Pk. Mohapatra et U. Schiewer, EFFECT OF DIMETHOATE AND CHLORFENVINPHOS ON PLASMA-MEMBRANE INTEGRITYOF SYNECHOCYSTIS SP. PCC-6803, Ecotoxicology and environmental safety, 41(3), 1998, pp. 269-274
The organophosphorus (OP) insecticides dimethoate and chlorfenvinphos,
at all selected concentrations (0-500 mu mol liter(-1)), reduced the
rate of accumulation of uranine and enhanced fluorescence quenching of
9-amino-6-chloro-2-methoxyacridine (ACMA), There was a significant no
nlinear negative correlation between insecticide concentrations and ur
anine accumulation. The reduction in amount of uranine trapped inside
the cells was greater in cultures treated with chlorfenvinphos, wherea
s quenching of ACMA fluorescence was found to be greater with dimethoa
te treatment. A marked difference between the effects of dimethoate an
d chlorfenvinphos on permeability changes in the plasma membrane of Sy
nechocystis was also noted. The release of cellular organic carbon was
observed at each concentration of chlorfenvinphos, whereas with dimet
hoate such an effect was noted at greater than or equal to 200 mu mol
liter(-1). The rate of uptake of substrates like 2-deoxyglucose and 2-
aminoisobutyric acid (AIBA) was significantly (negatively) correlated
with concentrations of both the insecticides. Chlorfenvinphos was more
effective than dimethoate in reducing the active uptake of nonmetabol
izable sugar and amino acid analogues, (C) 1998 Academic Press.