identifier: METPO:1000627
label: euryhaline
definition: A halophily preference in which an organism can tolerate a wide range
  of salinity conditions.
definition_source: DOI:10.5928/kaiyou.14.337
trait_category: ENVIRONMENT
term_kind: CLASS
mapping_status: REVIEWED
parent_traits:
- METPO:1000629
evidence:
- reference: DOI:10.5928/kaiyou.14.337
  snippet: growing over a salinity range of 15%
  notes: Supports euryhaline halophiles as organisms growing across a wide salinity
    range.
- reference: PMID:22675587
  snippet: due to its strong euryhaline phenotype
  notes: 'Organism example: Chromohalobacter salexigens is described as having a strong
    euryhaline phenotype.'
canonical_examples:
- taxon_id: NCBITaxon:666
  taxon_label: Vibrio cholerae
  note: "tolerates a broad salinity range"
  reference: PMID:14532045
- taxon_id: NCBITaxon:2746
  taxon_label: Halomonas elongata
  note: "euryhaline halophile"
  reference: PMID:35432243
causal_graphs:
- graph_id: euryhaline_wide_salinity_tolerance
  title: Euryhaline wide-salinity tolerance mechanism
  description: Evidence-backed causal sketch linking euryhalinity to broad salinity
    ranges, osmotic imbalance, compatible solutes, and salinity-adaptation genes.
  nodes:
  - node_id: euryhaline_trait
    label: euryhaline
    node_type: TRAIT
    grounding: METPO:1000627
    description: Tolerance of a wide range of salinity conditions.
  - node_id: wide_salinity_range
    label: wide salinity range
    node_type: ENVIRONMENTAL_FACTOR
    description: Environmental salinity range broad enough to require flexible osmoadaptation.
  - node_id: salinity_gradient
    label: salinity gradient
    node_type: ENVIRONMENTAL_FACTOR
    description: Spatial or temporal gradient from low to high salinity.
  - node_id: osmotic_imbalance
    label: osmotic imbalance
    node_type: BIOLOGICAL_PROCESS
    description: Difference between external and internal osmotic potential.
  - node_id: compatible_solutes
    label: compatible solutes
    node_type: CHEMICAL
    description: Organic osmolytes accumulated to adjust cell osmotic potential.
    grounding: CHEBI:25728
  - node_id: compatible_solute_transport
    label: compatible-solute transport
    node_type: MOLECULAR_FUNCTION
    description: Uptake of osmoprotectants from the environment.
  - node_id: salinity_adaptation_genes
    label: salinity-adaptation genes
    node_type: GENE_OR_PROTEIN
    description: Gene families associated with microbial salinity adaptation across
      gradients.
  - node_id: choline
    label: choline
    node_type: CHEMICAL
    description: Precursor metabolite converted to glycine betaine.
    grounding: CHEBI:15354
  - node_id: glycine_betaine
    label: glycine betaine
    node_type: CHEMICAL
    description: Compatible solute / osmoprotectant accumulated under salt stress.
    grounding: CHEBI:17750
  - node_id: glycine_betaine_biosynthesis
    label: glycine betaine biosynthesis
    node_type: BIOLOGICAL_PROCESS
    description: Two-step oxidative conversion of choline to glycine betaine by BetA/BetB.
    grounding: GO:0031456
  - node_id: ectoine
    label: ectoine
    node_type: CHEMICAL
    description: Compatible solute widely implicated in halophily and salinity tolerance.
    grounding: CHEBI:22563
  - node_id: ectoine_biosynthesis
    label: ectoine biosynthesis
    node_type: BIOLOGICAL_PROCESS
    description: Five-step biosynthesis of ectoine from L-aspartate (lysC/asd/ectB/ectA/ectC).
    grounding: GO:0019491
  - node_id: mechanosensitive_channels
    label: mechanosensitive channels (Msc)
    node_type: GENE_OR_PROTEIN
    description: Channels acting as safety valves releasing ions and solutes during
      osmotic downshock.
  - node_id: osmotic_downshock
    label: osmotic downshock
    node_type: BIOLOGICAL_PROCESS
    description: Sudden drop in external salinity causing rapid water influx and turgor
      rise.
  - node_id: na_h_antiporter
    label: Na+/H+ antiporter
    node_type: GENE_OR_PROTEIN
    description: Antiporter that expels sodium ions from the cytoplasm.
    grounding: UniProtKB:A0A068T423
  - node_id: cytoplasmic_sodium
    label: cytoplasmic sodium ions
    node_type: CHEMICAL
    description: Intracellular Na+ that must be exported to maintain ion homeostasis.
    grounding: CHEBI:29101
  - node_id: proteome_acidification
    label: proteome acidification
    node_type: BIOLOGICAL_PROCESS
    description: Increased proportion of acidic amino acids improving protein solubility
      at high ionic strength.
  edges:
  - subject: wide_salinity_range
    predicate: defines
    object: euryhaline_trait
    description: Euryhaline organisms tolerate or grow across broad salinity ranges.
    evidence:
    - reference: DOI:10.5928/kaiyou.14.337
      snippet: growing over a salinity range of 15%
      notes: Communication proposes a quantitative characterization for euryhaline
        halophiles.
    predicate_id: METPO:2007500
  - subject: salinity_gradient
    predicate: selects for
    object: euryhaline_trait
    description: Variable salinity environments select for broad salinity tolerance.
    evidence:
    - reference: DOI:10.1186/s40168-024-01817-w
      snippet: salinity gradient of a typical short residence-time estuary
      notes: Estuary metagenome study uses salinity gradients to analyze microbial
        salinity adaptation.
    predicate_id: METPO:2007401
  - subject: salinity_gradient
    predicate: causes
    object: osmotic_imbalance
    description: Movement across salinity gradients changes osmotic pressure on the
      cell.
    evidence:
    - reference: DOI:10.1186/s40168-024-01817-w
      snippet: water immediately rushes into the cell
      notes: Supports osmotic imbalance and water flux during salinity change.
    predicate_id: biolink:causes
  - subject: compatible_solute_transport
    predicate: imports
    object: compatible_solutes
    description: Euryhaline tolerance can use flexible uptake of osmoprotectants.
    evidence:
    - reference: DOI:10.1016/j.csbj.2021.01.030
      snippet: biosynthesis and/or uptake of compatible solutes
      notes: Review supports compatible-solute uptake and biosynthesis as bacterial
        salt-stress responses.
    predicate_id: METPO:2000208
  - subject: compatible_solutes
    predicate: mitigates
    object: osmotic_imbalance
    description: Compatible solutes help balance external osmotic pressure across
      changing salinity.
    evidence:
    - reference: DOI:10.1186/1746-1448-1-5
      snippet: balance external osmotic pressure
      notes: Supports compatible solutes as osmolytes under salinity stress.
    predicate_id: METPO:2007407
  - subject: salinity_adaptation_genes
    predicate: contributes to
    object: euryhaline_trait
    description: Salinity-adaptation gene repertoires contribute to broad salinity
      tolerance.
    evidence:
    - reference: DOI:10.1186/s40168-024-01817-w
      snippet: genes associated with microbial salinity adaptation
      notes: Supports salinity-adaptation genes as contributors to microbial salinity
        niche breadth.
    predicate_id: RO:0002326
  - subject: glycine_betaine_biosynthesis
    predicate: produces
    object: glycine_betaine
    description: Choline is oxidized to glycine betaine in two steps by BetA and BetB.
    evidence:
    - reference: DOI:10.3389/fmicb.2023.1192059
      notes: Choline is transformed into glycine betaine in two oxidative steps carried
        out by BetA (K00108) and BetB (K00130).
    predicate_id: METPO:2000202
  - subject: choline
    predicate: is precursor of
    object: glycine_betaine
    description: Choline serves as the substrate for glycine betaine biosynthesis.
    evidence:
    - reference: DOI:10.3389/fmicb.2023.1192059
      notes: Choline is transformed into glycine betaine in two oxidative steps (BetA/BetB).
  - subject: glycine_betaine
    predicate: mitigates
    object: osmotic_imbalance
    description: Glycine betaine accumulates as a compatible solute to balance osmotic
      pressure.
    evidence:
    - reference: DOI:10.3389/fmicb.2023.1192059
      notes: Glycine betaine is a compatible solute used in the salt-out osmoadaptation
        strategy.
    predicate_id: METPO:2007407
  - subject: ectoine_biosynthesis
    predicate: produces
    object: ectoine
    description: Ectoine is synthesized from L-aspartate in five steps (lysC/asd/ectB/ectA/ectC).
    evidence:
    - reference: DOI:10.3389/fmicb.2023.1192059
      notes: Ectoine is obtained from L-aspartate in five steps mediated by lysC,
        asd, ectB, ectA, and ectC.
    predicate_id: METPO:2000202
  - subject: ectoine
    predicate: mitigates
    object: osmotic_imbalance
    description: Ectoine acts as an osmoprotective compatible solute under salinity
      stress.
    evidence:
    - reference: DOI:10.3389/fmicb.2023.1192059
      notes: Ectoine widely implicated in halophily and salinity tolerance; protects
        cell components under stress.
    predicate_id: METPO:2007407
  - subject: mechanosensitive_channels
    predicate: responds to
    object: osmotic_downshock
    description: Msc channels serve as safety valves releasing ions and organic solutes
      during sudden downward osmotic shocks.
    evidence:
    - reference: DOI:10.3390/microorganisms12081738
      notes: Msc mechanosensitive channels serve as safety valves, allowing the rapid
        release of ions and organic solutes in the case of sudden downward osmotic
        shocks.
  - subject: na_h_antiporter
    predicate: exports
    object: cytoplasmic_sodium
    description: Na+/H+ antiporters expel sodium ions from the cytoplasm to maintain
      ion homeostasis.
    evidence:
    - reference: DOI:10.3390/microorganisms12081738
      notes: Sodium ions are expelled from the cytoplasm, usually performed with the
        help of Na+/H+ antiporters.
    predicate_id: METPO:2000209
  - subject: proteome_acidification
    predicate: contributes to
    object: euryhaline_trait
    description: Acidification of the proteome improves protein solubility across
      salinity regimes.
    evidence:
    - reference: DOI:10.1126/sciadv.adg2059
      notes: Increase in acidic amino acids (notably glutamate); acidification of
        the proteome essential for protein solubility at higher ionic strength.
    predicate_id: RO:0002326
curation_history:
- timestamp: '2026-05-05T01:35:46.864669+00:00'
  curator: seed_from_metpo
  action: SEEDED_FROM_METPO
  changes: imported from data/raw/metpo.owl (CLASS)
  llm_assisted: false
- timestamp: '2026-05-06T14:15:44-07:00'
  curator: codex
  action: CURATED_WITH_ORGANISM_EXAMPLE
  changes: Added Chromohalobacter salexigens organism example with PMID-backed evidence.
  llm_assisted: true
- timestamp: '2026-05-11T00:00:00-07:00'
  curator: codex
  action: CURATED_WITH_LITERATURE
  changes: Added DOI-backed euryhaline causal graph for broad salinity tolerance,
    salinity gradients, compatible solutes, and salinity-adaptation genes.
  llm_assisted: true
- timestamp: '2026-05-20T03:35:29Z'
  curator: claude
  action: GROUND_CAUSAL_PREDICATES
  changes: Grounded 1 causal-edge predicate_id field(s) via mappings/predicate_grounding.tsv
    (RO:0002326×1).
  llm_assisted: true
- timestamp: '2026-05-20T05:49:23Z'
  curator: claude
  action: GROUND_CAUSAL_PREDICATES
  changes: Grounded 1 causal-edge predicate_id field(s) via mappings/predicate_grounding.tsv
    (biolink:causes×1).
  llm_assisted: true
- timestamp: '2026-05-23T21:30:06Z'
  curator: claude
  action: GROUND_CAUSAL_PREDICATES
  changes: Grounded 2 causal-edge predicate_id field(s) via mappings/predicate_grounding.tsv
    (METPO:2007401×1, METPO:2007407×1).
  llm_assisted: true
- timestamp: '2026-05-24T04:37:59Z'
  curator: claude
  action: GROUND_CAUSAL_NODES
  changes: Grounded 1 causal-node grounding field(s) via mappings/node_grounding.tsv
    (CHEBI:65015×1).
  llm_assisted: true
- timestamp: '2026-05-24T07:37:39Z'
  curator: claude
  action: GROUND_CAUSAL_PREDICATES
  changes: Grounded 1 causal-edge predicate_id field(s) via mappings/predicate_grounding.tsv
    (METPO:2007500×1).
  llm_assisted: true
- timestamp: '2026-06-15T07:19:07Z'
  curator: claude
  action: FIX_NODE_GROUNDING_CURIE
  changes: Overwrote 1 causal-node grounding(s) to corrected CURIEs (phase-2 id-label
    fix; verified vs OAK).
  llm_assisted: true
- timestamp: '2026-06-16T06:30:55Z'
  curator: claude
  action: GROUND_CAUSAL_PREDICATES
  changes: Grounded 1 causal-edge predicate_id field(s) via mappings/predicate_grounding.tsv
    (METPO:2000208×1).
  llm_assisted: true
- timestamp: '2026-06-17T04:09:43Z'
  curator: claude
  action: REMOVE_REDUNDANT_SYNONYM
  changes: Removed 1 synonym(s) whose text duplicated the label (seeder redundancy;
    no information lost).
  llm_assisted: true
- timestamp: '2026-06-23T00:00:00Z'
  curator: claude
  action: ENRICH_CAUSAL_GRAPH
  changes: Added 8 evidence-backed generic edges (10 new nodes) from the deep-research
    report.
  llm_assisted: true
- timestamp: '2026-06-24T17:21:09Z'
  curator: claude
  action: GROUND_CAUSAL_PREDICATES
  changes: Grounded 6 causal-edge predicate_id field(s) via mappings/predicate_grounding.tsv
    (METPO:2000202×2, METPO:2007407×2, METPO:2000209×1, RO:0002326×1).
  llm_assisted: true
- timestamp: '2026-06-24T17:21:16Z'
  curator: claude
  action: GROUND_CAUSAL_NODES
  changes: Grounded 1 causal-node grounding field(s) via mappings/node_grounding.tsv
    (UniProtKB:A0A068T423×1).
  llm_assisted: true
- timestamp: '2026-06-24T17:23:30Z'
  curator: claude
  action: GROUND_CAUSAL_NODES
  changes: Grounded 2 causal-node grounding field(s) via mappings/node_grounding.tsv
    (GO:0031456×1, GO:0019491×1).
  llm_assisted: true