Adaptation of Escherichia coli growth rates to the presence of pBR322.
Changes in the growth rate of Escherichia coli K12 J62-1 in response to the presence of plasmid pBR322 have been investigated. Plasmid-free and plasmid-containing strains were grown in batch culture and their maximum specific growth rate (mu max) determined. The acquisition of pBR322 by the host resulted in a decreased mu max. Following repeated subculturing of the plasmid-containing strain on selective medium, restoration in mu max was observed. The copy number and structure of the plasmid were not significantly altered during the experiment. Growth rate measurements for a series of strains constructed using a combination of host cells and plasmids with and without culture histories, indicated that the site of the adaptive mutation was located on the host chromosome rather than on the plasmid.
McDermott
P J
PJ
Biology Division, School of Sciences, Staffordshire University, Stoke-on-Trent, UK.
Gowland
P
P
Gowland
P C
PC
D000222:Adaptation, Physiological / Q000502:physiology; D004926:Escherichia coli / Q000235:genetics / Q000254:growth & development*; D010957:Plasmids / Q000378:metabolism*