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Phlebology Jul 2020Chronic venous insufficiency causes skin pigmentation of the leg ranging from small patches of mild dyschromia to extensive areas of severe skin pigmentation. It is...
INTRODUCTION
Chronic venous insufficiency causes skin pigmentation of the leg ranging from small patches of mild dyschromia to extensive areas of severe skin pigmentation. It is thought that the pigmentation is mainly due to haemosiderin or melanin deposition. Erythrodiapedesis which occurs as a result of venular hypertension causes erythrocytes to migrate across the microvascular network into the dermis.
METHODS
We categorized the grading of pigmentation into four grades: +, few spots; ++, pigmentation over gaiter area; +++, pigmentation involving leg and ankle; ++++, heavily pigmented (dark). Skin biopsies were taken from the patient while undergoing surgery; two biopsies were taken from each patient, one from apparently normal skin and other from the site of pigmentation. A total of 45 patients diagnosed as chronic venous insufficiency with pigmentation were included in the study and five patients included in control. The biopsy specimens were sent to pathology department for H&E, Perls stain and IHC for S100.
RESULTS
Majority of cases, i.e. 62% of limbs fall under (++) grade of pigmentation, followed by (+) grade of pigmentation in 20%, while (+++) and (++++) constitute 9% of the cases each. Increased melanin deposition was seen in 40 pigmented skin biopsies and 3 normal skin biopsies from the case group, and normal melanin deposition was seen in all the non-varicose controls.
CONCLUSION
We have tried to categorize pigmentation in chronic venous insufficiency into four grades. As the grade of pigmentation increases the per cent of cases with ulceration is increasing. It was observed that presence of melanin deposition irrespective of the grade of pigmentation was distributed more towards the advanced clinical classification (C5 and C6).
Topics: Adult; Biopsy; Cell Movement; Chronic Disease; Erythrocytes; Female; Hemosiderin; Humans; Leg; Male; Melanins; Microcirculation; Pigmentation; Severity of Illness Index; Skin; Skin Pigmentation; Venous Insufficiency
PubMed: 31699007
DOI: 10.1177/0268355519885471 -
Poultry Science Aug 2021Eggshell color is an important shell quality trait that influences consumer preference. It is also of particular importance with respect to sexual signaling and the... (Review)
Review
Eggshell color is an important shell quality trait that influences consumer preference. It is also of particular importance with respect to sexual signaling and the physiological and mechanical properties of shell pigment. Pigments include protoporphyrin IX, biliverdin, and traces of biliverdin zinc chelates, with brown eggs being notably rich in protoporphyrin IX, the synthesis of which has a marked effect on the intensity of brown eggshell color. This pigment is initially synthesized in the eggshell gland within the oviduct of laying hens and is subsequently deposited throughout the cuticular and calcareous layers of brown eggshell. In this review, we describe the factors affecting brown eggshell color and potential targets for the regulation of pigment synthesis. Protoporphyrin IX synthesis might be compromised by synthetase-mediated pigment synthesis, the redox status of the female birds, and regulation of the nuclear transcription factors associated with δ-aminolevulinic acid synthetase1. We believe that this review will provide a valuable reference for those engaged in studying eggshell depigmentation.
Topics: Animals; Biliverdine; Chickens; Egg Shell; Female; Ovum; Pigmentation
PubMed: 34214744
DOI: 10.1016/j.psj.2021.101273 -
Animal Genetics Dec 2020The study of skin color in cattle holds both economic and scientific interest. Several ocular diseases of cattle have been associated with low pigmentation of the...
The study of skin color in cattle holds both economic and scientific interest. Several ocular diseases of cattle have been associated with low pigmentation of the eyelids, including ocular squamous cell carcinoma and infectious keratoconjunctivitis, the two most common ocular diseases affecting cattle production. Although low eyelid pigmentation is a well-known risk factor for various ocular diseases, the genetic and biological basis of this relationship is largely unknown. We investigated the transcriptome of eyelid skin in Hereford cattle using RNA-sequencing technology. Two contrasting groups were evaluated: steers that were completely pigmented and steers with no pigmentation in both eyelids. Most of the up-regulated genes in pigmented samples are directly implicated in melanogenesis and melanosome development, whereas up-regulated genes in non-pigmented samples are implicated in cancer development and the immune system, among other functions. Interestingly, network analysis comparing pigmented vs. non-pigmented samples revealed significant differences in the co-expression patterns of genes related to melanosome, pigmentation and defense response to bacteria, showing higher gene activity, greater co-expression patterns and tighter co-regulation mechanisms in pigmented samples. Overall, our findings indicate that bovine eyelid pigmentation depends on the expression of many genes involved not only in pigmentation and melanosome function but also related to inflammatory response, infection and tumoral pathways.
Topics: Animals; Breeding; Cattle; Eye Diseases; Eyelids; Gene Expression; Male; Melanins; Melanosomes; Phenotype; Pigmentation; Transcriptome
PubMed: 33058316
DOI: 10.1111/age.13004 -
Journal of Visualized Experiments : JoVE Mar 2022Melanocytes are specialized neural crest-derived cells present in the epidermal skin. These cells synthesize melanin pigment that protects the genome from harmful...
Melanocytes are specialized neural crest-derived cells present in the epidermal skin. These cells synthesize melanin pigment that protects the genome from harmful ultraviolet radiations. Perturbations in melanocyte functioning lead to pigmentary disorders such as piebaldism, albinism, vitiligo, melasma, and melanoma. Zebrafish is an excellent model system to understand melanocyte functions. The presence of conspicuous pigmented melanocytes, ease of genetic manipulation, and availability of transgenic fluorescent lines facilitate the study of pigmentation. This study employs the use of wild-type and transgenic zebrafish lines that drive green fluorescent protein (GFP) expression under mitfa and tyrp1 promoters that mark various stages of melanocytes. Morpholino-based silencing of candidate genes is achieved to evaluate the phenotypic outcome on larval pigmentation and is applicable to screen for regulators of pigmentation. This protocol demonstrates the method from microinjection to imaging and fluorescence-activated cell sorting (FACS)-based dissection of phenotypes using two candidate genes, carbonic anhydrase 14 (Ca14) and a histone variant (H2afv), to comprehensively assess the pigmentation outcome. Further, this protocol demonstrates segregating candidate genes into melanocyte specifiers and differentiators that selectively alter melanocyte numbers and melanin content per cell, respectively.
Topics: Animals; Melanocytes; Pigmentation; Pigmentation Disorders; Reverse Genetics; Zebrafish
PubMed: 35312674
DOI: 10.3791/62955 -
Applied Microbiology and Biotechnology May 2021Ultraviolet radiation, continuously reaching our planet's surface, is a type of electromagnetic energy within the wavelength range of 10 to 400 nm. Despite essential for... (Review)
Review
Ultraviolet radiation, continuously reaching our planet's surface, is a type of electromagnetic energy within the wavelength range of 10 to 400 nm. Despite essential for all life on Earth, ultraviolet radiation may have severe adverse cellular effects, including DNA dimerization and production of reactive oxygen species. Radioresistant microorganisms can survive under high doses of ultraviolet radiation, enduring the direct and indirect effects on nucleic acids and other biomolecules. The synthesis and accumulation of photoprotective compounds are among the main strategies employed by radioresistant yeast species to bear the harmful effects of ultraviolet radiation. A correlation between pigments and resistance to ultraviolet radiation has been widely recognized in these microorganisms; however, there is still some debate on this topic, with non-pigmented strains sometimes being more resistant than their pigmented counterparts. In this review, we explore the role of photoprotective compounds-specifically, melanin, carotenoids, and mycosporines-and compare the differences found in resistance between pigmented and non-pigmented yeasts. We also discuss the biotechnological potential of these photoprotective compounds, with special emphasis on those produced by non-pigmented yeast strains, such as phytoene and phytofluene. The use of "-omics" approaches should further unveil the radioresistance mechanisms of non-pigmented yeasts, opening new opportunities for both research and commercial applications. KEY POINTS: • Updated knowledge on photoprotective compounds from radioresistant yeasts. • Differences on radioresistance between pigmented and non-pigmented yeasts. • Future prospects over the study of non-pigmented photoprotective compounds.
Topics: Melanins; Pigmentation; Ultraviolet Rays; Yeasts
PubMed: 33900423
DOI: 10.1007/s00253-021-11271-5 -
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 -
Heredity Nov 2021Pigmentation divergence between Drosophila species has emerged as a model trait for studying the genetic basis of phenotypic evolution, with genetic changes contributing...
Pigmentation divergence between Drosophila species has emerged as a model trait for studying the genetic basis of phenotypic evolution, with genetic changes contributing to pigmentation differences often mapping to genes in the pigment synthesis pathway and their regulators. These studies of Drosophila pigmentation have tended to focus on pigmentation changes in one body part for a particular pair of species, but changes in pigmentation are often observed in multiple body parts between the same pair of species. The similarities and differences of genetic changes responsible for divergent pigmentation in different body parts of the same species thus remain largely unknown. Here we compare the genetic basis of pigmentation divergence between Drosophila elegans and D. gunungcola in the wing, legs, and thorax. Prior work has shown that regions of the genome containing the pigmentation genes yellow and ebony influence the size of divergent male-specific wing spots between these two species. We find that these same two regions of the genome underlie differences in leg and thorax pigmentation; however, divergent alleles in these regions show differences in allelic dominance and epistasis among the three body parts. These complex patterns of inheritance can be explained by a model of evolution involving tissue-specific changes in the expression of Yellow and Ebony between D. elegans and D. gunungcola.
Topics: Alleles; Animals; Drosophila; Drosophila Proteins; Male; Pigmentation; Species Specificity; Thorax
PubMed: 34537820
DOI: 10.1038/s41437-021-00467-0 -
Journal of Experimental Botany Jan 2020Angiosperms that are biotically pollinated typically produce flowers with bright and contrasting colours that help to attract pollinators and hence contribute to the... (Review)
Review
Angiosperms that are biotically pollinated typically produce flowers with bright and contrasting colours that help to attract pollinators and hence contribute to the reproductive success of the species. This colourful array contrasts with the much less multicoloured reproductive structures of the four living gymnosperm lineages, which are mostly wind pollinated, though cycads and Gnetales are predominantly pollinated by insects that feed on surface fluids from the pollination drops. This review examines the possible evolutionary pathways and cryptic clues for flower colour in both living and fossil seed plants. It investigates how the ancestral flowering plants could have overcome the inevitable trade-off that exists between attracting pollinators and minimizing herbivory, and explores the possible evolutionary and biological inferences from the colours that occur in some living gymnosperms. The red colours present in the seed-cone bracts of some living conifers result from accumulation of anthocyanin pigments; their likely primary function is to help protect the growing plant tissues under particular environmental conditions. Thus, the visual cue provided by colour in flower petals could have first evolved as a secondary effect, probably post-dating the evolution of bee colour vision but occurring before the subsequent functional accumulation of a range of different flower pigments.
Topics: Animals; Biological Evolution; Color; Cycadopsida; Flowers; Fossils; Magnoliopsida; Pigmentation; Pollination; Seed Dispersal
PubMed: 31714579
DOI: 10.1093/jxb/erz479 -
Current Opinion in Genetics &... Aug 2021Skin pigment patterns of vertebrates are stunningly diverse, and nowhere more so than in teleost fishes. Several species, including relatives of zebrafish, recently... (Review)
Review
Skin pigment patterns of vertebrates are stunningly diverse, and nowhere more so than in teleost fishes. Several species, including relatives of zebrafish, recently evolved cichlid fishes of East Africa, clownfishes, deep sea fishes, and others are providing insights into pigment pattern evolution. This overview describes recent advances in understanding periodic patterns, like stripes and spots, the loss of patterns, and the role of cell-type diversification in generating pigmentation phenotypes. Advances in this area are being facilitated by the application of modern methods of gene editing, genomics, computational analysis, and other approaches to non-traditional model organisms having interesting pigmentary phenotypes. Several topics worthy of future attention are outlined as well.
Topics: Animals; Biological Evolution; Gene Expression Regulation, Developmental; Phenotype; Pigmentation; Skin; Species Specificity; Zebrafish
PubMed: 33743392
DOI: 10.1016/j.gde.2021.02.006 -
Forensic Science International. Genetics Jan 2021Predicting appearance phenotypes from genotypes is relevant for various areas of human genetic research and applications such as genetic epidemiology, human history,...
Predicting appearance phenotypes from genotypes is relevant for various areas of human genetic research and applications such as genetic epidemiology, human history, anthropology, and particularly in forensics. Many appearance phenotypes, and thus their underlying genotypes, are highly correlated, with pigmentation traits serving as primary examples. However, all available genetic prediction models, including those for pigmentation traits currently used in forensic DNA phenotyping, ignore phenotype correlations. Here, we investigated the impact of appearance phenotype correlations on genetic appearance prediction in the exemplary case of three pigmentation traits. We used data for categorical eye, hair and skin colour as well as 41 DNA markers utilized in the recently established HIrisPlex-S system from 762 individuals with complete phenotype and genotype information. Based on these data, we performed genetic prediction modelling of eye, hair and skin colour via three different strategies, namely the established approach of predicting phenotypes solely based on genotypes while not considering phenotype correlations, and two novel approaches that considered phenotype correlations, either incorporating truly observed correlated phenotypes or DNA-predicted correlated phenotypes in addition to the DNA predictors. We found that using truly observed correlated pigmentation phenotypes as additional predictors increased the DNA-based prediction accuracies for almost all eye, hair and skin colour categories, with the largest increase for intermediate eye colour, brown hair colour, dark to black skin colour, and particularly for dark skin colour. Outcomes of dedicated computer simulations suggest that this prediction accuracy increase is due to the additional genetic information that is implicitly provided by the truly observed correlated pigmentation phenotypes used, yet not covered by the DNA predictors applied. In contrast, considering DNA-predicted correlated pigmentation phenotypes as additional predictors did not improve the performance of the genetic prediction of eye, hair and skin colour, which was in line with the results from our computer simulations. Hence, in practical applications of DNA-based appearance prediction where no phenotype knowledge is available, such as in forensic DNA phenotyping, it is not advised to use DNA-predicted correlated phenotypes as predictors in addition to the DNA predictors. In the very least, this is not recommended for the pigmentation traits and the established pigmentation DNA predictors tested here.
Topics: Computer Simulation; DNA; Eye Color; Female; Forensic Genetics; Genetic Markers; Genotype; Hair Color; Humans; Male; Models, Genetic; Phenotype; Polymorphism, Single Nucleotide; Skin Pigmentation
PubMed: 33070049
DOI: 10.1016/j.fsigen.2020.102395