Tissue-specific expression of esterases in Triatoma infestans (Triatominae, Heteroptera)

Abstract

We examined the esterases present in the hemolymph and Malpighian tubules of "Kissing bug", Triatoma infestans (Triatominae, Heteroptera) by polyacrylamide gel electrophoresis. Six esterase bands were observed and were designated EST 1 to EST 6. EST 1, 4, 5 and 6 were exclusive to hemolymph, whereas EST 2 and 3 were found only in Malpighian tubules. Each tissue had a characteristic esterase pattern, which may be related to its functional role. The four hemolymph esterases hydrolyzed a-naphthyl acetate. One of these enzymes was classified as a carboxylesterase (EST 4), and another was an acetylesterase (EST 6). The other two enzymes (EST 1 and 5) could be either carboxylesterases or serino-proteases with an esterolytic function, as they were selectively inhibited by phenylmethylsulfonyl fluoride (PMSF). Absence of genetic variability could be due to high inbreeding.<br>Foram examinadas as esterases presentes na hemolinfa e nos túbulos de Malpighi do "barbeiro" Triatoma infestans (Triatominae, Heteroptera) através de eletroforese em gel de poliacrilamida. No total, foram observadas seis bandas esterásicas denominadas EST 1 a EST 6. As esterases EST 1, 4, 5 e 6 foram exclusivas da hemolinfa, enquanto EST 2 e 3 foram encontradas apenas nos túbulos de Malpighi. Cada tecido apresentou um padrão esterásico característico, o qual pode estar relacionado com o seu papel funcional. As quatro esterases da hemolinfa hidrolizaram o a-naftil acetato. Uma destas enzimas foi classificada como carboxilesterase (EST 4), uma como acetilesterase (EST 6) e as outras duas enzimas podem ser carboxilesterases ou serino-proteases com função esterolítica, uma vez que elas foram inibidas seletivamente pelo PMSF (EST 1 e 5). A ausência de variabilidade genética pode ser devida à alta taxa de endocruzamentos

Genetic variability in esterases and the insecticide resistance in brazilian strains ofOryzaephilus mercatorandOryzaephilus surinamensis(Coleoptera: Silvanidae)

“…Therefore, it is possible that OmEST-1 is a non-cholinergic cholinesterase and that it plays a role in this greater resistance. Non-cholinergic cholinesterases have already been verified in other species, such as the EST-9 in D. melanogaster (Healy et al ., 1991) and the EST-2 in Triatoma infestans (Tavares et al ., 1998). In addition to OmEST-1, OmLA presented a higher inhibition pattern of OmEST-3 and OmEST-4 exposed to malathion and chlorpyrifos-methyl in relation to the most sensitive strains.…”

Esterase patterns in species of the triatome bugRhodnius

“…Members of the Triatominae subfamily have been analysed genetically with respect to several enzymatic systems (Dujardin & Tibayrenc, 1985; Dujardin et al , 1987, 1998; Frías & Kattan, 1989; García et al , 1995; Lopez & Moreno, 1995). In general, these studies have shown that monomorphism is a common characteristic among this group (Pereira et al , 1996; Brenière et al , 1997; Tavares et al , 1998; Soares et al , 1999; Monteiro et al , 2002). The aim of this work is to compare esterase patterns in Rhodnius domesticus , Rhodnius robustus and Rhodnius neivai in order to add more information about genetic variability and relationships among these species.…”

Changes in activity of non-specific esterases in cadmium treated Lymantria dispar larvae

“…Esterases are a group of highly polymorphic and multifunctional hydrolytic enzymes. So far, four different classes of esterases have been detected: arylesterase, acetylcholinesterase, carboxylesterase and cholinesterase (Tavares et al 1998). Each class is defined by its sensitivity to inhibitors, substrate specificity, and the specific amino acid composition of the active centers.…”