No abstract

The differences in binding in vitro may indicate that there are also differences in the persistence of the different probiotic strains in the oral cavity in vivo.

Permanent colonization of LGG in the oral cavity is improbable but seems possible in individual cases.

Smoking significantly decreased both biomarkers studied. Compared to girls, boys seem to have enhanced susceptibility for periodontitis as reflected in salivary MMP-8 values.

Although S-layers are being increasingly identified on Bacteria and Archaea, it is enigmatic that in most cases S-layer function continues to elude us. In a few instances, S-layers have been shown to be virulence factors on pathogens (e.g. Campylobacter fetus ssp. fetus and Aeromonas salmonicida), protective against Bdellovibrio, a depository for surface-exposed enzymes (e.g. Bacillus stearothermophilus), shape-determining agents (e.g. Thermoproteus tenax) and nucleation factors for fine-grain mineral development (e.g. Synechococcus GL 24). Yet, for the vast majority of S-layered bacteria, the natural function of these crystalline arrays continues to be evasive. The following review up-dates the functional basis of S-layers and describes such diverse topics as the effect of S-layers on the Gram stain, bacteriophage adsorption in lactobacilli, phagocytosis by human polymorphonuclear leukocytes, the adhesion of a high-molecular-mass amylase, outer membrane porosity, and the secretion of extracellular enzymes of Thermoanaerobacterium. In addition, the functional aspect of calcium on the Caulobacter S-layer is explained.

Specific periodontal microorganisms appeared to induce host response, with increased release of MMP-8 and MMP-9 in gingival pockets as well as of MMP-9 in plasma, possibly triggering its up-regulation in blood.

We studied the presence of secondary Sjögren's syndrome (SS) and the composition of saliva, prevalence of oral pathogens, periodontitis, mouth mucosa, and teeth in patients with various rheumatic diseases and in healthy controls. The hypothesis was that different rheumatic diseases might cause differences in oral health characteristics because of the liability of secondary SS in the patients. The study involved 77 patients and 77 age-matched and sex-matched controls. Twenty patients were suffering from spondylarthropathy (SPA), 18 from ankylosing spondylitis (AS), 24 from rheumatoid arthritis (RA), and 15 from mixed connective tissue disease (MCTD). Clinical and radiographic oral health status was recorded and salivary flow rates were measured. Selected salivary proteins and immunoglobulins were analysed by routine methods. Minor salivary gland biopsy samples were taken from the patients for assessment of inflammatory focus scores. Differences between patients and controls and in between the different rheumatic diseases were analysed statistically. Secondary SS was diagnosed in 39% (30/77) of the patients. A severe periodontal condition (community periodontal index of treatment needs score 3 or 4) occurred in 58% (45/77) of the rheumatic patients compared with only 26% (20/77) of the controls (p < 0.0001). The severity of focal sialadenitis (focus score) correlated significant with salivary IgA, IgG, and IgM concentrations. Salivary albumin, total protein, IgG, and IgM concentrations were higher in all patient groups than in the controls. The number of patients with low salivary flow rates was higher in all patient groups compared to controls. Oral yeast counts were significantly higher in the patients than in the controls (p < 0.001). In a subgroup analysis, patients with SS had higher values for salivary IgA and IgM than patients without SS. Dental caries and oral lactobacilli were more frequent in patients with SS, but SS was not associated with periodontitis. No major differences were noted in other salivary biochemical parameters between these two groups. Patients with rheumatic diseases, irrespective of specific diagnosis, thus had various alterations in salivary flow and composition and oral health. The findings may reflect the autoimmune inflammation of the salivary glands frequently observed in these patients.

Nonopsonic phagocytosis of Bacillus cereus by human polymorphonuclear leukocytes (PMNs) with particular attention to bacterial surface properties and structure was studied. Two reference strains (ATCC 14579T and ATCC 4342) and two clinical isolates (OH599 and OH600) from periodontal and endodontic infections were assessed for adherence to matrix proteins, such as type I collagen, fibronectin, laminin, and fibrinogen. One-day-old cultures of strains OH599 and OH600 were readily ingested by PMNs in the absence of opsonins, while cells from 6-day-old cultures were resistant. Both young and old cultures of the reference strains of B. cereus were resistant to PMN ingestion. Preincubation of PMNs with the phagocytosis-resistant strains of B. cereus did not affect the phagocytosis of the sensitive strain. Negatively stained cells of OH599 and OH600 studied by electron microscopy had a crystalline protein layer on the cell surface. In thin-sectioned cells of older cultures (3 to 6 days old), the S-layer was observed to peel off from the cells. No S-layer was detected on the reference strains. Extraction of cells with detergent followed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed a major 97-kDa protein from the strains OH599 and OH600 but only a weak 97-kDa band from the reference strain ATCC 4342. One-day-old cultures of the clinical strains (hydrophobicity, 5.9 to 6.0%) showed strong binding to type I collagen, laminin, and fibronectin. In contrast, reference strains (hydrophobicity, −1.0 to 4.2%) as well as 6-day-old cultures of clinical strains (hydrophobicity, 19.0 to 53.0%) bound in only low numbers to the proteins. Gold-labelled biotinylated fibronectin was localized on the S-layer on the cell surface as well as on fragments of S-layer peeling off the cells of a 6-day-old culture of B. cereus OH599. Lactose, fibronectin, laminin, and antibodies against the S-protein reduced binding to laminin but not to fibronectin. Heating the cells at 84°C totally abolished binding to both proteins. Benzamidine, a noncompetitive serine protease inhibitor, strongly inhibited binding to fibronectin whereas binding to laminin was increased. Overall, the results indicate that changes in the surface structure, evidently involving the S-layer, during growth of the clinical strains of B. cereus cause a shift from susceptibility to PMN ingestion and strong binding to matrix and basement membrane proteins. Furthermore, it seems that binding to laminin is mediated by the S-protein while binding to fibronectin is dependent on active protease evidently attached to the S-layer.