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Plasmids of Azotobacter vinelandii
M Maia1, J M Sanchez, G R Vela
1Department of Biological Sciences, North Texas State University, Denton 76203.
Journal of Bacteriology
|April 1, 1988
Summary
Plasmids were detected in some Azotobacter vinelandii strains, but their presence or absence did not affect nitrogen fixation capabilities. Further research is needed to understand the role of these plasmids in bacteria.
Area of Science:
- Microbiology
- Molecular Biology
- Bacteriology
Background:
- Azotobacter vinelandii is a bacterium known for its nitrogen-fixing abilities.
- Plasmids, which are extrachromosomal DNA molecules, can influence bacterial traits.
- The role of plasmids in the nitrogen fixation of A. vinelandii has not been fully elucidated.
Purpose of the Study:
- To investigate the presence and characteristics of plasmids in Azotobacter vinelandii strains.
- To determine if plasmids influence the nitrogen-fixing capability of A. vinelandii.
Main Methods:
- Plasmid DNA was extracted and analyzed from various laboratory strains and isolates of Azotobacter vinelandii.
- Nitrogen fixation ability was assessed in both plasmid-bearing and plasmid-cured bacterial cultures.
Main Results:
- Plasmids were identified in six of the tested Azotobacter vinelandii strains, varying in size from 9 to 52 megadaltons.
- Twenty-five nitrogen-fixing strains of A. vinelandii lacked detectable free, covalently closed circular plasmid DNA.
- No significant differences in nitrogen fixation ability were observed between strains with and without plasmids.
Conclusions:
- The presence of plasmids in Azotobacter vinelandii does not appear to be essential for nitrogen fixation.
- The function of the identified plasmids in A. vinelandii remains undetermined.
- Further studies are warranted to explore the potential roles of these plasmids in bacterial physiology or adaptation.
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