Investigation of isoenzyme a-esterase in Aedes aegypti from two municipalities of Mato Grosso

DOI: 10.15343/0104-7809.20194304976995

Abstract

Esterases are groups of enzymes that increase the mechanism of action of insect vectors in their metabolic activity while under
environmental pressure. The aim of this study was to analyze the level of a-esterase expression in Aedes aegypti populations
in the municipalities of Cuiabá and Várzea Grande, MT as a way to contribute to vector research. Samples were collected
through ovitraps in each municipality and allele results were analyzed by factorial ANOVA between months, locations and
seasonal phase. The alleles of 385 Ae. aegypti individuals demonstrated the highest expressions during the ebb period,
significantly between months (F7,377=6.89; p<0.01) and between sites (F1,383=11.01). Expressed and superexpressed
alleles decreased in Mar/2016, during the “peak water” period and resumed from May/2016 to Nov/2016. Regarding the
frequency, expressed alleles increased in Várzea Grande, during the flood period with the highest precipitation. There was
an increasing tendency of the expressed alleles with precipitation and the frequency values between Oct/2015 (30%±88)
and Feb/2016 (89±55%); meanwhile, for the superexpressed alleles, this occurred during the ebb period (42±91%). Várzea
Grande specimens reached a higher frequency of expressed alleles (75±41.36%), but there was a reduction of overexpressed
alleles in both municipalities (F2,13=12.39; p<0.01). The results obtained in this study indicate that the esterase isoenzyme
method was sensitive enough to detect variations in allele frequency in natural Ae. aegypti populations, which implies an
increased metabolic activity over the period examined.