identifier: traitmech:000017
label: arsenic tolerant
definition: A metalloid tolerance in which an organism grows in the presence of elevated
  arsenic (arsenite/arsenate) concentrations, typically via the ars operon, whose
  ArsB pump extrudes arsenite from the cytoplasm.
definition_source: DOI:10.3389/fmicb.2018.02473
trait_category: ENVIRONMENT
term_kind: CLASS
mapping_status: REVIEWED
parent_traits:
- traitmech:000012
synonyms:
- synonym_text: arsenic resistant
  synonym_type: RELATED_SYNONYM
  source: DOI:10.3389/fmicb.2018.02473
evidence:
- reference: DOI:10.3389/fmicb.2018.02473
  snippet: ArsB is an integral membrane protein able to extrude arsenite from the
    cell cytoplasm, thus diminishing arsenite accumulation
  notes: Review supports the ars operon as a near-ubiquitous arsenic-resistance determinant,
    "more common than genes for tryptophan biosynthesis".
- reference: DOI:10.3389/fmicb.2020.00047
  snippet: C. metallidurans BS1 conferred resistance to Zn2+ displaying a MIC of 20
    mM, Cd2+ (2.5 mM), Co2+ (20mM), Ni2+ (8 mM), As3+ (3.5 mM), Cu2+ (5 mM), Au3+
    (1 uM) and Pb2+ (1.7 mM)
  notes: 'Organism example: Cupriavidus metallidurans BS1 tolerates arsenite (As3+)
    to a MIC of 3.5 mM.'
canonical_examples:
- taxon_id: NCBITaxon:119219
  taxon_label: Cupriavidus metallidurans
  note: "broad heavy-metal/metalloid resistance"
  reference: PMID:20463976
- taxon_id: NCBITaxon:303
  taxon_label: Pseudomonas putida
  note: "metal-tolerant soil bacterium"
  reference: PMID:25646541
causal_graphs:
- graph_id: arsenic_tolerance_ars_efflux
  title: Arsenic tolerance via ars-operon arsenite efflux
  description: Evidence-backed causal sketch linking the ars operon and ArsB pump
    to extrusion of cytoplasmic arsenite.
  nodes:
  - node_id: arsenic_tolerant_trait
    label: arsenic tolerant
    node_type: TRAIT
    grounding: traitmech:000017
    description: Capacity to grow at elevated arsenite/arsenate concentrations.
  - node_id: arsenite
    label: arsenite(3-)
    node_type: CHEMICAL
    grounding: CHEBI:29242
    description: Toxic trivalent arsenic species accumulating in the cytoplasm.
  - node_id: ars_operon
    label: ars operon (ArsB pump)
    node_type: GENE_OR_PROTEIN
    description: Arsenite efflux machinery encoded by the near-ubiquitous ars operon.
  - node_id: arsenite_export
    label: arsenite transmembrane transport
    node_type: BIOLOGICAL_PROCESS
    grounding: GO:0030001
    description: Active export of arsenite across the cytoplasmic membrane.
  - node_id: arsenate
    label: arsenate(3-)
    node_type: CHEMICAL
    description: Pentavalent arsenic species; substrate for arsenate reductase.
    grounding: CHEBI:29125
  - node_id: arsR_repressor
    label: ArsR transcriptional repressor
    node_type: GENE_OR_PROTEIN
    description: Trans-acting repressor that binds the ars promoter and de-represses
      upon arsenite binding.
  - node_id: ars_promoter
    label: ars promoter
    node_type: GENE_OR_PROTEIN
    description: Promoter controlling transcription of the ars operon.
  - node_id: arsC_reductase
    label: ArsC arsenate reductase
    node_type: GENE_OR_PROTEIN
    description: Cytoplasmic arsenate reductase converting As(V) to As(III).
  - node_id: arsenate_reduction
    label: arsenate reduction to arsenite
    node_type: BIOLOGICAL_PROCESS
    description: Reduction of intracellular arsenate to arsenite prior to efflux.
  - node_id: arsB_pump
    label: ArsB arsenite efflux permease
    node_type: GENE_OR_PROTEIN
    description: Integral membrane arsenite efflux pump extruding As(III) from the
      cytoplasm.
  - node_id: acr3_pump
    label: Acr3 arsenite efflux permease
    node_type: GENE_OR_PROTEIN
    description: Alternative inorganic arsenite efflux pump exporting As(III).
  - node_id: arsM_methyltransferase
    label: ArsM arsenite S-adenosylmethionine methyltransferase
    node_type: GENE_OR_PROTEIN
    description: Enzyme methylating arsenite to volatile methylated arsenicals.
  - node_id: arsenite_methylation
    label: arsenite methylation
    node_type: BIOLOGICAL_PROCESS
    description: Methylation of arsenite producing volatile methylated arsenic, a
      detoxification route.
  edges:
  - subject: arsenite
    predicate: challenges
    object: arsenic_tolerant_trait
    description: Cytoplasmic arsenite is the toxic challenge the trait counters.
    evidence:
    - reference: DOI:10.3389/fmicb.2020.00047
      notes: Cupriavidus metallidurans BS1 tolerates arsenite to a MIC of 3.5 mM.
    predicate_id: METPO:2007406
  - subject: ars_operon
    predicate: enables
    object: arsenite_export
    description: ArsB pumps arsenite out of the cytoplasm.
    evidence:
    - reference: DOI:10.3389/fmicb.2018.02473
      notes: ArsB is an integral membrane protein extruding arsenite from the cell
        cytoplasm.
    predicate_id: RO:0002327
  - subject: arsenite_export
    predicate: mitigates
    object: arsenite
    description: Active export depletes the cytoplasmic arsenite pool.
    evidence:
    - reference: DOI:10.3389/fmicb.2018.02473
      notes: The ars operon is the near-ubiquitous arsenic-resistance determinant.
    predicate_id: METPO:2007407
  - subject: arsR_repressor
    predicate: represses
    object: ars_promoter
    description: ArsR represses ars-operon transcription in the absence of arsenite.
    evidence:
    - reference: DOI:10.3390/antibiotics12091474
      notes: ArsR is a trans-acting transcriptional repressor that binds the ars promoter.
  - subject: arsenite
    predicate: relieves repression by
    object: arsR_repressor
    description: Arsenite binding changes ArsR conformation and de-represses ars transcription.
    evidence:
    - reference: DOI:10.3389/fmicb.2024.1494872
      notes: Binding of As(III) to ArsR changes its conformation and relieves repression
        of the ars operon.
  - subject: arsC_reductase
    predicate: enables
    object: arsenate_reduction
    description: ArsC reduces intracellular arsenate to arsenite.
    evidence:
    - reference: DOI:10.3390/antibiotics12091474
      notes: ArsC is an arsenate reductase that converts intracellular As(V) to As(III).
    predicate_id: RO:0002327
  - subject: arsenate_reduction
    predicate: produces
    object: arsenite
    description: Arsenate reduction yields arsenite, the substrate for efflux.
    evidence:
    - reference: DOI:10.3390/antibiotics12091474
      notes: ArsC converts intracellular As(V) to As(III), feeding the efflux route.
    predicate_id: METPO:2000202
  - subject: arsB_pump
    predicate: enables
    object: arsenite_export
    description: ArsB is an integral membrane pump extruding arsenite from the cytoplasm.
    evidence:
    - reference: DOI:10.3390/antibiotics12091474
      notes: ArsB is an integral membrane arsenite efflux pump that extrudes As(OH)3/As3+
        from the cytoplasm.
    predicate_id: RO:0002327
  - subject: acr3_pump
    predicate: enables
    object: arsenite_export
    description: Acr3 is an alternative inorganic arsenite efflux pump.
    evidence:
    - reference: DOI:10.3390/microorganisms12010074
      notes: Some bacteria possess acr3, coding for an inorganic arsenite efflux pump.
    predicate_id: RO:0002327
  - subject: arsM_methyltransferase
    predicate: enables
    object: arsenite_methylation
    description: ArsM methylates arsenite to volatile methylated arsenicals.
    evidence:
    - reference: DOI:10.7717/peerj.18383
      notes: arsM (arsenite S-adenosylmethionine methyltransferase) produces volatile
        methylated arsenicals.
    predicate_id: RO:0002327
  - subject: arsenite_methylation
    predicate: mitigates
    object: arsenite
    description: Methylation and volatilization depletes the cytoplasmic arsenite
      pool, a detoxification route.
    evidence:
    - reference: DOI:10.7717/peerj.18383
      notes: Produced arsenite is methylated by arsM to volatile methylated arsenic,
        removing it from the cell.
    predicate_id: METPO:2007407
  - subject: arsC_reductase
    predicate: reduces
    object: arsenate
    description: Arsenate reductase reduces arsenate to arsenite, the form handled
      by efflux pumps.
    evidence:
    - reference: DOI:10.3389/fmicb.2020.00047
      notes: Connecting edge wiring the enrichment node into the graph.
    predicate_id: METPO:2000017
curation_history:
- timestamp: '2026-05-28T00:00:00Z'
  curator: claude
  action: PROPOSED_FROM_RESEARCH
  changes: Proposed candidate ENVIRONMENT trait (arsenic/metalloid tolerance) from
    literature research; sub-variant of metal tolerant.
  llm_assisted: true
- timestamp: '2026-06-09T14:00:00Z'
  curator: claude
  action: CURATED_CAUSAL_GRAPH
  changes: Added evidence-backed causal graph (ars-operon arsenite efflux) with CHEBI/GO
    node groundings and RO/METPO predicate groundings; promoted PROPOSED to REVIEWED.
  llm_assisted: true
- timestamp: '2026-06-23T00:00:00Z'
  curator: claude
  action: ENRICH_CAUSAL_GRAPH
  changes: Added 8 evidence-backed generic edges (9 new nodes) from the deep-research
    report.
  llm_assisted: true
- timestamp: '2026-06-23T00:00:00Z'
  curator: claude
  action: FIX_ORPHAN_NODE
  changes: Connected orphaned node 'arsenate' via arsC_reductase -[reduces]-> arsenate.
  llm_assisted: true
- timestamp: '2026-06-24T17:21:09Z'
  curator: claude
  action: GROUND_CAUSAL_PREDICATES
  changes: Grounded 7 causal-edge predicate_id field(s) via mappings/predicate_grounding.tsv
    (RO:0002327×4, METPO:2000202×1, METPO:2007407×1, METPO:2000017×1).
  llm_assisted: true
- timestamp: '2026-06-24T17:23:30Z'
  curator: claude
  action: GROUND_CAUSAL_NODES
  changes: Grounded 1 causal-node grounding field(s) via mappings/node_grounding.tsv
    (CHEBI:29125×1).
  llm_assisted: true