Abstract
The uptake of protons by intact cells of Streptococcus mutans GS-5 was measured directly by assessing the pH increase in lightly buffered cell suspensions as protons moved across the plasma membrane after acid pulses. The barrier function of the cell membrane for protons was disrupted completely by 5% (vol/vol) butanol. This function was compromised severely by the ionophores valinomycin and gramicidin and by the uncoupler carbonylcyanide-m-chlorophenyl hydrazone. Proton conduction across the membrane was also enhanced by fluoride. It appeared that HF traversed the membrane and acted as a carrier. Once in the relatively alkaline cytoplasm, HF dissociated to yield F- and H+, which acted to acidify the cytoplasm and reduced the pH difference across the membrane.
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Selected References
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- Eisenberg A. D., Bender G. R., Marquis R. E. Reduction in the aciduric properties of the oral bacterium Streptococcus mutans GS-5 by fluoride. Arch Oral Biol. 1980;25(2):133–135. doi: 10.1016/0003-9969(80)90089-8. [DOI] [PubMed] [Google Scholar]
- Eisenberg A. D., Marquis R. E. Uptake of fluoride by cells of Streptococcus mutans in dense suspensions. J Dent Res. 1980 Jul;59(7):1187–1191. doi: 10.1177/00220345800590072801. [DOI] [PubMed] [Google Scholar]
- Hamilton I. R. Effects of fluoride on enzymatic regulation of bacterial carbohydrate metabolism. Caries Res. 1977;11 (Suppl 1):262–291. doi: 10.1159/000260304. [DOI] [PubMed] [Google Scholar]
- Harold F. M., Van Brunt J. Circulation of H+ and K+ across the plasma membrane is not obligatory for bacterial growth. Science. 1977 Jul 22;197(4301):372–373. doi: 10.1126/science.69317. [DOI] [PubMed] [Google Scholar]
- Scholes P., Mitchell P. Acid-base titration across the plasma membrane of Micrococcus denitrificans: factors affecting the effective proton conductance and the respiratory rate. J Bioenerg. 1970 Jun;1(1):61–72. doi: 10.1007/BF01516089. [DOI] [PubMed] [Google Scholar]
- Ui M. A role of phosphofructokinase in pH-dependent regulation of glycolysis. Biochim Biophys Acta. 1966 Aug 24;124(2):310–322. doi: 10.1016/0304-4165(66)90194-2. [DOI] [PubMed] [Google Scholar]
- Whitford G. M., Schuster G. S., Pashley D. H., Venkateswarlu P. Fluoride uptake by Streptococcus mutans 6715. Infect Immun. 1977 Dec;18(3):680–687. doi: 10.1128/iai.18.3.680-687.1977. [DOI] [PMC free article] [PubMed] [Google Scholar]