Characterization of Esterases in a Brazilian Population of Zaprionus Indianus (Diptera: Drosophilidae)

Abstract

The aim of this study was to characterize esterases in Zaprionus indianus, a drosophilid recently introduced into Brazil. A further aim was study the variation of activity of esterases in the presence of inhibitors and their expression according to sex, sexual activity and age of individual flies. Polymorphisms were detected in two esterase loci (Est-2 and Est-3) and monomorphisms in four others (Est-1, Est-4, Est-5 and Est-6). Biochemical tests using alpha- and beta-naphthyl acetate and the inhibitors malathion, eserine sulphate and PMSF allowed us to classify EST-2 and EST-5 as beta-esterases, both carboxyl-esterases, and EST-1, EST-3, EST-4 and EST-6 as alpha-esterases. EST-1 and EST-3 were classified as carboxyl-esterases and EST-4 and EST-6 as cholinesterases. EST-5 activity was more pronounced in males and EST-2 was restricted to them or to recently copulated females. EST-4, rarely detected, was not characterized. Based on their biochemical characteristics possible roles for these enzymes are suggested.

Scenario of the spread of the invasive species Zaprionus indianus Gupta, 1970 (Diptera, Drosophilidae) in Brazil

“…Individuals were collected with traps containing enticing baits made up of banana and biological yeast, as described by Galego et al (2006). Figure 1 shows the scatterplot of the locations of the populations sampled, with the enclosing convex polygon overlaid by the map of Brazil.…”

“…Electrophoresis was carried out in a Tris-glycine buffer pH 8.8 at 200 V for 3 h. A random sample of 20 individuals (10 males and 10 females) from each population was used. In the case of the EST2 system, which is restricted to males (Galego et al , 2006), only 10 individuals were analyzed. Detection of the esterases (EST) was undertaken as suggested by Galego et al (2006).…”

“…Since esterases appear to be the most polymorphic loci in Brazilian Z. indianus populations (Mattos-Machado et al , 2005; Galego et al , 2006; Galego and Carareto, 2007), Est2 and Est3 loci were chosen for inferring the spreading dynamics of Z. indianus regionwise.…”

Evaluation of the Effects of a Single Exposure to Ethidium Bromide in Drosophila melanogaster (Diptera-Drosophilidae)

“…The extracts were centrifuged at 10.000 rpm using a MiniSpin (Eppendorf) centrifuge for 3 min. For electrophoresis we used 10 lL of the extract and 0.1M Tris-Glicine pH 8.3, setting the voltage to 180 V during 4 h. The gels were stained using twice: first for alpha and beta-naphthyl esterase activity, using a and bnaphthyl acetate as substrates, according to Galego et al (2006) for 90 min. After that, the gel was submerged in a solution of 20% ethyl alcohol and 20% acetic acid for 1 h, and subsequently stained with Coomassie Brilliant Blue R-250.…”

PHYLOGENETIC RELATIONSHIP OF AN INVASIVE DROSOPHILID, Zaprionus indianus AND CLOSELY RELATED SPECIES OF DROSOPHILIDAE (DIPTERA) BASED ON ESTERASE PATTERNS

“…So, electrophoresis separation of isozymes has been widely used both in taxonomic and genetic studies in Drosophila. In this regard, Galego et al (2006) described six loci coding for esterases in Z. indianus, four of which encode α-esterases and two encode β-esterases. Two of these loci, Est-3 (four alleles) and Est-2 (two alleles), were polymorphic.…”