Adam J. Kuhl
Gulf Coast Research Laboratory
Department of Coastal Sciences
703 East Beach Drive (39564)
P. O. Box 7000
Ocean Springs, MS 39566-7000
Graduate Student Research Assistant
Department of Coastal Sciences,
Environmental Biochemistry and Toxicology
University of Southern Mississippi
Gulf Coast Research Laboratory)
Ph.D. Coastal Sciences (expected graduation Dec. 2004)
Advisor: Dr. Marius Brouwer
Project: The effects of endocrine disrupting chemicals on sex
differentiation in Japanese medaka (Oryzias latipes) and the role of brain aromatase
Degree: B.S January 1998
Major: Animal Science
My research interests are in environmental toxicology with an emphasis on reproduction and development. In my Ph.D. research I am focusing on the impact of endocrine disruptors on sexual determination and development of medaka. In fish estrogen is required for the development of primary and secondary sex characteristics of female fish and is provided by the aromatization of androgens by aromatase. There are two isoforms of aromatase in several teleost species, brain and ovarian. The objective of my research is twofold: clone and sequence the coding and promoter region of brain aromatase in medaka, and determine the effects of exposure to endocrine disrupting compounds (o,p-DDT, tributyltin, aromatase inhibitor) on sex determination and brain aromatase transcription and activity.
The brain aromatase coding sequence was obtained by Reverse Transcription Polymerase Chain Reaction (RT-PCR) and PCR-based genomic DNA walking was used to clone the promoter of the brain aromatase gene. Brain aromatase promoter sequence analysis reveals potential binding sites for transcription factors involved in primary neurogenesis, the estrogen receptor, and factors known to be involved in sex determination. The presence these factors in the promoter of brain aromatase implies a convergence of the sex-determination pathway and neurogenesis pathway in medaka central nervous system.
Medaka fry were subjected to an aqueous exposure of o,p-DDT, tributyltin (TBT), fadrozole (an aromatase inhibitor) and cotreatments of o,p-DDT / fadrozole and TBT / fadrozole. Brain aromatase expression was measured through real-time PCR and aromatase activity was measured using a tritiated water release assay. Results analyzed from DDT exposure suggest that brain aromatase is involved in the abnormal sexual differentiation of fish treated with xenoestrogens. Fadrozole and TBT results are currently being analyzed.
Other research includes developing a simple rapid screening assay for endocrine disrupting compounds using red/white medaka. Sediment from areas of suspected endocrine disrupting contamination from coastal Mississippi was collected and exposed to medaka fry. Using a strain of medaka with a Y-linked phenotypic color marker, it is possible to determine if a fish has undergone sex-inversion by examining the phenotypic color and secondary sexual characteristics. Fish that have undergone male to female sex-inversion will have a male color (due to the presence of the Y chromosome) and yet have female secondary sex characteristics. This research is ongoing.
Laboratory skills: RT-PCR, Real-time quantitative-PCR, promoter cloning and sequence analysis, HPLC (fluorescence and photodiode array), Enzyme Immuno Assays, protein extraction and enzyme activity assay (with radioisotopes), animal exposures and exposure systems, fish culture systems (freshwater and marine), ARC GIS
Field work: Boat use and repair, sample collection (animal, sediment, water) <o:p></o:p>
Research Assistant. University of Southern Mississippi, Ocean Springs, MS. 1/2002 ? date. Maintained toxicology research facility containing culture and exposure facilities for freshwater and marine fish and invertebrates. Assistance with field work in the EPA?s Gulf of Mexico Estuarine and Great Lakes (EaGLe) Environmental Indicators Program.
National Coastal Assessment 2002 Field Technician. University of Southern Mississippi, Ocean Springs, MS. 7/2002-8/2002. Collected water, sediment, and fish samples at fifty sites throughout Mississippi coast for extensive multi-year national coastal assessment program of EPA.
Teaching Assistant. University of Southern Mississippi, Hattiesburg, MS. 9/1999 - 12/2001. Taught 2 classes per semester of freshman biology laboratory. Maintained office hours for one-on-one tutoring.
Research Technician. Rockefeller University, New York City, NY. 6/1998 ? 8/1999. Maintained 25,000 fish zebrafish facility for mutagenesis study involving otolith development. Responsible for culture and system maintenance and organization and perpetuation of various zebrafish strains.
Undergraduate Research Assistant. Cornell University, Ithaca, NY. 5/1998 ? 12/1998. Performed research project involving hydrogen peroxide tolerance in walleye fry. Consisted of summer internship at Cornell Biological Field Station and continued with assistantship at the Department of Microbiology and Immunology, Cornell University College of Vetrinary Medicine.
Society of Environmental Toxicology and Chemistry (SETAC) 2002 - present.
Pollutant Response in Marine Organisms 12 (PRIMO 12) Student travel award
2002 SETAC Salt Lake City, UT. Cloning and Sequencing of Brain Aromatase and Phenotypic Sex Response to Exogenous Estrogens in Japanese Medaka (Oryzias latipes)
2003 PRIMO 12. Tampa, FL. (Interactive Poster). Medaka brain aromatase and its response to the xenoestrogen o,p-DDT
2003 SETAC Austin, TX. Brain Aromatase and its Response to o,p?DDT in Japanese Medaka
2004 SETAC World Congress (Platform). Portland, OR. Effects of Endocrine Disrupting Chemicals on Sex Differentiation in Medaka and the Role of Brain Aromatase
Tort, M.J., Kuhl, A.J., Wooster, G.A., Bowser, P.R. 1998. Modification of walleyes (Stizostedion vitreum) tolerance to hydrogen peroxide bath treatment. Journal of the World Aquaculture Society. 29(4) 499-504.
Kuhl, A.J., Brouwer, M. 2003. Oryzias latipes brain aromatase (CYP19B)
mRNA, complete cds. Genbank accession # AY319970.
Kuhl, A.J., Manning, C.S., Brouwer, M. 2004. Brain Aromatase in Japanese
Medaka (Oryzias latipes): Molecular characterization and role in xenoestrogen induced sex reversal. Journal of Steroid Biochemistry and Molecular Biology. (Submitted).