non motile

Deep research

Generated by just research-trait; source: research/traits/morphology/non_motile-deep-research-falcon.md

# Curation-Focused Report: Microbial Trait Non-Motile (METPO:1000703)

## 1. Trait Scope Summary

The microbial trait **non-motile** (METPO:1000703) is defined as "a motility in which an organism lacks the ability to move independently under its own power." The trait represents the **phenotypic absence of active, self-propelled displacement** observable under specified assay and environmental conditions (guan2024flhfaffectsthe pages 1-2, guan2024flhfaffectsthe pages 2-6, warrell2024interspeciessurfactantsservea pages 1-2, warrell2024interspeciessurfactantsservea pages 5-7). 

### Boundary Cases and Distinctions

The non-motile phenotype must be carefully distinguished from several related states:

1. **Aflagellate vs. paralyzed flagella:** Non-motile cells may completely lack flagellar structures (e.g., ΔfliC mutants) or may produce flagella that cannot rotate due to motor dysfunction (e.g., ΔmotA mutants with paralyzed flagella) (haiko2013theroleof pages 5-7, warrell2024interspeciessurfactantsservea pages 5-7, wu2020reciprocalcdigmpsignaling pages 11-13, wu2020reciprocalcdigmpsignaling pages 6-8). These represent distinct mechanistic routes.

2. **Reduced swimming speed vs. immobility:** c-di-GMP-mediated flagellar braking through YcgR-MotA/FliG interactions reduces flagellar rotation speed and alters directional bias but typically does not abolish motility entirely (han2023flagellarbrakeprotein pages 1-2, fang2010apost‐translationalc‐di‐gmp‐dependent pages 7-8). Such reduced-speed states should not be curated as constitutive non-motility.

3. **Conditional vs. constitutive non-motility:** Viscosity-dependent phenotypes (e.g., *Campylobacter jejuni* ΔvidA mutants non-motile in low viscosity but motile at high viscosity) (ribardo2024viscositydependentdeterminantsof pages 1-2, ribardo2024viscositydependentdeterminantsof pages 4-6), mechanosensing-regulated states (pathogenic *E. coli* flagellar gene suppression in liquid versus agar) (laganenka2020flagellummediatedmechanosensingand pages 4-5, laganenka2020flagellummediatedmechanosensingand pages 2-4), and developmental-stage-specific arrest (Actinoplanes zoospore rotation arrest upon nutrient sensing) (kato2024molecularmechanismof pages 5-6, kato2024molecularmechanismof pages 1-2, kato2024molecularmechanismof pages 3-4) are context-dependent and should be qualified as such.

4. **Chemotaxis defects vs. motility loss:** Mutations in chemotaxis signaling (e.g., cheA, cheB) produce altered directional responses but do not necessarily eliminate swimming motility (haiko2013theroleof pages 5-7). Chemotaxis-defective strains may migrate uniformly rather than form chemotactic rings in soft agar assays.

5. **Flagellum-dependent vs. flagellum-independent surface movement:** Exogenous surfactants can enable flagellar-dependent surface spreading on agar where cells would otherwise appear immotile (warrell2024interspeciessurfactantsservea pages 1-2, warrell2024interspeciessurfactantsservea pages 5-7). This emergent motility is distinct from passive sliding, twitching, or gliding. "Non-motile" calls from surface assays must account for the physical and chemical environment.

6. **Assay-specific interpretation:** Soft agar concentration strongly affects measured migration speed and chemotactic ring formation (croze2011migrationofchemotactic pages 5-8, croze2011migrationofchemotactic pages 1-5). Increased agar concentration suppresses chemotaxis through collision-induced perturbation of run-tumble dynamics. This represents an assay boundary condition rather than an organism-intrinsic non-motile state.

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## 2. Candidate Causal Graph Nodes Grouped by Type

### Genes and Proteins

- **FlhDC** (label-only, taxon-scoped): Master transcriptional regulator of flagellar gene expression (bacteria including *E. coli*, *Salmonella*)
- **FliC** / **FlaA** (label-only, taxon-scoped): Flagellin subunit of the flagellar filament (*Pseudomonas*, *Vibrio*, *E. coli*)
- **MotA** / **MotB** (label-only, taxon-scoped): Flagellar stator protein complex enabling proton-driven motor rotation
- **FlhF** (label-only, taxon-scoped): Signal recognition particle-type GTPase required for polar flagellar localization (*Pseudomonas aeruginosa*, *Vibrio cholerae*)
- **YcgR** (label-only, taxon-scoped): c-di-GMP-binding flagellar brake protein (*E. coli*, enterics)
- **FliG** (label-only, taxon-scoped): Switch complex and rotor component of flagellar motor
- **FliN** (label-only, taxon-scoped): C-ring component of flagellar basal body; interaction target for FtgA
- **FtgA** (label-only, *Actinoplanes missouriensis* specific): Protein mediating flagellar rotation arrest during zoospore germination
- **CheA1**, **CheW1-2** (label-only, *Actinoplanes* chemotaxis cluster-1): Chemotaxis signaling proteins forming the sensory complex that modulates FtgA availability
- **VidA**, **VidB** (label-only, *Campylobacter jejuni* specific): Viscosity-dependent determinants regulating swimming velocity across viscosity gradients
- **HsbR**, **WspR** (label-only, *Pseudomonas* specific): Response regulators in c-di-GMP signaling linked to FlhF-mediated biofilm/motility regulation

### Biological Processes and Molecular Functions

- **Bacterial-type flagellum-dependent cell motility** (GO:0071973): The process enabling active self-propelled movement driven by flagellar rotation
- **Bacterial-type flagellum** (GO:0009288): The flagellar apparatus including basal body, hook, and filament
- **c-di-GMP binding** (GO:0035438): Molecular function enabling YcgR and other proteins to respond to elevated cyclic di-GMP
- **Chemotaxis** (GO:0006935): Directed movement along chemical gradients; chemotaxis defects may confound non-motile interpretation in certain assays
- **Biofilm formation** (GO:0042710): Sessile community phenotype often reciprocally regulated with motility

### Chemicals and Metabolites

- **Cyclic di-GMP** (CHEBI:49537): Second messenger controlling motility-sessility transitions through binding to effectors such as YcgR

### Environmental and Assay Factors

- **Soft agar concentration** (label-only): Gel network density (typically 0.15–0.5% w/v) influencing bacterial motility assays through collision-induced run-tumble perturbation
- **Viscosity** (label-only, quantified in cP in source): Environmental medium viscosity affecting swimming speed and flagellar motor output
- **Exogenous surfactants** (label-only): Secreted molecules (bacterial rhamnolipids, PSMs, plant saponins, host mucin, synthetic SDS) enabling flagellar-based surface spreading where cells are otherwise immotile on agar
- **Nutrient signal** (label-only, *Actinoplanes*-specific): Environmental cue triggering zoospore swimming cessation and germination initiation

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Showing the first 60 of 259 lines of findings; the linked file also carries the run's front matter and the prompt it was given — read the full report.