The growth cycle

On subculturing cells into new vessels they do not start to grow immediately at their maximum rate especially if they are seeded as a 

Some cell types specify, in their name, the procedure required at subculture. Thus 3T3 cells should be split 1 to 3 every 3 days to maintain them in optimal conditions and prevent their ever forming a stationary, confluent culture. 

In suspension, cells may be maintained in exponential growth for long periods, and in theory indefinititely if the cells are grown in a chemostat where the small trickle of incoming nutrients is balanced by the outflow of cell suspension thus maintaining a constant environment and constant cell number. 

More usually a certain volume of cell suspension will be removed every day (or every other day) and replaced with fresh medium. However, in long-term cultures, contamination is a serious hazard and cells in suspension are usually grown in batch cultures which exhibit similar growth kinetics to monolayer cultures. 

In the early work, embryo and tissue extracts were commonly used to encourage growth of cells but now these are only occasionally added to medium and then only for cultivation of certain primary cells (e.g. see 2.2 and 2.3). Today s media, however, as well as containing amino acids, vitamins, salts and glucose normally include serum at about 10% and sometimes also other additives such as Bactopeptone or tryptose phosphate (Appendix 1). 

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It was established that the main amount of polysaccharides was secreted during the logaritmic phase of the growth cycle. 

As these examples show, different defenses among plant parts and seasonal differences have to be considered together. Coffee Coffea arabica) is a well-investigated example of increased chemical defenses when the plant is most vulnerable to herb ivory. The concentration of the alkaloid caffeine (Fig. 11.18) varies between plant parts and with the growth cycle. In the germinating seed, the... 

A characteristic feature of allelopathy is that the inhibitory effects of allelopathic compounds are concentration dependent. Dose-response curves with known compounds show an inhibition threshold. Below this level either no measurable effect occurs, or stimulation may result. Although the concentration of a compound required to exceed the inhibition threshold varies extensively according to different sensitivities among species and also among phases of the growth cycle for higher plants, the concept of an inhibition threshold seems consistent. Thus, it is reasonable to evaluate how, and if, a subthreshold concentration of an allelochemical may contribute to allelopathic interference. Also in need of evaluation is how environmental conditions may influence the deleterious action of an allelochemical and the concentration required for an effect. Such interactions are especially pertinent for those environmental situations that place some degree of stress on plant functions. 

The source material will release excess silicon in the beginning of the growth cycle and be more carbon-rich in the end due to preferential depletion of silicon. This is a known problem and it is a matter of detailed control and an understanding of the dynamic transport mechanisms in combination with thermodynamics. Nevertheless, the result is invariably that SiC boules grown by seeded sublimation growth are Si-rich in the beginning and C-rich near the end, which creates yield issues. Simulation of the process is necessary to improve the situation. 

Desorption from the hydrocarbon is a critical part of the growth cycle of petroleum-degrading bacteria. Petroleum is a mixture of thousands of different hydrocarbon molecules. Any particular bacterium is only able to use a part of the petroleum. As the bacteria multiply at the hydrocarbon/water interface of a droplet, the relative amount of nonutilizable hydrocarbon continually increases, until the cells can no longer grow. For bacteria to continue to multiply, they must be able to... 

The etch cycle is performed at the end of the growth cycle and on new quartz reactors to clean the interior surface of impurities. 

Product Formation It is important to check that the product formed is growth associated. Some products are formed after cell mass reaches the stationary phase of the growth cycle and, therefore, are not growth associated. The evolution of carbon dioxide can be measured and related stoichiometrically to the cell growth. One product that is quite general to many fermentations is the hydrogen ion. The amount of alkali added to the fermentation broth to maintain the pH may be proportional to the growth. 

Stage in the growth cycle when the growth rate is changing. There may be increase or decrease in algal cell mass per unit volume of cell suspension. Volume 1 (6). 

Stage in the growth cycle when the mass of microbial cells doubles over each of the successive and equal time intervals. The doubling time and, therefore, the growth rate during the entire log phase is thus constant. Volume 1(6). 

Carter, B. J. (1990). The growth cycle of adeno-associated vims. In Handbook of Parvoviruses (Tijssen, P., ed.), Vol. 1. CRC Press, Boca Raton, pp. 155-168. 

Effects of chemotherapeutic agents on the growth cycle of mammalian cells. 

Phytotoxins are classical secondary metabolites and as such possess all the characteristics one would expect of such compounds. They are a) structurally heterogeneous, b) contain a variety of functional groups, c) produced by a restricted number of microorganisms, d) produced at specific phases in the growth cycle, e) highly dependent on nutritional and environmental conditions for synthesis and f) not readily metabolized. 

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