Distribution of sulphated macromolecules in the salivary secretions of macaca irus

Structural studies of human saliva

Samples of mixed saliva and of parotid and sublingual/submandibular saliva fractions from four donors were subjected to instantaneous solidification in liquid nitrogen followed by sectioning in a microtome/cryostat. The sections were stained with hematoxylin-eosin, periodic acid-Schiff, Alcian blue, Oil-red-O, or Sudan Black B and then examined at the light-microscopic level. In all the sectioned samples several previously never described features were observed, the most pronounced of which were a loose overall network structure and collections of lipoid droplets often in a loose arrangement. In the mixed saliva sample sections many of the microorganism-like structures were observed in large bunches associated with epithelial cells and densely staining saliva components. The present method was tested in a series of experiments for possible errors.

Isolation, chemical and biological characterization of sulphated glycoproteins synthesized by rat buccal and palatal minor salivary glands in vivo and in vitro

35S-labelled sulphated glycoproteins (SGP) were isolated from these glands after the incorporation of radiosulphate in vivo and in vitro by fractionation of tissue and medium extracts on Sepharose 4B and partial purification by DEAE-Sephacel anion exchange chromatography. Fractions were assessed for purity by SDS-PAGE and by cellulose-acetate electrophoresis. Molecular weights ranged from 34,000 to 5 X 10(6). It was notable that the molecular size of SGP from the in vitro media was generally lower than from the corresponding tissue fractions, particularly for the palatal samples. The fractions were heterogeneous and contained no sulphated glycosaminoglycans; they had high levels of aspartic acid, glutamic acid, threonine and serine, but there was no major difference in amino-acid composition between them. Carbohydrate analysis indicated typical components associated with sulphated glycoproteins, including fucose, galactose, glucose, mannose, N-acetylgalactosamine, N-acetylglucosamine and N-acetylneuraminic acid. Protein:carbohydrate ratios ranged from 0.1:1.0-3.5:1.0 and ester sulphate from 0.8 to 16.2 per cent. All fractions exhibited blood-group A reactivity and aggregated Streptococcus sanguis NCTC 7864; several fractions interacted similarly with Streptococcus mutans OMZ61.

Differential adsorption and chemical affinities of proteins for apatitic surfaces

Studies are reviewed which identify the interacting groups involved in protein adsorption onto hydroxyapatite. Thus, carboxyl and phosphoester groups bind to calcium sites in the adsorbent, and basic groups bind to phosphate sites. Detailed adsorption studies have been performed to quantitate some of these interactions. An adsorption model, based on the Langmuir adsorption isotherm, adequately fitted the data from experiments using selected amino acids, bovine albumin and two human salivary proteins. Adsorption parameters (affinities and maximum number of sites) were obtained for several apatitic adsorbents, with affinities increasing considerably in the series hydroxy- (HA), fluorhydroxy- (FHA) and fluorapatite (FA). A modest increase in the number of sites was also noted. The change in adsorption behavior, with increasing fluoride content, was attributed to a reduction in the surface free energy of the adsorbent, with a concomitant decrease in the interaction of the adsorbent with water, and a consequent enhancement of the adsorption bond. It is suggested that this effect may play a role in the cariostatic effect of fluoride. Unusual structural aspects of the salivary proteins are discussed in relation to their adsorption behavior, and the molecular segments responsible for binding to the adsorbent tentatively identified.

Is sulphated blood-group substance in pancreas a factor in cystic fibrosis?

The present study showed that the pancreas of two monkey species contained sulphated blood-group substance. Such strongly anionic molecules are known to bind calcium, and their solutions form gels in the presence of cations. It is suggested that such a mechanism may be involved in cystic fibrosis.

Biochemical and immunological comparison of monkey (Macaca arctoides) and human salivary secretions

1. Salivary secretions of the stumptail monkey (Macaca arctoides) were compared biochemically and immunologically with human salivas. 2. Similarities in biochemical composition and antigenic profiles as seen by immunoelectrophoresis indicate that monkey salivas can provide an excellent model system to study the role of saliva in the oral ecology of man.

A sulphated glycopeptide in human supragingival calculus extracts

A method is described for the isolation and purification of a sulphated glycopeptide from human supragingival calculus. The compound was isolated after using EDTA treatment, 2 M CaCl2 extraction, proteolytic digestion, ethanol precipitation, and finally purified by DEAE cellulose chromatography. It migrated as a single component of cellulose acetate electrophoresis, and chemical and infrared spectral analysis showed the presence of covalently attached sulphate groups. The sulphated glycopeptide was distinguished from being a sulphated glycosaminoglycan.

Less dental caries among secretors than among non-secretors of blood group substance

Salivary mucins can aggregate oral bacteria and also constituents of pellicle and plaque. A,B, and H blood group antigens are present on the mucins of secretors only. These mucins have also been shown to contain more carbohydrate than non-secretor mucins. The aim of the present study was to relate these genetically determined differences in mucin composition to caries prevalence. Data on blood group, secretor status, and caries prevalence were collected from 69 dental students. In all blood groups, the average caries prevalence was lower for secretors than for non-secretors. The difference was more pronounced for smooth surface than for total surface prevalence. The secretors of blood group mucin A had the lowest caries prevalence. The results would be consistent with an impact of the mucin composition upon the caries prevalence, and possible mechanisms are discussed.

The murine sublingual and submandibular mucins. Their isolation and characterization

From the mouse sublingual and submandibular glands high-molecular weight glycoproteins (mucins) were isolated. These mucins appeared to be homogeneous in polyacrylamide gel electrophoresis and in the analytical ultracentrifuge. S20,W values of 10.9 and 5.5 were found for the sublingual and submandibular mucin respectively. With sodium dodecyl sulfate or N-acetylcysteine no subunits could be detected. Both mucins consisted for about 1/3 of protein and 2/3 carbohydrate. Their mucin character was also denoted by the high content of serine plus threonine. Respectively 42 mol% and 34 mol% of the protein core of the sublingual and submandibular mucins consisted of these amino acids. The main sugars in these mucins were sialic acid, galactosamine, galactose, glucosamine and mannose. The molar ratio for the sublingual and submandibular mucin being 1.00 : 1.03 : 1.08 : 0.26 : 0.23 and 1.00 : 0.71 : 1.10 : 0.65 : 0.53, respectively. The sialic acid content of both mucins was about 25%. Fucose and sulfate, on the other hand, were less than 1%. The presence of sulfate was also indicated by preliminary studies in vivo on the incorporation of [35SO4] sulfate.