identifier: METPO:1000486 label: temperature delta mid2 definition: A temperature delta phenotype with a growth-supporting temperature breadth of approximately 20–30 °C, characteristic of organisms with broad thermal-tolerance breadth. definition_source: DOI:10.1146/annurev-micro-091313-103612 trait_category: ENVIRONMENT term_kind: CLASS mapping_status: REVIEWED parent_traits: - METPO:1000303 synonyms: - synonym_text: Td_20_30 synonym_type: RELATED_SYNONYM source: metpo.owl evidence: - reference: DOI:10.1146/annurev-micro-091313-103612 snippet: more unsaturated fatty acids notes: Membrane-adaptation review supports broad homoviscous remodeling capacity as the basis of eurythermal physiology. causal_graphs: - graph_id: temperature_delta_mid2_broad_breadth title: Temperature-delta-mid2 broad-breadth thermal adaptation description: DOI-backed graph linking broad thermal-adaptation flexibility to a 20–30 °C temperature growth breadth. nodes: - node_id: temperature_delta_mid2_trait label: temperature delta mid2 node_type: TRAIT grounding: METPO:1000486 description: Temperature growth-supporting breadth approximately 20–30 °C. - node_id: temperature_delta label: temperature delta node_type: TRAIT grounding: METPO:1000303 description: Breadth of the growth-supporting ambient-temperature range. - node_id: broad_thermal_adaptation label: broad thermal-adaptation flexibility node_type: BIOLOGICAL_PROCESS description: Strong capacity to remodel membrane lipids and enzymes across temperature shifts of ~20–30 °C. - node_id: des_desaturase label: acyl-lipid desaturase (Des) node_type: GENE_OR_PROTEIN description: Membrane desaturase that introduces double bonds into existing acyl chains. - node_id: unsaturated_fatty_acids label: unsaturated fatty acids node_type: CHEMICAL description: Acyl chains bearing double bonds (CHEBI:27208) that fluidize the membrane. grounding: CHEBI:27208 - node_id: membrane_fluidity label: membrane fluidity / homeoviscous adaptation node_type: BIOLOGICAL_PROCESS description: Maintenance of optimal membrane fluidity across temperatures. - node_id: rpos_sigma_factor label: RpoS sigma factor (sigma-S) node_type: GENE_OR_PROTEIN description: General stress-response sigma factor controlling stress regulons. - node_id: otsab_operon label: otsAB trehalose biosynthesis operon node_type: PATHWAY description: otsA/otsB pathway synthesizing trehalose-6-phosphate and trehalose. - node_id: trehalose label: trehalose node_type: CHEMICAL description: Compatible solute (CHEBI:18150) supporting cold/stress tolerance. - node_id: cold_tolerance label: cold / cold-shock tolerance node_type: BIOLOGICAL_PROCESS description: Response to cold supporting growth/survival at low temperatures. edges: - subject: broad_thermal_adaptation predicate: produces object: temperature_delta_mid2_trait description: Broad thermal-adaptation flexibility yields a 20–30 °C temperature-delta breadth. evidence: - reference: DOI:10.1146/annurev-micro-091313-103612 snippet: more unsaturated fatty acids notes: Supports broad remodeling flexibility as the basis of broad breadth. predicate_id: METPO:2000202 - subject: temperature_delta_mid2_trait predicate: is a object: temperature_delta description: Temperature delta mid2 is a quantitative bin of the temperature-delta phenotype. evidence: - reference: DOI:10.1016/s0300-9629(97)00003-0 snippet: adapted to environments of high temperature notes: Supports the 20–30 °C breadth as a value within the temperature-delta distribution. predicate_id: rdfs:subClassOf - subject: des_desaturase predicate: increases abundance of object: unsaturated_fatty_acids description: Desaturase remodels existing lipids, raising unsaturated:saturated fatty acid ratio. evidence: - reference: DOI:10.1128/spectrum.03925-23 notes: A rapid change in the saturated:unsaturated fatty acid ratio by desaturation of existing lipids. - subject: unsaturated_fatty_acids predicate: increases object: membrane_fluidity description: Unsaturation fluidizes the membrane, supporting homeoviscous adaptation. evidence: - reference: DOI:10.1128/spectrum.03925-23 notes: Desaturation fluidizes the membrane; strong general mechanism. predicate_id: RO:0002213 - subject: membrane_fluidity predicate: enables object: broad_thermal_adaptation description: Maintaining membrane fluidity across temperatures underpins broad thermal-adaptation flexibility. evidence: - reference: DOI:10.1128/spectrum.03925-23 notes: Homeoviscous adaptation via fluidity maintenance underlies adaptation across a temperature range. predicate_id: RO:0002327 - subject: rpos_sigma_factor predicate: positively regulates expression of object: otsab_operon description: RpoS controls cold-shock-triggered induction of the otsAB operon. evidence: - reference: DOI:10.1007/s12275-023-00031-x notes: otsAB induction is RpoS-dependent and triggered by osmotic stress, cold shock, or stationary phase. - subject: otsab_operon predicate: produces object: trehalose description: The otsAB pathway synthesizes trehalose. evidence: - reference: DOI:10.1007/s12275-023-00031-x notes: Trehalose is synthesized by the otsAB operon. predicate_id: METPO:2000202 - subject: trehalose predicate: contributes to object: cold_tolerance description: Trehalose acts as a compatible solute supporting cold-shock tolerance. evidence: - reference: DOI:10.1007/s12275-023-00031-x notes: Trehalose helps cold shock tolerance. predicate_id: RO:0002326 curation_history: - timestamp: '2026-05-05T01:35:46.844944+00:00' curator: seed_from_metpo action: SEEDED_FROM_METPO changes: imported from data/raw/metpo.owl (CLASS) llm_assisted: false - timestamp: '2026-05-13T11:00:00-07:00' curator: claude action: CURATED_CAUSAL_GRAPH changes: Added DOI-backed definition and causal graph linking broad thermal-adaptation flexibility to the temperature-delta-mid2 bin. llm_assisted: true - timestamp: '2026-05-20T03:35:30Z' curator: claude action: GROUND_CAUSAL_PREDICATES changes: Grounded 2 causal-edge predicate_id field(s) via mappings/predicate_grounding.tsv (METPO:2000202×1, rdfs:subClassOf×1). llm_assisted: true - timestamp: '2026-06-23T00:00:00Z' curator: claude action: ENRICH_CAUSAL_GRAPH changes: Added 6 evidence-backed generic edges (7 new nodes) from the deep-research report. llm_assisted: true - timestamp: '2026-06-24T17:21:11Z' curator: claude action: GROUND_CAUSAL_PREDICATES changes: Grounded 4 causal-edge predicate_id field(s) via mappings/predicate_grounding.tsv (RO:0002213×1, RO:0002327×1, METPO:2000202×1, RO:0002326×1). llm_assisted: true - timestamp: '2026-06-24T17:23:31Z' curator: claude action: GROUND_CAUSAL_NODES changes: Grounded 1 causal-node grounding field(s) via mappings/node_grounding.tsv (CHEBI:27208×1). llm_assisted: true