identifier: traitmech:000052 label: gut-associated definition: A host association in which an organism is a persistent member of the gastrointestinal microbiota of an animal host, often contributing to host nutrition and physiology. definition_source: DOI:10.1126/science.1104816 trait_category: ECOLOGY term_kind: CLASS mapping_status: REVIEWED parent_traits: - traitmech:000049 synonyms: - synonym_text: intestinal synonym_type: RELATED_SYNONYM source: DOI:10.1126/science.1104816 evidence: - reference: DOI:10.1126/science.1104816 notes: Bäckhed et al. characterize the distal intestine as a dense microbial habitat whose residents provide metabolic capabilities to the host. - reference: DOI:10.1073/pnas.1218525110 notes: McFall-Ngai et al. support the gut as a major site of host-associated microbial communities across animals. canonical_examples: - taxon_id: NCBITaxon:818 taxon_label: Bacteroides thetaiotaomicron note: "Canonical human-gut-symbiont model (polysaccharide utilisation loci)." reference: PMID:12663928 causal_graphs: - graph_id: gut_associated_microbiota_metabolism title: Gut-associated lifestyle in the gastrointestinal microbiota description: Evidence-backed causal sketch linking gastrointestinal habitat to persistent gut-microbiota membership and host nutritional contributions. nodes: - node_id: gut_associated_trait label: gut-associated node_type: TRAIT grounding: traitmech:000052 description: Persistent member of an animal gastrointestinal microbiota. - node_id: gastrointestinal_habitat label: gastrointestinal tract habitat node_type: ENVIRONMENTAL_FACTOR description: Animal distal intestine and other GI compartments. - node_id: host_metabolic_contribution label: host metabolic contribution node_type: BIOLOGICAL_PROCESS description: Microbially mediated nutrient harvest and metabolism for the host. - node_id: adhesins label: bacterial adhesins node_type: GENE_OR_PROTEIN description: Bacterial surface adhesins that bind host receptors. - node_id: mucosal_adhesion label: adhesion to intestinal mucus/epithelium node_type: BIOLOGICAL_PROCESS description: Binding of bacterial adhesins to intestinal mucus or epithelial receptors. - node_id: bile_acids label: bile acids/bile salts node_type: CHEMICAL description: Host bile acids and conjugated bile salts in the gut. - node_id: antimicrobial_peptides label: Paneth-cell antimicrobial peptides node_type: CHEMICAL description: Antimicrobial peptides secreted by Paneth cells in the small intestine. - node_id: small_intestinal_bacterial_growth label: bacterial growth in small intestine node_type: BIOLOGICAL_PROCESS description: Growth of bacteria in the small-intestinal lumen. - node_id: peristalsis label: intestinal peristalsis node_type: ENVIRONMENTAL_FACTOR description: Mechanical flow/clearance of luminal contents in the gut. - node_id: duodenal_retention label: colonization/retention in duodenum node_type: BIOLOGICAL_PROCESS description: Persistent retention/colonization in the duodenum and proximal small intestine. - node_id: luminal_oxygen_limitation label: limitation of colonic luminal oxygen diffusion node_type: BIOLOGICAL_PROCESS description: Host functions that limit oxygen diffusion into the colonic lumen during homeostasis. - node_id: primary_fermenter_community label: primary-fermenter-dominated community node_type: STATE description: A gut microbial community dominated by anaerobic primary fermenters. edges: - subject: gastrointestinal_habitat predicate: enables object: gut_associated_trait description: The intestinal environment supports persistent residency. evidence: - reference: DOI:10.1126/science.1104816 notes: Bäckhed et al. characterize the distal intestine as a dense microbial habitat. predicate_id: RO:0002327 - subject: gut_associated_trait predicate: contributes to object: host_metabolic_contribution description: Gut microbiota provide metabolic capabilities to the host. evidence: - reference: DOI:10.1073/pnas.1218525110 notes: McFall-Ngai et al. support the gut microbiota as a metabolically consequential host-associated community. predicate_id: RO:0002326 - subject: adhesins predicate: enables object: mucosal_adhesion description: Bacterial adhesins bind host receptors to enable adhesion. evidence: - reference: DOI:10.3390/microorganisms12051026 notes: Adhesion primarily relies on adhesins; binding of bacterial adhesins to host receptors is a prerequisite for long-term colonization (Lin et al., 2024). predicate_id: RO:0002327 - subject: mucosal_adhesion predicate: prerequisite for object: gut_associated_trait description: Adhesion to mucus/epithelium is a prerequisite for long-term gut colonization. evidence: - reference: DOI:10.3390/microorganisms12051026 notes: Adhesion emphasized as the prerequisite for persistence (adhesion -> growth -> reproduction) (Lin et al., 2024). - subject: bile_acids predicate: exerts antimicrobial pressure on object: gastrointestinal_habitat description: Bile acids shape gut community via antimicrobial and detergent-like properties. evidence: - reference: DOI:10.1128/spectrum.03576-23 notes: Bile acids shape the gut microbiome composition due to antimicrobial and detergent-like properties, creating a harsh gut environment (McMillan et al., 2024). - subject: bile_acids predicate: inhibits object: small_intestinal_bacterial_growth description: Small-intestinal bile salts inhibit growth of many bacteria. evidence: - reference: DOI:10.1016/j.chom.2024.05.011 notes: Bile salts and Paneth-cell antimicrobial peptides inhibit growth of many bacteria in the small intestine (Muramatsu & Winter, 2024). predicate_id: RO:0002212 - subject: antimicrobial_peptides predicate: inhibits object: small_intestinal_bacterial_growth description: Paneth-cell antimicrobial peptides inhibit growth of many small-intestinal bacteria. evidence: - reference: DOI:10.1016/j.chom.2024.05.011 notes: Antimicrobial peptides released by Paneth cells inhibit growth of many bacteria in the small intestine (Muramatsu & Winter, 2024). predicate_id: RO:0002212 - subject: peristalsis predicate: reduces object: duodenal_retention description: Strong peristalsis (plus bile/antimicrobials) makes the duodenum hostile to retention. evidence: - reference: DOI:10.3390/microorganisms12051026 notes: The duodenum is hostile to retention due to bile, antimicrobials, and strong peristalsis (Lin et al., 2024). predicate_id: METPO:2000017 - subject: luminal_oxygen_limitation predicate: enables object: primary_fermenter_community description: Host limitation of luminal oxygen shelters a primary-fermenter-dominated community. evidence: - reference: DOI:10.1128/iai.00302-24 notes: During homeostasis, host functions that limit oxygen diffusion into the colonic lumen shelter a community dominated by primary fermenters (Lee et al., 2024). predicate_id: RO:0002327 curation_history: - timestamp: '2026-06-02T00:00:00Z' curator: claude action: PROPOSED_FROM_RESEARCH changes: Proposed candidate ECOLOGY trait (gut-associated); sub-variant of host-associated. llm_assisted: true - timestamp: '2026-06-09T14:00:00Z' curator: claude action: CURATED_CAUSAL_GRAPH changes: Added evidence-backed causal graph (gut microbiota / host metabolic contribution) with RO predicate groundings; promoted PROPOSED to REVIEWED. llm_assisted: true - timestamp: '2026-06-23T00:00:00Z' curator: claude action: ENRICH_CAUSAL_GRAPH changes: Added 7 evidence-backed generic edges (9 new nodes) from the deep-research report. llm_assisted: true - timestamp: '2026-06-24T17:21:09Z' curator: claude action: GROUND_CAUSAL_PREDICATES changes: Grounded 5 causal-edge predicate_id field(s) via mappings/predicate_grounding.tsv (RO:0002327×2, RO:0002212×2, METPO:2000017×1). llm_assisted: true discussions: - discussion_id: kgscan-4fc1a06fa1e3 prompt: 'Knowledge gap for gut-associated: MicroRNAs (miRNAs) are small, noncoding RNAs involved in posttranscriptional gene regulation in both animal and plant. miRNAs derived from edible plants, referred to as xenomiRs, are proposed to cross-kingdom barriers and to modulate mammalian gene expression.' kind: KNOWLEDGE_GAP status: OPEN rationale: 'Surfaced by the Europe PMC literature gap-signal scan (categories: controversy_conflict, explicit_gap, future_work, limitations_barriers, unclear_unknown). Curator review required: set attaches_to, refine the prompt, and weigh the cited evidence.' attaches_to: [] evidence: - reference: PMID:40945860 supports: NO_EVIDENCE evidence_source: abstract snippet: MicroRNAs (miRNAs) are small, noncoding RNAs involved in posttranscriptional gene regulation in both animal and plant. miRNAs derived from edible plants, referred to as xenomiRs, are proposed to cross-kingdom barriers and to modulate mammalian gene expression. explanation: Gap-signal sentence (limitations_barriers) from the cited abstract. - reference: PMID:42278360 supports: NO_EVIDENCE evidence_source: abstract snippet: By integrating microbiological, immunological, and clinical perspectives, this review highlights key knowledge gaps and outlines future research directions aimed at harnessing the gut microbiome as a novel therapeutic avenue in HIV management and eradication. explanation: Gap-signal sentence (explicit_gap, future_work) from the cited abstract. - reference: PMID:41808832 supports: NO_EVIDENCE evidence_source: abstract snippet: Given its promising anti-inflammatory properties, further research is warranted. explanation: Gap-signal sentence (future_work) from the cited abstract. - reference: PMID:42197356 supports: NO_EVIDENCE evidence_source: abstract snippet: Examining the existing literature may identify knowledge gaps regarding precise mechanisms through which the development of GM influences the maturation of the immune system. explanation: Gap-signal sentence (explicit_gap) from the cited abstract. posed_by: kg-microbe-kgscan