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Preliminary characterization of four bacteriocins from Streptococcus mutans
M Parrot1, P W Caufield, M C Lavoie
1Département de biochimie et Ecole de médecine dentaire, Université Laval, Québec, Québec, Canada.
Canadian Journal of Microbiology
|February 1, 1990
Summary
Streptococcus mutans produces mutacins, potent antibacterial substances. These mutacins exhibit varying properties, with some being heat-resistant and active against Gram-positive bacteria, suggesting chromosomal gene location.
Area of Science:
- Microbiology
- Bacteriology
- Molecular Biology
Background:
- Streptococcus mutans strains are known producers of inhibitory substances.
- Previous studies have not definitively classified these substances.
- Understanding these substances is crucial for controlling oral bacteria.
Purpose of the Study:
- To characterize the inhibitory substances produced by four strains of Streptococcus mutans.
- To classify these substances based on their properties and activity.
- To investigate the genetic basis of mutacin production.
Main Methods:
- Characterization of inhibitory substances by testing for heat resistance, molecular weight, and sensitivity to proteolytic enzymes.
- Determination of activity spectrum against Gram-positive and Gram-negative bacteria.
- Analysis of bacterial DNA for plasmid presence and restriction-fragment patterns.
Main Results:
- Inhibitory substances were classified as mutacins, distinct from lactic acid, bacteriophages, or hydrogen peroxide.
- Three strains (C67-1, Ny266, T8) produced similar thermoresistant, low molecular weight mutacins active against Gram-positive bacteria.
- One strain (Ny257-S) produced a mutacin with lower thermoresistance and higher molecular weight.
- No plasmid DNA was detected, suggesting mutacin genes are chromosomal.
- Strains C67-1 and T8 showed close genetic relatedness based on mutacin properties and DNA patterns.
Conclusions:
- The characterized inhibitory substances are confirmed as mutacins.
- Mutacin properties vary among Streptococcus mutans strains, influencing their activity and classification.
- Chromosomal genes likely encode mutacins, with evidence of close genetic relationships between certain strains.