Cytogenetical studies on the effects of some chlorinated pesticides. III. Concluding remarks.

Abstract

The use of pesticides is unavoidable in modern agriculture . Several million tons of organic and inorganic chemicals with antimicrobial and insecticidal properties are added an nually in soil and their environment.Some of them while killing or inhibiting the harmful or ganisms not only upset the ecosystem but also produce undesirable changes in higher organisms. The present study was undertaken in order to assess the cytogenetic effects of some widely used chlorinated pesticides-Benzene hexachloride (BHC), Lindane, Aldrin, Heptachlor and Endrin on plant system. Meterial and methodsThe detailed methodology has been described in Part I and II (1987) of this series.Results and discussion A) Effect on somatic chromosomesThe immediate effect of all the pesticide treatment was partial or entire inactivation of spin dle mechanism followed by scattering of chromosomes. Benzene hexachloride (BHC) has been observed to affect spindle apparatus more severely than Lindane, Aldrin, Heptachlor and Endrin. The spindle inactivation affected the chromosomes movement. The various theories which have been put forwarded to explain chromosomes movement during cell division does not seems to be entirely satisfactory. The various pesticides were differently potent in disturbing the spindle apparatus. No normal metaphase stage was observed after 2hr. root-tip treatment of BHC, while in Lindane and Endrin treatment stages were observed in low magnitude (data not presented here). The normal metaphase stages were observed in higher percentage after Aldrin and Heptachlor treatment in compare to BHC, Lindane and Endrin treatments for the same duration of treatment (data not presented here). In Aldrin and Heptachlor treatments the concentrations used were ten times greater than BHC, Lindane and Endrin treatments. There fore, alteration in viscosity of karyolymph will be greater in Aldrin and Heptachlor treated root tips than BHC, Lindane and Endrin treated. Hence, as per viscosity and hydration theory (Wassermann 1929), no normal cell would be observed in Aldrin and Heptachlor treated root tins: however, normal cells were observed in all the treatments.The chromosome autonomy theory (Frey-Wyssling 1938) seems partially responsible for chromosome movement as the chromosomes possess energy in the form of adenosine triph osphate (ATP) necessary for their movement. Epel (1963) found complete inhibition of mitosis when ATP level dropped below the 50% of normal level. Hence, it may be presumed that the chemicals which affect ATP and sugar synthesis by creating annoxia condition or by other means exert much effect on chromosomes movement. The oxygen defficiency is known to

Mutagenicity and genotoxicity of dicapthon insecticide

“…Dicapthon significantly decreased MI in a dose dependent manner. Decreasing of the MI could be due to decreasing ATP level and the pressure from the functioning of the energy production center (Epel 1963;Jain and Andsorbhoy 1988), blocking of G2 preventing the cell from entering mitosis ( Van't Hof 1968), inhibition of certain cell cycle specific enzymes such as DNA polymerase, which is necessary for the synthesis of DNA precursors as well as other enzymes more directly involved with spindle production, assembly or orientation (Hidalgo et al 1989). The clastogenic response of various compounds is often associated with high toxicity (Müller and Sofuni 2000).…”

Evaluation of the cytogenetic damage induced by the organophosphorous insecticide acephate

“…The decrease of the MI could be due to blocking of G 2 , which prevents the cell from entering mitosis ( Van't Hof 1968) or it may be caused by a decrease in the ATP level and the stress from the energy-production centre (Epel 1963;Jain and Andsorbhoy 1988). Inhibition of certain cell cyle-specific proteins/ enzymes remains as a possible pesticide target that inhibits DNA synthesis or may inhibit spindle production, assembly or orientation (Hidalgo et al 1989).…”

The effects of boric acid on sister chromatid exchanges and chromosome aberrations in cultured human lymphocytes

“…This result also supports the cytotoxicity of BA. The decreasing of the MI or the inhibition of DNA synthesis might be caused by decreasing adenosine triphosphate (ATP) level and pressure from the functioning of the energy-production centre (Epel 1963;Jain and Andsorbhoy 1988).…”