The relationship between sugar metabolism and potassium translocation by caries-inducing streptococci and the inhibitory role of fluoride

Luoma, H; Tuompo, Helena

doi:10.1016/0003-9969(75)90047-3

Cited by 42 publications

(28 citation statements)

References 26 publications

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“…This velocity was close to the speed of phosphate uptake by Streptococcus faecalis [Harold et al, 1965] and to the speed of the pH drop in dental plaque [e.g. Stephan, 1940;N eff, 1967] as well as the speed of potassium accumulation by the S. mutans cells in certain experimental situa tions [Luoma and Tuompo, 1975]. The ac cumulation of total phosphate by the fer menting S. mutans supports the isotope re sults and indicates that there was, indeed, a true accumulation of enamel phosphate by these bacteria, together with the uptake and accumulation of the nondental phosphate.…”

Section: Experiments 1: Uptake and Accumula Tion Of Enamel Phosphate Bsupporting

confidence: 66%

Phosphorus Translocation between Enamel and Streptococcus mutans in the Presence of Sucrose and Fluoride with Observations on the Acid Phosphatase of S. mutans

Luoma¹

1980

Caries Res

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Intact cells of Streptococcus mutans K-1 were incubated with enamel powder in buffer, pH 5.8, saturated with enamel salts, the cells or the enamel having been previously labelled with ³²P. The cells were also incubated with p-nitrophenyl phosphate at varying pH or at pH 4.8 with varying concentrations of fluoride. Incubation of the K-1 cells with ³²P-labelled enamel caused an equilibration of enamel ³²P within the cells. During sucrose fermentation, the uptake of enamel ³²P by the K-1 cells was rapidly increased several times higher than that of the controls. In the presence of fluoride, there was an increased liberation of bacterial ³²P and the uptake of this by enamel was doubled. There were changes in the bacterial total phosphate corresponding to the fermentative accumulation of ³²P of enamel origin within the cells or to the fluoride-induced release of ³²P out of them. The acid phosphatase of intact K-1 cells had a maximum activity at pH 4.8 and a lower peak at pH 5.8. At pH 4.8, a fluoride concentration of 20 ppm inhibited this activity almost to zero. The results emphasize the phosphate translocation between enamel and bacteria as a common denominator in the enamel destruction and repair, In the former case this and the acid phosphatase may support the acid attack. The results with fluoride may partly explain its caries-inhibitory functions.

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Section: Experiments 1: Uptake and Accumula Tion Of Enamel Phosphate Bsupporting

confidence: 66%

Phosphorus Translocation between Enamel and Streptococcus mutans in the Presence of Sucrose and Fluoride with Observations on the Acid Phosphatase of S. mutans

Luoma¹

1980

Caries Res

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“…Birkeland and Charlton [1976] have recently shown that decreases in plaque pH following microbial metabolism result in increased fluoride ion activity in the fluid phase. In addition, since recent studies indicate that some of the fluorine is accumu lated in bacteria [Kashket and Rodriguez, 1976;Luoma and Tuompo, 1975;Whiteford et al, 1977], more of the plaque fluo ride may be present in an active form than hitherto assumed. Yet, the present study was unable to demonstrate any difference between the microbial composition of plaque from children exposed, since birth, to negligible or extremely high levels of fluoride in the drinking water.…”

Section: Discussionmentioning

confidence: 99%

Predominant Plaque Flora of Tanzanian Children Exposed to High and Low Water Fluoride Concentrations

Kilian¹,

Thylstrup²,

Fejerskov³

1979

Caries Res

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The paper provides a detailed bacteriologic description of the predominant flora of supragingival plaque collected from 15 caries-free Tanzanian children exposed to negligible (0.3 ppm) and excessive (3–21 ppm) concentrations of fluoride in the water supply. The three predominant groups of bacteria in all samples were streptococci, veillonellae, and pleomorphic, gram-positive rods, which together accounted for 86.8% (mean) of cultivable flora. Streptococcus mitior was the single most predominant streptococcal species. Streptococcus mutans, mainly of serotype b, was isolated from two thirds of the samples and accounted for 2.3–21.4% of the streptococcal flora. Bacteria, which potentially metabolize lactate, i. e. veillonellae, neisseriae, propionibacteria, arachniae, Bacteroides asaccharolyticus, and Streptococcus jaecalis, comprised almost one half of the total flora (range 9–76%), and may conceivably be responsible for the negligible caries activity, despite the presence of highly acidogenic bacteria. There were no detectable differences in the flora of plaque samples from children exposed to high and low water fluoride concentrations, respectively. Previously observed fluoride-induced differences in the net metabolic product, and contents of extra- and intracellular polysaccharides of plaque, is probably to be explained by a direct interference of fluoride with plaque enzymes.

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“…This primary function of saliva depends on numerous secretory proteins as well as the ion composition. The K ϩ concentration of saliva modulates the activity and growth of the oral microbial flora, which include many species considered to be pathogenic (7,17,(45)(46)(47).…”

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confidence: 99%

Apical maxi-K (K_Ca1.1) channels mediate K⁺ secretion by the mouse submandibular exocrine gland

Nakamoto¹,

Romanenko²,

Takahashi³

et al. 2008

American Journal of Physiology-Cell Physiology

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The exocrine salivary glands of mammals secrete K+ by an unknown pathway that has been associated with HCO3− efflux. However, the present studies found that K+ secretion in the mouse submandibular gland did not require HCO3−, demonstrating that neither K+/HCO3− cotransport nor K+/H+ exchange mechanisms were involved. Because HCO3− did not appear to participate in this process, we tested whether a K channel is required. Indeed, K+ secretion was inhibited >75% in mice with a null mutation in the maxi-K, Ca2+-activated K channel (KCa1.1) but was unchanged in mice lacking the intermediate-conductance IKCa1 channel (KCa3.1). Moreover, paxilline, a specific maxi-K channel blocker, dramatically reduced the K+ concentration in submandibular saliva. The K+ concentration of saliva is well known to be flow rate dependent, the K+ concentration increasing as the flow decreases. The flow rate dependence of K+ secretion was nearly eliminated in K Ca 1.1 null mice, suggesting an important role for KCa1.1 channels in this process as well. Importantly, a maxi-K-like current had not been previously detected in duct cells, the theoretical site of K+ secretion, but we found that KCa1.1 channels localized to the apical membranes of both striated and excretory duct cells, but not granular duct cells, using immunohistochemistry. Consistent with this latter observation, maxi-K currents were not detected in granular duct cells. Taken together, these results demonstrate that the secretion of K+ requires and is likely mediated by KCa1.1 potassium channels localized to the apical membranes of striated and excretory duct cells in the mouse submandibular exocrine gland.

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The relationship between sugar metabolism and potassium translocation by caries-inducing streptococci and the inhibitory role of fluoride

Cited by 42 publications

References 26 publications

Phosphorus Translocation between Enamel and Streptococcus mutans in the Presence of Sucrose and Fluoride with Observations on the Acid Phosphatase of S. mutans

Phosphorus Translocation between Enamel and Streptococcus mutans in the Presence of Sucrose and Fluoride with Observations on the Acid Phosphatase of S. mutans

Predominant Plaque Flora of Tanzanian Children Exposed to High and Low Water Fluoride Concentrations

Apical maxi-K (K_Ca1.1) channels mediate K⁺ secretion by the mouse submandibular exocrine gland

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The relationship between sugar metabolism and potassium translocation by caries-inducing streptococci and the inhibitory role of fluoride

Cited by 42 publications

References 26 publications

Phosphorus Translocation between Enamel and Streptococcus mutans in the Presence of Sucrose and Fluoride with Observations on the Acid Phosphatase of S. mutans

Phosphorus Translocation between Enamel and Streptococcus mutans in the Presence of Sucrose and Fluoride with Observations on the Acid Phosphatase of S. mutans

Predominant Plaque Flora of Tanzanian Children Exposed to High and Low Water Fluoride Concentrations

Apical maxi-K (KCa1.1) channels mediate K+ secretion by the mouse submandibular exocrine gland

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Apical maxi-K (K_Ca1.1) channels mediate K⁺ secretion by the mouse submandibular exocrine gland