Adhesion Profile Research Articles

A Comparison of the Adhesion Profiles and Cell Surface Characteristics ofStreptococcus mitiswith those of Other Members of theStreptococcus sanguisGroup

A collection of 12 strains of Streptococcus mitis were tested for their in vitro adhesion profiles and compared to those of other strains within the Streptococcus sanguis group (SSG). The S. mitis isolates from saliva and the strains isolated from plaque gave significantly greater cell surface hydrophobicities ( P < 0.01) than isolates from other sites. The saliva isolates were generally not aggregated by saliva wherea s S. sanguis I and II strains gave aggregation values over a wide range. Strains from all species gave a wide range of values for adhesion to saliva-coated hydroxyapatite (SHA), but isolates from dental plaque adhered significantly ( P < 0.01) better to SHA than other isolates. The adhesion to SHA was not related to cell surface hydrophobicity or salivary aggregation. Strain pairs were allowed to interact with each other in the SHA adhesion assay. Homologous pairings usually gave reduced adhesion as did some non-homologous pairings, possibly as the result of occupying similar salivary receptors. Occasionally non-homologous pairings increased the adhesion of one member suggesting that certain SSG strains can modify the salivary pellicle to facilitate the adhesion of other SSG strains. Most strains were poor adherers to buccal epithelial cells (BEC), although S. sanguis I strains were more adhesive ( P < 0.025) than other species/biotypes. Serological tests on SSG strains for surface antigens showed 12 per cent reactivity with antisera to lipoteichoic acid and 40 per cent reactivity with antisera to protein P1; in neither case was there a correlation with adhesion to SHA or BEC or aggregation by saliva. Strains of S. mitis were more likely to coaggregate with veillonella than with actinomyces strains, whereas strains of S. sanguis tended to coaggregate with representatives of both genera. Keywords: Adhesion; Saliva; Streptococcus mitis ; Streptococcus sanguis ; Surface antigens; Coaggregation; Hydrophobicity.

Investigation of applied compression on the adhesion of powders to a substrate surface

The influence of applied forces on the adhesion of classified pharmaceutical polyethyleneglycol(PEG) 4000, Starch 1500, spray-dried lactose and heavy precipitated calcium carbonate onto a characterized stainless steel substrate has been investigated using a centrifuge technique. The particles of each powder were initially forced onto the substrate surface by centrifuging at a particular speed, and immediately after this stage, the adhesion profile was determined. Once a minimum value for the adhesion force had been achieved, over the range of the applied forces, all powders displayed a statistical log—normal distribution of the percentage of adherent particles with respect to the adhesion forces. The geometric median force of adhesion for all powders was found to increase linearly with the preliminary applied force. The slope of each regression line indicated quantitatively the change of the median adhesion force per unit increase of the applied force. This value was dimensionless and that evaluated for PEG 4000 was 33.3 × 10 −1, Starch 1500 7.57 × 10 −2, spray-dried lactose 1.72 × 10 −2 and calcium carbonate 1.63 × 10 −2.

A Comparison of the Adhesion Profiles and Cell Surface Characteristics ofStreptococcus mitiswith those of Other Members of theStreptococcus sanguisGroup

A Comparison of the Adhesion Profiles and Cell Surface Characteristics of<i>Streptococcus mitis</i>with those of Other Members of the<i>Streptococcus sanguis</i>Group

The effect of protein and urine on uropathogen adhesion to polymer substrata

Uropathogenic adhesion was measured using a range of polymer materials with differing surface tension properties. Experiments were carried out in the presence of phosphate buffered saline (controls), Tamm Horsfall protein (THP), and human urine with quantitation by image analysis. The results showed that THP did not bind to the polymer materials and therefore did not act as a receptor surface for type 1 fimbriated Escherichia coli. However, the THP did interfere with adhesion by binding directly to these organisms as well as to Pseudomonas aeruginosa, Staphylococcus epidermidis, and, to a lesser extent, Proteus mirabilis. Incubation of the uropathogens in THP and urine resulted in altered adhesion profiles to polymer surfaces, with no single trend apparent. The results emphasize that fluid components, particularly proteins, and substratum surface tension influence bacterial adhesion to biomaterials.

Adherence, haemagglutination and cell surface characteristics of motile aeromonads virulent for fish

Abstract. Motile Aeromonas spp. virulent for fish were studied with regard to their adhesion profile. Electron microscopy demonstrated the presence of fimbriae (pili) on Aeromonas cells regardless of virulence potential. The results show no significant correlations between ability to haemagglutinate, yeast cell co‐agglutination and virulence. All strains expressed mannose‐sensitive haemagglutinin activity against guinea pig erythrocytes. Using four types of red blood cells no characteristic haemagglutinin pattern related to virulence could be discerned. Expression of surface haemagglutin(s) on Aeromonas hydrophila appears to be medium dependent; strains grown in liquid media demonstrated enhanced haemagglutination activity. Both virulent and avirulent strains had in vitro epithelial cell adhesive capabilities. Cell surface characteristics measured by agglutination in acriflavine and stability after boiling indicated that most virulent strains agglutinated in the presence of acriflavine, but not all sedimented after boiling. The ability of 10 selected strains of A hydrophila to grow in normal pooled catfish serum was determined. Only 17% of the virulence variations can be explained by their sensitivity to serum.

Exclusion of uropathogen adhesion to polymer surfaces by Lactobacillus acidophilus

The ability of bacteria to adhere to surfaces is a major cause of concern in the use of biomaterial substrates. The adhesion of Staphylococcus epidermidis strain 1938 was examined using image analysis and was found not to correlate with polymer surface tension, unlike that of Lactobacillus acidophilus, which adhered to more hydrophobic polymers. A fimbriated uropathogenic E. coli strain showed very low levels of adherence to the biomaterials. Precoating the polymers with lactobacilli significantly reduced the staphylococcal and E. coli adhesion, a result which could have clinical significance. An additional finding was that the interaction of staphylococci and E. coli with lactobacilli coated polymers altered the adhesion profile of the latter. Lactobacilli appeared to detach from polymers of low surface tension and reattach to polymers with high surface tensions. This resulted in the highest levels of exclusion of uropathogens being found for lactobacilli-coated glass and sulfonated polystyrene, both of which are hydrophilic (with high surface tensions). These results demonstrate that lactobacilli can be used to coat biomaterial surfaces leading to a reduced adhesion of uropathogens.

Fundamental considerations in the measurement of adhesional forces between particles using the centrifuge method

The adhesional characteristics of interactive mixtures of HPMCP-coated glass spheres and several powdered drugs were investigated using a specially designed centrifuge cell. The adhesion profile of percent of drug remaining on the carrier versus the square of the speed of rotation was log normally distributed; the degree of adhesion could be characterized by the speed of rotation to detach 50% of the particles ( S 50) and the standard deviation of the distribution (σ). All the powders tested using this model interactive system possessed log normal adhesion profiles. The system was validated by testing the effect of the interactive mixture loadings and the time of centrifuging at each rotational speed on the adhesion profile. Loads between 60 and 150 mg, and centrifuging times of 30 and 60 s caused no significant change to the S 50 value obtained for a sulphapyridine interactive mixture.

Comparative studies on the effect of growth conditions on adhesion, hydrophobicity, and extracellular protein profile of Streptococcus sanguis G9B

Streptococcus sanguis G9B was grown in continuous culture at different generation times and pH values in media containing either glucose or fructose and differing in the concentrations of Na+ and K+. The growth pH, carbohydrate, and cation concentration each affected the yield of organisms, their ability to adhere to saliva-coated hydroxyapatite beads, and their hydrophobicity, as measured by adhesion to hexadecane. There was no correlation between adhesion to saliva-coated hydroxyapatite beads and hydrophobicity, the values for hydrophobicity varying between 44 and 83% for organisms that adhered poorly and between 24 and 75% for those that adhered effectively. For organisms grown in batch culture at pH 6.0 or 7.0 there was similarly no correlation between adhesion and hydrophobicity. The growth conditions also had a considerable influence on the production of extracellular protein. The total amount was greater at pH 7.5 than at other pH values, and there were also differences in the individual components in response to changes in generation time, pH, carbohydrate source, and cation concentration. Two protein bands were identified, namely, glucosyltransferase and protein P1 (also called antigen B or I/II). However, there was no correlation between a particular protein component and adhesion.

The effect of membrane-fluidizing agents on the adhesion of CHO cells.

Treatment of CHO cells with drugs which are known to increase membrane lipid fluidity reduced the cells' ability to adhere to protein coated substrates, The concentrations of local anesthetics, nonionic detergents or aliphatic alcohols required to reduce CHO cell adhesion by 50% were similar to those reported to block nerve conduction, indicating that these drugs can affect the membrane at physiologically significant concentrations. Nonionic detergents and aliphatic alcohols, but not local anesthetics, caused increases in the fluidity of CHO plasma membranes (measured by fluorescence polarization) at concentrations which inhibited cell adhesion. The adhesion versus temperature profile had a sigmoidal shape, suggesting that a temperature dependent cooperative process such as a lipid phase transition, might be involved. However, the temperature profile for CHO membrane fluidity manifested no discontinuities, indicating the absence of any discrete phase transitions of the lipid matrix. This observation, coupled with the result that the inhibition of CHO cell adhesion produced by low temperatures was not relieved by drugs which can increase membrane fluidity, suggests that the reduced adhesion seen at low temperature is probably not due to reduced lipid fluidity.