identifier: traitmech:000066 label: intracellular inclusion definition: A morphology trait describing a discrete intracellular body — a storage granule, gas-filled structure, or protein-bounded microcompartment/organelle — that compartmentalizes material or function within a prokaryotic cell. definition_source: DOI:10.1038/s41579-020-0413-0 trait_category: MORPHOLOGY term_kind: CLASS mapping_status: REVIEWED parent_traits: - METPO:1000059 synonyms: - synonym_text: cytoplasmic inclusion synonym_type: RELATED_SYNONYM source: DOI:10.1038/s41579-020-0413-0 evidence: - reference: DOI:10.1038/s41579-020-0413-0 notes: Greening & Lithgow, "Formation and function of bacterial organelles", establish that bacteria contain diverse inclusions/organelles (storage granules, gas vesicles, microcompartments, magnetosomes); parent of the inclusion sub-variants. - reference: DOI:10.1038/nrmicro.2018.10 notes: Kerfeld et al. review bacterial microcompartments as a major class of protein-bounded intracellular organelles. causal_graphs: - graph_id: inclusion_compartmentalization title: Intracellular inclusions compartmentalize prokaryotic cytoplasm description: Evidence-backed causal sketch linking discrete intracellular inclusions (storage granules, gas vesicles, microcompartments) to cytoplasmic compartmentalization. nodes: - node_id: inclusion_trait label: intracellular inclusion node_type: TRAIT grounding: traitmech:000066 description: Discrete intracellular body compartmentalizing material or function. - node_id: cytoplasmic_compartmentalization label: cytoplasmic compartmentalization node_type: QUALITY description: Spatial segregation of material or activity within the cytoplasm. - node_id: bacterial_microcompartment label: bacterial microcompartment node_type: CELLULAR_LOCALIZATION grounding: GO:0031469 description: Protein-shelled prokaryotic organelle (e.g. carboxysome). - node_id: pha_synthase_pathway label: PhaA/PhaB/PhaC pathway node_type: PATHWAY description: Beta-ketothiolase/reductase/PHA synthase pathway producing polyhydroxyalkanoate. - node_id: pha_granule label: PHA granule node_type: CELLULAR_LOCALIZATION description: Polyhydroxyalkanoate storage inclusion body. grounding: GO:0070088 - node_id: nitrogen_depletion label: nitrogen depletion node_type: ENVIRONMENTAL_FACTOR description: Nutrient limitation (low N) triggering carbon storage accumulation. - node_id: polyphosphate_kinase label: polyphosphate kinase (Ppk) node_type: GENE_OR_PROTEIN description: Enzyme catalyzing polyphosphate synthesis. - node_id: polyphosphate_granule label: polyphosphate granule node_type: CELLULAR_LOCALIZATION description: Inorganic polyphosphate (volutin) storage inclusion. - node_id: gas_vesicle_gene_cluster label: gas vesicle gene cluster node_type: GENE_OR_PROTEIN description: gvp operon encoding gas vesicle structural and assembly proteins. - node_id: gas_vesicle label: gas vesicle node_type: ORGANELLE description: Hollow gas-filled protein nanocompartment. grounding: GO:0031411 - node_id: buoyancy label: buoyancy node_type: CAPACITY description: Capacity for vertical positioning in the water column. - node_id: bmc_metabolic_cargo label: encapsulated metabolic enzymes node_type: GENE_OR_PROTEIN description: Enzymes/pathway segment sequestered within a microcompartment shell. - node_id: sulfide_oxidation label: sulfide oxidation node_type: BIOLOGICAL_PROCESS description: Oxidation of sulfide via elemental sulfur intermediate. grounding: GO:0019418 - node_id: sulfur_globule label: intracellular sulfur globule node_type: CELLULAR_LOCALIZATION description: Intracellular elemental sulfur (S0) storage inclusion. edges: - subject: inclusion_trait predicate: enables object: cytoplasmic_compartmentalization description: Inclusions partition activities within the prokaryotic cytoplasm. evidence: - reference: DOI:10.1038/s41579-020-0413-0 notes: Greening & Lithgow review formation and function of bacterial organelles/inclusions. predicate_id: RO:0002327 - subject: bacterial_microcompartment predicate: example of object: inclusion_trait description: Bacterial microcompartments are protein-bounded inclusion organelles. evidence: - reference: DOI:10.1038/nrmicro.2018.10 notes: Kerfeld et al. review bacterial microcompartments as protein-bounded intracellular organelles. predicate_id: rdfs:subClassOf - subject: pha_synthase_pathway predicate: produces object: pha_granule description: The Pha biosynthetic pathway synthesizes PHA chains that form storage granules. evidence: - reference: DOI:10.3390/molecules29102293 notes: '"Synthesized PHA chains form intracellular inclusion bodies commonly called PHA granules"; storage-granule subclass.' predicate_id: METPO:2000202 - subject: nitrogen_depletion predicate: increases accumulation of object: pha_granule description: Depletion of N (and S, P) is a broad trigger for PHA granule accumulation. evidence: - reference: DOI:10.3390/molecules29102293 notes: '"Environmental and cultivation triggers for accumulation include... depletion of N, S, P"; broad, not species-specific.' - subject: polyphosphate_kinase predicate: synthesizes object: polyphosphate_granule description: Ppk catalyzes polyphosphate synthesis forming the polyP/volutin granule. evidence: - reference: DOI:10.3390/foods14132211 notes: '"polyP synthesis is catalyzed by polyphosphate kinase (Ppk)".' - subject: gas_vesicle_gene_cluster predicate: encodes object: gas_vesicle description: The gvp gene cluster encodes the gas vesicle organelle. evidence: - reference: DOI:10.1186/s13036-024-00426-3 notes: '"gene-encoded, inert, hollow, gas-filled protein nanoparticles"; direct definitional edge.' predicate_id: biolink:encodes - subject: gas_vesicle predicate: enables object: buoyancy description: Gas vesicles confer buoyancy enabling positioning in the water column. evidence: - reference: DOI:10.1186/s13036-024-00426-3 notes: '"enabling buoyancy for microbes"; core phenotype/function edge.' predicate_id: RO:0002327 - subject: bacterial_microcompartment predicate: encapsulates object: bmc_metabolic_cargo description: BMC shells encapsulate a segment of a metabolic pathway in a selectively permeable shell. evidence: - reference: DOI:10.1042/bst20230229 notes: '"encapsulate a segment of a metabolic pathway within a selectively permeable protein shell"; direct BMC definition.' - subject: sulfide_oxidation predicate: forms object: sulfur_globule description: Sulfide oxidation proceeds via intracellular accumulation of elemental sulfur globules. evidence: - reference: DOI:10.1371/journal.pone.0310265 notes: '"oxidized to sulfate through an intermediate accumulation of elemental sulfur (S0) within the cell in the form of sulfur globules"; definitional.' predicate_id: biolink:produces curation_history: - timestamp: '2026-06-03T00:00:00Z' curator: claude action: PROPOSED_FROM_RESEARCH changes: Proposed candidate MORPHOLOGY axis class (intracellular inclusion) to parent the storage-granule, gas-vesicle, magnetosome, and carboxysome traits. llm_assisted: true - timestamp: '2026-06-09T15:00:00Z' curator: claude action: CURATED_CAUSAL_GRAPH changes: Added evidence-backed causal graph (compartmentalization axis) with GO node grounding and RO/RDFS 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 (11 new nodes) from the deep-research report. llm_assisted: true - timestamp: '2026-06-24T17:21:13Z' curator: claude action: GROUND_CAUSAL_PREDICATES changes: Grounded 4 causal-edge predicate_id field(s) via mappings/predicate_grounding.tsv (METPO:2000202×1, biolink:encodes×1, RO:0002327×1, biolink:produces×1). llm_assisted: true - timestamp: '2026-06-24T17:23:33Z' curator: claude action: GROUND_CAUSAL_NODES changes: Grounded 3 causal-node grounding field(s) via mappings/node_grounding.tsv (GO:0070088×1, GO:0031411×1, GO:0019418×1). llm_assisted: true