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.

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.

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.

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.

scholarly journals Metabolic Control of Cell Elongation and Cell Division in Bacillus subtilis

2021 ◽  
Vol 12 ◽  
Author(s):  
Anne Galinier ◽  
Elodie Foulquier ◽  
Frédérique Pompeo
Keyword(s):  
Cell Cycle ◽  
Bacillus Subtilis ◽  
Cell Division ◽  
Cell Elongation ◽  
Bacterial Cell ◽  
Doubling Time ◽  
Control Cell ◽  
Cellular Processes ◽  
Nutritional Conditions ◽  
Bacterial Cell Cycle

To survive and adapt to changing nutritional conditions, bacteria must rapidly modulate cell cycle processes, such as doubling time or cell size. Recent data have revealed that cellular metabolism is a central regulator of bacterial cell cycle. Indeed, proteins that can sense precursors or metabolites or enzymes, in addition to their enzymatic activities involved in metabolism, were shown to directly control cell cycle processes in response to changes in nutrient levels. Here we focus on cell elongation and cell division in the Gram-positive rod-shaped bacterium Bacillus subtilis and we report evidences linking these two cellular processes to environmental nutritional availability and thus metabolic cellular status.

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.

scholarly journals VERSATILE ROLE OF AUXIN AND ITS CROSSTALK WITH OTHER PLANT HORMONES TO REGULATE PLANT GROWTH AND DEVELOPMENT

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Hammad Ishtiaq ◽  
Savita Bhardwaj ◽  
Aaliya Ashraf ◽  
Dhriti Kapoor
Keyword(s):  
Cell Cycle ◽  
Plant Growth ◽  
Plant Growth Regulators ◽  
Growth Regulators ◽  
Plant Hormones ◽  
Growth And Development ◽  
Naphthalene Acetic Acid ◽  
Plant Growth And Development ◽  
Indole Butyric Acid ◽  
Cellular Processes

Plant growth regulators are significant chemical compounds which are synthesized inside the plant cells and play vital role in plant growth and development. Such compounds are usually active at very low concentrations. These plant growth regulators act as a signalling molecule, which influences the growth of plants. Throughout the previous year’s remarkable investigation have been done for understanding the synthesis of auxin and its effect on various physiological progressions. Auxin is a plant hormone that is involved in various physiological activities, including basic cellular processes such as cell enlargement, regulation of the cell cycle and distinction progress. Plants and several other microorganisms together produce auxin in order to carry out their cell cycle. The chemically synthesized auxins like NAA (naphthalene acetic acid) and IBA (Indole- butyric acid), also take part in various cellular processes. Against various types of biotic and abiotic stress conditions, these plant hormones significantly contribute in promoting acclimatization and adaptation in combination with other phytohormones. The present review highlights some of the important features of auxin role in regulation of plant growth either alone or in crosstalk with other plant hormones.

scholarly journals The Interaction of the Gammaherpesvirus 68 orf73 Protein with Cellular BET Proteins Affects the Activation of Cell Cycle Promoters

2009 ◽  
Vol 83 (9) ◽  
pp. 4423-4434 ◽  
Author(s):  
Matthias Ottinger ◽  
Daniel Pliquet ◽  
Thomas Christalla ◽  
Ronald Frank ◽  
James P. Stewart ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Binding Site ◽  
Transcriptional Activation ◽  
Activation Function ◽  
Murine Gammaherpesvirus ◽  
Cellular Processes ◽  
Interaction Sites ◽  
Gammaherpesvirus 68 ◽  
Bet Protein

ABSTRACT Infection of mice with murine gammaherpesvirus 68 (MHV-68) provides a valuable animal model for gamma-2 herpesvirus (rhadinovirus) infection and pathogenesis. The MHV-68 orf73 protein has been shown to be required for the establishment of viral latency in vivo. This study describes a novel transcriptional activation function of the MHV-68 orf73 protein and identifies the cellular bromodomain containing BET proteins Brd2/RING3, Brd3/ORFX, and BRD4 as interaction partners for the MHV-68 orf73 protein. BET protein members are known to interact with acetylated histones, and Brd2 and Brd4 have been implicated in fundamental cellular processes, including cell cycle regulation and transcriptional regulation. Using MHV-68 orf73 peptide array assays, we identified Brd2 and Brd4 interaction sites in the orf73 protein. Mutation of one binding site led to a loss of the interaction with Brd2/4 but not the retinoblastoma protein Rb, to impaired chromatin association, and to a decreased ability to activate the BET-responsive cyclin D1, D2, and E promoters. The results therefore pinpoint the binding site for Brd2/4 in a rhadinoviral orf73 protein and suggest that the recruitment of a member of the BET protein family allows the MHV-68 orf73 protein to activate the promoters of G1/S cyclins. These findings point to parallels between the transcriptional activator functions of rhadinoviral orf73 proteins and papillomavirus E2 proteins.

scholarly journals Changes in numbers of prolactin receptors during the cell cycle of Nb2 cells

1998 ◽  
Vol 159 (1) ◽  
pp. R1-R4
Author(s):  
IG Camarillo ◽  
JA Rillema
Keyword(s):  
Cell Cycle ◽  
Specific Binding ◽  
Prolactin Receptors ◽  
Initial Value ◽  
Cellular Processes ◽  
Nb2 Cells ◽  
Signalling Molecule ◽  
Lactogenic Hormones ◽  
T Lymphoma ◽  
Stimulation Of

Lactogenic hormones including prolactin (PRL) have mitogenic effects on Nb2 cells, a pre-T lymphoma cell line. Previous studies have characterized the PRL stimulation of cellular processes such as RNA/DNA synthesis, signalling molecule activation, and the expression of specific genes. The data presented here explores the fluctuations in plasma membrane PRL receptor (PRLR) number that occur in the Nb2 cells during the course of a 24 h cell cycle. PRLR abundance was determined by measuring specific binding of [I125] oPRL to G1 arrested-intact Nb2 cells in which the cell cycle was initiated by addition of nonradioactive oPRL. Preliminary studies revealed that 1 ng/ml oPRL was the minimum PRL concentration that causes a maximal stimulation of mitogenesis, without interfering with [I125] oPRL binding measurements. Subsequent experiments revealed that upon cell cycle initiation of G1 arrested Nb2 cells with 1 ng/ml oPRL, PRLR number remained constant for the initial 6 h. After 8 h PRLR numbers decreased and at 12 h, the PRLR number was less than 25% of the initial value. After 12 hr, PRLR numbers increased and reach initial values by 18 hr. These studies show that the expression of cell surface PRL receptors is modulated in a sequential fashion during the cell cycle of Nb2 cells.

P21 is a flexible, multi-functional protein. It governs various tumor cell activities, including autophagy. p21 is a possible radiotherapy target

2021 ◽  
Author(s):  
Moataz Dowaidar
Keyword(s):  
Cell Cycle ◽  
Dna Repair ◽  
Tumor Microenvironment ◽  
Tumor Cell ◽  
Radiation Exposure ◽  
Future Study ◽  
Regulatory Role ◽  
Post Translational Modification ◽  
Functional Protein ◽  
Cellular Processes

p21 is a versatile protein with a lot of different functions. P21 controls several cellular processes in the tumor, including cell cycle, DNA repair, apoptosis, senescence, autophagy, and the tumor microenvironment, in response to radiation exposure. The fact that it is engaged in both of these processes makes things much more puzzling. As a result, truly grasping p21 continues to be a challenge. Researchers have begun to pay attention to p21 and consider it a potential radiotherapeutic target because of its robust regulatory role. The methods by which p21 performs contradictory tasks should be the focus of future study, as well as how to control its oncogenicity selectively. In biological systems, p21 can play a range of roles according to its many post-translational modification sites. The ability to strike a balance between p21's many functions might be the secret to successful radiotherapy.

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