Histopathological and ultrastructural effects of δ-endotoxins of Bacillus thuringiensis serovar israelensis in the midgut of Simulium pertinax larvae (Diptera, Simuliidae)

被引:28
作者
Cavados, CFG
Majerowicz, S
Chaves, JQ
Araújo-Coutinho, CJPC
Rabinovitch, L
机构
[1] Fiocruz MS, Inst Oswaldo Cruz, Dept Bacteriol, BR-21045900 Rio De Janeiro, Brazil
[2] Fiocruz MS, Inst Oswaldo Cruz, Dept Virol, BR-21045900 Rio De Janeiro, Brazil
[3] Secretaria Saude Estado Sao Paulo, Sao Paulo, Brazil
来源
MEMORIAS DO INSTITUTO OSWALDO CRUZ | 2004年 / 99卷 / 05期
关键词
Bacillus thuringiensis serovar israelensis; Simulium pertinax; midgut; histopathology; ultrastructure;
D O I
10.1590/S0074-02762004000500006
中图分类号
R38 [医学寄生虫学]; Q [生物科学];
学科分类号
07 ; 0710 ; 09 ; 100103 ;
摘要
The bacterium Bacillus thuringiensis (Bt) produces parasporal crystals containing delta-endotoxins responsible for selective insecticidal activity on larvae. Upon ingestion, these crystals are solubilized in the midgut lumen and converted into active toxins that bind to receptors present on the microvilli causing serious damage to the epithelial columnar cells. We investigated the effect of these endotoxins on larvae of the Simulium pertinax, a common blackfly in Brazil, using several concentrations during 4 h of the serovar israelensis strain IPS-82 (LFB-FIOCRUZ 584, serotype H-14 type strain of the Institute Pasteur Paris. Light and electron microscope observations revealed, by time and endotoxin concentration, increasing damages of the larvae midgut epithelium. The most characteristic effects were midgut columnar cell vacuolization, microvilli damages, epithelium cell contents passing into the midgut lumen and finally the cell death. This article is the first report of the histopathological effects of the Bti endotoxins in the midgut of S. pertinax larvae and the data obtained may contribute to a better understanding of the mode of action of this bacterial strain used as bioinsecticide against blackfly larvae.
引用
收藏
页码:493 / 498
页数:6
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