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The New Phytologist Aug 2020
Topics: Betalains; Caryophyllales; Dioxygenases; Levodopa; Pigmentation
PubMed: 31782527
DOI: 10.1111/nph.16295 -
Cell Reports Aug 2023Hanly et al. and Nishida et al. use distinct approaches to provide exceptional lessons regarding the genetic, molecular, morphological, and biochemical bases of...
Hanly et al. and Nishida et al. use distinct approaches to provide exceptional lessons regarding the genetic, molecular, morphological, and biochemical bases of butterfly wing pigmentation. These mechanistic insights collectively have important implications for our understanding of phenotype evolution.
Topics: Animals; Butterflies; Pigmentation; Phenotype
PubMed: 37594895
DOI: 10.1016/j.celrep.2023.112981 -
British Journal of Anaesthesia Jan 2023Recent reports highlight potential inaccuracies of pulse oximetry in patients with various degrees of skin pigmentation. We summarise the literature, provide an overview...
Recent reports highlight potential inaccuracies of pulse oximetry in patients with various degrees of skin pigmentation. We summarise the literature, provide an overview of potential clinical implications, and provide insights into how pulse oximetry could be improved to mitigate against such potential shortcomings.
Topics: Humans; Skin Pigmentation; Oximetry; Oxygen
PubMed: 35430087
DOI: 10.1016/j.bja.2022.03.011 -
Philosophical Transactions of the Royal... Jun 2022Lewontin's 1972 article 'The apportionment of human diversity' described a key feature of human genetic diversity that would have profound impacts on conversations... (Review)
Review
Lewontin's 1972 article 'The apportionment of human diversity' described a key feature of human genetic diversity that would have profound impacts on conversations regarding genetics and race: the typical genetic locus varies much less between classical human race groupings than one might infer from inspecting the features historically used to define those races, like skin pigmentation. From this, Lewontin concluded: 'Human racial classification … is now seen to be of virtually no genetic or taxonomic significance' (p. 397). Here, 50 years after the paper's publication, the goal is to understand the origins and legacy of the paper. Aided by insights from published papers and interviews with several of Lewontin's contemporaries, I review the 1972 paper, asking about the intellectual background that led to the publication of the paper, the development of its impact, the critiques of the work and the work's application and limitations today. The hope is that by gaining a clearer understanding of the origin and reasoning of the paper, we might dispel various confusions about the result and sharpen an understanding of the enduring value and insight the result provides. This article is part of the theme issue 'Celebrating 50 years since Lewontin's apportionment of human diversity'.
Topics: Genetic Variation; Humans; Skin Pigmentation
PubMed: 35430890
DOI: 10.1098/rstb.2020.0406 -
G3 (Bethesda, Md.) Dec 2023The US standard for maize commercially grown for grain specifies that yellow corn can contain at maximum 5% corn of other colors. Inbred parents of commercial hybrids...
The US standard for maize commercially grown for grain specifies that yellow corn can contain at maximum 5% corn of other colors. Inbred parents of commercial hybrids typically have clear pericarp, but transgressive segregants in breeding populations can display variation in pericarp pigmentation. We identified 10 doubled haploid biparental populations segregating for pigmented pericarp and evaluated qualitative genetic models using chi-square tests of observed and expected frequencies. Pigmentation ranged from light to dark brown color, and pigmentation intensity was quantitatively measured across 1,327 inbred lines using hue calculated from RGB pixel values. Genetic mapping was used to identify loci associated with pigmentation intensity. For 9 populations, pigmentation inheritance best fit a hypothesis of a 2- or 3-gene epistatic model. Significant differences in pigment intensity were observed across populations. W606S-derived inbred lines with the darkest pericarp often had clear glumes, suggesting the presence of a novel P1-rw allele, a hypothesis supported by a significant quantitative trait locus peak at P1. A separate quantitative trait locus region on chromosome 2 between 221.64 and 226.66 Mbp was identified in LH82-derived populations, and the peak near p1 was absent. A genome-wide association study using 416 inbred lines from the Wisconsin Diversity panel with full genome resequencing revealed 4 significant associations including the region near P1. This study supports that pericarp pigmentation among dent maize inbreds can arise by transgressive segregation when pigmentation in the parental generation is absent and is partially explained by functional allelic variation at the P1 locus.
Topics: Zea mays; Genes, Plant; Genome-Wide Association Study; Plant Breeding; Pigmentation
PubMed: 37950891
DOI: 10.1093/g3journal/jkad256 -
International Journal of Molecular... May 2023The melanin pigments eumelanin (EM) and pheomelanin (PM), which are dark brown to black and yellow to reddish-brown, respectively, are widely found among vertebrates.... (Review)
Review
The melanin pigments eumelanin (EM) and pheomelanin (PM), which are dark brown to black and yellow to reddish-brown, respectively, are widely found among vertebrates. They are produced in melanocytes in the epidermis, hair follicles, the choroid, the iris, the inner ear, and other tissues. The diversity of colors in animals is mainly caused by the quantity and quality of their melanin, such as by the ratios of EM versus PM. We have developed micro-analytical methods to simultaneously measure EM and PM and used these to study the biochemical and genetic fundamentals of pigmentation. The photoreactivity of melanin has become a major focus of research because of the postulated relevance of EM and PM for the risk of UVA-induced melanoma. Our biochemical methods have found application in many clinical studies on genetic conditions associated with alterations in pigmentation. Recently, besides chemical degradative methods, other methods have been developed for the characterization of melanin, and these are also discussed here.
Topics: Animals; Melanins; Melanocytes; Pigmentation; Epidermis; Melanoma
PubMed: 37176019
DOI: 10.3390/ijms24098305 -
Pigment Cell & Melanoma Research Jul 2021The primary biological role of human skin pigmentation is as a mediator of penetration of ultraviolet radiation (UVR) into the deep layers of skin and the cutaneous... (Review)
Review
The primary biological role of human skin pigmentation is as a mediator of penetration of ultraviolet radiation (UVR) into the deep layers of skin and the cutaneous circulation. Since the origin of Homo sapiens, dark, protective constitutive pigmentation and strong tanning abilities have been favored under conditions of high UVR and represent the baseline condition for modern humans. The evolution of partly depigmented skin and variable tanning abilities has occurred multiple times in prehistory, as populations have dispersed into environments with lower and more seasonal UVR regimes, with unique complements of genes and cultural practices. The evolution of extremes of dark pigmentation and depigmentation has been rare and occurred only under conditions of extremely high or low environmental UVR, promoted by positive selection on variant pigmentation genes followed by limited gene flow. Over time, the evolution of human skin pigmentation has been influenced by the nature and course of human dispersals and modifications of cultural practices, which have modified the nature and actions of skin pigmentation genes. Throughout most of prehistory and history, the evolution of human skin pigmentation has been a contingent and non-deterministic process.
Topics: Biological Evolution; Culture; Environment; Human Migration; Humans; Selection, Genetic; Sex Characteristics; Skin Pigmentation
PubMed: 33825328
DOI: 10.1111/pcmr.12976 -
Photodiagnosis and Photodynamic Therapy Sep 2022The clinical impact of 5-aminolevulinic acid (5-ALA) fluorescence during resection of brain metastases is not yet clear.. Recent data demonstrated significantly lower...
INTRODUCTION
The clinical impact of 5-aminolevulinic acid (5-ALA) fluorescence during resection of brain metastases is not yet clear.. Recent data demonstrated significantly lower incidence of visible fluorescence in cerebral melanoma metastases (CMM) compared to other brain metastases (BM). The aim of this study was to investigate if characteristic melanoma features such as pigmentation, intratumoural hemosiderin and bleeding have an influence on visible fluorescence in CMM.
MATERIALS AND METHODS
A retrospective study of two neurosurgical centers was performed including adult patients with resection of CMM after preoperative administration of 5-ALA. Data on the fluorescence status (visible or no fluorescence), the fluorescence quality (strong, vague, none) and fluorescence homogeneity (homogeneous or heterogeneous) of each CMM were collected. The amount of melanin, hemosiderin and intratumoural bleeding was semi-quantitatively determined and automated computer-based calculation of the relative pigmented area was performed in fluorescing and non-fluorescing CMM samples.
RESULTS
Altogether, 29 CMM were surgically removed after 5-ALA administration. Visible fluorescence was detected in 8 CMM (28%), whereas no fluorescence was detected in 21 CMM (72%). In detail, 3 tumors (10%) showed strong fluorescence, 5 tumors (17%) revealed vague fluorescence and in 21 tumors (72%) no fluorescence was found. In total, 8 fluorescing and 25 non-fluorescing CMM samples were investigated. According to the semi-quantitatively calculated fluorescence status, no statistically significant difference in the median amount of melanin (p = 0.242), hemosiderin (p = 0.603) and bleeding (p = 0.762) between CMM samples with and without visible fluorescence was found. Moreover, the automatically assessed relative pigmented area did not show a statistically significant difference between samples with visible and no fluorescence (p = 0.966).
CONCLUSION
Our data indicate that 5-ALA fluorescence is not dependent on the amount of pigmentation, intratumoural hemosiderin and bleeding in CMM. We thus assume that other factors are responsible for the low rate of visible fluorescence in CMM.
Topics: Adult; Aminolevulinic Acid; Brain Neoplasms; Hemosiderin; Humans; Melanins; Melanoma; Photochemotherapy; Pigmentation; Retrospective Studies
PubMed: 35430323
DOI: 10.1016/j.pdpdt.2022.102864 -
Journal of Translational Medicine Apr 2024Melanocytes are dendritic cells localized in skin, eyes, hair follicles, ears, heart and central nervous system. They are characterized by the presence of melanosomes... (Review)
Review
Melanocytes are dendritic cells localized in skin, eyes, hair follicles, ears, heart and central nervous system. They are characterized by the presence of melanosomes enriched in melanin which are responsible for skin, eye and hair pigmentation. They also have different functions in photoprotection, immunity and sound perception. Melanocyte dysfunction can cause pigmentary disorders, hearing and vision impairments or increased cancer susceptibility. This review focuses on the role of melanocytes in homeostasis and disease, before discussing their potential in regenerative medicine applications, such as for disease modeling, drug testing or therapy development using stem cell technologies, tissue engineering and extracellular vesicles.
Topics: Regenerative Medicine; Melanocytes; Pigmentation; Melanins; Hair Follicle
PubMed: 38589876
DOI: 10.1186/s12967-024-05113-x -
Marine Drugs Sep 2019Haloarchaea are halophilic microorganisms belonging to the archaea domain that inhabit salty environments (mainly soils and water) all over the world. Most of the genera... (Review)
Review
Haloarchaea are halophilic microorganisms belonging to the archaea domain that inhabit salty environments (mainly soils and water) all over the world. Most of the genera included in this group can produce carotenoids at significant concentrations (even wild-type strains). The major carotenoid produced by the cells is bacterioruberin (and its derivatives), which is only produced by this kind of microbes and few bacteria, like . Nevertheless, the understanding of carotenoid metabolism in haloarchaea, its regulation, and the roles of carotenoid derivatives in this group of extreme microorganisms remains mostly unrevealed. Besides, potential biotechnological uses of haloarchaeal pigments are poorly explored. This work summarises what it has been described so far about carotenoids from haloarchaea and their production at mid- and large-scale, paying special attention to the most recent findings on the potential uses of haloarchaeal pigments in biomedicine.
Topics: Animals; Archaea; Bacteria; Biotechnology; Carotenoids; Extreme Environments; Humans; Pigmentation
PubMed: 31500208
DOI: 10.3390/md17090524