Soheir M. Amer

Genotoxic effect of 2,4-dichlorophenoxy acetic acid and its metabolite 2,4-dichlorophenol in mouse.

The cytogenetic effect of 2,4-dichlorophenoxy acetic acid (2,4-D) and its metabolite 2,4-dichlorophenol (2,4-DCP) was studied in bone-marrow, germ cells and sperm head abnormalities in the treated mice. Swiss mice were treated orally by gavage with 2,4-D at 1.7, 3.3 and 33 mg kg(-1)BW (1/200, 1/100 and 1/10 of LD(50)). 2,4-DCP was intraperitoneally (i.p.) injected at 36, 72 and 180 mg kg(-1)BW (1/10, 1/5, 1/2 of LD(50)). A significant increase in the percentage of chromosome aberrations in bone-marrow and spermatocyte cells was observed after oral administration of 2,4-D at 3.3 mg kg(-1)BW for three and five consecutive days. This percentage increased and reached 10.8+/-0.87 (P<0.01) in bone-marrow and 9.8+/-0.45 (P<0.01) in spermatocyte cells after oral administration of 2,4-D at 33 mg kg(-1)BW for 24 h. This percentage was, however, lower than that induced in bone-marrow and spermatocyte cells by mitomycin C (positive control). 2,4-D induced a dose-dependent increase in the percentage of sperm head abnormalities. The genotoxic effect of 2,4-DCP is weaker than that of 2,4-D, as indicated by the lower percentage of the induced chromosome aberrations (in bone-marrow and spermatocyte cells) and sperm head abnormalities. Only the highest tested concentration of 2,4-DCP (180 mg kg(-1)BW, 1/2 LD(50)) induced a significant percentage of chromosome aberrations and sperm head abnormalities after i.p. injection. The obtained results indicate that 2,4-D is genotoxic in mice in vivo under the conditions tested. Hence, more care should be given to the application of 2,4-D on edible crops since repeated uses may underlie a health hazard.

Cytogenetic studies on the effect of feeding mice with stored wheat grains treated with malathion.

The cytogenetic effect of malathion residues in wheat grains stored for different periods of time (4, 12, 24 weeks) was evaluated in Swiss mice. The studies included: (1) chromosomal aberrations analysis in bone-marrow and spermatocyte cells; (2) chromosomal aberrations and sister chromatid exchange (SCE) analysis in spleen cell culture from mice fed with stored wheat grains. The tested doses were 8.36 (applied dose), 25.08 and 41.80 mg malathion kg(-1) wheat grains. The results demonstrated that the cytogenetic effect induced in different mouse tissues by malathion residues was dose-dependent and increased with increasing of both feeding and storage periods. Feeding mice with wheat grains stored for 4 weeks had a non-significant effect with respect to the induction of chromosomal aberrations or SCEs. Significant chromosome damage and increase of SCEs were observed in mice fed with wheat grains stored for 12 weeks. The maximum effect was recorded in mice fed for 12 weeks with the grains treated with the highest tested dose and stored for 24 weeks. However, mitomycin C i.p.-injected in mice at 1 mg kg(-1) body weight (b.w.) (positive control) induced a higher effect. The percentage of chromosome aberrations reached 13.60+/-0.98, 13.60+/-0.77 and 11.73+/-0.98 (P<0.01) in bone-marrow, cultured spleen cells and spermatocytes, respectively. The significant increase of abnormalities in spermatocytes was seen for univalent formation only, predominantly of the sex chromosomes. The frequency of SCEs was 10.76+/-0.62 per cell (P<0.01) in cultured spleen cells compared with 5.46+/-0.45 per cell for control and 14.66+/-0.54 per cell for the positive control. The obtained results indicate that malathion residues in stored wheat grains have potential genotoxic effect in mice under the conditions tested.

Cytological and Morphological Effects of the Insecticide N-methyl-l-naphthyl Carbamate “Sevin”

Summary The present investigation aimed to elucidate the effect of the insecticide “Sevin” on mitosis of Vicia faba and Gossypium barbadense as well as on some morphological aspects of germenation. Germinability of seeds of various crops was decreased by soaking the seeds in a saturated solution of “Sevin”. The decrease in germinability is greater as the time of soaking increases. Root-treatments (0,1 ppm. 100 ppm) as well as seed-soak treatment in saturated solution of the insecticide caused inhibition of primary root-length, and decrease in the percentage of shoot energence of Vicia faba . It was found that the mitotic index of Vicia faba decreased with increase of the concentration of “Sevin” solutions (0,25 sat. “25 ppm.” — sat. soln “100 ppm”) after root-treatments, while soaking seeds in saturated solution for 6—48 hour durations did not show amy significant effect. Abnormalities were induced in the mitosis of Vicia faba and Gossypium barbadense after “Sevin” application. The percentage of these increased with concentration and length of treatment.

Cytological effects of the insecticide tetrachlorvinphos

The effect of the organophosphorus insecticide tetrachlorvinphos (Gardona) has been studied on the mitosis and meiosis of Vicia faba, using the pure insecticide. An aqueous saturated solution of tetrachlorvinphos affected neither mitosis (after seed-soak and root treatment) nor meiosis (after spraying the plants at the flowering stage). The obtained results may be attributed to the low solubility of tetrachlorvinphos. A saturated solution of tetrachlorvinphos in Tween-60: water mixture (1:99) induced a statistically significant percentage of abnormal cells in root-tip meristems after root treatment for 4 h. Chromosome stickiness, disturbed meta- and anaphases and anaphase bridges were observed.

The Effect of 1-Naphthyl-n-Methyl Carbamate “Sevin” on Germination, Growth and Yield of Cotton Plant

Summary The effect of the insecticide 1-naphthyl-n-methyl carbamate “Sevin” on cotton plant was studied. Soaking of seeds in saturated solution for different periods (one to three days), was followed by inhibition of seedling emergence, plant growth and yield. Spraying with saturated and 0.5 saturated solutions of “Sevin”, applied weekly or every other week, did not show any injurious effect but slight inhibition of foliar growth in some cases. Enhancement of flowering and fruiting was reported by a weekly spray application with saturated and 0.5 saturated solutions. This was followed by a higher degree of fruit abscission and higher yield (Lint, seed, and lint seed/plant) than the control. This effeet was attributed to the thinning of the plants.