identifier: traitmech:000464
label: DS-42 system
definition: A phage defense system in which an organism possesses the three-gene DefensePredictor-discovered
  system 42 locus cataloged as working transcriptional unit PRO1 and whose plasmid
  expression in E. coli MG1655 reduced bacteriophage plaquing.
definition_source: DOI:10.1126/science.adv7924
trait_category: GENOMICS
term_kind: CLASS
mapping_status: PROPOSED
parent_traits:
- traitmech:000209
synonyms:
- synonym_text: DS-42
  synonym_type: EXACT_SYNONYM
  source: DOI:10.1126/science.adv7924
- synonym_text: PRO1
  synonym_type: RELATED_SYNONYM
  source: https://pmc-oa-opendata.s3.amazonaws.com/PMC13092281.1/NIHMS2163519-supplement-Table_S6.xlsx
- synonym_text: DS-42__DS-42A
  synonym_type: RELATED_SYNONYM
  source: https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/Liste_hmm_system.md
- synonym_text: DS-42__DS-42B
  synonym_type: RELATED_SYNONYM
  source: https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/Liste_hmm_system.md
- synonym_text: DS-42__DS-42C
  synonym_type: RELATED_SYNONYM
  source: https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/Liste_hmm_system.md
evidence:
- reference: DOI:10.1126/science.adv7924
  snippet: To test for anti-phage defense, we placed each TU with its predicted native
    promoter region on a low-copy number plasmid in E. coli MG1655 and challenged
    these strains with a panel of 24 diverse E. coli phages (Fig. 3; fig. S2). In
    total, 42 (45% of 94) of the cloned TUs produced smaller plaque sizes or reduced
    the efficiency of plating (EOP) at least ten-fold relative to an empty vector
    control strain
  notes: DeWeirdt et al. experimentally validated 42 predicted transcriptional units
    as phage-defense systems in E. coli.
- reference: DOI:10.1126/science.adv7924
  snippet: We refer to these validated TUs as DefensePredictor discovered systems
    (DSs), with genes in multi-gene TUs denoted by an alphabetical suffix, e.g., DS-8A
    is the first gene of DS-8.
  notes: DeWeirdt et al. name validated transcriptional units as DefensePredictor
    discovered systems.
- reference: https://pmc-oa-opendata.s3.amazonaws.com/PMC13092281.1/NIHMS2163519-supplement-Table_S6.xlsx
  snippet: "PRO1\tNZ_QOXO01000016.1\tGCF_003334005.1\t-\tTrue\tFalse\tTrue\tTrue\t\
    DefensePredictor hits\t661\t3061\tMBL fold metallo-hydrolase, hypothetical protein,\
    \ hypothetical protein\tWP_001198055.1, WP_001024069.1, WP_249925928.1\t4.870544869418898\t\
    6.906754778648663\tTrue\tTrue\tPredicted novel defense gene\tDS-42"
  notes: The final Science supplementary Table S6 maps working_id PRO1 to DS_name
    DS-42, marks the cloned transcriptional unit as defensive, and records NZ_QOXO01000016.1
    positions 661-3061 with product accessions WP_001198055.1, WP_001024069.1, and
    WP_249925928.1.
- reference: https://pmc-oa-opendata.s3.amazonaws.com/PMC13092281.1/NIHMS2163519-supplement-Table_S7.xlsx
  snippet: "Bas1\t3.1\tpLAND\t24-04-10_CITO_AAA3_FDRT_EV.png\t5000000\tPRO1\t24-04-13\t\
    24-04-13_PRO1_CBT2_AAA4_TMRA.png\t5\t4\tY\t400000\t1.0969100130080565\t\tTrue\t\
    \tLB\t37"
  notes: The final Science supplementary Table S7 Systems sheet reports a PRO1 assay
    row with a Bas1 phage readout and a -log(EOP) value of 1.097.
- reference: https://pmc-oa-opendata.s3.amazonaws.com/PMC13092281.1/NIHMS2163519-supplement-Table_S8.xlsx
  snippet: "PRO1\tDS-42\tTrue"
  notes: The final Science supplementary Table S8 maps PRO1 to replicated display
    name DS-42.
- reference: https://pmc-oa-opendata.s3.amazonaws.com/PMC13092281.1/NIHMS2163519-supplement-Table_S8.xlsx
  snippet: "PRO1\t3.0\t363.0\tWP_001198055.1\tMBL hydrolase\tcd07731\tComA-like_MBL-fold;\
    \ Competence protein ComA, ComEC and related proteins\thhpred_9048500.hhr\t12.0\t\
    251.0\t0.998\t2024-04-15 00:00:00\t\t"
  notes: The final Science supplementary Table S8 reports a high-probability MBL hydrolase
    HHpred hit for WP_001198055.1 in PRO1.
- reference: https://pmc-oa-opendata.s3.amazonaws.com/PMC13092281.1/NIHMS2163519-supplement-Table_S8.xlsx
  snippet: "PRO1\t2.0\t190.0\tWP_001024069.1\tDimerization\tPF16892.9\tCHS5_N ; Chitin\
    \ biosynthesis protein CHS5 N-terminus\thhpred_3514574.hhr\t108.0\t166.0\t0.7787\t\
    2024-04-15 00:00:00\t\t"
  notes: The final Science supplementary Table S8 reports a moderate-probability CHS5_N/Dimerization
    HHpred hit for WP_001024069.1 in PRO1.
- reference: https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/List_system_article.md
  snippet: '| DS-42 | 10\.1101/2025\.01\.08\.631726 | DefensePredictor: A machine
    learning model to discover novel prokaryotic immune systems | '
  notes: The pinned DefenseFinder article registry maps the DS-42 source key to the
    preprint DOI for the DeWeirdt et al. DefensePredictor study, which has since been
    published in Science.
- reference: https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/Liste_hmm_system.md
  snippet: '| DS-42__DS-42A                                    |                                                  |
    DS-42                  | Custom                  | 70     |'
  notes: The pinned DefenseFinder HMM inventory records DS-42__DS-42A as a custom
    DS-42 profile.
- reference: https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/Liste_hmm_system.md
  snippet: '| DS-42__DS-42B                                    |                                                  |
    DS-42                  | Custom                  | 20     |'
  notes: The pinned DefenseFinder HMM inventory records DS-42__DS-42B as a custom
    DS-42 profile.
- reference: https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/Liste_hmm_system.md
  snippet: '| DS-42__DS-42C                                    |                                                  |
    DS-42                  | Custom                  | 200    |'
  notes: The pinned DefenseFinder HMM inventory records DS-42__DS-42C as a custom
    DS-42 profile.
causal_graphs:
- graph_id: ds_42_locus_reduces_phage_plaquing
  title: DS-42 locus reduces bacteriophage plaquing
  description: Conservative system-level sketch linking the three-gene DS-42 locus
    to reduced bacteriophage plaquing without resolving DS-42 component function or
    molecular output.
  scope_status: NONMECHANISTIC
  scope_notes: The graph captures DS-42 as the validated PRO1 transcriptional unit
    with three product accessions, a high-probability MBL hydrolase HHpred row for
    WP_001198055.1, a moderate-probability CHS5_N/Dimerization HHpred row for WP_001024069.1,
    and three DefenseFinder DS-42 profile rows. It does not assert native host breadth,
    exact profile-to-protein correspondence, MBL hydrolase or CHS5_N interpretation,
    WP_249925928.1 function, DS-42 molecular activity, complete phage breadth, or
    DefenseFinder rule-level detection criteria.
  nodes:
  - node_id: ds_42_locus
    label: DS-42 locus
    node_type: GENETIC_ELEMENT
    description: A three-gene DefensePredictor-discovered system 42 locus represented
      in the pinned DefenseFinder HMM inventory by three DS-42 custom profiles.
  - node_id: reduced_phage_plaquing
    label: reduced bacteriophage plaquing
    node_type: BIOLOGICAL_PROCESS
    description: Reduced bacteriophage plaquing in cells carrying cloned PRO1.
  - node_id: ds_42_system_trait
    label: DS-42 system
    node_type: TRAIT
    grounding: traitmech:000464
    description: Possession of a genome-encoded DS-42 phage-defense system.
  - node_id: phage_defense_system
    label: phage defense system
    node_type: TRAIT
    grounding: traitmech:000209
    description: Possession of one or more genome-encoded immune systems that inhibit
      bacteriophage infection.
  edges:
  - subject: ds_42_locus
    predicate: contributes to
    predicate_id: RO:0002326
    object: reduced_phage_plaquing
    description: The DS-42/PRO1 locus contributes to reduced bacteriophage plaquing
      in heterologous E. coli MG1655 plasmid-expression assays.
    evidence:
    - reference: DOI:10.1126/science.adv7924
      snippet: To test for anti-phage defense, we placed each TU with its predicted
        native promoter region on a low-copy number plasmid in E. coli MG1655 and
        challenged these strains with a panel of 24 diverse E. coli phages (Fig. 3;
        fig. S2). In total, 42 (45% of 94) of the cloned TUs produced smaller plaque
        sizes or reduced the efficiency of plating (EOP) at least ten-fold relative
        to an empty vector control strain
      notes: DeWeirdt et al. describe the plasmid-based phage challenge used to validate
        predicted transcriptional units.
    - reference: https://pmc-oa-opendata.s3.amazonaws.com/PMC13092281.1/NIHMS2163519-supplement-Table_S6.xlsx
      snippet: "PRO1\tNZ_QOXO01000016.1\tGCF_003334005.1\t-\tTrue\tFalse\tTrue\tTrue\t\
        DefensePredictor hits\t661\t3061\tMBL fold metallo-hydrolase, hypothetical\
        \ protein, hypothetical protein\tWP_001198055.1, WP_001024069.1, WP_249925928.1\t\
        4.870544869418898\t6.906754778648663\tTrue\tTrue\tPredicted novel defense\
        \ gene\tDS-42"
      notes: The final Science supplementary Table S6 maps working_id PRO1 to DS_name
        DS-42, marks the cloned transcriptional unit as defensive, and records NZ_QOXO01000016.1
        positions 661-3061 with product accessions WP_001198055.1, WP_001024069.1,
        and WP_249925928.1.
    - reference: https://pmc-oa-opendata.s3.amazonaws.com/PMC13092281.1/NIHMS2163519-supplement-Table_S7.xlsx
      snippet: "Bas1\t3.1\tpLAND\t24-04-10_CITO_AAA3_FDRT_EV.png\t5000000\tPRO1\t\
        24-04-13\t24-04-13_PRO1_CBT2_AAA4_TMRA.png\t5\t4\tY\t400000\t1.0969100130080565\t\
        \tTrue\t\tLB\t37"
      notes: The final Science supplementary Table S7 Systems sheet reports a PRO1
        assay row with a Bas1 phage readout and a -log(EOP) value of 1.097.
    - reference: https://pmc-oa-opendata.s3.amazonaws.com/PMC13092281.1/NIHMS2163519-supplement-Table_S8.xlsx
      snippet: "PRO1\tDS-42\tTrue"
      notes: The final Science supplementary Table S8 maps PRO1 to replicated display
        name DS-42.
    - reference: https://pmc-oa-opendata.s3.amazonaws.com/PMC13092281.1/NIHMS2163519-supplement-Table_S8.xlsx
      snippet: "PRO1\t3.0\t363.0\tWP_001198055.1\tMBL hydrolase\tcd07731\tComA-like_MBL-fold;\
        \ Competence protein ComA, ComEC and related proteins\thhpred_9048500.hhr\t\
        12.0\t251.0\t0.998\t2024-04-15 00:00:00\t\t"
      notes: The final Science supplementary Table S8 reports a high-probability MBL
        hydrolase HHpred hit for WP_001198055.1 in PRO1.
    - reference: https://pmc-oa-opendata.s3.amazonaws.com/PMC13092281.1/NIHMS2163519-supplement-Table_S8.xlsx
      snippet: "PRO1\t2.0\t190.0\tWP_001024069.1\tDimerization\tPF16892.9\tCHS5_N\
        \ ; Chitin biosynthesis protein CHS5 N-terminus\thhpred_3514574.hhr\t108.0\t\
        166.0\t0.7787\t2024-04-15 00:00:00\t\t"
      notes: The final Science supplementary Table S8 reports a moderate-probability
        CHS5_N/Dimerization HHpred hit for WP_001024069.1 in PRO1.
    - reference: https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/Liste_hmm_system.md
      snippet: '| DS-42__DS-42A                                    |                                                  |
        DS-42                  | Custom                  | 70     |'
      notes: The pinned DefenseFinder HMM inventory records DS-42__DS-42A as a custom
        DS-42 profile.
    - reference: https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/Liste_hmm_system.md
      snippet: '| DS-42__DS-42B                                    |                                                  |
        DS-42                  | Custom                  | 20     |'
      notes: The pinned DefenseFinder HMM inventory records DS-42__DS-42B as a custom
        DS-42 profile.
    - reference: https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/Liste_hmm_system.md
      snippet: '| DS-42__DS-42C                                    |                                                  |
        DS-42                  | Custom                  | 200    |'
      notes: The pinned DefenseFinder HMM inventory records DS-42__DS-42C as a custom
        DS-42 profile.
  - subject: reduced_phage_plaquing
    predicate: confers
    predicate_id: METPO:2007700
    object: ds_42_system_trait
    description: DS-42-mediated phage plaquing reduction realizes the DS-42 system
      trait.
    evidence:
    - reference: https://pmc-oa-opendata.s3.amazonaws.com/PMC13092281.1/NIHMS2163519-supplement-Table_S6.xlsx
      snippet: "PRO1\tNZ_QOXO01000016.1\tGCF_003334005.1\t-\tTrue\tFalse\tTrue\tTrue\t\
        DefensePredictor hits\t661\t3061\tMBL fold metallo-hydrolase, hypothetical\
        \ protein, hypothetical protein\tWP_001198055.1, WP_001024069.1, WP_249925928.1\t\
        4.870544869418898\t6.906754778648663\tTrue\tTrue\tPredicted novel defense\
        \ gene\tDS-42"
      notes: The final Science supplementary Table S6 maps working_id PRO1 to DS_name
        DS-42, marks the cloned transcriptional unit as defensive, and records NZ_QOXO01000016.1
        positions 661-3061 with product accessions WP_001198055.1, WP_001024069.1,
        and WP_249925928.1.
    - reference: https://pmc-oa-opendata.s3.amazonaws.com/PMC13092281.1/NIHMS2163519-supplement-Table_S7.xlsx
      snippet: "Bas1\t3.1\tpLAND\t24-04-10_CITO_AAA3_FDRT_EV.png\t5000000\tPRO1\t\
        24-04-13\t24-04-13_PRO1_CBT2_AAA4_TMRA.png\t5\t4\tY\t400000\t1.0969100130080565\t\
        \tTrue\t\tLB\t37"
      notes: The final Science supplementary Table S7 Systems sheet reports a PRO1
        assay row with a Bas1 phage readout and a -log(EOP) value of 1.097.
    - reference: DOI:10.1126/science.adv7924
      snippet: We refer to these validated TUs as DefensePredictor discovered systems
        (DSs), with genes in multi-gene TUs denoted by an alphabetical suffix, e.g.,
        DS-8A is the first gene of DS-8.
      notes: The DS nomenclature is used for DefensePredictor discovered systems.
  - subject: ds_42_system_trait
    predicate: is a
    predicate_id: rdfs:subClassOf
    object: phage_defense_system
    description: DS-42 system possession is a phage-defense-system trait.
    evidence:
    - reference: DOI:10.1126/science.adv7924
      snippet: We refer to these validated TUs as DefensePredictor discovered systems
        (DSs), with genes in multi-gene TUs denoted by an alphabetical suffix, e.g.,
        DS-8A is the first gene of DS-8.
      notes: DeWeirdt et al. name validated TUs as DefensePredictor discovered systems.
    - reference: https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/List_system_article.md
      snippet: '| DS-42 | 10\.1101/2025\.01\.08\.631726 | DefensePredictor: A machine
        learning model to discover novel prokaryotic immune systems | '
      notes: The pinned DefenseFinder article registry maps the DS-42 source key to
        the preprint DOI for the DeWeirdt et al. DefensePredictor study, which has
        since been published in Science.
discussions:
- discussion_id: ds-42-defensefinder-model-gap
  prompt: Resolve DS-42 native host breadth, exact component activity, profile-to-protein
    mapping, MBL hydrolase and CHS5_N interpretations, WP_249925928.1 function, complete
    phage breadth, molecular output, and rule-level DefenseFinder criteria before
    minting narrower DS-42 mechanism children.
  kind: KNOWLEDGE_GAP
  status: OPEN
  rationale: DeWeirdt et al. support DS-42 as the defensive PRO1 transcriptional unit
    and final Science Tables S6/S7/S8 map it to three product accessions, a Bas1 phage
    readout, display name DS-42, a high-probability MBL hydrolase HHpred row, and
    a moderate-probability CHS5_N/Dimerization HHpred row. The pinned DefenseFinder
    HMM inventory records three DS-42 custom profile rows. The pinned rules table
    has no DS-42 row, and the first-pass record does not resolve native host breadth,
    complete phage breadth, direct profile-to-protein correspondence, component activities,
    molecular output, or endogenous DS-42 activity.
  evidence:
  - reference: DOI:10.1126/science.adv7924
    snippet: We refer to these validated TUs as DefensePredictor discovered systems
      (DSs), with genes in multi-gene TUs denoted by an alphabetical suffix, e.g.,
      DS-8A is the first gene of DS-8.
    notes: DeWeirdt et al. name validated TUs as DSs.
  - reference: https://pmc-oa-opendata.s3.amazonaws.com/PMC13092281.1/NIHMS2163519-supplement-Table_S6.xlsx
    snippet: "PRO1\tNZ_QOXO01000016.1\tGCF_003334005.1\t-\tTrue\tFalse\tTrue\tTrue\t\
      DefensePredictor hits\t661\t3061\tMBL fold metallo-hydrolase, hypothetical protein,\
      \ hypothetical protein\tWP_001198055.1, WP_001024069.1, WP_249925928.1\t4.870544869418898\t\
      6.906754778648663\tTrue\tTrue\tPredicted novel defense gene\tDS-42"
    notes: The final Science supplementary Table S6 maps working_id PRO1 to DS_name
      DS-42, marks the cloned transcriptional unit as defensive, and records NZ_QOXO01000016.1
      positions 661-3061 with product accessions WP_001198055.1, WP_001024069.1, and
      WP_249925928.1.
  - reference: https://pmc-oa-opendata.s3.amazonaws.com/PMC13092281.1/NIHMS2163519-supplement-Table_S7.xlsx
    snippet: "Bas1\t3.1\tpLAND\t24-04-10_CITO_AAA3_FDRT_EV.png\t5000000\tPRO1\t24-04-13\t\
      24-04-13_PRO1_CBT2_AAA4_TMRA.png\t5\t4\tY\t400000\t1.0969100130080565\t\tTrue\t\
      \tLB\t37"
    notes: The final Science supplementary Table S7 Systems sheet reports a PRO1 assay
      row with a Bas1 phage readout and a -log(EOP) value of 1.097.
  - reference: https://pmc-oa-opendata.s3.amazonaws.com/PMC13092281.1/NIHMS2163519-supplement-Table_S8.xlsx
    snippet: "PRO1\tDS-42\tTrue"
    notes: The final Science supplementary Table S8 maps PRO1 to replicated display
      name DS-42.
  - reference: https://pmc-oa-opendata.s3.amazonaws.com/PMC13092281.1/NIHMS2163519-supplement-Table_S8.xlsx
    snippet: "PRO1\t3.0\t363.0\tWP_001198055.1\tMBL hydrolase\tcd07731\tComA-like_MBL-fold;\
      \ Competence protein ComA, ComEC and related proteins\thhpred_9048500.hhr\t\
      12.0\t251.0\t0.998\t2024-04-15 00:00:00\t\t"
    notes: The final Science supplementary Table S8 reports a high-probability MBL
      hydrolase HHpred hit for WP_001198055.1 in PRO1.
  - reference: https://pmc-oa-opendata.s3.amazonaws.com/PMC13092281.1/NIHMS2163519-supplement-Table_S8.xlsx
    snippet: "PRO1\t2.0\t190.0\tWP_001024069.1\tDimerization\tPF16892.9\tCHS5_N ;\
      \ Chitin biosynthesis protein CHS5 N-terminus\thhpred_3514574.hhr\t108.0\t166.0\t\
      0.7787\t2024-04-15 00:00:00\t\t"
    notes: The final Science supplementary Table S8 reports a moderate-probability
      CHS5_N/Dimerization HHpred hit for WP_001024069.1 in PRO1.
  - reference: https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/List_system_article.md
    snippet: '| DS-42 | 10\.1101/2025\.01\.08\.631726 | DefensePredictor: A machine
      learning model to discover novel prokaryotic immune systems | '
    notes: The pinned DefenseFinder article registry maps the DS-42 source key to
      the preprint DOI for the DeWeirdt et al. DefensePredictor study, which has since
      been published in Science.
  - reference: https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/Liste_hmm_system.md
    snippet: '| DS-42__DS-42A                                    |                                                  |
      DS-42                  | Custom                  | 70     |'
    notes: The pinned DefenseFinder HMM inventory records DS-42__DS-42A as a custom
      DS-42 profile.
  - reference: https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/Liste_hmm_system.md
    snippet: '| DS-42__DS-42B                                    |                                                  |
      DS-42                  | Custom                  | 20     |'
    notes: The pinned DefenseFinder HMM inventory records DS-42__DS-42B as a custom
      DS-42 profile.
  - reference: https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/Liste_hmm_system.md
    snippet: '| DS-42__DS-42C                                    |                                                  |
      DS-42                  | Custom                  | 200    |'
    notes: The pinned DefenseFinder HMM inventory records DS-42__DS-42C as a custom
      DS-42 profile.
  - reference: https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/DefenseFinder_rules.tsv
    notes: The pinned DefenseFinder rules table does not list DS-42, leaving rule-level
      detection criteria unresolved.
  attaches_to:
  - causal_graphs#ds_42_locus_reduces_phage_plaquing
  posed_by: codex
  posed_date: '2026-09-29'
curation_history:
- timestamp: '2026-09-29T13:30:52Z'
  curator: codex
  action: MINTED_TRAITMECH_ID
  changes: Minted DS-42 system as a DOI-backed GENOMICS TraitRecord under phage defense
    system after an ignored-and-hidden duplicate review found no exact live TraitMech,
    METPO, history, or prior proposal record; kept the graph at PRO1 transcriptional-unit
    level because component activities and rule rows remain unresolved, and proposals/metpo_traitmech_v341
    reserves the replacement placeholder.
  llm_assisted: true
- timestamp: '2026-09-29T13:30:53Z'
  curator: codex
  action: REVIEW_CANONICAL_EXAMPLE_EVIDENCE_GAP
  changes: Reviewed DS-42 system canonical_examples and left them empty because DeWeirdt
    et al. directly support cloned PRO1 assays in E. coli MG1655 and a DefenseFinder
    DS-42 model, but not a direct named native microbial isolate exemplar with experimentally
    verified endogenous DS-42 activity. No paid research was used.
  llm_assisted: true