nematode-repelling activity

traitmech:000725 · CLASS · PROPOSED

A physiological capability of a microorganism to elicit active movement of nematodes away from itself or substances it produces.

Trait evidence (2)

DOI:10.1073/pnas.0610281104
C. elegans specifically avoids certain strains of Serratia based on their production of the cyclic lipodepsipentapeptide serrawettin W2.

Pradel et al. 2007, PMID:17267603, PMCID:PMC1892944, scientific Abstract; exact normalized PMC match and native VERIFIED. C. elegans denotes Caenorhabditis elegans. Own Results and actual Figures 1-4 distinguish initial entry followed by leaving Serratia marcescens lawns from absence of attraction. A swrA insertion mutant shows reduced lawn leaving but similar multiday killing; reduced avoidance is not loss of pathogenicity. Purified serrawettin W2 on E. coli OP50 lawns and acute drop-induced reversal are separate assays. The 16-hour bacterial-lawn endpoint, 60-minute supplemented-lawn endpoint and acute reversal are not one exposure. Chemical recognition versus a mechanical surfactant cue remains unresolved, and other bacterial cues can contribute. Serratia swrA is not the similarly named Bacillus motility regulator.
DOI:10.15252/embj.2020106938
a specific volatile organic compound, 1‐undecene, produced by the pathogen P. aeruginosa is sensed as an aversive signal by C. elegans.

Prakash et al. 2021, PMID:34086368, PMCID:PMC8246062, Discussion first paragraph, own-study result; directly matched JATS, PMC and publisher text. Native NOT_IN_ABSTRACT is retained, not relabeled VERIFIED. This is its own experiment, not a citation of Pradel. P. aeruginosa denotes Pseudomonas aeruginosa. Figure 1A-B measures PA14 lawn occupancy over 12 hours. Pure 1-undecene gives negative chemotaxis and omega turns in distinct Figure 2 and Appendix S2 assays. PA14-versus-undA odor choice establishes relative preference, not by itself repulsion or complete loss of bacterial repellence. Peer-review reply page 14 reports reversals but no complete lawn leaving after 1-undecene on OP50; the alternative adjacent-lawn crossing assay is not eviction from an occupied lawn. Roaming or higher mean square displacement alone is not directional avoidance. Recipient sensory genetics is not a microbial causal pathway.

Provenance

Identifier source: TraitMech local identifier
Definition source: DOI:10.1073/pnas.0610281104

Parent traits (1)

phenotype METPO:1000059

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.

Refine the hierarchy without confusing microbial repellence with recipient behavior or microbial taxis.

CURATION TODO OPEN nematode-repelling-activity-scope-and-hierarchy · raised by codex · 2026-10-14

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 bearer is a microorganism capable of eliciting active nematode movement away. Lack of attraction, relative food preference alone, paralysis, killing, feeding, trapping or altered egg hatching is insufficient. Infection, benefit to the microbe and prior ingestion are not required. No organism-level disjointness from attraction or lethality is asserted: responses depend on strain, recipient and conditions. Phenotype METPO:1000059 is the conservative parent. Pinned/current releases and inspected editor/template owners have no exact counterpart identified. Deprecated chemotaxis METPO:1000062 has no replacement or consider annotation in the inspected ontology and concerns the moving organism, not this microbial capability. It is not revived or used as a mapping. The v601 proposal retains PROPOSED status; no exact synonym or external equivalence is asserted.

Resolve assay conditions, host range and strain provenance before adding canonical examples or causal edges.

KNOWLEDGE GAP OPEN nematode-repelling-activity-source-and-mechanism-limits · raised by codex · 2026-10-14

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.

Two bacterial studies support the capability, not a shared molecule or universal nematode response. Gene presence or compound production alone cannot establish repellence. No canonical taxon, protein, chemical xref or causal graph is asserted without authority checks. Prakash Appendix S1A depicts a 22-hour incubation then a 2-hour, 37 C step, whereas main Methods describes 22 hours followed by one hour at room temperature; these are not harmonized into one headspace condition. Added recipient alleles and controls in peer review do not establish a successful AWB ablation or blanket physiological specificity. Neither study proves universal nonlethality, field efficacy, environmental safety or therapeutic use. Own results, methods and selected figures/supplement/replies were inspected, not all raw data. Source URLs, hashes, direct snippet checks and bounded correction/retraction searches are retained in the verification sidecar; no comprehensive notice clearance is claimed.

Curation history

2026-10-14T09:11:26Z · MINTED_TRAITMECH_ID · codex
Added microbial nematode-repelling activity with two primary DOI studies and directly checked 18-word and 21-word snippets. Preserved native VERIFIED/NOT_IN_ABSTRACT outcomes and distinct lawn-leaving, reversal, chemotaxis and relative-preference endpoints. Reserved 000725, v601 and 1067800-1067899 after ignored/hidden current-copy, retained-history and open/draft PR checks. Decimal embedding values and broad editor ranges are not conflicting reservations. No exact active METPO counterpart or same-scope node migration identified in inspected owners; no canonical examples or shared mechanism inferred. Other records unchanged. Timestamp records observed acceptance.

Recorded curation sessions

2026-10-14T09:16:02Z · codex
- CREATE — Add nematode-repelling activity
  Added one PROPOSED microbial capability eliciting active nematode movement away from itself or its products. Pradel 2007 supplies definition support; Prakash 2021 supplies a second primary experiment. Directly checked 18-word and 21-word snippets retain native VERIFIED and NOT_IN_ABSTRACT outcomes. Lawn leaving, acute reversal, pure-compound chemotaxis and relative odor preference remain separate endpoints. No universal host range, shared mechanism, canonical taxa, chemical/protein xrefs, causal graph, nonlethality or field efficacy inferred. Ignored/hidden current-copy, retained-history and open/draft PR checks found no exact counterpart or competing allocation in documented scope. Two embedding coordinates and 857 broad editor-envelope matches were adjudicated as false positives. Reserved local 000725, v601 and the full 1067800-1067899 block. Trait timestamp records observed acceptance; this event records later CREATE. All preexisting records including protected spore germination remain unchanged.
Read this curation session