Journal of Dental Research, Vol 55, 266-271, Copyright © 1976 by International & American Associations for Dental Research Online Journals
Plasmid DNA satellite bands seen in lysates of Streptococcus mutans that form insoluble extracellular polysaccharides
M. Higuchi, S. Araya and M. Higuchi
A satellite band of plasmid DNA was seen in cell lysates prepared from two
strains of S mutans using buoyant-density equilibrium centrifugation.
Mutants, defective in their ability to synthesize insoluble extracellular
polysaccharides, showed no detectable satellite DNA band when prepared by
the same procedure. These mutants were induced by treatment with EB,
acridine orange, or SDS, which are known to be effective agents for the
elimination of extrachromosomal genetic inheritance. The derived mutants
produced more soluble polysaccharides from sucrose than their parent
strains. The decreased ability to synthesize insoluble polysaccharides was
related to both glucan and fructan formation. These findings suggest that
the plasmid DNA of the S mutans strains genetically controls formation or
activity of the enzymes responsible for synthesis of extracellular
insoluble glucan or fructan.
