Synchronous cultures

NT433 Nishinari, N., and T. Yamaki. Relation between cell division and endogenous auxin in synchronously-cultured tobacco cells. Bot Mag (Tokyo) 1976 89 73. 

The role of calcium in cell division is controversial. The measurement of cation fluxes in synchronized cultures of Tetrahymena shows an influx of calcium 30 minutes prior to the initiation of cell division.440 However, there is also an influx of magnesium, and it has been suggested441 that the fluctuation of these metals during the synchronized division cycle is an effect rather than a cause. 

In the S. cerevisiae synchronous culture, an increased P uptake from the culture medium during DNA synthesis was observed (Gillies et al., 1981). At a high level of external Pi, this uptake provided the necessary phosphorus level in cells and the 31P NMR-visible PolyP remained constant. However, if the external Pi content was low, this PolyP was consumed, acting as a substitute for the phosphate reserve (Gillies et al., 1981). 

I. S. Kulaev, I. A. Krasheninnikov and Yu. A. Tyrsin (1973b). Nucleic acids, polyphosphates and some polyphosphate-metabolizing enzymes in synchronous cultures of Schizosaccharomyces pombe (in Russian). Mikrobiologiya, 38, 613-622. 

G. N. Zaitseva, I. A. Khmel and A. N. Belozersky (1961). Biochemical changes in a synchronous culture of Azotohacter vinelandii (in Russian). Dokl. Akad. Nauk SSSR, 141, 740-743. 

Claquin, P., Kromkamp, J., and Martin-Jezequel, V. (2004). Relationship between photosynthetic metabolism and ceU cycle in a synchronized culture of the marine alga Cylindrotheca fusiformis (BacUlariophyceae). Eur.J. Phycol. 39, 33—41. 

Studies of the mineralization of the larvae of sea urchins (they can be conveniently grown in synchronous culture) have made it possible to utilize molecular biologic techniques to determine gene expression, protein synthesis, and macro-molecular organization as well as the sequences of mineral deposition (Benson et al., 1987). These are some of the earliest forms to be studied and illustrate the connections between genetics and biomineralization. Stem cells responsible for spicule formation can be isolated and produce normal spicules in vitro (Kitajima and Okazaki, 1980) since spines regenerate the secondary mineralization process can also be studied (Ebert, 1967). 

Synchronous cultures of Artemia sp. (brine shrimp) in seawater or rodent or human serum have also been suggested as a screen, with scoring for survival, growth, and morphological and molecular differentiation after exposure directly to agents or to serum from agent-exposed individuals. 

Periodicity approaches have been used for analyzing genes regulated during cell cycles in experiments with synchronized cultures (71, 72). However, these approaches are not generally applicable to nonperiodic data. 

Wanka, F. Geraedts, J. (1972). Effect of temperature in the regulation of DNA synthesis in synchronous cultures of chlorella. Exp. Cell Res. 71, 188-192. 

Nishinari, N. and K. Syono Identification of cytoki-nins associated with mitosis in synchronously cultured tobacco cells Plant Cell Physiol. 21 (1980) 383-393. 

Fig. 25. Time course of population increase in an initially synchronous culture as calculated from Eq. (154).

Synchronized cultures of Chlorella ellipsoidea were used as a model system to identify biochemical modes of action of two herbicides/ butamiphos (0-ethyl--0-(3-methyl-6-nitropheny1)-N-sec-buty1-phosphorothioamidate, formerly coded S-2846), and chlorpropham (isopropyl inch lorocarban il ate). Cell cycle studies showed that butamiphos inhibited cell division, whereas its effects on respiration and general biosynthesis were slight. Confirmatory experiments with onion root apices showed that mitosis was blocked at the metaphase and that the spindle apparatus was disrupted. 

Using a synchronized culture, the effect of butamiphos on cell division was studied (Figure 2). 

In the untreated control, the cell number was constant until cell division started at 18 h and then the cell number increased at an abruptly rapid rate. The total volume of the cell population increased continuously throughout the cell cycle as the individual cells grew in biomass. The average volume per cell gradually increased until cell division started, and then it became abruptly smaller. This pattern is characteristic of a synchronized culture. If butamiphos specifically inhibits the cell division process without affecting other synthetic processes such as respiration and photosynthesis, then the cell number should be constant throughout the cell cycle, the total cell volume of the population should increase continuously (as in the case of the untreated control), and... 

Figure 2. Effect of butamiphos on cell division of Chlorella grown in synchronized culture. Butamiphos in methanol was added to the culture after 6 h. Aliquots were taken for the measurement of cell number and packed cell volume at various time intervals. The dark period was between the 18th and the 24th h. Key O, untreated control and butamiphos-treated (30 /jM).

A comparison of the outcomes of this approach to single-cell protein synthesis kinetics determination with the alternative method which has been widely used in many previous studies of cell cycle and cell kinetic behavior of many organisms is instructive. In the latter methods, synchronous culture or an equivalent experimental technique are used to make measurements of the time variation of protein content or some other cellular variable versus time as the cell grows from a newborn daughter cell to a mature and dividing mother cell. Then, by estimating the slope of... 

M. G. Sargent, Synchronous Culture of B. subtilis Obtained by Filtration with Glass Fibers, J. Bacteriol. 116, 736-740 (1973). 

Atkinson AW Jr, Gunning BES, John PCL SporopoUenin in the cell wall of Chlorella and other algae ultrastmcmre, chemistry, and incorporation of 14C-acetate, studied in synchronous cultures, Planta 107(1) 1—32, 1972. 

Synchronous cultures are used to study the detail of the biochemical... 

An in-vitro nuclear system prepared from HeLa cells, described by Friedman and Mueller (1968), appears to continue the DNA replication process observed in vivo. The system requires intact nuclei, the four deoxyribonucleoside triphosphates, magnesium ion, ATP, and, in addition, a heat-labile cytoplasmic factor. The activity of the system was similar to the DNA synthetic activity observed in intact cells in synchronized culture (Friedman and Mueller, 1968). Cytoplasmic factors also appear to stimulate in-vitro nuclear systems prepared from normal and regenerating rat livers (De Beilis, 1969). The cytoplasmic factors are present in both normal and regenerating liver cytoplasm and stimulate nuclear DNA synthesis in both systems. The stimulation was most marked using regenerating liver factors and normal liver nuclei (De Beilis, 1969). When mouse liver nuclei are recombined with cell free cytoplasmic extracts from mouse ascitic or L-cells active in DNA synthesis there is a marked stimulation of DNA synthesis in the isolated nuclei (Thompson and McCarthy, 1968). Cytoplasmic preparations from HeLa cells also stimulated DNA synthesis in mouse liver nuclei. 

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