The production and utilization of nitric oxide by a new, denitrifying strain of Pseudomonas aeruginosa.
When a new strain of Pseudomonas aeruginosa was grown aerobically and then transferred to anaerobic conditions, cells reduced NO3- quantitatively to NO2- in NO3(-)-respiration. In the absence of nitrate, NO2- was immediately reduced to NO or N2O but not to N2 indicating that NO2(-)-reductase but not N2O-reductase was active. The formation of the products NO or N2O depended on the pH in the medium and the concentration of NO2- present. When P. aeruginosa was grown anaerobically for at least three days N2O-reductase was also active. Such cells reduced NO to N2 via N2O. The new strain generated at H(+)-gradient and grew by reducing N2O to N2 but not by converting NO to N2O. For comparison, Azospirillum brasilense Sp7 showed the same pattern of NO-reduction. In contrast, Paracoccus denitrificans formed 3.5 H+/NO during the reduction of NO to N2O in oxidant pulse experiments but could not grow in the presence of NO. Thus the NO-reduction pattern in P. denitrificans on one side and P. aeruginosa and A. brasilense on the other was very different. The mechanistic implications of such differences are discussed.
Vosswinkel
R
R
Botanisches Institut, Universität zu Köln, Federal Republic of Germany.
Neidt
I
I
Bothe
H
H
D000693:Anaerobiosis; D015806:Azospirillum brasilense / Q000378:metabolism; D003470:Culture Media; D006863:Hydrogen-Ion Concentration; D009569:Nitric Oxide / Q000378:metabolism*; D009609:Nitrous Oxide / Q000378:metabolism; D010084:Oxidation-Reduction; D010231:Paracoccus denitrificans / Q000378:metabolism; D011550:Pseudomonas aeruginosa / Q000378:metabolism*; D012988:Soil Microbiology
D003470:Culture Media; D009569:Nitric Oxide; D009609:Nitrous Oxide