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Science 14 June 1985:
Vol. 228. no. 4705, pp. 1284 - 1288
DOI: 10.1126/science.2988128
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Articles

Science, Vol 228, Issue 4705, 1284-1288
Copyright © 1985 by American Association for the Advancement of Science

articles

Biochemical modeling of an autonomously oscillatory circadian clock in Euglena

K Goto, DL Laval-Martin, and LN Edmunds Jr

Eukaryotic microorganisms, as well as higher animals and plants, display many autonomous physiological and biochemical rhythmicities having periods approximating 24 hours. In an attempt to determine the nature of the timing mechanisms that are responsible for these circadian periodicities, two primary operational assumptions were postulated. Both the perturbation of a putative element of a circadian clock within its normal oscillatory range and the direct activation as well as the inhibition of such an element should yield a phase shift of an overt rhythm generated by the underlying oscillator. Results of experiments conducted in the flagellate Euglena suggest that nicotinamide adenine dinucleotide (NAD+), the mitochondrial Ca2+-transport system, Ca2+, calmodulin, NAD+ kinase, and NADP+ phosphatase represent clock "gears" that, in ensemble, might constitute a self-sustained circadian oscillating loop in this and other organisms.


THIS ARTICLE HAS BEEN CITED BY OTHER ARTICLES:
Circadian G2 Arrest as Related to Circadian Gating of Cell Population Growth in Euglena.
A. Bolige, S.-y. Hagiwara, Y. Zhang, and K. Goto (2005)
Plant Cell Physiol. 46, 931-936
   Abstract »    Full Text »    PDF »
Calcium Dynamics and Circadian Rhythms in Suprachiasmatic Nucleus Neurons.
M. Ikeda (2004)
Neuroscientist 10, 315-324
   Abstract »    PDF »
Spermidine Determines the Sensitivity to the Calmodulin Antagonist, Chlorpromazine, for the Circadian Conidiation Rhythm but Not for the Mycelial Growth in Neurospora crassa.
S. Katagiri, K. Onai, and H. Nakashima (1998)
J Biol Rhythms 13, 452-460
   Abstract »    PDF »
Circadian oscillations of cytosolic and chloroplastic free calcium in plants.
C. Johnson, M. Knight, T Kondo, P Masson, J Sedbrook, A Haley, and A Trewavas (1995)
Science 269, 1863-1865
   Abstract »    PDF »
The Role of Extracellular Calcium in Generating and in Phase-Shifting the Bulla Ocular Circadian Rhythm.
S. B. S. Khalsa, M. R. Ralph, and G. D. Block (1993)
J Biol Rhythms 8, 125-139
   Abstract »    PDF »
Phase Shifting of the Circadian Conidiation Rhythm in Neurospora crassa by Calmodulin Antagonists.
H. Nakashima (1986)
J Biol Rhythms 1, 163-169
   Abstract »    PDF »


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