Re: [ISOGEOCHEM] Corn Influenced Diet Shifts?       To give an idea of how quickly the 13C composition of the main energy vector, mouse-liver glycogen, changes (for the evaluation of certain pharmaceuticals) between a C3 and C4 diet, we developed a Stable-Isotopic Indirect Calorimeter (SIIC).  The SIIC  permitted us to evaluate the change of rate CO2 production under the influence of a variety of pharmaceuticals for a good medical cause.  

        For an abstract, see http://www.naturesfingerprint.com/abstracts/abstract_i10272000.shtml  Briefly, the 13C value of glycogen (as parameterized via CO2) varied at 3.3o/oo per hour as the diet was immediately changed from C3 (mouse chow, -25o/oo) to C4 (corn syrup, -12o/oo) values.

        Best Regards,
            John 
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  ----- Original Message ----- 
  From: William Patterson 
  To: [log in to unmask] 
  Sent: Thursday, January 22, 2009 5:57 PM
  Subject: Re: [ISOGEOCHEM] Corn Influenced Diet Shifts?


  Hello Marilyn and others
  If the discussion will go beyond the influence of corn on humans then you may be interested in the following papers by Antoine Zazzo and the references therein. The cows were fed a C3 diet and then switched to a corn diet. A record of this transition is then recovered from tooth dentine and enamel using micromilling techniques.
  Cheers,
  Bill


  Zazzo, A., Balasse, M., and Patterson, W.P. 2006. The reconstruction of mammal individual history: refining high-resolution isotope record in bovine tooth dentine. Journal of Archaeological Science, v. 33, p. 1177-1187.


  Zazzo, A., Balasse, M., and Patterson, W.P. 2005. High-resolution d13C intra-tooth profiles in bovine enamel: Implications for mineralization pattern and isotopic attenuation. Geochimica et Cosmochimica Acta, v. 69, no. 14, p. 3631-3642.


    Dear Folks,


    I received this message from a colleague who is teaching students about the influence of corn. Do any of you alert readers have a reference at your fingertips that you could recommend for Charlie?


    "Next Tuesday Washington College is hosting a viewing of the movie "King
    Corn," which is a critique of the use of corn products in our country (see
    description below).

    One of the most fascinating things I heard about this issue was in one of
    your talks: The stable isotope evidence that Europeans coming to the US
    experience a shift in their carbon isotope ratios in response to the
    corn-heavy diet.  Does that data appear in publication anywhere? I would
    love to bring that up at the viewing of this movie during the discussion
    period."



    Marilyn Fogel



    Dr. Marilyn L. Fogel

    Geophysical Laboratory

    Carnegie Institution of Washington

    5251 Broad Branch Rd., NW

    Washington, DC 20015

    Phone (202) 478-8981

    Main office (202) 478-8900

    FAX (202) 478-8901

    Website: http://fogel.gl.ciw.edu/




-- 
Dr. William P. Patterson
  Professor and Director of the Saskatchewan Isotope Laboratory
  Department of Geological Sciences
  University of Saskatchewan
  114 Science Place
  Saskatoon SK S7N 5E2
  Canada
  Phone: 306-966-5691(office); 306-966-5712(lab)
  Email: [log in to unmask]
  Web: http://geochemistry.usask.ca/bill.html