title: Functional and translational analyses of a beta-glucosidase gene (glycosyl hydrolase family 1) isolated from the gut of the lower termite Reticulitermes flavipes.
abstract: This research focused on digestive beta-glucosidases from glycosyl hydrolase family (GHF) 1 from the gut of the lower termite Reticulitermes flavipes. In preceding studies on R. flavipes, we characterized beta-glucosidase activity across the gut and its inhibition by carbohydrate-based inhibitors, and subsequently we identified two partial beta-glucosidase cDNA sequences from a host gut cDNA library. Here, we report on the full-length cDNA sequence for one of the R. flavipes beta-glucosidases (RfBGluc-1), the expression of its mRNA in the salivary gland and foregut, the production of recombinant protein using a baculovirus-insect expression system, optimal recombinant substrate specificity profiles and parameters, and significant inhibition by the established beta-glucosidase inhibitor cellobioimidazole. We also report the partial cDNA sequence for a second gut beta-glucosidase (RfBGluc-2), and show that like RfBGluc-1 its mRNA is localized mainly in the salivary gland. Other results for RfBGluc-1 showing activity against laminaribose, a component of microbial cell walls, suggest that RfBGluc-1 may serve dual functions in cellulose digestion and immunity. These findings provide important information that will enable the testing of hypotheses related to collaborative host-symbiont lignocellulose digestion, and that contributes to the development of next-generation termiticides and novel biocatalyst cocktails for use in biomass-to-bioethanol applications.
authors.affiliation: Entomology and Nematology Department, University of Florida, PO Box 110620, Gainesville, FL 32611-0620, USA. mescharf@ufl.edu
authors.forename: Michael E
authors.initials: ME
authors.lastname: Scharf
authors.forename: Elena S
authors.initials: ES
authors.lastname: Kovaleva
authors.forename: Sanjay
authors.initials: S
authors.lastname: Jadhao
authors.forename: James H
authors.initials: JH
authors.lastname: Campbell
authors.forename: George W
authors.initials: GW
authors.lastname: Buchman
authors.forename: Drion G
authors.initials: DG
authors.lastname: Boucias
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D004795:Enzyme Stability; D041981:Gastrointestinal Tract / Q000737:chemistry / Q000201:enzymology; D019476:Insect Proteins / Q000737:chemistry / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism*; D020049:Isoptera / Q000737:chemistry / Q000201:enzymology* / Q000235:genetics; D007700:Kinetics; D008969:Molecular Sequence Data; D014176:Protein Biosynthesis; D012469:Salivary Glands / Q000737:chemistry / Q000201:enzymology; D016415:Sequence Alignment; D001617:beta-Glucosidase / Q000737:chemistry / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism*
chemical_list: D019476:Insect Proteins; D001617:beta-Glucosidase