Fluoride and gallein inhibit polyphosphate accumulation by oral pathogen Rothia dentocariosa

Area of Science:

• Microbiology
• Biochemistry
• Oral Health

Background:

• Polyphosphate (polyP) accumulating bacteria, like Rothia dentocariosa, can influence mineral dissolution in the oral cavity through orthophosphate (Pi) uptake and storage.
• Understanding the mechanisms controlling Pi metabolism in oral bacteria is crucial for oral health research.

Purpose of the Study:

• To investigate the effects of potential polyphosphate kinase inhibitors, gallein and fluoride, on the Pi metabolism of Rothia dentocariosa.
• To determine if these inhibitors affect bacterial growth, extracellular Pi drawdown, and intracellular polyP synthesis.

Main Methods:

• Rothia dentocariosa cultures were treated with varying concentrations of gallein and sodium fluoride (NaF).
• Extracellular Pi was quantified using an ascorbic acid assay.
• Intracellular polyP was isolated, hydrolyzed, and quantified.
• Attenuated total reflectance-Fourier-transform infrared spectroscopy (ATR-FTIR) was used to validate polyP presence and concentration.

Main Results:

• Gallein and fluoride significantly attenuated the bacterial drawdown of extracellular Pi.
• Both inhibitors markedly decreased intracellular polyP synthesis in R. dentocariosa.
• ATR-FTIR confirmed reduced polyP levels in treated bacterial cells.
• Gallein and fluoride showed minor effects on bacterial growth, with NaF impacting media pH.

Conclusions:

• Rothia dentocariosa actively modulates extracellular Pi and accumulates intracellular polyP.
• Gallein and NaF effectively attenuate this Pi metabolism mechanism in R. dentocariosa.
• These findings suggest potential therapeutic targets for managing oral conditions influenced by bacterial Pi metabolism.