identifier: traitmech:000005
label: pressure range
definition: A pressure phenotype with numerical limits that bounds the minimum and
  maximum hydrostatic pressures supporting growth of an organism.
definition_source: DOI:10.1099/ijsem.0.001671
trait_category: ENVIRONMENT
term_kind: CLASS
mapping_status: REVIEWED
parent_traits:
- METPO:1000059
evidence:
- reference: DOI:10.1099/ijsem.0.001671
  snippet: growth range of 80-140 MPa (optimum, 120 MPa) at 6 degrees C
  notes: Colwellia marinimaniae MTCD1 illustrates a bounded growth-supporting pressure
    span (80-140 MPa), the quantity this phenotype records.
- reference: DOI:10.3389/fmolb.2022.1058381
  snippet: Microorganisms adapted to HHP are usually known as piezophiles, referring
    to their preference for high pressure
  notes: Pressure-adaptation review supports the bounded span of growth-permissive
    hydrostatic pressure as a defining quantitative descriptor.
causal_graphs:
- graph_id: pressure_range_growth_bounded_span
  title: 'Pressure range: bounded hydrostatic-pressure span supporting growth'
  description: Evidence-backed sketch linking the hydrostatic-pressure axis to the
    minimum/maximum bounds within which growth is sustained.
  nodes:
  - node_id: pressure_range_trait
    label: pressure range
    node_type: TRAIT
    grounding: traitmech:000005
    description: Bounded min-to-max hydrostatic pressure supporting growth.
  - node_id: hydrostatic_pressure
    label: hydrostatic pressure
    node_type: ENVIRONMENTAL_FACTOR
    description: Ambient hydrostatic pressure imposed on the cell.
    grounding: PATO:0001025
  - node_id: bounded_growth_span
    label: growth-permissive pressure span
    node_type: QUALITY
    description: Continuous interval of hydrostatic pressures supporting growth.
  - node_id: pufa_biosynthesis
    label: polyunsaturated fatty acid biosynthesis
    node_type: BIOLOGICAL_PROCESS
    description: Synthesis of polyunsaturated fatty acids incorporated into membrane
      lipids.
    grounding: GO:0006636
  - node_id: membrane_fluidity_hhp
    label: membrane fluidity under high hydrostatic pressure
    node_type: QUALITY
    description: Degree of membrane lipid disorder/fluidity maintained against pressure-induced
      ordering.
  - node_id: unsaturated_membrane_lipids
    label: unsaturated membrane lipids
    node_type: CHEMICAL
    description: Unsaturated fatty acids in membrane phospholipids that counter pressure-induced
      ordering.
  - node_id: tmao
    label: trimethylamine N-oxide (TMAO)
    node_type: CHEMICAL
    description: Compatible solute / piezolyte excluded from the protein hydration
      layer.
  - node_id: protein_stabilization
    label: protein stabilization via preferential hydration
    node_type: BIOLOGICAL_PROCESS
    description: Stabilization of native protein structure by preferential exclusion
      of cosolutes.
  - node_id: compatible_solute_accumulation
    label: compatible solute accumulation
    node_type: BIOLOGICAL_PROCESS
    description: Accumulation of compatible solutes (betaine, glutamate, beta-hydroxybutyrate)
      acting as piezolytes.
  edges:
  - subject: hydrostatic_pressure
    predicate: defines
    object: pressure_range_trait
    description: The hydrostatic-pressure axis defines the min/max bounds bracketed
      by the pressure range.
    evidence:
    - reference: DOI:10.3389/fmolb.2022.1058381
      notes: Pressure-adaptation review frames the bounded span of growth-permissive
        pressure as a defining quantitative descriptor.
    predicate_id: METPO:2007500
  - subject: pressure_range_trait
    predicate: associated with
    object: bounded_growth_span
    description: The pressure range records the bounded interval of permissive hydrostatic
      pressures.
    evidence:
    - reference: DOI:10.1099/ijsem.0.001671
      notes: Colwellia marinimaniae MTCD1 illustrates a bounded growth-supporting
        pressure span (80-140 MPa).
    predicate_id: biolink:associated_with
  - subject: pufa_biosynthesis
    predicate: increases
    object: membrane_fluidity_hhp
    description: PUFA biosynthesis increases membrane fluidity to counter pressure-induced
      membrane ordering.
    evidence:
    - reference: DOI:10.3389/fmolb.2022.1058381
      notes: PUFAs (C20:5, C22:6) associated with adaptation to high hydrostatic pressure;
        broad mechanism across taxa.
    predicate_id: RO:0002213
  - subject: unsaturated_membrane_lipids
    predicate: positively regulates
    object: pressure_range_trait
    description: Unsaturated membrane lipids support growth across high hydrostatic
      pressures.
    evidence:
    - reference: DOI:10.3389/fmolb.2022.1058381
      notes: Mutants with reduced C18:1 could not withstand high pressure; unsaturation
        counters pressure ordering.
  - subject: membrane_fluidity_hhp
    predicate: expands
    object: pressure_range_trait
    description: Maintaining membrane fluidity under pressure expands the growth-supporting
      pressure range.
    evidence:
    - reference: DOI:10.3390/microorganisms11071629
      notes: Pressure compacts membranes; organisms restore membrane disorder/function
        via unsaturation to sustain growth.
  - subject: tmao
    predicate: stabilizes
    object: protein_stabilization
    description: TMAO stabilizes proteins via preferential hydration (preferential
      exclusion from hydration layer).
    evidence:
    - reference: DOI:10.1021/acs.chemrev.3c00432
      notes: TMAO preferentially excluded from protein hydration layer causing preferential
        hydration; biophysical mechanism, not microbe-specific.
  - subject: compatible_solute_accumulation
    predicate: stabilizes
    object: protein_stabilization
    description: Compatible solutes stabilize proteins via preferential hydration.
    evidence:
    - reference: DOI:10.3390/microorganisms11071629
      notes: Compatible solutes (glutamate, betaine, beta-hydroxybutyrate) act by
        preferential hydration, displacing protein-bound water.
curation_history:
- timestamp: '2026-05-28T00:00:00Z'
  curator: claude
  action: PROPOSED_FROM_RESEARCH
  changes: Proposed quantitative companion trait (growth-supporting pressure span)
    mirroring the existing temperature_range / nacl_range pattern, to fill the pressure
    coverage gap.
  llm_assisted: true
- timestamp: '2026-06-09T14:00:00Z'
  curator: claude
  action: CURATED_CAUSAL_GRAPH
  changes: Added evidence-backed causal graph (pressure-axis defines bounded growth
    span) with METPO/biolink predicate groundings; promoted PROPOSED to REVIEWED.
  llm_assisted: true
- timestamp: '2026-06-16T06:54:39Z'
  curator: claude
  action: GROUND_CAUSAL_NODES
  changes: Grounded 1 causal-node grounding field(s) via mappings/node_grounding.tsv
    (PATO:0001025×1).
  llm_assisted: true
- timestamp: '2026-06-23T00:00:00Z'
  curator: claude
  action: ENRICH_CAUSAL_GRAPH
  changes: Added 5 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: '2026-06-24T17:23:31Z'
  curator: claude
  action: GROUND_CAUSAL_NODES
  changes: Grounded 1 causal-node grounding field(s) via mappings/node_grounding.tsv
    (GO:0006636×1).
  llm_assisted: true