Luminal proteinases from Plodia interpunctella and the hydrolysis of Bacillus thuringiensis CryIA(c) protoxin.
The ability of proteinases in gut extracts of the Indianmeal moth, Plodia interpunctella, to hydrolyze Bacillus thuringiensis (Bt) protoxin, casein, and rho-nitroanilide substrates was investigated. A polyclonal antiserum to protoxin CryIA(c) was used in Western blots to demonstrate slower protoxin processing by gut enzymes from Bt subspecies entomocidus-resistant larvae than enzymes from susceptible or kurstaki-resistant strains. Enzymes from all three strains hydrolyzed N-alpha-benzoyl-L-arginine rho-nitroanilide, N-succinyl-ala-ala-pro-phenylalanine rho-nitroanilide, and N-succinyl-ala-ala-pro-leucine rho-nitroanilide. Zymograms and activity blots were used to estimate the apparent molecular masses, number of enzymes, and relative activities in each strain. Several serine proteinase inhibitors reduced gut enzyme activities, with two soybean trypsin inhibitors, two potato inhibitors, and chymostatin the most effective in preventing protoxin hydrolysis.
Oppert
B
B
U.S. Grain Marketing Research Laboratory, ARS-USDA, Manhattan, KS 66502-2736, USA. bso@ksu.ksu.edu
Kramer
K J
KJ
Johnson
D
D
Upton
S J
SJ
Mcgaughey
W H
WH
D000818:Animals; D001413:Bacillus thuringiensis / Q000378:metabolism*; D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins / Q000378:metabolism*; D001427:Bacterial Toxins / Q000378:metabolism*; D004064:Digestive System / Q000201:enzymology; D010450:Endopeptidases / Q000378:metabolism*; D004731:Endotoxins / Q000378:metabolism*; D006460:Hemolysin Proteins; D006868:Hydrolysis; D009036:Moths / Q000201:enzymology*; D011480:Protease Inhibitors / Q000494:pharmacology; D013379:Substrate Specificity
D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins; D001427:Bacterial Toxins; D004731:Endotoxins; D006460:Hemolysin Proteins; D011480:Protease Inhibitors; C030956:insecticidal crystal protein, Bacillus Thuringiensis; D010450:Endopeptidases