TraitMech

TraitMech › PHYSIOLOGY

gravikinesis

traitmech:000585 · CLASS · PROPOSED

A motile phenotype in which the speed of active propulsion is modulated according to orientation relative to gravity.

Trait evidence (2)

  • DOI:10.2187/bss.20.44
    We confirmed the gravikinesis from the analysis on the swimming of single cells.

    Abstract; full publisher PDF inspected at https://www.jstage.jst.go.jp/article/bss/20/2/20_2_44/_pdf. Methods and Results (pages 45-46, Table 1) distinguish active propulsion from passive drift using subsequent 10-18 mM NiCl2 immobilization of the same cell. The drift controls retained contractile-vacuole activity and lacked visible deformation. Curved-swimmer responses reverse in 72% Percoll; straight-swimmer responses were not significant. Results N=55 and Table 1 straight-swimmer N=57 are unreconciled; no aggregate sample count is asserted. Table and method pages were visually checked.

  • DOI:10.1007/s001140050634
    The resulting potential-induced modulation of the speed of propulsion is called gravikinesis because it acts to neutralize, fully or in part, sedimentation.

    Publisher abstract and Europe PMC PMID:11536922 checked. Orientation-dependent membrane-potential changes support a physiological component of propulsion control in Paramecium. The sedimentation-opposing response described here is not a universal sign convention or proof of one receptor in all taxa. The subscription full text was not inspected; no strain, channel accession or full-text-only measurement is inferred.

Provenance

Identifier source
TraitMech local identifier
Definition source
DOI:10.2187/bss.20.44

Parent traits (1)

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.

  • Paramecium caudatum NCBITaxon:5885 DOI:10.2187/bss.20.44 Curved-swimming cells from 14-20-day early-stationary hay-infusion cultures at 24 C, adapted to KCM (pH 7.2) and selected beneath the water surface. Table 1 supports gravity-dependent active propulsion in the control hypo-density medium. Swimming was recorded before nickel immobilization, which supplied only the passive-drift correction. This is not a universal cell-state claim. NCBI identifier is species-level; no strain accession is supplied.

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 propulsion modulation distinct from orientation and passive drift.

CURATION TODO OPEN gravikinesis-speed-and-direction-boundaries · raised by codex · 2026-10-04

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.

Observed upward/downward speed differences alone can arise from sedimentation or flotation; the trait concerns the active propulsion component. Gravitaxis (traitmech:000584) denotes directional bias, and gyrotaxis (traitmech:000583) denotes torque-mediated orientation. These can coexist with gravikinesis; no equivalence, disjointness or parent-child relation among them is asserted. The definition does not require faster upward swimming in every medium. Reconcile sign conventions and source-qualified response classes before adding narrower terms or equivalent external mappings.

Resolve exact protein and taxon anchors for a mechanistic graph.

CURATION TODO OPEN gravikinesis-mechanism-grounding · raised by codex · 2026-10-04

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.

Mechanism evidence exists: Gebauer's abstract links orientation to membrane potential and propulsion, while Takeda discusses mechanosensitive conductances and ciliary control. The inspected sources do not identify a sequence-resolved gravity receptor. Takeda treats hydraulic pressure as a candidate stimulus needing amplification, not a demonstrated complete molecular pathway. A graph is deferred pending eligible taxon-paired protein examples and source-bounded causal edges. Do not substitute an unrelated channel or classify this physiological mechanism as NONMECHANISTIC to avoid the protein-coverage gate.

Curation history

  1. · MINTED_TRAITMECH_ID · codex

    Added gravikinesis with two primary DOI sources, contiguous snippets and a drift-corrected Paramecium caudatum example at verified species taxon 5885. Ignored-and-hidden searches found only gravitaxis boundary mentions, not an exact trait or METPO term. Reserved METPO:1053900 in proposal v462; kept direction, passive drift, source sample counts and unresolved protein-level mechanism separate.