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  • Electronic Resource  (103)
  • 1985-1989
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  • 1970  (103)
  • Biochemistry and Biotechnology  (73)
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  • Electronic Resource  (103)
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  • 1985-1989
  • 1980-1984
  • 1970-1974  (103)
  • 1955-1959
  • 1850-1859
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  • 101
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: In replicated 30 to 40-ml suspension cultures of rapidly proliferating monkey kidney cells of a comparatively fragile strain, the rates of glucose utilization and lactic acid accumulation averaged about 400 micrograms and 110 micrograms per 106 cells per day respectively, with average molar La/Gl ratios of 0.48. These two rates of glucose utilization and lactic acid accumulation were about 4 × and 10 × as high as the corresponding rates in comparable cultures of the hardier strain 2071-L mouse fibroblasts under the same conditions, with average molar La/Gl ratios of 0.16. In comparable but nonproliferating suspension cultures of the same strain of monkey kidney cells, during about 3 weeks the rates were extremely high, with about 710 micrograms glucose utilized and 445 micrograms lactic acid accumulated per 106 cells per day, with average molar La/Gl ratios of 1.37. The rates of glucose uptake and lactic acid accumulation were higher in the nonproliferating cultures aerated with 5% CO2 in air than in those aerated with 10% CO2 in air. This difference was associated with pH, which was higher in the former group.It was concluded that with this fragile strain of monkey Kidney cells(1) in nonproliferating cultures the cells were metabolizing actively but with a marked tendency to higher La/Gl ratios, (2) in the proliferating cultures the high rates of glucose utilization and lactic acid accumulation were definitely not directly correlated with the rate of growth, and (3) in none of the cultures was the amount of glucose remaining in the fluid at fluid changes so low as to have been a limiting factor.Information in the literature concering glucose utilization and lactic acid production by cells vitro is voluminous and in some respects contradictory. In the present study the rates were unexpectedly high for the monkey kidney cells, particularly those in the otherwise apparently inactive nonproliferating cultures. The data seem to be unique, in that an established strain of cells in chemically defined medium in suspension cultures has been characterized for these metabolic parameters in both proliferating cultures and in equivalent nonproliferating cultures under directly comparable conditions.The concept was developed that since these monkey kidney cells are obviously more fragile than the other cells examined, the complex physical stresses imposed upon these cells in agitated cultures can be modified and lessened in order to permit growth. Lessening of such mechanical stress waa brought about in several ways, of which only the smaller flask size seemed to be at least partly effective. Increasing either the concentration or the viscosity type of Methocel waa not effective.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
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  • 102
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 12 (1970), S. 561-575 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The stability characteristics of a continuous culture system were studied following the addition of the natural product inhibitor, ethanol. For a steady state culture of Klebsiella (Aerobacter) aerogenes there was a linear dependence of growth rate on ethanol concentration. Following impulse and step addition of the inhibitor, response patterns of the growth rate (μ) and overall metabolism (Qo2, QCo2, QAC) were observed. A mathematical model of the transient behavior of a product-limited system is proposed, and analog computer solutions fitted to the experimental data. The transient response of the growth rate could best be described by second or higher order equations, e.g., \documentclass{article}\pagestyle{empty}\begin{document}$$ T_2^2 \frac{{d^2 \mu }}{{dt^2 }} + 2T_2^2 \xi \frac{{d\mu }}{{dt}} + \mu = \mu _m (1.0 - q.P_t) $$\end{document} with values of the second order time constant (T2) = 5 min, and damping coefficient (ξ) = 0.4.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
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  • 103
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Fungal cells from Curvularia lunata were entrapped in a crosslinked polyacrylamide gel. The gel-cells obtained as granules were applied in the microbial transformation of Reichstein compound S leading to cortisol through an 11-β-hydroxylation step. Some kinetic studies of this conversion using gel-cells were carried out. In addition, it was shown that gel-cell granules which had lost part of their 11-β-hydroxylase activity on storage could be reactivated yielding preparations with increased activity.From Corynebacterium simplex a steroid dehydrogenase catalyzing the Δ1- dehydrogenation of cortisol leading to prednisolone was isolated and partially purified. The preparation was entrapped in a crosslinked polyacrylamide gel and the gel-enzyme granules obtained used in steroid dehydrogenation processes.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
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