TraitMech

TraitMech › PHYSIOLOGY

contact-dependent outer membrane exchange

traitmech:000650 · CLASS · PROPOSED

A physiological phenotype in which microbial cells exchange outer-membrane lipids and proteins with other cells through direct intercellular contact.

Trait evidence (4)

  • DOI:10.7554/eLife.00868
    transient contacts between two cells are sufficient to transfer OM materials, proteins and lipids, at high efficiency.

    PMID:23898400, PMC3721248. Scientific Abstract span directly read in Europe PMC XML, not the eLife digest. Selected Results s2-1 to s2-4 and Methods s4-1 to s4-4 were read; actual Figures 2 and 4 were visually inspected with their captions. Engineered Myxococcus xanthus DZ2 reporters and DiO assays distinguish OM material transfer from inner-membrane reporter exchange. Contact and traA controls support the observed endpoint. Dye continuity through some tubes does not establish significant protein transfer through them, which was not detected. Membrane fusion is the authors' mechanistic interpretation; not every contact transfers material. Videos and remaining supplementary panels were not inspected.

  • DOI:10.1371/journal.pgen.1002626
    By use of a lipophilic fluorescent dye, we also discovered that OM lipids are exchanged.

    PMID:22511878, PMC3325183. Scientific Abstract directly read in Europe PMC XML; Results s2c/s2d and Methods s4a/s4e/s4f also read. Reporter and DiD experiments in M. xanthus support TraA/TraB dependence in donors and recipients under the tested surface-growth conditions. Liquid and nonmotile-pair controls limit inference from dye labeling alone. Similar domain architecture in mxan_4924 did not yield an overt transfer defect when disrupted; sequence resemblance is not sufficient phenotype evidence. Proposed adhesion, fusion and social roles are not all directly established by this study. Actual panels and strain-table provenance remain uninspected.

  • DOI:10.1128/jb.00850-13
    Thus, genetic and environmental conditions that promote OMT production are incongruent with OM exchange.

    PMID:24391054, PMC4011004. Scientific abstract directly retrieved through the Europe PMC core API. Full-text XML retrieval failed, so no full-text or panel verification is claimed. The abstract reports abundant OM tubes in traA/traB mutants and liquid conditions that do not permit transfer. Tube abundance alone is therefore insufficient for this trait; this does not negate the specific dye-conducting connections imaged in 2013. This paper shares investigators with the 2012 study and is not independent-laboratory replication.

  • DOI:10.1371/journal.pone.0224817
    Collectively, our results suggest that most mechanisms of interference competition and inter-colony kin discrimination in natural populations of myxobacteria do not require OME.

    PMID:31774841, PMC6880969. Scientific Abstract and Results sec012/sec014 directly read in Europe PMC XML. In the tested natural-isolate pairs, traA disruption or the A60 deletion did not remove colony-merger incompatibility. This is a boundary on ecological-function claims, not evidence that membrane exchange never occurs. The GJV1 control uses swarm inhibition as an inferred OME-dependent toxin readout, not direct fluorescent membrane transfer in every isolate. The directly read correction DOI:10.1371/journal.pone.0228697 (PMID:31999808, PMC6991971) concerns Table 3 typesetting; no Table 3 numerical claim is used here. Actual panels were not visually inspected.

Provenance

Identifier source
TraitMech local identifier
Definition source
DOI:10.7554/eLife.00868

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 membrane-component exchange distinct from its possible consequences.

CURATION TODO OPEN outer-membrane-exchange-scope-and-mapping · raised by codex · 2026-10-06

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.

The endpoint is contact-dependent exchange of outer-membrane material between cells. It is not cytoplasmic fusion, conjugative DNA transfer, all contact-dependent toxin delivery, or a generic secretion phenotype. Exocytosis traitmech:000637 concerns intracellular-compartment fusion-pore discharge; extracellular membrane vesicle production traitmech:000649 concerns extracellular particles. Neither is an exact parent. Cell-free vesicle transfer and slime-trail deposition do not alone demonstrate this contact-qualified class. The traits may coexist; no organism-level disjointness is asserted. Do not require equal bidirectional flux, transfer of every cargo at every contact, cooperation, killing, kin discrimination or fruiting-body development. Retain phenotype METPO:1000059 pending human hierarchy and external-mapping review; no unqualified exact synonym or external equivalence is asserted.

Ground strain-specific transfer machinery beyond sequence predictions.

KNOWLEDGE GAP OPEN outer-membrane-exchange-strain-and-mechanism-grounding · raised by codex · 2026-10-06

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.

TraA/TraB dependence and live material transfer are supported, but no accession-resolved universal fusogen pathway is asserted. Before adding causal graphs, resolve protein accessions, inspect remaining supplements and distinguish measured transfer, binding and fusion-model steps. PA14/MYXO-CTERM/OmpA-like sequence features or a traAB annotation alone do not establish the phenotype. Reporter-bearing and deletion strains remain qualified evidence, not unqualified natural exemplars. Natural provenance and direct positive transfer evidence must be paired before adding canonical examples; the 2019 negative kin-discrimination result cannot supply that positive anchor. These are outstanding grounding tasks, not a claim that no mechanism is known.

Curation history

  1. · MINTED_TRAITMECH_ID · codex

    Added contact-dependent outer membrane exchange with four DOI-backed snippets and explicit transfer, tube, ecological-function and sequence-inference boundaries. Ignored-and-hidden duplicate searches and the pinned METPO audit found no exact record. Reserved METPO:1060300 in v526. Deferred unresolved strain/protein grounding; existing records are unchanged.