A defined four-member consortium of metabolically distinct human gut anaerobes — Eubacterium hallii, Roseburia intestinalis, Marvinbryantia formatexigens and Faecalibacterium prausnitzii — assembled in all pairwise combinations and as the full community, on distinct carbon sources, and profiled by species-resolved proteomics. The finding is regulatory rather than compositional: bacteria modulate protein abundance in response to specific partners, and those partner-specific shifts reduce functional overlap between members and are frequently associated with increased community productivity. Biotic interactions, not the carbon source, dominated proteomic variation. The record captures a community whose members divide labour by changing what they express in each other's presence, so metabolic complementarity is an outcome of regulation rather than a fixed property of the members.
Taxonomy
| Taxon | Ontology ID | Functional Roles | Abundance |
|---|---|---|---|
| Eubacterium hallii — ontology label: Anaerobutyricum hallii | NCBITaxon:39488 · TaxonMech · TraitMech | N/A | |
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| Roseburia intestinalis | NCBITaxon:166486 · TaxonMech · TraitMech | N/A | |
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| Marvinbryantia formatexigens | NCBITaxon:168384 · TaxonMech · TraitMech | N/A | |
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| Faecalibacterium prausnitzii | NCBITaxon:853 · 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.
Partner-Specific Proteome Remodelling
Co-cultured gut strains showed partner-associated protein-expression changes. Abundance-matched mixed-isolate protein controls help separate expression changes from composition and detection effects. Both community context and carbon source affected proteomes; partner effects were not absence of carbon effects. The four canonical participants define the human consortium, not a claim that every strain met protein-detection thresholds in every condition. Pooled human/rumen analyses must not be assigned wholesale to the human four-member condition.
Participating Taxa: Eubacterium hallii, Roseburia intestinalis, Marvinbryantia formatexigens, Faecalibacterium prausnitzii
Biological Processes:
- regulation of gene expression (GO:0010468 · PathwayMech)
PARTIAL - partner-dependent expression changes can change which annotated functions overlap among detected community members. Co-culture and matched mixed-isolate comparisons support a proteomic response, but do not selectively identify the regulatory pathway or establish competitive niche partitioning and metabolite flux.
Evidence
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PMID:42032280 - SUPPORT (IN_VITRO)"These interactions led to reproducible, partner-specific expression shifts that significantly reduced functional overlap and were frequently associated with increased community productivity"
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PMID:42032280 - SUPPORT (IN_VITRO)"We found that biotic interactions, rather than abiotic conditions, were the dominant drivers of proteomic variation"
Reduced Annotated Proteomic Functional Overlap
Protein-to-KEGG annotation and presence/absence comparisons showed reduced expressed functional overlap in many tested communities relative to corresponding monoculture expectations. This positive proteomic metric does not directly measure competition, coexistence, substrate partitioning or metabolite transfer. Butyrate, formate and acetate are contextual member capabilities, not quantified exchanged products in this analysis. Study-wide frequencies pooled human and rumen communities and do not establish the same result for every human strain combination or carbon condition.
Participating Taxa: Eubacterium hallii, Roseburia intestinalis, Marvinbryantia formatexigens, Faecalibacterium prausnitzii
Metabolites: butyrate (CHEBI:17968 · MediaIngredientMech · CMMMech), formate (CHEBI:15740 · MediaIngredientMech · CMMMech), acetate (CHEBI:30089 · MediaIngredientMech · CMMMech)
PARTIAL - reduced redundant expression could spare resources and contribute to greater community productivity. The observed association supports this proposed explanation, but regulatory or energetic-cost perturbations did not selectively establish that reduced annotated overlap mediates the qPCR yield difference.
Evidence
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PMID:42032280 - SUPPORT (IN_VITRO)"These interactions led to reproducible, partner-specific expression shifts that significantly reduced functional overlap and were frequently associated with increased community productivity"
Community qPCR Productivity Association
Lower annotated functional overlap was associated with higher community productivity across the analyzed communities. Methods define productivity using total consortium qPCR abundance divided by mean monoculture abundance, not the sum or best monoculture. qPCR gene-copy abundance is not direct viable-cell biomass, and greater community yield does not demonstrate reciprocal benefit to every member. The pooled association was not a simple linear dose-response and does not establish that reduced overlap caused productivity.
Participating Taxa: Eubacterium hallii, Roseburia intestinalis, Marvinbryantia formatexigens, Faecalibacterium prausnitzii
Metabolites: butyrate (CHEBI:17968 · MediaIngredientMech · CMMMech)
Evidence
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PMID:42032280 - SUPPORT (IN_VITRO)"These interactions led to reproducible, partner-specific expression shifts that significantly reduced functional overlap and were frequently associated with increased community productivity"
Knowledge gaps & discussions (1)
KNOWLEDGE_GAP OPEN Does altered proteome overlap cause higher community productivity?
The positive controlled proteomic responses and overlap metric are distinct from proposed niche partitioning and resource savings. Competition and coexistence were not directly measured. Protein coverage thresholds and abundance-matched mixed-isolate controls matter; all four canonical human taxa are not guaranteed detectable in every comparison. Preserve carbon effects, separate pooled human/rumen statistics from exact human conditions, and use the Methods mean-monoculture denominator. Pathway or regulatory perturbations, resource budgets and flux measurements would test the two retained PARTIAL arrows; no organism-level mutualism or specific butyrate/formate/acetate exchange is demonstrated. Non-graph strain, medium and capability metadata is preserved, not recertified.
Attaches to: ecological_interactions#Partner-Specific Proteome Remodelling, ecological_interactions#Reduced Annotated Proteomic Functional Overlap, ecological_interactions#Community qPCR Productivity Association
Environmental Factors
| Factor | Value | Unit |
|---|---|---|
| Distinct carbon sources | N/A | |
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Growth Media
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