identifier: METPO:1000483 label: temperature delta very low definition: A temperature delta phenotype with a growth-supporting temperature breadth of approximately 1–5 °C, characteristic of stenothermal 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_1_5 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 narrow thermal-tolerance breadths as the stenothermal phenotype with limited membrane-remodeling flexibility. causal_graphs: - graph_id: temperature_delta_very_low_stenothermal title: Temperature-delta-very-low stenothermal breadth description: DOI-backed graph linking very limited thermal-adaptation flexibility to a 1–5 °C temperature growth breadth. nodes: - node_id: temperature_delta_very_low_trait label: temperature delta very low node_type: TRAIT grounding: METPO:1000483 description: Temperature growth-supporting breadth approximately 1–5 °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: very_limited_thermal_adaptation label: very limited thermal-adaptation flexibility node_type: BIOLOGICAL_PROCESS description: Narrow capacity to remodel membrane lipid composition and enzyme repertoire across temperature shifts. - node_id: unsaturated_fatty_acid_content label: unsaturated fatty acid content node_type: CHEMICAL description: Proportion of unsaturated fatty acids in membrane phospholipids. - node_id: membrane_fluidity label: membrane fluidity node_type: QUALITY description: Physical fluidity of the cell membrane, central to homeoviscous adaptation. grounding: METPO:1007505 - node_id: cold_shock label: cold shock node_type: ENVIRONMENTAL_FACTOR description: Abrupt decrease in ambient temperature. - node_id: cspa_protein label: CspA cold-shock protein node_type: GENE_OR_PROTEIN description: RNA chaperone induced upon cold shock that promotes single-stranded RNA states. - node_id: csda_helicase label: CsdA DEAD-box RNA helicase node_type: GENE_OR_PROTEIN description: DEAD-box RNA helicase that assists ribosomes and RNA remodeling at low temperature. - node_id: translation_under_cold label: translation under cold shock node_type: BIOLOGICAL_PROCESS description: Maintenance of protein synthesis at low temperature. edges: - subject: very_limited_thermal_adaptation predicate: produces object: temperature_delta_very_low_trait description: Very limited thermal-adaptation flexibility yields a 1–5 °C temperature-delta breadth. evidence: - reference: DOI:10.1146/annurev-micro-091313-103612 snippet: more unsaturated fatty acids notes: Supports very limited remodeling flexibility as the basis of stenothermal breadth. predicate_id: METPO:2000202 - subject: temperature_delta_very_low_trait predicate: is a object: temperature_delta description: Temperature delta very low 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 1–5 °C breadth as a value within the temperature-delta distribution. predicate_id: rdfs:subClassOf - subject: unsaturated_fatty_acid_content predicate: increases object: membrane_fluidity description: Higher unsaturated fatty acid proportion prevents excessive rigidification and maintains membrane fluidity at low temperature. evidence: - reference: DOI:10.1146/annurev-micro-091313-103612 notes: Proportionally more unsaturated fatty acids maintain membrane fluidity within an optimal range; broad across microbes. predicate_id: RO:0002213 - subject: membrane_fluidity predicate: decreased by reduced unsaturated fatty acids object: unsaturated_fatty_acid_content description: Reduced unsaturated fatty acid content decreases membrane fluidity, a direct physical consequence linking composition to cold stress. evidence: - reference: DOI:10.1111/mmi.15323 notes: Decrease in membrane fluidity due to decrease in unsaturated fatty acid content. - subject: cold_shock predicate: induces object: cspa_protein description: Cold shock induces CspA, an RNA chaperone counteracting low-temperature RNA secondary structure. evidence: - reference: DOI:10.1007/s12275-023-00031-x notes: Cold-shock proteins (notably CspA) bind RNA to promote single-stranded states. - subject: csda_helicase predicate: maintains object: translation_under_cold description: CsdA binds ribosomes to maintain translation under cold shock. evidence: - reference: DOI:10.1007/s12275-023-00031-x notes: CsdA binds ribosomes to maintain translation under cold shock. curation_history: - timestamp: '2026-05-05T01:35:46.843238+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 very limited thermal-adaptation flexibility to the stenothermal temperature-delta-very-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 4 evidence-backed generic edges (6 new nodes) from the deep-research report. llm_assisted: true - timestamp: '2026-06-24T17:21:11Z' curator: claude action: GROUND_CAUSAL_PREDICATES changes: Grounded 1 causal-edge predicate_id field(s) via mappings/predicate_grounding.tsv (RO:0002213×1). 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