Oscillations in protein and RNA content during synchronous growth of <i>Acanthamoeba castellanii</i>

Edwards, Steven W.; Lloyd, David

doi:10.1016/0014-5793(80)81302-0

Cited by 50 publications

(36 citation statements)

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“…During the cell cycle, in each case, the increase in total protein approximated a doubling. That the oscillations observed in synchronously dividing cultures are genuinely associated with the undisturbed cell cycle has already been established (2,4) and is confirmed in Fig. 3.…”

Section: Resultssupporting

confidence: 64%

“…The phase relationships between oscillatory components suggest that the concentration of ADP is the key factor controlling this process of in vivo respiratory control (2). Furthermore, total cellular protein content oscillates approximately in phase with respiration, so that tight coupling between energy demand and its supply occurs via the adenine nucleotide system (4).…”

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confidence: 99%

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Temperature-compensated oscillations in respiration and cellular protein content in synchronous cultures of Acanthamoeba castellanii.

Lloyd¹,

Edwards²,

Fry³

1982

Proc. Natl. Acad. Sci. U.S.A.

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Synchronous cultures of the soil amoeba Acanthamoeba castellanii, established by a selection procedure, show significant oscillations ofrespiration and total cell protein. There was little difference between the period of these oscillations, which averaged 76 min, although the five incubation temperatures used varied between 200C and 300C and the cell division time increased from 7.8 to 16 hr. The phase ofthese oscillations also corresponded approximately at all incubation temperatures. Similar observations made over the whole division cycle at three temperatures indicated that similar oscillations occurred, with a constant period of 65 min, although these data were too variable to show this unequivocally. Control (asynchronous) cultures show that the oscillations are not a consequence of metabolic perturbation produced by the centrifugal selection procedure. It is suggested that these temperature-compensated epigenetic oscillations serve a dual role in cell cycle and circadian timekeeping and that cell cycle time is quantized.We have shown, in minimally perturbed synchronous cultures established by a simple and rapid selection procedure (1), that the respiration of the soil amoeba Acanthamoeba castellanii ocsillates during the cell division cycle with a period of -1 hr and a mean amplitude (peak-trough) of oe30% (2). Thus, at 30TC, seven respiratory subcycles occur in a cell cycle time of 7.8 hr. Measurements of adenine nucleotide pools (2), redox state of mitochondrial flavoproteins (3), and effects ofinhibitors of electron transport and an uncoupler of energy conservation (2) indicate that the respiratory oscillation involves cycles of energization and deenergization of mitochondria. The phase relationships between oscillatory components suggest that the concentration of ADP is the key factor controlling this process of in vivo respiratory control (2). Furthermore, total cellular protein content oscillates approximately in phase with respiration, so that tight coupling between energy demand and its supply occurs via the adenine nucleotide system (4).Processes that occur in living organisms can be classified on the basis oftheir characteristic relaxation times (5, 6). Those that involve metabolic intermediates have half-times of the order of minutes ("metabolic time domain") whereas those particularly associated with cellular growth in eukaryotes often have halftimes of the order of hours ("epigenetic time domain"). The upper limit of the epigenetic domain corresponds to the cell cycle time, and epigenetic processes include biosynthesis of macromolecules and their processing, transport, and interaction [i.e., the consequences of gene expression and altered activities of genes (6)]. We have suggested that the phase relationships and time scales of the oscillations observed here place 0

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Section: Resultssupporting

confidence: 64%

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confidence: 99%

Temperature-compensated oscillations in respiration and cellular protein content in synchronous cultures of Acanthamoeba castellanii.

Lloyd¹,

Edwards²,

Fry³

1982

Proc. Natl. Acad. Sci. U.S.A.

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“…Inhibition by acetaldehyde must also occur, but not at the low concentrations ( 0n75 mM) monitored during continuous culture (50 % inhibition requires 100 mM and its maximum accumulation corresponds to maximum respiration). Unlike the oscillatory respiratory metabolism studied in A. castellanii , 1980Lloyd et al, 1982a) or Schizosaccharomyces pombe (Poole et al, 1973), that of Sacch. cerevisiae reported here is not directly coupled to the cell division cycle, i.e.…”

Section: Lloyd and Othersmentioning

confidence: 91%

“…Thus the succession of events during respiratory oscillation in yeast is similar to that previously described in the soil amoeba Acanthamoeba castellanii Lloyd et al, 1982a, b) where it was concluded that the phenomenon represents in vivo mitochondrial respiratory control (ADP-acceptor control ; Chance & Williams, 1956). The slow kinetics indicates that, as in the amoeba, the cycle of mitochondrial changes in yeast is responding to a slowly changing energetic demand of biosynthetic processes (Edwards & Lloyd, 1980 ;Lloyd et al, 1981), i.e. that it is controlled by an ultradian clock (Lloyd & Edwards, 1984, 1987.…”

Section: Lloyd and Othersmentioning

confidence: 99%

Cycles of mitochondrial energization driven by the ultradian clock in a continuous culture of Saccharomyces cerevisiae

et al. 2002

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A continuous culture of Saccharomyces cerevisiae IFO 0233, growing with glucose as the major carbon and energy source, shows oscillations of respiration with a period of 48 min. Samples taken at maxima and minima indicate that (i) periodic changes do not occur as a result of carbon depletion, (ii) intrinsic differences in respiratory activity occur in washed organisms and (iii) a respiratory inhibitor accumulates during respiratory oscillations. Plasma membrane and inner mitochondrial membranes generate transmembrane electrochemical potentials ; changes in these can be respectively assessed using anionic or cationic fluorophores. Thus flow cytometric analyses indicated that an oxonol dye [DiBAC 4 (3) ; bis(1,3-dibutylbarbituric acid)trimethine oxonol] was excluded from yeasts to a similar extent (in S98 % of the population) at all stages, showing that the plasma membrane potential was maintained at a steady value. However, uptake of Rhodamine 123 was greatest at that phase characterized by a low respiratory rate. Addition of uncouplers of energy conservation [CCCP (m-chlorocarbonylcyanide phenylhydrazone) or S-13 (5-chloro-3-t-butyl-2-chloro-4 1 -nitrosalicylanilide)] to the continuous cultures increased the respiration, but had only a transient effect on the period of the oscillation. Electron microscopy showed changes in mitochondrial ultrastructure during the respiratory oscillation. At low respiration the cristae were more clearly defined due to swelling of the matrix ; this corresponds to the ' orthodox ' conformation. When respiration was high the mitochondrial configuration was ' condensed '. It has been shown previously that a temperature-compensated ultradian clock operates in S. cerevisiae. It is proposed that mitochondria undergo cycles of energization in response to energetic demands driven by this ultradian clock output.

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“…In eukaryotes, DNA replication is restricted to a discrete portion of the cell cycle, the S phase, whereas total RNA and protein are generally considered to be continuously synthesized. Recently, however, evidence has been obtained for discontinuous accumulation of macromolecules and oscillatory expression of respiratory activity during the cell cycles of various eukaryotic micro-organisms (Edwards & Lloyd, 1980;Lloyd et al, 1981).…”

Section: Introductionmentioning

confidence: 99%

The Cell Cycle of the Budding Yeast Sterigmatomyces halophilus: Culture Fractionation by Zonal Centrifugation and the Accumulation of DNA, RNA and Protein

Salmon¹,

Poole²

1983

Microbiology

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Sterigmatomyces halophilus is an unusual budding yeast in which daughter cells are formed, remote from the mother cell, on fine projections called sterigmata. Some fundamental properties of the cell cycle have been explored by separating cells from an exponentially growing culture into size, and thus age, classes by density-gradient centrifugation. Rate separations on high capacity, high resolution, equivolumetric gradients of sucrose, or, alternatively, isopycnic separations on gradients of Urografin revealed consistent and reproducible patterns of accumulation of DNA, RNA and protein through the cell cycle. Total DNA accumulation was stepwise, synthesis occurring late in the cycle, whilst protein accumulated continuously with no evidence for the discontinuities reported in some other lower eukaryotes. Total RNA accumulation, measured either colorimetrically or by long-term incorporation of radioactively-labelled uracil was transiently elevated early in the cycle and then accumulated continuously. A mathematical analysis of the volume distributions of the cells in fractions from the gradients showed that there is a hyperbolic relationship between cell age and size but that, to a first approximation, measurements of cell size (and density) are direct measures of age. The results are discussed with reference to (1) the unusually high buoyant density of this yeast, (2) the resolution of zonal cell separation methods and (3) macromolecular accumulation in the cell cycles of other eukaryotic micro-organisms.

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Oscillations in protein and RNA content during synchronous growth of Acanthamoeba castellanii

Cited by 50 publications

References 22 publications

Temperature-compensated oscillations in respiration and cellular protein content in synchronous cultures of Acanthamoeba castellanii.

Temperature-compensated oscillations in respiration and cellular protein content in synchronous cultures of Acanthamoeba castellanii.

Cycles of mitochondrial energization driven by the ultradian clock in a continuous culture of Saccharomyces cerevisiae

The Cell Cycle of the Budding Yeast Sterigmatomyces halophilus: Culture Fractionation by Zonal Centrifugation and the Accumulation of DNA, RNA and Protein

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