ISSN:
0006-3592
Keywords:
recombinant bacterium
;
plasmid loss
;
modeling
;
Escherichia coli
;
Chemistry
;
Biochemistry and Biotechnology
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Biology
,
Process Engineering, Biotechnology, Nutrition Technology
Notes:
A large number of models concerning cultures of genetically engineered bacteria have been described. Among them, some are specifically adapted to continuous cultures and lead to the determination of two variables: (i) the difference in the specific growth rates between plasmid-carrying cell and plasmid-free cells (δμ) and (ii) the frequency of plasmid loss by plasmid-containing cells (prμ+). Until now, studies have been performed on the global expression prμ+ and δμ, whose value during continuous assays have been supposed approximately constant (mean value) and not on separate values of both terms pr and μ+, respectively, probability of plasmid loss and specific growth rate of the plasmid-carrying cells. So far these studies do not allow examination of the relationship between these two last parameters. Experimental results were obtained with Escherichia coli C600 galk (GAPDH), a genetically engineered strain that synthetizes an elevated quantity of glyceraldehyde-3-phosphate dehydrogenase (GAPDH). From data obtained during continuous cultures, it is shown that during an assay, δμ, and prμ+ do not remain constant. An appropriate mathematical analysis of the expression of μ- (specific growth rate of the plasmid-free cells) and μ+ has been built up. This allows the evaluation of the values of μ+ and μ- during the continuous cultures carried out at different dilution rates. Values of pr have been calculated from these data. Indeed our results show that pr increases with μ+. A modeling approach which allows correct simulation of this variation is also proposed. This model is derived from the Hill equation regarding cooperative binding of enzymic type reaction. © 1993 John Wiley & Sons, Inc.
Additional Material:
9 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/bit.260410402
Permalink
