Histopathological and ultrastructural effects of delta-endotoxins of Bacillus thuringiensis serovar israelensis in the midgut of Simulium pertinax larvae (Diptera, Simuliidae)
Mem. Inst. Oswaldo Cruz
; 99(5): 493-498, Aug. 2004. ilus
Article
in En
| LILACS, SES-SP
| ID: lil-386680
Responsible library:
BR1.1
RESUMO
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 black fly 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 black fly larvae.
Full text:
1
Collection:
01-internacional
Database:
LILACS
/
SES-SP
Main subject:
Simuliidae
/
Bacillus thuringiensis
/
Digestive System
/
Insecticides
Limits:
Animals
Language:
En
Journal:
Mem. Inst. Oswaldo Cruz
Journal subject:
MEDICINA TROPICAL
/
PARASITOLOGIA
Year:
2004
Document type:
Article
Affiliation country:
Brazil