Purification and characterization of midgut α‐amylases ofEurygaster integriceps

Abstract

In the current study, midgut a-amylase from Sunn pest (Eurygaster integriceps Puton) (Hemiptera: Scutelleridae), one of the most serious pests of wheat and barley in the wide area of the Near and Middle East, West Asia, and many of the new independent states of central Asia, were purified and characterized. Amylase activity was detected in the midgut of the insects which were collected from both over-wintering sites during winter and feeding insects during spring. Amylase activities in the midgut of over-wintering and feeding insects were 5.71 and 3.43 U/mg protein, respectively. Initially, a native electrophoretic analysis of E. integriceps crude midgut extract showed that there are two major amylase forms in the midgut. Through the sequence of ammonium sulfate precipitation, first by gel filtration chromatography (Sephadex G-75), anion exchange chromatography (diethylaminoethylcellulose) and second by gel filtration chromatography, specific activity of a-amylase of E. integriceps increased 44-fold from approximately 3 to 133 U/mg protein. Analysis of purified amylases by sodium dodecylsulfate polyacrylamide gel electrophoresis showed that these proteins had estimated molecular masses of 49 and 52 kDa. Optimum temperature was determined to be 30-40°C. The optimum pH value was 6.5 and the Kmapp for soluble starch was 0.54%.

Overwintering strategies in the red mason solitary bee—physiological correlates of midgut metabolic activity and turnover of nutrient reserves in females of Osmia bicornis

“…In contrast to O. bicornis females, in potato beetles the amylases are inactive at the beginning of diapause but the transcripts increased as beetles entered the maintenance stage (Yocum et al 2009b). Many temperate zone insect species which diapause during winter time exhibit decreased digestive enzyme activity because of nonfeeding period and metabolism cost reduction (Socha et al 1997;Socha et al 1998;Bandani et al 2009;Yocum et al 2009a, b). Amylase activity pattern towards ingested carbohydrates varies slightly in O bicornis females compared with most other wintering species.…”

Morpho-functional characterization and esterase patterns of the midgut of Tribolium castaneum Herbst, 1797 (Coleoptera: Tenebrionidae) parasitized by Gregarina cuneata (Apicomplexa: Eugregarinidae)

“…The presence of amylase in the midgut of T. castaneum suggests that these enzymes are essential to the survival of the insect and other pests of stored grains that mainly feed on carbohydrates (Bandani et al, 2009;Cristofoletti et al, 2001;Sousa and Conte, 2013).…”

Secretion and formation of perimicrovillar membrane in the digestive system of the Sunn pest, Eurygaster integriceps (Hemiptera: Scutelleridae) in response to feeding

“…Sample preparation was based on the previously described methods with slight modifications (Habibi et al, 2008;Bandani et al, 2009). Adult females were individually immobilized by placing them on crushed ice (8-10 min), then they were dissected under steromicroscope (Nikon, Tokyo, Japan) in precold 215 mM NaCl and their alimentary canal was removed.…”