Use of the Black Yeast <i>Phaeococcomyces</i> Fungal Melanin Model System for Preparation of 1,3,6,8‐Tetrahydroxynaphthalene and the Other Components of the DHN Fungal Melanin Pathway
Bibliographic record
Abstract
Compounds of the dihydroxynaphthalene (DHN) fungal melanin pathway are in short supply worldwide, especially 1,3,6,8‐tetrahydroxynaphthalene, the chemically unstable starting point of the pathway, and are not commercially available. This is becoming an impediment to physiological survey work in the DHN pathway. We describe the use of our black yeast Phaeococcomyces DHN melanin model system to produce sufficient amounts of 1,3,6,8‐tetrahydroxynaphthalene for physiological studies, using a simple modified culture method that uses an oxygen‐scavenging growth medium containing cysteine and thioglycollate, which is also sealed with an oxygen‐excluding layer of the black yeast. The medium also contains the DHN pathway reductase enzyme inhibitor tricyclazole, which causes excretion of 1,3,6,8‐tetrahydroxynaphthalene and 1,3,8‐dihydroxynaphthalene. The presence of oxygen scavengers and the thick yeast growth prevents oxidation of the hydroxynaphthalenes. Most of the other components of the DHN fungal melanin pathway can be produced using the black yeast or using a scytalone dehydratase negative mutant of the black yeast that accumulates scytalone.
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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) | 0.001 | 0.001 |
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".