identifier: traitmech:000684
label: mucocyst discharge
definition: An exocytotic phenotype in which a microbial cell releases mucocyst contents
  to the exterior through fusion of a mucocyst membrane with the plasma membrane.
definition_source: DOI:10.1371/journal.pgen.1010194
trait_category: PHYSIOLOGY
term_kind: CLASS
mapping_status: PROPOSED
parent_traits:
- traitmech:000637
evidence:
- reference: DOI:10.1371/journal.pgen.1010194
  snippet: lysosome-related organelles called mucocysts accumulate at the cell periphery
    where they secrete their contents in response to extracellular events
  notes: PMID:35587496, PMC9159632. Scientific Abstract, relevant Results/Methods
    and Discussion read directly in Europe PMC fullTextXML and publisher HTML. Figure
    1 and its caption were visually inspected; Figure 4 caption, not image, was read.
    The snippet is from the scientific Abstract, not the Author summary. Dibucaine
    stimulates release in Tetrahymena thermophila. Sedimented flocculent volume is
    a secretion proxy, not a count of discharged organelles; cells can be trapped
    in that layer. The MN175 missense and MDL1 deletion phenotypes differ. S1 Table
    DOCX text was inspected, not rendered; laboratory strain names and genotypes do
    not establish natural provenance.
- reference: DOI:10.1016/0309-1651(77)90012-1
  snippet: Synchronous secretion of all available mature mucocysts was induced
  notes: PMID:610868. Scientific Abstract directly retrieved with EXT_ID:610868 AND
    SRC:MED in Europe PMC; an unqualified numeric query also returns an unrelated
    database record. The correct MED result matches this DOI and title. Abstract-only
    access; full Methods and figures were not inspected. The source names Tetrahymena
    thermophilia (B III). Synchrony and complete release concern late-log cultures
    treated with dibucaine, not universal requirements for this trait. Fusion-rosette
    reappearance and new mucocyst precursors are temporally associated, not proof
    of a universal protein mechanism.
- reference: DOI:10.1128/ec.00058-15
  snippet: those cores do not undergo normal directional expansion during exocytosis,
    and they thus fail to efficiently extrude from the cells.
  notes: 'PMID:26092918, PMC4519746. Scientific Abstract directly retrieved by exact
    quoted DOI query in Europe PMC. Abstract-only access; full Methods, figures and
    supplements were not inspected. The snippet refers to CTH4-disrupted Tetrahymena
    thermophila: crystalline cores assemble but extrusion is inefficient. It is boundary
    evidence distinguishing assembly from successful release, not a positive mutant
    exemplar or proof that no cargo is released. CTH4 dependence is not imposed on
    all mucocysts.'
discussions:
- discussion_id: mucocyst-discharge-scope-and-homology
  prompt: Keep cargo release distinct from organelle presence and homologous types.
  kind: CURATION_TODO
  status: OPEN
  rationale: Exocytosis traitmech:000637 is the broader parent; the proposal depends
    on its v513 placeholder METPO:1059000. Mucocyst formation, docking and fusion
    without cargo release do not alone establish discharge. Lysis and preparation
    artifacts must be excluded from positive assays. Neither rapid expansion nor total
    emptying defines this class. The 2022 Discussion calls Paramecium trichocysts
    mucocyst homologs. This record preserves the organelle-specific release phenotype
    rather than asserting independent origins, exact equivalence to trichocyst discharge
    traitmech:000683, or organism-level disjointness. Resolve historical extrusome
    terminology before broadening the definition; not all mucus secretion, cortical
    granules or capsule formation are equivalent. No exact synonyms or xrefs are asserted.
  posed_by: codex
  posed_date: '2026-10-08'
- discussion_id: mucocyst-discharge-provenance-and-mechanism
  prompt: Resolve natural culture provenance and taxon-specific release mechanisms.
  kind: KNOWLEDGE_GAP
  status: OPEN
  rationale: These experiments support a secretion phenotype in source-named Tetrahymena
    systems, not every protist bearing an extrusome. Natural culture provenance and
    strain-level taxonomy remain unchecked, so no canonical examples are assigned.
    A wildtype designation alone does not establish natural provenance; a mutant designation
    alone does not establish engineering. The MDL1 and CTH4 experiments motivate a
    future protein-resolved graph, but require taxon-paired accessions and separation
    of maturation, docking, fusion and cargo extrusion. Mechanism is deferred, not
    claimed absent; sequence features alone do not establish discharge. Do not infer
    a universal ecological role from induced secretion.
  posed_by: codex
  posed_date: '2026-10-08'
curation_history:
- timestamp: '2026-10-08T17:15:26Z'
  curator: codex
  action: MINTED_TRAITMECH_ID
  changes: Added mucocyst discharge with three primary DOI sources and directly checked
    scientific-abstract snippets. Ignored-and-hidden main/worktree/open-PR checks
    support 000684 and v560 block 1063700-1063799. Used existing exocytosis parent
    and its v513 proposal dependency. Qualified assay proxies, organelle homology,
    mutant evidence and provenance; deferred protein mechanism. Existing records unchanged.
    Timestamp is observed UTC.
  llm_assisted: true