Final Report: Biological Effects of Epoxy Fatty Acids

EPA Grant Number: R829479C011
Subproject: this is subproject number 011 , established and managed by the Center Director under grant R829479
(EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).

Center: The Consortium for Plant Biotechnology Research, Inc., Environmental Research and Technology Transfer Program
Center Director: Schumacher, Dorin
Title: Biological Effects of Epoxy Fatty Acids
Investigators: Sedlacek, John D.
Institution: Kentucky State University
EPA Project Officer: Lasat, Mitch
Project Period: January 1, 2003 through December 31, 2004
RFA: The Consortium for Plant Biotechnology Research, Inc., Environmental Research and Technology Transfer Program (2001) RFA Text |  Recipients Lists
Research Category: Targeted Research , Hazardous Waste/Remediation

Objective:

This is a follow-on project to R829479C003. Stored-grain insect pests have traditionally been controlled with synthetic chemical insecticides or fumigants. Mounting public concern, however, over pesticide residues in food, increasing numbers of stored-grain and vegetable insect pest species exhibiting insecticide resistance, loss of methyl bromide, restrictions on phosphine, and most recently the Food Quality Protection Act of 1996, make it necessary to investigate novel management strategies including natural products.

Several plants are known that naturally accumulate epoxy fatty acids in their seed oil. It is thought that plants have evolved this characteristic as a chemical defense. The impact, however, of such compounds on seed pests is not known. Also, there is interest in producing various epoxy fatty acids in bioreactors or engineered plants for multiple industrial uses. Some of these compounds might be useful new antibiotic compounds and the toxicological properties of those used for industrial purposes should be better understood. A considerable market currently exists for epoxy fatty acids, particularly for resins, epoxy coatings, and plasticizers. The current United States plasticizer market is approximately 2 billion pounds per year. Presently, most of this is derived from petroleum. In addition, there is industrial interest in the use of epoxy fatty acids in oil-based paints, lubricants and lubricant additives, adhesives, insecticides and insect repellants, crop oil concentrates, and the formulation of carriers for slow-release pesticides and herbicides.

Although it has been widely hypothesized that there is evolutionary pressure for organisms to synthesize epoxy fatty acids as a chemical defense, the defensive properties of these compounds are largely unknown.

The objective of this research project was to examine bioactivity of epoxy fatty acids on maize weevil, red flour beetle, sawtoothed grain beetle, and flour mill beetle.

The specific objectives were to: (1) isolate epoxy fatty acids from suitable natural sources that are models for oilseed improvement such as Vernonia seeds; (2) produce other epoxy fatty acids using in vitro enzymes, microorganisms, and engineered plant tissues; (3) test the effects of these epoxy fatty acids on stored product insect pests and model bacteria; and (4) test the effects of these epoxy fatty acids on stored product insect pest behavior.

Dr. David Hildebrand’s laboratory at the University of Kentucky primarily was responsible for carrying out the research for objectives 1 and 2 and the bacterial component of objective 3, as well as some epoxy fatty acid biosynthesis studies. Dr. John Sedlacek’s laboratory at Kentucky State University was responsible for the bioassays on storage insect pests in objective 3, as well as objective 4.

We conducted replicated bioassays exposing maize weevil, sawtoothed grain beetle, red flour beetle, and flour mill beetle to three epoxy fatty acids extracted from iron weed, Vernonia galamensis, and two epoxy fatty acids derived from castor beans, Ricinis communis. Specifically, we quantified adult mortality and progeny production of these four stored grain beetle species at a dose of 30 times 103 ppm of vernonia oil, vernolate, vernolic acid, castor oil, and hydrolyzed castor oil. This dose is similar to the amount found in V. galamensis seeds.

Summary/Accomplishments (Outputs/Outcomes):

Mortality

Maize weevils exposed to corn kernels individually treated with the epoxy fatty acids exhibited significant mortality. Mortality was highest, however, for the maize weevils exposed to the kernels treated with vernonia oil (P < 0.0001). Methyl vernolate and vernonia oil caused the highest mortality for flour mill beetle adults (P < 0.0001). Significant mortality was not seen for red flour beetle or sawtoothed grain beetle.

Progeny Production

Each of the beetle species exposed to the vernonia oil, methyl vernolate, or vernolic acid had significantly lower progeny emergence. Maize weevil progeny emergence was 99 percent, 92 percent, and 94 percent lower on kernels treated with vernonia oil, methyl vernolate, and vernolic acid, respectively. Reduction of red flour beetle emergence was not as high for these compounds but was highest (88%) for individuals exposed to methyl vernolate. Similarly, reduction of sawtoothed grain beetle progeny emergence ranged from 57 percent to 82 percent on these three compounds. Reduction of flour mill beetle progeny emergence was greater than 98 percent for vernonia oil, methyl vernolate, and vernolic acid.

Behavior

When compared against the control, average means suggest that vernonia oil acted as a repellent to maize weevil, red flour beetle, and sawtoothed grain beetle. It appears that vernolic acid acted as an attractant to all three species. Statistical analyses still need to be performed. Results using methyl vernolate, castor oil, and hydrolyzed castor oil were not consistent among the three species.

Conclusions:

Mortality was statistically significant for maize weevil exposed to vernonia oil, vernolic acid, castor oil, and hydrolyzed castor oil. Mortality of adult flour mill beetle was only statistically significant for vernonia oil and methyl vernolate. Except for maize weevil mortality on vernonia oil, these differences did not seem to be biologically significant because percentages of kill were low.

Reduced maize weevil emergence on vernonia oil treated kernels was not surprising because mortality was high. Significantly lower progeny emergence of maize weevil on the other treated kernels and for red flour beetle, sawtoothed grain beetle, and flour mill beetle on vernonia oil, methyl vernolate, and vernolic acid was of interest because mortality of adults was not significant. The question then becomes: are eggs laid and larvae dying or are adults being repelled and eggs not being laid.

Based on the progeny emergence analyses and the preliminary behavioral bioassays, it seems that the crude vernonia oil acts as a repellent. Pigments (antioxidants) in the crude oil could be responsible for this phenomenon. The pigmentless vernolic acid could have some insecticidal properties for larval insects.

Journal Articles:

No journal articles submitted with this report: View all 4 publications for this subproject

Supplemental Keywords:

sustainable industry, waste, agricultural engineering, bioremediation, environmental engineering, new technology, innovative technology, bioaccumulation, biodegradation, bioenergy, bioengineering, biotechnology, phytoremediation, plant biotechnology, epoxy fatty acids, stored grain insect pests, maize weevil, sawtoothed grain beetle, red flour beetle, flour mill beetle,, Scientific Discipline, TREATMENT/CONTROL, Sustainable Industry/Business, Geochemistry, Technology, New/Innovative technologies, Environmental Engineering, Agricultural Engineering, agrobacterium, genetics, bioengineering, epoxy fatty acids, in vitro enzymes, engineered plant tissues, oilseed improvement, plant genes, biotechnology, remediation, engineered plant tisues, bacteriacides, biological effects

Relevant Websites:

http://www.cpbr.org Exit

Progress and Final Reports:

Original Abstract
  • 2003 Progress Report

  • Main Center Abstract and Reports:

    R829479    The Consortium for Plant Biotechnology Research, Inc., Environmental Research and Technology Transfer Program

    Subprojects under this Center: (EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).
    R829479C001 Plant Genes and Agrobacterium T-DNA Integration
    R829479C002 Designing Promoters for Precision Targeting of Gene Expression
    R829479C003 aka R829479C011 Biological Effects of Epoxy Fatty Acids
    R829479C004 Negative Sense Viral Vectors for Improved Expression of Foreign Genes in Insects and Plants
    R829479C005 Development of Novel Plastics From Agricultural Oils
    R829479C006 Conversion of Paper Sludge to Ethanol
    R829479C007 Enhanced Production of Biodegradable Plastics in Plants
    R829479C008 Engineering Design of Stable Immobilized Enzymes for the Hydrolysis and Transesterification of Triglycerides
    R829479C009 Discovery and Evaluation of SNP Variation in Resistance-Gene Analogs and Other Candidate Genes in Cotton
    R829479C010 Woody Biomass Crops for Bioremediating Hydrocarbons and Metals
    R829479C011 Biological Effects of Epoxy Fatty Acids
    R829479C012 High Strength Degradable Plastics From Starch and Poly(lactic acid)
    R829479C013 Development of Herbicide-Tolerant Energy and Biomass Crops
    R829479C014 Identification of Receptors of Bacillus Thuringiensis Toxins in Midguts of the European Corn Borer
    R829479C015 Coordinated Expression of Multiple Anti-Pest Proteins
    R829479C016 A Novel Fermentation Process for Butyric Acid and Butanol Production from Plant Biomass
    R829479C017 Molecular Improvement of an Environmentally Friendly Turfgrass
    R829479C018 Woody Biomass Crops for Bioremediating Hydrocarbons and Metals. II.
    R829479C019 Transgenic Plants for Bioremediation of Atrazine and Related Herbicides
    R829479C020 Root Exudate Biostimulation for Polyaromatic Hydrocarbon Phytoremediation
    R829479C021 Phytoremediation of Heavy Metal Contamination by Metallohistins, a New Class of Plant Metal-Binding Proteins
    R829479C022 Development of Herbicide-Tolerant Energy and Biomass Crops
    R829479C023 A Novel Fermentation Process for Butyric Acid and Butanol Production from Plant Biomass
    R829479C024 Development of Vectors for the Stoichiometric Accumulation of Multiple Proteins in Transgenic Crops
    R829479C025 Chemical Induction of Disease Resistance in Trees
    R829479C026 Development of Herbicide-Tolerant Hardwoods
    R829479C027 Environmentally Superior Soybean Genome Development
    R829479C028 Development of Efficient Methods for the Genetic Transformation of Willow and Cottonwood for Increased Remediation of Pollutants
    R829479C029 Development of Tightly Regulated Ecdysone Receptor-Based Gene Switches for Use in Agriculture
    R829479C030 Engineered Plant Virus Proteins for Biotechnology