azotobacter vinelandii strains unable to fix nitrogen with Rhizobium spp. DNA. 1978

W J Page

The phenotypes of Azotobacter vinelandii ATCC 12837 strains defective in nitrogen fixation (Nif-) were characterized by intrageneric transformation with known Nif- strains of A. vinelandii OP. These former mutant strains were used as recipients for intergeneric transformation by deoxyribonucleic acid (DNA) prepared from Rhizobium spp. to determine if the rhizobia would transform the Azotobacter Nif- phenotypes to Nif+. The frequency of Nif+ transformants using Rhizobium DNA was always less than the frequency using Azotobacter wild-type DNA but was greater than the spontaneous reversion frequency. The Azotobacter Nif+ recombinants also were stable. DNA from all of the Rhizobium spp. transformed to Nif+ Azotobacter mutants defective in the nitrogenase component I (molybdoferredoxin); however, some recombinants had a lower nitrogenase activity and a delayed nitrogenase depression time. Mutants defective in the pleiotrophic transcriptional control of both nitrogenase components were transformed to Nif+ by the asymbiotic nitrogen fixing Rhizobium sp. 32H1 and 41A1, but not the symbiotic nitrogen-fixing species. The significance of these results and the possible future applications of this system are discussed.

UI	MeSH Term	Description	Entries
D009586	Nitrogen Fixation	The process in certain BACTERIA; FUNGI; and CYANOBACTERIA converting free atmospheric NITROGEN to biologically usable forms of nitrogen, such as AMMONIA; NITRATES; and amino compounds.	Diazotrophy,Diazotrophic Activity,Dinitrogen Fixation,N2 Fixation,Activities, Diazotrophic,Activity, Diazotrophic,Diazotrophic Activities,Fixation, Dinitrogen,Fixation, N2,Fixation, Nitrogen
D009591	Nitrogenase	An enzyme system that catalyzes the fixing of nitrogen in soil bacteria and blue-green algae (CYANOBACTERIA). EC 1.18.6.1.	Dinitrogenase,Vanadium Nitrogenase,Nitrogenase, Vanadium
D010641	Phenotype	The outward appearance of the individual. It is the product of interactions between genes, and between the GENOTYPE and the environment.	Phenotypes
D011995	Recombination, Genetic	Production of new arrangements of DNA by various mechanisms such as assortment and segregation, CROSSING OVER; GENE CONVERSION; GENETIC TRANSFORMATION; GENETIC CONJUGATION; GENETIC TRANSDUCTION; or mixed infection of viruses.	Genetic Recombination,Recombination,Genetic Recombinations,Recombinations,Recombinations, Genetic
D004269	DNA, Bacterial	Deoxyribonucleic acid that makes up the genetic material of bacteria.	Bacterial DNA
D004794	Enzyme Repression	The interference in synthesis of an enzyme due to the elevated level of an effector substance, usually a metabolite, whose presence would cause depression of the gene responsible for enzyme synthesis.	Repression, Enzyme
D001395	Azotobacter	A genus of gram-negative, aerobic bacteria found in soil and water. Its organisms occur singly, in pairs or irregular clumps, and sometimes in chains of varying lengths.
D012231	Rhizobium	A genus of gram-negative, aerobic, rod-shaped bacteria that activate PLANT ROOT NODULATION in leguminous plants. Members of this genus are nitrogen-fixing and common soil inhabitants.
D014169	Transformation, Bacterial	The heritable modification of the properties of a competent bacterium by naked DNA from another source. The uptake of naked DNA is a naturally occuring phenomenon in some bacteria. It is often used as a GENE TRANSFER TECHNIQUE.	Bacterial Transformation