title: New method of denitrification analysis of bradyrhizobium field isolates by gas chromatographic determination of (15)N-labeled N(2).
abstract: To evaluate the denitrification abilities of many Bradyrhizobium field isolates, we developed a new (15)N-labeled N(2) detection methodology, which is free from interference from atmospheric N(2) contamination. (30)N(2) ((15)N(15)N) and (29)N(2) ((15)N(14)N) were detected as an apparent peak by a gas chromatograph equipped with a thermal conductivity detector with N(2) gas having natural abundance of (15)N (0.366 atom%) as a carrier gas. The detection limit was 0.04% (30)N(2), and the linearity extended at least to 40% (30)N(2). When Bradyrhizobium japonicum USDA110 was grown in cultures anaerobically with (15)NO(3)(-), denitrification product ((30)N(2)) was detected stoichiometrically. A total of 65 isolates of soybean bradyrhizobia from two field sites in Japan were assayed by this method. The denitrification abilities were partly correlated with filed sites, Bradyrhizobium species, and the hup genotype.
authors.affiliation: Graduate School of Life Sciences, Tohoku University, Katahira, Aoba-ku, Sendai 980-8577, Japan.
authors.forename: Reiko
authors.initials: R
authors.lastname: Sameshima-Saito
authors.forename: Kaori
authors.initials: K
authors.lastname: Chiba
authors.forename: Kiwamu
authors.initials: K
authors.lastname: Minamisawa
mesh_terms: D000114:Acetylene / Q000494:pharmacology; D020369:Bradyrhizobium / Q000254:growth & development / Q000302:isolation & purification / Q000378:metabolism*; D002849:Chromatography, Gas / Q000379:methods; D003470:Culture Media; D009566:Nitrates / Q000378:metabolism; D009573:Nitrites / Q000378:metabolism*; D009587:Nitrogen Isotopes / Q000378:metabolism*; D009609:Nitrous Oxide / Q000378:metabolism*; D013025:Glycine max / Q000382:microbiology
chemical_list: D003470:Culture Media; D009566:Nitrates; D009573:Nitrites; D009587:Nitrogen Isotopes; D009609:Nitrous Oxide; D000114:Acetylene