Research Interests


 

Primary research interest:

            Questions related to the physiological challenges faced by high latitude vertebrates.
 

Research foci:

    Since arriving in Alaska, I have worked on four, in some cases overlapping, research foci:
        * Dual-Energy X-ray absorptiometry,
        * the Physiological ecology of non-hibernating high-latitude rodents (voles & lemmings),
        * Wax esters, fatty acid signature analysis & dietary studies in seabirds, and
        * Diabetes and alcohol-related disorders in laboratory rats

1)  Dual-Energy X-ray Absorptiometry

          Shortly before leaving Israel in 2002, I became involved in a project to test the applicability of Dual Energy X-ray Analysis to accurately measure the body-condition of small migratory birds.  After coming to Alaska, I purchased a small DXA machine using my start up funds and together with my PhD student, Kalb Stevenson, and a number of NIH NIDDK students, most notably Ryan Wilson, I validated the use of this machine for studies on small mammals and for studies of the organ composition of larger mammals.  These validations were successful and have since been published (as has the validation of the work on migratory birds).  The purchase and validation of this tool has been of considerable value to me as I have used it extensively in my second and third research foci: the physiology of non-hibernating rodents and the links between regular drinking and diabetes and other disorders in rats.

Publications: 

  1. Stevenson*, K.T., I.G. van Tets and D.Y. Chon*  2009  Making no bones about it: Bone mineral density changes seasonally in a non-hibernating Alaskan rodent, the northern red-backed vole (Myodes rutilus).  Journal of Mammalogy 90(1):25-31.  Click here for PDF version

  2. Stevenson*, K.T. and I.G. van Tets.  2008. Dual-Energy X-ray Absorptiometry (DXA) can accurately and nondestructively measure the body composition of small, free-living rodents.  Physiological and Biochemical Zoology.  81(3):373-382 Click here for PDF version
  3. Lindner* S. and I.G. van Tets.  2006, Using Dual-Energy X-ray Absorptiometry to measure the effects of alcohol on the composition of rats' livers, hearts & kidneys.  Ethnicity and Disease. 16(4) (Suppl. 5): 11-12.  Click here for PDF version

  4. Wilson*, R.L. and van Tets, I.G. 2006.  Using Dual-Energy X-ray Absorptiometry to measure the effect of alcohol abuse on the bones and fat deposits of Long Evans rats.  Ethnicity and Disease.  16(4) (Suppl. 5): 27-28. Click here for PDF version

  5. Jackinsky* J. and van Tets, I.G.  2005    Measuring Changes In Organ Composition Using Dual Energy X-ray Absorptiometry; potential for rodent studies on alcoholism.  Ethnicity and Disease. 15 (Suppl. 4): 45-46  Click here for PDF version

  6. Wilson* R. and van Tets, I.G..  2005  Using Dual Energy X-ray absorptiometry to measure limb and digestive organ composition in laboratory rats.  Ethnicity and Disease. 15 (Suppl. 4): 20-21. Click here for PDF version

  7. Korine C., Daniel S., van Tets, I.G., Yosef, R. and Pinshow, B.  2004  Measuring fat mass in small birds by dual-energy X-ray absorptiometry.  Physiological and Biochemical Zoology77(3): 522-529  Click here for PDF version

 

2)  Physiological Ecology of non-hibernating high-latitude rodents. (supported by NSF grant: 0616245)
 
         

Several small rodent species do not hibernate during winter but instead survive and even reproduce in under snow tunnels and feed on frozen vegetation.  How they do so, and what effect freezing has on the nutritional quality of their food and the rodents’ ability to process it, has not yet been studied in any detail and has potentially important implications for their reproduction, foraging and life history strategies.  Understanding the mechanisms that enable the rodents to do this will not only further our understanding of a much neglected (in comparison to hibernation and migration) arctic survival strategy but may help us finally understand the processes that underpin lemming population cycling.  My studies on these mechanisms are currently funded by the NSF's functional & regulatory systems cluster, grant: 0616245).  Additional funding has been provided at various times through:  NOAA's IPY program, the UAA Chancellor's fund and a UAA Faculty Development Grant.

            Two students are currently working on this foci (both funded by the NSF FRS grant): Kalb Stevenson - a UAA/UAF PhD student and Jacob Templin - a UAA M.S. student.  Jacob's work is further supported through a collaboration with the Alaska Zoo.  Most of our work to date has focused on the Northern red-backed vole, Myodes rutilus.  Free-living populations are common near both Anchorage and Fairbanks and we have also been able to work with captive populations at UAF (through the collaboration of Dr. Abel Bult-Ito) and the Alaska Zoo.  We are also continuing to study brown lemmings, Lemmus sibiricus, in and around Barrow with the help of the Barrow Arctic Science Center and the collaboration of Dr. Denver Holt.

Publications: 

  1. Stevenson*, K.T., I.G. van Tets and D.Y. Chon*  2009  Making no bones about it: Bone mineral density changes seasonally in a non-hibernating Alaskan rodent, the northern red-backed vole (Myodes rutilus).  Journal of Mammalogy 90(1):25-31.  Click here for PDF version

  2. Stevenson*, K.T., I.G. van Tets and L.A. Nay.*  2009  The seasonality of reproduction in photoperiod responsive and non-responsive northern red-backed voles (Myodes rutilus) in south central Alaska.  Canadian Journal of Zoology 87(2):152-164.  Click here for PDF version

  3. Chon*, D.Y., K.T. Stevenson* and I.G. van Tets.  2008.  Seasonal changes in bone mineral density in the northern red-backed vole; A potential model organism for disuse osteoporosis.  Ethnicity and Disease 18(2) (Suppl. 1): 32-34.  Click here for PDF version

  4. Stevenson*, K.T. and I.G. van Tets.  2008. Dual-Energy X-ray Absorptiometry (DXA) can accurately and non-destructively measure the body composition of small, free-living rodents.  Physiological and Biochemical Zoology.  81(3):373-382.  Click here for PDF version

  5. Nay* L., K.T. Stevenson* and I.G. van Tets.  2007. Seasonal Changes in the Reproductive Organs and Body Condition of Northern Redbacked Voles (Clethrionomys rutilus). Ethnicity and Disease 17(4) (Suppl. 5): 58-60 Click here for PDF version

3)  Regular alcohol use and the development of type II diabetes 

        At the beginning of summer 2004, I was approached by faculty associated with the WWAMI biomedical program and asked if I could mentor two Alaska Native high school students in a biomedical research project as part of the then new to Alaska NIH NIDDK student research program.  The two students, Ryan Wilson – a high school junior from Wasilla and Jolene Jackinski – a high school junior who attended Mt. Edgecumbe high school, worked with me through the summer on projects related to the applicability of DXA technology to medical research.  Ryan worked on its ability to identify and quantify the types of compositional changes in rat bones and organ structures that could be expected to occur as a result of long-term changes in dietary and exercise regimes.  Jolene worked on a similar question with respect to organs that were likely to be affected by long term moderate exposure to alchohol.  The rats were provided by Dr. Eric Murphy of the Dept. of Psychology.  Both students did very well and Jolene won an honorable mention (3rd place) prize at the program’s national conference that year for her presentation.  Ryan continued his research with me the following summer and found alcohol-linked patterns of fat deposition in these rats that are likely to lead to increased risk of diabetes.  Ryan’s observation was particularly interesting as the levels at which these rats drink are often cited in the popular press as beneficial levels for humans because of their supposed benefits to cardiac health and it was from this observation and through my continued collaboration with Dr. Murphy that I developed this particular foci.

           The individual elements of this research, and of parallel behavioural research by students supervised by Dr. Eric Murphy have been published as short articles in Ethnicity and Disease.  Now that we have a year of complete, controlled and rigorous data, Dr. Murphy and I are preparing a more substantial manuscript for obesity discussing both the behavioral and the physiological consequences of regular moderate alcohol use for Long Evans rats.

Publications: 

  1. Anahonak*, J., K.T. Stevenson*. and I.G. van Tets.  In press.  Gonadotropin-Inhibitory Hormone, GnIH, and Gonadotropin-Releasing Hormone, GnRH, Activity in the Brain of the Northern Red-back Vole, Myodes rutilusAccepted for publication in Ethnicity and Disease

  2. Infante* S. and I.G. van Tets.  In press.  Symptoms of Alcohol-Induced Liver Disease in Rats that Regularly Drink Alcohol. Accepted for publication in Ethnicity and Disease

  3. Aparicio*, J. and I.G. van Tets.  2008.  Symptoms of type II diabetes in the urine of rats that regularly drink alcohol.  Ethnicity and Disease 18(2) (Suppl. 1): 49-50. Click here for PDF version.

  4. Infante* S. and I.G. van Tets.  2008.  Symptoms of Alcohol-Induced Liver and Heart Disease in Rats that Regularly Drink Alcohol. Ethnicity and Disease 118(2) (Suppl. 1): 79-80. Click here for PDF version.

  5. Lim* F-F and I.G. van Tets.  2007., Do rats that Frequently Drink Alcohol Deposit Fats in a Way that Increases Their Risk of Type II Diabetes?  Ethnicity and Disease 17(4) (Suppl. 5): 30-32 Click here for PDF version.

  6. Lindner* S. and I.G. van Tets.  2006, Using Dual-Energy X-ray Absorptiometry to measure the effects of alcohol on the composition of rats' livers, hearts & kidneys.  Ethnicity and Disease. 16(4) (Suppl. 5): 11-12.  Click here for PDF version.

  7. Wilson*, R.L. and van Tets, I.G. 2006.  Using Dual-Energy X-ray Absorptiometry to measure the effect of alcohol abuse on the bones and fat deposits of Long Evans rats.  Ethnicity and Disease.  16(4) (Suppl. 5): 27-28.  Click here for PDF version

  8. Jackinsky* J. and van Tets, I.G.  2005    Measuring Changes In Organ Composition Using Dual Energy X-ray Absorptiometry; potential for rodent studies on alcoholism.  Ethnicity and Disease. 15 (Suppl. 4): 45-46. Click here for PDF version.

  9. Wilson* R. and van Tets, I.G..  2005  Using Dual Energy X-ray absorptiometry to measure limb and digestive organ composition in laboratory rats.  Ethnicity and Disease. 15 (Suppl. 4): 20-21. Click here for PDF version.

 

4)  wax esters and seabirds
 

        Arctic zooplankton contain unusually high levels of wax esters - sometimes as much as 50% of their total lipid stores - and the ability or inability to use this potential energy source should have dramatic implications for the fitness of those arctic birds and mammals that feed on plankton eating fish.    My MS student, Naomi Bargmann has, with the support of Dr. Scott Hatch and funding from the USGS, completed validations of the use of fatty acid signature analysis as a tool for identifying the components of the diet of black-legged kittiwakes.  It is my intention to develop a comprehensive NSF-funded research program that will among other things:

- develop quantitative and qualitative techniques for determining seabird diets

- identify the energetic composition of these diets and the digestibility of these components (a step that in itself will be of considerable value to those involved in wildlife management) with particular emphasis on the percentage and type of wax in the diet and its digestibility

- determine the mechanisms by which the wax is absorbed, metabolized and used

- determine the mechanisms by which the toxins associated with wax digestion are processed

- investigate the ecological consequences of wax digestion/non-digestion for seabirds and marine mammals.

Publications: 

  1. Burns, J.M., Williams, T.M., Secor, S.M., Owen-Smith, N., Bargmann, N.A., Castellini, M.A. 2006.  New insights into the physiology of foraging.  Physiological and Biochemical Zoology.  79(2): 242-249.  Click here for PDF version.

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If you are interested in working with me on any of these projects you can click here to contact me via email or you can write to me c/-

Department of Biological Sciences, EBL
University of Alaska, Anchorage
3211 Providence Drive
Anchorage, AK 99508  USA

 

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This page was last edited on:  26 February 2009