identifier: METPO:1000684
label: spiral shaped
definition: A cell shape in which an organism has a spiral or helically curved morphology
  rather than a straight rod or sphere.
definition_source: DOI:10.1371/journal.pbio.1002565
trait_category: MORPHOLOGY
term_kind: CLASS
mapping_status: REVIEWED
parent_traits:
- METPO:1000666
synonyms:
- synonym_text: S_curved_spiral
  synonym_type: RELATED_SYNONYM
  source: metpo.owl
- synonym_text: spiral
  synonym_type: RELATED_SYNONYM
  source: metpo.owl
- synonym_text: spiral-shaped
  synonym_type: RELATED_SYNONYM
  source: metpo.owl
created_by: Luke Wang
evidence:
- reference: DOI:10.1371/journal.pbio.1002565
  snippet: spirillar types
  notes: Supports spiral/spirillar morphology as a recognized bacterial cell-shape
    class within broader bacterial morphology diversity.
canonical_examples:
- taxon_id: NCBITaxon:1085
  taxon_label: Rhodospirillum rubrum
  note: "Classic spiral (helically twisted) bacterium; purple non-sulfur photosynthesis model."
  reference: PMID:21886856
causal_graphs:
- graph_id: spiral_shaped_curvature_mechanisms
  title: Spiral-shape curvature and cell-wall mechanism
  description: Evidence-backed causal sketch linking spiral morphology to scaffold-mediated
    curvature, peptidoglycan remodeling, and helical/spiral cell geometry.
  nodes:
  - node_id: spiral_shaped_trait
    label: spiral shaped
    node_type: TRAIT
    grounding: METPO:1000684
    description: Spiral or helically curved bacterial morphology.
  - node_id: peptidoglycan_remodeling
    label: peptidoglycan remodeling
    node_type: BIOLOGICAL_PROCESS
    description: Local cell-wall synthesis, relaxation, or crosslink remodeling.
  - node_id: curvature_scaffold
    label: curvature scaffold
    node_type: GENE_OR_PROTEIN
    description: Protein scaffold or shape complex that biases cell curvature.
  - node_id: helical_curvature
    label: helical curvature
    node_type: BIOLOGICAL_PROCESS
    description: Curved and twisted cell-wall geometry.
  - node_id: viscous_motility_environment
    label: viscous motility environment
    node_type: ENVIRONMENTAL_FACTOR
    description: Viscous surroundings where curved or helical morphology can affect
      movement.
  - node_id: pg_crosslink_relaxation
    label: peptidoglycan crosslinking relaxation
    node_type: BIOLOGICAL_PROCESS
    description: Reduction in peptidoglycan crosslinking density that loosens the
      sacculus.
  - node_id: biased_outer_curve_pg_biosynthesis
    label: biased outer-curve peptidoglycan biosynthesis
    node_type: BIOLOGICAL_PROCESS
    description: A longitudinal zone of elevated peptidoglycan insertion along the
      outer cell curve.
  - node_id: cell_curvature
    label: cell curvature
    node_type: QUALITY
    description: Bending of the cell-wall cylinder producing a curved or helical cell
      axis.
  - node_id: elongasome_entrapment
    label: elongasome entrapment
    node_type: BIOLOGICAL_PROCESS
    description: Caging of the cell-elongation machinery that restricts where peptidoglycan
      is inserted.
  - node_id: periplasmic_flagella
    label: periplasmic flagella
    node_type: ORGANELLE
    description: Endoflagella running within the periplasm of spirochetes that mechanically
      couple to the cell body.
  - node_id: cell_body
    label: cell body
    node_type: CELLULAR_LOCALIZATION
    description: The bacterial cell body (protoplasmic cylinder) whose shape is mechanically
      constrained.
    grounding: GO:0044297
  edges:
  - subject: curvature_scaffold
    predicate: regulates
    object: peptidoglycan_remodeling
    description: Shape scaffolds or complexes bias wall remodeling to create curved
      and spiral forms.
    evidence:
    - reference: DOI:10.1371/journal.pbio.1002565
      snippet: cytoplasmic scaffolding proteins ... participate in helical morphogenesis
      notes: Supports scaffold involvement in helical or spiral morphogenesis.
    predicate_id: RO:0002211
  - subject: peptidoglycan_remodeling
    predicate: enables
    object: helical_curvature
    description: Peptidoglycan remodeling enables helical curvature and twist.
    evidence:
    - reference: DOI:10.1016/j.cell.2010.03.046
      snippet: relaxes peptidoglycan crosslinking, enabling helical cell curvature
        and twist
      notes: H. pylori provides a source-backed concrete mechanism for spiral-like
        helical morphology.
    predicate_id: RO:0002327
  - subject: helical_curvature
    predicate: produces
    object: spiral_shaped_trait
    description: Helical curvature produces a spiral-shaped cell body.
    evidence:
    - reference: DOI:10.1371/journal.pbio.1002565
      snippet: helical cells
      notes: Supports helical/spiral cell shape as a recurring bacterial morphology.
    predicate_id: METPO:2000202
  - subject: spiral_shaped_trait
    predicate: associated with
    object: viscous_motility_environment
    description: Spiral and curved morphologies can be associated with motility in
      viscous media.
    evidence:
    - reference: DOI:10.1371/journal.pbio.1002565
      snippet: helical and curved cells appear to be optimized for motility
      notes: Functional association is broad and marked as an association, not as
        a universal cause of the trait.
    predicate_id: biolink:associated_with
  - subject: pg_crosslink_relaxation
    predicate: promotes
    object: helical_curvature
    description: Relaxation of peptidoglycan crosslinking promotes helical/spiral
      shape.
    evidence:
    - reference: DOI:10.3389/fmicb.2023.1162806
      notes: Peptidoglycan crosslinking relaxation promotes helical shape and colonization.
    predicate_id: RO:0002213
  - subject: elongasome_entrapment
    predicate: biases
    object: biased_outer_curve_pg_biosynthesis
    description: Caging/entrapment of the elongasome biases peptidoglycan insertion
      toward the outer curve.
    evidence:
    - reference: DOI:10.1038/s41467-024-51790-z
      notes: Porin-PapS assemblies entrap the cell elongation machinery, biasing peptidoglycan
        insertion toward the outer curve.
  - subject: biased_outer_curve_pg_biosynthesis
    predicate: establishes
    object: cell_curvature
    description: A zone of elevated outer-curve peptidoglycan biosynthesis distorts
      the wall cylinder and establishes curvature.
    evidence:
    - reference: DOI:10.1038/s41467-024-51790-z
      notes: Creating a longitudinal zone of elevated peptidoglycan biosynthesis distorts
        the cell-wall cylinder and establishes curvature; ~15% bias suffices.
  - subject: cell_curvature
    predicate: produces
    object: spiral_shaped_trait
    description: Sustained cell curvature produces a spiral/helically curved cell.
    evidence:
    - reference: DOI:10.1038/s41467-024-51790-z
      notes: Curvature established by biased outer-curve growth yields curved/helical
        cell morphology.
    predicate_id: METPO:2000202
  - subject: periplasmic_flagella
    predicate: maintains
    object: spiral_shaped_trait
    description: Periplasmic flagella serve as a cytoskeleton that maintains the spiral-shaped
      cell body.
    evidence:
    - reference: DOI:10.3390/biom14121488
      notes: The periplasmic flagella serves as a cytoskeleton to maintain a spiral-shaped
        cell body.
  - subject: periplasmic_flagella
    predicate: distorts
    object: cell_body
    description: Periplasmic flagellar filaments distort and push the cell body to
      shape it.
    evidence:
    - reference: DOI:10.1093/pnasnexus/pgad349
      notes: Spirochete flagella inside the periplasm distort and push the cell body.
curation_history:
- timestamp: '2026-05-05T01:35:46.894976+00:00'
  curator: seed_from_metpo
  action: SEEDED_FROM_METPO
  changes: imported from data/raw/metpo.owl (CLASS)
  llm_assisted: false
- timestamp: '2026-05-11T18:00:00-07:00'
  curator: codex
  action: CURATED_WITH_LITERATURE
  changes: Added definition and DOI-backed causal graph for spiral morphology, peptidoglycan
    remodeling, curvature scaffolds, helical curvature, and viscous motility association.
  llm_assisted: true
- timestamp: '2026-05-20T03:35:31Z'
  curator: claude
  action: GROUND_CAUSAL_PREDICATES
  changes: Grounded 2 causal-edge predicate_id field(s) via mappings/predicate_grounding.tsv
    (RO:0002327×1, METPO:2000202×1).
  llm_assisted: true
- timestamp: '2026-05-20T05:49:24Z'
  curator: claude
  action: GROUND_CAUSAL_PREDICATES
  changes: Grounded 1 causal-edge predicate_id field(s) via mappings/predicate_grounding.tsv
    (biolink:associated_with×1).
  llm_assisted: true
- timestamp: '2026-05-26T05:00:48Z'
  curator: claude
  action: RENAME_PREDICATE_LABELS
  changes: 'Renamed 1 causal-edge predicate label(s) to align with existing groundings:
    influences → regulates ×1.'
  llm_assisted: true
- timestamp: '2026-05-26T05:00:51Z'
  curator: claude
  action: GROUND_CAUSAL_PREDICATES
  changes: Grounded 1 causal-edge predicate_id field(s) via mappings/predicate_grounding.tsv
    (RO:0002211×1).
  llm_assisted: true
- timestamp: '2026-06-23T00:00:00Z'
  curator: claude
  action: ENRICH_CAUSAL_GRAPH
  changes: Added 6 evidence-backed generic edges (6 new nodes) from the deep-research
    report.
  llm_assisted: true
- timestamp: '2026-06-24T17:21:14Z'
  curator: claude
  action: GROUND_CAUSAL_PREDICATES
  changes: Grounded 2 causal-edge predicate_id field(s) via mappings/predicate_grounding.tsv
    (RO:0002213×1, METPO:2000202×1).
  llm_assisted: true
- timestamp: '2026-06-24T17:23:34Z'
  curator: claude
  action: GROUND_CAUSAL_NODES
  changes: Grounded 1 causal-node grounding field(s) via mappings/node_grounding.tsv
    (GO:0044297×1).
  llm_assisted: true