Effect of a Bt-based product (Vectobar) on esterases and phosphatases from larvae of the mosquito Aedes aegypti
Autor(es): Koodalingam, Arunagirinathan; Mullainadhan, Periasamy; Rajalakshmi, Arumugam; Deepalakshmi, Ramadoss; Ammu, Manoharan
Resumo: Bacillus thuringiensis (Bt)-based formulations possess potent insecticidal property, and they are being used in insect vector control programs all over the world. In this study, we examined the efficacy of a Bt-based product (Vectobar) on two developmental stages (fourth instar larvae and pupae) of the mosquito Aedes aegypti. Vectobar at a concentration of 0.25 ppm was found to inflict 100% mortality of fourth instar larvae of A. aegypti within 24 h. By contrast, this Bt-based product tested up to 2 ppm was not effective against the pupae of A. aegypti. The systemic effect of Vectobar was further assessed in the fourth instar larvae of A. aegypti by measuring the levels of total proteins and activity of two important marker enzymes: esterases and phosphatases. Exposure of the larvae to Vectobar at a lethal threshold concentration (0.05 ppm) significantly decreased the level of total protein (34%) as well as the activities of acetylcholinesterase (36%), alpha-carboxylesterase (34%) and alkaline phosphatase (49%). On the other hand, 40% increase in the level of acid phosphatase activity was recorded in these larvae. The Vectobar did not affect the level of beta-carboxylesterase activity in the larvae of A. aegypti. This investigation clearly demonstrates differential modulation in the activities of esterases and phosphatases in Vectobar exposed larvae of A. aegypti. (c) 2012 Elsevier Inc. All rights reserved.
Palavras-Chave: Mosquitoes; Biological control; Bt toxin; Proteins; Esterases; Phosphatases
Imprenta: Pesticide Biochemistry and Physiology, v. 104, n. 3, p. 267-272, 2012
Identificador do objeto digital: 10.1016/j.pestbp.2012.09.008
Descritores: Aedes aegypti - Biochemistry ; Aedes aegypti - Public health
Data de publicação: 2012
