Discovery of the Lipopeptides Albubactins A–H from <i>Streptomyces albidoflavus</i> RKJM0023 via Chemical Elicitation with Rhamnolipids and Synthesis of Albubactin A
Bibliographic record
Abstract
The marine tunicate-derived Streptomyces albidoflavus RKJM0023 was cultured in the presence of a rhamnolipid mixture in an effort to elicit the production of silent natural products. MS/MS-based molecular networking analysis enhanced with nonparametric statistics highlighted the upregulation of a molecular cluster (Kruskal–Wallis p = 1.6 e –6 for 1 ) in which no MS/MS features had library matches. Targeted isolation of these features resulted in the discovery of nine new N- acylated lipopeptides, albubactins A–H ( 1 – 8 ) each containing a unique glutamine tripeptide and a C -terminal ethyl ester moiety. Three related albubactin acids A–C ( 9 – 11 ) lacking the ethyl ester were also identified. NMR spectroscopy and UPLC-HR-ESI-MS/MS demonstrated that the albubactins were obtained as mixtures that shared a common m / z and differed only in their acylated terminal groups. Due to the complex spectroscopic elucidation with many overlapping shifts, a total synthesis of albubactin A ( 1 ) was completed and used to determine the absolute configuration of the new albubactins.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot 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.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.002 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| 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 teacher head, 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".