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Denise Gregory

Denise J. Gregory

Chemistry and Biochemistry

Assistant Professor

Degrees

  • B.S., Jackson State University
  • Ph.D., Georgia Institute of Technology

Biography

Dr. Gregory joined the faculty at Samford in 2004. Prior to coming to Samford, she held a post-doctoral research position with the United States Department of Agriculture (Catfish Genetics Research Unit) and was a faculty member at Tuskegee University.

Currently Dr. Gregory is working on a project with Dr. Lisa Nagy. Their research focuses on bioremediation of pharmaceutical drugs found in wastewater. Large amounts of pharmaceuticals make their way into the waste stream due to ingested or unused medications. These drugs often have serious effects on river ecosystems. Some of the major pharmaceutical contaminants of wastewater and biosolids include carbamazapine, diphenhydramine, ethinylestradiol and fluoxetine. Because of the similar functional groups present in lignin, lignolytic fungi maybe useful in degradation of these compounds.

Softwood Lignin Fragment

Lignin is a major component of plant cell walls. It is a complex polymer consisting of crosslinked phenylpropane units which contains large numbers of various types of ether linkages and free phenol groups.

Extensive studies of white-rot fungi have shown that three enzymes (manganese peroxidase, laccase, and lignin perioxidase) are responsible for the depolymerization of lignin. These enzymes are important as decay organisms, aiding in the breakdown of logs, leaves, stems and other organic debris. This is an important role of fungi resulting in the recycling of essential nutrients in the biosphere.

Ethinylestradiol and fluoxetine are two of the many pharmaceutical contaminents found in waste water. Both of these compounds have functional group structures are similar to those in lignin. Because of these similarities to each other we are proposing to investigate the degradation of ethinylestradiol and fluoxetine by a white-rot fungus.

Researchers have shown that white rot fungi are able to degrade bisphenol A (a raw material used in the chemical synthesis of industrial polymers). Different types of white rot fungi will be cultured and grown on agar plates. Optimal mycelium growth will be studied to determine the ideal conditions and determine if the fungi are resistance to either ethinylestradiol or fluoxetine. After full growth of the mycelium a predetermined amount of the pharmaceutical will be incubated in the sample. After predetermined intervals the residual nondegraded pharmaceutical will be extracted. Analysis of the degradation products will be performed using LC-MS and 1H-NMR. Initially determination of possibilities of the degradation products will be done using a MS library. Further investigation will be needed to confirm the products produced. 1H NMR analysis of the breakdown can be used in the determination of these products produced from the degradation process.

During her spare time Dr. Gregory enjoys spending time with her family; her husband, Shawn, her 5 year old daughter, Shawnise and her 19 year old step-son, Shawn.

Publications

  • Gregory, D.J.; Waldbieser, G.C.; Bosworth, B.G. Cloning and characterization of myogenic regulatory genes in three Ictalurid species. Animal Genetics 2004, 35, 425-430.
  • Henderson, P.T.; Jones (Gregory), D.; Hampikian, G.; Kan, Y.; Schuster, G. B. Long distance charge transport in duplex DNA: the phonon-assisted polaron-like hopping mechanims. Proc. Natl. Acad. Sci. U.S.A. 1999, 96, 8353-8358.

Contact Information

Howard College of Arts and Sciences

Chemistry and Biochemistry Department

Samford University
800 Lakeshore Drive
Birmingham, AL 35229

Office: PROPST 331

Phone: (205) 726-2725

Fax: (205) 726-2479