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Journal of Phycology Feb 2016Various life cycle stages of cyst-producing dinoflagellates often appear differently colored under the microscope; gametes appear paler while zygotes are darker in...
Various life cycle stages of cyst-producing dinoflagellates often appear differently colored under the microscope; gametes appear paler while zygotes are darker in comparison to vegetative cells. To compare physiological and photochemical competency, the pigment composition of discrete life cycle stages was determined for the common resting cyst-producing dinoflagellate Scrippsiella lachrymosa. Vegetative cells had the highest cellular pigment content (25.2 ± 0.5 pg · cell(-1) ), whereas gamete pigment content was 22% lower. The pigment content of zygotes was 82% lower than vegetative cells, even though they appeared darker under the microscope. Zygotes of S. lachrymosa contained significantly higher cellular concentrations of β-carotene (0.65 ± 0.15 pg · cell(-1) ) than all other life stages. Photoprotective pigments and the de-epoxidation ratio of xanthophylls-cycle pigments in S. lachrymosa were significantly elevated in zygotes and cysts compared to other stages. This suggests a role for accessory pigments in combating intracellular oxidative stress during sexual reproduction or encystment. Resting cysts contained some pigments even though chloroplasts were not visible, suggesting that the brightly colored accumulation body contained photosynthetic pigments. The differences in pigmentation between life stages have implications for interpretation of pigment data from field samples when sampled during dinoflagellate blooms.
Topics: Chlorophyll; Dinoflagellida; Life Cycle Stages; Oxidative Stress; Photosynthesis; Pigmentation; Xanthophylls; Zygote; beta Carotene
PubMed: 26987089
DOI: 10.1111/jpy.12364 -
Journal of Animal Science Jul 2015Cancer of the eye in cattle with white faces occurs less frequently in cattle with pigmented eyelids. Corneoscleral pigmentation is related to eyelid pigmentation and...
Cancer of the eye in cattle with white faces occurs less frequently in cattle with pigmented eyelids. Corneoscleral pigmentation is related to eyelid pigmentation and occurrence of lesions that may precede cancer. Objectives of this study were to assess 1) variation in the proportion of eyelid and corneoscleral pigmentation in Hereford, Bos taurus, and Bos indicus crossbreds and 2) the occurrence of lesions with the presence of pigmentation in those areas. Hereford and Bos indicus crosses (Brahman or Nellore with Angus and Hereford and straightbred Brafords) and Bos taurus crosses (Angus-Hereford) were included in the study (n = 1,083). Eyelid pigmentation proportions were estimated by pixel quantification and were evaluated as total proportions and for upper and lower eyelids distinctly for each eye. Fixed effects included breed type, age categories, and sex of the animal. Lesion presence (1) or absence (0) was obtained by visual appraisal of image and was assumed to be binomially distributed. Eyelid pigmentation proportions (overall, upper, and lower eyelids) for Hereford ranged from 0.65 ± 0.03 to 0.68 ± 0.03 and were significantly lower than Bos indicus (range from 0.93 ± 0.02 to 0.95 ± 0.02) or Bos taurus (ranged from 0.88 ± 0.02 to 0.92 ± 0.02) crosses. Corneoscleral pigmentation in Hereford cows (0.17 ± 0.06) did not differ (P = 0.91) from Hereford calves and yearlings (0.16 ± 0.07). Bos indicus and Bos taurus crossbred cows had larger corneoscleral pigmentation (0.38 ± 0.05 and 0.48 ± 0.04 for left eyes and 0.37 ± 0.05 and 0.53 ± 0.04 for right eyes, respectively) than all calves (P < 0.001), and their corneoscleral pigmentations were greater than that of Hereford cows (P < 0.003). Bos indicus and Bos taurus cows had greater proportions of left eye corneoscleral pigmentation (0.38 ± 0.05 and 0.48 ± 0.04, respectively) than Hereford cows (0.17 ± 0.06) and all young animal breed types (P < 0.05). Right eye proportions differed for all cow groups (P < 0.05; 0.53 ± 0.04, 0.37 ± 0.05, and 0.17 ± 0.06). Among calves and yearlings, Hereford had a lower right eye corneoscleral pigmentation proportion (0.16 ± 0.07) than Bos taurus (P = 0.02). The lesion proportion for Hereford (0.08 ± 0.03) was significantly greater than that of either Bos indicus (0.01 ± 0.005) or Bos taurus (0.01 ± 0.003). Crossbreeding with Bos taurus or Bos indicus animals appears to increase eye pigmentation, which may help reduce the occurrence of cancer in eyes of cattle with white faces.
Topics: Animals; Cattle; Cornea; Crosses, Genetic; Eyelids; Female; Male; Pigments, Biological; Sclera; Skin Pigmentation
PubMed: 26440031
DOI: 10.2527/jas.2014-8786 -
Evolution; International Journal of... Dec 2018Developmental pathways play a major role in influencing the distribution of naturally occurring phenotypes. For example, pathway structure and regulation could make some...
Developmental pathways play a major role in influencing the distribution of naturally occurring phenotypes. For example, pathway structure and regulation could make some phenotypes inaccessible or restrict the routes through which phenotypes evolve. In this study, we examine floral anthocyanin pigments across the Solanaceae family and test whether patterns of phenotypic variation are consistent with predicted constraints based on the structure of the flavonoid biosynthetic pathway. We find that anthocyanin evolution occurs in a stepwise manner whereby transitions between the production of red mono hydroxylated pelargonidin pigments and blue trihydroxylated delphinidin pigments first passes through an intermediate step of producing purple dihydroxylated cyanidin pigments. Although the transitions between these three pigment types differ in frequency, we infer that these shifts are often reversible, suggesting that the functionality of the underlying biochemical pathway is generally conserved. Furthermore, our study finds that some pigment combinations are never observed, pointing to additional constraints on naturally occurring phenotypes. Overall, our findings provide insights into how the structure of an angiosperm-wide biochemical pathway has shaped macroevolutionary variation in floral pigmentation.
Topics: Biological Evolution; Flowers; Gene Expression Regulation, Plant; Markov Chains; Models, Genetic; Pigmentation; Solanaceae; Species Specificity; Stochastic Processes
PubMed: 30187462
DOI: 10.1111/evo.13589 -
Current Opinion in Plant Biology Feb 2019While the pathways that produce plant pigments have been well studied for decades, the use by plants of nanoscale structures to produce colour effects has only recently... (Review)
Review
While the pathways that produce plant pigments have been well studied for decades, the use by plants of nanoscale structures to produce colour effects has only recently begun to be studied. A variety of plants from across the plant kingdom have been shown to use different mechanism to generate structural colours in tissues as diverse as leaves, flowers and fruits. In this review we explore the cellular mechanisms by which these nanoscale structures are built and discuss the first insights that have been published into the genetic pathways underpinning these traits.
Topics: Cell Wall; Optical Phenomena; Pigmentation; Plant Cells; Plants
PubMed: 30399605
DOI: 10.1016/j.pbi.2018.10.002 -
Journal of the Royal Society, Interface Nov 2009Pigmentation of murine cardiac tricuspid valve leaflet is associated with melanocyte concentration, which affects its stiffness. Owing to its biological and viscoelastic...
Pigmentation of murine cardiac tricuspid valve leaflet is associated with melanocyte concentration, which affects its stiffness. Owing to its biological and viscoelastic nature, estimation of the in situ stiffness measurement becomes a challenging task. Therefore, quasi-static and nanodynamic mechanical analysis of the leaflets of the mouse tricuspid valve is performed in the current work. The mechanical properties along the leaflet vary with the degree of pigmentation. Pigmented regions of the valve leaflet that contain melanocytes displayed higher storage modulus (7-10 GPa) than non-pigmented areas (2.5-4 GPa). These results suggest that the presence of melanocytes affects the viscoelastic properties of the mouse atrioventricular valves and are important for their proper functioning in the organism.
Topics: Animals; Biomechanical Phenomena; Elasticity; Melanocytes; Mice; Pigmentation; Tricuspid Valve
PubMed: 19586956
DOI: 10.1098/rsif.2009.0174 -
Journal of Evolutionary Biology Dec 2018Pigments determine the appearance of organisms. However, pigment production can be associated with physiological constraints as in the case of pheomelanin, the...
Pigments determine the appearance of organisms. However, pigment production can be associated with physiological constraints as in the case of pheomelanin, the sulphurated form of melanin whose synthesis in melanocytes consumes cysteine and consequently reduces the availability of glutathione (GSH) to exert antioxidant protection. Pheomelanogenesis may thus increase the susceptibility to suffer chronic oxidative stress. I investigated the possibility that environmental lability in the expression of genes regulating pheomelanogenesis protects from oxidative stress, a situation in which GSH is most required. By broadcasting adult alarm calls, I manipulated the perception of predation risk, a natural source of oxidative stress, in free-living Eurasian nuthatch Sitta europaea nestlings developing pheomelanin-pigmented flank feathers. The manipulation affected the consumption of GSH that resulted from the expression of two genes (Slc7a11 and Slc45a2) influencing cysteine/GSH availability in cells, as these genes were down-regulated in the feather melanocytes of the nestlings with lowest intracellular antioxidant capacity (i.e. lowest GSH levels). Systemic oxidative damage increased with Slc7a11 expression in feather melanocytes, suggesting that the observed down-regulation was physiologically advantageous. The nestlings exposed to an increased perception of predation risk developed flank feathers of reduced colour intensity. These results indicate that perceived predation risk can determine the pigmentation phenotype by (probably epigenetic) effects on gene expression that protect from physiological constraints imposed by pheomelanin production.
Topics: Animals; Feathers; Gene Expression Regulation; Melanins; Passeriformes; Pigmentation; Pigments, Biological; Predatory Behavior; Vocalization, Animal
PubMed: 30256489
DOI: 10.1111/jeb.13379 -
Investigative Ophthalmology & Visual... Aug 1989Using a rabbit model we investigated the role of pigmentation of the ciliary body in obtaining ciliodestruction by neodymium-YAG transscleral cyclophotocoagulation.... (Comparative Study)
Comparative Study
Using a rabbit model we investigated the role of pigmentation of the ciliary body in obtaining ciliodestruction by neodymium-YAG transscleral cyclophotocoagulation. There was marked destruction of the ciliary body in pigmented rabbit eyes, but no histologic effect was observed in albino rabbit eyes. These findings suggest that pigmentation of the ciliary body is important for obtaining the desired response from neodymium-YAG transscleral cyclophotocoagulation in rabbit eyes by our technique. Further study is necessary to define the role of pigmentation in human eyes in this treatment modality.
Topics: Animals; Ciliary Body; Intraocular Pressure; Laser Therapy; Light Coagulation; Pigmentation; Rabbits; Sclera; Time Factors
PubMed: 2759796
DOI: No ID Found -
Cell Reports Aug 2023A previously undescribed mechanism underlying butterfly wing coloration patterns was discovered in two distantly related butterfly species, Siproeta stelenes and...
A previously undescribed mechanism underlying butterfly wing coloration patterns was discovered in two distantly related butterfly species, Siproeta stelenes and Philaethria diatonica. These butterflies have bright green wings, but the color pattern is not derived from solid pigments or nanostructures of the scales or from the color of the cuticular membrane but rather from a liquid retained in the wing membrane. Wing structure differs between the green and non-green areas. In the non-green region, the upper and lower cuticular membranes are attached to each other, whereas in the green region, we observed a space of 5-10 μm where green liquid is held and living cells are present. A pigment analysis and tracer experiment revealed that the color of the liquid is derived from hemolymph components, bilin and carotenoid pigments. This discovery broadens our understanding of the diverse ways in which butterfly wings obtain their coloration and patterns.
Topics: Animals; Pigmentation; Butterflies; Wings, Animal; Membranes; Nanostructures
PubMed: 37537843
DOI: 10.1016/j.celrep.2023.112917 -
Pigment Cell Research Feb 2007Although the various vertebrate classes, from fishes to mammals are each distinctive, they possess many common features making it important to understand their... (Review)
Review
Although the various vertebrate classes, from fishes to mammals are each distinctive, they possess many common features making it important to understand their comparative biology. One general feature that has long commanded interest is the integumental pigmentary system. Thus, much is known about particular pigment cells; however, the basis for some specific colors, such as blue, has escaped the scrutiny of the comparative approach. Regardless of Class, blue is almost always a structural color based upon incoherent or coherent scatter of blue wavelengths from the animal surface. The source of scatter may be intracellular or extra-cellular. A main intracellular scatterer is the surface of reflecting platelets of iridophores of lower vertebrates. Extra-cellular scatter is widespread and thought to occur from ordered dermal collagen arrays in primitive fishes, birds and mammals including humans. Among birds, feather structures provide major means for extra-cellular light scatter. There is only one known example of blue color deriving from a blue pigment found within a pigment cell. For amphibians, reptiles and birds, the scatter of blue wavelengths, together with the presence of yellow pigmentation, is fundamental for the expression of green coloration.
Topics: Animals; Color; Pigmentation; Vertebrates
PubMed: 17250544
DOI: 10.1111/j.1600-0749.2006.00360.x -
Pigment Cell Research Nov 1992
Review
Topics: Animals; Humans; Inflammation; Pigmentation
PubMed: 1292021
DOI: 10.1111/j.1600-0749.1992.tb00563.x