Clock Control of Ultradian Respiratory Oscillation Found during Yeast Continuous Culture

Abstract

A short-period autonomous respiratory ultradian oscillation (period Ϸ 40 min) occurs during aerobic Saccharomyces cerevisiae continuous culture and is most conveniently studied by monitoring dissolved O 2 concentrations. The resulting data are high quality and reveal fundamental information regarding cellular dynamics. The phase diagram and discrete fast Fourier transformation of the dissolved O 2 values revealed a square waveform with at least eight harmonic peaks. Stepwise changes in temperature revealed that the oscillation was temperature compensated at temperatures ranging from 27 to 34°C when either glucose (temperature quotient [Q 10 ] ‫؍‬ 1.02) or ethanol (Q 10 ‫؍‬ 0.82) was used as a carbon source. After alteration of the temperature beyond the temperature compensation region, phase coherence events for individual cells were quickly lost. As the cell doubling rate decreased from 15.5 to 9.2 h (a factor of 1.68), the periodicity decreased by a factor of 1.26. This indicated that there was a degree of nutrient compensation. Outside the range of dilution rates at which stable oscillation occurred, the mode of oscillation changed. The oscillation in respiratory output is therefore under clock control.Oscillatory dynamics, which range from those observed in particle physics to those of yearly clocks, are ubiquitous, and in most cases knowledge concerning the underlying processes that dictate the time base, synchronization, and regulation of systems remains rudimentary. In living organisms dynamic behavior provides a unique window through which the intricate spatiotemporal organization of cells can be viewed.Clocks are universal and fundamental to living organisms and are the basis of temporal control of metabolism and behavior (20). The majority of research has focused on the daily clock (circadian clock) that is found in the entire range of organisms from cyanobacteria to humans (6, 9). However, several classes of shorter-period temperature-compensated clocks also exist. Examples of these clocks include the millisecond clock observed during the courtship of Drosophila (19), the 40-s defecation clock (fast clock) found in nematodes (10), and the ultradian clock (period Ϸ 1 h) found in Acanthamoeba castellanii (21) and in Paramecium tetraurelia (15). Biological clocks can be differentiated from biological oscillators and rhythms by two properties: they must run continuously under constant conditions and have temperature compensation (6,20,24) The effects of temperature on the frequencies of biological oscillations have been extensively studied (25, 32). The periods of glycolytic oscillators (4) and cell cycle oscillators (1) are temperature dependent, and the oscillation periods are usually halved when there is a 10°C increase in temperature; i.e., the temperature quotient (Q 10 ) is ϳ2. Such oscillators have no intrinsic timekeeping function, although clocks can drive them (16). Temperature-compensated oscillators have a Q 10 of ϳ1;i.e., there is little alteration in the period when the temperature changes (...

Regulation of yeast oscillatory dynamics

“…Once external noise has been minimized by using the precisely controlled conditions of continuous growth in a fermentor, the culture autosynchronizes physiology, to reveal a temperaturecompensated oscillation (28). In this work we show the coordination of the oscillator includes core transcriptional regulation.…”

“…The metabolite data set used previous work (5,7,12,21,22,25,27,28,37,38), and GC-MS analyses (SI Methods) of intracellular metabolites were used to construct the metabolite data set. All Western blots were carried out according to the manufacturer's instructions (Atto, Bunkyo-ku, Tokyo, Japan).…”

Ultradian oscillators of the circadian clock in <i>Saccharomyces</i> <i>cerevisiae</i>

“…In the presence of bathocuproine (Figure 7(b)), both ENOX1 activities were reduced or eliminated. All that remained were two maxima separated by 40 min which may correspond to the fundamental respiratory oscillation of 40 min normally seen only with continuous cultures [20,21].…”

Circadian gene expression in mammalian fibroblasts revealed by real-time luminescence reporting: Temperature compensation and damping

“…Temperature compensation has sometimes also been observed for ultradian rhythms, but this result is much less common (see ref. 24 for an example). The temperature compensation inherent in Rat-1͞PerLuc cells (Q 10 ϭ 0.85-0.88) lies within the range observed for other circadian clocks and confirms that the daily oscillations of rat-1 cells are regulated by a circadian clock.…”