A protein, which can agglutinate a Streptococcus mutans serotype c strain, was isolated from parotid saliva by affinity adsorption of the salivary agglutinin to the microorganism followed by a desorption with a 10 mM phosphate buffer. The agglutinin was subjected to preparative ultracentrifugation, gel filtration, and ultrafiltration. The native purified agglutinin is active only in the presence of Ca. Polyacrylamide gel electrophoresis, analytical centrifugation, and analyses of amino acids and carbohydrates showed that the native agglutinin was a fucose-rich glycoprotein with a carbohydrate content of 45 % and with a molecular weight of at least 5 x lo6. After sodium dodecyl sulphate treatment the molecular weight was 4.4 x 10'. There was a low content of proline and a high content of aspartic acid, serine and threonine. The concentration of agglutinin in parotid saliva is less than 0.5 % of total protein. It has high biological activity: 0.1 pg agglutinin causes a rapid aggregation of approximately lo8 bacteria.The compositions of secretions produced by different exocrine cells in various mucosal tissues are remarkably alike. The characteristics are the presence of potentially antibacterial systems, like secretory IgA, lactoperoxidase, lactoferrin and lysozyme, as well as of high-molecular-weight glycoproteins, which traditionally have been ascribed the role of lubricants. However, it has become evident that some of the highmolecular-weight glycoproteins also carry antibacterial properties [I, 21. Like secretory IgA, and under some conditions lysozyme also, they serve as bacterial agglutinins.The high-molecular-weight glycoproteins bind to surface receptor sites on microorganisms and under certain conditions they cause aggregation of microorganisms [2]. Aggregation or mere coating of microorganisms by salivary bacteriaaggregating glycoproteins or secretory IgA is suggested to contribute to the elimination of microorganisms from the oral cavity by blocking attachment sites on the bacterial surface. It has been suggested [I] that similarity in chemical structure between soluble glycoproteins and epithelial surface receptors, which recognize bacteria, would give rise to an intersepting mechanism, which prevents the bacteria from becoming attached to the epithelial surface.On the other hand, agglutinins, incorporated in the glycoprotein coat of the mucosa or in the acquired pellicle of the tooth surface, may favour attachment of bacteria [I, 3, 41. The balance between clearance and attachment of bacteria results in a selection of the bacteria colonizing the different surfaces [l -3, 51. It is, therefore, of prime interest to study the selecting mechanisms leading to retention of pathogenic microorganisms.In the present study we have isolated and characterized a glycoprotein which agglutinates a serotype c strain of Streptococcus mutans. Serotype c strains of S. mutam are recognized as cariogenic (for review see [6] significance of and some characteristics for the agglutinin specific for these strains have been de...

The application range of microchips can be extended to any mode of chromatography by filling the narrow channels with continuous polymer beds, exemplified by electrochromatography and ion-exchange chromatography. “Wall effects” are eliminated by anchoring the bed to the wall of the channel, an arrangement which has the additional advantage that no frits to support the bed are required. The design of the equipment is based on a quartz chip with all auxiliary pieces (for example, electrode vessels and fluid transfer fittings) placed in a rack, which permits a flexibility of great importance for automation. The same resolution and van Deemter plots were obtained in experiments performed in fused-silica capillaries and in chips for both low-molecular-weight (alkyl phenones, antidepressants) and high-molecular-weight substances (proteins). A sample of uracil, phenol, and benzyl alcohol was separated by electrochromatography in less than 20 s.

No abstract

– In an earlier study, we found that chronic treatment with β2‐adrenoceptor agonists in asthmatic subjects gave an impaired saliva secretion and a higher caries prevalence than in healthy controls. Twenty‐one of the asthmatics and their matched controls were examined 4 yr later in a follow‐up study. Samples of whole saliva stimulated by chewing and parotid saliva stimulated by citric acid were collected and dental caries was scored. In the asthmatic group the secretory rates of stimulated whole and parotid saliva decreased by 20% and 35%, respectively, compared to the control group. The number of lactobacilli increased. The asthmatic subjects had a decreased output per minute of total protein, amylase, hexosamine, salivary peroxidase, lysozymc, secretory IgA, a bacteria‐aggregating glycoprotein, potassium, and calcium in stimulated parotid saliva. Initial and manifest caries lesions as well as the number of DFS were significantly increased in the asthma group. We conclude that asthmatic patients treated with β2‐adrenoccptor agonists have an increased caries susceptibility due to an impaired saliva secretion caused by the use of β‐adrenergic agonists.

No abstract