palmelloid formation

traitmech:000654 · CLASS · PROPOSED

A morphological phenotype in which algal cells form nonmotile multicellular groups by retention within a mother-cell wall or by adhesion through extracellular gelatinous material.

Trait evidence (3)

DOI:10.3390/ijms24098374
the cells continue to divide within the mother cell, i.e., they are unable to separate and remain encased in a single membrane.

Suwannachuen et al. (2023), PMID:37176080, PMC10179368, Discussion 3.3. The quote is the authors' interpretation of enclosed dividing cells, not an abstract quote or a specific molecular mechanism. Results 2.5 and actual Figure 10 show CC-4414 palmelloids after high-light exposure in TAP medium. Methods 4.2 defines the percentage as palmelloid area divided by total cell area, not an individual-cell count. Larger aggregates are distinguished from palmelloids. CC-4414 provenance remains qualified in the discussion below.
DOI:10.3389/fpls.2022.911035
a morphological state characterized by multiple, single cells encased in an outer limiting membrane

Szyszka-Mroz et al. (2022), PMID:36119589, PMC9470844, Introduction. The scientific abstract, growth Methods, morphology Results and actual Figure 1 were inspected. Palmelloids occur alongside single cells at permissive 8 C; stress is not a necessary condition. Internal cells may retain flagella. Shared enclosure does not establish a particular membrane chemistry or universal cytokinesis defect.
DOI:10.1038/s41598-019-39558-8
the production of a gelatinous material that is secreted extracellularly, resulting in adhesion among cells and/or colonies

Herron et al. (2019), PMID:30787483, PMC6382799, Discussion. Directly retrieved full text explicitly uses palmelloid for both mother-wall retention and extracellular-material-mediated adhesion. This quote supports the second sense. The adjacent text describes palmelloids as nonmotile. This is terminology evidence, not a claim that the selected evolved isolates are natural canonical examples. The narrower enclosed-cell usage in the 2022/2023 sources is retained with its source attribution.

Provenance

Identifier source: TraitMech local identifier
Definition source: DOI:10.1038/s41598-019-39558-8

Parent traits (1)

phenotype METPO:1000059

kg-microbe context

No kg-microbe node embedding matched this record in the 2026-04-25 deepwalk.

Canonical examples (1)

Organisms cited as exemplars of this trait. Taxon ids are NCBITaxon and link out to the NCBI record.

Chlamydomonas priscui NCBITaxon:1653778 DOI:10.3389/fpls.2022.911035 Lake Bonney Antarctic isolate grown at 8 C in Bold's basal medium supplemented with 0.7 M NaCl, at 150 micromol photons m^-2 s^-1. Figure 1A,B and morphology Results show a mixed population of single cells and palmelloids, not every cell or growth stage. The Introduction identifies its natural lake origin. The source uses Chlamydomonas priscuii; NCBI Taxonomy lists that spelling as a synonym of the current species label Chlamydomonas priscui.

Discussions and Knowledge Gaps (3)

Open questions attached to this trait. Seeded by just knowledge-gap-scan and curated; see the corpus-wide index.

Review a multicellular morphology parent and exact mappings.

CURATION TODO OPEN palmelloid-formation-scope-and-hierarchy · raised by codex · 2026-10-07

Not yet attached to a section of this record — a curator sets attaches_to (e.g. causal_graphs#some_edge) so the gap shows beside the mechanism it concerns.

Herron et al. (2019) explicitly includes mother-wall retention and extracellular-gelatinous-material adhesion in palmelloid usage, whereas the 2022/2023 sources emphasize enclosed cells. Preserve both documented senses in the unqualified class; review whether separate children are warranted. Retain phenotype METPO:1000059: cell shape METPO:1000666 describes an individual cell and colony morphology METPO:1007062 is macroscopic. Obsolete cell arrangement METPO:1000046 and aggregate METPO:1000011 are not active parents. Biofilm formation traitmech:000053 requires surface attachment; rosette cell arrangement traitmech:000652 requires inward cell-pole orientation. Neither is required here. Palmelloid is not an exact synonym for any microbial aggregate, capsule, resting spore or normal transient pre-release sporangium. No xref or organism-level disjointness is asserted.

Resolve organism-specific cell-release mechanisms before graphing.

KNOWLEDGE GAP OPEN palmelloid-formation-mechanism-scope · raised by codex · 2026-10-07

Not yet attached to a section of this record — a curator sets attaches_to (e.g. causal_graphs#some_edge) so the gap shows beside the mechanism it concerns.

A causal graph is deferred pending organism-specific perturbation and protein accession review. The 2023 proteome associations and proposed photoprotection do not establish that particular proteins cause palmelloid formation or that palmelloids are necessary for all high-light tolerance. Gene possession alone does not establish the phenotype. Do not transfer a cell-release mechanism to the extracellular-adhesion form. Four-to-sixteen cells, stress induction, loss of flagella, photoprotection and a particular cytokinesis or wall-remodelling defect are not universal requirements. For the wall-retained form, distinguish sustained enclosure from an ordinary division stage using organism-specific time courses; no universal persistence cutoff is asserted.

Reconcile CC-4414 provenance before canonical-example promotion.

CURATION TODO OPEN palmelloid-formation-cc4414-provenance · raised by codex · 2026-10-07

Not yet attached to a section of this record — a curator sets attaches_to (e.g. causal_graphs#some_edge) so the gap shows beside the mechanism it concerns.

The 2023 paper and Chlamydomonas Resource Center describe CC-4414/DN2 as a field isolate: https://www.chlamycollection.org/product/cc-4414-wild-type-mt-dn2/ . However, Flowers et al. (2015), Results accompanying Figure 2, reports extensive identity-by-descent with laboratory strains and raises possible cross-contamination while retaining a distinct chromosome-16 segment: https://academic.oup.com/plcell/article/27/9/2353/6206349 . Both primary passages were directly read. This is a provenance uncertainty, not proof of engineering or contamination in the 2023 experimental stock. Preserve the observed high-light phenotype as qualified evidence, but omit CC-4414 from canonical examples pending reconciliation.

Curation history

2026-10-07T00:44:51Z · MINTED_TRAITMECH_ID · codex
Added palmelloid formation with two DOI-backed snippets, a condition-qualified Antarctic-isolate example, and explicit enclosure, mechanism and CC-4414 provenance boundaries. Ignored-and-hidden searches and structured METPO review found no exact record. Reserved METPO:1060700 in v530; existing records unchanged.
2026-10-07T00:57:34Z · CORRECTED_DEFINITION_SCOPE · codex
Addressed issue #1767: the unqualified palmelloid label was narrower than documented usage. Added DOI:10.1038/s41598-019-39558-8 and its verified snippet, broadened the definition to include extracellular-material adhesion, and retained source-specific scope and mechanism distinctions. Canonical example unchanged.

Recorded curation sessions

2026-10-07T00:47:14Z · codex
- CREATE — Add evidence-backed palmelloid formation trait
  Added traitmech:000654 palmelloid formation as a PROPOSED morphology class under METPO:1000059, with two directly verified DOI-backed full-text snippets, a condition-qualified NCBITaxon:1653778 Chlamydomonas priscui example, and three open discussions on hierarchy, mechanism and CC-4414 provenance. Whole-repository ignored-and-hidden searches, fresh seeding, release tables, parsed ontology, upstream templates and all-state GitHub searches found no exact record or reservation collision. Companion v530 reserves METPO:1060700. The writer dry run, 20 focused tests and direct LinkML/strict checks passed; generated artifacts, broad validation and PR review are pending at event creation. No existing trait record was changed.
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2026-10-07T00:59:27Z · codex
- EDIT — Correct palmelloid definition to cover both documented senses
  Addresses issue #1767. The initial unqualified definition covered only mother-wall retention. Directly retrieved Herron et al. (2019), DOI:10.1038/s41598-019-39558-8, Discussion explicitly also includes extracellular gelatinous material causing adhesion. Broadened the definition and v530 proposal, added a verified 17-word snippet, and revised scope/mechanism discussions while retaining the qualified Antarctic canonical example. The guarded writer preserves the first curation event and appends CORRECTED_DEFINITION_SCOPE. The original CREATE record history/records/palmelloid_formation/2026-10-07T004714Z-codex-8e7daa.yaml remains accurate about the initial state and is unchanged. Twenty-four revised writer tests and dry run passed; final artifact regeneration, corpus validation and PR review remain pending. The obsolete validation process was deliberately terminated and is not claimed as a complete pass.
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