Characterization of Polyketide Metabolites from Foliar Endophytes of <i>Picea glauca</i>
Bibliographic record
Abstract
A collection of 250 foliar endophytes of Picea glauca (white spruce) yielded several isolates that produced metabolites toxic to Choristoneura fumiferana (spruce budworm). Three of these strains were selected for further study based on their ability to be cultured and produce secondary metabolites under laboratory conditions. The culture filtrate of each was extracted and analyzed by LC-MS and LC-NMR, and the major metabolites were isolated and characterized. Structures were elucidated by spectroscopic analyses including 2D NMR and HRMS and by comparison to literature data. In some cases the extract was methylated in order to facilitate separation, but the original natural structure was determined by comparing the NMR data of the isolated methylated product with that of the stop-flow NMR of the underivatized extract (i.e., 2a, 2b, and 4). Two of these metabolites, 1 and 2a, are new structures, 3 and 4 are reported here for the first time as fungal metabolites, and 5- 10 as known fungal metabolites from other species. Tyrosol (10) was the only common metabolite found in all three extracts but did not account for the observed toxicity to C. fumiferana.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
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.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".