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Identification and enzymatic characterisation of digestive glucosidases from gut of red palm weevil, Rhynchophorus ferrugineus (Olivier, 1790) (Coleoptera: Curculionidae)

Darvishzadeh, Ali, Bandani, Ali R.
Archives of phytopathology and plant protection 2013 v.46 no.10 pp. 1159-1167
Phoenix canariensis, Rhynchophorus ferrugineus, alpha-glucosidase, beta-glucosidase, calcium chloride, digestive enzymes, digestive physiology, foregut, hindgut, insects, magnesium chloride, midgut, pH, pests, potassium chloride, sodium chloride, temperature
Red palm weevil, Rhynchophorus ferrugineus (Olivier, 1790) (Coleoptera: Curculionidae) is a serious pest of date worldwide. Thus, damage to palms (almost exclusively to Phoenix canariensis Hort) has been recorded in various places. Thus, the aim of the current study was to investigate two major digestive enzymes of this insect, α-D-glucosidase and β-D-glucosidase. The results showed that α-D-glucosidase and β-D-glucosidase are present in the insect gut mainly in the midgut and hindgut but trace amounts of the both enzymes were found in the foregut. Optimum temperature for α- and β-glucosidases was found to be 50 and 40 °C, respectively, and pH values were 4.0. The activity of glucosidases were increased by NaCl and KCl and inhibited by some compounds such as MgCl₂ and CaCl₂. Kinetic parameters showed that Kₘ of α and β-D-glucosidases was 3.15 and 4.11 mM, respectively. Therefore, it is concluded that in this insect species, both α-glucosidase and β-glucosidase are active but with different amounts. Understanding of the digestive physiology and glucosidase activity of red palm weevil is important when new management strategies based on interfering in the gut physiology of the insects are devised.