PMID: 807914May 1, 1975

Plasmid-determined tetracycline resistance in Streptococcus faecalis: evidence for gene amplification during growth in presence of tetracycline

Proceedings of the National Academy of Sciences of the United States of America
Don B ClewellB Bauer

Abstract

The tetracycline (TG)-resistant Streptococcus faecalis strain DS-5Cl harbors two plasmids designated alpha and gamma with molecular masses of approximately 6 and 35 million daltons, respectively. TC-sensitive variants were derived by storing cells at 45 degrees for 2-3 weeks. Analysis of covalently closed circular DNA from five such variants (derived independently) revealed that in each variant the alpha-plasmid, which normally sediments at 28 S (supercoiled) in a sucrose density gradient, was replaced by a 22S substance. Growth of DS-5Cl in the presence of 150 mug/ml of TC (minimum inhibitory concentration is 250 mug/ml in liquid broth) for a prolonged period of time (50-60 generations) resulted in the disappearance of 28S DNA and the appearance of a heterogeneous covalently-closed circular DNA sedimenting at about 40-48 S. This phenomenon was accompanied by an increase in the level of bacterial TC-resistance, whereby tells were subsequently grown in the absence of TC for 70-80 generations, the heterogeneous DNA disappeared and a typical 28S alpha-plasmid reappeared. The cells also became less resistant to TC, i.e., the minimum inhibitory concentration returned to 250 mug/ml. These data suggest that bacterial growth in the pre...Continue Reading

Citations

Jan 10, 1979·Molecular & General Genetics : MGG·R MattesR Schmitt
Feb 1, 1990·European Journal of Clinical Microbiology & Infectious Diseases : Official Publication of the European Society of Clinical Microbiology·Don B Clewell
Jul 18, 2009·Nature Reviews. Microbiology·Linus Sandegren, Dan I Andersson
Jun 1, 1977·Proceedings of the National Academy of Sciences of the United States of America·D Perlman, R Stickgold
Apr 1, 1983·Proceedings of the National Academy of Sciences of the United States of America·P J YoungmanR Losick
Aug 1, 1976·Antimicrobial Agents and Chemotherapy·J R Tagg, L W Wannamaker
Aug 19, 2009·Annual Review of Genetics·Dan I Andersson, Diarmaid Hughes
May 21, 2011·BMC Evolutionary Biology·Fabian Svara, Daniel J Rankin
Dec 7, 2005·Plasmid·Keith E Weaver, Shirisha G Reddy
Apr 1, 2015·Trends in Microbiology·Aravindan IlangovanGabriel Waksman
Oct 22, 2011·Mobile Genetic Elements·Don B Clewell
Mar 13, 2015·Jundishapur Journal of Microbiology·Khalid Abdalla Ali AbdelRahimHeikal Abd El Hakim Abd El Azeiz

Related Concepts

Cell Division Phases
Centrifugation, Density Gradient
DNA, Bacterial
DNA, Circular
Antibiotic Resistance, Microbial
Cytoplasmic Inheritance
Cistron
Episomes
Recombination, Genetic
Enterococcus faecalis

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