[Change in regulation of catabolite-dependent lux-operon, cloned in a recombinant plasmid, under the effect of environmental factors].

Expression of the lux-genes cloned on the recombinant plasmid pPHL7 (AprLux+) in Escherichia coli z905 cells was studied in various environments, including model aquatic ecosystems. Expression of the lux-genes strongly depended on the nutritional status of the medium. In particular, the cultivation of cells in nutrient-rich medium favored the maintenance of the initial level of expression of the lux-operon, whereas nutrient limitation induced recombinant cell variants with an impaired control of the catabolite-dependent lux-operon.

[Regulated expression of bacterial luminescence genes cloned in a multicopy recombinant plasmid].

Luminescence and growth responses of the recombinant strain Escherichia coli Z905 (AprLux+) to different concentrations of ampicillin depended on the source of carbon and energy. When glycerol was used as the substrate, the intensity of luminescence rose with the ampicillin concentration in the medium. Glucose caused catabolite repression of cell luminescence up to the late stationary phase, and ampicillin enhanced this effect.