Variation in the Ratios and Concentrations of Nucleotide Triphosphates and Udp-Sugars During a Perfused Batch Cultivation of Hybridoma Cells

Ryll, Thomas; Jäger, Volker; Wagner, Roland

doi:10.1007/978-94-011-3550-4_36

Cited by 6 publications

(1 citation statement)

References 9 publications

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“…Since no data for histidine concentration were available between days 25 and 32, the apparent maximal histidine consumption rate in relation to day 24 is shown. recently found that the energy charge of mammalian cells in vitro did not change and was maintained at a very high level of over 0.95 during the growth cycle, even under extreme nutrient limitation (Ryll et al, 1991). Furthermore, the enzymatic degradation of threonine requires the presence of N6,IPO-methylenetetrahydrofolate, which is oxidated during methyl transfer to glycine.…”

Section: Resultsmentioning

confidence: 99%

Cultivation of recombinant baby hamster kidney cells in a fluidized bed bioreactor system with porous borosilicate glass

Kratje¹,

Reimann²,

Hammer³

et al. 1994

Biotechnol. Prog.

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Dense cell cultivation of the recombinant cell line BHK 21 pSVIL2 was performed in a fluidized bed bioreactor system containing porous borosilicate glass carriers. Experiments were carried out with different medium formulations for a period of 48 days. Due to an effective immobilization of the cells in the reactor, continuous operation was easy to perform. Maximal cell densities and product yields could be maintained, even when protein-free medium was perfused exceeding 2 reactor volumes per day. Final cell densities of magnitude 7.1 x 10(7) mL-1 intrasphere volume were reached, while the interleukin-2 production rate was 0.70 mg day-1. The cell specific productivity reached a value of 1.3 x 10(-10) mg day-1. The first results were presented with a cell line that grows under glutamine-free medium conditions. The use of a glutamine-free medium for the cultivation of the cells resulted in a drastic decrease in cell metabolism. Furthermore, the amino acids lysine and histidine were produced and secreted into the culture supernatant, although these metabolites normally are considered to be essential for animal cells grown in vitro. However, no lethal effect on the cells has been detected, and the total number of cells in the reactor remained constant. The metabolism of threonine has been detected to be directly dependent on the presence of glutamine. Cells grown in glutamine-free culture medium produced glycine yields 6 times higher than those grown in glutamine-containing medium. A bead-to-bead transfer of the cells has also been detected when the cells immobilized within the intrasphere volume of the borosilicate carriers reached the stationary phase.

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Section: Resultsmentioning

confidence: 99%