Alterations in the fat body and midgut of Culex quinquefasciatus larvae following exposure to different insecticides.
This study describes morphological alterations in the fat body and midgut of Culex quinquefasciatus larvae following exposure to different insecticides. To this end, both third and fourth instars of C. quinquefasciatus larvae were exposed for 30 and 60 min to organophosphate (50 ppb), pyrethroids (20 and 30 ppb), and avermectin derivates (1.5 and 54 ppb). Following incubation, pH measurements of the larvae gut were recorded. The fat body and midgut were also analyzed by light and transmission electron microscopy. These studies demonstrate a decrease in the pH of the larvae anterior midgut following exposure to all of the tested insecticides. Histochemical tests revealed a strong reaction for neutral lipids in the control group and a marked decrease in the group exposed to cypermethrin. Furthermore, a weak reaction with acidic lipids in larvae exposed to deltamethrin, temephos, ivermectin and abamectin was also observed. Insecticide-exposed larvae also exhibited cytoplasm granule differences, relative to control larvae. Finally, we noted a small reduction in microvilli size in the apex of digestive cells, although vesicles were found to be present. The destructive changes in the larvae were very similar regardless of the type of insecticide analyzed. These data suggest that alterations in the fat body and midgut are a common response to cellular intoxication.
Alves
Stênio Nunes
SN
Universidade Federal de São João del-Rey - Campus Centro-Oeste Dona Lindu, Brazil.
Serrão
José Eduardo
JE
Melo
Alan Lane
AL
D000818:Animals; D003465:Culex / Q000166:cytology* / Q000187:drug effects*; D005216:Fat Body / Q000166:cytology* / Q000187:drug effects*; D006651:Histocytochemistry; D007306:Insecticides / Q000494:pharmacology*; D007422:Intestines / Q000166:cytology / Q000187:drug effects; D007559:Ivermectin / Q000031:analogs & derivatives / Q000494:pharmacology; D007814:Larva / Q000166:cytology / Q000187:drug effects; D008853:Microscopy; D008855:Microscopy, Electron, Scanning; D011722:Pyrethrins / Q000494:pharmacology
D007306:Insecticides; D011722:Pyrethrins; D007559:Ivermectin; C019264:avermectin