identifier: traitmech:000704 label: diauxic growth definition: A physiological phenotype in which a microbial population exhibits two successive growth phases associated with a switch from preferential use of one nutrient source to use of another as the first becomes limiting. definition_source: DOI:10.1371/journal.pone.0061686 trait_category: PHYSIOLOGY term_kind: CLASS mapping_status: PROPOSED parent_traits: - METPO:1000059 synonyms: - synonym_text: diauxie synonym_type: EXACT_SYNONYM source: DOI:10.1128/jb.164.2.866-871.1985 evidence: - reference: DOI:10.1371/journal.pone.0061686 snippet: However, a significant fraction of cells maintains a high rate of elongation and displays no detectable growth lag during the shift. notes: Boulineau et al. 2013, PMID:23637881, PMC3640066; scientific abstract. Introduction defines diauxic growth by sequential carbon-source use, supporting the definition's nutrient-switching differentia. Relevant Results, Discussion, Methods, actual Figure 2 and Text S1 prose were inspected. AB460 is an engineered MG1655 derivative; single-cell medium exchange is not the same assay as mixed-substrate batch growth. Population lag does not imply arrest of every cell. Contaminant-supported growth and model assumptions remain relevant. Text S1 DOC extraction loses embedded equations; no equation was visually verified or used as a curated mechanistic claim. - reference: DOI:10.1128/jb.164.2.866-871.1985 snippet: Azotobacter vinelandii exhibited diauxie when grown in a medium containing both acetate and glucose as carbon sources. notes: George et al. 1985, PMID:3863813, PMC214331; directly retrieved source-qualified MED abstract only. Acetate preference in this experiment contradicts a universal glucose-first requirement and supports the lexical name diauxie. Full paper and figures were not inspected; a full-text XML endpoint returned HTTP 500. This access failure is not evidence that full text does not exist. - reference: DOI:10.1128/jb.01571-06 snippet: Following recovery of growth on the alternative carbon or nitrogen source, RpoS protein concentrations declined rapidly to a basal level. notes: Sandercock and Page 2008, PMID:18055600, PMC2223558; scientific abstract. Relevant Methods/Results and actual Figure 3 support UW batch-culture acetate/glucose and ammonium/N2 transitions. This supports nutrient-source scope rather than sugars or carbon alone. Ammonium augmentation addresses an oxygen-limitation alternative for the stress response. RpoS dynamics are not a universal causal mechanism of diauxie; later PHB consumption was explicitly unmeasured. Publisher text and Figure 3 were accessible despite requests HTML 403 and Europe PMC XML 500 responses. - reference: DOI:10.1371/journal.pbio.1002041 snippet: many natural isolates of Saccharomyces cerevisiae display short or nonexistent diauxic lags when grown in mixtures of glucose (preferred) and galactose. notes: Wang et al. 2015, PMID:25626068, PMC4308108; scientific abstract, not the XML's preceding TOC teaser or separate Author Summary. Relevant Results, growth-curve Methods, actual Figure 1 and S1 EPS were inspected. Operational zero lag means the smoothed growth-rate curve has no local minimum, not simultaneous equal use of both substrates. Natural-origin growth panels and engineered reporter derivatives require separate provenance. Figure 1 caption says eleven strains but the image has twelve labels; no strain count is inferred here. The observations oppose mandatory positive lag. - reference: DOI:10.1038/msb.2013.11 snippet: Once glucose is depleted, the cells consume the earlier produced ethanol notes: Zampar et al. 2013, PMID:23549479, PMC3693829; Introduction, second paragraph, not an abstract quote. Relevant Results, culture and measurement Methods and actual Figure 1 were inspected. FY4 was initially supplied glucose and later consumed produced ethanol; the definition therefore does not require both nutrients to be supplied initially. Figure 1 distinguishes concentration observations from fitted rates. Intracellular flux ranges are model-constrained, not direct flux measurements; raw supplemental data and the full mechanistic analysis were not reanalyzed. discussions: - discussion_id: diauxie-scope-and-hierarchy prompt: Retain sequential nutrient use without imposing a universal lag or regulatory mechanism. kind: CURATION_TODO status: OPEN rationale: Boulineau's Introduction defines sequential carbon use, while lag-emphasizing accounts operationalize a narrower growth-curve pattern. Wang reports short or nonexistent lags; Sandercock and Page extend the observed scope to nitrogen-source transitions. The present definition uses the nutrient-switching sense and does not require glucose preference, a positive minimum lag, complete arrest of every cell or strictly zero secondary-substrate use. An arbitrary biphasic growth curve without nutrient-switching evidence is insufficient. Diauxic shift denotes the transition; polyauxie and unqualified diphasic growth are not exact synonyms. METPO:1000731 nutrient adaptation is a trophic-type class whose local record operationalizes chronic copiotroph/oligotroph nutrient regimes, not this temporal pattern. Phenotype is the conservative parent pending upstream hierarchy review. Generalist and specialist denote niche breadth; dormancy, carbon catabolite repression and generic resource-use predicates are not exact equivalents. posed_by: codex posed_date: '2026-10-11' - discussion_id: diauxie-provenance-and-mechanism prompt: Ground conditional examples and taxon-specific mechanisms before adding canonical taxa or a graph. kind: KNOWLEDGE_GAP status: OPEN rationale: The studies include laboratory strains and engineered reporter derivatives. No natural canonical example is asserted without primary strain provenance and authority-resolved taxon identity. No shared universal molecular mechanism or taxon-paired protein branch is established here. Gene presence, lac-locus annotation, RpoS expression or predicted flux alone cannot establish observed diauxic growth. It is conditional on culture and nutrients, not a fixed species identity or sequence-feature trait. Qualified MED and Crossref metadata for all five sources exposed no linked correction or retraction at the 2026-10-11 check; available primary pages were also inspected. This bounded check does not guarantee absence of notices; Wang's preprint link is not a correction. Canonical examples, causal graphs and external equivalences remain unasserted rather than being inferred from these observations. posed_by: codex posed_date: '2026-10-11' curation_history: - timestamp: '2026-10-11T23:42:36Z' curator: codex action: MINTED_TRAITMECH_ID changes: Added diauxic growth with five primary DOI-backed sources and directly checked snippets. Reserved 000704, v580 and 1065700-1065799 after ignored/hidden worktree and pending-PR checks. Sequential nutrient-use scope, variable lag, population-versus-cell distinctions and provenance limits are explicit. Existing traits unchanged; timestamp is the observed UTC curation decision. llm_assisted: true