Hexachlorocyclohexane inhibits calmodulin-dependent Ca2+-ATPase activity in rice shoot membranes.

Salimath, P. V. and Sharada, R. and Karanth, N. G. K. and Shetty, H. S. and Majumder, S. K. (1988) Hexachlorocyclohexane inhibits calmodulin-dependent Ca2+-ATPase activity in rice shoot membranes. Pesticide Biochemistry and Physiology, 2. 146-154; 28 ref..

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Abstract

In a laboratory study, the inclusion of hexachlorocyclohexane (HCH) or calmodulin antagonists to the germination medium of rice paddy seeds retarded the growth of the plants and was accompanied by the in vivo inhibition of Ca2-ATPase activity. Bromophos had no significant effect on either plant growth or the enzyme activity. HCH inhibited Ca2+-ATPase activity in vitro and in vivo (IC50 = 20 M and 1.7 mM, resp.) in a dose-dependent manner. Chloropromazine also inhibited the enzyme activity in vivo (IC50 = 50-80 M). Plant growth retardation and enzyme inhibition caused by HCH were reversed when the insecticide was withdrawn from the germinating medium. Enzyme inhibition caused by either calmodulin antagonists or HCH was overcome by the addition of excess calmodulin to the assay system. The inclusion of crude calmodulin from rice shoots increased Ca2+-ATPase activity by 112%, suggesting the calmodulin-dependent regulation of the enzyme activity. The results demonstrate the role of Ca2+ and calmodulin in the regulation of plant growth and of Ca2+-ATPase activity, and suggest a possible phytotoxic mechanism of action of HCH in vivo.

Item Type:	Article
Uncontrolled Keywords:	Enzymes-; Adenosinetriphosphatase-; Growth-; Enzyme-inhibitors; Phytotoxicity-; Calcium-; Antiemetics-; Nontarget-effects; Rice-; insecticides-; effects-; HCH-; Bromophos-; Chlorpromazine-; Calmodulin-; antagonists-; Seed-treatment; Seed-germination; membranes-; metabolic-inhibitors; cereals-; agricultural-entomology
Subjects:	500 Natural Sciences and Mathematics > 04 Chemistry and Allied Sciences > 26 Pesticide Chemistry 600 Technology > 01 Medical sciences > 17 Toxicology
Divisions:	Food Protectants and Infestation Control
Depositing User:	Food Sci. & Technol. Information Services
Date Deposited:	15 Jun 2011 08:57
Last Modified:	28 Dec 2011 10:02
URI:	http://ir.cftri.res.in/id/eprint/8189

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