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Svensäter, G. & Rohlin, M. (2023). An assessment model blending formative and summative assessments using the SOLO taxonomy. European journal of dental education, 27(1), 149-157
Open this publication in new window or tab >>An assessment model blending formative and summative assessments using the SOLO taxonomy
2023 (English)In: European journal of dental education, ISSN 1396-5883, E-ISSN 1600-0579, Vol. 27, no 1, p. 149-157Article in journal (Refereed) Published
Abstract [en]

INTRODUCTION: Formative assessment with emphasis on feedback has been linked to developmental purposes of assessment, whilst summative assessment is assumed to focus on judgemental and quality assurance purposes. This dichotomy is questioned but designs to blend formative and summative assessments in constructive ways are rare in health care education.

METHODS: We have designed an assessment model blending formative and summative assessments . In the formative assessment at the end of a course, students' responses to real-life scenarios with questions demanding responses at the relational level of understanding were assessed at three levels of understanding (incorrect, descriptive, and relational) modified after the SOLO taxonomy. Students were presented with individual feedback for each response. At the summative assessment of a subsequent course, the students' new responses were assessed underpinning a final judgement of students' performance. The assessment model was justified across three student cohorts.

RESULTS: Both formative and summative assessment events of the model provided information about the levels of understanding, unique to each student. A comparison of results from the assessments demonstrated that most responses developed to a higher level of understanding. With the summative assessment it was possible to make judgements about whether or not individual students passed the pre-set standards.

CONCLUSIONS: We argue that the current assessment model presents real interdependence between formative and summative assessments and can provide information that meets the needs of students as learners, education institutes, and health care organisations. The SOLO taxonomy can be used to emphasise the importance of developing and assessing cognitive complexity.

Place, publisher, year, edition, pages
John Wiley & Sons, 2023
Keywords
SOLO taxonomy, assessment, dental education, feedback, learning, understanding
National Category
Dentistry Didactics
Identifiers
urn:nbn:se:mau:diva-50052 (URN)10.1111/eje.12787 (DOI)000761539300001 ()35132742 (PubMedID)2-s2.0-85125418895 (Scopus ID)
Available from: 2022-02-09 Created: 2022-02-09 Last updated: 2024-02-05Bibliographically approved
Leo, F., Svensäter, G., Lood, R. & Wickström, C. (2023). Characterization of a highly conserved MUC5B-degrading protease, MdpL, from Limosilactobacillus fermentum. Frontiers in Microbiology, 14, Article ID 1127466.
Open this publication in new window or tab >>Characterization of a highly conserved MUC5B-degrading protease, MdpL, from Limosilactobacillus fermentum
2023 (English)In: Frontiers in Microbiology, E-ISSN 1664-302X, Vol. 14, article id 1127466Article in journal (Refereed) Published
Abstract [en]

MUC5B is the predominant glycoprotein in saliva and is instrumental in the establishment and maintenance of multi-species eubiotic biofilms in the oral cavity. Investigations of the aciduric Lactobacillaceae family, and its role in biofilms emphasizes the diversity across different genera of the proteolytic systems involved in the nutritional utilization of mucins. We have characterized a protease from Limosilactobacillus fermentum, MdpL (Mucin degrading protease from Limosilactobacillus) with a high protein backbone similarity with commensals that exploit mucins for attachment and nutrition. MdpL was shown to be associated with the bacterial cell surface, in close proximity to MUC5B, which was sequentially degraded into low molecular weight fragments. Mapping the substrate preference revealed multiple hydrolytic sites of proteins with a high O-glycan occurrence, although hydrolysis was not dependent on the presence of O-glycans. However, since proteolysis of immunoglobulins was absent, and general protease activity was low, a preference for glycoproteins similar to MUC5B in terms of glycosylation and structure is suggested. MdpL preferentially hydrolyzed C-terminally located hydrophobic residues in peptides larger than 20 amino acids, which hinted at a limited sequence preference. To secure proper enzyme folding and optimal conditions for activity, L. fermentum incorporates a complex system that establishes a reducing environment. The importance of overall reducing conditions was confirmed by the activity boosting effect of the added reducing agents L-cysteine and DTT. High activity was retained in low to neutral pH 5.5-7.0, but the enzyme was completely inhibited in the presence of Zn2+. Here we have characterized a highly conserved mucin degrading protease from L. fermentum. MdpL, that together with the recently discovered O-glycanase and O-glycoprotease enzyme groups, increases our understanding of mucin degradation and complex biofilm dynamics.

Place, publisher, year, edition, pages
Frontiers Media S.A., 2023
Keywords
MUC5B, Limosilactobacillus fermentum, O-glycan, oral microbiota, mucin degradation, protease
National Category
Biochemistry and Molecular Biology
Identifiers
urn:nbn:se:mau:diva-59286 (URN)10.3389/fmicb.2023.1127466 (DOI)000948293900001 ()36925480 (PubMedID)2-s2.0-85150177439 (Scopus ID)
Available from: 2023-04-19 Created: 2023-04-19 Last updated: 2024-01-17Bibliographically approved
Neilands, J., Svensäter, G., Boisen, G., Robertsson, C., Wickström, C. & Davies, J. R. (2023). Formation and Analysis of Mono-species and Polymicrobial Oral Biofilms in Flow-Cell Models. In: Bacterial Pathogenesis: Methods and Protocols, (pp. 33-52). Springer
Open this publication in new window or tab >>Formation and Analysis of Mono-species and Polymicrobial Oral Biofilms in Flow-Cell Models
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2023 (English)In: Bacterial Pathogenesis: Methods and Protocols,, Springer, 2023, p. 33-52Chapter in book (Refereed)
Abstract [en]

The oral microbiota, which is known to include at least 600 different bacterial species, is found on the teethand mucosal surfaces as multi-species communities or biofilms. The oral surfaces are covered with a pellicleof proteins absorbed from saliva, and biofilm formation is initiated when primary colonizers, which expresssurface adhesins that bind to specific salivary components, attach to the oral tissues. Further developmentthen proceeds through co-aggregation of additional species. Over time, the composition of oral biofilms,which varies between different sites throughout the oral cavity, is determined by a combination ofenvironmental factors such as the properties of the underlying surface, nutrient availability and oxygenlevels, and bacterial interactions within the community. A complex equilibrium between biofilm communities and the host is responsible for the maintenance of a healthy biofilm phenotype (eubiosis). In the faceof sustained environmental perturbation, however, biofilm homeostasis can break down giving rise todysbiosis, which is associated with the development of oral diseases such as caries and periodontitis.In vitro models have an important part to play in increasing our understanding of the complex processesinvolved in biofilm development in oral health and disease, and the requirements for experimental system,microbial complexity, and analysis techniques will necessarily vary depending on the question posed. In thischapter we describe some current and well-established methods used in our laboratory for studying oralbacteria in biofilm models which can be adapted to suit the needs of individual users. 

Place, publisher, year, edition, pages
Springer, 2023
Series
Methods in Molecular Biology, E-ISSN 1940-6029 ; 2674
National Category
Cell and Molecular Biology
Identifiers
urn:nbn:se:mau:diva-62874 (URN)10.1007/978-1-0716-3243-7_2 (DOI)37258958 (PubMedID)2-s2.0-85160680476 (Scopus ID)978-1-0716-3242-0 (ISBN)978-1-0716-3243-7 (ISBN)
Available from: 2023-09-29 Created: 2023-09-29 Last updated: 2023-10-06Bibliographically approved
Hix Janssens, T., Shinde, S., Abouhany, R., Davies, J. R., Neilands, J., Svensäter, G. & Sellergren, B. (2023). Microcontact-Imprinted Optical Sensors for Virulence Factors of Periodontal Disease. ACS Omega, 8(17), 15259-15265
Open this publication in new window or tab >>Microcontact-Imprinted Optical Sensors for Virulence Factors of Periodontal Disease
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2023 (English)In: ACS Omega, E-ISSN 2470-1343, Vol. 8, no 17, p. 15259-15265Article in journal (Refereed) Published
Abstract [en]

Periodontitis (gum disease) is a common biofilm-mediated oral condition, with around 7% of the adult population suffering from severe disease with risk for tooth loss. Moreover, periodontitis virulence markers have been found in atherosclerotic plaque and brain tissue, suggesting a link to cardiovascular and Alzheimer’s diseases. The lack of accurate, fast, and sensitive clinical methods to identify patients at risk leads, on the one hand, to patients being undiagnosed until the onset of severe disease and, on the other hand, to overtreatment of individuals with mild disease, diverting resources from those patients most in need. The periodontitis-associated bacterium, Porphyromonas gingivalis, secrete gingipains which are highly active proteases recognized as key virulence factors during disease progression. This makes them interesting candidates as predictive biomarkers, but currently, there are no methods in clinical use for monitoring them. Quantifying the levels or proteolytic activity of gingipains in the periodontal pocket surrounding the teeth could enable early-stage disease diagnosis. Here, we report on a monitoring approach based on high-affinity microcontact imprinted polymer-based receptors for the Arg and Lys specific gingipains Rgp and Kgp and their combination with surface plasmon resonance (SPR)-based biosensor technology for quantifying gingipain levels in biofluids and patient samples. Therefore, Rgp and Kgp were immobilized on glass coverslips followed by microcontact imprinting of poly-acrylamide based films anchored to gold sensor chips. The monomers selected were N-isopropyl acrylamide (NIPAM), N-hydroxyethyl acrylamide (HEAA) and N-methacryloyl-4-aminobenzamidine hydrochloride (BAM), with N,N′-methylene bis(acrylamide) (BIS) as the crosslinker. This resulted in imprinted surfaces exhibiting selectivity towards their templates high affinity and selectivity for the templated proteins with dissociation constants (Kd) of 159 and 299 nM for the Rgp- and Kgp-imprinted, surfaces respectively. The former surface displayed even higher affinity (Kd = 71 nM) when tested in dilute cell culture supernatants. Calculated limits of detection for the sensors were 110 and 90 nM corresponding to levels below clinically relevant concentrations.

Place, publisher, year, edition, pages
American Chemical Society (ACS), 2023
National Category
Dentistry Medical Biotechnology
Identifiers
urn:nbn:se:mau:diva-59511 (URN)10.1021/acsomega.3c00389 (DOI)000978106200001 ()37151489 (PubMedID)2-s2.0-85154067619 (Scopus ID)
Available from: 2023-05-15 Created: 2023-05-15 Last updated: 2023-08-15Bibliographically approved
Havsed, K., Hänsel Petersson, G., Isberg, P.-E., Pigg, M., Svensäter, G. & Rohlin, M. (2023). Multivariable prediction models of caries increment: a systematic review and critical appraisal.. Systematic Reviews, 12(1), Article ID 202.
Open this publication in new window or tab >>Multivariable prediction models of caries increment: a systematic review and critical appraisal.
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2023 (English)In: Systematic Reviews, E-ISSN 2046-4053, Vol. 12, no 1, article id 202Article in journal (Refereed) Published
Abstract [en]

BACKGROUND: Multivariable prediction models are used in oral health care to identify individuals with an increased likelihood of caries increment. The outcomes of the models should help to manage individualized interventions and to determine the periodicity of service. The objective was to review and critically appraise studies of multivariable prediction models of caries increment.

METHODS: Longitudinal studies that developed or validated prediction models of caries and expressed caries increment as a function of at least three predictors were included. PubMed, Cochrane Library, and Web of Science supplemented with reference lists of included studies were searched. Two reviewers independently extracted data using CHARMS (Critical Appraisal and Data Extraction for Systematic Reviews of Prediction Modelling Studies) and assessed risk of bias and concern regarding applicability using PROBAST (Prediction model Risk Of Bias ASessment Tool). Predictors were analysed and model performance was recalculated as estimated positive (LR +) and negative likelihood ratios (LR -) based on sensitivity and specificity presented in the studies included.

RESULTS: Among the 765 reports identified, 21 studies providing 66 prediction models fulfilled the inclusion criteria. Over 150 candidate predictors were considered, and 31 predictors remained in studies of final developmental models: caries experience, mutans streptococci in saliva, fluoride supplements, and visible dental plaque being the most common predictors. Predictive performances varied, providing LR + and LR - ranges of 0.78-10.3 and 0.0-1.1, respectively. Only four models of coronal caries and one root caries model scored LR + values of at least 5. All studies were assessed as having high risk of bias, generally due to insufficient number of outcomes in relation to candidate predictors and considerable uncertainty regarding predictor thresholds and measurements. Concern regarding applicability was low overall.

CONCLUSIONS: The review calls attention to several methodological deficiencies and the significant heterogeneity observed across the studies ruled out meta-analyses. Flawed or distorted study estimates lead to uncertainty about the prediction, which limits the models' usefulness in clinical decision-making. The modest performance of most models implies that alternative predictors should be considered, such as bacteria with acid tolerant properties.

TRIAL REGISTRATION: PROSPERO CRD#152,467 April 28, 2020.

Place, publisher, year, edition, pages
BioMed Central (BMC), 2023
Keywords
CHARMS, Dental caries, Likelihood ratio, PROBAST, Prediction models
National Category
Dentistry
Identifiers
urn:nbn:se:mau:diva-63663 (URN)10.1186/s13643-023-02298-y (DOI)001089824700001 ()37904228 (PubMedID)2-s2.0-85175349690 (Scopus ID)
Available from: 2023-11-13 Created: 2023-11-13 Last updated: 2023-12-04Bibliographically approved
Robertsson, C., Svensäter, G., Davies, J. R., Bay Nord, A., Malmodin, D. & Wickström, C. (2023). Synergistic metabolism of salivary MUC5B in oral commensal bacteria during early biofilm formation. Microbiology Spectrum, 11(6)
Open this publication in new window or tab >>Synergistic metabolism of salivary MUC5B in oral commensal bacteria during early biofilm formation
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2023 (English)In: Microbiology Spectrum, E-ISSN 2165-0497, Vol. 11, no 6Article in journal (Refereed) Published
Abstract [en]

Bacterial metabolism in oral biofilms is comprised of complex networks of nutritional chains and biochemical regulations. These processes involve both intraspecies and interspecies networks as well as interactions with components from host saliva, gingival crevicular fluid, and dietary intake. In a previous paper, a large salivary glycoprotein, mucin MUC5B, was suggested to promote a dental health-related phenotype in the oral type strain of Streptococcus gordonii DL1, by regulating bacterial adhesion and protein expression. In this study, nuclear magnetic resonance-based metabolomics was used to examine the effects on the metabolic output of monospecies compared to dual species early biofilms of two clinical strains of oral commensal bacteria, S. gordonii and Actinomyces naeslundii, in the presence of MUC5B. The presence of S. gordonii increased colonization of A. naeslundii on salivary MUC5B, and both commensals were able to utilize MUC5B as a sole nutrient source during early biofilm formation. The metabolomes suggested that the bacteria were able to release mucin carbohydrates from oligosaccharide side chains as well as amino acids from the protein core. Synergistic effects were also seen in the dual species biofilm metabolome compared to the monospecies, indicating that A. naeslundii and S. gordonii cooperated in the degradation of salivary MUC5B. A better understanding of bacterial interactions and salivary-mediated regulation of early dental biofilm activity is meaningful for understanding oral biofilm physiology and may contribute to the development of future prevention strategies for biofilm-induced oral disease.

IMPORTANCE: The study of bacterial interactions and salivary-mediated regulation of early dental biofilm activity is of interest for understanding oral microbial adaptation to environmental cues and biofilm maturation. Findings in oral commensals can prove useful from the perspectives of both oral and systemic health of the host, as well as the understanding of general microbial biofilm physiology. The knowledge may provide a basis for the development of prognostic biomarkers, or development of new treatment strategies, related to oral health and disease and possibly also to other biofilm-induced conditions. The study is also an important step toward developing the methodology for similar studies in other species and/or growth conditions.

Place, publisher, year, edition, pages
ASM International, 2023
Keywords
MUC5B, NMR, actinomyces, bacterial metabolism, biofilm physiology, dental biofilm, metabolomics, oral microbiology, saliva, streptococci
National Category
Dentistry
Identifiers
urn:nbn:se:mau:diva-63213 (URN)10.1128/spectrum.02704-23 (DOI)001085549500001 ()37855449 (PubMedID)2-s2.0-85180007534 (Scopus ID)
Available from: 2023-10-23 Created: 2023-10-23 Last updated: 2024-01-10Bibliographically approved
Lima, B. P., Davies, J. R., Wickström, C., Johnstone, K. F., Hall, J. W., Svensäter, G. & Herzberg, M. C. (2022). Streptococcus gordonii Poised for Glycan Feeding through a MUC5B-Discriminating, Lipoteichoic Acid-Mediated Outside-In Signaling Circuit. Journal of Bacteriology, 204(6), Article ID e00118-22.
Open this publication in new window or tab >>Streptococcus gordonii Poised for Glycan Feeding through a MUC5B-Discriminating, Lipoteichoic Acid-Mediated Outside-In Signaling Circuit
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2022 (English)In: Journal of Bacteriology, ISSN 0021-9193, E-ISSN 1098-5530, Vol. 204, no 6, article id e00118-22Article in journal (Refereed) Published
Abstract [en]

Many oral bacteria employ cell wall-anchored adhesins to bind to the salivary films coating the teeth and mucosal surfaces. Surface binding prevents clearance and facilitates catabolism of salivary film glycoproteins. We asked whether Streptococcus gordonii adhesin expression changes in response to surface salivary cues using a eukaryote-like, outside-in recognition and signaling circuit. To determine whether the cues were discriminated, S. gordonii was tested during cell adhesion and biofilm formation on a MUC5B-rich or lower-molecular-mass salivary fraction or an uncoated abiotic surface. Cells were recovered and analyzed for differences in gene expression and proteins in cell wall fractions. In salivary-free conditions, planktonic S. gordonii presented three prominent cell wall LPXTG-motif proteins, SGO_1487, SGO_0890, and MbpA (mucin-binding protein A; SGO_0707). During biofilm formation on MUC5B-coated surfaces, MbpA, a MUC5B-binding protein, and key genes in the tagatose and quorum-sensing pathways were strongly promoted. The response to MUC5B required the two-component system (TCS), streptococcal regulator of adhesins sensor and regulator (SraSR, SGO_1180/81), lipoteichoic acid (LTA), and the homologous paired adhesins, SspA and SspB (SspAB). LTA appears to link the outside signal (MUC5B) to intramembrane SraSR. Tagatose pathway gene expression may poise cells to metabolize MUC5B glycans and, with a quorum-sensing gene (luxS), may direct formation of a consortium to facilitate glycan cross-feeding by S. gordonii. We now show that a Gram-positive bacterium discriminates specific surface environmental cues using an outside-in signaling mechanism to apparently optimize colonization of saliva-coated surfaces. IMPORTANCE All organisms throughout the tree of life sense and respond to their surface environments. To discriminate among mucosal surface environmental cues, we report that Streptococcus gordonii recognizes a high-molecular-weight mucin glycoprotein, MUC5B, using the paired adhesins SspAB and lipoteichoic acid; the latter bridges the outside signal to an intramembrane two-component system to transcriptionally regulate a MUC5B-specific adhesin and genes that may facilitate glycan catabolism. All organisms throughout the tree of life sense and respond to their surface environments. To discriminate among mucosal surface environmental cues, we report that Streptococcus gordonii recognizes a high-molecular-weight mucin glycoprotein, MUC5B, using the paired adhesins SspAB and lipoteichoic acid; the latter bridges the outside signal to an intramembrane two-component system to transcriptionally regulate a MUC5B-specific adhesin and genes that may facilitate glycan catabolism.

Place, publisher, year, edition, pages
ASM International, 2022
Keywords
Streptococcus gordonii, signaling circuit, glycan feeding, MUC5B, adhesins, lipoteichoic acid, two-component system
National Category
Dentistry
Identifiers
urn:nbn:se:mau:diva-53384 (URN)10.1128/jb.00118-22 (DOI)000809024700001 ()35652671 (PubMedID)2-s2.0-85132455432 (Scopus ID)
Available from: 2022-06-22 Created: 2022-06-22 Last updated: 2024-02-05Bibliographically approved
Alshammari, H., Neilands, J., Svensäter, G. & Stavropoulos, A. (2021). Antimicrobial Potential of Strontium Hydroxide on Bacteria Associated with Peri-Implantitis. Antibiotics, 10(2), Article ID 150.
Open this publication in new window or tab >>Antimicrobial Potential of Strontium Hydroxide on Bacteria Associated with Peri-Implantitis
2021 (English)In: Antibiotics, ISSN 0066-4774, E-ISSN 2079-6382, Vol. 10, no 2, article id 150Article in journal (Refereed) Published
Abstract [en]

Background: Peri-implantitis due to infection of dental implants is a common complication that may cause significant patient morbidity. In this study, we investigated the antimicrobial potential of Sr(OH)2 against different bacteria associated with peri-implantitis. Methods: The antimicrobial potential of five concentrations of Sr(OH)2 (100, 10, 1, 0.1, and 0.01 mM) was assessed with agar diffusion test, minimal inhibitory concentration (MIC), and biofilm viability assays against six bacteria commonly associated with biomaterial infections: Streptococcus mitis, Staphylococcus epidermidis, Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, Escherichia coli, and Fusobacterium nucleatum. Results: Zones of inhibition were only observed for, 0.01, 0.1, and 1 mM of Sr(OH)2 tested against P. gingivalis, in the agar diffusion test. Growth inhibition in planktonic cultures was achieved at 10 mM for all species tested (p < 0.001). In biofilm viability assay, 10 and 100 mM Sr(OH)2 showed potent bactericidal affect against S. mitis, S. epidermidis, A. actinomycetemcomitans, E. coli, and P. gingivalis. Conclusions: The findings of this study indicate that Sr(OH)2 has antimicrobial properties against bacteria associated with peri-implantitis. 

Place, publisher, year, edition, pages
MDPI, 2021
Keywords
antimicrobial, bacteria, peri-implantitis, strontium
National Category
Dentistry
Identifiers
urn:nbn:se:mau:diva-41149 (URN)10.3390/antibiotics10020150 (DOI)000622033700001 ()33546189 (PubMedID)2-s2.0-85100658878 (Scopus ID)
Available from: 2021-03-10 Created: 2021-03-10 Last updated: 2024-02-05Bibliographically approved
Havsed, K., Stensson, M., Jansson, H., Carda-Diéguez, M., Pedersen, A., Neilands, J., . . . Mira, A. (2021). Bacterial Composition and Metabolomics of Dental Plaque From Adolescents. Frontiers in Cellular and Infection Microbiology, 11, Article ID 716493.
Open this publication in new window or tab >>Bacterial Composition and Metabolomics of Dental Plaque From Adolescents
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2021 (English)In: Frontiers in Cellular and Infection Microbiology, E-ISSN 2235-2988, Vol. 11, article id 716493Article in journal (Refereed) Published
Abstract [en]

Supragingival dental plaque samples were collected from 40 Swedish adolescents, including 20 with caries lesions (CAR) and 20 caries-free (CF). Fresh plaque samples were subjected to an ex vivo acid tolerance (AT) test where the proportion of bacteria resistant to an acid shock was evaluated through confocal microscopy and live/dead staining, and the metabolites produced were quantified by 1H Nuclear Magnetic Resonance (1H NMR). In addition, DNA was extracted and the 16S rRNA gene was sequenced by Illumina sequencing, in order to characterize bacterial composition in the same samples. There were no significant differences in AT scores between CAR and CF individuals. However, 7 out of the 10 individuals with highest AT scores belonged to the CAR group. Regarding bacterial composition, Abiotrophia, Prevotella and Veillonella were found at significantly higher levels in CAR individuals (p=0.0085, 0.026 and 0.04 respectively) and Rothia and Corynebacterium at significantly higher levels in CF individuals (p=0.026 and 0.003). The caries pathogen Streptococcus mutans was found at low frequencies and was absent in 60% of CAR individuals. Random-forest predictive models indicate that at least 4 bacterial species or 9 genera are needed to distinguish CAR from CF adolescents. The metabolomic profile obtained by NMR showed a significant clustering of organic acids with specific bacteria in CAR and/or high AT individuals, being Scardovia wiggsiae the species with strongest associations. A significant clustering of ethanol and isopropanol with health-associated bacteria such as Rothia or Corynebacterium was also found. Accordingly, several relationships involving these compounds like the Ethanol : Lactate or Succinate : Lactate ratios were significantly associated to acid tolerance and could be of predictive value for caries risk. We therefore propose that future caries risk studies would benefit from considering not only the use of multiple organisms as potential microbial biomarkers, but also their functional adaptation and metabolic output.

Place, publisher, year, edition, pages
Frontiers Media S.A., 2021
Keywords
NMR, Rothia, Streptococcus mutans (S. mutans), acid tolerance, caries risk (assessment), dental caries, metabolomics (OMICS), microbiome
National Category
Dentistry
Identifiers
urn:nbn:se:mau:diva-44983 (URN)10.3389/fcimb.2021.716493 (DOI)000684641700001 ()34395316 (PubMedID)2-s2.0-85112476194 (Scopus ID)
Available from: 2021-08-20 Created: 2021-08-20 Last updated: 2024-02-05Bibliographically approved
Davies, J. R., Kad, T., Neilands, J., Kinnby, B., Prgomet, Z., Bengtsson, T., . . . Svensäter, G. (2021). Polymicrobial synergy stimulates Porphyromonas gingivalis survival and gingipain expression in a multi-species subgingival community.. BMC Oral Health, 21(1), Article ID 639.
Open this publication in new window or tab >>Polymicrobial synergy stimulates Porphyromonas gingivalis survival and gingipain expression in a multi-species subgingival community.
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2021 (English)In: BMC Oral Health, ISSN 1472-6831, E-ISSN 1472-6831, Vol. 21, no 1, article id 639Article in journal (Refereed) Published
Abstract [en]

BACKGROUND: Dysbiosis in subgingival microbial communities, resulting from increased inflammatory transudate from the gingival tissues, is an important factor in initiation and development of periodontitis. Dysbiotic communities are characterized by increased numbers of bacteria that exploit the serum-like transudate for nutrients, giving rise to a proteolytic community phenotype. Here we investigate the contribution of interactions between members of a sub-gingival community to survival and development of virulence in a serum environment-modelling that in the subgingival pocket.

METHODS: Growth and proteolytic activity of three Porphyromonas gingivalis strains in nutrient broth or a serum environment were assessed using A600 and a fluorescent protease substrate, respectively. Adherence of P. gingivalis strains to serum-coated surfaces was studied with confocal microscopy and 2D-gel electrophoresis of bacterial supernatants used to investigate extracellular proteins. A model multi-species sub-gingival community containing Fusobacterium nucleatum, Streptococcus constellatus, Parvimonas micra with wild type or isogenic mutants of P. gingivalis was then created and growth and proteolytic activity in serum assessed as above. Community composition over time was monitored using culture techniques and qPCR.

RESULTS: The P. gingivalis strains showed different growth rates in nutrient broth related to the level of proteolytic activity (largely gingipains) in the cultures. Despite being able to adhere to serum-coated surfaces, none of the strains was able to grow alone in a serum environment. Together in the subgingival consortium however, all the included species were able to grow in the serum environment and the community adopted a proteolytic phenotype. Inclusion of P. gingivalis strains lacking gingipains in the consortium revealed that community growth was facilitated by Rgp gingipain from P. gingivalis.

CONCLUSIONS: In the multi-species consortium, growth was facilitated by the wild-type and Rgp-expressing strains of P. gingivalis, suggesting that Rgp is involved in delivery of nutrients to the whole community through degradation of complex protein substrates in serum. Whereas they are constitutively expressed by P. gingivalis in nutrient broth, gingipain expression in the model periodontal pocket environment (serum) appeared to be orchestrated through signaling to P. gingivalis from other members of the community, a phenomenon which then promoted growth of the whole community.

Place, publisher, year, edition, pages
BioMed Central, 2021
Keywords
Dysbiosis, Microbial community, Periodontitis, Proteolytic activity, Virulence
National Category
Dentistry
Identifiers
urn:nbn:se:mau:diva-49063 (URN)10.1186/s12903-021-01971-9 (DOI)000730556300002 ()34911531 (PubMedID)2-s2.0-85121339809 (Scopus ID)
Available from: 2021-12-29 Created: 2021-12-29 Last updated: 2024-02-05Bibliographically approved
Projects
Bacterial acid tolerance – a new target for fluoridated milk; Malmö UniversityBiomarkers and biotherapeutics for polymicrobial infections and inflammation; Malmö University, Faculty of Odontology (OD)Lipoprotein modifications by periodontal pathogens; Malmö University, Biofilms Research Center for BiointerfacesRegulation of Surface Protein - Presentation on Streptococcus gordonii
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0003-3173-7577

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