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Amplification of different ColEl plasmids in an Escherichia coli relA strain
Author(s) -
Schroeter A.,
Riethdorf S.,
Hecker M.
Publication year - 1988
Publication title -
journal of basic microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.58
H-Index - 54
eISSN - 1521-4028
pISSN - 0233-111X
DOI - 10.1002/jobm.3620280818
Subject(s) - plasmid , strain (injury) , biology , microbiology and biotechnology , genetics , gene , anatomy
Amino acid starved cells of an E. coli relA strain accumulate a large amount of pBR322 plasmid DNA. In this study ColEl related plasmids of different copy number and size including a high copy number plasmid mutant of pBR322 were amplified in a relA strain of E. coli K‐12 under amino acid limitation in order to determine the upper plasmid level in amino acid starved cells. In all cases we measured a 4 to 6 fold increase of the plasmid copy number in comparison to log‐phase cells independent of the size, the number of origins per plasmid molecule or the copy number in log‐phase cells. The plasmid copy number in amino acid starved cells varies from about 200 (pBR322‐dimer) to about 2000 (high copy number plasmid pERIII‐BPL4, see B OROS et al. 1986). Rop + and rop − plasmids show the same amplification rate under the used conditions.