[Biological safety investigation of the production of human insulin using genetically altered E. coli K-12 cells. 2. Plasmid transfer by mobilization and cointegrate formation under environmental conditions].

Plasmid transfer by mobilization and cointegrate formation was tested with expression plasmids for human insulin in laboratory media and in river water samples. Plasmid pLIZP4 which carries a nic/bom sequence could only be mobilized after cloning of mobilization genes. Plasmid mobilization could be detected in laboratory media only, not in river water samples. The Nic/Bom plasmid pSW3 could be transferred by cointegrate formation in laboratory media at 30 degrees C and 37 degrees C, not at room temperature or in river water. The results allow the conclusion that no transfer of the plasmids pLIZP4 and pSW3 will take place by mobilization or cointegrate formation under environmental conditions.