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mucocyst discharge

traitmech:000684 · CLASS · PROPOSED

An exocytotic phenotype in which a microbial cell releases mucocyst contents to the exterior through fusion of a mucocyst membrane with the plasma membrane.

Trait evidence (3)

  • DOI:10.1371/journal.pgen.1010194
    lysosome-related organelles called mucocysts accumulate at the cell periphery where they secrete their contents in response to extracellular events

    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.

  • DOI:10.1016/0309-1651(77)90012-1
    Synchronous secretion of all available mature mucocysts was induced

    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.

  • DOI:10.1128/ec.00058-15
    those cores do not undergo normal directional expansion during exocytosis, and they thus fail to efficiently extrude from the cells.

    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.

Provenance

Identifier source
TraitMech local identifier
Definition source
DOI:10.1371/journal.pgen.1010194

Parent traits (1)

kg-microbe context

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

Discussions and Knowledge Gaps (2)

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

Keep cargo release distinct from organelle presence and homologous types.

CURATION TODO OPEN mucocyst-discharge-scope-and-homology · raised by codex · 2026-10-08

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.

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.

Resolve natural culture provenance and taxon-specific release mechanisms.

KNOWLEDGE GAP OPEN mucocyst-discharge-provenance-and-mechanism · raised by codex · 2026-10-08

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.

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.

Curation history

  1. · MINTED_TRAITMECH_ID · codex

    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.

Recorded curation sessions

  • · codex
    • CREATE — Add evidence-backed mucocyst discharge

      Created traitmech:000684 with three primary DOI scientific-abstract snippets, qualified assay proxies and homologous extrusome terminology, unresolved natural strain provenance and deferred protein mechanism. Reserved v560 METPO:1063700-1063799 with explicit exocytosis v513 dependency; existing records unchanged.

    Read this curation session