Changing patterns of 32P and 33P utilization in cells of Candida utilis during the cell cycle

1972 ◽  
Vol 18 (11) ◽  
pp. 1691-1693 ◽  
Author(s):  
P. S. S. Dawson ◽  
H. Glättli
Keyword(s):  
Cell Cycle ◽  
Doubling Time ◽  
Candida Utilis ◽  
Cold Water ◽  
Growth Conditions ◽  
Changing Patterns ◽  
Rna And Dna ◽  
Synchronized Cultures ◽  
In Cells

Incorporation of 33P and 32P into different fractions of continuous phased (synchronized) cultures of Candida utilis was studied. Two different growth conditions (on C-limited and N-limited media) were used at a doubling time of 6 h. Incorporation of 33P and 32P into four fractions (lipid, cold-water ex-tractable, RNA and DNA) showed a variable, nonuniform, behavior during the cell cycle. Different patterns of incorporation between cells on the two media were observed.

Changes in phosphorus composition of Candida utilis during the cell cycle and postcycle period

1971 ◽  
Vol 17 (3) ◽  
pp. 339-345 ◽  
Author(s):  
H. Glättli ◽  
P. S. S. Dawson
Keyword(s):  
Cell Cycle ◽  
Candida Utilis ◽  
Phosphorus Content ◽  
Cold Water ◽  
Carbon Limitation ◽  
Cycle Period ◽  
Phosphorus Fraction ◽  
Extractable P ◽  
Rna And Dna ◽  
Water Extractable

Cells of Candida utilis were grown under carbon limitation in phased culture at a doubling time of 4 h. The phosphorus contents of four (lipid, cold water extractable, RNA, and DNA) fractions, obtained empirically by serial extraction of the cells, were determined at [Formula: see text]-h intervals during the cell cycle and post-cycle periods. The results showed that the phosphorus composition of the cells was changing throughout both cell cycle and postcycle periods.Each phosphorus fraction doubled during the cell cycle; for the major fractions (cold water extractable P and RNA-P) this occurred as a gradual increase spread over the cell cycle period, but for the minor fractions (lipid-P and DNA-P) the increase was restricted to the latter half of the cell cycle period. Expressed as proportions of the total phosphorus content, the phosphorus contents of the major fractions remained constant, but the minor ones changed during the cell cycle. Other, different, changes were observed between the various fractions during the postcycle period.

scholarly journals Large-scale selection synchrony of Tetrahymena thermophila

1986 ◽  
Vol 84 (1) ◽  
pp. 237-251
Author(s):  
R.J. Hill ◽  
T. Kroft ◽  
M. Zuker ◽  
I.C. Smith
Keyword(s):  
Cell Cycle ◽  
Cell Culture ◽  
Cell Population ◽  
Large Scale ◽  
Doubling Time ◽  
Tetrahymena Thermophila ◽  
Growth Conditions ◽  
Scale Selection

A method is described, based on the phagocytosis of colloidal ferrite particles, which gives highly synchronous populations of Tetrahymena thermophila. To ensure a successful synchrony, the cell culture doubling time, the limits of the phagocytic period and the distribution of cell stages must first be determined. Once these parameters are known, synchrony can be achieved under a variety of growth conditions and with cultures ranging in volume from a few millilitres to 12 litres or more. The main advantages of the method are that the apparatus required is simple, large volumes of cells can be handled easily, and the synchronous populations can be prepared within a few hours. In principle, the method should be applicable to any cell population in which phagocytosis occurs discontinuously over the cell cycle.

Stimulation by pH of cell cycle initiation in the yeast Candida utilis

1981 ◽  
Vol 59 (11) ◽  
pp. 2043-2048 ◽  
Author(s):  
K. Chandapillai Thomas
Keyword(s):  
Cell Cycle ◽  
Nitrogen Source ◽  
Growth Medium ◽  
Respiratory Quotient ◽  
Doubling Time ◽  
Candida Utilis ◽  
Cellular Processes ◽  
Ph Shift ◽  
Bud Emergence ◽  
Limiting Nutrient

The effect of shifting pH of the growth medium on cell cycle initiation by the yeast Candida utilis was studied. The yeast was grown by the phased method of cultivation with nitrogen source (ammonium) in growth limiting concentrations and with a phasing period (imposed doubling time) of 6 h. The pH of the culture during the phased growth was maintained between 2.0 and 2.1. The rate of cell cycle initiation as determined by the rate of bud emergence was 24% per hour. If the pH of the culture was shifted to 6.0 at the beginning of the phasing period and maintained at that level for the rest of the phasing period the rate of bud emergence increased to 50% per hour. The increased rate of bud emergence was accompanied by a fast uptake of oxygen and the growth-limiting nutrient and by a reduction in the respiratory quotient. The results suggest that the pH shift accelerated cellular processes necessary for cell cycle initiation.

Inhibition of Cell Division by High External NaCl Concentrations in Synchronized Cultures of Chlorella emersonii

1982 ◽  
Vol 9 (2) ◽  
pp. 179 ◽  
Author(s):  
T.L Setter ◽  
H Greenway ◽  
J Kuo
Keyword(s):  
Electron Microscopy ◽  
Cell Division ◽  
Dna Synthesis ◽  
Dna Content ◽  
Cell Cycles ◽  
Daughter Cells ◽  
Specific Effects ◽  
Rna And Dna ◽  
Synchronized Cultures ◽  
In Cells

Effects of high external NaCl concentrations on growth were examined in the unicellular freshwater alga Cldorella emevsonii during different phases of cell development, using synchronized cultures obtained by alternating light-dark cycles. Growth of cultures synchronized at 1 mM NaCl [external osmotic pressure (next=) 0.08 MPa] was compared with (i) cultures synchronized at 200 mM NaCl (n,,, = 1.01 MPa) and (ii) cultures synchronized at 1 mM NaCl from which the daughter cells were suddenly transferred to 100, 150 or 200 mM NaCl. The effects of these two treatments on synthesis of protein, RNA and DNA during cell cycles were similar, and are attributed to the high nexta nd not to specific effects of Na+ and C1-. Growth inhibitions in cells at 200 mM NaCl relative to 1 mM NaCl occurred mainly via effects on cell division; this was confirmed by electron microscopy. There was a lag before net DNA synthesis commenced, and there were reductions in rates of net DNA synthesis in cells at 200 mM NaCl relative to 1 mM NaC1. Rates of increase in cell volume and in protein and RNA content per cell were little affected by high external NaCl concentrations. Consequently, daughter cells at 200 mM NaCl were approximately twice the volume and contained twice as much protein and RNA as daughter cells at 1 mM NaCl, while DNA content was equal in daughter cells at 1 and 200 mM NaCl.

Cell cycle and post cycle changes during continuous phased growth of Candida utilis

1970 ◽  
Vol 16 (8) ◽  
pp. 783-795 ◽  
Author(s):  
P. S. S. Dawson
Keyword(s):  
Cell Cycle ◽  
Candida Utilis ◽  
Culture Method ◽  
Limited Growth ◽  
Cell Cycles ◽  
Carbon And Nitrogen ◽  
Primary And Secondary Metabolism ◽  
Cell Components ◽  
Changing Patterns ◽  
Quantitative Changes

A modification of the continuous phased culture method is described. This permits examination of changes taking place during the cell cycle (cell cycle changes) to be extended into the following period (postcycle changes).Candida utilis was grown on a glucose medium under conditions of carbon and nitrogen limitation. In nitrogen-limited growth, the size of the amino acid pool changed between the cell cycle and postcycle, but remained relatively constant for both periods in carbon-limited growth. In carbon-limited growth, the carbohydrate composition of the cells was relatively little changed, but considerable changes occurred in nitrogen-limited cells during cell cycle and postcycle periods. Changing patterns in phospholipid contents were also observed during cell cycles and postcycles of both carbon- and nitrogen-limited growths.Qualitative and quantitative changes in various cell components were related to the nutrient limiting to growth and the pattern of its use by the cells. The results illustrate the influence of environmental change upon the cell and are discussed in relation to aspects of primary and secondary metabolism in the cell.

The oxygen uptake of phased yeast cultures growing at different doubling times on nitrogen- and energy-limited media

1968 ◽  
Vol 14 (10) ◽  
pp. 1127-1131 ◽  
Author(s):  
J. Müller ◽  
P. S. S. Dawson
Keyword(s):  
Energy Source ◽  
Cell Cycle ◽  
Oxygen Uptake ◽  
Doubling Time ◽  
Candida Utilis ◽  
Limited Growth ◽  
Yeast Cultures ◽  
Limiting Nutrient ◽  
Source Limitation ◽  
Doubling Times

The oxygen uptake of Candida utilis growing in phased culture at doubling times of 4, 6, 8, and 12 hours was measured under conditions of nitrogen and energy source limitation. No abrupt doubling of oxygen uptake was observed at any stage of the cell cycle. The pattern of oxygen uptake was closely related to the assimilation of the growth-limiting nutrient. In nitrogen-limited growth, the specific oxygen uptake (Qo2) was found to decrease as the doubling time increased, but, in glucose-limited growth, no change was observed.

Growth, cell cultivation, cell metabolism, and the cell cycle of Candida utilis as explored by continuous phased culture

1985 ◽  
Vol 31 (3) ◽  
pp. 183-189 ◽  
Author(s):  
P. S. S. Dawson
Keyword(s):  
Cell Cycle ◽  
Growth Rate ◽  
Doubling Time ◽  
Microbial Growth ◽  
Candida Utilis ◽  
Cell Metabolism ◽  
Growth Theory ◽  
Cell Cultivation ◽  
Phenotypic Changes ◽  
Nitrogen Phosphorus

The problem of microbial growth, centred both on the population and the cell, and studied largely in batch culture, is also accessible by open methods of continuous culture which release such growth studies from restrictions imposed by the traditional methods. Thus, continuous phased (synchrony) culture enables studies of the cell cycle to be conducted systematically under different conditions of nutrient limitation and growth rate, and allows the phenotypic changes of chemostat steady states to be expressed as patterns of "cell cycle" behaviour over the doubling time. Studies conducted with Candida utilis in this way, in carbon-, nitrogen-, phosphorus-, and other nutrient-limited growths, have revealed a variable behaviour in the cell cycle, especially in the G1 period. Such variability in cell cycle behaviour is closely linked to the nutrient control of growth in the culture and generally accords with the Monod growth theory. Such variable behaviours for the cell are examined and assessed in relation to leading contemporary models for the cell cycle.

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