identifier: traitmech:000652
label: rosette cell arrangement
definition: A morphological phenotype in which cells form multicellular clusters organized
  around a shared central region, with corresponding cell poles directed inward.
definition_source: DOI:10.7554/eLife.41482
trait_category: MORPHOLOGY
term_kind: CLASS
mapping_status: PROPOSED
parent_traits:
- METPO:1000059
evidence:
- reference: DOI:10.7554/eLife.41482
  snippet: all cells are oriented with their basal poles toward the rosette center
    and their apical flagella extending out from the rosette surface
  notes: Wetzel et al. (2018), PMID:30556809, PMC6322860, first Results subsection;
    full-text XML and Figure 1 directly inspected. Wild-type Salpingoeca rosetta rosettes
    have organized polarity, unlike disordered clumps in the four Class C mutants.
    Methods identify wild type as SrEpac and use Algoriphagus-derived rosette-inducing
    factors. The three-cell minimum after vortexing is this study's scoring rule,
    not a universal definition. Clonal development rather than aggregation is specific
    to S. rosetta here. The Results quote is not the scientific abstract or editorial
    digest.
- reference: DOI:10.1128/jb.00064-19
  snippet: form multicellular rosettes by adhering to each other through the polar
    polysaccharide, or holdfast.
  notes: Fiebig (2019), PMID:31010900, PMC6707911, Results subsection Holdfasts are
    prominent in the pellicle. Publisher HTML, growth/sampling/microscopy Methods,
    and Figure 4 were directly inspected. Static CB15 cultures form rosettes with
    holdfast-rich cores. The Results describe both radial and oblong rosettes; not
    every core is a single attachment point. Supplemental Figure S2's text was accessible
    but its image was not verified. Pellicle dependence on holdfast is not a universal
    rosette mechanism. The Discussion leaves the field relevance of thick Caulobacter
    pellicles unresolved; laboratory observations are not evidence that these structures
    occur in every habitat.
canonical_examples:
- taxon_id: NCBITaxon:946362
  taxon_label: Salpingoeca rosetta
  reference: DOI:10.7554/eLife.41482
  note: 'Wild-type SrEpac (ATCC PRA-390) in rosette-inducing-factor cultures, not
    every life stage. Natural-isolate provenance was checked in Levin and King''s
    Experimental Procedures: https://doi.org/10.1016/j.cub.2013.08.061. SrEpac is
    isolate C, derived from Px1 by feeder replacement, antibiotic treatment and clonal
    isolation; Px1 derives from environmental rosette isolate ATCC 50818. It is not
    the EMS-mutagenized isolate B. The provenance citation is not counted as independent
    trait evidence. NCBI Taxonomy resolves the species ID and label.'
discussions:
- discussion_id: rosette-cell-arrangement-scope-and-hierarchy
  prompt: Review a multicellular arrangement parent and exact external mappings.
  kind: CURATION_TODO
  status: OPEN
  rationale: Retain phenotype METPO:1000059. Cell shape METPO:1000666 describes an
    individual cell, while colony morphology METPO:1007062 and colony shape METPO:1007063
    describe macroscopic colonies on solid medium. Neither is the genus of this microscopic
    multicellular arrangement. Obsolete cell arrangement METPO:1000046 is not a usable
    active parent. Star shaped METPO:1000685 is one cell with radiating projections;
    staphylococcus arrangement traitmech:000118 is an irregular coccal cluster. Holdfast
    traitmech:000184 is a polar adhesin phenotype, not a rosette, and biofilm formation
    traitmech:000053 does not define this arrangement. Co-occurrence is not organism-level
    disjointness. No unqualified synonym, external equivalence, perfect spherical
    symmetry, fixed cell count or single central attachment point is asserted. Irregular
    clumping alone is insufficient.
  posed_by: codex
  posed_date: '2026-10-06'
- discussion_id: rosette-cell-arrangement-mechanism-scope
  prompt: Keep organism-specific developmental and adhesion mechanisms separate.
  kind: KNOWLEDGE_GAP
  status: OPEN
  rationale: The two primary studies support a shared morphological description, not
    one homologous developmental program. Wetzel et al.'s exclusion of aggregation
    concerns S. rosetta rosettes, whereas Fiebig describes polar adhesion in Caulobacter.
    Do not require clonal division or a bacterial holdfast for all rosettes. A causal
    graph is deferred pending separate organism-scoped perturbation and accession
    reviews, not because mechanisms are unknown. Holdfast-associated genes or predicted
    glycosyltransferases alone do not establish the observed arrangement. Quantitative
    shear, growth and cell-number thresholds are assay-specific. Additional bacterial
    canonical examples require strain-provenance and taxon verification; the CB15
    evidence is retained without an unverified taxon row.
  posed_by: codex
  posed_date: '2026-10-06'
curation_history:
- timestamp: '2026-10-06T23:05:49Z'
  curator: codex
  action: MINTED_TRAITMECH_ID
  changes: Added rosette cell arrangement with two DOI-backed Results snippets, a
    provenance-qualified S. rosetta example, and explicit arrangement/mechanism boundaries.
    Ignored-and-hidden novelty searches and structured METPO review found no exact
    record. Reserved METPO:1060500 in v528; existing records unchanged.
  llm_assisted: true