Revista Cubana de Medicina Tropical
On-line version ISSN 1561-3054
DIAZ, Cristina; RODRIGUEZ, María Magdalena; FRESNEDA, Mario and BISSET, Juan A. Determinación de la actividad glutatión-S-transferasa en cepas de Culex quinquefasciatus de Cuba y otros países de América Latina. Rev Cubana Med Trop [online]. 2004, vol.56, n.2, pp. 111-116. ISSN 1561-3054.
In the present paper, we standardized a microtitration assay for the determination of specific activity of glutathione-S-transferase using a Culex quinquefasciatus strain selected in lab with pyrethroid insecticide lambdacyhalothrin for 6 generations (SP6). The saturation values for reduced glutathione and 1-chlorine 2,4-dinitrobenzene were 15 mM and 40 mM, respectively; we also estimated that 3 minutes was the optimal time in order to differentiate resistant strain SP6 from the susceptible reference strain S-Lab (p>0.05). Additionally, the optimized microtitration method allowed testing 4 Culex strains from Cuba (SANTIAGO DE CUBA, SD4, QUIBU AND SP6), one from Venezuela (MIRANDA), one from Colombia (MEDELLIN) and the other from Brazil (RIO DE JANEIRO) for glutathione-S-transferase activity. MIRANDA showed the highest activity for this detoxifying enzyme. However, the mechanism of detoxyfication in all the strains was very unfrequent, which indicates that its role in resistance to insecticide for all the studied strains is not so important. Glutathione-S-transferase values were compared with non-specific esterase and altered acetylcholinesterase frequencies for each of the studied strains
Keywords : Optimization; mechanisms of insecticide resistence; gluthation- S-transferase.