New Polyketide Congeners with Antibacterial Activities from an Endophytic Fungus Stemphylium globuliferum 17035 (China General Microbiological Culture Collection Center No. 40666)
Bibliographic record
Abstract
Four new polyketides, heterocornol Y (1), stemphyindan (2), pestalospirane C (3), and stemphyspyrane (4), along with five known ones (5–9) were isolated from the endophytic fungus Stemphylium globuliferum 17035 (SG17035) based on the One Strain Many Compounds (OSMAC) strategy allied with an LC-MS approach. These structures were elucidated through extensive spectroscopic analyses, single-crystal X-ray diffraction, and 13C NMR-DP4 analysis. Pestalospirane C (3) and stemphyspyrane (4) featured unprecedented spiroketal skeletons. In addition, the putative biosynthetic logic for compounds 1–4 was proposed. Antibacterial and cytotoxic activities of compounds 1–9 were evaluated. Stemphyspyrane (4) displayed promising antibacterial activity against different pathogens, especially against Staphylococcus aureus, Porphyromonas gingivalis, and methicillin-resistant Staphylococcus aureus (MRSA) with MIC values of 3.125 μM, 6.25 μM, and 12.5 μM, respectively. It is promising as an antibacterial agent for further optimization.
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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 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 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 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 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".