Cholinesterase activity during embryonic development in the blood-feeding bug Triatoma patagonica

E. C. VI SC I AR E L L I; C CHOPA; M I PICOLLO; A FERRERO

MEDICAL AND VETERINARY ENTOMOLOGY

WILEY-BLACKWELL PUBLISHING, INC

Lugar: Londres; Año: 2011 vol. 25 p. 297 - 301

0269-283X

Abstract. Triatoma patagonica Del Ponte (Hemiptera: Reduviidae), a vector ofChagas’ disease, is widely distributed in Argentina and is found in sylvatic andperidomiciliary ecotopes, as well as occasionally in human dwellings after thechemical control of Triatoma infestans. Anti-cholinesteratic products can be applied inperidomiciliary areas and thus knowledge of cholinesterase activity during embryonicdevelopment in this species might contribute further information relevant to effectivechemical control. Cholinesterase activity was characterized by reactions to eserine10−5 m, to increasing concentrations of substrate and to varying centrifugal speeds.Acetylcholinesterase activity was detected on day 4 and was significant fromday 5. A reduction in cholinesterase activity towards acetylthiocholine (ATC) wasobserved on days 9 and 10 of development. Cholinesterase activity towards ATC andbutyrylthiocholine (BTC) in homogenates of eggs was inhibited by eserine 10−5 m.The shape of the curve indicating levels of inhibition at different concentrations ofATC was typical of acetylcholinesterase. Activity towards BTC did not appear to beinhibited by excess substrate, which parallels the behaviour of butyrylcholinesterases.Cholinesterase activity towards ATC was reduced in supernatant centrifuged at15 000 g compared with supernatant centrifuged at 1100 g. The cholinesterase systemthat hydrolyzes mainly ATC seems to belong to the nervous system, as indicatedby its behaviour towards the substrates assayed, its greater insolubility and the factthat it evolves parallel to the development of the nervous system. Knowledge ofbiochemical changes associated with the development and maturation of the nervoussystem during embryonic development would contribute to the better understandingof anti-cholinesteratic compounds with ovicidal action that might be used in controlcampaigns against vectors of Chagas’ disease.