identifier: METPO:1000466 label: NaCl optimum mid1 definition: A NaCl optimum phenotype with the best-growth NaCl concentration approximately between 1 and 3% (w/v), corresponding to slight-halophile or halotolerant physiology. definition_source: DOI:10.1093/femsre/fuy009 trait_category: ENVIRONMENT term_kind: CLASS mapping_status: REVIEWED parent_traits: - METPO:1000333 synonyms: - synonym_text: Halotolerant synonym_type: EXACT_SYNONYM source: metpo.owl - synonym_text: Slight halophile synonym_type: EXACT_SYNONYM source: metpo.owl - synonym_text: NaO_1_to_3 synonym_type: RELATED_SYNONYM source: metpo.owl evidence: - reference: DOI:10.1093/femsre/fuy009 snippet: slight halophile notes: Osmoadaptation review supports the 1–3% NaCl optimum range as the slight-halophile category. causal_graphs: - graph_id: nacl_optimum_mid1_slight_halophile title: NaCl-optimum-mid1 slight-halophile setpoint description: DOI-backed graph linking modest osmoadaptive activity at seawater-like NaCl to a 1–3% (w/v) NaCl-optimum (slight halophile). nodes: - node_id: nacl_optimum_mid1_trait label: NaCl optimum mid1 node_type: TRAIT grounding: METPO:1000466 description: NaCl optimum approximately 1–3% w/v. - node_id: nacl_optimum label: NaCl optimum node_type: TRAIT grounding: METPO:1000333 description: NaCl concentration supporting maximal growth. - node_id: seawater_nacl label: seawater-like NaCl node_type: ENVIRONMENTAL_FACTOR description: Marine or estuarine external NaCl ~1–3% w/v. - node_id: modest_osmoadaptation label: modest osmoadaptation node_type: BIOLOGICAL_PROCESS description: Compatible-solute accumulation and ion homeostasis tuned for seawater-range NaCl. - node_id: slight_halophile_physiology label: slight halophile / halotolerant physiology node_type: STATE description: Physiology of microbes with best growth at ~1-3% NaCl. - node_id: salt_in_strategy label: salt-in osmoregulation strategy node_type: BIOLOGICAL_PROCESS description: Accumulation of inorganic ions (notably K+) and exclusion of Na+ to balance external salinity. - node_id: compatible_solute_strategy label: compatible-solute osmoregulation strategy node_type: BIOLOGICAL_PROCESS description: Biosynthesis or uptake of small organic osmolytes (salt-out strategy) to offset osmotic stress. - node_id: elevated_nacl label: elevated external NaCl node_type: ENVIRONMENTAL_FACTOR description: Increased external NaCl concentration imposing osmotic stress. - node_id: glycine_betaine label: glycine betaine node_type: CHEMICAL description: Compatible solute (CHEBI:17750) accumulated under osmotic stress. grounding: CHEBI:17750 - node_id: l_proline label: L-proline node_type: CHEMICAL description: Compatible solute (CHEBI:17203) accumulated under osmotic stress. edges: - subject: seawater_nacl predicate: engages object: modest_osmoadaptation description: Seawater-like NaCl engages a moderate osmoadaptive program. evidence: - reference: DOI:10.1093/femsre/fuy009 snippet: slight halophile notes: Supports seawater-range NaCl as the context for slight-halophile optima. - subject: modest_osmoadaptation predicate: produces object: nacl_optimum_mid1_trait description: A modest osmoadaptive program yields a 1–3% NaCl-optimum setpoint. evidence: - reference: DOI:10.1093/femsre/fuy009 snippet: slight halophile notes: Supports the 1–3% optimum as the slight-halophile outcome. predicate_id: METPO:2000202 - subject: nacl_optimum_mid1_trait predicate: is a object: nacl_optimum description: NaCl optimum mid1 is a quantitative bin of the NaCl-optimum phenotype. evidence: - reference: DOI:10.1093/femsre/fuy009 snippet: optimal NaCl notes: Supports the 1–3% optimum as a value within the NaCl-optimum distribution. predicate_id: rdfs:subClassOf - subject: nacl_optimum_mid1_trait predicate: defines object: slight_halophile_physiology description: A 1-3% (w/v) NaCl optimum defines slight-halophile/halotolerant physiology. evidence: - reference: DOI:10.3390/biotech14020049 notes: '"slight halophiles (0.2-0.5 M or 1-3% NaCl)" - supports trait scope/boundary.' predicate_id: METPO:2007500 - subject: slight_halophile_physiology predicate: associated with object: salt_in_strategy description: Slight-halophile physiology is broadly associated with the salt-in (K+ accumulation) strategy. evidence: - reference: DOI:10.3389/frmbi.2023.1329925 notes: '"The salt-in strategy involves maintaining a high intracellular concentration of inorganic salts, mainly potassium" - general mechanism across halotolerant/halophilic microbes.' predicate_id: biolink:associated_with - subject: slight_halophile_physiology predicate: associated with object: compatible_solute_strategy description: Slight-halophile physiology is broadly associated with the compatible-solute (salt-out) strategy. evidence: - reference: DOI:10.3389/frmbi.2023.1329925 notes: '"The salt-out strategy relies on biosynthesis or uptake of compatible solutes" - general osmoadaptation mechanism.' predicate_id: biolink:associated_with - subject: elevated_nacl predicate: induces accumulation of object: glycine_betaine description: Rising external NaCl increases intracellular glycine betaine. evidence: - reference: DOI:10.1128/aem.00145-24 notes: '"The intracellular content of compatible solutes, including glycine betaine, glutamate, and proline, increases with rising salinity levels" - directional relationship is broadly applicable.' - subject: elevated_nacl predicate: induces accumulation of object: l_proline description: Rising external NaCl increases intracellular L-proline. evidence: - reference: DOI:10.1128/aem.00145-24 notes: '"The intracellular content of compatible solutes, including glycine betaine, glutamate, and proline, increases with rising salinity levels" - proline is a general osmolyte.' curation_history: - timestamp: '2026-05-05T01:35:46.834129+00:00' curator: seed_from_metpo action: SEEDED_FROM_METPO changes: imported from data/raw/metpo.owl (CLASS) llm_assisted: false - timestamp: '2026-05-12T10:00:00-07:00' curator: claude action: CURATED_CAUSAL_GRAPH changes: Added DOI-backed definition and causal graph linking seawater-range NaCl and modest osmoadaptation to the slight-halophile NaCl-optimum bin. llm_assisted: true - timestamp: '2026-05-20T03:35:30Z' curator: claude action: GROUND_CAUSAL_PREDICATES changes: Grounded 2 causal-edge predicate_id field(s) via mappings/predicate_grounding.tsv (METPO:2000202×1, rdfs:subClassOf×1). llm_assisted: true - timestamp: '2026-06-23T00:00:00Z' curator: claude action: ENRICH_CAUSAL_GRAPH changes: Added 5 evidence-backed generic edges (6 new nodes) from the deep-research report. llm_assisted: true - timestamp: '2026-06-24T17:21:10Z' curator: claude action: GROUND_CAUSAL_PREDICATES changes: Grounded 3 causal-edge predicate_id field(s) via mappings/predicate_grounding.tsv (biolink:associated_with×2, METPO:2007500×1). llm_assisted: true - timestamp: '2026-06-24T17:23:31Z' curator: claude action: GROUND_CAUSAL_NODES changes: Grounded 1 causal-node grounding field(s) via mappings/node_grounding.tsv (CHEBI:17750×1). llm_assisted: true