Esterase activity and detection of carboxylesterase and phosphotriesterase in female desert locust Schistocerca gregaria (Forskal) in relation to tissues and ages

Abstract

General esterases activity in the different bodytissues of adult females of 2-day and 13-day-old Schistocerca gregaria (Forskal)were measured spectrophotometricaly and carboxylesterase and phosphotriesterasewere characterized by electrophoresis method. Esterase activities were studiedin the tissues of brain, fore-, mid-, hindgut and ovary of the two ages in thepresence of α-naphthyl acetate as a substrate and ethylenediamine tetraaceticacid (EDTA) and profenofos as inhibitors. Spectrophotometric analysis indicatedthat the esterase activity in adult S. gregaria tissues wassignificantly higher in the tissues of mid-, foregut, ovary and brain of2-day-old females than those of 13-day-old, respectively. Meanwhile, theactivity was greater in the hindgut tissue of 13-day-old females than in2-day-old ones. Non-denaturing polyacrylamide gel electrophoresis revealeddifferences in isozyme composition. Three to ten esterase bands were detectedin the different body tissues of the two ages of adult females. These bands werecharacterized as phosphotriesterase and carboxylesterase by using the twoinhibitors. Bands Est-1, Est-2, Est-3 and Est-6 were found to becarboxylesterase in the different tissues, while band Est-4 was only detectedto be phosphotriesterase.