Proteolytic gut activities in the rice water weevil, Lissorhoptrus brevirostris Suffrian (Coleoptera: Curculionidae)

Abstract

Digestive endoprotease activities of the rice water weevil, Lissorhoptrus brevirostris Suffrian (Coleoptera: Curculionidae), were characterized based on the ability of gut extracts to hydrolyze specific synthetic substrates, optimal pH, and hydrolysis sensitivity to protease inhibitors. Larvae of this species were found to use a complex proteolytic system that includes cathepsin D-, cathepsin B-, trypsin-, and chymotrypsin-like activities. Trypsin-like activity was evenly distributed among the anterior, middle, and posterior portions of the gut, whereas cathepsin B- and cathepsin D-like activities were mainly located in the anterior and middle sections, and the chymotrypsin-like activity was highest in the middle and posterior sections. Gelatin-containing native-PAGE gels indicated the presence of several aspartyl, cysteine, and serine protease forms and confirmed the spatial organization of the proteolytic digestive process.

Partial characterization of the proteolytic enzymes in the gut of the banana weevil, Cosmopolites sordidus, and effects of soybean Kunitz trypsin inhibitor on larval performance

“…Our results suggest that protein digestion might be initiated by different types of endoproteases located in the anterior section of the gut, and continued by exopeptidases in subsequent steps of the hydrolytic process. This distribution contrasts with that of L. brevirostris larvae, in which cathepsin D‐ and cathepsin B‐like activities were mainly located in the anterior and middle sections of the gut, chymotrypsin‐like activity was higher in the middle and posterior sections, and trypsin‐like activity was evenly distributed along the gut (Hernández et al., 2003).…”

“…There are also some curculionids with serine protease activity and alkaline pH optima, such as the red palm weevil, Rhynchophorus ferrugineus (Alarcon et al., 2002), and the citrus weevil, Diaprepes abbreviatus (Yan et al., 1999). Most species have a digestive system based on proteases of various mechanistic classes: serine, cysteine, and aspartyl proteases have been identified in the guts of the rice weevil, Sitophilus oryzae (Baker, 1982; Liang et al., 1991; Alfonso Rubí et al., 2003), and the rice water weevil, Lissorhoptrus brevirostris (Hernández et al., 2003); serine and cysteine proteases in the weevil Baris coerulescens (Bonadé‐Bottino et al., 1999) and the cabbage seed weevil, Ceutorhynchus assimilis (Girard et al., 1998); and serine and aspartyl proteases in a sugar beet weevil, Aubeonymus mariaefranciscae (Ortego et al., 1998). Carboxypeptidases and aminopeptidases have also been reported in several species of curculionids (Baker, 1982; Ortego et al., 1998).…”

“…Actually, multiple serine, cysteine, and aspartyl protease forms, as determined by gelatin containing SDS‐PAGE gels, have been determined in gut extracts of C. sordidus adults. Multiple protease forms have also been found in the midguts of O. sulcatus (Michaud et al., 1995), C. assimilis (Girard et al., 1998), and L. brevirostris (Hernández et al., 2003).…”

“…Because of the diversity of insect digestive proteases (Wolfson & Murdock, 1990) and the physiological adaptations of some insect species to ingested hydrolytic enzyme inhibitors (Jongsma & Bolter, 1997), it is necessary to study in detail the major digestive enzymes present in a particular species and their interaction with appropriate inhibitors. Complex proteolytic systems for protein digestion, based on the presence of endoproteases of different mechanistic classes and exopeptidases, appear to be widespread among curculionids (Ortego et al., 1998; Bonadé‐Bottino et al., 1999; Hernández et al., 2003). However, apart from the cysteine protease activity identified in the midgut of the banana weevil (Kiggundu et al., 2003b), the nature of the digestive proteases repertoire in this species is largely unknown.…”

Transcriptional regulation in cowpea bruchid guts during adaptation to a plant defence protease inhibitor

“…They belong to the papain superfamily (Turk et al ., 1997). Cathepsin‐like cysteine proteases are common in midguts of Hemiptera, Diptera and Coleoptera (Terra & Ferreira, 1994; Yan et al ., 2002; Hernandez et al ., 2003). Cathepsin B is unique in this family because it has both endo‐ and exo‐peptidase activities.…”