Inhibition of Streptococcus mutans by the antibiotic streptozotocin: mechanisms of uptake and the selection of carbohydrate-negative mutants.
The antibiotic streptozotocin [2-deoxy-2-(3-methyl-3-nitrosoureido)-D-glucopyranoside], an analog of N-acetylglucosamine (NAG), has been shown to be useful for the selection of carbohydrate-negative and auxotrophic bacterial mutants. We have adapted this method for use with the oral pathogen Streptococcus mutans, a gram-positive, aerotolerant anaerobe that uses predominantly carbohydrates as carbon sources for growth. Streptozotocin selectively kills growing cells of S. mutans GS-5, and under appropriate conditions it can reduce the number of viable cells in actively growing cultures by a factor of 10(3) to 10(4). However, unlike in enteric bacteria, which take up this antibiotic by a single NAG-specific transport system, streptozotocin appears to be taken up in S. mutans by both a NAG-specific system and a relatively nonspecific system that is also involved in glucose, fructose, and mannose uptake. Combining streptozotocin selection and a screening procedure involving indicator plates containing triphenyl-tetrazolium chloride, we developed a general method for the isolation of carbohydrate-negative and auxotrophic mutants of S. mutans. A preliminary characterization of both pleiotropic and specific carbohydrate-negative mutants isolated by using this procedure is presented.
Jacobson
G R
GR
Department of Biology, Boston University, Massachusetts 02215.
Poy
F
F
Lengeler
J W
JW
D000117:Acetylglucosamine / Q000493:pharmacokinetics; D050260:Carbohydrate Metabolism; D009154:Mutation; D010766:Phosphorylation; D013295:Streptococcus mutans / Q000187:drug effects* / Q000254:growth & development / Q000378:metabolism; D013311:Streptozocin / Q000493:pharmacokinetics / Q000494:pharmacology*
D013311:Streptozocin; D000117:Acetylglucosamine