Synthesis and Characterization of DNA Fluorescent Probes Containing a Single Site-Specific Stereoisomer of <i>anti</i>-Benzo[<i>a</i>]pyrene Diol Epoxide-<i>N</i><sup>2</sup>-dG
Bibliographic record
Abstract
We present a comprehensive study of synthesis and characterization of DNA probes containing covalently bound benzo[a]pyrene diol epoxide (BPDE) isomers at a defined site. Short oligonucleotides of 16mers containing a single trans-(+)- or trans-(-)-anti-BPDE-N(2)-guanine adducts (BPDE-16mer) were first synthesized and then ligated with a fluorescently labeled single-stranded oligonucleotide. The ligation products (double-stranded or single-stranded 90mers) contained a single BPDE adduct of defined stereochemistry and a fluorescent label. The BPDE adduct could be recognized by a specific antibody, and the fluorescent label was useful for highly sensitive laser-induced fluorescence detection. The incorporation of single BPDE in the 16mers was validated by liquid chromatography, UV spectroscopy, and tandem mass spectrometry analysis. The stereochemistry of the single BPDE adducts in the 16mers was further identified by enzyme digestion-coupled stereoselective chromatography analysis. The ligation of BPDE-16mer with normal oligonucleotides for the synthesis of tetramethylrhodamine (TMR)-BPDE-90mers was evaluated. It was found that the modification of the 16mer by anti-BPDE could significantly reduce the ligation yield of ds90mer and lead to the formation of gapped DNA. The incorporation of a single anti-BPDE adduct in ligated ds90mers was confirmed using an antibody specific to the anti-BPDE-dG and affinity capillary electrophoresis. The detection limits of the TMR-BPDE-90mers by capillary electrophoresis coupled with laser-induced fluorescence are below 4 x 10(-19) mol.
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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 | 0.001 | 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 | 0.001 |
| 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".