Ex vivo Uptake of Enamel Phosphate by Rothia dentocariosa and Gallein Inhibition - Data Sharing Archive

Abstract

A novel demineralization model tested the hypothesis that R. dentocariosa (Rd) can directly ingest tooth-derived orthophosphate (Pi). The study also examined if the internalization of tooth-derived Pi could be attenuated with gallein, an inhibitor of polyphosphate (polyP) kinases. Radionuclide 32P labeled remineralized bovine enamel (n=6) was exposed to Rothia dentocariosa (ATCC 17931) incubated in brain heart infusion (BHI) broth containing glucose. Attenuated total reflectance Fourier Transform Infrared (ATR-FTIR) spectroscopy and cross-polarization optical coherence tomography assessed the surface and subsurface characteristics of the remineralized and demineralized enamel surface. Liquid scintillation traced the 32P release from the tooth to the intracellular polyP in galleinpos/neg samples. FTIR determined that 32P was incorporated in dental enamel lesions and was released after exposure to an acidic buffer (pH=4.5) or Rd. After 24 hrs of exposure, galleinpos reduced R. dentocariosa’s planktonic growth and increased pH by 7.45% and 7.19% respectively compared to galleinneg. Planktonic cultures of R. dentocariosa galleinpos (25, 50, 100 mM) after 24 hrs decreased the ability of planktonic bacteria to be cultured directly on BHI agar plates by an order of magnitude more than galleinneg samples. Isotope labeling demonstrated that R. dentocariosa used Pi derived directly from the tooth for the benefit of the bacterium’s fitness through the formation of polyP. Gallein attenuated polyP accumulation, reduced bacterial cultivability, and may be a potential therapy option in the prevention and treatment of primary and secondary caries.