Carbon dioxide evolution during the cell cycle of the fission yeast Schizosaccharomyces pombe

1978 ◽  
Vol 33 (1) ◽  
pp. 385-397
Author(s):  
J. Creanor
Keyword(s):  
Cell Cycle ◽  
Dna Synthesis ◽  
Schizosaccharomyces Pombe ◽  
Fission Yeast ◽  
Nuclear Division ◽  
Complete Medium ◽  
Co2 Evolution ◽  
Carbon Dioxide Evolution ◽  
Synchronous Cultures ◽  
Constant Addition

The rate of CO2 evolution was measured in synchronous cultures of the fission yeast Schizosaccharomyces pombe growing in a minimal medium. The rate of CO2 evolution was found to double sharply at about the time of nuclear division (0.75 of the way through the cell cycle). For the remainder of the cell cycle the rate remained constant. Addition of inhibitors of DNA synthesis or nuclear division did not affect the pattern of CO2 evolution in synchronous cultures. Similarly, in an induced synchronous culture, in which DNA synthesis, nuclear division and cell division—but not growth, were synchronized, CO2 evolution showed a continuous pattern and not the step-wise increase associated with the normal synchronous cultures. When S. pombe was grown in a complete medium, the evolution of CO2 in a synchronous cultures was shown to increase in a continuous manner but at a rate faster than the growth of the culture.

Oxygen uptake during the cell cycle of the fission yeast Schizosaccharomyces pombe

1978 ◽  
Vol 33 (1) ◽  
pp. 399-411
Author(s):  
J. Creanor
Keyword(s):  
Cell Cycle ◽  
Cell Division ◽  
Oxygen Uptake ◽  
Dna Synthesis ◽  
Schizosaccharomyces Pombe ◽  
Fission Yeast ◽  
Nuclear Division ◽  
Synchronous Culture ◽  
Synchronous Cultures ◽  
The Many

Oxygen uptake was measured in synchronous cultures of the fission yeast Schizosaccharomyces pombe. The rate of oxygen uptake was found to increase in a step-wise manner at the beginning of the cycle and again in the middle of the cycle. The increases in rate were such that overall, oxygen uptake doubled in rate once per cell cycle. Addition of inhibitors of DNA synthesis or nuclear division to a synchronous culture did not affect the uptake of oxygen. In an induced synchronous culture, in which DNA synthesis, cell division, and nuclear division, but not ‘growth’ were synchronized, oxygen uptake increased continuously in rate and did not show the step-wise rises which were shown in the selection-synchronized culture. These results were compared with previous measurements of oxygen uptake in yeast and an explanation is suggested for the many different patterns which have been reported.

Protein synthesis and its relation to the DNA-division cycle in the fission yeast Schizosaccharomyces pombe

1984 ◽  
Vol 69 (1) ◽  
pp. 199-210
Author(s):  
J. Creanor ◽  
J.M. Mitchison
Keyword(s):  
Cell Cycle ◽  
Protein Synthesis ◽  
Schizosaccharomyces Pombe ◽  
Protein Content ◽  
Fission Yeast ◽  
Nuclear Division ◽  
Restrictive Temperature ◽  
Tentative Conclusion ◽  
Synchronous Cultures

The rate of protein synthesis has been measured with pulse labels of [3H]tryptophan in synchronous and asynchronous cultures of cdc mutants of Schizosaccharomyces pombe shifted up to the restrictive temperature. The cell cycle related fluctuations in rate that occur in normal synchronous cultures vanish when nuclear division is blocked in synchronous cultures of cdc2 and cdc10. But they persist in cdc11 where nuclear division continues and cleavage is stopped. We conclude that nuclear division affects the rate of synthesis and that this effect is inhibitory and probably persists for the last 40% of the cycle. When nuclear division has been blocked, the rate of synthesis continues to increase until a plateau is reached where the rate remains constant. Three size mutants of cdc2 reach the plateau at the same average protein content per cell although their initial protein contents vary over a threefold range. Comparison of these results with those from cdc10 leads to the tentative conclusion that the plateau starts when the cells reach a critical protein/DNA ratio.

The Effect of 2-Phenyl Ethanol on the DNA Synthesis Cycle of Schizosaccharomyces Pombe

1970 ◽  
Vol 7 (2) ◽  
pp. 523-530
Author(s):  
C. J. BOSTOCK
Keyword(s):  
Cell Cycle ◽  
Dna Synthesis ◽  
Schizosaccharomyces Pombe ◽  
Normal Growth ◽  
S Phase ◽  
G1 Phase ◽  
Synchronous Cultures ◽  
Number Of Cells

The effect of different concentrations of 2-phenyl ethanol (PE) on growth and DNA synthesis of Schizosaccharomyces pombe is described. o.3% PE inhibits the entry of cells into S phase, but allows a doubling in the number of cells in the culture. The effect of o.2% PE on random and synchronous cultures of S. pombe shows that, in the continued presence of the inhibitor, the S phase is moved to a different point in the cell cycle. Cells continue to grow in the presence of o.2% PE with a G1 phase occupying a significant portion of the cell cycle. This differs from normal growth when the G1 phase is absent.

Rates of synthesis of polyadenylated messenger RNA and ribosomal RNA during the cell cycle of Schizosaccharomyces pombe. With an appendix: calculation of the pattern of protein accumulation from observed changes in the rate of messenger RNA synthesis

1976 ◽  
Vol 21 (3) ◽  
pp. 497-521
Author(s):  
R.S. Fraser ◽  
F. Moreno
Keyword(s):  
Cell Cycle ◽  
Dna Synthesis ◽  
Schizosaccharomyces Pombe ◽  
Ribosomal Rna ◽  
Messenger Rna ◽  
Rna Synthesis ◽  
Protein Accumulation ◽  
Synchronous Culture ◽  
Synchronous Cultures ◽  
Gene Copies

The rates of polyadenylated messenger RNA and ribosomal RNA synthesis were measured in synchronously dividing cultures of fission yeast (Schizosaccharomyces pombe). Control asynchronous cultures, which had been exposed to the conditions used for preparing synchronous cultures, were investigated to check for effects of the synchronization procedure itself on RNA synthesis. After each period of DNA synthesis in synchronous culture, the rates of messenger and ribosomal RNA synthesis doubled, suggesting that gene number controls the rate of messenger and ribosomal RNA synthesis. This was confirmed by experiments with asynchronous, exponential-phase cultures in which DNA synthesis was inhibited by hydroxyurea. Both synchronous culture and hydroxyurea experiments suggested that there is a delay of 15 min (0-1 of the cell generation time) between replication of the DNA and transcription of both gene copies. A pattern of protein accumulation was calculated from changes in the rate of polyadenylated messenger RNA synthesis during synchronous culture. The simulated pattern indicates that protein is accumulated linearly, with a doubling in the rate of accumulation once per cell cycle. The simulated pattern of protein accumulation is very similar to measurements previously reported by other workers of changes in activities of 3 enzymes in synchronous cultures. It is suggested that the doubling of the rate of messenger RNA synthesis, as a consequence of the replication of the DNA once per cycle, provides the basis of a mechanism for control of the doubling of other cellular constituents during the cell cycle.

Arginase and sucrase potential in the fission yeast Schizosaccharomyces pombe

1980 ◽  
Vol 46 (1) ◽  
pp. 399-431
Author(s):  
T. Benitez ◽  
P. Nurse ◽  
J.M. Mitchison
Keyword(s):  
Dna Replication ◽  
Dna Synthesis ◽  
Schizosaccharomyces Pombe ◽  
Fission Yeast ◽  
Gene Dosage ◽  
Critical Ratio ◽  
Restrictive Temperature ◽  
Wild Type ◽  
Synchronous Cultures ◽  
Short Period

The induction potentials of 2 enzymes, sucrase and arginase, have been measured in asynchronous and synchronous cultures of the fission yeast Schizosaccharomyces pombe. The effect on potential of inhibiting DNA synthesis is asynchronous cultures has been studied using 2 temperature-sensitive dcd mutants, one blocked in DNA replication and the other blocked in mitosis. The results show that despite inhibition of DNA synthesis, sucrase and arginase potential both continue to increase exponentially for at least a generation of growth after shifting the cdc mutants from the permissive to the restrictive temperature. A second method of inhibiting DNA synthesis, using deoxyadenosine, has also been tested. Cells treated with deoxyadenosine stop the increase in potential for a short period. However, experiments carried out using a cdc mutant together with deoxyadenosine show that the block to the increase in potential is due to a side effect of the inhibitor. It appears that increase in potential is not dependent upon continued DNA replication, and that gene dosage does not control potential in the normal cell cycle. This conclusion is supported by measurements on mutants of different cell sizes. potential is proportional to size (protein content per cell is asynchronous culture) and not to DNA content. Although potential is not gene limited in normal cells, it does appear to be so in the abnormally large cells produced by a cdc block. If cdc mutants of different sizes are grown asynchronously, and DNA synthesis is inhibited by a shift to the restrictive temperature, there is no increase in potential. This critical ratio is different for the 2 enzymes, but for each enzyme it is similar in all the mutants tested. When large cells (produced by a mutant block for 4.5 h) are shifted down in temperature, there are synchronous rounds of DNA synthesis and division and also step doublings in potential. In synchronous cultures of wild type cells, both enzymes show a stepwise doubling of potential at 0.2 of a cycle after DNA replication. In synchronous cultures of cdc mutants blocked either in replication or in mitosis, the potential steps continue with the normal timing observed in wild type cells. This shows that the steps are not dependent on the events of the DNA-division cycle but are controlled by another mechanism. Attainment of a critical size might be part of this mechanism, but tests with size mutants argue against this.

scholarly journals The effect of CO2 on the timing of cell cycle events in fission yeast Schizosaccharomyces pombe

1988 ◽  
Vol 89 (3) ◽  
pp. 433-439
Author(s):  
B. NOVÁK ◽  
J. HALBAUER ◽  
E. LÁSZLÓ
Keyword(s):  
Cell Cycle ◽  
Growth Rate ◽  
Schizosaccharomyces Pombe ◽  
Fission Yeast ◽  
Co2 Production ◽  
Complete Medium ◽  
Co2 Removal ◽  
Wild Type ◽  
In The Wild ◽  
G2 Phase

The effect of CO2 removal on the cell cycle phases of Schizosaccharomyces pombe has been examinedin minimal, aspartate-containing and complete medium. The removal of CO2 shortened the G2 phase of the cell cycle and arrested the cells in G1 phase in minimal medium. The G1 block caused by CO2 deprivation was demonstrated by transition-point and flow-cytometry analyses. The slow-down of anapleurotic CO2 fixation might be responsible for this effect, as aspartic acid could abolish the G1 block. The shortening of G2 phase in the wild-type cells was observed in every medium irrespective of whether the growth rate was changed or not. The experiments in which growth rate was not changed by CO2 shift-down suggest that this CO2 effect can be independent from its action on CO2-fixing steps in metabolism. Therefore we propose that CO2 inhibits mitosis infission yeast and we explain the proportionality between growth rate and cell size at mitosis found by Fantes & Nurse by this CO2 inhibition. The larger CO2 production in fast-growing cells leads to a higher CO2 concentration, which could exerta stronger inhibition of mitosis. A wee mutant, which has lost its mitotic size control, also shows the G1 block after CO2 deprivation, but its mitosis is insensitive to CO2. Comparing the respiration of wee and wild-type cells we conclude that CO2 inhibits the citric acid cycle in the wild type. The consequence of these results in the regulation of fission yeast cell cycle is discussed.

scholarly journals Mitochondrial adenosine triphosphatase of the fission yeast, Schizosaccharomyces pombe 972h−. Changes in activity and oligomycin-sensitivity during the cell cycle of catabolite-repressed and -de-repressed cells

1977 ◽  
Vol 162 (1) ◽  
pp. 39-46 ◽  
Author(s):  
S W Edwards ◽  
D Lloyd
Keyword(s):  
Cell Cycle ◽  
Atpase Activity ◽  
Schizosaccharomyces Pombe ◽  
Fission Yeast ◽  
Adenosine Triphosphatase ◽  
Total Activity ◽  
Stages Of Growth ◽  
Synchronous Cultures ◽  
A Cell ◽  
In Cells

1. Changes in activity of ATPase (adenosine triphosphatase) during the cell cycle of Schizosaccharomyces pombe were analysed in cell-free extracts of cells harvested from different stages of growth of synchronous cultures and also after cell-cycle fractionation. 2. Oligomycin-sensitive ATPase oscillates in both glucose-repressed synchronous cultures and shows four maxima of activity approximately equally spaced through the cell cycle. The amplitude of the oscillations accounts for between 13 and 80% of the total activity at different times in the cell cycle. 3. Oligomycin sensitivity varies over a fourfold range at different stages of the cell cycle. 4. The periodicity of maximum oligomycin sensitivity is one-quarter of a cell cycle. 5. These results were confirmed for the first three-quarters of the cell cycle by cell-cycle fractionation. 6. In cells growing synchronously with glycerol, ATPase activity increases in a stepwise pattern, with two steps per cell cycle; the first of these occurs at 0.54 of the cell cycle and the second at 0.95. 7. These results are discussed in relation to previously obtained data on the development of mitochondrial activities during the cell cycle.

Changes in the rate of oxygen consumption in synchronous cultures of the fission yeast Schizosaccharomyces pombe

1990 ◽  
Vol 96 (3) ◽  
pp. 429-433
Author(s):  
B. Novak ◽  
J.M. Mitchison
Keyword(s):  
Cell Cycle ◽  
Oxygen Consumption ◽  
Oxygen Uptake ◽  
Schizosaccharomyces Pombe ◽  
Fission Yeast ◽  
Oxygen Electrode ◽  
Co2 Production ◽  
Synchronous Cultures ◽  
Rate Of Oxygen Consumption

Oxygen consumption was measured with an oxygen electrode in synchronous cultures of S. pombe. There were changes during the cell cycle in the rate of oxygen uptake, which are most clearly shown as oscillations in acceleration curves (rate of the rate of uptake). Under various conditions of selection and induction synchrony the acceleration curves are similar to those found earlier for CO2 production. As with CO2 production, the oscillations continued after a block to the DNA-division cycle. There were, however, two differences between oxygen uptake and CO2 production. The oxygen oscillations were more marked and also were out of phase by half a cycle. The respiratory coefficient therefore changes through the cycle.

The Schizosaccharomyces pombe hus5 gene encodes a ubiquitin conjugating enzyme required for normal mitosis

1995 ◽  
Vol 108 (2) ◽  
pp. 475-486 ◽  
Author(s):  
F. al-Khodairy ◽  
T. Enoch ◽  
I.M. Hagan ◽  
A.M. Carr
Keyword(s):  
Cell Cycle ◽  
Dna Synthesis ◽  
Schizosaccharomyces Pombe ◽  
Cell Cycle Control ◽  
S Phase ◽  
Temperature Sensitive ◽  
Checkpoint Control ◽  
Ubiquitin Conjugating Enzyme ◽  
Efficient Recovery ◽  
Mediate Cell

Normal eukaryotic cells do not enter mitosis unless DNA is fully replicated and repaired. Controls called ‘checkpoints’, mediate cell cycle arrest in response to unreplicated or damaged DNA. Two independent Schizosaccharomyces pombe mutant screens, both of which aimed to isolate new elements involved in checkpoint controls, have identified alleles of the hus5+ gene that are abnormally sensitive to both inhibitors of DNA synthesis and to ionizing radiation. We have cloned and sequenced the hus5+ gene. It is a novel member of the E2 family of ubiquitin conjugating enzymes (UBCs). To understand the role of hus5+ in cell cycle control we have characterized the phenotypes of the hus5 mutants and the hus5 gene disruption. We find that, whilst the mutants are sensitive to inhibitors of DNA synthesis and to irradiation, this is not due to an inability to undergo mitotic arrest. Thus, the hus5+ gene product is not directly involved in checkpoint control. However, in common with a large class of previously characterized checkpoint genes, it is required for efficient recovery from DNA damage or S-phase arrest and manifests a rapid death phenotype in combination with a temperature sensitive S phase and late S/G2 phase cdc mutants. In addition, hus5 deletion mutants are severely impaired in growth and exhibit high levels of abortive mitoses, suggesting a role for hus5+ in chromosome segregation. We conclude that this novel UBC enzyme plays multiple roles and is virtually essential for cell proliferation.

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