Interaction of streptococcal lipoteichoic acid with artificial tooth pellicle

Area of Science:

• Oral microbiology
• Biomaterials science
• Biochemistry

Background:

• Artificial pellicles mimic natural tooth surfaces.
• Lipoteichoic acid is a key component of Gram-positive bacterial cell walls.
• Understanding bacterial adhesion to oral surfaces is crucial for preventing dental diseases.

Purpose of the Study:

• To investigate the binding characteristics of lipoteichoic acid to saliva-coated hydroxyapatite.
• To determine the nature of the interaction (e.g., hydrophobic, electrostatic).
• To identify potential salivary components involved in modulating this binding.

Main Methods:

• Preparation of artificial pellicles by coating hydroxyapatite beads with whole human saliva.
• Isolation and radiolabelling of lipoteichoic acid from Streptococcus sanguis.
• Quantification of lipoteichoic acid binding using liquid scintillation counting.
• Analysis of binding data using Scatchard and double reciprocal plots.
• Investigation of binding in the presence of various inhibitors and salivary components.

Main Results:

• Lipoteichoic acid exhibited hydrophobic binding to the artificial pellicle.
• The interaction was complex, involving multiple binding sites with varying affinities.
• A high association constant (1.1 x 10^9 M^-1) and a large number of binding sites (3.9 x 10^12/mm^2) were determined.
• Salivary mucin competitively inhibited lipoteichoic acid binding.

Conclusions:

• The hydrophobic interaction between lipoteichoic acid and the artificial pellicle is a significant factor in bacterial adhesion.
• Salivary mucins play a role in regulating this adhesion, potentially through competitive binding.
• These findings contribute to understanding the initial stages of oral biofilm formation.