Effects of Pesticides on Nitrite Oxidation by Nitrobacter agilis1
AUTOR(ES)
Winely, C. L.
RESUMO
The influence of pesticides on the growth of Nitrobacter agilis in aerated cultures and on the respiration of N. agilis cell suspensions and cell-free extracts was studied. Two pesticides, aldrin and simazine, were not inhibitory to growth of Nitrobacter, but five compounds [isopropyl N-(3-chlorophenyl) carbamate (CIPC), chlordane, 1,1-dichloro-2,2-bis (p-chlorophenyl) ethane (DDD), heptachlor, and lindane] prevented growth when added to the medium at a concentration of 10 μg/ml. Whereas CIPC and eptam prevented nitrite oxidation by cell suspensions, the addition of DDD and lindane resulted in only partial inhibition of the oxidation. Heptachlor and chlordane also caused only partial inhibition of oxidation, but were more toxic with cell-free extract nitrite oxidase. None of the pesticides inhibited the nitrate reductase activity of cell-free extracts, but most caused some repression of cytochrome c oxidase activity. Heptachlor was the most deleterious compound.
