Re: Biomedical Research/carbon 14

["Bjorn Cedervall" <bcradsafers@HOTMAIL.COM>]

The works by M. Calvin (photosynthesis) or H.A. Krebs (1900-1981, citric 

acid cycle) could give some initial ideas - and probably upper limits (the 

detection systems are better today):



M. Calvin and J.A. Bassham: The Photosynthesis of carbon compounds, 

Benjamin, New York, 1962.



H.A. Krebs and J.M. Lowenstein, The Tricarboxylic Acid Cycle, in D.M. 

Greenberg (ed.), Metabolic PAthways, Vol. I, Academic Press, New York, 1960, 

p. 129.



H. Krebs, The History of the Tricarboxylic Acid Cycle, Perspect. Biol. Med., 

14: 154-170 (1970). From:

http://www.ruf.rice.edu/~bioslabs/studies/mitochondria/krebs.html



Then look for references therein - or try any other path to works by Melvin 

Calvin (1950:ies) or Hans Krebs (1930-40:ies) directly.



I think that the amounts or concentrations of C-14 may vary much (orders of 

magnitudes) depending on the contexts (How many cells will be used? How many 

molecules can be expected to be radiolabeled?). Many pulsed field gel 

electrophoresis, PFGE (labeling of DNA) have included C-14 labeled DNA - 

typically to label 200 000 cells or more per sample that is analyzed. Lots 

of old molecular genetics experiments (phages, bacteria stuff from the 

1950-60:ies) included C-14. The cell cycle has often been followed with C-14 

thymidine for the labeling of  DNA in the replication/duplication phase).



For DNA labeling (PFGE) the order of 0.3 - 1.0 kBq per of medium may be the 

approx. amount.



Many others can probably give more precise and direct examples.



Bjorn Cedervall   bcradsafers@hotmail.com

http://www.geocities.com/bjorn_cedervall/

-----------------------------------------

>Can someone in the biomedical community give me a typical activity used in 

>a genetic or metabolic study using carbon-14?  I would need to know, for 

>example, how much activity per sample, and how many samples would typically 

>be labeled, in one "experiment."





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