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Sample records for pigmentation pathway evolution

  1. Evolution of pigment synthesis pathways by gene and genome duplication in fish

    PubMed Central

    Braasch, Ingo; Schartl, Manfred; Volff, Jean-Nicolas

    2007-01-01

    Background Coloration and color patterning belong to the most diverse phenotypic traits in animals. Particularly, teleost fishes possess more pigment cell types than any other group of vertebrates. As the result of an ancient fish-specific genome duplication (FSGD), teleost genomes might contain more copies of genes involved in pigment cell development than tetrapods. No systematic genomic inventory allowing to test this hypothesis has been drawn up so far for pigmentation genes in fish, and almost nothing is known about the evolution of these genes in different fish lineages. Results Using a comparative genomic approach including phylogenetic reconstructions and synteny analyses, we have studied two major pigment synthesis pathways in teleost fish, the melanin and the pteridine pathways, with respect to different types of gene duplication. Genes encoding three of the four enzymes involved in the synthesis of melanin from tyrosine have been retained as duplicates after the FSGD. In the pteridine pathway, two cases of duplicated genes originating from the FSGD as well as several lineage-specific gene duplications were observed. In both pathways, genes encoding the rate-limiting enzymes, tyrosinase and GTP-cyclohydrolase I (GchI), have additional paralogs in teleosts compared to tetrapods, which have been generated by different modes of duplication. We have also observed a previously unrecognized diversity of gchI genes in vertebrates. In addition, we have found evidence for divergent resolution of duplicated pigmentation genes, i.e., differential gene loss in divergent teleost lineages, particularly in the tyrosinase gene family. Conclusion Mainly due to the FSGD, teleost fishes apparently have a greater repertoire of pigment synthesis genes than any other vertebrate group. Our results support an important role of the FSGD and other types of duplication in the evolution of pigmentation in fish. PMID:17498288

  2. Lineage-specific gene radiations underlie the evolution of novel betalain pigmentation in Caryophyllales

    PubMed Central

    Brockington, Samuel F; Yang, Ya; Gandia-Herrero, Fernando; Covshoff, Sarah; Hibberd, Julian M; Sage, Rowan F; Wong, Gane K S; Moore, Michael J; Smith, Stephen A

    2015-01-01

    Betalain pigments are unique to the Caryophyllales and structurally and biosynthetically distinct from anthocyanins. Two key enzymes within the betalain synthesis pathway have been identified: 4,5-dioxygenase (DODA) that catalyzes the formation of betalamic acid and CYP76AD1, a cytochrome P450 gene that catalyzes the formation of cyclo-DOPA. We performed phylogenetic analyses to reveal the evolutionary history of the DODA and CYP76AD1 lineages and in the context of an ancestral reconstruction of pigment states we explored the evolution of these genes in relation to the complex evolution of pigments in Caryophylalles. Duplications within the CYP76AD1 and DODA lineages arose just before the origin of betalain pigmentation in the core Caryophyllales. The duplications gave rise to DODA-α and CYP76AD1-α isoforms that appear specific to betalain synthesis. Both betalain-specific isoforms were then lost or downregulated in the anthocyanic Molluginaceae and Caryophyllaceae. Our findings suggest a single origin of the betalain synthesis pathway, with neofunctionalization following gene duplications in the CYP76AD1 and DODA lineages. Loss of DODA-α and CYP76AD1-α in anthocyanic taxa suggests that betalain pigmentation has been lost twice in Caryophyllales, and exclusion of betalain pigments from anthocyanic taxa is mediated through gene loss or downregulation. [Correction added after online publication 13 May 2015: in the last two paragraphs of the Summary the gene name CYP761A was changed to CYP76AD1.] PMID:25966996

  3. Lineage-specific gene radiations underlie the evolution of novel betalain pigmentation in Caryophyllales.

    PubMed

    Brockington, Samuel F; Yang, Ya; Gandia-Herrero, Fernando; Covshoff, Sarah; Hibberd, Julian M; Sage, Rowan F; Wong, Gane K S; Moore, Michael J; Smith, Stephen A

    2015-09-01

    Betalain pigments are unique to the Caryophyllales and structurally and biosynthetically distinct from anthocyanins. Two key enzymes within the betalain synthesis pathway have been identified: 4,5-dioxygenase (DODA) that catalyzes the formation of betalamic acid and CYP76AD1, a cytochrome P450 gene that catalyzes the formation of cyclo-DOPA. We performed phylogenetic analyses to reveal the evolutionary history of the DODA and CYP76AD1 lineages and in the context of an ancestral reconstruction of pigment states we explored the evolution of these genes in relation to the complex evolution of pigments in Caryophylalles. Duplications within the CYP76AD1 and DODA lineages arose just before the origin of betalain pigmentation in the core Caryophyllales. The duplications gave rise to DODA-α and CYP76AD1-α isoforms that appear specific to betalain synthesis. Both betalain-specific isoforms were then lost or downregulated in the anthocyanic Molluginaceae and Caryophyllaceae. Our findings suggest a single origin of the betalain synthesis pathway, with neofunctionalization following gene duplications in the CYP76AD1 and DODA lineages. Loss of DODA-α and CYP76AD1-α in anthocyanic taxa suggests that betalain pigmentation has been lost twice in Caryophyllales, and exclusion of betalain pigments from anthocyanic taxa is mediated through gene loss or downregulation. [Correction added after online publication 13 May 2015: in the last two paragraphs of the Summary the gene name CYP761A was changed to CYP76AD1.].

  4. Not just black and white: pigment pattern development and evolution in vertebrates

    PubMed Central

    Mills, Margaret G.; Patterson, Larissa B.

    2009-01-01

    Animals display diverse colors and patterns that vary within and between species. Similar phenotypes appear in both closely related and widely divergent taxa. Pigment patterns thus provide an opportunity to explore how development is altered to produce differences in form and whether similar phenotypes share a common genetic basis. Understanding the development and evolution of pigment patterns requires knowledge of the cellular interactions and signaling pathways that produce those patterns. These complex traits provide unparalleled opportunities for integrating studies from ecology and behavior to molecular biology and biophysics. PMID:19073271

  5. Evolution of geographic atrophy of the retinal pigment epithelium.

    PubMed

    Sarks, J P; Sarks, S H; Killingsworth, M C

    1988-01-01

    The aim of this study was to trace the evolution of geographic atrophy (GA) by clinical documentation and by clinico-morphological correlation in representative eyes. Geographic atrophy commonly commenced within a parafoveal band of incipient atrophy of varying width, characterised by semisolid drusen and a microreticular pigment pattern. Progression of atrophy mostly skirted fixation and visual acuity was a poor guide to the functional impact, an estimate of the percentage of fovea involved proving a more useful clinical parameter. The rate of progression slowed once GA had involved all the retina affected by incipient atrophy and the risk of choroidal neovascularization appeared to decline. An earlier histological classification of the evolution of GA is revised according to the ultrastructural findings. Membranous debris was not previously recognised and its contribution to the findings in incipient atrophy and to dot-like drusen is described.

  6. Pigment-acceptor-catalyst triads for photochemical hydrogen evolution.

    PubMed

    Kitamoto, Kyoji; Sakai, Ken

    2014-04-25

    In order to solve the problems of global warming and shortage of fossil fuels, researchers have been endeavoring to achieve artificial photosynthesis: splitting water into H2 and O2 under solar light illumination. Our group has recently invented a unique system that drives photoinduced water reduction through "Z-scheme" photosynthetic pathways. Nevertheless, that system still suffered from a low turnover number (TON) of the photocatalytic cycle (TON=4.1). We have now found and describe herein a new methodology to make significant improvements in the TON, up to around TON=14-27. For the new model systems reported herein, the quantum efficiency of the second photoinduced step in the Z-scheme photosynthesis is dramatically improved by introducing multiviologen tethers to temporarily collect the high-energy electron generated in the first photoinduced step. These are unique examples of "pigment-acceptor-catalyst triads", which demonstrate a new effective type of artificial photosynthesis.

  7. Pigment cell interactions and differential xanthophore recruitment underlying zebrafish stripe reiteration and Danio pattern evolution.

    PubMed

    Patterson, Larissa B; Bain, Emily J; Parichy, David M

    2014-11-06

    Fishes have diverse pigment patterns, yet mechanisms of pattern evolution remain poorly understood. In zebrafish, Danio rerio, pigment-cell autonomous interactions generate dark stripes of melanophores that alternate with light interstripes of xanthophores and iridophores. Here, we identify mechanisms underlying the evolution of a uniform pattern in D. albolineatus in which all three pigment cell classes are intermingled. We show that in this species xanthophores differentiate precociously over a wider area, and that cis regulatory evolution has increased expression of xanthogenic Colony Stimulating Factor-1 (Csf1). Expressing Csf1 similarly in D. rerio has cascading effects, driving the intermingling of all three pigment cell classes and resulting in the loss of stripes, as in D. albolineatus. Our results identify novel mechanisms of pattern development and illustrate how pattern diversity can be generated when a core network of pigment-cell autonomous interactions is coupled with changes in pigment cell differentiation.

  8. Networks and pathways in pigmentation, health, and disease.

    PubMed

    Baxter, Laura L; Loftus, Stacie K; Pavan, William J

    2009-01-01

    Extensive studies of the biology of the pigment-producing cell (melanocyte) have resulted in a wealth of knowledge regarding the genetics and developmental mechanisms governing skin and hair pigmentation. The ease of identification of altered pigment phenotypes, particularly in mouse coat color mutants, facilitated early use of the pigmentary system in mammalian genetics and development. In addition to the large collection of developmental genetics data, melanocytes are of interest because their malignancy results in melanoma, a highly aggressive and frequently fatal cancer that is increasing in Caucasian populations worldwide. The genetic programs regulating melanocyte development, function, and malignancy are highly complex and only partially understood. Current research in melanocyte development and pigmentation is revealing new genes important in these processes and additional functions for previously known individual components. A detailed understanding of all the components involved in melanocyte development and function, including interactions with neighboring cells and response to environmental stimuli, will be necessary to fully comprehend this complex system. The inherent characteristics of pigmentation biology as well as the resources available to researchers in the pigment cell community make melanocytes an ideal cell type for analysis using systems biology approaches. In this review, the study of melanocyte development and pigmentation is considered as a candidate for systems biology-based analyses.

  9. New biosynthetic pathway for pink pigments from uncultured oceanic viruses.

    PubMed

    Ledermann, Benjamin; Béjà, Oded; Frankenberg-Dinkel, Nicole

    2016-12-01

    The pink open-chain tetrapyrrole pigment phycoerythrobilin (PEB) is employed by marine cyanobacteria, red algae and cryptophytes as a light-harvesting chromophore in phycobiliproteins. Genes encoding biosynthesis proteins for PEB have also been discovered in cyanophages, viruses that infect cyanobacteria, and mimic host pigment biosynthesis with the exception of PebS which combines the enzymatic activities of two host enzymes. In this study, we have identified novel members of the PEB biosynthetic enzyme families, heme oxygenases and ferredoxin-dependent bilin reductases. Encoding genes were found in metagenomic datasets and could be traced back to bacteriophage but not cyanophage origin. While the heme oxygenase exhibited standard activity, a new bilin reductase with highest homology to the teal pigment producing enzyme PcyA revealed PEB biosynthetic activity. Although PcyX possesses PebS-like activity both enzymes share only 9% sequence identity and likely catalyze the reaction via two independent mechanisms. Our data point towards the presence of phycobilin biosynthetic genes in phages that probably infect alphaproteobacteria and, therefore, further support a role of phycobilins outside oxygenic phototrophs.

  10. Origins of adult pigmentation: diversity in pigment stem cell lineages and implications for pattern evolution

    PubMed Central

    Spiewak, Jessica E.

    2014-01-01

    Summary Teleosts comprise about half of all vertebrate species and exhibit an extraordinary diversity of adult pigment patterns that function in shoaling, camouflage and mate choice and have played important roles in speciation. Here, we review recent studies that have identified several distinct neural crest lineages, with distinct genetic requirements, that give rise to adult pigment cells in fishes. These lineages include post-embryonic, peripheral nerve associated stem cells that generate black melanophores and iridescent iridophores, cells derived directly from embryonic neural crest cells that generate yellow-orange xanthophores, and bipotent stem cells that generate both melanophores and xanthophores. This complexity in adult chromatophore lineages has implications for our understanding of adult traits, melanoma, and the evolutionary diversification of pigment cell lineages and patterns. PMID:25421288

  11. Origins of adult pigmentation: diversity in pigment stem cell lineages and implications for pattern evolution.

    PubMed

    Parichy, David M; Spiewak, Jessica E

    2015-01-01

    Teleosts comprise about half of all vertebrate species and exhibit an extraordinary diversity of adult pigment patterns that function in shoaling, camouflage, and mate choice and have played important roles in speciation. Here, we review studies that have identified several distinct neural crest lineages, with distinct genetic requirements, that give rise to adult pigment cells in fishes. These lineages include post-embryonic, peripheral nerve-associated stem cells that generate black melanophores and iridescent iridophores, cells derived directly from embryonic neural crest cells that generate yellow-orange xanthophores, and bipotent stem cells that generate both melanophores and xanthophores. This complexity in adult chromatophore lineages has implications for our understanding of adult traits, melanoma, and the evolutionary diversification of pigment cell lineages and patterns.

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

    PubMed

    Osborne, Daniel L; Hames, Raymond

    2014-01-01

    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.

  13. The contribution of the melanin pathway to overall body pigmentation during ontogenesis of Periplaneta americana.

    PubMed

    Lemonds, Thomas R; Liu, Jin; Popadić, Aleksandar

    2016-08-01

    The most prominent colors observed in insects are black or brown, whose production is attributed to the melanin pathway. At present, though, the contribution of this pathway to overall body pigmentation throughout ontogenesis is still lacking. To address this question we examined the roles of 2 key melanin genes (TH and DDC), in embryonic and postembryonic development of the American cockroach, Periplaneta americana. Our results show that the melanin pathway does not contribute to the light brown coloration observed in the first nymphs. However, the dark brown coloration in mid nymphs and adults is produced solely from the melanin pathway. In addition, the DDC RNAi results reveal that it is dopamine melanin, not DOPA melanin, acts as the main contributor in this process. Overall, present study provides a new insight into insect pigmentation suggesting that genetic mechanisms of coloration can change during ontogenesis. Future studies of additional basal insect lineages will be required to assess in more details the generality of this phenomenon.

  14. Pigmentation, pleiotropy, and genetic pathways in humans and mice

    SciTech Connect

    Barsh, G.S.

    1995-10-01

    Some of the most striking polymorphisms in human populations affect the color of our eyes, hair, or skin. Despite some simple lessons from high school biology (blue eyes are recessive; brown are dominant), the genetic basis of such phenotypic variability has, for the most part, eluded Mendelian description. A logical place to search for the keys to understanding common variation in human pigmentation are genes in which defects cause uncommon conditions such as albinism or piebaldism. The area under this lamppost has recently gotten larger, with two articles, one in this issue of the Journal, that describe the map position for Hermansky-Pudlak syndrome (HPS) and with the recent cloning of a gene that causes X-linked ocular albinism (OA1). In addition, a series of three recent articles in Cell demonstrate (1) that defects in the gene encoding the endothelin B (ET{sub B}) receptor cause hypopigmentation and Hirschsprung disease in a Mennonite population and the mouse mutation piebald(s) and (2) that a defect in the edn3 gene, which encodes one of the ligands for the ET{sub B} receptor, causes the lethal spotting (ls) mouse mutation. 47 refs., 1 fig.

  15. The Evolution of the Wnt Pathway

    PubMed Central

    Holstein, Thomas W.

    2012-01-01

    Wnt genes are important regulators of embryogenesis and cell differentiation in vertebrates and insects. New data revealed by comparative genomics have now shown that members of the Wnt signaling pathway can be found in all clades of metazoans, but not in fungi, plants, or unicellular eukaryotes. This article focuses on new data from recent genomic analyses of several basal metazoan organisms, providing evidence that the Wnt pathway was a primordial signaling pathway during evolution. The formation of a Wnt signaling center at the site of gastrulation was instrumental for the formation of a primary, anterior–posterior body axis, which can be traced throughout animal evolution. PMID:22751150

  16. Brain evolution by brain pathway duplication

    PubMed Central

    Chakraborty, Mukta; Jarvis, Erich D.

    2015-01-01

    Understanding the mechanisms of evolution of brain pathways for complex behaviours is still in its infancy. Making further advances requires a deeper understanding of brain homologies, novelties and analogies. It also requires an understanding of how adaptive genetic modifications lead to restructuring of the brain. Recent advances in genomic and molecular biology techniques applied to brain research have provided exciting insights into how complex behaviours are shaped by selection of novel brain pathways and functions of the nervous system. Here, we review and further develop some insights to a new hypothesis on one mechanism that may contribute to nervous system evolution, in particular by brain pathway duplication. Like gene duplication, we propose that whole brain pathways can duplicate and the duplicated pathway diverge to take on new functions. We suggest that one mechanism of brain pathway duplication could be through gene duplication, although other mechanisms are possible. We focus on brain pathways for vocal learning and spoken language in song-learning birds and humans as example systems. This view presents a new framework for future research in our understanding of brain evolution and novel behavioural traits. PMID:26554045

  17. Diversifying Carotenoid Biosynthetic Pathways by Directed Evolution

    PubMed Central

    Umeno, Daisuke; Tobias, Alexander V.; Arnold, Frances H.

    2005-01-01

    Microorganisms and plants synthesize a diverse array of natural products, many of which have proven indispensable to human health and well-being. Although many thousands of these have been characterized, the space of possible natural products—those that could be made biosynthetically—remains largely unexplored. For decades, this space has largely been the domain of chemists, who have synthesized scores of natural product analogs and have found many with improved or novel functions. New natural products have also been made in recombinant organisms, via engineered biosynthetic pathways. Recently, methods inspired by natural evolution have begun to be applied to the search for new natural products. These methods force pathways to evolve in convenient laboratory organisms, where the products of new pathways can be identified and characterized in high-throughput screening programs. Carotenoid biosynthetic pathways have served as a convenient experimental system with which to demonstrate these ideas. Researchers have mixed, matched, and mutated carotenoid biosynthetic enzymes and screened libraries of these “evolved” pathways for the emergence of new carotenoid products. This has led to dozens of new pathway products not previously known to be made by the assembled enzymes. These new products include whole families of carotenoids built from backbones not found in nature. This review details the strategies and specific methods that have been employed to generate new carotenoid biosynthetic pathways in the laboratory. The potential application of laboratory evolution to other biosynthetic pathways is also discussed. PMID:15755953

  18. Habitat-specific pigmentation in a freshwater isopod: adaptive evolution over a small spatiotemporal scale.

    PubMed

    Hargeby, Anders; Johansson, Jonas; Ahnesjö, Jonas

    2004-01-01

    Pigmentation in the freshwater isopod Asellus aquaticus (Crustacea) differed between habitats in two Swedish lakes. In both lakes, isopods had lighter pigmentation in stands of submerged vegetation, consisting of stoneworts (Chara spp.), than in nearby stands of reed (Phragmites australis). Experimental crossings of light and dark isopods in a common environment showed that pigmentation had a genetic basis and that genetic variance was additive. Environmental effects of diet or chromatophore adjustment to the background had minor influence on pigmentation, as shown by laboratory rearing of isopods on stonewort or reed substrates, as well as analyses of stable isotope ratios for isopods collected in the field. In both study lakes, the average phenotype became lighter with time (across generations) in recently established stonewort stands. Taken together, these results indicate that altered phenotype pigmentation result from evolutionary responses to local differences in natural selection. Based on the assumption of two generations per year, the evolutionary rate of change in pigmentation was 0.08 standard deviations per generation (haldanes) over 20 generations in one lake and 0.22 haldanes over two generations in the other lake. This genetic change occurred during an episode of population growth in a novel habitat, a situation known to promote adaptive evolution. In addition, stonewort stands constitute large and persistent patches, characteristics that tend to preserve local adaptations produced by natural selection. Results from studies on selective forces behind the adaptive divergence suggest that selective predation from visually oriented predators is a possible selective agent. We found no indications of phenotype-specific movements between habitats. Mating within stonewort stands was random with respect to pigmentation, but on a whole-lake scale it is likely that mating is assortative, as a result of local differences in phenotype distribution.

  19. Evolution-guided optimization of biosynthetic pathways.

    PubMed

    Raman, Srivatsan; Rogers, Jameson K; Taylor, Noah D; Church, George M

    2014-12-16

    Engineering biosynthetic pathways for chemical production requires extensive optimization of the host cellular metabolic machinery. Because it is challenging to specify a priori an optimal design, metabolic engineers often need to construct and evaluate a large number of variants of the pathway. We report a general strategy that combines targeted genome-wide mutagenesis to generate pathway variants with evolution to enrich for rare high producers. We convert the intracellular presence of the target chemical into a fitness advantage for the cell by using a sensor domain responsive to the chemical to control a reporter gene necessary for survival under selective conditions. Because artificial selection tends to amplify unproductive cheaters, we devised a negative selection scheme to eliminate cheaters while preserving library diversity. This scheme allows us to perform multiple rounds of evolution (addressing ∼10(9) cells per round) with minimal carryover of cheaters after each round. Based on candidate genes identified by flux balance analysis, we used targeted genome-wide mutagenesis to vary the expression of pathway genes involved in the production of naringenin and glucaric acid. Through up to four rounds of evolution, we increased production of naringenin and glucaric acid by 36- and 22-fold, respectively. Naringenin production (61 mg/L) from glucose was more than double the previous highest titer reported. Whole-genome sequencing of evolved strains revealed additional untargeted mutations that likely benefit production, suggesting new routes for optimization.

  20. Origin and evolution of metabolic pathways

    NASA Astrophysics Data System (ADS)

    Fani, Renato; Fondi, Marco

    2009-03-01

    The emergence and evolution of metabolic pathways represented a crucial step in molecular and cellular evolution. In fact, the exhaustion of the prebiotic supply of amino acids and other compounds that were likely present in the ancestral environment, imposed an important selective pressure, favoring those primordial heterotrophic cells which became capable of synthesizing those molecules. Thus, the emergence of metabolic pathways allowed primitive organisms to become increasingly less-dependent on exogenous sources of organic compounds. Comparative analyses of genes and genomes from organisms belonging to Archaea, Bacteria and Eukarya revealed that, during evolution, different forces and molecular mechanisms might have driven the shaping of genomes and the arisal of new metabolic abilities. Among these gene elongations, gene and operon duplications undoubtedly played a major role since they can lead to the (immediate) appearance of new genetic material that, in turn, might undergo evolutionary divergence giving rise to new genes coding for new metabolic abilities. Gene duplication has been invoked in the different schemes proposed to explain why and how the extant metabolic pathways have arisen and shaped. Both the analysis of completely sequenced genomes and directed evolution experiments strongly support one of them, i.e. the patchwork hypothesis, according to which metabolic pathways have been assembled through the recruitment of primitive enzymes that could react with a wide range of chemically related substrates. However, the analysis of the structure and organization of genes belonging to ancient metabolic pathways, such as histidine biosynthesis and nitrogen fixation, suggested that other different hypothesis, i.e. the retrograde hypothesis or the semi-enzymatic theory, may account for the arisal of some metabolic routes.

  1. The evolution of plant virus transmission pathways.

    PubMed

    Hamelin, Frédéric M; Allen, Linda J S; Prendeville, Holly R; Hajimorad, M Reza; Jeger, Michael J

    2016-05-07

    The evolution of plant virus transmission pathways is studied through transmission via seed, pollen, or a vector. We address the questions: under what circumstances does vector transmission make pollen transmission redundant? Can evolution lead to the coexistence of multiple virus transmission pathways? We restrict the analysis to an annual plant population in which reproduction through seed is obligatory. A semi-discrete model with pollen, seed, and vector transmission is formulated to investigate these questions. We assume vector and pollen transmission rates are frequency-dependent and density-dependent, respectively. An ecological stability analysis is performed for the semi-discrete model and used to inform an evolutionary study of trade-offs between pollen and seed versus vector transmission. Evolutionary dynamics critically depend on the shape of the trade-off functions. Assuming a trade-off between pollen and vector transmission, evolution either leads to an evolutionarily stable mix of pollen and vector transmission (concave trade-off) or there is evolutionary bi-stability (convex trade-off); the presence of pollen transmission may prevent evolution of vector transmission. Considering a trade-off between seed and vector transmission, evolutionary branching and the subsequent coexistence of pollen-borne and vector-borne strains is possible. This study contributes to the theory behind the diversity of plant-virus transmission patterns observed in nature.

  2. Evolution and spectral tuning of visual pigments in birds and mammals

    PubMed Central

    Hunt, David M.; Carvalho, Livia S.; Cowing, Jill A.; Davies, Wayne L.

    2009-01-01

    Variation in the types and spectral characteristics of visual pigments is a common mechanism for the adaptation of the vertebrate visual system to prevailing light conditions. The extent of this diversity in mammals and birds is discussed in detail in this review, alongside an in-depth consideration of the molecular changes involved. In mammals, a nocturnal stage in early evolution is thought to underlie the reduction in the number of classes of cone visual pigment genes from four to only two, with the secondary loss of one of these genes in many monochromatic nocturnal and marine species. The trichromacy seen in many primates arises from either a polymorphism or duplication of one of these genes. In contrast, birds have retained the four ancestral cone visual pigment genes, with a generally conserved expression in either single or double cone classes. The loss of sensitivity to ultraviolet (UV) irradiation is a feature of both mammalian and avian visual evolution, with UV sensitivity retained among mammals by only a subset of rodents and marsupials. Where it is found in birds, it is not ancestral but newly acquired. PMID:19720655

  3. Positive selection of a duplicated UV-sensitive visual pigment coincides with wing pigment evolution in Heliconius butterflies

    PubMed Central

    Briscoe, Adriana D.; Bybee, Seth M.; Bernard, Gary D.; Yuan, Furong; Sison-Mangus, Marilou P.; Reed, Robert D.; Warren, Andrew D.; Llorente-Bousquets, Jorge; Chiao, Chuan-Chin

    2010-01-01

    The butterfly Heliconius erato can see from the UV to the red part of the light spectrum with color vision proven from 440 to 640 nm. Its eye is known to contain three visual pigments, rhodopsins, produced by an 11-cis-3-hydroxyretinal chromophore together with long wavelength (LWRh), blue (BRh) and UV (UVRh1) opsins. We now find that H. erato has a second UV opsin mRNA (UVRh2)—a previously undescribed duplication of this gene among Lepidoptera. To investigate its evolutionary origin, we screened eye cDNAs from 14 butterfly species in the subfamily Heliconiinae and found both copies only among Heliconius. Phylogeny-based tests of selection indicate positive selection of UVRh2 following duplication, and some of the positively selected sites correspond to vertebrate visual pigment spectral tuning residues. Epi-microspectrophotometry reveals two UV-absorbing rhodopsins in the H. erato eye with λmax = 355 nm and 398 nm. Along with the additional UV opsin, Heliconius have also evolved 3-hydroxy-DL-kynurenine (3-OHK)-based yellow wing pigments not found in close relatives. Visual models of how butterflies perceive wing color variation indicate this has resulted in an expansion of the number of distinguishable yellow colors on Heliconius wings. Functional diversification of the UV-sensitive visual pigments may help explain why the yellow wing pigments of Heliconius are so colorful in the UV range compared to the yellow pigments of close relatives lacking the UV opsin duplicate. PMID:20133601

  4. SWS2 visual pigment evolution as a test of historically contingent patterns of plumage color evolution in Warblers

    PubMed Central

    Bloch, Natasha I.; Morrow, James M.; Chang, Belinda S.W.; Price, Trevor D.

    2014-01-01

    Distantly related clades that occupy similar environments may differ due to the lasting imprint of their ancestors – historical contingency. The New World warblers (Parulidae) and Old World warblers (Phylloscopidae) are ecologically similar clades that differ strikingly in plumage coloration. We studied genetic and functional evolution of the short-wavelength sensitive visual pigments (SWS2 and SWS1) to ask if altered color perception could contribute to the plumage color differences between clades. We show SWS2 is short-wavelength shifted in birds that occupy open environments, such as finches, compared to those in closed environments, including warblers. Phylogenetic reconstructions indicate New World warblers were derived from a finch-like form that colonized from the Old World 15-20Ma. During this process the SWS2 gene accumulated 6 substitutions in branches leading to New World warblers, inviting the hypothesis that passage through a finch-like ancestor resulted in SWS2 evolution. In fact, we show spectral tuning remained similar across warblers as well as the finch ancestor. Results reject the hypothesis of historical contingency based on opsin spectral tuning, but point to evolution of other aspects of visual pigment function. Using the approach outlined here, historical contingency becomes a generally testable theory in systems where genotype and phenotype can be connected. PMID:25496318

  5. SWS2 visual pigment evolution as a test of historically contingent patterns of plumage color evolution in warblers.

    PubMed

    Bloch, Natasha I; Morrow, James M; Chang, Belinda S W; Price, Trevor D

    2015-02-01

    Distantly related clades that occupy similar environments may differ due to the lasting imprint of their ancestors-historical contingency. The New World warblers (Parulidae) and Old World warblers (Phylloscopidae) are ecologically similar clades that differ strikingly in plumage coloration. We studied genetic and functional evolution of the short-wavelength-sensitive visual pigments (SWS2 and SWS1) to ask if altered color perception could contribute to the plumage color differences between clades. We show SWS2 is short-wavelength shifted in birds that occupy open environments, such as finches, compared to those in closed environments, including warblers. Phylogenetic reconstructions indicate New World warblers were derived from a finch-like form that colonized from the Old World 15-20 Ma. During this process, the SWS2 gene accumulated six substitutions in branches leading to New World warblers, inviting the hypothesis that passage through a finch-like ancestor resulted in SWS2 evolution. In fact, we show spectral tuning remained similar across warblers as well as the finch ancestor. Results reject the hypothesis of historical contingency based on opsin spectral tuning, but point to evolution of other aspects of visual pigment function. Using the approach outlined here, historical contingency becomes a generally testable theory in systems where genotype and phenotype can be connected.

  6. The cone visual pigments of an Australian marsupial, the tammar wallaby (Macropus eugenii): sequence, spectral tuning, and evolution.

    PubMed

    Deeb, Samir S; Wakefield, Matthew J; Tada, Takashi; Marotte, Lauren; Yokoyama, Shozo; Marshall Graves, Jenny A

    2003-10-01

    Studies on marsupial color vision have been limited to very few species. There is evidence from behavioral, electroretinographic (ERG), and microspectrophotometric (MSP) measurements for the existence of both dichromatic and trichromatic color vision. No studies have yet investigated the molecular mechanisms of spectral tuning in the visual pigments of marsupials. Our study is the first to determine the mRNA sequence, infer the amino acid sequence, and determine, by in vitro expression, the spectra of the cone opsins of a marsupial, the tammar wallaby (Macropus eugenii). This yielded some information on mechanisms and evolution of spectral tuning of these pigments. The tammar wallaby retina contains only short-wavelength sensitive (SWS) and middle-wavelength sensitive (MWS) pigment mRNAs. This predicts dichromatic color vision, which is consistent with conclusions from previous behavioral studies ( Hemmi 1999). We found that the wallaby has a SWS1 class pigment of 346 amino acids. Sequence comparison with eutherian SWS pigments predicts that this SWS1 pigment absorbs maximally (lambdamax) at 424 nm and, therefore, is a blue rather than a UV pigment. This (lambdamax) is close to that of the in vitro-expressed wallaby SWS pigment (lambdamax of 420 +/- 2 nm) and to that determined behaviorally (420 nm). The difference from the mouse UV pigment (lambdamax of 359 nm) is largely accounted for by the F86Y substitution, in agreement with in vitro results comparing a variety of other SWS pigments. This suggests that spectral tuning employing F86Y substitution most likely arose independently in the marsupials and ungulates as a result of convergent evolution. An apparently different mechanism of spectral tuning of the SWS1 pigments, involving five amino acid positions, evolved in primates. The wallaby MWS pigment has 363 amino acids. Species comparisons at positions critical to spectral tuning predict a lambdamax near 530 nm, which is close to that of the in vitro

  7. Basis for the gain and subsequent dilution of epidermal pigmentation during human evolution: The barrier and metabolic conservation hypotheses revisited.

    PubMed

    Elias, Peter M; Williams, Mary L

    2016-10-01

    The evolution of human skin pigmentation must address both the initial evolution of intense epidermal pigmentation in hominins, and its subsequent dilution in modern humans. While many authorities believe that epidermal pigmentation evolved to protect against either ultraviolet B (UV-B) irradiation-induced mutagenesis or folic acid photolysis, we hypothesize that pigmentation augmented the epidermal barriers by shifting the UV-B dose-response curve from toxic to beneficial. Whereas erythemogenic UV-B doses produce apoptosis and cell death, suberythemogenic doses benefit permeability and antimicrobial function. Heavily melanized melanocytes acidify the outer epidermis and emit paracrine signals that augment barrier competence. Modern humans, residing in the cooler, wetter climes of south-central Europe and Asia, initially retained substantial pigmentation. While their outdoor lifestyles still permitted sufficient cutaneous vitamin D3 (VD3) synthesis, their marginal nutritional status, coupled with cold-induced caloric needs, selected for moderate pigment reductions that diverted limited nutritional resources towards more urgent priorities (=metabolic conservation). The further pigment-dilution that evolved as humans reached north-central Europe (i.e., northern France, Germany), likely facilitated cutaneous VD3 synthesis, while also supporting ongoing, nutritional requirements. But at still higher European latitudes where little UV-B breaches the atmosphere (i.e., present-day UK, Scandinavia, Baltic States), pigment dilution alone could not suffice. There, other nonpigment-related mutations evolved to facilitate VD3 production; for example, in the epidermal protein, filaggrin, resulting in reduced levels of its distal metabolite, trans-urocanic acid, a potent UV-B chromophore. Thus, changes in human pigmentation reflect a complex interplay between latitude, climate, diet, lifestyle, and shifting metabolic priorities.

  8. Discovery and characterization of a conserved pigment dispersing factor-like neuropeptide pathway in Caenorhabditis elegans.

    PubMed

    Janssen, Tom; Husson, Steven J; Meelkop, Ellen; Temmerman, Liesbet; Lindemans, Marleen; Verstraelen, Karen; Rademakers, Suzanne; Mertens, Inge; Nitabach, Michael; Jansen, Gert; Schoofs, Liliane

    2009-10-01

    The neuropeptides pigment dispersing factor (PDF) and vasoactive intestinal peptide (VIP) are known as key players in the circadian clock system of insects and mammals, respectively. In this study, we report the discovery and characterization of a widely conserved PDF-like neuropeptide precursor pathway in nematodes. Using a combinatorial approach of biochemistry and peptidomics, we have biochemically isolated, identified and characterized three PDF-like neuropeptides in the free-living nematode Caenorhabditis elegans. The two PDF encoding genes, which were designated pdf-1 and pdf-2, display a very strong conservation within the phylum of nematodes. Many of the PDF expressing cells in C. elegans play a role in the control of locomotion and the integration of environmental stimuli, among which light. Our real-time PCR analysis indicates that both PDF genes are consistently expressed during the day and do not affect each other's expression. The transcription of both PDF genes seems to be regulated by atf-2 and ces-2, which encode bZIP transcription factors homologous to Drosophila vrille and par domain protein 1 (Pdp1epsilon), respectively. Together, our data suggest that the PDF neuropeptide pathway, which seems to be conserved throughout the protostomian evolutionary lineage, might be more complex than previously assumed.

  9. Out of the blue: adaptive visual pigment evolution accompanies Amazon invasion.

    PubMed

    Van Nynatten, Alexander; Bloom, Devin; Chang, Belinda S W; Lovejoy, Nathan R

    2015-07-01

    Incursions of marine water into South America during the Miocene prompted colonization of freshwater habitats by ancestrally marine species and present a unique opportunity to study the molecular evolution of adaptations to varying environments. Freshwater and marine environments are distinct in both spectra and average intensities of available light. Here, we investigate the molecular evolution of rhodopsin, the photosensitive pigment in the eye that activates in response to light, in a clade of South American freshwater anchovies derived from a marine ancestral lineage. Using likelihood-based comparative sequence analyses, we found evidence for positive selection in the rhodopsin of freshwater anchovy lineages at sites known to be important for aspects of rhodopsin function such as spectral tuning. No evidence was found for positive selection in marine lineages, nor in three other genes not involved in vision. Our results suggest that an increased rate of rhodopsin evolution was driven by diversification into freshwater habitats, thereby constituting a rare example of molecular evolution mirroring large-scale palaeogeographic events.

  10. Molecular diversity, metabolic transformation, and evolution of carotenoid feather pigments in cotingas (Aves: Cotingidae).

    PubMed

    Prum, Richard O; LaFountain, Amy M; Berro, Julien; Stoddard, Mary Caswell; Frank, Harry A

    2012-12-01

    Carotenoid pigments were extracted from 29 feather patches from 25 species of cotingas (Cotingidae) representing all lineages of the family with carotenoid plumage coloration. Using high-performance liquid chromatography (HPLC), mass spectrometry, chemical analysis, and ¹H-NMR, 16 different carotenoid molecules were documented in the plumages of the cotinga family. These included common dietary xanthophylls (lutein and zeaxanthin), canary xanthophylls A and B, four well known and broadly distributed avian ketocarotenoids (canthaxanthin, astaxanthin, α-doradexanthin, and adonixanthin), rhodoxanthin, and seven 4-methoxy-ketocarotenoids. Methoxy-ketocarotenoids were found in 12 species within seven cotinga genera, including a new, previously undescribed molecule isolated from the Andean Cock-of-the-Rock Rupicola peruviana, 3'-hydroxy-3-methoxy-β,β-carotene-4-one, which we name rupicolin. The diversity of cotinga plumage carotenoid pigments is hypothesized to be derived via four metabolic pathways from lutein, zeaxanthin, β-cryptoxanthin, and β-carotene. All metabolic transformations within the four pathways can be described by six or seven different enzymatic reactions. Three of these reactions are shared among three precursor pathways and are responsible for eight different metabolically derived carotenoid molecules. The function of cotinga plumage carotenoid diversity was analyzed with reflectance spectrophotometry of plumage patches and a tetrahedral model of avian color visual perception. The evolutionary history of the origin of this diversity is analyzed phylogenetically. The color space analyses document that the evolutionarily derived metabolic modifications of dietary xanthophylls have resulted in the creation of distinctive orange-red and purple visual colors.

  11. Pigmented anatomy in Carboniferous cyclostomes and the evolution of the vertebrate eye

    PubMed Central

    Gabbott, Sarah E.; Sansom, Robert S.; Vinther, Jakob; Dolocan, Andrei; Purnell, Mark A.

    2016-01-01

    The success of vertebrates is linked to the evolution of a camera-style eye and sophisticated visual system. In the absence of useful data from fossils, scenarios for evolutionary assembly of the vertebrate eye have been based necessarily on evidence from development, molecular genetics and comparative anatomy in living vertebrates. Unfortunately, steps in the transition from a light-sensitive ‘eye spot’ in invertebrate chordates to an image-forming camera-style eye in jawed vertebrates are constrained only by hagfish and lampreys (cyclostomes), which are interpreted to reflect either an intermediate or degenerate condition. Here, we report—based on evidence of size, shape, preservation mode and localized occurrence—the presence of melanosomes (pigment-bearing organelles) in fossil cyclostome eyes. Time of flight secondary ion mass spectrometry analyses reveal secondary ions with a relative intensity characteristic of melanin as revealed through principal components analyses. Our data support the hypotheses that extant hagfish eyes are degenerate, not rudimentary, that cyclostomes are monophyletic, and that the ancestral vertebrate had a functional visual system. We also demonstrate integument pigmentation in fossil lampreys, opening up the exciting possibility of investigating colour patterning in Palaeozoic vertebrates. The examples we report add to the record of melanosome preservation in Carboniferous fossils and attest to surprising durability of melanosomes and biomolecular melanin. PMID:27488650

  12. The beet Y locus encodes an anthocyanin MYB-like protein that activates the betalain red pigment pathway.

    PubMed

    Hatlestad, Gregory J; Akhavan, Neda A; Sunnadeniya, Rasika M; Elam, Lee; Cargile, Scott; Hembd, Austin; Gonzalez, Antonio; McGrath, J Mitchell; Lloyd, Alan M

    2015-01-01

    Nearly all flowering plants produce red/violet anthocyanin pigments. Caryophyllales is the only order containing families that replace anthocyanins with unrelated red and yellow betalain pigments. Close biological correlation of pigmentation patterns suggested that betalains might be regulated by a conserved anthocyanin-regulating transcription factor complex consisting of a MYB, a bHLH and a WD repeat-containing protein (the MBW complex). Here we show that a previously uncharacterized anthocyanin MYB-like protein, Beta vulgaris MYB1 (BvMYB1), regulates the betalain pathway in beets. Silencing BvMYB1 downregulates betalain biosynthetic genes and pigmentation, and overexpressing BvMYB1 upregulates them. However, unlike anthocyanin MYBs, BvMYB1 will not interact with bHLH members of heterologous anthocyanin MBW complexes because of identified nonconserved residues. BvMYB1 resides at the historic beet pigment-patterning locus, Y, required for red-fleshed beets. We show that Y and y express different levels of BvMYB1 transcripts. The co-option of a transcription factor regulating anthocyanin biosynthesis would be an important evolutionary event allowing betalains to largely functionally replace anthocyanins.

  13. Pathway redesign for deoxyviolacein biosynthesis in Citrobacter freundii and characterization of this pigment.

    PubMed

    Jiang, Pei-xia; Wang, Hai-sheng; Xiao, Su; Fang, Ming-yue; Zhang, Rui-ping; He, Shu-ying; Lou, Kai; Xing, Xin-Hui

    2012-06-01

    Violacein (Vio) is an important purple pigment with many potential bioactivities. Deoxyviolacein, a structural analog of Vio, is always synthesized in low concentrations with Vio in wild-type bacteria. Due to deoxyviolacein's low production and difficulties in isolation and purification, little has been learned regarding its function and potential applications. This study was the first effort in developing a stable and efficient biosynthetic system for producing pure deoxyviolacein. A recombinant plasmid with vioabce genes was constructed by splicing using an overlapping extension-polymerase chain reaction, based on the Vio-synthesizing gene cluster of vioabcde, originating from Duganella sp. B2, and was introduced into Citrobacter freundii. With the viod gene disrupted in the Vio synthetic pathway, Vio production was completely abolished and the recombinant C. freundii synthesized only deoxyviolacein. Interestingly, vioe gene expression was strongly stimulated in the viod-deleted recombinant strain, indicating that viod disruptions could potentially induce polar effects upon the downstream vioe gene within this small operon. Deoxyviolacein production by this strain reached 1.9 g/L in shaker flasks. The product exhibited significant acid/alkali and UV resistance as well as significant inhibition of hepatocellular carcinoma cell proliferation at low concentrations of 0.1-1 μM. These physical characteristics and antitumor activities of deoxyviolacein contribute to illuminating its potential applications.

  14. The Role of IRE-XBP1 Pathway in Regulation of Retinal Pigment Epithelium Tight Junctions

    PubMed Central

    Ma, Jacey H.; Wang, Joshua J.; Li, Junhua; Pfeffer, Bruce A.; Zhong, Yiming; Zhang, Sarah X.

    2016-01-01

    Purpose The retinal pigment epithelium (RPE) tight junctions play a pivotal role in maintaining the homeostatic environment of the neural retina. Herein, we investigated the role of X-box binding protein 1 (XBP1), an endoplasmic reticulum (ER) stress-responsive transcription factor, in regulation of RPE tight junctions. Methods Human RPE cell line (ARPE-19) and primary primate RPE cells were used for in vitro experiments and RPE-specific XBP1 knockout (KO) mice were used for in vivo study. Endoplasmic reticulum stress was induced by a sublethal dose of thapsigargin or tunicamycin. XBP1 activation was manipulated by IRE inhibitor 4μ8C, which suppresses XBP1 mRNA splicing. The integrity of tight junctions and the involvement of calcium-dependent RhoA/Rho kinase pathway were examined. Results Induction of ER stress by thapsigargin, but not tunicamycin, disrupted RPE tight junctions in ARPE-19 cells. Inhibition of XBP1 activation by 4μ8C resulted in a remarkable downregulation of tight junction proteins (ZO-1 and occludin) and defects in tight junction formation in the presence or absence of ER stress inducers. Overexpression of active XBP1 partially reversed 4μ8C-induced anomalies in tight junctions. Mechanistically, XBP1 inhibition resulted in increased intracellular Ca2+ concentration, upregulation of RhoA expression, redistribution of F-actin, and tight junction damage, which was attenuated by Rho kinase inhibitor Y27632. In vivo, deletion of XBP1 in the RPE resulted in defective RPE tight junctions accompanied by increased VEGF expression. Conclusions Taken together, these results suggest a protective role of XBP1 in maintaining RPE tight junctions possibly through regulation of calcium-dependent RhoA/Rho kinase signaling and actin cytoskeletal reorganization. PMID:27701635

  15. The Convergent Evolution of Blue Iris Pigmentation in Primates Took Distinct Molecular Paths

    PubMed Central

    Meyer, Wynn K; Zhang, Sidi; Hayakawa, Sachiko; Imai, Hiroo; Przeworski, Molly

    2013-01-01

    How many distinct molecular paths lead to the same phenotype? One approach to this question has been to examine the genetic basis of convergent traits, which likely evolved repeatedly under a shared selective pressure. We investigated the convergent phenotype of blue iris pigmentation, which has arisen independently in four primate lineages: humans, blue-eyed black lemurs, Japanese macaques, and spider monkeys. Characterizing the phenotype across these species, we found that the variation within the blue-eyed subsets of each species occupies strongly overlapping regions of CIE L*a*b* color space. Yet whereas Japanese macaques and humans display continuous variation, the phenotypes of blue-eyed black lemurs and their sister species (whose irises are brown) occupy more clustered subspaces. Variation in an enhancer of OCA2 is primarily responsible for the phenotypic difference between humans with blue and brown irises. In the orthologous region, we found no variant that distinguishes the two lemur species or associates with quantitative phenotypic variation in Japanese macaques. Given the high similarity between the blue iris phenotypes in these species and that in humans, this finding implies that evolution has used different molecular paths to reach the same end. Am J Phys Anthropol 151:398–407, 2013.© 2013 Wiley Periodicals, Inc. PMID:23640739

  16. Evolution of focal choroidal excavation underlying combined hamartoma of the retina and retinal pigment epithelium in a child.

    PubMed

    Sivalingam, Meera D; Say, Emil Anthony T; Shields, Carol L

    2015-08-01

    Combined hamartoma of the retina and retinal pigment epithelium (RPE) is a benign tumor seen mostly in children. Enhanced-depth imaging optical coherence tomography (OCT) of these tumors often shows an epiretinal membrane, tangential traction, disorganization of the retinal layers, and underlying uniform choroidal thinning. We describe the evolution over 9 years of focal choroidal excavation, a novel finding on OCT characterized as a "microstaphyloma," in a girl with combined hamartoma of the retina and RPE.

  17. A scenario for the evolution of selective egg coloration: the roles of enemy-free space, camouflage, thermoregulation and pigment limitation

    PubMed Central

    Torres-Campos, Inmaculada; Abram, Paul K.; Guerra-Grenier, Eric; Boivin, Guy; Brodeur, Jacques

    2016-01-01

    Behavioural plasticity can drive the evolution of new traits in animals. In oviparous species, plasticity in oviposition behaviour could promote the evolution of new egg traits by exposing them to different selective pressures in novel oviposition sites. Individual females of the predatory stink bug Podisus maculiventris are able to selectively colour their eggs depending on leaf side, laying lightly pigmented eggs on leaf undersides and more pigmented eggs, which are more resistant to ultraviolet (UV) radiation damage, on leaf tops. Here, we propose an evolutionary scenario for P. maculiventris egg pigmentation and its selective application. We experimentally tested the influence of several ecological factors that: (i) could have favoured a behavioural shift towards laying eggs on leaf tops and thus the evolution of a UV-protective egg pigment (i.e. exploitation of enemy-reduced space or a thermoregulatory benefit) and (ii) could have subsequently led to the evolution of selective pigment application (i.e. camouflage or costly pigment production). We found evidence that a higher predation pressure on leaf undersides could have caused a shift in oviposition effort towards leaf tops. We also found the first evidence of an insect egg pigment providing a thermoregulatory advantage. Our study contributes to an understanding of how plasticity in oviposition behaviour could shape the responses of organisms to ecological factors affecting their reproductive success, spurring the evolution of new morphological traits. PMID:27152215

  18. Experimental evolution reveals hidden diversity in evolutionary pathways.

    PubMed

    Lind, Peter A; Farr, Andrew D; Rainey, Paul B

    2015-03-25

    Replicate populations of natural and experimental organisms often show evidence of parallel genetic evolution, but the causes are unclear. The wrinkly spreader morph of Pseudomonas fluorescens arises repeatedly during experimental evolution. The mutational causes reside exclusively within three pathways. By eliminating these, 13 new mutational pathways were discovered with the newly arising WS types having fitnesses similar to those arising from the commonly passaged routes. Our findings show that parallel genetic evolution is strongly biased by constraints and we reveal the genetic bases. From such knowledge, and in instances where new phenotypes arise via gene activation, we suggest a set of principles: evolution proceeds firstly via pathways subject to negative regulation, then via promoter mutations and gene fusions, and finally via activation by intragenic gain-of-function mutations. These principles inform evolutionary forecasting and have relevance to interpreting the diverse array of mutations associated with clinically identical instances of disease in humans.

  19. Phylogenetic evidence for the modular evolution of metazoan signalling pathways.

    PubMed

    Babonis, Leslie S; Martindale, Mark Q

    2017-02-05

    Communication among cells was paramount to the evolutionary increase in cell type diversity and, ultimately, the origin of large body size. Across the diversity of Metazoa, there are only few conserved cell signalling pathways known to orchestrate the complex cell and tissue interactions regulating development; thus, modification to these few pathways has been responsible for generating diversity during the evolution of animals. Here, we summarize evidence for the origin and putative function of the intracellular, membrane-bound and secreted components of seven metazoan cell signalling pathways with a special focus on early branching metazoans (ctenophores, poriferans, placozoans and cnidarians) and basal unikonts (amoebozoans, fungi, filastereans and choanoflagellates). We highlight the modular incorporation of intra- and extracellular components in each signalling pathway and suggest that increases in the complexity of the extracellular matrix may have further promoted the modulation of cell signalling during metazoan evolution. Most importantly, this updated view of metazoan signalling pathways highlights the need for explicit study of canonical signalling pathway components in taxa that do not operate a complete signalling pathway. Studies like these are critical for developing a deeper understanding of the evolution of cell signalling.This article is part of the themed issue 'Evo-devo in the genomics era, and the origins of morphological diversity'.

  20. The Evolution of Fungal Metabolic Pathways

    PubMed Central

    Rokas, Antonis

    2014-01-01

    Fungi contain a remarkable range of metabolic pathways, sometimes encoded by gene clusters, enabling them to digest most organic matter and synthesize an array of potent small molecules. Although metabolism is fundamental to the fungal lifestyle, we still know little about how major evolutionary processes, such as gene duplication (GD) and horizontal gene transfer (HGT), have interacted with clustered and non-clustered fungal metabolic pathways to give rise to this metabolic versatility. We examined the synteny and evolutionary history of 247,202 fungal genes encoding enzymes that catalyze 875 distinct metabolic reactions from 130 pathways in 208 diverse genomes. We found that gene clustering varied greatly with respect to metabolic category and lineage; for example, clustered genes in Saccharomycotina yeasts were overrepresented in nucleotide metabolism, whereas clustered genes in Pezizomycotina were more common in lipid and amino acid metabolism. The effects of both GD and HGT were more pronounced in clustered genes than in their non-clustered counterparts and were differentially distributed across fungal lineages; specifically, GD, which was an order of magnitude more abundant than HGT, was most frequently observed in Agaricomycetes, whereas HGT was much more prevalent in Pezizomycotina. The effect of HGT in some Pezizomycotina was particularly strong; for example, we identified 111 HGT events associated with the 15 Aspergillus genomes, which sharply contrasts with the 60 HGT events detected for the 48 genomes from the entire Saccharomycotina subphylum. Finally, the impact of GD within a metabolic category was typically consistent across all fungal lineages, whereas the impact of HGT was variable. These results indicate that GD is the dominant process underlying fungal metabolic diversity, whereas HGT is episodic and acts in a category- or lineage-specific manner. Both processes have a greater impact on clustered genes, suggesting that metabolic gene clusters

  1. The evolution of fungal metabolic pathways.

    PubMed

    Wisecaver, Jennifer H; Slot, Jason C; Rokas, Antonis

    2014-12-01

    Fungi contain a remarkable range of metabolic pathways, sometimes encoded by gene clusters, enabling them to digest most organic matter and synthesize an array of potent small molecules. Although metabolism is fundamental to the fungal lifestyle, we still know little about how major evolutionary processes, such as gene duplication (GD) and horizontal gene transfer (HGT), have interacted with clustered and non-clustered fungal metabolic pathways to give rise to this metabolic versatility. We examined the synteny and evolutionary history of 247,202 fungal genes encoding enzymes that catalyze 875 distinct metabolic reactions from 130 pathways in 208 diverse genomes. We found that gene clustering varied greatly with respect to metabolic category and lineage; for example, clustered genes in Saccharomycotina yeasts were overrepresented in nucleotide metabolism, whereas clustered genes in Pezizomycotina were more common in lipid and amino acid metabolism. The effects of both GD and HGT were more pronounced in clustered genes than in their non-clustered counterparts and were differentially distributed across fungal lineages; specifically, GD, which was an order of magnitude more abundant than HGT, was most frequently observed in Agaricomycetes, whereas HGT was much more prevalent in Pezizomycotina. The effect of HGT in some Pezizomycotina was particularly strong; for example, we identified 111 HGT events associated with the 15 Aspergillus genomes, which sharply contrasts with the 60 HGT events detected for the 48 genomes from the entire Saccharomycotina subphylum. Finally, the impact of GD within a metabolic category was typically consistent across all fungal lineages, whereas the impact of HGT was variable. These results indicate that GD is the dominant process underlying fungal metabolic diversity, whereas HGT is episodic and acts in a category- or lineage-specific manner. Both processes have a greater impact on clustered genes, suggesting that metabolic gene clusters

  2. The Silk-protein Sericin Induces Rapid Melanization of Cultured Primary Human Retinal Pigment Epithelial Cells by Activating the NF-κB Pathway.

    PubMed

    Eidet, J R; Reppe, S; Pasovic, L; Olstad, O K; Lyberg, T; Khan, A Z; Fostad, I G; Chen, D F; Utheim, T P

    2016-03-04

    Restoration of the retinal pigment epithelial (RPE) cells to prevent further loss of vision in patients with age-related macular degeneration represents a promising novel treatment modality. Development of RPE transplants, however, requires up to 3 months of cell differentiation. We explored whether the silk protein sericin can induce maturation of primary human retinal pigment epithelial (hRPE) cells. Microarray analysis demonstrated that sericin up-regulated RPE-associated transcripts (RPE65 and CRALBP). Upstream analysis identified the NF-κB pathway as one of the top sericin-induced regulators. ELISA confirmed that sericin stimulates the main NF-κB pathway. Increased levels of RPE-associated proteins (RPE65 and the pigment melanin) in the sericin-supplemented cultures were confirmed by western blot, spectrophotometry and transmission electron microscopy. Sericin also increased cell density and reduced cell death following serum starvation in culture. Inclusion of NF-κB agonists and antagonists in the culture medium showed that activation of the NF-κB pathway appears to be necessary, but not sufficient, for sericin-induced RPE pigmentation. We conclude that sericin promotes pigmentation of cultured primary hRPE cells by activating the main NF-κB pathway. Sericin's potential role in culture protocols for rapid differentiation of hRPE cells derived from embryonic or induced pluripotent stem cells should be investigated.

  3. The Silk-protein Sericin Induces Rapid Melanization of Cultured Primary Human Retinal Pigment Epithelial Cells by Activating the NF-κB Pathway

    PubMed Central

    Eidet, J. R.; Reppe, S.; Pasovic, L.; Olstad, O. K.; Lyberg, T.; Khan, A. Z.; Fostad, I. G.; Chen, D. F.; Utheim, T. P.

    2016-01-01

    Restoration of the retinal pigment epithelial (RPE) cells to prevent further loss of vision in patients with age-related macular degeneration represents a promising novel treatment modality. Development of RPE transplants, however, requires up to 3 months of cell differentiation. We explored whether the silk protein sericin can induce maturation of primary human retinal pigment epithelial (hRPE) cells. Microarray analysis demonstrated that sericin up-regulated RPE-associated transcripts (RPE65 and CRALBP). Upstream analysis identified the NF-κB pathway as one of the top sericin-induced regulators. ELISA confirmed that sericin stimulates the main NF-κB pathway. Increased levels of RPE-associated proteins (RPE65 and the pigment melanin) in the sericin-supplemented cultures were confirmed by western blot, spectrophotometry and transmission electron microscopy. Sericin also increased cell density and reduced cell death following serum starvation in culture. Inclusion of NF-κB agonists and antagonists in the culture medium showed that activation of the NF-κB pathway appears to be necessary, but not sufficient, for sericin-induced RPE pigmentation. We conclude that sericin promotes pigmentation of cultured primary hRPE cells by activating the main NF-κB pathway. Sericin’s potential role in culture protocols for rapid differentiation of hRPE cells derived from embryonic or induced pluripotent stem cells should be investigated. PMID:26940175

  4. Oxygen and the evolution of metabolic pathways

    NASA Technical Reports Server (NTRS)

    Jahnke, L. L.

    1986-01-01

    While a considerable amount of evidence has been accumulated about the history of oxygen on this planet, little is known about the relative amounts to which primitive cells might have been exposed. One clue may be found in the metabolic pathways of extant microorganisms. While eucaryotes are principally aerobic organisms, a number are capable of anaerobic growth by fermentation. One such eucaryotic microorganism, Saccharomyces cerevisiae, will grow in the complete absence of oxygen when supplemented with unsaturated fatty acid and sterol. Oxygen-requiring enzymes are involved in the synthesis of both of these compounds. Studies have demonstrated that the oxidative desaturation of palmitic acid and the conversion of squalene to sterols occur in the range of 10-(3) to 10(-2) PAL. Thus, if the oxygen requirements of these enzymatic processes are an indication, eucaryotes might be more primitive than anticipated from the microfossil record. Results of studies on the oxygen requirements for sterol and unsaturated fatty acid synthesis in a more primitive procaryotic system are also discussed.

  5. Lutein Inhibits the Migration of Retinal Pigment Epithelial Cells via Cytosolic and Mitochondrial Akt Pathways (Lutein Inhibits RPE Cells Migration)

    PubMed Central

    Su, Ching-Chieh; Chan, Chi-Ming; Chen, Han-Min; Wu, Chia-Chun; Hsiao, Chien-Yu; Lee, Pei-Lan; Lin, Victor Chia-Hsiang; Hung, Chi-Feng

    2014-01-01

    During the course of proliferative vitreoretinopathy (PVR), the retinal pigment epithelium (RPE) cells will de-differentiate, proliferate, and migrate onto the surfaces of the sensory retina. Several studies have shown that platelet-derived growth factor (PDGF) can induce migration of RPE cells via an Akt-related pathway. In this study, the effect of lutein on PDGF-BB-induced RPE cells migration was examined using transwell migration assays and Western blot analyses. We found that both phosphorylation of Akt and mitochondrial translocation of Akt in RPE cells induced by PDGF-BB stimulation were suppressed by lutein. Furthermore, the increased migration observed in RPE cells with overexpressed mitochondrial Akt could also be suppressed by lutein. Our results demonstrate that lutein can inhibit PDGF-BB induced RPE cells migration through the inhibition of both cytoplasmic and mitochondrial Akt activation. PMID:25110866

  6. Experimental evolution reveals hidden diversity in evolutionary pathways

    PubMed Central

    Lind, Peter A; Farr, Andrew D; Rainey, Paul B

    2015-01-01

    Replicate populations of natural and experimental organisms often show evidence of parallel genetic evolution, but the causes are unclear. The wrinkly spreader morph of Pseudomonas fluorescens arises repeatedly during experimental evolution. The mutational causes reside exclusively within three pathways. By eliminating these, 13 new mutational pathways were discovered with the newly arising WS types having fitnesses similar to those arising from the commonly passaged routes. Our findings show that parallel genetic evolution is strongly biased by constraints and we reveal the genetic bases. From such knowledge, and in instances where new phenotypes arise via gene activation, we suggest a set of principles: evolution proceeds firstly via pathways subject to negative regulation, then via promoter mutations and gene fusions, and finally via activation by intragenic gain-of-function mutations. These principles inform evolutionary forecasting and have relevance to interpreting the diverse array of mutations associated with clinically identical instances of disease in humans. DOI: http://dx.doi.org/10.7554/eLife.07074.001 PMID:25806684

  7. The beet Y locus encodes an anthocyanin-MYB-like protein that activates the betalain red pigment pathway

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Almost all flowering plants produce red/violet, phenylalanine-based, anthocyanin pigments. A single order, the Caryophyllales, contains families that replace anthocyanins with tyrosine-based red and yellow betalain pigments. Close biological correlation of pigmentation patterns suggested that betala...

  8. Sequence and evolution of the blue cone pigment gene in old and new world primates

    SciTech Connect

    Hunt, D.M.; Cowing, J.A.; Patel, R.

    1995-06-10

    The sequences of the blue cone photopigments in the talapoin monkey (Miopithecus talapoin), an Old World primate, and in the marmoset (Callithrix jacchus), a New World monkey, are presented. Both genes are composed of 5 exons separated by 4 introns. In this respect, they are identical to the human blue gene, and intron sizes are also similar. Based on the level of amino acid identity, both monkey pigments are members of the S branch of pigments. Alignment of these sequences with the human gene requires the insertion/deletion of two separate codons in exon 1. The silent site divergence between these primate blue genes indicates a separation of the Old and New World primate lineages around 43 million years ago. 41 refs., 1 fig., 3 tabs.

  9. Was skin cancer a selective force for black pigmentation in early hominin evolution?

    PubMed

    Greaves, Mel

    2014-04-22

    Melanin provides a crucial filter for solar UV radiation and its genetically determined variation influences both skin pigmentation and risk of cancer. Genetic evidence suggests that the acquisition of a highly stable melanocortin 1 receptor allele promoting black pigmentation arose around the time of savannah colonization by hominins at some 1-2 Ma. The adaptive significance of dark skin is generally believed to be protection from UV damage but the pathologies that might have had a deleterious impact on survival and/or reproductive fitness, though much debated, are uncertain. Here, I suggest that data on age-associated cancer incidence and lethality in albinos living at low latitudes in both Africa and Central America support the contention that skin cancer could have provided a potent selective force for the emergence of black skin in early hominins.

  10. Was skin cancer a selective force for black pigmentation in early hominin evolution?

    PubMed Central

    Greaves, Mel

    2014-01-01

    Melanin provides a crucial filter for solar UV radiation and its genetically determined variation influences both skin pigmentation and risk of cancer. Genetic evidence suggests that the acquisition of a highly stable melanocortin 1 receptor allele promoting black pigmentation arose around the time of savannah colonization by hominins at some 1–2 Ma. The adaptive significance of dark skin is generally believed to be protection from UV damage but the pathologies that might have had a deleterious impact on survival and/or reproductive fitness, though much debated, are uncertain. Here, I suggest that data on age-associated cancer incidence and lethality in albinos living at low latitudes in both Africa and Central America support the contention that skin cancer could have provided a potent selective force for the emergence of black skin in early hominins. PMID:24573849

  11. Horizontal gene transfer and the evolution of methanogenic pathways.

    PubMed

    Fournier, Greg

    2009-01-01

    Horizontal gene transfer (HGT) is a driving force in the evolution of metabolic pathways, allowing novel enzymatic functions that provide a selective advantage to be rapidly incorporated into an organism's physiology. Here, the role of two HGT events in the evolution of methanogenesis is described. First, the acetoclastic sub-pathway of methanogenesis is shown to have evolved via a transfer of the ackA and pta genes from a cellulolytic clostridia to a family of methanogenic archaea. Second, the system for encoding the amino acid pyrrolysine, used for the synthesis of enzymes for methanogenesis from methylamines, is shown to likely have evolved via transfer from an ancient, unknown, deeply branching organismal lineage.

  12. Association of the OCA2 Polymorphism His615Arg with Melanin Content in East Asian Populations: Further Evidence of Convergent Evolution of Skin Pigmentation

    PubMed Central

    Edwards, Melissa; Bigham, Abigail; Tan, Jinze; Li, Shilin; Gozdzik, Agnes; Ross, Kendra; Jin, Li; Parra, Esteban J.

    2010-01-01

    The last decade has witnessed important advances in our understanding of the genetics of pigmentation in European populations, but very little is known about the genes involved in skin pigmentation variation in East Asian populations. Here, we present the results of a study evaluating the association of 10 Single Nucleotide Polymorphisms (SNPs) located within 5 pigmentation candidate genes (OCA2, DCT, ADAM17, ADAMTS20, and TYRP1) with skin pigmentation measured quantitatively in a sample of individuals of East Asian ancestry living in Canada. We show that the non-synonymous polymorphism rs1800414 (His615Arg) located within the OCA2 gene is significantly associated with skin pigmentation in this sample. We replicated this result in an independent sample of Chinese individuals of Han ancestry. This polymorphism is characterized by a derived allele that is present at a high frequency in East Asian populations, but is absent in other population groups. In both samples, individuals with the derived G allele, which codes for the amino acid arginine, show lower melanin levels than those with the ancestral A allele, which codes for the amino acid histidine. An analysis of this non-synonymous polymorphism using several programs to predict potential functional effects provides additional support for the role of this SNP in skin pigmentation variation in East Asian populations. Our results are consistent with previous research indicating that evolution to lightly-pigmented skin occurred, at least in part, independently in Europe and East Asia. PMID:20221248

  13. Isomerization and Oxidation of Vitamin A in Cone-Dominant Retinas: A Novel Pathway for Visual-Pigment Regeneration in Daylight

    PubMed Central

    Mata, Nathan L.; Radu, Roxana A.; Clemmons, Richard S.; Travis, Gabriel H.

    2010-01-01

    Summary The first step toward light perception is 11-cis to all-trans photoisomerization of the retinaldehyde chromophore in a rod or cone opsin-pigment molecule. Light sensitivity of the opsin pigment is restored through a multistep pathway called the visual cycle, which effects all-trans to 11-cis re-isomerization of the retinoid chromophore. The maximum throughput of the known visual cycle, however, is too slow to explain sustained photosensitivity in bright light. Here, we demonstrate three novel enzymatic activities in cone-dominant ground-squirrel and chicken retinas: an all-trans-retinol isomerase, an 11-cis-retinyl-ester synthase, and an 11-cis-retinol dehydrogenase. Together these activities comprise a novel pathway that regenerates opsin photopigments at a rate 20-fold faster than the known visual cycle. We suggest that this pathway is responsible for sustained daylight vision in vertebrates. PMID:12367507

  14. In silico study for diversing the molecular pathway of pigment formation: an alternative to manual coloring in cotton fibers

    PubMed Central

    Ahad, Ammara; Ahmad, Aftab; Din, Salah ud; Rao, Abdul Q.; Shahid, Ahmad A.; Husnain, Tayyab

    2015-01-01

    Diversity of colors in flowers and fruits is largely due to anthocyanin pigments. The flavonoid/anthocyanin pathway has been most extensively studied. Dihydroflavonol 4-reductase (DFR) is a vital enzyme of the flavonoid pathway which displays major impact on the formation of anthocyanins, flavan 3-ols and flavonols. The substrate specificity of the DFR was found to play a crucial role in determination of type of anthocyanidins. Altering the flavonoid/anthocyanin pathway through genetic engineering to develop color of our own choice is an exciting subject of future research. In the present study, comparison among four DFR genes (Gossypium hirsutum, Iris × hollandica, Ang. DFRI and DFRII), sequence alignment for homology as well as protein modeling and docking is demonstrated. Estimation of catalytic sites, prediction of substrate preference and protein docking were the key features of this article. For specific substrate uptake, a proline rich region and positions 12 plus 26 along with other positions emphasizing the 26-amino acid residue region (132–157) was tested. Results showed that proline rich region position 12, 26, and 132–157 plays an important role in selective attachment of DFRs with respective substrates. Further, “Expasy ProtParam tool” results showed that Iris × hollandica DFR amino acids (Asn 9: Asp 23) are favorable for reducing DHQ and DHM thus accumulating delphinidin, while Gossypium hirsutum DFR has (Asn 13: Asp 21) hypothesized to consume DHK. Protein docking data showed that amino acid residues in above mentioned positions were just involved in attachment of DFR with substrate and had no role in specific substrate uptake. Advanced bioinformatics analysis has revealed that all above mentioned positions have role in substrate attachment. For substrate specificity, other residues region is involved. It will help in color manipulations in different plant species. PMID:26442064

  15. Long-distance communication by specialized cellular projections during pigment pattern development and evolution

    PubMed Central

    Eom, Dae Seok; Bain, Emily J; Patterson, Larissa B; Grout, Megan E; Parichy, David M

    2015-01-01

    Changes in gene activity are essential for evolutionary diversification. Yet, elucidating the cellular behaviors that underlie modifications to adult form remains a profound challenge. We use neural crest-derived adult pigmentation of zebrafish and pearl danio to uncover cellular bases for alternative pattern states. We show that stripes in zebrafish require a novel class of thin, fast cellular projection to promote Delta-Notch signaling over long distances from cells of the xanthophore lineage to melanophores. Projections depended on microfilaments and microtubules, exhibited meandering trajectories, and stabilized on target cells to which they delivered membraneous vesicles. By contrast, the uniformly patterned pearl danio lacked such projections, concomitant with Colony stimulating factor 1-dependent changes in xanthophore differentiation that likely curtail signaling available to melanophores. Our study reveals a novel mechanism of cellular communication, roles for differentiation state heterogeneity in pigment cell interactions, and an unanticipated morphogenetic behavior contributing to a striking difference in adult form. DOI: http://dx.doi.org/10.7554/eLife.12401.001 PMID:26701906

  16. In vivo continuous evolution of genes and pathways in yeast

    PubMed Central

    Crook, Nathan; Abatemarco, Joseph; Sun, Jie; Wagner, James M.; Schmitz, Alexander; Alper, Hal S.

    2016-01-01

    Directed evolution remains a powerful, highly generalizable approach for improving the performance of biological systems. However, implementations in eukaryotes rely either on in vitro diversity generation or limited mutational capacities. Here we synthetically optimize the retrotransposon Ty1 to enable in vivo generation of mutant libraries up to 1.6 × 107 l−1 per round, which is the highest of any in vivo mutational generation approach in yeast. We demonstrate this approach by using in vivo-generated libraries to evolve single enzymes, global transcriptional regulators and multi-gene pathways. When coupled to growth selection, this approach enables in vivo continuous evolution (ICE) of genes and pathways. Through a head-to-head comparison, we find that ICE libraries yield higher-performing variants faster than error-prone PCR-derived libraries. Finally, we demonstrate transferability of ICE to divergent yeasts, including Kluyveromyces lactis and alternative S. cerevisiae strains. Collectively, this work establishes a generic platform for rapid eukaryotic-directed evolution across an array of target cargo. PMID:27748457

  17. DKK1 inhibits proliferation and migration in human retinal pigment epithelial cells via the Wnt/β-catenin signaling pathway.

    PubMed

    Zhou, Jinzi; Jiang, Jian; Wang, Shuhong; Xia, Xiaobo

    2016-08-01

    Retinal pigment epithelial (RPE) cells play important roles in diabetic retinopathy (DR). Dickkopf 1 (DKK1) has been reported to be important in the regulation of cell proliferation and migration. However, there are few previous studies regarding DKK1 in RPE cells. Therefore, in the present study, we investigated the effect of DKK1 on the proliferation and migration of human RPE cells, and the signaling mechanisms underlying these effects. The results showed that the overexpression of DKK1 significantly inhibited the proliferation and migration of ARPE-19 cells. In addition, overexpression of DKK1 markedly inhibited the expression of β-catenin and cyclin D1 in ARPE-19 cells. Collectively, the present findings suggest that the overexpression of DKK1 inhibited the proliferation and migration of RPE cells by suppressing the Wnt/β-catenin signaling pathway. Therefore, DKK1 are able to augment the growth of human RPE, and further studies are warranted to investigate the effects of DKK1 effects on DR.

  18. MC1R, the cAMP pathway, and the response to solar UV: extending the horizon beyond pigmentation.

    PubMed

    García-Borrón, Jose C; Abdel-Malek, Zalfa; Jiménez-Cervantes, Celia

    2014-09-01

    The melanocortin 1 receptor (MC1R) is a G protein-coupled receptor crucial for the regulation of melanocyte proliferation and function. Upon binding melanocortins, MC1R activates several signaling cascades, notably the cAMP pathway leading to synthesis of photoprotective eumelanin. Polymorphisms in the MC1R gene are a major source of normal variation of human hair color and skin pigmentation, response to ultraviolet radiation (UVR), and skin cancer susceptibility. The identification of a surprisingly high number of MC1R natural variants strongly associated with pigmentary phenotypes and increased skin cancer risk has prompted research on the functional properties of the wild-type receptor and frequent mutant alleles. We summarize current knowledge on MC1R structural and functional properties, as well as on its intracellular trafficking and signaling. We also review the current knowledge about the function of MC1R as a skin cancer, particularly melanoma, susceptibility gene and how it modulates the response of melanocytes to UVR.

  19. MC1R, the cAMP pathway and the response to solar UV: Extending the horizon beyond pigmentation

    PubMed Central

    García-Borrón, Jose C; Abdel-Malek, Zalfa; Jiménez-Cervantes, Celia

    2014-01-01

    Summary The melanocortin 1 receptor (MC1R) is a G protein-coupled receptor crucial for the regulation of melanocyte proliferation and function. Upon binding melanocortins, MC1R activates several signaling cascades, notably the cAMP pathway leading to synthesis of photoprotective eumelanin. Polymorphisms in the MC1R gene are a major source of normal variation of human hair color and skin pigmentation, response to ultraviolet radiation (UVR) and skin cancer susceptibility. The identification of a surprisingly high number of MC1R natural variants strongly associated with pigmentary phenotypes and increased skin cancer risk has prompted research on the functional properties of the wild-type receptor and frequent mutant alleles. We summarize current knowledge on MC1R structural and functional properties, as well as on its intracellular trafficking and signaling. We also review the current knowledge about the function of MC1R as a skin cancer, particularly melanoma, susceptibility gene and how it modulates the response of melanocytes to UVR. PMID:24807163

  20. Insight into the evolution of the iron oxidation pathways.

    PubMed

    Ilbert, Marianne; Bonnefoy, Violaine

    2013-02-01

    Iron is a ubiquitous element in the universe. Ferrous iron (Fe(II)) was abundant in the primordial ocean until the oxygenation of the Earth's atmosphere led to its widespread oxidation and precipitation. This change of iron bioavailability likely put selective pressure on the evolution of life. This element is essential to most extant life forms and is an important cofactor in many redox-active proteins involved in a number of vital pathways. In addition, iron plays a central role in many environments as an energy source for some microorganisms. This review is focused on Fe(II) oxidation. The fact that the ability to oxidize Fe(II) is widely distributed in Bacteria and Archaea and in a number of quite different biotopes suggests that the dissimilatory Fe(II) oxidation is an ancient energy metabolism. Based on what is known today about Fe(II) oxidation pathways, we propose that they arose independently more than once in evolution and evolved convergently. The iron paleochemistry, the phylogeny, the physiology of the iron oxidizers, and the nature of the cofactors of the redox proteins involved in these pathways suggest a possible scenario for the timescale in which each type of Fe(II) oxidation pathways evolved. The nitrate dependent anoxic iron oxidizers are likely the most ancient iron oxidizers. We suggest that the phototrophic anoxic iron oxidizers arose in surface waters after the Archaea/Bacteria-split but before the Great Oxidation Event. The neutrophilic oxic iron oxidizers possibly appeared in microaerobic marine environments prior to the Great Oxidation Event while the acidophilic ones emerged likely after the advent of atmospheric O(2). This article is part of a Special Issue entitled: The evolutionary aspects of bioenergetic systems.

  1. Vitreous-induced cytoskeletal rearrangements via the Rac1 GTPase-dependent signaling pathway in human retinal pigment epithelial cells

    SciTech Connect

    Huang, Xionggao; Wei, Yantao; Ma, Haizhi; Zhang, Shaochong

    2012-03-09

    Highlights: Black-Right-Pointing-Pointer Vitreous induces morphological changes and cytoskeletal rearrangements in RPE cells. Black-Right-Pointing-Pointer Rac1 is activated in vitreous-transformed RPE cells. Black-Right-Pointing-Pointer Rac inhibition prevents morphological changes in vitreous-transformed RPE cells. Black-Right-Pointing-Pointer Rac inhibition suppresses cytoskeletal rearrangements in vitreous-transformed RPE cells. Black-Right-Pointing-Pointer The vitreous-induced effects are mediated by a Rac1 GTPase/LIMK1/cofilin pathway. -- Abstract: Proliferative vitreoretinopathy (PVR) is mainly caused by retinal pigment epithelial (RPE) cell migration, invasion, proliferation and transformation into fibroblast-like cells that produce the extracellular matrix (ECM). The vitreous humor is known to play an important role in PVR. An epithelial-to-mesenchymal transdifferentiation (EMT) of human RPE cells induced by 25% vitreous treatment has been linked to stimulation of the mesenchymal phenotype, migration and invasion. Here, we characterized the effects of the vitreous on the cell morphology and cytoskeleton in human RPE cells. The signaling pathway that mediates these effects was investigated. Serum-starved RPE cells were incubated with 25% vitreous, and the morphological changes were examined by phase-contrast microscopy. Filamentous actin (F-actin) was examined by immunofluorescence and confocal microscopy. Protein phosphorylation of AKT, ERK1/2, Smad2/3, LIM kinase (LIMK) 1 and cofilin was analyzed by Western blot analysis. Vitreous treatment induced cytoskeletal rearrangements, activated Rac1 and enhanced the phosphorylation of AKT, ERK1/2 and Smad2/3. When the cells were treated with a Rac activation-specific inhibitor, the cytoskeletal rearrangements were prevented, and the phosphorylation of Smad2/3 was blocked. Vitreous treatment also enhanced the phosphorylation of LIMK1 and cofilin and the Rac inhibitor blocked this effect. We propose that vitreous

  2. Spectral shifts of mammalian ultraviolet-sensitive pigments (short wavelength-sensitive opsin 1) are associated with eye length and photic niche evolution.

    PubMed

    Emerling, Christopher A; Huynh, Hieu T; Nguyen, Minh A; Meredith, Robert W; Springer, Mark S

    2015-11-22

    Retinal opsin photopigments initiate mammalian vision when stimulated by light. Most mammals possess a short wavelength-sensitive opsin 1 (SWS1) pigment that is primarily sensitive to either ultraviolet or violet light, leading to variation in colour perception across species. Despite knowledge of both ultraviolet- and violet-sensitive SWS1 classes in mammals for 25 years, the adaptive significance of this variation has not been subjected to hypothesis testing, resulting in minimal understanding of the basis for mammalian SWS1 spectral tuning evolution. Here, we gathered data on SWS1 for 403 mammal species, including novel SWS1 sequences for 97 species. Ancestral sequence reconstructions suggest that the most recent common ancestor of Theria possessed an ultraviolet SWS1 pigment, and that violet-sensitive pigments evolved at least 12 times in mammalian history. We also observed that ultraviolet pigments, previously considered to be a rarity, are common in mammals. We then used phylogenetic comparative methods to test the hypotheses that the evolution of violet-sensitive SWS1 is associated with increased light exposure, extended longevity and longer eye length. We discovered that diurnal mammals and species with longer eyes are more likely to have violet-sensitive pigments and less likely to possess UV-sensitive pigments. We hypothesize that (i) as mammals evolved larger body sizes, they evolved longer eyes, which limited transmittance of ultraviolet light to the retina due to an increase in Rayleigh scattering, and (ii) as mammals began to invade diurnal temporal niches, they evolved lenses with low UV transmittance to reduce chromatic aberration and/or photo-oxidative damage.

  3. Spectral shifts of mammalian ultraviolet-sensitive pigments (short wavelength-sensitive opsin 1) are associated with eye length and photic niche evolution

    PubMed Central

    Emerling, Christopher A.; Huynh, Hieu T.; Nguyen, Minh A.; Meredith, Robert W.; Springer, Mark S.

    2015-01-01

    Retinal opsin photopigments initiate mammalian vision when stimulated by light. Most mammals possess a short wavelength-sensitive opsin 1 (SWS1) pigment that is primarily sensitive to either ultraviolet or violet light, leading to variation in colour perception across species. Despite knowledge of both ultraviolet- and violet-sensitive SWS1 classes in mammals for 25 years, the adaptive significance of this variation has not been subjected to hypothesis testing, resulting in minimal understanding of the basis for mammalian SWS1 spectral tuning evolution. Here, we gathered data on SWS1 for 403 mammal species, including novel SWS1 sequences for 97 species. Ancestral sequence reconstructions suggest that the most recent common ancestor of Theria possessed an ultraviolet SWS1 pigment, and that violet-sensitive pigments evolved at least 12 times in mammalian history. We also observed that ultraviolet pigments, previously considered to be a rarity, are common in mammals. We then used phylogenetic comparative methods to test the hypotheses that the evolution of violet-sensitive SWS1 is associated with increased light exposure, extended longevity and longer eye length. We discovered that diurnal mammals and species with longer eyes are more likely to have violet-sensitive pigments and less likely to possess UV-sensitive pigments. We hypothesize that (i) as mammals evolved larger body sizes, they evolved longer eyes, which limited transmittance of ultraviolet light to the retina due to an increase in Rayleigh scattering, and (ii) as mammals began to invade diurnal temporal niches, they evolved lenses with low UV transmittance to reduce chromatic aberration and/or photo-oxidative damage. PMID:26582021

  4. αvβ5 Integrin/FAK/PGC-1α Pathway Confers Protective Effects on Retinal Pigment Epithelium

    PubMed Central

    Roggia, Murilo F.; Ueta, Takashi

    2015-01-01

    Purpose To elucidate the mechanism of the induction of peroxisome proliferator-activated receptor γ coactivator-1α (PGC-1α) by photoreceptor outer segments (POS) and its effects on retinal pigment epithelium (RPE). Methods PGC-1α upregulation by POS was confirmed in ARPE-19 cells and in RPE ex vivo. To elucidate the mechanism, siRNAs against β5 integrin, CD36, Mer tyrosine kinase (MerTK), and Atg5, blocking antibodies against CD36 and MerTK, and a specific inhibitor for focal adhesion kinase (FAK) were used. We examined the effect of POS-induced PGC-1α upregulation on the levels of reactive oxygen species (ROS), mitochondrial biogenesis, senescence-associated β-galactosidase (SA-β-gal) after H2O2 treatment, and lysosomal activity. Lysosomal activity was evaluated through transcriptional factor EB and its target genes, and the activity of cathepsin D. Lipid metabolism after POS treatment was assessed using Oil Red O and BODIPY C11. RPE phenotypes of PGC-1α-deficient mice were examined. Results POS-induced PGC-1α upregulation was suppressed by siRNA against β5 integrin and a FAK inhibitor. siRNAs and blocking antibodies against CD36 and MerTK enhanced the effect of POS on PGC-1α. The upregulation of PGC-1α increased the levels of mRNA for antioxidant enzymes and stimulated mitochondrial biogenesis, decreased ROS levels, and reduced SA-β-gal staining in H2O2-treated ARPE-19 cells. PGC-1α was critical for lysosomal activity and lipid metabolism after POS treatment. PGC-1α-deficient mice demonstrated an accumulation of type 2 lysosomes in RPE, thickening of Bruch’s membrane, and poor choriocapillaris vasculature. Conclusions The binding, but not the internalization of POS confers protective effects on RPE cells through the αvβ5 integrin/FAK/PGC-1α pathway. PMID:26244551

  5. Ecology and sexual selection: evolution of wing pigmentation in calopterygid damselflies in relation to latitude, sexual dimorphism, and speciation.

    PubMed

    Svensson, Erik I; Waller, John T

    2013-11-01

    Our knowledge about how the environment influences sexual selection regimes and how ecology and sexual selection interact is still limited. We performed an integrative study of wing pigmentation in calopterygid damselflies, combining phylogenetic comparative analyses, field observations and experiments. We investigated the evolutionary consequences of wing pigmentation for sexual dimorphism, speciation, and extinction and addressed the possible thermoregulatory benefits of pigmentation. First, we reconstructed ancestral states of male and female phenotypes and traced the evolutionary change of wing pigmentation. Clear wings are the ancestral state and that pigmentation dimorphism is derived, suggesting that sexual selection results in sexual dimorphism. We further demonstrate that pigmentation elevates speciation and extinction rates. We also document a significant biogeographic association with pigmented species primarily occupying northern temperate regions with cooler climates. Field observations and experiments on two temperate sympatric species suggest a link between pigmentation, thermoregulation, and sexual selection, although body temperature is also affected by other phenotypic traits such as body mass, microhabitat selection, and thermoregulatory behaviors. Taken together, our results suggest an important role for wing pigmentation in sexual selection in males and in speciation. Wing pigmentation might not increase ecological adaptation and species longevity, and its primary function is in sexual signaling and species recognition.

  6. Marine Microbial Secondary Metabolites: Pathways, Evolution and Physiological Roles.

    PubMed

    Giordano, Daniela; Coppola, Daniela; Russo, Roberta; Denaro, Renata; Giuliano, Laura; Lauro, Federico M; di Prisco, Guido; Verde, Cinzia

    2015-01-01

    Microbes produce a huge array of secondary metabolites endowed with important ecological functions. These molecules, which can be catalogued as natural products, have long been exploited in medical fields as antibiotics, anticancer and anti-infective agents. Recent years have seen considerable advances in elucidating natural-product biosynthesis and many drugs used today are natural products or natural-product derivatives. The major contribution to recent knowledge came from application of genomics to secondary metabolism and was facilitated by all relevant genes being organised in a contiguous DNA segment known as gene cluster. Clustering of genes regulating biosynthesis in bacteria is virtually universal. Modular gene clusters can be mixed and matched during evolution to generate structural diversity in natural products. Biosynthesis of many natural products requires the participation of complex molecular machines known as polyketide synthases and non-ribosomal peptide synthetases. Discovery of new evolutionary links between the polyketide synthase and fatty acid synthase pathways may help to understand the selective advantages that led to evolution of secondary-metabolite biosynthesis within bacteria. Secondary metabolites confer selective advantages, either as antibiotics or by providing a chemical language that allows communication among species, with other organisms and their environment. Herewith, we discuss these aspects focusing on the most clinically relevant bioactive molecules, the thiotemplated modular systems that include polyketide synthases, non-ribosomal peptide synthetases and fatty acid synthases. We begin by describing the evolutionary and physiological role of marine natural products, their structural/functional features, mechanisms of action and biosynthesis, then turn to genomic and metagenomic approaches, highlighting how the growing body of information on microbial natural products can be used to address fundamental problems in

  7. Developmental integration of feather growth and pigmentation and its implications for the evolution of diet-derived coloration.

    PubMed

    Landeen, Elizabeth A; Badyaev, Alexander V

    2012-01-15

    Variation in avian coloration is produced by coordinated pigmentation of thousands of growing feathers that vary in shape and size. Although the functional consequences of avian coloration are frequently studied, little is known about its developmental basis, and, specifically, the rules that link feather growth to pigment uptake and synthesis. Here, we combine biochemical, modeling, and morphometric techniques to examine the developmental basis of feather pigmentation in house finches (Carpodacus mexicanus)--a species with extensive variation in both growth dynamics of ornamental feathers and their carotenoid pigmentation. We found that the rate of carotenoid uptake was constant across a wide range of feather sizes and shapes, and the relative pigmented area of feathers was independent of the total amount of deposited carotenoids. Analysis of the developmental linkage of feather growth and pigment uptake showed that the mechanisms behind partitioning the feather into pigmented and nonpigmented parts and the mechanisms regulating carotenoid uptake into growing feathers are partially independent. Carotenoid uptake strongly covaried with early elements of feather differentiation (the barb addition rate and diameter), whereas the pigmented area was most closely associated with the rate of feather growth. We suggest that strong effects of carotenoid uptake on genetically integrated mechanisms of feather growth and differentiation provide a likely route for genetic assimilation of diet-dependent coloration.

  8. Monascus pigments.

    PubMed

    Feng, Yanli; Shao, Yanchun; Chen, Fusheng

    2012-12-01

    Monascus pigments (MPs) as natural food colorants have been widely utilized in food industries in the world, especially in China and Japan. Moreover, MPs possess a range of biological activities, such as anti-mutagenic and anticancer properties, antimicrobial activities, potential anti-obesity activities, and so on. So, in the past two decades, more and more attention has been paid to MPs. Up to now, more than 50 MPs have been identified and studied. However, there have been some reviews about red fermented rice and the secondary metabolites produced by Monascus, but no monograph or review of MPs has been published. This review covers the categories and structures, biosynthetic pathway, production, properties, detection methods, functions, and molecular biology of MPs.

  9. Evolution of oxytocin pathways in the brain of vertebrates

    PubMed Central

    Knobloch, H. Sophie; Grinevich, Valery

    2014-01-01

    The central oxytocin system transformed tremendously during the evolution, thereby adapting to the expanding properties of species. In more basal vertebrates (paraphyletic taxon Anamnia, which includes agnathans, fish and amphibians), magnocellular neurosecretory neurons producing homologs of oxytocin reside in the wall of the third ventricle of the hypothalamus composing a single hypothalamic structure, the preoptic nucleus. This nucleus further diverged in advanced vertebrates (monophyletic taxon Amniota, which includes reptiles, birds, and mammals) into the paraventricular and supraoptic nuclei with accessory nuclei (AN) between them. The individual magnocellular neurons underwent a process of transformation from primitive uni- or bipolar neurons into highly differentiated neurons. Due to these microanatomical and cytological changes, the ancient release modes of oxytocin into the cerebrospinal fluid were largely replaced by vascular release. However, the most fascinating feature of the progressive transformations of the oxytocin system has been the expansion of oxytocin axonal projections to forebrain regions. In the present review we provide a background on these evolutionary advancements. Furthermore, we draw attention to the non-synaptic axonal release in small and defined brain regions with the aim to clearly distinguish this way of oxytocin action from the classical synaptic transmission on one side and from dendritic release followed by a global diffusion on the other side. Finally, we will summarize the effects of oxytocin and its homologs on pro-social reproductive behaviors in representatives of the phylogenetic tree and will propose anatomically plausible pathways of oxytocin release contributing to these behaviors in basal vertebrates and amniots. PMID:24592219

  10. cis-Regulatory changes in Kit ligand expression and parallel evolution of pigmentation in sticklebacks and humans.

    PubMed

    Miller, Craig T; Beleza, Sandra; Pollen, Alex A; Schluter, Dolph; Kittles, Rick A; Shriver, Mark D; Kingsley, David M

    2007-12-14

    Dramatic pigmentation changes have evolved within most vertebrate groups, including fish and humans. Here we use genetic crosses in sticklebacks to investigate the parallel origin of pigmentation changes in natural populations. High-resolution mapping and expression experiments show that light gills and light ventrums map to a divergent regulatory allele of the Kit ligand (Kitlg) gene. The divergent allele reduces expression in gill and skin tissue and is shared by multiple derived freshwater populations with reduced pigmentation. In humans, Europeans and East Asians also share derived alleles at the KITLG locus. Strong signatures of selection map to regulatory regions surrounding the gene, and admixture mapping shows that the KITLG genomic region has a significant effect on human skin color. These experiments suggest that regulatory changes in Kitlg contribute to natural variation in vertebrate pigmentation, and that similar genetic mechanisms may underlie rapid evolutionary change in fish and humans.

  11. Genetic Architecture of Abdominal Pigmentation in Drosophila melanogaster

    PubMed Central

    Dembeck, Lauren M.; Huang, Wen; Magwire, Michael M.; Lawrence, Faye; Lyman, Richard F.; Mackay, Trudy F. C.

    2015-01-01

    Pigmentation varies within and between species and is often adaptive. The amount of pigmentation on the abdomen of Drosophila melanogaster is a relatively simple morphological trait, which serves as a model for mapping the genetic basis of variation in complex phenotypes. Here, we assessed natural variation in female abdominal pigmentation in 175 sequenced inbred lines of the Drosophila melanogaster Genetic Reference Panel, derived from the Raleigh, NC population. We quantified the proportion of melanization on the two most posterior abdominal segments, tergites 5 and 6 (T5, T6). We found significant genetic variation in the proportion of melanization and high broad-sense heritabilities for each tergite. Genome-wide association studies identified over 150 DNA variants associated with the proportion of melanization on T5 (84), T6 (34), and the difference between T5 and T6 (35). Several of the top variants associated with variation in pigmentation are in tan, ebony, and bric-a-brac1, genes known to affect D. melanogaster abdominal pigmentation. Mutational analyses and targeted RNAi-knockdown showed that 17 out of 28 (61%) novel candidate genes implicated by the genome-wide association study affected abdominal pigmentation. Several of these genes are involved in developmental and regulatory pathways, chitin production, cuticle structure, and vesicle formation and transport. These findings show that genetic variation may affect multiple steps in pathways involved in tergite development and melanization. Variation in these novel candidates may serve as targets for adaptive evolution and sexual selection in D. melanogaster. PMID:25933381

  12. Genetic Architecture of Abdominal Pigmentation in Drosophila melanogaster.

    PubMed

    Dembeck, Lauren M; Huang, Wen; Magwire, Michael M; Lawrence, Faye; Lyman, Richard F; Mackay, Trudy F C

    2015-05-01

    Pigmentation varies within and between species and is often adaptive. The amount of pigmentation on the abdomen of Drosophila melanogaster is a relatively simple morphological trait, which serves as a model for mapping the genetic basis of variation in complex phenotypes. Here, we assessed natural variation in female abdominal pigmentation in 175 sequenced inbred lines of the Drosophila melanogaster Genetic Reference Panel, derived from the Raleigh, NC population. We quantified the proportion of melanization on the two most posterior abdominal segments, tergites 5 and 6 (T5, T6). We found significant genetic variation in the proportion of melanization and high broad-sense heritabilities for each tergite. Genome-wide association studies identified over 150 DNA variants associated with the proportion of melanization on T5 (84), T6 (34), and the difference between T5 and T6 (35). Several of the top variants associated with variation in pigmentation are in tan, ebony, and bric-a-brac1, genes known to affect D. melanogaster abdominal pigmentation. Mutational analyses and targeted RNAi-knockdown showed that 17 out of 28 (61%) novel candidate genes implicated by the genome-wide association study affected abdominal pigmentation. Several of these genes are involved in developmental and regulatory pathways, chitin production, cuticle structure, and vesicle formation and transport. These findings show that genetic variation may affect multiple steps in pathways involved in tergite development and melanization. Variation in these novel candidates may serve as targets for adaptive evolution and sexual selection in D. melanogaster.

  13. Photosynthetic Pigments in Diatoms

    PubMed Central

    Kuczynska, Paulina; Jemiola-Rzeminska, Malgorzata; Strzalka, Kazimierz

    2015-01-01

    Photosynthetic pigments are bioactive compounds of great importance for the food, cosmetic, and pharmaceutical industries. They are not only responsible for capturing solar energy to carry out photosynthesis, but also play a role in photoprotective processes and display antioxidant activity, all of which contribute to effective biomass and oxygen production. Diatoms are organisms of a distinct pigment composition, substantially different from that present in plants. Apart from light-harvesting pigments such as chlorophyll a, chlorophyll c, and fucoxanthin, there is a group of photoprotective carotenoids which includes β-carotene and the xanthophylls, diatoxanthin, diadinoxanthin, violaxanthin, antheraxanthin, and zeaxanthin, which are engaged in the xanthophyll cycle. Additionally, some intermediate products of biosynthetic pathways have been identified in diatoms as well as unusual pigments, e.g., marennine. Marine algae have become widely recognized as a source of unique bioactive compounds for potential industrial, pharmaceutical, and medical applications. In this review, we summarize current knowledge on diatom photosynthetic pigments complemented by some new insights regarding their physico-chemical properties, biological role, and biosynthetic pathways, as well as the regulation of pigment level in the cell, methods of purification, and significance in industries. PMID:26389924

  14. Photosynthetic Pigments in Diatoms.

    PubMed

    Kuczynska, Paulina; Jemiola-Rzeminska, Malgorzata; Strzalka, Kazimierz

    2015-09-16

    Photosynthetic pigments are bioactive compounds of great importance for the food, cosmetic, and pharmaceutical industries. They are not only responsible for capturing solar energy to carry out photosynthesis, but also play a role in photoprotective processes and display antioxidant activity, all of which contribute to effective biomass and oxygen production. Diatoms are organisms of a distinct pigment composition, substantially different from that present in plants. Apart from light-harvesting pigments such as chlorophyll a, chlorophyll c, and fucoxanthin, there is a group of photoprotective carotenoids which includes β-carotene and the xanthophylls, diatoxanthin, diadinoxanthin, violaxanthin, antheraxanthin, and zeaxanthin, which are engaged in the xanthophyll cycle. Additionally, some intermediate products of biosynthetic pathways have been identified in diatoms as well as unusual pigments, e.g., marennine. Marine algae have become widely recognized as a source of unique bioactive compounds for potential industrial, pharmaceutical, and medical applications. In this review, we summarize current knowledge on diatom photosynthetic pigments complemented by some new insights regarding their physico-chemical properties, biological role, and biosynthetic pathways, as well as the regulation of pigment level in the cell, methods of purification, and significance in industries.

  15. Benzoquinone from Fusarium pigment inhibits the proliferation of estrogen receptor-positive MCF-7 cells through the NF-κB pathway via estrogen receptor signaling

    PubMed Central

    Zheng, Lixiang; Cai, Yujian; Zhou, Li; Huang, Ping; Ren, Xiaoying; Zuo, Airen; Meng, Xianming; Xu, Minjuan; Liao, Xiangru

    2017-01-01

    Natural pigments are known for possessing a wide range of pharmacological and health-promoting properties. The pigments, produced by a new strain Fusarium (Fusarium sp. JN158) previously identified in our laboratory, were found to have 6 peaks (representing 6 compounds) by high-performance liquid chromatography with a diode-array detector (HPLC-DAD) separation. The 6th peak compound (compound VI) is a benzoquinone compound. In this study, we examined the effects of compound VI on the proliferation of breast cancer cells and aimed to elucidate the underlying mechamisms. Compound VI exerted anti-proliferative effects on MCF-7 estrogen receptor (ER)+ cells in a dose-dependent manner (IC25, 7 µM; IC50, 11 µM), whereas it had no effect on MDA-MB-231 ER− cells and normal cells. The cell index (CI) began to decrease at 24 h following treatment with benzoquinone. Mechanistically, the results from molecular analysis revealed that compound VI inhibited the expression of ERα, progesterone receptor (PR), vascular endothelial growth factor (VEGF), Bcl-2, cyclin D1 and nuclear factor-κB (NF-κB) p65, while it increased the expression of cleaved caspase-3 and Bax in the MCF-7 cells. Taken together, our findings indicate that compound VI exerts anti-proliferative effects on MCF-7 cells through the NF-κB pathway via the regulation of ER signaling. Our data may indicate that benzoquinone from Fusarium pigment may have potential for use as an anti-proliferative agent in the treatment of breast cancer. PMID:27878233

  16. Effects of glucose on sorbitol pathway activation, cellular redox, and metabolism of myo-inositol, phosphoinositide, and diacylglycerol in cultured human retinal pigment epithelial cells.

    PubMed Central

    Thomas, T P; Porcellati, F; Kato, K; Stevens, M J; Sherman, W R; Greene, D A

    1994-01-01

    Sorbitol (aldose reductase) pathway flux in diabetes perturbs intracellular metabolism by two putative mechanisms: reciprocal osmoregulatory depletion of other organic osmolytes e.g., myo-inositol, and alterations in NADPH/NADP+ and/or NADH/NAD+. The "osmolyte" and "redox" hypotheses predict secondary elevations in CDP-diglyceride, the rate-limiting precursor for phosphatidylinositol synthesis, but through different mechanisms: the "osmolyte" hypothesis via depletion of intracellular myo-inositol (the cosubstrate for phosphatidylinositol-synthase) and the "redox" hypothesis through enhanced de novo synthesis from triose phosphates. The osmolyte hypothesis predicts diminished phosphoinositide-derived arachidonyl-diacylglycerol, while the redox hypothesis predicts increased total diacylglycerol and phosphatidic acid. In high aldose reductase expressing retinal pigment epithelial cells, glucose-induced, aldose reductase inhibitor-sensitive CDP-diglyceride accumulation and inhibition of 32P-incorporation into phosphatidylinositol paralleled myo-inositol depletion (but not cytoplasmic redox, that was unaffected by glucose) and depletion of arachidonyl-diacylglycerol. 3 mM pyruvate added to the culture medium left cellular redox unaltered, but stimulated Na(+)-dependent myo-inositol uptake, accumulation, and incorporation into phosphatidylinositol. These results favor myo-inositol depletion rather than altered redox as the primary cause of glucose-induced aldose reductase-related defects in phospholipid metabolism in cultured retinal pigment epithelial cells. Images PMID:8201009

  17. BioPAXViz: a cytoscape application for the visual exploration of metabolic pathway evolution.

    PubMed

    Psomopoulos, Fotis E; Vitsios, Dimitrios M; Baichoo, Shakuntala; Ouzounis, Christos A

    2017-01-25

    BioPAXViz is a Cytoscape (version 3) application, providing a comprehensive framework for metabolic pathway visualization. Beyond the basic parsing, viewing and browsing roles, the main novel function that BioPAXViz provides is a visual comparative analysis of metabolic pathway topologies across pre-computed pathway phylogenomic profiles given a species phylogeny. Furthermore, BioPAXViz supports the display of hierarchical trees that allow efficient navigation through sets of variants of a single reference pathway. Thus, BioPAXViz can significantly facilitate, and contribute to, the study of metabolic pathway evolution and engineering.

  18. A polymorphism in IRF4 affects human pigmentation through a tyrosinase-dependent MITF/TFAP2A pathway

    PubMed Central

    Praetorius, Christian; Grill, Christine; Stacey, Simon N.; Metcalf, Alexander M.; Gorkin, David U.; Robinson, Kathleen C.; Van Otterloo, Eric; Kim, Reuben S.Q.; Bergsteinsdottir, Kristin; Ogmundsdottir, Margret H.; Magnusdottir, Erna; Mishra, Pravin J.; Davis, Sean R.; Guo, Theresa; Zaidi, M. Raza; Helgason, Agnar S.; Sigurdsson, Martin I.; Melzer, Paul S.; Merlino, Glenn; Petit, Valerie; Larue, Lionel; Loftus, Stacie K.; Adams, David R.; Sobhiafshar, Ulduz; Emre, N. C. Tolga; Pavan, William J.; Cornell, Robert; Smith, Aaron G.; McCallion, Andrew S.; Fisher, David E.; Stefansson, Kari; Sturm, Richard A.; Steingrímsson, Eiríkur

    2013-01-01

    Sequence polymorphisms linked to human diseases and phenotypes in genome-wide association studies often affect non-coding regions. A single nucleotide polymorphism (SNP) within an intron of the gene encoding Interferon Regulatory Factor 4 (IRF4), a transcription factor with no known role in melanocyte biology, is strongly associated with sensitivity of skin to sun exposure, freckles, blue eyes and brown hair color. Here we demonstrate that this SNP lies within an enhancer of IRF4 transcription in melanocytes. The allele associated with this pigmentation phenotype impairs binding of the TFAP2A transcription factor which together with the melanocyte master regulator MITF, regulates activity of the enhancer. Assays in zebrafish and mice reveal that IRF4 cooperates with MITF to activate expression of Tyrosinase (TYR), an essential enzyme in melanin synthesis. Our findings provide a clear example of a non-coding polymorphism that affects a phenotype by modulating a developmental gene regulatory network. PMID:24267888

  19. Illumination from light-emitting diodes (LEDs) disrupts pathological cytokines expression and activates relevant signal pathways in primary human retinal pigment epithelial cells.

    PubMed

    Shen, Ye; Xie, Chen; Gu, Yangshun; Li, Xiuyi; Tong, Jianping

    2016-04-01

    Age-related macular degeneration (AMD) is the leading cause of blindness in the aged people. The latest systemic review of epidemiological investigations revealed that excessive light exposure increases the risk of AMD. With the drastically increasing use of high-energy light-emitting diodes (LEDs) light in our domestic environment nowadays, it is supposed to pose a potential oxidative threat to ocular health. Retinal pigment epithelium (RPE) is the major ocular source of pathological cytokines, which regulate local inflammation and angiogenesis. We hypothesized that high-energy LED light might disrupt the pathological cytokine expression of retinal pigment epithelium (RPE), contributing to the pathogenesis of AMD. Primary human RPE cells were isolated from eyecups of normal eye donors and seeded into plate wells for growing to confluence. Two widely used multichromatic white light-emitting diodes (LEDs) with correlated color temperatures (CCTs) of 2954 and 7378 K were used in this experiment. The confluent primary RPE cells were under white LEDs light exposure until 24 h. VEGF-A, IL-6, IL-8 and MCP-1 proteins and mRNAs were measured using an ELISA kit and RT-PCR, respectively. Activation of mitogen-activated protein kinases (MAPKs), Akt, Janus kinase (JAK)2 and Nuclear factor (NF)-κB signal pathways after LEDs illumination were evaluated by western blotting analysis. The level of reactive oxygen species (ROS) using chloromethyl- 2',7'-dichlorodihydrofluorescein diacetate. Inhibitors of relevant signal pathways and anti-oxidants were added to the primary RPE cells before LEDs illumination to evaluate their biological functions. We found that 7378 K light, but not 2954 K upregulated the VEGF-A, IL-6, IL-8 and downregulated MCP-1 proteins and mRNAs levels in a time-dependent manner. In parallel, initial activation of MAPKs and NF-κB signal pathways were also observed after 7378 K light exposure. Mechanistically, antioxidants for eliminating reactive oxygen

  20. Evolution of the isoprene biosynthetic pathway in kudzu.

    PubMed

    Sharkey, Thomas D; Yeh, Sansun; Wiberley, Amy E; Falbel, Tanya G; Gong, Deming; Fernandez, Donna E

    2005-02-01

    Isoprene synthase converts dimethylallyl diphosphate, derived from the methylerythritol 4-phosphate (MEP) pathway, to isoprene. Isoprene is made by some plants in substantial amounts, which affects atmospheric chemistry, while other plants make no isoprene. As part of our long-term study of isoprene synthesis, the genetics of the isoprene biosynthetic pathway of the isoprene emitter, kudzu (Pueraria montana), was compared with similar genes in Arabidopsis (Arabidopsis thaliana), which does not make isoprene. The MEP pathway genes in kudzu were similar to the corresponding Arabidopsis genes. Isoprene synthase genes of kudzu and aspen (Populus tremuloides) were cloned to compare their divergence with the divergence seen in MEP pathway genes. Phylogenetic analysis of the terpene synthase gene family indicated that isoprene synthases are either within the monoterpene synthase clade or sister to it. In Arabidopsis, the gene most similar to isoprene synthase is a myrcene/ocimene (acyclic monoterpenes) synthase. Two phenylalanine residues found exclusively in isoprene synthases make the active site smaller than other terpene synthase enzymes, possibly conferring specificity for the five-carbon substrate rather than precursors of the larger isoprenoids. Expression of the kudzu isoprene synthase gene in Arabidopsis caused Arabidopsis to emit isoprene, indicating that whether or not a plant emits isoprene depends on whether or not it has a terpene synthase capable of using dimethylallyl diphosphate.

  1. Possible role of HIWI2 in modulating tight junction proteins in retinal pigment epithelial cells through Akt signaling pathway.

    PubMed

    Sivagurunathan, Suganya; Palanisamy, Karthikka; Arunachalam, Jayamuruga Pandian; Chidambaram, Subbulakshmi

    2017-03-01

    PIWI subfamily of proteins is shown to be primarily expressed in germline cells. They maintain the genomic integrity by silencing the transposable elements. Although the role of PIWI proteins in germ cells has been documented, their presence and function in somatic cells remains unclear. Intriguingly, we detected all four members of PIWI-like proteins in human ocular tissues and somatic cell lines. When HIWI2 was knocked down in retinal pigment epithelial cells, the typical honeycomb morphology was affected. Further analysis showed that the expression of tight junction (TJ) proteins, CLDN1, and TJP1 were altered in HIWI2 knockdown. Moreover, confocal imaging revealed disrupted TJP1 assembly at the TJ. Previous studies report the role of GSK3β in regulating TJ proteins. Accordingly, phospho-kinase proteome profiler array indicated increased phosphorylation of Akt and GSK3α/β in HIWI2 knockdown, suggesting that HIWI2 might affect TJ proteins through Akt-GSK3α/β signaling axis. Moreover, treating the HIWI2 knockdown cells with wortmannin increased the levels of TJP1 and CLDN1. Taken together, our study demonstrates the presence of PIWI-like proteins in somatic cells and the possible role of HIWI2 in preserving the functional integrity of epithelial cells probably by modulating the phosphorylation status of Akt.

  2. The secretory pathway of protists: spatial and functional organization and evolution.

    PubMed Central

    Becker, B; Melkonian, M

    1996-01-01

    All cells secrete a diversity of macromolecules to modify their environment or to protect themselves. Eukaryotic cells have evolved a complex secretory pathway consisting of several membrane-bound compartments which contain specific sets of proteins. Experimental work on the secretory pathway has focused mainly on mammalian cell lines or on yeasts. Now, some general principles of the secretory pathway have become clear, and most components of the secretory pathway are conserved between yeast cells and mammalian cells. However, the structure and function of the secretory system in protists have been less extensively studied. In this review, we summarize the current knowledge about the secretory pathway of five different groups of protists: Giardia lamblia, one of the earliest lines of eukaryotic evolution, kinetoplastids, the slime mold Dictyostelium discoideum, and two lineages within the "crown" of eukaryotic cell evolution, the alveolates (ciliates and Plasmodium species) and the green algae. Comparison of these systems with the mammalian and yeast system shows that most elements of the secretory pathway were presumably present in the earliest eukaryotic organisms. However, one element of the secretory pathway shows considerable variation: the presence of a Golgi stack and the number of cisternae within a stack. We suggest that the functional separation of the plasma membrane from the nucleus-endoplasmic reticulum system during evolution required a sorting compartment, which became the Golgi apparatus. Once a Golgi apparatus was established, it was adapted to the various needs of the different organisms. PMID:8987360

  3. TGF-{beta}-stimulated aberrant expression of class III {beta}-tubulin via the ERK signaling pathway in cultured retinal pigment epithelial cells

    SciTech Connect

    Chung, Eun Jee; Chun, Ji Na; Jung, Sun-Ah; Cho, Jin Won; Lee, Joon H.

    2011-11-18

    Highlights: Black-Right-Pointing-Pointer TGF-{beta} induces aberrant expression of {beta}III in RPE cells via the ERK pathway. Black-Right-Pointing-Pointer TGF-{beta} increases O-GlcNAc modification of {beta}III in RPE cells. Black-Right-Pointing-Pointer Mature RPE cells have the capacity to express a neuron-associated gene by TGF-{beta}. -- Abstract: The class III {beta}-tubulin isotype ({beta}{sub III}) is expressed exclusively by neurons within the normal human retina and is not present in normal retinal pigment epithelial (RPE) cells in situ or in the early phase of primary cultures. However, aberrant expression of class III {beta}-tubulin has been observed in passaged RPE cells and RPE cells with dedifferentiated morphology in pathologic epiretinal membranes from idiopathic macular pucker, proliferative vitreoretinopathy (PVR) and proliferative diabetic retinopathy (PDR). Transforming growth factor-{beta} (TGF-{beta}) has been implicated in dedifferentiation of RPE cells and has a critical role in the development of proliferative vitreoretinal diseases. Here, we investigated the potential effects of TGF-{beta} on the aberrant expression of class III {beta}-tubulin and the intracellular signaling pathway mediating these changes. TGF-{beta}-induced aberrant expression and O-linked-{beta}-N-acetylglucosamine (O-GlcNac) modification of class III {beta}-tubulin in cultured RPE cells as determined using Western blotting, RT-PCR and immunocytochemistry. TGF-{beta} also stimulated phosphorylation of ERK. TGF-{beta}-induced aberrant expression of class III {beta}-tubulin was significantly reduced by pretreatment with U0126, an inhibitor of ERK phosphorylation. Our findings indicate that TGF-{beta} stimulated aberrant expression of class III {beta}-tubulin via activation of the ERK signaling pathway. These data demonstrate that mature RPE cells have the capacity to express a neuron-associated gene in response to TGF-{beta} stimulation and provide useful information

  4. Diversity and Evolution of the Phenazine Biosynthesis Pathway ▿ †

    PubMed Central

    Mavrodi, Dmitri V.; Peever, Tobin L.; Mavrodi, Olga V.; Parejko, James A.; Raaijmakers, Jos M.; Lemanceau, Philippe; Mazurier, Sylvie; Heide, Lutz; Blankenfeldt, Wulf; Weller, David M.; Thomashow, Linda S.

    2010-01-01

    Phenazines are versatile secondary metabolites of bacterial origin that function in biological control of plant pathogens and contribute to the ecological fitness and pathogenicity of the producing strains. In this study, we employed a collection of 94 strains having various geographic, environmental, and clinical origins to study the distribution and evolution of phenazine genes in members of the genera Pseudomonas, Burkholderia, Pectobacterium, Brevibacterium, and Streptomyces. Our results confirmed the diversity of phenazine producers and revealed that most of them appear to be soil-dwelling and/or plant-associated species. Genome analyses and comparisons of phylogenies inferred from sequences of the key phenazine biosynthesis (phzF) and housekeeping (rrs, recA, rpoB, atpD, and gyrB) genes revealed that the evolution and dispersal of phenazine genes are driven by mechanisms ranging from conservation in Pseudomonas spp. to horizontal gene transfer in Burkholderia spp. and Pectobacterium spp. DNA extracted from cereal crop rhizospheres and screened for the presence of phzF contained sequences consistent with the presence of a diverse population of phenazine producers in commercial farm fields located in central Washington state, which provided the first evidence of United States soils enriched in indigenous phenazine-producing bacteria. PMID:20008172

  5. Origin and evolution of the Notch signalling pathway: an overview from eukaryotic genomes

    PubMed Central

    Gazave, Eve; Lapébie, Pascal; Richards, Gemma S; Brunet, Frédéric; Ereskovsky, Alexander V; Degnan, Bernard M; Borchiellini, Carole; Vervoort, Michel; Renard, Emmanuelle

    2009-01-01

    Background Of the 20 or so signal transduction pathways that orchestrate cell-cell interactions in metazoans, seven are involved during development. One of these is the Notch signalling pathway which regulates cellular identity, proliferation, differentiation and apoptosis via the developmental processes of lateral inhibition and boundary induction. In light of this essential role played in metazoan development, we surveyed a wide range of eukaryotic genomes to determine the origin and evolution of the components and auxiliary factors that compose and modulate this pathway. Results We searched for 22 components of the Notch pathway in 35 different species that represent 8 major clades of eukaryotes, performed phylogenetic analyses and compared the domain compositions of the two fundamental molecules: the receptor Notch and its ligands Delta/Jagged. We confirm that a Notch pathway, with true receptors and ligands is specific to the Metazoa. This study also sheds light on the deep ancestry of a number of genes involved in this pathway, while other members are revealed to have a more recent origin. The origin of several components can be accounted for by the shuffling of pre-existing protein domains, or via lateral gene transfer. In addition, certain domains have appeared de novo more recently, and can be considered metazoan synapomorphies. Conclusion The Notch signalling pathway emerged in Metazoa via a diversity of molecular mechanisms, incorporating both novel and ancient protein domains during eukaryote evolution. Thus, a functional Notch signalling pathway was probably present in Urmetazoa. PMID:19825158

  6. Molecular and developmental contributions to divergent pigment patterns in marine and freshwater sticklebacks.

    PubMed

    Greenwood, Anna K; Cech, Jennifer N; Peichel, Catherine L

    2012-07-01

    Pigment pattern variation across species or populations offers a tractable framework in which to investigate the evolution of development. Juvenile threespine sticklebacks (Gasterosteus aculeatus) from marine and freshwater environments exhibit divergent pigment patterns that are associated with ecological differences. Juvenile marine sticklebacks have a silvery appearance, whereas sticklebacks from freshwater environments exhibit a pattern of vertical bars. We investigated both the developmental and molecular basis of this population-level variation in pigment pattern. Time course imaging during the transition from larval to juvenile stages revealed differences between marine and freshwater fish in spatial patterns of chromatophore differentiation as well as in pigment amount and dispersal. In freshwater fish, melanophores appear primarily within dark bars whereas iridophores appear within light bars. By contrast, in marine fish, these chromatophores are interspersed across the flank. In addition to spatially segregated chromatophore differentiation, pigment amount and dispersal within melanophores varies spatially across the flank of freshwater, but not marine fish. To gain insight into the molecular pathways that underlie the differences in pigment pattern development, we evaluated differential gene expression in the flanks of developing fish using high-throughput cDNA sequencing (RNA-seq) and quantitative PCR. We identified several genes that were differentially expressed across dark and light bars of freshwater fish, and between freshwater and marine fish. Together, these experiments begin to shed light on the process of pigment pattern evolution in sticklebacks.

  7. Diversity of bile salts in fish and amphibians: evolution of a complex biochemical pathway.

    PubMed

    Hagey, Lee R; Møller, Peter R; Hofmann, Alan F; Krasowski, Matthew D

    2010-01-01

    Bile salts are the major end metabolites of cholesterol and are also important in lipid and protein digestion, as well as shaping of the gut microflora. Previous studies had demonstrated variation of bile salt structures across vertebrate species. We greatly extend prior surveys of bile salt variation in fish and amphibians, particularly in analysis of the biliary bile salts of Agnatha and Chondrichthyes. While there is significant structural variation of bile salts across all fish orders, bile salt profiles are generally stable within orders of fish and do not correlate with differences in diet. This large data set allowed us to infer evolutionary changes in the bile salt synthetic pathway. The hypothesized ancestral bile salt synthetic pathway, likely exemplified in extant hagfish, is simpler and much shorter than the pathway of most teleost fish and terrestrial vertebrates. Thus, the bile salt synthetic pathway has become longer and more complex throughout vertebrate evolution. Analysis of the evolution of bile salt synthetic pathways provides a rich model system for the molecular evolution of a complex biochemical pathway in vertebrates.

  8. Evolution of macromolecular import pathways in mitochondria, hydrogenosomes and mitosomes.

    PubMed

    Lithgow, Trevor; Schneider, André

    2010-03-12

    All eukaryotes require mitochondria for survival and growth. The origin of mitochondria can be traced down to a single endosymbiotic event between two probably prokaryotic organisms. Subsequent evolution has left mitochondria a collection of heterogeneous organelle variants. Most of these variants have retained their own genome and translation system. In hydrogenosomes and mitosomes, however, the entire genome was lost. All types of mitochondria import most of their proteome from the cytosol, irrespective of whether they have a genome or not. Moreover, in most eukaryotes, a variable number of tRNAs that are required for mitochondrial translation are also imported. Thus, import of macromolecules, both proteins and tRNA, is essential for mitochondrial biogenesis. Here, we review what is known about the evolutionary history of the two processes using a recently revised eukaryotic phylogeny as a framework. We discuss how the processes of protein import and tRNA import relate to each other in an evolutionary context.

  9. Stepwise evolution of the centriole-assembly pathway.

    PubMed

    Carvalho-Santos, Zita; Machado, Pedro; Branco, Pedro; Tavares-Cadete, Filipe; Rodrigues-Martins, Ana; Pereira-Leal, José B; Bettencourt-Dias, Mónica

    2010-05-01

    The centriole and basal body (CBB) structure nucleates cilia and flagella, and is an essential component of the centrosome, underlying eukaryotic microtubule-based motility, cell division and polarity. In recent years, components of the CBB-assembly machinery have been identified, but little is known about their regulation and evolution. Given the diversity of cellular contexts encountered in eukaryotes, but the remarkable conservation of CBB morphology, we asked whether general mechanistic principles could explain CBB assembly. We analysed the distribution of each component of the human CBB-assembly machinery across eukaryotes as a strategy to generate testable hypotheses. We found an evolutionarily cohesive and ancestral module, which we term UNIMOD and is defined by three components (SAS6, SAS4/CPAP and BLD10/CEP135), that correlates with the occurrence of CBBs. Unexpectedly, other players (SAK/PLK4, SPD2/CEP192 and CP110) emerged in a taxon-specific manner. We report that gene duplication plays an important role in the evolution of CBB components and show that, in the case of BLD10/CEP135, this is a source of tissue specificity in CBB and flagella biogenesis. Moreover, we observe extreme protein divergence amongst CBB components and show experimentally that there is loss of cross-species complementation among SAK/PLK4 family members, suggesting species-specific adaptations in CBB assembly. We propose that the UNIMOD theory explains the conservation of CBB architecture and that taxon- and tissue-specific molecular innovations, gained through emergence, duplication and divergence, play important roles in coordinating CBB biogenesis and function in different cellular contexts.

  10. Directed evolution of a cellobiose utilization pathway in Saccharomyces cerevisiae by simultaneously engineering multiple proteins

    PubMed Central

    2013-01-01

    Background The optimization of metabolic pathways is critical for efficient and economical production of biofuels and specialty chemicals. One such significant pathway is the cellobiose utilization pathway, identified as a promising route in biomass utilization. Here we describe the optimization of cellobiose consumption and ethanol productivity by simultaneously engineering both proteins of the pathway, the β-glucosidase (gh1-1) and the cellodextrin transporter (cdt-1), in an example of pathway engineering through directed evolution. Results The improved pathway was assessed based on the strain specific growth rate on cellobiose, with the final mutant exhibiting a 47% increase over the wild-type pathway. Metabolite analysis of the engineered pathway identified a 49% increase in cellobiose consumption (1.78 to 2.65 g cellobiose/(L · h)) and a 64% increase in ethanol productivity (0.611 to 1.00 g ethanol/(L · h)). Conclusions By simultaneously engineering multiple proteins in the pathway, cellobiose utilization in S. cerevisiae was improved. This optimization can be generally applied to other metabolic pathways, provided a selection/screening method is available for the desired phenotype. The improved in vivo cellobiose utilization demonstrated here could help to decrease the in vitro enzyme load in biomass pretreatment, ultimately contributing to a reduction in the high cost of biofuel production. PMID:23802545

  11. Molecular evolution of multiple-level control of heme biosynthesis pathway in animal kingdom.

    PubMed

    Tzou, Wen-Shyong; Chu, Ying; Lin, Tzung-Yi; Hu, Chin-Hwa; Pai, Tun-Wen; Liu, Hsin-Fu; Lin, Han-Jia; Cases, Ildeofonso; Rojas, Ana; Sanchez, Mayka; You, Zong-Ye; Hsu, Ming-Wei

    2014-01-01

    Adaptation of enzymes in a metabolic pathway can occur not only through changes in amino acid sequences but also through variations in transcriptional activation, mRNA splicing and mRNA translation. The heme biosynthesis pathway, a linear pathway comprised of eight consecutive enzymes in animals, provides researchers with ample information for multiple types of evolutionary analyses performed with respect to the position of each enzyme in the pathway. Through bioinformatics analysis, we found that the protein-coding sequences of all enzymes in this pathway are under strong purifying selection, from cnidarians to mammals. However, loose evolutionary constraints are observed for enzymes in which self-catalysis occurs. Through comparative genomics, we found that in animals, the first intron of the enzyme-encoding genes has been co-opted for transcriptional activation of the genes in this pathway. Organisms sense the cellular content of iron, and through iron-responsive elements in the 5' untranslated regions of mRNAs and the intron-exon boundary regions of pathway genes, translational inhibition and exon choice in enzymes may be enabled, respectively. Pathway product (heme)-mediated negative feedback control can affect the transport of pathway enzymes into the mitochondria as well as the ubiquitin-mediated stability of enzymes. Remarkably, the positions of these controls on pathway activity are not ubiquitous but are biased towards the enzymes in the upstream portion of the pathway. We revealed that multiple-level controls on the activity of the heme biosynthesis pathway depend on the linear depth of the enzymes in the pathway, indicating a new strategy for discovering the molecular constraints that shape the evolution of a metabolic pathway.

  12. Evolution of pigment-dispersing factor neuropeptides in Panarthropoda: Insights from Onychophora (velvet worms) and Tardigrada (water bears).

    PubMed

    Mayer, Georg; Hering, Lars; Stosch, Juliane M; Stevenson, Paul A; Dircksen, Heinrich

    2015-09-01

    Pigment-dispersing factor (PDF) denotes a conserved family of homologous neuropeptides present in several invertebrate groups, including mollusks, nematodes, insects, and crustaceans (referred to here as pigment-dispersing hormone [PDH]). With regard to their encoding genes (pdf, pdh), insects possess only one, nematodes two, and decapod crustaceans up to three, but their phylogenetic relationship is unknown. To shed light on the origin and diversification of pdf/pdh homologs in Panarthropoda (Onychophora + Tardigrada + Arthropoda) and other molting animals (Ecdysozoa), we analyzed the transcriptomes of five distantly related onychophorans and a representative tardigrade and searched for putative pdf homologs in publically available genomes of other protostomes. This revealed only one pdf homolog in several mollusk and annelid species; two in Onychophora, Priapulida, and Nematoda; and three in Tardigrada. Phylogenetic analyses suggest that the last common ancestor of Panarthropoda possessed two pdf homologs, one of which was lost in the arthropod or arthropod/tardigrade lineage, followed by subsequent duplications of the remaining homolog in some taxa. Immunolocalization of PDF-like peptides in six onychophoran species, by using a broadly reactive antibody that recognizes PDF/PDH peptides in numerous species, revealed an elaborate system of neurons and fibers in their central and peripheral nervous systems. Large varicose projections in the heart suggest that the PDF neuropeptides functioned as both circulating hormones and locally released transmitters in the last common ancestor of Onychophora and Arthropoda. The lack of PDF-like-immunoreactive somata associated with the onychophoran optic ganglion conforms to the hypothesis that onychophoran eyes are homologous to the arthropod median ocelli.

  13. Iris phenotypes and pigment dispersion caused by genes influencing pigmentation.

    PubMed

    Anderson, Michael G; Hawes, Norman L; Trantow, Colleen M; Chang, Bo; John, Simon W M

    2008-10-01

    Spontaneous mutations altering mouse coat colors have been a classic resource for discovery of numerous molecular pathways. Although often overlooked, the mouse iris is also densely pigmented and easily observed, thus representing a similarly powerful opportunity for studying pigment cell biology. Here, we present an analysis of iris phenotypes among 16 mouse strains with mutations influencing melanosomes. Many of these strains exhibit biologically and medically relevant phenotypes, including pigment dispersion, a common feature of several human ocular diseases. Pigment dispersion was identified in several strains with mutant alleles known to influence melanosomes, including beige, light, and vitiligo. Pigment dispersion was also detected in the recently arising spontaneous coat color variant, nm2798. We have identified the nm2798 mutation as a missense mutation in the Dct gene, an identical re-occurrence of the slaty light mutation. These results suggest that dysregulated events of melanosomes can be potent contributors to the pigment dispersion phenotype. Combined, these findings illustrate the utility of studying iris phenotypes as a means of discovering new pathways, and re-linking old ones, to processes of pigmented cells in health and disease.

  14. Lycopene inhibits PDGF-BB-induced retinal pigment epithelial cell migration by suppression of PI3K/Akt and MAPK pathways

    SciTech Connect

    Chan, Chi-Ming; Fang, Jia-You; Lin, Hsin-Huang; Yang, Chi-Yea; Hung, Chi-Feng

    2009-10-09

    Retinal pigment epithelial (RPE) cells play a dominant role in the development of proliferative vitreoretinopathy (PVR), which is the leading cause of failure in retinal reattachment surgery. Several studies have shown that platelet-derived growth factor (PDGF) exhibits chemotaxis and proliferation effects on RPE cells in PVR. In this study, the inhibitory effect of lycopene on PDGF-BB-induced ARPE19 cell migration is examined. In electric cell-substrate impedance sensing (ECIS) and Transwell migration assays, significant suppression of PDGF-BB-induced ARPE19 cell migration by lycopene is observed. Cell viability assays show no cytotoxicity of lycopene on RPE cells. Lycopene shows no effect on ARPE19 cell adhesion and is found to inhibit PDGF-BB-induced tyrosine phosphorylation and the underlying signaling pathways of PI3K, Akt, ERK and p38 activation. However, PDGF-BB and lycopene show no effects on JNK activation. Taken together, our results demonstrate that lycopene inhibits PDGF-BB-induced ARPE19 cell migration through inhibition of PI3K/Akt, ERK and p38 activation.

  15. MicroRNA-184 promotes differentiation of the retinal pigment epithelium by targeting the AKT2/mTOR signaling pathway

    PubMed Central

    Jiang, Chao; Qin, Bing; Liu, Guohua; Sun, Xiantao; Shi, Houxia; Ding, Sijia; Liu, Yuan; Zhu, Meidong; Chen, Xue; Zhao, Chen

    2016-01-01

    Dedifferentiation of retinal pigment epithelium (RPE) cells is a crucial contributing factor to the pathology of retinal degenerative diseases, including age-related macular degeneration (AMD). Herein, we aim to reveal the roles of microRNAs (miRNAs) in RPE dedifferentiation and seek for potential therapeutic targets. Based on the microarray data, miR-184 was sorted out as the most up-regulated signature along with the differentiation from human induced pluripotent stem cells (hiPSC) to RPE cells, suggesting its potential promotive role in RPE differentiation. In vitro study indicated that miR-184 insufficiency suppressed RPE differentiation, typified by reduction of RPE markers, and promoted cell proliferation and migration. The role of miR-184 in maintaining regular RPE function was further proved in zebrafish studies. We also noticed that miR-184 expression was reduced in the macular RPE-choroid from a donor with RPE dysfunction compared to a healthy control. We next demonstrated that RAC-beta serine/threonine-protein kinase (AKT2) was a direct target for miR-184. MiR-184 promoted RPE differentiation via suppression of AKT2/mammalian target of rapamycin (mTOR) signaling pathway. We also found that AKT2 was up-regulated in macular RPE-choroid of the donor with RPE dysfunction and dry AMD patients. Taken together, our findings suggest that miR-184 insufficiency is involved in the pathogenesis of dry AMD. MiR-184 promotes RPE differentiation via inhibiting the AKT2/mTOR signaling pathway. MiR-184 based supplementary therapeutics and mTOR blocker, like rapamycin, are prospective options for AMD treatment. PMID:27418134

  16. Pigment epithelium-derived factor has a role in the progression of papillary thyroid carcinoma by affecting the HIF1α-VEGF signaling pathway

    PubMed Central

    Lv, Yichen; Sun, Yu; Shi, Tiefeng; Shi, Chenlei; Qin, Huadong; Li, Zhaozhu

    2016-01-01

    The progression mechanism of papillary thyroid carcinoma (PTC) remains largely unknown. Accumulating evidence has suggested that various targets of pigment epithelium-derived factor (PEDF) are able to inhibit cancer progression. The aim of the present study was to examine PEDF expression in PTC patients and to investigate its relationship with aggressive clinicopathological features, as well as to explore whether PEDF affects the progression of PTC via the hypoxia-inducible factor 1α (HIF1α)-vascular endothelial growth factor (VEGF) pathway. A total of 271 patients with PTC, including 24 men and 247 women, were enrolled in the present study. Relevant patient data, including demographic features, preoperative clinical features and pathological features, were collected for analysis. The protein expression levels of PEDF in PTC tissues were detected using immunohistochemical staining, and the mRNA expression levels of PEDF, VEGF and HIF1α in 15 PTC tissues with lymph node metastasis (LNM) and 10 tissues without LNM were detected using reverse transcription-quantitative polymerase chain reaction. Immunohistochemical staining with an anti-PEDF antibody detected PEDF expression in 74.5% of the PTC tissues. PEDF expression levels were significantly correlated with LNM, extrathyroid invasion, a high TNM stage, the presence of the BRAFV600E mutation and tumor size. PEDF mRNA expression levels were significantly decreased in PTC tissues with LNM, as compared with PTC tissues without LNM, while the mRNA expression levels of HIF1α and VEGF were markedly increased in PTC tissues with LNM. Taken together, the results of the present study suggested that PEDF plays a role in the progression of PTC, and that PEDF may exert an anti-angiogenesis role by affecting the HIF1α-VEGF pathway, eventually inhibiting the metastasis of PTC. PMID:28105231

  17. SLC29A3 gene is mutated in pigmented hypertrichosis with insulin-dependent diabetes mellitus syndrome and interacts with the insulin signaling pathway.

    PubMed

    Cliffe, Simon T; Kramer, Jamie M; Hussain, Khalid; Robben, Joris H; de Jong, Eiko K; de Brouwer, Arjan P; Nibbeling, Esther; Kamsteeg, Erik-Jan; Wong, Melanie; Prendiville, Julie; James, Chela; Padidela, Raja; Becknell, Charlie; van Bokhoven, Hans; Deen, Peter M T; Hennekam, Raoul C M; Lindeman, Robert; Schenck, Annette; Roscioli, Tony; Buckley, Michael F

    2009-06-15

    Pigmented hypertrichotic dermatosis with insulin-dependent diabetes (PHID) syndrome is a recently described autosomal recessive disorder associated with predominantly antibody negative, insulin-dependent diabetes mellitus. In order to identify the genetic basis of PHID and study its relationship with glucose metabolism, we performed homozygosity mapping in five unrelated families followed by candidate gene sequencing. Five loss-of-function mutations were identified in the SLC29A3 gene which encodes a member of a highly conserved protein family that transports nucleosides, nucleobases and nucleoside analogue drugs, hENT3. We show that PHID is allelic with a related syndrome without diabetes mellitus, H syndrome. The interaction of SLC29A3 with insulin signaling pathways was then studied using an established model in Drosophila melanogaster. Ubiquitous knockdown of the Drosophila ortholog of hENT3, dENT1 is lethal under stringent conditions; whereas milder knockdown induced scutellar bristle phenotypes similar to those previously reported in the knockdown of the Drosophila ortholog of the Islet gene. A cellular growth assay showed a reduction of cell size/number which could be rescued or enhanced by manipulation of the Drosophila insulin receptor and its downstream signaling effectors, dPI3K and dAkt. In summary, inactivating mutations in SLC29A3 cause a syndromic form of insulin-dependent diabetes in humans and in Drosophila profoundly affect cell size/number through interactions with the insulin signaling pathway. These data suggest that further investigation of the role of SLC29A3 in glucose metabolism is a priority for diabetes research.

  18. Evidence from Biochemical Pathways in Favor of Unfinished Evolution Rather than Intelligent Design

    ERIC Educational Resources Information Center

    Behrman, Edward J.; Marzluf, George A.

    2004-01-01

    An argument is made in favor of imperfect or unfinished evolution based on some metabolic pathways in which it seems that intelligent design would have done better. The case studies noted indicate the absence of highly intelligent design and are not intended as comprehensive collection but as a limited sample of inefficient situations in…

  19. Evolution of a new chlorophyll metabolic pathway driven by the dynamic changes in enzyme promiscuous activity.

    PubMed

    Ito, Hisashi; Tanaka, Ayumi

    2014-03-01

    Organisms generate an enormous number of metabolites; however, the mechanisms by which a new metabolic pathway is acquired are unknown. To elucidate the importance of promiscuous enzyme activity for pathway evolution, the catalytic and substrate specificities of Chl biosynthetic enzymes were examined. In green plants, Chl a and Chl b are interconverted by the Chl cycle: Chl a is hydroxylated to 7-hydroxymethyl chlorophyll a followed by the conversion to Chl b, and both reactions are catalyzed by chlorophyllide a oxygenase. Chl b is reduced to 7-hydroxymethyl chlorophyll a by Chl b reductase and then converted to Chl a by 7-hydroxymethyl chlorophyll a reductase (HCAR). A phylogenetic analysis indicated that HCAR evolved from cyanobacterial 3,8-divinyl chlorophyllide reductase (DVR), which is responsible for the reduction of an 8-vinyl group in the Chl biosynthetic pathway. In addition to vinyl reductase activity, cyanobacterial DVR also has Chl b reductase and HCAR activities; consequently, three of the four reactions of the Chl cycle already existed in cyanobacteria, the progenitor of the chloroplast. During the evolution of cyanobacterial DVR to HCAR, the HCAR activity, a promiscuous reaction of cyanobacterial DVR, became the primary reaction. Moreover, the primary reaction (vinyl reductase activity) and some disadvantageous reactions were lost, but the neutral promiscuous reaction (NADH dehydrogenase) was retained in both DVR and HCAR. We also show that a portion of the Chl c biosynthetic pathway already existed in cyanobacteria. We discuss the importance of dynamic changes in promiscuous activity and of the latent pathways for metabolic evolution.

  20. Evolution of arthropod visual systems: development of the eyes and central visual pathways in the horseshoe crab Limulus polyphemus Linnaeus, 1758 (Chelicerata, Xiphosura).

    PubMed

    Harzsch, Steffen; Vilpoux, Kathia; Blackburn, David C; Platchetzki, David; Brown, Nadean L; Melzer, Roland; Kempler, Karen E; Battelle, Barbara A

    2006-10-01

    Despite ongoing interest into the architecture, biochemistry, and physiology of the visual systems of the xiphosuran Limulus polyphemus, their ontogenetic aspects have received little attention. Thus, we explored the development of the lateral eyes and associated neuropils in late embryos and larvae of these animals. The first external evidence of the lateral eyes was the appearance of white pigment spots-guanophores associated with the rudimentary photoreceptors-on the dorsolateral side of the late embryos, suggesting that these embryos can perceive light. The first brown pigment emerges in the eyes during the last (third) embryonic molt to the trilobite stage. However, ommatidia develop from this field of pigment toward the end of the larval trilobite stage so that the young larvae at hatching do not have object recognition. Double staining with the proliferation marker bromodeoxyuridine (BrdU) and an antibody against L. polyphemus myosin III, which is concentrated in photoreceptors of this species, confirmed previous reports that, in the trilobite larvae, new cellular material is added to the eye field from an anteriorly located proliferation zone. Pulse-chase experiments indicated that these new cells differentiate into new ommatidia. Examining larval eyes labeled for opsin showed that the new ommatidia become organized into irregular rows that give the eye field a triangular appearance. Within the eye field, the ommatidia are arranged in an imperfect hexagonal array. Myosin III immunoreactivity in trilobite larvae also revealed the architecture of the central visual pathways associated with the median eye complex and the lateral eyes. Double labeling with myosin III and BrdU showed that neurogenesis persists in the larval brain and suggested that new neurons of both the lamina and the medulla originate from a single common proliferation zone. These data are compared with eye development in Drosophila melanogaster and are discussed with regard to new ideas on

  1. Making new molecules - evolution of pathways for novel metabolites in plants.

    PubMed

    Kliebenstein, Daniel J; Osbourn, Anne

    2012-08-01

    Plants have adapted to their environments by diversifying in various ways. This diversification is reflected at the phytochemical level in their production of numerous specialized secondary metabolites that provide protection against biotic and abiotic stresses. Plant speciation is therefore intimately linked to metabolic diversification, yet we do not currently have a deep understanding of how new metabolic pathways evolve. Recent evidence indicates that genes for individual secondary metabolic pathways can be either distributed throughout the genome or clustered, but the relative frequencies of these two pathway organizations remain to be established. While it is possible that clustering is a feature of pathways that have evolved in recent evolutionary time, the answer to this and how dispersed and clustered pathways may be related remain to be addressed. Recent advances enabled by genomics and systems biology are beginning to yield the first insights into network evolution in plant metabolism. This review focuses on recent progress in understanding the evolution of clustered and dispersed pathways for new secondary metabolites in plants.

  2. Mechanism of riboflavin uptake by cultured human retinal pigment epithelial ARPE-19 cells: possible regulation by an intracellular Ca2+-calmodulin-mediated pathway.

    PubMed

    Said, Hamid M; Wang, Shuling; Ma, Thomas Y

    2005-07-15

    In mammalian cells (including those of the ocular system), the water-soluble vitamin B2 (riboflavin, RF) assumes an essential role in a variety of metabolic reactions and is critical for normal cellular functions, growth and development. Cells of the human retinal pigment epithelium (hRPE) play an important role in providing a sufficient supply of RF to the retina, but nothing is known about the mechanism of the vitamin uptake by these cells and its regulation. Our aim in the present study was to address this issue using the hRPE ARPE-19 cells as the retinal epithelial model. Our results show RF uptake in the hRPE to be: (1) energy and temperature dependent and occurring without metabolic alteration in the transported substrate, (2) pH but not Na+ dependent, (3) saturable as a function of concentration with an apparent Km of 80 +/- 14 nM, (4) trans-stimulated by unlabelled RF and its structural analogue lumiflavine, (5) cis-inhibited by the RF structural analogues lumiflavine and lumichrome but not by unrelated compounds, and (6) inhibited by the anion transport inhibitors 4,4'-diisothiocyanatostilbene-2,2'-disulphonic acid (DIDS) and 4-acetamido-4'-isothiocyanatostilbene-2,2'-disulphonic acid (SITS) as well as by the Na+ -H+ exchange inhibitor amiloride and the sulfhydryl group inhibitor p-chloromercuriphenylsulphonate (p-CMPS). Maintaining the hRPE cells in a RF-deficient medium led to a specific and significant up-regulation in RF uptake which was mediated via changes in the number and affinity of the RF uptake carriers. While modulating the activities of intracellular protein kinase A (PKA)-, protein kinase C (PKC)-, protein tyrosine kinase (PTK)-, and nitric oxide (NO)-mediated pathways were found to have no role in regulating RF uptake, a role for the Ca2+ -calmodulin-mediated pathway was observed. These studies demonstrate for the first time the involvement of a specialized carrier-mediated mechanism for RF uptake by hRPE cells and show that the process is

  3. Evolution of alternative biosynthetic pathways for vitamin C following plastid acquisition in photosynthetic eukaryotes.

    PubMed

    Wheeler, Glen; Ishikawa, Takahiro; Pornsaksit, Varissa; Smirnoff, Nicholas

    2015-03-13

    Ascorbic acid (vitamin C) is an enzyme co-factor in eukaryotes that also plays a critical role in protecting photosynthetic eukaryotes against damaging reactive oxygen species derived from the chloroplast. Many animal lineages, including primates, have become ascorbate auxotrophs due to the loss of the terminal enzyme in their biosynthetic pathway, L-gulonolactone oxidase (GULO). The alternative pathways found in land plants and Euglena use a different terminal enzyme, L-galactonolactone dehydrogenase (GLDH). The evolutionary processes leading to these differing pathways and their contribution to the cellular roles of ascorbate remain unclear. Here we present molecular and biochemical evidence demonstrating that GULO was functionally replaced with GLDH in photosynthetic eukaryote lineages following plastid acquisition. GULO has therefore been lost repeatedly throughout eukaryote evolution. The formation of the alternative biosynthetic pathways in photosynthetic eukaryotes uncoupled ascorbate synthesis from hydrogen peroxide production and likely contributed to the rise of ascorbate as a major photoprotective antioxidant.

  4. Red Algal Phylogenomics Provides a Robust Framework for Inferring Evolution of Key Metabolic Pathways

    PubMed Central

    Qiu, Huan; Yoon, Hwan Su; Bhattacharya, Debashish

    2016-01-01

    Red algae comprise an anciently diverged, species-rich phylum with morphologies that span unicells to large seaweeds. Here, leveraging a rich red algal genome and transcriptome dataset, we used 298 single-copy orthologous nuclear genes from 15 red algal species to erect a robust multi-gene phylogeny of Rhodophyta. This tree places red seaweeds (Bangiophyceae and Florideophyceae) at the base of the mesophilic red algae with the remaining non-seaweed mesophilic lineages forming a well-supported sister group. The early divergence of seaweeds contrasts with the evolution of multicellular land plants and brown algae that are nested among multiple, unicellular or filamentous sister lineages. Using this novel perspective on red algal evolution, we studied the evolution of the pathways for isoprenoid biosynthesis. This analysis revealed losses of the mevalonate pathway on at least three separate occasions in lineages that contain Cyanidioschyzon, Porphyridium, and Chondrus. Our results establish a framework for in-depth studies of the origin and evolution of genes and metabolic pathways in Rhodophyta. PMID:28018750

  5. On the levels of enzymatic substrate specificity: Implications for the early evolution of metabolic pathways

    NASA Technical Reports Server (NTRS)

    Lazcano, A.; Diaz-Villagomez, E.; Mills, T.; Oro, J.

    1995-01-01

    The most frequently invoked explanation for the origin of metabolic pathways is the retrograde evolution hypothesis. In contrast, according to the so-called 'patchwork' theory, metabolism evolved by the recruitment of relatively inefficient small enzymes of broad specificity that could react with a wide range of chemically related substrates. In this paper it is argued that both sequence comparisons and experimental results on enzyme substrate specificity support the patchwork assembly theory. The available evidence supports previous suggestions that gene duplication events followed by a gradual neoDarwinian accumulation of mutations and other minute genetic changes lead to the narrowing and modification of enzyme function in at least some primordial metabolic pathways.

  6. Human skin pigmentation as an adaptation to UV radiation

    PubMed Central

    Jablonski, Nina G.; Chaplin, George

    2010-01-01

    Human skin pigmentation is the product of two clines produced by natural selection to adjust levels of constitutive pigmentation to levels of UV radiation (UVR). One cline was generated by high UVR near the equator and led to the evolution of dark, photoprotective, eumelanin-rich pigmentation. The other was produced by the requirement for UVB photons to sustain cutaneous photosynthesis of vitamin D3 in low-UVB environments, and resulted in the evolution of depigmented skin. As hominins dispersed outside of the tropics, they experienced different intensities and seasonal mixtures of UVA and UVB. Extreme UVA throughout the year and two equinoctial peaks of UVB prevail within the tropics. Under these conditions, the primary selective pressure was to protect folate by maintaining dark pigmentation. Photolysis of folate and its main serum form of 5-methylhydrofolate is caused by UVR and by reactive oxygen species generated by UVA. Competition for folate between the needs for cell division, DNA repair, and melanogenesis is severe under stressful, high-UVR conditions and is exacerbated by dietary insufficiency. Outside of tropical latitudes, UVB levels are generally low and peak only once during the year. The populations exhibiting maximally depigmented skin are those inhabiting environments with the lowest annual and summer peak levels of UVB. Development of facultative pigmentation (tanning) was important to populations settling between roughly 23° and 46° , where levels of UVB varied strongly according to season. Depigmented and tannable skin evolved numerous times in hominin evolution via independent genetic pathways under positive selection. PMID:20445093

  7. The role of log-normal dynamics in the evolution of biochemical pathways.

    PubMed

    Nacher, J C; Ochiai, T; Yamada, T; Kanehisa, M; Akutsu, T

    2006-01-01

    The study of the scale-free topology in non-biological and biological networks and the dynamics that can explain this fascinating property of complex systems have captured the attention of the scientific community in the last years. Here, we analyze the biochemical pathways of three organisms (Methanococcus jannaschii, Escherichia coli, Saccharomyces cerevisiae) which are representatives of the main kingdoms Archaea, Bacteria and Eukaryotes during the course of the biological evolution. We can consider two complementary representations of the biochemical pathways: the enzymes network and the chemical compounds network. In this article, we propose a stochastic model that explains that the scale-free topology with exponent in the vicinity of gamma approximately 3/2 found across these three organisms is governed by the log-normal dynamics in the evolution of the enzymes network. Precisely, the fluctuations of the connectivity degree of enzymes in the biochemical pathways between evolutionary distant organisms follow the same conserved dynamical principle, which in the end is the origin of the stationary scale-free distribution observed among species, from Archaea to Eukaryotes. In particular, the log-normal dynamics guarantees the conservation of the scale-free distribution in evolving networks. Furthermore, the log-normal dynamics also gives a possible explanation for the restricted range of observed exponents gamma in the scale-free networks (i.e., gamma > or = 3/2). Finally, our model is also applied to the chemical compounds network of biochemical pathways and the Internet network.

  8. The etiology and molecular genetics of human pigmentation disorders

    PubMed Central

    Baxter, Laura L.; Pavan, William J.

    2012-01-01

    Pigmentation, defined as the placement of pigment in skin, hair, and eyes for coloration, is distinctive because the location, amount, and type of pigmentation provides a visual manifestation of genetic heterogeneity in pathways regulating the pigment-producing cells, melanocytes. The scope of this genetic heterogeneity in humans ranges from normal to pathological pigmentation phenotypes. Clinically normal human pigmentation encompasses a variety of skin and hair color as well as with punctate pigmentation such as melanocytic nevi (moles) or ephelides (freckles), while clinically abnormal human pigmentation exhibits markedly reduced or increased pigment levels, known as hypopigmentation and hyperpigmentation, respectively. Elucidation of the molecular genetics underlying pigmentation has revealed genes important for melanocyte development and function. Furthermore, many pigmentation disorders show additional defects in cells other than melanocytes, and identification of the genetic insults in these disorders has revealed pleiotropic genes, where a single gene is required for various functions, often in different cell types. Thus unravelling the genetics of easily visualized pigmentation disorders has identified molecular similarities between melanocytes and less visible cell types/tissues, revealing a common cellular origin and/or common genetic regulatory pathways. Herein we discuss notable human pigmentation disorders and their associated genetic alterations, focusing on the fact that the developmental genetics of pigmentation abnormalities is instructive for understanding normal pathways governing development and function of melanocytes. PMID:23799582

  9. Phylogenetic analyses of termite post-embryonic sequences illuminate caste and developmental pathway evolution.

    PubMed

    Legendre, Frédéric; Whiting, Michael F; Grandcolas, Philippe

    2013-01-01

    Termites are highly eusocial insects with a caste polyphenism (i.e., discontinuous morphological differences between castes) and elaborated behaviors. While the developmental pathways leading to caste occurrence are well-known in many species, the evolutionary origin of these pathways is still obscure. Recent molecular phylogenetic studies suggest multiple independent origins of sterile castes in termites, reviving a 30 years old debate. We demonstrate here that diploid sterile castes ("true" workers) evolved several times independently in this group and that this caste was lost at least once in a lineage with developmentally more flexible workers called pseudergates or "false" workers. We also infer that flexibility in post-embryonic development was acquired multiple times independently during termite evolution. We suggest that focusing on detailed developmental pathways in phylogenetic analyses is essential for elucidating the origin of caste polyphenism in termites.

  10. Comparison of human cell signaling pathway databases—evolution, drawbacks and challenges

    PubMed Central

    Chowdhury, Saikat; Sarkar, Ram Rup

    2015-01-01

    Elucidating the complexities of cell signaling pathways is of immense importance to gain understanding about various biological phenomenon, such as dynamics of gene/protein expression regulation, cell fate determination, embryogenesis and disease progression. The successful completion of human genome project has also helped experimental and theoretical biologists to analyze various important pathways. To advance this study, during the past two decades, systematic collections of pathway data from experimental studies have been compiled and distributed freely by several databases, which also integrate various computational tools for further analysis. Despite significant advancements, there exist several drawbacks and challenges, such as pathway data heterogeneity, annotation, regular update and automated image reconstructions, which motivated us to perform a thorough review on popular and actively functioning 24 cell signaling databases. Based on two major characteristics, pathway information and technical details, freely accessible data from commercial and academic databases are examined to understand their evolution and enrichment. This review not only helps to identify some novel and useful features, which are not yet included in any of the databases but also highlights their current limitations and subsequently propose the reasonable solutions for future database development, which could be useful to the whole scientific community. PMID:25632107

  11. A toolbox model of evolution of metabolic pathways on networks of arbitrary topology.

    PubMed

    Pang, Tin Yau; Maslov, Sergei

    2011-05-01

    In prokaryotic genomes the number of transcriptional regulators is known to be proportional to the square of the total number of protein-coding genes. A toolbox model of evolution was recently proposed to explain this empirical scaling for metabolic enzymes and their regulators. According to its rules, the metabolic network of an organism evolves by horizontal transfer of pathways from other species. These pathways are part of a larger "universal" network formed by the union of all species-specific networks. It remained to be understood, however, how the topological properties of this universal network influence the scaling law of functional content of genomes in the toolbox model. Here we answer this question by first analyzing the scaling properties of the toolbox model on arbitrary tree-like universal networks. We prove that critical branching topology, in which the average number of upstream neighbors of a node is equal to one, is both necessary and sufficient for quadratic scaling. We further generalize the rules of the model to incorporate reactions with multiple substrates/products as well as branched and cyclic metabolic pathways. To achieve its metabolic tasks, the new model employs evolutionary optimized pathways with minimal number of reactions. Numerical simulations of this realistic model on the universal network of all reactions in the KEGG database produced approximately quadratic scaling between the number of regulated pathways and the size of the metabolic network. To quantify the geometrical structure of individual pathways, we investigated the relationship between their number of reactions, byproducts, intermediate, and feedback metabolites. Our results validate and explain the ubiquitous appearance of the quadratic scaling for a broad spectrum of topologies of underlying universal metabolic networks. They also demonstrate why, in spite of "small-world" topology, real-life metabolic networks are characterized by a broad distribution of pathway

  12. The evolution of microRNA pathway protein components in Cnidaria.

    PubMed

    Moran, Yehu; Praher, Daniela; Fredman, David; Technau, Ulrich

    2013-12-01

    In the last decade, it became evident that posttranscriptional regulation of gene expression by microRNAs is a central biological process in both plants and animals. Yet, our knowledge about microRNA biogenesis and utilization in animals stems mostly from the study of Bilateria. In this study, we identified genes encoding the protein components of different parts of the microRNA pathway in Cnidaria, the likely sister phylum of Bilateria. These genes originated from three cnidarian lineages (sea anemones, stony corals, and hydras) that are separated by at least 500 My from one another. We studied the expression and phylogeny of the cnidarian homologs of Drosha and Pasha (DGCR8) that compose the microprocessor, the RNAse III enzyme Dicer and its partners, the HEN1 methyltransferase, the Argonaute protein effectors, as well as members of the GW182 protein family. We further reveal that whereas the bilaterian dicer partners Loquacious/TRBP and PACT are absent from Cnidaria, this phylum contains homologs of the double-stranded RNA-binding protein HYL1, the Dicer partner found in plants. We also identified HYL1 homologs in a sponge and a ctenophore. This finding raises questions regarding the independent evolution of the microRNA pathway in plants and animals, and together with the other results shed new light on the evolution of an important regulatory pathway.

  13. Rapid evolution of piRNA pathway in the teleost fish: implication for an adaptation to transposon diversity.

    PubMed

    Yi, Minhan; Chen, Feng; Luo, Majing; Cheng, Yibin; Zhao, Huabin; Cheng, Hanhua; Zhou, Rongjia

    2014-05-19

    The Piwi-interacting RNA (piRNA) pathway is responsible for germline specification, gametogenesis, transposon silencing, and genome integrity. Transposable elements can disrupt genome and its functions. However, piRNA pathway evolution and its adaptation to transposon diversity in the teleost fish remain unknown. This article unveils evolutionary scene of piRNA pathway and its association with diverse transposons by systematically comparative analysis on diverse teleost fish genomes. Selective pressure analysis on piRNA pathway and miRNA/siRNA (microRNA/small interfering RNA) pathway genes between teleosts and mammals showed an accelerated evolution of piRNA pathway genes in the teleost lineages, and positive selection on functional PAZ (Piwi/Ago/Zwille) and Tudor domains involved in the Piwi-piRNA/Tudor interaction, suggesting that the amino acid substitutions are adaptive to their functions in piRNA pathway in the teleost fish species. Notably five piRNA pathway genes evolved faster in the swamp eel, a kind of protogynous hermaphrodite fish, than the other teleosts, indicating a differential evolution of piRNA pathway between the swamp eel and other gonochoristic fishes. In addition, genome-wide analysis showed higher diversity of transposons in the teleost fish species compared with mammals. Our results suggest that rapidly evolved piRNA pathway in the teleost fish is likely to be involved in the adaption to transposon diversity.

  14. Skin Pigmentation Disorders

    MedlinePlus

    Pigmentation means coloring. Skin pigmentation disorders affect the color of your skin. Your skin gets its color from a pigment called melanin. Special cells in the skin make melanin. When these cells become damaged or ...

  15. Solid State Pathways to Complex Shape Evolution and Tunable Porosity during Metallic Crystal Growth

    PubMed Central

    Valenzuela, Carlos Díaz; Carriedo, Gabino A.; Valenzuela, María L.; Zúñiga, Luis; O'Dwyer, Colm

    2013-01-01

    Growing complex metallic crystals, supported high index facet nanocrystal composites and tunable porosity metals, and exploiting factors that influence shape and morphology is crucial in many exciting developments in chemistry, catalysis, biotechnology and nanoscience. Assembly, organization and ordered crystallization of nanostructures into complex shapes requires understanding of the building blocks and their association, and this relationship can define the many physical properties of crystals and their assemblies. Understanding crystal evolution pathways is required for controlled deposition onto surfaces. Here, complex metallic crystals on the nano- and microscale, carbon supported nanoparticles, and spinodal porous noble metals with defined inter-feature distances in 3D, are accomplished in the solid-state for Au, Ag, Pd, and Re. Bottom-up growth and positioning is possible through competitive coarsening of mobile nanoparticles and their site-specific crystallization in a nucleation-dewetted matrix. Shape evolution, density and growth mechanism of complex metallic crystals and porous metals can be imaged during growth. PMID:24026532

  16. The oestrogen pathway underlies the evolution of exaggerated male cranial shapes in Anolis lizards

    PubMed Central

    Sanger, Thomas J.; Seav, Susan M.; Tokita, Masayoshi; Langerhans, R. Brian; Ross, Lela M.; Losos, Jonathan B.; Abzhanov, Arhat

    2014-01-01

    Sexual dimorphisms vary widely among species. This variation must arise through sex-specific evolutionary modifications to developmental processes. Anolis lizards vary extensively in their expression of cranial dimorphism. Compared with other Anolis species, members of the carolinensis clade have evolved relatively high levels of cranial dimorphism; males of this clade have exceptionally long faces relative to conspecific females. Developmentally, this facial length dimorphism arises through an evolutionarily novel, clade-specific strategy. Our analyses herein reveal that sex-specific regulation of the oestrogen pathway underlies evolution of this exaggerated male phenotype, rather than the androgen or insulin growth factor pathways that have long been considered the primary regulators of male-biased dimorphism among vertebrates. Our results suggest greater intricacy in the genetic mechanisms that underlie sexual dimorphisms than previously appreciated. PMID:24741020

  17. The oestrogen pathway underlies the evolution of exaggerated male cranial shapes in Anolis lizards.

    PubMed

    Sanger, Thomas J; Seav, Susan M; Tokita, Masayoshi; Langerhans, R Brian; Ross, Lela M; Losos, Jonathan B; Abzhanov, Arhat

    2014-06-07

    Sexual dimorphisms vary widely among species. This variation must arise through sex-specific evolutionary modifications to developmental processes. Anolis lizards vary extensively in their expression of cranial dimorphism. Compared with other Anolis species, members of the carolinensis clade have evolved relatively high levels of cranial dimorphism; males of this clade have exceptionally long faces relative to conspecific females. Developmentally, this facial length dimorphism arises through an evolutionarily novel, clade-specific strategy. Our analyses herein reveal that sex-specific regulation of the oestrogen pathway underlies evolution of this exaggerated male phenotype, rather than the androgen or insulin growth factor pathways that have long been considered the primary regulators of male-biased dimorphism among vertebrates. Our results suggest greater intricacy in the genetic mechanisms that underlie sexual dimorphisms than previously appreciated.

  18. Evolution of the EGFR pathway in Metazoa and its diversification in the planarian Schmidtea mediterranea

    PubMed Central

    Barberán, Sara; Martín-Durán, José M.; Cebrià, Francesc

    2016-01-01

    The EGFR pathway is an essential signaling system in animals, whose core components are the epidermal growth factors (EGF ligands) and their trans-membrane tyrosine kinase receptors (EGFRs). Despite extensive knowledge in classical model organisms, little is known of the composition and function of the EGFR pathway in most animal lineages. Here, we have performed an extensive search for the presence of EGFRs and EGF ligands in representative species of most major animal clades, with special focus on the planarian Schmidtea mediterranea. With the exception of placozoans and cnidarians, we found that the EGFR pathway is potentially present in all other analyzed animal groups, and has experienced frequent independent expansions. We further characterized the expression domains of the EGFR/EGF identified in S. mediterranea, revealing a wide variety of patterns and localization in almost all planarian tissues. Finally, functional experiments suggest an interaction between one of the previously described receptors, Smed-egfr-5, and the newly found ligand Smed-egf-6. Our findings provide the most comprehensive overview to date of the EGFR pathway, and indicate that the last common metazoan ancestor had an initial complement of one EGFR and one putative EGF ligand, which was often expanded or lost during animal evolution. PMID:27325311

  19. Evolution of the EGFR pathway in Metazoa and its diversification in the planarian Schmidtea mediterranea.

    PubMed

    Barberán, Sara; Martín-Durán, José M; Cebrià, Francesc

    2016-06-21

    The EGFR pathway is an essential signaling system in animals, whose core components are the epidermal growth factors (EGF ligands) and their trans-membrane tyrosine kinase receptors (EGFRs). Despite extensive knowledge in classical model organisms, little is known of the composition and function of the EGFR pathway in most animal lineages. Here, we have performed an extensive search for the presence of EGFRs and EGF ligands in representative species of most major animal clades, with special focus on the planarian Schmidtea mediterranea. With the exception of placozoans and cnidarians, we found that the EGFR pathway is potentially present in all other analyzed animal groups, and has experienced frequent independent expansions. We further characterized the expression domains of the EGFR/EGF identified in S. mediterranea, revealing a wide variety of patterns and localization in almost all planarian tissues. Finally, functional experiments suggest an interaction between one of the previously described receptors, Smed-egfr-5, and the newly found ligand Smed-egf-6. Our findings provide the most comprehensive overview to date of the EGFR pathway, and indicate that the last common metazoan ancestor had an initial complement of one EGFR and one putative EGF ligand, which was often expanded or lost during animal evolution.

  20. Evolution of alternative biosynthetic pathways for vitamin C following plastid acquisition in photosynthetic eukaryotes

    PubMed Central

    Wheeler, Glen; Ishikawa, Takahiro; Pornsaksit, Varissa; Smirnoff, Nicholas

    2015-01-01

    Ascorbic acid (vitamin C) is an enzyme co-factor in eukaryotes that also plays a critical role in protecting photosynthetic eukaryotes against damaging reactive oxygen species derived from the chloroplast. Many animal lineages, including primates, have become ascorbate auxotrophs due to the loss of the terminal enzyme in their biosynthetic pathway, l-gulonolactone oxidase (GULO). The alternative pathways found in land plants and Euglena use a different terminal enzyme, l-galactonolactone dehydrogenase (GLDH). The evolutionary processes leading to these differing pathways and their contribution to the cellular roles of ascorbate remain unclear. Here we present molecular and biochemical evidence demonstrating that GULO was functionally replaced with GLDH in photosynthetic eukaryote lineages following plastid acquisition. GULO has therefore been lost repeatedly throughout eukaryote evolution. The formation of the alternative biosynthetic pathways in photosynthetic eukaryotes uncoupled ascorbate synthesis from hydrogen peroxide production and likely contributed to the rise of ascorbate as a major photoprotective antioxidant. DOI: http://dx.doi.org/10.7554/eLife.06369.001 PMID:25768426

  1. Simulation of permeability evolution of leakage pathway in carbonate-rich caprocks in carbon sequestration

    NASA Astrophysics Data System (ADS)

    Guo, B.; Fitts, J. P.; Dobossy, M. E.; Peters, C. A.

    2013-12-01

    Geologic carbon sequestration in deep saline aquifers is a promising strategy for mitigating climate change. A major concern is the possibility of brine and CO2 migration through the caprock such as through fractures and faults. In this work, we examine the extent to which mineral dissolution will substantially alter the porosity and permeability of caprock leakage pathways as CO2-acidified brine flows through them. Three models were developed. Firstly, a reactive transport model, Permeability Evolution of Leakage pathway (PEL), was developed to simulate permeability evolution of a leakage pathway during the injection period, and assumes calcite is the only reactive mineral. The system domain is a 100 m long by 0.2 m diameter cylindrical flow path with fixed boundaries containing a rock matrix with an initial porosity of 30% and initial permeability of 1×10-13 m2. One example result is for an initial calcite volume fraction (CVF) of 0.20, in which all the calcite is dissolved after 50 years and the permeability reaches 3.2×10-13 m2. For smaller values of CVF, the permeability reaches its final value earlier but the increase in permeability is minimal. For a large value of CVF such as 0.50, the permeability could eventually reach 1×10-12 m2, but the large amount of dissolved calcium buffers the solution and slows the reaction. After 50 years the permeability change is negligible. Thus, there is a non-monotonic relationship between the amount of calcite in the rock and the resulting permeability change because of the competing dynamics of calcite dissolution and alkalinity build-up. In the second model, PEL was coupled to an existing basin-scale multiphase flow model, Princeton's Estimating Leakage Semi-Analytical (ELSA) model. The new model, ELSA-PEL, estimates the brine and CO2 leakage rates during the injection period under conditions of permeability evolution. The scenario considered in this work is for 50 years of CO2 injection into the Mt. Simon formation in

  2. Directed evolution of a second xylitol catabolic pathway in Klebsiella pneumoniae.

    PubMed Central

    Doten, R C; Mortlock, R P

    1984-01-01

    Klebsiella pneumoniae PRL-R3 has inducible catabolic pathways for the degradation of ribitol and D-arabitol but cannot utilize xylitol as a growth substrate. A mutation in the rbtB regulatory gene of the ribitol operon permits the constitutive synthesis of the ribitol catabolic enzymes and allows growth on xylitol. The evolved xylitol catabolic pathway consists of an induced D-arabitol permease system that also transports xylitol, a constitutively synthesized ribitol dehydrogenase that oxidizes xylitol at the C-2 position to produce D-xylulose, and an induced D-xylulokinase from either the D-arabitol or D-xylose catabolic pathway. To investigate the potential of K. pneumoniae to evolve a different xylitol catabolic pathway, strains were constructed which were unable to synthesize ribitol dehydrogenase or either type of D-xylulokinase but constitutively synthesized the D-arabitol permease system. These strains had an inducible L-xylulokinase; therefore, the evolution of an enzyme which oxidized xylitol at the C-4 position to L-xylulose would establish a new xylitol catabolic pathway. Four independent xylitol-utilizing mutants were isolated, each of which had evolved a xylitol-4-dehydrogenase activity. The four dehydrogenases appeared to be identical because they comigrated during nondenaturing polyacrylamide gel electrophoresis. This novel xylitol dehydrogenase was constitutively synthesized, whereas L-xylulokinase remained inducible. Transductional analysis showed that the evolved dehydrogenase was not an altered ribitol or D-arabitol dehydrogenase and that the evolved dehydrogenase structural gene was not linked to the pentitol gene cluster. This evolved dehydrogenase had the highest activity with xylitol as a substrate, a Km for xylitol of 1.4 M, and a molecular weight of 43,000. Images PMID:6378891

  3. The evolution of the ribosome biogenesis pathway from a yeast perspective

    PubMed Central

    Ebersberger, Ingo; Simm, Stefan; Leisegang, Matthias S.; Schmitzberger, Peter; Mirus, Oliver; von Haeseler, Arndt; Bohnsack, Markus T.; Schleiff, Enrico

    2014-01-01

    Ribosome biogenesis is fundamental for cellular life, but surprisingly little is known about the underlying pathway. In eukaryotes a comprehensive collection of experimentally verified ribosome biogenesis factors (RBFs) exists only for Saccharomyces cerevisiae. Far less is known for other fungi, animals or plants, and insights are even more limited for archaea. Starting from 255 yeast RBFs, we integrated ortholog searches, domain architecture comparisons and, in part, manual curation to investigate the inventories of RBF candidates in 261 eukaryotes, 26 archaea and 57 bacteria. The resulting phylogenetic profiles reveal the evolutionary ancestry of the yeast pathway. The oldest core comprising 20 RBF lineages dates back to the last universal common ancestor, while the youngest 20 factors are confined to the Saccharomycotina. On this basis, we outline similarities and differences of ribosome biogenesis across contemporary species. Archaea, so far a rather uncharted domain, possess 38 well-supported RBF candidates of which some are known to form functional sub-complexes in yeast. This provides initial evidence that ribosome biogenesis in eukaryotes and archaea follows similar principles. Within eukaryotes, RBF repertoires vary considerably. A comparison of yeast and human reveals that lineage-specific adaptation via RBF exclusion and addition characterizes the evolution of this ancient pathway. PMID:24234440

  4. RAS/MAPK Activation Drives Resistance to Smo Inhibition, Metastasis, and Tumor Evolution in Shh Pathway-Dependent Tumors.

    PubMed

    Zhao, Xuesong; Ponomaryov, Tatyana; Ornell, Kimberly J; Zhou, Pengcheng; Dabral, Sukriti K; Pak, Ekaterina; Li, Wei; Atwood, Scott X; Whitson, Ramon J; Chang, Anne Lynn S; Li, Jiang; Oro, Anthony E; Chan, Jennifer A; Kelleher, Joseph F; Segal, Rosalind A

    2015-09-01

    Aberrant Shh signaling promotes tumor growth in diverse cancers. The importance of Shh signaling is particularly evident in medulloblastoma and basal cell carcinoma (BCC), where inhibitors targeting the Shh pathway component Smoothened (Smo) show great therapeutic promise. However, the emergence of drug resistance limits long-term efficacy, and the mechanisms of resistance remain poorly understood. Using new medulloblastoma models, we identify two distinct paradigms of resistance to Smo inhibition. Sufu mutations lead to maintenance of the Shh pathway in the presence of Smo inhibitors. Alternatively activation of the RAS-MAPK pathway circumvents Shh pathway dependency, drives tumor growth, and enhances metastatic behavior. Strikingly, in BCC patients treated with Smo inhibitor, squamous cell cancers with RAS/MAPK activation emerged from the antecedent BCC tumors. Together, these findings reveal a critical role of the RAS-MAPK pathway in drug resistance and tumor evolution of Shh pathway-dependent tumors.

  5. RAS/MAPK activation drives resistance to Smo inhibition, metastasis and tumor evolution in Shh pathway-dependent tumors

    PubMed Central

    Zhao, Xuesong; Ponomaryov, Tatyana; Ornell, Kimberly J.; Zhou, Pengcheng; Dabral, Sukriti K.; Pak, Ekaterina; Li, Wei; Atwood, Scott X.; Whitson, Ramon J.; Chang, Anne Lynn S.; Li, Jiang; Oro, Anthony E.; Chan, Jennifer A.; Kelleher, Joseph F.; Segal, Rosalind A.

    2015-01-01

    Aberrant Shh signaling promotes tumor growth in diverse cancers. The importance of Shh signaling is particularly evident in medulloblastoma and basal cell carcinoma (BCC), where inhibitors targeting the Shh pathway component Smoothened (Smo) show great therapeutic promise. However, the emergence of drug resistance limits long-term efficacy and the mechanisms of resistance remain poorly understood. Using new medulloblastoma models, we identify two distinct paradigms of resistance to Smo inhibition. Sufu mutations lead to maintenance of the Shh pathway in the presence of Smo inhibitors. Alternatively activation of the RAS/MAPK pathway circumvents Shh pathway-dependency, drives tumor growth and enhances metastatic behavior. Strikingly, in BCC patients treated with Smo inhibitor, squamous cell cancers with RAS/MAPK activation emerged from the antecedent BCC tumors. Together these findings reveal a critical role of RAS/MAPK pathway in drug resistance and tumor evolution of Shh pathway-dependent tumors. PMID:26130651

  6. Color vision of the coelacanth (Latimeria chalumnae) and adaptive evolution of rhodopsin (RH1) and rhodopsin-like (RH2) pigments.

    PubMed

    Yokoyama, S

    2000-01-01

    The coelacanth, a "living fossil," lives at a depth of about 200 m near the coast of the Comoros archipelago in the Indian Ocean and receives only a narrow range of light at about 480 nm. To see the entire range of "color" the Comoran coelacanth appears to use only rod-specific RH1 and cone-specific RH2 visual pigments, with the optimum light sensitivities (lambda max) at 478 nm and 485 nm, respectively. These blue-shifted lambda max values of RH1 and RH2 pigments are fully explained by independent double amino acid replacements E122Q/A292S and E122Q/M207L, respectively. More generally, currently available mutagenesis experiments identify only 10 amino acid changes that shift the lambda max values of visual pigments more than 5 nm. Among these, D83N, E1220, M207L, and A292S are associated strongly with the adaptive blue shifts in the lambda max values of RH1 and RH2 pigments in vertebrates.

  7. Comparative genomic analysis of nine Sphingobium strains: Insights into their evolution and hexachlorocyclohexane (HCH) degradation pathways

    DOE PAGES

    Verma, Helianthous; Kumar, Roshan; Oldach, Phoebe; ...

    2014-11-23

    Background: Sphingobium spp. are efficient degraders of a wide range of chlorinated and aromatic hydrocarbons. In particular, strains which harbour the lin pathway genes mediating the degradation of hexachlorocyclohexane (HCH) isomers are of interest due to the widespread persistence of this contaminant. Here, we examined the evolution and diversification of the lin pathway under the selective pressure of HCH, by comparing the draft genomes of six newly-sequenced Sphingobium spp. (strains LL03, DS20, IP26, HDIPO4, P25 and RL3) isolated from HCH dumpsites, with three existing genomes (S. indicum B90A, S. japonicum UT26S and Sphingobium sp. SYK6). Results: Efficient HCH degraders phylogeneticallymore » clustered in a closely related group comprising of UT26S, B90A, HDIPO4 and IP26, where HDIPO4 and IP26 were classified as subspecies with ANI value >98%. Less than 10% of the total gene content was shared among all nine strains, but among the eight HCH-associated strains, that is all except SYK6, the shared gene content jumped to nearly 25%. Genes associated with nitrogen stress response and two-component systems were found to be enriched. The strains also housed many xenobiotic degradation pathways other than HCH, despite the absence of these xenobiotics from isolation sources. In addition, these strains, although non-motile, but posses flagellar assembly genes. While strains HDIPO4 and IP26 contained the complete set of lin genes, DS20 was entirely devoid of lin genes (except linKLMN) whereas, LL03, P25 and RL3 were identified as lin deficient strains, as they housed incomplete lin pathways. Further, in HDIPO4, linA was found as a hybrid of two natural variants i.e., linA1 and linA2 known for their different enantioselectivity. In conclusion, the bacteria isolated from HCH dumpsites provide a natural testing ground to study variations in the lin system and their effects on degradation efficacy. Further, the diversity in the lin gene sequences and copy number, their

  8. Optimization and evolution in metabolic pathways: global optimization techniques in Generalized Mass Action models.

    PubMed

    Sorribas, Albert; Pozo, Carlos; Vilaprinyo, Ester; Guillén-Gosálbez, Gonzalo; Jiménez, Laureano; Alves, Rui

    2010-09-01

    Cells are natural factories that can adapt to changes in external conditions. Their adaptive responses to specific stress situations are a result of evolution. In theory, many alternative sets of coordinated changes in the activity of the enzymes of each pathway could allow for an appropriate adaptive readjustment of metabolism in response to stress. However, experimental and theoretical observations show that actual responses to specific changes follow fairly well defined patterns that suggest an evolutionary optimization of that response. Thus, it is important to identify functional effectiveness criteria that may explain why certain patterns of change in cellular components and activities during adaptive response have been preferably maintained over evolutionary time. Those functional effectiveness criteria define sets of physiological requirements that constrain the possible adaptive changes and lead to different operation principles that could explain the observed response. Understanding such operation principles can also facilitate biotechnological and metabolic engineering applications. Thus, developing methods that enable the analysis of cellular responses from the perspective of identifying operation principles may have strong theoretical and practical implications. In this paper we present one such method that was designed based on nonlinear global optimization techniques. Our methodology can be used with a special class of nonlinear kinetic models known as GMA models and it allows for a systematic characterization of the physiological requirements that may underlie the evolution of adaptive strategies.

  9. Parallel evolution of Nitric Oxide signaling: Diversity of synthesis & memory pathways

    PubMed Central

    Moroz, Leonid L.; Kohn, Andrea B.

    2014-01-01

    The origin of NO signaling can be traceable back to the origin of life with the large scale of parallel evolution of NO synthases (NOSs). Inducible-like NOSs may be the most basal prototype of all NOSs and that neuronal-like NOS might have evolved several times from this prototype. Other enzymatic and non-enzymatic pathways for NO synthesis have been discovered using reduction of nitrites, an alternative source of NO. Diverse synthetic mechanisms can co-exist within the same cell providing a complex NO-oxygen microenvironment tightly coupled with cellular energetics. The dissection of multiple sources of NO formation is crucial in analysis of complex biological processes such as neuronal integration and learning mechanisms when NO can act as a volume transmitter within memory-forming circuits. In particular, the molecular analysis of learning mechanisms (most notably in insects and gastropod molluscs) opens conceptually different perspectives to understand the logic of recruiting evolutionarily conserved pathways for novel functions. Giant uniquely identified cells from Aplysia and related species precent unuque opportunities for integrative analysis of NO signaling at the single cell level. PMID:21622160

  10. Evolution of mitochondrial cell death pathway: Proapoptotic role of HtrA2/Omi in Drosophila

    SciTech Connect

    Igaki, Tatsushi; Suzuki, Yasuyuki; Tokushige, Naoko; Aonuma, Hiroka; Takahashi, Ryosuke . E-mail: ryosuket@kuhp.kyoto-u.ac.jp; Miura, Masayuki . E-mail: miura@mol.f.u-tokyo.ac.jp

    2007-05-18

    Despite the essential role of mitochondria in a variety of mammalian cell death processes, the involvement of mitochondrial pathway in Drosophila cell death has remained unclear. To address this, we cloned and characterized DmHtrA2, a Drosophila homolog of a mitochondrial serine protease HtrA2/Omi. We show that DmHtrA2 normally resides in mitochondria and is up-regulated by UV-irradiation. Upon receipt of apoptotic stimuli, DmHtrA2 is translocated to extramitochondrial compartment; however, unlike its mammalian counterpart, the extramitochondrial DmHtrA2 does not diffuse throughout the cytosol but stays near the mitochondria. RNAi-mediated knock-down of DmHtrA2 in larvae or adult flies results in a resistance to stress stimuli. DmHtrA2 specifically cleaves Drosophila inhibitor-of-apoptosis protein 1 (DIAP1), a cellular caspase inhibitor, and induces cell death both in vitro and in vivo as potent as other fly cell death proteins. Our observations suggest that DmHtrA2 promotes cell death through a cleavage of DIAP1 in the vicinity of mitochondria, which may represent a prototype of mitochondrial cell death pathway in evolution.

  11. 3,3'-Diindolylmethane inhibits VEGF expression through the HIF-1α and NF-κB pathways in human retinal pigment epithelial cells under chemical hypoxic conditions.

    PubMed

    Park, Hongzoo; Lee, Dae-Sung; Yim, Mi-Jin; Choi, Yung Hyun; Park, Saegwang; Seo, Su-Kil; Choi, Jung Sik; Jang, Won Hee; Yea, Sung Su; Park, Won Sun; Lee, Chang-Min; Jung, Won-Kyo; Choi, Il-Whan

    2015-07-01

    Oxidative stress in the retinal pigment epithelium (RPE) can lead to the pathological causes of age-related macular degeneration (AMD). Hypoxia induces oxidative damage in retinal pigment epithelial cells (RPE cells). In this study, we investigated the capacity of 3,3'-diindolylmethane (DIM) to reduce the expression of vascular endothelial growth factor (VEGF) under hypoxic conditions, as well as the molecular mechanisms involved. Human RPE cells (ARPE-19 cells) were treated with cobalt chloride (CoCl2, 200 µM) and/or DIM (10 and 20 µM). The production of VEGF was measured by enzyme-linked immunosorbent assay. The translocation of hypoxia-inducible factor-1α (HIF-1α) and nuclear factor-κB (NF-κB) was determined by western blot analysis. The binding activity of HIF-1α and NF-κB was analyzed by electrophoretic mobility shift assay. The phosphorylation levels of mitogen-activated protein kinases (MAPKs) were measured by western blot analysis. The levels of mitochondrial reactive oxygen species (ROS) were detected by fluorescence microplate assay. The results revealed that DIM significantly attenuated the CoCl2-induced expression of VEGF in the ARPE-19 cells. The CoCl2-induced translocation and activation of HIF-1α and NF-κB were also attenuated by treatment with DIM. In addition, DIM inhibited the CoCl2-induced activation of p38 MAPK in the ARPE-19 cells. Pre-treatment with YCG063, a mitochondrial ROS inhibitor, led to the downregulation of the CoCl2-induced production of VEGF by suppressing HIF-1α and NF-κB activity. Taken together, the findings of our study demonstrate that DIM inhibits the CoCl2-induced production of VEGF by suppressing mitochondrial ROS production, thus attenuating the activation of HIF-1α and p38 MAPK/NF-κB.

  12. Oral pigmentation: A review.

    PubMed

    Sreeja, C; Ramakrishnan, K; Vijayalakshmi, D; Devi, M; Aesha, I; Vijayabanu, B

    2015-08-01

    Pigmentations are commonly found in the mouth. They represent in various clinical patterns that can range from just physiologic changes to oral manifestations of systemic diseases and malignancies. Color changes in the oral mucosa can be attributed to the deposition of either endogenous or exogenous pigments as a result of various mucosal diseases. The various pigmentations can be in the form of blue/purple vascular lesions, brown melanotic lesions, brown heme-associated lesions, gray/black pigmentations.

  13. Oral pigmentation: A review

    PubMed Central

    Sreeja, C.; Ramakrishnan, K.; Vijayalakshmi, D.; Devi, M.; Aesha, I.; Vijayabanu, B.

    2015-01-01

    Pigmentations are commonly found in the mouth. They represent in various clinical patterns that can range from just physiologic changes to oral manifestations of systemic diseases and malignancies. Color changes in the oral mucosa can be attributed to the deposition of either endogenous or exogenous pigments as a result of various mucosal diseases. The various pigmentations can be in the form of blue/purple vascular lesions, brown melanotic lesions, brown heme-associated lesions, gray/black pigmentations. PMID:26538887

  14. Overview of plant pigments

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Chlorophylls, carotenoids, flavonoids and betalains are four major classes of biological pigments produced in plants. Chlorophylls are the primary pigments responsible for plant green and photosynthesis. The other three are accessary pigments and secondary metabolites that yield non-green colors and...

  15. Competition between anthocyanin and flavonol biosynthesis produces spatial pattern variation of floral pigments between Mimulus species.

    PubMed

    Yuan, Yao-Wu; Rebocho, Alexandra B; Sagawa, Janelle M; Stanley, Lauren E; Bradshaw, Harvey D

    2016-03-01

    Flower color patterns have long served as a model for developmental genetics because pigment phenotypes are visually striking, yet generally not required for plant viability, facilitating the genetic analysis of color and pattern mutants. The evolution of novel flower colors and patterns has played a key role in the adaptive radiation of flowering plants via their specialized interactions with different pollinator guilds (e.g., bees, butterflies, birds), motivating the search for allelic differences affecting flower color pattern in closely related plant species with different pollinators. We have identified LIGHT AREAS1 (LAR1), encoding an R2R3-MYB transcription factor, as the causal gene underlying the spatial pattern variation of floral anthocyanin pigmentation between two sister species of monkeyflower: the bumblebee-pollinated Mimulus lewisii and the hummingbird-pollinated Mimulus cardinalis. We demonstrated that LAR1 positively regulates FLAVONOL SYNTHASE (FLS), essentially eliminating anthocyanin biosynthesis in the white region (i.e., light areas) around the corolla throat of M. lewisii flowers by diverting dihydroflavonol into flavonol biosynthesis from the anthocyanin pigment pathway. FLS is preferentially expressed in the light areas of the M. lewisii flower, thus prepatterning the corolla. LAR1 expression in M. cardinalis flowers is much lower than in M. lewisii, explaining the unpatterned phenotype and recessive inheritance of the M. cardinalis allele. Furthermore, our gene-expression analysis and genetic mapping results suggest that cis-regulatory change at the LAR1 gene played a critical role in the evolution of different pigmentation patterns between the two species.

  16. Nested modeling approach to quantify sediment transport pathways and temporal variability of barrier island evolution

    NASA Astrophysics Data System (ADS)

    Long, J. W.; Dalyander, S.; Sherwood, C. R.; Thompson, D. M.; Plant, N. G.

    2012-12-01

    The Chandeleur Islands, situated off the coast of Louisiana in the Gulf of Mexico, comprise a sand-starved barrier island system that has been disintegrating over the last decade. The persistent sediment transport in this area is predominantly directed alongshore but overwash and inundation during storm conditions has fragmented the island and reduced the subaerial extent by almost 75% since 2001. From 2010-2011 a sand berm was constructed along the Gulf side of the island adding 20 million cubic yards of sediment to this barrier island system. The redistribution of this sediment, particularly whether it remains in the active system and progrades the barrier island, has been evaluated using a series of numerical models and an extensive set of in situ and remote sensing observations. We have developed a coupled numerical modeling system capable of simulating morphologic evolution of the sand berm and barrier island using observations and predictions of regional and nearshore oceanographic processes. A nested approach provides large scale oceanographic information to force island evolution in a series of smaller grids, including two nearshore domains that are designed to simulate (1) the persistent alongshore sediment transport O(months-years) and (2) the overwash and breaching of the island/berm due to cross-shore forcing driven by winter cold fronts and tropical storms (O(hours-days)). The coupled model is evaluated using the observations of waves, water levels, currents, and topographic/morphologic change. Modeled processes are then used to identify the dominant sediment transport pathways and quantify the role of alongshore and cross-shore sediment transport in evolving the barrier island over a range of temporal scales.

  17. Benzoxazinoid biosynthesis, a model for evolution of secondary metabolic pathways in plants.

    PubMed

    Frey, Monika; Schullehner, Katrin; Dick, Regina; Fiesselmann, Andreas; Gierl, Alfons

    2009-01-01

    Benzoxazinoids are secondary metabolites that are effective in defence and allelopathy. They are synthesised in two subfamilies of the Poaceae and sporadically found in single species of the dicots. The biosynthesis is fully elucidated in maize; here the genes encoding the enzymes of the pathway are in physical proximity. This "biosynthetic cluster" might facilitate coordinated gene regulation. Data from Zea mays, Triticum aestivum and Hordeum lechleri suggest that the pathway is of monophyletic origin in the Poaceae. The branchpoint from the primary metabolism (Bx1 gene) can be traced back to duplication and functionalisation of the alpha-subunit of tryptophan synthase (TSA). Modification of the intermediates by consecutive hydroxylation is catalysed by members of a cytochrome P450 enzyme subfamily (Bx2-Bx5). Glucosylation by an UDP-glucosyltransferase (UGT, Bx8, Bx9) is essential for the reduction of autotoxicity of the benzoxazinoids. In some species 2,4-dihydroxy-1,4-benzoxazin-3-one-glucoside (DIBOA-glc) is further modified by the 2-oxoglutarate-dependent dioxygenase BX6 and the O-methyltransferase BX7. In the dicots Aphelandra squarrosa, Consolida orientalis, and Lamium galeobdolon, benzoxazinoid biosynthesis is analogously organised: The branchpoint is established by a homolog of TSA, P450 enzymes catalyse hydroxylations and at least the first hydroxylation reaction is identical in dicots and Poaceae, the toxic aglucon is glucosylated by an UGT. Functionally, TSA and BX1 are indole-glycerolphosphate lyases (IGLs). Igl genes seem to be generally duplicated in angiosperms. Modelling and biochemical characterisation of IGLs reveal that the catalytic properties of the enzyme can easily be modified by mutation. Independent evolution can be assumed for the BX1 function in dicots and Poaceae.

  18. Structural and functional evolution of isopropylmalate dehydrogenases in the leucine and glucosinolate pathways of Arabidopsis thaliana

    SciTech Connect

    He, Yan; Galant, Ashley; Pang, Qiuying; Strul, Johanna M.; Balogun, Sherifat F.; Jez, Joseph M.; Chen, Sixue

    2012-10-24

    The methionine chain-elongation pathway is required for aliphatic glucosinolate biosynthesis in plants and evolved from leucine biosynthesis. In Arabidopsis thaliana, three 3-isopropylmalate dehydrogenases (AtIPMDHs) play key roles in methionine chain-elongation for the synthesis of aliphatic glucosinolates (e.g. AtIPMDH1) and leucine (e.g. AtIPMDH2 and AtIPMDH3). Here we elucidate the molecular basis underlying the metabolic specialization of these enzymes. The 2.25 {angstrom} resolution crystal structure of AtIPMDH2 was solved to provide the first detailed molecular architecture of a plant IPMDH. Modeling of 3-isopropylmalate binding in the AtIPMDH2 active site and sequence comparisons of prokaryotic and eukaryotic IPMDH suggest that substitution of one active site residue may lead to altered substrate specificity and metabolic function. Site-directed mutagenesis of Phe-137 to a leucine in AtIPMDH1 (AtIPMDH1-F137L) reduced activity toward 3-(2'-methylthio)ethylmalate by 200-fold, but enhanced catalytic efficiency with 3-isopropylmalate to levels observed with AtIPMDH2 and AtIPMDH3. Conversely, the AtIPMDH2-L134F and AtIPMDH3-L133F mutants enhanced catalytic efficiency with 3-(2'-methylthio)ethylmalate {approx}100-fold and reduced activity for 3-isopropylmalate. Furthermore, the altered in vivo glucosinolate profile of an Arabidopsis ipmdh1 T-DNA knock-out mutant could be restored to wild-type levels by constructs expressing AtIPMDH1, AtIPMDH2-L134F, or AtIPMDH3-L133F, but not by AtIPMDH1-F137L. These results indicate that a single amino acid substitution results in functional divergence of IPMDH in planta to affect substrate specificity and contributes to the evolution of specialized glucosinolate biosynthesis from the ancestral leucine pathway.

  19. Alternate pathways of body shape evolution translate into common patterns of locomotor evolution in two clades of lizards.

    PubMed

    Bergmann, Philip J; Irschick, Duncan J

    2010-06-01

    Body shape has a fundamental impact on organismal function, but it is unknown how functional morphology and locomotor performance and kinematics relate across a diverse array of body shapes. We showed that although patterns of body shape evolution differed considerably between lizards of the Phrynosomatinae and Lerista, patterns of locomotor evolution coincided between clades. Specifically, we found that the phrynosomatines evolved a stocky phenotype through body widening and limb shortening, whereas Lerista evolved elongation through body lengthening and limb shortening. In both clades, relative limb length played a key role in locomotor evolution and kinematic strategies, with long-limbed species moving faster and taking longer strides. In Lerista, the body axis also influenced locomotor evolution. Similar patterns of locomotor evolution were likely due to constraints on how the body can move. However, these common patterns of locomotor evolution between the two clades resulted in different kinematic strategies and levels of performance among species because of their morphological differences. Furthermore, we found no evidence that distinct body shapes are adaptations to different substrates, as locomotor kinematics did not change on loose or solid substrates. Our findings illustrate the importance of studying kinematics to understand the mechanisms of locomotor evolution and phenotype-function relationships.

  20. Reversal of the Caspase-Dependent Apoptotic Cytotoxicity Pathway by Taurine from Lycium barbarum (Goji Berry) in Human Retinal Pigment Epithelial Cells: Potential Benefit in Diabetic Retinopathy.

    PubMed

    Song, M K; Roufogalis, B D; Huang, T H W

    2012-01-01

    Diabetic retinopathy is a preventable microvascular diabetic complication and a leading cause of vision loss. Retinal pigment epithelial cell apoptosis is an early event in diabetic retinopathy. Taurine is reportedly beneficial for diabetic retinopathy and is abundant in the fruit of Lycium barbarum (LB). We have investigated the effect of pure taurine and an extract of LB rich in taurine on a model of diabetic retinopathy, the retinal ARPE-19 cell line exposed to high glucose. We demonstrate for the first time that LB extract and the active ligand, taurine, dose dependently enhance cell viability following high glucose treatment in the ARPE-19 retinal epithelial cell line. This cytoprotective effect was associated with the attenuation of high glucose-induced apoptosis, which was shown by characteristic morphological staining and the dose-dependent decrease in the number of apoptotic cells, determined by flow cytometry. Moreover, we have shown that LB extract and taurine dose dependently downregulate caspase-3 protein expression and the enzymatic activity of caspase-3. We conclude that taurine, a major component of LB, and the LB extract, have a cytoprotective effect against glucose exposure in a human retinal epithelial cell line and may provide useful approaches to delaying diabetic retinopathy progression.

  1. Reversal of the Caspase-Dependent Apoptotic Cytotoxicity Pathway by Taurine from Lycium barbarum (Goji Berry) in Human Retinal Pigment Epithelial Cells: Potential Benefit in Diabetic Retinopathy

    PubMed Central

    Song, M. K.; Roufogalis, B. D.; Huang, T. H. W.

    2012-01-01

    Diabetic retinopathy is a preventable microvascular diabetic complication and a leading cause of vision loss. Retinal pigment epithelial cell apoptosis is an early event in diabetic retinopathy. Taurine is reportedly beneficial for diabetic retinopathy and is abundant in the fruit of Lycium barbarum (LB). We have investigated the effect of pure taurine and an extract of LB rich in taurine on a model of diabetic retinopathy, the retinal ARPE-19 cell line exposed to high glucose. We demonstrate for the first time that LB extract and the active ligand, taurine, dose dependently enhance cell viability following high glucose treatment in the ARPE-19 retinal epithelial cell line. This cytoprotective effect was associated with the attenuation of high glucose-induced apoptosis, which was shown by characteristic morphological staining and the dose-dependent decrease in the number of apoptotic cells, determined by flow cytometry. Moreover, we have shown that LB extract and taurine dose dependently downregulate caspase-3 protein expression and the enzymatic activity of caspase-3. We conclude that taurine, a major component of LB, and the LB extract, have a cytoprotective effect against glucose exposure in a human retinal epithelial cell line and may provide useful approaches to delaying diabetic retinopathy progression. PMID:22567031

  2. Genetics of pigmentation and melanoma predisposition.

    PubMed

    Pho, L N; Leachman, S A

    2010-02-01

    About 5-10% of human cutaneous malignant melanoma is hereditary and known to involve rare germline mutations in highly penetrant, autosomal dominant genes. These genes are important in cell cycle control but are not responsible for all familial cases of melanoma. Epidemiologic studies have linked specific phenotypic traits including fair skin, light-colored eyes, and poor tanning ability to melanoma risks. The ability to visually discern and define pigmentary phenotypes in humans and in animal models has permitted elucidation of many genes involved in pigmentation and melanin biosynthesis. Additional genetic epidemiological studies have recently identified a subset of these pigmentation genes that are associated with risk for melanoma and other cutaneous malignancies as well as photosensitivity. Genome-wide association studies (GWAS) have unveiled single nucleotide polymorphisms (SNPs) or genetic variants in MC1R, TPCN2, ASIP, KITLG, NCKX5, TYR, IRF4, OCA2, and TYRP1 pigmentation genes. These findings emphasize the contribution of pigmentation pathways to melanoma predisposition and tumorigenesis through gene-environment interactions. Since pigmentation genes in the melanin synthesis pathway also confer risk for cutaneous malignancy, a better understanding of the operative molecular mechanisms involved in this relationship has the potential to impact individual risk assessment for cutaneous malignant melanoma in the future. This paper is an overview of our current understanding of pigmentation gene modifications that have been associated with melanoma risk and how these genes can enrich clinical management, prevention, and early detection of malignant melanoma.

  3. Convergent evolution of the arginine deiminase pathway: the ArcD and ArcE arginine/ornithine exchangers.

    PubMed

    Noens, Elke E E; Lolkema, Juke S

    2017-02-01

    The arginine deiminase (ADI) pathway converts L-arginine into L-ornithine and yields 1 mol of ATP per mol of L-arginine consumed. The L-arginine/L-ornithine exchanger in the pathway takes up L-arginine and excretes L-ornithine from the cytoplasm. Analysis of the genomes of 1281 bacterial species revealed the presence of 124 arc gene clusters encoding the pathway. About half of the clusters contained the gene encoding the well-studied L-arginine/L-ornithine exchanger ArcD, while the other half contained a gene, termed here arcE, encoding a membrane protein that is not a homolog of ArcD. The arcE gene product of Streptococcus pneumoniae was shown to take up L-arginine and L-ornithine with affinities of 0.6 and 1 μmol/L, respectively, and to catalyze metabolic energy-independent, electroneutral exchange. ArcE of S. pneumoniae could replace ArcD in the ADI pathway of Lactococcus lactis and provided the cells with a growth advantage. In contrast to ArcD, ArcE catalyzed translocation of the pathway intermediate L-citrulline with high efficiency. A short version of the ADI pathway is proposed for L-citrulline catabolism and the presence of the evolutionary unrelated arcD and arcE genes in different organisms is discussed in the context of the evolution of the ADI pathway.

  4. Molecular evolution of NASP and conserved histone H3/H4 transport pathway

    PubMed Central

    2014-01-01

    Background NASP is an essential protein in mammals that functions in histone transport pathways and maintenance of a soluble reservoir of histones H3/H4. NASP has been studied exclusively in Opisthokonta lineages where some functional diversity has been reported. In humans, growing evidence implicates NASP miss-regulation in the development of a variety of cancers. Although a comprehensive phylogenetic analysis is lacking, NASP-family proteins that possess four TPR motifs are thought to be widely distributed across eukaryotes. Results We characterize the molecular evolution of NASP by systematically identifying putative NASP orthologs across diverse eukaryotic lineages ranging from excavata to those of the crown group. We detect extensive silent divergence at the nucleotide level suggesting the presence of strong purifying selection acting at the protein level. We also observe a selection bias for high frequencies of acidic residues which we hypothesize is a consequence of their critical function(s), further indicating the role of functional constraints operating on NASP evolution. Our data indicate that TPR1 and TPR4 constitute the most rapidly evolving functional units of NASP and may account for the functional diversity observed among well characterized family members. We also show that NASP paralogs in ray-finned fish have different genomic environments with clear differences in their GC content and have undergone significant changes at the protein level suggesting functional diversification. Conclusion We draw four main conclusions from this study. First, wide distribution of NASP throughout eukaryotes suggests that it was likely present in the last eukaryotic common ancestor (LECA) possibly as an important innovation in the transport of H3/H4. Second, strong purifying selection operating at the protein level has influenced the nucleotide composition of NASP genes. Further, we show that selection has acted to maintain a high frequency of functionally relevant

  5. Genetic basis of eye and pigment loss in the cave crustacean, Asellus aquaticus.

    PubMed

    Protas, Meredith E; Trontelj, Peter; Patel, Nipam H

    2011-04-05

    Understanding the process of evolution is one of the great challenges in biology. Cave animals are one group with immense potential to address the mechanisms of evolutionary change. Amazingly, similar morphological alterations, such as enhancement of sensory systems and the loss of eyes and pigmentation, have evolved multiple times in a diverse assemblage of cave animals. Our goal is to develop an invertebrate model to study cave evolution so that, in combination with a previously established vertebrate cave system, we can address genetic questions concerning evolutionary parallelism and convergence. We chose the isopod crustacean, Asellus aquaticus, and generated a genome-wide linkage map for this species. Our map, composed of 117 markers, of which the majority are associated with genes known to be involved in pigmentation, eye, and appendage development, was used to identify loci of large effect responsible for several pigmentation traits and eye loss. Our study provides support for the prediction that significant morphological change can be mediated through one or a few genes. Surprisingly, we found that within population variability in eye size occurs through multiple mechanisms; eye loss has a different genetic basis than reduced eye size. Similarly, again within a population, the phenotype of albinism can be achieved by two different genetic pathways--either by a recessive genotype at one locus or doubly recessive genotypes at two other loci. Our work shows the potential of Asellus for studying the extremes of parallel and convergent evolution-spanning comparisons within populations to comparisons between vertebrate and arthropod systems.

  6. Evolution of sexes from an ancestral mating-type specification pathway.

    PubMed

    Geng, Sa; De Hoff, Peter; Umen, James G

    2014-07-01

    Male and female sexes have evolved repeatedly in eukaryotes but the origins of dimorphic sexes and their relationship to mating types in unicellular species are not understood. Volvocine algae include isogamous species such as Chlamydomonas reinhardtii, with two equal-sized mating types, and oogamous multicellular species such as Volvox carteri with sperm-producing males and egg-producing females. Theoretical work predicts genetic linkage of a gamete cell-size regulatory gene(s) to an ancestral mating-type locus as a possible step in the evolution of dimorphic gametes, but this idea has not been tested. Here we show that, contrary to predictions, a single conserved mating locus (MT) gene in volvocine algae-MID, which encodes a RWP-RK domain transcription factor-evolved from its ancestral role in C. reinhardtii as a mating-type specifier, to become a determinant of sperm and egg development in V. carteri. Transgenic female V. carteri expressing male MID produced functional sperm packets during sexual development. Transgenic male V. carteri with RNA interference (RNAi)-mediated knockdowns of VcMID produced functional eggs, or self-fertile hermaphrodites. Post-transcriptional controls were found to regulate cell-type-limited expression and nuclear localization of VcMid protein that restricted its activity to nuclei of developing male germ cells and sperm. Crosses with sex-reversed strains uncoupled sex determination from sex chromosome identity and revealed gender-specific roles for male and female mating locus genes in sexual development, gamete fitness and reproductive success. Our data show genetic continuity between the mating-type specification and sex determination pathways of volvocine algae, and reveal evidence for gender-specific adaptations in the male and female mating locus haplotypes of Volvox. These findings will enable a deeper understanding of how a master regulator of mating-type determination in an ancestral unicellular species was reprogrammed to

  7. The evolution of alternative biofilms in an opportunistic fungal pathogen: an explanation for how new signal transduction pathways may evolve.

    PubMed

    Soll, David R

    2014-03-01

    The evolution of two types of biofilms, one pathogenic and one sexual, is unique for Candidaalbicans, the most pervasive fungal pathogen in humans. When in the predominant a/α configuration, cells can form a traditional biofilm made up of a basal layer of yeast cells and an extensive upper layer of hyphae and dense matrix. This a/α biofilm is impermeable, impenetrable and drug-resistant. When in the a/a or α/α configuration, white cells form a biofilm of similar architecture, but which is permeable, penetrable and drug-susceptible. The latter biofilm facilitates mating between minority opaque a/a and α/α cells. The two biofilms are regulated by different signal transduction pathways that provide clues for deducing not only how the sexual a/a or α/α biofilms evolved, but how the pathogenic a/α biofilm evolved as well. In the deduced evolutionary models, regulatory molecules, including components of the signal transduction pathways and transcription factors, are recruited from conserved pathways. The evolution of the alternative biofilms of C. albicans provides a rare glimpse into how new regulatory pathways may evolve in general.

  8. Evolution and development of brain sensory organs in molgulid ascidians.

    PubMed

    Jeffery, William R

    2004-01-01

    The ascidian tadpole larva has two brain sensory organs containing melanocytes: the otolith, a gravity receptor, and the ocellus, part of a photoreceptor. One or both of these sensory organs are absent in molgulid ascidians. We show here that developmental changes leading to the loss of sensory pigment cells occur by different mechanisms in closely related molgulid species. Sensory pigment cells are formed through a bilateral determination pathway in which two or more precursor cells are specified as an equivalence group on each side of the embryo. The precursor cells subsequently converge at the midline after neurulation and undergo cell interactions that decide the fates of the otolith and ocellus. Molgula occidentalis and M. oculata, which exhibit a tadpole larva with an otolith but lacking an ocellus, have conserved the bilateral pigment cell determination pathway. Programmed cell death (PCD) is superimposed on this pathway late in development to eliminate the ocellus precursor and supernumerary pigment cells, which do not differentiate into either an otolith or ocellus. In contrast to molgulids with tadpole larvae, no pigment cell precursors are specified on either side of the M. occulta embryo, which forms a tailless (anural) larva lacking both sensory organs, suggesting that the bilateral pigment cell determination pathway has been lost. The bilateral pigment cell determination pathway and superimposed PCD can be restored in hybrids obtained by fertilizing M. occulta eggs with M. oculata sperm, indicating control by a zygotic process. We conclude that PCD plays an important role in the evolution and development of brain sensory organs in molgulid ascidians.

  9. Evolution of the TGF-β signaling pathway and its potential role in the ctenophore, Mnemiopsis leidyi.

    PubMed

    Pang, Kevin; Ryan, Joseph F; Baxevanis, Andreas D; Martindale, Mark Q

    2011-01-01

    The TGF-β signaling pathway is a metazoan-specific intercellular signaling pathway known to be important in many developmental and cellular processes in a wide variety of animals. We investigated the complexity and possible functions of this pathway in a member of one of the earliest branching metazoan phyla, the ctenophore Mnemiopsis leidyi. A search of the recently sequenced Mnemiopsis genome revealed an inventory of genes encoding ligands and the rest of the components of the TGF-β superfamily signaling pathway. The Mnemiopsis genome contains nine TGF-β ligands, two TGF-β-like family members, two BMP-like family members, and five gene products that were unable to be classified with certainty. We also identified four TGF-β receptors: three Type I and a single Type II receptor. There are five genes encoding Smad proteins (Smad2, Smad4, Smad6, and two Smad1s). While we have identified many of the other components of this pathway, including Tolloid, SMURF, and Nomo, notably absent are SARA and all of the known antagonists belonging to the Chordin, Follistatin, Noggin, and CAN families. This pathway likely evolved early in metazoan evolution as nearly all components of this pathway have yet to be identified in any non-metazoan. The complement of TGF-β signaling pathway components of ctenophores is more similar to that of the sponge, Amphimedon, than to cnidarians, Trichoplax, or bilaterians. The mRNA expression patterns of key genes revealed by in situ hybridization suggests that TGF-β signaling is not involved in ctenophore early axis specification. Four ligands are expressed during gastrulation in ectodermal micromeres along all three body axes, suggesting a role in transducing earlier maternal signals. Later expression patterns and experiments with the TGF-β inhibitor SB432542 suggest roles in pharyngeal morphogenesis and comb row organization.

  10. Cone visual pigments of monotremes: filling the phylogenetic gap.

    PubMed

    Wakefield, Matthew J; Anderson, Mark; Chang, Ellen; Wei, Ke-Jun; Kaul, Rajinder; Graves, Jennifer A Marshall; Grützner, Frank; Deeb, Samir S

    2008-01-01

    We have determined the sequence and genomic organization of the genes encoding the cone visual pigment of the platypus (Ornithorhynchus anatinus) and the echidna (Tachyglossus aculeatus), and inferred their spectral properties and evolutionary pathways. We prepared platypus and echidna retinal RNA and used primers of the middle-wave-sensitive (MWS), long-wave-sensitive (LWS), and short-wave sensitive (SWS1) pigments corresponding to coding sequences that are highly conserved among mammals; to PCR amplify the corresponding pigment sequences. Amplification from the retinal RNA revealed the expression of LWS pigment mRNA that is homologous in sequence and spectral properties to the primate LWS visual pigments. However, we were unable to amplify the mammalian SWS1 pigment from these two species, indicating this gene was lost prior to the echidna-platypus divergence (21 MYA). Subsequently, when the platypus genome sequence became available, we found an LWS pigment gene in a conserved genomic arrangement that resembles the primate pigment, but, surprisingly we found an adjacent (20 kb) SWS2 pigment gene within this conserved genomic arrangement. We obtained the same result after sequencing the echidna genes. The encoded SWS2 pigment is predicted to have a wavelength of maximal absorption of about 440 nm, and is paralogous to SWS pigments typically found in reptiles, birds, and fish but not in mammals. This study suggests the locus control region (LCR) has played an important role in the conservation of photo receptor gene arrays and the control of their spatial and temporal expression in the retina in all mammals. In conclusion, a duplication event of an ancestral cone visual pigment gene, followed by sequence divergence and selection gave rise to the LWS and SWS2 visual pigments. So far, the echidna and platypus are the only mammals that share the gene structure of the LWS-SWS2 pigment gene complex with reptiles, birds and fishes.

  11. Investigating the evolution of Shared Socioeconomic Pathways with a large number of scenarios

    NASA Astrophysics Data System (ADS)

    Schweizer, V. J.; Guivarch, C.; Rozenberg, J.

    2013-12-01

    The new scenario framework for climate change research includes alternative possible trends for socioeconomic development called Shared Socioeconomic Pathways (SSPs). The SSPs bear some similarities to other scenarios used for global change research, but they also have important differences. Like the IPCC Special Report on Emissions Scenarios or the Millennium Ecosystem Assessment, SSPs are defined by a scenario logic consisting of two axes. However, these axes define SSPs with respect to their location in an outcome space for challenges to mitigation and to adaptation rather than by their drivers. Open questions for the SSPs include what their drivers are and how the time dimension could be interpreted with the outcomes space. We present a new analytical approach for addressing both questions by studying large numbers of scenarios produced by an integrated assessment model, IMACLIM-R. We systematically generated 432 scenarios and used the SSP framework to classify them by typology. We then analyzed them dynamically, tracing their evolution through the SSP challenges space at annual time steps over the period 2010-2090. Through this approach, we found that many scenarios do not remain fixed to a particular SSP domain; they drift from one domain to another. In papers describing the framework for new scenarios, SSPs are envisioned as hypothetical (counter-factual) reference scenarios that remain fixed in one domain over some time period of interest. However, we conclude that it may be important to also research scenarios that shift across SSP domains. This is relevant for another open question, which is what scenarios are important to explore given their consequences. Through a data mining technique, we uncovered prominent drivers for scenarios that shift across SSP domains. Scenarios with different challenges for adaptation and mitigation (that is, mitigation and adaptation challenges that are not co-varying) were found to be the least stable, and the following

  12. Evolution.

    ERIC Educational Resources Information Center

    Mayr, Ernst

    1978-01-01

    Traces the history of evolution theory from Lamarck and Darwin to the present. Discusses natural selection in detail. Suggests that, besides biological evolution, there is also a cultural evolution which is more rapid than the former. (MA)

  13. Feeding the Elite: The Evolution of Elite Pathways from Star High Schools to Elite Universities

    ERIC Educational Resources Information Center

    LeTendre, Gerald K.; Gonzalez, Roger Geertz; Nomi, Takako

    2006-01-01

    During the last 50 years, private "feeder" schools in Japan came to dominate entry into elite colleges. Intense organizational competition shaped the organizational environment and changed the pathways available to social elites. Compared to Japan, elite private feeders in the US have failed to dominate pathways into elite colleges. In…

  14. Genetic basis of stage-specific melanism: a putative role for a cysteine sulfinic acid decarboxylase in insect pigmentation.

    PubMed

    Saenko, S V; Jerónimo, M A; Beldade, P

    2012-06-01

    Melanism, the overall darkening of the body, is a widespread form of animal adaptation to particular environments, and includes bookcase examples of evolution by natural selection, such as industrial melanism in the peppered moth. The major components of the melanin biosynthesis pathway have been characterized in model insects, but little is known about the genetic basis of life-stage specific melanism such as cases described in some lepidopteran species. Here, we investigate two melanic mutations of Bicyclus anynana butterflies, called Chocolate and melanine, that exclusively affect pigmentation of the larval and adult stages, respectively. Our analysis of Mendelian segregation patterns reveals that the larval and adult melanic phenotypes are due to alleles at different, independently segregating loci. Our linkage mapping analysis excludes the pigmentation candidate gene black as the melanine locus, and implicates a gene encoding a putative pyridoxal phosphate-dependant cysteine sulfinic acid decarboxylase as the Chocolate locus. We show variation in coding sequence and in expression levels for this candidate larval melanism locus. This is the first study that suggests a biological function for this gene in insects. Our findings open up exciting opportunities to study the role of this locus in the evolution of adaptive variation in pigmentation, and the uncoupling of regulation of pigment biosynthesis across developmental stages with different ecologies and pressures on body coloration.

  15. Genetic basis of stage-specific melanism: a putative role for a cysteine sulfinic acid decarboxylase in insect pigmentation

    PubMed Central

    Saenko, S V; Jerónimo, M A; Beldade, P

    2012-01-01

    Melanism, the overall darkening of the body, is a widespread form of animal adaptation to particular environments, and includes bookcase examples of evolution by natural selection, such as industrial melanism in the peppered moth. The major components of the melanin biosynthesis pathway have been characterized in model insects, but little is known about the genetic basis of life-stage specific melanism such as cases described in some lepidopteran species. Here, we investigate two melanic mutations of Bicyclus anynana butterflies, called Chocolate and melanine, that exclusively affect pigmentation of the larval and adult stages, respectively. Our analysis of Mendelian segregation patterns reveals that the larval and adult melanic phenotypes are due to alleles at different, independently segregating loci. Our linkage mapping analysis excludes the pigmentation candidate gene black as the melanine locus, and implicates a gene encoding a putative pyridoxal phosphate-dependant cysteine sulfinic acid decarboxylase as the Chocolate locus. We show variation in coding sequence and in expression levels for this candidate larval melanism locus. This is the first study that suggests a biological function for this gene in insects. Our findings open up exciting opportunities to study the role of this locus in the evolution of adaptive variation in pigmentation, and the uncoupling of regulation of pigment biosynthesis across developmental stages with different ecologies and pressures on body coloration. PMID:22234245

  16. A single gene causes an interspecific difference in pigmentation in Drosophila.

    PubMed

    Ahmed-Braimah, Yasir H; Sweigart, Andrea L

    2015-05-01

    The genetic basis of species differences remains understudied. Studies in insects have contributed significantly to our understanding of morphological evolution. Pigmentation traits in particular have received a great deal of attention and several genes in the insect pigmentation pathway have been implicated in inter- and intraspecific differences. Nonetheless, much remains unknown about many of the genes in this pathway and their potential role in understudied taxa. Here we genetically analyze the puparium color difference between members of the virilis group of Drosophila. The puparium of Drosophila virilis is black, while those of D. americana, D. novamexicana, and D. lummei are brown. We used a series of backcross hybrid populations between D. americana and D. virilis to map the genomic interval responsible for the difference between this species pair. First, we show that the pupal case color difference is caused by a single Mendelizing factor, which we ultimately map to an ∼11-kb region on chromosome 5. The mapped interval includes only the first exon and regulatory region(s) of the dopamine N-acetyltransferase gene (Dat). This gene encodes an enzyme that is known to play a part in the insect pigmentation pathway. Second, we show that this gene is highly expressed at the onset of pupation in light brown taxa (D. americana and D. novamexicana) relative to D. virilis, but not in the dark brown D. lummei. Finally, we examine the role of Dat in adult pigmentation between D. americana (heavily melanized) and D. novamexicana (lightly melanized) and find no discernible effect of this gene in adults. Our results demonstrate that a single gene is entirely or almost entirely responsible for a morphological difference between species.

  17. Ion transport in pigmentation

    PubMed Central

    Bellono, Nicholas W.; Oancea, Elena V.

    2014-01-01

    Skin melanocytes and ocular pigment cells contain specialized organelles called melanosomes, which are responsible for the synthesis of melanin, the major pigment in mammals. Defects in the complex mechanisms involved in melanin synthesis and regulation result in vision and pigmentation deficits, impaired development of the visual system,, and increased susceptibility to skin and eye cancers. Ion transport across cellular membranes is critical for many biological processes, including pigmentation, but the molecular mechanisms by which it regulates melanin synthesis, storage, and transfer are not understood. In this review we first discuss ion channels and transporters that function at the plasma membrane of melanocytes; in the second part we consider ion transport across the membrane of intracellular organelles, with emphasis on melanosomes. We discuss recently characterized lysosomal and endosomal ion channels and transporters associated with pigmentation phenotypes. We then review the evidence for melanosomal channels and transporters critical for pigmentation, discussing potential molecular mechanisms mediating their function. The studies investigating ion transport in pigmentation physiology open new avenues for future research and could reveal novel molecular mechanisms underlying melanogenesis. PMID:25034214

  18. Ion transport in pigmentation.

    PubMed

    Bellono, Nicholas W; Oancea, Elena V

    2014-12-01

    Skin melanocytes and ocular pigment cells contain specialized organelles called melanosomes, which are responsible for the synthesis of melanin, the major pigment in mammals. Defects in the complex mechanisms involved in melanin synthesis and regulation result in vision and pigmentation deficits, impaired development of the visual system, and increased susceptibility to skin and eye cancers. Ion transport across cellular membranes is critical for many biological processes, including pigmentation, but the molecular mechanisms by which it regulates melanin synthesis, storage, and transfer are not understood. In this review we first discuss ion channels and transporters that function at the plasma membrane of melanocytes; in the second part we consider ion transport across the membrane of intracellular organelles, with emphasis on melanosomes. We discuss recently characterized lysosomal and endosomal ion channels and transporters associated with pigmentation phenotypes. We then review the evidence for melanosomal channels and transporters critical for pigmentation, discussing potential molecular mechanisms mediating their function. The studies investigating ion transport in pigmentation physiology open new avenues for future research and could reveal novel molecular mechanisms underlying melanogenesis.

  19. Evolution of the Tetrapyrrole Biosynthetic Pathway in Secondary Algae: Conservation, Redundancy and Replacement

    PubMed Central

    Horák, Aleš; Oborník, Miroslav

    2016-01-01

    Tetrapyrroles such as chlorophyll and heme are indispensable for life because they are involved in energy fixation and consumption, i.e. photosynthesis and oxidative phosphorylation. In eukaryotes, the tetrapyrrole biosynthetic pathway is shaped by past endosymbioses. We investigated the origins and predicted locations of the enzymes of the heme pathway in the chlorarachniophyte Bigelowiella natans, the cryptophyte Guillardia theta, the “green” dinoflagellate Lepidodinium chlorophorum, and three dinoflagellates with diatom endosymbionts (“dinotoms”): Durinskia baltica, Glenodinium foliaceum and Kryptoperidinium foliaceum. Bigelowiella natans appears to contain two separate heme pathways analogous to those found in Euglena gracilis; one is predicted to be mitochondrial-cytosolic, while the second is predicted to be plastid-located. In the remaining algae, only plastid-type tetrapyrrole synthesis is present, with a single remnant of the mitochondrial-cytosolic pathway, a ferrochelatase of G. theta putatively located in the mitochondrion. The green dinoflagellate contains a single pathway composed of mostly rhodophyte-origin enzymes, and the dinotoms hold two heme pathways of apparently plastidal origin. We suggest that heme pathway enzymes in B. natans and L. chlorophorum share a predominantly rhodophytic origin. This implies the ancient presence of a rhodophyte-derived plastid in the chlorarachniophyte alga, analogous to the green dinoflagellate, or an exceptionally massive horizontal gene transfer. PMID:27861576

  20. Loss of the six3/6 controlling pathways might have resulted in pinhole-eye evolution in Nautilus.

    PubMed

    Ogura, Atsushi; Yoshida, Masa-aki; Moritaki, Takeya; Okuda, Yuki; Sese, Jun; Shimizu, Kentaro K; Sousounis, Konstantinos; Tsonis, Panagiotis A

    2013-01-01

    Coleoid cephalopods have an elaborate camera eye whereas nautiloids have primitive pinhole eye without lens and cornea. The Nautilus pinhole eye provides a unique example to explore the module of lens formation and its evolutionary mechanism. Here, we conducted an RNA-seq study of developing eyes of Nautilus and pygmy squid. First, we found that evolutionary distances from the common ancestor to Nautilus or squid are almost the same. Although most upstream eye development controlling genes were expressed in both species, six3/6 that are required for lens formation in vertebrates was not expressed in Nautilus. Furthermore, many downstream target genes of six3/6 including crystallin genes and other lens protein related genes were not expressed in Nautilus. As six3/6 and its controlling pathways are widely conserved among molluscs other than Nautilus, the present data suggest that deregulation of the six3/6 pathway led to the pinhole eye evolution in Nautilus.

  1. Learning from input and memory evolution: Points of vulnerability on a pathway to mastery in word learning

    PubMed Central

    Storkel, Holly L.

    2014-01-01

    Word learning consists of at least two neurocognitive processes: learning from input during training and memory evolution during gaps between training sessions. Fine-grained analysis of word learning by normal adults provides evidence that learning from input is swift and stable, whereas memory evolution is a point of potential vulnerability on the pathway to mastery. Moreover, success during learning from input is linked to positive outcomes from memory evolution. These two neurocognitive processes can be overlaid on to components of clinical treatment with within-session variables (i.e., dose form and dose) potentially linked to learning from input and between-session variables (i.e., dose frequency) linked to memory evolution. Collecting data at the beginning and end of a treatment session can be used to identify the point of vulnerability in word learning for a given client and the appropriate treatment component can then be adjusted to improve the client’s word learning. Two clinical cases are provided to illustrate this approach. PMID:25539474

  2. Defense mechanisms against herbivory in Picea: sequence evolution and expression regulation of gene family members in the phenylpropanoid pathway

    PubMed Central

    2011-01-01

    Background In trees, a substantial amount of carbon is directed towards production of phenolics for development and defense. This metabolic pathway is also a major factor in resistance to insect pathogens in spruce. In such gene families, environmental stimuli may have an important effect on the evolutionary fate of duplicated genes, and different expression patterns may indicate functional diversification. Results Gene families in spruce (Picea) have expanded to superfamilies, including O-methyltransferases, cytochrome-P450, and dirigents/classIII-peroxidases. Neo-functionalization of superfamily members from different clades is reflected in expression diversification. Genetical genomics can provide new insights into the genetic basis and evolution of insect resistance in plants. Adopting this approach, we merged genotype data (252 SNPs in a segregating pedigree), gene expression levels (for 428 phenylpropanoid-related genes) and measures of susceptibility to Pissodes stobi, using a partial-diallel crossing-design with white spruce (Picea glauca). Thirty-eight expressed phenylpropanoid-related genes co-segregated with weevil susceptibility, indicating either causative or reactive effects of these genes to weevil resistance. We identified eight regulatory genomic regions with extensive overlap of quantitative trait loci from susceptibility and growth phenotypes (pQTLs) and expression QTL (eQTL) hotspots. In particular, SNPs within two different CCoAOMT loci regulate phenotypic variation from a common set of 24 genes and three resistance traits. Conclusions Pest resistance was associated with individual candidate genes as well as with trans-regulatory hotspots along the spruce genome. Our results showed that specific genes within the phenylpropanoid pathway have been duplicated and diversified in the conifer in a process fundamentally different from short-lived angiosperm species. These findings add to the information about the role of the phenylpropanoid pathway in

  3. Pigmentation in Xiphophorus: an emerging system in ecological and evolutionary genetics.

    PubMed

    Culumber, Zachary W

    2014-02-01

    The genus Xiphophorus has great potential to contribute to the study of vertebrate pigmentation and elucidating the relative influence of ecology, physiology, and behavior on evolution at the molecular level. More importantly, the association between pigmentation and a functional oncogene offers the potential to understand the evolution and maintenance of cancer-causing genetic elements. Using criteria laid out recently in the literature, I demonstrate the power of the Xiphophorus system for studying pigment evolution through integrative organismal biology. Using the most recent phylogeny, the phylogenetic distribution of several important pigmentation loci are reevaluated. I then review support for existing hypotheses of the functional importance of pigmentation. Finally, new observations and hypotheses regarding some of the characteristics of pigment patterns in natural populations and open questions and future directions in the study of the evolution of these traits are discussed.

  4. Bis-Retinoid A2E Induces an Increase of Basic Fibroblast Growth Factor via Inhibition of Extracellular Signal-Regulated Kinases 1/2 Pathway in Retinal Pigment Epithelium Cells and Facilitates Phagocytosis

    PubMed Central

    Balmer, Delphine; Bapst-Wicht, Linda; Pyakurel, Aswin; Emery, Martine; Nanchen, Natacha; Bochet, Christian G.; Roduit, Raphael

    2017-01-01

    Age-related macular degeneration (ARMD) is the leading cause of vision loss in developed countries. Hallmarks of the disease are well known; indeed, this pathology is characterized by lipofuscin accumulation, is principally composed of lipid-containing residues of lysosomal digestion. The N-retinyl-N-retinylidene ethanolamine (A2E) retinoid which is thought to be a cytotoxic component for RPE is the best-characterized component of lipofuscin so far. Even if no direct correlation between A2E spatial distribution and lipofuscin fluorescence has been established in aged human RPE, modified forms or metabolites of A2E could be involved in ARMD pathology. Mitogen-activated protein kinase (MAPK) pathways have been involved in many pathologies, but not in ARMD. Therefore, we wanted to analyze the effects of A2E on MAPKs in polarized ARPE19 and isolated mouse RPE cells. We showed that long-term exposure of polarized ARPE19 cells to low A2E dose induces a strong decrease of the extracellular signal-regulated kinases' (ERK1/2) activity. In addition, we showed that A2E, via ERK1/2 decrease, induces a significant decrease of the retinal pigment epithelium-specific protein 65 kDa (RPE65) expression in ARPE19 cells and isolated mouse RPE. In the meantime, we showed that the decrease of ERK1/2 activity mediates an increase of basic fibroblast growth factor (bFGF) mRNA expression and secretion that induces an increase in phagocytosis via a paracrine effect. We suggest that the accumulation of deposits coming from outer segments (OS) could be explained by both an increase of bFGF-induced phagocytosis and by the decrease of clearance by A2E. The bFGF angiogenic protein may therefore be an attractive target to treat ARMD. PMID:28298893

  5. Recreating a functional ancestral archosaur visual pigment.

    PubMed

    Chang, Belinda S W; Jönsson, Karolina; Kazmi, Manija A; Donoghue, Michael J; Sakmar, Thomas P

    2002-09-01

    The ancestors of the archosaurs, a major branch of the diapsid reptiles, originated more than 240 MYA near the dawn of the Triassic Period. We used maximum likelihood phylogenetic ancestral reconstruction methods and explored different models of evolution for inferring the amino acid sequence of a putative ancestral archosaur visual pigment. Three different types of maximum likelihood models were used: nucleotide-based, amino acid-based, and codon-based models. Where possible, within each type of model, likelihood ratio tests were used to determine which model best fit the data. Ancestral reconstructions of the ancestral archosaur node using the best-fitting models of each type were found to be in agreement, except for three amino acid residues at which one reconstruction differed from the other two. To determine if these ancestral pigments would be functionally active, the corresponding genes were chemically synthesized and then expressed in a mammalian cell line in tissue culture. The expressed artificial genes were all found to bind to 11-cis-retinal to yield stable photoactive pigments with lambda(max) values of about 508 nm, which is slightly redshifted relative to that of extant vertebrate pigments. The ancestral archosaur pigments also activated the retinal G protein transducin, as measured in a fluorescence assay. Our results show that ancestral genes from ancient organisms can be reconstructed de novo and tested for function using a combination of phylogenetic and biochemical methods.

  6. Oxygen and hydrogen peroxide in the early evolution of life on earth: in silico comparative analysis of biochemical pathways.

    PubMed

    Slesak, Ireneusz; Slesak, Halina; Kruk, Jerzy

    2012-08-01

    In the Universe, oxygen is the third most widespread element, while on Earth it is the most abundant one. Moreover, oxygen is a major constituent of all biopolymers fundamental to living organisms. Besides O(2), reactive oxygen species (ROS), among them hydrogen peroxide (H(2)O(2)), are also important reactants in the present aerobic metabolism. According to a widely accepted hypothesis, aerobic metabolism and many other reactions/pathways involving O(2) appeared after the evolution of oxygenic photosynthesis. In this study, the hypothesis was formulated that the Last Universal Common Ancestor (LUCA) was at least able to tolerate O(2) and detoxify ROS in a primordial environment. A comparative analysis was carried out of a number of the O(2)-and H(2)O(2)-involving metabolic reactions that occur in strict anaerobes, facultative anaerobes, and aerobes. The results indicate that the most likely LUCA possessed O(2)-and H(2)O(2)-involving pathways, mainly reactions to remove ROS, and had, at least in part, the components of aerobic respiration. Based on this, the presence of a low, but significant, quantity of H(2)O(2) and O(2) should be taken into account in theoretical models of the early Archean atmosphere and oceans and the evolution of life. It is suggested that the early metabolism involving O(2)/H(2)O(2) was a key adaptation of LUCA to already existing weakly oxic zones in Earth's primordial environment.

  7. The evolution of the TOR pathway and its role in cancer.

    PubMed

    Beauchamp, E M; Platanias, L C

    2013-08-22

    The target of rapamycin (TOR) pathway is highly conserved among eukaryotes and has evolved to couple nutrient sensing to cellular growth. TOR is found in two distinct signaling complexes in cells, TOR complex 1 (TORC1) and TOR complex 2 (TORC2). These complexes are differentially regulated and act as effectors for the generation of signals that drive diverse cellular processes such as growth, proliferation, protein synthesis, rearrangement of the cytoskeleton, autophagy, metabolism and survival. Mammalian TOR (mTOR) is very important for development in embryos, while in adult organisms it is linked to aging and lifespan effects. In humans, the mTOR pathway is implicated in the tumorigenesis of multiple cancer types and its deregulation is associated with familial cancer syndromes. Because of its high biological relevance, different therapeutic strategies have been developed to target this signaling cascade, resulting in the emergence of unique pharmacological inhibitors that are either already approved for use in clinical oncology or currently under preclinical or clinical development. Multimodal treatment strategies that simultaneously target multiple nodes of the pathway and/or negative feedback regulatory loops may ultimately provide the best therapeutic advantage in targeting this pathway for the treatment of malignancies.

  8. RNA-Directed DNA Methylation: The Evolution of a Complex Epigenetic Pathway in Flowering Plants.

    PubMed

    Matzke, Marjori A; Kanno, Tatsuo; Matzke, Antonius J M

    2015-01-01

    RNA-directed DNA methylation (RdDM) is an epigenetic process in plants that involves both short and long noncoding RNAs. The generation of these RNAs and the induction of RdDM rely on complex transcriptional machineries comprising two plant-specific, RNA polymerase II (Pol II)-related RNA polymerases known as Pol IV and Pol V, as well as a host of auxiliary factors that include both novel and refashioned proteins. We present current views on the mechanism of RdDM with a focus on evolutionary innovations that occurred during the transition from a Pol II transcriptional pathway, which produces mRNA precursors and numerous noncoding RNAs, to the Pol IV and Pol V pathways, which are specialized for RdDM and gene silencing. We describe recently recognized deviations from the canonical RdDM pathway, discuss unresolved issues, and speculate on the biological significance of RdDM for flowering plants, which have a highly developed Pol V pathway.

  9. Surprising Arginine Biosynthesis: a Reappraisal of the Enzymology and Evolution of the Pathway in Microorganisms

    PubMed Central

    Xu, Ying; Labedan, Bernard; Glansdorff, Nicolas

    2007-01-01

    Summary: Major aspects of the pathway of de novo arginine biosynthesis via acetylated intermediates in microorganisms must be revised in light of recent enzymatic and genomic investigations. The enzyme N-acetylglutamate synthase (NAGS), which used to be considered responsible for the first committed step of the pathway, is present in a limited number of bacterial phyla only and is absent from Archaea. In many Bacteria, shorter proteins related to the Gcn5-related N-acetyltransferase family appear to acetylate l-glutamate; some are clearly similar to the C-terminal, acetyl-coenzyme A (CoA) binding domain of classical NAGS, while others are more distantly related. Short NAGSs can be single gene products, as in Mycobacterium spp. and Thermus spp., or fused to the enzyme catalyzing the last step of the pathway (argininosuccinase), as in members of the Alteromonas-Vibrio group. How these proteins bind glutamate remains to be determined. In some Bacteria, a bifunctional ornithine acetyltransferase (i.e., using both acetylornithine and acetyl-CoA as donors of the acetyl group) accounts for glutamate acetylation. In many Archaea, the enzyme responsible for glutamate acetylation remains elusive, but possible connections with a novel lysine biosynthetic pathway arose recently from genomic investigations. In some Proteobacteria (notably Xanthomonadaceae) and Bacteroidetes, the carbamoylation step of the pathway appears to involve N-acetylornithine or N-succinylornithine rather than ornithine. The product N-acetylcitrulline is deacetylated by an enzyme that is also involved in the provision of ornithine from acetylornithine; this is an important metabolic function, as ornithine itself can become essential as a source of other metabolites. This review insists on the biochemical and evolutionary implications of these findings. PMID:17347518

  10. Competition between anthocyanin and flavonol biosynthesis produces spatial pattern variation of floral pigments between Mimulus species

    PubMed Central

    Yuan, Yao-Wu; Rebocho, Alexandra B.; Sagawa, Janelle M.; Stanley, Lauren E.; Bradshaw, Harvey D.

    2016-01-01

    Flower color patterns have long served as a model for developmental genetics because pigment phenotypes are visually striking, yet generally not required for plant viability, facilitating the genetic analysis of color and pattern mutants. The evolution of novel flower colors and patterns has played a key role in the adaptive radiation of flowering plants via their specialized interactions with different pollinator guilds (e.g., bees, butterflies, birds), motivating the search for allelic differences affecting flower color pattern in closely related plant species with different pollinators. We have identified LIGHT AREAS1 (LAR1), encoding an R2R3-MYB transcription factor, as the causal gene underlying the spatial pattern variation of floral anthocyanin pigmentation between two sister species of monkeyflower: the bumblebee-pollinated Mimulus lewisii and the hummingbird-pollinated Mimulus cardinalis. We demonstrated that LAR1 positively regulates FLAVONOL SYNTHASE (FLS), essentially eliminating anthocyanin biosynthesis in the white region (i.e., light areas) around the corolla throat of M. lewisii flowers by diverting dihydroflavonol into flavonol biosynthesis from the anthocyanin pigment pathway. FLS is preferentially expressed in the light areas of the M. lewisii flower, thus prepatterning the corolla. LAR1 expression in M. cardinalis flowers is much lower than in M. lewisii, explaining the unpatterned phenotype and recessive inheritance of the M. cardinalis allele. Furthermore, our gene-expression analysis and genetic mapping results suggest that cis-regulatory change at the LAR1 gene played a critical role in the evolution of different pigmentation patterns between the two species. PMID:26884205

  11. Evolution of hydrological pathways in engineered hillslopes due to soil and vegetation development

    NASA Astrophysics Data System (ADS)

    Appels, Willemijn M.; Ireson, Andrew M.; McDonnell, Jeffrey J.; Barbour, S. Lee

    2015-04-01

    The structure and hydraulic properties of soils and bedrock within a hillslope combined with the timing and rates of water availability control the partitioning of precipitation into vertical and lateral flowpaths. In natural hillslope sites, heterogeneity in both soil texture and structure are the result of long-term landscape evolution processes and consequently can be assumed to be static relative to the timescale of rainfall-runoff processes. However; engineered hillslopes, constructed commonly as reclamation covers overlying mine waste, have been observed to undergo rapid changes in hydraulic properties over relatively short timescales (i.e. 3-5 years) as a result of weathering (e.g. freeze-thaw and wet-dry cycles) and vegetation growth (e.g. increasing rooting depth and density). Rainfall-runoff responses on such hillslopes would therefore not only be expected to reflect seasonal dynamics, but also the evolution of the system from a relatively homogeneous initial condition to a system with increasing heterogeneity of soil texture and structure. We present results of a combined field and modeling study of three prototype soil covers on a saline-sodic shale overburden dump at the Syncrude Canada Ltd. Mildred Lake mine, north of Fort McMurray, Canada. Since their construction in 1999, soil properties, hydrological response to atmospheric and vegetative demands, and vegetation properties have been extensively monitored. The three covers have undergone substantial evolution due to freeze-thaw processes and aggrading vegetation. In this work, we quantify hydrological processes in the reclamation covers, focusing on inter- and intra-annual patterns. To this purpose we analyzed the long-term hydrometric data with field sampling of the distribution of salts and the stable isotopes of water within soil water and subsurface flow in the base of the cover. We use a 2D Hydrus model to explore the co-evolution of soil and vegetation and quantify its effect on flow

  12. Planarian Hh signaling regulates regeneration polarity and links Hh pathway evolution to cilia.

    PubMed

    Rink, Jochen C; Gurley, Kyle A; Elliott, Sarah A; Sánchez Alvarado, Alejandro

    2009-12-04

    The Hedgehog (Hh) signaling pathway plays multiple essential roles during metazoan development, homeostasis, and disease. Although core protein components are highly conserved, the variations in Hh signal transduction mechanisms exhibited by existing model systems (Drosophila, fish, and mammals) are difficult to understand. We characterized the Hh pathway in planarians. Hh signaling is essential for establishing the anterior/posterior axis during regeneration by modulating wnt expression. Moreover, RNA interference methods to reduce signal transduction proteins Cos2/Kif27/Kif7, Fused, or Iguana do not result in detectable Hh signaling defects; however, these proteins are essential for planarian ciliogenesis. Our study expands the understanding of Hh signaling in the animal kingdom and suggests an ancestral mechanistic link between Hh signaling and the function of cilia.

  13. The origin of the supernumerary subunits and assembly factors of complex I: A treasure trove of pathway evolution.

    PubMed

    Elurbe, Dei M; Huynen, Martijn A

    2016-07-01

    We review and document the evolutionary origin of all complex I assembly factors and nine supernumerary subunits from protein families. Based on experimental data and the conservation of critical residues we identify a spectrum of protein function conservation between the complex I representatives and their non-complex I homologs. This spectrum ranges from proteins that have retained their molecular function but in which the substrate specificity may have changed or have become more specific, like NDUFAF5, to proteins that have lost their original molecular function and critical catalytic residues like NDUFAF6. In between are proteins that have retained their molecular function, which however appears unrelated to complex I, like ACAD9, or proteins in which amino acids of the active site are conserved but for which no enzymatic activity has been reported, like NDUFA10. We interpret complex I evolution against the background of molecular evolution theory. Complex I supernumerary subunits and assembly factors appear to have been recruited from proteins that are mitochondrial and/or that are expressed when complex I is active. Within the evolution of complex I and its assembly there are many cases of neofunctionalization after gene duplication, like ACAD9 and TMEM126B, one case of subfunctionalization: ACPM1 and ACPM2 in Yarrowia lipolytica, and one case in which a complex I protein itself appears to have been the source of a new protein from another complex: NDUFS6 gave rise to cytochrome c oxidase subunit COX4/COX5b. Complex I and its assembly can therewith be regarded as a treasure trove for pathway evolution. This article is part of a Special Issue entitled Respiratory complex I, edited by Volker Zickermann and Ulrich Brandt.

  14. The evolution of water and solute fluxes and pathways in post-constructional volcanic landscapes of the Hawaiian Islands

    NASA Astrophysics Data System (ADS)

    Derry, L. A.; Schopka, H. H.

    2011-12-01

    Post-eruptive volcanic landscapes evolve rapidly in response to erosion, re-vegetation, and pedogenesis. The Hawaiian islands offer a time series to study the evolution of surface processes on a uniform lithology and under spatially varying but well-characterized climates. Young surfaces retain constructional topography largely controlled by the most recent lava flows and/or ash deposits. Young surfaces such as found on Mauna Loa (O 102 - 103 yrs) are highly permeable and surface runoff is rare or absent, even under conditions of high rainfall. We hypothesize that the development of soil is a key factor in reducing vertical infiltration rates and promoting lateral flow of water. Stream channelization begins with control by constructional topography and in some cases major faults or fracture zone. In areas with positive water balance stream erosion leads to rapid channel formation. On the windward side of Mauna Kea (O 104 - 105 yrs) stream incision into the shield topography is much more pronounced than on adjacent Mauna Loa surfaces. Flank collapse (e.g. windward Kohala, ≥ 105 yrs) leaves hanging valleys and drives deep canyon formation. On all of the Hawaiian islands direct submarine groundwater discharge (SGD) to the oceans is important. The ratio of water transported to the oceans as stream discharge (Q) vs SGD increases with surface age and incision, from near zero on Mauna Loa to > 1 on Kohala. Island wide, SGD ≈ 3.5 - 4x Q. The evolution of water pathways influences weathering fluxes to the oceans. Ground water from Hawaii has significantly larger concentrations of weathering-derived solutes than does stream water. This should result from longer path length and contact time, which increase interaction with reactive mineral surfaces, but the detailed controls on solute chemistry remain uncertain. Island-wide, the flux ratio of weathering solutes in SGD vs Q is near 15. SGDA is the dominant pathway for the delivery of silicate mineral weathering products to

  15. Anthocyanins. Plant pigments and beyond.

    PubMed

    Santos-Buelga, Celestino; Mateus, Nuno; De Freitas, Victor

    2014-07-23

    Anthocyanins are plant pigments widespread in nature. They play relevant roles in plant propagation and ecophysiology and plant defense mechanisms and are responsible for the color of fruits and vegetables. A large number of novel anthocyanin structures have been identified, including new families such as pyranoanthocyanins or anthocyanin oligomers; their biosynthesis pathways have been elucidated, and new plants with "a la carte" colors have been created by genetic engineering. Furthermore, evidence about their benefits in human health has accumulated, and processes of anthocyanin absorption and biotransformation in the human organism have started to be ascertained. These advances in anthocyanin research were revised in the Seventh International Workshop on Anthocyanins that took place in Porto (Portugal) on September 9-11, 2013. Some selected papers are collected in this special issue, where aspects such as anthocyanin accumulation in plants, relationship with color expression, stability in plants and food, and bioavailability or biological activity are revised.

  16. Pigmented central neurocytoma.

    PubMed

    Kiehl, Tim-Rasmus; Kalkanis, Steven N; Louis, David N

    2004-06-01

    Central neurocytoma is a low-grade neuronal neoplasm that occurs most often within the lateral ventricles. We report the case of a 60-year-old woman who presented with gait problems, headache and memory loss. Preoperative evaluation demonstrated a heterogeneous, hypervascular and partially cystic mass in the left lateral ventricle. Histopathological examination revealed characteristic features of central neurocytoma, including immunoreactivity for synaptophysin, as well as the unusual feature of abundant pigment in the cytoplasm of tumor cells. Special stains revealed iron, consistent with hemosiderin, but found no evidence of melanin or melanosomes. Previous reports of pigmented central neurocytoma have described the presence of lipofuscin or neuromelanin. To our knowledge, the present case represents the first example of pigmented central neurocytoma secondary to hemosiderin deposition.

  17. Transition dipole moments of the Qy band in photosynthetic pigments.

    PubMed

    Oviedo, M Belén; Sánchez, Cristián G

    2011-11-10

    From studying the time evolution of the single electron density matrix within a density functional tight-binding formalism we calculate the Q(y) transition dipole moments vector direction and strength for a series of important photosynthetic pigments. We obtain good agreement with first-principles and experimental results and provide insights into the detailed nature of these excitations from the time evolving populations of molecular orbitals involved as well as correlations between pigment chemistry and dipole strength.

  18. Biology of pigmentation

    SciTech Connect

    Parker, F.

    1981-01-01

    The many factors involved in the normal pigmentation of human skin are highly complex involving anatomic, biochemical, and genetic aspects of melanocytes in the skin and the influence of UV light and various hormones on the melanocytes. It is probably more than just coincidence that the melanocytes, which are of neurogenic origin, are so responsive to several trophic hormones produced in the brain. Understanding of the various factors involved in the normal pigmentary process is crucial to explaining the many alterations and anomalies in human pigmentation.

  19. Evolution under different storage conditions of anomalous blue coloration of Mozzarella cheese intentionally contaminated with a pigment-producing strain of Pseudomonas fluorescens.

    PubMed

    Cenci-Goga, B T; Karama, M; Sechi, P; Iulietto, M F; Novelli, S; Mattei, S

    2014-11-01

    Several widespread occurrences of anomalous blue coloration of Mozzarella cheese have been recorded in the United States and some European countries. Official laboratory analysis and health authorities have linked the occurrences to contamination of the processing water with strains of Pseudomonas fluorescens, although several experts questioned how to unequivocally link the blue color to the presence of the microorganism. To establish a method to determine whether a given Pseudomonas spp. strain is responsible for the defect and study the evolution of the coloration under different storage conditions, we developed an in vitro system for the evaluation of blue coloration of Mozzarella cheese intentionally contaminated with strains of P. fluorescens. The purpose of the system was to determine whether P.fluorescens strains, isolated from Mozzarella cheese with anomalous blue coloration, were able to reproduce the blue coloration under controlled experimental conditions. Thirty-six trials of experimental inoculation of Mozzarella cheese in different preservation liquids were conducted using various suspensions of P.fluorescens (P. fluorescens ATCC 13525, P.fluorescens CFBP 3150, and P. fluorescens 349 field strain isolated from blue-colored Mozzarella cheese) at different concentrations and incubated at different temperatures. Growth curves of all tested P.fluorescens strains demonstrated that after 3 d of incubation the concentration was generally >10(6) cfu/g of Mozzarella cheese incubated in either tryptic soy broth (control) or conditioning brine. Prolonged incubation for 5 d at either 20 °C or 8 °C led to concentrations up to 10(9) cfu/g of Mozzarella cheese incubated in tryptic soy broth and up to 10(8) cfu/g of Mozzarella cheese incubated in preservation liquid. All Mozzarella cheeses inoculated with the field strain of P. fluorescens, except those opened 1h after packaging and stored at 8 °C, showed the characteristic anomalous blue coloration, which

  20. Linoleic acid-induced expression of inducible nitric oxide synthase and cyclooxygenase II via p42/44 mitogen-activated protein kinase and nuclear factor-kappaB pathway in retinal pigment epithelial cells.

    PubMed

    Fang, I-Mo; Yang, Chang-Hao; Yang, Chung-May; Chen, Muh-Shy

    2007-11-01

    High linoleic acid (LA) intake is known to correlate with age-related macular degeneration (AMD), but the molecular mechanisms remain unclear. This study was conducted to investigate the effects of LA on expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase II (COX-2) and their associated signaling pathways in human retinal pigment epithelial (RPE) cells. ARPE-19 cells were treated with different concentrations of LA. Expressions of iNOS and COX-2 were examined using semiquantitative reverse transcription polymerase chain reaction (RT-PCR) and Western blot analysis. Concentrations of nitric oxide (NO) and prostaglandin E(2) (PGE(2)) in the culture medium were determined by enzyme-link immunosorbent assay (ELISA). Activation of p42/44, p38, JNK mitogen-activated protein kinase (MAPK) and nuclear factors (NF)-kappaB were evaluated by Western blot analysis and electrophoretic mobility shift assay (EMSA). We found that LA induced expression of iNOS and COX-2 in RPE cells at the mRNA and protein levels in a time-and dose-dependent manner. Upregulation of iNOS and COX-2 resulted in increased production of NO and PGE(2). Moreover, LA caused degradation of IkappaB and increased NF-kappaB DNA binding activity. Effects of LA-induced iNOS and COX-2 expression were inhibited by a NF-kappaB inhibitor, pyrrolidine dithiocarbamate (PDTC). LA activated p42/44, but not p38 or JNK MAPK. Inhibition of p42/44 activity by PD98059 significantly reduced LA-induced activation of NF-kappaB. Linoleic acid-induced expression of iNOS and COX-2 as well as PGE(2) and NO release in RPE cells were sequentially mediated through activation of p42/p44, MAPK, then NF-kappaB. These results may provide new insights into both mechanisms of LA action on RPE cells and pathogenesis of age-related macular degeneration.

  1. Oxygen and Hydrogen Peroxide in the Early Evolution of Life on Earth: In silico Comparative Analysis of Biochemical Pathways

    PubMed Central

    Ślesak, Halina; Kruk, Jerzy

    2012-01-01

    Abstract In the Universe, oxygen is the third most widespread element, while on Earth it is the most abundant one. Moreover, oxygen is a major constituent of all biopolymers fundamental to living organisms. Besides O2, reactive oxygen species (ROS), among them hydrogen peroxide (H2O2), are also important reactants in the present aerobic metabolism. According to a widely accepted hypothesis, aerobic metabolism and many other reactions/pathways involving O2 appeared after the evolution of oxygenic photosynthesis. In this study, the hypothesis was formulated that the Last Universal Common Ancestor (LUCA) was at least able to tolerate O2 and detoxify ROS in a primordial environment. A comparative analysis was carried out of a number of the O2-and H2O2-involving metabolic reactions that occur in strict anaerobes, facultative anaerobes, and aerobes. The results indicate that the most likely LUCA possessed O2-and H2O2-involving pathways, mainly reactions to remove ROS, and had, at least in part, the components of aerobic respiration. Based on this, the presence of a low, but significant, quantity of H2O2 and O2 should be taken into account in theoretical models of the early Archean atmosphere and oceans and the evolution of life. It is suggested that the early metabolism involving O2/H2O2 was a key adaptation of LUCA to already existing weakly oxic zones in Earth's primordial environment. Key Words: Hydrogen peroxide—Oxygen—Origin of life—Photosynthesis—Superoxide dismutase—Superoxide reductase. Astrobiology 12, 775–784. PMID:22970865

  2. Evolution of the New Pathway curriculum at Harvard Medical School: the new integrated curriculum.

    PubMed

    Dienstag, Jules L

    2011-01-01

    In 1985, Harvard Medical School adopted a "New Pathway" curriculum, based on active, adult learning through problem-based, faculty-facilitated small-group tutorials designed to promote lifelong skills of self-directed learning. Despite the successful integration of clinically relevant material in basic science courses, the New Pathway goals were confined primarily to the preclinical years. In addition, the shifting balance in the delivery of health care from inpatient to ambulatory settings limited the richness of clinical education in clinical clerkships, creating obstacles for faculty in their traditional roles as teachers. In 2006, Harvard Medical School adopted a more integrated curriculum based on four principles that emerged after half a decade of self-reflection and planning: (1) integrate the teaching of basic/population science and clinical medicine throughout the entire student experience; (2) reestablish meaningful and intensive faculty-student interactions and reengage the faculty; (3) develop a new model of clinical education that offers longitudinal continuity of patient experience, cross-disciplinary curriculum, faculty mentoring, and student evaluation; and (4) provide opportunities for all students to pursue an in-depth, faculty-mentored scholarly project. These principles of our New Integrated Curriculum reflect our vision for a curriculum that fosters a partnership between students and faculty in the pursuit of scholarship and leadership.

  3. Are changes in sulfate assimilation pathway needed for evolution of C4 photosynthesis?

    PubMed

    Weckopp, Silke C; Kopriva, Stanislav

    2014-01-01

    C4 photosynthesis characteristically features a cell-specific localization of enzymes involved in CO2 assimilation in bundle sheath cells (BSC) or mesophyll cells. Interestingly, enzymes of sulfur assimilation are also specifically present in BSC of maize and many other C4 species. This localization, however, could not be confirmed in C4 species of the genus Flaveria. It was, therefore, concluded that the bundle sheath localization of sulfate assimilation occurs only in C4 monocots. However, recently the sulfate assimilation pathway was found coordinately enriched in BSC of Arabidopsis, opening new questions about the significance of such cell-specific localization of the pathway. In addition, next generation sequencing revealed expression gradients of many genes from C3 to C4 species and mathematical modeling proposed a sequence of adaptations during the evolutionary path from C3 to C4. Indeed, such gradient, with higher expression of genes for sulfate reduction in C4 species, has been observed within the genus Flaveria. These new tools provide the basis for reexamining the intriguing question of compartmentalization of sulfur assimilation. Therefore, this review summarizes the findings on spatial separation of sulfur assimilation in C4 plants and Arabidopsis, assesses the information on sulfur assimilation provided by the recent transcriptomics data and discusses their possible impact on understanding this interesting feature of plant sulfur metabolism to find out whether changes in sulfate assimilation are part of a general evolutionary trajectory toward C4 photosynthesis.

  4. Parallel processing in the honeybee olfactory pathway: structure, function, and evolution.

    PubMed

    Rössler, Wolfgang; Brill, Martin F

    2013-11-01

    Animals face highly complex and dynamic olfactory stimuli in their natural environments, which require fast and reliable olfactory processing. Parallel processing is a common principle of sensory systems supporting this task, for example in visual and auditory systems, but its role in olfaction remained unclear. Studies in the honeybee focused on a dual olfactory pathway. Two sets of projection neurons connect glomeruli in two antennal-lobe hemilobes via lateral and medial tracts in opposite sequence with the mushroom bodies and lateral horn. Comparative studies suggest that this dual-tract circuit represents a unique adaptation in Hymenoptera. Imaging studies indicate that glomeruli in both hemilobes receive redundant sensory input. Recent simultaneous multi-unit recordings from projection neurons of both tracts revealed widely overlapping response profiles strongly indicating parallel olfactory processing. Whereas lateral-tract neurons respond fast with broad (generalistic) profiles, medial-tract neurons are odorant specific and respond slower. In analogy to "what-" and "where" subsystems in visual pathways, this suggests two parallel olfactory subsystems providing "what-" (quality) and "when" (temporal) information. Temporal response properties may support across-tract coincidence coding in higher centers. Parallel olfactory processing likely enhances perception of complex odorant mixtures to decode the diverse and dynamic olfactory world of a social insect.

  5. Neoproterozoic Oxygenation of Earth Surface Environments Reflected in the Late Evolution of the O2-Dependent Vitamin B12 Biosynthesis Pathway

    NASA Astrophysics Data System (ADS)

    Saito, M. A.; Bertrand, E. M.; Anbar, A.

    2008-12-01

    There are multiple lines of evidence for a significant rise of O2 in the Earth's atmosphere ~2.4 Ga. A second oxygenation event in the Neoproterozoic is not as well constrained. These changes in environmental redox affected the abundances of bioessential elements. Trace elements such as Co, Fe, and Ni were likely favored in the early evolution of metalloenzymes, prior to the first oxidation event. Consistent with this expectation, vitamin B12 is a Co-containing biomolecule whose biosynthesis is thought to have evolved prior to the origin of oxygenic photosynthesis and the first rise in O2. However, biochemical characterization of the many enzymes involved in B12 biosynthesis has revealed two distinct pathways: an O2-independent pathway and an O2-dependant pathway. The major difference between these pathways involves the timing of the insertion of Co. We examined the amino acid sequences of enzymes in the B12 biosynthesis pathway from a set of 100 phylogenetically diverse microbial genomes, focusing on enzymes exclusive to each pathway as well as enzymes shared by both. Molecular clock and phylogenetic analyses were performed on alignments of the sequences obtained from these study genomes. This approach focused on functional genes rather than the phylogeny of microbes in an attempt to understand the evolution of the pathway itself, rather than its presence in individual phylogenetic groups. Clear differences in age are apparent between representatives of each pathway. The O2-independent pathway and enzymes shared in both pathways show the most ancient last common ancestors. In contrast, the enzymes associated exclusively with the O2-dependent pathway diverged from a common ancestor less than a billion years ago. Phylogenetic analysis suggests that these enzymes were recruited from other biochemical pathways. From these results it seems likely that the evolution of the O2-dependent pathway occurred long after the initial evolution of the B12 biosynthesis. This

  6. Comparative genomic analysis of nine Sphingobium strains: Insights into their evolution and hexachlorocyclohexane (HCH) degradation pathways

    SciTech Connect

    Verma, Helianthous; Kumar, Roshan; Oldach, Phoebe; Sangwan, Naseer; Khurana, Jitendra P.; Gilbert, Jack A.; Lal, Rup

    2014-11-23

    Background: Sphingobium spp. are efficient degraders of a wide range of chlorinated and aromatic hydrocarbons. In particular, strains which harbour the lin pathway genes mediating the degradation of hexachlorocyclohexane (HCH) isomers are of interest due to the widespread persistence of this contaminant. Here, we examined the evolution and diversification of the lin pathway under the selective pressure of HCH, by comparing the draft genomes of six newly-sequenced Sphingobium spp. (strains LL03, DS20, IP26, HDIPO4, P25 and RL3) isolated from HCH dumpsites, with three existing genomes (S. indicum B90A, S. japonicum UT26S and Sphingobium sp. SYK6). Results: Efficient HCH degraders phylogenetically clustered in a closely related group comprising of UT26S, B90A, HDIPO4 and IP26, where HDIPO4 and IP26 were classified as subspecies with ANI value >98%. Less than 10% of the total gene content was shared among all nine strains, but among the eight HCH-associated strains, that is all except SYK6, the shared gene content jumped to nearly 25%. Genes associated with nitrogen stress response and two-component systems were found to be enriched. The strains also housed many xenobiotic degradation pathways other than HCH, despite the absence of these xenobiotics from isolation sources. In addition, these strains, although non-motile, but posses flagellar assembly genes. While strains HDIPO4 and IP26 contained the complete set of lin genes, DS20 was entirely devoid of lin genes (except linKLMN) whereas, LL03, P25 and RL3 were identified as lin deficient strains, as they housed incomplete lin pathways. Further, in HDIPO4, linA was found as a hybrid of two natural variants i.e., linA1 and linA2 known for their different enantioselectivity. In conclusion, the bacteria isolated from HCH dumpsites provide a natural testing ground to study variations in the lin system and their

  7. Genomic and Secondary Metabolite Analyses of Streptomyces sp. 2AW Provide Insight into the Evolution of the Cycloheximide Pathway

    PubMed Central

    Stulberg, Elizabeth R.; Lozano, Gabriel L.; Morin, Jesse B.; Park, Hyunjun; Baraban, Ezra G.; Mlot, Christine; Heffelfinger, Christopher; Phillips, Gillian M.; Rush, Jason S.; Phillips, Andrew J.; Broderick, Nichole A.; Thomas, Michael G.; Stabb, Eric V.; Handelsman, Jo

    2016-01-01

    The dearth of new antibiotics in the face of widespread antimicrobial resistance makes developing innovative strategies for discovering new antibiotics critical for the future management of infectious disease. Understanding the genetics and evolution of antibiotic producers will help guide the discovery and bioengineering of novel antibiotics. We discovered an isolate in Alaskan boreal forest soil that had broad antimicrobial activity. We elucidated the corresponding antimicrobial natural products and sequenced the genome of this isolate, designated Streptomyces sp. 2AW. This strain illustrates the chemical virtuosity typical of the Streptomyces genus, producing cycloheximide as well as two other biosynthetically unrelated antibiotics, neutramycin, and hygromycin A. Combining bioinformatic and chemical analyses, we identified the gene clusters responsible for antibiotic production. Interestingly, 2AW appears dissimilar from other cycloheximide producers in that the gene encoding the polyketide synthase resides on a separate part of the chromosome from the genes responsible for tailoring cycloheximide-specific modifications. This gene arrangement and our phylogenetic analyses of the gene products suggest that 2AW holds an evolutionarily ancestral lineage of the cycloheximide pathway. Our analyses support the hypothesis that the 2AW glutaramide gene cluster is basal to the lineage wherein cycloheximide production diverged from other glutarimide antibiotics. This study illustrates the power of combining modern biochemical and genomic analyses to gain insight into the evolution of antibiotic-producing microorganisms. PMID:27199910

  8. Genomic and Secondary Metabolite Analyses of Streptomyces sp. 2AW Provide Insight into the Evolution of the Cycloheximide Pathway.

    PubMed

    Stulberg, Elizabeth R; Lozano, Gabriel L; Morin, Jesse B; Park, Hyunjun; Baraban, Ezra G; Mlot, Christine; Heffelfinger, Christopher; Phillips, Gillian M; Rush, Jason S; Phillips, Andrew J; Broderick, Nichole A; Thomas, Michael G; Stabb, Eric V; Handelsman, Jo

    2016-01-01

    The dearth of new antibiotics in the face of widespread antimicrobial resistance makes developing innovative strategies for discovering new antibiotics critical for the future management of infectious disease. Understanding the genetics and evolution of antibiotic producers will help guide the discovery and bioengineering of novel antibiotics. We discovered an isolate in Alaskan boreal forest soil that had broad antimicrobial activity. We elucidated the corresponding antimicrobial natural products and sequenced the genome of this isolate, designated Streptomyces sp. 2AW. This strain illustrates the chemical virtuosity typical of the Streptomyces genus, producing cycloheximide as well as two other biosynthetically unrelated antibiotics, neutramycin, and hygromycin A. Combining bioinformatic and chemical analyses, we identified the gene clusters responsible for antibiotic production. Interestingly, 2AW appears dissimilar from other cycloheximide producers in that the gene encoding the polyketide synthase resides on a separate part of the chromosome from the genes responsible for tailoring cycloheximide-specific modifications. This gene arrangement and our phylogenetic analyses of the gene products suggest that 2AW holds an evolutionarily ancestral lineage of the cycloheximide pathway. Our analyses support the hypothesis that the 2AW glutaramide gene cluster is basal to the lineage wherein cycloheximide production diverged from other glutarimide antibiotics. This study illustrates the power of combining modern biochemical and genomic analyses to gain insight into the evolution of antibiotic-producing microorganisms.

  9. Time evolution and competing pathways in photodegradation of trifluralin and three of its major degradation products.

    PubMed

    Tagle, Martín G Sarmiento; Laura Salum, María; Buján, Elba I; Argüello, Gustavo A

    2005-11-01

    The herbicide trifluralin (I)(N,N-di-n-propyl-2,6-dinitro-4-trifluoromethylaniline) decomposes, by the action of UV-Vis light (lambda > 300 nm), to several products, the most important (because they give subsequent photochemical reactions) being N-n-propyl-2,6-dinitro-4-trifluoromethylaniline (VI), 2-ethyl-7-nitro-5-trifluoromethyl-1H-benzimidazole 3-oxide (VII) and 2,6-dinitro-4-trifluoromethylaniline (XII). The time evolution of degradation of trifluralin (I) and the aforementioned three main photoproducts was studied in water and acetonitrile as solvents. The pseudo-first order rate constants allow one to calculate the branching ratios for some of the reactions involved. The preference for either N-dealkylation or cyclization depends on the solvent employed. Dissolved oxygen accelerates the photodegradation, especially the dealkylation.

  10. Olfactory pathway of the hornet Vespa velutina: New insights into the evolution of the hymenopteran antennal lobe.

    PubMed

    Couto, Antoine; Lapeyre, Benoit; Thiéry, Denis; Sandoz, Jean-Christophe

    2016-08-01

    In the course of evolution, eusociality has appeared several times independently in Hymenoptera, within different families such as Apidae (bees), Formicidae (ants), and Vespidae (wasps and hornets), among others. The complex social organization of eusocial Hymenoptera relies on sophisticated olfactory communication systems. Whereas the olfactory systems of several bee and ant species have been well characterized, very little information is as yet available in Vespidae, although this family represents a highly successful insect group, displaying a wide range of life styles from solitary to eusocial. Using fluorescent labeling, confocal microscopy, and 3D reconstructions, we investigated the organization of the olfactory pathway in queens, workers, and males of the eusocial hornet Vespa velutina. First, we found that caste and sex dimorphism is weakly pronounced in hornets, with regard to both whole-brain morphology and antennal lobe organization, although several male-specific macroglomeruli are present. The V. velutina antennal lobe contains approximately 265 glomeruli (in females), grouped in nine conspicuous clusters formed by afferent tract subdivisions. As in bees and ants, hornets display a dual olfactory pathway, with two major efferent tracts, the medial and the lateral antennal lobe tracts (m- and l-ALT), separately arborizing two antennal lobe hemilobes and projecting to partially different regions of higher order olfactory centers. Finally, we found remarkable anatomical similarities in the glomerular cluster organizations among hornets, ants, and bees, suggesting the possible existence of homologies in the olfactory pathways of these eusocial Hymenoptera. We propose a common framework for describing AL compartmentalization across Hymenoptera and discuss possible evolutionary scenarios. J. Comp. Neurol. 524:2335-2359, 2016. © 2016 Wiley Periodicals, Inc.

  11. The neuroprogressive nature of major depressive disorder: pathways to disease evolution and resistance, and therapeutic implications.

    PubMed

    Moylan, S; Maes, M; Wray, N R; Berk, M

    2013-05-01

    In some patients with major depressive disorder (MDD), individual illness characteristics appear consistent with those of a neuroprogressive illness. Features of neuroprogression include poorer symptomatic, treatment and functional outcomes in patients with earlier disease onset and increased number and length of depressive episodes. In such patients, longer and more frequent depressive episodes appear to increase vulnerability for further episodes, precipitating an accelerating and progressive illness course leading to functional decline. Evidence from clinical, biochemical and neuroimaging studies appear to support this model and are informing novel therapeutic approaches. This paper reviews current knowledge of the neuroprogressive processes that may occur in MDD, including structural brain consequences and potential molecular mechanisms including the role of neurotransmitter systems, inflammatory, oxidative and nitrosative stress pathways, neurotrophins and regulation of neurogenesis, cortisol and the hypothalamic-pituitary-adrenal axis modulation, mitochondrial dysfunction and epigenetic and dietary influences. Evidence-based novel treatments informed by this knowledge are discussed.

  12. Evolution of the Chaperone/Usher Assembly Pathway: Fimbrial Classification Goes Greek†

    PubMed Central

    Nuccio, Sean-Paul; Bäumler, Andreas J.

    2007-01-01

    Summary: Many Proteobacteria use the chaperone/usher pathway to assemble proteinaceous filaments on the bacterial surface. These filaments can curl into fimbrial or nonfimbrial surface structures (e.g., a capsule or spore coat). This article reviews the phylogeny of operons belonging to the chaperone/usher assembly class to explore the utility of establishing a scheme for subdividing them into clades of phylogenetically related gene clusters. Based on usher amino acid sequence comparisons, our analysis shows that the chaperone/usher assembly class is subdivided into six major phylogenetic clades, which we have termed α-, β-, γ-, κ-, π-, and σ-fimbriae. Members of each clade share related operon structures and encode fimbrial subunits with similar protein domains. The proposed classification system offers a simple and convenient method for assigning newly discovered chaperone/usher systems to one of the six major phylogenetic groups. PMID:18063717

  13. Role of the 9-methyl group of retinal in cone visual pigments.

    PubMed

    Das, Joydip; Crouch, Rosalie K; Ma, Jian-xing; Oprian, Daniel D; Kono, Masahiro

    2004-05-11

    In rhodopsin, the 9-methyl group of retinal has previously been identified as being critical in linking the ligand isomerization with the subsequent protein conformational changes that result in the activation of its G protein, transducin. Here, we report studies on the role of this methyl group in the salamander rod and cone pigments. Pigments were generated by combining proteins expressed in COS cells with 11-cis 9-demethyl retinal, where the 9-methyl group on the polyene chain has been deleted. The absorption spectra of all pigments were blue-shifted. The red cone and blue cone/green rod pigments were unstable to hydroxylamine; whereas, the rhodopsin and UV cone pigments were stable. The lack of the 9-methyl group of the chromophore did not affect the ability of the red cone and blue cone/green rod pigments to activate transducin. On the other hand, with the rhodopsin and UV cone pigments, activation was diminished. Interestingly, the red cone pigment containing the retinal analogue remained active longer than the native pigment. Thus, the 9-methyl group of retinal is not important in the activation pathway of the red cone and blue cone/green rod pigments. However, for the red cone pigment, the 9-methyl group of retinal appears to be critical in the deactivation pathway.

  14. Combining natural and man-made DNA tracers to advance understanding of hydrologic flow pathway evolution

    NASA Astrophysics Data System (ADS)

    Dahlke, H. E.; Walter, M. T.; Lyon, S. W.; Rosqvist, G. N.

    2014-12-01

    Identifying and characterizing the sources, pathways and residence times of water and associated constituents is critical to developing improved understanding of watershed-stream connections and hydrological/ecological/biogeochemical models. To date the most robust information is obtained from integrated studies that combine natural tracers (e.g. isotopes, geochemical tracers) with controlled chemical tracer (e.g., bromide, dyes) or colloidal tracer (e.g., carboxilated microspheres, tagged clay particles, microorganisms) applications. In the presented study we explore how understanding of sources and flow pathways of water derived from natural tracer studies can be improved and expanded in space and time by simultaneously introducing man-made, synthetic DNA-based microtracers. The microtracer used were composed of polylactic acid (PLA) microspheres into which short strands of synthetic DNA and paramagnetic iron oxide nanoparticles are incorporated. Tracer experiments using both natural tracers and the DNA-based microtracers were conducted in the sub-arctic, glacierized Tarfala (21.7 km2) catchment in northern Sweden. Isotopic hydrograph separations revealed that even though storm runoff was dominated by pre-event water the event water (i.e. rainfall) contributions to streamflow increased throughout the summer season as glacial snow cover decreased. This suggests that glaciers are a major source of the rainwater fraction in streamflow. Simultaneous injections of ten unique DNA-based microtracers confirmed this hypothesis and revealed that the transit time of water traveling from the glacier surface to the stream decreased fourfold over the summer season leading to instantaneous rainwater contributions during storm events. These results highlight that integrating simultaneous tracer injections (injecting tracers at multiple places at one time) with traditional tracer methods (sampling multiple times at one place) rather than using either approach in isolation can

  15. Coupled biotic-abiotic Mn(II) oxidation pathway mediates the formation and structural evolution of biogenic Mn oxides

    NASA Astrophysics Data System (ADS)

    Learman, D. R.; Wankel, S. D.; Webb, S. M.; Martinez, N.; Madden, A. S.; Hansel, C. M.

    2011-10-01

    Manganese (Mn) oxides are among the strongest oxidants and sorbents in the environment, impacting the transport and speciation of metals, cycling of carbon, and flow of electrons within soils and sediments. The oxidation of Mn(II) to Mn(III/IV) oxides has been primarily attributed to biological processes, due in part to the faster rates of bacterial Mn(II) oxidation compared to observed mineral-induced and other abiotic rates. Here we explore the reactivity of biogenic Mn oxides formed by a common marine bacterium ( Roseobacter sp. AzwK-3b), which has been previously shown to oxidize Mn(II) via the production of extracellular superoxide. Oxidation of Mn(II) by superoxide results in the formation of highly reactive colloidal birnessite with hexagonal symmetry. The colloidal oxides induce the rapid oxidation of Mn(II), with dramatically accelerated rates in the presence of organics, presumably due to mineral surface-catalyzed organic radical generation. Mn(II) oxidation by the colloids is further accelerated in presence of both organics and light, implicating reactive oxygen species in aiding abiotic oxidation. Indeed, the enhancement of Mn(II) oxidation is negated when the colloids are reacted with Mn(II) in the presence of superoxide dismutase, an enzyme that scavenges the reactive oxygen species (ROS) superoxide. The reactivity of the colloidal phase is short-lived due to the rapid evolution of the birnessite from hexagonal to pseudo-orthogonal symmetry. The secondary particulate triclinic birnessite phase exhibits a distinct lack of Mn(II) oxidation and subsequent Mn oxide formation. Thus, the evolution of initial reactive hexagonal birnessite to non-reactive triclinic birnessite imposes the need for continuous production of new colloidal hexagonal particles for Mn(II) oxidation to be sustained, illustrating an intimate dependency of enzymatic and mineral-based reactions in Mn(II) oxidation. Further, the coupled enzymatic and mineral-induced pathways are linked

  16. Analysis of gene evolution and metabolic pathways using the Candida Gene Order Browser

    PubMed Central

    2010-01-01

    Background Candida species are the most common cause of opportunistic fungal infection worldwide. Recent sequencing efforts have provided a wealth of Candida genomic data. We have developed the Candida Gene Order Browser (CGOB), an online tool that aids comparative syntenic analyses of Candida species. CGOB incorporates all available Candida clade genome sequences including two Candida albicans isolates (SC5314 and WO-1) and 8 closely related species (Candida dubliniensis, Candida tropicalis, Candida parapsilosis, Lodderomyces elongisporus, Debaryomyces hansenii, Pichia stipitis, Candida guilliermondii and Candida lusitaniae). Saccharomyces cerevisiae is also included as a reference genome. Results CGOB assignments of homology were manually curated based on sequence similarity and synteny. In total CGOB includes 65617 genes arranged into 13625 homology columns. We have also generated improved Candida gene sets by merging/removing partial genes in each genome. Interrogation of CGOB revealed that the majority of tandemly duplicated genes are under strong purifying selection in all Candida species. We identified clusters of adjacent genes involved in the same metabolic pathways (such as catabolism of biotin, galactose and N-acetyl glucosamine) and we showed that some clusters are species or lineage-specific. We also identified one example of intron gain in C. albicans. Conclusions Our analysis provides an important resource that is now available for the Candida community. CGOB is available at http://cgob.ucd.ie. PMID:20459735

  17. The Utility of Geometric Morphometrics to Elucidate Pathways of Cichlid Fish Evolution

    PubMed Central

    Kerschbaumer, Michaela; Sturmbauer, Christian

    2011-01-01

    Fishes of the family Cichlidae are famous for their spectacular species flocks and therefore constitute a model system for the study of the pathways of adaptive radiation. Their radiation is connected to trophic specialization, manifested in dentition, head morphology, and body shape. Geometric morphometric methods have been established as efficient tools to quantify such differences in overall body shape or in particular morphological structures and meanwhile found wide application in evolutionary biology. As a common feature, these approaches define and analyze coordinates of anatomical landmarks, rather than traditional counts or measurements. Geometric morphometric methods have several merits compared to traditional morphometrics, particularly for the distinction and analysis of closely related entities. Cichlid evolutionary research benefits from the efficiency of data acquisition, the manifold opportunities of analyses, and the potential to visualize shape changes of those landmark-based methods. This paper briefly introduces to the concepts and methods of geometric morphometrics and presents a selection of publications where those techniques have been successfully applied to various aspects of cichlid fish diversification. PMID:21716723

  18. Determination of pigments in vegetables.

    PubMed

    Schoefs, Benoît

    2004-10-29

    Plant pigments are responsible for the shining color of plant tissues. They are also found in animal tissues and, eventually in transformed food products as additives. These pigments have an important impact on the commercial value of products, because the colors establish the first contact with the consumer. In addition plant pigments may have an influence on the health of the consumers. Pigments are labile: they can be easily altered, and even destroyed. Analytical processes have been developed to determine pigment composition. The aim of this paper is to provide a brief overview of these methods.

  19. Terahertz Analysis of Quinacridone Pigments

    NASA Astrophysics Data System (ADS)

    Squires, A. D.; Kelly, M.; Lewis, R. A.

    2017-03-01

    We present terahertz spectroscopy and analysis of two commercially available quinacridone pigments in the 0.5-4.5 THz range. Our results show a clear distinction between quinacridone red and magenta pigments. We reveal four definite absorptions in the terahertz regime common to both pigments, but offset between the pigments by ˜0.2 THz. The lowest-energy line in each pigment is observed to increase in frequency by ˜0.1 THz as the temperature is reduced from 300 to 12 K.

  20. Development of Betta splendens embryos and larvae reveals variation in pigmentation patterns.

    PubMed

    Carey, Alexis N; Lyvers, Benjamin H; Ferrill, Rachel N; Johnson, Rachel L; Dumaine, Anne Marie; Sly, Belinda J

    2016-06-01

    Vertebrate pigmentation provides an ideal system for studying the intersections between evolution, genetics, and developmental biology. Teleost fish, with their accessible developmental stages and intense and diverse colours produced by chromatophores, are an ideal group for study. We set out to test whether Betta splendens is a good model organism for studying the evolution and development of diverse pigmentation. Our results demonstrate that B. splendens can be bred to produce large numbers of offspring with easily visualized pigment cells. Depending on the colour of the parents, there was variation in larval pigmentation patterns both within and between breeding events. In juveniles the developing adult pigmentation patterns showed even greater variation. These results suggest that B. splendens has great potential as a model organism for pigmentation studies.

  1. The evolution of phototransduction from an ancestral cyclic nucleotide gated pathway

    PubMed Central

    Plachetzki, David C.; Fong, Caitlin R.; Oakley, Todd H.

    2010-01-01

    The evolutionary histories of complex traits are complicated because such traits are comprised of multiple integrated and interacting components, which may have different individual histories. Phylogenetic studies of complex trait evolution often do not take this into account, instead focusing only on the history of whole, integrated traits; for example, mapping eyes as simply present or absent through history. Using the biochemistry of animal vision as a model, we demonstrate how investigating the individual components of complex systems can aid in elucidating both the origins and diversification of such systems. Opsin-based phototransduction underlies all visual phenotypes in animals, using complex protein cascades that translate light information into changes in cyclic nucleotide gated (CNG) or canonical transient receptor potential (TRPC) ion-channel activity. Here we show that CNG ion channels play a role in cnidarian phototransduction. Transcripts of a CNG ion channel co-localize with opsin in specific cell types of the eyeless cnidarian Hydra magnipapillata. Further, the CNG inhibitor cis-diltiazem ablates a stereotypical photoresponse in the hydra. Our findings in the Cnidaria, the only non-bilaterian lineage to possess functional opsins, allow us to trace the history of CNG-based photosensitivity to the very origin of animal phototransduction. Our general analytical approach, based on explicit phylogenetic analysis of individual components, contrasts the deep evolutionary history of CNG-based phototransduction, today used in vertebrate vision, with the more recent assembly of TRPC-based systems that are common to protostome (e.g. fly and mollusc) vision. PMID:20219739

  2. The roles of microphthalmia-associated transcription factor and pigmentation in melanoma.

    PubMed

    Hsiao, Jennifer J; Fisher, David E

    2014-12-01

    MITF and pigmentation play important roles in both normal melanocyte and transformed melanoma cell biology. MITF is regulated by many pathways and it also regulates many targets, some of which are still being discovered and functionally validated. MITF is involved in a wide range of processes in melanocytes, including pigment synthesis and lineage survival. Pigmentation itself plays an important role as the interface between genetic and environmental factors that contribute to melanoma.

  3. Animal pigment bilirubin discovered in plants.

    PubMed

    Pirone, Cary; Quirke, J Martin E; Priestap, Horacio A; Lee, David W

    2009-03-04

    The bile pigment bilirubin-IXalpha is the degradative product of heme, distributed among mammals and some other vertebrates. It can be recognized as the pigment responsible for the yellow color of jaundice and healing bruises. In this paper we present the first example of the isolation of bilirubin in plants. The compound was isolated from the brilliant orange-colored arils of Strelitzia nicolai, the white bird of paradise tree, and characterized by HPLC-ESMS, UV-visible, (1)H NMR, and (13)C NMR spectroscopy, as well as comparison with an authentic standard. This discovery indicates that plant cyclic tetrapyrroles may undergo degradation by a previously unknown pathway. Preliminary analyses of related plants, including S. reginae, the bird of paradise, also revealed bilirubin in the arils and flowers, indicating that the occurrence of bilirubin is not limited to a single species or tissue type.

  4. Kinetics of thermal activation of an ultraviolet cone pigment.

    PubMed

    Mooney, Victoria; Sekharan, Sivakumar; Liu, Jian; Guo, Ying; Batista, Victor S; Yan, Elsa C Y

    2015-01-14

    Visual pigments can be thermally activated via isomerization of the retinyl chromophore and hydrolysis of the Schiff base (SB) through which the retinyl chromophore is bound to the opsin protein. Here, we present the first combined experimental and theoretical study of the thermal activation of a Siberian hamster ultraviolet (SHUV) pigment. We measured the rates of thermal isomerization and hydrolysis in the SHUV pigment and bovine rhodopsin. We found that these rates were significantly faster in the UV pigment than in rhodopsin due to the difference in the structural and electrostatic effects surrounding the unprotonated Schiff base (USB) retinyl chromophore in the UV pigment. Theoretical (DFT-QM/MM) calculations of the cis-trans thermal isomerization revealed a barrier of ∼23 kcal/mol for the USB retinyl chromophore in SHUV compared to ∼40 kcal/mol for protonated Schiff base (PSB) chromophore in rhodopsin. The lower barrier for thermal isomerization in the SHUV pigment is attributed to the (i) lessening of the steric restraints near the β-ionone ring and SB ends of the chromophore, (ii) displacement of the transmembrane helix 6 (TM6) away from the binding pocket toward TM5 due to absence of the salt bridge between the USB and the protonated E113 residue, and (iii) change in orientation of the hydrogen-bonding networks (HBNs) in the extracellular loop 2 (EII). The results in comparing thermal stability of UV cone pigment and rhodopsin provide insight into molecular evolution of vertebrate visual pigments in achieving low discrete dark noise and high photosensitivity in rod pigments for dim-light vision.

  5. Raman Spectroscopy of Microbial Pigments

    PubMed Central

    Edwards, Howell G. M.; Oren, Aharon

    2014-01-01

    Raman spectroscopy is a rapid nondestructive technique providing spectroscopic and structural information on both organic and inorganic molecular compounds. Extensive applications for the method in the characterization of pigments have been found. Due to the high sensitivity of Raman spectroscopy for the detection of chlorophylls, carotenoids, scytonemin, and a range of other pigments found in the microbial world, it is an excellent technique to monitor the presence of such pigments, both in pure cultures and in environmental samples. Miniaturized portable handheld instruments are available; these instruments can be used to detect pigments in microbiological samples of different types and origins under field conditions. PMID:24682303

  6. LOCALIZED PIGMENTED VILLONODULAR SYNOVITIS: CASE REPORT.

    PubMed

    Carvalho Godoy, Fabiola Andrea de; Faustino, Carlos Alberto Cury; Meneses, Cláudio Santos; Nishi, Sergio Tadao; Góes, César Eduardo Giancoli; Canto, Abaeté Leite do

    2011-01-01

    This case concerned a female patient with a complaint of pain in the anterior region of her left knee during and after sports activities, followed by joint blockage three months ago. From imaging examinations, simple radiography of the knee was normal and magnetic resonance showed a solid expansive mass, possibly corresponding to soft-tissue chondroma or focal nodular synovitis. Arthroscopic resection of the lesion was performed, and the diagnosis of diffuse giant cell tumor resembling localized pigmented villonodular synovitis (PVNS) was made from the result of the anatomopathological examination. The patient presented good clinical evolution, with disappearance of symptoms and return to physical activities.

  7. LOCALIZED PIGMENTED VILLONODULAR SYNOVITIS: CASE REPORT

    PubMed Central

    Carvalho Godoy, Fabiola Andrea de; Faustino, Carlos Alberto Cury; Meneses, Cláudio Santos; Nishi, Sergio Tadao; Góes, César Eduardo Giancoli; Canto, Abaeté Leite do

    2015-01-01

    This case concerned a female patient with a complaint of pain in the anterior region of her left knee during and after sports activities, followed by joint blockage three months ago. From imaging examinations, simple radiography of the knee was normal and magnetic resonance showed a solid expansive mass, possibly corresponding to soft-tissue chondroma or focal nodular synovitis. Arthroscopic resection of the lesion was performed, and the diagnosis of diffuse giant cell tumor resembling localized pigmented villonodular synovitis (PVNS) was made from the result of the anatomopathological examination. The patient presented good clinical evolution, with disappearance of symptoms and return to physical activities. PMID:27027040

  8. Blue stragglers and X -ray binaries in open clusters: An observational study of alternative pathways in stellar evolution

    NASA Astrophysics Data System (ADS)

    Gosnell, Natalie Marie

    Membership studies of evolved open clusters reveal many alternative pathway stellar products whose evolution cannot be explained using single-star evolutionary models. These stars are neither rare nor anomalous, and in fact are a common occurrence in cluster populations. The goal of this thesis is to investigate the origin and evolutionary pathways of such stars through the careful study of X-ray binaries in NGC 6819 and white dwarf (WD) companions of mass transfer-formed blue straggler stars (BSSs) in NGC 188. I present the first X-ray study of the intermediate-age open cluster NGC 6819, using observations from XMM-Newton. This study of NGC 6819 is part of a systematic survey to investigate the relationship between the number of X-ray sources and cluster dynamics in the regime of massive open clusters. Of the 12 X-ray sources within the half-light radius of NGC 6819, four sources challenge single-star evolutionary models, including a candidate quiescent low-mass X-ray binary. Next, I present the first results from a Hubble Space Telescope (HST) far-ultraviolet (FUV) campaign to search for WD companions of BSSs as indicators of mass transfer formation. I find direct observational detections of young (< 250 Myr), hot WD companions in three BSS binaries. Their presence in a well-studied cluster environment allows for unparalleled constraints on the pre-mass transfer system. I outline potential formation timelines for these three BSSs, which all formed through recent mass transfer. Finally, I use HST photometry of the complete NGC 188 BSS population to place limits on the mass transfer BSS formation frequency. Comparison of the observations with models for BSS FUV emission reveals seven WD companions with temperatures greater than 11,000 K. The location of the young BSSs on an optical color-magnitude diagram suggests that using single-star evolutionary models to age luminous BSSs may be problematic. Considering other formation scenarios, the total mass transfer

  9. Evolution of fracture and fault-controlled fluid pathways in carbonates of the Albanides fold-thrust belt

    USGS Publications Warehouse

    Graham, Wall B.R.; Girbacea, R.; Mesonjesi, A.; Aydin, A.

    2006-01-01

    The process of fracture and fault formation in carbonates of the Albanides fold-thrust belt has been systematically documented using hierarchical development of structural elements from hand sample, outcrop, and geologic-map scales. The function of fractures and faults in fluid migration was elucidated using calcite cement and bitumen in these structures as a paleoflow indicator. Two prefolding pressure-solution and vein assemblages were identified: an overburden assemblage and a remote tectonic stress assemblage. Sheared layer-parallel pressure-solution surfaces of the overburden assemblage define mechanical layers. Shearing of mechanical layers associated with folding resulted in the formation of a series of folding assemblage fractures at different orientations, depending on the slip direction of individual mechanical layers. Prefolding- and folding-related fracture assemblages together formed fragmentation zones in mechanical layers and are the sites of incipient fault localization. Further deformation along these sites was accommodated by rotation and translation of fragmented rock, which formed breccia and facilitated fault offset across multiple mechanical layers. Strike-slip faults formed by this process are organized in two sets in an apparent conjugate pattern. Calcite cement and bitumen that accumulated along fractures and faults are evidence of localized fluid flow along fault zones. By systematic identification of fractures and faults, their evolution, and their fluid and bitumen contents, along with subsurface core and well-log data, we identify northeast-southwest-trending strike-slip faults and the associated structures as dominant fluid pathways in the Albanides fold-thrust belt. Copyright ?? 2006. The American Association of Petroleum Geologists. All rights reserved.

  10. Nonphotosynthetic Pigments as Potential Biosignatures

    PubMed Central

    Cockell, Charles S.; Meadows, Victoria S.

    2015-01-01

    Abstract Previous work on possible surface reflectance biosignatures for Earth-like planets has typically focused on analogues to spectral features produced by photosynthetic organisms on Earth, such as the vegetation red edge. Although oxygenic photosynthesis, facilitated by pigments evolved to capture photons, is the dominant metabolism on our planet, pigmentation has evolved for multiple purposes to adapt organisms to their environment. We present an interdisciplinary study of the diversity and detectability of nonphotosynthetic pigments as biosignatures, which includes a description of environments that host nonphotosynthetic biologically pigmented surfaces, and a lab-based experimental analysis of the spectral and broadband color diversity of pigmented organisms on Earth. We test the utility of broadband color to distinguish between Earth-like planets with significant coverage of nonphotosynthetic pigments and those with photosynthetic or nonbiological surfaces, using both 1-D and 3-D spectral models. We demonstrate that, given sufficient surface coverage, nonphotosynthetic pigments could significantly impact the disk-averaged spectrum of a planet. However, we find that due to the possible diversity of organisms and environments, and the confounding effects of the atmosphere and clouds, determination of substantial coverage by biologically produced pigments would be difficult with broadband colors alone and would likely require spectrally resolved data. Key Words: Biosignatures—Exoplanets—Halophiles—Pigmentation—Reflectance spectroscopy—Spectral models. Astrobiology 15, 341–361. PMID:25941875

  11. Energy Conserving Coating - Pigment Research

    DTIC Science & Technology

    1991-05-01

    indicated above, changes from yellow to orange. Thermochromic CVL Mixtures Thermochromic dye mixtures were made by reacting specific leuco (colorless...2 Photochromic Pigments and Dyes ................................. 3 Thermochromic Inorganic Pigments...describing the state of the art in color changing materials, from liquid crystals to thermochromic metal complexes to photochromic spiran dyes . The re- search

  12. Nonphotosynthetic pigments as potential biosignatures.

    PubMed

    Schwieterman, Edward W; Cockell, Charles S; Meadows, Victoria S

    2015-05-01

    Previous work on possible surface reflectance biosignatures for Earth-like planets has typically focused on analogues to spectral features produced by photosynthetic organisms on Earth, such as the vegetation red edge. Although oxygenic photosynthesis, facilitated by pigments evolved to capture photons, is the dominant metabolism on our planet, pigmentation has evolved for multiple purposes to adapt organisms to their environment. We present an interdisciplinary study of the diversity and detectability of nonphotosynthetic pigments as biosignatures, which includes a description of environments that host nonphotosynthetic biologically pigmented surfaces, and a lab-based experimental analysis of the spectral and broadband color diversity of pigmented organisms on Earth. We test the utility of broadband color to distinguish between Earth-like planets with significant coverage of nonphotosynthetic pigments and those with photosynthetic or nonbiological surfaces, using both 1-D and 3-D spectral models. We demonstrate that, given sufficient surface coverage, nonphotosynthetic pigments could significantly impact the disk-averaged spectrum of a planet. However, we find that due to the possible diversity of organisms and environments, and the confounding effects of the atmosphere and clouds, determination of substantial coverage by biologically produced pigments would be difficult with broadband colors alone and would likely require spectrally resolved data.

  13. Nonphotosynthetic Pigments as Potential Biosignatures

    NASA Astrophysics Data System (ADS)

    Schwieterman, Edward W.; Cockell, Charles S.; Meadows, Victoria S.

    2015-05-01

    Previous work on possible surface reflectance biosignatures for Earth-like planets has typically focused on analogues to spectral features produced by photosynthetic organisms on Earth, such as the vegetation red edge. Although oxygenic photosynthesis, facilitated by pigments evolved to capture photons, is the dominant metabolism on our planet, pigmentation has evolved for multiple purposes to adapt organisms to their environment. We present an interdisciplinary study of the diversity and detectability of nonphotosynthetic pigments as biosignatures, which includes a description of environments that host nonphotosynthetic biologically pigmented surfaces, and a lab-based experimental analysis of the spectral and broadband color diversity of pigmented organisms on Earth. We test the utility of broadband color to distinguish between Earth-like planets with significant coverage of nonphotosynthetic pigments and those with photosynthetic or nonbiological surfaces, using both 1-D and 3-D spectral models. We demonstrate that, given sufficient surface coverage, nonphotosynthetic pigments could significantly impact the disk-averaged spectrum of a planet. However, we find that due to the possible diversity of organisms and environments, and the confounding effects of the atmosphere and clouds, determination of substantial coverage by biologically produced pigments would be difficult with broadband colors alone and would likely require spectrally resolved data.

  14. Comparative chromatography of chloroplast pigment

    NASA Technical Reports Server (NTRS)

    Grandolfo, M.; Sherma, J.; Strain, H. H.

    1969-01-01

    Methods for isolation of low concentration pigments of the cocklebur species are described. The methods entail two step chromatography so that the different sorption properties of the various pigments in varying column parameters can be utilized. Columnar and thin layer methods are compared. Many conditions influence separability of the chloroplasts.

  15. Crossing of neuronal pathways: is it a response to the occurrence of separated parts for the body (limbs, eyes, etc.) during evolution?

    PubMed

    Banihani, Saleh M

    2010-04-01

    Most sensory and motor pathways in the central nervous system cross the midline. Comparing between different neuronal pathways in different species suggest that, fibers crossing is most probably a response to the development of separated parts for the body during the process of evolution. This hypothesis proposes direct link between the occurrence of fibers crossing and the occurrence of separated parts of the body such as lateral eyes and limbs. It is supported by many observations that clearly indicate that different neuronal pathways in different species cross the midline when they carry separated information and run ipsilaterally when they carry shared information. Carrying separated information seems to create a need for functional coordination between the two halves of the nervous system which seems to be mediated by the fibers crossing. This hypothesis may alert scientists to study certain aspects of sensory and/or motor pathways in different species. It also enable the students to remember whether a pathway is uncrossed or crossed based on whether this pathway carry shared or separated information.

  16. New directions in phthalocyanine pigments

    NASA Technical Reports Server (NTRS)

    Trinh, Diep VO

    1994-01-01

    Phthalocyanines have been used as a pigment in coatings and related applications for many years. These pigments are some of the most stable organic pigments known. The phthalo blue and green pigments have been known to be ultraviolet (UV) stable and thermally stable to over 400 C. These phthalocyanines are both a semiconductor and photoconductor, exhibiting catalytic activity and photostabilization capability of polymers. Many metal free and metallic phthalocyanine derivatives have been prepared. Development of the new classes of phthalocyanine pigment could be used as coating on NASA spacecraft material such as glass to decrease the optical degradation from UV light, the outside of the space station modules for UV protection, and coating on solar cells to increase lifetime and efficiency.

  17. Bees' subtle colour preferences: how bees respond to small changes in pigment concentration

    NASA Astrophysics Data System (ADS)

    Papiorek, Sarah; Rohde, Katja; Lunau, Klaus

    2013-07-01

    Variability in flower colour of animal-pollinated plants is common and caused, inter alia, by inter-individual differences in pigment concentrations. If and how pollinators, especially bees, respond to these small differences in pigment concentration is not known, but it is likely that flower colour variability impacts the choice behaviour of all flower visitors that exhibit innate and learned colour preferences. In behavioural experiments, we simulated varying pigment concentrations and studied its impact on the colour choices of bumblebees and honeybees. Individual bees were trained to artificial flowers having a specific concentration of a pigment, i.e. Acridine Orange or Aniline Blue, and then given the simultaneous choice between three test colours including the training colour, one colour of lower and one colour of higher pigment concentration. For each pigment, two set-ups were provided, covering the range of low to middle and the range of middle to high pigment concentrations. Despite the small bee-subjective perceptual contrasts between the tested stimuli and regardless of training towards medium concentrations, bees preferred neither the training stimuli nor the stimuli offering the highest pigment concentration but more often chose those stimuli offering the highest spectral purity and the highest chromatic contrast against the background. Overall, this study suggests that bees choose an intermediate pigment concentration due to its optimal conspicuousness. It is concluded that the spontaneous preferences of bees for flower colours of high spectral purity might exert selective pressure on the evolution of floral colours and of flower pigmentation.

  18. [INHERITANCE OF EPIDERMIS PIGMENTATION IN SUNFLOWER ACHENES].

    PubMed

    Gorohivets, N A; Vedmedeva, E V

    2016-01-01

    Inheritance of epidermis pigmentation in the pericarp of sunflower seeds was studied. Inheritance of pigmentation was confirmed by three alleles Ew (epidermis devoid of pigmentation), Estr (epidermal pigmentation in strips), Edg (solid pigmentation). Dominance of the lack of epidermis pigmentation over striped epidermis and striped epidermis over solid pigmentation was established. It was shown that the striped epidermis pigmentation and the presence of testa layer are controlled by two genes, expression of which is independent from each other. Yellowish hypodermis was discovered in the sample I2K2218, which is inherited monogenically dominantly.

  19. Natural pigments and sacred art

    NASA Astrophysics Data System (ADS)

    Kelekian, Lena, ,, Lady

    2010-05-01

    Since the dawn of mankind, cavemen has expressed himself through art. The earliest known cave paintings date to some 32,000 years ago and used 4 colours derived from the earth. These pigments were iron oxides and known as ochres, blacks and whites. All pigments known by the Egyptians, the Greeks, the Romans and Renaissance man were natural and it was not until the 18th century that synthetic pigments were made and widely used. Until that time all art, be it sacred or secular used only natural pigments, of which the preparation of many have been lost or rarely used because of their tedious preparation. As a geologist, a mineralogist and an artist specializing in iconography, I have been able to rediscover 89 natural pigments extracted from minerals. I use these pigments to paint my icons in the traditional Byzantine manner and also to restore old icons, bringing back their glamour and conserving them for years to come. The use of the natural pigments in its proper way also helps to preserve the traditional skills of the iconographer. In the ancient past, pigments were extremely precious. Many took an exceedingly long journey to reach the artists, and came from remote countries. Research into these pigments is the work of history, geography and anthropology. It is an interesting journey in itself to discover that the blue aquamarines came from Afghanistan, the reds from Spain, the greens Africa, and so on. In this contribution I will be describing the origins, preparation and use of some natural pigments, together with their history and provenance. Additionally, I will show how the natural pigments are used in the creation of an icon. Being a geologist iconographer, for me, is a sacrement that transforms that which is earthly, material and natural into a thing of beauty that is sacred. As bread and wine in the Eucharist, water during baptism and oil in Holy Union transmit sanctification to the beholder, natural pigments do the same when one considers an icon. The

  20. Decomposition behavior in model nickel-aluminum-chromium-X superalloys: Temporal evolution and compositional pathways on a nanoscale

    NASA Astrophysics Data System (ADS)

    Sudbrack, Chantal K.

    In model Ni-Al-Cr-X superalloys, the compositional pathways and temporal evolution of coherent gamma' (L12)-precipitation from an isothermally aged solid-solution, gamma (FCC), is investigated at: (i) 600°C, to study nucleation, growth, and coarsening; and (ii) 800°C, to study the influence of W on coarsening of a Ni-Al-Cr alloy. In the quenched Ni-5.2 Al-14.2 Cr at.% alloy, radial distribution functions establish Ni3(Al,Cr)-type short-range ordering that extends 0.6 nm and is Cr depleted. Phase separation at 600°C occurs by nucleation and growth, and the gamma'-precipitates' morphology is a mixture of isolated spheroids and spheroids in various stages of coalescence. Sub-nanometer scale compositional profiles across the gamma/gamma ' interfaces reveal: (i) transient chemical gradients of Al depletion and Cr enrichment adjacent to the precipitates; (ii) trapped Cr atoms in the growing precipitates; (iii) the interfacial width is component dependent; and (iv) increased Al solubility in the gamma '-precipitates resulting from capillarity. For a quasi-steady state, the governing power-law time dependencies during coarsening are compared to extant models and discussed in light of recent KMC simulations performed at Northwestern. Independent of the solute diffusivities, the gamma/gamma ' interfacial free-energy is determined from coarsening data to be 22 to 23 mJ m-2. In Ni-9.8 Al-8.3 Cr at.% and Ni-9.7 Al-8.5 Cr at.%, spheroidal precipitates (5--15 nm diameter) form during quenching. Initially, chemical gradients exist in the gamma'-precipitates, however, they disappear after 1 h. After 16 h aging at 800°C, the precipitates have a cuboidal morphology and align along the elastically soft <100>-type directions. Particle size distributions and spatial pair correlation functions evolve temporally, and are discussed in context of the morphological development of the gamma'-precipitates. The coarsening kinetics of the mean radius and interfacial area per unit volume obey

  1. Roles of cis- and trans-changes in the regulatory evolution of genes in the gluconeogenic pathway in yeast.

    PubMed

    Chang, Ya-Wen; Robert Liu, Fu-Guo; Yu, Ning; Sung, Huang-Mo; Yang, Peggy; Wang, Daryi; Huang, Chih-Jen; Shih, Ming-Che; Li, Wen-Hsiung

    2008-09-01

    The yeast Saccharomyces cerevisiae proliferates rapidly in glucose-containing media. As glucose is getting depleted, yeast cells enter the transition from fermentative to nonfermentative metabolism, known as the diauxic shift, which is associated with major changes in gene expression. To understand the expression evolution of genes involved in the diauxic shift and in nonfermentative metabolism within species, a laboratory strain (BY), a wild strain (RM), and a clinical isolate (YJM) were used in this study. Our data showed that the RM strain enters into the diauxic shift approximately 1 h earlier than the BY strain with an earlier, higher induction of many key transcription factors (TFs) involved in the diauxic shift. Our sequence data revealed sequence variations between BY and RM in both coding and promoter regions of the majority of these TFs. The key TF Cat8p, a zinc-finger cluster protein, is required for the expression of many genes in gluconeogenesis under nonfermentative growth, and its derepression is mediated by deactivation of Mig1p. Our kinetic study of CAT8 expression revealed that CAT8 induction corresponded to the timing of glucose depletion in both BY and RM and CAT8 was induced up to 50- to 90-folds in RM, whereas only 20- to 30-folds in BY. In order to decipher the relative importance of cis- and trans-variations in expression divergence in the gluconeogenic pathway during the diauxic shift, we studied the expression levels of MIG1, CAT8, and their downstream target genes in the cocultures and in the hybrid diploids of BY-RM, BY-YJM, and RM-YJM and in strains with swapped promoters. Our data showed that the differences between BY and RM in the expression of MIG1, the upstream regulator of CAT8, were affected mainly by changes in cis-elements, though also by changes in trans-acting factors, whereas those of CAT8 and its downstream target genes were predominantly affected by changes in trans-acting factors.

  2. Dermoscopy of pigmented skin lesions.

    PubMed

    Soyer, H P; Argenziano, G; Chimenti, S; Ruocco, V

    2001-01-01

    This paper describes the basic concepts of dermoscopy, the various dermoscopic equipments and the standard criteria for diagnosing pigmented skin lesions. In assessing dermoscopic images, both global and local features can be recognized. These features will be systematically described and illustrated in Part I of this article. First, we will focus on 8 morphologically rather distinctive global features that allow a quick, preliminary categorization of a given pigmented skin lesion. Second, we will describe various local features representing the letters of the dermoscopic alphabet. The local features permit a more detailed assessment of pigmented skin lesions.

  3. Photosynthetic pigments: perplexing persistent prevalence of 'superfluous' pigment production.

    PubMed

    Beale, Samuel I

    2008-04-22

    Phycobilins function as light-harvesting pigments in most cyanobacteria and red algae. Although green cyanobacteria of the genus Prochlorococcus express genes encoding enzymes that direct the synthesis of phycobilins, these pigments do not appear to play a role in light harvesting in Prochlorococcus. Now, it is shown that cyanophages infecting Prochlorococcus also contain genes for phycobilin-synthesizing enzymes, and these are expressed in Prochlorococcus, raising further questions as to the role of phycobilins in the host and the virus.

  4. Accumulation of yellow Monascus pigments by extractive fermentation in nonionic surfactant micelle aqueous solution.

    PubMed

    Xiong, Xu; Zhang, Xuehong; Wu, Zhenqiang; Wang, Zhilong

    2015-02-01

    Monascus species can produce various secondary metabolites of polyketide structure. In the current study, it is found that an interesting phenomenon, i.e., submerged culture of Monascus species in an aqueous solution majorly accumulated intracellular orange Monascus pigments exhibiting one peak at 470 nm with absorbance of 32 OD while extractive fermentation in a nonionic surfactant micelle aqueous solution produced extracellular and intracellular yellow Monascus pigments exhibiting one peak at 410 nm with absorbance 30 OD and 12 OD, respectively. The spectrum profiles of both intracellular and extracellular Monascus pigments were affected by surfactant loading, extractive fermentation time, and surfactant adding time. Meanwhile, the instability of orange Monascus pigments in the extracellular nonionic surfactant micelle aqueous solution was also confirmed experimentally. The mechanism behind this phenomenon is attributed to the export of intracellular yellow Monascus pigments into its broth by extractive fermentation. The transferring of intracellular yellow Monascus pigments into its broth blocks yellow Monascus pigments from further enzymatic conversion or eliminates the feedback inhibition of yellow Monascus pigments based on the biosynthetic pathway of Monascus pigments.

  5. Evolutionary Recycling of Light Signaling Components in Fleshy Fruits: New Insights on the Role of Pigments to Monitor Ripening

    PubMed Central

    Llorente, Briardo; D’Andrea, Lucio; Rodríguez-Concepción, Manuel

    2016-01-01

    Besides an essential source of energy, light provides environmental information to plants. Photosensory pathways are thought to have occurred early in plant evolution, probably at the time of the Archaeplastida ancestor, or perhaps even earlier. Manipulation of individual components of light perception and signaling networks in tomato (Solanum lycopersicum) affects the metabolism of ripening fruit at several levels. Most strikingly, recent experiments have shown that some of the molecular mechanisms originally devoted to sense and respond to environmental light cues have been re-adapted during evolution to provide plants with useful information on fruit ripening progression. In particular, the presence of chlorophylls in green fruit can strongly influence the spectral composition of the light filtered through the fruit pericarp. The concomitant changes in light quality can be perceived and transduced by phytochromes (PHYs) and PHY-interacting factors, respectively, to regulate gene expression and in turn modulate the production of carotenoids, a family of metabolites that are relevant for the final pigmentation of ripe fruits. We raise the hypothesis that the evolutionary recycling of light-signaling components to finely adjust pigmentation to the actual ripening stage of the fruit may have represented a selective advantage for primeval fleshy-fruited plants even before the extinction of dinosaurs. PMID:27014289

  6. Spectral absorption of visual pigments in stomatopod larval photoreceptors.

    PubMed

    Feller, Kathryn D; Cronin, Thomas W

    2016-03-01

    Larval stomatopod eyes appear to be much simpler versions of adult compound eyes, lacking most of the visual pigment diversity and photoreceptor specializations. Our understanding of the visual pigment diversity of larval stomatopods, however, is based on four species, which severely limits our understanding of stomatopod eye ontogeny. To investigate several poorly understood aspects of stomatopod larval eye function, we tested two hypotheses surrounding the spectral absorption of larval visual pigments. First, we examined a broad range of species to determine if stomatopod larvae generally express a single, spectral class of photoreceptor. Using microspectrophotometry (MSP) on larvae captured in the field, we found data which further support this long-standing hypothesis. MSP was also used to test whether larval species from the same geographical region express visual pigments with similar absorption spectra. Interestingly, despite occupation of the same geographical location, we did not find evidence to support our second hypothesis. Rather, there was significant variation in visual pigment absorption spectra among sympatric species. These data are important to further our understanding of larval photoreceptor spectral diversity, which is beneficial to ongoing investigations into the ontogeny, physiology, and molecular evolution of stomatopod eyes.

  7. Occurrence and formation kinetics of pyranomalvidin-procyanidin dimer pigment in Merlot red wine: impact of acidity and oxygen concentrations.

    PubMed

    Pechamat, Laurent; Zeng, Liming; Jourdes, Michael; Ghidossi, Rémy; Teissedre, Pierre-Louis

    2014-02-19

    Once released from red grape skins, anthocyanins undergo various chemical reactions leading to the formation of more stable pigments such as pyranoanthocyanin, as well as other derivatives. Among these pigments, pyranoanthocyanins linked directly to flavanol dimers have been detected and identified in aged Port wine but not in dry red wine. These pigments are very important with regard to the wine color evolution since they are involved in wine color evolution and stabilization. During this investigation, the occurrence in dry red wine of two pyranomalvidin-procyanidin dimer has been established by low and high resolution HPLC-UV-MS analysis. Moreover, the impact of acidity and oxygen levels on their formation in red wine has been estimated. After four months of evolution, the results showed that, for the same pH, the quantity of this pigment was correlated with oxygen concentrations. Moreover, for the same quantity of oxygen, the concentration of this pigment was related to the acidity level.

  8. S cones: Evolution, retinal distribution, development, and spectral sensitivity.

    PubMed

    Hunt, David M; Peichl, Leo

    2014-03-01

    S cones expressing the short wavelength-sensitive type 1 (SWS1) class of visual pigment generally form only a minority type of cone photoreceptor within the vertebrate duplex retina. Hence, their primary role is in color vision, not in high acuity vision. In mammals, S cones may be present as a constant fraction of the cones across the retina, may be restricted to certain regions of the retina or may form a gradient across the retina, and in some species, there is coexpression of SWS1 and the long wavelength-sensitive (LWS) class of pigment in many cones. During retinal development, SWS1 opsin expression generally precedes that of LWS opsin, and evidence from genetic studies indicates that the S cone pathway may be the default pathway for cone development. With the notable exception of the cartilaginous fishes, where S cones appear to be absent, they are present in representative species from all other vertebrate classes. S cone loss is not, however, uncommon; they are absent from most aquatic mammals and from some but not all nocturnal terrestrial species. The peak spectral sensitivity of S cones depends on the spectral characteristics of the pigment present. Evidence from the study of agnathans and teleost fishes indicates that the ancestral vertebrate SWS1 pigment was ultraviolet (UV) sensitive with a peak around 360 nm, but this has shifted into the violet region of the spectrum (>380 nm) on many separate occasions during vertebrate evolution. In all cases, the shift was generated by just one or a few replacements in tuning-relevant residues. Only in the avian lineage has tuning moved in the opposite direction, with the reinvention of UV-sensitive pigments.

  9. Topology of feather melanocyte progenitor niche allows complex pigment patterns to emerge.

    PubMed

    Lin, S J; Foley, J; Jiang, T X; Yeh, C Y; Wu, P; Foley, A; Yen, C M; Huang, Y C; Cheng, H C; Chen, C F; Reeder, B; Jee, S H; Widelitz, R B; Chuong, C M

    2013-06-21

    Color patterns of bird plumage affect animal behavior and speciation. Diverse patterns are present in different species and within the individual. Here, we study the cellular and molecular basis of feather pigment pattern formation. Melanocyte progenitors are distributed as a horizontal ring in the proximal follicle, sending melanocytes vertically up into the epithelial cylinder, which gradually emerges as feathers grow. Different pigment patterns form by modulating the presence, arrangement, or differentiation of melanocytes. A layer of peripheral pulp further regulates pigmentation via patterned agouti expression. Lifetime feather cyclic regeneration resets pigment patterns for physiological needs. Thus, the evolution of stem cell niche topology allows complex pigment patterning through combinatorial co-option of simple regulatory mechanisms.

  10. Multiple roles of photosynthetic and sunscreen pigments in cyanobacteria focusing on the oxidative stress.

    PubMed

    Wada, Naoki; Sakamoto, Toshio; Matsugo, Seiichi

    2013-05-30

    Cyanobacteria have two types of sunscreen pigments, scytonemin and mycosporine-like amino acids (MAAs). These secondary metabolites are thought to play multiple roles against several environmental stresses such as UV radiation and desiccation. Not only the large molar absorption coefficients of these sunscreen pigments, but also their antioxidative properties may be necessary for the protection of biological molecules against the oxidative damages induced by UV radiation. The antioxidant activity and vitrification property of these pigments are thought to be requisite for the desiccation and rehydration processes in anhydrobiotes. In this review, the multiple roles of photosynthetic pigments and sunscreen pigments on stress resistance, especially from the viewpoint of their structures, biosynthetic pathway, and in vitro studies of their antioxidant activity, will be discussed.

  11. Expression of Pigment Cell-Specific Genes in the Ontogenesis of the Sea Urchin Strongylocentrotus intermedius

    PubMed Central

    Ageenko, Natalya V.; Kiselev, Konstantin V.; Odintsova, Nelly A.

    2011-01-01

    One of the polyketide compounds, the naphthoquinone pigment echinochrome, is synthesized in sea urchin pigment cells. We analyzed polyketide synthase (pks) and sulfotransferase (sult) gene expression in embryos and larvae of the sea urchin Strongylocentrotus intermedius from various stages of development and in specific tissues of the adults. We observed the highest level of expression of the pks and sult genes at the gastrula stage. In unfertilized eggs, only trace amounts of the pks and sult transcripts were detected, whereas no transcripts of these genes were observed in spermatozoids. The addition of shikimic acid, a precursor of naphthoquinone pigments, to zygotes and embryos increased the expression of the pks and sult genes. Our findings, including the development of specific conditions to promote pigment cell differentiation of embryonic sea urchin cells in culture, represent a definitive study on the molecular signaling pathways that are involved in the biosynthesis of pigments during sea urchin development. PMID:21804858

  12. Construction of artificial pigment-protein antennae

    SciTech Connect

    Sibbald, JeNell

    1997-01-10

    Photosynthesis is a complex process which results in the conversion of solar radiation into chemical energy. This chemical energy is then used as the free energy source for all living organisms. In its basic form, photosynthesis can be described as the light-activated synthesis of carbohydrates from the simple molecules of water and carbon dioxide: 6H2O + 6 CO2 light C6H12O6 + 6 O2 This basic mechanism actually requires numerous reaction steps. The two primary steps being: the capture of light by pigment molecules in light-harvesting antenna complexes and the transfer of this captured energy to the so-called photochemical reaction center. While the preferred pathway for energy absorbed by the chromophores in the antenna complexes is transfer to the reaction center, energy can be lost to competing processes such as internal conversion or radiative decay. Therefore, the energy transfer must be rapid, typically on the order of picoseconds, to successfully compete. The focus of the present work is on the construction of light-harvesting antenna complexes incorporating modular pigment-proteins.

  13. Bile pigments in pulmonary and vascular disease.

    PubMed

    Ryter, Stefan W

    2012-01-01

    The bile pigments, biliverdin, and bilirubin, are endogenously derived substances generated during enzymatic heme degradation. These compounds have been shown to act as chemical antioxidants in vitro. Bilirubin formed in tissues circulates in the serum, prior to undergoing hepatic conjugation and biliary excretion. The excess production of bilirubin has been associated with neurotoxicity, in particular to the newborn. Nevertheless, clinical evidence suggests that mild states of hyperbilirubinemia may be beneficial in protecting against cardiovascular disease in adults. Pharmacological application of either bilirubin and/or its biological precursor biliverdin, can provide therapeutic benefit in several animal models of cardiovascular and pulmonary disease. Furthermore, biliverdin and bilirubin can confer protection against ischemia/reperfusion injury and graft rejection secondary to organ transplantation in animal models. Several possible mechanisms for these effects have been proposed, including direct antioxidant and scavenging effects, and modulation of signaling pathways regulating inflammation, apoptosis, cell proliferation, and immune responses. The practicality and therapeutic-effectiveness of bile pigment application to humans remains unclear.

  14. Genetic abnormality of the visual pathways in a "white" tiger.

    PubMed

    Guillery, R W; Kaas, J H

    1973-06-22

    "White"tigers show an inherited reduction of pigment, produced by an autosomal recessive gene. The brain of one of these tigers shows an abnormality of the visual pathways similar to abnormalities that are associated with albinism in many other mammals. There is a close relationship between the reduced pigment formation, the pathway abnormality, and strabismus.

  15. A genomic and transcriptomic approach to investigate the blue pigment phenotype in Pseudomonas fluorescens.

    PubMed

    Andreani, Nadia Andrea; Carraro, Lisa; Martino, Maria Elena; Fondi, Marco; Fasolato, Luca; Miotto, Giovanni; Magro, Massimiliano; Vianello, Fabio; Cardazzo, Barbara

    2015-11-20

    Pseudomonas fluorescens is a well-known food spoiler, able to cause serious economic losses in the food industry due to its ability to produce many extracellular, and often thermostable, compounds. The most outstanding spoilage events involving P. fluorescens were blue discoloration of several food stuffs, mainly dairy products. The bacteria involved in such high-profile cases have been identified as belonging to a clearly distinct phylogenetic cluster of the P. fluorescens group. Although the blue pigment has recently been investigated in several studies, the biosynthetic pathway leading to the pigment formation, as well as its chemical nature, remain challenging and unsolved points. In the present paper, genomic and transcriptomic data of 4 P. fluorescens strains (2 blue-pigmenting strains and 2 non-pigmenting strains) were analyzed to evaluate the presence and the expression of blue strain-specific genes. In particular, the pangenome analysis showed the presence in the blue-pigmenting strains of two copies of genes involved in the tryptophan biosynthesis pathway (including trpABCDF). The global expression profiling of blue-pigmenting strains versus non-pigmenting strains showed a general up-regulation of genes involved in iron uptake and a down-regulation of genes involved in primary metabolism. Chromogenic reaction of the blue-pigmenting bacterial cells with Kovac's reagent indicated an indole-derivative as the precursor of the blue pigment. Finally, solubility tests and MALDI-TOF mass spectrometry analysis of the isolated pigment suggested that its molecular structure is very probably a hydrophobic indigo analog.

  16. Skin Pigmentation and Pigmentary Disorders: Focus on Epidermal/Dermal Cross-Talk

    PubMed Central

    Bastonini, Emanuela; Kovacs, Daniela

    2016-01-01

    Variation in human skin and hair color is the most notable aspect of human variability and several studies in evolution, genetics and developmental biology contributed to explain the mechanisms underlying human skin pigmentation, which is responsible for differences in skin color across the world's populations. Despite skin pigmentation is primarily related to melanocytes functionality, the surrounding keratinocytes and extracellular matrix proteins and fibroblasts in the underlying dermal compartment actively contribute to cutaneous homeostasis. Many autocrine/paracrine secreted factors and cell adhesion mechanisms involving both epidermal and dermal constituents determine constitutive skin pigmentation and, whenever deregulated, the occurrence of pigmentary disorders. In particular, an increased expression of such mediators and their specific receptors frequently lead to hyperpigmentary conditions, such as in melasma and in solar lentigo, whereas a defect in their expression/release is related to hypopigmented disorders, as seen in vitiligo. All these interactions underline the relevant role of pigmentation on human evolution and biology. PMID:27274625

  17. [Radiolucent pigment gallstones (author's transl)].

    PubMed

    Wosiewitz, U; Wolpers, C; Quint, P

    1978-12-01

    Pigment gallstones may be subdivided into three different types: radiolucent and radioopaque stones in the gallbladder and radiolucent stones in the common bile duct. 35 of our patients had radiolucent pigment stones in the gallbladder; 21 of these were followed for years by repeated X-ray examination. There is only little enlargement of these stones as time passes by, however the number of these stones increases continuously. Chemical analysis could be done on such stones in 24 cases. The stones were composed of granular calcium bilirubinate and of asphalt-like products derived from abnormal bilirubin degradation. 5 patients had pigment stones in the common bile duct. These stones contained little cholesterol and exhibited a spongy microstructure characterized by small tubules with a diameter of 1 micrometer. They contained more lipids and bilirubin than the stones collected from the gallbladder and on extraction with organic solvents no asphalt-like residues could be obtained.

  18. Microprobe analysis of chlorpromazine pigmentation

    SciTech Connect

    Benning, T.L.; McCormack, K.M.; Ingram, P.; Kaplan, D.L.; Shelburne, J.D.

    1988-10-01

    We describe the histochemical, ultrastructural, and microanalytical features of a skin biopsy specimen obtained from a patient with chlorpromazine pigmentation. Golden-brown pigment granules were present in the dermis, predominantly in a perivascular arrangement. The granules stained positively with the Fontana-Masson stain for silver-reducing substances and negatively with Perl's stain for iron. Electron microscopy revealed dense inclusion bodies in dermal histiocytes, pericytes, endothelial cells, and Schwann cells, as well as lying free in the extracellular matrix. These ''chlorpromazine bodies'' were quite dense even in unosmicated, unstained ultrathin sections, indicating that the pigmentation is related, at least in part, to the inclusions. Microprobe analysis of the chlorpromazine bodies revealed a striking peak for sulfur, which strongly suggests the presence of the drug or its metabolite within these inclusions.

  19. From PIE to APPLES: The Evolution of a Survey Instrument to Explore Engineering Student Pathways. Research Brief

    ERIC Educational Resources Information Center

    Chen, Helen; Donaldson, Krista; Eris, Ozgur; Chachra, Debbie; Lichtenstein, Gary; Sheppard, Sheri; Toye, George

    2008-01-01

    The Academic Pathways Study (APS) of the NSF-funded Center for the Advancement of Engineering Education (CAEE) is a cross-university study that systematically examines how engineering students navigate their education, and how engineering skills and identity develop during their undergraduate careers. The APS has utilized a variety of methods…

  20. A phylogenetic approach to the early evolution of autotrophy: the case of the reverse TCA and the reductive acetyl-CoA pathways.

    PubMed

    Becerra, Arturo; Rivas, Mario; García-Ferris, Carlos; Lazcano, Antonio; Peretó, Juli

    2014-06-01

    In recent decades, a number of hypotheses on the autotrophic origin of life have been presented. These proposals invoke the emergence of reaction networks leading from CO or CO₂ to the organic molecules required for life. It has also been suggested that the last (universal) common ancestor (LCA or LUCA) of all extant cell lineages was a chemolitho-autotrophic thermophilic anaerobe. The antiquity of some carbon fixation pathways, the phylogenetic basal distribution of some autotrophic organisms, and the catalytic properties of iron-sulfur minerals have been advanced in support of these ideas. Here we critically examine the phylogenetic distribution and evolution of enzymes that are essential for two of the most ancient autotrophic means of metabolism: the reductive tricarboxylic acid (rTCA) cycle and the reductive acetyl-CoA pathway. Phylogenetic analysis of citryl-CoA synthetase and of citryl-CoA lyase, key enzymatic components of the rTCA cycle, and of CO dehydrogenase/acetyl-CoA synthase, a key enzyme in the reductive acetyl-CoA pathway, revealed that all three enzymes have undergone major lateral transfer events and therefore cannot be used as proof of the LCA's metabolic abilities nor as evidence of an autotrophic origin of life.

  1. Glucose metabolism in rat retinal pigment epithelium.

    PubMed

    Coffe, Víctor; Carbajal, Raymundo C; Salceda, Rocío

    2006-01-01

    The retinal pigment epithelium (RPE) is the major transport pathway for exchange of metabolites and ions between choroidal blood supply and the neural retina. To gain insight into the mechanisms controlling glucose metabolism in RPE and its possible relationship to retinopathy, we studied the influence of different glucose concentrations on glycogen and lactate levels and CO(2) production in RPE from normal and streptozotocin-treated diabetic rats. Incubation of normal RPE in the absence of glucose caused a decrease in lactate production and glycogen content. In normal RPE, increasing glucose concentrations from 5.6 mM to 30 mM caused a four-fold increase in glucose accumulation and CO(2) yield, as well as reduction in lactate and glycogen production. In RPE from diabetic rats glucose accumulation did not increase in the presence of high glucose substrate, but it showed a four- and a seven-fold increase in CO(2) production through the mitochondrial and pentose phosphate pathways, respectively. We found high glycogen levels in RPE which can be used as an energy reserve for RPE itself and/or neural retina. Findings further show that the RPE possesses a high oxidative capacity. The large increase in glucose shunting to the pentose phosphate pathway in diabetic retina exposed to high glucose suggests a need for reducing capacity, consistent with increased oxidative stress.

  2. The genetic basis of pigmentation differences within and between Drosophila species

    PubMed Central

    Massey, Jonathan; Wittkopp, Patricia J.

    2016-01-01

    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, have 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 (e.g., yellow, ebony, tan, Dat) as well as developmental regulators of these genes (e.g., 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. PMID:27282023

  3. Changes in localization and expression levels of Shroom2 and spectrin contribute to variation in amphibian egg pigmentation patterns.

    PubMed

    Lee, Chanjae; Le, Minh-Phuong; Cannatella, David; Wallingford, John B

    2009-06-01

    One contributing factor in the worldwide decline in amphibian populations is thought to be the exposure of eggs to UV light. Enrichment of pigment in the animal hemisphere of eggs laid in the sunlight defends against UV damage, but little is known about the cell biological mechanisms controlling such polarized pigment patterns. Even less is known about how such mechanisms were modified during evolution to achieve the array of amphibian egg pigment patterns. Here, we show that ectopic expression of the gamma-tubulin regulator, Shroom2, is sufficient to induce co-accumulation of pigment granules, spectrin, and dynactin in Xenopus blastomeres. Shroom2 and spectrin are enriched and co-localize specifically in the pigmented animal hemisphere of Xenopus eggs and blastulae. Moreover, Shroom2 messenger RNA (mRNA) is expressed maternally at high levels in Xenopus. In contrast to Xenopus, eggs and blastulae of Physalaemus pustulosus have very little surface pigmentation. Rather, we find that pigment is enriched in the perinuclear region of these embryos, where it co-localizes with spectrin. Moreover, maternal Shroom2 mRNA was barely detectable in Physaleamus, though zygotic levels were comparable to Xenopus. We therefore suggest that a Shroom2/spectrin/dynactin-based mechanism controls pigment localization in amphibian eggs and that variation in maternal Shroom2 mRNA levels accounts in part for variation in amphibian egg pigment patterns during evolution.

  4. Evaluating the beneficial and detrimental effects of bile pigments in early and later life.

    PubMed

    Dennery, Phyllis A

    2012-01-01

    The heme degradation pathway has been conserved throughout phylogeny and allows for the removal of a pro-oxidant and the generation of unique molecules including bile pigments with important cellular functions. The impact of bile pigments on health and disease are reviewed, as is the special circumstance of neonatal hyperbilirubinemia. In addition, the importance of promoter polymorphisms in the UDP-glucuronosyl transferase gene (UGTA1), which is key to the elimination of excess bilirubin and to the prevention of its toxicity, are discussed. Overall, the duality of bile pigments as either cytoprotective or toxic molecules is highlighted.

  5. A small number of genes underlie male pigmentation traits in Lake Malawi cichlid fishes.

    PubMed

    O'Quin, Claire T; Drilea, Alexi C; Roberts, Reade B; Kocher, Thomas D

    2012-05-01

    Pigmentation patterns are one of the most recognizable forms of phenotypic diversity and an important component of organismal fitness. While much progress has been made in understanding the genes controlling pigmentation in model systems, many questions remain about the genetic basis of pigment traits observed in nature. Lake Malawi cichlid fishes are known for their diversity of male pigmentation patterns, which have been shaped by sexual selection. To begin the process of identifying the genes underlying this diversity, we quantified the number of pigment cells on the body and fins of two species of the genus Metriaclima and their hybrids. We then used the Castle-Wright equation to estimate that differences in individual pigmentation traits between these species are controlled by one to four genes each. Different pigmentation traits are highly correlated in the F(2) , suggesting shared developmental pathways and genetic pleiotropy. Melanophore and xanthophore traits fall on opposite ends of the first principal component axis of the F(2) phenotypes, suggesting a tradeoff during the development of these two pigment cell types.

  6. The brainstem efferent acoustic chiasm in pigmented and albino rats.

    PubMed

    Reuss, Stefan; Closhen-Gabrisch, Stefanie; Closhen, Christina

    2016-02-01

    The present study examined whether structural peculiarities in the brain-efferent pathway to the organ of Corti may underlie functional differences in hearing between pigmented and albino individuals of the same mammalian species. Pigmented Brown-Norway rats and albino Wistar rats received unilateral injections of an aqueous solution of the retrograde neuronal tracer Fluorogold (FG) into the scala tympani of the cochlea to identify olivocochlear neurons (OCN) in the brainstem superior olivary complex. After five days, brains were perfusion-fixed and brainstem sections were cut and analyzed with respect to retrogradely labeled neurons. Intrinsic neurons of the lateral system were located exclusively in the ipsilateral lateral superior olive (LSO) in both groups. Shell neurons surrounding the LSO and in periolivary regions, which made up only 5-8% of all OCN, were more often contralaterally located in albino than in pigmented animals. A striking difference was observed in the laterality of neurons of the medial olivocochlear (MOC) system, which provided more than one third of all OCN. These neurons, located in the rostral periolivary region and in the ventral nucleus of the trapezoid body, were observed contralateral to 45% in pigmented and to 68% in albino animals. Our study, the first to compare the origin of the olivocochlear bundle in pigmented and albino rats, provides evidence for differences in the crossing pattern of the olivocochlear pathway. These were found predominantly in the MOC system providing the direct efferent innervation of cochlear outer hair cells. Our findings may account for the alterations in auditory perception observed in albino mammals including man.

  7. The Whole Genome Sequence of Sphingobium chlorophenolicum L-1: Insights into the Evolution of the Pentachlorophenol Degradation Pathway

    SciTech Connect

    Copley, Shelley D.; Rokicki, Joseph; Turner, Pernilla; Daligault, Hajnalka E.; Nolan, Matt; Land, Miriam L

    2012-01-01

    Sphingobium chlorophenolicum Strain L-1 can mineralize the toxic pesticide pentachlorophenol (PCP). We have sequenced the genome of S. chlorophenolicum Strain L-1. The genome consists of a primary chromosome that encodes most of the genes for core processes, a secondary chromosome that encodes primarily genes that appear to be involved in environmental adaptation, and a small plasmid. The genes responsible for degradation of PCP are found on chromosome 2. We have compared the genomes of S. chlorophenolicum Strain L-1 and Sphingobium japonicum, a closely related Sphingomonad that degrades lindane. Our analysis suggests that the genes encoding the first three enzymes in the PCP degradation pathway were acquired via two different horizontal gene transfer events, and the genes encoding the final two enzymes in the pathway were acquired from the most recent common ancestor of these two bacteria.

  8. Developmental pathways of Glossotermes oculatus (Isoptera, Serritermitidae): at the cross-roads of worker caste evolution in termites.

    PubMed

    Bourguignon, Thomas; Sobotník, Jan; Hanus, Robert; Roisin, Yves

    2009-01-01

    The onset of a specialized ("true") worker caste is a crucial step in the evolution of termite societies. Such workers, permanently excluded from wing development, repeatedly evolved from totipotent immatures, called "false" workers or pseudergates. In the family Rhinotermitidae, the presence of true workers and the level of specialization of this caste are highly variable, and key taxa illustrate transitional situations providing clues about worker evolution. Here we focused on the status of working immatures of Glossotermes oculatus, from the family Serritermitidae, now thought to represent either the sister-group of the Rhinotermitidae or a basal lineage nested within them. Contrary to previous assumptions, we show that the apterous immatures performing worker tasks in G. oculatus are the source of the single wing-budded nymphal instar preceding the alate. Consequently, they qualify as pseudergates rather than true workers. However, the sex ratio is strongly male biased in pseudergates and soldiers, which is a trait usually restricted to termites with true workers. We therefore argue that pseudergates of G. oculatus are close to a point where the species could easily shift toward the differentiation of a true worker caste, and that G. oculatus pinpoints a new possible route for the evolution of true workers from pseudergates.

  9. Evolution of a Chlorobenzene Degradative Pathway Among Bacteria in a Contaminated Groundwater Mediated by a Genomic Island in Ralstonia

    DTIC Science & Technology

    2003-01-01

    In strain JS705 were a mosaic of the etc genes, previously described for Pseudomonas sp. strain 813, and a 5 kb fragment identical to strain JS745...amplification, and deampllflcation in Pseudomonas putlda F1 of a 1 05-kilobase genetic ele- ment containing the chlorocatechol degradative genes from... Pseudomonas sp. strain 813. J Bactertol 180: 4360--4369). The unique reconstruction of forma- tion of a metabolic pathway through the activity of IS elements

  10. Clofazimine-induced Hair Pigmentation.

    PubMed

    Philip, Mariam; Samson, Joan Felicita; Simi, Puthenveedu Salahudeen

    2012-07-01

    A 45-year-old man was treated with WHO multibacillary multidrug therapy for borderline leprosy and high dose daily Clofazimine for lepra reaction. Along with the expected side effect of skin pigmentation, the patient also noticed darkening of previously grey hair. This colour persisted eight months after completing multibacillary multidrug therapy.

  11. A case of pigmented Bowen's disease*

    PubMed Central

    Vivan, Márcia Maria; Hirata, Sérgio Henrique; do Nascimento, Liliane Santos; Enokihara, Milvia Maria Simões e Silva

    2017-01-01

    Pigmented Bowen's disease is a rare subtype of Bowen's disease. Clinically it presents as a slow-growing, well-defined, hyperpigmented plaque, and should be included as a differential diagnosis of other pigmented lesions. The authors describe a challenging case of pigmented Bowen's disease with non-diagnostic dermscopy findings. PMID:28225972

  12. 21 CFR 73.352 - Paracoccus pigment.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 1 2013-04-01 2013-04-01 false Paracoccus pigment. 73.352 Section 73.352 Food and... ADDITIVES EXEMPT FROM CERTIFICATION Foods § 73.352 Paracoccus pigment. (a) Identity. (1) The color additive paracoccus pigment consists of the heat-killed, dried cells of a nonpathogenic and nontoxicogenic strain...

  13. 21 CFR 178.3725 - Pigment dispersants.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Pigment dispersants. 178.3725 Section 178.3725... Certain Adjuvants and Production Aids § 178.3725 Pigment dispersants. Subject to the provisions of this regulation, the substances listed in this section may be safely used as pigment dispersants in...

  14. 21 CFR 178.3725 - Pigment dispersants.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Pigment dispersants. 178.3725 Section 178.3725... Certain Adjuvants and Production Aids § 178.3725 Pigment dispersants. Subject to the provisions of this regulation, the substances listed in this section may be safely used as pigment dispersants in...

  15. 21 CFR 73.352 - Paracoccus pigment.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 1 2012-04-01 2012-04-01 false Paracoccus pigment. 73.352 Section 73.352 Food and... ADDITIVES EXEMPT FROM CERTIFICATION Foods § 73.352 Paracoccus pigment. (a) Identity. (1) The color additive paracoccus pigment consists of the heat-killed, dried cells of a nonpathogenic and nontoxicogenic strain...

  16. 21 CFR 178.3725 - Pigment dispersants.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Pigment dispersants. 178.3725 Section 178.3725... Certain Adjuvants and Production Aids § 178.3725 Pigment dispersants. Subject to the provisions of this regulation, the substances listed in this section may be safely used as pigment dispersants in...

  17. 21 CFR 73.352 - Paracoccus pigment.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 1 2010-04-01 2010-04-01 false Paracoccus pigment. 73.352 Section 73.352 Food and... ADDITIVES EXEMPT FROM CERTIFICATION Foods § 73.352 Paracoccus pigment. (a) Identity. (1) The color additive paracoccus pigment consists of the heat-killed, dried cells of a nonpathogenic and nontoxicogenic strain...

  18. 21 CFR 178.3725 - Pigment dispersants.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Pigment dispersants. 178.3725 Section 178.3725... § 178.3725 Pigment dispersants. Subject to the provisions of this regulation, the substances listed in this section may be safely used as pigment dispersants in food-contact materials....

  19. 21 CFR 73.352 - Paracoccus pigment.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 1 2014-04-01 2014-04-01 false Paracoccus pigment. 73.352 Section 73.352 Food and... ADDITIVES EXEMPT FROM CERTIFICATION Foods § 73.352 Paracoccus pigment. (a) Identity. (1) The color additive paracoccus pigment consists of the heat-killed, dried cells of a nonpathogenic and nontoxicogenic strain...

  20. 21 CFR 73.352 - Paracoccus pigment.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 1 2011-04-01 2011-04-01 false Paracoccus pigment. 73.352 Section 73.352 Food and... ADDITIVES EXEMPT FROM CERTIFICATION Foods § 73.352 Paracoccus pigment. (a) Identity. (1) The color additive paracoccus pigment consists of the heat-killed, dried cells of a nonpathogenic and nontoxicogenic strain...

  1. 21 CFR 178.3725 - Pigment dispersants.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Pigment dispersants. 178.3725 Section 178.3725 Food... Certain Adjuvants and Production Aids § 178.3725 Pigment dispersants. Subject to the provisions of this regulation, the substances listed in this section may be safely used as pigment dispersants in...

  2. BACILLUS PYOCYANEUS AND ITS PIGMENTS

    PubMed Central

    Jordan, Edwin O.

    1899-01-01

    The principal conclusions that seem to me justified are as follows: 1. The fluorescent pigment formed by some varieties of B. pyocyaneus is produced under conditions identical with those governing the production of the pigment by other "fluorescent bacteria." 2. The production of pyocyanin is not dependent upon the presence of either phosphate or sulfate in the culture medium. It is formed in non-proteid as well as in proteid media, but is not a necessary accompaniment of the metabolic activities of the organism (e. g. tartrate solution). 3. The power of producing pyocyanin under conditions of artificial cultivation is lost sooner than the fluorescigenic power. 4. There are greater natural and acquired differences in pyocyanigenic power than in fluorescigenic. 5. The fluorescent pigment may be oxidized slowly by the action of light and air as well as by reagents into a yellow pigment, and pyocyanin may be similarly oxidized into a black pigment. 6. A convenient separation of B. pyocyaneus into four varieties would be the following: var. α, pyocyanigenic and fluorescigenic (most common); var. β, pyocyanigenic only (rare); var. γ, fluorescigenic only (not uncommon, closely related to "B. fluorescens liquefaciens"); var. δ, non-chromogenic. 7. Except for the occasional loss of one or another function the different varieties are not so plastic as sometimes assumed, and cannot be readily converted into one another by subjection to varying conditions of life. 8. The signification and correlation of the almost countless physiological variations among the members of this group in respect to growth in gelatin, behavior to temperature, indol production, etc., remain to be determined. It is not yet clear that the variations in chromogenic power can be in any way correlated with the presence or absence of other physiological functions. PMID:19866929

  3. Building a fly eye: terminal differentiation events of the retina, corneal lens, and pigmented epithelia.

    PubMed

    Charlton-Perkins, Mark; Cook, Tiffany A

    2010-01-01

    In the past, vast differences in ocular structure, development, and physiology throughout the animal kingdom led to the widely accepted notion that eyes are polyphyletic, that is, they have independently arisen multiple times during evolution. Despite the dissimilarity between vertebrate and invertebrate eyes, it is becoming increasingly evident that the development of the eye in both groups shares more similarity at the genetic level than was previously assumed, forcing a reexamination of eye evolution. Understanding the molecular underpinnings of cell type specification during Drosophila eye development has been a focus of research for many labs over the past 25 years, and many of these findings are nicely reviewed in Chapters 1 and 4. A somewhat less explored area of research, however, considers how these cells, once specified, develop into functional ocular structures. This review aims to summarize the current knowledge related to the terminal differentiation events of the retina, corneal lens, and pigmented epithelia in the fly eye. In addition, we discuss emerging evidence that the different functional components of the fly eye share developmental pathways and functions with the vertebrate eye.

  4. Carbon monoxide and bile pigments: surprising mediators of vascular function.

    PubMed

    Durante, William

    2002-08-01

    Heme oxygenase (HO) catalyzes the degradation of heme to CO, iron, and biliverdin. Biliverdin is subsequently metabolized to bilirubin by the enzyme biliverdin reductase. Although long considered irrelevant byproducts of heme catabolism, recent studies indicate that CO and the bile pigments biliverdin and bilirubin may play an important physiological role in the circulation. The release of CO by vascular cells may modulate blood flow and blood fluidity by inhibiting vasomotor tone, smooth muscle cell proliferation, and platelet aggregation. CO may also maintain the integrity of the vessel wall by directly blocking vascular cell apoptosis and by inhibiting the release of pro-apoptotic inflammatory cytokines from the vessel wall. These effects of CO are mediated via multiple pathways, including activation of soluble guanylate cyclase, potassium channels, p38 mitogen-activated protein kinase, or inhibition of cytochrome P450. In addition, the release of bile pigments may serve to sustain vascular homeostasis by protecting vascular cells from oxidative stress and by inhibiting the adhesion and infiltration of leukocytes into the vessel wall. Induction of HO-1 gene expression and the subsequent release of CO and bile pigments are observed in numerous vascular disorders and may provide an important adaptive mechanism to preserve homeostasis at sites of vascular injury. Thus, the HO-catalyzed formation of CO and bile pigments by vascular cells may function as a critical endogenous vasoprotective system. Moreover, pharmacological or genetic approaches targeting HO-1 to the vessel wall may represent a novel therapeutic approach in treating vascular disease.

  5. Melanin: the biophysiology of oral melanocytes and physiological oral pigmentation.

    PubMed

    Feller, Liviu; Masilana, Aubrey; Khammissa, Razia A G; Altini, Mario; Jadwat, Yusuf; Lemmer, Johan

    2014-03-24

    The presence of melanocytes in the oral epithelium is a well-established fact, but their physiological functions are not well defined. Melanin provides protection from environmental stressors such as ultraviolet radiation and reactive oxygen species; and melanocytes function as stress-sensors having the capacity both to react to and to produce a variety of microenvironmental cytokines and growth factors, modulating immune, inflammatory and antibacterial responses. Melanocytes also act as neuroendocrine cells producing local neurotransmitters including acetylcholine, catecholamines and opioids, and hormones of the melanocortin system such as proopiomelanocortin, adrenocorticotropic hormone and α-melanocyte stimulating hormone, that participate in intracellular and in intercellular signalling pathways, thus contributing to tissue homeostasis.There is a wide range of normal variation in melanin pigmentation of the oral mucosa. In general, darker skinned persons more frequently have oral melanin pigmentation than light-skinned persons. Variations in oral physiological pigmentation are genetically determined unless associated with some underlying disease.In this article, we discuss some aspects of the biophysiology of oral melanocytes, of the functions of melanin, and of physiological oral pigmentation.

  6. The genetic control of aposematic black pigmentation in hemimetabolous insects: insights from Oncopeltus fasciatus

    PubMed Central

    Liu, Jin; Lemonds, Thomas R.; Popadić, Aleksandar

    2014-01-01

    SUMMARY Variations in body pigmentation, encompassing both the range of specific colors as well as the spatial arrangement of those colors, are among the most noticeable and lineage-specific insect features. However, the genetic mechanisms responsible for generating this diversity are still limited to several model species that are primarily holometabolous insects. To address this lack of knowledge, we utilize Oncopeltus fasciatus, an aposematic hemimetabolous insect, as a new model to study insect pigmentation. First, to determine the genetic regulation of black pigment production in Oncopeltus, we perform an RNAi analysis on three core genes involved in the melanin pathway, tyrosine hydroxylase (TH), dopa decarboxylase (DDC), and laccase 2 (lac2). The black pigmentation is affected in all instances, showing that the black pigments in this species are derived from the melanin pathway. The results of the DDC RNAi are particularly informative because they reveal that it is Dopamine melanin, not DOPA melanin, which is the predominant component of black pigments in Oncopeltus. Second, we test whether pigmentation follows a two-step model where the spatial pre-mapping of enzymatic activity is followed by vein-dependent transportation of melanin substances. We confirm the existence of the first step by observing that premature wings develop black pigmentation when exposed to melanin precursors. In addition, we provide evidence for the second step by showing that wing melanin patterning is disrupted when vein transportation is halted. These findings bring novel insights from a hemimetabolous species and establish a framework for subsequent studies on the mechanisms of pigment production and patterning responsible for variations in insect coloration. PMID:25124093

  7. The genetic control of aposematic black pigmentation in hemimetabolous insects: insights from Oncopeltus fasciatus.

    PubMed

    Liu, Jin; Lemonds, Thomas R; Popadić, Aleksandar

    2014-09-01

    Variations in body pigmentation, encompassing both the range of specific colors as well as the spatial arrangement of those colors, are among the most noticeable and lineage-specific insect features. However, the genetic mechanisms responsible for generating this diversity are still limited to several model species that are primarily holometabolous insects. To address this lack of knowledge, we utilize Oncopeltus fasciatus, an aposematic hemimetabolous insect, as a new model to study insect pigmentation. First, to determine the genetic regulation of black pigment production in Oncopeltus, we perform an RNAi analysis on three core genes involved in the melanin pathway, tyrosine hydroxylase (TH), dopa decarboxylase (DDC), and laccase 2 (lac2). The black pigmentation is affected in all instances, showing that the black pigments in this species are derived from the melanin pathway. The results of the DDC RNAi are particularly informative because they reveal that it is Dopamine melanin, not DOPA melanin, which is the predominant component of black pigments in Oncopeltus. Second, we test whether pigmentation follows a two-step model where the spatial pre-mapping of enzymatic activity is followed by vein-dependent transportation of melanin substances. We confirm the existence of the first step by observing that premature wings develop black pigmentation when exposed to melanin precursors. In addition, we provide evidence for the second step by showing that wing melanin patterning is disrupted when vein transportation is halted. These findings bring novel insights from a hemimetabolous species and establish a framework for subsequent studies on the mechanisms of pigment production and patterning responsible for variations in insect coloration.

  8. The Hedgehog gene family of the cnidarian, Nematostella vectensis, and implications for understanding metazoan Hedgehog pathway evolution

    PubMed Central

    Matus, David Q.; Magie, Craig; Pang, Kevin; Martindale, Mark Q; Thomsen, Gerald H.

    2008-01-01

    Hedgehog signaling is an important component of cell-cell communication during bilaterian development, and abnormal Hedgehog signaling contributes to disease and birth defects. Hedgehog genes are composed of a ligand (“hedge”) domain and an autocatalytic intein (“hog”) domain. Hedgehog (hh) ligands bind to a conserved set of receptors and activate downstream signal transduction pathways terminating with Gli/Ci transcription factors. We have identified five intein-containing genes in the anthozoan cnidarian Nematostella vectensis, two of which (NvHh1 and NvHh2) contain definitive hedgehog ligand domains, suggesting that to date, cnidarians are the earliest branching metazoan phylum to possess definitive Hh orthologs. Expression analysis of NvHh1 and NvHh2, the receptor NvPatched and a downstream transcription factor NvGli (a Gli3/Ci ortholog) indicate that these genes may have conserved roles in planar and trans-epithelial signaling during gut and germline development, while the three remaining intein-containing genes (NvHint1,2,3) are expressed in a cell-type specific manner in putative neural precursors. Metazoan intein-containing genes that lack a ligand domain have previously only been identified within nematodes. However, phylogenetic analyses suggest that these nematode inteins may be derived from an ancestral nematode true hedgehog gene, and that the non-bilaterian intein-containing genes identified here may represent an ancestral state prior to the domain swapping events that resulted in the formation of true hedgehog genes in the cnidarian-bilaterian ancestor. Genomic surveys of N. vectensis suggest that most of the components of both protostome and deuterostome Hh signaling pathways are present in anthozoans and that some appear to have been lost in ecdysozoan lineages. Cnidarians possess many bilaterian cell-cell signaling pathways (Wnt, TGFß, FGF and Hh) that appear to act in concert to pattern tissues along the oral-aboral axis of the polyp

  9. Thermodynamic and kinetic modeling of mineralogical evolution in the Soultz-sous-Forêts geothermal system: insights into the reaction pathways

    NASA Astrophysics Data System (ADS)

    Van Ngo, Viet; Lucas, Yann; Clément, Alain; Fritz, Bertrand

    2015-04-01

    The energy production from hot fractured rocks has been investigated at the Soultz-sous-Forêts EGS (Alsace, France) from nearly three decades. Three wells have been drilled up to the depth of about 5000 m in which two wells are served as the fluid production and the third as a fluid re-injection. The circulation of geothermal fluids through the fractured reservoir leads to a strong chemical nonequilibrium of the solid and aqueous phases, which potentially cause changes in porosity, permeability, and flow pathways of the geothermal reservoir. Numerous experimental and modeling studies (e.g., Dubois et al., 2000; Baldeyrou et al., 2003; Ledésert et al., 2009; Fritz et al., 2010; Ledésert et al., 2010) carried out within the framework of the Soultz-sous-Forêts system have reported that quartz, calcite and illites are formed as the major secondary phases in the main fractures. Some contributions among the above publications further indicated that calcite plays an important role in the reduction of permeability of the fractured zones and illites are considered as a characteristic product of the hydrothermal vein alteration. Therefore, it is important to predict the evolution of minerals (especially for quartz, calcite, and illites), which may potentially modify the transport properties of the geothermal reservoir (e.g., Ledésert et al., 2009; Fritz et al., 2010). Understanding the changes in mineralogy in the fractured zones is also useful to choose the reagents in order to improve the permeability of the geothermal reservoir via the chemical stimulation. The overall objectives of the current study are to (i) investigate the long-term evolution of mineralogy in the geothermal Soultz-sous-Forêts Enhanced Geothermal System (EGS), (ii) establish the relationship between different mineral groups, (iii) study the reaction pathways, and (iv) compare the thermodynamic and kinetic approaches. The numerical calculations carried out using the KINDIS numerical code were

  10. Continental variation in wing pigmentation in Calopteryx damselflies is related to the presence of heterospecifics.

    PubMed

    Hassall, Christopher

    2014-01-01

    Wing pigmentation in Calopteryx damselflies, caused by the deposition of melanin, is energetically expensive to produce and enhances predation risk. However, patterns of melanisation are used in species identification, greater pigmentation is an accurate signal of male immune function in at least some species, and there may be a role for pigment in thermoregulation. This study tested two potential hypotheses to explain the presence of, and variation in, this pigmentation based on these three potential benefits using 907 male specimens of Calopteryx maculata collected from 49 sites (34 discrete populations) across the geographical range of the species in North America: (i) pigmentation varies with the presence of the closely related species, Calopteryx aequabilis, and (ii) pigment increases at higher latitudes as would be expected if it enhances thermoregulatory capacity. No gradual latitudinal pattern was observed, as might be expected if pigmentation was involved in thermoregulation. However, strong variation was observed between populations that were sympatric or allopatric with C. aequabilis. This variation was characterised by dark wings through allopatry in the south of the range and then a step change to much lighter wings at the southern border of sympatry. Pigmentation then increased further north into the sympatric zone, finally returning to allopatry levels at the northern range margin. These patterns are qualitatively similar to variation in pigmentation in C. aequabilis, meaning that the data are consistent with what would be expected from convergent character displacement. Overall, the results corroborate recent research that has suggested sexual selection as a primary driver behind the evolution of wing pigmentation in this group.

  11. Evolution of galactoglycerolipid biosynthetic pathways--from cyanobacteria to primary plastids and from primary to secondary plastids.

    PubMed

    Petroutsos, Dimitris; Amiar, Souad; Abida, Heni; Dolch, Lina-Juana; Bastien, Olivier; Rébeillé, Fabrice; Jouhet, Juliette; Falconet, Denis; Block, Maryse A; McFadden, Geoffrey I; Bowler, Chris; Botté, Cyrille; Maréchal, Eric

    2014-04-01

    Photosynthetic membranes have a unique lipid composition that has been remarkably well conserved from cyanobacteria to chloroplasts. These membranes are characterized by a very high content in galactoglycerolipids, i.e., mono- and digalactosyldiacylglycerol (MGDG and DGDG, respectively). Galactoglycerolipids make up the bulk of the lipid matrix in which photosynthetic complexes are embedded. They are also known to fulfill specific functions, such as stabilizing photosystems, being a source of polyunsaturated fatty acids for various purposes and, in some eukaryotes, being exported to other subcellular compartments. The conservation of MGDG and DGDG suggests that selection pressures might have conserved the enzymes involved in their biosynthesis, but this does not appear to be the case. Important evolutionary transitions comprise primary endosymbiosis (from a symbiotic cyanobacterium to a primary chloroplast) and secondary endosymbiosis (from a symbiotic unicellular algal eukaryote to a secondary plastid). In this review, we compare biosynthetic pathways based on available molecular and biochemical data, highlighting enzymatic reactions that have been conserved and others that have diverged or been lost, as well as the emergence of parallel and alternative biosynthetic systems originating from other metabolic pathways. Questions for future research are highlighted.

  12. Early development and orientation of the acoustic funnel provides insight into the evolution of sound reception pathways in cetaceans.

    PubMed

    Yamato, Maya; Pyenson, Nicholas D

    2015-01-01

    Whales receive underwater sounds through a fundamentally different mechanism than their close terrestrial relatives. Instead of hearing through the ear canal, cetaceans hear through specialized fatty tissues leading to an evolutionarily novel feature: an acoustic funnel located anterior to the tympanic aperture. We traced the ontogenetic development of this feature in 56 fetal specimens from 10 different families of toothed (odontocete) and baleen (mysticete) whales, using X-ray computed tomography. We also charted ear ossification patterns through ontogeny to understand the impact of heterochronic developmental processes. We determined that the acoustic funnel arises from a prominent V-shaped structure established early in ontogeny, formed by the malleus and the goniale. In odontocetes, this V-formation develops into a cone-shaped funnel facing anteriorly, directly into intramandibular acoustic fats, which is likely functionally linked to the anterior orientation of sound reception in echolocation. In contrast, the acoustic funnel in balaenopterids rotates laterally, later in fetal development, consistent with a lateral sound reception pathway. Balaenids and several fossil mysticetes retain a somewhat anteriorly oriented acoustic funnel in the mature condition, indicating that a lateral sound reception pathway in balaenopterids may be a recent evolutionary innovation linked to specialized feeding modes, such as lunge-feeding.

  13. Signaling pathways that regulate life and cell death: evolution of apoptosis in the context of self-defense.

    PubMed

    Muñoz-Pinedo, Cristina

    2012-01-01

    Programmed Cell Death is essential for the life cycle of many organisms. Cell death in multicellular organisms can occur as a consequence of massive damage (necrosis) or in a controlled form, through engagement of diverse biochemical programs. The best well known form of programmed cell death is apoptosis. Apoptosis occurs in animals as a consequence of a variety of stimuli including stress and social signals and it plays essential roles in morphogenesis and immune defense. The machinery of apoptosis is well conserved among animals and it is composed of caspases (the proteases which execute cell death), adapter proteins (caspase activators), Bcl-2 family proteins and Inhibitor of Apoptosis Proteins (IAPs). We will describe in this chapter the main apoptotic pathways in animals: the extrinsic (death receptor-mediated), the intrinsic/mitochondrial and the Granzyme B pathway. Other forms of non-apoptotic Programmed Cell Death which occur in animals will also be discussed. We will summarize the current knowledge about apoptotic-like and other forms of cell death in other organisms such as plants and protists.Additionally, we will discuss the hypothesis that apoptosis originated as part of a host defense mechanism. We will explore the similarities between the protein complexes which mediate apoptosis (apoptosomes) and complexes involved in immunity: inflammasomes. Additional functions of apoptotic proteins related to immune function will be summarized, in an effort to explore the evolutionary origins of cell death.

  14. Unraveling the thread of nature's tapestry: the genetics of diversity and convergence in animal pigmentation.

    PubMed

    Kronforst, Marcus R; Barsh, Gregory S; Kopp, Artyom; Mallet, James; Monteiro, Antónia; Mullen, Sean P; Protas, Meredith; Rosenblum, Erica B; Schneider, Christopher J; Hoekstra, Hopi E

    2012-07-01

    Animals display incredibly diverse color patterns yet little is known about the underlying genetic basis of these phenotypes. However, emerging results are reshaping our view of how the process of phenotypic evolution occurs. Here, we outline recent research from three particularly active areas of investigation: melanin pigmentation in Drosophila, wing patterning in butterflies, and pigment variation in lizards. For each system, we highlight (i) the function and evolution of color variation, (ii) various approaches that have been used to explore the genetic basis of pigment variation, and (iii) conclusions regarding the genetic basis of convergent evolution which have emerged from comparative analyses. Results from these studies indicate that natural variation in pigmentation is a particularly powerful tool to examine the molecular basis of evolution, especially with regard to convergent or parallel evolution. Comparison of these systems also reveals that the molecular basis of convergent evolution is heterogeneous, sometimes involving conserved mechanisms and sometimes not. In the near future, additional work in other emerging systems will substantially expand the scope of available comparisons.

  15. Complete genome sequence and transcriptomics analyses reveal pigment biosynthesis and regulatory mechanisms in an industrial strain, Monascus purpureus YY-1.

    PubMed

    Yang, Yue; Liu, Bin; Du, Xinjun; Li, Ping; Liang, Bin; Cheng, Xiaozhen; Du, Liangcheng; Huang, Di; Wang, Lei; Wang, Shuo

    2015-02-09

    Monascus has been used to produce natural colorants and food supplements for more than one thousand years, and approximately more than one billion people eat Monascus-fermented products during their daily life. In this study, using next-generation sequencing and optical mapping approaches, a 24.1-Mb complete genome of an industrial strain, Monascus purpureus YY-1, was obtained. This genome consists of eight chromosomes and 7,491 genes. Phylogenetic analysis at the genome level provides convincing evidence for the evolutionary position of M. purpureus. We provide the first comprehensive prediction of the biosynthetic pathway for Monascus pigment. Comparative genomic analyses show that the genome of M. purpureus is 13.6-40% smaller than those of closely related filamentous fungi and has undergone significant gene losses, most of which likely occurred during its specialized adaptation to starch-based foods. Comparative transcriptome analysis reveals that carbon starvation stress, resulting from the use of relatively low-quality carbon sources, contributes to the high yield of pigments by repressing central carbon metabolism and augmenting the acetyl-CoA pool. Our work provides important insights into the evolution of this economically important fungus and lays a foundation for future genetic manipulation and engineering of this strain.

  16. Combined use of synchrotron radiation based micro-X-ray fluorescence, micro-X-ray diffraction, micro-X-ray absorption near-edge, and micro-fourier transform infrared spectroscopies for revealing an alternative degradation pathway of the pigment cadmium yellow in a painting by Van Gogh.

    PubMed

    Van der Snickt, Geert; Janssens, Koen; Dik, Joris; De Nolf, Wout; Vanmeert, Frederik; Jaroszewicz, Jacub; Cotte, Marine; Falkenberg, Gerald; Van der Loeff, Luuk

    2012-12-04

    Over the past years a number of studies have described the instability of the pigment cadmium yellow (CdS). In a previous paper we have shown how cadmium sulfide on paintings by James Ensor oxidizes to CdSO(4)·H(2)O. The degradation process gives rise to the fading of the bright yellow color and the formation of disfiguring white crystals that are present on the paint surface in approximately 50 μm sized globular agglomerations. Here, we study cadmium yellow in the painting "Flowers in a blue vase" by Vincent van Gogh. This painting differs from the Ensor case in the fact that (a) a varnish was superimposed onto the degraded paint surface and (b) the CdS paint area is entirely covered with an opaque crust. The latter obscures the yellow color completely and thus presents a seemingly more advanced state of degradation. Analysis of a cross-sectioned and a crushed sample by combining scanning microscopic X-ray diffraction (μ-XRD), microscopic X-ray absorption near-edge spectroscopy (μ-XANES), microscopic X-ray fluorescence (μ-XRF) based chemical state mapping and scanning microscopic Fourier transform infrared (μ-FT-IR) spectrometry allowed unravelling the complex alteration pathway. Although no crystalline CdSO(4) compounds were identified on the Van Gogh paint samples, we conclude that the observed degradation was initially caused by oxidation of the original CdS pigment, similar as for the previous Ensor case. However, due to the presence of an overlying varnish containing lead-based driers and oxalate ions, secondary reactions took place. In particular, it appears that upon the photoinduced oxidation of its sulfidic counterion, the Cd(2+) ions reprecipitated at the paint/varnish interface after having formed a complex with oxalate ions that themselves are considered to be degradation products of the resin and/or oil in the varnish. The SO(4)(2-) anions, for their part, found a suitable reaction partner in Pb(2+) ions stemming from a dissolved lead

  17. Using THz Spectroscopy, Evolutionary Network Analysis Methods, and MD Simulation to Map the Evolution of Allosteric Communication Pathways in c-Type Lysozymes

    PubMed Central

    Woods, Kristina N.; Pfeffer, Juergen

    2016-01-01

    It is now widely accepted that protein function is intimately tied with the navigation of energy landscapes. In this framework, a protein sequence is not described by a distinct structure but rather by an ensemble of conformations. And it is through this ensemble that evolution is able to modify a protein’s function by altering its landscape. Hence, the evolution of protein functions involves selective pressures that adjust the sampling of the conformational states. In this work, we focus on elucidating the evolutionary pathway that shaped the function of individual proteins that make-up the mammalian c-type lysozyme subfamily. Using both experimental and computational methods, we map out specific intermolecular interactions that direct the sampling of conformational states and accordingly, also underlie shifts in the landscape that are directly connected with the formation of novel protein functions. By contrasting three representative proteins in the family we identify molecular mechanisms that are associated with the selectivity of enhanced antimicrobial properties and consequently, divergent protein function. Namely, we link the extent of localized fluctuations involving the loop separating helices A and B with shifts in the equilibrium of the ensemble of conformational states that mediate interdomain coupling and concurrently moderate substrate binding affinity. This work reveals unique insights into the molecular level mechanisms that promote the progression of interactions that connect the immune response to infection with the nutritional properties of lactation, while also providing a deeper understanding about how evolving energy landscapes may define present-day protein function. PMID:26337549

  18. Availability and Utilization of Pigments from Microalgae.

    PubMed

    Begum, Hasina; Yusoff, Fatimah Md; Banerjee, Sanjoy; Khatoon, Helena; Shariff, Mohamed

    2016-10-02

    Microalgae are the major photosynthesizers on earth and produce important pigments that include chlorophyll a, b and c, β-carotene, astaxanthin, xanthophylls, and phycobiliproteins. Presently, synthetic colorants are used in food, cosmetic, nutraceutical, and pharmaceutical industries. However, due to problems associated with the harmful effects of synthetic colorants, exploitation of microalgal pigments as a source of natural colors becomes an attractive option. There are various factors such as nutrient availability, salinity, pH, temperature, light wavelength, and light intensity that affect pigment production in microalgae. This paper reviews the availability and characteristics of microalgal pigments, factors affecting pigment production, and the application of pigments produced from microalgae. The potential of microalgal pigments as a source of natural colors is enormous as an alternative to synthetic coloring agents, which has limited applications due to regulatory practice for health reasons.

  19. Global and regional evolution of short-lived radiatively-active gases and aerosols in the Representative Concentration Pathways

    SciTech Connect

    Lamarque, J.-F.; Kyle, G. Page; Meinshausen, Malte; Riahi, Keywan; Smith, Steven J.; Van Vuuren, Detlef; Conley, Andrew; Vitt, Francis

    2011-08-05

    In this paper, we discuss the results of 2000-2100 simulations with a chemistry-climate model, focusing on the changes in atmospheric composition (troposphere and stratosphere) following the emissions associated with the Representative Concentration Pathways. We show that tropospheric ozone is projected to decrease (RCP3PD and RCP4.5) or increase (RCP8.5) between 2000 and 2100. Surface ozone in 2100 is projected to change little compared from 2000 conditions, a much-reduced impact from the projections based on the A2 scenario. Aerosols are projected to strongly decrease in the 21st century, a reflection of their projected decrease in emissions. Similarly, sulfate deposition is projected to strongly decrease. However, nitrogen deposition is projected to increase over certain regions because of the projected increase NH3 emissions.

  20. Evolution of the Sterol Biosynthetic Pathway of Pythium insidiosum and Related Oomycetes Contributes to Antifungal Drug Resistance.

    PubMed

    Lerksuthirat, Tassanee; Sangcakul, Areeporn; Lohnoo, Tassanee; Yingyong, Wanta; Rujirawat, Thidarat; Krajaejun, Theerapong

    2017-04-01

    Pythiosis is a life-threatening infectious disease caused by the oomycete Pythium insidiosum Direct exposure to Py. insidiosum zoospores can initiate infections of the eye, limb, gastrointestinal tract, or skin/subcutaneous tissue. Treatments for pythiosis have mostly relied on surgery. Antifungal drugs are generally ineffective against Py. insidiosum However, one patient with an invasive Py. insidiosum infection recovered completely following treatment with terbinafine and itraconazole. Additionally, the drug target sterol biosynthetic enzymes have been identified in the oomycete Aphanomyces euteiches It remains an open question whether Py. insidiosum is susceptible to the antifungal drugs and harbors any of the known drug target enzymes. Here, we determined the in vitro susceptibilities of terbinafine and itraconazole against 30 isolates of Py. insidiosum We also analyzed endogenous sterols and searched for genes encoding the sterol biosynthetic enzymes in the genomes of Py. insidiosum and related oomycetes. The susceptibility assay showed that the growth of each of the Py. insidiosum isolates was inhibited by the antifungal agents, but only at difficult-to-achieve concentrations, which explains the clinical resistance of the drugs in the treatment of pythiosis patients. Genome searches of Py. insidiosum and related oomycetes demonstrated that these organisms contained an incomplete set of sterol biosynthetic enzymes. Gas chromatographic mass spectrometry did not detect any sterol end products in Py. insidiosum In conclusion, Py. insidiosum possesses an incomplete sterol biosynthetic pathway. Resistance to antifungal drugs targeting enzymes in the ergosterol biosynthetic pathway in Py. insidiosum was due to modifications or losses of some of the genes encoding the drug target enzymes.

  1. Holographic films from carotenoid pigments

    NASA Astrophysics Data System (ADS)

    Toxqui-López, S.; Lecona-Sánchez, J. F.; Santacruz-Vázquez, C.; Olivares-Pérez, A.; Fuentes-Tapia, I.

    2014-02-01

    Carotenoids pigments presents in pineapple can be more than just natural dyes, which is one of the applications that now at day gives the chemical industry. In this research shown that can be used in implementing of holographic recording Films. Therefore we describe the technique how to obtain this kind of pigments trough spay drying of natural pineapple juice, which are then dissolved with water in a proportion of 0.1g to 1mL. The obtained sample is poured into glass substrates using the gravity method, after a drying of 24 hours in laboratory normal conditions the films are ready. The films are characterized by recording transmission holographic gratings (LSR 445 NL 445 nm) and measuring the diffraction efficiency holographic parameter. This recording material has good diffraction efficiency and environmental stability.

  2. Pigments, Parasites and Personalitiy: Towards a Unifying Role for Steroid Hormones?

    PubMed Central

    Kittilsen, Silje; Johansen, Ida Beitnes; Braastad, Bjarne Olai; Øverli, Øyvind

    2012-01-01

    A surging interest in the evolution of consistent trait correlations has inspired research on pigment patterns as a correlate of behavioural syndromes, or “animal personalities”. Associations between pigmentation, physiology and health status are less investigated as potentially conserved trait clusters. In the current study, lice counts performed on farmed Atlantic salmon Salmo salar naturally infected with ectoparasitic sea lice Lepeophtheirus salmonis showed that individual fish with high incidence of black melanin-based skin spots harboured fewer female sea lice carrying egg sacs, compared to less pigmented fish. There was no significant association between pigmentation and lice at other developmental stages, suggesting that host factors associated with melanin-based pigmentation may modify ectoparasite development to a larger degree than settlement. In a subsequent laboratory experiment a strong negative correlation between skin spots and post-stress cortisol levels was revealed, with less pigmented individuals showing a more pronounced cortisol response to acute stress. The observation that lice prevalence was strongly increased on a fraction of sexually mature male salmon which occurred among the farmed fish further supports a role for steroid hormones as mediators of reduced parasite resistance. The data presented here propose steroid hormones as a proximate cause for the association between melanin-based pigmentation and parasites. Possible fundamental and applied implications are discussed. PMID:22493685

  3. Cutaneous metastatic pigmented breast carcinoma.

    PubMed

    Gaitan-Gaona, Francisco; Said, Mirra C; Valdes-Rodriguez, Rodrigo

    2016-03-16

    A 66-year-old woman presented with a 3 cm black, ulcerated nodule located on the skin of the upper abdomen, just below the breast. The lesion was painful to the touch, but the patient reported no other associated symptoms and was otherwise healthy. A 4-mm punch biopsy of the affected skin was obtained and the histological diagnosis was cutaneous metastatic pigmented breast carcinoma.

  4. Visual Pigments of Goldfish Cones

    PubMed Central

    Hárosi, Ferenc I.; MacNichol, Edward F.

    1974-01-01

    Freshly isolated retinal photoreceptors of goldfish were studied microspectrophotometrically. Absolute absorptance spectra obtained from dark-adapted cone outer segments reaffirm the existence of three spectrally distinct cone types with absorption maxima at 455 ± 3,530 ± 3, and 625 ± 5 nm. These types were found often recognizable by gross cellular morphology. Side-illuminated cone outer segments were dichroic. The measured dichroic ratio for the main absorption band of each type was 2–3:1. Rapidly bleached cells revealed spectral and dichroic transitions in regions near 400–410, 435–455, and 350–360 nm. These photoproducts decay about fivefold as fast as the intermediates in frog rods. The spectral maxima of photoproducts, combined with other evidence, indicate that retinene2 is the chromophore of all three cone pigments. The average specific optical density for goldfish cone outer segments was found to be 0.0124 ± 0.0015/µm. The spectra of the blue-, and green-absorbing cones appeared to match porphyropsin standards with half-band width Δν = 4,832 ± 100 cm–1. The red-absorbing spectrum was found narrower, having Δν = 3,625 ± 100 cm–1. The results are consistent with the notion that visual pigment concentration within the outer segments is about the same for frog rods and goldfish cones, but that the blue-, and green-absorbing pigments possess molar extinctions of 30,000 liter/mol cm. The red-absorbing pigment was found to have extinction of 40,000 liter/mol cm, assuming invariance of oscillator strength among the three cone spectra. PMID:4817352

  5. Nanoscience of an ancient pigment.

    PubMed

    Johnson-McDaniel, Darrah; Barrett, Christopher A; Sharafi, Asma; Salguero, Tina T

    2013-02-06

    We describe monolayer nanosheets of calcium copper tetrasilicate, CaCuSi(4)O(10), which have strong near-IR luminescence and are amenable to solution processing methods. The facile exfoliation of bulk CaCuSi(4)O(10) into nanosheets is especially surprising in view of the long history of this material as the colored component of Egyptian blue, a well-known pigment from ancient times.

  6. PP-O and PP-V, Monascus pigment homologues, production, and phylogenetic analysis in Penicillium purpurogenum.

    PubMed

    Arai, Teppei; Kojima, Ryo; Motegi, Yoshiki; Kato, Jun; Kasumi, Takafumi; Ogihara, Jun

    2015-12-01

    The production of pigments as secondary metabolites by microbes is known to vary by species and by physiological conditions within a single strain. The fungus strain Penicillium purpurogenum IAM15392 has been found to produce violet pigment (PP-V) and orange pigment (PP-O),Monascus azaphilone pigment homologues, when grown under specific culture conditions. In this study, we analysed PP-V and PP-O production capability in seven strains of P. purpurogenum in addition to strain IAM15392 under specific culture conditions. The pigment production pattern of five strains cultivated in PP-V production medium was similar to that of strain IAM15392, and all violet pigments produced by these five strains were confirmed to be PP-V. Strains that did not produce pigment were also identified. In addition, two strains cultivated in PP-O production medium produced a violet pigment identified as PP-V. The ribosomal DNA (rDNA) internal transcribed spacer (ITS) region sequences from the eight P. purpurogenum strains were sequenced and used to construct a neighbor-joining phylogenetic tree. PP-O and PP-V production of P. purpurogenum was shown to be related to phylogenetic placement based on rDNA ITS sequence. Based on these results, two hypotheses for the alteration of pigment production of P. purpurogenum in evolution were proposed.

  7. Human pigmentation genes and their response to solar UV radiation.

    PubMed

    Sturm, R A

    1998-11-09

    Identification and characterisation of the genes involved in melanin pigment formation, together with the study of how their action is influenced by exposure to UV radiation, is providing a molecular understanding of the process of skin photoprotection through tanning. The mechanisms underlying this change in epidermal melanin involve both a transcriptional response of the pigmentation genes and post-translational control of the melanin biosynthetic pathway. UV rays are known to interact with numerous molecules within cells, and among these the photochemical reactions involving lipids and DNA are implicated in modulating melanogenesis. The combination of DNA damage, the formation of diacylglycerol, and the action of the melanocyte stimulating hormone receptor are all likely to be involved in UV-induced tanning.

  8. Production and biological activities of yellow pigments from Monascus fungi.

    PubMed

    Chen, Gong; Wu, Zhenqiang

    2016-08-01

    Monascus yellow pigments (MYPs), are azaphilone compounds and one of the three main components of total Monascus pigments (MPs). Thirty-five hydrophilic or hydrophobic MYPs have been identified, with the majority being hydrophobic. Apart from screening special Monascus strains, some advanced approaches, such as extractive and high-cell-density fermentations, have been applied for developing or producing new MYPs, especially extracellular hydrophilic MYPs. The outstanding performance of MYPs in terms of resistance to photodegradation, as well as tolerance for temperature and pH, give natural MYPs reasonable prospects, compared with the orange and red MPs, for practical use in the present and future. Meanwhile, MYPs have shown promising potential for applications in the food and pharmaceutical industries based on their described bioactivities. This review briefly summarizes the reports to date on chemical structures, biological activities, biosynthetic pathways, production technologies, and physicochemical performances of MYPs. The existing problems for MYPs are discussed and research prospects proposed.

  9. Intraspecific geographic variation in rod and cone visual pigment sensitivity of a parrot, Platycercus elegans

    PubMed Central

    Knott, Ben; Berg, Mathew L.; Ribot, Raoul F. H.; Endler, John A.; Bennett, Andrew T. D.

    2017-01-01

    Variation in wavelength sensitivity among subspecies is unknown among vertebrates. The parrot Platycercus elegans has extreme plumage variation between subspecies ranging from pale yellow to crimson which, with differences in background colour and light environment between subspecies, makes it a good candidate for the evolution of within-species differences in vision. We report differences in visual pigments between populations of P. elegans from two subspecies, providing the first known support for population and subspecies variation in visual pigments within a vertebrate species; it is also the first instance of intraspecific variation in rod sensitivity within any vertebrate species. Differences in wavelength sensitivity of rods and cones corresponded to geographic differences in plumage colour. Between study populations, visual pigments varied but not oil droplets. Adaptive functions for the visual pigment differences are untested but they could cause divergence in behaviours associated with colour as well as in dim light, and provide insights into the role of senses in divergence and speciation. PMID:28128324

  10. Intraspecific geographic variation in rod and cone visual pigment sensitivity of a parrot, Platycercus elegans.

    PubMed

    Knott, Ben; Berg, Mathew L; Ribot, Raoul F H; Endler, John A; Bennett, Andrew T D

    2017-01-27

    Variation in wavelength sensitivity among subspecies is unknown among vertebrates. The parrot Platycercus elegans has extreme plumage variation between subspecies ranging from pale yellow to crimson which, with differences in background colour and light environment between subspecies, makes it a good candidate for the evolution of within-species differences in vision. We report differences in visual pigments between populations of P. elegans from two subspecies, providing the first known support for population and subspecies variation in visual pigments within a vertebrate species; it is also the first instance of intraspecific variation in rod sensitivity within any vertebrate species. Differences in wavelength sensitivity of rods and cones corresponded to geographic differences in plumage colour. Between study populations, visual pigments varied but not oil droplets. Adaptive functions for the visual pigment differences are untested but they could cause divergence in behaviours associated with colour as well as in dim light, and provide insights into the role of senses in divergence and speciation.

  11. An approximation to short-term evolution and sediment transport pathways along the littoral of Cadiz Bay (SW Spain)

    NASA Astrophysics Data System (ADS)

    Anfuso, G.; Benavente, J.; Del Río, L.; Gracia, F. J.

    2008-11-01

    This work presents the results of a beach-monitoring program carried out in the Bay of Cadiz (SW Spain), which consists of urban, natural and nourished beaches. In the present study, 24 topographic profiles have been monthly monitored during the 1996 1998 period, in order to draw the morphodynamic behavior of this coast and the general characterization of short-term coastal trends. This way, total volumetric budgets have been calculated for each beach profile in order to group beaches in different erosive/accreting sectors. Studied beaches recorded both erosion and accretion: the greatest accretionary trends have been observed at Aguadulce, La Costilla and Rota beaches, with values ranging from 30 to 70 m3/m. The largest erosion episodes have been recorded in the southernmost end of Valdelagrana spit, with values over 50 m3/m, and in Rota and Vistahermosa, after nourishment works. Main erosion and accretion pathways have been related to the existence of natural and human structures, which blocked the longshore drift suggesting the existence of littoral cells.

  12. Sequence Evolution and Expression of the Androgen Receptor and Other Pathway-Related Genes in a Unisexual Fish, the Amazon Molly, Poecilia formosa, and Its Bisexual Ancestors

    PubMed Central

    Zhu, Fangjun; Schlupp, Ingo; Tiedemann, Ralph

    2016-01-01

    The all-female Amazon molly (Poecilia formosa) originated from a single hybridization of two bisexual ancestors, Atlantic molly (Poecilia mexicana) and sailfin molly (Poecilia latipinna). As a gynogenetic species, the Amazon molly needs to copulate with a heterospecific male, but the genetic information of the sperm-donor does not contribute to the next generation, as the sperm only acts as the trigger for the diploid eggs’ embryogenesis. Here, we study the sequence evolution and gene expression of the duplicated genes coding for androgen receptors (ars) and other pathway-related genes, i.e., the estrogen receptors (ers) and cytochrome P450, family19, subfamily A, aromatase genes (cyp19as), in the Amazon molly, in comparison to its bisexual ancestors. Mollies possess–as most other teleost fish—two copies of the ar, er, and cyp19a genes, i.e., arα/arβ, erα/erβ1, and cyp19a1 (also referred as cyp19a1a)/cyp19a2 (also referred to as cyp19a1b), respectively. Non-synonymous single nucleotide polymorphisms (SNPs) among the ancestral bisexual species were generally predicted not to alter protein function. Some derived substitutions in the P. mexicana and one in P. formosa are predicted to impact protein function. We also describe the gene expression pattern of the ars and pathway-related genes in various tissues (i.e., brain, gill, and ovary) and provide SNP markers for allele specific expression research. As a general tendency, the levels of gene expression were lowest in gill and highest in ovarian tissues, while expression levels in the brain were intermediate in most cases. Expression levels in P. formosa were conserved where expression did not differ between the two bisexual ancestors. In those cases where gene expression levels significantly differed between the bisexual species, P. formosa expression was always comparable to the higher expression level among the two ancestors. Interestingly, erβ1 was expressed neither in brain nor in gill in the analyzed

  13. Molecular function and potential evolution of the biofilm-modulating blue light-signalling pathway of Escherichia coli

    PubMed Central

    Tschowri, Natalia; Lindenberg, Sandra; Hengge, Regine

    2012-01-01

    Escherichia coli senses blue light via the BLUF-EAL protein BluF (YcgF). The degenerate EAL domain of BluF does not have cyclic-di-GMP phosphodiesterase activity, but BluF directly antagonizes the MerR-like repressor BluR (YcgE), which leads to expression of the ycgZ-ymgABC operon and activation of the Rcs system (Tschowri et al., 2009; Genes Dev 23: 522–534). While bluR, bluF and ycgZ have individual transcriptional start sites, comparative genome analysis indicates that the bluR-bluF-ycgZ-ymgAB region represents a functional unit in various enteric bacteria that is characterized by bluF alleles encoding degenerate EAL domains. Re-introducing conserved amino acids involved in phosphodiesterase activity of EAL domains did not restore enzymatic activity or c-di-GMP binding of BluF, but weakened its ability to antagonize BluR and improved a residual interaction with the BluR paralogue MlrA, which controls expression of the biofilm regulator CsgD and curli fibres. We identified the BluR binding site in the ycgZ promoter and observed that BluR also has residual affinity for the MlrA-dependent csgD promoter. Altogether, we propose that BluF evolved from a blue light-regulated PDE into a specific antagonist of a duplicate of MlrA that became BluR, which controls not only curli but various biofilm functions via the Ymg/Rcs pathway. PMID:22783906

  14. Dynamic diversity of the tryptophan pathway in chlamydiae: reductive evolution and a novel operon for tryptophan recapture

    PubMed Central

    Xie, Gary; Bonner, Carol A; Jensen, Roy A

    2002-01-01

    Background Complete genomic sequences of closely related organisms, such as the chlamydiae, afford the opportunity to assess significant strain differences against a background of many shared characteristics. The chlamydiae are ubiquitous intracellular parasites that are important pathogens of humans and other organisms. Tryptophan limitation caused by production of interferon-γ by the host and subsequent induction of indoleamine dioxygenase is a key aspect of the host-parasite interaction. It appears that the chlamydiae have learned to recognize tryptophan depletion as a signal for developmental remodeling. The consequent non-cultivable state of persistence can be increasingly equated to chronic disease conditions. Results The genes encoding enzymes of tryptophan biosynthesis were the focal point of this study. Chlamydophila psittaci was found to possess a compact operon containing PRPP synthase, kynureninase, and genes encoding all but the first step of tryptophan biosynthesis. All but one of the genes exhibited translational coupling. Other chlamydiae (Chlamydia trachomatis, C. muridarum and Chlamydophila pneumoniae) lack genes encoding PRPP synthase, kynureninase, and either lack tryptophan-pathway genes altogether or exhibit various stages of reductive loss. The origin of the genes comprising the trp operon does not seem to have been from lateral gene transfer. Conclusions The factors that accommodate the transition of different chlamydial species to the persistent (chronic) state of pathogenesis include marked differences in strategies deployed to obtain tryptophan from host resources. C. psittaci appears to have a novel mechanism for intercepting an early intermediate of tryptophan catabolism and recycling it back to tryptophan. In effect, a host-parasite metabolic mosaic has evolved for tryptophan recycling. PMID:12225590

  15. Heme oxygenase: evolution, structure, and mechanism.

    PubMed

    Wilks, Angela

    2002-08-01

    Heme oxygenase has evolved to carry out the oxidative cleavage of heme, a reaction essential in physiological processes as diverse as iron reutilization and cellular signaling in mammals, synthesis of essential light-harvesting pigments in cyanobacteria and higher plants, and the acquisition of iron by bacterial pathogens. In all of these processes, heme oxygenase has evolved a similar structural and mechanistic scaffold to function within seemingly diverse physiological pathways. The heme oxygenase reaction is catalytically distinct from that of other hemoproteins such as the cytochromes P450, peroxidases, and catalases, but shares a hemoprotein scaffold that has evolved to generate a distinct activated oxygen species. In the following review we discuss the evolution of the structural and functional properties of heme oxygenase in light of the recent crystal structures of the mammalian and bacterial enzymes.

  16. Development, regeneration, and evolution of feathers.

    PubMed

    Chen, Chih-Feng; Foley, John; Tang, Pin-Chi; Li, Ang; Jiang, Ting Xin; Wu, Ping; Widelitz, Randall B; Chuong, Cheng Ming

    2015-01-01

    The feather is a complex ectodermal organ with hierarchical branching patterns. It provides functions in endothermy, communication, and flight. Studies of feather growth, cycling, and health are of fundamental importance to avian biology and poultry science. In addition, feathers are an excellent model for morphogenesis studies because of their accessibility, and their distinct patterns can be used to assay the roles of specific molecular pathways. Here we review the progress in aspects of development, regeneration, and evolution during the past three decades. We cover the development of feather buds in chicken embryos, regenerative cycling of feather follicle stem cells, formation of barb branching patterns, emergence of intrafeather pigmentation patterns, interplay of hormones and feather growth, and the genetic identification of several feather variants. The discovery of feathered dinosaurs redefines the relationship between feathers and birds. Inspiration from biomaterials and flight research further fuels biomimetic potential of feathers as a multidisciplinary research focal point.

  17. Corrosion resistance of flaky aluminum pigment coated with cerium oxides/hydroxides in chloride and acidic electrolytes

    NASA Astrophysics Data System (ADS)

    Niroumandrad, S.; Rostami, M.; Ramezanzadeh, B.

    2015-12-01

    The objective of this study was to enhance the corrosion resistance of lamellar aluminum pigment through surface treatment by cerium oxides/hydroxides. The surface composition of the pigments was studied by energy-dispersive spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS). The corrosion resistance of the pigment was evaluated by conventional hydrogen evolution measurements in acidic solution and electrochemical impedance spectroscopy (EIS) in 3.5% NaCl solution. Results showed that the Ce-rich coating composed of Ce2O3 and CeO2 was precipitated on the pigment surface after immersion in the cerium solution. The corrosion resistance of pigment was significantly enhanced after modification with cerium layer.

  18. Phytochemistry: structure of the blue cornflower pigment.

    PubMed

    Shiono, Masaaki; Matsugaki, Naohiro; Takeda, Kosaku

    2005-08-11

    The same anthocyanin pigment makes roses red but cornflowers blue, a phenomenon that has so far not been entirely explained. Here we describe the X-ray crystal structure of the cornflower pigment, which reveals that its blue colour arises from a complex of six molecules each of anthocyanin and flavone, with one ferric iron, one magnesium and two calcium ions. We believe that this tetrametal complex may represent a previously undiscovered type of supermolecular pigment.

  19. SETUP, a program of representative laboratory simulations of Titan's atmosphere dedicated to better understand and quantify its chemical evolution pathways

    NASA Astrophysics Data System (ADS)

    Gazeau, M.; Bahrini, C.; Benilan, Y.; Jolly, A.; Landsheere, X.; Lebert, B.

    2013-12-01

    Atmospheres are enormously complex systems. Therefore, experimental simulations are a welcome tool in the researcher's toolbox since they provide an alternative source to compare with direct measurements and theoretical models. This is important for Titan, since direct measurements are limited and theoretical models often lack important parameters. The advantage of experimental simulations is that they reduce the problem to only the chemical reactions in a certain region by neglecting atmospheric dynamics. The experimental simulations of Titan's atmosphere performed in the frame of the SETUP (French acronym for Experimental and Theoretical Simulations Useful for Planetology) program are the most representative ever achieved towards Titan's condition in term of energy deposition: the coupled N2/CH4 chemistry is initiated in a flow reactor using microwave plasma discharge as well as Ly-alpha photons delivered by a continuous H2/He lamp. The vacuum pumping and measurement system limit the experiment to pressures above 1x10-3 mbar, which corresponds well to the lower thermosphere and below. The experiment is run at ambient temperature which does not correspond directly with any region, however the upper stratosphere and above is the closest match. According to pressure and temperature, SETUP best represents from the upper stratosphere up to the lower thermosphere. The ability to perform in-situ and absolute analysis is another improvement of SETUP over its predecessors: the chemical composition is probed in-situ using cavity ring-down spectroscopy (CRDS, an absolute and highly sensitive laser spectroscopic technique based upon absorption spectroscopy) allowing us to study the evolution of the resulting gas sample. We have chosen to use a difference-frequency generation technique that combines the advantages of decent sensitivity over widely tunable wavelength range in the mid-infrared region. Indeed, numerous molecular species exhibit their fundamental vibrational

  20. Non-photosynthetic pigments as potential biosignatures

    NASA Astrophysics Data System (ADS)

    Schwieterman, E. W.; Cockell, C. S.; Meadows, V. S.

    2014-03-01

    Photosynthetic organisms on Earth produce potentially detectable surface reflectance biosignatures due in part to the spectral location and strength of pigment absorption. However, life on Earth uses pigments for a multitude of purposes other than photosynthesis, including coping with extreme environments. Macroscopic environments exist on Earth where the surface reflectance is significantly altered by a nonphotosynthetic pigment, such as the case of hypersaline lakes and ponds (Oren et al. 1992). Here we explore the nature and potential detectability of non-photosynthetic pigments in disk-averaged planetary observations using a combination of laboratory measurements and archival reflectance spectra, along with simulated broadband photometry and spectra. The in vivo visible reflectance spectra of a cross section of pigmented microorganisms are presented to illustrate the spectral diversity of biologically produced pigments. Synthetic broadband colors are generated to show a significant spread in color space. A 1D radiative transfer model (Meadows & Crisp 1996; Crisp 1997) is used to approximate the spectra of scenarios where pigmented organisms are widespread on planets with Earth-like atmospheres. Broadband colors are revisited to show that colors due to surface reflectivity are not robust to the addition of scattering and absorption effects from the atmosphere. We consider a èbest case' plausible scenario for the detection of nonphotosynthetic pigments by using the Virtual Planetary Laboratory's 3D spectral Earth model (Robinson et al. 2011) to explore the detectability of the surface biosignature produced by pigmented halophiles that are widespread on an Earth-analog planet.

  1. Retinoid requirements for recovery of sensitivity after visual-pigment bleaching in isolated photoreceptors.

    PubMed Central

    Jones, G J; Crouch, R K; Wiggert, B; Cornwall, M C; Chader, G J

    1989-01-01

    After visual-pigment bleaching, single isolated rod photoreceptors of Ambystoma tigrinum recover their sensitivity to light when supplied with 11-cis-retinal from liposomes or with 11-cis-retinal bound to interphotoreceptor retinoid-binding protein. Bleached rods do not recover sensitivity, or do so only very slowly, after exposure to 11-cis-retinol. The latter retinoid is "toxic" in that rods actually lose sensitivity in its presence. In contrast, bleached isolated cone cells recover sensitivity when either retinoid is supplied. It is suggested that the major pathway for rhodopsin regeneration during dark adaptation in the intact eye is transport of 11-cis-retinal from the pigment epithelium to the retina. The results also suggest that there may be separate pathways for visual-pigment regeneration in rods and cones during dark adaptation. PMID:2594788

  2. Melanin pigmented solar absorbing surfaces

    SciTech Connect

    Gallas, J.M.; Eisner, M.

    1980-01-01

    Selectivity enhancement is shown to result for melanin, a black biopolymer pigment, for sufficiently low sample density. The effect is proposed to follow from a consideration of the evanescent waves associated with the total internal reflection phenomenon. A relationship is discussed among powder density, pH and the paramagnetic properties of melanin; this relationship is shown to be consistent with, and offer support to an amino-acid side group proposed earlier as part of the melanin structure. A brief discussion is also presented on the optical properties of melanin and the relative importance of quinhydrone, a change transfer complex believed to exist in the polymeric structure of melanin.

  3. alpha-ketoglutaric semialdehyde dehydrogenase isozymes involved in metabolic pathways of D-glucarate, D-galactarate, and hydroxy-L-proline. Molecular and metabolic convergent evolution.

    PubMed

    Watanabe, Seiya; Yamada, Masaki; Ohtsu, Iwao; Makino, Keisuke

    2007-03-02

    bacterial evolutional stage convergently. Furthermore, even the same pathway such as l-arabinose and d-glucarate/d-galactarate metabolism also evolved by the independent involvement of KGSADH.

  4. Structural evolution and tissue-specific expression of tetrapod-specific second isoform of secretory pathway Ca{sup 2+}-ATPase

    SciTech Connect

    Pestov, Nikolay B.; Dmitriev, Ruslan I.; Kostina, Maria B.; Korneenko, Tatyana V.; Shakhparonov, Mikhail I.; Modyanov, Nikolai N.

    2012-01-27

    Highlights: Black-Right-Pointing-Pointer Full-length secretory pathway Ca-ATPase (SPCA2) cloned from rat duodenum. Black-Right-Pointing-Pointer ATP2C2 gene (encoding SPCA2) exists only in genomes of Tetrapoda. Black-Right-Pointing-Pointer Rat and pig SPCA2 are expressed in intestines, lung and some secretory glands. Black-Right-Pointing-Pointer Subcellular localization of SPCA2 may depend on tissue type. Black-Right-Pointing-Pointer In rat duodenum, SPCA2 is localized in plasma membrane-associated compartments. -- Abstract: Secretory pathway Ca-ATPases are less characterized mammalian calcium pumps than plasma membrane Ca-ATPases and sarco-endoplasmic reticulum Ca-ATPases. Here we report analysis of molecular evolution, alternative splicing, tissue-specific expression and subcellular localization of the second isoform of the secretory pathway Ca-ATPase (SPCA2), the product of the ATP2C2 gene. The primary structure of SPCA2 from rat duodenum deduced from full-length transcript contains 944 amino acid residues, and exhibits 65% sequence identity with known SPCA1. The rat SPCA2 sequence is also highly homologous to putative human protein KIAA0703, however, the latter seems to have an aberrant N-terminus originating from intron 2. The tissue-specificity of SPCA2 expression is different from ubiquitous SPCA1. Rat SPCA2 transcripts were detected predominantly in gastrointestinal tract, lung, trachea, lactating mammary gland, skin and preputial gland. In the newborn pig, the expression profile is very similar with one remarkable exception: porcine bulbourethral gland gave the strongest signal. Upon overexpression in cultured cells, SPCA2 shows an intracellular distribution with remarkable enrichment in Golgi. However, in vivo SPCA2 may be localized in compartments that differ among various tissues: it is intracellular in epidermis, but enriched in plasma membranes of the intestinal epithelium. Analysis of SPCA2 sequences from various vertebrate species argue that ATP2C2

  5. Evolution of high-level ethambutol-resistant tuberculosis through interacting mutations in decaprenylphosphoryl-β-D-arabinose biosynthetic and utilization pathway genes.

    PubMed

    Safi, Hassan; Lingaraju, Subramanya; Amin, Anita; Kim, Soyeon; Jones, Marcus; Holmes, Michael; McNeil, Michael; Peterson, Scott N; Chatterjee, Delphi; Fleischmann, Robert; Alland, David

    2013-10-01

    To study the evolution of drug resistance, we genetically and biochemically characterized Mycobacterium tuberculosis strains selected in vitro for ethambutol resistance. Mutations in decaprenylphosphoryl-β-D-arabinose (DPA) biosynthetic and utilization pathway genes Rv3806c, Rv3792, embB and embC accumulated to produce a wide range of ethambutol minimal inhibitory concentrations (MICs) that depended on mutation type and number. Rv3806c mutations increased DPA synthesis, causing MICs to double from 2 to 4 μg/ml in a wild-type background and to increase from 16 to 32 μg/ml in an embB codon 306 mutant background. Synonymous mutations in Rv3792 increased the expression of downstream embC, an ethambutol target, resulting in MICs of 8 μg/ml. Multistep selection was required for high-level resistance. Mutations in embC or very high embC expression were observed at the highest resistance level. In clinical isolates, Rv3806c mutations were associated with high-level resistance and had multiplicative effects with embB mutations on MICs. Ethambutol resistance is acquired through the acquisition of mutations that interact in complex ways to produce a range of MICs, from those falling below breakpoint values to ones representing high-level resistance.

  6. Genomic clustering of cyanogenic glucoside biosynthetic genes aids their identification in Lotus japonicus and suggests the repeated evolution of this chemical defence pathway.

    PubMed

    Takos, Adam M; Knudsen, Camilla; Lai, Daniela; Kannangara, Rubini; Mikkelsen, Lisbeth; Motawia, Mohammed S; Olsen, Carl E; Sato, Shusei; Tabata, Satoshi; Jørgensen, Kirsten; Møller, Birger L; Rook, Fred

    2011-10-01

    Cyanogenic glucosides are amino acid-derived defence compounds found in a large number of vascular plants. Their hydrolysis by specific β-glucosidases following tissue damage results in the release of hydrogen cyanide. The cyanogenesis deficient1 (cyd1) mutant of Lotus japonicus carries a partial deletion of the CYP79D3 gene, which encodes a cytochrome P450 enzyme that is responsible for the first step in cyanogenic glucoside biosynthesis. The genomic region surrounding CYP79D3 contains genes encoding the CYP736A2 protein and the UDP-glycosyltransferase UGT85K3. In combination with CYP79D3, these genes encode the enzymes that constitute the entire pathway for cyanogenic glucoside biosynthesis. The biosynthetic genes for cyanogenic glucoside biosynthesis are also co-localized in cassava (Manihot esculenta) and sorghum (Sorghum bicolor), but the three gene clusters show no other similarities. Although the individual enzymes encoded by the biosynthetic genes in these three plant species are related, they are not necessarily orthologous. The independent evolution of cyanogenic glucoside biosynthesis in several higher plant lineages by the repeated recruitment of members from similar gene families, such as the CYP79s, is a likely scenario.

  7. Cuticle formation and pigmentation in beetles.

    PubMed

    Noh, Mi Young; Muthukrishnan, Subbaratnam; Kramer, Karl J; Arakane, Yasuyuki

    2016-10-01

    Adult beetles (Coleoptera) are covered primarily by a hard exoskeleton or cuticle. For example, the beetle elytron is a cuticle-rich highly modified forewing structure that shields the underlying hindwing and dorsal body surface from a variety of harmful environmental factors by acting as an armor plate. The elytron comes in a variety of colors and shapes depending on the coleopteran species. As in many other insect species, the cuticular tanning pathway begins with tyrosine and is responsible for production of a variety of melanin-like and other types of pigments. Tanning metabolism involves quinones and quinone methides, which also act as protein cross-linking agents for cuticle sclerotization. Electron microscopic analyses of rigid cuticles of the red flour beetle, Tribolium castaneum, have revealed not only numerous horizontal chitin-protein laminae but also vertically oriented columnar structures called pore canal fibers. This structural architecture together with tyrosine metabolism for cuticle tanning is likely to contribute to the rigidity and coloration of the beetle exoskeleton.

  8. Identification of microbial pigments in evaporitic matrices using Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Vítek, Petr; Jehlička, Jan; Edwards, Howell G. M.; Wierzchos, Jacek

    2010-05-01

    An evaporitic environment is considered as one of the possible habitats for life on Mars. From terrestrial geological scenarios we know that microorganisms inhabiting such an extreme environment (halophiles) are rich in protective pigments, depending on the metabolic pathways and specific adaptation to the harsh environmental conditions. Carotenoids typically occur within the cells of halophiles (bacteria, archaea as well as eukaryotic algae) in large amounts as part of their photosystem and protective adaptation to high doses of UV radiation that are typical for most recent evaporitic environments. Chlorophyll occurs in halophilic cyanobacteria together with carotenoids and possibly other pigments which are synthetised in response to the high UV radiation insolation. Here we present the results of Raman spectroscopic investigations of a) beta-carotene in experimentally prepared mixtures with halite, gypsum and epsomite; and b) cyanobacterial colonies inhabiting real halite and gypsum matrices in the Atacama Desert. Our results demonstrate the possibility of detection of beta-carotene - a typical carotenoid - in relatively low concentrations within the evaporitic powdered mixtures; the lowest concentration of carotenoid signal detected was 0,1 mg kg-1, which represents 100 ppb. Raman spectroscopic analyses of natural specimens (endolithic cyanobacteria) from the Atacama desert revealed the presence of scytonemin, an extremely efficient UV protective pigment, carotenoids of various types and chlorophyll. The detection potential as well as limitations of Raman spectroscopy as a part of a payload within future robotic space missions focused on the search for life on Mars is discussed.

  9. Ephrin-mediated restriction of ERK1/2 activity delimits the number of pigment cells in the Ciona CNS

    PubMed Central

    Haupaix, Nicolas; Abitua, Philip B.; Sirour, Cathy; Yasuo, Hitoyoshi; Levine, Michael; Hudson, Clare

    2014-01-01

    Recent evidence suggests that ascidian pigment cells are related to neural crest-derived melanocytes of vertebrates. Using live-imaging, we determine a revised cell lineage of the pigment cells in Ciona intestinalis embryos. The neural precursors undergo successive rounds of anterior-posterior (A-P) oriented cell divisions, starting at the blastula 64-cell stage. A previously unrecognized fourth A-P oriented cell division in the pigment cell lineage leads to the generation of the post-mitotic pigment cell precursors. We provide evidence that MEK/ERK signals are required for pigment cell specification until approximately 30 minutes after the final cell division has taken place. Following each of the four A-P oriented cell divisions, ERK1/2 is differentially activated in the posterior sister cells, into which the pigment cell lineage segregates. Eph/ephrin signals are critical during the third A-P oriented cell division to spatially restrict ERK1/2 activation to the posterior daughter cell. Targeted inhibition of Eph/ephrin signals results in, at neurula stages, anterior expansion of both ERK1/2 activation and a pigment cell lineage marker and subsequently, at larval stages, supernumerary pigment cells. We discuss the implications of these findings with respect to the evolution of the vertebrate neural crest. PMID:25062608

  10. Ephrin-mediated restriction of ERK1/2 activity delimits the number of pigment cells in the Ciona CNS.

    PubMed

    Haupaix, Nicolas; Abitua, Philip B; Sirour, Cathy; Yasuo, Hitoyoshi; Levine, Michael; Hudson, Clare

    2014-10-01

    Recent evidence suggests that ascidian pigment cells are related to neural crest-derived melanocytes of vertebrates. Using live-imaging, we determine a revised cell lineage of the pigment cells in Ciona intestinalis embryos. The neural precursors undergo successive rounds of anterior-posterior (A-P) oriented cell divisions, starting at the blastula 64-cell stage. A previously unrecognized fourth A-P oriented cell division in the pigment cell lineage leads to the generation of the post-mitotic pigment cell precursors. We provide evidence that MEK/ERK signals are required for pigment cell specification until approximately 30min after the final cell division has taken place. Following each of the four A-P oriented cell divisions, ERK1/2 is differentially activated in the posterior sister cells, into which the pigment cell lineage segregates. Eph/ephrin signals are critical during the third A-P oriented cell division to spatially restrict ERK1/2 activation to the posterior daughter cell. Targeted inhibition of Eph/ephrin signals results in, at neurula stages, anterior expansion of both ERK1/2 activation and a pigment cell lineage marker and subsequently, at larval stages, supernumerary pigment cells. We discuss the implications of these findings with respect to the evolution of the vertebrate neural crest.

  11. The evolution of vision.

    PubMed

    Gehring, Walter J

    2014-01-01

    In this review, the evolution of vision is retraced from its putative origins in cyanobacteria to humans. Circadian oscillatory clocks, phototropism, and phototaxis require the capability to detect light. Photosensory proteins allow us to reconstruct molecular phylogenetic trees. The evolution of animal eyes leading from an ancestral prototype to highly complex image forming eyes can be deciphered on the basis of evolutionary developmental genetic experiments and comparative genomics. As all bilaterian animals share the same master control gene, Pax6, and the same retinal and pigment cell determination genes, we conclude that the different eye-types originated monophyletically and subsequently diversified by divergent, parallel, or convergent evolution.

  12. Dermatoscopic findings of pigmented purpuric dermatosis*

    PubMed Central

    Ozkaya, Dilek Biyik; Emiroglu, Nazan; Su, Ozlem; Cengiz, Fatma Pelin; Bahali, Anil Gulsel; Yildiz, Pelin; Demirkesen, Cuyan; Onsun, Nahide

    2016-01-01

    Background Pigmented purpuric dermatosis is a chronic skin disorder of unknown aetiology characterised by symmetrical petechial and pigmented macules, often confined to the lower limbs. The aetiology of pigmented purpuric dermatosis is unknown. Dermatoscopy is a non-invasive diagnostic technique that allows the visualisation of morphological features invisible to the naked eye; it combines a method that renders the corneal layer of the skin translucent with an optical system that magnifies the image projected onto the retina. Objectives The aim of this study is to investigate the dermatoscopic findings of pigmented purpuric dermatosis. Methods This study enrolled patients diagnosed histopathologically with pigmented purpuric dermatosis who had dermatoscopic records. We reviewed the dermatoscopic images of PPD patients who attended the outpatient clinic in the Istanbul Dermatovenereology Department at the Bezmialem Vakıf University Medical Faculty. Results Dermatoscopy showed: coppery-red pigmentation (97%, n = 31) in the background, a brown network (34%, n = 11), linear vessels (22%, n = 7), round to oval red dots, globules, and patches (69%, n = 22; 75%, n = 24; 34%, n = 11; respectively), brown globules (26%, n = 8) and dots (53%, n = 17), linear brown lines (22%, n = 7), and follicular openings (13%, n = 4). Conclusion To our knowledge, this is the first study to report the dermatoscopy of pigmented purpuric dermatosis. In our opinion, dermatoscopy can be useful in the diagnosis of pigmented purpuric dermatosis. PMID:27828629

  13. Thin Layer Chromatography (TLC) of Chlorophyll Pigments.

    ERIC Educational Resources Information Center

    Foote, Jerry

    1984-01-01

    Background information, list of materials needed, procedures used, and discussion of typical results are provided for an experiment on the thin layer chromatography of chlorophyll pigments. The experiment works well in high school, since the chemicals used are the same as those used in paper chromatography of plant pigments. (JN)

  14. A survey of the trans-regulatory landscape for Drosophila melanogaster abdominal pigmentation.

    PubMed

    Rogers, William A; Grover, Sumant; Stringer, Samantha J; Parks, Jennifer; Rebeiz, Mark; Williams, Thomas M

    2014-01-15

    Trait development results from the collaboration of genes interconnected in hierarchical networks that control which genes are activated during the progression of development. While networks are understood to change over developmental time, the alterations that occur over evolutionary times are much less clear. A multitude of transcription factors and a far greater number of linkages between transcription factors and cis-regulatory elements (CREs) have been found to structure well-characterized networks, but the best understood networks control traits that are deeply conserved. Fruit fly abdominal pigmentation may represent an optimal setting to study network evolution, as this trait diversified over short evolutionary time spans. However, the current understanding of the underlying network includes a small set of transcription factor genes. Here, we greatly expand this network through an RNAi-screen of 558 transcription factors. We identified 28 genes, including previously implicated abd-A, Abd-B, bab1, bab2, dsx, exd, hth, and jing, as well as 20 novel factors with uncharacterized roles in pigmentation development. These include genes which promote pigmentation, suppress pigmentation, and some that have either male- or female-limited effects. We show that many of these transcription factors control the reciprocal expression of two key pigmentation enzymes, whereas a subset controls the expression of key factors in a female-specific circuit. We found the pupal Abd-A expression pattern was conserved between species with divergent pigmentation, indicating diversity resulted from changes to other loci. Collectively, these results reveal a greater complexity of the pigmentation network, presenting numerous opportunities to map transcription factor-CRE interactions that structure trait development and numerous candidate loci to investigate as potential targets of evolution.

  15. Bilateral pigmented villonodular synovitis of the knee

    PubMed Central

    Shah, Samir H.; Porrino, Jack A.; Green, John R.; Chew, Felix S.

    2015-01-01

    Pigmented villonodular synovitis is a disorder resulting in a villous, nodular, or villonodular proliferation of the synovium, with pigmentation related to the presence of hemosiderin. These lesions are almost exclusively benign with rare reports of malignancy. Pigmented villonodular synovitis can occur in a variety of joints and at any age but most often occurs within the knee in the young adult. Pigmented villonodular synovitis is a rare disease entity, and bilateral synchronous or metachronous involvement of a joint is even more uncommon, with few reports previously described in the literature. We present a case of pigmented villonodular synovitis involving both the right and left knee in the same patient, with radiographic imaging, magnetic resonance imaging, photograph and video intraoperative imaging, and pathologic correlation. PMID:26649121

  16. Developing fungal pigments for "painting" vascular plants.

    PubMed

    Robinson, Sara C

    2012-02-01

    The use of fungal pigments as color additives to wood as a method to increase forest revenue is a relatively new, but quickly developing field. Sugar maple (Acer saccharum) is currently the primary utilized hardwood for spalting and appears to be the best suited North American hardwood for such purposes. The combination of Trametes versicolor and Bjerkandera adusta has been identified in several instances as a strong fungal pairing for zone line production; however, Xylaria polymorpha is capable of creating zone lines without the antagonism of a secondary fungus. Few fungal pigments have been developed for reliable use; Scytalidium cuboideum is capable of producing a penetrating pink/red stain, as well as a blue pigment after extended incubation, and Chlorociboria sp. produces a blue/green pigment if grown on aspen (Populus tremuloides). Several opportunities exist for stimulation of fungal pigments including the use of copper sulfate and changes in wood pH.

  17. Melanin-Like Pigment Synthesis by Soil Bacillus weihenstephanensis Isolates from Northeastern Poland

    PubMed Central

    Drewnowska, Justyna M.; Zambrzycka, Monika; Kalska-Szostko, Beata; Fiedoruk, Krzysztof; Swiecicka, Izabela

    2015-01-01

    Although melanin is known for protecting living organisms from harmful physical and chemical factors, its synthesis is rarely observed among endospore-forming Bacillus cereus sensu lato. Here, for the first time, we reported that psychrotolerant Bacillus weihenstephanensis from Northeastern Poland can produce melanin-like pigment. We assessed physicochemical properties of the pigment and the mechanism of its synthesis in relation to B. weihenstephanensis genotypic and phenotypic characteristics. Electron paramagnetic resonance (EPR) spectroscopy displayed a stable free radical signal of the pigment from environmental isolates which are consistent with the commercial melanin. Fourier transform infrared spectroscopy (FT-IR) and physicochemical tests indicated the phenolic character of the pigment. Several biochemical tests showed that melanin-like pigment synthesis by B. weihenstephanensis was associated with laccase activity. The presence of the gene encoding laccase was confirmed by the next generation whole genome sequencing of one B. weihenstephanensis strain. Biochemical (API 20E and 50CHB tests) and genetic (Multi-locus Sequence Typing, 16S rRNA sequencing, and Pulsed-Field Gel Electrophoresis) characterization of the isolates revealed their close relation to the psychrotrophic B. weihenstephanensis DSMZ 11821 reference strain. The ability to synthesize melanin-like pigment by soil B. weihenstephanensis isolates and their psychrotrophic character seemed to be a local adaptation to a specific niche. Detailed genetic and biochemical analyses of melanin-positive environmental B. weihenstephanensis strains shed some light on the evolution and ecological adaptation of these bacteria. Moreover, our study raised new biotechnological possibilities for the use of water-soluble melanin-like pigment naturally produced by B. weihenstephanensis as an alternative to commercial non-soluble pigment. PMID:25909751

  18. Melanin-Like Pigment Synthesis by Soil Bacillus weihenstephanensis Isolates from Northeastern Poland.

    PubMed

    Drewnowska, Justyna M; Zambrzycka, Monika; Kalska-Szostko, Beata; Fiedoruk, Krzysztof; Swiecicka, Izabela

    2015-01-01

    Although melanin is known for protecting living organisms from harmful physical and chemical factors, its synthesis is rarely observed among endospore-forming Bacillus cereus sensu lato. Here, for the first time, we reported that psychrotolerant Bacillus weihenstephanensis from Northeastern Poland can produce melanin-like pigment. We assessed physicochemical properties of the pigment and the mechanism of its synthesis in relation to B. weihenstephanensis genotypic and phenotypic characteristics. Electron paramagnetic resonance (EPR) spectroscopy displayed a stable free radical signal of the pigment from environmental isolates which are consistent with the commercial melanin. Fourier transform infrared spectroscopy (FT-IR) and physicochemical tests indicated the phenolic character of the pigment. Several biochemical tests showed that melanin-like pigment synthesis by B. weihenstephanensis was associated with laccase activity. The presence of the gene encoding laccase was confirmed by the next generation whole genome sequencing of one B. weihenstephanensis strain. Biochemical (API 20E and 50CHB tests) and genetic (Multi-locus Sequence Typing, 16S rRNA sequencing, and Pulsed-Field Gel Electrophoresis) characterization of the isolates revealed their close relation to the psychrotrophic B. weihenstephanensis DSMZ 11821 reference strain. The ability to synthesize melanin-like pigment by soil B. weihenstephanensis isolates and their psychrotrophic character seemed to be a local adaptation to a specific niche. Detailed genetic and biochemical analyses of melanin-positive environmental B. weihenstephanensis strains shed some light on the evolution and ecological adaptation of these bacteria. Moreover, our study raised new biotechnological possibilities for the use of water-soluble melanin-like pigment naturally produced by B. weihenstephanensis as an alternative to commercial non-soluble pigment.

  19. Identification of Shell Colour Pigments in Marine Snails Clanculus pharaonius and C. margaritarius (Trochoidea; Gastropoda).

    PubMed

    Williams, S T; Ito, S; Wakamatsu, K; Goral, T; Edwards, N P; Wogelius, R A; Henkel, T; de Oliveira, L F C; Maia, L F; Strekopytov, S; Jeffries, T; Speiser, D I; Marsden, J T

    2016-01-01

    Colour and pattern are key traits with important roles in camouflage, warning and attraction. Ideally, in order to begin to understand the evolution and ecology of colour in nature, it is important to identify and, where possible, fully characterise pigments using biochemical methods. The phylum Mollusca includes some of the most beautiful exemplars of biological pigmentation, with the vivid colours of sea shells particularly prized by collectors and scientists alike. Biochemical studies of molluscan shell colour were fairly common in the last century, but few of these studies have been confirmed using modern methods and very few shell pigments have been fully characterised. Here, we use modern chemical and multi-modal spectroscopic techniques to identify two porphyrin pigments and eumelanin in the shell of marine snails Clanculus pharaonius and C margaritarius. The same porphyrins were also identified in coloured foot tissue of both species. We use high performance liquid chromatography (HPLC) to show definitively that these porphyrins are uroporphyrin I and uroporphyrin III. Evidence from confocal microscopy analyses shows that the distribution of porphyrin pigments corresponds to the striking pink-red of C. pharaonius shells, as well as pink-red dots and lines on the early whorls of C. margaritarius and yellow-brown colour of later whorls. Additional HPLC results suggest that eumelanin is likely responsible for black spots. We refer to the two differently coloured porphyrin pigments as trochopuniceus (pink-red) and trochoxouthos (yellow-brown) in order to distinguish between them. Trochopuniceus and trochoxouthos were not found in the shell of a third species of the same superfamily, Calliostoma zizyphinum, despite its superficially similar colouration, suggesting that this species has different shell pigments. These findings have important implications for the study of colour and pattern in molluscs specifically, but in other taxa more generally, since this

  20. Identification of Shell Colour Pigments in Marine Snails Clanculus pharaonius and C. margaritarius (Trochoidea; Gastropoda)

    PubMed Central

    Ito, S.; Wakamatsu, K.; Goral, T.; Edwards, N. P.; Wogelius, R. A.; Henkel, T.; de Oliveira, L. F. C.; Maia, L. F.; Strekopytov, S.; Speiser, D. I.; Marsden, J. T.

    2016-01-01

    Colour and pattern are key traits with important roles in camouflage, warning and attraction. Ideally, in order to begin to understand the evolution and ecology of colour in nature, it is important to identify and, where possible, fully characterise pigments using biochemical methods. The phylum Mollusca includes some of the most beautiful exemplars of biological pigmentation, with the vivid colours of sea shells particularly prized by collectors and scientists alike. Biochemical studies of molluscan shell colour were fairly common in the last century, but few of these studies have been confirmed using modern methods and very few shell pigments have been fully characterised. Here, we use modern chemical and multi-modal spectroscopic techniques to identify two porphyrin pigments and eumelanin in the shell of marine snails Clanculus pharaonius and C margaritarius. The same porphyrins were also identified in coloured foot tissue of both species. We use high performance liquid chromatography (HPLC) to show definitively that these porphyrins are uroporphyrin I and uroporphyrin III. Evidence from confocal microscopy analyses shows that the distribution of porphyrin pigments corresponds to the striking pink-red of C. pharaonius shells, as well as pink-red dots and lines on the early whorls of C. margaritarius and yellow-brown colour of later whorls. Additional HPLC results suggest that eumelanin is likely responsible for black spots. We refer to the two differently coloured porphyrin pigments as trochopuniceus (pink-red) and trochoxouthos (yellow-brown) in order to distinguish between them. Trochopuniceus and trochoxouthos were not found in the shell of a third species of the same superfamily, Calliostoma zizyphinum, despite its superficially similar colouration, suggesting that this species has different shell pigments. These findings have important implications for the study of colour and pattern in molluscs specifically, but in other taxa more generally, since this

  1. Organic pigments in plastics can cause allergic contact dermatitis.

    PubMed

    Jolanki, R; Kanerva, L; Estlander, T

    1987-01-01

    A short review on organic pigments in plastics as a cause of allergic contact dermatitis is presented. Previously, organic pigments have been reported as provoking allergic pigmented contact dermatitis when used in cosmetics. Here we present the case of a patient who developed allergic contact dermatitis from an organic pigment (Irgalite Orange F2G) in a plastic glove. This shows that organic pigments in plastics can also cause allergic contact dermatitis. The potential sensitizing capacity of organic pigments should be noted.

  2. Analysis of differentially expressed genes associated with tryptophan-dependent pigment synthesis in M. furfur by cDNA subtraction technology.

    PubMed

    Hort, W; Lang, S; Brunke, S; Mayser, P; Hube, B

    2009-05-01

    Malassezia species are associated with pityriasis versicolor (PV) and its depigmented variant pityriasis versicolor alba (PVa), widespread fungal skin infections in humans. The pathogenesis of PV and PVa remains unclear, including their clinical and histological symptoms such as hyper- and depigmentation, reduced responsiveness to ultraviolet radiation and lack of inflammatory reaction despite high fungal load. Pigments produced by M. furfur are possibly involved in the pathogenesis of PV. In vitro, M. furfur produces a wide range of pigments and fluorochromes when cultured with tryptophan as the sole nitrogen source. We have begun to analyse the molecular basis of pigment production by searching for genes associated with tryptophan-based pigment production. A suppression subtractive hybridization (SSH) protocol was used to identify genes expressed in M. furfur cells producing pigments, but not in non-induced cells. SSH was performed 3 and 5 h after onset of pigment induction. Up-regulation of genes in the pigment-producing cells was confirmed by reverse northern analysis. More than 1,500 cDNA sequences of both the indicated time points were analysed. We identified a wide variety of genes associated with metabolism and several genes with unknown function are specifically expressed during pigment production. Furthermore, a fraction of genes possibly involved in different steps of the newly discovered indolic pathway of M. furfur were expressed in pigment producing cells. These data provide the first molecular insight into pigment production of M. furfur.

  3. Structure of plant bile pigments

    SciTech Connect

    Schoenleber, R.W.

    1983-12-01

    Selective peptide cleavage has provided a general procedure for the study of the structure, including stereochemistry, of plant bile pigments. The information derived from the synthesis and spectral analysis of a series of 2,3-dihydrodioxobilins allows the determination of the trans relative stereochemistry for ring A of the ..beta../sub 1/-phycocyanobilin from C-phycocyanin as well as for ring A of phytochrome. A complete structure proof of the five phycoerythrobilins attached to the ..cap alpha.. and ..beta.. subunits of B-phycoerythrin is described. One of these tetrapyrroles is doubly-peptide linked to a single peptide chain through two thioethers at the C-3' and C-18' positions. The four remaining phycoerythrobilins are singly-linked to the protein through thioethers at the C-3' position and all possess the probable stereochemistry C-2(R), C-3(R), C-3'(R), and C-16(R).

  4. The relationship between EZH2 expression and microRNA-31 in colorectal cancer and the role in evolution of the serrated pathway

    PubMed Central

    Kurihara, Hiroyoshi; Maruyama, Reo; Ishiguro, Kazuya; Kanno, Shinichi; Yamamoto, Itaru; Ishigami, Keisuke; Mitsuhashi, Kei; Igarashi, Hisayoshi; Ito, Miki; Tanuma, Tokuma; Sukawa, Yasutaka; Okita, Kenji; Hasegawa, Tadashi; Imai, Kohzoh; Yamamoto, Hiroyuki; Shinomura, Yasuhisa; Nosho, Katsuhiko

    2016-01-01

    Polycomb group protein enhancer of zeste homolog 2 (EZH2) is a methyltransferase that correlates with the regulation of invasion and metastasis and is overexpressed in human cancers such as colorectal cancer. MicroRNA-31 (miR-31) plays an oncogenic role and is associated with BRAF mutation and poor prognosis in colorectal cancer. EZH2 is functionally considered to suppress miR-31 expression in human cancers; however, no study has reported its relationship with colon cancer. We therefore evaluated EZH2 expression using immunohistochemistry and assessed miR-31 and epigenetic alterations using 301 colorectal carcinomas and 207 premalignant lesions. Functional analysis was performed to identify the association between EZH2 and miR-31 using cancer cell lines. In the current study, negative, weak, moderate, and strong EZH2 expressions were observed in 15%, 19%, 25%, and 41% of colorectal cancers, respectively. EZH2 was inversely associated with miR-31 (P < 0.0001), independent of clinicopathological and molecular features. In a multivariate stage-stratified analysis, high EZH2 expression was related to favorable prognosis (P = 0.0022). Regarding premalignant lesions, negative EZH2 expression was frequently detected in sessile serrated adenomas/polyps (SSA/Ps) (76%; P < 0.0001) compared with hyperplastic polyps, traditional serrated adenomas, and non-serrated adenomas (25–36%). Functional analysis demonstrated that the knockdown of EZH2 increased miR-31 expression. In conclusion, an inverse association was identified between EZH2 and miR-31 in colorectal cancers. Our data also showed that upregulation of EZH2 expression may be rare in SSA/Ps. These results suggest that EZH2 suppresses miR-31 in colorectal cancer and may correlate with differentiation and evolution of serrated pathway. PMID:26871294

  5. Oxidation pathways for formic acid under low temperature hydrothermal conditions: Implications for the chemical and isotopic evolution of organics on Mars

    NASA Astrophysics Data System (ADS)

    Foustoukos, Dionysis I.; Stern, Jennifer C.

    2012-01-01

    In order to evaluate the oxidation effect of dissolved hydrogen peroxide and the catalytic role of iron oxides on the kinetics of formic acid decarboxylation, a series of flow-through hydrothermal experiments was conducted at temperatures ranging from 80 to 150 °C and pressures of 172-241 bar. δ 13C composition of residual HCOOH (aq) was also monitored to examine kinetic isotope effects associated with oxidation processes. Our results reveal that decomposition of H 2O 2(aq) in presence of magnetite follows pseudo first order kinetics, highly enhanced relative to the homogeneous H 2O 2(aq)-HCOOOH (aq)-H 2O system, which possibly reflect synthesis of hydroxyl radicals ( rad OH) through Fenton processes. The kinetic rate constants of HCOOH (aq) decarboxylation to CO 2(aq) are also elevated relative to those previously measured in H 2O 2(aq) free experiments. However, reaction kinetics are slightly slower in the case of H 2O 2(aq) aqueous solutions coexisting with magnetite than in the absence of mineral phases. This behavior is attributed to the possible formation of Fe-bearing hydroxyl formate aqueous species that could serve as stable transition states leading to a decrease in the activation entropy of formic acid decomposition. δ 13C values of residual formic acid in the homogeneous H 2O 2(aq)-HCOOH (aq)-H 2O system are consistent with previous studies. However, magnetite-bearing experiments produce a negative shift in δ 13C of residual formic acid, perhaps specific to rad OH-imposed oxidation of organic compounds. This would indicate that isotopic fractionations by this oxidation pathway are opposite to kinetic fractionation effects expected in biologically driven oxidation processes. This could have important implications for putative H 2O 2(aq)-bearing Martian subsurface environments and the evolution of organics at low-temperature hydrothermal conditions.

  6. Pigmentation in the sentinel node correlates with increased sentinel node tumor burden in melanoma patients.

    PubMed

    van Lanschot, Cornelia G F; Koljenović, Senada; Grunhagen, Dirk-Jan; Verhoef, Cornelis; van Akkooi, Alexander C J

    2014-06-01

    The prognosis of sentinel node (SN)-positive melanoma patients is predicted by a number of characteristics such as size and site of the metastases in the SN. The pathway and prognosis of strong pigmentation of melanoma metastases in the SN is unclear. The aim of this study is to evaluate the role of pigmentation and growth pattern of metastases in the SN with respect to survival. A total of 389 patients underwent an SN procedure (1997-2011). Ninety-five patients had a positive SN and material from 75 patients was available for review. The median follow-up time was 75 months (range 6-164). Pigmentation was scored from 0 to 2 using the following scale: 0=absent, 1=slight, and 2=strong. Growth pattern was scored as either eccentric (1) or infiltrative (2). SN tumor burden was measured according to the Rotterdam criteria. The primary melanoma had a median Breslow thickness of 2.90 mm (0.8-12.00 mm). Ulceration was present in 34 patients (45.3%). There was a median SN tumor burden of 0.5 mm (0.05-7.00 mm). In a total of 75 patients, 59 patients (79%) had no pigmentation, 13 patients (17%) had slight pigmentation, and three patients (4%) had strong pigmentation in the SN. Because of the small numbers, the classification was modified to either absent 59 (79%) or present 16 (21%) pigmentation, respectively. The SN tumor burden was significantly higher (P=0.031) for patients with pigmentation. Patients with pigmentation had a 5-year melanoma-specific survival (MSS) of 47% and a 10-year MSS of 33%. Patients without pigmentation had a 5-year MSS of 70% and a 10-year MSS of 59% (P=0.06). There was no difference in MSS for patients with an eccentric or an infiltrative growth pattern, nor did it correlate with other prognostic factors. Multivariate analysis for MSS showed five significant factors associated with worse prognosis: male sex (P=0.036), nodular melanoma (P=0.001), truncal site (P=0.0001), SN tumor burden more than 1.0 mm (P=0.022), and positive completion lymph node

  7. Widespread flower color convergence in Solanaceae via alternate biochemical pathways.

    PubMed

    Ng, Julienne; Smith, Stacey D

    2016-01-01

    Phenotypic convergence is rampant throughout the tree of life. While recent studies have made significant progress in ascertaining the proximate mechanisms underlying convergent phenotypes, less is known about the frequency and predictability with which convergent phenotypes arise via the same or multiple pathways at the macroevolutionary scale. We investigated the proximate causes and evolutionary patterns of red flower color in the tomato family, Solanaceae, using large-scale data mining and new sequence data to reconstruct a megaphylogeny of 1341 species. We then combined spectral and anatomical data to assess how many times red flowers have evolved, the relative contribution of different pathways to independent origins of red, and whether the underlying pathway is predicted by phylogenetic relatedness. We estimated at least 30 relatively recent origins of red flowers using anthocyanins, carotenoids, or a dual production of both pigments, with significant phylogenetic signal in the use of anthocyanins and dual production, indicating that closely related red-flowered species tend to employ the same mechanism for coloration. Our study is the first to test whether developmental pathways exhibit phylogenetic signal and implies that historical contingency strongly influences the evolution of new phenotypes.

  8. Community analysis of pigment patterns from 37 microalgae strains reveals new carotenoids and porphyrins characteristic of distinct strains and taxonomic groups

    PubMed Central

    Bérard, Jean-Baptiste; Kaas, Raymond; Pasquet, Virginie; Picot, Laurent; Cadoret, Jean-Paul

    2017-01-01

    Phytoplankton, with an estimated 30 000 to 1 000 000 species clustered in 12 phyla, presents a high taxonomic and ecophysiological diversity, reflected by the complex distribution of pigments among the different algal classes. High performance liquid chromatography is the gold standard method for qualitative and quantitative analysis of phytoplankton pigments in seawater and culture samples, but only a few pigments can be used as robust chemotaxonomic markers. A major challenge is thus to identify new ones, characteristic of a strain, species, class or taxon that cannot be currently identified on the basis of its pigment signature. Using an optimized extraction process coupled to a HPLC de-replication strategy, we examined the pigment composition of 37 microalgae strains, representative of the broad taxonomic diversity of marine and freshwater species (excluding cyanobacteria). For each species, the major pigments already described were unambiguously identified. We also observed the presence of several minor unidentified pigments in each chromatogram. The global analysis of pigment compositions revealed a total of 124 pigments, including 98 pigments or derivatives unidentified using the standards. Absorption spectra indicated that 35 corresponded to chlorophyll/porphyrin derivatives, 57 to carotenoids and six to derivatives having both spectral signatures. Sixty-one of these unidentified or new carotenoids and porphyrin derivatives were characteristic of particular strains or species, indicating their possible use as highly specific chemotaxonomic markers capable of identifying one strain out of the 37 selected. We developed a graphical analysis using Gephi software to give a clear representation of pigment communities among the various phytoplankton strains, and to reveal strain-characteristic and shared pigments. This made it possible to reconstruct the taxonomic evolution of microalgae classes, on the basis of the conservation, loss, and/or appearance of

  9. Community analysis of pigment patterns from 37 microalgae strains reveals new carotenoids and porphyrins characteristic of distinct strains and taxonomic groups.

    PubMed

    Serive, Benoît; Nicolau, Elodie; Bérard, Jean-Baptiste; Kaas, Raymond; Pasquet, Virginie; Picot, Laurent; Cadoret, Jean-Paul

    2017-01-01

    Phytoplankton, with an estimated 30 000 to 1 000 000 species clustered in 12 phyla, presents a high taxonomic and ecophysiological diversity, reflected by the complex distribution of pigments among the different algal classes. High performance liquid chromatography is the gold standard method for qualitative and quantitative analysis of phytoplankton pigments in seawater and culture samples, but only a few pigments can be used as robust chemotaxonomic markers. A major challenge is thus to identify new ones, characteristic of a strain, species, class or taxon that cannot be currently identified on the basis of its pigment signature. Using an optimized extraction process coupled to a HPLC de-replication strategy, we examined the pigment composition of 37 microalgae strains, representative of the broad taxonomic diversity of marine and freshwater species (excluding cyanobacteria). For each species, the major pigments already described were unambiguously identified. We also observed the presence of several minor unidentified pigments in each chromatogram. The global analysis of pigment compositions revealed a total of 124 pigments, including 98 pigments or derivatives unidentified using the standards. Absorption spectra indicated that 35 corresponded to chlorophyll/porphyrin derivatives, 57 to carotenoids and six to derivatives having both spectral signatures. Sixty-one of these unidentified or new carotenoids and porphyrin derivatives were characteristic of particular strains or species, indicating their possible use as highly specific chemotaxonomic markers capable of identifying one strain out of the 37 selected. We developed a graphical analysis using Gephi software to give a clear representation of pigment communities among the various phytoplankton strains, and to reveal strain-characteristic and shared pigments. This made it possible to reconstruct the taxonomic evolution of microalgae classes, on the basis of the conservation, loss, and/or appearance of

  10. Surgical Management of Iatrogenic Pigment Dispersion Glaucoma

    PubMed Central

    Mierlo, Camille Van; Pinto, Luis Abegão

    2015-01-01

    ABSTRACT Introduction: Iatrogenic pigment dispersion syndrome generally originates from a repetitive, mechanical trauma to the pigmented posterior epithelium of the iris. This trauma can arise after intraocular surgery, most commonly due to an abnormal contact between the intraocular lens (IOL) and the iris. Whether surgical removal of this primary insult can lead to a successful intraocular pressure (IOP) control remains unclear. Methods: Case-series. Patients with IOP elevation and clinical signs of pigment dispersion were screened for a diagnosis of iatrogenic IOL-related pigment dispersion. Results: Three patients in which the IOL or the IOL-bag complex caused a pigment dispersion through a repetitive iris chafing were selected. In two cases, replacement of a sulcus-based single-piece IOL (patient 1) or a sub-luxated in-the-bag IOL (patient 2) by an anterior-chamber (AC) iris-fixed IOL led to a sustained decrease in IOP. In the third case, extensive iris atrophy and poor anatomical AC parameters for IOL implantation precluded further surgical intervention. Conclusion: IOL-exchange appears to be a useful tool in the management of iatrogenic pigment dispersion glaucoma due to inappropriate IOL implantation. This cause-oriented approach seems to be effective in controlling IOP, but should be offered only if safety criteria are met. How to cite this article: Van Mierlo C, Abegao Pinto L, Stalmans I. Surgical Management of Iatrogenic Pigment Dispersion Glaucoma. J Curr Glaucoma Pract 2015;9(1):28-32. PMID:26997830

  11. Exosomes released by keratinocytes modulate melanocyte pigmentation

    PubMed Central

    Cicero, Alessandra Lo; Delevoye, Cédric; Gilles-Marsens, Floriane; Loew, Damarys; Dingli, Florent; Guéré, Christelle; André, Nathalie; Vié, Katell; van Niel, Guillaume; Raposo, Graça

    2015-01-01

    Cells secrete extracellular vesicles (EVs), exosomes and microvesicles, which transfer proteins, lipids and RNAs to regulate recipient cell functions. Skin pigmentation relies on a tight dialogue between keratinocytes and melanocytes in the epidermis. Here we report that exosomes secreted by keratinocytes enhance melanin synthesis by increasing both the expression and activity of melanosomal proteins. Furthermore, we show that the function of keratinocyte-derived exosomes is phototype-dependent and is modulated by ultraviolet B. In sum, this study uncovers an important physiological function for exosomes in human pigmentation and opens new avenues in our understanding of how pigmentation is regulated by intercellular communication in both healthy and diseased states. PMID:26103923

  12. Exosomes released by keratinocytes modulate melanocyte pigmentation.

    PubMed

    Lo Cicero, Alessandra; Delevoye, Cédric; Gilles-Marsens, Floriane; Loew, Damarys; Dingli, Florent; Guéré, Christelle; André, Nathalie; Vié, Katell; van Niel, Guillaume; Raposo, Graça

    2015-06-24

    Cells secrete extracellular vesicles (EVs), exosomes and microvesicles, which transfer proteins, lipids and RNAs to regulate recipient cell functions. Skin pigmentation relies on a tight dialogue between keratinocytes and melanocytes in the epidermis. Here we report that exosomes secreted by keratinocytes enhance melanin synthesis by increasing both the expression and activity of melanosomal proteins. Furthermore, we show that the function of keratinocyte-derived exosomes is phototype-dependent and is modulated by ultraviolet B. In sum, this study uncovers an important physiological function for exosomes in human pigmentation and opens new avenues in our understanding of how pigmentation is regulated by intercellular communication in both healthy and diseased states.

  13. A chromoplast-specific carotenoid biosynthesis pathway is revealed by cloning of the tomato white-flower locus.

    PubMed

    Galpaz, Navot; Ronen, Gil; Khalfa, Zehava; Zamir, Dani; Hirschberg, Joseph

    2006-08-01

    Carotenoids and their oxygenated derivatives xanthophylls play essential roles in the pigmentation of flowers and fruits. Wild-type tomato (Solanum lycopersicum) flowers are intensely yellow due to accumulation of the xanthophylls neoxanthin and violaxanthin. To study the regulation of xanthophyll biosynthesis, we analyzed the mutant white-flower (wf). It was found that the recessive wf phenotype is caused by mutations in a flower-specific beta-ring carotene hyroxylase gene (CrtR-b2). Two deletions and one exon-skipping mutation in different CrtR-b2 wf alleles abolish carotenoid biosynthesis in flowers but not leaves, where the homologous CrtR-b1 is constitutively expressed. A second beta-carotene hydroxylase enzyme as well as flower- and fruit-specific geranylgeranyl diphosphate synthase, phytoene synthase, and lycopene beta-cyclase together define a carotenoid biosynthesis pathway active in chromoplasts only, underscoring the crucial role of gene duplication in specialized plant metabolic pathways. We hypothesize that this pathway in tomato was initially selected during evolution to enhance flower coloration and only later recruited to enhance fruit pigmentation. The elimination of beta-carotene hydroxylation in wf petals results in an 80% reduction in total carotenoid concentration, possibly caused by the inability of petals to store high concentrations of carotenoids other than xanthophylls and by degradation of beta-carotene, which accumulates as a result of the wf mutation but is not due to altered expression of genes in the biosynthetic pathway.

  14. Spectropolarimetry of Photosynthetic Pigments as Global Surface Biosignatures

    NASA Astrophysics Data System (ADS)

    Sparks, W. B.; Parenteau, M. N.; Blankenship, R. E.; Germer, T. A.; Meadows, V. S.; Telesco, C. M.

    2015-12-01

    Photosynthesis is an ancient metabolic process on the early Earth. The most primitive phototrophs used reductants such as H2, H2S, and Fe(II) and were widespread in marine, intertidal, and likely continental habitats. These anoxygenic phototrophs were the key primary producers for the first ~1 billion years before the evolution of oxygenic photosynthesis at 2.7 Ga. The potential clearly exists for this type of primitive photosynthesis to operate on habitable exoplanets. Anoxygenic phototrophs are not known to emit gases that are uniquely biogenic in origin, so we focus on surface pigments signatures as having the strongest promise to offer identifiable biosignatures for a pre-oxygenic habitable exoplanet. Following our earlier work that showed photosynthetic cyanobacteria yield a polarization signature potentially useful in remote sensing, here we seek to characterize the remotely detectable polarization biosignatures associated with anoxygenic phototrophs. The six major pigments of anoxygenic phototrophs (bacteriochlorophylls [Bchls]) absorb in the near-infrared (NIR) from ~705 - 1040 nm. The lower symmetry of the pigment structure relative to chlorophylls shifts the energy absorption bands to longer wavelengths. As a result, Bchls are well suited to absorbing the relatively higher flux of red and NIR radiation of M dwarf stars, the most abundant type of star in the Galaxy, as well as the plentiful flux of typical main sequence stars. Homochirality is a powerful biosignature, and because of the optical activity of biological molecules, it can, in principle, be remotely observed on macroscopic scales using circular polarization spectroscopy. Bchls and Chls are optically active molecules with several chiral centers, strongly interacting with the incident light. We measured the reflectance and transmission full Stokes polarization spectra of pure cultures of anoxygenic phototrophs and environmental samples of microbial mats, and found strong correlations between

  15. Diagnosis and management of facial pigmented macules.

    PubMed

    Lallas, Aimilios; Argenziano, Giuseppe; Moscarella, Elvira; Longo, Caterina; Simonetti, Vito; Zalaudek, Iris

    2014-01-01

    The differential diagnosis of pigmented macules on the mottled chronic sun-damaged skin of the face is challenging and includes lentigo maligna (LM), pigmented actinic (solar) keratosis, solar lentigo, and lichen-planus-like keratosis. Although dermatoscopy improves the diagnostic accuracy of the unaided eye, the accurate diagnosis and management of pigmented facial macules remains one of the most challenging scenarios in daily practice. This is related to the fact that pigmented actinic (solar) keratosis, lichen-planus-like keratosis, and LM may reveal overlapping criteria, making their differential diagnosis clinically difficult. For this reason, practical rules have been introduced, which should help to minimize the risk for inappropriate diagnosis and management of LM.

  16. Pigments of fly agaric (Amanita muscaria).

    PubMed

    Stintzing, Florian; Schliemann, Willibald

    2007-01-01

    The complex pigment pattern of fly agaric (Amanita muscaria) cap skins has been studied by LC-DAD and mass spectrometry. Among the betaxanthins the corresponding derivatives of serine, threonine, ethanolamine, alanine, Dopa, phenylalanine and tryptophan are reported for the first time to contribute to the pigment pattern of fly agarics. Betalamic acid, the chromophoric precursor of betaxanthins and betacyanins, muscaflavin and seco-dopas were also detected. Furthermore, the red-purple muscapurpurin and the red muscarubrin were tentatively assigned while further six betacyanin-like components could not be structurally allocated. Stability studies indicated a high susceptibility of pigment extracts to degradation which led to rapid colour loss thus rendering a complete characterization of betacyanin-like compounds impossible at present. Taking into account these difficulties the presented results may be a starting point for a comprehensive characterization of the pigment composition of fly agarics.

  17. Color characterization of coatings with diffraction pigments.

    PubMed

    Ferrero, A; Bernad, B; Campos, J; Perales, E; Velázquez, J L; Martínez-Verdú, F M

    2016-10-01

    Coatings with diffraction pigments present high iridescence, which needs to be characterized in order to describe their appearance. The spectral bidirectional reflectance distribution functions (BRDFs) of six coatings with SpectraFlair diffraction pigments were measured using the robot-arm-based goniospectrophotometer GEFE, designed and developed at CSIC. Principal component analysis has been applied to study the coatings of BRDF data. From data evaluation and based on theoretical considerations, we propose a relevant geometric factor to study the spectral reflectance and color gamut variation of coatings with diffraction pigments. At fixed values of this geometric factor, the spectral BRDF component due to diffraction is almost constant. Commercially available portable goniospectrophotometers, extensively used in several industries (automotive and others), should be provided with more aspecular measurement angles to characterize the complex reflectance of goniochromatic coatings based on diffraction pigments, but they would not require either more than one irradiation angle or additional out-of-plane geometries.

  18. Induction of Yellow Pigmentation in Serratia marcescens

    PubMed Central

    Trias, Joaquim; Viñas, Miquel; Guinea, Jesús; Lorén, José G.

    1988-01-01

    The appearance of yellow pigmentation in nonpigmented strains of Serratia sp. has been demonstrated to be due to the production of a muconic acid, 2-hydroxy-5-carboxymethylmuconic acid semialdehyde. The 3,4-dihydroxyphenylacetate 2,3-dioxygenase responsible for the synthesis of this muconic acid was induced in all strains tested. Another muconic acid, the β-cis-cis-carboxymuconic acid, could also be synthesized from 3,4-dihydroxybenzoate, but this product was not colored. Mutants that were unable to grow on tyrosine and produced yellow pigment were isolated from nonpigmented strains. These mutants had properties similar to those of the yellow-pigmented strains. The ability to produce pigment may be more widespread among Serratia marcescens strains than is currently known. PMID:16347803

  19. New Directions in Phthalocyanine Pigments

    NASA Technical Reports Server (NTRS)

    Vandemark, Michael R.

    1992-01-01

    The objectives were the following: (1) investigation of the synthesis of new phthalocyanines; (2) characterization of the new phthalocyanines synthesized; (3) investigate the properties of the newly synthesized phthalocyanines with emphasis on UV protection of plastics and coatings; and (4) utilize quantum mechanics to evaluate the structural relationships with possible properties and synthetic approaches. The proposed research targeted the synthesis of phthalocyanines containing an aromatic bridge between two phthalocyanine rings. The goal was to synthesize pigments which would protect plastics when exposed to the photodegradation effects of the sun in space. The stability and extended conjugation of the phthalocyanines offer a unique opportunity for energy absorption and numerous radiative and non-radiative energy loss mechanisms. Although the original targeted phthalocyanines were changed early in the project, several new and unique phthalocyanine compounds were prepared. The basic goals of this work were met and some unique and unexpected outcomes of the work were the result of the integral use of quantum mechanics and molecular modeling with the synthetic effort.

  20. Regressive evolution in Astyanax cavefish.

    PubMed

    Jeffery, William R

    2009-01-01

    A diverse group of animals, including members of most major phyla, have adapted to life in the perpetual darkness of caves. These animals are united by the convergence of two regressive phenotypes, loss of eyes and pigmentation. The mechanisms of regressive evolution are poorly understood. The teleost Astyanax mexicanus is of special significance in studies of regressive evolution in cave animals. This species includes an ancestral surface dwelling form and many con-specific cave-dwelling forms, some of which have evolved their recessive phenotypes independently. Recent advances in Astyanax development and genetics have provided new information about how eyes and pigment are lost during cavefish evolution; namely, they have revealed some of the molecular and cellular mechanisms involved in trait modification, the number and identity of the underlying genes and mutations, the molecular basis of parallel evolution, and the evolutionary forces driving adaptation to the cave environment.

  1. Gene expression analysis of zebrafish melanocytes, iridophores, and retinal pigmented epithelium reveals indicators of biological function and developmental origin.

    PubMed

    Higdon, Charles W; Mitra, Robi D; Johnson, Stephen L

    2013-01-01

    In order to facilitate understanding of pigment cell biology, we developed a method to concomitantly purify melanocytes, iridophores, and retinal pigmented epithelium from zebrafish, and analyzed their transcriptomes. Comparing expression data from these cell types and whole embryos allowed us to reveal gene expression co-enrichment in melanocytes and retinal pigmented epithelium, as well as in melanocytes and iridophores. We found 214 genes co-enriched in melanocytes and retinal pigmented epithelium, indicating the shared functions of melanin-producing cells. We found 62 genes significantly co-enriched in melanocytes and iridophores, illustrative of their shared developmental origins from the neural crest. This is also the first analysis of the iridophore transcriptome. Gene expression analysis for iridophores revealed extensive enrichment of specific enzymes to coordinate production of their guanine-based reflective pigment. We speculate the coordinated upregulation of specific enzymes from several metabolic pathways recycles the rate-limiting substrate for purine synthesis, phosphoribosyl pyrophosphate, thus constituting a guanine cycle. The purification procedure and expression analysis described here, along with the accompanying transcriptome-wide expression data, provide the first mRNA sequencing data for multiple purified zebrafish pigment cell types, and will be a useful resource for further studies of pigment cell biology.

  2. Micro-analytical evidence of origin and degradation of copper pigments found in Bohemian Gothic murals.

    PubMed

    Svarcová, Silvie; Hradil, David; Hradilová, Janka; Kocí, Eva; Bezdicka, Petr

    2009-12-01

    Correct identification of pigments and all accompanying phases found in colour layers of historical paintings are relevant for searching their origin and pigment preparation pathways and for specification of their further degradation processes. We successfully applied the analytical route combining non-destructive in situ X-ray fluorescence analyses with subsequent laboratory investigation of micro-samples by optical microscopy, scanning electron microscopy/energy-dispersive spectroscopy and X-ray powder micro-diffraction (micro-XRD) to obtain efficiently all the data relevant for mineralogical interpretations of the copper pigments origin. Cu salts (carbonates, chlorides, sulphates, etc.) used as pigments exist in a range of polymorphs with similar or identical composition. The efficiency of the micro-XRD for direct identification of such crystal phases present in micro-samples of colour layers was demonstrated in the presented paper. A new, until now unpublished, type of copper pigment--cumengeite, Pb(21)Cu(20)Cl(42)(OH)(40)--used as a blue pigment on a sacral wall painting in the Czech Republic was found by means of micro-XRD. Furthermore, azurite, malachite, paratacamite, atacamite and posnjakite were identified in fragments of colour layers of selected Gothic wall paintings. We found Cu-Zn arsenates indicating the natural origin of azurite and malachite; artificial malachite was distinguishable according to its typical spherulitic crystals. The corrosion of blue azurite to green basic Cu chloride was clearly evidenced on some places exposed to the action of salts and moisture-in a good agreement with the results of laboratory experiments, which also show that oxalic acid accelerates the corrosion of Cu pigments.

  3. Macular pigment and lutein supplementation in choroideremia.

    PubMed

    Duncan, Jacque L; Aleman, Tomas S; Gardner, Leigh M; De Castro, Elaine; Marks, Daniel A; Emmons, Jessica M; Bieber, Michelle L; Steinberg, Janet D; Bennett, Jean; Stone, Edwin M; MacDonald, Ian M; Cideciyan, Artur V; Maguire, Maureen G; Jacobson, Samuel G

    2002-03-01

    Choroideremia is an incurable X-linked retinal degeneration caused by mutations in the gene encoding Rab escort protein-1. A group of clinically defined and genotyped patients were studied to determine: (1) the degree of rod and cone dysfunction and structural abnormality in the central retina and the level of macular pigment; and (2) the response of macular pigment and foveal vision to a 6 month trial of supplementation with oral lutein (at 20 mg per day). Rod and cone-mediated function was measured with dark-adapted static perimetry; in vivo retinal structure was determined with optical coherence tomography; and macular pigment optical density was measured with heterochromatic flicker photometry. In this cohort of patients (ages 15-65 years), both rod- and cone-mediated central function declined with age as did central retinal thickness. Macular pigment levels did not differ between patients and male control subjects. Supplementation of oral lutein in a subset of patients led to an increase in serum lutein and macular pigment levels; absolute foveal sensitivity did not change. It is concluded that macular pigment density can be augmented by oral intake of lutein in patients with choroideremia. There was no short-term change in the central vision of the patients on the supplement, but long-term influences of lutein supplementation on disease natural history warrant further study.

  4. Microspectrophotometry of Arthropod Visual Screening Pigments

    PubMed Central

    Strother, G. K.; Casella, A. J.

    1972-01-01

    Absorption spectra of visual screening pigments obtained in vitro with a microspectrophotometer using frozen sections are given for the insects Musca domestica, Phormia regina, Libellula luctuosa, Apis mellifera (worker honeybee only), Drosophila melanogaster (wild type only) and the arachnids Lycosa baltimoriana and Lycosa miami. The spectral range covered is 260–700 nm for Lycosa and Drosophila and 310–700 nm for the remainder of the arthropods. A complete description of the instrumentation is given. For the flies, Phormia and Musca, light absorption by the yellow and red pigments is high from 310 to about 610 nm. This implies that for these insects there should be no wavelength shift in electroretinogram (ERG) results due to light leakage among neighboring ommatidia for this wavelength range. The same comment applies to Calliphora erythrocephala, which is known to have similar screening pigments. For some of the insects studied a close correspondence is noted between screening pigment absorption spectra and spectral sensitivity curves for individual photoreceptors, available in the literature. In some cases the screening pigment absorption spectra can be related to chemical extraction results, with the general observation that some of the in vitro absorption peaks are shifted to the red. The Lycosa, Apis, and Libellula dark red pigments absorb strongly over a wide spectral range and therefore prevent chemical identification. PMID:4623852

  5. Beyond spectral tuning: human cone visual pigments adopt different transient conformations for chromophore regeneration.

    PubMed

    Srinivasan, Sundaramoorthy; Cordomí, Arnau; Ramon, Eva; Garriga, Pere

    2016-03-01

    Human red and green visual pigments are seven transmembrane receptors of cone photoreceptor cells of the retina that mediate color vision. These pigments share a very high degree of homology and have been assumed to feature analogous structural and functional properties. We report on a different regeneration mechanism among red and green cone opsins with retinal analogs using UV-Vis/fluorescence spectroscopic analyses, molecular modeling and site-directed mutagenesis. We find that photoactivated green cone opsin adopts a transient conformation which regenerates via an unprotonated Schiff base linkage with its natural chromophore, whereas red cone opsin forms a typical protonated Schiff base. The chromophore regeneration kinetics is consistent with a secondary retinal uptake by the cone pigments. Overall, our findings reveal, for the first time, structural differences in the photoactivated conformation between red and green cone pigments that may be linked to their molecular evolution, and support the proposal of secondary retinal binding to visual pigments, in addition to binding to the canonical primary site, which may serve as a regulatory mechanism of dark adaptation in the phototransduction process.

  6. Identification of the silkworm quail gene reveals a crucial role of a receptor guanylyl cyclase in larval pigmentation.

    PubMed

    Yuasa, Masashi; Kiuchi, Takashi; Banno, Yutaka; Katsuma, Susumu; Shimada, Toru

    2016-01-01

    Diverse color patterns on the integument of lepidopteran larvae play important roles in their survival through camouflage, mimicry, sexual signaling, and aposematism. In the silkworm Bombyx mori, many color pattern variations have been preserved in inbred strains making them a good model for elucidating the molecular mechanisms that underlie color pattern formation. In this study, we focused on the silkworm quail (q) mutant, which exhibits abnormalities in multiple pigment biosynthesis pathways. Positional cloning of the q gene revealed that disruption of a guanylyl cyclase gene, BmGC-I, is responsible for its abnormal pigmentation. In q mutants, we identified a 16-bp deletion in the BmGC-I transcript, resulting in the production of a premature stop codon. Knockout of the BmGC-I gene resulted in the q-like abnormal pigmentation, thereby demonstrating that the BmGC-I gene is involved in the pigment biosynthesis pathway in the integument. Moreover, quantitative reverse transcription polymerase chain reaction showed that BmGC-I was strongly expressed in the fourth instar on day 2. Our results suggest that BmGC-I deficiency affects the pigment biosynthesis pathway, which supports the involvement of guanylyl cyclase in larval coloration.

  7. Pigmented eccrine poroma: dermoscopic and confocal features

    PubMed Central

    Bombonato, Caterina; Piana, Simonetta; Moscarella, Elvira; Lallas, Aimillios; Argenziano, Giuseppe; Longo, Caterina

    2016-01-01

    Eccrine poroma is a rare benign adnexal tumor of epithelial cells originating from the terminal ductal portion of the sweat glands that is typically located on palms and soles, although other cutaneous sites can be affected [1]. It is usually nonpigmented even if there is a pigmented variant that corresponds to 17% of cases and it is usually underdiagnosed, since it is mistakenly confused with other pigmented tumors [2,3]. Dermoscopy and reflectance confocal microscopy (RCM) may assist in the correct diagnosis of this tumor. Herein, we report one case of pigmented eccrine poroma (PEP) that simulated clinically a cutaneous melanoma or a basal cell carcinoma. Dermoscopy and RCM excluded the possibilities of those two diagnoses; the overall confocal findings were suggestive for a benign epithelial tumor. Histology was fundamental to diagnose this lesion as a pigmented eccrine poroma. Even if the diagnosis of eccrine poroma remains histopathological still, as in this case report, noninvasive tools such as dermoscopy and RCM examinations can be of help to rule out the diagnosis of melanoma. Larger studies on this rare pigmented variant of eccrine poroma could shed new light on the identification of specific diagnostic dermoscopic and confocal features. PMID:27648386

  8. Iris pigment epithelial cysts in a newborn

    PubMed Central

    Zargar, Shabnam; Prendiville, Kevin John; Martinez, Eladio

    2016-01-01

    Purpose: We report a case of iris pigment epithelial cysts in a newborn and discuss the importance of an accurate diagnosis for prevention of amblyopia. Methods: We describe a case of an abnormal red reflex seen on a newborn exam. Results: A full-term female born via normal spontaneous vaginal delivery without any complications was seen in the newborn nursery. She was noted to have an abnormal eye exam. Pupils were large with circular dark excrescences of the iris pigment epithelium. She was referred to a pediatric ophthalmologist where she was noted to fixate and follow faces. No afferent pupillary defect was seen. OD red reflex was normal whereas OS red reflex was blocked mostly by dark excrescences. A 2–3 mm dark brown lesion was seen in the OD iris and a 3–5 mm dark brown lesion was seen in the OS iris, consistent with a pupillary iris pigment epithelial cyst. Central visual axis was clear OU. Glaucoma was not present and patching was not performed. Observations and clinical photographs were recommended with follow-up in three months. Conclusion: Iris pigment epithelial cysts are uncommonly seen in children. The primary care provider first seeing a newborn must be aware of lesions obscuring a red reflex with appropriate follow-up. Follow-up in three months with IOP measurements is recommended. Iris pigment epithelial cysts in children may be a cause of amblyopia, thus prompt evaluation is important for prognostic purposes and the prevention of amblyopia. PMID:27625966

  9. Inadvertent polychlorinated biphenyls in commercial paint pigments.

    PubMed

    Hu, Dingfei; Hornbuckle, Keri C

    2010-04-15

    A polychlorinated biphenyl (PCB) that was not produced as part of the Aroclor mixtures banned in the 1980s was recently reported in air samples collected in Chicago, Philadelphia, the Arctic, and several sites around the Great Lakes. In Chicago, the congener 3,3'-dichlorobiphenyl or PCB11 was found to be the fifth most concentrated congener and ubiquitous throughout the city. The congener exhibited strong seasonal concentration trends that suggest volatilization of this compound from common outdoor surfaces. Due to these findings and also the compound's presence in waters that received waste from paint manufacturing facilities, we hypothesized that PCB11 may be present in current commercial paint. In this study we measured PCBs in paint sold on the current retail market. We tested 33 commercial paint pigments purchased from three local paint stores. The pigment samples were analyzed for all 209 PCB congeners using gas chromatography with tandem mass spectrometry (GC-MS/MS). More than 50 PCB congeners including several dioxin-like PCBs were detected, and the PCB profiles varied due to different types of pigments and different manufacturing processes. PCB congeners were detected in azo and phthalocyanine pigments which are commonly used in paint but also in inks, textiles, paper, cosmetics, leather, plastics, food and other materials. Our findings suggest several possible mechanisms for the inadvertent production of specific PCB congeners during the manufacturing of paint pigments.

  10. Investigations of biomimetic light energy harvesting pigments

    SciTech Connect

    Van Patten, P.G.; Donohoe, R.J.; Lindsey, J.S.; Bocian, D.F.

    1998-12-01

    This is the final report of a three-year, Laboratory Directed Research and Development (LDRD) project at Los Alamos National Laboratory (LANL). Nature uses chlorophyll and other porphyrinic pigments to capture and transfer light energy as a preliminary step in photosynthesis. The design of synthetic assemblies of light harvesting and energy directing pigments has been explored through synthesis and characterization of porphyrin oligomers. In this project, pigment electronic and vibrational structures have been explored by electrochemistry and dynamic and static optical measurements. Transient absorption data reveal energy transfer between pigments with lifetimes on the order of 20--200 picoseconds, while Raman data reveal that the basic porphyrin core structure is unperturbed relative to the individual monomer units. These two findings, along with an extensive series of experiments on the oxidized oligomers, reveal that coupling between the pigments is fundamentally weak, but sufficient to allow facile energy transfer as the predominant excited state process. Modeling of the expected quantum yields for energy transfer within a variety of arrays was accomplished, thereby providing a tool to guide synthetic goals.

  11. Pigments in avocado tissue and oil.

    PubMed

    Ashton, Ofelia B O; Wong, Marie; McGhie, Tony K; Vather, Rosheila; Wang, Yan; Requejo-Jackman, Cecilia; Ramankutty, Padmaja; Woolf, Allan B

    2006-12-27

    Pigments are important contributors to the appearance and healthful properties of both avocado fruits and the oils extracted from these fruits. This study determined carotenoid and chlorophyll pigment concentrations in the skin and three sections of the flesh (outer dark green, middle pale green, and inner yellow flesh-nearest the seed) and anthocyanin concentrations in the skin of Hass avocado during ripening at 20 degrees C. Pigments were extracted from frozen tissue with acetone and measured using high-performance liquid chromatography. Pigments were also measured in the oil extracted from freeze-dried tissue sections by an accelerated solvent extraction system using hexane. Carotenoids and chlorophylls identified in the skin, flesh, and oil were lutein, alpha-carotene, beta-carotene, neoxanthin, violaxanthin, zeaxanthin, antheraxanthin, chlorophylls a and b, and pheophytins a and b with the highest concentrations of all pigments in the skin. Chlorophyllides a and b were identified in the skin and flesh tissues only. As the fruit ripened and softened, the skin changed from green to purple/black, corresponding to changes in skin hue angle, and a concomitant increase in cyanidin 3-O-glucoside and the loss of chlorophyllide a. In flesh tissue, chroma and lightness values decreased with ripening, with no changes in hue angle. The levels of carotenoids and chlorophylls did not change significantly during ripening. As fruit ripened, the total chlorophyll level in the oil from the flesh sections remained constant but declined in the oil extracted from the skin.

  12. Population diversity and adaptive evolution in keratinization genes: impact of environment in shaping skin phenotypes.

    PubMed

    Gautam, Pramod; Chaurasia, Amit; Bhattacharya, Aniket; Grover, Ritika; Mukerji, Mitali; Natarajan, Vivek T

    2015-03-01

    Several studies have demonstrated the role of climatic factors in shaping skin phenotypes, particularly pigmentation. Keratinization is another well-designed feature of human skin, which is involved in modulating transepidermal water loss (TEWL). Although this physiological process is closely linked to climate, presently it is not clear whether genetic diversity is observed in keratinization and whether this process also responds to the environmental pressure. To address this, we adopted a multipronged approach, which involved analysis of 1) copy number variations in diverse Indian and HapMap populations from varied geographical regions; 2) genetic association with geoclimatic parameters in 61 populations of dbCLINE database in a set of 549 genes from four processes namely keratinization, pigmentation, epidermal differentiation, and housekeeping functions; 3) sequence divergence in 4,316 orthologous promoters and corresponding exonic regions of human and chimpanzee with macaque as outgroup, and 4) protein sequence divergence (Ka/Ks) across nine vertebrate classes, which differ in their extent of TEWL. Our analyses demonstrate that keratinization and epidermal differentiation genes are under accelerated evolution in the human lineage, relative to pigmentation and housekeeping genes. We show that this entire pathway may have been driven by environmental selection pressure through concordant functional polymorphisms across several genes involved in skin keratinization. Remarkably, this underappreciated function of skin may be a crucial determinant of adaptation to diverse environmental pressures across world populations.

  13. Polycyclic aromatic hydrocarbons - Primitive pigment systems in the prebiotic environment

    NASA Technical Reports Server (NTRS)

    Deamer, D. W.

    1992-01-01

    The chemical evolution of meteoritic organics in the primitive earth is examined experimentally with attention given to the photochemical effects of hydrocarbon/water mixtures. Also addressed are the generation of amphiphilic products by photochemical reactions and the transduction of light energy into potentially useful forms. Polycyclic aromatic hydrocarbons (PAHs) absorb light and exist in carbonaceous chondrites; PAHs are therefore examined as primitive pigments by means of salt solutions with pyrene, fluoranthene, and pyrene derivatives with hexadecane. The hexadecane undergoes photochemical oxidation and yields long-chain amphiphiles with oxygen supplied by water, and acid pH shifts also occur. PAHs are also tested in lipid bilayer membranes to examine light-energy transduction. Protons are found to accumulate within the membrane-bounded volume to form proton gradients, and this reaction is theorized to be a good model of primitive photochemical reactions that related to the transduction of light energy into useable forms.

  14. Retinal Pigment Epithelium Tears: Risk Factors, Mechanism and Therapeutic Monitoring.

    PubMed

    Clemens, Christoph R; Eter, Nicole

    2016-01-01

    Tears of the retinal pigment epithelium (RPE) are most commonly associated with vascularised RPE detachment due to age-related macular degeneration (AMD), and they usually involve a deleterious loss in visual acuity. Recent studies suggest an increase in RPE tear incidences since the introduction of anti-vascular endothelial growth factor (anti-VEGF) therapies as well as a temporal association between the tear event and the intravitreal injection. As the number of AMD patients and the number of administered anti-VEGF injections increase, both the challenge of RPE tear prevention and the treatment after RPE tear formation have become more important. At the same time, the evolution of retinal imaging has significantly contributed to a better understanding of RPE tear development in recent years. This review summarises the current knowledge on RPE tear development, predictive factors, and treatment strategies before and after RPE tear formation.

  15. [Notalgia paresthetica, "posterior pigmented pruritic patch" and macular amyloidosis. Three stages of a disease].

    PubMed

    Cerroni, L; Kopera, D; Soyer, H P; Kerl, H

    1993-12-01

    We report on nine cases of notalgia paresthetica, a cutaneous condition that has rarely been described in the dermatological literature and is characterized by localized pruritus, burning and hyperesthesia and/or paresthesia on the back. Histological and immunohistochemical studies have not clarified the pathogenesis of this disease. Several factors might be involved in various cases, including increased cutaneous innervation and neuropathy. The so-called posterior pigmented pruritic patch and macular amyloidosis may be considered as progressive evolutional stages of notalgia paresthetica.

  16. Pretreatment of pigments to prepare liquids for enteric coating.

    PubMed

    Bölcskei, E; Bajdik, J; Müller, J; Knop, K; Kleinebudde, P; Pintye-Hódi, K

    2008-07-01

    Film coating fluids commonly contain different pigments. The objective of this work was a study of the distribution of these particles in the coating film. Different pretreatment forms (pigment suspension, pigment paste and untreated pigments) were applied. They were incorporated into a Eudragit L 30 D-55 dispersion. The surface roughness and the mechanical properties of the free films indicated, that the most homogeneous film was obtained with the pigment paste. The homogeneity of the film was investigated by mechanical testing. The protective effect of the coating did not vary with the application of pigments in different forms, but the appearance of the coated tablets underwent a considerable change.

  17. Detection of Pigment Networks in Dermoscopy Images

    NASA Astrophysics Data System (ADS)

    Eltayef, Khalid; Li, Yongmin; Liu, Xiaohui

    2017-02-01

    One of the most important structures in dermoscopy images is the pigment network, which is also one of the most challenging and fundamental task for dermatologists in early detection of melanoma. This paper presents an automatic system to detect pigment network from dermoscopy images. The design of the proposed algorithm consists of four stages. First, a pre-processing algorithm is carried out in order to remove the noise and improve the quality of the image. Second, a bank of directional filters and morphological connected component analysis are applied to detect the pigment networks. Third, features are extracted from the detected image, which can be used in the subsequent stage. Fourth, the classification process is performed by applying feed-forward neural network, in order to classify the region as either normal or abnormal skin. The method was tested on a dataset of 200 dermoscopy images from Hospital Pedro Hispano (Matosinhos), and better results were produced compared to previous studies.

  18. Predicting Phenotype from Genotype: Normal Pigmentation*

    PubMed Central

    Valenzuela, Robert K.; Henderson, Miquia S.; Walsh, Monica H.; Garrison, Nanibaa’A.; Kelch, Jessica T.; Cohen-Barak, Orit; Erickson, Drew T.; Meaney, F. John; Walsh, J. Bruce; Cheng, Keith C.; Ito, Shosuke; Wakamatsu, Kazumasa; Frudakis, Tony; Thomas, Matthew; Brilliant, Murray H.

    2013-01-01

    Genetic information in forensic studies is largely limited to CODIS data and the ability to match samples and assign them to an individual. However, there are circumstances, in which a given DNA sample does not match anyone in the CODIS database, and no other information about the donor is available. In this study, we determined 75 SNPs in 24 genes (previously implicated in human or animal pigmentation studies) for the analysis of single- and multi-locus associations with hair, skin, and eye color in 789 individuals of various ethnic backgrounds. Using multiple linear regression modeling, five SNPs in five genes were found to account for large proportions of pigmentation variation in hair, skin, and eyes in our across-population analyses. Thus, these models may be of predictive value to determine an individual’s pigmentation type from a forensic sample, independent of ethnic origin. PMID:20158590

  19. Pigments which reflect infrared radiation from fire

    DOEpatents

    Berdahl, P.H.

    1998-09-22

    Conventional paints transmit or absorb most of the intense infrared (IR) radiation emitted by fire, causing them to contribute to the spread of fire. The present invention comprises a fire retardant paint additive that reflects the thermal IR radiation emitted by fire in the 1 to 20 micrometer ({micro}m) wavelength range. The important spectral ranges for fire control are typically about 1 to about 8 {micro}m or, for cool smoky fires, about 2 {micro}m to about 16 {micro}m. The improved inventive coatings reflect adverse electromagnetic energy and slow the spread of fire. Specific IR reflective pigments include titanium dioxide (rutile) and red iron oxide pigments with diameters of about 1 {micro}m to about 2 {micro}m and thin leafing aluminum flake pigments. 4 figs.

  20. Pigments which reflect infrared radiation from fire

    DOEpatents

    Berdahl, Paul H.

    1998-01-01

    Conventional paints transmit or absorb most of the intense infrared (IR) radiation emitted by fire, causing them to contribute to the spread of fire. The present invention comprises a fire retardant paint additive that reflects the thermal IR radiation emitted by fire in the 1 to 20 micrometer (.mu.m) wavelength range. The important spectral ranges for fire control are typically about 1 to about 8 .mu.m or, for cool smoky fires, about 2 .mu.m to about 16 .mu.m. The improved inventive coatings reflect adverse electromagnetic energy and slow the spread of fire. Specific IR reflective pigments include titanium dioxide (rutile) and red iron oxide pigments with diameters of about 1 .mu.m to about 2 .mu.m and thin leafing aluminum flake pigments.

  1. An intracellular anion channel critical for pigmentation.

    PubMed

    Bellono, Nicholas W; Escobar, Iliana E; Lefkovith, Ariel J; Marks, Michael S; Oancea, Elena

    2014-12-16

    Intracellular ion channels are essential regulators of organellar and cellular function, yet the molecular identity and physiological role of many of these channels remains elusive. In particular, no ion channel has been characterized in melanosomes, organelles that produce and store the major mammalian pigment melanin. Defects in melanosome function cause albinism, characterized by vision and pigmentation deficits, impaired retinal development, and increased susceptibility to skin and eye cancers. The most common form of albinism is caused by mutations in oculocutaneous albinism II (OCA2), a melanosome-specific transmembrane protein with unknown function. Here we used direct patch-clamp of skin and eye melanosomes to identify a novel chloride-selective anion conductance mediated by OCA2 and required for melanin production. Expression of OCA2 increases organelle pH, suggesting that the chloride channel might regulate melanin synthesis by modulating melanosome pH. Thus, a melanosomal anion channel that requires OCA2 is essential for skin and eye pigmentation.

  2. ABCF1 extrinsically regulates retinal pigment epithelial cell phagocytosis

    PubMed Central

    Guo, Feiye; Ding, Ying; Caberoy, Nora; Alvarado, Gabriela; Wang, Feng; Chen, Rui; Li, Wei

    2015-01-01

    Phagocytosis of shed photoreceptor outer segments (POSs) by retinal pigment epithelial (RPE) cells is critical to retinal homeostasis and shares many conserved signaling pathways with other phagocytes, including extrinsic regulations. Phagocytotic ligands are the key to cargo recognition, engulfment initiation, and activity regulation. In this study, we identified intracellular protein ATP-binding cassette subfamily F member 1 (ABCF1) as a novel RPE phagocytotic ligand by a new approach of functional screening. ABCF1 was independently verified to extrinsically promote phagocytosis of shed POSs by D407 RPE cells. This finding was further corroborated with primary RPE cells and RPE explants. Internalized POS vesicles were colocalized with a phagosome marker, suggesting that ABCF1-mediated engulfment is through a phagocytic pathway. ABCF1 was released from apoptotic cells and selectively bound to shed POS vesicles and apoptotic cells, possibly via externalized phosphatidylserine. ABCF1 is predominantly expressed in POSs and colocalized with the POS marker rhodopsin, providing geographical convenience for regulation of RPE phagocytosis. Collectively these results suggest that ABCF1 is released from and binds to shed POSs in an autocrine manner to facilitate RPE phagocytosis through a conserved pathway. Furthermore, the new approach is broadly applicable to many other phagocytes and will enable systematic elucidation of their ligands to understand extrinsic regulation and cargo recognition. PMID:25904329

  3. Green pigments of the Pompeian artists' palette

    NASA Astrophysics Data System (ADS)

    Aliatis, Irene; Bersani, Danilo; Campani, Elisa; Casoli, Antonella; Lottici, Pier Paolo; Mantovan, Silvia; Marino, Iari-Gabriel; Ospitali, Francesca

    2009-08-01

    Green colored samples on wall paintings and green powder from a pigment pot found in Pompeii area are investigated by micro-Raman, FT-IR and, for one sample, SEM-EDX. To obtain the green color, green earths and malachite were used, together with mixture of Egyptian blue and yellow ochre. The mineralogical identification of the green earths has been attempted through the comparison of the vibrational features, discriminating between celadonite and glauconite spectra. Traces of a modern synthetic pigment containing copper phthalocyanine were found in a fresco fragment.

  4. The focal differentiation of pigment cells.

    PubMed

    Whimster, I W

    1979-05-01

    A study has been made of the normal development and of the regeneration after excision of the groups of large pigment cells which form the spotted skin pattern of the gecko Eublepharis macularius, together with the effects of neonatal graft transplantation on this pattern. The results all indicate strongly that such groups of specialized pigment cells are not clones but the product of an induction process. This is then compared with the neural reflex mechanism by which the skin pattern of Chamaeoleo dilepis is formed.

  5. RISK ASSESSMENT FOR THE DYE AND PIGMENT ...

    EPA Pesticide Factsheets

    This risk assessment calculates the maximum loadings of constituents found in dyes and pigment industries waste streams which can be disposed in different types of waste management units without causing health benchmarks to be exceeded at plausible receptor locations. The assessment focuses on potential risks from volatilization and leaching to groundwater of constituents disposed in surface impoundments and landfills with either clay liners or composite liners. This product will be used by EPA decision makers to assist in determining whether certain waste streams generated by the dyes and pigments industries should be designated as hazardous.

  6. Fundamental molecules of life are pigments which arose and evolved to dissipate the solar spectrum

    NASA Astrophysics Data System (ADS)

    Michaelian, K.; Simeonov, A.

    2015-02-01

    The driving force behind the origin and evolution of life has been the thermodynamic imperative of increasing the entropy production of the biosphere through increasing the global solar photon dissipation rate. In the upper atmosphere of today, oxygen and ozone derived from life processes are performing the short wavelength UVC and UVB dissipation. On Earth's surface, water and organic pigments in water facilitate the near UV and visible photon dissipation. The first organic pigments probably formed, absorbed, and dissipated at those photochemically active wavelengths in the UVC that could have reached Earth's surface during the Archean. Proliferation of these pigments can be understood as an autocatalytic photochemical process obeying non-equilibrium thermodynamic directives related to increasing solar photon dissipation rate. Under these directives, organic pigments would have evolved over time to increase the global photon dissipation rate by; (1) increasing the ratio of their effective photon cross sections to their physical size, (2) decreasing their electronic excited state life times, (3) quenching radiative de-excitation channels (e.g. fluorescence), (4) covering ever more completely the prevailing solar spectrum, and (5) proliferating and dispersing to cover an ever greater surface area of Earth. From knowledge of the evolution of the spectrum of G-type stars, and considering the most probable history of the transparency of Earth's atmosphere, we construct the most probable Earth surface solar spectrum as a function of time and compare this with the history of molecular absorption maxima obtained from the available data in the literature. This comparison supports the conjecture that many fundamental molecules of life are pigments which arose and evolved to dissipate the solar spectrum, supports the thermodynamic dissipation theory for the origin of life, constrains models for Earth's early atmosphere, and sheds some new light on the origin of

  7. The tryptophan aminotransferase Tam1 catalyses the single biosynthetic step for tryptophan-dependent pigment synthesis in Ustilago maydis.

    PubMed

    Zuther, Katja; Mayser, Peter; Hettwer, Ursula; Wu, Wenying; Spiteller, Peter; Kindler, Bernhard L J; Karlovsky, Petr; Basse, Christoph W; Schirawski, Jan

    2008-04-01

    Tryptophan is a precursor for many biologically active secondary metabolites. We have investigated the origin of indole pigments first described in the pityriasis versicolor-associated fungus Malassezia furfur. Some of the identified indole pigments have properties potentially explaining characteristics of the disease. As M. furfur is not amenable to genetic manipulation, we used Ustilago maydis to investigate the pathway leading to pigment production from tryptophan. We show by high-performance liquid chromatography, mass spectrometry and nuclear magnetic resonance analysis that the compounds produced by U. maydis include those putatively involved in the etiology of pityriasis versicolor. Using a reverse genetics approach, we demonstrate that the tryptophan aminotransferase Tam1 catalyses pigment biosynthesis by conversion of tryptophan into indolepyruvate. A forward genetics approach led to the identification of mutants incapable of producing the pigments. These mutants were affected in the sir1 gene, presumably encoding a sulphite reductase. In vitro experiments with purified Tam1 showed that 2-oxo 4-methylthio butanoate serves as a substrate linking tryptophan deamination to sulphur metabolism. We provide the first direct evidence that these indole pigments form spontaneously from indolepyruvate and tryptophan without any enzymatic activity. This suggests that compounds with a proposed function in M. furfur-associated disease consist of indolepyruvate-derived spontaneously generated metabolic by-products.

  8. Locally differentiated cryptic pigmentation in the freshwater isopod Asellus aquaticus.

    PubMed

    Hargeby, A; Stoltz, J; Johansson, J

    2005-05-01

    A repeated pattern of background colour matching in animals is an indication that pigmentation may be cryptic. Here, we examine the relationship between pigmentation of the freshwater isopod Asellus aquaticus and background darkness in 29 lakes, wetlands and ponds in Southern Sweden. The results show that Asellus pigmentation was correlated with substrate darkness across all localities. In seven localities, in which two contrasting substrate types were noted, Asellus populations were differentiated with respect to pigmentation. These findings thus provide phenomenological support for cryptic pigmentation in Asellus. Pigmentation generally increased with body size, but the relationship between pigmentation and size differed among localities, possibly as a result of differences in correlational selection on pigmentation and size. Selection thus appears to have resulted in local differentiation over a small spatial scale, even within lakes and wetlands. This differentiation is a likely cause behind elevated phenotype variation noted in localities with two substrate types, suggesting that habitat heterogeneity promotes genetic diversity.

  9. Separation of Chloroplast Pigments Using Reverse Phase Chromatography.

    ERIC Educational Resources Information Center

    Reese, R. Neil

    1997-01-01

    Presents a protocol that uses reverse phase chromatography for the separation of chloroplast pigments. Provides a simple and relatively safe procedure for use in teaching laboratories. Discusses pigment extraction, chromatography, results, and advantages of the process. (JRH)

  10. Co-evolution of HAD phosphatase and hotdog-fold thioesterase domain function in the menaquinone-pathway fusion proteins BF1314 and PG1653.

    PubMed

    Wang, Min; Song, Feng; Wu, Rui; Allen, Karen N; Mariano, Patrick S; Dunaway-Mariano, Debra

    2013-09-02

    The function of a Bacteroidetes menaquinone biosynthetic pathway fusion protein comprised of an N-terminal haloacid dehalogenase (HAD) family domain and a C-terminal hotdog-fold family domain is described. Whereas the thioesterase domain efficiently catalyzes 1,4-dihydroxynapthoyl-CoA hydrolysis, an intermediate step in the menaquinone pathway, the HAD domain is devoid of catalytic activity. In some Bacteroidetes a homologous, catalytically active 1,4-dihydroxynapthoyl-CoA thioesterase replaces the fusion protein. Following the gene fusion event, sequence divergence resulted in a HAD domain that functions solely as the oligomerization domain of an otherwise inactive thioesterase domain.

  11. Co-evolution of HAD Phosphatase and Hotdog-fold Thioesterase Domain Function in the Menaquinone-Pathway Fusion Proteins BF1314 and PG1653

    PubMed Central

    Wang, Min; Song, Feng; Wu, Rui; Allen, Karen N.; Mariano, Patrick S.; Dunaway-Mariano, Debra

    2013-01-01

    The function of a Bacteroidetes menaquinone biosynthetic pathway fusion protein comprised of an N-terminal haloacid dehalogenase (HAD) family domain and a C-terminal hotdog-fold family domain is described. Whereas the thioesterase domain efficiently catalyzes 1,4-dihydroxynapthoyl-CoA hydrolysis, an intermediate step in the menaquinone pathway, the HAD domain is devoid of catalytic activity. In some Bacteroidetes a homologous, catalytically active 1,4-dihydroxynapthoyl-CoA thioesterase replaces the fusion protein. Following the gene fusion event, sequence divergence resulted in a HAD domain that functions solely as the oligomerization domain of an otherwise inactive thioesterase domain. PMID:23851007

  12. Pigmented poroma with unusual location and dermatoscopic features

    PubMed Central

    Kassuga, Luiza E. B. P.; Jeunon, Thiago; Sousa, Maria Auxiliadora Jeunon; Campos-do-Carmo, Gabriella

    2012-01-01

    Poroma is a benign adnexal neoplasm with atn “poroid”/ductal differentiation that mimics benign and malignant skin tumors. Histopathology shows circumscribed proliferation of poroid cells intermingled with a variable number of cuticular cells. We report a case of pigmented poroma located on the face that simulated clinically and dermatoscopically a pigmented basal cell carcinoma. The features of pigmented and non-pigmented poromas were revisited in order to assist in the diagnosis. PMID:23785609

  13. The Use of HPLC for the Characterization of Phytoplankton Pigments.

    PubMed

    Garrido, José L; Roy, Suzanne

    2015-01-01

    HPLC is still the technique of choice for the analysis and characterization of phytoplankton pigments. In this chapter we describe procedures for sample preparation and pigment extraction, and the use of octyl silica columns and pyridine-containing mobile phases to separate chlorophylls and carotenoids. The identification of pigments on the basis of their retention times and visible spectra, the preparation of pigment standards, and the quantitative analysis by either external or internal standard procedures are also described.

  14. Prostaglandin-induced iridial pigmentation in primates.

    PubMed

    Selén, G; Stjernschantz, J; Resul, B

    1997-02-01

    Latanoprost, a new ocular hypotensive prostaglandin F2 alpha analogue prodrug, was found to induce increased pigmentation of monkey irides in chronic toxicity studies. This prompted us to investigate the effect of naturally occurring prostaglandins on the monkey iris to determine whether this pigmentary effect is unique for latanoprost or whether it is a class effect of prostaglandins. PGF2 alpha-isopropyl ester (IE), PGE2-IE and latanoprost were applied topically to cynomolgus monkey eyes for 18-44 weeks. One eye of each animal was treated, while the other served as control. In addition, latanoprost was applied to sympathectomized monkey eyes. PGF2 alpha-IE, PGE2-IE, as well as latanoprost, induced increased pigmentation in the monkey eye. The first signs of this effect were seen after about two months of treatment. Latanoprost also induced increased pigmentation in sympathectomized eyes. It is concluded that both naturally occurring prostaglandins and their synthetic analogues can induce increased iridial pigmentation in cynomolgus monkeys, and that the effect does not require the presence of sympathetic nerves.

  15. Human pigmentation genes under environmental selection

    PubMed Central

    2012-01-01

    Genome-wide association studies and comparative genomics have established major loci and specific polymorphisms affecting human skin, hair and eye color. Environmental changes have had an impact on selected pigmentation genes as populations have expanded into different regions of the globe. PMID:23110848

  16. Pigment Deposition in the Rat Retina.

    PubMed

    Hojman, Anne S; Otzen, Louise W D; Schrøder-Hansen, Lise Maj; Wegener, Karen M

    2015-08-01

    Incidental findings in the rat eye are not uncommon in acute and long-term toxicological studies. These findings can be associated with a number of causes unrelated to treatment with the test article, including congenital malformation, trauma, infection, metabolic disease, genetic predisposition, and age-related changes. The occurrence of pigment deposition in the retina of Wistar Hannover (Crl:WI (Han)) rats in a 4-week toxicity study is reported in this communication. The microscopic examination of the eyes in the 4-week toxicity study revealed focal yellow-brown pigment deposits in the retina, mainly located in the ganglion cell layer. The retinal pigment deposits were randomly distributed in the control and treated groups and were considered incidental. The deposits were clearly positive for ferric iron in the Perls' stain but not for lipofuscin by the Schmorl's and Long Ziehl-Neelsen methods. The iron-containing pigment is likely to represent hemosiderin accumulation after retinal micro-hemorrhage or could be indicative of the normal intraretinal iron transport and turnover.

  17. Retinal pigment epithelial hamartoma--unusual manifestations.

    PubMed Central

    Rosenberg, P. R.; Walsh, J. B.

    1984-01-01

    Hamartoma of the retinal pigment epithelium is an uncommon tumour of young adults. We have seen 2 patients with this clinical diagnosis, both with unusual manifestations. In one patient growth of the tumour was observed over a 5-year period. In the second patient arterial-arterial anastomoses were detected at a site distal to the tumour. Images PMID:6722077

  18. BRIEF COMMUNICATIONS: Picosecond spectroscopy of pyrrol pigments

    NASA Astrophysics Data System (ADS)

    Lippitsch, M. E.; Leitner, A.; Riegler, M.; Aussenegg, F. R.

    1982-05-01

    Picosecond fluorescence and absorption spectroscopy methods were used to study pyrromethenone, pyrromethene, and biliverdin. These methods made it possible to determine some details of the kinetics of various relaxation mechanisms. The results obtained provided a better understanding of the biological action of pyrrol pigments.

  19. The 503nm pigment of Escherichia coli

    PubMed Central

    Kamitakahara, Joyce R.; Polglase, W. J.

    1970-01-01

    The yield of cell protein was one-third less for streptomycin-dependent Escherichia coli B than for the wild-type parent strain when both were grown aerobically on a medium with limiting glucose, but anaerobically the yield of protein was similar for both strains. The transient pigment absorbing at 503nm that is known to be present in E. coli and other organisms was not detectable in streptomycin-dependent mutants nor in a non-dependent (energy-deficient) revertant. When wild-type E. coli B was grown on limiting glucose–salts medium containing 2,4 dinitrophenol, the yield of cell protein was decreased and formation of the 503nm pigment was inhibited. Fumarase, aconitase and glucose 6-phosphate dehydrogenase were de-repressed in E. coli B cells grown with excess of glucose in a medium containing 2,4-dinitrophenol. In air-oxidized, wild-type E. coli B cells, the 503nm pigment appeared before reduced cytochromes when gluconate was the substrate but failed to appear when succinate was the substrate. The results provide evidence for a role of the 503nm pigment in aerobic energy metabolism, possibly as an electron acceptor from NADPH. PMID:4395501

  20. "Dry-column" chromatography of plant pigments

    NASA Technical Reports Server (NTRS)

    Woeller, F. H.; Lehwalt, M. F.; Oyama, V. I.

    1973-01-01

    Separation of plant pigments which can be accomplished on thin-layer silica plates with mixture of petroleum ether, halocarbon, acetone, and polar solvent can be readily translated into dry-column technique that yields reproducible chromatograms after elution in fashion of liquid chromatography with fluorimeter as detector. Best solvent system was found to be mixture of petroleum ether, dichloromethane, acetone, and ethyl acetate.

  1. Pigment patterns in adult fish result from superimposition of two largely independent pigmentation mechanisms.

    PubMed

    Ceinos, Rosa M; Guillot, Raúl; Kelsh, Robert N; Cerdá-Reverter, José M; Rotllant, Josep

    2015-03-01

    Dorso-ventral pigment pattern differences are the most widespread pigmentary adaptations in vertebrates. In mammals, this pattern is controlled by regulating melanin chemistry in melanocytes using a protein, agouti-signalling peptide (ASIP). In fish, studies of pigment patterning have focused on stripe formation, identifying a core striping mechanism dependent upon interactions between different pigment cell types. In contrast, mechanisms driving the dorso-ventral countershading pattern have been overlooked. Here, we demonstrate that, in fact, zebrafish utilize two distinct adult pigment patterning mechanisms - an ancient dorso-ventral patterning mechanism, and a more recent striping mechanism based on cell-cell interactions; remarkably, the dorso-ventral patterning mechanism also utilizes ASIP. These two mechanisms function largely independently, with resultant patterns superimposed to give the full pattern.

  2. Rethinking the History of Artists' Pigments Through Chemical Analysis

    NASA Astrophysics Data System (ADS)

    Berrie, Barbara H.

    2012-07-01

    Following a brief overview of the history of analysis of artists' pigments, I discuss the illustrative example of lead-tin yellow. Recent advances in our knowledge of artists' use of red lakes, glassy pigments, and metallic pigments in works of cultural heritage, particularly European paintings, as determined from chemical analyses are described.

  3. The determination and optimization of (rutile) pigment particle size distributions

    NASA Technical Reports Server (NTRS)

    Richards, L. W.

    1972-01-01

    A light scattering particle size test which can be used with materials having a broad particle size distribution is described. This test is useful for pigments. The relation between the particle size distribution of a rutile pigment and its optical performance in a gray tint test at low pigment concentration is calculated and compared with experimental data.

  4. The Eyes Have It: Regulatory and Structural Changes Both Underlie Cichlid Visual Pigment Diversity

    PubMed Central

    Marshall, N. Justin; Cronin, Thomas W.; Seehausen, Ole; Carleton, Karen L.

    2009-01-01

    A major goal of evolutionary biology is to unravel the molecular genetic mechanisms that underlie functional diversification and adaptation. We investigated how changes in gene regulation and coding sequence contribute to sensory diversification in two replicate radiations of cichlid fishes. In the clear waters of Lake Malawi, differential opsin expression generates diverse visual systems, with sensitivities extending from the ultraviolet to the red regions of the spectrum. These sensitivities fall into three distinct clusters and are correlated with foraging habits. In the turbid waters of Lake Victoria, visual sensitivity is constrained to longer wavelengths, and opsin expression is correlated with ambient light. In addition to regulatory changes, we found that the opsins coding for the shortest- and longest-wavelength visual pigments have elevated numbers of potentially functional substitutions. Thus, we present a model of sensory evolution in which both molecular genetic mechanisms work in concert. Changes in gene expression generate large shifts in visual pigment sensitivity across the collective opsin spectral range, but changes in coding sequence appear to fine-tune visual pigment sensitivity at the short- and long-wavelength ends of this range, where differential opsin expression can no longer extend visual pigment sensitivity. PMID:20027211

  5. Detrimental effects of carotenoid pigments: the dark side of bright coloration

    NASA Astrophysics Data System (ADS)

    Huggins, Kristal A.; Navara, Kristen J.; Mendonça, Mary T.; Hill, Geoffrey E.

    2010-07-01

    Carotenoid pigments produce yellow, orange, and red integumentary color displays that can serve as reliable signals of health and condition. In many birds and fish, individuals gain competitive or mating advantages by ingesting and utilizing large quantities of carotenoid pigments. Carotenoid pigments serve as antioxidants, performing important functions as free-radical scavengers. The beneficial effects of carotenoid pigments are well documented, but rarely have researchers considered potential detrimental effects of high-level accumulation of carotenoids. We maintained American goldfinches ( Carduelis tristis) on high- or low-carotenoid diets through molt and tested for damage to the liver and skeletal muscle. High intake of carotenoids had no measurable effect on liver enzymes but caused an increase in creatine kinase, an indicator of skeletal muscle breakdown, and a reduction in vertical flight performance, a measure of skeletal muscle integrity. The detrimental effects of high-level carotenoid accumulation were approximately equivalent to the negative effects of removing carotenoids from the diet. The adverse effects observed in this study have important implications for theories of the function and evolution of colorful plumage.

  6. The eyes have it: regulatory and structural changes both underlie cichlid visual pigment diversity.

    PubMed

    Hofmann, Christopher M; O'Quin, Kelly E; Marshall, N Justin; Cronin, Thomas W; Seehausen, Ole; Carleton, Karen L

    2009-12-01

    A major goal of evolutionary biology is to unravel the molecular genetic mechanisms that underlie functional diversification and adaptation. We investigated how changes in gene regulation and coding sequence contribute to sensory diversification in two replicate radiations of cichlid fishes. In the clear waters of Lake Malawi, differential opsin expression generates diverse visual systems, with sensitivities extending from the ultraviolet to the red regions of the spectrum. These sensitivities fall into three distinct clusters and are correlated with foraging habits. In the turbid waters of Lake Victoria, visual sensitivity is constrained to longer wavelengths, and opsin expression is correlated with ambient light. In addition to regulatory changes, we found that the opsins coding for the shortest- and longest-wavelength visual pigments have elevated numbers of potentially functional substitutions. Thus, we present a model of sensory evolution in which both molecular genetic mechanisms work in concert. Changes in gene expression generate large shifts in visual pigment sensitivity across the collective opsin spectral range, but changes in coding sequence appear to fine-tune visual pigment sensitivity at the short- and long-wavelength ends of this range, where differential opsin expression can no longer extend visual pigment sensitivity.

  7. How parrots see their colours: novelty in the visual pigments of Platycercus elegans.

    PubMed

    Knott, Ben; Davies, Wayne I L; Carvalho, Livia S; Berg, Mathew L; Buchanan, Katherine L; Bowmaker, James K; Bennett, Andrew T D; Hunt, David M

    2013-12-01

    Intraspecific differences in retinal physiology have been demonstrated in several vertebrate taxa and are often subject to adaptive evolution. Nonetheless, such differences are currently unknown in birds, despite variations in habitat, behaviour and visual stimuli that might influence spectral sensitivity. The parrot Platycercus elegans is a species complex with extreme plumage colour differences between (and sometimes within) subspecies, making it an ideal candidate for intraspecific differences in spectral sensitivity. Here, the visual pigments of P. elegans were fully characterised through molecular sequencing of five visual opsin genes and measurement of their absorbance spectra using microspectrophotometry. Three of the genes, LWS, SW1 and SWS2, encode for proteins similar to those found in other birds; however, both the RH1 and RH2 pigments had polypeptides with carboxyl termini of different lengths and unusual properties that are unknown previously for any vertebrate visual pigment. Specifically, multiple RH2 transcripts and protein variants (short, medium and long) were identified for the first time that are generated by alternative splicing of downstream coding and non-coding exons. Our work provides the first complete characterisation of the visual pigments of a parrot, perhaps the most colourful order of birds, and moreover suggests more variability in avian eyes than hitherto considered.

  8. The spectrum of pigmented purpuric dermatosis and mycosis fungoides: atypical T-cell dyscrasia.

    PubMed

    Ladrigan, Manasi Kadam; Poligone, Brian

    2014-12-01

    We report the case of a healthy 17-year-old adolescent boy with an unremarkable medical history who presented with an asymptomatic fixed rash on the abdomen, buttocks, and legs. The rash initially developed in a small area on the right leg 2 years prior and had progressed slowly. Prior biopsies were consistent with pigmented purpura. Clinical examination revealed multiple annular purpuric patches on the abdomen, buttocks, and legs covering approximately 20% of the body surface area without lymphadenopathy or hepatosplenomegaly. Additional biopsies demonstrated changes consistent with mycosis fungoides (MF). T-cell receptor g gene rearrangements demonstrated clonality. The patient was diagnosed with stage IB MF of the pigmented purpura-like variant. The patient responded well to psoralen plus UVA therapy. It has been proposed that pigmented purpuric dermatosis (PPD) is a form of cutaneous T-cell lymphoid dyscrasia and that T-cell gene rearrangement studies should be obtained for prognostic evaluation in patients with widespread disease. In our patient, the clinical appearance of the lesions, pathologic findings, and gene rearrangement studies led to the diagnosis of MF. Until the potential for evolution of PPD to malignant disease is better understood, further evaluation of MF in patients with an unusual presentation of pigmented purpura is warranted.

  9. Origin of adult-type pigment cells forming the asymmetric pigment pattern, in Japanese flounder (Paralichthys olivaceus).

    PubMed

    Yamada, Toshiyuki; Okauchi, Masanori; Araki, Kazuo

    2010-12-01

    The flatfish-specific asymmetric pigment pattern depends on the asymmetric appearance of adult-type pigment cells after the late metamorphic stages. To understand the mechanism enabling the formation of this asymmetric pattern, we investigated the behavior of pigment cell latent precursors in postembryonic Japanese flounder, Paralichthys olivaceus, by analysis of the expression patterns of pigment lineage markers (colony stimulating factor 1 receptor, dopachrome tautomerase, kit) and the DiI (DiO) labeling test for latent precursors. We found that, throughout the larval stages, pigment cell latent precursors were predominantly localized along the dorsal and ventral margins of the flank symmetrically and migrated continuously from these regions to the lateral sides symmetrically, and after late metamorphic stages these precursors differentiated into adult-type pigment cells on the lateral side asymmetrically. We conclude that adult-type pigment cells that form the asymmetric pigment pattern are continuously derived from the dorsal and ventral margins of the flank during larval development.

  10. Dimerization of visual pigments in vivo

    PubMed Central

    Zhang, Tao; Cao, Li-Hui; Kumar, Sandeep; Enemchukwu, Nduka O.; Zhang, Ning; Lambert, Alyssia; Zhao, Xuchen; Jones, Alex; Wang, Shixian; Dennis, Emily M.; Fnu, Amrita; Ham, Sam; Rainier, Jon; Yau, King-Wai; Fu, Yingbin

    2016-01-01

    It is a deeply engrained notion that the visual pigment rhodopsin signals light as a monomer, even though many G protein-coupled receptors are now known to exist and function as dimers. Nonetheless, recent studies (albeit all in vitro) have suggested that rhodopsin and its chromophore-free apoprotein, R-opsin, may indeed exist as a homodimer in rod disk membranes. Given the overwhelmingly strong historical context, the crucial remaining question, therefore, is whether pigment dimerization truly exists naturally and what function this dimerization may serve. We addressed this question in vivo with a unique mouse line (S-opsin+Lrat−/−) expressing, transgenically, short-wavelength–sensitive cone opsin (S-opsin) in rods and also lacking chromophore to exploit the fact that cone opsins, but not R-opsin, require chromophore for proper folding and trafficking to the photoreceptor’s outer segment. In R-opsin’s absence, S-opsin in these transgenic rods without chromophore was mislocalized; in R-opsin’s presence, however, S-opsin trafficked normally to the rod outer segment and produced functional S-pigment upon subsequent chromophore restoration. Introducing a competing R-opsin transmembrane helix H1 or helix H8 peptide, but not helix H4 or helix H5 peptide, into these transgenic rods caused mislocalization of R-opsin and S-opsin to the perinuclear endoplasmic reticulum. Importantly, a similar peptide-competition effect was observed even in WT rods. Our work provides convincing evidence for visual pigment dimerization in vivo under physiological conditions and for its role in pigment maturation and targeting. Our work raises new questions regarding a potential mechanistic role of dimerization in rhodopsin signaling. PMID:27462111

  11. Patchwork Assembly of nag-Like Nitroarene Dioxygenase Genes and the 3-Chlorocatechol Degradation Cluster for Evolution of the 2-Chloronitrobenzene Catabolism Pathway in Pseudomonas stutzeri ZWLR2-1▿

    PubMed Central

    Liu, Hong; Wang, Shu-Jun; Zhang, Jun-Jie; Dai, Hui; Tang, Huiru; Zhou, Ning-Yi

    2011-01-01

    Pseudomonas stutzeri ZWLR2-1 utilizes 2-chloronitrobenzene (2CNB) as a sole source of carbon, nitrogen, and energy. To identify genes involved in this pathway, a 16.2-kb DNA fragment containing putative 2CNB dioxygenase genes was cloned and sequenced. Of the products from the 19 open reading frames that resulted from this fragment, CnbAc and CnbAd exhibited striking identities to the respective α and β subunits of the Nag-like ring-hydroxylating dioxygenases involved in the metabolism of nitrotoluene, nitrobenzene, and naphthalene. The encoding genes were also flanked by two copies of insertion sequence IS6100. CnbAa and CnbAb are similar to the ferredoxin reductase and ferredoxin for anthranilate 1,2-dioxygenase from Burkholderia cepacia DBO1. Escherichia coli cells expressing cnbAaAbAcAd converted 2CNB to 3-chlorocatechol with concomitant nitrite release. Cell extracts of E. coli/pCNBC exhibited chlorocatechol 1,2-dioxygenase activity. The cnbCDEF gene cluster, homologous to a 3-chlorocatechol degradation cluster in Sphingomonas sp. strain TFD44, probably contains all of the genes necessary for the conversion of 3-chlorocatechol to 3-oxoadipate. The patchwork-like structure of this catabolic cluster suggests that the cnb cluster for 2CNB degradation evolved by recruiting two catabolic clusters encoding a nitroarene dioxygenase and a chlorocatechol degradation pathway. This provides another example to help elucidate the bacterial evolution of catabolic pathways in response to xenobiotic chemicals. PMID:21602392

  12. Aspartate Decarboxylase is Required for a Normal Pupa Pigmentation Pattern in the Silkworm, Bombyx mori

    PubMed Central

    Dai, Fangyin; Qiao, Liang; Cao, Cun; Liu, Xiaofan; Tong, Xiaoling; He, Songzhen; Hu, Hai; Zhang, Li; Wu, Songyuan; Tan, Duan; Xiang, Zhonghuai; Lu, Cheng

    2015-01-01

    The pigmentation pattern of Lepidoptera varies greatly in different development stages. To date, the effects of key genes in the melanin metabolism pathway on larval and adult body color are distinct, yet the effects on pupal pigmentation remains unclear. In the silkworm, Bombyx mori, the black pupa (bp) mutant is only specifically melanized at the pupal stage. Using positional cloning, we found that a mutation in the Aspartate decarboxylase gene (BmADC) is causative in the bp mutant. In the bp mutant, a SINE-like transposon with a length of 493 bp was detected ~2.2 kb upstream of the transcriptional start site of BmADC. This insertion causes a sharp reduction in BmADC transcript levels in bp mutants, leading to deficiency of β-alanine and N-β-alanyl dopamine (NBAD), but accumulation of dopamine. Following injection of β-alanine into bp mutants, the color pattern was reverted that of the wild-type silkworms. Additionally, melanic pupae resulting from knock-down of BmADC in the wild-type strain were obtained. These findings show that BmADC plays a crucial role in melanin metabolism and in the pigmentation pattern of the silkworm pupal stage. Finally, this study contributes to a better understanding of pupa pigmentation patterns in Lepidoptera. PMID:26077025

  13. Golden Pigment Production and Virulence Gene Expression Are Affected by Metabolisms in Staphylococcus aureus▿ †

    PubMed Central

    Lan, Lefu; Cheng, Alice; Dunman, Paul M.; Missiakas, Dominique; He, Chuan

    2010-01-01

    The pathogenesis of staphylococcal infections is multifactorial. Golden pigment is an eponymous feature of the human pathogen Staphylococcus aureus that shields the microbe from oxidation-based clearance, an innate host immune response to infection. Here, we screened a collection of S. aureus transposon mutants for pigment production variants. A total of 15 previously unidentified genes were discovered. Notably, disrupting metabolic pathways such as the tricarboxylic acid cycle, purine biosynthesis, and oxidative phosphorylation yields mutants with enhanced pigmentation. The dramatic effect on pigment production seems to correlate with altered expression of virulence determinants. Microarray analysis further indicates that purine biosynthesis impacts the expression of ∼400 genes involved in a broad spectrum of functions including virulence. The purine biosynthesis mutant and oxidative phosphorylation mutant strains exhibit significantly attenuated virulence in a murine abscess model of infection. Inhibition of purine biosynthesis with a known small-molecule inhibitor results in altered virulence gene expression and virulence attenuation during infection. Taken together, these results suggest an intimate link between metabolic processes and virulence gene expression in S. aureus. This study also establishes the importance of purine biosynthesis and oxidative phosphorylation for in vivo survival. PMID:20400547

  14. Aspartate Decarboxylase is Required for a Normal Pupa Pigmentation Pattern in the Silkworm, Bombyx mori.

    PubMed

    Dai, Fangyin; Qiao, Liang; Cao, Cun; Liu, Xiaofan; Tong, Xiaoling; He, Songzhen; Hu, Hai; Zhang, Li; Wu, Songyuan; Tan, Duan; Xiang, Zhonghuai; Lu, Cheng

    2015-06-16

    The pigmentation pattern of Lepidoptera varies greatly in different development stages. To date, the effects of key genes in the melanin metabolism pathway on larval and adult body color are distinct, yet the effects on pupal pigmentation remains unclear. In the silkworm, Bombyx mori, the black pupa (bp) mutant is only specifically melanized at the pupal stage. Using positional cloning, we found that a mutation in the Aspartate decarboxylase gene (BmADC) is causative in the bp mutant. In the bp mutant, a SINE-like transposon with a length of 493 bp was detected ~2.2 kb upstream of the transcriptional start site of BmADC. This insertion causes a sharp reduction in BmADC transcript levels in bp mutants, leading to deficiency of β-alanine and N-β-alanyl dopamine (NBAD), but accumulation of dopamine. Following injection of β-alanine into bp mutants, the color pattern was reverted that of the wild-type silkworms. Additionally, melanic pupae resulting from knock-down of BmADC in the wild-type strain were obtained. These findings show that BmADC plays a crucial role in melanin metabolism and in the pigmentation pattern of the silkworm pupal stage. Finally, this study contributes to a better understanding of pupa pigmentation patterns in Lepidoptera.

  15. Central posterior capsule pigmentation in a patient with pigment dispersion and previous ocular trauma: a case report.

    PubMed

    Al-Mezaine, Hani S

    2010-01-01

    We report a 55-year-old man with unusually dense, unilateral central posterior capsule pigmentation associated with the characteristic clinical features of pigment dispersion syndrome, including a Krukenberg's spindle and dense trabecular pigmentation in both eyes. A history of an old blunt ocular trauma probably caused separation of the anterior hyaloid from the back of the lens, thereby creating an avenue by which pigment could reach the potential space of Berger's from the posterior chamber.

  16. Challenges of identifying eczema in darkly pigmented skin.

    PubMed

    Myers, Joan

    2015-07-01

    There is a paucity of information about the difference in the presentation of eczema in darkly pigmented skin compared to children with fair or white skin. This article describes the possible challenges of diagnosing eczema in children with darkly pigmented skin. The physiological difference in darkly pigmented skin compared with fair or white skin is explored, and how eczema may be manifested and identified in darkly pigmented skin. The author uses the term darkly pigmented skin to describe children of black Caribbean, African or Asian descent.

  17. Mapping of Photosynthetic Pigments in Spanish Reservoirs

    NASA Astrophysics Data System (ADS)

    Peña-Martinez, R.; Domínguez-Gómez, J.-A.; de Hoyos, C.; Ruiz-Verdú, A.

    2004-05-01

    We present the preliminary results of the first stage of the project AO-594, which comprises the development and calibration of algorithms for photosynthetic pigment mapping in Spanish reservoirs. In the years 2001-2002, an extensive field campaign was made in 36 reservoirs and lakes in order to obtain a database of Rrs spectra (400-1000 nm), photosynthetic pigments concentration and phytoplankton composition. The sampled water bodies cover a wide range of environmental conditions, trophic levels and phytoplankton communities. As a first approach in algorithm development, we have explored the relationships between ratios of MERIS bands and pigment concentrations through simple linear regression analysis. The bands have been selected based on the spectral properties of each pigment and a peak analysis of the Rrs spectra. For chlorophyll a, we have found a very good linear relationship (R2 =0.919) using the ratio between bands 9 and 7. Similar results are found using band 8 instead of 7. In any case, the model derived for the whole range of concentrations (0-500 mg m3 ) fails for low values (<15 mg m-3 ). Possible solutions include the use of - non-linear models or the use of two different models depending on the ratio values. For cyanobacteria detection, the ratio between bands 9 and 6 (the later centred at 620 nm) shows a good correlation (R2 =0.723) with phycocyanin concentration measured fluorometrically, and better (R2 =0.945) with zeaxanthin measured using HPLC. The correlation of other indicator pigments with MERIS band ratios is less strong, but is still possible to develop algorithms accurate enough for bloom monitoring. We also discuss the problems found with the L2 MERIS reflectance imagery that we have tried to use for model calibration. We present the results of the study carried on six reservoirs in northeastern Spain. In a date coincident with a MERIS image (June 19th, 2003) we have collected pigment concentration and reflectance data measured from a

  18. Transcriptome analysis reveals novel patterning and pigmentation genes underlying Heliconius butterfly wing pattern variation

    PubMed Central

    2012-01-01

    Background Heliconius butterfly wing pattern diversity offers a unique opportunity to investigate how natural genetic variation can drive the evolution of complex adaptive phenotypes. Positional cloning and candidate gene studies have identified a handful of regulatory and pigmentation genes implicated in Heliconius wing pattern variation, but little is known about the greater developmental networks within which these genes interact to pattern a wing. Here we took a large-scale transcriptomic approach to identify the network of genes involved in Heliconius wing pattern development and variation. This included applying over 140 transcriptome microarrays to assay gene expression in dissected wing pattern elements across a range of developmental stages and wing pattern morphs of Heliconius erato. Results We identified a number of putative early prepattern genes with color-pattern related expression domains. We also identified 51 genes differentially expressed in association with natural color pattern variation. Of these, the previously identified color pattern “switch gene” optix was recovered as the first transcript to show color-specific differential expression. Most differentially expressed genes were transcribed late in pupal development and have roles in cuticle formation or pigment synthesis. These include previously undescribed transporter genes associated with ommochrome pigmentation. Furthermore, we observed upregulation of melanin-repressing genes such as ebony and Dat1 in non-melanic patterns. Conclusions This study identifies many new genes implicated in butterfly wing pattern development and provides a glimpse into the number and types of genes affected by variation in genes that drive color pattern evolution. PMID:22747837

  19. Pigmented Pindborg tumor of the maxilla: A case report

    PubMed Central

    Priya, Subashchandrabose; Madanagopaal, Lakshmikanth Ramiah; Sarada, Venkaterwaran

    2016-01-01

    The calcifying epithelial odontogenic tumor (CEOT), also known as the Pindborg tumor, is a benign locally invasive neoplasm. Common variants of CEOT include noncalcifying, Langerhans cell, bone and cementum forming and clear cell, which have a prognostic significance. Pigmented variants are known to occur in other odontogenic tumors. However, a definitive pigmented variant of CEOT has not been reported in literature so far. Here, we report the first case of pigmented Pindborg tumor arising from the maxilla in a young female. The pigment was demonstrated as melanin by staining and confirmed by immunohistochemistry. The pigmented variant of CEOT did not recur within 18 months postsurgery. Our report indicates that it is essential to recognize the pigmented variant. We discuss the common variants of CEOT and potential histogenesis of the pigmented variant. Further studies are required to reveal the histogenesis of melanocytes and their pathological significance in the odontogenic tumors. PMID:27721633

  20. FRUIT AND VEGETABLE PIGMENTS AS INDICATORS.

    PubMed

    Pratt, O B; Swartout, H O

    1930-05-09

    (1) Solutions of many fruit pigments act as indicators. (2) These solutions are easily prepared and stable, and the pH range of their color changes is in most cases conveniently near the neutral point (3) As liquid indicators they can be used in titrating acids, but not bases (4)Their greatest usefulness depends upon the fact that very satisfactory test papers can be made with them in a simple and inexpensive way.

  1. Melanocyte pigmentation inversely correlates with MCP-1 production and angiogenesis-inducing potential

    PubMed Central

    Adini, Irit; Adini, Avner; Bazinet, Lauren; Watnick, Randolph S.; Bielenberg, Diane R.; D’Amato, Robert J.

    2015-01-01

    The incidence of certain angiogenesis-dependent diseases is higher in Caucasians than in African Americans. Angiogenesis is amplified in wound healing and cornea models in albino C57 mice compared with black C57 mice. Moreover, mouse and human melanocytes with low pigmentation stimulate endothelial cell (EC) proliferation and migration in vitro more than melanocytes with high pigmentation. This effect is due, in part, to the secretion of an angiogenic protein called fibromodulin (FMOD) from lowly pigmented melanocytes. Herein, we expand upon the mechanism contributing to increased angiogenesis in lighter skin and report that monocyte chemotactic protein-1 (MCP-1) is secreted by nonpigmented mouse melanocytes by 5- to 10-fold more than pigmented melanocytes. MCP-1 protein stimulates EC proliferation and migration in vitro and angiogenesis in vivo. Mechanistic studies determine that FMOD is upstream of MCP-1 and promotes its secretion from both melanocytes and activated ECs via stimulation of NF-κB activity. Mice injected with FMOD-neutralizing antibodies show 2.3-fold decreased levels of circulating MCP-1. Human studies confirmed that, on average, Caucasians have 2-fold higher serum levels of MCP-1 than African Americans. Taken together, this study implicates the FMOD/MCP-1 pathway in the regulation of angiogenesis by local melanocytes and suggests that melanogenic activity may protect against aberrant angiogenic diseases.—Adini, I., Adini, A., Bazinet, L., Watnick, R. S., Bielenberg, D. R., and D’Amato, R. J. Melanocyte pigmentation inversely correlates with MCP-1 production and angiogenesis-inducing potential. PMID:25406462

  2. Complex patterns of cis-regulatory polymorphisms in ebony underlie standing pigmentation variation in Drosophila melanogaster.

    PubMed

    Miyagi, Ryutaro; Akiyama, Noriyoshi; Osada, Naoki; Takahashi, Aya

    2015-12-01

    Pigmentation traits in adult Drosophila melanogaster were used in this study to investigate how phenotypic variations in continuous ecological traits can be maintained in a natural population. First, pigmentation variation in the adult female was measured at seven different body positions in 20 strains from the Drosophila melanogaster Genetic Reference Panel (DGRP) originating from a natural population in North Carolina. Next, to assess the contributions of cis-regulatory polymorphisms of the genes involved in the melanin biosynthesis pathway, allele-specific expression levels of four genes were quantified by amplicon sequencing using a 454 GS Junior. Among those genes, ebony was significantly associated with pigmentation intensity of the thoracic segment. Detailed sequence analysis of the gene regulatory regions of this gene indicated that many different functional cis-regulatory alleles are segregating in the population and that variations outside the core enhancer element could potentially play important roles in the regulation of gene expression. In addition, a slight enrichment of distantly associated SNP pairs was observed in the ~10 kb cis-regulatory region of ebony, which suggested the presence of interacting elements scattered across the region. In contrast, sequence analysis in the core cis-regulatory region of tan indicated that SNPs within the region are significantly associated with allele-specific expression level of this gene. Collectively, the data suggest that the underlying genetic differences in the cis-regulatory regions that control intraspecific pigmentation variation can be more complex than those of interspecific pigmentation trait differences, where causal genetic changes are typically confined to modular enhancer elements.

  3. Single amino acid substitution in homogentisate 1,2-dioxygenase is responsible for pigmentation in a subset of Burkholderia cepacia complex isolates

    PubMed Central

    Gonyar, Laura A.; Fankhauser, Sarah C.; Goldberg, Joanna B.

    2015-01-01

    Summary The Burkholderia cepacia complex (Bcc) is a group of Gram-negative bacilli that are ubiquitous in the environment and have emerged over the past 30 years as opportunistic pathogens in immunocompromised populations, specifically individuals with cystic fibrosis (CF) and chronic granulomatous disease. This complex of at least 18 distinct species is phenotypically and genetically diverse. One phenotype observed in a subset of Burkholderia cenocepacia (a prominent Bcc pathogen) isolates is the ability to produce a melanin-like pigment. Melanins have antioxidant properties and have been shown to act as virulence factors allowing pathogens to resist killing by the host immune system. The melanin-like pigment expressed by B. cenocepacia is produced through tyrosine catabolism, specifically through the autoxidation and polymerization of homogentisate. Burkholderia cenocepacia J2315 is a CF clinical isolate that displays a pigmented phenotype when grown under normal laboratory conditions. We examined the amino acid sequences of critical enzymes in the melanin synthesis pathway in pigmented and non-pigmented Bcc isolates, and found that an amino acid substitution of glycine for arginine at amino acid 378 in homogentisate 1,2-dioxygenase correlated with pigment production; we identify this as one mechanism for expression of pigment in Bcc isolates. PMID:25294803

  4. Single amino acid substitution in homogentisate 1,2-dioxygenase is responsible for pigmentation in a subset of Burkholderia cepacia complex isolates.

    PubMed

    Gonyar, Laura A; Fankhauser, Sarah C; Goldberg, Joanna B

    2015-04-01

    The Burkholderia cepacia complex (Bcc) is a group of Gram-negative bacilli that are ubiquitous in the environment and have emerged over the past 30 years as opportunistic pathogens in immunocompromised populations, specifically individuals with cystic fibrosis (CF) and chronic granulomatous disease. This complex of at least 18 distinct species is phenotypically and genetically diverse. One phenotype observed in a subset of Burkholderia cenocepacia (a prominent Bcc pathogen) isolates is the ability to produce a melanin-like pigment. Melanins have antioxidant properties and have been shown to act as virulence factors allowing pathogens to resist killing by the host immune system. The melanin-like pigment expressed by B. cenocepacia is produced through tyrosine catabolism, specifically through the autoxidation and polymerization of homogentisate. Burkholderia cenocepacia J2315 is a CF clinical isolate that displays a pigmented phenotype when grown under normal laboratory conditions. We examined the amino acid sequences of critical enzymes in the melanin synthesis pathway in pigmented and non-pigmented Bcc isolates, and found that an amino acid substitution of glycine for arginine at amino acid 378 in homogentisate 1,2-dioxygenase correlated with pigment production; we identify this as one mechanism for expression of pigment in Bcc isolates.

  5. Optical tomography of pigmented human skin biopsies

    NASA Astrophysics Data System (ADS)

    Riemann, Iris; Fischer, Peter; Kaatz, Martin; Fischer, Tobias W.; Elsner, Peter; Dimitrov, Enrico; Reif, Annette; Konig, Karsten

    2004-07-01

    The novel femtosecond NIR (near infrared) laser based high resolution imaging system DermaInspect was used for non-invasive diagnostics of pigmented skin. The system provides fluorescence and SHG images of high spatial submicron resolution (3D) and 250 ps temporal resolution (4D) based on time resolved single photon counting (TCSPC). Pigmented tissue biopsies from patients with nevi and melanoma have been investigated using the tunable 80 MHz femtosecond laser MaiTai with laser wavelengths in the range of 750 - 850 nm. The autofluorescence patterns of different intratissue cell types and structures were determined. The non-linear induced autofluorescence originates from naturally endogenous fluorophores and protein structures like NAD(P)H, flavins, elastin, collagen, phorphyrins and melanin. In addition to autofluorescence, SHG (second harmonic generation) was used to detect dermal collagen structures. Interestingly, pigmented cells showed intense luminescence signals. Further characterization of tissue components was performed via 4D measurements of the fluorescence lifetime (x, y, z, τ). The novel multiphoton technique offers the possibility of a painless high resolution non invasive diagnostic method (optical biopsy), in particular for the early detection of skin cancer.

  6. Treatment of gingival pigmentation: a case series.

    PubMed

    Deepak, Prasad; Sunil, S; Mishra, R; Sheshadri

    2005-01-01

    A smile expresses a feeling of joy, success, sensuality, affection and courtesy, and reveals self confidence and kindness. The harmony of the smile is determined not only by the shape, the position and the color of the teeth but also by the gingival tissues. Gingival health and appearance are essential components of an attractive smile. Gingival pigmentation results from melanin granules, which are produced by melanoblasts. The degree of pigmentation depends on melanoblastic activity. Although melanin pigmentation of the gingiva is completely benign and does not present a medical problem, complaints of 'black gums' are common particularly in patients having a very high smile line (gummy smile). For depigmentation of gingiva different treatment modalities have been reported like- Bur abrasion, scraping, partial thickness flap, cryotherapy, electrosurgery and laser. In the present case series bur abrasion, scraping, partial thickness flap (epithelial excision) cryotherapy and electrosurgery have been tried for depigmentation, which are simple, effective and yield good results, along with good patient satisfaction. The problems encountered with some of these techniques have also been discussed.

  7. Blackberry pigment (whitlockite) gallstones in uremic patient.

    PubMed

    Cariati, Andrea

    2013-04-01

    Black pigment gallstones represent nearly the 15% of all gallstones and are usually related with the typical "hyperbilirubinbilia" factors as hemolysis, ineffective erythropoiesis, pathologic enterohepatic cycling of unconjugated bilirubin, cirrhosis and with gallbladder mucosa (parietal) factors as adenomyomatosis. During a prospective study on 179 patients who underwent cholecystectomy for gallstone disease a 69-year-old female with predialysis chronic kidney disease was operated for symptomatic gallstone. The removed gallstones were black pigment gallstones, with an irregular (as small blackberry) surface. Analysis of the stones revealed a great amount of whitlockite (Ca Mg)3 (PO4)2. Recent studies on chronic renal failure patients found that chronic uremia is associated with an increased risk of gallstones formation (22%) as it seems in women affected by primary hyperparathyroidism (30%). The presence of calcium phosphate gallstones in these patients have been never described. In conclusion, further studies could be necessary to establish the role of chronic renal failure and of primary and secondary hyperparathyroidism in gallstones formation and, in particular, if dialysis and predialysis patients have an higher risk to develop cholesterol and black pigment gallstones in particular of the "blackberry" (whitlockite) subtype.

  8. Patterns and Drivers of Egg Pigment Intensity and Colour Diversity in the Ocean: A Meta-Analysis of Phylum Echinodermata.

    PubMed

    Montgomery, E M; Hamel, J-F; Mercier, A

    2017-01-01

    supported by the comparatively pale colour of equally large, internally brooded eggs. Secondarily, geographic location drives the evolution of egg colour diversity, presumably through the selection of better-adapted, more costly pigments in response to ecological pressure.

  9. Identification and Molecular Characterization of the Homogentisate Pathway Responsible for Pyomelanin Production, the Major Melanin Constituents in Aeromonas media WS

    PubMed Central

    Wang, He; Qiao, Yunqian; Chai, Baozhong; Qiu, Chenxi; Chen, Xiangdong

    2015-01-01

    The pigmentation of many Aeromonas species has been thought to be due to the production of a L-DOPA (L-3,4-dihydroxyphenylalanine) based melanin. However, in this study we found that although L-DOPA synthesis occurs in the high-melanin-yielding Aeromonas media strain WS, it plays a minor, if any, role in pigmentation. Instead, the pigmentation of A. media strain WS is due to the production of pyomelanin through HGA (homogentisate). Gene products of phhA (encodes phenylalanine hydroxylase), tyrB and aspC (both encode aromatic amino acid aminotransferase), and hppD (encodes 4-hydroxyphenylpyruvate dioxygenase) constitute a linear pathway of converting phenylalanine to HGA and disruption of any one of these genes impairs or blocks pigmentation of A. media strain WS. This HGA biosynthesis pathway is widely distributed in Aeromonas, but HGA is only detectable in the cultures of pigmented Aeromonas species. Heterologous expression of HppD from both pigmented and non-pigmented Aeromonas species in E. coli leads to the production of pyomelanin and thus pigmentation, suggesting that most Aeromonas species have the critical enzymes to produce pyomelanin through HGA. Taken together, we have identified a widely conserved biosynthesis pathway of HGA based pyomelanin in Aeromonas that may be responsible for pigmentation of many Aeromonas species. PMID:25793756

  10. The photochromic effect of bismuth vanadate pigments. Part I: Synthesis, characterization and lightfastness of pigment coatings

    NASA Astrophysics Data System (ADS)

    Tücks, A.; Beck, H. P.

    2005-04-01

    We report on investigations of the photochromic effect of BiVO 4 pigments. Emphasis is placed on an approach widely used in industrial color testing. By means of colorimetry Δ E ab*-values, which measure the perceived color difference, can be calculated from reflectance spectra of non-illuminated and illuminated pigment coatings. Pigments were prepared by either wet-chemical precipitation or solid-state reactions. Depending on the choice of starting compounds, lightfastness was found to vary significantly. Small amounts of impurity phases do not seem to affect photochromism. In contrast, impurities like Fe and Pb cause intense photochromism. The role of Fe is suggested by trace analyses, which (in case of pigments synthesized by precipitation reactions) reveal a correlation between concentration and Δ E ab*. Indications are found that other effects like pigment-lacquer interactions might also be of importance. Difference reflectance spectra turn out to vary in shape depending on the type and concentration of impurities or dopants. For BiVO 4 at least three different mechanisms of photochromism can be assumed.

  11. The photochromic effect of bismuth vanadate pigments. Part I: Synthesis, characterization and lightfastness of pigment coatings

    SciTech Connect

    Tuecks, A.; Beck, H.P. . E-mail: hp.beck@mx.uni-saarland.de

    2005-04-15

    We report on investigations of the photochromic effect of BiVO{sub 4} pigments. Emphasis is placed on an approach widely used in industrial color testing. By means of colorimetry {delta}E{sub ab}*-values, which measure the perceived color difference, can be calculated from reflectance spectra of non-illuminated and illuminated pigment coatings. Pigments were prepared by either wet-chemical precipitation or solid-state reactions. Depending on the choice of starting compounds, lightfastness was found to vary significantly. Small amounts of impurity phases do not seem to affect photochromism. In contrast, impurities like Fe and Pb cause intense photochromism. The role of Fe is suggested by trace analyses, which (in case of pigments synthesized by precipitation reactions) reveal a correlation between concentration and {delta}E{sub ab}*. Indications are found that other effects like pigment-lacquer interactions might also be of importance. Difference reflectance spectra turn out to vary in shape depending on the type and concentration of impurities or dopants. For BiVO{sub 4} at least three different mechanisms of photochromism can be assumed.

  12. Update on the regulation of mammalian melanocyte function and skin pigmentation

    PubMed Central

    Kondo, Taisuke; Hearing, Vincent J

    2011-01-01

    Melanogenesis is the unique process of producing pigmented biopolymers that are sequestered within melanosomes, which provides color to the skin, hair and eyes of animals and, in the case of human skin, also protects the underlying tissues from UV damage. We review the current understanding of melanogenesis, focusing on factors important to the biochemistry of pigment synthesis, the biogenesis of melanosomes, signaling pathways and factors that regulate melanogenesis, intramelanosomal pH, transport and transfer of melanosomes, and pigmentary disorders related to the dysfunction of melanosome-related proteins. Although it has been known for some time that many of the factors that affect melanogenesis are derived from keratinocytes, fibroblasts, endothelial cells, hormones, inflammatory cells and nerves, a number of new factors that are involved in that regulation have recently been reported, such as factors that regulate melanosome pH and ion transport. PMID:21572549

  13. Melanoma induction by ultraviolet A but not ultraviolet B radiation requires melanin pigment.

    PubMed

    Noonan, Frances P; Zaidi, M Raza; Wolnicka-Glubisz, Agnieszka; Anver, Miriam R; Bahn, Jesse; Wielgus, Albert; Cadet, Jean; Douki, Thierry; Mouret, Stephane; Tucker, Margaret A; Popratiloff, Anastas; Merlino, Glenn; De Fabo, Edward C

    2012-06-06

    Malignant melanoma of the skin (CMM) is associated with ultraviolet radiation exposure, but the mechanisms and even the wavelengths responsible are unclear. Here we use a mammalian model to investigate melanoma formed in response to precise spectrally defined ultraviolet wavelengths and biologically relevant doses. We show that melanoma induction by ultraviolet A (320-400 nm) requires the presence of melanin pigment and is associated with oxidative DNA damage within melanocytes. In contrast, ultraviolet B radiation (280-320 nm) initiates melanoma in a pigment-independent manner associated with direct ultraviolet B DNA damage. Thus, we identified two ultraviolet wavelength-dependent pathways for the induction of CMM and describe an unexpected and significant role for melanin within the melanocyte in melanomagenesis.

  14. Characterization of the Mantle Transcriptome of Yesso Scallop (Patinopecten yessoensis): Identification of Genes Potentially Involved in Biomineralization and Pigmentation

    PubMed Central

    Sun, Xiujun; Yang, Aiguo; Wu, Biao; Zhou, Liqing; Liu, Zhihong

    2015-01-01

    The Yesso scallop Patinopecten yessoensis is an economically important marine bivalve species in aquaculture and fishery in Asian countries. However, limited genomic resources are available for this scallop, which hampers investigations into molecular mechanisms underlying their unique biological characteristics, such as shell formation and pigmentation. Mantle is the special tissue of P. yessoensis that secretes biomineralization proteins inducing shell deposition as well as pigmentation on the shells. However, a current deficiency of transcriptome information limits insight into mechanisms of shell formation and pigmentation in this species. In this study, the transcriptome of the mantle of P. yessoensis was deeply sequenced and characterized using Illumina RNA-seq technology. A total of 86,521 unique transcripts are assembled from 55,884,122 reads that passed quality filters, and annotated, using Gene Ontology classification. A total of 259 pathways are identified in the mantle transcriptome, including the calcium signaling and melanogenesis pathways. A total of 237 unigenes that are homologous to 102 reported biomineralization genes are identified, and 121 unigenes that are homologous to 93 known proteins related to melanin biosynthesis are found. Twenty-three annotated unigenes, which are mainly homologous to calmodulin and related proteins, Ca2+/calmodulin-dependent protein kinase, adenylate/guanylate cyclase, and tyrosinase family are potentially involved in both biomineralization and melanin biosynthesis. It is suggested that these genes are probably not limited in function to induce shell deposition by calcium metabolism, but may also be involved in pigmentation of the shells of the scallop. This potentially supports the idea that there might be a link between calcium metabolism and melanin biosynthesis, which was previously found in vertebrates. The findings presented here will notably advance the understanding of the sophisticated processes of shell

  15. Characterization of the mantle transcriptome of yesso scallop (Patinopecten yessoensis): identification of genes potentially involved in biomineralization and pigmentation.

    PubMed

    Sun, Xiujun; Yang, Aiguo; Wu, Biao; Zhou, Liqing; Liu, Zhihong

    2015-01-01

    The Yesso scallop Patinopecten yessoensis is an economically important marine bivalve species in aquaculture and fishery in Asian countries. However, limited genomic resources are available for this scallop, which hampers investigations into molecular mechanisms underlying their unique biological characteristics, such as shell formation and pigmentation. Mantle is the special tissue of P. yessoensis that secretes biomineralization proteins inducing shell deposition as well as pigmentation on the shells. However, a current deficiency of transcriptome information limits insight into mechanisms of shell formation and pigmentation in this species. In this study, the transcriptome of the mantle of P. yessoensis was deeply sequenced and characterized using Illumina RNA-seq technology. A total of 86,521 unique transcripts are assembled from 55,884,122 reads that passed quality filters, and annotated, using Gene Ontology classification. A total of 259 pathways are identified in the mantle transcriptome, including the calcium signaling and melanogenesis pathways. A total of 237 unigenes that are homologous to 102 reported biomineralization genes are identified, and 121 unigenes that are homologous to 93 known proteins related to melanin biosynthesis are found. Twenty-three annotated unigenes, which are mainly homologous to calmodulin and related proteins, Ca2+/calmodulin-dependent protein kinase, adenylate/guanylate cyclase, and tyrosinase family are potentially involved in both biomineralization and melanin biosynthesis. It is suggested that these genes are probably not limited in function to induce shell deposition by calcium metabolism, but may also be involved in pigmentation of the shells of the scallop. This potentially supports the idea that there might be a link between calcium metabolism and melanin biosynthesis, which was previously found in vertebrates. The findings presented here will notably advance the understanding of the sophisticated processes of shell

  16. Identification, characterisation and molecular modelling of two AP endonucleases from base excision repair pathway in sugarcane provide insights on the early evolution of green plants.

    PubMed

    Maira, N; Torres, T M; de Oliveira, A L; de Medeiros, S R B; Agnez-Lima, L F; Lima, J P M S; Scortecci, K C

    2014-05-01

    Unlike bacteria and mammals, plant DNA repair pathways are not well characterised, especially in monocots. The understanding of these processes in the plant cell is of major importance, since they may be directly involved in plant acclimation and adaptation to stressful environments. Hence, two sugarcane ESTs were identified as homologues of AP endonuclease from the base-excision repair pathway: ScARP1 and ScARP3. In order to understand their probable function and evolutionary origin, structural and phylogenetic studies were performed using bioinformatics approaches. The two predicted proteins present a considerable amino acid sequence similarity, and molecular modelling procedures indicate that both are functional, since the main structural motifs remain conserved. However, inspection of the sort signal regions on the full-length cDNAs indicated that these proteins have a distinct organelle target. Furthermore, variances in their promoter cis-element motifs were also found. Although the mRNA expression pattern was similar, there were significant differences in their expression levels. Taken together, these data raise the hypothesis that the ScARP is an example of a probable gene duplication event that occurred before monocotyledon/dicotyledon segregation, followed by a sub-functionalisation event in the Poaceae, leading to new intracellular targeting and different expression levels.

  17. The genetics of skin, hair, and eye color variation and its relevance to forensic pigmentation predictive tests.

    PubMed

    Maroñas, O; Söchtig, J; Ruiz, Y; Phillips, C; Carracedo, Á; Lareu, M V

    2015-01-01

    This review examines the potential application of single nucleotide polymorphism (SNP)-based predictive tests for skin, hair, and eye color to forensic analysis in support of police investigations lacking DNA database matches or eyewitness testimony. Brief descriptions of the biology of melanogenesis and the main genes involved are presented in order to understand the basis of common pigmentation variation in humans. We outline the most recently developed forensically sensitive multiplex tests that can be applied to investigative analyses. The review also describes the biology of the SNPs with the closest associations to, and therefore the best predictors for, common variation in eye, hair, and skin pigmentation. Because pigmentation pathways are complex in their patterns, many of the better-studied human albinism traits provide insight into how pigmentation SNPs interact, control, or modify gene expression and show varying degrees of association with the key genes identified to date. These aspects of SNP action are discussed in an overview of each of the functional groups of pigmentation genes.

  18. Transient ectopic overexpression of agouti-signalling protein 1 (asip1) induces pigment anomalies in flatfish.

    PubMed

    Guillot, Raúl; Ceinos, Rosa Maria; Cal, Rosa; Rotllant, Josep; Cerdá-Reverter, José Miguel

    2012-01-01

    While flatfish in the wild exhibit a pronounced countershading of the dorso-ventral pigment pattern, malpigmentation is commonly observed in reared animals. In fish, the dorso-ventral pigment polarity is achieved because a melanization inhibition factor (MIF) inhibits melanoblast differentiation and encourages iridophore proliferation in the ventrum. A previous work of our group suggested that asip1 is the uncharacterized MIF concerned. In order to further support this hypothesis, we have characterized asip1 mRNAs in both turbot and sole and used deduced peptide alignments to analyze the evolutionary history of the agouti-family of peptides. The putative asip precursors have the characteristics of a secreted protein, displaying a putative hydrophobic signal. Processing of the potential signal peptide produces mature proteins that include an N-terminal region, a basic central domain with a high proportion of lysine residues as well as a proline-rich region that immediately precedes the C-terminal poly-cysteine domain. The expression of asip1 mRNA in the ventral area was significantly higher than in the dorsal region. Similarly, the expression of asip1 within the unpigmented patches in the dorsal skin of pseudoalbino fish was higher than in the pigmented dorsal regions but similar to those levels observed in the ventral skin. In addition, the injection/electroporation of asip1 capped mRNA in both species induced long term dorsal skin paling, suggesting the inhibition of the melanogenic pathways. The data suggest that fish asip1 is involved in the dorsal-ventral pigment patterning in adult fish, where it induces the regulatory asymmetry involved in precursor differentiation into mature chromatophore. Adult dorsal pseudoalbinism seems to be the consequence of the expression of normal developmental pathways in an inaccurate position that results in unbalanced asip1 production levels. This, in turn, generates a ventral-like differentiation environment in dorsal regions.

  19. Transposon Mutagenesis of Mycobacterium marinum Identifies a Locus Linking Pigmentation and Intracellular Survival

    PubMed Central

    Gao, Lian-Yong; Groger, Richard; Cox, Jeffery S.; Beverley, Stephen M.; Lawson, Elise H.; Brown, Eric J.

    2003-01-01

    Pathogenic mycobacteria survive and replicate within host macrophages, but the molecular mechanisms involved in this necessary step in the pathogenesis of infection are not completely understood. Mycobacterium marinum has recently been used as a model for aspects of the pathogenesis of tuberculosis because of its close genetic relationship to Mycobacterium tuberculosis and because of similarities in the pathology and course of infection caused by this organism in its natural hosts, fish and frogs, with tuberculosis in humans. In order to advance the utility of the M. marinum model, we have developed efficient transposon mutagenesis of the organism by using a Drosophila melanogaster mariner-based transposon. To determine the efficiency of transposition, we have analyzed pigmentation mutants from the transposon mutant library. In addition to insertions in four known genes in the pathway of pigment biosynthesis, two insertions in novel genes were identified in our mutant library. One of these is in a putative inhibitor of the carotenoid biosynthesis pathway. The second unexpected insertion is in an intergenic region between two genes homologous to Rv2603c and Rv2604c of M. tuberculosis. In addition to a pigmentation defect, this mutant showed increased susceptibility to singlet oxygen and grew poorly in murine macrophages. Complementation with M. tuberculosis genomic DNA encompassing Rv2603c to Rv2606c corrected the pigmentation and growth defects of the mutant. These data demonstrate the utility of mariner-based transposon mutagenesis of M. marinum and that M. marinum can be used to study the function of M. tuberculosis genes involved in intracellular survival and replication. PMID:12540574

  20. Evolution of Anthocyanin Biosynthesis in Maize Kernels: The Role of Regulatory and Enzymatic Loci

    PubMed Central

    Hanson, M. A.; Gaut, B. S.; Stec, A. O.; Fuerstenberg, S. I.; Goodman, M. M.; Coe, E. H.; Doebley, J. F.

    1996-01-01

    Understanding which genes contribute to evolutionary change and the nature of the alterations in them are fundamental challenges in evolution. We analyzed regulatory and enzymatic genes in the maize anthocyanin pathway as related to the evolution of anthocyanin-pigmented kernels in maize from colorless kernels of its progenitor, teosinte. Genetic tests indicate that teosinte possesses functional alleles at all enzymatic loci. At two regulatory loci, most teosintes possess alleles that encode functional proteins, but ones that are not expressed during kernel development and not capable of activating anthocyanin biosynthesis there. We investigated nucleotide polymorphism at one of the regulatory loci, c1. Several observations suggest that c1 has not evolved in a strictly neutral manner, including an exceptionally low level of polymorphism and a biased representation of haplotypes in maize. Curiously, sequence data show that most of our teosinte samples possess a promoter element necessary for the activation of the anthocyanin pathway during kernel development, although genetic tests indicate that teosinte c1 alleles are not active during kernel development. Our analyses suggest that the evolution of the purple kernels resulted from changes in cis regulatory elements at regulatory loci and not changes in either regulatory protein function nor the enzymatic loci. PMID:8807310

  1. Evolution of the Eye Transcriptome under Constant Darkness in Sinocyclocheilus Cavefish

    PubMed Central

    Meng, Fanwei; Braasch, Ingo; Phillips, Jennifer B.; Lin, Xiwen; Titus, Tom; Zhang, Chunguang; Postlethwait, John H.

    2013-01-01

    In adaptating to perpetual darkness, cave species gradually lose eyes and body pigmentation and evolve alternatives for exploring their environments. Although troglodyte features evolved independently many times in cavefish, we do not yet know whether independent evolution of these characters involves common genetic mechanisms. Surface-dwelling and many cave-dwelling species make the freshwater teleost genus Sinocyclocheilus an excellent model for studying the evolution of adaptations to life in constant darkness. We compared the mature retinal histology of surface and cave species in Sinocyclocheilus and found that adult cavefish showed a reduction in the number and length of photoreceptor cells. To identify genes and genetic pathways that evolved in constant darkness, we used RNA-seq to compare eyes of surface and cave species. De novo transcriptome assemblies were developed for both species, and contigs were annotated with gene ontology. Results from cave-dwelling Sinocyclocheilus revealed reduced transcription of phototransduction and other genes important for retinal function. In contrast to the blind Mexican tetra cavefish Astyanax mexicanus, our results on morphologies and gene expression suggest that evolved retinal reduction in cave-dwelling Sinocyclocheilus occurs in a lens-independent fashion by the reduced proliferation and downregulation of transcriptional factors shown to have direct roles in retinal development and maintenance, including cone-rod homeobox (crx) and Wnt pathway members. These results show that the independent evolution of retinal degeneration in cavefish can occur by different developmental genetic mechanisms. PMID:23612715

  2. Evolution of the eye transcriptome under constant darkness in Sinocyclocheilus cavefish.

    PubMed

    Meng, Fanwei; Braasch, Ingo; Phillips, Jennifer B; Lin, Xiwen; Titus, Tom; Zhang, Chunguang; Postlethwait, John H

    2013-07-01

    In adaptating to perpetual darkness, cave species gradually lose eyes and body pigmentation and evolve alternatives for exploring their environments. Although troglodyte features evolved independently many times in cavefish, we do not yet know whether independent evolution of these characters involves common genetic mechanisms. Surface-dwelling and many cave-dwelling species make the freshwater teleost genus Sinocyclocheilus an excellent model for studying the evolution of adaptations to life in constant darkness. We compared the mature retinal histology of surface and cave species in Sinocyclocheilus and found that adult cavefish showed a reduction in the number and length of photoreceptor cells. To identify genes and genetic pathways that evolved in constant darkness, we used RNA-seq to compare eyes of surface and cave species. De novo transcriptome assemblies were developed for both species, and contigs were annotated with gene ontology. Results from cave-dwelling Sinocyclocheilus revealed reduced transcription of phototransduction and other genes important for retinal function. In contrast to the blind Mexican tetra cavefish Astyanax mexicanus, our results on morphologies and gene expression suggest that evolved retinal reduction in cave-dwelling Sinocyclocheilus occurs in a lens-independent fashion by the reduced proliferation and downregulation of transcriptional factors shown to have direct roles in retinal development and maintenance, including cone-rod homeobox (crx) and Wnt pathway members. These results show that the independent evolution of retinal degeneration in cavefish can occur by different developmental genetic mechanisms.

  3. High-contrast enzymatic immunohistochemistry of pigmented tissues

    PubMed Central

    Duncan, Sara M.; Seigel, Gail M.

    2016-01-01

    Historically, standard enzyme immunohistochemistry has been accomplished with brown (DAB, diaminobenzidine) substrate. This can become problematic in pigmented tissues, such as the retina, where brown pigment of retinal pigmented epithelial (RPE) cells can be easily confounded with brown substrate. Although immunofluorescence detection methods can overcome this challenge, fluorescence may fade over a period of weeks, while enzyme substrates allow for more long-lasting, archival results. In this report, we will describe a high-contrast enzyme immunohistochemistry method ideal for pigmented tissues that utilizes purple (VIP) substrate. We compared brown (DAB) and purple (VIP) substrates in enzyme immunohistochemistry experiments using human retina (paraffin sections) and monkey retinal pigmented epithelial cells (frozen sections), both containing brown pigmented cells. We compared substrates using several primary antibodies against markers that can be detected in the retina, including GFAP, VEGF, CD147 (EMMPRIN), RHO (rhodopsin) and PAX6. Methyl green was used as a counterstain for paraffin sections. A side-by-side comparison between DAB and VIP immunohistochemistry showed excellent contrast between pigmented cells and the purple VIP substrate in both human retinal tissue and monkey pigmented epithelial cells for all of the markers tested. This was a marked improvement over DAB staining in pigmented cells and tissues. For both paraffin sections and frozen sections of pigmented tissues, purple VIP substrate is an excellent alternative to brown DAB substrate and non-permanent immunofluorescence methods. PMID:27660801

  4. GREEN FLUORESCENT PIGMENT ACCUMULATED BY A MUTANT OF CELLVIBRIO GILVUS.

    PubMed

    LOVE, S H; HULCHER, F H

    1964-01-01

    Love, Samuel H. (Bowman Gray School of Medicine, Winston-Salem, N.C.), and Frank H. Hulcher. Green fluorescent pigment accumulated by a mutant of Cellvibrio gilvus. J. Bacteriol. 87:39-45. 1964.-A mutant of Cellvibrio gilvus, designated strain 139A, liberated a green, fluorescent pigment into the surrounding culture medium. A study of the factors which affected the accumulation of this pigment led to the development of a chemically defined medium which supported maximal pigment accumulation in aerated, liquid cultures. d-Glucose, glycine or l-serine, l-phenylalanine, l-proline, and l-lysine comprised the organic components of this medium. The visible absorption spectrum of the pigment showed a maximal band at 400 mmu (pH 7.0). A difference spectrum between reduced and oxidized pigment showed loss of the band at 400 mmu upon oxidation. However, a methanol-extractable, flavinelike compound occurred in the wild strain but not in the mutant. Ferric ions added to the defined medium stimulated growth, with a concomitant reduction of pigment accumulation. Pigment was formed at a maximal rate during the stationary growth phase, and the highest yield was obtained by 18 hr. Organic solvents did not extract the pigment from water solutions. One and sometimes two, compounds absorbing at 400 mmu could be eluted by ion-exchange chromatography on Cellex-P (H(+)), which was used to separate the pigment from other components in the culture supernatants so that the radioactivity of the pigment could be measured. The mutant synthesized C(14)-labeled pigment from d-glucose-U-C(14) and from each of four amino acids (glycine-1-C(14), l-phenylalanine-U-C(14), l-proline-U-C(14), and l-lysine-U-C(14). Delta-Amino-levulenic acid-4-C(14) did not contribute C(14) to the pigment.

  5. Study on the autofluorescence profiles of iris pigment epithelium and retinal pigment epithetlium

    NASA Astrophysics Data System (ADS)

    Xu, Gaixia; Qu, Junle; Chen, Danni; Sun, Yiwen; Zhao, Lingling; Lin, Ziyang; Ding, Zhihua; Niu, Hanben

    2007-05-01

    Transplantation technique of retinal pigment epithelium has been noticeable in recent years and gradually put into clinical practice in treatment of retinal degenerative diseases. Generally, immunological, histochemical, and physical methods are used to study the iris pigment epithelium (IPE) and retinal pigment epithelium (RPE) cells, which need complex sample preparation. In this paper, we provided a simple autofluorescence microscopy to investigate the fresh porcine IPE and RPE cells without any pretreatment. The results showed that the morphology and size of both were similar, round and about 15 μm. The main flourophore in both cells was similar, i.e. lipofuscin. In additional, the autofluorescence spectrum of RPE shifted blue after light-induced damage by laser illuminating. Because it was easier for IPE to be damaged by laser than for RPE, and the power of one scanning operation to get a full image was strong enough to damage IPE sample, we hadn't get any satisfied autofluorescence spectrum of IPE.

  6. Probing S-state advancements and recombination pathways in photosystem II with a global fit program for flash-induced oxygen evolution pattern.

    PubMed

    Pham, Long Vo; Messinger, Johannes

    2016-06-01

    The oxygen-evolving complex (OEC) in photosystem II catalyzes the oxidation of water to molecular oxygen. Four decades ago, measurements of flash-induced oxygen evolution have shown that the OEC steps through oxidation states S(0), S(1), S(2), S(3) and S(4) before O(2) is released and the S(0) state is reformed. The light-induced transitions between these states involve misses and double hits. While it is widely accepted that the miss parameter is S state dependent and may be further modulated by the oxidation state of the acceptor side, the traditional way of analyzing each flash-induced oxygen evolution pattern (FIOP) individually did not allow using enough free parameters to thoroughly test this proposal. Furthermore, this approach does not allow assessing whether the presently known recombination processes in photosystem II fully explain all measured oxygen yields during Si state lifetime measurements. Here we present a global fit program that simultaneously fits all flash-induced oxygen yields of a standard FIOP (2 Hz flash frequency) and of 11-18 FIOPs each obtained while probing the S(0), S(2) and S(3) state lifetimes in spinach thylakoids at neutral pH. This comprehensive data treatment demonstrates the presence of a very slow phase of S(2) decay, in addition to the commonly discussed fast and slow reduction of S(2) by YD and QB(-), respectively. Our data support previous suggestions that the S(0)→S(1) and S(1)→S(2) transitions involve low or no misses, while high misses occur in the S(2)→S(3) or S(3)→S(0) transitions.

  7. Regulatory Genes Controlling Anthocyanin Pigmentation Are Functionally Conserved among Plant Species and Have Distinct Sets of Target Genes.

    PubMed Central

    Quattrocchio, F; Wing, JF; Leppen, H; Mol, J; Koes, RE

    1993-01-01

    In this study, we demonstrate that in petunia at least four regulatory genes (anthocyanin-1 [an1], an2, an4, and an11) control transcription of a subset of structural genes from the anthocyanin pathway by using a combination of RNA gel blot analysis, transcription run-on assays, and transient expression assays. an2- and an11- mutants could be transiently complemented by the maize regulatory genes Leaf color (Lc) or Colorless-1 (C1), respectively, whereas an1- mutants only by Lc and C1 together. In addition, the combination of Lc and C1 induces pigment accumulation in young leaves. This indicates that Lc and C1 are both necessary and sufficient to produce pigmentation in leaf cells. Regulatory pigmentation genes in maize and petunia control different sets of structural genes. The maize Lc and C1 genes expressed in petunia differentially activate the promoters of the chalcone synthase genes chsA and chsJ in the same way that the homologous petunia genes do. This suggests that the regulatory proteins in both species are functionally similar and that the choice of target genes is determined by their promoter sequences. We present an evolutionary model that explains the differences in regulation of pigmentation pathways of maize, petunia, and snapdragon. PMID:12271045

  8. Characterization of Sorolla's gouache pigments by means of spectroscopic techniques

    NASA Astrophysics Data System (ADS)

    Roldán, Clodoaldo; Juanes, David; Ferrazza, Livio; Carballo, Jorgelina

    2016-02-01

    This paper presents the characterization of the Joaquín Sorolla's gouache sketches for the oil on canvas series "Vision of Spain" commissioned by A. M. Huntington to decorate the library of the Hispanic Society of America in New York. The analyses were focused on the identification of the elemental composition of the gouache pigments by means of portable EDXRF spectrometry in a non-destructive mode. Additionally, SEM-EDX and FTIR analyses of a selected set of micro-samples were carried out to identify completely the pigments, the paint technique and the binding media. The obtained results have confirmed the identification of lead and zinc white, vermillion, earth pigments, ochre, zinc yellow, chrome yellow, ultramarine, Prussian blue, chromium based and copper-arsenic based green pigments, bone black and carbon based black pigments, and the use of gum arabic as binding media in the gouache pigments.

  9. Analytical Raman spectroscopic discrimination between yellow pigments of the Renaissance.

    PubMed

    Edwards, Howell G M

    2011-10-01

    The Renaissance represented a major advance in painting techniques, subject matter, artistic style and the use of pigments and pigment mixtures. However, most pigments in general use were still mineral-based as most organic dyes were believed to be fugitive; the historical study of artists' palettes and recipes has assumed importance for the attribution of art works to the Renaissance period. Although the application of diagnostic elemental and molecular spectroscopic techniques play vital and complementary roles in the analysis of art works, elemental techniques alone cannot definitively provide the data needed for pigment identification. The advantages and limitations of Raman spectroscopy for the definitive diagnostic characterisation of yellow pigments that were in use during the Renaissance is demonstrated here in consideration of heavy metal oxides and sulphides; these data will be compared with those obtained from analyses of synthetic yellow pigments that were available during the eighteenth and nineteenth Centuries which could have been used in unrecorded restorations of Renaissance paintings.

  10. Oral pigmented lesions: Clinicopathologic features and review of the literature

    PubMed Central

    da Silva-Jorge, Rogério; Jorge, Jacks; Lopes, Márcio A.; Vargas, Pablo A.

    2012-01-01

    Diagnosis of pigmented lesions of the oral cavity and perioral tissues is challenging. Even though epidemiology may be of some help in orientating the clinician and even though some lesions may confidently be diagnosed on clinical grounds alone, the definitive diagnosis usually requires histopathologic evaluation. Oral pigmentation can be physiological or pathological, and exogenous or endogenous. Color, location, distribution, and duration as well as drugs use, family history, and change in pattern are important for the differential diagnosis. Dark or black pigmented lesions can be focal, multifocal or diffuse macules, including entities such as racial pigmentation, melanotic macule, melanocytic nevus, blue nevus, smoker’s melanosis, oral melanoacanthoma, pigmentation by foreign bodies or induced by drugs, Peutz-Jeghers syndrome, Addison´s disease and oral melanoma. The aim of this review is to present the main oral black lesions contributing to better approach of the patients. Key words:Pigmentation, melanin, oral, diagnosis, management. PMID:22549672

  11. Mapping pigment distribution in mud samples through hyperspectral imaging

    NASA Astrophysics Data System (ADS)

    Mehrübeoglu, Mehrube; Nicula, Cosmina; Trombley, Christopher; Smith, Shane W.; Smith, Dustin K.; Shanks, Elizabeth S.; Zimba, Paul V.

    2015-09-01

    Mud samples collected from bodies of water reveal information about the distribution of microorganisms in the local sediments. Hyperspectral imaging has been investigated as a technology to identify phototropic organisms living on sediments collected from the Texas Coastal Bend area based on their spectral pigment profiles and spatial arrangement. The top pigment profiles identified through high-performance liquid chromatography (HPLC) have been correlated with spectral signatures extracted from the hyperspectral data of mud using fast Fourier transform (FFT). Spatial distributions have also been investigated using 2D hyperspectral image processing. 2D pigment distribution maps have been created based on the correlation with pigment profiles in the FFT domain. Among the tested pigments, the results show match among four out of five pigment distribution trends between HPLC and hyperspectral data analysis. Differences are attributed mainly to the difference between area and volume of scale between the HPLC analysis and area covered by hyperspectral imaging.

  12. Evolution of the tapetum.

    PubMed Central

    Schwab, Ivan R; Yuen, Carlton K; Buyukmihci, Nedim C; Blankenship, Thomas N; Fitzgerald, Paul G

    2002-01-01

    PURPOSE: To review, contrast, and compare current known tapetal mechanisms and review the implications for the evolution of the tapetum. METHODS: Ocular specimens of representative fish in key piscine families, including Acipenseridae, Cyprinidae, Chacidae; the reptilian family Crocodylidae; the mammalian family Felidae; and the Lepidopteran family Sphingidae were reviewed and compared histologically. All known varieties of tapeta were examined and classified and compared to the known cladogram representing the evolution of each specific family. RESULTS: Types of tapeta include tapetum cellulosum, tapetum fibrosum, retinal tapetum, invertebrate pigmented tapetum, and invertebrate thin-film tapetum. All but the invertebrate pigmented tapetum were examined histologically. Review of the evolutionary cladogram and comparison with known tapeta suggest that the tapetum evolved in the Devonian period 345 to 395 million years ago. Tapeta developed independently in at least three separate orders in invertebrates and vertebrates, and yet all have surprisingly similar mechanisms of light reflection, including thin-film interference, diffusely reflecting tapeta, Mie scattering, Rayleigh scattering, and perhaps orthogonal retroreflection. CONCLUSION: Tapeta are found in invertebrates and vertebrates and display different physical mechanisms of reflection. Each tapetum reflects the wavelengths most relevant to the species' ecological niche. With this work, we have hypothesized that the tapetum evolved independently in both invertebrates and vertebrates as early as the Devonian period and coincided with an explosion of life forms. PMID:12545693

  13. Chlorpromazine-induced skin pigmentation with corneal and lens opacities.

    PubMed

    Huff, Laura S; Prado, Renata; Pederson, Jon F; Dunnick, Cory A; Lucas, Lisa M

    2014-05-01

    Chlorpromazine is known to cause abnormal oculocutaneous pigmentation in sun-exposed areas. We present the case of a psychiatric patient who developed blue-gray pigmentation of the skin as well as corneal and lens opacities following 7 years of chlorpromazine treatment. Ten months after discontinuation of chlorpromazine, the skin discoloration and anterior lens deposits showed partial improvement, but the corneal deposits remained unchanged. A review of the literature on the reversibility of chlorpromazine-induced abnormal oculocutaneous pigmentation also is provided.

  14. BASIS FOR ENHANCED BARRIER FUNCTION OF PIGMENTED SKIN

    PubMed Central

    Man, Mao-Qiang; Lin, Tzu-Kai; Santiago, Juan Luis; Celli, Anna; Zhong, Lily; Huang, Zhi-Ming; Roelandt, Truus; Hupe, Melanie; Sundberg, John P.; Silva, Kathleen A.; Crumrine, Debra; Martin-Ezquerra, Gemma; Trullas, Carles; Sun, Richard; Wakefield, Joan S.; Wei, Maria L.; Feingold, Kenneth R.; Mauro, Theodora M.; Elias, Peter M.

    2014-01-01

    Humans with darkly-pigmented skin display superior permeability barrier function in comparison to humans with lightly-pigmented skin. The reduced pH of the stratum corneum (SC) of darkly-pigmented skin could account for enhanced function, because acidifying lightly-pigmented human SC resets barrier function to darkly-pigmented levels. In SKH1 (non-pigmented) vs. SKH2/J (pigmented) hairless mice, we evaluated how a pigment-dependent reduction in pH could influence epidermal barrier function. Permeability barrier homeostasis is enhanced in SKH2/J vs. SKH1 mice, correlating with a reduced pH in the lower SC that co-localizes with the extrusion of melanin granules. Darkly-pigmented human epidermis also shows substantial melanin extrusion in the outer epidermis. Both acute barrier disruption and topical basic pH challenges accelerate re-acidification of SKH2/J (but not SKH1) SC, while inducing melanin extrusion. SKH2/J mice also display enhanced expression of the SC acidifying enzyme, secretory phospholipase A2f (sPLA2f). Enhanced barrier function of SKH2/J mice could be attributed to enhanced activity of two acidic pH-dependent, ceramide-generating enzymes, β-glucocerebrosidase and acidic sphingomyelinase, leading to accelerated maturation of SC lamellar bilayers. Finally, organotypic cultures of darkly-pigmented-bearing human keratinocytes display enhanced barrier function in comparison to lightly-pigmented cultures. Together, these results suggest that the superior barrier function of pigmented epidermis can be largely attributed to the pH-lowering impact of melanin persistence/extrusion and enhanced sPLA2f expression. PMID:24732399

  15. Production of luteoskyrin, a hepatotoxic pigment, by Penicillium islandicum Sopp.

    PubMed

    Ueno, Y; Ishikawa, I

    1969-09-01

    Various factors affecting the yields of luteoskyrin, a hepatotoxic mycotoxin, and related pigments in the liquid medium were studied. Maximal yields of luteoskyrin (0.13% by isolation) and of other pigments were attained in the late phase of the cultivation. The yield of the pigment was increased by supplying malt extract, malonic acid, glutamic acid, or asparagine. A useful material for preparation of (14)C-labeled luteoskyrin was 2-(14)C-malonate.

  16. Atmospheric effects in the remote sensing of phytoplankton pigments

    NASA Technical Reports Server (NTRS)

    Gordon, H. R.; Clark, D. K.

    1980-01-01

    The accuracy with which relevant atmospheric parameters must be estimated to derive photoplankton pigment concentrations of a given accuracy, from measurements of the ocean's apparent spectral radiance at satellite altitudes, is examined. A phytoplankton pigment algorithm is developed which relates the pigment concentration (c) to the three ratios of upwelling radiance just beneath the sea surface which can be formed from wavelengths (lambda) 440, 520 and 550 nm.

  17. Locating structures and evolution pathways of reconstructed rutile TiO2(011) using genetic algorithm aided density functional theory calculations.

    PubMed

    Ding, Pan; Gong, Xue-Qing

    2016-05-01

    Titanium dioxide (TiO2) is an important metal oxide that has been used in many different applications. TiO2 has also been widely employed as a model system to study basic processes and reactions in surface chemistry and heterogeneous catalysis. In this work, we investigated the (011) surface of rutile TiO2 by focusing on its reconstruction. Density functional theory calculations aided by a genetic algorithm based optimization scheme were performed to extensively sample the potential energy surfaces of reconstructed rutile TiO2 structures that obey (2 × 1) periodicity. A lot of stable surface configurations were located, including the global-minimum configuration that was proposed previously. The wide variety of surface structures determined through the calculations performed in this work provide insight into the relationship between the atomic configuration of a surface and its stability. More importantly, several analytical schemes were proposed and tested to gauge the differences and similarities among various surface structures, aiding the construction of the complete pathway for the reconstruction process.

  18. FRACTIONATION OF THE EYE PIGMENTS OF DROSOPHILA MELANOGASTER.

    PubMed

    Wald, G; Allen, G

    1946-09-20

    Eye pigments of normal and mutant types of D. melanogaster have been extracted with water and fractionated by chromatographic adsorption on powdered talc. Spectra of all the fractions obtainable in solution have been measured and the general chemical behavior of the pigments is described. Two chemically distinct groups of pigments are found, to be identified with the earlier designated red and brown components. The red component in the wild-type eye contains three well defined pigments, two of them capable of further subdivision so that the total number of fractions obtained is five. There is also present a brown component pigment which could not be treated quantitatively by the methods employed. All members of the wild-type red component are found in cinnabar eyes, unaccompanied by the brown component. Conversely, brown eyes contain a pigment indistinguishable from the wild-type brown component, virtually alone. In sepia eyes, one red component and two brown component pigments can be distinguished, all three pigments differing from those of wild-type eyes. Pigments apparently identical with those found in wild-type melanogaster eyes have also been found in D. virilis.

  19. Dichroism measurements in forensic fibre examination: part 5-pigmented fibres.

    PubMed

    De Wael, K; Lepot, L

    2012-09-01

    A number of pigmented fibre samples were examined with plane polarized light on their dichroic behaviour by optical light microscopy (OLM) and microspectrophotometry with plane polarized light (MSP-PPL). It was found that about half of the samples show a strong dichroic effect and another 20% have a weak dichroism. Both regular (80%) and inversed dichroic effects (20%) occur. The dichroic characteristics of pigmented fibres can be compared to these of sheet polarizers. It is suggested that the dichroic behaviour of pigmented fibres depends strongly on the crystal structure (shape of the pigment grains) and the draw ratio (orientation of the polymer chains).

  20. Abnormal pigmentation within cutaneous scars: A complication of wound healing

    PubMed Central

    Chadwick, Sarah; Heath, Rebecca; Shah, Mamta

    2012-01-01

    Abnormally pigmented scars are an undesirable consequence of cutaneous wound healing and are a complication every single individual worldwide is at risk of. They present a challenge for clinicians, as there are currently no definitive treatment options available, and render scars much more noticeable making them highly distressing for patients. Despite extensive research into both wound healing and the pigment cell, there remains a scarcity of knowledge surrounding the repigmentation of cutaneous scars. Pigment production is complex and under the control of many extrinsic and intrinsic factors and patterns of scar repigmentation are unpredictable. This article gives an overview of human skin pigmentation, repigmentation following wounding and current treatment options. PMID:23162241

  1. Neodymium-YAG transscleral cyclophotocoagulation. The role of pigmentation

    SciTech Connect

    Cantor, L.B.; Nichols, D.A.; Katz, L.J.; Moster, M.R.; Poryzees, E.; Shields, J.A.; Spaeth, G.L. )

    1989-08-01

    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.

  2. Early Diagenesis of Plant Pigments in Hudson River Sediments

    NASA Astrophysics Data System (ADS)

    Bianchi, Thomas S.; Dibb, Jack E.; Findlay, Stuart

    1993-06-01

    Plant pigment concentrations were measured using high performance liquid chromatography in Hudson River sediments. Sedimentation rates and mixing characteristics were determined from depth profiles of the naturally occurring radionuclides 7Be, 210Pb. Previous estimates of the mean-lives (1/λ) of plant pigments (chlorophylls a and b, fucoxanthin) from laboratory experiments, indicate a range of c. 20-40 days. However, in the field, we observed that these pigments decreased less rapidly with depth and penetrated deeper than 7Be (mean-life 77 days) in Hudson sediments 95% of the time. Assuming similar mixing processes for particles carrying 7Be and pigments, this indicates that pigment decay rates in the field are slower than the 0·013 day -1 decay rate of 7Be, hence, more than 2-fold slower than the derived laboratory rates. We believe that high inputs of vascular plant detritus in the Hudson may increase the complexation of humic substances with pigments resulting in slower decay rates. While most pigments showed an exponential decrease with sediment depth, lutein concentrations generally increased with depth. This pattern of decay resistance is in agreement with laboratory experiments which show that lutein is the most decay resistant among dominant pigments. These data along with other studies demonstrate that the carotenoids lacking the 5,6-epoxide group (i.e., lutein) are more decay resistant than pigments that contain it (i.e., fucoxanthin).

  3. Reflective color display using thermochromic pigments.

    PubMed

    Heo, Kyong Chan; Sohn, Youngku; Yi, Jonghoon; Kwon, Jin Hyuk; Son, Phil Kook; Gwag, Jin Seog

    2012-06-20

    A reflective thermochromic display fabricated by a very simple method using three kinds of thermochromic pigments is produced and its thermo-optical characteristics are investigated. The display exhibits maximum red, green, and blue reflectances of 38%, 30%, and 35%, respectively. The reflective display cell shows continuous gray color with changing temperature, which is crucial for multicolor displays. It also shows an excellent viewing angle above 80° without any of the additional optical components that are required in liquid crystal displays. We expect that this display technology will be used for outdoor billboard information display applications.

  4. Characterization of Brevibacterium linens pigmentation using spectrocolorimetry.

    PubMed

    Guyomarc'h, F; Binet, A; Dufossé, L

    2000-06-15

    Spectrocolorimetry was used for the evaluation of Brevibacterium linens pigmentation. A total of 23 strains of Brevibacterium linens, from various sources, were plated onto solid agar media and their color coordinates were measured and expressed by the L*a*b* colorimetric system. All the strains were located along a straight line with a hue of 66 degrees (orange color). The effect of light exposure versus storage in the dark was also investigated using this approach. Three groups with distinct behaviors were demonstrated for the 23 B. linens strains.

  5. Corrosion-Indicating Pigment And Probes

    NASA Technical Reports Server (NTRS)

    Bar-Cohen, Yoseph; Bugga, Ratnakumar V.; Attia, Alan I.

    1993-01-01

    Proposed hydrogen-sensitive paint for metal structures changes color at onset of corrosion, involving emission of hydrogen as result of electrochemical reactions. Pigment of suitable paint includes rhodium compound RhCl(PPh3)3, known as Wilkinson's catalyst. As coating on critical parts of such structures as bridges and aircraft, paint gives early warning of corrosion, and parts thus repaired or replaced before failing catastrophically. Reveals corrosion before it becomes visible to eye. Inspection for changes in color not ordinarily necessitate removal of structure from service, and costs less than inspection by x-ray or thermal neutron radiography, ultrasonic, eddy-current, or acoustic-emission techniques.

  6. Method of preparing zinc orthotitanate pigment

    NASA Technical Reports Server (NTRS)

    Gates, D. W.; Harada, Y.; Logan, W. R.; Gilligan, J. E. (Inventor)

    1977-01-01

    Zinc orthotitanate suitable for use as a pigment for spacecraft thermal control coatings is prepared by heating a slightly zinc deficient reaction mixture of precipitated oxalates of zinc and titanium. The reaction mixture can be formed by coprecipitation of zinc and titanium oxalates from chloride solution or by mixing separately precipitated oxalates. The mixture is first heated to 400 to 600 C to remove volatiles and is then rapidly heated at 900 to 1200 C. Zinc orthotitanate produced by this method exhibits the very fine particle size needed for thermal control coatings as well as stability in a space environment.

  7. Mutations in CTNNA1 cause butterfly-shaped pigment dystrophy and perturbed retinal pigment epithelium integrity

    PubMed Central

    Saksens, Nicole T.M.; Krebs, Mark P.; Schoenmaker-Koller, Frederieke E.; Hicks, Wanda; Yu, Minzhong; Shi, Lanying; Rowe, Lucy; Collin, Gayle B.; Charette, Jeremy R.; Letteboer, Stef J.; Neveling, Kornelia; van Moorsel, Tamara W.; Abu-Ltaif, Sleiman; De Baere, Elfride; Walraedt, Sophie; Banfi, Sandro; Simonelli, Francesca; Cremers, Frans P.M.; Boon, Camiel J.F.; Roepman, Ronald; Leroy, Bart P.; Peachey, Neal S.; Hoyng, Carel B.; Nishina, Patsy M.; den Hollander, Anneke I.

    2015-01-01

    Butterfly-shaped pigment dystrophy is an eye disease characterized by lesions in the macula that can resemble the wings of a butterfly. Here, we report the identification of heterozygous missense mutations in the α-catenin 1 (CTNNA1) gene in three families with butterfly-shaped pigment dystrophy. In addition, we identified a Ctnna1 missense mutation in a chemically induced mouse mutant, tvrm5. Parallel clinical phenotypes were observed in the retinal pigment epithelium (RPE) of individuals with butterfly-shaped pigment dystrophy and in tvrm5 mice, including pigmentary abnormalities, focal thickening and elevated lesions, and decreased light-activated responses. Morphological studies in tvrm5 mice revealed increased cell shedding and large multinucleated RPE cells, suggesting defects in intercellular adhesion and cytokinesis. This study identifies CTNNA1 gene variants as a cause of macular dystrophy, suggests that CTNNA1 is involved in maintaining RPE integrity, and suggests that other components that participate in intercellular adhesion may be implicated in macular disease. PMID:26691986

  8. 'Shadow sign' in congenital hypertrophy of the retinal pigment epithelium of young myopic pigmented patients.

    PubMed

    Chang, M Y; McBeath, J B; McCannel, C A; McCannel, T A

    2016-01-01

    PURPOSE Congenital hypertrophy of the retinal pigment epithelium (CHRPE) may simulate choroidal melanoma in certain cases. We report unique clinical features we have observed in cases of CHRPE in young myopic pigmented patients.METHODS Patients who were referred for evaluation of a suspicious choroidal lesion and found to have a CHRPE lesion with the clinical appearance of lesion elevation and a subretinal fluid-like 'shadow sign' were included. Patient and lesion characteristics were tabulated. Available images, including fundus photography, ultrasonography, optical coherence tomography (OCT), and fluorescein angiography (FA) were reviewed.ResultsSix patients were included. The 'shadow sign' was anterior to the CHRPE lesion in all cases. The mean age of the patients was 27.3 years. The ethnicities of the patients were Chinese (n=1), Hispanic (n=3), or African-American (n=2). Five of six patients were myopic.CONCLUSIONS Although most CHRPE lesions appear flat on ophthalmoscopy, lesions in young myopic patients of pigmented ethnicities may appear elevated with a 'shadow sign' due to 'dark without pressure.' This new finding may be related to the vitreoretinal interface in young myopic pigmented patients and must be distinguished from true subretinal fluid and lesion thickness, which are often observed in choroidal melanoma.

  9. Nematode endogenous small RNA pathways

    PubMed Central

    Hoogstrate, Suzanne W; Volkers, Rita JM; Sterken, Mark G; Kammenga, Jan E; Snoek, L Basten

    2014-01-01

    The discovery of small RNA silencing pathways has greatly extended our knowledge of gene regulation. Small RNAs have been presumed to play a role in every field of biology because they affect many biological processes via regulation of gene expression and chromatin remodeling. Most well-known examples of affected processes are development, fertility, and maintenance of genome stability. Here we review the role of the three main endogenous small RNA silencing pathways in Caenorhabditis elegans: microRNAs, endogenous small interfering RNAs, and PIWI-interacting RNAs. After providing an entry-level overview on how these pathways function, we discuss research on other nematode species providing insight into the evolution of these small RNA pathways. In understanding the differences between the endogenous small RNA pathways and their evolution, a more comprehensive picture is formed of the functions and effects of small RNAs. PMID:25340013

  10. [Pathways of flowering regulation in plants].

    PubMed

    Liu, Yongping; Yang, Jing; Yang, Mingfeng

    2015-11-01

    Flowering, the floral transition from vegetative growth to reproductive growth, is induced by diverse endogenous and exogenous cues, such as photoperiod, temperature, hormones and age. Precise flowering time is critical to plant growth and evolution of species. The numerous renewal molecular and genetic results have revealed five flowering time pathways, including classical photoperiod pathway, vernalization pathway, autonomous pathway, gibberellins (GA) pathway and newly identified age pathway. These pathways take on relatively independent role, and involve extensive crosstalks and feedback loops. This review describes the complicated regulatory network of this floral transition to understand the molecular mechanism of flowering and provide references for further research in more plants.

  11. Quantum-classical model of retinal photoisomerization reaction in visual pigment rhodopsin.

    PubMed

    Lakhno, V D; Shigaev, A S; Feldman, T B; Nadtochenko, V A; Ostrovsky, M A

    2016-11-01

    A quantum-classical model of photoisomerization of the visual pigment rhodopsin chromophore is proposed. At certain (and more realistic) parameter value combinations, the model is shown to accurately reproduce a number of independent experimental data on the photoreaction dynamics: the quantum yield, the time to reach the point of conical intersection of potential energy surfaces, the termination time of the evolution of quantum subsystem, as well as the characteristic low frequencies of retinal molecular lattice fluctuations during photoisomerization. In addition, the model behavior is in good accordance with experimental data about coherence and local character of quantum transition.

  12. Melanin pigmentation in mammalian skin and its hormonal regulation.

    PubMed

    Slominski, Andrzej; Tobin, Desmond J; Shibahara, Shigeki; Wortsman, Jacobo

    2004-10-01

    Cutaneous melanin pigment plays a critical role in camouflage, mimicry, social communication, and protection against harmful effects of solar radiation. Melanogenesis is under complex regulatory control by multiple agents interacting via pathways activated by receptor-dependent and -independent mechanisms, in hormonal, auto-, para-, or intracrine fashion. Because of the multidirectional nature and heterogeneous character of the melanogenesis modifying agents, its controlling factors are not organized into simple linear sequences, but they interphase instead in a multidimensional network, with extensive functional overlapping with connections arranged both in series and in parallel. The most important positive regulator of melanogenesis is the MC1 receptor with its ligands melanocortins and ACTH, whereas among the negative regulators agouti protein stands out, determining intensity of melanogenesis and also the type of melanin synthesized. Within the context of the skin as a stress organ, melanogenic activity serves as a unique molecular sensor and transducer of noxious signals and as regulator of local homeostasis. In keeping with these multiple roles, melanogenesis is controlled by a highly structured system, active since early embryogenesis and capable of superselective functional regulation that may reach down to the cellular level represented by single melanocytes. Indeed, the significance of melanogenesis extends beyond the mere assignment of a color trait.

  13. Lyar Is a New Ligand for Retinal Pigment Epithelial Phagocytosis.

    PubMed

    Guo, Feiye; Ding, Ying; Caberoy, Nora B; Alvarado, Gabriela; Liu, Robert; Shen, Chen; Yu, Jisu; Zhou, Yixiong; Salero, Enrique; LeBlanc, Michelle E; Wang, Weiwen; Li, Wei

    2015-10-01

    Phagocytosis is critical to tissue homeostasis, as highlighted by phagocytosis defect of retinal pigment epithelial (RPE) cells with debris accumulation, photoreceptor degeneration and blindness. Phagocytosis ligands are the key to delineating molecular mechanisms and functional roles of phagocytes, but are traditionally identified in individual cases with technical challenges. We recently developed open reading frame phage display (OPD) for phagocytosis-based functional cloning (PFC) to identify unknown ligands. One of the identified ligands was Ly-1 antibody reactive clone (Lyar) with functions poorly defined. Herein, we characterized Lyar as a new ligand to stimulate RPE phagocytosis. In contrast to its reported nucleolar expression, immunohistochemistry showed that Lyar was highly expressed in photoreceptor outer segments (POSs) of the retina. Cytoplasmic Lyar was released from apoptotic cells, and selectively bound to shed POSs and apoptotic cells, but not healthy cells. POS vesicles engulfed through Lyar-dependent pathway were targeted to phagosomes and colocalized with phagosome marker Rab7. These results suggest that Lyar is a genuine RPE phagocytosis ligand, which in turn supports the validity of OPD/PFC as the only available approach for unbiased identification of phagocytosis ligands with broad applicability to various phagocytes.

  14. Leukocyte tyrosine kinase functions in pigment cell development.

    PubMed

    Lopes, Susana S; Yang, Xueyan; Müller, Jeanette; Carney, Thomas J; McAdow, Anthony R; Rauch, Gerd-Jörg; Jacoby, Arie S; Hurst, Laurence D; Delfino-Machín, Mariana; Haffter, Pascal; Geisler, Robert; Johnson, Stephen L; Ward, Andrew; Kelsh, Robert N

    2008-03-07

    A fundamental problem in developmental biology concerns how multipotent precursors choose specific fates. Neural crest cells (NCCs) are multipotent, yet the mechanisms driving specific fate choices remain incompletely understood. Sox10 is required for specification of neural cells and melanocytes from NCCs. Like sox10 mutants, zebrafish shady mutants lack iridophores; we have proposed that sox10 and shady are required for iridophore specification from NCCs. We show using diverse approaches that shady encodes zebrafish leukocyte tyrosine kinase (Ltk). Cell transplantation studies show that Ltk acts cell-autonomously within the iridophore lineage. Consistent with this, ltk is expressed in a subset of NCCs, before becoming restricted to the iridophore lineage. Marker analysis reveals a primary defect in iridophore specification in ltk mutants. We saw no evidence for a fate-shift of neural crest cells into other pigment cell fates and some NCCs were subsequently lost by apoptosis. These features are also characteristic of the neural crest cell phenotype in sox10 mutants, leading us to examine iridophores in sox10 mutants. As expected, sox10 mutants largely lacked iridophore markers at late stages. In addition, sox10 mutants unexpectedly showed more ltk-expressing cells than wild-type siblings. These cells remained in a premigratory position and expressed sox10 but not the earliest neural crest markers and may represent multipotent, but partially-restricted, progenitors. In summary, we have discovered a novel signalling pathway in NCC development and demonstrate fate specification of iridophores as the first identified role for Ltk.

  15. Skin pigmentation provides evidence of convergent melanism in extinct marine reptiles.

    PubMed

    Lindgren, Johan; Sjövall, Peter; Carney, Ryan M; Uvdal, Per; Gren, Johan A; Dyke, Gareth; Schultz, Bo Pagh; Shawkey, Matthew D; Barnes, Kenneth R; Polcyn, Michael J

    2014-02-27

    Throughout the animal kingdom, adaptive colouration serves critical functions ranging from inconspicuous camouflage to ostentatious sexual display, and can provide important information about the environment and biology of a particular organism. The most ubiquitous and abundant pigment, melanin, also has a diverse range of non-visual roles, including thermoregulation in ectotherms. However, little is known about the functional evolution of this important biochrome through deep time, owing to our limited ability to unambiguously identify traces of it in the fossil record. Here we present direct chemical evidence of pigmentation in fossilized skin, from three distantly related marine reptiles: a leatherback turtle, a mosasaur and an ichthyosaur. We demonstrate that dark traces of soft tissue in these fossils are dominated by molecularly preserved eumelanin, in intimate association with fossilized melanosomes. In addition, we suggest that contrary to the countershading of many pelagic animals, at least some ichthyosaurs were uniformly dark-coloured in life. Our analyses expand current knowledge of pigmentation in fossil integument beyond that of feathers, allowing for the reconstruction of colour over much greater ranges of extinct taxa and anatomy. In turn, our results provide evidence of convergent melanism in three disparate lineages of secondarily aquatic tetrapods. Based on extant marine analogues, we propose that the benefits of thermoregulation and/or crypsis are likely to have contributed to this melanisation, with the former having implications for the ability of each group to exploit cold environments.

  16. Controlled exosome release from the retinal pigment epithelium in situ.

    PubMed

    Locke, Christina J; Congrove, Nicole R; Dismuke, W Michael; Bowen, Trent J; Stamer, W Daniel; McKay, Brian S

    2014-12-01

    Retinal Pigment Epithelial cells (RPE) express both GPR143 and myocilin, which interact in a signal transduction-dependent manner. In heterologous systems, activation of GPR143 with ligand causes transient recruitment of myocilin to internalized receptors, which appears to be the entry point of myocilin to the endocytic pathway. In some but not all cells, myocilin also traffics through the multivesicular body (MVB) and is released on the surface of exosomes in a signal transduction-dependent fashion. Little is known regarding the role of exosomes in RPE, but they likely serve as a mode of communication between the RPE and the outer retina. In this study, we used posterior poles with retina removed from fresh human donor eyes as a model to test the relationship between GPR143, myocilin, and exosomes in an endogenous system. We isolated exosomes released by RPE using differential centrifugation of media conditioned by the RPE for 25 min, and then characterized the exosomes using nanoparticle tracking to determine the number and size of the exosomes. Next, we tested whether ligand stimulation of GPR143 using l-DOPA altered RPE exosome release. Finally, we investigated whether myocilin was present on the exosomes released by RPE and whether l-DOPA stimulation of GPR143 caused recruitment of myocilin to the endocytic pathway, as we have previously observed using cultured cells. Activation of GPR143 halted RPE exosome release, while simultaneously recruiting myocilin to the endocytic compartment. Together, our results indicate that GPR143 and myocilin function in a signal transduction system that can control exosome release from RPE.

  17. Functional annotation of the human retinal pigment epithelium transcriptome

    PubMed Central

    Booij, Judith C; van Soest, Simone; Swagemakers, Sigrid MA; Essing, Anke HW; Verkerk, Annemieke JMH; van der Spek, Peter J; Gorgels, Theo GMF; Bergen, Arthur AB

    2009-01-01

    Background To determine level, variability and functional annotation of gene expression of the human retinal pigment epithelium (RPE), the key tissue involved in retinal diseases like age-related macular degeneration and retinitis pigmentosa. Macular RPE cells from six selected healthy human donor eyes (aged 63–78 years) were laser dissected and used for 22k microarray studies (Agilent technologies). Data were analyzed with Rosetta Resolver, the web tool DAVID and Ingenuity software. Results In total, we identified 19,746 array entries with significant expression in the RPE. Gene expression was analyzed according to expression levels, interindividual variability and functionality. A group of highly (n = 2,194) expressed RPE genes showed an overrepresentation of genes of the oxidative phosphorylation, ATP synthesis and ribosome pathways. In the group of moderately expressed genes (n = 8,776) genes of the phosphatidylinositol signaling system and aminosugars metabolism were overrepresented. As expected, the top 10 percent (n = 2,194) of genes with the highest interindividual differences in expression showed functional overrepresentation of the complement cascade, essential in inflammation in age-related macular degeneration, and other signaling pathways. Surprisingly, this same category also includes the genes involved in Bruch's membrane (BM) composition. Among the top 10 percent of genes with low interindividual differences, there was an overrepresentation of genes involved in local glycosaminoglycan turnover. Conclusion Our study expands current knowledge of the RPE transcriptome by assigning new genes, and adding data about expression level and interindividual variation. Functional annotation suggests that the RPE has high levels of protein synthesis, strong energy demands, and is exposed to high levels of oxidative stress and a variable degree of inflammation. Our data sheds new light on the molecular composition of BM, adjacent to the RPE, and is useful for

  18. Photoinduced changes in photosystem II pigments

    NASA Astrophysics Data System (ADS)

    Andreeva, Atanaska S.; Busheva, Mira C.; Stoitchkova, Katerina V.; Tzonova, Iren K.

    2010-11-01

    The photosynthetic apparatus in higher plants performs two seemingly opposing tasks: efficient harvest of sunlight, but also rapid and harmless dissipation of excess light energy as heat to avoid deleterious photodamage. In order to study this process in pigment-protein supercomplexes of photosystem II (PSII), 77 K fluorescence and room temperature resonance Raman (RR) spectroscopy were applied to investigate the changes in structure and spectral properties of the pigments in spinach PSII membranes. The high-light treatment results in a strong quenching of the fluorescence (being largest when the excitation is absorbed by carotenoids) and a red-shift of the main maximum. Decomposition of the fluorescence spectra into four bands revealed intensive quenching of F685 and F695 bands, possible bleaching of chlorophyll a, enhanced extent of light harvesting complexes (LHCII) aggregation and increased energy transfer to aggregated LHCII. The analysis of RR spectra revealed the predominant contribution of ß-carotene (ß-Car) upon 457.8 and 488 nm excitations and lutein (Lut) at 514.5 nm. During prolonged exposure to strong light no significant bleaching of ß-Car and weak photobleaching of Lut is observed. The results will contribute to the efforts to produce more efficient and robust solar cells when exposed to fluctuations in light intensity.

  19. Enamel ultrastructure in pigmented hypomaturation amelogenesis imperfecta.

    PubMed

    Wright, J T; Lord, V; Robinson, C; Shore, R

    1992-10-01

    Hypomaturation amelogenesis imperfecta (AI) is a hereditary condition of enamel that is presumed to result from defects during the maturation stage of enamel development. This study characterized the enamel ultrastructure and enamel crystallite morphology, as well as the distribution of organic material in enamel affected with pigmented hypomaturation AI. Enamel exhibiting autosomal recessive pigmented hypomaturation AI was sectioned or fractured and examined using light microscopy, scanning electron microscopy and transmission electron microscopy. Enamel samples were treated with 30% NaOCl or 8 M urea to remove organic components and determine the effect of deproteinization on crystallite morphology. These were compared with untreated normal enamel samples. The enamel crystallites in hypomaturation AI exhibited considerable variability in size and morphology. Examination of deproteinized tissue indicated that the AI crystallites had a thick coating, presumably of organic or partially mineralized material, which was not visible in normal enamel. The results of this investigation provide further evidence that hypomaturation AI is associated with the retention of organic material that is most probably enamel protein. Enamel protein retention is likely to be involved in the inhibition of normal crystallite growth resulting in the morphological crystallite abnormalities associated with this disorder.

  20. Chlorophyll and carotenoid pigments of prochloron (prochlorophyta)

    NASA Technical Reports Server (NTRS)

    Paerl, H. W.; Lewin, R. A.; Cheng, L.

    1983-01-01

    High-performance liquid chromatography (HPLC) with a gradient-elution technique was utilized to separate and quantify chlorophylls a and b as well as major carotenoid pigments present in freeze-dried preprations of prochloron-didemnid associations and in Prochloron cells separated from host colonies. Results confirm earlier spectrophotometric evidence for both chlorophylls a and b in this prokaryote. Chlorophyll a:b ratios range from 4.14 to 19.71; generally good agreement was found between ratios determined in isolated cell preprations and in symbiotic colonies (in hospite). These values are 1.5 to 5-fold higher than ratios determined in a variety of eukaryotic green plants. The carotenoids in Prochloron are quantitatively and qualitatively similar to those found in various freshwater and marine blue-green algae (cyanopbytes) from high-light environments. However, Prochloron differs from cyanophytes by the absence of myxoxanthophyll and related glycosidic carotenoids. It pigment characteristics are considered sufficiently different from those of cyanophytes to justify its assignment to a separate algal division.

  1. Human skin pigmentation, migration and disease susceptibility

    PubMed Central

    Jablonski, Nina G.; Chaplin, George

    2012-01-01

    Human skin pigmentation evolved as a compromise between the conflicting physiological demands of protection against the deleterious effects of ultraviolet radiation (UVR) and photosynthesis of UVB-dependent vitamin D3. Living under high UVR near the equator, ancestral Homo sapiens had skin rich in protective eumelanin. Dispersals outside of the tropics were associated with positive selection for depigmentation to maximize cutaneous biosynthesis of pre-vitamin D3 under low and highly seasonal UVB conditions. In recent centuries, migrations and high-speed transportation have brought many people into UVR regimes different from those experienced by their ancestors and, accordingly, exposed them to new disease risks. These have been increased by urbanization and changes in diet and lifestyle. Three examples—nutritional rickets, multiple sclerosis (MS) and cutaneous malignant melanoma (CMM)—are chosen to illustrate the serious health effects of mismatches between skin pigmentation and UVR. The aetiology of MS in particular provides insight into complex and contingent interactions of genetic and environmental factors necessary to trigger lethal disease states. Low UVB levels and vitamin D deficiencies produced by changes in location and lifestyle pose some of the most serious disease risks of the twenty-first century. PMID:22312045

  2. Fruit flesh betacyanin pigments in hylocereus cacti.

    PubMed

    Wybraniec, Sławomir; Mizrahi, Yosef

    2002-10-09

    Determination of profiles and total contents of betacyanins in cactus fruits of Hylocereus species using chromatographic and spectrophotometric method is described. The investigated species were H. polyrhizus, H. purpusii, H. costaricensis, H. sp. 487 (all red-flesh species and hybrids made among them), and the white- or red-flesh species H. undatus. Hybrids included hybrid 1 (H. undatus white-flesh clone and H. sp. 487), hybrid 35 (H. sp. 487 and H. polyrhizus), and the reciprocal hybrid hybrid 95 (H. polyrhizus and H. sp. 487). Fruits of H. polyrhizus exhibited the highest relative concentration (expressed as percentage of the total HPLC peak area) of hylocerenin, a recently discovered pigment, and a high relative concentration of phyllocactin. Hylocerenin and isohylocerenin, present in fruits at relative concentrations of 11.7 and 5.8%, respectively, are probably responsible for the fluorescent color of the fruit pulp. H. costaricensis fruits have a much higher content of phyllocactin (63.9%), which is almost 4 times higher than the betanin content. These differences in pigment concentrations might explain the differences in red hues of the flesh of these fruits.

  3. Simultaneous quantification of opiates and effect of pigmentation on its deposition in hair.

    PubMed

    Lee, Sooyeun; Han, Eunyoung; Kim, Eunmi; Choi, Hwakyung; Chung, Heesun; Oh, Seung Min; Yun, Young Mi; Jwa, Seok Hun; Chung, Kyu Hyuck

    2010-11-01

    In forensic toxicology, the abuse of various opiate preparations, such as raw opium and heroin, is of interest since the metabolic pathways of these opiates overlap. Although the pharmaco(toxico)kinetics in hair is not clearly understood, melanin is thought to play a key part in the incorporation and distribution of drugs and metabolites in hair. Therefore, in the present study, a simultaneous quantification method for the determination of codeine, morphine, norcodeine, normorphine and 6-acetylmorphine (6-AM) in hair was developed in order to analytically diagnose chronic users of opiates including morphine and codeine preparations, raw opium and heroin. Furthermore, the effect of hair pigmentation on the distribution of opiates in hair was investigated using lean Zucker rats with both dark grey and white hair on the same body. Opiates were extracted using 0.1 M hydrochloric acid followed by solid phase extraction. The extracts were derivatized with N-methyl-N-(trimethylsilyl)trifluoroacetamide and analyzed using gas chromatography/mass spectrometry (GC/MS). The method was fully validated and applied to the animal study. In conclusion, the current study demonstrates that codeine, morphine and their metabolites were successfully determined in both pigmented and non-pigmented hair. However, the melanin content plays an important role in the degree of incorporation of morphine, codeine and their metabolites into hair.

  4. Evolving visual pigments: hints from the opsin-based proteins in a phylogenetically old "eyeless" invertebrate.

    PubMed

    Santillo, Silvia; Orlando, Pierangelo; De Petrocellis, Luciano; Cristino, Luigia; Guglielmotti, Vittorio; Musio, Carlo

    2006-01-01

    Visual pigments are photosensitive receptor proteins that trigger the transduction process producing the visual excitation once they have absorbed photons. In spite of the molecular and morpho-functional complexity that has characterized the development of animal eyes and eyeless photoreceptive systems, opsin-based protein family appears ubiquous along metazoan visual systems. Moreover, in addition to classic rhodopsin photoreceptors, all Metazoa have supplementary non-visual photosensitive structures, mainly located in the central nervous system, that sense light without forming an image and that rather regulate the organism's temporal physiology. The investigation of novel non-visual photopigments exerting extraretinal photoreception is a challenging field in vision research. Here we propose the cnidarian Hydra as a useful tool of investigation for molecular and functional differences between these pigment families. Hydra is the first metazoan owning a nervous system and it is an eyeless invertebrate showing only an extraocular photoreception, as it has no recognized visual or photosensitive structures. In this paper we provide an overview of the molecular and functional features of the opsin-based protein subfamilies and preliminary evidences in a phylogenetically old species of both image-forming and non-visual opsins. Then we give new insights on the molecular biology of Hydra photoreception and on the evolutionary pathways of visual pigments.

  5. Primary Cilia Negatively Regulate Melanogenesis in Melanocytes and Pigmentation in a Human Skin Model

    PubMed Central

    Kim, Eun Sung; Park, So Jung; Bae, Il-Hong; Jo, Yoon Kyung; Jeong, In Young; Kim, Hyoung-June; Lee, Youngjin; Park, Hea Chul; Jeon, Hong Bae; Kim, Ki Woo; Lee, Tae Ryong; Cho, Dong-Hyung

    2016-01-01

    The primary cilium is an organelle protruding from the cell body that senses external stimuli including chemical, mechanical, light, osmotic, fluid flow, and gravitational signals. Skin is always exposed to the external environment and responds to external stimuli. Therefore, it is possible that primary cilia have an important role in skin. Ciliogenesis was reported to be involved in developmental processes in skin, such as keratinocyte differentiation and hair formation. However, the relation between skin pigmentation and primary cilia is largely unknown. Here, we observed that increased melanogenesis in melanocytes treated with a melanogenic inducer was inhibited by a ciliogenesis inducer, cytochalasin D, and serum-free culture. However, these inhibitory effects disappeared in GLI2 knockdown cells. In addition, activation of sonic hedgehog (SHH)-smoothened (Smo) signaling pathway by a Smo agonist, SAG inhibited melanin synthesis in melanocytes and pigmentation in a human skin model. On the contrary, an inhibitor of primary cilium formation, ciliobrevin A1, activated melanogenesis in melanocytes. These results suggest that skin pigmentation may be regulated partly by the induction of ciliogenesis through Smo-GLI2 signaling. PMID:27941997

  6. [Neural crest and vertebrate evolution].

    PubMed

    Le Douarin, Nicole M; Creuzet, Sophie

    2011-01-01

    The neural crest (NC) is a remarkable structure of the Vertebrate embryo, which forms from the lateral borders of the neural plate (designated as neural folds) during neural tube closure. As soon as the NC is formed, its constitutive cells detach and migrate away from the neural primordium along definite pathways and at precise periods of time according to a rostro-caudal progression. The NC cells aggregate in definite places in the developing embryo, where they differentiate into a large variety of cell types including the neurons and glial cells of the peripheral nervous system, the pigment cells dispersed throughout the body and endocrine cells such as the adrenal medulla and the calcitonin producing cells. At the cephalic level only, in higher Vertebrates (but along the whole neural axis in Fishes and Amphibians), the NC is also at the origin of mesenchymal cells differentiating into connective tissue chondrogenic and osteogenic cells. Vertebrates belong to the larger group of Cordates which includes also the Protocordates (Cephalocordates and the Urocordates). All Cordates are characterized by the same body plan with a dorsal neural tube and a notochord which, in Vertebrates, exists only at embryonic stages. The main difference between Protocordates and Vertebrates is the very rudimentary development of cephalic structures in the former. As a result, the process of cephalization is one of the most obvious characteristics of Vertebrates. It was accompanied by the apparition of the NC which can therefore be considered as an innovation of Vertebrates during evolution. The application of a cell marking technique which consists in constructing chimeric embryos between two species of birds, the quail and the chicken, has led to show that the vertebrate head is mainly formed by cells originating from the NC, meaning that this structure was an important asset in Vertebrate evolution. Recent studies, described in this article, have strengthened this view by showing

  7. Pathways of geomorphic evolution of sandstone escarpments in the Góry Stołowe tableland (SW Poland) - Insights from LiDAR-based high-resolution DEM

    NASA Astrophysics Data System (ADS)

    Migoń, Piotr; Kasprzak, Marek

    2016-05-01

    The tableland of the Stołowe Mountains (SW Poland), with its prominent mesas and sandstone-capped escarpments, belongs to the most spectacular geomorphic landscapes of Central Europe. While the gross morphological features of the area have long been recognized, the evolutionary pathways of densely forested and poorly accessible escarpment slopes remained poorly understood. In this paper we use LiDAR data to shed a new light on landform inventories within the escarpments, their spatial patterns and, using process-from-form reasoning, on the longer-term evolution of the escarpments. Four sites, two on each major escarpment, have been subject to detailed analysis which involved examination of shaded relief, slope, plan and profile curvature and topographic wetness index. In each case, the 1 × 1 m model was used, while for the most complex site at Mt. Szczeliniec Wielki the results were compared with the 5 × 5 m model to check the impact of model resolution on geomorphic interpretation. Despite some loss of information involved in model re-interpolation to the coarser scale, the main features of escarpment morphology could still be recognized. On the other hand, automatic landform classification based on the calculation of Topographic Position Index from the 10 × 10 m model and performed for the entire tableland failed to reveal differences between various sections of the escarpments, detectable on finer models. The analysis of spatial patterns of minor landforms within the escarpments, identified on LiDAR-derived models shows that no single pathway of escarpment evolution exists. Both the upper slopes (in sandstone caprock) and the mid-slopes (in weaker rocks) show signs of instability and these are not necessarily coupled. Large-scale caprock failures do occur but seem rare and localized. Sandstone free faces are rather subject to continuous slow retreat by detachment of individual joint-bound blocks. Another zone of instability occurs well below the caprock and

  8. Development of tyrosine hydroxylase-immunoreactive cell populations and fiber pathways in the brain of the dogfish Scyliorhinus canicula: new perspectives on the evolution of the vertebrate catecholaminergic system.

    PubMed

    Carrera, Iván; Anadón, Ramón; Rodríguez-Moldes, Isabel

    2012-11-01

    Developmental studies of the central catecholaminergic (CA) system are essential for understanding its evolution. To obtain knowledge about the CA system in chondrichthyans, an ancient gnathostome group, we used immunohistochemical techniques for detecting tyrosine hydroxylase (TH), the initial rate-limiting enzyme of the CA synthesis, to study: 1) the neuromery of developing TH-immunoreactive (ir) neuronal populations, 2) the development of TH-ir innervation, and 3) the organization of TH-ir cells and fibers in the brain of postembryonic stages of the shark Scyliorhinus canicula. The first TH-ir cells appeared in the hypothalamus and rostral diencephalon (suprachiasmatic, posterior recess and posterior tubercle nuclei at embryonic stage 26, and dorsomedial hypothalamus at stage 28); then in more caudal basal regions of the diencephalon and rostral mesencephalon (substantia nigra/ventral tegmental area); and later on in the anterior (locus coeruleus/nucleus subcoeruleus) and posterior (vagal lobe and reticular formation) rhombencephalon. The appearance of TH-ir cells in the telencephalon (pallium) was rather late (stage [S]31) with respect to the other TH-ir prosencephalic populations. The first TH-ir fibers arose from cells of the posterior tubercle (S30) and formed recognizable ascending (toward dorsal and rostral territories) and descending pathways at S31. When the second half of embryonic development started (S32), TH-ir fibers innervated most brain areas, and nearly all TH-ir cell groups of the postembryonic brain were already established. This study provides key information about the evolution of the developmental patterns of central CA systems in fishes and thus may help in understanding how the vertebrate CA systems have evolved.

  9. Signaling Pathways in Melanogenesis

    PubMed Central

    D’Mello, Stacey A. N.; Finlay, Graeme J.; Baguley, Bruce C.; Askarian-Amiri, Marjan E.

    2016-01-01

    Melanocytes are melanin-producing cells found in skin, hair follicles, eyes, inner ear, bones, heart and brain of humans. They arise from pluripotent neural crest cells and differentiate in response to a complex network of interacting regulatory pathways. Melanins are pigment molecules that are endogenously synthesized by melanocytes. The light absorption of melanin in skin and hair leads to photoreceptor shielding, thermoregulation, photoprotection, camouflage and display coloring. Melanins are also powerful cation chelators and may act as free radical sinks. Melanin formation is a product of complex biochemical events that starts from amino acid tyrosine and its metabolite, dopa. The types and amounts of melanin produced by melanocytes are determined genetically and are influenced by a variety of extrinsic and intrinsic factors such as hormonal changes, inflammation, age and exposure to UV light. These stimuli affect the different pathways in melanogenesis. In this review we will discuss the regulatory mechanisms involved in melanogenesis and explain how intrinsic and extrinsic factors regulate melanin production. We will also explain the regulatory roles of different proteins involved in melanogenesis. PMID:27428965

  10. SIGNALING PATHWAYS IN MELANOSOME BIOGENESIS AND PATHOLOGY

    PubMed Central

    Schiaffino, Maria Vittoria

    2010-01-01

    Melanosomes are the specialized intracellular organelles of pigment cells devoted to the synthesis, storage and transport of melanin pigments, which are responsible for most visible pigmentation in mammals and other vertebrates. As a direct consequence, any genetic mutation resulting in alteration of melanosomal function, either because affecting pigment cell survival, migration and differentiation, or because interfering with melanosome biogenesis, transport and transfer to keratinocytes, is immediately translated into color variations of skin, fur, hair or eyes. Thus, over one hundred genes and proteins have been identified as pigmentary determinants in mammals, providing us with a deep understanding of this biological system, which functions by using mechanisms and processes that have parallels in other tissues and organs. In particular, many genes implicated in melanosome biogenesis have been characterized, so that melanosomes represent an incredible source of information and a model for organelles belonging to the secretory pathway. Furthermore, the function of melanosomes can be associated with common physiological phenotypes, such as variation of pigmentation among individuals, and with rare pathological conditions, such as albinism, characterized by severe visual defects. Among the most relevant mechanisms operating in melanosome biogenesis are the signal transduction pathways mediated by two peculiar G protein-coupled receptors: the melanocortin-1 receptor (MC1R), involved in the fair skin/red hair phenotype and skin cancer; and OA1 (GPR143), whose loss-of-function results in X-linked ocular albinism. This review will focus on the most recent novelties regarding the functioning of these two receptors, by highlighting emerging signaling mechanisms and general implications for cell biology and pathology. PMID:20381640

  11. The genetic architecture of coordinately evolving male wing pigmentation and courtship behavior in Drosophila elegans and Drosophila gunungcola.

    PubMed

    Yeh, Shu-Dan; True, John R

    2014-08-27

    Many adaptive phenotypes consist of combinations of simpler traits that act synergistically, such as morphological traits and the behaviors that use those traits. Genetic correlations between components of such combinatorial traits, in the form of pleiotropic or tightly linked genes, can in principle promote the evolution and maintenance of these traits. In the Oriental Drosophila melanogaster species group, male wing pigmentation shows phylogenetic correlations with male courtship behavior; species with male-specific apical wing melanin spots also exhibit male visual wing displays, whereas species lacking these spots generally lack the displays. In this study, we investigated the quantitative genetic basis of divergence in male wing spots and displays between D. elegans, which possesses both traits, and its sibling species D. gunungcola, which lacks them. We found that divergence in wing spot size is determined by at least three quantitative trait loci (QTL) and divergence in courtship score is determined by at least four QTL. On the autosomes, QTL locations for pigmentation and behavior were generally separate, but on the X chromosome two clusters of QTL were found affecting both wing pigmentation and courtship behavior. We also examined the genetic basis of divergence in three components of male courtship, wing display, circling, and body shaking. Each of these showed a distinct genetic architecture, with some QTL mapping to similar positions as QTL for overall courtship score. Pairwise tests for interactions between marker loci revealed evidence of epistasis between putative QTL for wing pigmentation but not those for courtship behavior. The clustering of X-linked QTL for male pigmentation and behavior is consistent with the concerted evolution of these traits and motivates fine-scale mapping studies to elucidate the nature of the contributing genetic factors in these intervals.

  12. Carotenoid composition of the flowers of Mimulus lewisii and related species: Implications regarding the prevalence and origin of two unique, allenic pigments.

    PubMed

    LaFountain, Amy M; Frank, Harry A; Yuan, Yao-Wu

    2015-05-01

    The genus Mimulus has been used as a model system in a wide range of ecological and evolutionary studies and contains many species with carotenoid pigmented flowers. However, the detailed carotenoid composition of these flowers has never been reported. In this paper the floral carotenoid composition of 11 Mimulus species are characterized using high-performance liquid chromatography, mass spectrometry and chemical methods with a particular focus on the genetic model species, Mimulus lewisii. M. lewisii flowers have five major carotenoids: antheraxanthin, violaxanthin, neoxanthin, and the unique allenic carotenoids, deepoxyneoxanthin and mimulaxanthin. This carotenoid profile is consistent with the expression levels of putative carotenoid biosynthetic genes in the M. lewisii flower. The other 10 species possess the same five carotenoids or a subset of these. Comparison of the carotenoid profiles among species in a phylogenetic context provides new insights into the biosynthesis and evolution of deepoxyneoxanthin and mimulaxanthin. This work also lays the foundation for future studies regarding transcriptional control of the carotenoid biosynthesis pathway in Mimulus flowers.

  13. Skin as a living coloring book: how epithelial cells create patterns of pigmentation.

    PubMed

    Weiner, Lorin; Fu, Wenyu; Chirico, William J; Brissette, Janice L

    2014-11-01

    The pigmentation of mammalian skin and hair develops through the interaction of two basic cell types - pigment donors and recipients. The pigment donors are melanocytes, which produce and distribute melanin through specialized structures. The pigment recipients are epithelial cells, which acquire melanin and put it to use, collectively yielding the pigmentation visible to the eye. This review will focus on the pigment recipients, the historically less understood cell type. These end-users of pigment are now known to exert a specialized control over the patterning of pigmentation, as they identify themselves as melanocyte targets, recruit pigment donors, and stimulate the transfer of melanin. As such, this review will discuss the evidence that the skin is like a coloring book: the pigment recipients create a 'picture,' a blueprint for pigmentation, which is colorless initially but outlines where pigment should be placed. Melanocytes then melanize the recipients and 'color in' the picture.

  14. [Synthesis of melanin pigments by Antarctic black yeast].

    PubMed

    Tashirev, A B; Romanovskaia, V A; Rokitko, P V; Matveeva, N A; Shilin, S O; Tashireva, A A

    2012-01-01

    Five strains of the black yeast similar to Exophiala nigra (Nadsoniela nigra), which we have isolated from the Antarctic biotopes, are studied. At cultivation in a periodic operation the maximum level of absolutely dry biomass in five tested strains constituted 3.2-7.8 g/l of medium, melanin pigment yield being 6-9% of absolutely dry mass of cells. Two highly productive strains have been selected. Pigments of the studied black yeast are water-insoluble, however dissolve in alkali and concentrated acids. The maximum absorption of the yeast pigments was in the range of 220 nm. The above-stated properties of pigments of the investigated yeast correspond to the description of melanin fractions of Nadsoniela nigra and some microscopic mushrooms. The water-soluble melanin-pigments have been obtained after the dialysis of alkaline solution of the pigment. UV-spectra and visible absorption spectra of water solution of melanin-pigments are almost identical to those of initial alkaline solutions. It is shown that the studied yeast are resistant to high concentrations of toxic metals (Hg2+, Cu2+, Co2+, Cr(VI) and Ni2+), and introduction of Co2+ into the cultivation medium leads to the increase of pigments synthesis.

  15. Internal pigment cells respond to external UV radiation in frogs.

    PubMed

    Franco-Belussi, Lilian; Nilsson Sköld, Helen; de Oliveira, Classius

    2016-05-01

    Fish and amphibians have pigment cells that generate colorful skins important for signaling, camouflage, thermoregulation and protection against ultraviolet radiation (UVR). However, many animals also have pigment cells inside their bodies, on their internal organs and membranes. In contrast to external pigmentation, internal pigmentation is remarkably little studied and its function is not well known. Here, we tested genotoxic effe