The DOI matches its Crossref record; 38 of the 39 references it cites were found in a registry or an index; 11 of the 45 sources its claims cite were checked for support.
Chemiexcitation of melanin derivatives induces DNA photoproducts long after UV exposure
Open accessAbstract
The dark side of melanin exposed: Sun worshippers may have more to worry about than the DNA damage that occurs while they're relaxing on the beach. It seems that the DNA photoproducts responsible for cancer-causing mutations in skin cells continue to be generated for hours after sunlight exposure. Premi et al. find that a key mediator of this delayed damage is melanin, a pigment thought to protect against cancer (see the Perspective by Taylor). They propose a “chemiexcitation” model in which reactive oxygen and nitrogen species induced by ultraviolet light excite an electron in melanin fragments. This energy is then transferred to DNA, inducing the same damage as ultraviolet light, but in the dark. Conceivably, this energy could be dissipated by adding quenchers to sunscreens. Science , this issue p. 842 ; see also p. 824
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11 of 45 cited sources checked · 3 supported · 0 flagged · accuracy not yet measured
The cited sources that could be checked couldn’t confirm or dispute this claim.
In the paper
“The melanin requirement suggests that the NO• requirement in melanocytes is distinct from that observed in cultured keratinocytes (18).”
§ Chemiexcitation of Melanin Derivatives Induces DNA Photoproducts Long after UV Exposure > Photochemical Pathway
What the sources say
- Could not verifycites [18] sourceExperimental — accuracy not yet measured
The Discussion (page unavailable) describes UVA-induced reactive oxygen species in keratinocytes as arising primarily through Nox1-based NADPH oxidase. It does not address a nitric oxide requirement in keratinocytes or compare one with melanocytes; searches for nitric oxide, NO synthase, and nitration found no passage supporting that comparison. (LLM, conf=0.75)
Strength:hedged· not yet calibratedCausal:correlational· not yet calibratedTests✓ Asserted: passes✓ Checkable: passes? Load-bearing: unclear✓ Based: passes- Could not verify
The cited sources support only part of this claim — read each source’s verdict below.
In the paper
“Braf-mutant mice develop 10 times more spontaneous melanomas if they carry the pheomelanin-associated Mc1re/e allele (4).”
§ Chemiexcitation of Melanin Derivatives Induces DNA Photoproducts Long after UV Exposure > Abstract
What the sources say
- Partly supportedcites [4] sourceExperimental — accuracy not yet measured
The paper’s results passage (labelled Abstract; page unavailable) reports that red Mc1re/e Braf-mutant mice developed melanomas without UV exposure at a higher rate than black Braf-mutant mice, with more than 50% of red mice having tumors after one year. Our copy does not give a tenfold comparison, so the precise magnitude attributed to the paper is not supported. (LLM, conf=0.88)
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The cited sources support only part of this claim — read each source’s verdict below.
In the paper
“This double nature would explain the apparent cancer-facilitating effects of melanin seen in mice and in human epidemiology (2-4, 6).”
§ Chemiexcitation of Melanin Derivatives Induces DNA Photoproducts Long after UV Exposure > Proposed Scheme for the Participation of Melanin in Melanoma Development
What the sources say
- Not checked — no full text of the sourcecites [2] source
- Supportedcites [3] source
The Discussion describes melanin’s protective role in darker skin alongside its melanoma-promoting role in the mouse model. It also presents the mouse findings as a potential explanation for human observations, including melanoma risks associated with UVA tanning and pigmented nevi. The claim’s tentative wording matches that interpretation. (LLM, conf=0.90)
- Supportedcites [4] source
The paper’s Abstract (page not provided) reports UV-independent melanoma and oxidative damage linked to the pheomelanin pathway in red mice, while also describing melanin’s UV-protective role. It connects that proposed carcinogenic pathway to the elevated melanoma risk observed in red-haired, fair-skinned humans. The citing sentence’s tentative “would explain” matches the paper’s qualified interpretation. (LLM, conf=0.87)
- Partly supportedcites [6] sourceExperimental — accuracy not yet measured
The Discussion (page unavailable) describes a balance between melanin’s protection and photosensitizing damage, and suggests photosensitization may contribute to the elevated skin-cancer risk associated with red or blonde hair. It also proposes that melanin-related cell death could favor expansion of mutant cells. The paper does not report cancer-facilitating effects of melanin in mice; its mouse experiments measured UV-induced cell death, not cancer. (LLM, conf=0.82)
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesThe cited sources support only part of this claim — read each source’s verdict below.
In the paper
“Yet melanin's ROS generating properties do not explain its role in melanoma development because most mutations in human melanomas display the UV signature of C →T substitutions at sites of adjacent pyrimidines (8, 9).”
§ Chemiexcitation of Melanin Derivatives Induces DNA Photoproducts Long after UV Exposure > Abstract
What the sources say
- Partly supportedcites [8] sourceExperimental — accuracy not yet measured
The Introduction and “Canonical Mutations vs Signature Mutations” section report a preponderance of UV-signature mutations in melanomas from sun-exposed body sites. The claim omits that restriction and extends the finding to human melanomas generally. Page numbers are unavailable in our copy. (LLM, conf=0.88)
- Partly supportedcites [9] sourceExperimental — accuracy not yet measured
The Results (Landscape of nonsynonymous somatic mutations; page unavailable) report an excess of UV-linked C>T mutations at dipyrimidines in sun-exposed melanomas. The Discussion says the UV signature was not detected in acral, mucosal, or ocular melanomas. Thus the source supports the signature in sun-exposed melanomas, but not the claim as stated for human melanomas generally. (LLM, conf=0.85)
Load-bearingStrength:plain· not yet calibratedTests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passes- Partly supported
Every source the paper cites for this claim was checked and supports it.
In the paper
“UVA-irradiated mice do not develop melanoma if they lack melanin (3)”
§ Chemiexcitation of Melanin Derivatives Induces DNA Photoproducts Long after UV Exposure > Abstract
What the sources say
- Supportedcites [3] source
The Results section (‘Ultraviolet B and Ultraviolet A dependence of melanoma’; page unavailable) reports that UVA did not initiate melanoma in albino mice, whereas it did in pigmented mice. This supports the claim for the mouse models and exposure conditions discussed in the paper. (LLM, conf=0.91)
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In the paper
“A O2•–-initiated radical chain reaction in lipids was one possible conduit (26), but inducing lipid peroxidation in isolated nuclei using cumene hydroperoxide did not appear to induce CPD in nuclear DNA (fig. S3).”
§ Chemiexcitation of Melanin Derivatives Induces DNA Photoproducts Long after UV Exposure > Electronically Excited Melanin as a Molecular Vector
What the sources say
- Not checked — no full text of the sourcecites [26] source
Load-bearingStrength:hedged· not yet calibratedTests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesA result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“Unexpectedly, melanin-containing murine melanocytes instead continued to generate CPD for at least three hours after UVA exposure, at which point generation was offset by DNA repair (Fig. 1B,C).”
§ Chemiexcitation of Melanin Derivatives Induces DNA Photoproducts Long after UV Exposure > Delayed Cyclobutane Pyrimidine Dimer Induction in Melanocytes
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In the paper
“The (TC + CT)/TT ratio in melanin-containing cells increased from the UVA-like 0.37 at 0 h (directly-induced CPD) to 1.33 in the CPD arising during the following 2 h (p = 0.027), a ratio more typical of cells irradiated with the higher-energy UVB.”
§ Chemiexcitation of Melanin Derivatives Induces DNA Photoproducts Long after UV Exposure > Cytosine-containing Dark CPD
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In the paper
“To determine if NO• is required for production of dark CPD, we inhibited iNOS by treating melanocytes with aminoguanidine. This resulted in complete suppression of dark CPD production (Fig. 3C).”
§ Chemiexcitation of Melanin Derivatives Induces DNA Photoproducts Long after UV Exposure > Photochemical Pathway
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In the paper
“In support of an additional UV role, we found that exposing melanin-containing melanocytes to UVA created as much nuclear and cytoplasmic nitrotyrosine in 30 min as had accumulated from basal induction over ~8 days (Fig. 3D,E) (fig. S2D) (see Methods).”
§ Chemiexcitation of Melanin Derivatives Induces DNA Photoproducts Long after UV Exposure > Photochemical Pathway
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In the paper
“Consistent with this, we found that for fibroblasts and for melanocytes derived from albino mice, the peak of CPD induction was reached immediately upon exposure, followed by slow nucleotide excision repair (Fig. 1A) (fig. S1A). (14).”
§ Chemiexcitation of Melanin Derivatives Induces DNA Photoproducts Long after UV Exposure > Delayed Cyclobutane Pyrimidine Dimer Induction in Melanocytes
Strength:plain· not yet calibratedCausal:direct· not yet calibratedTests✓ Asserted: passes✓ Checkable: passes? Load-bearing: unclear✓ Based: passesA result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“For human melanocytes in which there was a modest rate of CPD decline after exposure but which showed no obvious dark CPD, the dark CPD were revealed by siRNA knockdown of XPA or XPC transcripts (Fig. 1F).”
§ Chemiexcitation of Melanin Derivatives Induces DNA Photoproducts Long after UV Exposure > Delayed Cyclobutane Pyrimidine Dimer Induction in Melanocytes
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In the paper
“This analysis revealed that the delayed CPD in melanin-containing melanocytes included the cytosine-containing CPD that generate UV-signature C→T mutations (Fig. 2A,B).”
§ Chemiexcitation of Melanin Derivatives Induces DNA Photoproducts Long after UV Exposure > Cytosine-containing Dark CPD
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesA result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“Furthermore, in K14-Kitl mice homozygous for the inactive Mc1re/e allele, in which melanocytes synthesize red-yellow pheomelanin, both initial and dark CPD were twice as frequent as in black mice.”
§ Chemiexcitation of Melanin Derivatives Induces DNA Photoproducts Long after UV Exposure > Delayed Cyclobutane Pyrimidine Dimer Induction in Melanocytes
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesA result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“The NOX inhibitor VAS2870 also abolished production of dark CPD (Fig. 3B).”
§ Chemiexcitation of Melanin Derivatives Induces DNA Photoproducts Long after UV Exposure > Photochemical Pathway
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesA result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“For the higher-energy UVB, the majority of CPD in melanocytes were created in the dark even without repair knockdown (figs. S1E-H).”
§ Chemiexcitation of Melanin Derivatives Induces DNA Photoproducts Long after UV Exposure > Delayed Cyclobutane Pyrimidine Dimer Induction in Melanocytes
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesA result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“Knocking down excision repair of CPD using siRNA against Xpa or Xpc transcripts (corresponding to genes mutated in xeroderma pigmentosum) revealed that dark CPD constituted half of the total CPD (Fig. 1D).”
§ Chemiexcitation of Melanin Derivatives Induces DNA Photoproducts Long after UV Exposure > Delayed Cyclobutane Pyrimidine Dimer Induction in Melanocytes
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesIn the paper
“To test whether this triplet state is required for dark CPD, we added ethyl sorbate, a specific quencher of triplet states (26), to intact melanocytes after UVA exposure. We found that this treatment prevented production of dark CPD (Fig. 3H).”
§ Chemiexcitation of Melanin Derivatives Induces DNA Photoproducts Long after UV Exposure > Photochemical Pathway
What the sources say
- Not checked — no full text of the sourcecites [26] source
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesA result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“Unexpectedly we observed a 4-fold higher ratio of (TC + CT)/TT CPD in the delayed CPD compared to directly-induced CPD, which is suggestive of unusual chemistry.”
§ Chemiexcitation of Melanin Derivatives Induces DNA Photoproducts Long after UV Exposure > Cytosine-containing Dark CPD
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesA result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“We found that kojic acid, an inhibitor of tyrosinase, the rate-limiting enzyme in melanin synthesis, suppressed production of dark CPD by 85% (Fig. 3A).”
§ Chemiexcitation of Melanin Derivatives Induces DNA Photoproducts Long after UV Exposure > Photochemical Pathway
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesA result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“This result also indicated that delayed CPD resided in nuclear DNA.”
§ Chemiexcitation of Melanin Derivatives Induces DNA Photoproducts Long after UV Exposure > Delayed Cyclobutane Pyrimidine Dimer Induction in Melanocytes
Load-bearingStrength:hedged· not yet calibratedTests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesA result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“After exposure of these mice to UVA, the level of epidermal CPD at the 2 hour timepoint was 3 times greater than it was immediately after exposure (Fig. 1G,H).”
§ Chemiexcitation of Melanin Derivatives Induces DNA Photoproducts Long after UV Exposure > Delayed Cyclobutane Pyrimidine Dimer Induction in Melanocytes
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesA result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“Because melanin generates superoxide radical ion (O2•–) while it is being irradiated, we specifically scavenged it with TEMPOL and found that this also abolished the production of dark CPD after UVA (fig. S2C).”
§ Chemiexcitation of Melanin Derivatives Induces DNA Photoproducts Long after UV Exposure > Photochemical Pathway
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesA result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“Importantly, we found that CPD were generated in the complete absence of UV when we incubated plasmid DNA and peroxynitrite with melanin, DHICA, or 5SCD (Fig. 4B).”
§ Chemiexcitation of Melanin Derivatives Induces DNA Photoproducts Long after UV Exposure > Electronically Excited Melanin as a Molecular Vector
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesA result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“The level of CPD induced in the absence of UV was approximately equal to that generated in pure DNA by 25 kJ/m2 of UVA, an exposure about one-quarter of that required to produce a barely-perceptible sunburn (the “minimal erythema dose”).”
§ Chemiexcitation of Melanin Derivatives Induces DNA Photoproducts Long after UV Exposure > Electronically Excited Melanin as a Molecular Vector
Load-bearingStrength:plain· not yet calibratedTests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesA result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“The CPD created by oxidizing melanin or its monomers included the mutagenic cytosine-containing CPD (fig. S4D).”
§ Chemiexcitation of Melanin Derivatives Induces DNA Photoproducts Long after UV Exposure > Electronically Excited Melanin as a Molecular Vector
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesA result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“Fragmention of these HPLC fractions generated m/z peaks assignable to oxidation products of either structure 1 or 2 created by known oxidation reactions.”
§ Chemiexcitation of Melanin Derivatives Induces DNA Photoproducts Long after UV Exposure > Electronically Excited Melanin as a Molecular Vector
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesA result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“When we separated reaction products by HPLC and scanned the HPLC eluate by mass spectrometry in negative ion mode for the corresponding 224 m/z product, we observed a single peak eluting in the highly polar region of the buffer gradient (Fig. 4E).”
§ Chemiexcitation of Melanin Derivatives Induces DNA Photoproducts Long after UV Exposure > Electronically Excited Melanin as a Molecular Vector
Load-bearingStrength:plain· not yet calibratedTests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesA result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“Synthetic melanin oxidized with peroxynitrite and incubated with DBAS generated a chemiluminescence signal 100-fold larger than seen in melanocytes (Fig. 4A)(fig. S4A).”
§ Chemiexcitation of Melanin Derivatives Induces DNA Photoproducts Long after UV Exposure > Electronically Excited Melanin as a Molecular Vector
Load-bearingStrength:plain· not yet calibratedTests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesA result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“Cell-free experiments revealed that melanin polymer was rapidly solubilized after exposure to UVA or peroxynitrite (Fig. 4D).”
§ Chemiexcitation of Melanin Derivatives Induces DNA Photoproducts Long after UV Exposure > Electronically Excited Melanin as a Molecular Vector
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesA result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“After UVA exposure, 3D images reconstructed from serial planar images revealed granules inside the nucleus (Supplementary Movies S1 and S2).”
§ Chemiexcitation of Melanin Derivatives Induces DNA Photoproducts Long after UV Exposure > Electronically Excited Melanin as a Molecular Vector
Load-bearingStrength:plain· not yet calibratedTests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesIn the paper
“To further test melanin's ability to host a triplet state, we oxidized synthetic melanin with horseradish peroxidase in the presence of hydrogen peroxide, which generates dioxetane intermediates by a mechanism similar to that of peroxynitrite (24). This produced similar levels of chemiluminescence (Fig. 4A, fig. S4B).”
§ Chemiexcitation of Melanin Derivatives Induces DNA Photoproducts Long after UV Exposure > Electronically Excited Melanin as a Molecular Vector
What the sources say
- Not checked — no full text of the sourcecites [24] source
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesA result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“When we blocked the reactivity of DHICA's 6-membered ring by omitting an OH group (5-hydroxyindole-2-carboxylic acid) (fig. S6A), oxidation still produced chemiluminescence (fig. S6B,C) and CPD (fig. S6D), suggesting that 2 is the predominant product.”
§ Chemiexcitation of Melanin Derivatives Induces DNA Photoproducts Long after UV Exposure > Electronically Excited Melanin as a Molecular Vector
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesA result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“However we found that DBAS, which redirects triplet energy toward luminescence, reduced CPD production by 50-90% (Fig. 4C, fig. S4C).”
§ Chemiexcitation of Melanin Derivatives Induces DNA Photoproducts Long after UV Exposure > Electronically Excited Melanin as a Molecular Vector
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesA conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“Most epidermal cells were keratinocytes, which receive pigment from the melanocytes, suggesting that melanin content rather than synthesis was the crucial requirement for dark CPD induction.”
§ Chemiexcitation of Melanin Derivatives Induces DNA Photoproducts Long after UV Exposure > Delayed Cyclobutane Pyrimidine Dimer Induction in Melanocytes
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesA conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“This represents a ~400 fold spike in the flux of peroxynitrite per hour.”
§ Chemiexcitation of Melanin Derivatives Induces DNA Photoproducts Long after UV Exposure > Photochemical Pathway
Strength:plain· not yet calibratedCausal:direct· not yet calibratedTests✓ Asserted: passes✓ Checkable: passes? Load-bearing: unclear✓ Based: passesA conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“We conclude that pigmented melanocytes induce “dark CPD” after UV exposure ends.”
§ Chemiexcitation of Melanin Derivatives Induces DNA Photoproducts Long after UV Exposure > Delayed Cyclobutane Pyrimidine Dimer Induction in Melanocytes
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesA conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“These results provide direct evidence that UV-induced superoxide and nitric oxide lead to a high-energy triplet state moiety, which then creates a dark CPD by energy transfer.”
§ Chemiexcitation of Melanin Derivatives Induces DNA Photoproducts Long after UV Exposure > Photochemical Pathway
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesA conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“Our data suggest that this may be the case in skin.”
§ Chemiexcitation of Melanin Derivatives Induces DNA Photoproducts Long after UV Exposure > Proposed Scheme for the Participation of Melanin in Melanoma Development
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesA conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“suggesting that 2 is the predominant product.”
§ Chemiexcitation of Melanin Derivatives Induces DNA Photoproducts Long after UV Exposure > Electronically Excited Melanin as a Molecular Vector
Load-bearingStrength:hedged· not yet calibratedTests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesA conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“The consequence is that half or more of the CPD in a melanocyte arise after UV exposure ends.”
§ Chemiexcitation of Melanin Derivatives Induces DNA Photoproducts Long after UV Exposure > Proposed Scheme for the Participation of Melanin in Melanoma Development
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesIn the paper
“Melanin synthesis itself generates ROS, especially synthesis of pheomelanin (7).”
§ Chemiexcitation of Melanin Derivatives Induces DNA Photoproducts Long after UV Exposure > Abstract
What the sources say
- Not checked — no full text of the sourcecites [7] source
Strength:plain· not yet calibratedCausal:direct· not yet calibratedTests✓ Asserted: passes✓ Checkable: passes? Load-bearing: unclear✓ Based: passesA conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“In vivo the same appears to be true of keratinocytes, which receive melanosomes donated by melanocytes.”
§ Chemiexcitation of Melanin Derivatives Induces DNA Photoproducts Long after UV Exposure > Proposed Scheme for the Participation of Melanin in Melanoma Development
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes? Based: unclearA conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“Based on our mass spectrometry data with albino murine melanocytes (Fig. 2), this value is approximately 1 CPD per 24 kb of DNA created solely by oxidized melanin.”
§ Chemiexcitation of Melanin Derivatives Induces DNA Photoproducts Long after UV Exposure > Electronically Excited Melanin as a Molecular Vector
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesIn the paper
“Because ROS can be produced in cells for long periods after UVA exposure (19), we tested the ROS scavengers N-acetylcysteine and α-tocopherol (vitamin E).”
§ Chemiexcitation of Melanin Derivatives Induces DNA Photoproducts Long after UV Exposure > Photochemical Pathway
What the sources say
- Not checked — no full text of the sourcecites [19] source
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesA conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“Together, these results indicate that melanin and melanin fragments are capable of acting as the molecular vectors that acquire an electronically excited triplet state, probably at a carbonyl arising from a dioxetane intermediate.”
§ Chemiexcitation of Melanin Derivatives Induces DNA Photoproducts Long after UV Exposure > Electronically Excited Melanin as a Molecular Vector
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesIn the paper
“UVA generates primarily TT CPD, with TC and CT CPD together contributing only 10-30% of these three CPD types (13).”
§ Chemiexcitation of Melanin Derivatives Induces DNA Photoproducts Long after UV Exposure > Cytosine-containing Dark CPD
What the sources say
- Not checked — no full text of the sourcecites [13] source
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesA conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“If the same holds for human skin, this would mean that past measurements of CPD immediately after UV exposure have underestimated the consequences of UV exposure.”
§ Chemiexcitation of Melanin Derivatives Induces DNA Photoproducts Long after UV Exposure > Proposed Scheme for the Participation of Melanin in Melanoma Development
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes? Based: unclearA conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“We conclude that, in cells exposed to UV, melanin or its constituents are able to enter the nucleus.”
§ Chemiexcitation of Melanin Derivatives Induces DNA Photoproducts Long after UV Exposure > Electronically Excited Melanin as a Molecular Vector
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passes- The authors state this as an assumption: The dark cytoplasmic granules seen in unirradiated normal melanocytes are melanin aggregates located in melanosomes, coated vesicles, and endoplasmic reticulum.
- It may state two separate claims as one. 33
- Probably not a substantial claim. 11
The cited sources that could be checked couldn’t confirm or dispute this claim.
In the paper
“The UVB process was also dependent on melanin and thus it differs from the delayed production of CPD that has been reported occasionally in other cell types after UVC or UVB exposure (16-18).”
§ Chemiexcitation of Melanin Derivatives Induces DNA Photoproducts Long after UV Exposure > Delayed Cyclobutane Pyrimidine Dimer Induction in Melanocytes
What the sources say
- Not matchedcites [16]
Couldn’t be matched to a paper in Crossref, so it can’t be checked.
- Not checked — no full text of the sourcecites [17] source
- Could not verifycites [18] sourceExperimental — accuracy not yet measured
The UVA irradiation and NADPH oxidase sections describe reactive oxygen species in UVA-exposed keratinocytes, not UVB-induced dark CPDs. Searches for melanin, CPDs, and delayed CPD production after UVB or UVC found no passage addressing the claim in our copy. (LLM, conf=0.75)
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesIt may state two separate claims as one.
- Not matched
The cited sources support only part of this claim — read each source’s verdict below.
In the paper
“The lower-energy UVA (315-400 nm), which constitutes ~95% of the ultraviolet energy that penetrates the atmosphere, also induces melanoma in mice and in humans who use tanning beds, but it is inefficient at making the cytosine-containing CPD that cause C→T mutations (12, 13).”
§ Chemiexcitation of Melanin Derivatives Induces DNA Photoproducts Long after UV Exposure > Abstract
What the sources say
- Partly supportedcites [12] sourceExperimental — accuracy not yet measured
The Abstract Results report elevated melanoma odds among indoor tanners, including users of primarily UVA-emitting devices. The Discussion cautions that the study cannot determine whether UVA or UVB caused those associations. The paper does not report melanoma induction in mice or address cytosine-containing CPDs and C→T mutations. (LLM, conf=0.88)
- Not checked — no full text of the sourcecites [13] source
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesIt may state two separate claims as one.
- Rests on an assumption: UVA accounts for about 95% of the ultraviolet energy that reaches the Earth's surface.
- Partly supported
The cited sources support only part of this claim — read each source’s verdict below.
In the paper
“UV-irradiated melanin, especially pheomelanin, triggers apoptosis and production of reactive oxygen species (ROS) and DNA strand breaks (5, 6).”
§ Chemiexcitation of Melanin Derivatives Induces DNA Photoproducts Long after UV Exposure > Abstract
What the sources say
- Not checked — no full text of the sourcecites [5] source
- Partly supportedcites [6] sourceExperimental — accuracy not yet measured
The Abstract concludes that UV-irradiated melanin, particularly pheomelanin, photosensitizes nearby cells to apoptosis. It also says irradiated melanin generates reactive oxygen species in vitro or in cultured cells, which can indirectly cause DNA strand breaks. The claim overstates the strand-break finding: the Results report no detectable signal above background for single-strand breaks immediately after UV irradiation of mouse skin. (LLM, conf=0.88)
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesIt may state two separate claims as one.
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“UVA-irradiated melanocytes generated ultra-weak chemiluminescence for several hours post-irradiation and only in cells containing melanin (Fig. 3F,G).”
§ Chemiexcitation of Melanin Derivatives Induces DNA Photoproducts Long after UV Exposure > Photochemical Pathway
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesIt may state two separate claims as one.
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“Assays for 3-nitrotyrosine revealed that basal nitration activity was present even without UV, that it was located primarily in the nucleus, and that its appearance required melanin (Fig. 3D,E) (fig. S2D).”
§ Chemiexcitation of Melanin Derivatives Induces DNA Photoproducts Long after UV Exposure > Photochemical Pathway
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesIt may state two separate claims as one.
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“Human melanocytes also generated dark CPD after UVA or UVB exposure (Fig. 1E, fig. S1I) although there was inter-individual variation in the response, particularly for UVA.”
§ Chemiexcitation of Melanin Derivatives Induces DNA Photoproducts Long after UV Exposure > Delayed Cyclobutane Pyrimidine Dimer Induction in Melanocytes
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesIt may state two separate claims as one.
The paper states this without a source or data behind it here, so there is nothing to check it against. The quote shows it is in the paper.
In the paper
“Because DBAS diverts triplet energy to luminescence, this compound also blocked dark CPD (fig. S2E).”
§ Chemiexcitation of Melanin Derivatives Induces DNA Photoproducts Long after UV Exposure > Photochemical Pathway
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesIt may state two separate claims as one.
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“The former suppressed production of dark CPD by 64% and the latter abolished it (figs. S2A,B).”
§ Chemiexcitation of Melanin Derivatives Induces DNA Photoproducts Long after UV Exposure > Photochemical Pathway
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesIt may state two separate claims as one.
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“Unirradiated normal melanocytes but not albino melanocytes showed dark granules in the cytoplasm, especially in the perinuclear area (fig. S5).”
§ Chemiexcitation of Melanin Derivatives Induces DNA Photoproducts Long after UV Exposure > Electronically Excited Melanin as a Molecular Vector
Strength:plain· not yet calibratedTests✓ Asserted: passes✓ Checkable: passes? Load-bearing: unclear✓ Based: passesIt may state two separate claims as one.
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“The eumelanin monomer 5,6-dihydroxyindole-2-carboxylic acid (DHICA) and the pheomelanin monomer 5-S-cysteinyldopa (5SCD) also generated chemiluminescence when oxidized (Fig. 4A).”
§ Chemiexcitation of Melanin Derivatives Induces DNA Photoproducts Long after UV Exposure > Electronically Excited Melanin as a Molecular Vector
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesIt may state two separate claims as one.
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“Scanning this fraction of the HPLC eluate across the small-molecule region of the mass spectrometer revealed four principal m/z peaks, of which the second largest was 224 daltons (Fig. 4F).”
§ Chemiexcitation of Melanin Derivatives Induces DNA Photoproducts Long after UV Exposure > Electronically Excited Melanin as a Molecular Vector
Load-bearingStrength:plain· not yet calibratedTests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesProbably not a substantial claim. It may state two separate claims as one.
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“We found that chemiluminescence began immediately and proceeded for >10 min.”
§ Chemiexcitation of Melanin Derivatives Induces DNA Photoproducts Long after UV Exposure > Electronically Excited Melanin as a Molecular Vector
Strength:plain· not yet calibratedTests✓ Asserted: passes✓ Checkable: passes? Load-bearing: unclear✓ Based: passesIt may state two separate claims as one.
A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“CPD were inhibited to a level below that at 0 h, indicating that dark CPD were also induced during the irradiation itself.”
§ Chemiexcitation of Melanin Derivatives Induces DNA Photoproducts Long after UV Exposure > Photochemical Pathway
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesIt may state two separate claims as one.
A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“The negative result with albino melanocytes implicated melanin in the process and ruled out the involvement of photosensitizing compounds in the growth medium.”
§ Chemiexcitation of Melanin Derivatives Induces DNA Photoproducts Long after UV Exposure > Delayed Cyclobutane Pyrimidine Dimer Induction in Melanocytes
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesIt may state two separate claims as one.
A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“This suggests that pheomelanin is both a poorer shield against normal CPD formation and a more potent dark CPD generator.”
§ Chemiexcitation of Melanin Derivatives Induces DNA Photoproducts Long after UV Exposure > Delayed Cyclobutane Pyrimidine Dimer Induction in Melanocytes
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesIt may state two separate claims as one.
What the paper did — it cites no source for this, so there is none to check. The quote shows it is in the paper.
In the paper
“Mass spectrometry ruled out the possibilities that (i) the ELISA and comet assays cross-reacted with melanin-DNA adducts and (ii) the delayed CPD appearance reflected greater access of the antibody or endonuclease due to a change in DNA conformation after UV exposure.”
§ Chemiexcitation of Melanin Derivatives Induces DNA Photoproducts Long after UV Exposure > Cytosine-containing Dark CPD
Load-bearingStrength:plain· not yet calibratedTests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesIt may state two separate claims as one.
A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“This likely reflects genetic differences between the donors.”
§ Chemiexcitation of Melanin Derivatives Induces DNA Photoproducts Long after UV Exposure > Delayed Cyclobutane Pyrimidine Dimer Induction in Melanocytes
Strength:hedged· not yet calibratedCausal:conditional· not yet calibratedTests✓ Asserted: passes✓ Checkable: passes✗ Load-bearing: fails✗ Based: failsProbably not a substantial claim. The paper’s conclusions may not depend on it. The paper may give no reason why it holds.
In the paper
“The lifetime of triplet carbonyls is ~10 μs (24), so a signal persistent over the course of hours indicates ongoing creation.”
§ Chemiexcitation of Melanin Derivatives Induces DNA Photoproducts Long after UV Exposure > Photochemical Pathway
What the sources say
- Not checked — no full text of the sourcecites [24] source
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesIt may state two separate claims as one.
In the paper
“Blondes and redheads, who have a higher ratio of yellow pheomelanin to brown eumelanin in their skin and hair, have a 2-4 times greater risk for melanoma than dark-haired individuals and the pheomelanin/eumelanin ratio accounts for some of this risk (2).”
§ Chemiexcitation of Melanin Derivatives Induces DNA Photoproducts Long after UV Exposure > Abstract
What the sources say
- Not checked — no full text of the sourcecites [2] source
Strength:plain· not yet calibratedCausal:correlational· not yet calibratedTests✓ Asserted: passes✓ Checkable: passes? Load-bearing: unclear✓ Based: passesIt may state two separate claims as one.
A claim is checked only against the cited paper’s full text, never its abstract, and none is available for its sources.
In the paper
“Such mutations arise from cyclobutane pyrimidine dimers (CPD), which join adjacent pyrimidines to distort the DNA helix (10, 11);”
§ Chemiexcitation of Melanin Derivatives Induces DNA Photoproducts Long after UV Exposure > Abstract
What the sources say
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesIt may state two separate claims as one.
In the paper
“An effect of antioxidants on CPD detectable immediately after UV has been reported, but was linked to changes in chromatin structure (20).”
§ Chemiexcitation of Melanin Derivatives Induces DNA Photoproducts Long after UV Exposure > Photochemical Pathway
What the sources say
- Not checked — no full text of the sourcecites [20] source
Strength:plain· not yet calibratedCausal:correlational· not yet calibratedTests✓ Asserted: passes✓ Checkable: passes✗ Load-bearing: fails✓ Based: passesProbably not a substantial claim. The paper’s conclusions may not depend on it.
In the paper
“A diagnostic for excited triplet states is that their energy can also discharge via ultra-weak blue or green luminescence (23).”
§ Chemiexcitation of Melanin Derivatives Induces DNA Photoproducts Long after UV Exposure > Photochemical Pathway
What the sources say
- Not checked — no full text of the sourcecites [23] source
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesProbably not a substantial claim.
In the paper
“The DHICA analog of the predicted eumelanin degradation product (29) (Fig. 4E, structure 1) has a molecular weight of 225 daltons and would be highly polar.”
§ Chemiexcitation of Melanin Derivatives Induces DNA Photoproducts Long after UV Exposure > Electronically Excited Melanin as a Molecular Vector
What the sources say
- Not checked — no full text of the sourcecites [29] source
Strength:hedged· not yet calibratedTests✓ Asserted: passes✓ Checkable: passes? Load-bearing: unclear✓ Based: passesIt may state two separate claims as one.
A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“The sustained time course of dark CPD generation can be accounted for by the prolonged steps of UV-induction of NOX and iNOS, peroxynitrite-induced solubilization of melanin to fragments or release of pre-melanin monomers from UV-damaged melanosomes and vesicles, and migration to the nucleus.”
§ Chemiexcitation of Melanin Derivatives Induces DNA Photoproducts Long after UV Exposure > Proposed Scheme for the Participation of Melanin in Melanoma Development
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesIt may state two separate claims as one.
A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“A consequence of these events is that melanin may be carcinogenic as well as protective against cancer.”
§ Chemiexcitation of Melanin Derivatives Induces DNA Photoproducts Long after UV Exposure > Proposed Scheme for the Participation of Melanin in Melanoma Development
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesIt may state two separate claims as one.
In the paper
“An alternative reaction is formation of a dioxetane moiety at the pyrrole ring (32), also leading to a polar structure of 225 daltons (structure 2).”
§ Chemiexcitation of Melanin Derivatives Induces DNA Photoproducts Long after UV Exposure > Electronically Excited Melanin as a Molecular Vector
What the sources say
- Not checked — no full text of the sourcecites [32] source
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesIt may state two separate claims as one.
In the paper
“Melanin is an unusual polymer whose properties set the stage for the events we have described (33).”
§ Chemiexcitation of Melanin Derivatives Induces DNA Photoproducts Long after UV Exposure > Proposed Scheme for the Participation of Melanin in Melanoma Development
What the sources say
- Not checked — no full text of the sourcecites [33] source
Load-bearingStrength:plain· not yet calibratedTests✓ Asserted: passes✗ Checkable: fails✓ Load-bearing: passes✓ Based: passesProbably not a substantial claim. It may be too vague to check against evidence.
A claim is checked only against the cited paper’s full text, never its abstract, and none is available for its sources.
In the paper
“It was proposed long ago that chemiexcitation – the creation of chemical reaction products containing excited electrons that underlie bioluminescence in lower organisms – has broad importance in biology (22, 23).”
§ Chemiexcitation of Melanin Derivatives Induces DNA Photoproducts Long after UV Exposure > Proposed Scheme for the Participation of Melanin in Melanoma Development
What the sources say
Strength:plain· not yet calibratedTests✓ Asserted: passes✓ Checkable: passes✗ Load-bearing: fails✓ Based: passesProbably not a substantial claim. The paper’s conclusions may not depend on it.
A claim is checked only against the cited paper’s full text, never its abstract, and none is available for its sources.
In the paper
“UV exposure additionally excites the rings to an energy that, especially for pheomelanin, ejects an electron that is captured by oxygen to yield more O2•- (5, 34).”
§ Chemiexcitation of Melanin Derivatives Induces DNA Photoproducts Long after UV Exposure > Proposed Scheme for the Participation of Melanin in Melanoma Development
What the sources say
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesIt may state two separate claims as one.
In the paper
“Peroxynitrite's presence in the nucleus without UV exposure is plausible because synthesis of melanin monomers is a redox reaction that releases O2•– (7) and melanosomes are assembled in the perinuclear space.”
§ Chemiexcitation of Melanin Derivatives Induces DNA Photoproducts Long after UV Exposure > Photochemical Pathway
What the sources say
- Not checked — no full text of the sourcecites [7] source
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesProbably not a substantial claim. It may state two separate claims as one.
In the paper
“These monomers are lipophilic and are therefore potentially able to enter the nucleus, and are concentrated in perinuclear coated vesicles before transfer to melanosomes (27).”
§ Chemiexcitation of Melanin Derivatives Induces DNA Photoproducts Long after UV Exposure > Electronically Excited Melanin as a Molecular Vector
What the sources say
- Not checked — no full text of the sourcecites [27]
Strength:hedged· not yet calibratedTests✓ Asserted: passes✓ Checkable: passes? Load-bearing: unclear✓ Based: passesIt may state two separate claims as one.
A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“These evanescent electronically excited products transfer their triplet energy to DNA hours after the original UV exposure, creating mutagenic cyclobutane pyrimidine dimers in the dark.”
§ Chemiexcitation of Melanin Derivatives Induces DNA Photoproducts Long after UV Exposure > Proposed Scheme for the Participation of Melanin in Melanoma Development
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesIt may state two separate claims as one.
A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“In summary, we have shown that exposing melanin-containing cells to UV radiation induces superoxide and nitric oxide, causing an orders-of-magnitude peroxynitrite spike that degrades melanin, allows melanin-like granules to appear in the nucleus, and excites melanin derivatives to a triplet state that has the high energy of a UV photon (Fig. 5).”
§ Chemiexcitation of Melanin Derivatives Induces DNA Photoproducts Long after UV Exposure > Proposed Scheme for the Participation of Melanin in Melanoma Development
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesIt may state two separate claims as one.
In the paper
“A longer-lasting source of O2•– in cells is NADPH oxidase (NOX), which is rapidly induced by UVA (19).”
§ Chemiexcitation of Melanin Derivatives Induces DNA Photoproducts Long after UV Exposure > Photochemical Pathway
What the sources say
- Not checked — no full text of the sourcecites [19] source
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesIt may state two separate claims as one.
In the paper
“One of the few biologically-synthesized molecules that can initiate such “photochemistry in the dark” (22, 23) is peroxynitrite (ONOO–) (24), which is generated by the reaction of O2•– with nitric oxide (NO•).”
§ Chemiexcitation of Melanin Derivatives Induces DNA Photoproducts Long after UV Exposure > Photochemical Pathway
What the sources say
- Not checked — no full text of the sourcecites [24] source
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesProbably not a substantial claim.
A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“One benefit of dark photochemistry's slow course is that it allows intervention.”
§ Chemiexcitation of Melanin Derivatives Induces DNA Photoproducts Long after UV Exposure > Proposed Scheme for the Participation of Melanin in Melanoma Development
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesProbably not a substantial claim.
In the paper
“The pigment melanin protects against sunlight-induced burns, DNA damage, and skin cancer due to an unusually broad absorption spectrum and perhaps radical scavenging activity (1).”
§ Chemiexcitation of Melanin Derivatives Induces DNA Photoproducts Long after UV Exposure > Abstract
What the sources say
- Not checked — no full text of the sourcecites [1] source
Strength:hedged· not yet calibratedCausal:direct· not yet calibratedTests✓ Asserted: passes✓ Checkable: passes✗ Load-bearing: fails✓ Based: passesProbably not a substantial claim. The paper’s conclusions may not depend on it. It may state two separate claims as one.
In the paper
“NOX and the NO• generator iNOS are UV-inducible within minutes and are expressed in melanocytes, including nuclear NOX4 (25).”
§ Chemiexcitation of Melanin Derivatives Induces DNA Photoproducts Long after UV Exposure > Photochemical Pathway
What the sources say
- Not checked — no full text of the sourcecites [25] source
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesIt may state two separate claims as one.
In the paper
“A blocker of dark CPD, α-tocopherol (vitamin E), is not only an antioxidant but also inactivates dioxetanes by converting them to a pair of diols (35).”
§ Chemiexcitation of Melanin Derivatives Induces DNA Photoproducts Long after UV Exposure > Proposed Scheme for the Participation of Melanin in Melanoma Development
What the sources say
- Not checked — no full text of the sourcecites [35] source
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesIt may state two separate claims as one.
None of the sources cited for this claim have been checked yet.
In the paper
“Melanin polymer rapidly solubilizes when exposed to hydrogen peroxide (H2O2) (28) and its degradation by peroxidation or UV-photoionization has been proposed to involve dioxetane and triplet carbonyls (29, 30).”
§ Chemiexcitation of Melanin Derivatives Induces DNA Photoproducts Long after UV Exposure > Electronically Excited Melanin as a Molecular Vector
What the sources say
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesProbably not a substantial claim. It may state two separate claims as one.
The paper relies on this without support.
UVA accounts for about 95% of the ultraviolet energy that reaches the Earth's surface.
“The lower-energy UVA (315-400 nm), which constitutes ~95% of the ultraviolet energy that penetrates the atmosphere, also induces melanoma in mice and in humans who use tanning beds, but it is inefficient at making the cytosine-containing CPD that cause C→T mutations (12, 13).”
The paper relies on this without support.
Disorders of CPD repair, such as xeroderma pigmentosum, increase childhood melanoma risk by 10,000-fold.
“genetic disorders of CPD repair such as xeroderma pigmentosum elevate the risk for childhood melanoma by 10,000-fold.”
The paper relies on this without support.
Peroxynitrite and nitric oxide can diffuse far enough from where they are made to reach their target molecules.
“Peroxynitrite and NO• are stable enough to diffuse significant distances from the site of generation to the target molecule.”
The authors state this as an assumption.
The dark cytoplasmic granules seen in unirradiated normal melanocytes are melanin aggregates located in melanosomes, coated vesicles, and endoplasmic reticulum.
“We presume these are melanin aggregates in melanosomes, coated vesicles, and endoplasmic reticulum because they have the same size and cellular locations as granules seen in melanocytes immunostained for tyrosinase (31).”
Claims other papers make about this one
Each is checked against this paper’s own text: does it say what the citing paper says it does?
The cited source doesn’t support the claim as written.
In the citing paper
“This result suggests that melanin-like reactants might be creating dCPDs by a reaction other than the indole ring dioxetane proposed in reference (32).”
From Chemiexcitation: Mammalian Photochemistry in the Dark† (2023) · cites this paper as [32]
Checked by a reasoning model — may be wrong.
Experimental — accuracy not yet measuredThe source backs part of the claim, not all of it — or backs it for a different population, condition or comparison.
In the citing paper
“This means that UV-filtering melanin can be found in all keratinocytes of the epidermis whereas it is absent in corneal epidermal cells [ 70 ].”
From Faster DNA Repair of Ultraviolet-Induced Cyclobutane Pyrimidine Dimers and Lower Sensitivity to Apoptosis in Human Corneal Epithelial Cells than in Epidermal Keratinocytes (2016) · cites this paper as [70]
Experimental — accuracy not yet measuredThe source backs part of the claim, not all of it — or backs it for a different population, condition or comparison.
In the citing paper
“The generation of ROS and peroxynitrites, mainly in mouse melanocytes that only synthesize pheomelanin, contributes to the delayed induction of cyclobutane pyrimidine dimers, the major form of DNA photoproducts, post-UV exposure, which increases the risk for UV signature mutations that are prevalent in melanoma [ 20 ].”
From Differential Induction of Reactive Oxygen Species and Expression of Antioxidant Enzymes in Human Melanocytes Correlate with Melanin Content: Implications on the Response to Solar UV and Melanoma Susceptibility (2022) · cites this paper as [20]
Experimental — accuracy not yet measuredThe source backs part of the claim, not all of it — or backs it for a different population, condition or comparison.
In the citing paper
“a brief UV exposure activates the enzymes nitric oxide synthase (NOS) and NADPH oxidase (NOX) to generate the radicals nitric oxide (•NO) and superoxide (O2•−) for hours afterward; the mechanism of induction is still not known.”
From Chemiexcitation: Mammalian Photochemistry in the Dark† (2023) · cites this paper as [32]
Experimental — accuracy not yet measuredThe source backs part of the claim, not all of it — or backs it for a different population, condition or comparison.
In the citing paper
“That process was initiated by nitric oxide and superoxide, radicals triggered by ultraviolet light or inflammation.”
From Chemiexcitation: Mammalian Photochemistry in the Dark† (2023) · cites this paper as [32]
Experimental — accuracy not yet measured
The source backs part of the claim, not all of it — or backs it for a different population, condition or comparison.
In the citing paper
“Based on analogous reactions in the literature, it is proposed that ambient O2 adds to create a peroxyl radical, which then cyclizes to create a strained 4-atom ring containing C–O–O–C, termed a dioxetane”
From Chemiexcitation: Mammalian Photochemistry in the Dark† (2023) · cites this paper as [32]
Experimental — accuracy not yet measuredThe source backs part of the claim, not all of it — or backs it for a different population, condition or comparison.
In the citing paper
“In mammals, chemiexcitation was discovered as energy transferred directly from excited melanin to DNA, creating the lethal and carcinogenic cyclobutane pyrimidine dimer.”
From Chemiexcitation: Mammalian Photochemistry in the Dark† (2023) · cites this paper as [32]
Experimental — accuracy not yet measuredThe source backs part of the claim, not all of it — or backs it for a different population, condition or comparison.
In the citing paper
“The chemiexcitation events were discovered in melanocyte cell cultures and in murine skin, using a fluorescent triplet-state reporter to detect the transient triplet state, blocking these events with the radical scavenger vitamin E or the triplet-specific quencher sorbate, and identifying dCPDs using mass spectrometry and immunohistochemistry.”
From Chemiexcitation: Mammalian Photochemistry in the Dark† (2023) · cites this paper as [32]
Experimental — accuracy not yet measuredThe cited source says what the claim attributes to it.
In the citing paper
“Recently our laboratory discovered that chemiexciting the skin pigment melanin sends melanocytes down the path to melanoma even in the dark”
From Chemiexcitation: Mammalian Photochemistry in the Dark† (2023) · cites this paper as [32]
The cited source says what the claim attributes to it.
In the citing paper
“The pyrrole ring was implicated as the site of a dioxetane (Fig. 4c) (32); the catechol ring of eumelanin has also been proposed as a site for dioxetane formation (43).”
From Chemiexcitation: Mammalian Photochemistry in the Dark† (2023) · cites this paper as [32]
In the citing paper
“Pheomelanins have also been implicated in UV-radiation-independent carcinogenic contributions to melanomagenesis by inducing oxidative DNA damage [65,66,67].”
From “Fifty Shades” of Black and Red or How Carboxyl Groups Fine Tune Eumelanin and Pheomelanin Properties (2016) · cites this paper as [67]
In the citing paper
“This shows that MAA may have even greater potential for photoprotection over current filters”
From Mycosporine-Like Amino Acids for Skin Photoprotection (2019) · cites this paper as [5]
In the citing paper
“the recent discovery of delayed (also know as ‘dark’) CPD formation, which suggests that CPD can form for hours after exposure through a triplet photoexcitation mechanism [5]”
From Mycosporine-Like Amino Acids for Skin Photoprotection (2019) · cites this paper as [5]
In the citing paper
“Therefore, this work is a strong indication that the consequences of UVA exposure for the development of melanoma have been underestimated.”
From Sunlight damage to cellular DNA: focus on oxidatively generated lesions (2017) · cites this paper as [99]
In the citing paper
“Recently, it was demonstrated that CPDs could also continue to be generated in the skin for more than 3 h after exposure to UVA [99].”
From Sunlight damage to cellular DNA: focus on oxidatively generated lesions (2017) · cites this paper as [99]
In the citing paper
“UVB irradiation can cause the loss of cellular integrity, direct damage to DNA and trigger various cellular responses including apoptosis [3] and inflammation [4] in skin cells including melanocytes (MC).”
From Nrf2 in keratinocytes modulates UVB-induced DNA damage and apoptosis in melanocytes through MAPK signaling (2017) · cites this paper as [3]
In the citing paper
“ROS and reactive nitrogen species (RNS) generated in melanocytes in response to UVA radiation lead to the production of “dark CPDs” hours after UVA exposure74.”
From Mechanisms and prevention of UV‐induced melanoma (2018) · cites this paper as [74]
Citations
Cites
Exome sequencing identifies recurrent somatic RAC1 mutations in melanoma
Krauthammer, M., Kong, Y., Ha, B. H., Evans, P., Bacchiocchi, A., McCusker, J. P., Cheng, E., Davis, M. J., Goh, G., Choi, M., et al. (2012) · Nature Genetics · doi:10.1038/ng.2359 · Cited by 1,191
Self-citationThe physical and chemical properties of eumelanin
Meredith, P., & Sarna, T. (2006) · Pigment Cell Research · doi:10.1111/j.1600-0749.2006.00345.x · Cited by 1,033
Thymine Dimerization in DNA Is an Ultrafast Photoreaction
Schreier, W. J., Schrader, T. E., Koller, F. O., Gilch, P., Crespo-Hernández, C. E., Swaminathan, V. N., Carell, T., Zinth, W., & Kohler, B. (2007) · Science · doi:10.1126/science.1135428 · Cited by 550
Mitra, D., Luo, X., Morgan, A., Wang, J., Hoang, M. P., Lo, J., Guerrero, C. R., Lennerz, J. K., Mihm, M. C., Wargo, J. A., et al. (2012) · Nature · doi:10.1038/nature11624 · Cited by 497
Melanins and melanogenesis: Methods, standards, protocols
d'Ischia, M., Wakamatsu, K., Napolitano, A., Briganti, S., Garcia‐Borron, J., Kovacs, D., Meredith, P., Pezzella, A., Picardo, M., Sarna, T., et al. (2013) · Pigment Cell & Melanoma Research · doi:10.1111/pcmr.12121 · Cited by 484
Self-citationKollias, N., Sayre, R. M., Zeise, L., & Chedekel, M. R. (1991) · Journal of Photochemistry and Photobiology B: Biology · doi:10.1016/1011-1344(91)80147-a · Cited by 482
Douki, T., Reynaud-Angelin, A., Cadet, J., & Sage, E. (2003) · Biochemistry · doi:10.1021/bi034593c · Cited by 452
Self-citationBrash, D. E. (2015) · Photochemistry and Photobiology · doi:10.1111/php.12377 · Cited by 401
Self-citationIndoor Tanning and Risk of Melanoma: A Case-Control Study in a Highly Exposed Population
Lazovich, D., Vogel, R. I., Berwick, M., Weinstock, M. A., Anderson, K. E., & Warshaw, E. M. (2010) · Cancer Epidemiology, Biomarkers & Prevention · doi:10.1158/1055-9965.epi-09-1249 · Cited by 353
Douki, T., & Cadet, J. (2001) · Biochemistry · doi:10.1021/bi0022543 · Cited by 337
Self-citation
Flagged first, then by citations
1 of the 39 references couldn’t be matched to a known paper.
Cited by
Sorted by citations
Sies, H., Berndt, C., & Jones, D. P. (2017) · Annual Review of Biochemistry · doi:10.1146/annurev-biochem-061516-045037 · Cited by 3,520
Current state of melanoma diagnosis and treatment
Davis, L. E., Shalin, S. C., & Tackett, A. J. (2019) · Cancer Biology & Therapy · doi:10.1080/15384047.2019.1640032 · Cited by 986
Singlet Molecular Oxygen Reactions with Nucleic Acids, Lipids, and Proteins
Mascio, P. D., Martinez, G. R., Miyamoto, S., Ronsein, G. E., de Medeiros, M. H. G., & Cadet, J. (2019) · Chemical Reviews · doi:10.1021/acs.chemrev.8b00554 · Cited by 674
Whiteman, D. C., Green, A. C., & Olsen, C. M. (2016) · Journal of Investigative Dermatology · doi:10.1016/j.jid.2016.01.035 · Cited by 650
“, 2005), and there is increasing evidence that the UVA wavelengths preferentially emitted by solaria have carcinogenic potential (AbdelMalek and Cassidy, 2015; Premi et al., 2015; Tewari et al., 2012).”
BackgroundFlexible Hybrid Electronics for Digital Healthcare
Ma, Y., Zhang, Y., Cai, S., Han, Z., Liu, X., Wang, F., Cao, Y., Wang, Z., Li, H., Chen, Y., et al. (2020) · Advanced Materials · doi:10.1002/adma.201902062 · Cited by 620
Metadata
- Authors
- Premi, S., Wallisch, S., Mano, C. M., Weiner, A. B., Bacchiocchi, A., Wakamatsu, K., Bechara, E. J. H., Halaban, R., Douki, T., & Brash, D. E.
- Affiliations
- Yale University (US)
- Universidade de São Paulo (BR)
- Fujita Health University (JP)
- Yale Cancer Center (US)
- Université Joseph Fourier (FR)
- Corresponding author
- Bechara, Etelvino J. H.
- Douki, Thierry
- Brash, Douglas E.
- ORCID
- Venue
- Science
- Published
- 2015-02-20
- Volume
- 347
- Issue
- 6224
- Pages
- 842-847
- ISSN
- 0036-8075 (ISSN-L)
- 1095-9203
- PMC
- PMC4432913
- OpenAlex
- W2093971029
- Semantic Scholar
- 26c414be169fcb7ec90f18696beb5729a3815347
- Cited by
- 550
- References
- 39
- Citations by year
- 2026: 34 · 2025: 47 · 2024: 43 · 2023: 43 · 2022: 54 · 2021: 66 · 2020: 46 · 2019: 45 · 2018: 45 · 2017: 46 · 2016: 53 · 2015: 24
- FWCI
- 38.23
- Type
- journal article
- Language
- en
- Open access
- green
- www.ncbi.nlm.nih.gov
- Locations
- Science (publishedVersion)
- PubMed (publishedVersion)
- Europe PMC (PubMed Central) (acceptedVersion)
- PubMed Central (acceptedVersion)
- HAL (submittedVersion)
- Funders
- Department of Defense CDMRP (CA093473P1, CA093473)
- University of Veterinary Medicine, Vienna
- Fundacao de Amparo a Pesquisa do Estado de Sao Paulo
- FAPESP (06/56530-4)
- NIH (P50 CA121974, P30 DK34989)
- Topics
- Physical Sciences › Chemistry › Physical and Theoretical Chemistry › Photochemistry and Electron Transfer Studies
- Life Sciences › Biochemistry, Genetics and Molecular Biology › Cell Biology › melanin and skin pigmentation
- Health Sciences › Medicine › Dermatology › Skin Protection and Aging
- Keywords
- melanin, chemiexcitation, cyclobutane pyrimidine dimers, DNA photoproducts, melanoma, UVA, melanocytes, triplet state, reactive oxygen species, reactive nitrogen species, tanning beds
- MeSH terms
- Animals, Cells, Cultured, Cytosine, DNA, DNA Damage, Energy Transfer, Humans, Melanins, Melanocytes, Melanoma, Mice, Inbred C57BL, Mutation, Neoplasms, Radiation-Induced, Pyrimidine Dimers, Skin Neoplasms, Sunlight, Thymine, Ultraviolet Rays, Mutagenesis, Photons, Receptor, Melanocortin, Type 1, Mice
About these checks
Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.
A language model drew the claims from the paper on 2026-09-28, under version 3 of the claim definition (prompt extract-v3).
A second model labelled each claim on 2026-09-28 (model jev-1.13-20260917, definition revision gold-guideline-v0.2).
Cited sources are checked with a language model’s help (gpt-6-sol).
Statistics and arithmetic are recomputed, not judged.
Confidence bands are shown only for fields calibrated on our annotated test set. None is calibrated yet, so no band is shown.
What counts as a claim ›How we measure confidence ›How we check this ›
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