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    The accumulation and histological effects of organometallic fungicides Propineb and Maneb in the kidneys of fetus and female rats during pregnancy
    (Elsevier Ireland Ltd, 1998) Guven, K; Deveci, E; Akba, O; Onen, A; de Pomerai, D
    Dithiocarbamate propineb and maneb are organometal fungicides, which are widely used for the control of diseases in plants. Female Wistar rats were exposed orally to 200 and 400 ppm propineb and 250 ppm maneb, from the sixth day of gestation up to birth. We found that the body weights of both one-day old litters and their fungicide-treated mothers were lower than those of controls. Histological examination of the kidneys of fetus and fungicide-treated pregnant females showed a variety of histopathological effects. Moreover, the analysis of zinc (Zn) and manganese (Mn) concentrations (using inductively coupled plasma-atomic emission spectrometry) in the kidneys of pregnant females exposed to organometallic fungicides during pregnancy demonstrated that the metal concentrations in the kidney were higher than those of controls. However, the renal metal concentrations were significantly increased in the litters subjected to the fungicides during gestation, indicating that high levels of the trace metals in the organ of fetus may well be due to the fungicides easily passing the placental barrier. (C) 1998 Elsevier Science Ireland Ltd. All rights reserved.
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    A comparative study of bioassays based on enzyme biosynthesis in Escherichia coli and Bacillus subtilis exposed to heavy metals and organic pesticides
    (Elsevier Science Inc, 2003) Guven, K; Togrul, S; Uyar, F; Ozant, S; De Pomerai, DI
    Two enzyme assays, namely beta-galactosidase in Escherichia coli (E.C.3.2.1.23) and alpha-amylase in Bacillus subtilis (E.C.3.2.1.1), were compared following exposure to various concentrations of heavy metals and organic pesticides. It was shown that alpha-amylase biosynthesis in the Gram-positive bacteria was more sensitive to heavy metals, particularly to mercury as low as 0.1 ppm, compared to beta-galactosidase in the Gram-negative bacteria. The results of organic pesticide treatment were more clear-cm when comparing both assays. Alpha-amylase test system can detect the inhibition by the organometallic fungicides Maneb and Mancozeb at as low as 0.1 ppm, while no inhibition with beta-galactosidase system up to as high as 100 ppm. The effect of organic insecticide endosulfan on alpha-amylase was also seen at very low concentrations (0.048 ppm). The electrophoretic analysis also revealed the inhibition of enzyme biosynthesis at the tested toxicant concentrations. (C) 2003 Elsevier Science Inc. All rights reserved.
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    The effects of ionic and non-ionic detergents on Escherichia coli ?-Galactosidase activity.
    (Mbr Press Inc, 1998) Guven, K; Bashan, M
    The effects of several ionic and non-ionic detergents on P-Galactosidase activity at 30 degrees C have been evaluated. The detergent concentrations tested were in the ranges that are already used in most assays to permeablise and reveal proteins from most tissues. The results obtained indicate that the anionic detergent SDS at all concentrations inhibited beta-Galactosidase activity, whereas non-ionic detergents, Triton-X 100 and Tween 20 have no effects on the enzyme activity. The electrophoretic analysis of SDS-exposed enzyme shows two bands corresponding to 170 kD and 116 kD, only the former being active.
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    The effects of organic pesticides on inner membrane permeability in Escherichia coli ML35
    (Springer, 2005) Guven, K; Yolcu, M; Gul-Guven, R; Erdogan, S; De Pomerai, D
    We have tested whether some pesticides might cause inner membrane leakage in ML35 Escherichia coli cells, which express beta-galactosidase (lacZ; EC 3.2.1.23) constitutively but lack the permease (lacY) required for substrate entry. The activity of beta-galactosidase (indicative of substrate leakage through the inner membrane) was increased by various concentrations of pesticides, including the organometallic fungicides maneb and mancozeb, the insecticide Thiodan, and the herbicide Ally, as well as by antibiotics such as ampicillin, gramicidin D, and the calcium ionophore A23187. The enzyme activity was increased by up to similar to 30% when the E. coli ML35 strain was exposed to various concentrations (between 50 and 250 ppm) of both fungicides. Thiodan had only a slight effect on beta-galactosidase activity (increase of 12.8%), whereas, among the antibiotics, the calcium ionophore at 20 mu g/ml caused a significant increase in enzyme activity by up to 61.8%. This effect is similar to that of sodium dodecyl sulfate, used as positive control (similar to 70% increase). Accumulation of maneb and mancozeb by bacterial cells was also studied taking advantage of their metal content and using atomic absorption spectrophotometry. In parallel with the increase in enzyme activity, both fungicides accumulated in the cells as a function of their concentration. Time course experiments (3, 6, and 9 h) of fungicide accumulation and of bacterial growth at various pesticide concentrations were also carried out. Maneb seems to inhibit the bacterial growth better than mancozeb. In addition, maneb uptake increases with time up to 9 h at all tested concentrations, whereas the accumulation of mancozeb is similar at all the exposure times tested. This indicates a different uptake and/or metabolizing strategy by E. coli cells for the two fungicides.