Page Banner

United States Department of Agriculture

Agricultural Research Service

Title: Effects of Proteinase Inhibitors on Growth and Digestive Proteolysis of the Ref Flour Beetle, Tribolium Castaneum (Herbst) (Coleoptera: Tenebrionidae)

Authors
item Oppert, Brenda
item Morgan, Thomas
item Hartzer, Kris - KANSAS STATE UNIVERSITY
item Lenarcic, B - J STEFAN INST, SLOVENIA
item Galesa, K - J STEFAN INST, SLOVENIA
item Brzin, J - J STEFAN INST, SLOVENIA
item Turk, Vito - J STEFAN INST, SLOVENIA
item Yoza, K - NATL FOOD RES INST,JAPAN
item Ohtsubo, K - NATL FOOD RES INST, JAPAN
item Kramer, Karl

Submitted to: Journal of Insect Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: February 24, 2003
Publication Date: May 23, 2003
Citation: OPPERT,B.S., MORGAN,T.D., HARTZER,K., LENARCIC,B., GALESA,K., BRZIN,J., TURK,V., YOZA,K., OHTSUBO,K., KRAMER,K.J., EFFECTS OF PROTEINASE INHIBITORS ON GROWTH AND DIGESTIVE PROTEOLYSIS OF THE REF FLOUR BEETLE, TRIBOLIUM CASTANEUM (HERBST) (COLEOPTERA: TENEBRIONIDAE). COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY PART C 134 (2003) 481-490.

Interpretive Summary: The red flour beetle is a major pest of stored grains and grain products worldwide. Our previous research suggested that inhibitors of digestive enzymes, in the right combination, could be effective in controlling this beetle pest. We tested a number of protein inhibitors alone and in combination to identify those that reduced the growth of red flour beetle larvae. Although several demonstrated potency, inhibitors from potato and soybean had the greatest potential for red flour beetle control. Combining genes encoding the potato inhibitor and a soybean inhibitor in transgenic cereals may help to prevent damage to grains by storage pests.

Technical Abstract: Several proteinase inhibitors were tested in vivo with larvae of the red flour beetle, Tribolium castaneum, and in vitro with larval gut extracts to identify inhibitors with potential for use as biopesticides in transgenic plants. In vivo, the most effective inhibitor for suppressing larval growth was L-trans-epoxysuccinylleucylamide [4-guanidino] butane (E-64), followed by cysteine proteinase inhibitors from potato (PCPI), Job's tears (JCPI), and a sea anemone (equistatin). The combination of 0.1% E-64 and 1% soybean trypsin inhibitor (Kunitz) (STI)resulted in the most significant growth suppression (87% weight reduction). Maximum hydrolysis of casein by extracts of larval gut proteinases occurred at pH 4.2. T. castaneum proteinases hydrolyzed the trypsin substrate N-a-benzoyl-DL-arginine-p- nitroanilide at both acidic and alkaline pH values. With the chymotrypsin substrate N-succinyl-Ala-Ala-Pro-Phe p-nitroanilide, however, hydrolysis by yT. castaneum proteinases was greatest at alkaline pH. In vitro, additional inhibitors were tested for their ability to inhibit casein hydrolysis by larval gut proteinases. The most effective inhibitors were leupeptin and E- 64, followed by equistatin, tosyl-L-lysine chloromethyl ketone, JCPI, PCPI, and antipain. Chymostatin, N-tosyl-L-phenylalanine chloromethyl ketone, and STI only weakly inhibited T. castaneum digestive proteinases. These data indicate that cysteine proteinases have a predominate role in digestion, with serine proteinases playing a lesser role in protein digestion.

Last Modified: 4/19/2014
Footer Content Back to Top of Page