JKAOH Journal of Korean Academy of Oral Health

ISSN(Print) 1225-388X ISSN(Online) 2093-7784


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Original Article

Journal of Korean Academy of Oral Health 2016; 40(4): 255-260

Published online December 30, 2016 https://doi.org/10.11149/jkaoh.2016.40.4.255

Copyright © Journal of Korean Academy of Oral Health.

The pH-dependent effects of combining ethanol with fluoride on proton permeability in Streptococcus mutans

Sae-A Lee1, Seung-Il Jung1, Jin-Bom Kim2,3, Jung Sook Kang1

Departments of 1Oral Biochemistry & Molecular Biology, 2Preventive & Community Dentistry, 3BK21 PLUS Project, School of Dentistry, Pusan National University, Yangsan, Korea

Received: November 28, 2016; Revised: December 22, 2016; Accepted: December 24, 2016


Objectives: The aim of this research was to determine the pH-dependent changes in F-ATPase activity and proton fluxes in Streptococcus mutans (S. mutans) as induced by varying the concentration of fluoride ±10 mM (0.058% (v/v)) ethanol.Methods: S. mutans UA159 was grown in Brain Heart Infusion medium at pH 4.8, 6.8, or 8.8. The FATPase assay was initiated by the addition of ATP, and stopped by adding 10% trichloroacetic acid. For the proton flux assay, bacterial suspensions were titrated to pH 4.6 with 0.5 M HCl, and then 0.5 M HCl was added to decrease the pH values in units of approximately 0.4 pH. The subsequent increase in pH was monitored using a glass electrode. To disrupt the cell membrane, 10% (v/v) butanol was added to the suspensions after 80 minutes.Results: At all pH levels, fluoride ±10 mM ethanol not only decreased F-ATPase activity but also increased the proton permeability of S. mutans. The largest effects were observed at pH 4.8. Ethanol enhanced these effects only at pH 4.8.Conclusions: A very low concentration of ethanol enhanced the action of fluoride on F-ATPase activity and the proton permeability in S. mutans at acidic pH levels. We expect that low concentrations of ethanol may be used together with fluoride and/or other anticaries agents to develop more effective anticaries preparations.

Keywords: ethanol, F-ATPase, Fluoride, pH stress, proton permeability, Streptococcus mutans