identifier: METPO:1000487 label: temperature delta high definition: A temperature delta phenotype with a growth-supporting temperature breadth above approximately 30 °C, characteristic of extreme-eurythermal physiology. 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_>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 very broad homoviscous remodeling capacity as the basis of extreme-eurythermal physiology. - reference: DOI:10.1128/MMBR.65.1.1-43.2001 snippet: resistant to irreversible inactivation at high temperatures notes: Thermostable-protein review supports robust thermostability as the basis of extending tolerance beyond standard mesophile ranges. causal_graphs: - graph_id: temperature_delta_high_eurythermal title: Temperature-delta-high eurythermal breadth description: DOI-backed graph linking maximal thermal-adaptation flexibility to a temperature growth breadth above 30 °C. nodes: - node_id: temperature_delta_high_trait label: temperature delta high node_type: TRAIT grounding: METPO:1000487 description: Temperature growth-supporting breadth above ~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: maximal_thermal_adaptation label: maximal thermal-adaptation flexibility node_type: BIOLOGICAL_PROCESS description: Combined membrane remodeling and protein-thermostability capacity supporting growth across an extreme temperature span. - node_id: decreased_growth_temperature label: decreased growth temperature node_type: ENVIRONMENTAL_FACTOR description: A decrease in ambient growth temperature. - node_id: unsaturated_fatty_acid_biosynthesis label: unsaturated fatty acid biosynthesis node_type: BIOLOGICAL_PROCESS description: Biosynthesis of unsaturated fatty acids for membrane remodeling. grounding: GO:0006636 - node_id: homoviscous_adaptation label: homoviscous adaptation node_type: BIOLOGICAL_PROCESS description: Temperature-driven remodeling of membrane lipid composition to maintain bilayer order. - node_id: membrane_fluidity_homeostasis label: membrane fluidity homeostasis node_type: STATE description: Maintenance of membrane fluidity and permeability across thermal shifts. - node_id: decreased_membrane_fluidity label: decreased membrane fluidity node_type: STATE description: Reduced membrane fluidity sensed as a signal upon cooling. - node_id: lipid_desaturase_activity label: lipid desaturase activity node_type: MOLECULAR_FUNCTION description: Desaturase activity introducing cis double bonds into fatty acids. - node_id: membrane_fluidity label: membrane fluidity node_type: QUALITY description: Physical fluidity of the membrane lipid bilayer. grounding: METPO:1007505 - node_id: cis_trans_isomerase_activity label: cis-trans isomerase activity node_type: MOLECULAR_FUNCTION description: Isomerization of existing unsaturated fatty acids to trans configuration. grounding: GO:0016859 - node_id: membrane_viscosity_high_temperature label: membrane viscosity at higher temperature node_type: QUALITY description: Increased membrane viscosity to counter excess fluidity during warming. - node_id: increased_fatty_acid_diversity label: increased short-/branched-/unsaturated fatty acids node_type: CHEMICAL description: Shifts toward short-chain, branched-chain and unsaturated fatty acids in the membrane. - node_id: thermostable_enzyme label: hyperthermophilic enzyme thermostability node_type: QUALITY description: Intrinsic thermostability of enzymes from hyperthermophiles. - node_id: irreversible_protein_inactivation label: irreversible inactivation at high temperatures node_type: BIOLOGICAL_PROCESS description: Irreversible loss of protein activity at high temperatures. edges: - subject: maximal_thermal_adaptation predicate: produces object: temperature_delta_high_trait description: Maximal thermal-adaptation flexibility yields an extreme temperature-delta breadth. evidence: - reference: DOI:10.1128/MMBR.65.1.1-43.2001 snippet: resistant to irreversible inactivation at high temperatures notes: Supports maximal thermal-adaptation as the basis of extreme eurythermal breadth. predicate_id: METPO:2000202 - subject: temperature_delta_high_trait predicate: is a object: temperature_delta description: Temperature delta high is a quantitative bin of the temperature-delta phenotype. evidence: - reference: DOI:10.1146/annurev-micro-091313-103612 snippet: more unsaturated fatty acids notes: Supports the >30 °C breadth as a value within the temperature-delta distribution. predicate_id: rdfs:subClassOf - subject: decreased_growth_temperature predicate: increases object: unsaturated_fatty_acid_biosynthesis description: Lower growth temperature increases incorporation of unsaturated fatty acids (homoviscous adaptation). evidence: - reference: DOI:10.1146/annurev-micro-091313-103612 notes: Bacteria remodel membrane fluidity via proportionally more unsaturated fatty acids as growth temperature decreases. predicate_id: RO:0002213 - subject: homoviscous_adaptation predicate: maintains object: membrane_fluidity_homeostasis description: Homoviscous adaptation maintains membrane fluidity/permeability homeostasis across thermal shifts. evidence: - reference: DOI:10.1146/annurev-micro-091313-103612 notes: Homoviscous adaptation disrupts lipid bilayer order and optimizes cellular processes at the new temperature. - subject: decreased_membrane_fluidity predicate: upregulates object: unsaturated_fatty_acid_biosynthesis description: Reduced membrane fluidity is sensed and upregulates unsaturated fatty acid biosynthesis. evidence: - reference: DOI:10.1146/annurev-micro-091313-103612 notes: Microbes sense decreased membrane fluidity and initiate responses that upregulate unsaturated fatty acid biosynthesis. - subject: lipid_desaturase_activity predicate: increases object: membrane_fluidity description: Lipid desaturases introduce cis double bonds (~30 deg kink) creating packing defects that increase fluidity. evidence: - reference: DOI:10.3390/cells12101353 notes: Organisms maintain membrane fluidity by activating lipid desaturases that introduce cis double bonds to increase packing defects and fluidity. predicate_id: RO:0002213 - subject: cis_trans_isomerase_activity predicate: increases object: membrane_viscosity_high_temperature description: Cis-trans isomerization of existing UFAs yields trans-UFAs resembling SFAs, raising membrane viscosity during warming. evidence: - reference: DOI:10.3390/cells12101353 notes: Cis-trans isomerase converts UFAs; trans-UFAs resemble SFAs and raise membrane viscosity, compensating at higher temperature. predicate_id: RO:0002213 - subject: increased_fatty_acid_diversity predicate: increases object: membrane_fluidity description: Shifts in acyl chain length/branching and unsaturation jointly increase membrane fluidity at lower temperatures. evidence: - reference: DOI:10.3390/cells12101353 notes: Membrane composition adjustments (SCFA, BCFA, unsaturation, lysophospholipids) can increase membrane fluidity at lower temperatures. predicate_id: RO:0002213 - subject: thermostable_enzyme predicate: resists object: irreversible_protein_inactivation description: Intrinsic enzyme thermostability resists irreversible inactivation, extending upper growth limits. evidence: - reference: DOI:10.1128/MMBR.65.1.1-43.2001 notes: Enzymes from hyperthermophiles are typically thermostable, i.e., resistant to irreversible inactivation at high temperatures. curation_history: - timestamp: '2026-05-05T01:35:46.845441+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 maximal thermal-adaptation flexibility to the eurythermal temperature-delta-high 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 7 evidence-backed generic edges (12 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:0002213×4). llm_assisted: true - timestamp: '2026-06-24T17:21:17Z' curator: claude action: GROUND_CAUSAL_NODES changes: Grounded 1 causal-node grounding field(s) via mappings/node_grounding.tsv (METPO:1007505×1). llm_assisted: true - timestamp: '2026-06-24T17:23:31Z' curator: claude action: GROUND_CAUSAL_NODES changes: Grounded 2 causal-node grounding field(s) via mappings/node_grounding.tsv (GO:0006636×1, GO:0016859×1). llm_assisted: true