Single-dose UV-C irradiation induces the formation of gamma-H2AX foci in the human cell line (MCF7) that are not resolved after 2 and 24 hours of recovery as determined by immunofluorescence microscopy
Bibliographic record
Abstract
The integrity of the genome is of utmost importance for proper functioning existence of all living systems. Genotoxic insults, such as UV-C radiation, may exert adverse effects on genomic integrity. Cells have developed a number of highly conserved repair mechanism to counteract the variety of mutagenic and cytotoxic DNA lesions induced by genotoxic agents. Phosphorylation of gamma-histone H2AX is a known DNA-repair signaling response to double- stranded breaks (DSBs); however, the formation of DSB by UV-C radiation is reported to be rare. We sought to determine whether a single dose of UV-C radiation (0.31 J/cm2, 254nm) can induce the formation of gamma-H2AX foci in the human cell line (MCF7) and determine the amount of DNA damage present after a recovery period of two and 24 hours by immunofluorescence microscopy. We also exposed cells to 50 nM of camptothecin (CPT), a DNA damaging agent, as a positive control. We found that similar to CPT, human cells exposed to UV-C radiation (0.31 J/cm2) showed upregulated gamma-H2AX foci at both 2 h and 24 h after the genotoxic insult. Cells exposed to this single dose showed significantly higher gamma-H2AX from non- treated cells and the extent of DNA damage remained the same between 2 and 24 h. Our results indicate that UV-C radiation is capable of inducing the formation of the DSB signaling foci gamma-H2AX and that cells are unable to repair the genotoxic insult within 24 h of recovery. This further indicates that human cell line (MCF7) may require longer than 24 hours to noticeably repair the extent of DNA damage induced by (0.31 J/cm2) of UV-C light.
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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) | 0.003 | 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".