[The effect of growth rate and culturing conditions on the stability of plasmid pCJ55 and on the level of expression of a large fragment of DNA-polymerase I, cloned in Escherichia coli].

Plasmid pCJ55 with a cloned gene for the large fragment of Escherichia coli DNA polymerase I is stable in the population of a recombinant strain under the conditions of batch and continuous cultivation at different dilution rates in the presence of ampicillin. The level of Klenow fragment expression is determined by at least two factors: the stability of the recombinant strain and its specific growth rate. The maximal activity of the Klenow fragment was found after thermoinduction of the culture growing at a rate of mu = 0.6 h-1 in a synthetic medium with bactopeptone and glucose as a carbon source.