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Dr. Harold Zakon

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Office: PAT 328

Lab: PAT 329

phone: (512) 471-0194

fax: 471-9651

email: h.zakon [at] austin.utexas.edu

 

My Curriculum Vitae

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Harold Zakon received his Ph.D. in Neurobiology & Behavior from Cornell University in 1981 and did postdoctoral research at the Scripps Institution of Oceanography, the University of California at San Diego from 1981-1983. He joined the former Zoology Department at the University of Texas in 1983. He was the first Chairman of the Section of Neurobiology when it was founded in 1999. He has served on grant review panels at the NIH, editorial boards of a number of scientific journals and advisory boards of scientific societies. He has won awards for his research, such as an NIH Research Career Development Award and a Research Award from the Alexander von Humboldt Foundation, as well as teaching excellence at UT. He has been a director and faculty member of the “Neural Systems and Behavior” summer course at the Marine Biological Laboratory in Woods Hole, Massachusetts (1995-2005), and the Chairman of international meetings including the “Gordon Research Conference in Neuroethology” at Oxford University (1999, 2002) and the International Society for Neuroethology (2010). He holds a position as Adjunct Scientist at the Marine Biological Laboratory in Woods Hole, MA. He was a visiting Fellow at the University of Cambridge (2012) and at the Ludwig Maximilian University and University of Konstanz in Germany (2015).

Research Interests

We study the function, regulation, and evolution of voltage-gated ion channels, the membrane proteins responsible for electrical excitability of the brain.

1) Adaptive Evolution of Ion Channels in Electric Fish

Electric fish live in murky waters and are nocturnally active. They generate weak electric fields around themselves from a specialized electric organ derived from muscle cells, and sense these electric fields, with specialized sensory receptors. They sense the distortions caused in their own electric fields to locate nearby objects, and use their electric fields to broadcast electric signals other fish.

The electric organ discharge varies across species, is different in the two sexes, and varies in each individual. It is influenced by social factors and hormones, and shows circadian variations as well. These discharges can be easily recorded in freely behaving animals. The circuitry for generating them is simple and many of the cells are accessible for electrophysiological analysis. Their genes are known. Thus, we can study dynamic biophysical events in excitable membranes from the level of freely behaving animals to that of the ion channels themselves, and their genes. We mainly study the regulation of sodium and potassium currents in the electric organ by sex steroid hormones (which drive sex differences in the discharge) and phosphorylation (which accounts for circadian variations). (Markham et al., 2009: PLoS Biology)

2) Convergent Evolution of the Electric Organ
Electric organs have evolved multiple times in fish, each time from muscle. We study the molecular and developmental mechanisms whereby a differentiated muscle cell has evolved into a novel type of cell--an electric organ cell—(a problem first posed by Charles Darwin in the “Origin of Species”) as a model for understanding the molecular basis of convergent evolution of a trait. (Gallant et al., 2014: Science)

3) Deep evolution of ion channels and other genes
Where did ion channel genes (or any other genes for that matter) come from during evolution of life? We study the history of ion channel and other genes in bacteria, single celled eukaryotes, and at the origin of multicellular animal life. We are now investigating various brain-expressing genes during the transition of vertebrates from water to land. (Liebeskind et al., 2011: Proceedings of the National Academy of Sciences USA; Liebeskind et al., 2013 Current Biology).

4) Adaptive Evolution of Ion Channels as a Countermeasure Against Venoms

A number of animals have evolved venoms against their prey or to defend themselves against their predators. We study how ion channels have evolved resistance to the toxins that they animals themselves carry (tetrodotoxin, in pufferfish, newts and frogs; pumiliotoxin and other toxins in poison arrow frogs) or to which they are exposed when taking venomous prey. (Rowe et al, 2013: Science).