A defined five-member oral biofilm model representing early acidogenic stages of the caries process. The community combines Streptococcus oralis, Streptococcus sanguinis, Streptococcus mitis, Streptococcus downei, and Actinomyces naeslundii in flow-channel biofilms to reproduce the composition, architecture, and microscale pH heterogeneity of early dental plaque.
Taxonomy
| Taxon | Ontology ID | Functional Roles | Abundance |
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| Streptococcus oralis | NCBITaxon:1303 · TaxonMech · TraitMech | N/A | |
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| Streptococcus sanguinis | NCBITaxon:1305 · TaxonMech · TraitMech | N/A | |
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| Streptococcus mitis | NCBITaxon:28037 · TaxonMech · TraitMech | N/A | |
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| Streptococcus downei | NCBITaxon:1317 · TaxonMech · TraitMech | N/A | |
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| Actinomyces naeslundii | NCBITaxon:1655 · TaxonMech · TraitMech | N/A | |
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Ecological Interactions
The graph shows only explicitly linked interaction participants. Community members without an asserted participant link are omitted; membership alone does not imply an interaction.
A. naeslundii and S. mitis Planktonic Coaggregation
A. naeslundii AK6 and S. mitis SK24 formed visible coaggregates within 15 min in a separate planktonic assay in 1/10 Todd-Hewitt broth. This is direct physical association, not a demonstrated directional benefit, colonization-facilitation effect or cause of acidification in the five-species biofilm. The authors propose an adhesion contribution but did not selectively perturb coaggregation in the pH assay.
Source Taxon: Actinomyces naeslundii
Target Taxon: Streptococcus mitis
Evidence
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PMID:21966490 - SUPPORT (IN_VITRO)"cells of A. naeslundii AK6 and S. mitis SK24 formed clearly visible, slowly settling coaggregates within 15 min"
A. naeslundii and S. sanguinis Planktonic Coaggregation
A. naeslundii AK6 and S. sanguinis SK150 formed small suspended aggregates within 2 h in the separate planktonic assay, weaker than the A. naeslundii-S. mitis association. The source/target fields identify the measured pair, not a direction of facilitation. This does not establish an attachment route or acidification mechanism in the five-species flow biofilm.
Source Taxon: Actinomyces naeslundii
Target Taxon: Streptococcus sanguinis
Evidence
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PMID:21966490 - SUPPORT (IN_VITRO)"When A. naeslundii AK6 was mixed with S. sanguinis SK150, small uniform aggregates that remained in suspension formed within 2 h"
Five-species glucose acidification of the biofilm interface
Sequentially assembled five-species plastic flow-channel biofilms showed extracellular acidification after 0.4% or 10% glucose in sterile saliva, while the no-glucose control remained above pH 7. Spatial pH differences persisted for hours. This is a collective glucose-response endpoint, not demonstrated niche partitioning, metabolite exchange, species-specific acid flux or enamel demineralization. Growth in flowing diluted Todd-Hewitt broth and the later salivary glucose challenge are distinct stages.
Participating Taxa: Streptococcus oralis, Streptococcus sanguinis, Streptococcus mitis, Streptococcus downei, Actinomyces naeslundii
Metabolites: glucose (CHEBI:17234 · MediaIngredientMech · CMMMech)
Biological Processes:
- glycolytic process (GO:0006096 · PathwayMech)
Evidence
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PMID:21966490 - SUPPORT (IN_VITRO)"Anaerobic glycolysis in the model biofilms created a mildly acidic environment. Decrease in pH in different areas of the biofilms varied, and distinct extracellular pH-microenvironments were conserved over several hours."
Knowledge gaps & discussions (1)
KNOWLEDGE_GAP OPEN Does either pairwise coaggregation mechanism mediate biofilm acidification?
Planktonic coaggregation and glucose-responsive biofilm pH were measured in different assays. Neither pair was selectively disrupted or rescued in the biofilm; physical association does not establish colonization benefit or mediation of the pH response. Resolve species-specific acid flux and the origin of persistent pH heterogeneity experimentally. The two workflow-to-outcome arrows are removed. Flow rate, growth feed, substrate and temperature-stage metadata remain under #1420.
Attaches to: ecological_interactions#A. naeslundii and S. mitis Planktonic Coaggregation, ecological_interactions#A. naeslundii and S. sanguinis Planktonic Coaggregation, ecological_interactions#Five-species glucose acidification of the biofilm interface
Environmental Factors
| Factor | Value | Unit |
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| Glucose challenge | N/A | |
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| Persistent acidic microenvironments | N/A | |
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Growth Media
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