Teaching and Research Interests
I obtained my Ph.D. in Biochemistry and Cell Biology at Rice University (Houston, Texas) in 2004 in a plant hormone genetics laboratory with Dr. Bonnie Bartel. My research interests focus on auxins, a class of phytohormones affecting virtually every aspect of plant development. Plants regulate auxin levels through complex interactions among de novo synthesis, degradation, influx, efflux, and conjugate synthesis and hydrolysis. A thorough knowledge of these pathways is key to understanding auxin influences on plants.
In a collaborative effort with Dr. Bethany Zolman, an Associate Professor of Biology at the University of Missouri in St. Louis, we are using genetic approaches to better understand the function of certain proteins involved in auxin storage and metabolism in the model plant Arabidopsis. A forward genetic screen identified a mutant defective in auxin-conjugate response, J56. We have used next-generation sequencing to compare mutant and genomic sequences and several mutations were identified in J56. Students are working to identify the causative mutation for the J56 auxin phenotype using several approaches, including isolating mutant alleles for candidate genes, using PCR to assay homozygous J56 lines for segregation of each mutation, and using quantitative PCR to measure expression levels of the candidate genes.
Our research also focuses on the interaction between auxin and other plant hormones, such as gibberellin. Students are analyzing a quadruple mutant defective in auxin storage pathways to determine if reduced auxin mutant phenotypes (such as delayed germination) occur due to altered gibberellin biosynthesis.
Students who enroll in BIOL 3710L, Molecular Genetics Laboratory, may be involved in a component of these research projects.
Links
Selected Publications:
Spiess, G.M., Hausman, A., Yu, P., Cohen, J.D., Rampey R.A., and Zolman, B.K. Auxin input pathway disruptions are mitigated by changes in auxin biosynthetic gene expression in Arabidopsis. Plant Physiology 165: 1092-1104, 2014.
Rampey, R.A., Baldridge, M.T., Farrow, D.C., Bay, S.N., and Bartel, B. Compensatory mutations in predicted metal transporters modulate auxin conjugate responsiveness in Arabidopsis. Genes Genomes Genetics 1: 131-141, 2013.
Strader, L.C., Wheeler, D.L., Christensen, S.E., Berens, J.C., Cohen, J.D., Rampey, R.A., and Bartel, B. Multiple facets of Arabidopsis seedling development require indole-3-butyric acid-derived auxin. Plant Cell 23: 984-999, 2011.
Rampey, R.A., Woodward, A.W., Hobbs, B.N., Tierney, M.P., Lahner, B., Salt, D.E. and Bartel, B. An Arabidopsis basic helix-loop-helix leucine zipper protein modulates metal homeostasis and auxin conjugate responsiveness. Genetics, 174:1841-57, 2006.
López-Bucio, J., Hernández-Abreu, E., Sánchez-Calderón, L., Pérez-Torres, A., Rampey, R.A., Bartel, B., and Herrera-Estrella, L. An auxin transport independent pathway is involved in phosphate stress-induced root architectural alterations in Arabidopsis: Identification of BIG as a mediator of auxin in pericycle cell activation. Plant Physiology 137: 681-691, 2005.
Rampey, R.A., LeClere, S., Kowalczyk, M., Ljung, K., Sandberg, G., and Bartel, B. A family of auxin-conjugate hydrolases that contribute to free indole-3-acetic acid levels during Arabidopsis germination. Plant Physiology 135: 978-988, 2004.
LeClere, S., Rampey, R.A., and Bartel, B. IAR4, a gene required for auxin conjugate sensitivity in Arabidopsis, encodes a pyruvate dehydrogenase E1a homolog. Plant Physiology 135: 989-999, 2004.
LeClere, S., Tellez R., Rampey R.A., Matsuda S.P.T., Bartel, B. Characterization of a family of IAA-amino acid conjugate hydrolases from Arabidopsis. Journal of Biological Chemistry. 23: 20446-52, 2002.
*Underlined authors indicate Harding undergraduate students.
Teaching and Research Interests:
I am interested in understanding how amphibians interact with their environment. The questions I ask are primarily ecological and frequently revolve around understanding how anthropogenic changes in the environment are affecting amphibians. Questions I have investigated include: How does hypoxia affect embryonic growth and development, and in turn, how does the embryo respond to hypoxia through changes in egg capsule oxygen conductance? How do pesticides interact with environmental variables, such as competition and predation, to alter the survival, growth, and timing of metamorphosis in amphibian larvae? And, how does artificial night lighting alter the behavior, spatial distribution, survival, and growth of amphibians? In addition to my primary research interests, I have had the privilege of collaborating with Mike Plummer (Professor emeritus) on research investigating the ecology of turtles and snakes. Most recently, I have begun planning for amphibian surveys at the Gilliam Biological Research Station (GBRS). In addition to gaining valuable information on the diversity and abundance of amphibians at the research station, I expect these surveys to raise interesting questions that will provide the basis for future research activities.
Over the years, I have taught or co-taught 16 different classes. My current teaching responsibilities include Ornithology, Herpetology, Ecology, Principles of Biology (majors), and Christian View of Science and Scripture.
Links
The Ecological Society of America
Partners in Amphibian and Reptile Conservation
Selected Publications:
Plummer, M.V. C.S. O’Neal*, S.M. Cooper, R. Stork, A.B. McKinney*, and N.E. Mills. In Preparation. Precipitation and predator pressure elicit dispersal of Mud Snakes (Farancia abacura) from an isolated wetland.
Mills, N.E. and F.E. Rowland. In Preparation. Artificial night lighting alter amphibian habitat use.
Mills, N.E. and Z.A. Ward*. 2015. Egg hypoxia decreases posthatching survival and delays metamorphosis in Ambystoma maculatum (spotted salamanders). Journal of Herpetology 49:616-620.
Plummer, M.V. and N.E. Mills. 2015. Growth and maturity of spiny softshell turtles (Apalone spinifera) in a small urban stream. Herpetological Conservation and Biology 10:688-694.
Plummer, M.V. and N.E. Mills. 2010. Body temperature variation in free-ranging hognose snakes (Heterodon platirhinos). Journal of Herpetology 44:471-474.
Plummer, M.V., T.N. Lee*, and N.E. Mills. 2008. Effect of a sand substrate on the growth and condition of Apalone mutica hatchlings. Journal of Herpetology 42:550-554.
Plummer, M.V., D.G. Krementz, L.A. Powell, and N.E. Mills. 2008. Effects of habitat disturbance on survival rates of softshell turtles (Apalone spinifera) in an urban stream. Journal of Herpetology 42:555-563.
Plummer, M.V., and N.E. Mills. 2008. Chapter 7. Structure of an urban population of softshell turtles (Apalone spinifera) before and after severe stream alteration. In J.C. Mitchell, R.E. Jung Brown, and B. Bartholomew (eds.) Urban Herpetology. Herpetological Conservation Vol. 3. Society for the Study of Amphibians and Reptiles. Salt Lake City, UT.
Vall*, J.H. and N.E. Mills. 2007. Intermittent hypoxia in eggs of Ambystoma maculatum: Embryonic development and egg capsule conductance. Journal of Experimental Biology 210:2430-2435.
Lee*, T.N., M.V. Plummer, and N.E. Mills. 2007. Use of posthatching yolk and external forage to maximize early growth in Apalone mutica hatchlings. Journal of Herpetology 41:492-500.
Plummer, M.V. and N.E. Mills. 2006. Heterodon platirhinos (Eastern Hognose Snake) road crossing behavior. Herpetological Review 37:352.
Plummer, M.V., T.L. Crabill, N.E. Mills, and S.L. Allen. 2005. Body temperatures of free-ranging softshell turtles (Apalone spinifera) in a small stream. Herpetological Review 36:371-375.
Mills, N.E. and R.D. Semlitsch. 2004. Competition and predation mediate the indirect effects of an insecticide on southern leopard frogs. Ecological Applications 14:1041-1054.
Mills, N.E., M.C. Barnhart, and R. Semlitsch. 2001. Effects of hypoxia on egg capsule conductance in Ambystoma (class Amphibia, order Caudata). Journal of Experimental Biology 204:3747-3753.
Relyea, R.A. and N.E. Mills. 2001. Predator-induced stress makes the pesticide carbaryl more deadly to gray treefrog tadpoles (Hyla versicolor). Proceeding of the National Academy of Science 98:2491-2496.
Plummer, M.V. and N.E. Mills. 2000. Spatial ecology and survivorship of resident and translocated hognose snakes (Heterodon platirhinos). Journal of Herpetology 34:565-575.
Mills, N.E. and M.C. Barnhart. 1999. Effects of hypoxia on embryonic development in two Ambystoma and two Rana species. Physiological and Biochemical Zoology 72:179-188.
Plummer, M.V., N.E. Mills, and S.L. Allen. 1997. Activity, habitat, and movement patterns of softshell turtles (Trionyx spiniferus) in a small stream. Chelonian Conservation and Biology 2:514-420.
Plummer, M.V. and N.E. Mills. 1996. Observations on trailing and mating behaviors in hognose snakes (Heterodon platirhinos). Journal of Herpetology 30:80-82.
*indicates undergraduate student
Teaching Interests:
My primary research and training is in Microbiology and Immunology. After graduating with a Master’s degree in Microbiology, I worked as a clinical microbiology specialist for 7 years. After receiving my Ph.D. at the University of Arkansas for Medical Sciences in Microbiology and Immunology, I worked as a postdoctoral fellow at St. Jude Children’s Research Hospital (SJCRH) in Memphis for over 3 years. At SJCRH, I worked in the Department of Immunology in macrophage biology. My work primarily concerned antigen processing and presentation of various macrophage subsets. Since my departure from there, my primary interest has been infectious disease mechanisms and the immune responses to them. Along that line, I investigated the role of RNA interference in replication of the vesicular stomatitis virus in the nematode, C. elegans.
I presently enjoy developing laboratory and lecture material that enhance student learning. Most of my courses involve a laboratory component where students gain hands-on experience or can be involved in laboratory research. My primary teaching duties include Microbiology, Immunology, Virology, and Bioinformatics and Cell Analysis Laboratory.
Selected Publications:
Wilkins C., Dishongh R., Moore S.C., Whitt M.A., Chow M., Machaca K. RNa interference is an antiviral defense mechanism in Caernorhabditis elegans. Nature (2005) 18;436(7053):1044-7.
Moore S.C., McCormack J.M., Armendariz E., Gatewood J., Walker W.S. Phenotypes and alloantigen-presenting activity of individual clones of microglia derived from the mouse brain. J Neuroimmunol. 1992 Dec; 41(2):203-14.
*Underlined author indicates Harding undergraduate student.
Teaching and Research Interests:
My interest in the world around me began as a child, when I grew up reading National Geographic. It seems that wherever I found myself, I was picking up some rock or insect, or watching the world around me awed by the variety of living things and their interactions with the world. This fascination remained with me through high school and led me to eventually begin my higher education at Harding University where I earned a Bachelor of Science degree in Biology. Following graduation , I enrolled in Stephen F. Austin State University in the Biology program where I worked towards a Masters of Science in Aquatic Biology. I have always been concerned with the effects of man on animal life and the environment. Eventually I enrolled in University of Arkansas for Medical Sciences where I received my Ph.D. in Interdisciplinary Toxicology.
My education and training have equipped me with insight, knowledge of methods, and tools that have allowed me to observe the creation to a degree I never thought possible. My interests center around how external factors in the environment affect an animals' responses to exogenous chemicals.
Many of my past professors inspired me to examine the world around me and to critically think. They planted the seeds in me that led me to aspire to teach. Now that I am in the classroom, I hope that through the courses I teach that I might help my students curiosity to grow and inspire them to delve deeper into the study of God's handiwork.
I am currently collaborating on several projects with other Faculty in the Department of Biology. For the last year I have been privileged to work with Dr. Mike Plummer at Harding’s Gilliam Biological Research Station, modeling home ranges of the red-bellied mudsnake (Farancia abacura) using radiotracking. We are currently beginning a work with green snakes (Opheodrys sp.). I am also using the wolf spider (Rabidosa rabida) as a model organism for several projects involving our students. Currently I am also involved with an interdepartmental work with Dr. Dennis Province of the Chemistry Department on a few projects involving students.
Ultimately, my primary goal in my research is to include our undergraduates in projects that will lead to them designing, conducting and reporting data in peer reviewed journals and/or at professional meetings.
Links
UAMS: Department of Pharmacology and Toxicology
Selected Publications:
Steven Cooper, John R. Latendresse, Daniel R. Doerge, Nathan C. Twaddle, Xin Fu and K. Barry Delclos. 2006. Dietary Modulation of p-Nonylphenol–Induced Polycystic Kidneys in Male Sprague-Dawley Rats. Toxicological Sciences 2006 91(2):631-642
Teaching and Research Interests:
I obtained my PhD in Quantitative Biology from the University of Texas at Arlington in 2011 looking at thermal ecology and habitat choice in the wolf spider Rabidosa rabida. Since then, I have focused my research on describing the behavior and ecology of this common and ecologically important and yet relatively unstudied spider. I perform most of my projects at the Gillam Biological Research Station where I emphasize student involvement in all of my research. Descriptive ecology is an excellent area for a first undergraduate research project. Through my work, students have the opportunity to start on relatively simple observational projects. In doing so, they learn to make broader applications for biological observations and learn how to participate in the scientific process. Students then have the opportunity to build on their research experience by working on more involved projects that can be presented at professional meetings and published in national journals. I have a long list of questions, ranging from simple observational projects to high level questions, that I am always looking for interested student researchers to participate in. I also enjoy when people from the local community bring arthropods questions, as community interactions are always fun and provide valuable opportunities to educate the public about the arthropod world.
My teaching responsibilities at Harding University include Human Anatomy and Physiology and Medical Entomology (I have taught Ecology, Environmental Science, General Biology, and Zoology when needed). I find that an emphasis on observation and making appropriate application is a basic skill needed in all areas of science and that working with students learning how to be future scientists or medical professionals is just as rewarding as describing new spider behaviors and gets fewer odd looks.
Selected Publications:
Campbell, P.M., R.J. Stork, and A.G. Hug. 2020. The common feeder cockroach Blaptica dubia shows increased transmission distance based on mode of acquisition of environmental bacteria. Journal of the Arkansas Academy of Science 74 (2020): 21-25.
Hogland, B., R. Stork, and A. Hug. 2017. A description of variation in fecundity between two populations of the wolf spider Rabidosa rabida in Searcy Arkansas using brood size measurements. Proceedings of the Arkansas Academy of Science. 71(1): 47-50.
Plummer, M.V., C.S. O’Neal, S.M. Cooper, and R. Stork. 2020. Red-bellied mudsnake (Francia abacura) home ranges increase with precipitation in an isolated wetland. Herpetological Conservation and Biology 15(1): 160-168.
Plummer, M.V., C.S. O’Neal, S.M. Cooper, R. Stork, N.E. Mills, A.B. McKinney. 2020. Leave or die: dispersal of red-bellied mudsnakes (Farancia abacura) from their home ranges in an isolated wetland. Wetlands Conservation (2020): 1-10.
Plummer, M.V., C.S. O’Neal, R. Stork, S.M. Cooper, and A.B. McKinney. In Press. Farancia abacura (Red-bellied mudsnake) Body Temperature. Herpetological Review.
Rivera, P., R. Stork, and A. Hug. 2017. A First Look at the Microbiology of Rabidosa rabida, a Wolf Spider in Searcy, Arkansas. Arkansas Academy of Science. 71(1): 51-55.
Stork, R. 2012. Intraspecific Variation in Thermal Biology of Rabidosa rabida (Araneae: Lycosidae) (Walackenaer 1837) from the Mountains of Arkansas. Environmental Entomology. 41(6): 1631-1637
Stork, R., P. Smith, C. Aaen, and S. Cooper. IN PRESS. Field observations of body temperature for the wolf spider Rabidosa rabida (Walckenaer 1837) (Araneae: Lycosidae) differ from reported lab temperature preference suggesting thermoconforming. Environmental Entomology.
Stork, R. & S. Wilmsen. 2017. Rabidosa rabida (Araneae: Lycosidae) does not require venom injection to capture prey in the lab. Journal of Arachnology.
Teaching Interests:
My teaching interests focus on physiology, both in Animal Physiology and Human Anatomy and Physiology I. I also really enjoy teaching Animal Behavior and mentoring students in student-designed research projects in Animal Physiology and Animal Behavior. I have taught General Biology for nonmajors for several years and coordinated our department’s capstone course, Senior Seminar. I have also collaborated with colleagues in team-teaching Herpetology and Conservation Biology.
Research Interests:
I am particularly interested in how animals physiologically respond to their environment, especially by thermoregulation. This led me to focus my graduate research on the physiological ecology of hibernation at the University of Alaska Fairbanks. My study species were the arctic ground squirrel and the Alaska marmot, and I really enjoyed my time in the field in the Arctic capturing and studying these fascinating animals. I worked with Drs. C. Loren Buck and Brian M. Barnes to record hibernation body temperatures of free-living animals, which allowed us to better understand how these animals tolerate and thrive in the extreme environment in which they live. Under the mentorship of Dr. Diane M. O’Brien, I used stable isotopes as a tool to monitor metabolic fuel use and protein turnover during hibernation. Since there are fewer hibernators facing only moderate temperatures in Arkansas, I am applying the skills I have gained to new projects in animal physiological ecology and behavior at the Gilliam Biological Research Station.
Selected Publications:
Lee, T. N., M. M. Richter, C. T. Williams, Ø. Tøien, B. M. Barnes, D. M. O’Brien, and C. L. Buck. 2017. Stable isotope analysis of CO2 in breath indicates metabolic fuel shifts in torpid arctic ground squirrels. Comparative Biochemistry and Physiology, Part A 209:10-15. doi: 10.1016/j.cbpa.2017.04.004
Lee, T. N., F. Kohl, C. L. Buck, and B. M. Barnes. 2016. Hibernation strategies and patterns in sympatric arctic species, the Alaska marmot and the arctic ground squirrel. Journal of Mammalogy 97:135-144. doi: 10.1093/jmammal/gyv163
Richter, M. M., C. T. Williams, T. N. Lee, Ø. Tøien, G. L. Florant, B. M. Barnes, and C. L. Buck. 2015. Thermogenic capacity at subzero temperatures: How low can a hibernator go? Physiological and Biochemical Zoology 88:81-89. doi: 10.1086/679591
Lee, T. N., C. L. Buck, B. M. Barnes, D. M. O’Brien. 2012. A test of alternative models for increased tissue nitrogen isotope ratios during fasting in hibernating arctic ground squirrels. Journal of Experimental Biology 215:3354-3361. doi: 10.1242/jeb.068528
Lee, T. N., R. W. Fridinger, B. M. Barnes, C. L. Buck, and D. M. O’Brien. 2011. Estimating lean mass over a wide range of body composition: A calibration of deuterium dilution in the arctic ground squirrel. Rapid Communications in Mass Spectrometry 25:3491-3496. doi: 10.1002/rcm.5253
Williams, C. T., A. V. Goropashnaya, C. L. Buck, V. B. Federov, F. Kohl, T. N. Lee, and B. M. Barnes. 2011. Hibernating above the permafrost: effects of ambient temperature and season on expression of metabolic genes in liver and brown adipose tissue of arctic ground squirrels. Journal of Experimental Biology 214:1300-1306.doi: 10.1242/jeb.052159
Sheriff, M. J., G. J. Kenagy, M. Richter, T. Lee, Ø. Tøien, F. Kohl, C. L. Buck, and B. M. Barnes. 2011. Phenological variation in annual timing of hibernation and breeding in nearby populations of Arctic ground squirrels. Proceedings of the Royal Society B 278:2369-2375. doi: 10.1098/rspb.2010.2482
Lee, T. N., B. M. Barnes, and C. L. Buck. 2009. Body temperature patterns during hibernation in a free-living Alaska marmot (Marmota broweri). Ethology Ecology and Evolution 21:403-413.
Plummer, M. V., T. N. Lee, and N. E. Mills. 2008. Effect of a sand substrate on the growth and condition of Apalone mutica hatchlings. Journal of Herpetology 42:550-554.
Lee, T. N., M. V. Plummer, and N. E. Mills. 2007. Utilization of posthatching yolk and external forage to maximize early growth in Apalone mutica hatchlings. Journal of Herpetology 41:492-500.
Teaching Interests:
I completed my Ph.D. in Cellular and Integrative Physiology while working in the lab of Dr. Michael Sturek at Indiana University School of Medicine in Indianapolis, IN. While there, I developed an intense interest in “broken” biology and the ways in which “breaking” normal biological patterns in one body system would affect other body systems. Metabolic syndrome is defined as the clustering of metabolic conditions, including central obesity, hypertension, dyslipidemia, hyperinsulinemia, and glucose intolerance. Interestingly, these metabolic conditions are also risk factors for cardiovascular complications. In particular, I am interested in teasing out the contributions of these risk factors to aberrant intracellular calcium handling in the smooth muscle cells lining the coronary arteries. These changes in calcium handling are associated with increases in atherosclerotic plaque formation, which in turn contributes to mortality due to myocardial infarction.
My graduate work allowed me to ask questions that cover a wide range of biological focus areas, from the molecular biology of calcium handling and overall cell biology to the effect these phenomena have on organ systems and organisms as a whole. This range of questions allowed me to prepare to teach a wide range of courses, including Cell Biology, Molecular and Cellular Biology, Developmental Biology, and Human Anatomy and Physiology. I also coordinate our senior seminar capstone course.
Selected Publications:
Yoder SM, Dineen SL, Wang Z, Thurmond DC. YES, a SRC Family Kinase, Is a Proximal Glucose-specific Activator of Cell Division Cycle Control Protein 42 (Cdc42) in Pancreatic Islet β Cells. JBC 286(16):11476-87. 2014.
Dineen SL, McKenney ML, Bell LN, Fullenkamp AM, Schultz KA, Alloosh M, Chalasani N, Sturek M. Metabolic syndrome abolishes glucagon-like peptide-1 receptor agonist stimulation of SERCA in coronary smooth muscle. Diabetes 64(9):3321-27. 2015.
Highlighted with full commentary: Davies MG, New Insights on the Role of SERCA During Vessel Remodeling in Metabolic Syndrome. Diabetes 64(9):3066-68. 2015.
McKenney-Drake ML*, Rodenbeck SD*, Owen MK, Schultz KA, Alloosh M, Tune JD, Sturek M. Biphasic alterations in coronary smooth muscle Ca2+ regulation in a repeat cross-sectional study of coronary artery disease severity in metabolic syndrome, Atherosclerosis 249:1-9. 2016.
McKenney-Drake ML*, Rodenbeck SD*, Owen MK, Schultz KA, Alloosh M, Tune JD, Sturek M. Repeat cross-sectional data on the progression of the metabolic syndrome in Ossabaw miniature swine, Data in Brief 7:1393-1395. 2016.
Dineen SL, Neeb ZP, Obukhov AG, and Sturek M. Transient receptor potential channels in metabolic syndrome-induced coronary artery disease. Vascular Ion Channels in Physiology and Disease. I. Levitan and A.M. Dopico (Eds). New York, NY: Springer, 2016.
Rodenbeck SD*, Zarse CA*, McKenney-Drake ML, Bruning RS, Sturek M, Chen NX, Moe SM. Intracellular calcium increases in vascular smooth muscle cells with progression of CKD in a rat model, Nephrol Dial Transplant 32(3): 450-458. 2017.
McKenney-Drake ML*, Rodenbeck SD*, Bruning RS, Kole A, Yancey KW, Alloosh M, Sacks H, Sturek M. Epicardial adipose tissue removal potentiates outward remodeling and arrests coronary atherogenesis. Annals of Thoracic Surgery 103(5): 1622-1630. 2017
Badin JK, Eggenberger C, Rodenbeck SD, Hashmi ZA, Wang I-W, Garcia JP, Alloosh M, Sturek M. Intracellular Ca2+ dysregulation in coronary smooth muscle is similar in coronary disease of humans and Ossabaw miniature swine. Journal of Cardiovascular Translational Research 15(1): 167-178. 2022.
Badin JK, Rodenbeck SD, McKenney-Drake ML, and Sturek M. Multiphasic changes in smooth muscle Ca2+ transporters during the progression of coronary atherosclerosis. Ion transport and membrane interactions in vascular health and disease. I. Levitan and M. Sturek (Eds). Cambridge, MA: Academic Press, 2022.
Teaching Interests:
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