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Research Spending & Results

Award Detail

Doing Business As Name:University of Alaska Fairbanks Campus
  • Cory T Williams
  • (907) 980-4889
Award Date:12/04/2017
Estimated Total Award Amount: $ 637,390
Funds Obligated to Date: $ 637,390
  • FY 2018=$281,000
  • FY 2016=$75,390
  • FY 2017=$281,000
Start Date:08/13/2017
End Date:08/31/2019
Transaction Type:Grant
Awarding Agency Code:4900
Funding Agency Code:4900
CFDA Number:47.074
Primary Program Source:040100 NSF RESEARCH & RELATED ACTIVIT
Award Title or Description:Collaborative Research: Neuroendocrine Modulation of Circannual Rhythms in Mammals
Federal Award ID Number:1806216
DUNS ID:615245164
Parent DUNS ID:048679567
Program Officer:
  • Edda (Floh) Thiels
  • (703) 292-8167

Awardee Location

Street:West Ridge Research Bldg 008
Awardee Cong. District:00

Primary Place of Performance

Organization Name:University of Alaska Fairbanks Campus
Street:902 N. Koyokuk Dr.
Cong. District:00

Abstract at Time of Award

Predicting how species might alter their annual timing in response to rapid environmental change, including changes in climate, is constrained by insufficient knowledge of the endogenous mechanisms animals use to keep time, the cues used to adjust timing, and the extent to which programmed seasonal cycles are physiologically malleable or plastic. This project investigates the mechanisms that underlie plasticity in the seasonal induction of the neuroendocrine signals that trigger the termination of hibernation and the onset of reproduction in ground squirrels. Unlike most mammals, ground squirrels spontaneously become reproductively competent in constant darkness, without the stimulus of a changing photoperiod. As such, ground squirrels are an ideal organism for studies examining non-photoperiodic control of reproductive timing. Establishing the neuroendocrine mechanisms responsible for transitions between life-history stages will identify target genes for monitoring adaptive genetic responses to environmental change. This investigation integrates research and learning by training graduate students in ecophysiology and neurophysiology, providing opportunities for undergraduates to participate in laboratory experiments. The project also includes outreach to Alaska Native and American Indian high school students and undergraduates for inclusion in research and aims to increase K-12 students' understanding of and engagement in research by participating in Teacher Research Experience programs. In hibernating mammals, a precise integration must occur between the central nervous system signaling cascades controlling thermoregulation through the termination of torpor and the subsequent activation of the reproductive axis; however, the neuroendocrine modulators that regulate these changes and how they are integrated are unknown. In seasonally breeding, photoperiodic vertebrates, the pars tuberalis (PT) of the pituitary plays an essential role in the timing of annual cycles, as it alters hypothalamic thyroid hormone availability by secreting thyroid stimulating hormone in a light- or melatonin-sensitive manner, which acts on neighboring hypothalamic deiodinase expressing cells. The PT thyrotrophs themselves are now considered strong candidates for circannual timer cells, driving a thyroid-dependent seasonal physiology. This research tests the hypothesis that, in the absence of any photic cues, the termination of torpor and onset of reproduction are triggered by spontaneous changes in hypothalamic thyroid status driven by activation of thyrotroph cells in the PT. Additionally, the project tests the hypothesis that plasticity in timing is driven by temperature-induced changes in hypothalamic deiodinase activity and/or through effects on downstream targets of the triiodothyronine signaling pathway that occur independent of the PT.

Publications Produced as a Result of this Research

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Williams CT, Barnes BM, Yan L, Buck CL "Entraining to the polar day: circadian rhythms in arctic ground squirrels" Journal of Experimental Biology, v.220, 2017, p.3095. doi:doi: 10.1242/jeb.159889 

Williams CT, Buck CL, Sheriff MJ, Richter MM, Krause JS, Barnes BM "Sex-dependent phenological plasticity in an arctic hibernator." American Naturalist, v.190, 2017, p.854. doi: 

Williams CT, Klassen M, Barnes BM, Buck CL, Arnold W, Giroud S, Vetter SG, Ruf T "Seasonal reproductive tactics: annual timing and the capital-to-income breeder continuum" Philosophical Transactions of the Royal Society B, v.372, 2017, p.20160250. doi:DOI: 10.1098/rstb.2016.0250 

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