Biochemical characterization of α-amylase and digestive Glucosidase in the pistachio red bug, Lygaeus pandurus (Hemiptera: Lygaeidae)

Document Type : Agricultural Entomology

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Abstract

The pistachio red bug, Lygaeus pandurus is one of the most destructive true bugs of pistachio in Kerman province. In order to better understanding about the nutritional physiology of the pest, after dissecting adults under stereomicroscope their midguts and salivary glands were removed. The tissues were homogenized and centrifuged and the supernatants were used as the enzyme source in subsequent experiments. Using specific substrates, carbohydrase activity and some of their characteristics were determined. The optimal pH for activity of a- amylase in the midgut and salivary glands were 5 and 6, respectively. Maximum activity of a- and b- glucosidase were observed at pH 5 in the midgut and at pH 5 and 6, in salivary glands, respectively. Optimal temperature for a-amylase activity in midgut and salivary glands obtained 50 and 40 °C, respectively. Midgut α- and β-glucosidase were optimally active at 45 °C and maximum activity of a and b-glucosidase in salivary glands were determined at 30 and 35 °C, respectively. Midgut a-amylase activity of this pest decreased in presence of Ca2+,Mg2+ andEDTA. Midgut α-glucosidase activity was highest in the presence of Ca2+. In contrast, Mg2+ increased midgut b-glucosidase activity. Zymogram analysis showed one form of a-glucosidase and one form of b-glucosidase in both midgut and salivary glands of this pest. Two isoforms of a-amylase were detected in salivary glands and three isoforms of a-amylase in midgut of this pest.

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Applied Entomology and Phytopathology
Volume 82, No. 1
September 2014
Pages 53-66

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