Stephen M. Secor

Professor

Phone: (205) 348-1809

Email: ssecor@ua.edu

Dr. Secor’s Lab Webpage

Stephen Secor received a Ph.D. in Biology from the University of California at Los Angeles in 1992 and completed his postdoctoral research at the UCLA School of Medicine. He was appointed Assistant Professor at the University of Alabama in 2001. Dr. Secor has been an Associate Professor at the University of Alabama since 2006.

Research Interests

My laboratory explores the how’s and why’s of physiological design. Our primary physiological system is the digestive system, where we investigate the integrative design of gastrointestinal morphology and function. Our projects fall under two long-term interests; (1) the adaptive interplay between feeding habits and digestive physiology, and (2) the integrative mechanisms underlying the regulation of physiological performance.  For the former project, we take a broad comparative approach using fishes, amphibians, and reptiles to explore the adaptive link between natural feeding frequency and the capacity to regulate gastrointestinal performance.  The second program uses the Burmese python model to investigate the signals and cellular pathways involved in the plasticity of tissue structure and function in response to fasting and digestion.

Our evolutionary studies on gastrointestinal design and responses are aimed at describing why there exist a clear dichotomy in the regulation of gastrointestinal performance with feeding and fasting.  From our studies of over 50 species of fishes, amphibians, and reptiles, we have  found that species that feed frequently in the wild regulate their intestinal performance very modestly, whereas those species that naturally experience long intervals between meals regulate their intestinal performance over much greater ranges.  Interestingly, this capacity to widely regulate intestinal performance has independently evolved several times.  We proposed that energy conservation during fasting has been the selective pressure underlying the evolution of the wide regulation of gastrointestinal performance for infrequently feeding vertebrates.

Our comparative studies also include a long standing interest in specific dynamic action (the cost of meal digestion and assimilation) and the allometry of metabolic and digestive performance.  For the former we are characterizing the SDA responses of amphibians and reptiles to identify the effects of meal size, type, and composition, body temperature and size, and phylogeny on this physiological response.  For the latter projects, we are examining both intraspecific and interspecific scaling relationships among amphibians and reptiles of standard metabolic rate, activity metabolism, SDA, and gastrointestinal mass and performance.

Using the python we are exploring the integrative signals, cellular, and molecular mechanisms that underlie the regulation of gastrointestinal performance.  Key questions are: how does the python shut down gastric acid production after feeding, what is responsible for the rapid postfeeding growth of the intestine, liver, pancreas, and kidneys, and what processes are involved in the wide regulation of intestinal function.  Python exhibits the unprecedented response of rapidly lengthening and shortening their microvilli with the start and finish of each meal.  This dramatically alters the functional surface area of the gut.  Our studies are examining the molecular/cellular events that are responsible for this complex response.  In collaboration with Dr. Todd Castoe (University of Texas, Arlington), we are exploring gene expression programs responsible for the regulation of intestinal performance for pythons and other snakes, facilitated by our 2013 publication of the python genome. Other related projects include describing the pythons’ capacity to remove calcium from their diet, the signals that induce their postprandial cardiac hypertrophy, and the plasticity and spatial diversity of their gut microbiota.

I welcome collaboration with other researchers on projects in digestive physiology and metabolism and encourage undergraduate and graduate students and post-doctoral researchers to join my lab and become involved in an exciting series of current and future studies.  View my lab website at http:/bama.ua.edu/~ssecor/index.html

 

Selected Publications

Castoe T.A., A.P.J de Koning, K.T. Hall, D. C. Card, D.R. Schield, M.K. Fujita, R.P. Ruggiero, J.F. Degner, J.M. Daza, W. Gu, J. Reyes-Velasco, K.J. Shaney, J.M. Castoe, S.E. Fox, A.W. Poole, D. Polanco, J. Dobry, M.W. Vandewege, Q. Li, R. Schott, A. Kapusta, P. Minx, C. Feschotte, P. Uetz, D. Ray, F. Hoffman, R. Bogden, E.N. Smith, B.S.W. Chang, F. Vonk, N.R. Casewell, C. Henkel, M.K. Richardson, S.P. Mackessy, A.M. Bronikowski, M. Yandell, W.C. Warren, S.M. Secor, D.D. Pollock. 2013. The Burmese python genome reveals the molecular basis for extreme adaptation in snakes. Proc. Natl. Acad. Sci. 110:20645-20650.

Jacobson, E.R., D.G. Barker, T. Barker, R. Mauldin, M.L. Avery, R. Engeman and S.M. Secor. 2012. Environmental temperatures, physiology, and behavior limit the range expansion of invasive Burmese python in southeastern US. Integr. Zool. 7:271-285.

Secor, S.M., J.R. Taylor and M. Grosell. 2012. Selected regulation of gastrointestinal acid-base secretion and tissue metabolism for the diamondback water snake and Burmese python. J. Exp. Biol. 215:185-196.

Riquelme, C.A., J.A. Magida, B.C. Harrison, C.E.Wall, T.G. Marr, S.M. Secor and L.A. Leinwand. 2011. Fatty acids identified in the Burmese python promote beneficial cardiac growth. Science. 334:528-531.

Secor, S.M. and S.E. White. 2010. Prioritizing blood flow, cardiovascular performance in response to the competing demands of locomotion and digestion for the Burmese Python, Python molurus.J. Exp Biol. 213:78-88

Costello, E.K., J.I. Gordon, S.M. Secor, and R. Knight. 2010. Postprandial remodeling of the gut microbiota in Burmese python. ISME J. 4:1375-1385.

Secor, S.M. 2009. Specific dynamic action, a review of the postprandial metabolic response.J. Comp. Physiol. 179:1-56.

Cox, C.L. and S.M. Secor.  2008. Matched regulation of gastrointestinal performance in the Burmese python, Python molurus. J. Exp. Biol. 211:1131-1140.

Secor, S.M. 2008. Digestive physiology of the Burmese python, broad regulation of integrated performance. J. Exp. Biol. 211:3767-3774.

Secor, S.M.  2005.  Evolutionary and cellular mechanisms regulating intestinal performance of amphibians and reptiles.  Integr. Comp. Biol. 45:66-78.

Secor, S.M., D. Fehsenfeld, J. Diamond, and T. E. Adrian.  2001. Responses of python gastrointestinal regulatory peptides to feeding. Proc. Natl. Acad. Sci. 98:13637-13642.

Secor, S.M. and J. Diamond.  1998.  A vertebrate model of extreme physiological regulation. Nature 395:659-662.