pusule

cellstructuremech:pusule · Membrane organelle · Membrane bounded organelle · Proposed

A dinoflagellate membrane organelle connected to a flagellar canal, comprising sacs, tubules or collecting chambers with associated diverticula. Its wall includes an invaginated plasma membrane apposed to vacuolar membrane; the canal-connected lumen is not a sealed intracellular compartment. [DOI:10.1007/BF01279820]

Polykrikos kofoidii, Figure 2. D: transverse and longitudinal TEM sections of the pusule collecting duct and diverticula (2 micrometer scale bars). E: interior FIB-SEM surface reconstruction. G-H: orange pusule in cellular context (5 micrometer bars). A-C and F depict nuclear features, not pusule anatomy; the nucleus, fibrous ribbon and flagellar rootlets are not pusule components. OTHER · *Polykrikos kofoidii* (`NCBITaxon:271679`) · Gregory S. Gavelis, Maria Herranz, Kevin C. Wakeman, Christina Ripken, Satoshi Mitarai, Gillian H. Gile, Patrick J. Keeling, Brian S. Leander; CC BY, via PubMed Central · CC_BY_4_0 · source: PMC PMC6351617.1 Fig2 · `DOI:10.1038/s41598-018-37065-w`

Synonyms: pusule apparatus

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
membrane	Other	part of	`GO:0016020`			UNKNOWN	Apposed plasma and vacuolar membranes form the pusular wall. `DOI:10.1007/BF01279820` Publisher summary describes this membrane arrangement; full text was not accessible.

Canonical examples

NCBITaxon:271679 Polykrikos kofoidii — Wild-collected pseudocolonies examined by TEM and FIB-SEM. Figure 2D-E shows the collecting duct and associated diverticula; G-H locates the pusule beside the nucleus. [DOI:10.1038/s41598-018-37065-w]
NCBITaxon:2945 Prorocentrum micans — Armored species in the tracer study; publisher-deposited abstract read via Crossref, not the full paper. [DOI:10.1139/b87-098]
NCBITaxon:2961 Amphidinium carterae — Unarmored species in the tracer and serial-section TEM study; abstract-only access. [DOI:10.1139/b87-098]

Discussions

CURATION_TODO (RESOLVED): Keep the pusule distinct from the contractile vacuole and the nuclear net. Similar names or spatial proximity do not establish equivalent structures.
CURATION_TODO (OPEN): Resolve physiological transport functions and molecular constituents with direct evidence. Tracer entry into a surface-connected lumen is not evidence of transmembrane transport.

Evidence

DOI:10.1007/BF01279820 Dodge (1972), Protoplasma. Primary publisher summary read; morphology varies between tubular, sac and vesicle-associated forms. Publisher offers only a subscription preview; PDF and discovery routes did not yield readable full text. No numerical dimensions imported.
DOI:10.1139/b87-098 Klut, Bisalputra and Antia (1987), Canadian Journal of Botany. Crossref publisher abstract reports horseradish peroxidase, cationized ferritin and lectins entering pusules via the flagellar canal in both species. Publisher HTML/PDF routes returned 403 and title searches yielded citations, not full text. No cytoplasmic delivery or nutrient assimilation inferred.
DOI:10.1038/s41598-018-37065-w Gavelis et al. (2019), Scientific Reports. Primary Results, collection Methods and Figure 2 read through PMC BioC/JATS; figure visually inspected. Elaborate plasma-membrane infoldings are identified as pusules. Collecting-duct and diverticular topology is visible without implying a transport mechanism.
GO:0043227 Broad membrane-bounded-organelle parent verified in QuickGO; membrane-bounded does not assert that the lumen is closed. The record denotes the entire pusular apparatus, not the plasma membrane alone.

Curation history

2026-10-03T16:41:23Z codex · CREATED_RECORD — Scaffolded by scripts/new_record.py
2026-10-03T16:42:47Z codex · EXPANDED_RECORD — Added source-bounded membrane anatomy, three verified species examples, physiological uncertainty, identity boundaries and inspected CC BY microscopy provenance.

Source: data/structures/membrane_organelle/pusule.yaml