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temperature range mid4

METPO:1000453 · CLASS · REVIEWED

A temperature range phenotype in which the growth-supporting ambient temperature range spans approximately 34–40 °C, characteristic of warm-mesophilic physiology (including many mammalian host-associated bacteria).

Temperature-range-mid4 warm-mesophile range

DOI-backed graph linking warm-mesophile adaptation to a temperature growth range of approximately 34–40 °C.

Temperature-range-mid4 warm-mesophile range Interactive directed graph showing evidence-backed causal relationships for temperature range mid4.

Edge evidence

  • warm-mesophile adaptation confers temperature range mid4 METPO:2007700

    Warm-mesophile adaptation enables growth across 34–40 °C.

    • DOI:10.1146/annurev-micro-091313-103612 more unsaturated fatty acids Supports warm-mesophile homeoviscous adaptation as the range mechanism.
  • temperature range mid4 is a temperature range rdfs:subClassOf

    Temperature range mid4 is a quantitative bin of the temperature-range phenotype.

    • DOI:10.1016/s0300-9629(97)00003-0 adapted to environments of high temperature Supports the 34–40 °C range as a value within the temperature-range distribution.
  • FabI/FabB fatty-acid branchpoint valve enables homeoviscous adaptation RO:0002327

    The FabI/FabB branchpoint valve reallocates flux between saturated and unsaturated fatty acid synthesis, enabling homeoviscous adaptation.

    • DOI:10.1038/s41467-024-53677-5 A temperature-sensitive metabolic valve at the fatty-acid branchpoint reallocates flux between saturated and unsaturated fatty acid synthesis via FabI and FabB.
  • FabA/FabI/FabB competition for C10:1 pool regulates membrane lipid composition RO:0002211

    Competition of FabA/FabI/FabB for the common C10:1 pool shifts flux between saturated and unsaturated fatty acids, changing membrane lipid composition.

    • DOI:10.1038/s41467-024-53677-5 FabA, FabI and FabB compete for a common C10:1 pool forming a metabolic valve that shifts flux between saturated and unsaturated fatty acids.
  • membrane fluidity restoration enables growth after temperature shock RO:0002327

    Valve plus transcriptional feedback restores optimal membrane fluidity within a single generation, supporting growth after a temperature shock.

    • DOI:10.1038/s41467-024-53677-5 Restores optimal membrane fluidity within a single generation after a temperature shock.
  • heat stress causes protein unfolding and aggregation biolink:causes

    High temperatures cause protein unfolding and aggregation.

    • DOI:10.1186/s12864-023-09266-9 High temperatures cause a suite of problems for cells, including protein unfolding and aggregation.
  • protein unfolding and aggregation causes impaired mesophile growth biolink:causes

    Protein unfolding and aggregation impairs mesophile growth unless compensated.

    • DOI:10.1186/s12864-023-09266-9 General mechanistic background applicable to the warm-mesophile upper range; protein damage impairs growth unless compensated.
  • heat stress causes membrane fluidity biolink:causes

    High temperatures increase membrane fluidity, requiring compensatory adaptation.

    • DOI:10.1186/s12864-023-09266-9 High temperatures cause a suite of problems for cells, including increased membrane fluidity.
  • membrane fluidity requires compensatory membrane adaptation

    Temperature-driven increase in membrane fluidity requires compensatory adaptation.

    • DOI:10.1186/s12864-023-09266-9 Increased membrane fluidity at high temperature requires compensatory adaptation to maintain function.
  • sigma-32 (RpoH) heat-shock regulon induces DnaK/DnaJ/GrpE and GroES/GroEL chaperone systems

    The sigma-32/RpoH regulon induces the DnaK/DnaJ/GrpE and GroES/GroEL chaperone systems.

    • DOI:10.1128/mbio.03105-23 The alternative sigma factor sigma-32 (RpoH) drives protective heat shock proteins including the DnaK/DnaJ/GrpE and GroES/GroEL chaperone systems.
  • DnaK/DnaJ/GrpE and GroES/GroEL chaperone systems enables protection against heat stress RO:0002327

    The DnaK/DnaJ/GrpE and GroES/GroEL chaperone systems protect against heat stress.

    • DOI:10.1128/mbio.03105-23 Canonical heat-response: chaperone systems refold stress-damaged proteins to protect against heat stress.

Provenance

Source
METPO (2025-11-25)
Definition source
DOI:10.1146/annurev-micro-091313-103612

Parent traits (1)

Synonyms (2)

  • Mesophilie EXACT_SYNONYM · metpo.owl
  • TR_34_to_40 RELATED_SYNONYM · metpo.owl

kg-microbe context

Matched 1 kg-microbe node via direct_metpo.

  • METPO:1000453 [-2.152, +0.301, -2.280, +3.386, …]

512-dim DeepWalkSkipGramEnsmallen embedding from kg-microbe (2026-04-25).

Nearest neighbors in embedding space

Top-8 cosine-similar METPO traits from the 2026-04-25 deepwalk (512-D).

Deep research

Generated by just research-trait; source: research/traits/environment/temperature_range_mid4-deep-research-falcon.md

Unreviewed literature output — not curated TraitMech content Ontology identifiers suggested below have not been resolved against their ontologies, and some are known to be wrong. Check any CURIE against the source before using it. 
# Curation-focused research report: **temperature range mid4**

## 1. Trait scope

**Trait:** `temperature range mid4`  
**Identifier:** `METPO:1000453`  
**Parent:** `METPO:1000306`  
**Category:** environment  
**Definition supplied for curation:** growth-supporting ambient-temperature range spanning approximately **34–40 °C**, characteristic of warm-mesophilic physiology, including many mammalian host-associated bacteria.

This trait should represent an **assay-observed capacity for net microbial growth over a temperature interval**, not merely survival after temperature exposure. Ideally, assignment should be supported by growth curves, colony formation, biomass accumulation, or repeated-transfer data at temperatures spanning or substantially overlapping 34–40 °C. It does not imply that every temperature in that interval is optimal.

### Boundaries and exclusions

* **Optimum versus range:** A reported optimum of 37 or 40 °C alone does not prove a growth-supporting range of 34–40 °C. Cardinal-temperature data—minimum, optimum, and maximum—or measurements at multiple temperatures are preferable.
* **Heat-shock response:** Transient induction of chaperones after a thermal upshift is not itself this phenotype. Acute heat shock can occur inside or outside an organism’s normal growth range.
* **Thermotolerance/thermoduricity:** Survival at 40 °C or after brief exposure to substantially higher temperatures does not establish sustained growth.
* **Thermophily:** A recent experimental-evolution paper operationally defined thermophiles as organisms with growth optima above 45 °C and mesophiles as having optima of 25–45 °C. Accordingly, `METPO:1000453` is a narrow warm-mesophile range class, not a generic thermophile class. (lehmann2023adaptivelaboratoryevolution pages 6-7)
* **Host-temperature sensing:** A shift to approximately 37 °C can activate virulence programs in pathogens, but that regulatory response should only enter this graph where it demonstrably contributes to growth or fitness across the target range. (samtani2022microbialmechanismsof pages 1-3)

## 2. Current mechanistic interpretation

The most defensible general mechanism is **temperature-dependent maintenance of membrane physical state**. Cooling orders the lipid bilayer, whereas warming increases fluidity. Microbes alter lipid unsaturation, branching, chain length, cyclization, and lipid-class abundance to keep membrane properties within a functional window. This preserves transport, respiration, permeability barriers, and membrane-protein activity. The *Bacillus subtilis* DesK–DesR–Des pathway supplies unusually strong causal evidence because membrane composition can activate the pathway at a constant 37 °C; thus DesK senses membrane physical state rather than temperature as an isolated variable. (mendoza2014temperaturesensingby pages 5-6)

A second module is **proteostasis**. Thermal upshifts increase protein damage and misfolding, inducing chaperones and proteases. Nevertheless, most retrieved chaperone evidence concerns acute heat stress rather than constitutive warm-mesophile growth. It should therefore be treated as a supporting or boundary-protection module, not automatically as the core cause of `METPO:1000453`. (samtani2022microbialmechanismsof pages 1-3)

## 3. Candidate graph nodes

### Environmental and assay nodes

* `METPO:1000453` — temperature range mid4, quoted verbatim as requested.
* Ambient temperature, 34–40 °C — label-only range node unless the project has an established temperature-bin vocabulary.
* Temperature decrease / cold shift.
* Temperature increase / thermal upshift.
* Sustained microbial growth — candidate grounding: `GO:0016049` (cell growth), subject to ontology-policy review.
* Acute heat shock — candidate biological-process grounding: `GO:0009408` (response to heat).
* Growth medium composition, oxygen availability, pH, incubation duration, inoculum state, and growth endpoint — experimental covariates that can shift observed temperature boundaries.

### Cellular structures and physical-state nodes

* Cytoplasmic membrane — `GO:0005886`.
* Membrane fluidity / membrane order — label-only physical-state nodes; avoid conflating them with membrane organization.
* Proton-motive force — `GO:0015988` is a possible process-level grounding for proton-motive-force-driven ATP synthesis, but a label-only “proton motive force” node may be more exact.
* Protein folding — `GO:0006457`.
* Protein aggregation / misfolded-protein burden — use label-only unless the exact intended ontology class is verified.

### Lipids and metabolites

* Unsaturated fatty acids — `CHEBI:27283`.
* Saturated fatty acids — `CHEBI:26607`.
* Branched-chain fatty acids — label-only candidate.
* Anteiso-branched-chain fatty acids — label-only candidate.
* Ladderane fatty acids/lipids — label-only candidate; taxon-specific to anammox Planctomycetota.
* Plasmalogens — `CHEBI:17762`.
* Oleic acid — `CHEBI:16196`, if a source specifically demonstrates its role.

### Genes, proteins, and complexes

**Strong *B. subtilis* module**

Showing the first 60 of 188 lines of findings; the linked file also carries the run's front matter and the prompt it was given — read the full report.

Curation history

  1. · SEEDED_FROM_METPO · seed_from_metpo

    imported from data/raw/metpo.owl (CLASS)

  2. · CURATED_CAUSAL_GRAPH · claude

    Added DOI-backed definition and causal graph linking warm-mesophile adaptation to the temperature-range-mid4 bin.

  3. · GROUND_CAUSAL_PREDICATES · claude

    Grounded 2 causal-edge predicate_id field(s) via mappings/predicate_grounding.tsv (RO:0002327×1, rdfs:subClassOf×1).

  4. · ENRICH_CAUSAL_GRAPH · claude

    Added 9 evidence-backed generic edges (14 new nodes) from the deep-research report.

  5. · GROUND_CAUSAL_PREDICATES · claude

    Grounded 7 causal-edge predicate_id field(s) via mappings/predicate_grounding.tsv (RO:0002327×3, biolink:causes×3, RO:0002211×1).

  6. · GROUND_CAUSAL_NODES · claude

    Grounded 1 causal-node grounding field(s) via mappings/node_grounding.tsv (METPO:1007505×1).

  7. · MIGRATE_ENABLES_TRAIT_EDGES · claude

    Migrated 1 causal edge(s) off enables/RO:0002327 with a TRAIT object (1 to confers), issue 302. RO:0002327 has range 'biological process or activity', which a trait (a disposition) cannot satisfy, so the previous form entailed trait is-a BiologicalProcessOrActivity. The replacements are proposed in proposals/metpo_traitmech_v8 and are placeholder ids until METPO mints them.