cytostomal cord

cellstructuremech:cytostomal_cord · Cytoskeleton · Filament · Proposed

A largely unbranched, centrin-containing extension of the infraciliary lattice associated with the cytostome-cytopharynx region, characterized in Paramecium. It is a named fibrillar substructure, not the entire lattice or the adjacent cytopharyngeal microtubular ribbons. [DOI:10.1111/j.1550-7408.1998.tb04526.x]

Cytostomal cord and adjacent cross sections of alveolar-sac extensions in Paramecium multimicronucleatum. Source scale bar: 0.5 micrometres. Static anatomy does not demonstrate calcium-triggered cord contraction. TEM · *Paramecium multimicronucleatum* (`NCBITaxon:44030`) · Richard Allen (University of Hawaii); via Cell Image Library · PUBLIC_DOMAIN · source: CELL_IMAGE_LIBRARY CIL:36704 · `DOI:10.7295/W9CIL36704`

Part of: infraciliary lattice (cellstructuremech:infraciliary_lattice); oral apparatus (GO:0031912)

UniProt location names: UniProt Consortium, CC BY 4.0. Reference label and route sources.

Components

Component	Type	Part of / acts on	Grounding	Genes	Stoichiometry	Essential	Role
Cytostomal-cord centrins	Protein	part of	Reviewed label only (reviewed name; no accession asserted)			UNKNOWN	Centrin-family constituents detected by centrin-specific antibody labeling; selective requirements for cord assembly are not established here. `DOI:10.1111/j.1550-7408.1998.tb04526.x` Primary abstract identifies the cord as centrin-specific, like the infraciliary lattice, and immunologically distinct from striated bands. No cord-specific depletion or complete composition is described in the abstract.

Canonical examples

NCBITaxon:5885 Paramecium caudatum — Species used for serial-section electron microscopy in the 1974 Methods. The cord is named and described in the Observations; CIL:36779 also documents it. Exact species identifier verified at ENA. [DOI:10.1083/jcb.63.3.904]
NCBITaxon:44030 Paramecium multimicronucleatum — Organism named by the inspected CIL:36704 TEM record. Source supplies the species name, not a taxid; exact identifier independently verified at ENA. No strain or genus-wide prevalence inferred. [DOI:10.7295/W9CIL36704]

Functions

Roof of cytopharyngeal vesicle-accumulation spaces — In P. caudatum the cord forms the fibrillar roof of boxlike spaces between cytopharyngeal microtubular ribbons, above the membrane where discoidal vesicles accumulate. This is an observed architectural role, not a demonstrated requirement for vesicle retention, transport, fusion or vacuole release.
- DOI:10.1083/jcb.63.3.904 Observations on journal pages 913 and 915 place the cord above the ribbon ends and the accumulating vesicles. Discussion on page 918 treats the cord's active function as unresolved.

Discussions

CURATION_TODO (RESOLVED): Distinguish the named oral cord from the extended infraciliary lattice and other oral or centrin structures. A named localized substructure can have its own record without duplicating its encompassing network.
CURATION_TODO (OPEN): Resolve cord-specific centrin paralogues, scaffold constituents and selective assembly requirements. Shared immunoreactivity does not establish complete molecular identity or requirements inherited from the whole lattice.
CURATION_TODO (OPEN): Test whether cord contraction promotes vesicle fusion or release of nascent food vacuoles, and identify the relevant calcium pathway. Static ultrastructure and centrin localization do not demonstrate an active mechanism or necessity.
CURATION_TODO (RESOLVED): Keep microtubular ribbons, alveolar sacs, striated bands and vesicles outside the cord's molecular composition. Adjacency and shared placement in the oral apparatus do not make other structures constituent proteins or membranes of the cord.
CURATION_TODO (OPEN): Inspect full 1998 experimental text and compare named cytostomal cords outside Paramecium before extending distribution. Names shared across ciliates do not by themselves establish identical molecular composition or topology.

Evidence

DOI:10.1083/jcb.63.3.904 Allen 1974, PMID 4373478, PMC2109358 version 1. Official PDF checksum verified; Methods and cord-specific Observations/Discussion read on PDF pages 2, 10, 12 and 15. PDF pages 15-16 visually inspected. The paper distinguishes observed anatomy from speculative cord function.
DOI:10.1111/j.1550-7408.1998.tb04526.x Allen, Aihara and Fok 1998, PMID 9561774. PubMed and publisher-deposited Crossref abstracts read. Publisher PDF returned HTTP 403; full Methods and figures were not inspected.
DOI:10.7295/W9CIL36704 Source-native caption, public-domain declaration, attribution and organism metadata read; entire TEM inspected. Alveolar-finger association is anatomical evidence; the source explicitly marks the proposed cord contraction and downstream effects as hypothetical.
DOI:10.7295/W9CIL36779 Source-native caption and entire TEM inspected. P. caudatum cord is distinguished from the curving microtubular ribbons and nearby alveolar extensions. CC BY-NC-SA 3.0 asset is not copied into the repository.
GO:0005622 Verified non-obsolete intracellular anatomical structure, used only as broad is-a parent.
GO:0031912 Verified non-obsolete oral apparatus, the encompassing feeding structure; cord location is independently supported by the 1974 primary Observations.

Curation history

2026-10-04T03:03:58Z codex · CREATED_RECORD — Scaffolded by scripts/new_record.py
2026-10-04T03:05:20Z codex · EXPANDED_RECORD — Added scoped primary anatomy and centrin evidence, part-whole hierarchy, verified examples, architectural role, inspected public-domain TEM and explicit molecular, functional and distribution limits.

Source: data/structures/cytoskeleton/cytostomal_cord.yaml