Impact of abamectin and emamectin benzoate against terrestrial snail glutamate decarboxylase (GAD) activity

Document Type : Original Article

Authors

1 Faculty of Agriculture, Department of Pesticides Chemistry and Technology (Elshatby) Alexandria University

2 Agriculture Research Center (ARC), Plant Protection Institute

3 National Institute of Oceanography and Fisheries (NIOF), Central Laboratories Unit (CLU), Alexandria, Egypt

10.21608/jpces.2017.459307

Abstract

We investigated the in vivo effects of abamectin, emamectin benzoate and methomyl on - (GAD in Eobania vermiculatabrown garden snail (BGS) and Thebapisana white garden snail (WGS)). GAD activity was evaluated by measuring the formation of gamma aminobutyric acid after derivatization to phenylthiocarbamoyl GABA (PTC-GABA) using HPLC with UV absorbance detection at 245 nm.PTC-GABA and PTC-Glutamic acid were used as standards with retention times of 3.86 and 10.012, respectively. The results revealed thatboth abamectin and emamectin benzoate
markedly stimulated GAD activity in both types of the land snails. In contrast, methomyl clearly inhibited GAD activity in a dose-dependent manner. That the activity of GAD enzyme increased by decreasing the dose treatments in both types of snails. Inhibition of GAD activity was more pronounced in BGS than in WGS. Abamectin was more efficacious than emamectin benzoate in stimulating GAD activity, especially in WGS. The stimulatory effects decreased with time, with minimal stimulation observed in BGS at 72 hr with the lowest concentration used (1/10 of LD50). Noteworthy, the
expression level of GAD in BGS was higher than in WGS, indicating more participation of GABAergic system of Eobania vermiculata compared with Theba pisana in this respect. These findings may shed light on the mechanism by which abamectin and emamectin benzoate elevate the level of GABA neurotransmission in E. vermiculata and T. pisana land snails, as they activate the biosynthesis of GABA and inhibit its degradation.

Keywords

Journal of Pest Control and Environmental Sciences
Volume 22, Issue 1
2017
Pages 17-27

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