Antagonism between Two Mechanisms of Antifungal Drug Resistance
Bibliographic record
Abstract
This study tested for interaction between two independently evolved mechanisms of fluconazole resistance in Saccharomyces cerevisiae. One set of strains was from a 400-generation evolution experiment, during which the concentration of fluconazole was increased from 16 to 256 microg/ml in four increments. At 100 generations, populations became fixed for resistance mutations in either of two transcriptional regulators, PDR1 or PDR3. At 400 generations, replicate populations became fixed for another resistance mutation in UNK1, an unmapped gene further increasing resistance. Another genotype used in this study came from a population placed initially in 128 microg/ml of fluconazole; this environment selects for resistance through loss of function at ERG3, resulting in altered sterol metabolism. Mutant strains carrying PDR1(r) or PDR3(r) were crossed with the erg3(r) mutant strain, and the doubly mutant, haploid offspring were identified. The double-mutant strains grew less well than the parent strains at all concentrations of fluconazole tested. In genome-wide assays of gene expression, several ABC transporter genes that were overexpressed in one parent and several ERG genes that were overexpressed in the other parent were also overexpressed in the double mutants. Of the 43 genes that were consistently overexpressed in the PDR1(r) parents at generation 100, however, 31 were not consistently overexpressed in the double mutants. Of these 31 genes, 30 were also not consistently overexpressed after a further 300 generations of evolution in the PDR1(r) parent populations. The two independently evolved mechanisms of fluconazole resistance are strongly antagonistic to one another.
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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) | 0.000 | 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 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".