identifier: METPO:1000689
label: disc shaped
definition: A cell shape in which an organism is flat and circular.
definition_source: DOI:10.1099/ijs.0.65431-0
trait_category: MORPHOLOGY
term_kind: CLASS
mapping_status: REVIEWED
parent_traits:
- METPO:1000666
synonyms:
- synonym_text: disc
  synonym_type: RELATED_SYNONYM
  source: metpo.owl
evidence:
- reference: DOI:10.1146/annurev-cellbio-101011-155745
  snippet: cell shape is genetically determined
  notes: Cell-shape review supports flat-disc geometry as a determined morphological
    phenotype.
- reference: DOI:10.1099/ijs.0.65431-0
  snippet: flat square or disc-shaped cells
  notes: Halophilic-archaea description supports flat disc-shaped cell morphology
    in the wild.
causal_graphs:
- graph_id: disc_shaped_anisotropic_wall_growth
  title: Disc-shape anisotropic cell-wall growth
  description: DOI-backed graph linking anisotropic, planar peptidoglycan or S-layer
    growth and suppressed axial extension to flat disc-shaped cell geometry.
  nodes:
  - node_id: disc_shaped_trait
    label: disc shaped
    node_type: TRAIT
    grounding: METPO:1000689
    description: Flat, circular cellular morphology.
  - node_id: planar_envelope_growth
    label: planar envelope growth
    node_type: BIOLOGICAL_PROCESS
    description: Cell-envelope (peptidoglycan or S-layer) expansion in a 2D plane.
  - node_id: axial_extension_suppression
    label: axial extension suppression
    node_type: BIOLOGICAL_PROCESS
    description: Reduced or absent extension along the orthogonal cell axis.
  - node_id: flat_geometry
    label: flat disc geometry
    node_type: BIOLOGICAL_PROCESS
    description: Resulting flat, plate-like cell body.
  - node_id: slayer_glycoprotein_maturation
    label: S-layer glycoprotein C-terminal processing and lipid anchoring
    node_type: BIOLOGICAL_PROCESS
    description: ArtA peptidase and Pss enzyme dependent C-terminal processing and
      covalent lipid attachment of the surface (S-layer) glycoprotein.
  - node_id: rod_shaped_state
    label: rod-shaped morphology
    node_type: STATE
    description: Elongated rod cell type that disc/plate cells interconvert with.
  edges:
  - subject: planar_envelope_growth
    predicate: causes
    object: flat_geometry
    description: Planar envelope growth produces a 2D-expanded cell body.
    evidence:
    - reference: DOI:10.1099/ijs.0.65431-0
      snippet: flat square or disc-shaped cells
      notes: Supports planar envelope growth producing flat morphology in disc-shaped
        halophiles.
    predicate_id: biolink:causes
  - subject: axial_extension_suppression
    predicate: contributes to
    object: flat_geometry
    description: Suppression of axial extension keeps cells thin.
    evidence:
    - reference: DOI:10.1146/annurev-cellbio-101011-155745
      snippet: cell shape is genetically determined
      notes: Supports anisotropic growth as a control mechanism for cell shape.
    predicate_id: RO:0002326
  - subject: flat_geometry
    predicate: manifests as
    object: disc_shaped_trait
    description: Flat geometry manifests the disc-shaped trait.
    evidence:
    - reference: DOI:10.1099/ijs.0.65431-0
      snippet: disc-shaped cells
      notes: Supports the trait endpoint.
    predicate_id: METPO:2007400
  - subject: slayer_glycoprotein_maturation
    predicate: enables
    object: flat_geometry
    description: C-terminal processing and lipid anchoring of the S-layer glycoprotein
      is required for stable flat plate-shaped cell formation.
    evidence:
    - reference: DOI:10.1099/mic.0.001012
      notes: Required for the C-terminal processing and covalent lipid attachment
        of S-layer glycoprotein, required for effective and stable plate-shaped cell
        formation.
    predicate_id: RO:0002327
  - subject: disc_shaped_trait
    predicate: interconverts with
    object: rod_shaped_state
    description: Disc/plate cell type interconverts with the rod cell type as part
      of regulated shape switching.
    evidence:
    - reference: DOI:10.1038/nature13983
      notes: H. volcanii exhibits interconvertible plate and rod cell types; transition
        from a disk-shape to a rod-shape.
curation_history:
- timestamp: '2026-05-05T01:35:46.897674+00:00'
  curator: seed_from_metpo
  action: SEEDED_FROM_METPO
  changes: imported from data/raw/metpo.owl (CLASS)
  llm_assisted: false
- timestamp: '2026-05-11T22:45:00-07:00'
  curator: claude
  action: CURATED_CAUSAL_GRAPH
  changes: Added DOI-backed causal graph linking planar envelope growth and axial-extension
    suppression to disc-shaped morphology.
  llm_assisted: true
- timestamp: '2026-05-20T03:35:31Z'
  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: '2026-05-23T21:30:07Z'
  curator: claude
  action: GROUND_CAUSAL_PREDICATES
  changes: Grounded 1 causal-edge predicate_id field(s) via mappings/predicate_grounding.tsv
    (METPO:2007400×1).
  llm_assisted: true
- timestamp: '2026-05-24T04:13:19Z'
  curator: claude
  action: RENAME_PREDICATE_LABELS
  changes: 'Renamed 1 causal-edge predicate label(s) to align with existing groundings:
    shapes → causes ×1.'
  llm_assisted: true
- timestamp: '2026-05-24T04:13:21Z'
  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: '2026-06-23T00:00:00Z'
  curator: claude
  action: ENRICH_CAUSAL_GRAPH
  changes: Added 2 evidence-backed generic edges (2 new nodes) from the deep-research
    report.
  llm_assisted: true
- timestamp: '2026-06-24T17:21:13Z'
  curator: claude
  action: GROUND_CAUSAL_PREDICATES
  changes: Grounded 1 causal-edge predicate_id field(s) via mappings/predicate_grounding.tsv
    (RO:0002327×1).
  llm_assisted: true