Development of different human skin colors: A review highlighting photobiological and photobiophysical aspects

Juzeniene, Asta; Setlow, R. B.; Porojnicu, Alina Carmen; Steindal, Arnfinn Hykkerud; Moan, Johan Emelian

doi:10.1016/j.jphotobiol.2009.04.009

Cited by 27 publications

(30 citation statements)

References 131 publications

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“…We extended our studies on the photoinactivation of TYR to folic acid (PteGlu) and its oxidation products because the photodegradation of PteGlu, an important vitamin, has been proposed as one of the reasons for the development of skin tanning in evolution [48][49][50][51][52]. Photooxidation of PteGlu under UV-A radiation may be divided into three stages: (i) in the first phase, p-aminobenzoylglutamic acid (PABA-Glu) and 6-formylpterin (Fop) are photogenerated, with a pseudo-zero-order kinetics; (ii) in the second phase, Fop photoinduces the photooxidation of PteGlu and its degradation process is accelerated; (iii) in the third phase, the degradation of Fop to 6-carboxypterin (Cap) is the dominating process (Scheme 5) [53][54][55][56].…”

Section: Photoinactivation Of Tyrosinasementioning

confidence: 99%

Photosensitization of peptides and proteins by pterin derivatives

et al. 2017

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Proteins are one of the preferential targets of the photosensitized damaging effects of ultraviolet (UV) radiation on biological system. Pterins belong to a family of heterocyclic compounds, which are widespread in living systems and participate in relevant biological functions. In pathological conditions, such as vitiligo, oxidized pterins accumulate in the white skin patches of patients suffering this depigmentation disorder. It is known that pterins are able to photosensitize damage in nucleotides and DNA by type I (electron transfer) and type II (singlet oxygen) mechanisms. Recently, it has been demonstrated that proteins and its components may also be damaged when solutions containing both proteins and pterin are exposed to UV-A radiation. Therefore, given the biological and medical relevance of the photosensitizing properties of these molecules, we present in this article an overview of the capability of different pterin derivatives to photoinduce damage in proteins present in the skin, focusing our attention on the chemical modifications of tyrosine and tryptophan residues.

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Section: Photoinactivation Of Tyrosinasementioning

confidence: 99%

Photosensitization of peptides and proteins by pterin derivatives

et al. 2017

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“…18 Evidence for natural selection operating at low latitudes (establishing and maintaining dark pigmentation under high UVR conditions) and high latitudes (which favours the development of light pigmentation under low UVR conditions), suggests that human skin colouration is a Darwinian adaptation. 7,16 The gradient of skin colours observed from the equator to the poles consequently results from two clines operating over a spatially varying optimum of UVR distribution. 19 The association between skin pigmentation in indigenous populations and latitude is therefore traceable to the correlation between skin colour and the intensity of UVR exposure.…”

Section: Ultraviolet Radiation Protective Mechanismsmentioning

confidence: 99%

“…6 Vitamin D (1.25 dihydroxyvitamin D 3 ) in turn reduces the incidence of rheumatoid arthritis, coronary heart disease, diabetes, multiple sclerosis, osteomalacia, rickets, schizophrenia, autoimmune diseases and also several types of cancer. 7 Conversely, excessive UVR exposure can lead to malignant skin diseases including cancer and mitochondrial (mtDNA) and nuclear (nDNA) molecule damage. 8,9 It has furthermore been proposed that excessive UVR may have had far-reaching effects on mammalian evolutionary processes.…”

Section: Introductionmentioning

confidence: 99%

Assessing the photoprotective effects of red ochre on human skin by in vitro laboratory experiments

Rifkin¹,

d’Errico²,

Dayet³

et al. 2015

S. Afr. J. Sci.

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Archaeological indicators of cognitive complexity become increasingly prevalent during the African Middle Stone Age, with the habitual exploitation of red ochre widely viewed as a key feature of the emergence of modern human behaviour. Given that some of the uses of ochre remain ambiguous, we present the preliminary results of an ongoing study in which we explore the efficacy of red ochre as a photoprotective device or sunscreen. The capacity of ochre to inhibit the susceptibility of humans to the detrimental effects of ultraviolet radiation was confirmed through the in vitro calculation of the sun protection factor values of samples derived from the Kunene Region in Namibia and the Bokkeveld Group deposits, Western Cape Province, South Africa. Visible spectroscopy was employed to determine colourimetric parameters of samples and assess the correlation between ochre colour and sun protection factor. The possible role of ochre as a sunscreen agent for hominin populations, including modern humans, during the Middle Stone Age in Africa is explored. We conclude that the habitual use of red ochre as a photoprotective agent likely played a role in the ability of prehistoric humans to adapt to novel environmental circumstances.

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“…This dismissal has found its way into the literature (e.g., Juzeniene et al, 2009;Elias and Williams, 2013) and the human variation section of the American Anthropological Association's website (www.understandingrace.org=humvar=skin_01.html). While reasonable at the time, three major developments postdating Blum's dismissal make such claims dubious.…”

Section: Skin Cancer As a Selective Force In Skin Pigmentationmentioning

confidence: 99%

A life history perspective on skin cancer and the evolution of skin pigmentation

Osborne

Hames

2013

American J Phys Anthropol

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The ancestral state of human skin pigmentation evolved in response to high ultraviolet radiation (UVR) stress. Some argue that pigmentation evolved to limit folate photolysis, therein limiting neural tube defects. Pigmentation also protects against sunburn which decreases the efficiency of sweating and potentiates skin infection. Pigmentation increases the efficacy of skin as a barrier to infection. Skin cancer has been rejected or minimized as a selective pressure because it is believed to have little or no effect on mortality during reproductive years. This argument ignores evidence of human longevity as a derived life history trait and the adaptive value of investment in offspring and kin, particularly during the post-reproductive lifespan. Opponents argue that lifespan in prehistoric hunter-gatherers was too short to be relevant to the evolution of skin pigmentation. This argument is flawed in that it relies on estimates of longevity at birth rather than adolescence. When appropriate estimates are used, it is clear that human longevity has a deep evolutionary history. We use a life history perspective to demonstrate the value of skin pigmentation as an adaptation to skin cancer with the following points: UVR exposure increases dysregulation of gene expression in skin cells leading to immortal cell lines; cutaneous malignant melanoma (CMM) affects individuals throughout reproductive years; and lifespan was longer than has previously been acknowledged, providing the opportunity for kin selection. This hypothesis is not at odds with the folate or barrier hypotheses. We stress that the evolution of skin pigmentation is complex and is an ongoing process.

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Development of different human skin colors: A review highlighting photobiological and photobiophysical aspects

Cited by 27 publications

References 131 publications

Photosensitization of peptides and proteins by pterin derivatives

Photosensitization of peptides and proteins by pterin derivatives

Assessing the photoprotective effects of red ochre on human skin by in vitro laboratory experiments

A life history perspective on skin cancer and the evolution of skin pigmentation

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