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Record W1498880590 · doi:10.1002/9780470514344.ch5

Origins of Secondary Metabolism

2007· review· en· W1498880590 on OpenAlex
Thomas Cavalier‐Smith

Why this work is in the frame

A frame that forgets how it found something cannot be audited. These are the routes that admitted this work.

affAt least one author lists a Canadian institution in the pinned OpenAlex snapshot.

Bibliographic record

VenueNovartis Foundation symposium · 2007
Typereview
Languageen
FieldBiochemistry, Genetics and Molecular Biology
TopicPhotosynthetic Processes and Mechanisms
Canadian institutionsUniversity of British Columbia
Fundersnot available
KeywordsSecondary metabolismBiologyPhylogeneticsPhylogenetic treeContext (archaeology)ArchaeaSecondary metabolitePhylumEvolutionary biologyEcologyGeneGenetics

Abstract

fetched live from OpenAlex

Secondary metabolites generally benefit their producers as poisons that protect them against competitors, predators or parasites. They are produced from universally present precursors (most often acetyl-CoA, amino acids or shikimate) by specific enzymes that probably arose by the duplication and divergence of genes originally coding for primary metabolism. Most secondary metabolites are restricted to single major taxa on the universal phylogenetic tree and so probably originated only once. But different secondary metabolic pathways have originated from different ancestral enzymes at radically different times in evolution. Secondary metabolites are most abundantly produced by microorganisms in crowded habitats and by plants, fungi and sessile animals like sponges, where chemical defence and attack rather than physical escape or fighting are at a premium. The first secondary metabolites were probably antibiotics produced in microbial mats over 3500 million years ago. These first ecosystems probably consisted entirely of eubacteria: archaebacteria and eukaryotes arose much later. As a phylogenetic context for considering the earliest origins of antibiotics I summarize a cladistic analysis of the explosive eubacterial primary diversification. This suggests that the most primitive surviving cells are the photosynthetic heliobacteria. Study of these and of the nearly as primitive chloroflexibacteria, spirochaetes and deinobacteria may provide the best evidence on the origins of secondary and primary metabolism.

Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.

Full frame distilled prediction

Teacher imitation

Not calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.

metaresearch head score (Codex)0.000
metaresearch head score (Gemma)0.000
Version: codex-gemma-dda1882f352aValidation status: machine_predicted_unvalidated
Candidate categoriesMeta-epidemiology (narrow)
Consensus categoriesnone
DomainCandidate signal: none · Consensus signal: none
Study designCandidate signal: Other design · Consensus signal: none
GenreCandidate signal: Review · Consensus signal: Review
Teacher disagreement score0.937
Threshold uncertainty score1.000

Codex and Gemma teacher scores by category

CategoryCodexGemma
Metaresearch0.0000.000
Meta-epidemiology (narrow)0.0000.000
Meta-epidemiology (broad)0.0010.000
Bibliometrics0.0000.000
Science and technology studies0.0000.000
Scholarly communication0.0000.000
Open science0.0000.000
Research integrity0.0000.000
Insufficient payload (model declined to judge)0.0000.000

Machine scores (provisional)

The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.

Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.

Opus teacher head0.036
GPT teacher head0.341
Teacher spread0.305 · how far apart the two teachers sit on this one work
Validation statusscore_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from it