identifier: METPO:1000442 label: temperature optimum low definition: A temperature optimum phenotype with the best-growth ambient temperature between approximately 10 and 22 °C, characteristic of psychrophilic or psychrotolerant physiology. definition_source: DOI:10.1038/sj.embor.7400662 trait_category: ENVIRONMENT term_kind: CLASS mapping_status: REVIEWED parent_traits: - METPO:1000304 synonyms: - synonym_text: Psychrophile synonym_type: EXACT_SYNONYM source: metpo.owl - synonym_text: Psychrotolerant synonym_type: EXACT_SYNONYM source: metpo.owl - synonym_text: TO_10_to_22 synonym_type: RELATED_SYNONYM source: metpo.owl evidence: - reference: DOI:10.1038/sj.embor.7400662 snippet: growing well at temperatures around the freezing point of water notes: Psychrophile review supports low-but-not-freezing optima as the psychrophile / psychrotolerant category. causal_graphs: - graph_id: temperature_optimum_low_psychrotolerant_setpoint title: Temperature-optimum-low psychrotolerant setpoint description: DOI-backed graph linking cold-tolerant membrane and enzyme adaptation to a temperature optimum between 10 and 22 °C. nodes: - node_id: temperature_optimum_low_trait label: temperature optimum low node_type: TRAIT grounding: METPO:1000442 description: Temperature optimum approximately 10–22 °C. - node_id: temperature_optimum label: temperature optimum node_type: TRAIT grounding: METPO:1000304 description: Ambient temperature supporting maximal growth. - node_id: cool_environment label: cool environment node_type: ENVIRONMENTAL_FACTOR description: Habitat ambient temperature in the 10–22 °C range. - node_id: psychrotolerant_adaptation label: psychrotolerant adaptation node_type: BIOLOGICAL_PROCESS description: Mild cold-adaptation of membrane lipid composition and enzyme flexibility sustaining function at cool temperatures. - node_id: low_temperature label: low temperature node_type: ENVIRONMENTAL_FACTOR description: Cool ambient temperature stress (~0-20 C) experienced by the cell. grounding: PATO:0001306 - node_id: membrane_fluidity label: membrane fluidity node_type: QUALITY description: Physical state of the lipid bilayer enabling proper membrane function. grounding: METPO:1007505 - node_id: membrane_unsaturation label: fatty-acyl unsaturation node_type: QUALITY description: Degree of unsaturation of membrane fatty-acyl chains. - node_id: cold_shock_proteins label: cold shock proteins node_type: GENE_OR_PROTEIN description: CSP family proteins induced during temperature downshifts below 20 C. - node_id: compatible_solutes label: compatible solutes node_type: CHEMICAL description: Osmolytes (e.g. glycine betaine, trehalose, glycerol) accumulated under cold stress. grounding: CHEBI:25728 - node_id: protein_membrane_stabilization label: protein and membrane stabilization node_type: BIOLOGICAL_PROCESS description: Stabilization of proteins and membranes and freezing-point depression by cryoprotectants. - node_id: ice_binding_proteins label: ice-binding/antifreeze proteins node_type: GENE_OR_PROTEIN description: IBPs/AFPs that bind ice crystal surfaces and inhibit ice recrystallization. - node_id: ice_crystal_growth label: ice crystal growth node_type: BIOLOGICAL_PROCESS description: Growth and recrystallization of intracellular/extracellular ice crystals. - node_id: oxidative_stress label: oxidative stress node_type: BIOLOGICAL_PROCESS description: Increased ROS from elevated oxygen solubility at low temperature. - node_id: pufa_biosynthesis label: PUFA biosynthesis node_type: PATHWAY description: Biosynthesis of polyunsaturated fatty acids incorporated into membrane lipids. edges: - subject: cool_environment predicate: engages object: psychrotolerant_adaptation description: Cool environments engage psychrotolerant adaptation programs. evidence: - reference: DOI:10.1038/sj.embor.7400662 snippet: decreased membrane fluidity notes: Supports cool-temperature membrane-stress responses as the basis of cool-range optima. - subject: psychrotolerant_adaptation predicate: produces object: temperature_optimum_low_trait description: Psychrotolerant adaptation yields a 10–22 °C temperature optimum. evidence: - reference: DOI:10.1146/annurev-micro-091313-103612 snippet: more unsaturated fatty acids notes: Supports homoviscous adaptation as the mechanism setting cool-range optima. predicate_id: METPO:2000202 - subject: temperature_optimum_low_trait predicate: is a object: temperature_optimum description: Temperature optimum low is a quantitative bin of the temperature-optimum phenotype. evidence: - reference: DOI:10.1038/sj.embor.7400662 snippet: growing well at temperatures around the freezing point of water notes: Supports a 10–22 °C optimum as a value within the temperature-optimum distribution. predicate_id: rdfs:subClassOf - subject: membrane_unsaturation predicate: increases object: membrane_fluidity description: Increased fatty-acyl unsaturation fluidizes the membrane. evidence: - reference: DOI:10.1128/spectrum.03925-23 notes: fluidizing the membrane and reducing bilayer thickness; broadly generalizable homeoviscous adaptation. predicate_id: RO:0002213 - subject: low_temperature predicate: induces object: cold_shock_proteins description: Low temperature induces cold shock proteins. evidence: - reference: DOI:10.37256/amtt.5220244537 notes: CSPs induced at high levels during temperature shifts below 20 C. - subject: low_temperature predicate: promotes accumulation of object: compatible_solutes description: Low temperature promotes accumulation of compatible solutes. evidence: - reference: DOI:10.37256/amtt.5220244537 notes: 'Compatible solutes listed: glycine, betaine, glycerol, trehalose, sucrose, mannitol, sorbitol.' - subject: compatible_solutes predicate: stabilizes object: protein_membrane_stabilization description: Compatible solutes stabilize proteins and membranes and depress freezing point. evidence: - reference: DOI:10.37256/amtt.5220244537 notes: with functions in freezing-point depression and stabilization. - subject: ice_binding_proteins predicate: inhibits object: ice_crystal_growth description: Ice-binding/antifreeze proteins bind ice surfaces and inhibit ice growth/recrystallization. evidence: - reference: DOI:10.37256/amtt.5220244537 notes: AFGPs play crucial roles in protecting cells by binding to ice crystal surfaces. predicate_id: RO:0002212 - subject: low_temperature predicate: increases object: oxidative_stress description: Low temperature increases oxygen solubility and ROS/oxidative stress. evidence: - reference: DOI:10.37256/amtt.5220244537 notes: Cold causes increased oxygen solubility and ROS. predicate_id: RO:0002213 - subject: pufa_biosynthesis predicate: maintains object: membrane_fluidity description: PUFA biosynthesis maintains membrane fluidity at low temperature. evidence: - reference: DOI:10.3390/genes14010158 notes: maintain membrane fluidity; broadly generalizable mechanism. curation_history: - timestamp: '2026-05-05T01:35:46.819249+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 psychrotolerant adaptation to the temperature-optimum-low 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 (10 new nodes) from the deep-research report. llm_assisted: true - timestamp: '2026-06-24T17:21:11Z' curator: claude action: GROUND_CAUSAL_PREDICATES changes: Grounded 3 causal-edge predicate_id field(s) via mappings/predicate_grounding.tsv (RO:0002213×2, RO:0002212×1). llm_assisted: true - timestamp: '2026-06-24T17:21:17Z' curator: claude action: GROUND_CAUSAL_NODES changes: Grounded 3 causal-node grounding field(s) via mappings/node_grounding.tsv (PATO:0001306×1, METPO:1007505×1, CHEBI:25728×1). llm_assisted: true