title: Comparative analysis of proteinase activities of Bacillus thuringiensis-resistant and -susceptible Ostrinia nubilalis (Lepidoptera: Crambidae).
abstract: Proteinase activities were compared in soluble and membrane fractions of guts obtained from larvae of Bacillus thuringiensis-resistant and -susceptible Ostrinia nubilalis. Overall, serine proteinases from soluble fractions of the susceptible strain were more active than those of the resistant strain. The soluble trypsin-like proteinase activity of the resistant strain was approximately half that of the susceptible strain. The number and relative molecular masses of soluble and membrane serine proteinases were different. However, there were no significant differences in the activities of serine proteinases and aminopeptidases extracted from midgut membranes of the two strains. Cry1Ab protoxin hydrolysis by soluble proteinase extracts of the resistant strain was reduced approximately 20-30% relative to that of the susceptible strain. Reduced protoxin processing due to decreased activities of Bt protoxin activation proteinases may be associated with resistance to Bt toxin in this resistant strain of O. nubilalis.
authors.affiliation: Department of Entomology, Kansas State University, Manhattan 66506, USA.
authors.forename: Huarong
authors.initials: H
authors.lastname: Li
authors.forename: Brenda
authors.initials: B
authors.lastname: Oppert
authors.forename: Randall A
authors.initials: RA
authors.lastname: Higgins
authors.forename: Fangneng
authors.initials: F
authors.lastname: Huang
authors.forename: Kun Yan
authors.initials: KY
authors.lastname: Zhu
authors.forename: Lawrent L
authors.initials: LL
authors.lastname: Buschman
mesh_terms: D000626:Aminopeptidases / Q000378:metabolism; D000818:Animals; D001413:Bacillus thuringiensis / Q000378:metabolism / Q000502:physiology*; D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins / Q000378:metabolism; D001427:Bacterial Toxins / Q000378:metabolism; D002918:Chymotrypsin / Q000378:metabolism; D004064:Digestive System / Q000201:enzymology; D010450:Endopeptidases / Q000378:metabolism*; D004731:Endotoxins / Q000378:metabolism; D006460:Hemolysin Proteins; D007814:Larva / Q000201:enzymology / Q000382:microbiology; D007915:Lepidoptera / Q000201:enzymology* / Q000382:microbiology*; D010196:Pancreatic Elastase / Q000378:metabolism; D014357:Trypsin / Q000378:metabolism
chemical_list: D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins; D001427:Bacterial Toxins; D004731:Endotoxins; D006460:Hemolysin Proteins; C030956:insecticidal crystal protein, Bacillus Thuringiensis; D010450:Endopeptidases; D000626:Aminopeptidases; D002918:Chymotrypsin; D010196:Pancreatic Elastase; D014357:Trypsin