TITLE:
Ultradian oscillators of the circadian clock in Saccharomyces cerevisiae
AUTHORS:
Sara S. Dick, Aya Ryuzoji, Dorothy M. Morré, D. James Morré
KEYWORDS:
Biological Clock; ECTO-NOX (ENOX) Proteins; Ultradian Oscillator; Yeast (Saccharomyces cerevisiae)
JOURNAL NAME:
Advances in Biological Chemistry,
Vol.3 No.1,
February
26,
2013
ABSTRACT: The yeast, Saccharomyces cerevisiae, has an ENOX1
activity with a period length of 24 min similar to that of other eukaryotes. In
contrast to other eukaryotes, however, Saccharomyces
cerevisiae has a second ENOX1-like activity with a period length of 25 min.
The latter is distinguishable from the traditional ENOX1 on the basis of the
longer period length along with resistance to an ENOX1 inhibitor, simalikalactone
D, and failure to be phased by melatonin. In addition, two periods are apparent
in measurements of oxygen consumption indicating that the consumption of
oxygen to water occurs independently by homodimers of both of the two forms of
ENOX. Based on the measurements of glyceraldehyde-3- phosphate
dehydrogenase, S. cerevisiae exhibits
circadian activity maxima at 24 and 25 h together with a 40 h period possibly
representing the 40 min metabolic rhythm of yeast not observed in our measurement of oxygen consumption and normally observed only with continuous cultures.
The findings are indicative of at least three independent time-keeping
systems being operative in a single cell.