Synchronization, cell

By the early 1960s it was clear that simple experiments on P uptake were inadequate to distinguish different species of RNA in mixed populations of cells at different stages of the cell cycle. The future for labeling experiments with 32P in cell biology was to lie mainly with synchronized cells and for studies on nucleic acids, with molecular biological techniques. 

Isotopic experiments on the cell cycle could also be performed with ordinary (non-autoradiographic) biochemical procedures if synchronized cells were available. The earliest animal preparation providing such a system for use in vivo was the regenerating rat liver. Stowell (1949) and Abercrombie and Harkness (1951) noted that DNA synthesis in livers... 

This classification of anticancer drugs has inherent limitations. For instance, it may be difficult to generalize about the phase specificity of a particular drug, since this may vary among cell types. Several techniques are available to synchronize cell populations in such a way that most cells will be in the same phase of the cell cycle. After synchronization, one can treat cells in each phase and determine their relative sensitivity to drugs throughout the cell cycle. 

Perillyl alcohol induced apoptosis and was more effective than perillaldehyde at inhibiting the proliferation of human carcinoma cell lines cultured in vitro [319]. Perillyl alcohol treatments suppressed cell growth [313-315], reduced cyclin D1 RNA and protein levels and prevented the formation of active cyclin D1 associated with kinase complexes in synchronous cells during the exit of GO and entry into the cell cycle [284, 316, 317]. In addition, perillyl alcohol treatment induced an increased association of p21 [316-318] with cyclin E-Gdk2 complexes, inhibited the activating phosphorylation of Gdk2 [312, 316, 318-320], initiated apoptosis [321-324] and suppressed small G-protein isoprenylation... 

For certain aspects of work with cell cultures, a useful property of tunicamycin is that it can be used to synchronize cell division. After release of the block imposed hv the drug, the cloning efficiency was also higher, and the cloning size more regular, than in the control culture.547... 

An analysis of different stages can be made by fixing cells at different times after treatment, when the cells appear at metaphase, where the chromosomes can be analyzed. With synchronous cells, treatment at different times after initiation of synchronization permits cells in different stages of the cycle to be treated. 

When the HU synchronization period was finished, and the HU was removed, the seedlings were immediately incubated with 1 mM BOA or water (controls), and the cell cycle was analyzed at different times. Samples (nuclear suspensions) are prepared from root meristems and analyzed by flow cytometry every 2 h during a time period of 12-14 h.15 Comparison of the synchronized-cell cycle progression of BOA-treated plants with that of the corresponding controls allows for detection of partial or total inhibition of the cell cycle. 

Fraser, R.S.S., Studies on messenger and ribosomal RNA synthesis in plant tissue cultures induced to undergo synchronous cell division, Eur. J. Biochem., 50, 529-537, 1975. 

I. Sundberg and M. Nilshammer-Holmvall (1975). The diurnal variation in phosphate uptake and ATP level in relation to deposition of starch, lipid and polyphosphate in synchronized cells of... 

Anti-glycating effects. It was shown in 1990 that camosine (50-100 mg/kg body weight) increases survival of rodents when it was administered to animals before sub-lethal dose of y-irradiation [5]. Kurella et al. [58] have found that under these conditions viability of haemopoietic stem cells is significantly increased and their colony forming activity is activated as well. These phenomena can be addressed to anti-radical protection of biomacromolecules by camosine, however camosine was additionally found to protect nuclear DNA from oxidative modification induced by hyperoxia, to preserve its native stmcture and to synchronize cell cycle in vitro [59]. Its addition to the medium where fibroblasts were cultivated increased the longevity of cell life and reversed the senescence features of the cells [60]. Moreover, camosine was demonstrated to increase stability of... 

Scherbaum, O., and Zeuthen, E. (1954). Induction of synchronous cell division in mass cultures of Tetrahymena piriformis. Exp. Cell Res. 6, 221-227. 

Biochemical studies require the preparation of cell extracts from many cells. For biochemical studies of the cell cycle, the eggs and early embryos of amphibians and marine invertebrates are particularly suitable. In these organisms, multiple synchronous cell cycles follow fertilization of a large egg. By isolating large numbers of eggs from females and... 

Synchronizing Cell Cultures - Laborotory procedure of manipulating cells to bring all of the them to the same phase of the cell cycle. It is accomplished by a thymidine block. 

Thymidine Block - Mechanism for synchronizing cells in which thymidine is added to cells to inhibit DNA synthesis. This prevents passage of the cells from the G1 to S phase of the cell cycle. Subsequent transfer of cells to a medium lacking thymidine reverses the inhibition and allows them to initiate DNA synthesis synchronously. 

In CML, HU largely has been replaced by imatinib. HU has produced anecdotal, temporary remissions in patients with advanced cancers (e.g., head and neck or genitourinary carcinomas, melanoma). HU has been incorporated into several schedules with concurrent irradiation, as it can synchronize cells into a radiation-sensitive phase of the cell cycle. 

This was possible to detect because the monoculture of Thalassiosira rotula employed showed partly synchronized cell divisions during exponential growth. Brockmann et al. [137] carried out combined measurements of dissolved amino acids and carbohydrates. Glucose and lysine occurred in highest concentrations. Mague et al., [22] found that extracellular production of free amino acids counted for 7.1% of the of the total extracellular C released in an exponentially growing culture of S. costatum Myklestad et al., [26] measured 10.7% for C. affinis or 3.6% when calculated as percent of total incorporated cell N. In contrast to this Admiraal et al., [139] found that none of three benthic diatoms released more than 0.1 % of the cellular N as free amino acids and concluded that benthic diatoms may act as net consumers of amino acids. Several authors did measure both intracellular and extracellular concentrations of many amino acids [22 140 -142]. The clear difference in relative composition of intracellular and extracellular fractions as pointed out by the first mentioned of these authors, show that the released pool is not just a portion of the intact cells content. 

The observation that ribonucleotide reductase activity always reflects the proliferative capacity of cells and organisms can be substantiated in synchronous cell cultures. Activity... 

Studies of cells have shown large changes as the moves through its life cycle. DEP studies have shown differences in response with changing colony age. These studies have shown the importance of using synchronized cells so that all cells are the same age. 

Friedman, D. L., and G. C. Mueller. 1968. A nuclear system for DNA replication from synchronized cells. Biochim. Biophys. Acta, 161 455468. 

Gold, M., and C. W. Helleiner. 1964. Deoxyribonucleic acid polymerase in L cells. 1, Properties of the enzyme and its activity in synchronized cell cultures. Biochim. Biophys. Acta, 80 193-203. 

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