Biochemical characterization of α‐amylase of the Sunn pest, Eurygaster integriceps

Abstract

The α-amylase in the midgut and salivary glands of Eurygaster integriceps was isolated and characterized. The specific activity of α-amylase in the midgut was 1.77 U/mg protein and in the salivary glands was 1.65 U/mg protein. Sodium dodecylsulfate electrophoresis showed that both midgut and salivary glands contain isozymes. Only a trace amount of α-amylase activity was detected in the first nymphal stage (0.19 U/ mg protein), whereas α-amylase activity was highest in the third nymphal stage (1.21 U/mg protein). The results show that α-amylase activity in the immature stages increase constantly to the third instar stage. There was no significant difference in enzyme activity between the third, fourth and fifth nymphal stages and adults. The optimum pH and temperature for the enzyme activity was determined to be 6.5 and 35°C, respectively. The enzyme activity was inhibited by addition of ethylenediaminetetraacetic acid, urea, sodium dodecylsulfate and Mg 2+ , but NaCl and KCl enhanced enzyme activity.

A Study on the Toxicity of a Medicinal Plant, Artemisia Annua L. (Asteracea) Extracts to the Sunn Pest, Eurygaster Integriceps Puton (Hemiptera: Scutelleridae)

“…The insects, sunn pest (E. integriceps), were collected from the Karaj wheat farm of Tehran Province of Iran and reared on wheat grains in the laboratory at 27±2°C under a 14 h light : 10 h dark (LD 14 : 10) photoperiod (Kazzazi et al 2005).…”

Impact of Eurygaster maura (Heteroptera: Scutelleridae) Feeding on Quality of Bread Wheat in Relation to Attack Period

“…cause a reduction of wheat quality when they insert their piercing-sucking mouthparts in the kernels and extract the substances within. In order to facilitate the suction of the nutritional elements of the endosperm, the kernels are digested externally by injecting saliva rich in proteases (Sivri et al 1998;Konarev et al 2011) and amylases (Kazzazi et al 2005). The detrimental effect of such proteases on baking quality is very high, even when only 3-5% of kernels are damaged, and dramatically increases for values higher than 10% (Karababa and Ozan 1998;Hariri et al 2000).…”

Biochemical characterisation of α-amylase in two aphid species, Aphis fabae Scopoli (Hemiptera: Aphididae) and A. gossypii Glover (Hemiptera: Aphididae)

“…The effects of temperature and pH on α-amylase activity were examined using enzyme extract from the aphids as described by Kazzazi et al (2005). Optimal pH was determined by using universal buffer (0.02M) (citrate, phosphate, and borate) with pH set at 3, 4, 5, 6, 7, 8, 9, 10, 11, and 12.…”

“…Using enzyme inhibitors to control insect pest has already been demonstrated to be an important system for the insect pest control since these inhibitors have detrimental effects on the insect growth and development by interfering in food digestion (Confalonieri et al 1998). α-Amylase activity has been described from different species of several insect orders including Orthoptera, Coleoptera, Hymenoptera, Diptera, Lepidoptera, and Hemiptera (Baker & Woo 1985;Terra et al 1988;Mendiola-Olaya et al 2000;Zeng & Cohen 2000;Oliveira-Neto et al 2003;Kazzazi et al 2005;Safaei-Khorram et al 2010;. α-Amylases are important enzymes involved in carbohydrate metabolism in insects, thus α-amylase inhibitors should be used in the control of agricultural pest.…”