identifier: METPO:1000446 label: temperature optimum mid4 definition: A temperature optimum phenotype with the best-growth ambient temperature between approximately 34 and 40 °C, characteristic of warm-mesophilic physiology (including many mammalian host-associated bacteria). definition_source: DOI:10.1146/annurev-micro-091313-103612 trait_category: ENVIRONMENT term_kind: CLASS mapping_status: REVIEWED parent_traits: - METPO:1000304 synonyms: - synonym_text: Mesophilie synonym_type: EXACT_SYNONYM source: metpo.owl - synonym_text: TO_34_to_40 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 a 34–40 °C optimum as the warm-mesophile (mammalian-host) setpoint. causal_graphs: - graph_id: temperature_optimum_mid4_warm_mesophile title: Temperature-optimum-mid4 warm-mesophile setpoint description: DOI-backed graph linking warm-mesophile membrane and enzyme adaptation to a temperature optimum between 34 and 40 °C. nodes: - node_id: temperature_optimum_mid4_trait label: temperature optimum mid4 node_type: TRAIT grounding: METPO:1000446 description: Temperature optimum approximately 34–40 °C. - node_id: temperature_optimum label: temperature optimum node_type: TRAIT grounding: METPO:1000304 description: Ambient temperature supporting maximal growth. - node_id: warm_environment label: warm host-associated environment node_type: ENVIRONMENTAL_FACTOR description: Habitat ambient temperature in the 34–40 °C range, typical of many mammalian hosts. - node_id: warm_mesophile_adaptation label: warm-mesophile adaptation node_type: BIOLOGICAL_PROCESS description: Membrane and enzyme repertoires tuned for warm host-body temperatures. - node_id: temperature_downshift label: temperature downshift node_type: ENVIRONMENTAL_FACTOR description: A decrease in ambient growth temperature. - node_id: unsaturated_fatty_acid_proportion label: unsaturated fatty acid proportion node_type: CHEMICAL description: Proportion of unsaturated fatty acids in membrane phospholipids. - node_id: membrane_fluidity_homeostasis label: membrane fluidity homeostasis node_type: BIOLOGICAL_PROCESS description: Maintenance of optimal membrane fluidity (homeoviscous adaptation). - node_id: unsaturated_fa_biosynthesis_response label: unsaturated fatty acid biosynthesis response node_type: BIOLOGICAL_PROCESS description: Upregulation of unsaturated fatty acid biosynthesis upon sensed membrane rigidification. - node_id: rna_thermometer label: RNA thermometer hairpin node_type: GENE_OR_PROTEIN description: Cis-regulatory mRNA hairpin (e.g. ROSE/FourU) controlling translation by temperature. - node_id: shine_dalgarno_sequence label: Shine-Dalgarno / AUG ribosome binding site node_type: GENE_OR_PROTEIN description: Ribosome-binding region of mRNA required for translation initiation. - node_id: temperature_upshift label: temperature upshift / heat shock node_type: ENVIRONMENTAL_FACTOR description: An increase in ambient temperature, including heat shock. - node_id: translation_initiation label: ribosome binding and translation initiation node_type: BIOLOGICAL_PROCESS description: Binding of the ribosome to mRNA and initiation of translation. - node_id: dnak_chaperone label: DnaK chaperone node_type: GENE_OR_PROTEIN description: Hsp70-family chaperone that binds and sequesters the heat-shock sigma factor RpoH. - node_id: rpoh_sigma_factor label: RpoH (sigma-32) heat-shock sigma factor node_type: GENE_OR_PROTEIN description: Alternative sigma factor directing the heat-shock response regulon. - node_id: ftsh_protease label: FtsH protease node_type: GENE_OR_PROTEIN description: ATP-dependent membrane protease that controls RpoH protein levels. grounding: UniProtKB:A0A0D7UY21 edges: - subject: warm_environment predicate: engages object: warm_mesophile_adaptation description: Warm host-associated environments engage warm-mesophile adaptation. evidence: - reference: DOI:10.1146/annurev-micro-091313-103612 snippet: more unsaturated fatty acids notes: Supports homoviscous adaptation at warm-mesophilic temperatures. - subject: warm_mesophile_adaptation predicate: produces object: temperature_optimum_mid4_trait description: Warm-mesophile adaptation yields a 34–40 °C optimum. evidence: - reference: DOI:10.1146/annurev-micro-091313-103612 snippet: more unsaturated fatty acids notes: Supports the 34–40 °C optimum as the warm-mesophile outcome. predicate_id: METPO:2000202 - subject: temperature_optimum_mid4_trait predicate: is a object: temperature_optimum description: Temperature optimum mid4 is a quantitative bin of the temperature-optimum phenotype. evidence: - reference: DOI:10.1016/s0300-9629(97)00003-0 snippet: adapted to environments of high temperature notes: Supports the 34–40 °C optimum as a value within the temperature-optimum distribution. predicate_id: rdfs:subClassOf - subject: temperature_downshift predicate: increases object: unsaturated_fatty_acid_proportion description: Temperature downshift increases the proportion of unsaturated fatty acids (homeoviscous adaptation). evidence: - reference: DOI:10.1146/annurev-micro-091313-103612 notes: Bacteria perform homeoviscous adaptation by incorporating proportionally more unsaturated fatty acids as growth temperature decreases. predicate_id: RO:0002213 - subject: unsaturated_fatty_acid_proportion predicate: maintains object: membrane_fluidity_homeostasis description: Increased unsaturated fatty acids maintain membrane fluidity homeostasis. evidence: - reference: DOI:10.1146/annurev-micro-091313-103612 notes: Disrupting bilayer order optimizes cellular processes at the new temperature; membrane fluidity homeostasis. - subject: membrane_fluidity_homeostasis predicate: induces object: unsaturated_fa_biosynthesis_response description: Sensed decreases in membrane fluidity induce the unsaturated fatty acid biosynthesis response. evidence: - reference: DOI:10.1146/annurev-micro-091313-103612 notes: Microbes sense decreases in membrane fluidity and initiate responses that upregulate biosynthesis of unsaturated fatty acids. - subject: rna_thermometer predicate: occludes object: shine_dalgarno_sequence description: RNA thermometer hairpins occlude the Shine-Dalgarno/AUG region, repressing translation at low temperature. evidence: - reference: DOI:10.1007/s12275-023-00031-x notes: ROSE and FourU RNA thermometers form inhibitory hairpins that cover Shine-Dalgarno/AUG. - subject: temperature_upshift predicate: melts object: rna_thermometer description: Temperature upshift / heat shock melts RNA thermometer structures. evidence: - reference: DOI:10.1007/s12275-023-00031-x notes: RNA thermometers are stable at low temperatures but undergo conformational change (melting) at heat shock. - subject: rna_thermometer predicate: enables object: translation_initiation description: Melting of the RNA thermometer exposes the ribosome binding site and enables translation initiation. evidence: - reference: DOI:10.1007/s12275-023-00031-x notes: Melting releases translation inhibition, allowing ribosome binding and translation initiation. predicate_id: RO:0002327 - subject: dnak_chaperone predicate: negatively regulates object: rpoh_sigma_factor description: DnaK binds and retains RpoH, negatively regulating the heat-shock sigma factor. evidence: - reference: DOI:10.1007/s12275-023-00031-x notes: DnaK binds and retains RpoH until heat-denatured proteins displace it. - subject: ftsh_protease predicate: controls abundance of object: rpoh_sigma_factor description: FtsH protease controls RpoH protein levels. evidence: - reference: DOI:10.1007/s12275-023-00031-x notes: ATP-dependent proteases FtsH and ClpXP control RpoH protein levels. curation_history: - timestamp: '2026-05-05T01:35:46.821571+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 warm-mesophile adaptation to the temperature-optimum-mid4 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 8 evidence-backed generic edges (11 new nodes) from the deep-research report. llm_assisted: true - timestamp: '2026-06-24T17:21:11Z' curator: claude action: GROUND_CAUSAL_PREDICATES changes: Grounded 2 causal-edge predicate_id field(s) via mappings/predicate_grounding.tsv (RO:0002213×1, RO:0002327×1). llm_assisted: true - timestamp: '2026-06-26T07:15:18Z' curator: claude action: GROUND_CAUSAL_NODES changes: Grounded 1 causal-node grounding field(s) via mappings/node_grounding.tsv (UniProtKB:A0A0D7UY21×1). llm_assisted: true