title: Mutational replacement of molybdenum by vanadium in assimilation of N2 or NO3- as nitrogen source in the cyanobacterium Nostoc muscorum.
abstract: Tungsten resistant (Wr) mutants of Het+Nif+Nia+, Het+Nif-Nia+ and Het+Nif+Nia- strains of Nostoc muscorum were isolated with severely defective molybdate transport activity. All such mutants showed vanadium (V)-dependent nitrogenase activity and/or nitrate reductase activity and V-dependent growth on N2-nitrogen and/or NO3(-)-nitrogen and V-dependent NO3(-)-repression of heterocyst formation and nitrogenase activity. None of them grew with molybdenum (Mo) under parallel growth condition. Results strongly suggest the ability of V to replace Mo in N2-assimilation or NO3(-)-assimilation under Mo-deficiency.
authors.affiliation: Department of Biological Sciences, Rani Durgavathi University, Jabalpur, M.P., India.
authors.forename: S
authors.initials: S
authors.lastname: Singh
authors.forename: D
authors.initials: D
authors.lastname: Chakravarty
authors.forename: H N
authors.initials: HN
authors.lastname: Singh
mesh_terms: D001692:Biological Transport; D000458:Cyanobacteria / Q000235:genetics / Q000378:metabolism*; D008982:Molybdenum / Q000378:metabolism*; D009154:Mutation; D050901:Nitrate Reductase; D009565:Nitrate Reductases / Q000378:metabolism; D009566:Nitrates / Q000378:metabolism*; D009584:Nitrogen / Q000378:metabolism*; D009586:Nitrogen Fixation; D009591:Nitrogenase / Q000378:metabolism; D010641:Phenotype; D014639:Vanadium / Q000378:metabolism*
chemical_list: D009566:Nitrates; D014639:Vanadium; D008982:Molybdenum; D009591:Nitrogenase; D009565:Nitrate Reductases; D050901:Nitrate Reductase; D009584:Nitrogen