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Center for Immunology and Microbial Disease, Albany Medical College, 47 New Scotland Ave., Albany, New York 12208,1 David Axelrod Institute, Wadsworth Center, New York State Department of Health, 120 New Scotland Ave., Albany, New York 12208,2 Department of Microbiology, University of Alabama at Birmingham, Birmingham, Alabama 35294-21703
Received 24 August 2006/ Accepted 28 October 2006
The accumulation of mutant genotypes within a biofilm evokes the controversy over whether the biofilm environment induces adaptive mutation or whether the accumulation can be explained by natural selection. A comparison of the virulence of two strains of the dental pathogen Streptococcus mutans showed that rats infected with one of the strains accumulated a high proportion (average, 22%) of organisms that had undergone a deletion between two contiguous and highly homologous genes. To determine if the accumulation of deletion mutants was due to selection or to an increased mutation rate, accumulations of deletion mutants within in vitro planktonic and biofilm cultures and within rats inoculated with various proportions of deletion organisms were quantified. We report here that natural selection was the primary force behind the accumulation of the deletion mutants.
Published ahead of print on 3 November 2006.
| J. Bacteriol. | Microbiol. Mol. Biol. Rev. | Eukaryot. Cell | All ASM Journals |
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