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

Abstract

Streptococcus sanguis G9B was grown in continu6tis 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 productibn 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 catidn 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.

Modulation of glycosidase and protease activities by chemostat growth conditions in an endocarditis strain of Streptococcus sanguis

“…A chemostat study with a S. sanguis group strain showed that total extracellular protein more than doubled when culture pH was increased from 5.5 to 7.5. In addition, extracellular pro-teins which were minor or absent at one growth pH were major proteins at the other growth pH (26). In the present work when S. sanguis FSS2 was grown in the chemostat at 3 different pH levels, modulation of the specific activity of the 5 selected activities was observed (Fig.…”

“…We studied phenotypic modulation by S. sanguis FSS2 in response to changing growth conditions in the chemostat. Previous work with S. sanguis group bacteria grow^n in chemostat culture has shown that extracellular protein profiles of Streptococcus gordonii {sanguis) G9B were altered by changes in growth rate, pH and composition of growth medium (26), and that relative amounts of endo-, exo-, and amino-peptidase activities changed when S. sanguis P4A7 was switched from glucose-limited to glucose-excess (nitrogen-limited) conditions (39). In chemostat mixed culture experiments, the S. sanguis group organisms S. sanguis and Streptococcus oralis produced exoglycosidases allowing growth on mucin as the sole carbon source (43), and mixed chemostat cultures of oral bacteria increased synthesis of glycosidases when mucin was the sole carbon source (3).…”

“…Bacterial growth rate influences many cellular properties, including specific activities of some enzymes (4,10,37). In chemostat-grown oral streptococci (including S. sanguis group strains), the following properties depend on growth rate: extracellular protein profile (26), rates of glycolysis, glucose uptake, and phosphenolpyruvate: glucose phosphotransferase activity (11), glycogen content (15), extracellular glucosyltransferase activity (16) and protease activity (39).…”

Isolation and characterization of a non‐adherent mutant of Streptococcus sanguis G9B

“…This difference may account for the variations in "hydrophobicity" reported by investigators using different buffer systems. It seems likely, based on our observations and those reported recently by several other investigators (23,49,50) that hydrophobic interactions represent only one of the non-covalent interactions involved in the attachment of 5*. sanguis to SHA (17,37,49).…”

Cell surface mutants of Streptococcus sanguis with altered adherence properties

“…The characterization of various wildtype strains and adherence-defective mutant strains of S. sanguis has provided evidence that the ability of cells to adhere to SHA (3,8,12) or to coaggregate with actinomycetes (17) is associated with the hydrophobicity of the cell surface. Notwithstanding this, some mutants of 5. sanguis that are defective in adherence have increased hydrophobicity (8), and Knox et al (20) were unable to correlate adherence with hydrophobicity for cells grown under a variety of different conditions. The results in this paper support the view that cell surface hydrophobicity is a strong determinant in S. sanguis adherence.…”