Alfred Koch has given considerable attention to the subject of nitrogen fixation by bacteria as resulting from their symbiosis with alga~. Many others have also investigated various features of this problem. In spite of all this there are numerous questions which remain unsolved. The use of soil cultures for such studies is objectionable on account of the soil's complexity, its variety of flora...

background and objectives: azotobacter is a diazotroph bacterium reported to possess various plant growth-promoting characteristics.the aim of this study was to isolate azotobacter strains capable of fixing nitrogen and effectively hydrolyzing both organic and inorganic pi compounds. materials and methods: in this study, soil samples collected from a diverse range of slightly alkaline soil type...

In order to study of the effect of seed inoculation with PGPR on nitrogen and phosphorus use efficiency of spring wheat in different levels of nitrogen and phosphorus fertilizers, an experimental was conducted at the Research Farm of Mohageh Ardabili University, Ardabil, Iran during 2012 year. The combination of nitrogen fertilizer in three levels (0, 40 and 80 kg N/ha as urea) and phosphorus f...

in order to study of the effect of seed inoculation with pgpr on nitrogen and phosphorus use efficiency of spring wheat in different levels of nitrogen and phosphorus fertilizers, an experimental was conducted at the research farm of mohageh ardabili university, ardabil, iran during 2012 year. the combination of nitrogen fertilizer in three levels (0, 40 and 80 kg n/ha as urea) and phosphorus f...

An Azotobacter vinelandii homolog to the Salmonella typhimurium mutS gene was discovered upstream of the fdxA gene. The product of this gene is much more similar to S. typhimurium MutS than either is to the HexA protein of Streptococcus pneumoniae. An A. vinelandii delta mutS mutant strain was shown to have a spontaneous mutation frequency 65-fold greater than that of the wild type.

Azotobacter vinelandii cells can be transformed at high frequencies with the broad-host-range plasmids pRK2501, RSF1010, and pGSS15, using a modification of the procedure developed by Page and von Tigerstrom (J. Bacteriol. 139:1058-1061, 1979) for chromosomal DNA-mediated transformation. The frequency of transformation per microgram of plasmid DNA per viable cell with pRK2501 and pGSS15 was abo...

Genes that seem to be involved in the initial steps of infection of a legume by Rhizobium have been transferred, by transformation, to mutant strains of Azotobacter vinelandii that are unable to fix nitrogen. These genes code for a surface antigen that binds specifically to a protein from the host plant.