Participation of oxygen in the bacterial transformation of 2,4,6-trinitrotoluene.
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.
Naumenko
E A
EA
Kazan State University, Kazan 420008, Russia.
Naumov
A V
AV
Suvorova
E S
ES
Gerlach
R
R
Ziganshin
A M
AM
Lozhkin
A P
AP
Silkin
N I
NI
Naumova
R P
RP
D000332:Aerobiosis; D001409:Bacillus cereus / Q000378:metabolism*; D010084:Oxidation-Reduction; D010100:Oxygen / Q000378:metabolism; D013481:Superoxides / Q000378:metabolism*; D014303:Trinitrotoluene / Q000737:chemistry* / Q000378:metabolism
D013481:Superoxides; D014303:Trinitrotoluene; D010100:Oxygen