Educational / Professional Background
Dr. Oppert received B.S. and M.S. degrees in biology from the University
of Texas at El Paso. She received a Ph.D. in the area of protein
biochemistry from Kansas State University in 1991. Since that time,
Dr. Oppert has worked at GMPRC in the area of insect gut biochemistry.
Research Interests
Our research mission is to find better, safer ways to control insect pests found in and around food storage areas, including grain storage and processing facilities and warehouses. Often these pests are even smaller than field pests and provide challenges when trying to understand basic digestive processes and physiological responses. Therefore, we have adopted a number of proteomics and genomics techniques, including 2-D gel analysis, multiphase chromatography, protein identification by sequencing, peptide fingerprinting and mass spec, subgenome characterization, and gene expression. Specific research areas include the use of proteomics and genomics to understand insect responses to digestive proteinase inhibitors and microbial toxins. Comparisons of differential responses in insects have been particularly enlightening. This research will lead to improved control methods for stored product pests.
Current Projects
Discovery of more effective insect control proteins. Proteins
that negatively impact insect growth and development are useful
in insect control, because genes encoding insecticidal proteins
can be expressed in plants to enhance host plant resistance. Proteinase
inhibitors are good candidates because they disrupt insect digestion.
However, insects can compensate for proteinase inhibitors by increasing
the expression of digestive proteinases and/or expressing inhibitor-insensitive
proteinases. Dr. Oppert was part of a team that discovered that
combinations of digestive inhibitors targeting different proteinase
classes provided better control of some stored product pests. Testing
of other proteins by the research group led to the identification
of vitamin-binding proteins that were also effective in the control
of some stored product pests. Genes for these proteins can be expressed
in wheat, maize, and other cereals to reduce pest damage to these
products.
Biochemical techniques developed to evaluate proteinases in
mixtures. Insect proteinases are being investigated to identify
those that may be targeted by biopesticides. The study of stored
product insect proteinases is complicated by the small size of the
insect, and the collection of sufficient quantities of digestive
proteinases for purification is problematic. Dr. Oppert developed
two major techniques that facilitate the analysis of complex mixtures
of proteinases. One technique is a fast, simple, and economical
microplate assay (see Oppert et al., 1997b). The other technique
provides both a qualitative and quantitative identification of proteinases
in the mixture (see Oppert and Kramer, 1998). These techniques have
promoted rapid and efficient identification of digestive proteinases
in moth and beetle pests of stored products. Researchers from areas
other than agriculture have used these assays to study proteinases
prior to purification.
Elucidation of insect resistance to Bacillus thuringiensis.
Proteinaceous toxins from the bacterium Bacillus thuringiensis
(Bt) have been used for years in spray applications to control insect
pests. Genes encoding these toxins are now being expressed in plants
to control crop pests. Expression of Bt toxins in plants will increase
exposure levels to insects for longer periods, thus providing increased
selection pressure for the survival of resistant populations of
pests. Insects can adapt to Bt toxins through an alteration in the
gut receptor that binds the toxin in the early stages of toxicity.
Through her work with digestive proteinases of the Indianmeal moth,
a major pest of stored products, Dr. Oppert described a novel mechanism
of insect resistance to Bt. Some Bt-resistant Indianmeal moths have
reduced digestive proteinase activity that enables them to survive
on diets containing Bt toxins. This was the first evidence of multiple
adaptations in insects that result in a loss of Bt toxin efficacy.
Information from this research is being used in the design of more
efficient microbial toxins and in the development of effective resistance
management policies.
Project Information
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Proteolytic Enzyme Activity of Kentucky and Kansas Bacillus thuringiensis Susceptible and Resistant Indianmeal Moths Reared on Transgenic Bt Corn
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Bacillus thuringiensis (Bt) transformed plants are effective for controlling many insect pests, but insect resistance threatens the long term effectiveness of these toxins. Proteinase-mediated mechanisms may be involved in resistance to Bt and are investigated in this experiment.
Poster
Agricultural Research Service (ARS) News
- Magazine Articles
- Avidin: An Egg-Citing Insecticidal Protein in Corn
- News, Miscellaneous
- Missing Enzyme Linked to Bt-Resistance in Insects
Recent Publications
To list all publications * and request reprints for which no PDF file is available, click here *. |
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Goiptar, I.A., I.Y. Filippova, E.N. Lysogorskaya, E.S. Oksenoit, K.S. Vinokurov, D.P. Zhuzhikov, N.V. Bulushova, I.A. Zalunin, Y.E. Dunaevsky, M.A. Belozersky, B. Oppert, and E.N. Elpidina. 2008. Localization of post-proline cleaving peptidases in Tenebrio molitor larval midgut. Biochimie 90: 508-514.
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Janarthanan, S., P. Suresh, G. Radke, T.D. Morgan, and B. Oppert. 2008. Arcelins from an Indian wild pulse, Lablab purpureus, and insecticidal activity in storage pests. J. Agric. Food Chem. 56: 1676-1682.
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Park, Y., J. Aikins, L.J. Wang, R.W. Beeman, B. Oppert, J.C. Lord, S.J. Brown, M.D. Lorenzen, S. Richards, G.M. Weinstock, and R.A. Gibbs. 2008. Analysis of transcriptome data in the red flour beetle, Tribolium castaneum. Insect Biochem. Mol. Biol. 38: 380-386.
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Tamez-Guerra, P., J.A. Valadez-Lira, J.M. Alcocer-Gonzalez, B. Oppert, R. Gomez-Flores, R. Tamez-Guerra, and C. Rodriguez-Padilla. 2008. Detection of genes encoding antimicrobial peptides in Mexican strains of Trichoplusia ni (Hubner) exposed to Bacillus thuringiensis. J. Invertebr. Pathol. 98: 218-227.
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Tribolium Sequencing Consortium (includes R.W. Beeman, M.D. Lorenzen, B. Oppert, J. Lord, K. Kramer, Y. Arakane). 2008. The genome of the model beetle and pest Tribolium castaneum. Nature 452: 949-955.
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Karumbaiah, L., B. Oppert, J.L. Jurat-Fuentes, and M.J. Adang. 2007. Analysis of midgut proteinases from Bacillus thuringiensis-susceptible and -resistant Heliothis virescens (Lepidoptera: Noctuidae). Comp. Biochem. Physiol. Part B 146: 139-146.
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Li, H., L.L. Buschman, F. Huang, K.Y. Zhu, B. Bonning, and B. Oppert. 2007. DiPel-selected Ostrinia nubilalis larvae are not resistant to transgenic corn expressing Bacillus thuringiensis Cry1Ab. J. Econ. Entomol. 100: 1862-1870.
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Li, H., L.L. Buschman, K.Y. Zhu, F. Huang, and B. Oppert. 2007. Resistance to Bacillus thuringiensis endotoxins in the European corn borer, Ostrinia nubilalis. Biopestic. Int. 3: 96-107.
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Prabhakar, S., M.S. Chen, E.N. Elpidina, K.S. Vinokurov, C.M. Smith, J. Marshall, and B. Oppert. 2007. Sequence analysis and molecular characterization of larval midgut cDNA transcripts encoding peptidases from the yellow mealworm, Tenebrio molitor L. Insect Mol. Biol. 16: 455-468.
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Oppert, B. 2006. Two-dimensional analysis of proteinase activity. J. Biochem. Biophys. Methods 67: 173-179.
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Oppert, B., P. Walters, and M. Zuercher. 2006. Digestive proteinases of the larger black flour beetle, Cynaeus angustus (Coleoptera: Tenebrionidae). Bull. Entomol. Res. 96: 167-172.
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Tamez-Guerra, P.G. Damas, M.M. Iracheta, B. Oppert, R. Gomez-Flores, and C. Rodriguez-Padilla. 2006. Differences in susceptibility and physiological fitness of Mexican field Trichoplusia ni strains exposed to Bacillus thuringiensis. J. Econ. Entomol. 99: 937-945.
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Vinokurov, K.S., E.N. Elpidina, B. Oppert, S. Prabhakar, D.P. Zhuzhikov, Y.E. Dunaevsky, and M.A. Belozersky. 2006. Fractionation of digestive proteinases from Tenebrio molitor (Coleoptera: Tenebrionidae) larvae and role in protein digestion. Comp. Biochem. Physiol. Part B 145: 138-146.
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Vinokuroz, K.S., E.N. Elpidina, B. Oppert, S. Prabhakar, D.P. Zhuzhikov, Y.E. Dunaevsky, and M.A. Belozersky. 2006. Diversity of digestive proteinases in Tenebrio molitor (Coleoptera: Tenebrionidae) larvae. Comp. Biochem. Physiol. Part B 145: 126-137.
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Elpidina, E.N., T.A. Tsybina, Y.E. Dunaevsky, M.A. Belozersky, D.P. Zhuzhikov, and B. Oppert. 2005. A chymotrypsin-like proteinase from the midgut of Tenebrio molitor larvae. Biochimie 87: 771-779.
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Li, H., B. Oppert, R.A. Higgins, F. Huang, L.L. Buschman, and K.Y. Zhu. 2005. Susceptibility of Dipel-resistant and -susceptible Ostrinia nubilalis (Lepidoptera: Crambidae) to individual Bacillus thuringiensis protoxins. J. Econ. Entomol. 98: 1333-1340.
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Li, H., B. Oppert, R.A. Higgins, F. Huang, L.L. Buschman, J. Gao, and K.Y. Zhu. 2005. Characterization of cDNAs encoding three trypsin-like proteinases and mRNA quantitative analysis in Bt-resistant and -susceptible strains of Ostrinia nubilalis. Insect Biochem. Mol. Biol. 35: 847-860.
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Oppert, B., T.D. Morgan, K. Hartzer, and K.J. Kramer. 2005. Compensatory proteolytic responses to dietary proteinase inhibitors in the red flour beetle, Tribolium castaneum (Coleoptera: Tenebrionidae). Comp. Biochem. Physiol. Part C 140: 53-58.
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Tsybina, T.A., Y.E. Dunaevsky, M.A. Belozersky, D.P. Zhuzhikov, B. Oppert, and E.N. Elpidina. 2005. Digestive proteinases of yellow mealworm (Tenebrio molitor) larvae: purification and characterization of a trypsin-like proteinase. Biochemistry (Moscow) 70: 300-305.
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Vinokurov, K.S., B. Oppert, and E.N. Elpidina. 2005. An overlay technique for postelectrophoretic analysis of proteinase spectra in complex mixtures using p-nitroanilide substrates. Analyt. Biochem. 337: 164-166.
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Zhu, Y.C., X. Liu, A.S. Maddur, B. Oppert, and M.S Chen. 2005. Cloning and characterization of chymotrypsin- and trypsin-like cDNAs from the gut of the Hessian fly [Mayetiola destructor (say)]. Insect Biochem. Mol. Biol. 35: 23-32.
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Li, H., B. Oppert, R.A. Higgins, F. Huang, K.Y. Zhu, and L.L. Buschman. 2004. Comparative analysis of proteinase activities of Bacillus thuringiensis-resistant and -susceptible Ostrinia nubilalis (Lepidoptera: Crambidae). Insect Biochem. Mol. Biol. 34: 753-762.
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Li, H., J. González-Cabrera, B. Oppert, J. Ferré, R.A. Higgins, L.L. Buschman, G.A. Radke, K.Y. Zhu, and F. Huang. 2004. Binding analyses of Cry1Ab and Cry1Ac with membrane vesicles from Bacillus thuringiensis-resistant and -susceptible Ostrinia nubilalis. Biochem. Biophys. Res. Comm. 323: 52-57.
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Candas, M., O. Loseva, B. Oppert, P. Kosaraju, and L.A. Bulla, Jr. 2003. Insect resistance to Bacillus thuringiensis: Alterations in the Indianmeal moth larval gut proteome. Mol. Cell. Proteomics 2: 19-28.
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Li, H., B. Oppert, K.Y. Zhu, R.A. Higgins, F. Huang, and L.L. Buschman. 2003. Transgenic plants expressing Bacillus thuringiensis delta-endotoxins. Entomologia Sinica 10: 155-166.
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Oppert, B., T.D. Morgan, K. Hartzer, B. Lenarcic, K. Galesa, J. Brzin, V. Turk, K. Yoza, K. Ohtsubo, and K.J. Kramer. 2003. Effects of proteinase inhibitors on digestive proteinases and growth of the red flour beetle, Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae). Comp. Biochem. Physiol. Part C 134: 481-490.
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Zhu, Y.C., F. Zeng, and B. Oppert. 2003. Molecular cloning of trypsin-like cDNAs and comparison of proteinase activities in the salivary glands and gut of the tarnished plant bug Lygus lineolaris
(Heteroptera: Miridae). Insect Biochem. Mol. Biol. 33: 889-899.
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Oppert, B., K. Hartzer, and M. Zuercher. 2002. Digestive proteinases in Lasioderma serricorne (Coleoptera: Anobiidae). Bull. Entomol. Res. 92: 331-336.
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Herrero, S., B. Oppert, and J. Ferre. 2001. Different mechanisms of resistance to Bacillus thuringiensis toxins in the Indianmeal moth. Appl. Environ. Microbiol. 67: 1085-1089.
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Oppert, B., K. Hartzer, and C.M. Smith. 2000. Digestive proteinases of alfalfa weevil, Hypera postica, (Gyllenhal) (Coleoptera: Curculionidae). Trans. Kansas Acad. Sci. 103: 99-110.
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