Genetic analysis of pigment production in the fungus <i>Exophiala dermatitidis</i>
Bibliographic record
Abstract
Abstract Exophiala dermatitidis is a polyextremotolerant black yeast species. E. dermatitidis produces 1,8 dihydroxynaphthalene (DHN) melanin via the Polyketide Synthase 1 ( PKS1 ) pathway enabling it to survive harmful conditions. This study focused on random mutagenesis to obtain albino ( alb ) and hyper-pigmented ( hyp ) mutants. Notably, all 17 alb mutants possessed mutations in PKS1 whereas the 133 hyper-pigmented ( hyp) mutants harbored mutations impacting a range of functions. Cell morphology and phenotypic assays showed additional differences between the alb and hyp mutants. Strikingly, three of the albino mutants ( alb1 , alb2 , and alb3 ) were conditional in that despite the presence of mutations in PKS1 they were able to produce melanin upon exposure to different carbon sources. These mutants otherwise shared similar cell morphology and growth patterns with the obligate albinos. No additional shared mutations were found among the conditional albinos. Temperature and UV irradiation assays demonstrated reduced growth of albino mutants at higher temperatures (i.e., 42°C) and a greater sensitivity to higher doses of UV. Single nucleotide variant (SNVs) calling showed that hyper-pigmented mutants had a greater number of SNVs compared to albino strains. To date this is the first study to generate and characterize conditional albino mutants in E. dermatitidis with the ability to recover melanin production.
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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) | 0.000 | 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 | 0.000 |
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".