Adsorption of salivary mucins onto enamel and artificial solid substrata and its influence on oral streptococcal adhesion

Abstract

The effects of high molecular weight mucins, adsorbed on enamel and artificial solid substrata with various surface free energies, on oral streptococcal adhesion have been investigated. For the adhesion studies, 3 strains of oral streptococci with widely different surface free energies were used. The substrata were precoated with mucins with a molecular mass >10 5 Da. The adhesion of S. mutans NS to mucin coated, hydrophobic FEP-teflon was significantly increased by the presence of the mucin coating, whereas the adhesion of S. mutans NS to more hydrophilic substrata such as cellulose acetate, glass and enamel decreased. In addition, the adhesion of S. sanguis 12 and S. mitis BMS to mucin-coated surfaces decreased slightly. However, adhesion of S. sanguis to FEP-teflon remained unaltered.Unlike S. mitis, S. mutans and S. sanguis are known to possess specific carbohydrate receptor sites (lectins) which may interact with the carbohydrate part of adsorbed mucins. From the decrease in the adhesion of S. mutans to mucin-coated glass, it is concluded that mucins adsorb to glass with their polar carbohydrate part. On the other hand, it is hypothesized that mucins adsorb to FEP-teflon with their apolar protein part, thereby revealing their carbohydrate part towards the solution phase and stimulating the adhesion of S. mutans NS, while leaving the adhesion of S. sanguis 12 unaltered. Further evidence for this adsorption model of mucins is provided by contact angle measurements.

On the relative importance of specific and non-specific approaches to oral microbial adhesion

“…Contrary to the above, S. mutans adhered to mucin-coated hydrophobic substrata in much h~her numbers than to mucin-coated hydrophilic substrata [64], at odds with expectations on the basis of observations with bare substrata. R was hypothesized that the degree to which hidden receptor sites of the mucin molecule ('cryptitopes') for S. mutans were exposed, was regulated by the hydrophobicity of the substratum to which the mucin was adsorbed [6,21,65].…”

Physico-chemistry of initial microbial adhesive interactions – its mechanisms and methods for study

“…This explains why adhesion of oral streptococci to protein-coated substrata with di¡erent wettabilities is either in line with the thermodynamic approach based on bare substratum surface properties for adsorbed bovine serum albumin [134] or fully opposite, for adsorbed salivary mucins [215]. This explains why adhesion of oral streptococci to protein-coated substrata with di¡erent wettabilities is either in line with the thermodynamic approach based on bare substratum surface properties for adsorbed bovine serum albumin [134] or fully opposite, for adsorbed salivary mucins [215].…”

“…When, for instance, a conditioning ¢lm is an adsorbed, single-component protein layer, the conformation of the adsorbed proteins and spatial homogeneity of the ¢lm are governed by the substratum surface. This explains why adhesion of oral streptococci to protein-coated substrata with di¡erent wettabilities is either in line with the thermodynamic approach based on bare substratum surface properties for adsorbed bovine serum albumin [134] or fully opposite, for adsorbed salivary mucins [215]. Alternatively, when multicomponent conditioning ¢lms are involved, such as the salivary pellicle on teeth [19] or on the esophageal £ange of voice prostheses [160^162], tear ¢lm constituents (lysozyme, albumin, immunoglobulins, mucins and lipids) on contact lenses [163] and adsorbed proteins from plasma on polyurethane or silicone rubber [216^218], selective protein adsorption stimulated by the physico-chem-ical properties of the substrata may pass the in£uence of the substratum surface through the conditioning ¢lm to the interface with adhering microorganisms.…”

Physico-chemistry of initial microbial adhesive interactions – its mechanisms and methods for study

“…When, for instance, a conditioning film is an adsorbed, single‐component protein layer, the conformation of the adsorbed proteins and spatial homogeneity of the film are governed by the substratum surface. This explains why adhesion of oral streptococci to protein‐coated substrata with different wettabilities is either in line with the thermodynamic approach based on bare substratum surface properties for adsorbed bovine serum albumin [134] or fully opposite, for adsorbed salivary mucins [215]. Alternatively, when multicomponent conditioning films are involved, such as the salivary pellicle on teeth [19] or on the esophageal flange of voice prostheses [160–162], tear film constituents (lysozyme, albumin, immunoglobulins, mucins and lipids) on contact lenses [163] and adsorbed proteins from plasma on polyurethane or silicone rubber [216–218], selective protein adsorption stimulated by the physico‐chemical properties of the substrata may pass the influence of the substratum surface through the conditioning film to the interface with adhering microorganisms.…”