Synchronized growth

The bacterial culture converts a portion of the supplied nutrient into vegetative cells, spores, crystalline protein toxin, soluble toxins, exoenzymes, and metabolic excretion products by the time of complete sporulation of the population. Although synchronous growth is not necessary, nearly simultaneous sporulation of the entire population is desired in order to obtain a uniform product. Depending on the manner of recovery of active material for the product, it will contain the insolubles including bacterial spores, crystals, cellular debris, and residual medium ingredients plus any soluble materials which may be carried with the fluid constituents. Diluents, vehicles, stickers, and chemical protectants, as the individual formulation procedure may dictate, are then added to the harvested fermentation products. The materials are used experimentally and commercially as dusts, wettable powders, and sprayable liquid formulations. Thus, a... 

It is often difficult to avoid introducing some degree of synchronous growth in a culture simply as a results of routine operations. Thus Stubblefield et al. (1967) found that subculture of Don-C cells every 24 h exerted a selection pressure favouring cells with a 12 h generation time and highest mitotic frequencies at about 7 and 19 h. 

Figure 8.14 Changes in the content of nucleic acids, phospholipids, Pi and PolyPs, and the activities of exopolyphosphatase (PolyPase) and pyrophosphatase (PPase) during synchronous growth of Schizosaccharomyces pombe (Kulaev et al., 1973b) (a) 1, number of cells PL, phospholipids OP, P J P, total phosphate (b) PPi, acid-soluble polyphosphate PP2, salt-soluble polyphosphate (c) PP3, alkali-soluble polyphosphate PP4, hot-perchloric-acid-soluble polyphosphate JZPolyP, total polyphosphate.

A. L. Baker and R. R. Schmidt (1963). Intracellular distribution of phosphorus during synchronous growth of Chlorella pyrenoidosa. Biochim. Biophys. Acta, 74, 75-83. 

R. R. Schmidt (1966). Intracellular control of enzyme synthesis and activity during synchronous growth of Chlorella. In I. L. Cameron and G. M. Padilla (Eds), Cell Synchrony Studies in Biosynthetic Regulation, Academic Press, New York, pp. 189-198. 

Leon, C., Kumazawa, S., and Mitsui, A. (1986). Cyclic appearance of aerobic nitrogenase activity during synchronous growth of unicellular cyanobacteria. Curr. Microbiol. 13, 149—153. 

As a test of the range of applicability of the kinetics determined in the steady-state measurements, the transient population balance equation has been solved, using the kinetics determined from steady state, to simulate the sequence of protein content frequency functions obtained in synchronous growth of this organism. The simulation results are in very good qualitative agreement with the experimental measurements of the corresponding quantities (28). 

The study of synchronized growth may well be of value in understanding the events during fermentation where the stationary phase cells used as an inoculum tend to reproduce in a synchronous manner in the early stages of fermentation. 

Scherbaum and his associates have made many comparisons of normal and synchronized growth of Tetrahymena, essentially by chemical analysis. Out of these have come the propositions that synchronization of cell division by heat shocks should be referred to changes in DNA metabolism (Scherbaum et al., 1959), to altered concentration of DPN and TPN in the cells (Scherbaum, 1960), and to destruction of messenger RNA (Byfield and Scherbaum, 1967). What needs to be pointed out here is that each of the last two proposals, if and when found compelling, can be fitted to our views. 

Non-synchronous growth Natural pattern of growth during the log phase in which every cell in a culture divides at some point during the generation time, but not simultaneously. 

Mayhew, E., 1969, Effect of ribonuclease and neuraminidase on the electrophoretic mobility of tissue culture cells in para synchronous growth, /. Cell. Physiol. 69 311-320. 

Senger, H, Bishop NI (1971) Changes in fluorescence and absorbance during synchronous growth of Scenedesmus,Proc.Int.Congr.Photosynth., 2nd,677-687. 

Zeuthen Dr. Pardee, you have made the distinction between synchronous and synchronized growth. But why do you take such a fairly strong stand that to get... 

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