| 1. |
- Fröjd, Victoria, 1986, et al.
(författare)
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In situ analysis of multispecies biofilm formation on customized titanium surfaces
- 2011
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Ingår i: Molecular Oral Microbiology. - : John Wiley & Sons. - 2041-1006 .- 2041-1014. ; 26:4, s. 241-252
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Tidskriftsartikel (refereegranskat)abstract
- Many studies to identify surfaces that enhance the incorporation of dental implants into bone and soft-tissue have been undertaken previously. However, to succeed in the clinical situation, an implant surface must not support development of microbial biofilms with a pathogenic potential. As a first step in investigating this, we used two-species and three-species biofilm models with 16S ribosomal RNA fluorescence in situ hybridization and confocal laser scanning microscopy to examine the effect of surface characteristics on biofilm formation by species that can colonize titanium implants in vivo: Streptococcus sanguinis, Actinomyces naeslundii and Lactobacillus salivarius. Surfaces blasted with Al(2) O(3) (S(a) = 1.0-2.0 μm) showed a seven-fold higher bacterial adhesion after 2 h than turned surfaces (S(a) = 0.18 μm) whereas porous surfaces, generated by anodic oxidation (S(a) = 0.4 μm), showed four-fold greater adhesion than turned surfaces. Hence, increased roughness promoted adhesion, most likely through protection of bacteria from shear forces. Chemical modification of the blasted and oxidized surfaces by incorporation of Ca(2+) ions reduced adhesion compared with the corresponding non-modified surfaces. After 14 h, biofilm growth occurred in the three-species model but not in the two-species consortium (containing S. sanguinis and A. naeslundii only). The biofilm biovolume on all surfaces was similar, suggesting that the influence of surface characteristics on adhesion was compensated for by biofilm development.
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| 2. |
- Kindblom, Christian, et al.
(författare)
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Salivary proteins promote proteolytic activity in Streptococcus mitis biovar 2 and Streptococcus mutans
- 2012
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Ingår i: Molecular Oral Microbiology. - : John Wiley & Sons. - 2041-1006 .- 2041-1014. ; 27:5, s. 362-372
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Tidskriftsartikel (refereegranskat)abstract
- A major function of the salivary pellicle on oral surfaces is to promote colonization of the commensal microbiota by providing binding sites for adherence. Streptococcus mitis is an early colonizer of the oral cavity whereas Streptococcus mutans represents a later colonizer. To survive and grow, oral bacteria produce enzymes, proteases and glycosidases, which allow them to exploit salivary proteins as a nutrient source. In this study, adherence and proteolytic activity of S. mitis biovar 2 and S. mutans were investigated in a flow-cell model in the presence of different populations of surface-associated salivary proteins. Streptococcus mitis biovar 2 adhered well to surfaces coated with both a MUC5B-enriched fraction and a pool of low-density proteins containing MUC7, amylase, cystatin, gp340, immunoglobulin A, lactoferrin, lysozyme and statherin, whereas adherence of S. mutans to these proteins was poor. In environments of MUC5B or the low-density proteins, both S. mitis biovar 2 and S. mutans showed high levels of proteolytic activity. For S. mitis in the MUC5B environment, most of this activity may be attributable to contact with the molecules in the fluid phase although activity was also enhanced by adherence to surface-associated MUC5B. These data suggest that although they differ in their capacity to adhere to surface-associated salivary proteins, in the natural environment exploitation of saliva as a nutrient source can contribute to survival and colonization of the oral cavity by both S. mitis biovar 2 and S. mutans.
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| 3. |
- Piwat, S, et al.
(författare)
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Lactobacillus species and genotypes associated with dental caries in Thai preschool children.
- 2010
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Ingår i: Molecular oral microbiology. - : Wiley. - 2041-1014 .- 2041-1006. ; 25:2, s. 157-64
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Tidskriftsartikel (refereegranskat)abstract
- Lactobacilli have been associated with the presence and progression of dental caries. Nevertheless, the relation between certain species or genotypes of Lactobacillus and caries is unclear and there are no data available for the Thai population. This study aimed to examine the distribution of species and genotypes of oral Lactobacillus among children with rather high caries prevalence, and to investigate whether certain species or genotypes were more related to caries activity than others. One hundred and sixty-five children were examined for caries status. Saliva samples were collected and the numbers of lactobacilli were counted. A total of 357 Lactobacillus isolates from 59 children were identified to species level by 16S ribosomal RNA genes polymerase chain reaction (PCR) -restriction fragment length polymorphism and 16S ribosomal RNA gene sequencing. Furthermore, 304 isolates from 56 children were genotyped using arbitrarily primed PCR. Significant correlation was found between levels of lactobacilli and dental caries (P < 0.001). Among the 10 identified species of Lactobacillus, L. salivarius was more prevalent in children with moderate to high caries prevalence compared with children with low caries prevalence, while L. fermentum was the most predominant species in all study groups. Moreover, a genetic heterogeneity of Lactobacillus species was found among the children and those with high caries prevalence tended to be colonized with more than one clonal type. In summary, L. salivarius may be a putative caries pathogen among preschool Thai children.
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| 4. |
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| 5. |
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| 6. |
- Bostanci, N, et al.
(författare)
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Tribute
- 2016
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Ingår i: Molecular oral microbiology. - : Wiley. - 2041-1014 .- 2041-1006. ; 31:3, s. 205-206
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Tidskriftsartikel (refereegranskat)
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| 7. |
- Eckert, M., et al.
(författare)
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In vivo expression of proteases and protease inhibitor, a serpin, by periodontal pathogens at teeth and implants
- 2018
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Ingår i: Molecular Oral Microbiology. - : John Wiley & Sons. - 2041-1006 .- 2041-1014. ; 33:3, s. 240-248
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Tidskriftsartikel (refereegranskat)abstract
- Porphyromonas gingivalis and Tannerella forsythia secrete proteases, gingipains and KLIKK-proteases. In addition, T.forsythia produces a serpin (miropin) with broad inhibitory spectrum. The aim of this pilot study was to determine the level of expression of miropin and individual proteases in vivo in periodontal and peri-implant health and disease conditions. Biofilm and gingival crevicular fluid (GCF)/ peri-implant sulcular fluid (PISF) samples were taken from healthy tooth and implant sites (n = 10), gingivitis and mucositis sites (n = 12), and periodontitis and peri-implantitis sites (n = 10). Concentration of interleukin-8 (IL-8), IL-1 beta and IL-10 in GCF was determined by enzyme-linked immunosorbent assay. Loads of P.gingivalis and T.forsythia and the presence of proteases and miropin genes were assessed in biofilm by quantitative PCR, whereas gene expression was estimated by quantitative RT-PCR. The presence of P.gingivalis and T.forsythia, as well as the level of IL-8 and IL-1, were associated with disease severity in the periodontal and peri-implant tissues. In biofilm samples harboring T.forsythia, genes encoding proteases were found to be present at 72.4% for karilysin and 100% for other KLIKK-protease genes and miropin. At the same time, detectable mRNA expression of individual genes ranged from 20.7% to 58.6% of samples (for forsylisin and miropsin-1, respectively). In comparison with the T.forsythia proteases, miropin and the gingipains were highly expressed. The level of expression of gingipains was associated with those of miropin and certain T.forsythia proteases around teeth but not implants. Cumulatively, KLIKK-proteases and especially miropin, might play a role in pathogenesis of both periodontal and peri-implant diseases.
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| 8. |
- Jayaprakash, Kartheyaene, 1983-, et al.
(författare)
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The role of phagocytosis, oxidative burst and neutrophil extracellular traps in the interaction between neutrophils and the periodontal pathogen Porphyromonas gingivalis
- 2015
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Ingår i: Molecular Oral Microbiology. - : Wiley. - 2041-1006 .- 2041-1014. ; 30:5, s. 361-375
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Tidskriftsartikel (refereegranskat)abstract
- Neutrophils are regarded as the sentinel cells of innate immunity and are found in abundance within the gingival crevice. Discovery of neutrophil extracellular traps (NETs) within the gingival pockets prompted us to probe the nature of the interactions of neutrophils with the prominent periopathogen Porphyromonas gingivalis. Some of the noted virulence factors of this Gram-negative anaerobe are gingipains: arginine gingipains (RgpA/B) and lysine gingipain (Kgp). The aim of this study was to evaluate the role of gingipains in phagocytosis, formation of reactive oxygen species, NETs and CXCL8 modulation by using wild-type strains and isogenic gingipain mutants. Confocal imaging showed that gingipain mutants K1A (Kgp) and E8 (RgpA/B) induced extracellular traps in neutrophils, whereas ATCC33277 and W50 were phagocytosed. The viability of both ATCC33277 and W50 dwindled as the result of phagocytosis and could be salvaged by cytochalasin D, and the bacteria released high levels of lipopolysaccharide in the culture supernatant. Porphyromonas gingivalis induced reactive oxygen species and CXCL8 with the most prominent effect being that of the wild-type strain ATCC33277, whereas the other wild-type strain W50 was less effective. Quantitative real-time polymerase chain reaction revealed a significant CXCL8 expression by E8. All the tested P.gingivalis strains increased cytosolic free calcium. In conclusion, phagocytosis is the primary neutrophil response to P.gingivalis, although NETs could play an accessory role in infection control. Although gingipains do not seem to directly regulate phagocytosis, NETs or oxidative burst in neutrophils, their proteolytic properties could modulate the subsequent outcomes such as nutrition acquisition and survival by the bacteria.
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| 9. |
- Klarström-Engström, Kristin, 1986-, et al.
(författare)
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The role of Porphyromonas gingivalis gingipains in platelet activation and innate immune modulation
- 2015
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Ingår i: Molecular Oral Microbiology. - : Wiley. - 2041-1006 .- 2041-1014. ; 30:1, s. 62-73
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Tidskriftsartikel (refereegranskat)abstract
- Platelets are considered to have important functions in inflammatory processes and as actors in the innate immunity. Several studies have shown associations between cardiovascular disease and periodontitis, where the oral anaerobic pathogen Porphyromonas gingivalis has a prominent role in modulating the immune response. Porphyromonas gingivalis has been found in atherosclerotic plaques, indicating spreading of the pathogen via the circulation, with an ability to interact with and activate platelets via e.g. Toll-like receptors (TLR) and protease-activated receptors. We aimed to evaluate how the cysteine proteases, gingipains, of P.gingivalis affect platelets in terms of activation and chemokine secretion, and to further investigate the mechanisms of platelet-bacteria interaction. This study shows that primary features of platelet activation, i.e. changes in intracellular free calcium and aggregation, are affected by P.gingivalis and that arg-gingipains are of great importance for the ability of the bacterium to activate platelets. The P.gingivalis induced a release of the chemokine RANTES, however, to a much lower extent compared with the TLR2/1-agonist Pam(3)CSK(4), which evoked a time-dependent release of the chemokine. Interestingly, the TLR2/1-evoked response was abolished by a following addition of viable P.gingivalis wild-types and gingipain mutants, showing that both Rgp and Kgp cleave the secreted chemokine. We also demonstrate that Pam(3)CSK(4)-stimulated platelets release migration inhibitory factor and plasminogen activator inhibitor-1, and that also these responses were antagonized by P.gingivalis. These results supports immune-modulatory activities of P.gingivalis and further clarify platelets as active players in innate immunity and in sensing bacterial infections, and as target cells in inflammatory reactions induced by P.gingivalis infection.
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| 10. |
- Palm, Eleonor, 1980-, et al.
(författare)
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Suppression of inflammatory responses of human gingival fibroblasts by gingipains from Porphyromonas gingivalis
- 2015
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Ingår i: Molecular Oral Microbiology. - : Wiley. - 2041-1006 .- 2041-1014. ; 30:1, s. 74-85
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Tidskriftsartikel (refereegranskat)abstract
- The interaction between human gingival fibroblasts (HGFs) and Porphyromonas gingivalis plays an important role in the development and progression of periodontitis. Porphyromonas gingivalis possesses several virulence factors, including cysteine proteases, the arginine-specific (Rgp) and lysine-specific (Kgp) gingipains. Studying the mechanisms that P.gingivalis, and its derived virulence, use to propagate and interact with host cells will increase the understanding of the development and progression of periodontitis. In this study, we aimed to elucidate how P.gingivalis influences the inflammatory events in HGFs regarding transforming growth factor-(1) (TGF-(1)), CXCL8, secretory leucocyte protease inhibitor (SLPI), c-Jun and indoleamine 2,3-dioxygenase (IDO). HGFs were inoculated for 6 and 24h with the wild-type strains ATCC 33277 and W50, two gingipain-mutants of W50 and heat-killed ATCC 33277. The P.gingivalis regulated CXCL8 and TGF-(1) in HGFs, and the kgp mutant gave significantly higher immune response with increased CXCL8 (P<0.001) and low levels of TGF-(1). We show that HGFs express and secrete SLPI, which was significantly suppressed by P.gingivalis (P<0.05). This suggests that by antagonizing SLPI, P.gingivalis contributes to the tissue destruction associated with periodontitis. Furthermore, we found that P.gingivalis inhibits the expression of the antimicrobial IDO, as well as upregulating c-Jun (P<0.05). In conclusion, P.gingivalis both triggers and suppresses the immune response in HGFs. Consequently, we suggest that the pathogenic effects of P.gingivalis, and especially the activity of the gingipains on the inflammatory and immune response of HGFs, are crucial in periodontitis.
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