Cell growth kinetics

Effect of Temperature on Insect Cell Growth Kinetics... 

Ennaoui, A. Weber, M. Saad, M. Harneit, W. Lux-Steiner, M. Ch. Karg, F. 2000. Chemical bath deposited Zn(Se,OH)x on Cu(In,Ga)(S,Se)2 for high efficiency thin film solar cells Growth kinetics, electronic properties, device performance and loss analysis. Thin Solid Films 361-362 450 153. 

The subject of biochemical reactions is very broad, covering both cellular and enzymatic processes. While there are some similarities between enzyme kinetics and the kinetics of cell growth, cell-growth kinetics tend to be much more complex, and are subject to regulation by a wide variety of external agents. The enzymatic production of a species via enzymes in cells is inherently a complex, coupled process, affected by the activity of the enzyme, the quantity of the enzyme, and the quantity and viability of the available cells. In this chapter, we focus solely on the kinetics of enzyme reactions, without considering the source of the enzyme or other cellular processes. For our purpose, we consider the enzyme to be readily available in a relatively pure form, off the shelf, as many enzymes are. 

The most reasonable approach for addressing this dilemma is to exploit differences in cell growth kinetics between cancer cells and host cells. A hallmark of cancerous cell growth is the rapidity of its cellular proliferation. At any given time, a malignant tumor should have more cells undergoing mitosis and replication than other tissues in the host. 

Because this class of functions has been used extensively to model cell growth kinetics, these functions can be modified to describe subpopulations of cells. The equations below describe a Gompertz growth model that has been modified to allow cells to oscillate between a therapeutically sensitive state (Rs) and a resistant state (Rr). The same modification can also be made to the simple growth model (28). 

Galban, C. J. and B. R. Locke. 1999. Analysis of cell growth kinetics and substrate diffusion in a polymer scaffold. Biotechnol Bioeng 65 121-132. 

These two approximations form limits on the rate of substrate utilization by the biofilm when we consider a reasonable range of constants for cell growth kinetics and biofilm densities. To use these results, we must therefore examine what typical values we might obtain for these constants. 

Product formation kinetics in mammalian cells has been studied extensively for hybridomas. Most monoclonal antibodies are produced at an enhanced rate during the Gq phase of the cell cycle (8—10). A model for antibody production based on this cell cycle dependence and traditional Monod kinetics for cell growth has been proposed (11). However, it is not clear if this cell cycle dependence carries over to recombinant CHO cells. In fact it has been reported that dihydrofolate reductase, the gene for which is co-amplified with the gene for the recombinant protein in CHO cells, synthesis is associated with the S phase of the cell cycle (12). Hence it is possible that the product formation kinetics in recombinant CHO cells is different from that of hybridomas. 

Monod kinetics Kinetics of microbial cell growth as a function of substrate concentration proposed by Jacques Monod and widely used to understand growth-substrate relationships. 

For type 3 processes, growth and metabolic activity reach a maximum early in the batch process cycle (Figure 3.1) and it is not until a later stage, when oxidative activity is low, that maximum desired product formation occurs. The stoichiometric descriptions for both type 3 and 4 processes depend upon the particular substrates and products involved. In the main, product formation in these processes is completely uncoupled from cell growth and dictated by kinetic regulation and activity of cells. 

Table 3.1 shows the kinetic parameters for cell growth, rate models with or without inhibition and mass transfer coefficient calculation at various acetate concentrations in the culture media. The Monod constant value, KM, in the liquid phase depends on some parameters such as temperature, initial concentration of the carbon source, presence of trace metals, vitamin B solution, light intensity and agitation speeds. The initial acetate concentrations in the liquid phase reflected the value of the Monod constants, Kp and Kp. The average value for maximum specific growth rate (/xm) was 0.01 h. The value... 

The kinetic of cell growth for prediction of growth rate is projected by the net growth rate, which is ... 

The parameters of the Monod cell growth model are needed i.e. the maximum specific growth rate and the Michaelis-Menten constant are required for a suitable rate equation. Based on the data presented in Tables 10.1 and 10.2, obtain kinetic parameters for... 

A limiting case of Monod kinetics has Ks = 0 so that cell growth is zero order with respect to substrate concentration. Rework Example 12.7 for this situation, but do remember to stop cell growth when S = 0. Compare your results for X and p with those of Example 12.7. Make the comparison at the end of the exponential phase. 

Regnlar arrays of platinnm were achieved by chemical reduction of a platinnm salt that had been deposited onto the S-layer of Sporosarcina ureae [132]. This S-layer exhibits sqnare lattice symmetry with a lattice constant of 13.2 nm. Transmission electron microscopy revealed the formation of well-separated metal clusters with an average diameter of 1.9 nm. Seven clnster sites per nnit cell were observed. UV-VIS spectrometry was nsed to study the growth kinetics of the clnsters. 

A very versatile piece of equipment that is affordable for individual laboratories is the microplate reader. This allows multiple samples to be analyzed at once, commonly in a 96-well format, although 384- and 1536-well formats are available. Typical measurements that can be performed include UV-Vis absorbance, fluorescence, or luminescence, allowing a range of assays to be performed, such as cell growth, enzyme kinetics, enzyme stability, or enzyme-linked immunosorbent assay [60-62]. Functionality can be increased by the use of liquid dispensing systems or automatic plate handling. 

Shirai, Y., Yamaguchi, M., Kobayashi, A., Nishi, A., Nakamura, H., and Murakami, H., Change in Growth Kinetics of Hybridoma Cells Entrapped in Collagen Gel Affected by Alkaline Supply, Cytotechnol., 14 129 (1994)... 

The kinetics of cell growth/death under free and/or immobilized states assume a relevant role in the assessment of the amount of biophase present in the reactor. Obviously, the kinetics depends strongly on the carbon/energy source available in wastewaters or purposely added. With the exception of consortia collected from anaerobic digesters, single strain cultures used in azo-dye conversion are characterized by hindered growth under anaerobic conditions [26, 29, 41], For these biosystems, the duration of the anaerobic stage must be carefully monitored to preserve cell viability. 

The growth rate of cells is taken proportional to the cell concentration, x, and to an empirical form of the dependence on the concentration, p, of the nutrient. That empirical form was assumed by Monod (1942) to be the same as in the Michaelis-Mewnten model for enzyme kinetics. This makes the rate of cell growth,... 

Kovarova-Kovar, K. and Egli, T. (1998). Growth kinetics of suspended microbial cells from single-substrate-controlled growth to mixed-substrate kinetics, Microbiol. Mol. Biol. Rev., 62, 646-666. 

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