14 Oscillations, Rhythms and Synchronized Time Bases …
233
Rates of O 2 consumption during the respiration of the yeast cell division cycle
were shown to be a discontinuous (oscillatory) process proceeding in in selectionsynchronized cultures [135, 136].
Observations of short term rhythms of protein synthesis (period ~1 h) in a variety
of mammalian tissues and cultured cells as noted over the previous years in the Soviet
journals from 1967 was reviewed in the Western literature [10, 11]. In synchronous
cultures of Schizosaccharomyces pombe, inhibitor sensitivities and activity of mitochondrial ATPase oscillated [29]. In Acanthamoeba castellanii, oscillatory respiration was accompanied by synchronized total cellular protein and RNA accumulation [30, 31], and also by accumulation of ATPase activity, enzyme protein and
F 1 -ATPase inhibitor [32]. Temperature compensation of these respiratory oscillations was revealed, and hence their probable functions as rhythms with timekeeping
or synchronizing activities [95, 118]. Quantal increments in cell-division cycle times
at decreasing temperatures from 30 to 20 °C were noted. Similar quantization of division times in cultured mammalian cells had previously been observed and modeled
as a limit cycle oscillator with added noise [69, 88, 149].
14.1.10 Time Structure Discovered in Self-synchronous Yeast
Continuous Cultures
Detailed mapping of the temporally organized structure of a cell and requires either
the production of unperturbed populations of individuals growing and performing
in synchrony [13, 63, 64, 90, 136, 150–152], or measurements made on single cells
[5, 8, 133, 138]. The former method provides large enough sampled populations
for physiological and biochemical assays, whereas possible time averaging from
imperfect, perturbed synchrony, or specific population effects are avoided from the
latter.
A pivotal development was described and implemented by the group of Hiroshi
Kuriyama at Tsukuba. They first devised and perfected the conditions enabling the
growth of laboratory scale self-synchronous continuous culture. These studies have
enabled highly significant advances in the resolution of time structure of yeast, an
invaluable experimental model system, and at present the most fully investigated of
any organism [67, 68, 147]. The temperature compensated period in yeast [128] of
the ~40 min period in yeast strongly suggested a time-keeping function, just as for
the ultradian ~65 min rhythm in Acanthamoeba castellanii [95], and the circadian
(~24 h) expression of bioluminescence in Gonyaulax (now Lingulodinium) polyedra,
a dinoflagellate [57]. Glutathione is a central player in the redox cycle that sustains
the respiratory oscillation [127], confirming the ideas of Rapkine [140], and that thiol
cycling is the key to the generation of cellular respiratory rhythms [92]. Mitochondrial
respiratory (adenylate) control [15] is also at the very core of the ultradian rhythms,
not only in yeast [97, 101], but also in protists [85, 104].
233
Rates of O 2 consumption during the respiration of the yeast cell division cycle
were shown to be a discontinuous (oscillatory) process proceeding in in selectionsynchronized cultures [135, 136].
Observations of short term rhythms of protein synthesis (period ~1 h) in a variety
of mammalian tissues and cultured cells as noted over the previous years in the Soviet
journals from 1967 was reviewed in the Western literature [10, 11]. In synchronous
cultures of Schizosaccharomyces pombe, inhibitor sensitivities and activity of mitochondrial ATPase oscillated [29]. In Acanthamoeba castellanii, oscillatory respiration was accompanied by synchronized total cellular protein and RNA accumulation [30, 31], and also by accumulation of ATPase activity, enzyme protein and
F 1 -ATPase inhibitor [32]. Temperature compensation of these respiratory oscillations was revealed, and hence their probable functions as rhythms with timekeeping
or synchronizing activities [95, 118]. Quantal increments in cell-division cycle times
at decreasing temperatures from 30 to 20 °C were noted. Similar quantization of division times in cultured mammalian cells had previously been observed and modeled
as a limit cycle oscillator with added noise [69, 88, 149].
14.1.10 Time Structure Discovered in Self-synchronous Yeast
Continuous Cultures
Detailed mapping of the temporally organized structure of a cell and requires either
the production of unperturbed populations of individuals growing and performing
in synchrony [13, 63, 64, 90, 136, 150–152], or measurements made on single cells
[5, 8, 133, 138]. The former method provides large enough sampled populations
for physiological and biochemical assays, whereas possible time averaging from
imperfect, perturbed synchrony, or specific population effects are avoided from the
latter.
A pivotal development was described and implemented by the group of Hiroshi
Kuriyama at Tsukuba. They first devised and perfected the conditions enabling the
growth of laboratory scale self-synchronous continuous culture. These studies have
enabled highly significant advances in the resolution of time structure of yeast, an
invaluable experimental model system, and at present the most fully investigated of
any organism [67, 68, 147]. The temperature compensated period in yeast [128] of
the ~40 min period in yeast strongly suggested a time-keeping function, just as for
the ultradian ~65 min rhythm in Acanthamoeba castellanii [95], and the circadian
(~24 h) expression of bioluminescence in Gonyaulax (now Lingulodinium) polyedra,
a dinoflagellate [57]. Glutathione is a central player in the redox cycle that sustains
the respiratory oscillation [127], confirming the ideas of Rapkine [140], and that thiol
cycling is the key to the generation of cellular respiratory rhythms [92]. Mitochondrial
respiratory (adenylate) control [15] is also at the very core of the ultradian rhythms,
not only in yeast [97, 101], but also in protists [85, 104].