Maia M, Sanchez J M, Vela G R
Department of Biological Sciences, North Texas State University, Denton 76203.
J Bacteriol. 1988 Apr;170(4):1984-5. doi: 10.1128/jb.170.4.1984-1985.1988.
Four laboratory strains and two isolates of Azotobacter vinelandii were found to contain plasmids. Twenty-five laboratory strains which could fix nitrogen did not have free, covalently closed circular plasmid DNA. The plasmids varied in size from 9 to 52 megadaltons, and each strain yielded only one plasmid. No discernible differences in ability to fix nitrogen were found between plasmid-bearing and cured cultures.