Autor(es):
Roma, Gislaine Cristina [UNESP] ; de Souza, Leonardo Peres [UNESP] ; Brienza, Paula Desjardins [UNESP] ; Scopinho Furquim, Karim Christina [UNESP] ; Bechara, Gervasio Henrique [UNESP] ; Camargo-Mathias, Maria Izabel [UNESP]
Data: 2014
Identificador Persistente: http://hdl.handle.net/11449/20047
Origem: Oasisbr
Assunto(s): Rhipicephalus sanguineus; Ticks; Permethrin; Ecdysteroids; Reproduction; Rhipicephalus sanguineus; Rhipicephalus sanguineus; Ticks; Ticks; Permethrin; Permethrin; Ecdysteroids; Ecdysteroids; Reproduction; Reproduction
Descrição
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
As recent studies have shown that ecdysteroids may play a major role in the regulation of vitellogenesis in Ixodidae, the present study quantified, by means of a radioimmunoassay, the levels of ecdysteroids present in the hemolymph of semi-engorged females of Rhipicephalus sanguineus ticks obtained from control females (exposed to distilled water) and those exposed to increasing concentrations of permethrin. The levels of ecdysteroids decreased significantly as the concentration of permethrin increased, suggesting that this compound could be an inhibitor of ecdysteroids secretion, and consequently interfering with the reproductive ability of these ticks, since this hormone is responsible for the synthesis and incorporation of vitellogenin by oocytes. This study complements the previous results with R. sanguineus semiengorged females, showing that permethrin is a potent agent causing major morphological changes in tick oocytes, such as the appearance of large vacuoles in the cytoplasm, reduction in the amount of yolk granules and a decrease in oocyte size, thus culminating in cell death and consequently reducing or preventing reproduction in treated females. The findings that permethrin leads to a decrease in ecdysteroid titers could represent an entry step into this scenario. (C) 2012 Elsevier B.V. All rights reserved.
Univ Estadual Paulista, UNESP, Dept Biol, Inst Biociencias, BR-13506900 Rio Claro, SP, Brazil
UNESP, Fac Ciencias Agr & Vet, Dept Patol Vet, BR-14884900 Jaboticabal, SP, Brazil
Univ Estadual Paulista, UNESP, Dept Biol, Inst Biociencias, BR-13506900 Rio Claro, SP, Brazil
UNESP, Fac Ciencias Agr & Vet, Dept Patol Vet, BR-14884900 Jaboticabal, SP, Brazil
FAPESP: 07/57809-5
FAPESP: 07/59020-0
FAPESP: 09/54125-3
CNPq: 308733/2006-1
