title: Participation of oxygen in the bacterial transformation of 2,4,6-trinitrotoluene.
abstract: The exposure of Bacillus cereus ZS18 cell suspensions to 2,4,6-trinitrotoluene (TNT) in the absence of other oxidizable substrates increases oxygen uptake, exceeding the basal level of respiration of the bacterium 1.5- and 2-fold with 50 and 100 mg/liter of TNT, respectively. The interaction of both living and to less extent dead bacterial cells with TNT results in the accumulation of superoxide anion (O2*-) in the extracellular medium, which was revealed by the EPR spectroscopy. The accumulation of O2*- decreased by 50-70% in the presence of Cu,Zn-superoxide dismutase of animal origin. In the presence of living bacterial cells, the level of TNT decreased progressively, yielding hydroxylaminodinitrotoluenes together with O2*-. In the presence of heat-killed cells, a moderate decrease in TNT was observed, and the appearance of O2*- was not accompanied by the production of any detectable TNT metabolites. Chelating agents inhibited the transformation of TNT and decreased the formation of O2*-. The demonstrated generation of O2*- during the interaction of TNT with K4[Fe(CN)6] together with the observed effects of chelating agents suggest the participation of iron in the one-electron reduction of TNT and the functioning of an extracellular redox cycle with the involvement of molecular oxygen.
authors.affiliation: Kazan State University, Kazan 420008, Russia.
authors.forename: E A
authors.initials: EA
authors.lastname: Naumenko
authors.forename: A V
authors.initials: AV
authors.lastname: Naumov
authors.forename: E S
authors.initials: ES
authors.lastname: Suvorova
authors.forename: R
authors.initials: R
authors.lastname: Gerlach
authors.forename: A M
authors.initials: AM
authors.lastname: Ziganshin
authors.forename: A P
authors.initials: AP
authors.lastname: Lozhkin
authors.forename: N I
authors.initials: NI
authors.lastname: Silkin
authors.forename: R P
authors.initials: RP
authors.lastname: Naumova
mesh_terms: D000332:Aerobiosis; D001409:Bacillus cereus / Q000378:metabolism*; D010084:Oxidation-Reduction; D010100:Oxygen / Q000378:metabolism; D013481:Superoxides / Q000378:metabolism*; D014303:Trinitrotoluene / Q000737:chemistry* / Q000378:metabolism
chemical_list: D013481:Superoxides; D014303:Trinitrotoluene; D010100:Oxygen