Evaluation of the E. coli ribosomal rrnB P1 promoter and phage-derived lysis genes for the use in a biological containment system: a concept study.

A concept study devised for the development of a biological containment system has been conducted. We show that the lysis genes of different phage origin function in a variety of bacteria. They may therefore be suited for conditional suicide cassettes. Moreover, we tested whether the Escherichia coli rrnB P1 promoter could function as an environmentally responsive element sensing poor growth conditions expected after an accidental release of E. coli production strains from a bioreactor. Mimicking poor nutrient conditions by production of the alarmone guanosine tetraphosphate (ppGpp) with a plasmid encoded ppGpp synthetase I, the rrnB P1 promoter activity was completely turned off. These experiments suggested that the rrnB P1 promoter may be used as an efficient biosensor for altered growth conditions. A concept for a conditional suicide system employing the rrnB P1 promoter and phage-derived lysis genes as key components is discussed.