title: Mo-independent nitrogenase 3 is advantageous for diazotrophic growth of Azotobacter vinelandii on solid medium containing molybdenum.
abstract: Competition experiments between wild-type Azotobacter vinelandii and a mutant lacking Mo-independent nitrogenase 3 indicate that nitrogenase 3 provides an advantage during diazotrophic growth on agar media containing 100 to 500 nM Na2MoO4 but not in liquid media under the same conditions. Expression of nitrogenase 3 in wild-type cells growing on agar surfaces was verified with an anfH-lacZ fusion and by detection of nitrogenase 3 subunits. These results show that nitrogenase 3 is important for diazotrophic growth on agar medium at molybdenum concentrations that are not limiting for Mo-dependent diazotrophic growth in liquid medium.
authors.affiliation: U.S. Department of Agriculture, Agriculture Research Service, Raleigh, North Carolina.
authors.forename: R H
authors.initials: RH
authors.lastname: Maynard
authors.forename: R
authors.initials: R
authors.lastname: Premakumar
authors.forename: P E
authors.initials: PE
authors.lastname: Bishop
mesh_terms: D016948:Azotobacter vinelandii / Q000187:drug effects / Q000201:enzymology* / Q000254:growth & development*; D003470:Culture Media; D015870:Gene Expression / Q000187:drug effects; D005798:Genes, Bacterial; D007527:Isoenzymes / Q000096:biosynthesis / Q000378:metabolism; D008982:Molybdenum / Q000494:pharmacology*; D009591:Nitrogenase / Q000096:biosynthesis / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis; D001616:beta-Galactosidase / Q000096:biosynthesis
chemical_list: D003470:Culture Media; D007527:Isoenzymes; D011993:Recombinant Fusion Proteins; D008982:Molybdenum; C024687:sodium molybdate(VI); D009591:Nitrogenase; D001616:beta-Galactosidase