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Head and Neck Pathology Mar 2019Black and brown pigmentation of the oral mucosa can occur due to a multitude of non-neoplastic causes. Endogenous or exogenous pigments may be responsible for oral... (Review)
Review
Black and brown pigmentation of the oral mucosa can occur due to a multitude of non-neoplastic causes. Endogenous or exogenous pigments may be responsible for oral discoloration which can range from innocuous to life-threatening in nature. Physiologic, reactive, and idiopathic melanin production seen in smoker's melanosis, drug-related discolorations, melanotic macule, melanoacanthoma and systemic diseases are presented. Exogenous sources of pigmentation such as amalgam tattoo and black hairy tongue are also discussed. Determining the significance of mucosal pigmented lesions may represent a diagnostic challenge for clinicians. Biopsy is indicated whenever the source of pigmentation cannot be definitively identified based on the clinical presentation.
Topics: Humans; Mouth Diseases; Mouth Mucosa; Pigmentation; Pigmentation Disorders
PubMed: 30671761
DOI: 10.1007/s12105-018-0980-9 -
Journal of Natural Medicines Jan 2020Carotenoids are tetraterpene pigments that are distributed in photosynthetic bacteria, some species of archaea and fungi, algae, plants, and animals. About 850 naturally... (Review)
Review
Carotenoids are tetraterpene pigments that are distributed in photosynthetic bacteria, some species of archaea and fungi, algae, plants, and animals. About 850 naturally occurring carotenoids had been reported up until 2018. Photosynthetic bacteria, fungi, algae, and plants can synthesize carotenoids de novo. Carotenoids are essential pigments in photosynthetic organs along with chlorophylls. Carotenoids also act as photo-protectors, antioxidants, color attractants, and precursors of plant hormones in non-photosynthetic organs of plants. Animals cannot synthesize carotenoids de novo, and so those found in animals are either directly accumulated from food or partly modified through metabolic reactions. So, animal carotenoids show structural diversity. Carotenoids in animals play important roles such precursors of vitamin A, photo-protectors, antioxidants, enhancers of immunity, and contributors to reproduction. In the present review, I describe the structural diversity, function, biosyntheses, and metabolism of natural carotenoids.
Topics: Animals; Carotenoids; Fungi; Pigmentation; Plants
PubMed: 31588965
DOI: 10.1007/s11418-019-01364-x -
International Journal of Biological... 2023Hair graying is a common and visible sign of aging resulting from decreased or absence of melanogenesis. Although it has been established that gray hair greatly impacts... (Review)
Review
Hair graying is a common and visible sign of aging resulting from decreased or absence of melanogenesis. Although it has been established that gray hair greatly impacts people's mental health and social life, there is no effective countermeasure other than hair dyes. It has long been thought that reversal of gray hair on a large scale is rare. However, a recent study reported that individual gray hair darkening is a common phenomenon, suggesting the possibility of large-scale reversal of gray hair. In this article, we summarize the regulation mechanism of melanogenesis and review existing cases of hair repigmentation caused by several factors, including monoclonal antibodies drugs, tyrosine kinase inhibitors (TKIs), immunomodulators, other drugs, micro-injury, and tumors, and speculate on the mechanisms behind them. This review offers some insights for further research into the modulation of melanogenesis and presents a novel perspective on the development of clinical therapies, with emphasis on topical treatments.
Topics: Humans; Hair; Hair Color; Hair Follicle; Melanocytes; Pigmentation; Administration, Topical; Mental Health
PubMed: 37781032
DOI: 10.7150/ijbs.86911 -
Trends in Ecology & Evolution Apr 2020Mammalian colors and color patterns are some of the most diverse and conspicuous traits found in nature and have been widely studied from genetic/developmental and... (Review)
Review
Mammalian colors and color patterns are some of the most diverse and conspicuous traits found in nature and have been widely studied from genetic/developmental and evolutionary perspectives. In this review we first discuss the proximate causes underlying variation in pigment type (i.e., color) and pigment distribution (i.e., color pattern) and highlight both processes as having a distinct developmental basis. Then, using multiple examples, we discuss ultimate factors that have driven the evolution of coloration differences in mammals, which include background matching, intra- and interspecific signaling, and physiological influences. Throughout, we outline bridges between developmental and functional investigatory approaches that help broaden knowledge of mammals' memorable external appearances, and we point out areas for future interdisciplinary research.
Topics: Animals; Biological Evolution; Color; Mammals; Phenotype; Pigmentation
PubMed: 31980234
DOI: 10.1016/j.tree.2019.12.008 -
Pigment Cell & Melanoma Research Jul 2021Skin complexion is among the most recognizable phenotypes between individuals and is mainly determined by the amount and type of melanin pigment deposited in the... (Review)
Review
Skin complexion is among the most recognizable phenotypes between individuals and is mainly determined by the amount and type of melanin pigment deposited in the epidermis. Persons with dark skin complexion have more of a brown/black pigment known as eumelanin in their epidermis whereas those with fair skin complexions have less. Epidermal eumelanin acts as a natural sunblock by preventing incoming UV photons from penetrating into the skin and therefore protects against UV mutagenesis. By understanding the signaling pathways and regulation of pigmentation, strategies can be developed to manipulate skin pigmentation to improve UV resistance and to diminish skin cancer risk.
Topics: Animals; Enzyme Inhibitors; Humans; Melanins; Pharmaceutical Preparations; Skin Pigmentation; Translational Research, Biomedical
PubMed: 33666358
DOI: 10.1111/pcmr.12969 -
Current Opinion in Genetics &... Aug 2021The order Odonata (dragonflies and damselflies) comprises diurnal insects with well-developed vision, showing diverse colors in adult wings and bodies. It is one of the... (Review)
Review
The order Odonata (dragonflies and damselflies) comprises diurnal insects with well-developed vision, showing diverse colors in adult wings and bodies. It is one of the most ancestral winged insect groups. Because Odonata species use visual cues to recognize each other, color patterns have been investigated from ecological and evolutionary viewpoints. Here we review the recent progress on molecular mechanisms of pigmentation, especially focused on light-blue coloration. Results from histology and pigment analysis showed that ommochrome pigments on the proximal layer and pteridine pigments on the distal layer of the epidermis are essential for light-blue coloration. We also summarize genes involved in the biosynthesis of three major insect pigments conserved across insects and discuss that gene-functional analysis deserves future studies.
Topics: Animals; Color; Odonata; Phenothiazines; Phenotype; Pigmentation; Wings, Animal
PubMed: 33482606
DOI: 10.1016/j.gde.2020.12.014 -
ELife Jun 2021Hair greying is a hallmark of aging generally believed to be irreversible and linked to psychological stress.
BACKGROUND
Hair greying is a hallmark of aging generally believed to be irreversible and linked to psychological stress.
METHODS
Here, we develop an approach to profile hair pigmentation patterns (HPPs) along individual human hair shafts, producing quantifiable physical timescales of rapid greying transitions.
RESULTS
Using this method, we show white/grey hairs that naturally regain pigmentation across sex, ethnicities, ages, and body regions, thereby quantitatively defining the reversibility of greying in humans. Molecularly, grey hairs upregulate proteins related to energy metabolism, mitochondria, and antioxidant defenses. Combining HPP profiling and proteomics on single hairs, we also report hair greying and reversal that can occur in parallel with psychological stressors. To generalize these observations, we develop a computational simulation, which suggests a threshold-based mechanism for the temporary reversibility of greying.
CONCLUSIONS
Overall, this new method to quantitatively map recent life history in HPPs provides an opportunity to longitudinally examine the influence of recent life exposures on human biology.
FUNDING
This work was supported by the Wharton Fund and NIH grants GM119793, MH119336, and AG066828 (MP).
Topics: Adolescent; Adult; Aging; Child; Chromosome Mapping; Hair; Hair Color; Humans; Middle Aged; Stress, Psychological; Young Adult
PubMed: 34155974
DOI: 10.7554/eLife.67437 -
Current Topics in Developmental Biology 2016In Drosophila, as well as in many other plants and animals, pigmentation is highly variable both within and between species. This variability, combined with powerful... (Review)
Review
In Drosophila, as well as in many other plants and animals, pigmentation is highly variable both within and between species. This variability, combined with powerful genetic and transgenic tools as well as knowledge of how pigment patterns are formed biochemically and developmentally, has made Drosophila pigmentation a premier system for investigating the genetic and molecular mechanisms responsible for phenotypic evolution. In this chapter, we review and synthesize findings from a rapidly growing body of case studies examining the genetic basis of pigmentation differences in the abdomen, thorax, wings, and pupal cases within and between Drosophila species. A core set of genes, including genes required for pigment synthesis (eg, yellow, ebony, tan, Dat) as well as developmental regulators of these genes (eg, bab1, bab2, omb, Dll, and wg), emerge as the primary sources of this variation, with most genes having been shown to contribute to pigmentation differences both within and between species. In cases where specific genetic changes contributing to pigmentation divergence were identified in these genes, the changes were always located in noncoding sequences and affected cis-regulatory activity. We conclude this chapter by discussing these and other lessons learned from evolutionary genetic studies of Drosophila pigmentation and identify topics we think should be the focus of future work with this model system.
Topics: Abdomen; Animals; Drosophila; Organ Specificity; Pigmentation; Pupa; Thorax; Wings, Animal
PubMed: 27282023
DOI: 10.1016/bs.ctdb.2016.03.004 -
ELife Jun 2021Analysing changes in hair pigmentation may lead to a better understanding of the impacts of 'life events' on human biology and aging.
Analysing changes in hair pigmentation may lead to a better understanding of the impacts of 'life events' on human biology and aging.
Topics: Aging; Hair; Hair Color; Humans; Pigmentation
PubMed: 34190044
DOI: 10.7554/eLife.70584 -
NTM Dec 2021
Topics: Ferrocyanides; Pigmentation
PubMed: 34491368
DOI: 10.1007/s00048-021-00311-w