title: Effect of N oxyanions on anaerobic induction of nitrate reductase in subcellular fractions of Bradyrhizobium sp. (Lupinus).
abstract: Anaerobic induction of nitrate reductase in subcellular fractions of Bradyrhizobium sp. strain USDA 3045 showed fivefold increase of the enzyme activity in spheroplasts, considered as the source of intact-membrane-bound nitrate reductase, within a 3 h time frame after nitrate addition. Such a dynamics was confirmed at the protein level, with antibodies specific to membrane-bound nitrate reductase. Nitrate reductase activity in the periplasm was one order of magnitude lower and significant only at initial 3 h of induction, within a narrow range of nitrate added. Nitrite induced the membrane-bound nitrate reductase at least 70% as effectively as nitrate, as judged from its activity pattern and Western blot analysis. The limited ability of Bradyrhizobium sp. to dissimilate > or =5 mM nitrate is not due to direct inhibition of respiratory nitrate reductase by accumulated nitrite. Moreover, a synergistic induction of membrane-bound nitrate reductase by nitrate and nitrite was indicated due to a twofold higher protein synthesis after simultaneous addition of these N oxyanions than when they were given separately.
authors.affiliation: Institute of Experimental Biology, A. Mickiewicz University, Umultowska 89, 61-614 Poznan, Poland. polcyn@rose.man.poznan.pl
authors.forename: Władysław
authors.initials: W
authors.lastname: Polcyn
authors.forename: Robert
authors.initials: R
authors.lastname: Luciński
mesh_terms: D000693:Anaerobiosis; D000838:Anions / Q000378:metabolism*; D001426:Bacterial Proteins / Q000032:analysis; D020369:Bradyrhizobium / Q000737:chemistry / Q000201:enzymology*; D004790:Enzyme Induction; D031297:Lupinus / Q000382:microbiology; D050901:Nitrate Reductase / Q000378:metabolism*; D009566:Nitrates / Q000378:metabolism*; D009573:Nitrites / Q000378:metabolism; D013347:Subcellular Fractions / Q000378:metabolism*; D013997:Time Factors
chemical_list: D000838:Anions; D001426:Bacterial Proteins; D009566:Nitrates; D009573:Nitrites; D050901:Nitrate Reductase