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Sample records for carotenoid crystal formation

  1. Carotenoid crystal formation in Arabidopsis and carrot roots caused by increased phytoene synthase protein levels.

    Directory of Open Access Journals (Sweden)

    Dirk Maass

    Full Text Available BACKGROUND: As the first pathway-specific enzyme in carotenoid biosynthesis, phytoene synthase (PSY is a prime regulatory target. This includes a number of biotechnological approaches that have successfully increased the carotenoid content in agronomically relevant non-green plant tissues through tissue-specific PSY overexpression. We investigated the differential effects of constitutive AtPSY overexpression in green and non-green cells of transgenic Arabidopsis lines. This revealed striking similarities to the situation found in orange carrot roots with respect to carotenoid amounts and sequestration mechanism. METHODOLOGY/PRINCIPAL FINDINGS: In Arabidopsis seedlings, carotenoid content remained unaffected by increased AtPSY levels although the protein was almost quantitatively imported into plastids, as shown by western blot analyses. In contrast, non-photosynthetic calli and roots overexpressing AtPSY accumulated carotenoids 10 and 100-fold above the corresponding wild-type tissues and contained 1800 and 500 microg carotenoids per g dry weight, respectively. This increase coincided with a change of the pattern of accumulated carotenoids, as xanthophylls decreased relative to beta-carotene and carotene intermediates accumulated. As shown by polarization microscopy, carotenoids were found deposited in crystals, similar to crystalline-type chromoplasts of non-green tissues present in several other taxa. In fact, orange-colored carrots showed a similar situation with increased PSY protein as well as carotenoid levels and accumulation patterns whereas wild white-rooted carrots were similar to Arabidopsis wild type roots in this respect. Initiation of carotenoid crystal formation by increased PSY protein amounts was further confirmed by overexpressing crtB, a bacterial PSY gene, in white carrots, resulting in increased carotenoid amounts deposited in crystals. CONCLUSIONS: The sequestration of carotenoids into crystals can be driven by the

  2. Composition and (in)homogeneity of carotenoid crystals in carrot cells revealed by high resolution Raman imaging

    Science.gov (United States)

    Roman, Maciej; Marzec, Katarzyna M.; Grzebelus, Ewa; Simon, Philipp W.; Baranska, Malgorzata; Baranski, Rafal

    2015-02-01

    Three categories of roots differing in both β/α-carotene ratio and in total carotenoid content were selected based on HPLC measurements: high α- and β-carotene (HαHβ), low α- and high β-carotene (LαHβ), and low α- and low β-carotene (LαLβ). Single carotenoid crystals present in the root cells were directly measured using high resolution Raman imaging technique with 532 nm and 488 nm lasers without compound extraction. Crystals of the HαHβ root had complex composition and consisted of β-carotene accompanied by α-carotene. In the LαHβ and LαLβ roots, measurements using 532 nm laser indicated the presence of β-carotene only, but measurements using 488 nm laser confirmed co-occurrence of xanthophylls, presumably lutein. Thus the results show that independently on carotenoid composition in the root, carotenoid crystals are composed of more than one compound. Individual spectra extracted from Raman maps every 0.2-1.0 μm had similar shapes in the 1500-1550 cm-1 region indicating that different carotenoid molecules were homogeneously distributed in the whole crystal volume. Additionally, amorphous carotenoids were identified and determined as composed of β-carotene molecules but they had a shifted the ν1 band probably due to the effect of bonding of other plant constituents like proteins or lipids.

  3. X-ray Crystal Structure and Time-resolved Spectroscopy of the Blue Carotenoid Violerythrin

    Czech Academy of Sciences Publication Activity Database

    Polívka, Tomáš; Frank, H.A.; Enriquez, M.M.; Niedzwiedzki, D.M.; Liaaen-Jensen, S.; Hemming, J.; Helliwell, J.R.; Helliwell, M.

    2010-01-01

    Roč. 114, č. 26 (2010), s. 8760-8769. ISSN 1520-6106 Institutional research plan: CEZ:AV0Z50510513 Keywords : carotenoids * excited states * spectroscopy Subject RIV: BO - Biophysics Impact factor: 3.603, year: 2010

  4. Engineering calcium oxalate crystal formation in Arabidopsis

    Science.gov (United States)

    Many plants accumulate crystals of calcium oxalate. Just how these crystals form remains unknown. To gain insight into the mechanisms regulating calcium oxalate crystal formation, a crystal engineering approach was initiated utilizing the non-crystal accumulating plant, Arabidopsis. The success of t...

  5. The Aromatic Carotenoids in the Organic Matter of the Devonian Domanic Formation (on example of Tatarstan territory)

    Science.gov (United States)

    Plotnikova, Irina; Nosova, Fidania; Ostroukhov, Sergey; Pronin, Nikita

    2015-04-01

    the paleo facies conditions of the Domanik formation -- black shales rich in organic matter. The use of aromatic carotenoids can restore paleo facies conditions of sedimentation of the Domanik strata, as well as a comparison of these with paleo tectonics and paleo geodynamics of the passive continental margin.

  6. Encapsulation of Carotenoids

    Science.gov (United States)

    Ribeiro, Henelyta S.; Schuchmann, Heike P.; Engel, Robert; Walz, Elke; Briviba, Karlis

    Carotenoids are natural pigments, which are synthesized by microorganisms and plants. More than 600 naturally occurring carotenoids have been found in the nature. The main sources of carotenoids are fruits, vegetables, leaves, peppers, and certain types of fishes, sea foods, and birds. Carotenoids may protect cells against photosensitization and work as light-absorbing pigments during photosynthesis. Some carotenoids may inhibit the destructive effect of reactive oxygen species. Due to the antioxidative properties of carotenoids, many investigations regarding their protective effects against cardiovascular diseases and certain types of cancers, as well as other degenerative illnesses, have been carried out in the last years (Briviba et al. 2004; Krinsky et al. 2004; Kirsh et al. 2006). A diet rich in carotenoids may also contribute to photoprotection against UV radiation (Stahl et al. 2006). In vitro studies have shown that carotenoids such as β-cryptoxanthin and lycopene stimulate bone formation and mineralization. The results may be related to prevention of osteoporosis (Kim et al. 2003; Yamaguchi and Uchiyama 2003; 2004; Yamaguchi et al. 2005).

  7. Carotenoid Distribution in Nature.

    Science.gov (United States)

    Alcaíno, Jennifer; Baeza, Marcelo; Cifuentes, Víctor

    2016-01-01

    Carotenoids are naturally occurring red, orange and yellow pigments that are synthesized by plants and some microorganisms and fulfill many important physiological functions. This chapter describes the distribution of carotenoid in microorganisms, including bacteria, archaea, microalgae, filamentous fungi and yeasts. We will also focus on their functional aspects and applications, such as their nutritional value, their benefits for human and animal health and their potential protection against free radicals. The central metabolic pathway leading to the synthesis of carotenoids is described as the three following principal steps: (i) the synthesis of isopentenyl pyrophosphate and the formation of dimethylallyl pyrophosphate, (ii) the synthesis of geranylgeranyl pyrophosphate and (iii) the synthesis of carotenoids per se, highlighting the differences that have been found in several carotenogenic organisms and providing an evolutionary perspective. Finally, as an example, the synthesis of the xanthophyll astaxanthin is discussed. PMID:27485217

  8. Root growth, secondary root formation and root gravitropism in carotenoid-deficient seedlings of Zea mays L

    Science.gov (United States)

    Ng, Y. K.; Moore, R.

    1985-01-01

    The effect of ABA on root growth, secondary-root formation and root gravitropism in seedlings of Zea mays was investigated by using Fluridone-treated seedlings and a viviparous mutant, both of which lack carotenoids and ABA. Primary roots of seedlings grown in the presence of Fluridone grew significantly slower than those of control (i.e. untreated) roots. Elongation of Fluridone-treated roots was inhibited significantly by the exogenous application of 1 mM ABA. Exogenous application of 1 micromole and 1 nmole ABA had either no effect or only a slight stimulatory effect on root elongation, depending on the method of application. The absence of ABA in Fluridone-treated plants was not an important factor in secondary-root formation in seedlings less than 9-10 d old. However, ABA may suppress secondary-root formation in older seedlings, since 11-d-old control seedlings had significantly fewer secondary roots than Fluridone-treated seedlings. Roots of Fluridone-treated and control seedlings were graviresponsive. Similar data were obtained for vp-9 mutants of Z. mays, which are phenotypically identical to Fluridone-treated seedlings. These results indicate that ABA is necessary for neither secondary-root formation nor for positive gravitropism by primary roots.

  9. Potential production of carotenoids from Neurospora

    Directory of Open Access Journals (Sweden)

    SRI PRIATNI

    2014-05-01

    Full Text Available Priatni S. 2014. Review: Potential production of carotenoids from Neurospora. Nusantara Bioscience 6: 63-68. Carotenoids are abundant and widely distributed in plants, animals and microorganisms. Commercial use of carotenoids competes between microorganisms and synthetic manufacture. Carotenoids production can be increased by improving the efficiency of carotenoid synthesis in microbes. Some of the cultural and environmental stimulants are positively affecting the carotenoid content of carotenogenic strains such as Neurospora. Neurospora is a fungus that exhibits the formation of spores and conidia, the part of the cell for carotenoids biosynthesis. The Indonesian traditional fermented food, red peanut cake or oncom, especially in West Java, is produced from legume residues of Neurospora sp. This fungus has been isolated and identified as Neurospora intermedia. In order to apply this pigment for food and cosmetic colorants, encapsulation techniques of carotenoids have been developed to improve its solubility and stability.

  10. Hydrogen Bond Formation between the Carotenoid Canthaxanthin and the Silanol Group on MCM-41 Surface.

    Science.gov (United States)

    Gao, Yunlong; Xu, Dayong; Kispert, Lowell D

    2015-08-20

    The formation of one or two hydrogen bonds (H-bonds) between canthaxanthin (CAN), a dye, and the silanol group(s) on the MCM-41 surface has been studied by density functional theory (DFT) calculations and calorimetric experiments. It was found that the formation of the H-bond(s) stabilized the CAN molecule more than its radical cation (CAN(•+)). The charge distribution, bond lengths, and the HOMO and LUMO energies of CAN are also affected. The formation of the H-bond(s) explains the lower photoinduced electron transfer efficiency of CAN imbedded in Cu-MCM-41 versus that for β-carotene (CAR) imbedded in Cu-MCM-41 where complex formation with Cu(2+) dominates. These calculations show that to achieve high electron transfer efficiency for a dye-sensitized solar cell, H-bonding between the dye and the host should be avoided. PMID:26230844

  11. Plastids and Carotenoid Accumulation.

    Science.gov (United States)

    Li, Li; Yuan, Hui; Zeng, Yunliu; Xu, Qiang

    2016-01-01

    Plastids are ubiquitously present in plants and are the organelles for carotenoid biosynthesis and storage. Based on their morphology and function, plastids are classified into various types, i.e. proplastids, etioplasts, chloroplasts, amyloplasts, and chromoplasts. All plastids, except proplastids, can synthesize carotenoids. However, plastid types have a profound effect on carotenoid accumulation and stability. In this chapter, we discuss carotenoid biosynthesis and regulation in various plastids with a focus on carotenoids in chromoplasts. Plastid transition related to carotenoid biosynthesis and the different capacity of various plastids to sequester carotenoids and the associated effect on carotenoid stability are described in light of carotenoid accumulation in plants. PMID:27485226

  12. Key to xenobiotic carotenoids

    OpenAIRE

    Hans-Richard Sliwka; Vassilia Partali

    2012-01-01

    A listing of carotenoids with heteroatoms (X = F, Cl, Br, I, Si, N, S, Se, Fe) directly attached to the carotenoid carbon skeleton has been compiled. The 178 listed carotenoids with C,H,X atoms demonstrate that the classical division of carotenoids into hydrocarbon carotenoids (C,H) and xanthophylls (C,H,O) has become obsolete.

  13. Glycal Formation in Crystals of Uridine Phosphorylase

    Energy Technology Data Exchange (ETDEWEB)

    Paul, Debamita; O’Leary, Sen E.; Rajashankar, Kanagalaghatta; Bu, Weiming; Toms, Angela; Settembre, Ethan C.; Sanders, Jennie M.; Begley, Tadhg P.; Ealick, Steven E. (Cornell); (TAM)

    2010-06-22

    Uridine phosphorylase is a key enzyme in the pyrimidine salvage pathway. This enzyme catalyzes the reversible phosphorolysis of uridine to uracil and ribose 1-phosphate (or 2{prime}-deoxyuridine to 2{prime}-deoxyribose 1-phosphate). Here we report the structure of hexameric Escherichia coli uridine phosphorylase treated with 5-fluorouridine and sulfate and dimeric bovine uridine phosphorylase treated with 5-fluoro-2{prime}-deoxyuridine or uridine, plus sulfate. In each case the electron density shows three separate species corresponding to the pyrimidine base, sulfate, and a ribosyl species, which can be modeled as a glycal. In the structures of the glycal complexes, the fluorouracil O2 atom is appropriately positioned to act as the base required for glycal formation via deprotonation at C2{prime}. Crystals of bovine uridine phosphorylase treated with 2{prime}-deoxyuridine and sulfate show intact nucleoside. NMR time course studies demonstrate that uridine phosphorylase can catalyze the hydrolysis of the fluorinated nucleosides in the absence of phosphate or sulfate, without the release of intermediates or enzyme inactivation. These results add a previously unencountered mechanistic motif to the body of information on glycal formation by enzymes catalyzing the cleavage of glycosyl bonds.

  14. Formation of Piroxicam Polymorphism in Solution Crystallization

    DEFF Research Database (Denmark)

    Bruun Hansen, Thomas; Qu, Haiyan

    2015-01-01

    Recently, new insights into crystallization prior to actual nucleation have shown interesting results for drugs showing differences in hydrogen bonding or orientation in various polymorphic forms. On the basis of this concept, piroxicam was chosen as a model compound because the two common forms, I...... and II, show hydrogen bonding between different parts of the molecules and differences in the orientation of molecules in the crystal lattice. The goal of this work is to explore how various methods of controlling polymorphism during production could be employed. The mechanisms behind the nucleation...... were also explored, and new insights into polymorphic control are documented and discussed. The crystal landscape was mapped for cooling crystallization of piroxicam from acetone/water mixtures (0.5 K/min) and for antisolvent crystallization from acetone with water as the antisolvent. Varying cooling...

  15. Carotenoids in Marine Animals

    Directory of Open Access Journals (Sweden)

    Takashi Maoka

    2011-02-01

    Full Text Available Marine animals contain various carotenoids that show structural diversity. These marine animals accumulate carotenoids from foods such as algae and other animals and modify them through metabolic reactions. Many of the carotenoids present in marine animals are metabolites of β-carotene, fucoxanthin, peridinin, diatoxanthin, alloxanthin, and astaxanthin, etc. Carotenoids found in these animals provide the food chain as well as metabolic pathways. In the present review, I will describe marine animal carotenoids from natural product chemistry, metabolism, food chain, and chemosystematic viewpoints, and also describe new structural carotenoids isolated from marine animals over the last decade.

  16. Formation of collimated beams behind the woodpile photonic crystal

    International Nuclear Information System (INIS)

    We experimentally observe formation of narrow laser beams behind the woodpile photonic crystal, when the beam remains well collimated in free propagation behind the crystal. We show that the collimation depends on the input laser beam's focusing conditions, and we interpret theoretically the observed effect by calculating the spatial dispersion of propagation eigenmodes and by numerical simulation of paraxial propagation model.

  17. Coherent spectroscopy and carotenoids

    Czech Academy of Sciences Publication Activity Database

    Niklas Christensson, N.; Chábera, P.; Pascher, T.; Dietzek, B.; Polívka, Tomáš; Yartsev, A.; Pullerits, T.

    Nové Hrady : Academic and University Center, 2008. s. 24. [ESF Workshop on Novel Methods in Exploring Carotenoid Excited State Dynamics. 21.09.2008-25.09.2008, Nové Hrady] Keywords : carotenoids * biophysics Subject RIV: BO - Biophysics

  18. Origin of Aggregate Formation in Antibody Crystal Suspensions Containing PEG.

    Science.gov (United States)

    Hildebrandt, Christian; Mathaes, Roman; Saedler, Rainer; Winter, Gerhard

    2016-03-01

    The crystalline state of proteins is deemed as a promising formulation platform for biopharmaceuticals. However, a stabilizing effect of protein crystal suspensions is controversially discussed. In fact, antibodies can display an increased aggregation and particle formation profile after the crystallization process compared with liquid or solid amorphous formulations. Nevertheless, studies regarding aggregate formation and its origin remain meager in literature. It was the aim of this study to investigate these aspects for a model IgG antibody (mAb1), which shows an increased aggregate formation after crystallization with polyethylene glycol. The presence of a dynamic equilibrium, a steady exchange of protein between the crystals and the supernatant, was demonstrated by replacing the supernatant with an identical but fluorescence-labeled protein solution and followed by confocal laser scanning microscopy. Aggregate formation was monitored by size exclusion high-pressure chromatography and flow cytometry. Constantly increasing aggregate levels were found for the crystal fraction and for the supernatant. For the later, markedly higher particle counts were detected. The labeled supernatant and the unlabeled protein crystals allowed a precise identification of the origin of the aggregates. The rising aggregate fractions of the crystals displayed high mean fluorescence intensities that elucidated their origin in the supernatant. PMID:26886344

  19. Carotenoids in Marine Animals

    OpenAIRE

    Takashi Maoka

    2011-01-01

    Marine animals contain various carotenoids that show structural diversity. These marine animals accumulate carotenoids from foods such as algae and other animals and modify them through metabolic reactions. Many of the carotenoids present in marine animals are metabolites of β-carotene, fucoxanthin, peridinin, diatoxanthin, alloxanthin, and astaxanthin, etc. Carotenoids found in these animals provide the food chain as well as metabolic pathways. In the present review, I will describe marine a...

  20. Hydrophilic Carotenoids: Recent Progress

    OpenAIRE

    Attila Agócs; József Deli; Veronika Nagy; Magdolna Háda

    2012-01-01

    Carotenoids are substantially hydrophobic antioxidants. Hydrophobicity is this context is rather a disadvantage, because their utilization in medicine as antioxidants or in food chemistry as colorants would require some water dispersibility for their effective uptake or use in many other ways. In the past 15 years several attempts were made to synthetize partially hydrophilic carotenoids. This review compiles the recently synthetized hydrophilic carotenoid derivatives.

  1. Role of nucleation of bile liquid crystal in gallstone formation

    Institute of Scientific and Technical Information of China (English)

    Hai-Ming Yang; Jie Wu; Jin-Yi Li; Lin Gu; Min-Fei Zhou

    2003-01-01

    AIM: To explore the role of bile liquid crystal in the process of gallbladder stone formation and to provide bases for preventing and treating cholelithiasis.METHODS: 46 guinea pigs, half males and half females,were randomly divided into control group and stone-causing group. Normal feed and stoneleading feed were used respectively to raise guinea pigs in the control group and stone-causing group. The guinea pigs were killed in three batches during the raising period. Under polarizing microscope, the pattern changes of bile liquid crystal in the gallbladder biles of the guinea pigs in the control group and stone-causing group were dynamicly observed respectively in single-blind trial.RESULTS: It was found that there were few crystals in the guinea pigs′biles of the control group, and their Malta cross was small and scattered, and existed in single form. With the increase of the feeding days, bile liquid crystals grew and Malta cross became bigger with their distribution densified, denser somewhere, but always existed in single form. While those of the stone-causing group had more bile liquid crystals, Malta cross was big and merged in strings.With the increase of the feeding days, bile liquid crystals grew in amount and strings of Malta cross increased and became bigger. The crosses in strings were arranged more and more regularly and they gradually changed into stone crystals.CONCLUSION: Formation of gallbladder stone is a process of nucleation from different substances, and the causing-stone gallbladder bile is a constantly supersaturated solution, and bile liquid crystal is a nucleation factor in the formation of gallbladder stones. The process of nucleation includes gathering, merging and phase-changing of bile liquid crystals.The process of gathering, merging of bile liquid crystal is the key to nucleation.

  2. Calcium Channels are Involved in Calcium Oxalate Crystal Formation in Specialized Cells of Pistia stratiotes L.

    OpenAIRE

    VOLK, GAYLE M.; GOSS, LENORA J.; FRANCESCHI, VINCENT R.

    2004-01-01

    • Background and Aims Pistia stratiotes produces large amounts of calcium (Ca) oxalate crystals in specialized cells called crystal idioblasts. The potential involvement of Ca2+ channels in Ca oxalate crystal formation by crystal idioblasts was investigated.

  3. Formation of collimated beams behind the woodpile photonic crystal

    OpenAIRE

    Trull Silvestre, José Francisco; Maigyte, Lina; Malinauskas, Mangirdas; Mizeikis, Vygantas; Juodkazis, Saulius; Cojocaru, Crina; Rutkauskas, Marius; Peckus, Martynas; Sirutkaitis, Valdas; Staliunas, Kestutis

    2011-01-01

    We experimentally observe formation of narrow laser beams behind the woodpile photonic crystal, when the beam remains well collimated in free propagation behind the crystal. We show that the collimation depends on the input laser beam’s focusing conditions, and we interpret theoretically the observed effect by calculating the spatial dispersion of propagation eigenmodes and by numerical simulation of paraxial propagation model. Peer Reviewed

  4. Crystal Structure Representations for Machine Learning Models of Formation Energies

    CERN Document Server

    Faber, Felix; von Lilienfeld, O Anatole; Armiento, Rickard

    2015-01-01

    We introduce and evaluate a set of feature vector representations of crystal structures for machine learning (ML) models of formation energies of solids. ML models of atomization energies of organic molecules have been successful using a Coulomb matrix representation of the molecule. We consider three ways to generalize such representations to periodic systems: (i) a matrix where each element is related to the Ewald sum of the electrostatic interaction between two different atoms in the unit cell repeated over the lattice; (ii) an extended Coulomb-like matrix that takes into account a number of neighboring unit cells; and (iii) an Ansatz that mimics the periodicity and the basic features of the elements in the Ewald sum matrix by using a sine function of the crystal coordinates of the atoms. The representations are compared for a Laplacian kernel with Manhattan norm, trained to reproduce formation energies using a data set of 3938 crystal structures obtained from the Materials Project. For training sets consi...

  5. Formation of Optical Solitons in Nonlinear Photonic Crystal Waveguides

    Institute of Scientific and Technical Information of China (English)

    兰胜; 陈雄文

    2004-01-01

    Relying on the huge group velocity dispersion available in photonic crystal (PC) waveguides, we observe the formation of both Bragg grating solitons and gap solitons in nonlinear PC waveguides in numericalexperiments. Also,we indicate the potential applications of optical solitons in optical limiting, optical delay, and pulse compression and the feasibility of observing optical solitons in practical experiments.

  6. Hydrophilic Carotenoids: Recent Progress

    Directory of Open Access Journals (Sweden)

    Attila Agócs

    2012-04-01

    Full Text Available Carotenoids are substantially hydrophobic antioxidants. Hydrophobicity is this context is rather a disadvantage, because their utilization in medicine as antioxidants or in food chemistry as colorants would require some water dispersibility for their effective uptake or use in many other ways. In the past 15 years several attempts were made to synthetize partially hydrophilic carotenoids. This review compiles the recently synthetized hydrophilic carotenoid derivatives.

  7. Defective urinary crystallization inhibition and urinary stone formation

    Directory of Open Access Journals (Sweden)

    Mauricio Carvalho

    2006-06-01

    Full Text Available INTRODUCTION: Nephrocalcin (NC is a glycoprotein produced in the kidney and inhibits calcium oxalate crystal formation. It has been separated into 4 isoforms (A, B, C, and D and found that (A + B are more abundant than (C + D in urine of healthy subjects, but the reverse is seen in human urine of kidney stone patients. To further examine the role of this protein in inhibition of urinary crystallization, nephrocalcin isoforms were purified from 2 genetically pure dog species. MATERIALS AND METHODS: We studied healthy Beagles, known to be non-stone forming dogs, and Mini-Schnauzers, known to be calcium oxalate stone formers. NC was isolated and purified from each group. Urinary biochemistry and calcium oxalate crystal growth inhibition were measured. RESULTS: Specific crystal growth inhibition activity was significantly higher in non-stone forming dogs (9.79 ± 2.25 in Beagles vs. 2.75 ± 1.34 of Mini-Schnauzers, p < 0.005. Dissociation constants toward calcium oxalate monohydrate were 10-fold different, with Beagles' isoforms being 10 times stronger inhibitors compare to those of Mini-Schnauzers'. Isoforms C + D of NC were the main isoforms isolated in stone-forming dogs. CONCLUSION: NC of these two species of dogs differently affects calcium oxalate crystallization and might have a role in determining ulterior urinary stone formation.

  8. Entropy-driven crystal formation on highly strained substrates

    KAUST Repository

    Savage, John R.

    2013-05-20

    In heteroepitaxy, lattice mismatch between the deposited material and the underlying surface strongly affects nucleation and growth processes. The effect of mismatch is well studied in atoms with growth kinetics typically dominated by bond formation with interaction lengths on the order of one lattice spacing. In contrast, less is understood about how mismatch affects crystallization of larger particles, such as globular proteins and nanoparticles, where interparticle interaction energies are often comparable to thermal fluctuations and are short ranged, extending only a fraction of the particle size. Here, using colloidal experiments and simulations, we find particles with short-range attractive interactions form crystals on isotropically strained lattices with spacings significantly larger than the interaction length scale. By measuring the free-energy cost of dimer formation on monolayers of increasing uniaxial strain, we show the underlying mismatched substrate mediates an entropy-driven attractive interaction extending well beyond the interaction length scale. Remarkably, because this interaction arises from thermal fluctuations, lowering temperature causes such substrate-mediated attractive crystals to dissolve. Such counterintuitive results underscore the crucial role of entropy in heteroepitaxy in this technologically important regime. Ultimately, this entropic component of lattice mismatched crystal growth could be used to develop unique methods for heterogeneous nucleation and growth of single crystals for applications ranging from protein crystallization to controlling the assembly of nanoparticles into ordered, functional superstructures. In particular, the construction of substrates with spatially modulated strain profiles would exploit this effect to direct self-assembly, whereby nucleation sites and resulting crystal morphology can be controlled directly through modifications of the substrate.

  9. Triplet excited state spectra and dynamics of carotenoids from the thermophilic purple photosynthetic bacterium Thermochromatium tepidum

    Energy Technology Data Exchange (ETDEWEB)

    Niedzwiedzki, Dariusz; Kobayashi, Masayuki; Blankenship, R. E.

    2011-01-13

    Light-harvesting complex 2 from the anoxygenic phototrophic purple bacterium Thermochromatium tepidum was purified and studied by steady-state absorption, fluorescence and flash photolysis spectroscopy. Steady-state absorption and fluorescence measurements show that carotenoids play a negligible role as supportive energy donors and transfer excitation to bacteriochlorophyll-a with low energy transfer efficiency of ~30%. HPLC analysis determined that the dominant carotenoids in the complex are rhodopin and spirilloxanthin. Carotenoid excited triplet state formation upon direct (carotenoid) or indirect (bacteriochlorophyll-a Q{sub x} band) excitation shows that carotenoid triplets are mostly localized on spirilloxanthin. In addition, no triplet excitation transfer between carotenoids was observed. Such specific carotenoid composition and spectroscopic results strongly suggest that this organism optimized carotenoid composition in the light-harvesting complex 2 in order to maximize photoprotective capabilities of carotenoids but subsequently drastically suppressed their supporting role in light-harvesting process.

  10. Carotenoid metabolism in plants

    Science.gov (United States)

    Carotenoids are mostly C40 terpenoids, a class of hydrocarbons that participate in various biological processes in plants, such as photosynthesis, photomorphogenesis, photoprotection, and development. Carotenoids also serve as precursors for two plant hormones and a diverse set of apocarotenoids. Th...

  11. Antioxidant effects of carotenoids

    NARCIS (Netherlands)

    Bast, A.; Haenen, G.R.M.M.; Berg, R. van den; Berg, H. van den

    1998-01-01

    Surprisingly, neither the precise pharmacological effect nor the toxicological profile is usually established for food components. Carotenoids are no exception in this regard. Only limited insight into the pharmacology and toxicology of carotenoids exists. It is known that the antioxidant action of

  12. Carotenoids in Microalgae.

    Science.gov (United States)

    Henríquez, Vitalia; Escobar, Carolina; Galarza, Janeth; Gimpel, Javier

    2016-01-01

    Carotenoids are a class of isoprenoids synthesized by all photosynthetic organisms as well as by some non-photosynthetic bacteria and fungi with broad applications in food, feed and cosmetics, and also in the nutraceutical and pharmaceutical industries. Microalgae represent an important source of high-value products, which include carotenoids, among others. Carotenoids play key roles in light harvesting and energy transfer during photosynthesis and in the protection of the photosynthetic apparatus against photooxidative damage. Carotenoids are generally divided into carotenes and xanthophyls, but accumulation in microalgae can also be classified as primary (essential for survival) and secondary (by exposure to specific stimuli).In this chapter, we outline the high value carotenoids produced by commercially important microalgae, their production pathways, the improved production rates that can be achieved by genetic engineering as well as their biotechnological applications. PMID:27485224

  13. Image formation by and wave propagation in a photonic crystal

    Science.gov (United States)

    Parimi, Patanjali; Vodo, Plarenta; Wentao, Lu; di Gennaro, Emiliano; Sridhar, Srinivas

    2004-03-01

    Negative refraction and imaging by a flat slab of a material are two of the important consequences of lefthanded electromagnetism. In our recent work we have demonstrated negative refraction and imaging by photonic crystals in the microwave frequency range [1]. The details of image formation are intriguing and urge its investigation. We have carried out microwave measurements in a parallel plate waveguide made of a pair of metallic plates. The Photonic crystal is made of alumina rods arranged on a square lattice such that the electric field is parallel to the axis of the rods. The detector is a dipole antenna which is inserted into the waveguide from outside. HP 8510C network analyzer is used to measure the complex transmission coefficient . The intensity maps of vs. probe position are obtained by scanning the probe using an x-y robot, both inside and outside the crystal. The results suggest Bloch wave propagation inside the crystal and that the image formation requires a better understanding than a simple ray diagram following geometric optics. [1] P. V. Parimi et al., Nature, 426, 404 (2003).

  14. Crystal Structure Representations for Machine Learning Models of Formation Energies

    OpenAIRE

    Faber, Felix; Lindmaa, Alexander; von Lilienfeld, O. Anatole; Armiento, Rickard

    2015-01-01

    We introduce and evaluate a set of feature vector representations of crystal structures for machine learning (ML) models of formation energies of solids. ML models of atomization energies of organic molecules have been successful using a Coulomb matrix representation of the molecule. We consider three ways to generalize such representations to periodic systems: (i) a matrix where each element is related to the Ewald sum of the electrostatic interaction between two different atoms in the unit ...

  15. Carotenoids and Photosynthesis.

    Science.gov (United States)

    Hashimoto, Hideki; Uragami, Chiasa; Cogdell, Richard J

    2016-01-01

    Carotenoids are ubiquitous and essential pigments in photosynthesis. They absorb in the blue-green region of the solar spectrum and transfer the absorbed energy to (bacterio-)chlorophylls, and so expand the wavelength range of light that is able to drive photosynthesis. This is an example of singlet-singlet energy transfer, and so carotenoids serve to enhance the overall efficiency of photosynthetic light reactions. Carotenoids also act to protect photosynthetic organisms from the harmful effects of excess exposure to light. Triplet-triplet energy transfer from chlorophylls to carotenoids plays a key role in this photoprotective reaction. In the light-harvesting pigment-protein complexes from purple photosynthetic bacteria and chlorophytes, carotenoids have an additional role of structural stabilization of those complexes. In this article we review what is currently known about how carotenoids discharge these functions. The molecular architecture of photosynthetic systems will be outlined first to provide a basis from which to describe carotenoid photochemistry, which underlies most of their important functions in photosynthesis. PMID:27485220

  16. Mineral matter crystallization and crack formation in tuyere coke

    Energy Technology Data Exchange (ETDEWEB)

    Stanislav Gornostayev; Jouko Haerkki [University of Oulu, Oulu (Finland). Laboratory of Process Metallurgy

    2006-05-15

    Polished and dry-cut sections of samples of tuyere coke were studied by scanning electron microscopy to reveal the mechanism of appearance, distribution and effects of aluminosilicate spherules and irregular segregations of slag and spinel crystals formed in the coke matrix. It was found that the formation of spherules and slag is not destructive with respect to the host coke matrix. On the contrary, the octahedral spinel crystals, which grow from the aluminosilicate spherules gradually expose {l_brace}1 1 1{r_brace} faces and edges and change the shape and possibly volume of the parental mineral matter. The sharp and straight edges probably cause cracks to appear in the coke matrix, leading to a weakening of its strength upon crystal growth. The proposed model for this crack formation probably reflects the negative role of some Al- and especially Mg-bearing minerals in the coal blends used for the production of coke, and partly reveals mineralogical insights into the negative influence of high ash basicity on coke strength. 11 refs., 6 figs., 1 tab.

  17. Formation of norisoprenoid flavor compounds in carrot (Daucus carota L.) roots: characterization of a cyclic-specific carotenoid cleavage dioxygenase 1 gene

    Science.gov (United States)

    Carotenoids are isoprenoid pigments that upon oxidative cleavage lead to the production of norisoprenoids that have profound effect on flavor and aromas of agricultural produce. The biosynthetic pathway to norisoprenoids in carrots (Daucus carota L.) is still widely unknown. We found that geranial i...

  18. ASTAXANTHIN: A POTENTIAL CAROTENOID

    OpenAIRE

    Jyotika Dhankhar et al.

    2012-01-01

    Astaxanthin, a member of the carotenoid family, is a dark-red pigment which is the main carotenoid found in the marine world of algae and aquatic animals. Astaxanthin, is present in many types of seafood, including salmon, trout, red sea bream, shrimp and lobster, as well as in birds such as flamingo and quail. Synthetic Astaxanthin dominates the world market but recent interest in natural sources of the pigment has increased substantially. Common sources of natural Astaxanthin, are the gree...

  19. A Unified Theory of Melting, Crystallization and Glass Formation

    DEFF Research Database (Denmark)

    Cotterill, R. M. J.; Jensen, F. J.; Damgaard Kristensen, W.;

    1975-01-01

    In recent years, dislocations have been involved in theories of melting, in models of the liquid state, and in calculations of the viscosity of glasses. Particularly noteworthy are the Mott-Gurney model of a liquid as a polycrystal with a grain size (i. e. a dislocation network size) of near......-atomic dimensions, and the demonstration by Kotze and Kuhlmann-Wilsdorf that the solid-liquid interfacial energy is proportional to the grain boundary energy for a number of elements. These developments suggest the possibility of a relatively simple picture of crystallization and glass formation. In the liquid...

  20. Dietary factors that affect carotenoid bioavailability

    NARCIS (Netherlands)

    Hof, van het K.

    1999-01-01

    Carotenoids are thought to contribute to the beneficial effects of increased vegetable consumption. To better understand the potential benefits of carotenoids, we investigated the bioavailability of carotenoids from vegetables and dietary factors which might influence carotenoid bioavailability.In a

  1. 类胡萝卜素对蛹虫草子实体形成的影响%Effect of carotenoids on the formation of Cordyceps militaris fruit body

    Institute of Scientific and Technical Information of China (English)

    胡久平; 周礼红; 赵永霞; 吴铄溟

    2013-01-01

    类胡萝卜素对蛹虫草子实体形成有很大影响.为了探讨类胡萝卜素与蛹虫草子实体形成的关系,选取三种典型菌落形态的蛹虫草菌株,研究其在光照黑暗交替条件下不同菌落形态和类胡萝卜紊含量对子实体形成的影响.采用酸热法和吸收光谱法提取测定类胡萝卜素含量.结果表明三类蛹虫草在沙氏平板上均有可形成子实体的菌株,说明形态与子实体形成无直接关系.类胡萝卜素含量在3000μg/g以下的菌株在沙氏培养基上无子实体形成,3000~3500μg/g有子实体形成平均为2个/cm2,3500~6500μg/g菌株子实体形成能力较强平均为7个/cm2,含量在6500μg/g以上菌株形成子实体平均在5个/cm2,全黑暗培养菌株未检测到类胡萝卜素,也无子实体形成.%Carotenoids are the key factors affecting the formation of fruit bodies of Cordyceps militaris. Three type strains Cordyceps militaris which had typical colony morphology were selected. The influence of conditions such as light and dark cycle, different colony morphology on the formation of the fruit body and contents of carotenoids was investigated. Carotenoids were extracted by hydrochloric acid(HCI) with heating (by boiling water) and detected by absorption spectroscopy. The result was that the strains had ability to product fruit bodies in three morphology differently, the formation of fruit body and colony morphology were not related. The fruit body could not be formed as the carotenoid content of less than 3000μg/g. However,the rate of formation of fruit body was 2,7,5 each square centimetre, as the carotenoids contents of 3000~3500μg/g, 3500~6500μg/g, more than 6500μg/g, respectively. On the contrary, neither the fruit body and the carotenoids could be detected under the dark condition.

  2. Biologically active polymers from spontaneous carotenoid oxidation: a new frontier in carotenoid activity.

    Directory of Open Access Journals (Sweden)

    James B Johnston

    Full Text Available In animals carotenoids show biological activity unrelated to vitamin A that has been considered to arise directly from the behavior of the parent compound, particularly as an antioxidant. However, the very property that confers antioxidant activity on some carotenoids in plants also confers susceptibility to oxidative transformation. As an alternative, it has been suggested that carotenoid oxidative breakdown or metabolic products could be the actual agents of activity in animals. However, an important and neglected aspect of the behavior of the highly unsaturated carotenoids is their potential to undergo addition of oxygen to form copolymers. Recently we reported that spontaneous oxidation of ß-carotene transforms it into a product dominated by ß-carotene-oxygen copolymers. We now report that the polymeric product is biologically active. Results suggest an overall ability to prime innate immune function to more rapidly respond to subsequent microbial challenges. An underlying structural resemblance to sporopollenin, found in the outer shell of spores and pollen, may allow the polymer to modulate innate immune responses through interactions with the pattern recognition receptor system. Oxygen copolymer formation appears common to all carotenoids, is anticipated to be widespread, and the products may contribute to the health benefits of carotenoid-rich fruits and vegetables.

  3. Formation of carbon crystals from polymers using electron irradiation

    International Nuclear Information System (INIS)

    Polymers consist mainly of carbon and other atoms such as hydrogen, oxygen, fluorine and etc. Because of the gas evolution during irradiation, polymer is converted into the carbon-rich materials un deer electron as well as ion irradiation. Ions have more heavy mass than electron, so it could be easy to generate the defects through the collision between ion and polymer. But electrons are not nearly affected the formation of defects due to their light mass. Thus the crystals could be formed from the electron irradiated polymer. PMMA and PE, which are degraded and cross-linked upon electron beam irradiation respectively, are irradiated by electrons of low energy and high fluence in the vacuum. In order to investigate the properties of irradiated polymers changed by electron irradiation, Raman spectrometer, nanoidentor, X-ray photoelectron spectroscopy (XPS) and transmission electron microscope (TEM) are used. It reveals that the characteristic Raman bands of starting material are lost upon electron beam irradiation and the one-phonon bands near 1350 cm-1 (D line) and 1580 cm-1 (G line) of amorphous carbon appeared. Also the content of the sp2- and sp3 -bonded carbon which are related with electronic and mechanical properties in an amorphous carbon respectively, increases with fluence. And the surface hardness in the irradiated polymers increases as fluence increases in spite of the fact that PMMA has degrading property under irradiation especially. In the TEM observation, their diffraction patterns and high resolution lattice image show the formation of carbon crystals from polymer

  4. Diagenetic Crystal Growth in the Murray Formation, Gale Crater, Mars

    Science.gov (United States)

    Kah, L. C.; Kronyak, R. E.; Ming, D. W.; Grotzinger, J. P.; Schieber, J.; Sumner, D. Y.; Edgett, K. S.

    2015-01-01

    The Pahrump region (Gale Crater, Mars) marks a critical transition between sedimentary environments dominated by alluvial-to-fluvial materials associated with the Gale crater rim, and depositional environments fundamentally linked to the crater's central mound, Mount Sharp. At Pahrump, the Murray formation consists of an approximately 14-meter thick succession dominated by massive to finely laminated mudstone with occasional interbeds of cross-bedded sandstone, and is best interpreted as a dominantly lacustrine environment containing tongues of prograding fluvial material. Murray formation mudstones contain abundant evidence for early diagenetic mineral precipitation and its subsequent removal by later diagenetic processes. Lenticular mineral growth is particularly common within lacustrine mudstone deposits at the Pahrump locality. High-resolution MAHLI images taken by the Curiosity rover permit detailed morphological and spatial analysis of these features. Millimeter-scale lenticular features occur in massive to well-laminated mudstone lithologies and are interpreted as pseudomorphs after calcium sulfate. The distribution and orientation of lenticular features suggests deposition at or near the sediment-water (or sediment-air) interface. Retention of chemical signals similar to host rock suggests that original precipitation was likely poikilotopic, incorporating substantial amounts of the primary matrix. Although poikilotopic crystal growth is common in burial environments, it also occurs during early diagenetic crystal growth within unlithified sediment where high rates of crystal growth are common. Loss of original calcium sulfate mineralogy suggests dissolution by mildly acidic, later-diagenetic fluids. As with lenticular voids observed at Meridiani by the Opportunity Rover, these features indicate that calcium sulfate deposition may have been widespread on early Mars; dissolution of depositional and early diagenetic minerals is a likely source for both calcium

  5. On the role of labile oxocomplexes in carotenoids antioxidant activity

    International Nuclear Information System (INIS)

    Early stages of the interaction of carotenoids and molecular oxygen are studied and role of its interaction in the processes responsible for radiation resistance of carotenoids, superoxide dismutase activity to the singlet oxygen quenching. Ethanol and aqueous solutions of the carotenoids (phosphate buffer with pH 7.5) were exposed to accelerated electron flux at pulse regime and dose rate (0.7-2.0)x1017 eV/ml imp in the dark and in case of combined effect of radiation and light. It is concluded that at the early stages of processes with the participation of carotenoids the formation of reversible complexes with charge transfer plays the important role. Properties and reaction capability of these complexes are determined by the peculiarities in chemical structure of carotenoid molecules

  6. Mechanistic aspects of carotenoid biosynthesis

    KAUST Repository

    Moïse, Alexander R.

    2014-01-08

    Carotenoid synthesis is based on the analysis of the phenotype of several mutant strains of tomato lacking carotenoid synthetic genes. Carotenoids are tetraterpenes derived through the condensation of the five-carbon (C5) universal isoprenoid precursors isopentenyl diphosphate (IPP) and dimethylallyl diphosphate (DMAPP). A recently developed concept that could explain the role of the poly-cis pathway in carotenoid synthesis is that the intermediates of this pathway have additional physiological roles that extend beyond serving as precursors of lycopene. This concept is based on the analysis of the phenotype of several mutant strains of tomato lacking carotenoid synthetic genes. The feedback regulation of early carotenoid synthetic genes in response to a block in upstream metabolism represents a paradigm shift in our understanding of the mechanism and regulation of carotenoid synthesis and of metabolic regulation in general. The molecular details of a signaling pathway that regulates carotenogenesis in response to the levels of carotenoid precursors are still unclear.

  7. Investigation of defects formation on different stages of sapphire crystals growth

    International Nuclear Information System (INIS)

    The mathematical simulations and calculations allow to estimate the large number of factors influence on crystals growth and quality and to determine the main cause of the defect structures formation in the solid phase. The research results allow making the quantity estimation of defects formation in sapphire crystals. The simulation results can help to define defect formation zones and can be used for recommendations about crystals quality improvement

  8. Environmental factors affect calcium oxalate crystals formation in tradescantia pallida (commelinaceae)

    International Nuclear Information System (INIS)

    Tradescantia pallida has major types of calcium oxalate crystals i.e., raphide, prismatic, and druse that are widely distributed within collenchmya, cortical and vascular parenchyma in the stem. However, mechanisms involved in crystal formation in response to stress conditions are not properly understood. In order to evaluate formation of these crystals in response to heavy metals i.e., mercury, sections of control (untreated) and mercury treated plants were prepared, stained with toluidine blue and photographed (infinity software). Mercuric chloride at high doses increased all types of crystals as compared with low doses; suggesting that mercury stress increases metabolic activities of Tradescantia that produce crystals may be, in order to defend themselves. So in T. pallida, crystal formation is influenced by mercury stress that increased raphide and prismatic crystals in the treated plants. However, biochemical aspects involved in oxalic acid formation and release of Ca by Hg need to be explored more. (author)

  9. Numerical computations of facetted pattern formation in snow crystal growth

    OpenAIRE

    Barrett, John W.; Garcke, Harald; Nürnberg, Robert

    2012-01-01

    Facetted growth of snow crystals leads to a rich diversity of forms, and exhibits a remarkable sixfold symmetry. Snow crystal structures result from diffusion limited crystal growth in the presence of anisotropic surface energy and anisotropic attachment kinetics. It is by now well understood that the morphological stability of ice crystals strongly depends on supersaturation, crystal size and temperature. Until very recently it was very difficult to perform numerical simulations of this h...

  10. Diffusion model of the formation of growth microdefects: A new approach to defect formation in crystals (Review)

    Science.gov (United States)

    Talanin, V. I.; Talanin, I. E.

    2016-03-01

    Theoretical studies of defect formation in semiconductor silicon play an important role in the creation of breakthrough ideas for next-generation technologies. A brief comparative analysis of modern theoretical approaches to the description of interaction of point defects and formation of the initial defect structure of dislocation-free silicon single crystals has been carried out. Foundations of the diffusion model of the formation of structural imperfections during the silicon growth have been presented. It has been shown that the diffusion model is based on high-temperature precipitation of impurities. The model of high-temperature precipitation of impurities describes processes of nucleation, growth, and coalescence of impurities during cooling of a crystal from 1683 to 300 K. It has been demonstrated that the diffusion model of defect formation provides a unified approach to the formation of a defect structure beginning with the crystal growth to the production of devices. The possibilities of using the diffusion model of defect formation for other semiconductor crystals and metals have been discussed. It has been shown that the diffusion model of defect formation is a platform for multifunctional solution of many key problems in modern solid state physics. Fundamentals of practical application of the diffusion model for engineering of defects in crystals with modern information technologies have been considered. An algorithm has been proposed for the calculation and analysis of a defect structure of crystals.

  11. Photoinduced Surface Relief Grating Formation for a Single Crystal of 4-Aminoazobenzene

    Directory of Open Access Journals (Sweden)

    Hideyuki Nakano

    2010-03-01

    Full Text Available Photoinduced surface relief grating (SRG formation for a single crystal of 4-aminoazobenzene was investigated. It was found that SRG could be inscribed on the (001 surface of the crystal, which might suggest that the photoinduced SRG formation is a general phenomenon observed for single crystals of azobenzene-based molecules as well as for azobenzene-based amorphous systems. In addition, the dependences of the SRG formation upon the orientation of the sample crystal and upon the polarization of the writing beams were found to be different from those observed for previously reported crystalline systems.

  12. Monocrystalline structure formation of doped perfect silicon crystals

    International Nuclear Information System (INIS)

    In this paper we consider perfect doped silicon single crystals growth. Special features of anodic etching of n- and p-type single crystals has been revealed. An impact of seed orientation on dislocation and defect structure evolution in crystal on different growth stages has been found. Influence of heat treatment on phase-structural condition of single crystals and nonequilibrium carrier lifetime has been determined

  13. Formation of liquid inclusion induced light scatter in KDP (DKDP) crystals

    Institute of Scientific and Technical Information of China (English)

    孙洵; 孙大亮; 许心光; 王正平; 付有君; 王圣来; 曾红; 李毅平; 于锡玲; 高樟寿

    2001-01-01

    We describe in this paper the formation of liquid inclusion induced light scatter in potassium dihydrogen phosphate (KDP) crystal and deuterated potassium dihydrogen phosphate (DKDP) crystals. The measurement has been done with an atomic force microscope (AFM). The mechanism of formation of liquid inclusion scatter has been proposed and the effect of super-saturation discussed.

  14. The Or gene enhances carotenoid accumulation and stability during post-harvest storage of potato tubers.

    Science.gov (United States)

    Li, Li; Yang, Yong; Xu, Qiang; Owsiany, Katherine; Welsch, Ralf; Chitchumroonchokchai, Chureeporn; Lu, Shan; Van Eck, Joyce; Deng, Xiu-Xin; Failla, Mark; Thannhauser, Theodore W

    2012-03-01

    Provitamin A carotenoids in staple crops are not very stable during storage and their loss compromises nutritional quality. To elucidate the fundamental mechanisms underlying carotenoid accumulation and stability, we investigated transgenic potato tubers that expressed the cauliflower Orange (Or) gene. We found that the Or transgene not only promoted retention of β-carotene level, but also continuously stimulated its accumulation during 5 months of cold storage. In contrast, no increased levels of carotenoids were observed in the tubers of vector-only controls or a yellow-flesh variety during the same period of storage. The increased carotenoid accumulation was found to be associated with the formation of lipoprotein-carotenoid sequestering structures, as well as with the enhanced abundance of phytoene synthase, a key enzyme in the carotenoid biosynthetic pathway. Furthermore, the provitamin A carotenoids stored were shown to be stable during simulated digestion and accessible for uptake by human intestinal absorptive cells. Proteomic analysis identified three major functional groups of proteins (i.e. heat shock proteins, glutathione-S-transferases, and carbohydrate metabolic proteins) that are potentially important in the Or-regulated carotenoid accumulation. Our results show that regulation of carotenoid sequestration capacity is an important mechanism by which carotenoid stability is regulated. Our findings suggest that induction of a proper sink structure formation in staple crops may provide the crops with a unique ability to promote and/or stabilize provitamin A accumulation during plant growth and post-harvest storage. PMID:22155949

  15. Organic crystal-binding peptides: morphology control and one-pot formation of protein-displaying organic crystals

    Science.gov (United States)

    Niide, Teppei; Ozawa, Kyohei; Nakazawa, Hikaru; Oliveira, Daniel; Kasai, Hitoshi; Onodera, Mari; Asano, Ryutaro; Kumagai, Izumi; Umetsu, Mitsuo

    2015-11-01

    Crystalline assemblies of fluorescent molecules have different functional properties than the constituent monomers, as well as unique optical characteristics that depend on the structure, size, and morphological homogeneity of the crystal particles. In this study, we selected peptides with affinity for the surface of perylene crystal particles by exposing a peptide-displaying phage library in aqueous solution to perylene crystals, eluting the surface-bound phages by means of acidic desorption or liquid-liquid extraction, and amplifying the obtained phages in Escherichia coli. One of the perylene-binding peptides, PeryBPb1: VQHNTKYSVVIR, selected by this biopanning procedure induced perylene molecules to form homogenous planar crystal nanoparticles by means of a poor solvent method, and fusion of the peptide to a fluorescent protein enabled one-pot formation of protein-immobilized crystalline nanoparticles. The nanoparticles were well-dispersed in aqueous solution, and Förster resonance energy transfer from the perylene crystals to the fluorescent protein was observed. Our results show that the crystal-binding peptide could be used for simultaneous control of perylene crystal morphology and dispersion and protein immobilization on the crystals.Crystalline assemblies of fluorescent molecules have different functional properties than the constituent monomers, as well as unique optical characteristics that depend on the structure, size, and morphological homogeneity of the crystal particles. In this study, we selected peptides with affinity for the surface of perylene crystal particles by exposing a peptide-displaying phage library in aqueous solution to perylene crystals, eluting the surface-bound phages by means of acidic desorption or liquid-liquid extraction, and amplifying the obtained phages in Escherichia coli. One of the perylene-binding peptides, PeryBPb1: VQHNTKYSVVIR, selected by this biopanning procedure induced perylene molecules to form homogenous planar

  16. Formation of co-crystals: Kinetic and thermodynamic aspects

    Science.gov (United States)

    Gagnière, E.; Mangin, D.; Puel, F.; Rivoire, A.; Monnier, O.; Garcia, E.; Klein, J. P.

    2009-04-01

    Co-crystallisation is a recent method of great interest for the pharmaceutical industry, since pharmaceutical co-crystals represent useful materials for drug products. In this study, an active pharmaceutical ingredient (carbamazepine (CBZ)) co-crystallized with a vitamin (nicotinamide (NCT)) was chosen as a model substance. This work was focused on the construction of a phase diagram for the system CBZ/NCT, split in six domains for kinetic reasons (the different solid phases which might appear during the crystallisation) and in four domains according to thermodynamic aspects (the stable final phase obtained). Although co-crystals are not ionic compounds, the supersaturation of co-crystals can be evaluated by considering the solubility product. Batch crystallisation operations were carried out in a stirred vessel equipped with an in situ video probe. This latter device was a powerful analysis tool to monitor the CBZ/NCT co-crystals and single CBZ crystals since these two crystalline phases grown in ethanol exhibited needle and platelet habits. As concerns kinetics, the different solid phases which might appear during the experiments were observed and competed against each others. In accordance with thermodynamics, the stable solid form was obtained at the end of the operation. Finally some preliminary results indicate that the nucleation of co-crystals may be favoured by the presence of CBZ crystals. Epitaxial relationships between CBZ/NCT co-crystals and CBZ crystals were suspected.

  17. The formation of crystals in glasses containing rare earth oxides

    International Nuclear Information System (INIS)

    Korean spent nuclear fuel will reach the capacity of the available temporary storage by 2016. Pyroprocessing and direct disposal seems to be an alternative way to manage and reuse spent nuclear fuel while avoiding the wet reprocessing technology. Pyroprocessing produces several wastes streams, including metals, salts, and rare earths, which must be converted into stabilized form. A suitable form for rare earth immobilization is borosilicate glass. The borosilicate glass form exhibits excellent durability, allows a high waste loading, and is easy to process. In this work, we combined the rare earths waste of composition (in wt%) 39.2Nd2O3–22.7CeO2–11.7La2O3–10.9PrO2–1.3Eu2O3–1.3Gd2O3–8.1Sm2O3–4.8Y2O3 with a baseline glass of composition 60.2SiO2–16.0B2O3–12.6Na2O–3.8Al2O3–5.7CaO–1.7ZrO2. Crystallization in waste glasses occurs as the waste loading increases. It may produce complicate glass processing and affect the product quality. To study crystal formation, we initially made glasses containing 5%, 10% and 15% of La2O3 and then glasses with 5%, 10% and 15% of the complete rare earth mix. Samples were heat-treated for 24 hours at temperatures 800°C to 1150°C in 50°C increments. Quenched samples were analyzed using an optical microscope, scanning electron microscope with energy dispersive spectroscopy, and x-ray diffraction. Stillwellite (LaBSiO5) and oxyapatite (Ca2La8Si6O26) were found in glasses containing La2O3, while oxyapatite (Ca2La8Si6O26 and NaNd9Si6O26) precipitated in glasses with additions of mixed rare earths. The liquidus temperature (TL) of the glasses containing 5%, 10% and 15% La2O3 were 800°C, 959°C and 986°C, respectively; while TL was 825°C, 1059°C and 1267°C for glasses with 5%, 10% and 15% addition of mixed rare earth oxides. The component coefficients TB2O3, TSiO2, TCaO, and TRE2O3 were also evaluated using a recently published study

  18. Carotenoid dynamics in Atlantic salmon

    OpenAIRE

    Omholt Stig W; Våge Dag; Øyehaug Leiv; Rajasingh Hannah

    2006-01-01

    Abstract Background Carotenoids are pigment molecules produced mainly in plants and heavily exploited by a wide range of organisms higher up in the food-chain. The fundamental processes regulating how carotenoids are absorbed and metabolized in vertebrates are still not fully understood. We try to further this understanding here by presenting a dynamic ODE (ordinary differential equation) model to describe and analyse the uptake, deposition, and utilization of a carotenoid at the whole-organi...

  19. Classical crystal formation of dipoles in two dimensions

    DEFF Research Database (Denmark)

    Hansen, Kenneth Christian Klochmann; Fedorov, D. V.; Jensen, A. S.; Zinner, N. T.

    2015-01-01

    We consider a two-dimensional layer of dipolar particles in the regime of strong dipole moments. Here we can describe the system using classical methods and determine the crystal structure that minimizes the total energy. The dipoles are assumed to be aligned by an external field and we consider......, i.e. a striped configuration. In addition to calculating the crystal unit cell, we also consider the phonon spectrum and the speed of sound. As the orientation changes away from perpendicular the phonon spectrum develops local minima that are a result of the deformation to the crystal structure....

  20. How carotenoids protect bacterial photosynthesis.

    OpenAIRE

    Cogdell, R J; Howard, T. D.; Bittl, R.; Schlodder, E; Geisenheimer, I; Lubitz, W.

    2000-01-01

    The essential function of carotenoids in photosynthesis is to act as photoprotective agents, preventing chlorophylls and bacteriochlorophylls from sensitizing harmful photodestructive reactions in the presence of oxygen. Based upon recent structural studies on reaction centres and antenna complexes from purple photosynthetic bacteria, the detailed organization of the carotenoids is described. Then with specific reference to bacterial antenna complexes the details of the photoprotective role, ...

  1. Vacancy formation energy in the quantal crystals of the two helium isotopes

    International Nuclear Information System (INIS)

    We derived a simple expression for the vacancy formation energy in a quantual crystal near melting in terms of its Lindemann parameter and of the density response of its liquid near freezing. Numerical illustrations are given for vacancies in 4He and 3He crystals. (author). 19 refs, 1 fig., 1 tab

  2. Formation of temperature fields in doped anisotropic crystals under spatially inhomogeneous light beams passing through them

    Energy Technology Data Exchange (ETDEWEB)

    Zaitseva, E. V.; Markelov, A. S.; Trushin, V. N., E-mail: trushin@phys.unn.ru; Chuprunov, E. V. [Nizhni Novgorod State University (Russian Federation)

    2013-12-15

    The features of formation of thermal fields in potassium dihydrophosphate crystal doped with potassium permanganate under a 532-nm laser beam passing through it have been investigated. Data on the influence of birefringence on the temperature distribution in an anisotropic crystal whose surface is illuminated by a spatially modulated light beam are presented.

  3. Formation of temperature fields in doped anisotropic crystals under spatially inhomogeneous light beams passing through them

    Science.gov (United States)

    Zaitseva, E. V.; Markelov, A. S.; Trushin, V. N.; Chuprunov, E. V.

    2013-12-01

    The features of formation of thermal fields in potassium dihydrophosphate crystal doped with potassium permanganate under a 532-nm laser beam passing through it have been investigated. Data on the influence of birefringence on the temperature distribution in an anisotropic crystal whose surface is illuminated by a spatially modulated light beam are presented.

  4. The role of oxygen containing impurities in defects formation in cesium halide crystals

    Science.gov (United States)

    Hud, I.; Garapyn, I.; Pavlyk, B.

    2003-01-01

    The dependence of defect formation efficiency in CsI single crystals both on the type of oxygen containing impurities and the value of the absorbed irradiation dose was studied. Correlative results were obtained under investigation by methods of ionic thermocurrent (ITC), thermostimulated exoemission (TSEE), electrical conductivity and optical spectroscopy. The peculiarities of defect formation in gamma-irradiated CsI-CO3(SO4, OH) and X-irradiated CsI-OH single crystals are discussed.

  5. Photorefractive grating formation in piezoelectric La3Ga5SiO14:Pr3+ crystals

    DEFF Research Database (Denmark)

    Dam-Hansen, C.; Johansen, P.M.; Fridkin, V.M.

    1996-01-01

    Photorefractive grating formation and erasure in piezoelectric crystals of La3Ga5SiO14:Pr3+ are presented. The specific photoconductivity and the photorefractive sensitivity are determined. The polarization dependence of the grating formation due to the bulk photovoltaic effect is shown and compa......Photorefractive grating formation and erasure in piezoelectric crystals of La3Ga5SiO14:Pr3+ are presented. The specific photoconductivity and the photorefractive sensitivity are determined. The polarization dependence of the grating formation due to the bulk photovoltaic effect is shown...

  6. ASTAXANTHIN: A POTENTIAL CAROTENOID

    Directory of Open Access Journals (Sweden)

    Jyotika Dhankhar et al.

    2012-05-01

    Full Text Available Astaxanthin, a member of the carotenoid family, is a dark-red pigment which is the main carotenoid found in the marine world of algae and aquatic animals. Astaxanthin, is present in many types of seafood, including salmon, trout, red sea bream, shrimp and lobster, as well as in birds such as flamingo and quail. Synthetic Astaxanthin dominates the world market but recent interest in natural sources of the pigment has increased substantially. Common sources of natural Astaxanthin, are the green algae haematococcus pluvialis, the red yeast, Phaffia rhodozyma, as well as crustacean byproducts. Astaxanthin possesses unusual antioxidant property which has caused a surge in the nutraceutical market of the encapsulated products. Numerous studies have shown that astaxanthin has potential health-promoting effects in the prevention and treatment of various diseases, such as cancers, chronic inflammatory diseases, metabolic syndrome, diabetes, diabetic nephropathy, cardiovascular diseases, gastrointestinal diseases, liver diseases, neurodegenerative diseases, eye diseases, skin diseases, exercise-induced fatigue, male infertility, and renal failure. In this article, the currently available scientific literature regarding the most significant activities of astaxanthin is reviewed.

  7. Formation Enthalpy Calculation of Oxygen Vacancy Defect in Doped Lithium Niobate Crystals

    Institute of Scientific and Technical Information of China (English)

    QIANG Liang-sheng; LI Yao; TANG Dong-yan; XU Chong-quan; WEI Yong-de

    2004-01-01

    The relationship between temperature and oxygen vacancy concentration is deduced in this paper. Based on the data of thermal weight-loss experiment, the formation enthalpies of congruent and several doped LN crystals have been calculated. It was found that the formation enthalpy of oxygen vacancies can be decreased evidently by doping valence-changeable ions. The experimental results were discussed and a new reduction process of the photorefractive LN crystal at a relatively low temperature was proposed, and the reduced crystals showed a good effect in practical use.

  8. Carotenoid Biosynthesis in Daucus carota.

    Science.gov (United States)

    Simpson, Kevin; Cerda, Ariel; Stange, Claudia

    2016-01-01

    Carrot (Daucus carota) is one of the most important vegetable cultivated worldwide and the main source of dietary provitamin A. Contrary to other plants, almost all carrot varieties accumulate massive amounts of carotenoids in the root, resulting in a wide variety of colors, including those with purple, yellow, white, red and orange roots. During the first weeks of development the root, grown in darkness, is thin and pale and devoid of carotenoids. At the second month, the thickening of the root and the accumulation of carotenoids begins, and it reaches its highest level at 3 months of development. This normal root thickening and carotenoid accumulation can be completely altered when roots are grown in light, in which chromoplasts differentiation is redirected to chloroplasts development in accordance with an altered carotenoid profile. Here we discuss the current evidence on the biosynthesis of carotenoid in carrot roots in response to environmental cues that has contributed to our understanding of the mechanism that regulates the accumulation of carotenoids, as well as the carotenogenic gene expression and root development in D. carota. PMID:27485223

  9. Formation of a crystallization courtyard in eutectic systems and crystal growth

    Science.gov (United States)

    Gurin, V. N.; Osipov, V. N.; Derkachenko, L. I.; Korchunov, B. N.; Popova, T. B.

    2014-03-01

    The so-called crystallization courtyard is investigated that forms in processes of mass crystallization around the Ge and Si crystals and their solid solutions (Ge+Si) during cooling of hypereutectic alloys in the Ge-Al, Si-Al, and (Ge+Si)-Al eutectic systems. For the first time, data on the composition and microhardness of this crystallization courtyard are given and its role is shown as a stopper of cracking in an Al-(Ge,Si) system during rapid cooling after the heating system is turned off. For the first time, it is suggested that a crystallization courtyard forms in all hypereutectic systems (including every system in which the amount of the taken solvent does not correspond to the eutectic point).

  10. Food Predictors of Plasma Carotenoids

    Directory of Open Access Journals (Sweden)

    Sara J. Hendrickson

    2013-10-01

    Full Text Available Empirical prediction models that weight food frequency questionnaire (FFQ food items by their relation to nutrient biomarker concentrations may estimate nutrient exposure better than nutrient intakes derived from food composition databases. Carotenoids may especially benefit because contributing foods vary in bioavailability and assessment validity. Our objective was to develop empirical prediction models for the major plasma carotenoids and total carotenoids and evaluate their validity compared with dietary intakes calculated from standard food composition tables. 4180 nonsmoking women in the Nurses’ Health Study (NHS blood subcohort with previously measured plasma carotenoids were randomly divided into training (n = 2787 and testing (n = 1393 subsets. Empirical prediction models were developed in the training subset by stepwise selection from foods contributing ≥0.5% to intake of the relevant carotenoid. Spearman correlations between predicted and measured plasma concentrations were compared to Spearman correlations between dietary intake and measured plasma concentrations for each carotenoid. Three to 12 foods were selected for the α-carotene, β-carotene, β-cryptoxanthin, lutein/zeaxanthin, lycopene, and total carotenoids prediction models. In the testing subset, Spearman correlations with measured plasma concentrations for the calculated dietary intakes and predicted plasma concentrations, respectively, were 0.31 and 0.37 for α-carotene, 0.29 and 0.31 for β-carotene, 0.36 and 0.41 for β-cryptoxanthin, 0.28 and 0.31 for lutein/zeaxanthin, 0.22 and 0.23 for lycopene, and 0.22 and 0.27 for total carotenoids. Empirical prediction models may modestly improve assessment of some carotenoids, particularly α-carotene and β-cryptoxanthin.

  11. Wave propagation in single column woodpile phononic crystals: Formation of tunable band gaps

    Science.gov (United States)

    Kim, Eunho; Yang, Jinkyu

    2014-11-01

    We study the formation of frequency band gaps in single column woodpile phononic crystals composed of orthogonally stacked slender cylinders. We focus on investigating the effect of the cylinders' local vibrations on the dispersion of elastic waves along the stacking direction of the woodpile phononic crystals. We experimentally verify that their frequency band structures depend significantly on the bending resonant behavior of unit cells. We propose a simple theoretical model based on a discrete element method to associate the behavior of locally resonant cylindrical rods with the band gap formation mechanism in woodpile phononic crystals. The findings in this work imply that we can achieve versatile control of frequency band structures in phononic crystals by using woodpile architectures. The woodpile phononic crystals can form a new type of vibration filtering devices that offer an enhanced degree of freedom in manipulating stress wave propagation.

  12. Marine Carotenoids: Biological Functions and Commercial Applications

    OpenAIRE

    Vega, José M.; Inés Garbayo; Francisco Bédmar; María Cuaresma; Carlos Vílchez; Eduardo Forján

    2011-01-01

    Carotenoids are the most common pigments in nature and are synthesised by all photosynthetic organisms and fungi. Carotenoids are considered key molecules for life. Light capture, photosynthesis photoprotection, excess light dissipation and quenching of singlet oxygen are among key biological functions of carotenoids relevant for life on earth. Biological properties of carotenoids allow for wide range of commercial applications. Indeed, recent interest in the carotenoids has be...

  13. Supercoiled DNA; plectonemic structure and liquid crystal formation

    CERN Document Server

    Maarel, J R C; Jesse, W; Backendorf, C; Egelhaaf, S U; Lapp, A

    2003-01-01

    We have investigated the phase behaviour of pUC18 plasmid solutions with phase separation experiments and polarized light microscopy. Furthermore, the configuration of the superhelix is monitored with small-angle neutron scattering. The phase diagram is interpreted with liquid crystal theory including the effects of charge, orientation entropy, excluded volume, as well as the elastic, entropic and electrostatic contributions to the molecular free energy.

  14. Carotenoid photoprotection in Diaptomus kenai

    Energy Technology Data Exchange (ETDEWEB)

    Hairston, N.G. Jr.

    1978-12-01

    Red copepods have been reported from a wide variety of aquatic environments. The red color is produced by a carotenoid pigment, in most cases astaxanthin and its esters, that the copepods cannot form de novo but derive from ingested pigments such as beta-carotene. In an earlier study, the adaptive advantage of carotenoid pigmentation was investigated. Copepods containing large amounts of astaxanthin had significantly better survival than copepods containing small amounts of the pigment when exposed to light of an intensity and color similar to that occurring in the lakes from which they were taken. This result suggested that the carotenoid pigment protected the copepods from photodamage by visible light. Here a second example of carotenoid photoprotection involving the copepod Diaptomus kenai found in fresh-water mountain lakes is described. Information on the vertical distributions of D. sicilis and D. nevadensis in relation to their pigmentation is summarized, as these data will be presented elsewhere.

  15. THE RESULTS OF TESTING TO EVALUATE CRYSTAL FORMATION AND SETTLING IN THE COLD CRUCIBLE INDUCTION MELTER

    Energy Technology Data Exchange (ETDEWEB)

    Marra, J.

    2009-06-30

    The Cold Crucible Induction Melter (CCIM) technology offers the potential to increase waste loading for High Level Waste (HLW) glasses leading to significant improvements in waste throughput rates compared to the reference Joule Heated Melter (JHM). Prior to implementation of a CCIM in a production facility it is necessary to better understand processing constraints associated with the CCIM. The glass liquidus temperature requirement for processing in the CCIM is an open issue. Testing was conducted to evaluate crystal formation and crystal settling during processing in the CCIM to gain insight into the effects on processing. A high aluminum/high iron content glass composition with known crystal formation tendencies was selected for testing. A continuous melter test was conducted for approximately 51 hours. To evaluate crystal formation, glass samples were obtained from pours and from glass receipt canisters where the glass melt had varying residence time in the melter. Additionally, upon conclusion of the testing, glass samples from the bottom of the melter were obtained to assess the degree of crystal settling. Glass samples were characterized in an attempt to determine quantitative fractions of crystals in the glass matrix. Crystal identity and relative composition were determined using a combination of x-ray diffraction (XRD) and scanning electron microscopy coupled with energy dispersive spectroscopy (SEM/EDS). Select samples were also analyzed by digesting the glass and determining the composition using inductively coupled atomic emission spectroscopy (ICP-AES). There was evidence of crystal formation (primarily spinels) in the melt and during cooling of the collected glass. There was evidence of crystal settling in the melt over the duration of the melter campaign.

  16. Nanocrystalline structure formation at crystallization of Fe-Nd films

    International Nuclear Information System (INIS)

    Fe100-xNdx films (x=33,50,75,83) were prepared by vacuum evaporation technique. The TEM data show that initial films contain amorphous phase. Maximal quantity of amorphous phase was found for x=33. The diffraction of amorphous phase differs from ones of as-quenched alloys. The films were treated by electron beam treatment in-situ at multistage regime. The crystallization process was registered step by step. The different behavior at various intensity of treatment was observed. During the first stage of treatment the nanosize precipitations (7-50 nm) are found to form. Relatively stable nanocrystalline structure at x=33 consists of α-Fe precipitations in amorphous matrix. Fine dispersed nanosize structure appears at first stage of crystallization in films with x=75. During electron beam treatment the last structure transforms in local spherical areas. In films at x=83 the bcc-Nd based solid solution and/or fcc γ-phase appear. (orig.)

  17. Monitoring of hydroxyapatite crystal formation using field-effect transistor

    Science.gov (United States)

    Kajisa, Taira; Sakata, Toshiya

    2016-04-01

    The biomineralization process of hydroxyapatite (HAp) in simulated body fluid (SBF) was monitored in realtime using extended-gate FETs whose gate electrode was modified with a variety of alkanethiol self-assembled monolayers (SAMs). It was found that the gate surface potential of the carboxyl- and amino-group-terminated SAM-coated gate FET was increased in SBF as HAp crystals grew on the gate surface. Moreover, in the carboxyl-group-terminated SAM-coated gate FET, the rate of increase and the shift of gate surface potential of the FET were found to depend on the concentration of calcium ions in the SBF. It was concluded that the process of HAp crystallization at a SAM-modified surface can be detected using FETs. Thus, a FET device that enables the easy detection of ionic charges in a real-time and label-free manner, will be useful for evaluating biomaterials based on biomineralization such as those in the bone regeneration process.

  18. Comparison of the mechanism of gap formation for tri- and bi-component phononic crystal

    Institute of Scientific and Technical Information of China (English)

    Zhao Hong-Gang; Wen Ji-Hong; Liu Yao-Zong; Yu Dian-Long; Wang Gang; Wen Xi-Sen

    2008-01-01

    Using an exact Mie scattering solution, this paper investigates the mode conversions during the Mie scattering of a single bi- or one-component sphere in unbounded epoxy. Then the formation mechanism of the first complete gap in the corresponding tri- or bi-component phononic crystal is investigated by the multiple-scattering method. It is shown that the heavy density of the scatterer plays an essential role in the Mie resonance and the formation of the gaps for both types of the phononic crystals. For the tri-component phononic crystal, the gap is mainly induced by the Mie resonance of the single scatterer. For the bi-component phononic crystal, the transverse wave (by mode-conversion during the Mie scattering under a longitudinal wave incidence) is modulated by the periodicity and governed by the Bloch theory,which induces the gap cooperatively.

  19. Crystal Ice Formation of Solution and Its Removal Phenomena From Cooled Solid Surface

    Science.gov (United States)

    Hirata, Tetsuo; Ishikawa, Masaaki; Nagasaka, Kouji

    Experimental studies for freezing phenomena of ethylene glycol solution on cooled plate have been performed. A polyvinyl chloride as well as an acrylic resin plates are used for the cooled plates. It is found that the crystal ice formed at the cooled plate is removed from the plate due to buoyancy force acting the crystal ice. It means that ice formation on a cooled plate without deposit ice layer is possible by the present method. It is shown that the cooled plate surface is under cooled about 1.0~1.5 degree below the freezing temperature of the solution during the crystal ice formation and its removal phenomena. The degree of under cooled temperature is unaffected by the cooling temperature of the plate. For higher concentration of solution, it is found that the number of the removed crystal ice per unit time is increased and the volume of each removed ice is decreased.

  20. Formation and growth mechanism of TiC crystal in TiCp/Ti composites

    Institute of Scientific and Technical Information of China (English)

    金云学; 王宏伟; 曾松岩; 张二林

    2002-01-01

    Ti-C and Ti-Al-C alloys were prepared using gravity and directional solidification processes. Morphologies of TiC crystal were investigated by using SEM, XRD and EDX. Also, the formation and growth mechanism of TiC crystal have been analyzed on the basis of coordination polyhedron growth unit theory. During solidification of titanium alloys, the coordination polyhedron growth unit is TiC6. TiC6 growth units stack in a linking mode of edge to edge and form octahedral TiC crystal with {111} planes as present faces. Although the growing geometry of TiC crystal is decided by its lattice structure, the final morphology of TiC crystal depends on the effects of its growth environment. In solute concentration distribution, the super-saturation of C or TiC6 at the corners of octahedral TiC crystal is much higher than that of edges and faces of octahedral TiC crystal. At these corners the driving force for crystal growth is greater and the interface is instable which contribute to quick stacking rate of growth units at these corners and result in secondary dendrite arms along TiC crystallographic 〈100〉 directions. TiC crystal finally grows to be dendrites.

  1. Adding microchemistry to microstructure: Potential causes for the formation of continuous crystal networks in subliquidus basalt

    Science.gov (United States)

    Sethian, J. A.; Suckale, J.

    2013-12-01

    Much of the compositional variation of igneous rocks results from the separation of liquid from crystals, a process that depends sensitively on the presence of crystal networks. The formation of a continuous crystal network may also lead to finite yield strength and thus cause a change from a Newtonian to a nonlinear rheology with important consequences for flow behavior. While numerous empirical relationships describing yield strength in particle suspensions exist, they provide limited insight into the physics underlying the rheological transition. The goal of this study is to investigate potential causes behind the formation of crystal networks and the associated onset of yield strength. We have developed a computational technique for modeling flow at the scale of individual crystals in both 2D and 3D. In our computations, crystals and magmatic fluid are fully coupled meaning that we are not only resolving the effect of the ambient flow field on the motion of the crystals, but also the hydrodynamic interactions between crystals and their feedback on the magmatic liquid. This type of approach allows us to derive the macroscopic behavior of the aggregate essentially from first principles. We assume that the basaltic liquid has a Newtonian rheology and that the crystals behave as solid bodies. The solid-body motion of the crystals can then be captured through an additional body force in the Stokes equation, which obviates the need for a body-fitted mesh and improves the computational efficiency in 3D. We have extensively benchmarked our code for both spherical and cubical crystal shapes to verify that we are able to reproduce drag forces measured in experiments. Previous studies have demonstrated that crystal shape is an important parameter in determining the crystal fraction over which crystal-bearing magmas exhibit finite yield strengths. The structural characteristics of the crystalline phase, including the shape and aspect ratio of individual crystals as well as

  2. Spectroscopy and Photochemistry in Single Crystals of Uranyl Formate Monohydrate.

    Science.gov (United States)

    Cox, Jack Neal

    1982-03-01

    UO(,2)CH(OO)(,2)(.)H(,2)O, (UFM) is an orthorhombic crystal (Fdd2, C(,2v)('19)) with two uranyls per unit cell. Above 210(DEGREES)K, when uranyl is excited by visible light, a two-step reaction occurs. The primary photochemical step is. U(VI)O(,2)('++) + HCOO('-) (--->) U(V) + (HCOO(.) or CO(,2)('-)). (1). A study of UFM in the oriented solid explores one of the most basic chemical reactions--the redox reaction. High resolution, polarized absorption and excitation specta were taken on single crystals at liquid helium temperatures. Eight electronic origins are identified, each split into doublets by factor group interactions. Uranyl (a)symmetric stretch vibronic progressions (do not) preserve the factor group splittings and polarizations of their origins. The spectrum of UFM lies closer to the (omega)-(omega) limit, as opposed to Russell-Saunders, than Cs(,2)UO(,2)Cl(,4). Low site symmetry depolarizes the B-symmetry components of the origins. Below 2(DEGREES)K, where UFM exhibits non-single exponential luminescence decay, migration to traps is limited. By 20(DEGREES)K, where the curves become single exponential and drop tenfold in the value of the lifetime, emission is occurring from UFM in thermal equilibrium with a population of killer traps. Above 70(DEGREES)K, the lifetime slowly rises. It peaks at 135(DEGREES)K, and then drops steeply, falling below detectability by 210(DEGREES)K. The drop is accompanied by the onset of photoreactivity. The rise in emission is attributed either to a decrease in trapping efficiency or to a hindered migration to traps due to a thermal population of bound (DELTA)(,g) excitons. ESR studies show that a signal at g = 2.0 observed at 77(DEGREES)K is from surface radicals. Below 20(DEGREES)K, a signal near g = 2.1 is due to organic radicals in the bulk generated by the photochemical step. Studies on a single crystal resolve these signals into components that reflect the crystallographic symmetry elements. A signal near g = 3.4 is

  3. Formation of the molecular crystal structure during the vacuum sublimation of paracetamol

    Science.gov (United States)

    Belyaev, A. P.; Rubets, V. P.; Antipov, V. V.; Bordei, N. S.

    2015-04-01

    The results from structural and thermal studies on the formation of molecular crystals during the vacuum sublimation of paracetamol from its vapor phase are given. It is established that the vapor-crystal phase transition proceeds in a complicated way as the superposition of two phase transitions: a first-order phase transition with a change in density, and a second-order phase transition with a change in ordering. It is shown that the latter is a smeared phase transition that proceeds with the formation of a pretransitional phase that is irreversibly dissipated during phase transformation, leading to the formation of crystals of the rhombic syngony. Data from differential scanning calorimetry and X-ray diffraction analysis are presented along with microphotographs.

  4. Dietary Carotenoids Regulate Astaxanthin Content of Copepods and Modulate Their Susceptibility to UV Light and Copper Toxicity

    OpenAIRE

    Carman, Kevin R.; Silva, Soraya J.; Maria-José Caramujo; Carla C. C. R. de Carvalho

    2012-01-01

    High irradiation and the presence of xenobiotics favor the formation of reactive oxygen species in marine environments. Organisms have developed antioxidant defenses, including the accumulation of carotenoids that must be obtained from the diet. Astaxanthin is the main carotenoid in marine crustaceans where, among other functions, it scavenges free radicals thus protecting cell compounds against oxidation. Four diets with different carotenoid composition were used to culture the meiobenthic c...

  5. Pattern formation in crystal growth under parabolic shear flow.

    Science.gov (United States)

    Ueno, K

    2003-08-01

    Morphological instability of the solid-liquid interface occurring in a crystal growing from an undercooled thin liquid bounded on one side by a free surface and flowing down inclined plane, is investigated by a linear stability analysis under shear flow. It is found that restoring forces due to gravity and surface tension is an important factor for stabilization of the solid-liquid interface on long length scales. This is a stabilizing effect different from the Gibbs-Thomson effect. A particular long wavelength mode of about 1 cm of wavy pattern, observed on the surface of icicles covered with a thin layer of flowing water is obtained from the dispersion relation, including the effect of flow and restoring forces. PMID:14524982

  6. Wigner crystal model of counterion induced bundle formation of rod-like polyelectrolytes

    OpenAIRE

    Shklovskii, B. I.

    1998-01-01

    A simple electrostatic theory of condensation of rod-like polyelectrolytes under influence of polyvalent ions is proposed. It is based on the idea that Manning condensation of ions results in formation of the Wigner crystal on a background of a bundle of rods. It is shown that, depending on a single dimensionless parameter, this can be the densely packed three-dimensional Wigner crystal or the two-dimensional crystal on the rod surfaces. For DNA the location of charge on the spiral results in...

  7. Mechanisms of color centor formation in chromium-containing scandium garnet crystals

    International Nuclear Information System (INIS)

    Mekhanisms of absorption induced by UV pumping radiation in chromium-containing crystals of scandium garnets (GSGG:Cr3+; GSGG:Cr3+, Nd3+; ISGG:Cr3+) are revealed. It is experimentally ascertained that color center formation processes in two-activated crystals are sufficiently suppressed. This is conditioned by a reduction of contribution to the process of coloring of charges released by shortwave pumping radiation from Cr3+ ion metastable level, the population of which in a two-activated crystal is low due to efficient Cr3+→Nd3+ energy transfer

  8. Unsaturated glycerophospholipids mediate heme crystallization: biological implications for hemozoin formation in the kissing bug Rhodnius prolixus.

    Directory of Open Access Journals (Sweden)

    Renata Stiebler

    Full Text Available Hemozoin (Hz is a heme crystal produced by some blood-feeding organisms, as an efficient way to detoxify heme derived from hemoglobin digestion. In the triatomine insect Rhodnius prolixus, Hz is essentially produced by midgut extracellular phospholipid membranes known as perimicrovillar membranes (PMVM. Here, we investigated the role of commercial glycerophospholipids containing serine, choline and ethanolamine as headgroups and R. prolixus midgut lipids (RML in heme crystallization. All commercial unsaturated forms of phospholipids, as well as RML, mediated fast and efficient β-hematin formation by means of two kinetically distinct mechanisms: an early and fast component, followed by a late and slow one. The fastest reactions observed were induced by unsaturated forms of phosphatidylethanolamine (uPE and phosphatidylcholine (uPC, with half-lives of 0.04 and 0.7 minutes, respectively. β-hematin crystal morphologies were strikingly distinct among groups, with uPE producing homogeneous regular brick-shaped crystals. Interestingly, uPC-mediated reactions resulted in two morphologically distinct crystal populations: one less representative group of regular crystals, resembling those induced by uPE, and the other largely represented by crystals with numerous sharp edges and tapered ends. Heme crystallization reactions induced by RML were efficient, with a heme to β-hematin conversion rate higher than 70%, but clearly slower (t1/2 of 9.9-17.7 minutes than those induced by uPC and uPE. Interestingly, crystals produced by RML were homogeneous in shape and quite similar to those mediated by uPE. Thus, β-hematin formation can be rapidly and efficiently induced by unsaturated glycerophospholipids, particularly uPE and uPC, and may play a role on biological heme crystallization in R. prolixus midgut.

  9. Formation mechanism of CaTiO3 hollow crystals with different microstructures.

    Science.gov (United States)

    Yang, Xianfeng; Fu, Junxiang; Jin, Chongjun; Chen, Jian; Liang, Chaolun; Wu, Mingmei; Zhou, Wuzong

    2010-10-13

    The crystal growth of CaTiO(3) hollow crystals with different microstructures has been investigated. In a water-free poly(ethylene glycol) 200 (PEG-200) solution, CaTiO(3) nanocubes formed first. The nanocubes underwent an oriented self-assembly into spherical particles, enhanced by the surface-adsorbed polymer molecules. Since the growth of nanocubes and their aggregation took place simultaneously, the nanocubes in the outer shells were larger than those in the cores. Disappearance of the small nanocubes in the cores of the spheres during an Ostwald ripening process led to spherical hollow crystals. Addition of a small amount of water (1.25 vol %) in the polymer solution enhanced surface recrystallization of the aggregated spheres, forming a cubic morphology. The orthorhombic distortion of the perovskite CaTiO(3) structure did not have a significant effect on the nanocube aggregation, resulting in a domain structure in the shells. Single-crystalline hollow cubes were produced with a slightly higher water content, e.g., 5 vol %. This process of (1) aggregation of nanocubes and (2) surface crystallization followed by (3) surface-to-core extension of recrystallization gives a good example of the reversed crystal growth route in ceramic materials. The proposed formation mechanism of the hollow CaTiO(3) crystals would enable us to control the microstructures of these materials and to explain the formation of many other hollow crystals. PMID:20843080

  10. Carotenoid dynamics in Atlantic salmon

    Directory of Open Access Journals (Sweden)

    Omholt Stig W

    2006-04-01

    Full Text Available Abstract Background Carotenoids are pigment molecules produced mainly in plants and heavily exploited by a wide range of organisms higher up in the food-chain. The fundamental processes regulating how carotenoids are absorbed and metabolized in vertebrates are still not fully understood. We try to further this understanding here by presenting a dynamic ODE (ordinary differential equation model to describe and analyse the uptake, deposition, and utilization of a carotenoid at the whole-organism level. The model focuses on the pigment astaxanthin in Atlantic salmon because of the commercial importance of understanding carotenoid dynamics in this species, and because deposition of carotenoids in the flesh is likely to play an important life history role in anadromous salmonids. Results The model is capable of mimicking feed experiments analyzing astaxanthin uptake and retention over short and long time periods (hours, days and years under various conditions. A sensitivity analysis of the model provides information on where to look for possible genetic determinants underlying the observed phenotypic variation in muscle carotenoid retention. Finally, the model framework is used to predict that a specific regulatory system controlling the release of astaxanthin from the muscle is not likely to exist, and that the release of the pigment into the blood is instead caused by the androgen-initiated autolytic degradation of the muscle in the sexually mature salmon. Conclusion The results show that a dynamic model describing a complex trait can be instrumental in the early stages of a project trying to uncover underlying determinants. The model provides a heuristic basis for an experimental research programme, as well as defining a scaffold for modelling carotenoid dynamics in mammalian systems.

  11. Carotenoid profile and retention in yellow-, purple- and red-fleshed potatoes after thermal processing.

    Science.gov (United States)

    Kotíková, Zora; Šulc, Miloslav; Lachman, Jaromír; Pivec, Vladimír; Orsák, Matyáš; Hamouz, Karel

    2016-04-15

    This research aimed to investigate the effect of thermal processing on carotenoid profile, quantity and stability in 22 colour-fleshed potato cultivars grown in the Czech Republic. The total of nine carotenoids was analysed by HPLC using a C30 column and PDA detection. The total carotenoid content for all cultivars ranged from 1.44 to 40.13 μg/g DM. Yellow cultivars showed a much higher average total carotenoid content (26.22 μg/g DM) when compared to red/purple-fleshed potatoes (5.69 μg/g DM). Yellow cultivars were dominated by antheraxanthin, whereas neoxanthin was the main carotenoid in red/purple cultivars. Thermal processing significantly impacted all potato cultivars. Boiling decreased the total carotenoids by 92% compared to baking (88%). Lutein was the most stable carotenoid against thermal processing (decreased by 24-43%) followed by β-carotene (decreased by 78-83%); other carotenoids were degraded nearly completely. Increased formation of (Z)-isomers by thermal processing has not been confirmed. PMID:26617045

  12. The Or Gene Enhances Carotenoid Accumulation and Stability During Post-Harvest Storage of Potato Tubers

    Institute of Scientific and Technical Information of China (English)

    Li Li; Mark Failla; Theodore W.Thannhauser; Yong Yang; Qiang Xu; Katherine Owsiany; Ralf Welsch; Chureeporn Chitchumroonchokchai; Shan Lu; Joyce Van Eck; Xiu-Xin Deng

    2012-01-01

    Provitamin A carotenoids in staple crops are not very stable during storage and their loss compromises nutritional quality.To elucidate the fundamental mechanisms underlying carotenoid accumulation and stability,we investigated transgenic potato tubers that expressed the cauliflower Orange (Or) gene.We found that the Or transgene not only promoted retention of β-carotene level,but also continuously stimulated its accumulation during 5 months of cold storage.In contrast,no increased levels of carotenoids were observed in the tubers of vector-only controls or a yellowflesh variety during the same period of storage.The increased carotenoid accumulation was found to be associated with the formation of lipoprotein-carotenoid sequestering structures,as well as with the enhanced abundance of phytoene synthase,a key enzyme in the carotenoid biosynthetic pathway.Furthermore,the provitamin A carotenoids stored were shown to be stable during simulated digestion and accessible for uptake by human intestinal absorptive cells.Proteomic analysis identified three major functional groups of proteins (i.e.heat shock proteins,glutathione-S-transferases,and carbohydrate metabolic proteins) that are potentially important in the Or-regulated carotenoid accumulation.Our results show that regulation of carotenoid sequestration capacity is an important mechanism by which carotenoid stability is regulated.Our findings suggest that induction of a proper sink structure formation in staple crops may provide the crops with a unique ability to promote and/or stabilize provitamin A accumulation during plant growth and post-harvest storage.

  13. Matrix Gla Protein is Involved in Crystal Formation in Kidney of Hyperoxaluric Rats

    Directory of Open Access Journals (Sweden)

    Xiuli Lu

    2013-02-01

    Full Text Available Background: Matrix Gla protein (MGP is a molecular determinant regulating vascular calcification of the extracellular matrix. However, it is still unclear how MGP may be invovled in crystal formation in the kidney of hyperoxaluric rats. Methods: Male Sprague-Dawley rats were divided into the hyperoxaluric group and control group. Hyperoxaluric rats were administrated by 0.75% ethylene glycol (EG for up to 8 weeks. Renal MGP expression was detected by the standard avidin-biotin complex (ABC method. Renal crystal deposition was observed by a polarizing microscope. Total RNA and protein from the rat kidney tissue were extracted. The levels of MGP mRNA and protein expression were analyzed by the real-time polymerase chain reaction (RT-PCR and Western blot. Results: Hyperoxaluria was induced successfully in rats. The MGP was polarly distributed, on the apical membrane of renal tubular epithelial cells, and was found in the ascending thick limbs of Henle's loop (cTAL and the distal convoluted tubule (DCT in hyperoxaluric rats, its expression however, was present in the medullary collecting duct (MCD in stone-forming rats. Crystals with multilaminated structure formed in the injurious renal tubules with lack of MGP expression.MGP mRNA expression was significantly upregulated by the crystals' stimulations. Conclusion: Our results suggested that the MGP was involved in crystals formation by the continuous expression, distributing it polarly in the renal tubular cells and binding directly to the crystals.

  14. Refractive Index Change and Color Center Formation in LiYF_4 Crystal Induced by a Femtosecond Laser

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    The refractive index change and color centers formation in LiYF4 crystal at room temperature are induced by a femtosecond laser irradiation. A mechanism for refractive index change and color centers formation is proposed.

  15. The Formation of Crystal Defects in a Fe-Mn-Si Alloy Under Cyclic Martensitic Transformations.

    Science.gov (United States)

    Bondar, Vladimir I; Danilchenko, Vitaliy E; Iakovlev, Viktor E

    2016-12-01

    Formation of crystalline defects due to cyclic martensitic transformations (CMT) in the iron-manganese Fe-18 wt.% Mn-2 wt.% Si alloy was investigated using X-ray diffractometry. Conditions for accumulation of fragment sub-boundaries with low-angle misorientations and chaotic stacking faults in crystal lattice of austenite and ε-martensite were analyzed. PMID:26960743

  16. Formation of nano-hydroxyapatite crystal in situ in chitosan-pectin polyelectrolyte complex network

    International Nuclear Information System (INIS)

    Hydroxyapatite (HA)/polysaccharide composites have been widely used in bone tissue engineering due to their chemical similarity to natural bone. Polymer matrix-mediated synthesis of nano-hydroxyapatite is one of the simplest models for biomimetic. In this article, the nano-hydroxyapatite/chitosan-pectin (nHCP) composites were prepared through in situ mineralization of hydroxyapatite in chitosan-pectin polyelectrolyte complex (PEC) network. The formation processes of nHCP were investigated by X-ray diffraction (XRD) analysis. The interactions between nHA crystal and chitosan-pectin PEC networks were studied using Fourier Transform Infrared Spectroscopy (FTIR) and Differential Scanning Calorimetry (DSC). The morphology and structure of nHA crystal were characterized by XRD and Transmission Electron Microscope (TEM). Results suggested that the interfacial interactions between nano-hydroxyapatite crystal and chitosan-pectin PEC network assist the site specific nucleation and growth of nHA nanoparticles. The nHA crystals grow along the c-axis. In this process, pH value is the main factor to control the nucleation and growth of nHA crystal in chitosan-pectin PEC networks, because both the interactions' strength between nHA crystal and chitosan-pectin and diffusion rate of inorganic ions depend on the pH value of the reaction system. Apart from the pH value, the chitosan/pectin ratio and [Ca2+] also take important effects on the formation of nHA crystal. An effective way to control the size of nHA crystal is to adjust the content of pectin and [Ca2+]. It is interesting that the Zeta potential of nHCP composites is about - 30 mV when the chitosan/pectin ratio ≤ 1:1, and the dispersion solution of nHCP composites has higher stability, which provides the possibility to prepare 3D porous scaffolds with nHCP for bone tissue engineering.

  17. Crystal structures of complexes of NAD+-dependent formate dehydrogenase from methylotrophic bacterium Pseudomonas sp. 101 with formate

    International Nuclear Information System (INIS)

    Formate dehydrogenase (FDH) from the methylotrophic bacterium Pseudomonas sp. 101 catalyzes oxidation of formate to NI2 with the coupled reduction of nicotinamide adenine dinucleotide (NAD+). The three-dimensional structures of the apo form (the free enzyme) and the holo form (the ternary FDH-NAD+-azide complex) of FDH have been established earlier. In the present study, the structures of FDH complexes with formate are solved at 2.19 and 2.28 A resolution by the molecular replacement method and refined to the R factors of 22.3 and 20.5%, respectively. Both crystal structures contain four protein molecules per asymmetric unit. These molecules form two dimers identical to the dimer of the apo form of FDH. Two possible formatebinding sites are found in the active site of the FDH structure. In the complexes the sulfur atom of residue Cys354 exists in the oxidized state

  18. Disorderly crystal structures in transition metal rich-metalloid alloys: implications for glass formation

    International Nuclear Information System (INIS)

    Easy glass formation usually occurs near eutectics where the glass forming temperature is close to the melting point. However, as Anderson observed [1], other factors also enter. Citing covalent systems such as SiO2 and GeS2, he noted that glass formation is favored when the crystal structure(s) of the compounds are complicated. The purpose of the present communication is to see what transition metal rich-metalloid compounds have complicated structures and what implications this might have for glass formation

  19. Ion-induced pattern formation on indium tin oxide for alignment of liquid crystals

    International Nuclear Information System (INIS)

    Indium tin oxide (ITO) is broadly used as a transparent conducting material for electrodes in optoelectronic devices. Irradiation of ITO with low energy ions can result in the formation of periodic surface nanopatterns which can serve as an alternative for the polymer alignment layer in liquid crystal devices. We investigated the formation of the ion-induced surface nanopatterns on ITO with focus on the influence of the crystalline structure of the material. We find that the crystallinity plays a crucial role in the pattern formation, with no pattern developing on an amorphous ITO surface. We discuss these findings in the context of the state-of-the-art theory for ion-induced patterning. We show that the ion-induced pattern plays a critical role in the liquid crystal alignment on ITO surfaces

  20. Ion-induced pattern formation on indium tin oxide for alignment of liquid crystals

    Energy Technology Data Exchange (ETDEWEB)

    Škereň, T., E-mail: tomas.skeren@fjfi.cvut.cz [Instituut voor Kern-en Stralingsfysica, KU Leuven, Celestijnenlaan 200D, B-3001 Leuven Belgium (Belgium); Czech Technical University in Prague, Faculty of Nuclear Sciences and Physical Engineering, Břehová 7, 115 19 Prague 1 (Czech Republic); Doornaert, D. [Laboratory for Acoustics and Thermal Physics, Department of Physics and Astronomy, KU Leuven, B-3001 Heverlee (Belgium); Wave Propagation and Signal Processing Research Group, KU Leuven Campus Kortrijk, E. Sabbelaan 53, B-8500 Kortrijk (Belgium); Glorieux, C. [Laboratory for Acoustics and Thermal Physics, Department of Physics and Astronomy, KU Leuven, B-3001 Heverlee (Belgium); Modarresi, H. [Instituut voor Kern-en Stralingsfysica, KU Leuven, Celestijnenlaan 200D, B-3001 Leuven Belgium (Belgium); Guan, T. [Departement Elektrotechniek ESAT-MICAS, KU Leuven, Kasteelpark Arenberg 10, B-3001 Leuven (Belgium); Temst, K. [Instituut voor Kern-en Stralingsfysica, KU Leuven, Celestijnenlaan 200D, B-3001 Leuven Belgium (Belgium); Vandervorst, W. [Instituut voor Kern-en Stralingsfysica, KU Leuven, Celestijnenlaan 200D, B-3001 Leuven Belgium (Belgium); IMEC, Kapeldreef 75, B-3001 Leuven (Belgium); Vantomme, A. [Instituut voor Kern-en Stralingsfysica, KU Leuven, Celestijnenlaan 200D, B-3001 Leuven Belgium (Belgium)

    2015-08-31

    Indium tin oxide (ITO) is broadly used as a transparent conducting material for electrodes in optoelectronic devices. Irradiation of ITO with low energy ions can result in the formation of periodic surface nanopatterns which can serve as an alternative for the polymer alignment layer in liquid crystal devices. We investigated the formation of the ion-induced surface nanopatterns on ITO with focus on the influence of the crystalline structure of the material. We find that the crystallinity plays a crucial role in the pattern formation, with no pattern developing on an amorphous ITO surface. We discuss these findings in the context of the state-of-the-art theory for ion-induced patterning. We show that the ion-induced pattern plays a critical role in the liquid crystal alignment on ITO surfaces.

  1. Formation of oriented nitrides by N+ ion implantation in iron single crystals

    International Nuclear Information System (INIS)

    Iron single crystals were implanted with nitrogen at room temperature, with a fluence of 5×1017 cm−2 and 50 keV energy, to produce iron nitride phases and characterize the influence of the crystal orientation. The stability and evolution of the nitride phases and diffusion of implanted nitrogen were studied as a function of successive annealing treatments at 250 °C in vacuum. The composition, structure and magnetic properties were characterized using RBS/channeling, X-Ray Diffraction, Magnetic Force Microscopy, Magneto-optical Kerr Effect and Conversion Electron Mössbauer Spectroscopy. In the as-implanted state the formation of Fe2N phase was clearly identified in all single crystals. This phase is not stable at 250 °C and annealing at this temperature promotes the formation of ε-Fe3N, or γ′-Fe4N, depending on the orientation of the substrate. - Highlights: • Oriented magnetic iron nitrides were obtained by nitrogen implantation into iron single crystals. • The stable magnetic nitride phase at 250 °C depends on the orientation of the host single crystal, being γ'-Fe4N or ε-Fe3N. • The easy magnetization axis was found to lay in the (100) plane for cubic γ'-Fe4N and out of (100) plane for hexagonal ε-Fe3N

  2. Crystal nucleus formation on the cathode under conditions of supersaturation of melt by lower valent forms

    International Nuclear Information System (INIS)

    Nucleation on the cathode of sodium-tungsten bronzes forom the Na2WO4-WO3 melt, containing 40 mol.% WO3 is studied. It has been found that in the initial period the cathode deposition of sodium-tungsten bronze is preceeded by the formation of tungsten soluble lower reduced forms, the concentration of which can considerably exceed the equilibrium one because of excessive overstress of oxide bronze crystal nucleation. The polarization of cathode and change of its potential at the crystal nucleation of sodium-tungsten bronze and switching-off of the electrolysis current has been studied

  3. Self-Organized Collective Crystal-Like Formations of the Attractive/repulsive Swarming System

    Science.gov (United States)

    Tian, Wen-Qiang; Gao, Dan; Wang, Ying-Guan

    2014-01-01

    In this paper, an adaptive attractive/repulsive (A/R) swarming model is proposed to explore the role of self-organized formation in swarming systems. By defining the adjustable A/R range γi, which is affected by the localized steady state of agents, the standard collective crystal-like swarming formations are straightforwardly unfolded in different scale. Meanwhile, with numerical simulations and analyses, the results show that the adaptive A/R swarming model provides an effective solution to the current existing dilemma of the collective liquid-like formation with unexpected neighbor distances and the split crystal-like formation. The actual neighbor distance of the adaptive A/R model could converge to the expected neighbor distance as planned, based on the different settings of the expected neighbor distance and the A/R range. Moreover, such adjustable A/R swarming formations may find their potential applications such as the formation of self-organized multi-robots and unmanned aerial vehicles, the automatic networking of sensors, etc.

  4. Self-organization processes and nanocluster formation in crystal lattices by low-energy ion irradiation

    International Nuclear Information System (INIS)

    The goal of this paper is to study self-organization processes that cause nanostructural evolution in nonlinear crystal media. The subjects of the investigation were nonlinear homogeneous and heterogeneous atom chains. The method of computer simulation was used to investigate the interaction between low-energy ions and crystal lattices. It was based on the conception of three-dimensional lattice as a nonlinear atom chain system. We showed that that in homogeneous atom chains critical energy needed for self-organization processes development is less than for nonlinear atom chain with already embedded clusters. The possibility of nanostructure formation was studied by a molecular dynamics method of nonlinear oscillations in atomic oscillator systems of crystal lattices after their low-energy ion irradiation. (authors)

  5. Excited State Structural Dynamics of Carotenoids and Charge Transfer Systems

    International Nuclear Information System (INIS)

    This dissertation describes the development and implementation of a visible/near infrared pump/mid-infrared probe apparatus. Chapter 1 describes the background and motivation of investigating optically induced structural dynamics, paying specific attention to solvation and the excitation selection rules of highly symmetric molecules such as carotenoids. Chapter 2 describes the development and construction of the experimental apparatus used throughout the remainder of this dissertation. Chapter 3 will discuss the investigation of DCM, a laser dye with a fluorescence signal resulting from a charge transfer state. By studying the dynamics of DCM and of its methyl deuterated isotopomer (an otherwise identical molecule), we are able to investigate the origins of the charge transfer state and provide evidence that it is of the controversial twisted intramolecular (TICT) type. Chapter 4 introduces the use of two-photon excitation to the S1 state, combined with one-photon excitation to the S2 state of the carotenoid beta-apo-8'-carotenal. These 2 investigations show evidence for the formation of solitons, previously unobserved in molecular systems and found only in conducting polymers Chapter 5 presents an investigation of the excited state dynamics of peridinin, the carotenoid responsible for the light harvesting of dinoflagellates. This investigation allows for a more detailed understanding of the importance of structural dynamics of carotenoids in light harvesting

  6. Statistical optimisation of cell growth and carotenoid production by Rhodotorula mucilaginosa

    Directory of Open Access Journals (Sweden)

    Iriani R. Maldonade

    2012-03-01

    Full Text Available Sequential statistical methods were used to maximise carotenoid production by a strain of Rhodotorula mucilaginosa, isolated from the Brazilian ecosystem. Initially, a factorial 2(5-1 experimental design was used, and the variables were pH and the levels of glucose, yeast extract, MgSO4.7H2O and KH2PO4. The nitrogen source (yeast extract was the most important variable in enhancing carotenoid production; MgSO4.7H2O and KH2PO4 had a negative influence. The initial pH had no significant effect on carotenoid and cell productions. We further investigated the effects of glucose and yeast extract effects, using a second-order central composite design (CCD to optimise carotenoid production, which was adequately approximated with a full quadratic equation obtained from a two-factor-2-level design. The analysis of quadratic surfaces showed that after 5 days of cultivation at 25ºC, the maximum carotenoid concentration (745 µg l-1 was obtained with 15 g l-1 of yeast extract and 20 g l-1 of glucose. The maximum carotenoid production (152 µg g-1 was obtained with 5 g l-1 yeast extract and 10 g l-1 glucose. Carotenoid formation was more sensitive to changes in yeast extract concentration than to changes in glucose concentration. Maximum cell production was achieved with 15-17 g l-1 of yeast extract and 15-20 g l-1 of glucose.

  7. Direct observation of two-step crystallization in nanoparticle superlattice formation

    Energy Technology Data Exchange (ETDEWEB)

    Park, Jungwon; Zheng, Haimei; Lee, Won Chul; Geissler, Phillip L.; Rabani, Eran; Alivisatos, A. Paul

    2011-10-06

    Direct imaging of nanoparticle solutions by liquid phase transmission electron microscopy has enabled unique in-situ studies of nanoparticle motion and growth. In the present work, we report on real-time formation of two-dimensional nanoparticle arrays in the very low diffusive limit, where nanoparticles are mainly driven by capillary forces and solvent fluctuations. We find that superlattice formation appears to be segregated into multiple regimes. Initially, the solvent front drags the nanoparticles, condensing them into an amorphous agglomerate. Subsequently, the nanoparticle crystallization into an array is driven by local fluctuations. Following the crystallization event, superlattice growth can also occur via the addition of individual nanoparticles drawn from outlying regions by different solvent fronts. The dragging mechanism is consistent with simulations based on a coarse-grained lattice gas model at the same limit.

  8. Nanostructured diffusion-limited-aggregation crystal pattern formation in a reactive microemulsion system

    International Nuclear Information System (INIS)

    Nanostructured diffusion-limited-aggregation (DLA) crystal pattern formation in microemulsion consisting of water, styrene, cetyltrimethylammonium chloride (CTACl), potassium persulphate and an oscillating Belousov–Zhabotinsky (BZ) reactant is reported. A variety of spatiotemporal patterns like concentric wave, spatial (stripe) and chaotic patterns appear. A colloidal phase composed of numerous nano-sized particles has been observed. The solid phase nucleation has been found to occur in the colloidal phase and has been found to grow in a symmetric crystal pattern with the progress of the reaction finally exhibiting DLA structures. We show that the formation of a nanostructured DLA crystal pattern is governed by spatial structures emerging in the BZ microemulsion system. Without any spatial structure in the microemulsion system only hydrogel of high viscosity is formed. A nano-sized branched crystal pattern was formed with a particle diameter in the range of 60–100 nm, as evident by transmission electron microscope, powder x-ray diffraction and particle size analyser studies. (paper)

  9. Crystal growth limitation as a critical factor for formation of Fe-based bulk metallic glasses

    International Nuclear Information System (INIS)

    In the present work we study the formation mechanism and crystallization behavior of Fe-based bulk metallic glasses influenced by the addition of rare-earth elements. Samples are characterized by conventional X-ray diffractometry, optical microscopy, and high-resolution field-emission-gun scanning and transmission electron microscopy. In the rare-earth-containing alloys, bulk metallic glasses are formed with populations of quenched-in nuclei. Consequently, crystallization on isothermal annealing occurs without any incubation period. This behavior, not typical of bulk metallic glasses in general, implies that in the rare-earth-containing alloys glass formation is possible only because of restricted crystal growth: both on cooling from the molten and on heating from the glassy state, growth of the primary χ-Fe36Cr12Mo10 crystals is too slow to be significant on a reasonable timescale. The low growth rate is connected with large inhomogeneous strain in the growing nanoparticles, while nucleation of eutectic colonies is hampered by slow diffusion of a rare-earth alloying element

  10. Carotenoids in Adipose Tissue Biology and Obesity.

    Science.gov (United States)

    Bonet, M Luisa; Canas, Jose A; Ribot, Joan; Palou, Andreu

    2016-01-01

    Cell, animal and human studies dealing with carotenoids and carotenoid derivatives as nutritional regulators of adipose tissue biology with implications for the etiology and management of obesity and obesity-related metabolic diseases are reviewed. Most studied carotenoids in this context are β-carotene, cryptoxanthin, astaxanthin and fucoxanthin, together with β-carotene-derived retinoids and some other apocarotenoids. Studies indicate an impact of these compounds on essential aspects of adipose tissue biology including the control of adipocyte differentiation (adipogenesis), adipocyte metabolism, oxidative stress and the production of adipose tissue-derived regulatory signals and inflammatory mediators. Specific carotenoids and carotenoid derivatives restrain adipogenesis and adipocyte hypertrophy while enhancing fat oxidation and energy dissipation in brown and white adipocytes, and counteract obesity in animal models. Intake, blood levels and adipocyte content of carotenoids are reduced in human obesity. Specifically designed human intervention studies in the field, though still sparse, indicate a beneficial effect of carotenoid supplementation in the accrual of abdominal adiposity. In summary, studies support a role of specific carotenoids and carotenoid derivatives in the prevention of excess adiposity, and suggest that carotenoid requirements may be dependent on body composition. PMID:27485231

  11. Formation of classical crystals of dipolar particles in a helical geometry

    DEFF Research Database (Denmark)

    K. Pedersen, J.; V. Fedorov, D.; S. Jensen, A.;

    2014-01-01

    We consider crystal formation of particles with dipole-dipole interactions that are confined to move in a one-dimensional helical geometry with their dipole moments oriented along the symmetry axis of the confining helix. The stable classical lowest energy configurations are found to be chain......-to-tail attraction in the system. The speed of sound propagates along the chains. It is independent of the number of chains although depending on geometry....

  12. Defect formation in spinel crystals under electron and gamma beam irradiation

    International Nuclear Information System (INIS)

    There were investigated the optical absorption centers formation in magnesium aluminate spinel crystals at the action of high energy gamma or electron beams. It was revealed that at gamma irradiation the most probably the hole centers are formed to compare with that in electron irradiation. At electron beam irradiation the temperature of sample was raised which leads to thermal annealing of unstable radiation-induced centers

  13. Enthalpies of crystal lattices and standard enthalpies of formation of crystalline metal haloacetates

    Science.gov (United States)

    Baluev, A. V.

    1999-01-01

    A method for the calculation of the enthalpies of crystal lattices and standard enthalpies of formation of anhydrous metal nitrates is presented. The estimation of ÄHlat is based on interpolation of the linear plots of this value vs. the Edwards parameter, which, in turn, is a linear function of the logarithm of the acid dissociation constant. Linearity of the above dependence was previously found experimentally for the corresponding uranyl salts. Previously unknown lattice enthalpies and standard enthalpies of formation of a large set of anhydrous metal nitrates and carboxylates are calculated.

  14. Relationship between Multi-Phase Formation and Molecular Structure for Liquid Crystal System

    Institute of Scientific and Technical Information of China (English)

    LI Zhenxin; MA Heng; LI Shipu

    2005-01-01

    A mechanical model of liquid crystals ( LCs ) was used to explain the phase formation and thermal properties. The LC phases in the model are micro-machine systems consisting of an ensemble of molecular rotors, and some dynamic parameters in a semi-experiment molecular orbit method. A novel explanation on the multi-phase formation of LC system is obtained. It is found that the value of the critical rotational velocity is a key parameter for the characterization of each homologous series. The dipole moment of the molecules was also discussed.

  15. Formation of Nanotwin Networks during High-Temperature Crystallization of Amorphous Germanium

    Science.gov (United States)

    Sandoval, Luis; Reina, Celia; Marian, Jaime

    2015-11-01

    Germanium is an extremely important material used for numerous functional applications in many fields of nanotechnology. In this paper, we study the crystallization of amorphous Ge using atomistic simulations of critical nano-metric nuclei at high temperatures. We find that crystallization occurs by the recurrent transfer of atoms via a diffusive process from the amorphous phase into suitably-oriented crystalline layers. We accompany our simulations with a comprehensive thermodynamic and kinetic analysis of the growth process, which explains the energy balance and the interfacial growth velocities governing grain growth. For the crystallographic orientation, we find a degenerate atomic rearrangement process, with two zero-energy modes corresponding to a perfect crystalline structure and the formation of a Σ3 twin boundary. Continued growth in this direction results in the development a twin network, in contrast with all other growth orientations, where the crystal grows defect-free. This particular mechanism of crystallization from amorphous phases is also observed during solid-phase epitaxial growth of semiconductor crystals, where growth is restrained to one dimension. We calculate the equivalent X-ray diffraction pattern of the obtained nanotwin networks, providing grounds for experimental validation.

  16. Do carboximide–carboxylic acid combinations form co-crystals? The role of hydroxyl substitution on the formation of co-crystals and eutectics

    Directory of Open Access Journals (Sweden)

    Ramanpreet Kaur

    2015-05-01

    Full Text Available Carboxylic acids, amides and imides are key organic systems which provide understanding of molecular recognition and binding phenomena important in biological and pharmaceutical settings. In this context, studies of their mutual interactions and compatibility through co-crystallization may pave the way for greater understanding and new applications of their combinations. Extensive co-crystallization studies are available for carboxylic acid/amide combinations, but only a few examples of carboxylic acid/imide co-crystals are currently observed in the literature. The non-formation of co-crystals for carboxylic acid/imide combinations has previously been rationalized, based on steric and computed stability factors. In the light of the growing awareness of eutectic mixtures as an alternative outcome in co-crystallization experiments, the nature of various benzoic acid/cyclic imide combinations is established in this paper. Since an additional functional group can provide sites for new intermolecular interactions and, potentially, promote supramolecular growth into a co-crystal, benzoic acids decorated with one or more hydroxyl groups have been systematically screened for co-crystallization with one unsaturated and two saturated cyclic imides. The facile formation of an abundant number of hydroxybenzoic acid/cyclic carboximide co-crystals is reported, including polymorphic and variable stoichiometry co-crystals. In the cases where co-crystals did not form, the combinations are shown invariably to result in eutectics. The presence or absence and geometric disposition of hydroxyl functionality on benzoic acid is thus found to drive the formation of co-crystals or eutectics for the studied carboxylic acid/imide combinations.

  17. Microalgae as Sources of Carotenoids

    Directory of Open Access Journals (Sweden)

    Francisco Xavier Malcata

    2011-04-01

    Full Text Available Marine microalgae constitute a natural source of a variety of drugs for pharmaceutical, food and cosmetic applications—which encompass carotenoids, among others. A growing body of experimental evidence has confirmed that these compounds can play important roles in prevention (and even treatment of human diseases and health conditions, e.g., cancer, cardiovascular problems, atherosclerosis, rheumatoid arthritis, muscular dystrophy, cataracts and some neurological disorders. The underlying features that may account for such favorable biological activities are their intrinsic antioxidant, anti-inflammatory and antitumoral features. In this invited review, the most important issues regarding synthesis of carotenoids by microalgae are described and discussed—from both physiological and processing points of view. Current gaps of knowledge, as well as technological opportunities in the near future relating to this growing field of interest, are also put forward in a critical manner.

  18. Carotenoid changes of intact watermelons after storage.

    Science.gov (United States)

    Perkins-Veazie, Penelope; Collins, Julie K

    2006-08-01

    Watermelon contains lycopene, a red carotenoid pigment that has strong antioxidant properties. The lycopene content of watermelon is substantial, contributing 8-20 mg per 180 g serving. There are no reports on carotenoid changes in whole watermelon during storage. Three types of watermelon, open-pollinated seeded, hybrid seeded, and seedless types, were stored at 5, 13, and 21 degrees C for 14 days and flesh color, composition, and carotenoid content were compared to those of fruit not stored. Watermelons stored at 21 degrees C had increased pH, chroma, and carotenoid content compared to fresh fruit. Compared to fresh fruit, watermelons stored at 21 degrees C gained 11-40% in lycopene and 50-139% in beta-carotene, whereas fruit held at 13 degrees C changed little in carotenoid content. These results indicate that carotenoid biosynthesis in watermelons can be affected by temperature and storage. PMID:16881688

  19. Carotenoids content and sunlight susceptibility

    International Nuclear Information System (INIS)

    Full text: An environmental pink pigmented bacterium was isolated and identified as Rhodococcus sp. Pigmentation mutants were obtained by chemical mutagenesis. Pigments present in the wild type strain (RMB90), in a pale yellow mutant (RMB91) and in two mutants exhibiting increased pigmentation (RMB92 and RMB93), were extracted with chloroform-methanol and analyzed by reverse phase HPLC. Survival of these strains after exposure to sunlight and ultraviolet radiation from artificial sources was studied under different physiological and irradiation conditions. The ability of RMB91 to survive sunlight exposure was reduced with respect to that of RMB90. Resistance was similar in both strains when bacteria grew in the presence of a carotenoid synthesis inhibitor, which had no effect on survival of RMB91. Reduced sunlight resistance in RMB91 was also observed during irradiations under N2. Using artificial radiation sources, non pigmented bacteria were less resistant to UVA, but not to UVB or UVC. Lethal effects of sunlight and UVA on RMB92 and RMB93 were increased with respect to the wild type strain. Carotenoids protect Rhodococcus sp against deleterious effects of sunlight. In non-photosynthetic bacteria studied to date, photo protection by carotenoids was dependent on [O2]. This is not the case with Rhodococcus sp RMB90, suggesting the occurrence of a different mechanism for protection. UVA radiation seems to playa key role in photo-damage. (author)

  20. Allometric deviations of plasma carotenoids in raptors

    OpenAIRE

    Blanco, Guillermo; Bautista, Luis M.; Hornero-Méndez, Dámaso; Lambertucci, Guillermo W.; Sánchez-Zapata, José A.; Hiraldo, Fernando; Donázar, José A.

    2014-01-01

    Because large species ingest proportionally less food than small ones, it may be predicted that they should incorporate relatively fewer carotenoids to a proportionally equal volume of blood. However, some species may increase their levels of circulating carotenoids by ingesting unusual food. We tested whether the plasma concentration of carotenoids scales to the three-quarter power of mass in nine predatory and scavenger raptor species. No significant allometric relationships were found due ...

  1. Carotenoids in Aquaculture: Fish and Crustaceans

    Science.gov (United States)

    Bjerkeng, Bjorn

    This Chapter deals with selected topics on the use of carotenoids for colouration in aquaculture and incudes examples from ecological studies which support our understanding of functions and actions of carotenoids and colouration in fishes and crustaceans. Animal colours may be physical or structural in origin [1], e.g. Tyndall blues and iridescent diffraction colours, or they may be due to pigments, including carotenoids (Chapter 10).

  2. Carotenoids in Algae: Distributions, Biosyntheses and Functions

    OpenAIRE

    Shinichi Takaichi

    2011-01-01

    For photosynthesis, phototrophic organisms necessarily synthesize not only chlorophylls but also carotenoids. Many kinds of carotenoids are found in algae and, recently, taxonomic studies of algae have been developed. In this review, the relationship between the distribution of carotenoids and the phylogeny of oxygenic phototrophs in sea and fresh water, including cyanobacteria, red algae, brown algae and green algae, is summarized. These phototrophs contain division- or class-specific carote...

  3. Fermentative production of carotenoids from marine actinomycetes

    Directory of Open Access Journals (Sweden)

    B Ashokkumar

    2009-12-01

    Full Text Available Background and Objectives: In marine actinomycetes, carotenoid production occurs in constitutive, light-dependent or cryptic manner. The present work deals with the fermentative production of carotenoids from marine actinomycetes."nMaterials and Methods: Marine actinomycetes namely Streptomyces strain AQBMM35 was isolated from the marine sponge Mycale mytilorum collected from South West coast of India using ISP media. The Streptomyces isolates were characterized for their colony characteristics, morphological properties, physiological and biochemical properties and were tentatively identified. Fermentation of the strain under fluorescent white light was carried out for the production of carotenoids. UV spectrum, TLC and HPLC analysis were done for the confirmation of carotenoids."nResults: The characteristics studied strongly suggest that the strain AQBMM35 belongs to the genus Streptomyces sp. It has been found that Streptomyces strain (AQBMM35 fermenting under fluorescent white light produced carotenoids. Spectrophotometric analysis of the carotenoid fraction revealed a peak at 280 nm. TLC analysis of the carotenoid extract showed the presence of phytoene (Rf of 0.81. HPLC confirmed the production of phytoene when compared with standards."nConclusion: The fermenting sponge-associated Streptomyces isolate (AQBMM35 produced carotenoids namely phytoene. If this symbiotic Streptomyces strain, from which secondary metabolite like carotenoids are derived, can be cultured under light, then it can be used for mass production of precursor pigment and it can be used as an antioxidant and also as a food additive.

  4. Regulation of Carotenoid Biosynthesis During Fruit Development.

    Science.gov (United States)

    Lado, Joanna; Zacarías, Lorenzo; Rodrigo, María Jesús

    2016-01-01

    Carotenoids are recognized as the main pigments in most fruit crops, providing colours that range from yellow and pink to deep orange and red. Moreover, the edible portion of widely consumed fruits or their derived products represent a major dietary source of carotenoids for animals and humans. Therefore, these pigments are crucial compounds contributing to fruit aesthetic and nutritional quality but may also have protecting and ecophysiological functions in coloured fruits. Among plant organs, fruits display one of the most heterogeneous carotenoids patterns in terms of diversity and abundance. In this chapter a comprehensive list of the carotenoid content and profile in the most commonly cultivated fleshy fruits is reported. The proposed fruit classification systems attending to carotenoid composition are revised and discussed. The regulation of carotenoids in fruits can be rather complex due to the dramatic changes in content and composition during ripening, which are also dependent on the fruit tissue and the developmental stage. In addition, carotenoid accumulation is a dynamic process, associated with the development of chromoplasts during ripening. As a general rule, carotenoid accumulation is highly controlled at the transcriptional level of the structural and accessory proteins of the biosynthetic and degradation pathways, but other mechanisms such as post-transcriptional modifications or the development of sink structures have been recently revealed as crucial factors in determining the levels and stability of these pigments. In this chapter common key metabolic reactions regulating carotenoid composition in fruit tissues are described in addition to others that are restricted to certain species and generate unique carotenoids patterns. The existence of fruit-specific isoforms for key steps such as the phytoene synthase, lycopene β-cyclases or catabolic carotenoid cleavage dioxygenases has allowed an independent regulation of the pathway in fruit tissues

  5. Role of intermediary cells in Peltodon radicans (Lamiaceae) in the transfer of calcium and formation of calcium oxalate crystals

    OpenAIRE

    Elder Antônio Sousa Paiva; Silvia Rodrigues Machado

    2005-01-01

    With the objective of studying the connection between calcium oxalate crystals formation and the phloem, fragments of leaves of Peltodon radicans Pohl (Lamiaceae) were fixed and processed, for light and electron-transmission microscopes. It was observed that the crystals occurred in the cells of the bundle sheath, juxtaposed in relation to the phloem. Intermediary cells established a connection between the sieve element and crystal-bearing sheath cells. Calcium was present abundantly in the c...

  6. Crystal structure of listeriolysin O reveals molecular details of oligomerization and pore formation

    Science.gov (United States)

    Köster, Stefan; van Pee, Katharina; Hudel, Martina; Leustik, Martin; Rhinow, Daniel; Kühlbrandt, Werner; Chakraborty, Trinad; Yildiz, Özkan

    2014-04-01

    Listeriolysin O (LLO) is an essential virulence factor of Listeria monocytogenes that causes listeriosis. Listeria monocytogenes owes its ability to live within cells to the pH- and temperature-dependent pore-forming activity of LLO, which is unique among cholesterol-dependent cytolysins. LLO enables the bacteria to cross the phagosomal membrane and is also involved in activation of cellular processes, including the modulation of gene expression or intracellular Ca2+ oscillations. Neither the pore-forming mechanism nor the mechanisms triggering the signalling processes in the host cell are known in detail. Here, we report the crystal structure of LLO, in which we identified regions important for oligomerization and pore formation. Mutants were characterized by determining their haemolytic and Ca2+ uptake activity. We analysed the pore formation of LLO and its variants on erythrocyte ghosts by electron microscopy and show that pore formation requires precise interface interactions during toxin oligomerization on the membrane.

  7. Spontaneous Formation of Eutectic Crystal Structures in Binary and Ternary Charged Colloids due to Depletion Attraction.

    Science.gov (United States)

    Toyotama, Akiko; Okuzono, Tohru; Yamanaka, Junpei

    2016-01-01

    Crystallization of colloids has extensively been studied for past few decades as models to study phase transition in general. Recently, complex crystal structures in multi-component colloids, including alloy and eutectic structures, have attracted considerable attention. However, the fabrication of 2D area-filling colloidal eutectics has not been reported till date. Here, we report formation of eutectic structures in binary and ternary aqueous colloids due to depletion attraction. We used charged particles + linear polyelectrolyte systems, in which the interparticle interaction could be represented as a sum of the electrostatic, depletion, and van der Waals forces. The interaction was tunable at a lengthscale accessible to direct observation by optical microscopy. The eutectic structures were formed because of interplay of crystallization of constituent components and accompanying fractionation. An observed binary phase diagram, defined by a mixing ratio and inverse area fraction of the particles, was analogous to that for atomic and molecular eutectic systems. This new method also allows the adjustment of both the number and wavelengths of Bragg diffraction peaks. Furthermore, these eutectic structures could be immobilized in polymer gel to produce self-standing materials. The present findings will be useful in the design of the optical properties of colloidal crystals. PMID:26984298

  8. Spontaneous Formation of Eutectic Crystal Structures in Binary and Ternary Charged Colloids due to Depletion Attraction

    Science.gov (United States)

    Toyotama, Akiko; Okuzono, Tohru; Yamanaka, Junpei

    2016-03-01

    Crystallization of colloids has extensively been studied for past few decades as models to study phase transition in general. Recently, complex crystal structures in multi-component colloids, including alloy and eutectic structures, have attracted considerable attention. However, the fabrication of 2D area-filling colloidal eutectics has not been reported till date. Here, we report formation of eutectic structures in binary and ternary aqueous colloids due to depletion attraction. We used charged particles + linear polyelectrolyte systems, in which the interparticle interaction could be represented as a sum of the electrostatic, depletion, and van der Waals forces. The interaction was tunable at a lengthscale accessible to direct observation by optical microscopy. The eutectic structures were formed because of interplay of crystallization of constituent components and accompanying fractionation. An observed binary phase diagram, defined by a mixing ratio and inverse area fraction of the particles, was analogous to that for atomic and molecular eutectic systems. This new method also allows the adjustment of both the number and wavelengths of Bragg diffraction peaks. Furthermore, these eutectic structures could be immobilized in polymer gel to produce self-standing materials. The present findings will be useful in the design of the optical properties of colloidal crystals.

  9. Controlling competition between crystallization and glass formation in binary colloids with an external field

    International Nuclear Information System (INIS)

    The mechanism by which a liquid may become arrested, forming a glass, is a long-standing problem. So far no clear structural mechanism has been found. One promising approach is to use real space analysis of colloidal dispersions at the single-particle level to reveal local structural details which are inaccessible to many experimental techniques. Here we report a simple method to control glass formation which enables us to tackle the competition between crystallization and vitrification. While monodisperse colloidal hard spheres may readily crystallize, polydisperse suspensions tend to form glassy structures. We exploit the difference in sedimentation velocities of colloidal particles of different sizes, leading to a sediment which changes continuously in composition as a function of height, revealing glassy and crystalline states

  10. Formation Mechanism of Guided Resonances and Bound States in the Continuum in Photonic Crystal Slabs

    CERN Document Server

    Gao, Xingwei; Zhen, Bo; Lin, Xiao; Joannopoulos, John D; Soljačić, Marin; Chen, Hongsheng

    2016-01-01

    We develop a formalism, based on the mode expansion method, to describe the guided resonances and bound states in the continuum (BICs) in photonic crystal slabs with one-dimensional periodicity. This approach provides analytic insights to the formation mechanisms of these states: the guided resonances arise from the transverse Fabry-P\\'erot condition, and the divergence of the resonance lifetimes at the BICs is explained by a destructive interference of radiation from different propagating components inside the slab. We show BICs at the center and on the edge of the Brillouin zone protected by symmetry, as well as BICs at generic wave vectors not protected by symmetry.

  11. Excited-state properties of hydrophilic carotenoids

    Czech Academy of Sciences Publication Activity Database

    Chábera, P.; Naqvi, K.R.; Melo, T.B.; Sliwka, H.R.; Partali, V.; Lockwood, S.; Nodolski, G.; Polívka, Tomáš

    Nové Hrady : Academic and University Center, 2008. s. 40. [ESF Workshop on Novel Methods in Exploring Carotenoid Excited State Dynamics. 21.09.2008-25.09.2008, Nové Hrady] Institutional research plan: CEZ:AV0Z50510513 Keywords : carotenoids * biophysics Subject RIV: BO - Biophysics

  12. Apocarotenoids: A New Carotenoid-Derived Pathway.

    Science.gov (United States)

    Beltran, Juan Camilo Moreno; Stange, Claudia

    2016-01-01

    Carotenoids are precursors of carotenoid derived molecules termed apocarotenoids, which include isoprenoids with important functions in plant-environment interactions such as the attraction of pollinators and the defense against pathogens and herbivores. Apocarotenoids also include volatile aromatic compounds that act as repellents, chemoattractants, growth simulators and inhibitors, as well as the phytohormones abscisic acid and strigolactones. In plants, apocarotenoids can be found in several types of plastids (etioplast, leucoplast and chromoplast) and among different plant tissues such as flowers and roots. The structural similarity of some flower and spice isoprenoid volatile organic compounds (β-ionone and safranal) to carotenoids has led to the recent discovery of carotenoid-specific cleavage oxygenases, including carotenoid cleavage dioxygenases and 9-cis-epoxydioxygenases, which tailor and transform carotenoids into apocarotenoids. The great diversity of apocarotenoids is a consequence of the huge amount of carotenoid precursors, the variations in specific cleavage sites and the modifications after cleavage. Lycopene, β-carotene and zeaxanthin are the precursors of the main apocarotenoids described to date, which include bixin, crocin, picrocrocin, abscisic acid, strigolactone and mycorradicin.The current chapter will give rise to an overview of the biosynthesis and function of the most important apocarotenoids in plants, as well as the current knowledge about the carotenoid cleavage oxygenase enzymes involved in these biosynthetic pathways. PMID:27485225

  13. Method of producing purified carotenoid compounds

    Science.gov (United States)

    Eggink, Laura (Inventor)

    2007-01-01

    A method of producing a carotenoid in solid form includes culturing a strain of Chlorophyta algae cells in a minimal inorganic medium and separating the algae comprising a solid form of carotenoid. In one embodiment f the invention, the strain of Chlorophyta algae cells includes a strain f Chlamydomonas algae cells.

  14. Carotenoid metabolism and regulation in horticultural crops

    Science.gov (United States)

    Carotenoids are a diverse group of pigments widely distributed in nature. The vivid yellow, orange, and red colors in many horticultural crops attribute to overaccumulation of carotenoids, which contribute to a critical agronomic trait for flowers and an important quality trait for fruits and vegeta...

  15. The Role of Carotenoids in Human Skin

    Directory of Open Access Journals (Sweden)

    Theognosia Vergou

    2011-12-01

    Full Text Available The human skin, as the boundary organ between the human body and the environment, is under the constant influence of free radicals (FR, both from the outside in and from the inside out. Carotenoids are known to be powerful antioxidant substances playing an essential role in the reactions of neutralization of FR (mainly reactive oxygen species ROS. Carotenoid molecules present in the tissue are capable of neutralizing several attacks of FR, especially ROS, and are then destroyed. Human skin contains carotenoids, such as α-, γ-, β-carotene, lutein, zeaxanthin, lycopene and their isomers, which serve the living cells as a protection against oxidation. Recent studies have reported the possibility to investigate carotenoids in human skin quickly and non-invasively by spectroscopic means. Results obtained from in-vivo studies on human skin have shown that carotenoids are vital components of the antioxidative protective system of the human skin and could serve as marker substances for the overall antioxidative status. Reflecting the nutritional and stress situation of volunteers, carotenoids must be administered by means of antioxidant-rich products, e.g., in the form of fruit and vegetables. Carotenoids are degraded by stress factors of any type, inter alia, sun radiation, contact with environmental hazards, illness, etc. The kinetics of the accumulation and degradation of carotenoids in the skin have been investigated.

  16. Marine Carotenoids: Biological Functions and Commercial Applications

    NARCIS (Netherlands)

    Vilchez, C.; Forján, E.; Cuaresma, M.; Bédmar, F.; Garbayo, I.; Vega, J.M.

    2011-01-01

    Carotenoids are the most common pigments in nature and are synthesized by all photosynthetic organisms and fungi. Carotenoids are considered key molecules for life. Light capture, photosynthesis photoprotection, excess light dissipation and quenching of singlet oxygen are among key biological functi

  17. Experimental evidence for the participation of deep eutectic solvents in silver chloride crystal formation at low temperature

    Science.gov (United States)

    Bhatt, Jitkumar; Mondal, Dibyendu; Prasad, Kamalesh

    2016-05-01

    Deep eutectic solvents (DESs) obtained by the complexation of choline chloride (ChoCl) as hydrogen bond acceptor and hydrogen bond donors such as ethylene glycol (ChoCl-EG 1:2) and glycerol (ChoCl-Gly 1:2) were used as media for the formation of AgCl crystals. Although formation of AgCl crystals was observed in both the solvents but the rate of formation of crystals was faster in ChoCl-EG 1:2 at low temperature (4-5 °C). In the crystals, cholinium cations were found to be present with chloride ions bridged with Ag ions resulting generation of 1D network of AgCl2 anions.

  18. Carotenoid Metabolism: Biosynthesis, Regulation,and Beyond

    Institute of Scientific and Technical Information of China (English)

    Shan Lu; Li Li

    2008-01-01

    Carotenoids are Indispensable to plants and play a critical role in human nutrition and health. Significant progress has been made in our understanding of carotenoid metabolism in plants. The biosynthetic pathway has been extensively studied.Nearly all the genes encoding the biosynthetic enzymes have been isolated and characterized from various organisms. In recent years, there is an increasing body of work on the signaling pathways and plastid development, which might provide global control of carotenoid biosynthesis and accumulation. Herein, we will highlight recent progress on the biosynthesis,regulation, and metabolic engineering of carotenoids in plants, as well as the future research towards elucidating the regulatory mechanisms and metabolic network that control carotenoid metabolism.

  19. The intake of carotenoids in Denmark

    DEFF Research Database (Denmark)

    Leth, Torben; Jakobsen, Jette; Andersen, N. L.

    2000-01-01

    To estimate the intake of carotenoids in the Danish population Danish fruits and vegetables were screened with an HPLC method consisting of extraction with ethanol:tetrahydrofuran, separation by reversed phase HPLC with the mobile phase acetonitril:methanol:dichlormethan, triethylamin, BHT...... in the foods the mean intake and intake distribution of the carotenoids were calculated. Carrots and tomatoes have both high contents of carotenoids (8,450 mu g/100 g alpha- + beta-carotene and 4,790 mu g/100 g lycopene, respectively) and high intakes (19 and 15 g/day, respectively) and were responsible for 47......% and 32%, respectively, of the mean intake of carotenoids of 4.8 mg/day A median value of 4.1 mg/day was found indicating skewed intake distributions. The difference between men and women was 0.4 mg/day (p carotenoids, alpha-carotene, beta-carotene, lutein and lycopene, contributed...

  20. Formation of Polymer Networks for Fast In-Plane Switching of Liquid Crystals at Low Temperatures

    Science.gov (United States)

    Yu, Byeong-Hun; Song, Dong Han; Kim, Ki-Han; Wok Park, Byung; Choi, Sun-Wook; Park, Sung Il; Kang, Sung Gu; Yoon, Jeong Hwan; Kim, Byeong Koo; Yoon, Tae-Hoon

    2013-09-01

    We formed a polymer structure to enable fast in-plane switching of liquid crystals at low temperatures. The problem of the inevitable slow response at low temperatures was reduced by the formation of in-cell polymer networks in in-plane switching (IPS) cells. The electro-optic characteristics of polymer-networked IPS cells were measured at temperatures ranging from -10 to 20 °C. The turn-on and turn-off times of an IPS cell were reduced by 44.5 and 47.2% at -10 °C by the formation of polymer networks. We believe that the proposed technology can be applied to emerging display devices such as mobile phones and automotive displays that may be used at low temperatures.

  1. Detergent-Mediated Formation of β-Hematin: Heme Crystallization Promoted by Detergents Implicates Nanostructure Formation for Use as a Biological Mimic

    Science.gov (United States)

    2016-01-01

    Hemozoin is a unique biomineral that results from the sequestration of toxic free heme liberated as a consequence of hemoglobin degradation in the malaria parasite. Synthetic neutral lipid droplets (SNLDs) and phospholipids were previously shown to support the rapid formation of β-hematin, abiological hemozoin, under physiologically relevant pH and temperature, though the mechanism by which heme crystallization occurs remains unclear. Detergents are particularly interesting as a template because they are amphiphilic molecules that spontaneously organize into nanostructures and have been previously shown to mediate β-hematin formation. Here, 11 detergents were investigated to elucidate the physicochemical properties that best recapitulate crystal formation in the parasite. A strong correlation between the detergent’s molecular structure and the corresponding kinetics of β-hematin formation was observed, where higher molecular weight polar chains promoted faster reactions. The larger hydrophilic chains correlated to the detergent’s ability to rapidly sequester heme into the lipophilic core, allowing for crystal nucleation to occur. The data presented here suggest that detergent nanostructures promote β-hematin formation in a similar manner to SNLDs and phospholipids. Through understanding mediator properties that promote optimal crystal formation, we are able to establish an in vitro assay to probe this drug target pathway. PMID:27175104

  2. Geographical trends in the yolk carotenoid composition of the pied flycatcher (Ficedula hypoleuca).

    Science.gov (United States)

    Eeva, Tapio; Ruuskanen, Suvi; Salminen, Juha-Pekka; Belskii, Eugen; Järvinen, Antero; Kerimov, Anvar; Korpimäki, Erkki; Krams, Indrikis; Moreno, Juan; Morosinotto, Chiara; Mänd, Raivo; Orell, Markku; Qvarnström, Anna; Siitari, Heli; Slater, Fred M; Tilgar, Vallo; Visser, Marcel E; Winkel, Wolfgang; Zang, Herwig; Laaksonen, Toni

    2011-02-01

    Carotenoids in the egg yolks of birds are considered to be important antioxidants and immune stimulants during the rapid growth of embryos. Yolk carotenoid composition is strongly affected by the carotenoid composition of the female's diet at the time of egg formation. Spatial and temporal differences in carotenoid availability may thus be reflected in yolk concentrations. To assess whether yolk carotenoid concentrations or carotenoid profiles show any large-scale geographical trends or differences among habitats, we collected yolk samples from 16 European populations of the pied flycatcher, Ficedula hypoleuca. We found that the concentrations and proportions of lutein and some other xanthophylls in the egg yolks decreased from Central Europe northwards. The most southern population (which is also the one found at the highest altitude) also showed relatively low carotenoid levels. Concentrations of β-carotene and zeaxanthin did not show any obvious geographical gradients. Egg yolks also contained proportionally more lutein and other xanthophylls in deciduous than in mixed or coniferous habitats. We suggest that latitudinal gradients in lutein and xanthophylls reflect the lower availability of lutein-rich food items in the northern F. hypoleuca populations and in montane southern populations, which start egg-laying earlier relative to tree phenology than the Central European populations. Similarly, among-habitat variation is likely to reflect the better availability of lutein-rich food in deciduous forests. Our study is the first to indicate that the concentration and profile of yolk carotenoids may show large-scale spatial variation among populations in different parts of the species' geographical range. Further studies are needed to test the fitness effects of this geographical variation. PMID:20848135

  3. Liquid-Liquid Phase Separation in Supersaturated Lysozyme Solutions and Associated Precipitate Formation/Crystallization

    Science.gov (United States)

    Muschol, Martin; Rosenberger, Franz

    1997-01-01

    Using cloud point determinations, the phase boundaries (binodals) for metastable liquid-liquid (L-L) separation in supersaturated hen egg white lysozyme solutions with 3%, 5%, and 7% (wlv) NaCl at pH= 4.5 and protein concentrations c between 40 and 400 mg/ml were determined. The critical temperature for the binodal increased approximately linearly with salt concentration. The coexisting liquid phases both remained supersaturated but differed widely in protein concentration. No salt repartitioning was observed between the initial and the two separated liquid phases. After the L-L separation, due to the presence of the high protein concentration phase, crystallization occurred much more rapidly than in the initial solution. At high initial protein concentrations, a metastable gel phase formed at temperatures above the liquid binodal. Both crystal nucleation and gel formation were accelerated in samples that had been cycled through the binodal. Solutions in the gel and L-L regions yielded various types of precipitates. Based on theoretical considerations, previous observations with other proteins, and our experimental results with lysozyme, a generic phase diagram for globular proteins is put forth. A limited region in the (T,c) plane favorable for the growth of protein single crystals is delineated.

  4. Free radical formation in crystals of guanine hydrochloride dihydrate: an ESR and ENDOR study

    International Nuclear Information System (INIS)

    Radiation-induced free radical formation in single crystals of guanine hydrochloride dihydrate has been studied at temperatures between 20 and 300 K using ESR and ENDOR spectroscopy. At low temperatures three radical species are trapped. Two of these are the C8 H-addition radical R1 previously analysed by Alexander and Gordy (1967) and the O6-protonated anion radical R2. The third species (R4) remains unidentified. Upon annealing at 280 K for an extended period the protonated anion R2 transforms into a new radical R3 which exhibits a well-defined hyperfine pattern but still could not be identified unambiguously. Also radical R4 probably transforms into a new radical (R5) upon such treatment. One proton coupling due to R5 was detected. A scheme of radical reactions incorporating these five radicals is proposed. This scheme also suggests that differences in radical formation between the monohydrate and dihydrate crystals of guanine hydrochloride depends upon differences in the hydrogen bonding network. (author)

  5. Quasicrystal formation, phase selection and crystallization kinetics in Zr-Cu-Ni-Al based metallic glasses

    International Nuclear Information System (INIS)

    Quaternary Zr-Cu-Ni-Al is one of the best glass forming alloys known. In a narrow concentration range icosahedral quasicrystals are formed upon annealing; in Zr69.5Cu12Ni11Al7.5 the metastable primitive icosahedral phase is probably oxygen stabilized. At slightly higher oxygen contents (about 1 at.%) the formation of a metastable fcc ''big-cube'' phase (NiTi2-type) is competing with very high nucleation rates. The aim of this paper is to investigate in detail the formation of quasicrystals as well as microstructures consisting of the ''big-cube'' phase in order to design in particular nanocrystalline structures by controlled crystallization. Nucleation rates were measured by means of crystallization statistics. By modeling the obtained nucleation rates in the framework of diffusion controlled classical nucleation interfacial energies as well as melting temperatures for the metastable phases could be derived. Atomic mobility was estimated from growth data. Using these data TTT-diagrams can be drawn and microstructures (for example nanocrystalline) predicted. The phase selection during the formation of the metastable structures was observed to depend strongly not only on the exchange of the Zr by Hf or Ti, but also on the late transition elements chosen, hydrogen or oxygen contamination as well as on alloying with small amounts of other elements for example Si, Sn, Y or Mo. Regarding the influence of the late transition metals there is some evidence that the quasicrystals are a hybrid of two structural elements, i.e. the tetragonal Zr2Ni(Al2Cu) and the tetragonal Zr2Cu (MoSi2) structure. The mentioned alloying elements as well as oxygen and hydrogen are assumed to influence the arrangement of the structural elements towards one or the other structure. (orig.)

  6. Structures and Analysis of Carotenoid Molecules.

    Science.gov (United States)

    Rodriguez-Amaya, Delia B

    2016-01-01

    Modifications of the usual C40 linear and symmetrical carotenoid skeleton give rise to a wide array of structures of carotenes and xanthophylls in plant tissues. These include acyclic, monocyclic and dicyclic carotenoids, along with hydroxy and epoxy xanthophylls and apocarotenoids. Carotenols can be unesterified or esterified (monoester) in one or two (diester) hydroxyl groups with fatty acids. E-Z isomerization increases the array of possible plant carotenoids even further. Screening and especially quantitative analysis are being carried out worldwide. Visible absorption spectrometry and near infrared reflectance spectroscopy have been used for the initial estimation of the total carotenoid content or the principal carotenoid content when large numbers of samples needed to be analyzed within a short time, as would be the case in breeding programs. Although inherently difficult, quantitative analysis of the individual carotenoids is essential. Knowledge of the sources of errors and means to avoid them has led to a large body of reliable quantitative compositional data on carotenoids. Reverse-phase HPLC with a photodiode array detector has been the preferred analytical technique, but UHPLC is increasingly employed. HPLC-MS has been used mainly for identification and NMR has been useful in unequivocally identifying geometric isomers. PMID:27485219

  7. Carotenoid Photoprotection in Artificial Photosynthetic Antennas

    Energy Technology Data Exchange (ETDEWEB)

    Kloz, Miroslav [VU Univ., Amsterdam (Netherlands); Pillai, Smitha [Arizona State Univ., Tempe, AZ (United States); Kodis, Gerdenis [Arizona State Univ., Tempe, AZ (United States); Gust, Devens [Arizona State Univ., Tempe, AZ (United States); Moore, Thomas A. [Arizona State Univ., Tempe, AZ (United States); Moore, Ana L. [Arizona State Univ., Tempe, AZ (United States); van Grondelle, Rienk [VU Univ., Amsterdam (Netherlands); Kennis, John T. M. [VU Univ., Amsterdam (Netherlands)

    2011-04-14

    A series of phthalocyanine-carotenoid dyads in which a phenylamino group links a phthalocyanine to carotenoids having 8-11 backbone double bonds were examined by visible and near-infrared femtosecond pump-probe spectroscopy combined with global fitting analysis. The series of molecules has permitted investigation of the role of carotenoids in the quenching of excited states of cyclic tetrapyrroles. The transient behavior varied dramatically with the length of the carotenoid and the solvent environment. Clear spectroscopic signatures of radical species revealed photoinduced electron transfer as the main quenching mechanism for all dyads dissolved in a polar solvent (THF), and the quenching rate was almost independent of carotenoid length. However, in a nonpolar solvent (toluene), quenching rates displayed a strong dependence on the conjugation length of the carotenoid and the mechanism did not include charge separation. The lack of any rise time components of a carotenoid S1 signature in all experiments in toluene suggests that an excitonic coupling between the carotenoid S1 state and phthalocyanine Q state, rather than a conventional energy transfer process, is the major mechanism of quenching. A pronounced inhomogeneity of the system was observed and attributed to the presence of a phenyl-amino linker between phthalocyanine and carotenoids. On the basis of accumulated work on various caroteno-phthalocyanine dyads and triads, we have now identified three mechanisms of tetrapyrrole singlet excited state quenching by carotenoids in artificial systems: (i) Car-Pc electron transfer and recombination; (ii)1Pc to Car S1 energy transfer and fast internal conversion to the Car ground state; (iii) excitonic coupling between 1Pc and Car S1 and ensuing internal conversion to the ground state of the carotenoid. The dominant mechanism depends upon the exact molecular architecture and solvent environment

  8. Recombinant formate dehydrogenase from Arabidopsis thaliana: Preparation, crystal growth in microgravity, and preliminary X-ray diffraction study

    International Nuclear Information System (INIS)

    Crystals of high-purity recombinant NAD+-dependent formate dehydrogenase from the higher plant Arabidopsis thaliana (AraFDH) were grown in microgravity in the Modul'-1 protein crystallization apparatus on the International Space Station. The space-grown crystals have larger sizes than those grown on Earth. X-ray diffraction data suitable for determining the three-dimensional structure were collected from the space-grown crystals to a resolution of 1.22 A using an X-ray synchrotron source. The crystals belong to sp. gr. P43212; the unit-cell parameters are a = b = 107.865 A, c = 71.180 A, α = β = γ = 90 deg.

  9. Holographic films from carotenoid pigments

    Science.gov (United States)

    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.

  10. Carotenoid maintenance handicap and the physiology of carotenoid-based signalisation of health

    Science.gov (United States)

    Vinkler, Michal; Albrecht, Tomáš

    2010-01-01

    Despite a reasonable scientific interest in sexual selection, the general principles of health signalisation via ornamental traits remain still unresolved in many aspects. This is also true for the mechanism preserving honesty of carotenoid-based signals. Although it is widely accepted that this type of ornamentation reflects an allocation trade-off between the physiological utilisation of carotenoids (mainly in antioxidative processes) and their deposition in ornaments, some recent evidence suggests more complex interactions. Here, we further develop the models currently proposed to explain the honesty of carotenoid-based signalisation of heath status by adding the handicap principle concept regulated by testosterone. We propose that under certain circumstances carotenoids may be dangerous for the organism because they easily transform into toxic cleavage products. When reserves of other protective antioxidants are insufficient, physiological trade-offs may exist between maintenance of carotenoids for ornament expression and their removal from the body. Furthermore, we suggest that testosterone which enhances ornamentation by increasing carotenoid bioavailability may also promote oxidative stress and hence lower antioxidant reserves. The presence of high levels of carotenoids required for high-quality ornament expression may therefore represent a handicap and only individuals in prime health could afford to produce elaborate colourful ornaments. Although further testing is needed, this ‘carotenoid maintenance handicap’ hypothesis may offer a new insight into the physiological aspects of the relationship between carotenoid function, immunity and ornamentation.

  11. Availability of non-carotenoid antioxidants affects the expression of a carotenoid-based sexual ornament.

    Science.gov (United States)

    Pike, Thomas W; Blount, Jonathan D; Lindström, Jan; Metcalfe, Neil B

    2007-08-22

    Carotenoids are responsible for much of the yellow, orange and red pigmentation in the animal kingdom, and the importance of such coloration as an honest signal of individual quality has received widespread attention. In particular, owing to the multiple roles of carotenoids as pigments, antioxidants and immunostimulants, carotenoid-based coloration has been suggested to advertise an individual's antioxidant or immune defence capacity. However, it has recently been argued that carotenoid-based signals may in fact be advertising the availability of different antioxidants, many of which (including various vitamins, antioxidant enzymes and minerals) are colourless and so would be uninformative as components of a visual signal, yet often have greater biological activity than carotenoids. We tested this hypothesis by feeding male sticklebacks (Gasterosteus aculeatus) a diet containing a fixed level of carotenoids and either low or high, but biologically realistic levels of the colourless antioxidant vitamins C and E. High-antioxidant diet males produced significantly more intensely coloured (but not larger) carotenoid-based regions of nuptial coloration and were preferred over size-matched males of the opposite diet treatment in mate-choice trials. Furthermore, there were positive correlations between an individual's somatic antioxidant activity and signal intensity. Our data suggest that carotenoid-based ornaments may honestly signal an individual's availability of non-carotenoid antioxidants, allowing females to make adaptive mate-choice decisions. PMID:17472903

  12. Diversity in the carotenoid profiles and the expression of genes related to carotenoid accumulation among citrus genotypes

    OpenAIRE

    Ikoma, Yoshinori; Matsumoto, Hikaru; Kato, Masaya

    2016-01-01

    Carotenoids are not only important to the plants themselves but also are beneficial to human health. Since citrus fruit is a good source of carotenoids for the human diet, it is important to study carotenoid profiles and the accumulation mechanism in citrus fruit. Thus, in the present paper, we describe the diversity in the carotenoid profiles of fruit among citrus genotypes. In regard to carotenoids, such as β-cryptoxanthin, violaxanthin, lycopene, and β-citraurin, the relationship between t...

  13. Crystal structures and in-situ formation study of mayenite electrides.

    Science.gov (United States)

    Palacios, Luis; De La Torre, Angeles G; Bruque, Sebastián; García-Muñoz, Jose L; García-Granda, Santiago; Sheptyakov, Denis; Aranda, Miguel A G

    2007-05-14

    Mayenite inorganic electrides are antizeolite nanoporous materials with variable electron concentration [Ca12Al14O32]2+ square5-deltaO1-delta2-e2delta- (0 crystal structure contains positively charged cages where loosely bounded oxide anions are located. These oxygens can be removed to yield electron-loaded materials in which the electrons behave like anions (electrides). Here, a new preparation method, which allows synthesizing powder mayenite electrides easily, is reported. Accurate structural data for the white (delta = 0) and green electride (delta approximately 0.5) are reported from joint Rietveld refinements of neutron and synchrotron X-ray powder diffraction data and also from single-crystal diffraction. The electride formation at high temperature under vacuum has been followed in-situ by neutron powder diffraction. The evolution of mayenite crystal structure, including the changes in the key occupation factor of the intracage oxide anions, is reported. Furthermore, the stability of mayenite framework in very low oxygen partial pressure conditions is also studied. It has been found that C12A7 decomposes, at 1373 K in reducing conditions, to give Ca5Al6O14 (C5A3) and Ca3Al2O6 (C3A). The kinetics of this transformation has also been studied. The fit of the transformed fraction to the classic Avrami-Erofe'ev equation gave an "Avrami exponent", n = 2, which indicates that nucleation is fast and the two-dimensional linear growth of the new phases is likely to be the limiting factor. PMID:17432850

  14. Impacts of crystal metal on secondary aliphatic amine aerosol formation during dust storm episodes in Beijing

    Science.gov (United States)

    Liu, Qingyang; Bei, Yiling

    2016-03-01

    Trimethylamine (TMA) enters the atmosphere from a variety of sources and is a ubiquitous atmospheric organic base. The atmospheric reaction mechanism of TMA with key atmospheric oxidants is important to predict its distribution and environmental behavior in the particle phase. While previous studies have extensively focused on the production of particle amine salts (i.e. trimethylamine-N-oxide (TMAO)) using chamber experiments, the atmospheric behavior of TMAO in the environment is still poorly understood. Ambient fine particulate matter (PM2.5) was collected at two sampling sites in Beijing from March 10 to May 10, 2012. We analyzed the samples for water-soluble ions, crystal metals, TMA, and TMAO. Water-soluble ions (e.g. SO42-, NO3-, NH4+), TMA, and TMAO were measured using ion chromatography, while crystal metal (e.g. Al, Fe, Mn) in PM2.5 was quantified by inductively coupled plasma mass spectrometry (ICP-MS). Two dust storms (DS) occurred during the sampling period on March 28 and April 28. Mineral dust impacted PM2.5 mass and composition greatly during dust storm days, as it contributed approximately 1.2-4.0 times greater on dust storm days versus non-dust storm days. We found TMAO concentrations were highly associated with aluminum in PM2.5. Further, we applied the density functional theory (DFT) method to confirm that aluminum plays a catalytic effect in the reaction of TMA with ozone (O3). Our work improves understanding of the effect of crystal metals on secondary aliphatic amine aerosol formation in the atmosphere.

  15. Influence of dislocation structure and impurities on void lattice formation in crystals under irradiation

    International Nuclear Information System (INIS)

    The void ordering under irradiation in simple cubic, bcc, fcc and hcp-crystals is considered within the framework of the dislocation model of void lattice formation based upon the absorption of perfect interstitial loops by voids. The ordering criterion is derived taking into account not only perfect loopd but Frank sessile loops and straight dislocations as well. Analytical dependence of void lattice parameters on the concentration of the loop nucleation sites is derived. Impurities are shown to stimulate or prevent void ordering depending on their influence on the loop nature. Finally, a mechanism of loop-punching from submicroscopic overpressurized gas bubbles is considered as a possible source of perfect loops which could induce the swelling saturation and void ordering in fcc metals with low stacking fault energy. 15 refs.; 3 figs

  16. Proteomic changes in response to crystal formation in Drosophila Malpighian tubules.

    Science.gov (United States)

    Chung, Vera Y; Konietzny, Rebecca; Charles, Philip; Kessler, Benedikt; Fischer, Roman; Turney, Benjamin W

    2016-04-01

    Kidney stone disease is a major health burden with a complex and poorly understood pathophysiology. Drosophila Malpighian tubules have been shown to resemble human renal tubules in their physiological function. Herein, we have used Drosophila as a model to study the proteomic response to crystal formation induced by dietary manipulation in Malpighian tubules. Wild-type male flies were reared in parallel groups on standard medium supplemented with lithogenic agents: control, Sodium Oxalate (NaOx) and Ethylene Glycol (EG). Malpighian tubules were dissected after 2 weeks to visualize crystals with polarized light microscopy. The parallel group was dissected for protein extraction. A new method of Gel Assisted Sample Preparation (GASP) was used for protein extraction. Differentially abundant proteins (pcalcium or zinc ion binder. Among these, 11 candidate proteins were shortlisted in NaOx diet and 16 proteins in EG diet. We concluded that GASP is a proteomic sample preparation method that can be applied to individual Drosophila Malpighian tubules. Our results may further increase the understanding of the pathophysiology of human kidney stone disease. PMID:27064297

  17. Excited-state properties of hydrophilic carotenoids

    Czech Academy of Sciences Publication Activity Database

    Fuciman, M.; Chábera, P.; Naqvi, K.R.; Melo, T.B.; Sliwka, H.R.; Partali, V.; Lockwood, S.; Jackson, H.L.; Polívka, Tomáš

    - : -, 2009. s. 408. ISBN N. [International Conference on Photochemistry /24./. 19.07.2009-24.07.2009, Toledo] Institutional research plan: CEZ:AV0Z50510513 Keywords : carotenoids * excited-state dynamics * femtosecond spectroscopy Subject RIV: BO - Biophysics

  18. Regulation of Carotenoid Biosynthesis in Photosynthetic Organs.

    Science.gov (United States)

    Llorente, Briardo

    2016-01-01

    A substantial proportion of the dazzling diversity of colors displayed by living organisms throughout the tree of life is determined by the presence of carotenoids, which most often provide distinctive yellow, orange and red hues. These metabolites play fundamental roles in nature that extend far beyond their importance as pigments. In photosynthetic lineages, carotenoids are essential to sustain life, since they have been exploited to maximize light harvesting and protect the photosynthetic machinery from photooxidative stress. Consequently, photosynthetic organisms have evolved several mechanisms that adjust the carotenoid metabolism to efficiently cope with constantly fluctuating light environments. This chapter will focus on the current knowledge concerning the regulation of the carotenoid biosynthetic pathway in leaves, which are the primary photosynthetic organs of most land plants. PMID:27485221

  19. Latin American food sources of carotenoids.

    Science.gov (United States)

    Rodriguez-Amaya, D B

    1999-09-01

    Latin America has a wide variety of carotenogenic foods, notable for the diversity and high levels of carotenoids. A part of this natural wealth has been analyzed. Carrot, red palm oil and some cultivars of squash and pumpkin are sources of both beta-carotene and alpha-carotene. beta-carotene is the principal carotenoid of the palm fruits burití, tucumã and bocaiuva, other fruits such as loquat, marolo and West Indian cherry, and sweet potato. Buriti also has high amounts of alpha-carotene and gamma-carotene. beta-Cryptoxanthin is the major carotenoid in caja, nectarine, orange-fleshed papaya, orange, peach, tangerine and the tree tomato. Lycopene predominates in tomato, red-fleshed papaya, guava, pitanga and watermelon. Pitanga also has substantial amounts of beta-cryptoxanthin, gamma-carotene and rubixanthin. Zeaxanthin, principal carotenoid of corn, is also predominant only in piquí. delta-Carotene is the main carotenoid of the peach palm and zeta-carotene of passion fruit. Lutein and beta-carotene, in high concentrations, are encountered in the numerous leafy vegetables of the region, as well as in other green vegetables and in some varieties of squash and pumpkin. Violaxanthin is the principal carotenoid of mango and mamey and is also found in appreciable amounts in green vegetables. Quantitative, in some cases also qualitative, differences exist among cultivars of the same food. Generally, carotenoids are in greater concentrations in the peel than in the pulp, increase considerably during ripening and are in higher levels in foods produced in hot places. Other Latin America indigenous carotenogenic foods must be investigated before they are supplanted by introduced crops, which are often poorer sources of carotenoids. PMID:10971848

  20. Marine Carotenoids and Cardiovascular Risk Markers

    Directory of Open Access Journals (Sweden)

    Lorenza Speranza

    2011-06-01

    Full Text Available Marine carotenoids are important bioactive compounds with physiological activities related to prevention of degenerative diseases.found principally in plants, with potential antioxidant biological properties deriving from their chemical structure and interaction with biological membranes. They are substances with very special and remarkable properties that no other groups of substances possess and that form the basis of their many, varied functions and actions in all kinds of living organisms. The potential beneficial effects of marine carotenoids have been studied particularly in astaxanthin and fucoxanthin as they are the major marine carotenoids. Both these two carotenoids show strong antioxidant activity attributed to quenching singlet oxygen and scavenging free radicals. The potential role of these carotenoids as dietary anti-oxidants has been suggested to be one of the main mechanisms for their preventive effects against cancer and inflammatory diseases. The aim of this short review is to examine the published studies concerning the use of the two marine carotenoids, astaxanthin and fucoxanthin, in the prevention of cardiovascular diseases.

  1. Hillock formation of Pt thin films on single-crystal yttria-stabilized zirconia

    Science.gov (United States)

    Galinski, Henning; Ryll, Thomas; Schlagenhauf, Lukas; Gauckler, Ludwig J.; Stender, Patrick; Schmitz, Guido

    2012-03-01

    The stability of metal thin films on a dielectric substrate is conditioned by the magnitude of the interactive forces at the interface. In the case of a nonreactive interface and weak adhesion, the minimization of the free surface energy gives rise to an instability of the thin film. In order to study these effects, Pt thin films with a thickness of 50 nm were deposited via ion-beam sputtering on yttria-stabilized zirconia single crystals. All Pt films were subjected to heat treatments up to 973 K for 2 h. The morphological evolution of Pt thin films has been investigated by means of scanning electron microscopy, atomic force microscopy, and standard image analysis techniques. Three main observations have been made: (i) The deposition method has a direct impact on the morphological evolution of the film during annealing. Instead of hole formation, which is typically observed as a response to a thermal treatment, anisotropic pyramidal-shaped hillocks are formed on top of the film. (ii) It is shown by comparing the hillocks’ aspect ratio with finite element method simulations that the hillock formation can be assigned to a stress relaxation process inside the thin film. (iii) By measuring the quasiequilibrium shapes and the shape fluctuations of the formed Pt hillocks the anisotropy of the step free energy and its stiffness have been derived in addition to the anisotropic kink energy of the hillocks’ edges.

  2. Formation of oriented nickel aggregates in rutile single crystals by Ni implantation

    International Nuclear Information System (INIS)

    The magnetic and electrical properties of Ni implanted single crystalline TiO2 rutile were studied for nominal implanted fluences between 0.5×1017 cm−2 and 2.0×1017 cm−2 with 150 keV energy, corresponding to maximum atomic concentrations between 9 at% and 27 at% at 65 nm depth, in order to study the formation of metallic oriented aggregates. The results indicate that the as implanted crystals exhibit superparamagnetic behavior for the two higher fluences, which is attributed to the formation of nanosized nickel clusters with an average size related with the implanted concentration, while only paramagnetic behavior is observed for the lowest fluence. Annealing at 1073 K induces the aggregation of the implanted nickel and enhances the magnetization in all samples. The associated anisotropic behavior indicates preferred orientations of the nickel aggregates in the rutile lattice consistent with Rutherford backscattering spectrometry—channelling results. Electrical conductivity displays anisotropic behavior but no magnetoresistive effects were detected. - Author-Highlights: • Ni nano-aggregates were grown on TiO2 using Ni implantation with different fluences. • In the as implanted state, the aggregates size is a function of the implanted fluence. • Ni aggregates are oriented within the rutile structure-2 orientations are proposed

  3. Hemocytes participate in calcium carbonate crystal formation, transportation and shell regeneration in the pearl oyster Pinctada fucata.

    Science.gov (United States)

    Li, Shiguo; Liu, Yangjia; Liu, Chuang; Huang, Jingliang; Zheng, Guilan; Xie, Liping; Zhang, Rongqing

    2016-04-01

    In this study, light microscope, scanning and transmission electron microscope, hematoxylin-eosin and fluorescent staining, and mass spectrometry methods were employed to observe the calcium carbonate (CaCO3) crystal formation, hemocyte release and transportation, and hemocyte distribution at the shell regeneration area and to analyse the proteome of hemocytes in the pearl oyster, Pinctada fucata. The results indicated that intracellular CaCO3 crystals were observed in circulating hemocytes in P. fucata, implying that there was a suitable microenvironment for crystal formation in the hemocytes. This conclusion was further supported by the proteome analysis, in which various biomineralization-related proteins were detected. The crystal-bearing hemocytes, mainly granulocytes, may be released to extrapallial fluid (EPF) by the secretory cavities distributed on the outer surface of the mantle centre. These granulocytes in the EPF and between the regenerated shells were abundant and free. In the regenerated prismatic layer, the granulocytes were fused into each column and fragmented with the duration of shell maturation, suggesting the direct involvement of hemocytes in shell regeneration. Overall, this study provided evidence that hemocytes participated in CaCO3 crystal formation, transportation and shell regeneration in the pearl oyster. These results are helpful to further understand the exact mechanism of hemocyte-mediated biomineralization in shelled molluscs. PMID:26923245

  4. Effect of carotenoid structure on excited state dynamics of carbonyl carotenoids

    Czech Academy of Sciences Publication Activity Database

    Chábera, P.; Fuciman, M.; Hříbek, P.; Polívka, Tomáš

    Messina : Universitá di Messina, 2008. s. 53. [ESF Workshop on Ultrafast Excited-State Processes in Condensed Phases. 18.06.2008-21.06.2008, Santa Tecla] Institutional research plan: CEZ:AV0Z50510513 Keywords : carotenoids * carotenoid structure Subject RIV: BO - Biophysics

  5. Heterologous Carotenoid-Biosynthetic Enzymes: Functional Complementation and Effects on Carotenoid Profiles in Escherichia coli

    OpenAIRE

    Song, Gyu Hyeon; Kim, Se Hyeuk; Choi, Bo Hyun; Han, Se Jong; Lee, Pyung Cheon

    2013-01-01

    A limited number of carotenoid pathway genes from microbial sources have been studied for analyzing the pathway complementation in the heterologous host Escherichia coli. In order to systematically investigate the functionality of carotenoid pathway enzymes in E. coli, the pathway genes of carotenogenic microorganisms (Brevibacterium linens, Corynebacterium glutamicum, Rhodobacter sphaeroides, Rhodobacter capsulatus, Rhodopirellula baltica, and Pantoea ananatis) were modified to form syntheti...

  6. Diversity in the carotenoid profiles and the expression of genes related to carotenoid accumulation among citrus genotypes.

    Science.gov (United States)

    Ikoma, Yoshinori; Matsumoto, Hikaru; Kato, Masaya

    2016-01-01

    Carotenoids are not only important to the plants themselves but also are beneficial to human health. Since citrus fruit is a good source of carotenoids for the human diet, it is important to study carotenoid profiles and the accumulation mechanism in citrus fruit. Thus, in the present paper, we describe the diversity in the carotenoid profiles of fruit among citrus genotypes. In regard to carotenoids, such as β-cryptoxanthin, violaxanthin, lycopene, and β-citraurin, the relationship between the carotenoid profile and the expression of carotenoid-biosynthetic genes is discussed. Finally, recent results of quantitative trait locus (QTL) analyses of carotenoid contents and expression levels of carotenoid-biosynthetic genes in citrus fruit are shown. PMID:27069398

  7. A molecular and carbon isotopic study towards the origin and diagenetic fate of diaromatic carotenoids

    NARCIS (Netherlands)

    Sinninghe Damsté, J.S.; Hartgers, W.A.; Requejo, A.G.; Allan, J.; Hayes, J.M.; Ling, Y.; Xie, T.-M.; Primack, J.; Leeuw, J.W. de

    1994-01-01

    Pyrolysates of high-molecular-weight sedimentary fractions of the Duvernay Formation (Western Canada Basin) are dominated by 1,2,3,4- and 1,2,3,5-tetramethylbenzene, which, generated via beta-cleavage, indicate the presence of diaromatic carotenoids in the macromolecular aggregates. This was substan

  8. Spatial and temporal mapping of coke formation during paraffin and olefin aromatization in individual H-ZSM-5 crystals

    NARCIS (Netherlands)

    Chung, Y.M.; Mores, D.; Weckhuysen, B.M.

    2011-01-01

    The formation of carbonaceous deposits that occurs during the aromatization of C4–C7 paraffin and olefin hydrocarbons is visualized in a space- and time-resolved manner over individual micron-sized H-ZSM- 5 zeolite crystals. In situ UV–vis and confocal fluorescence micro-spectroscopy techniques are

  9. Carotenoid-enriched transgenic corn delivers bioavailable carotenoids to poultry and protects them against coccidiosis.

    Science.gov (United States)

    Nogareda, Carmina; Moreno, Jose A; Angulo, Eduardo; Sandmann, Gerhard; Portero, Manuel; Capell, Teresa; Zhu, Changfu; Christou, Paul

    2016-01-01

    Carotenoids are health-promoting organic molecules that act as antioxidants and essential nutrients. We show that chickens raised on a diet enriched with an engineered corn variety containing very high levels of four key carotenoids (β-carotene, lycopene, zeaxanthin and lutein) are healthy and accumulate more bioavailable carotenoids in peripheral tissues, muscle, skin and fat, and more retinol in the liver, than birds fed on standard corn diets (including commercial corn supplemented with colour additives). Birds were challenged with the protozoan parasite Eimeria tenella and those on the high-carotenoid diet grew normally, suffered only mild disease symptoms (diarrhoea, footpad dermatitis and digital ulcers) and had lower faecal oocyst counts than birds on the control diet. Our results demonstrate that carotenoid-rich corn maintains poultry health and increases the nutritional value of poultry products without the use of feed additives. PMID:25846059

  10. Kinetics of co-crystal formation with caffeine and citric acid via liquid-assisted grinding analyzed using the distinct element method.

    Science.gov (United States)

    Shimono, Keisuke; Kadota, Kazunori; Tozuka, Yuichi; Shimosaka, Atsuko; Shirakawa, Yoshiyuki; Hidaka, Jusuke

    2015-08-30

    The kinetics of co-crystal formation of caffeine (CF) with citric acid (CTA) was evaluated. Ball milling of CF and CTA in molar ratios of 4:1, 3:1, 2:1, 1:1, 1:2, 1:3, and 1:4 was performed by the liquid-assisted grinding (LAG) method. The samples were characterized by powder X-ray diffraction (PXRD), Fourier transform infrared spectroscopy (FT-IR) and differential scanning calorimetry (DSC). Two types of co-crystals (co-crystal-1, a 1:1 CF-CTA co-crystal; and co-crystal-2, a new co-crystal form) were obtained. The kinetic characteristics of this new co-crystal formation were assessed by calculating the ball impact energy and force using the distinct element method (DEM) simulations. The results indicated that co-crystal-2 creation occurred under a condition in which the ball impact force exceeded a certain threshold value. Moreover, the total ball impact energy was positively correlated with co-crystal formation, exhibiting a higher ball impact force than the threshold value. The kinetics of co-crystal-2 formation was almost consistent with the Jander equation. Consequently, co-crystal-2 formation could be explained according to a three-dimensional diffusion mechanism. PMID:25998562

  11. Chlorophyll and carotenoid pigments in solar saltern microbial mats

    Science.gov (United States)

    Villanueva, Joan; Grimalt, Joan O.; de Wit, Rutger; Keely, Brendan J.; Maxwell, James R.

    1994-11-01

    The distributions of carotenoids, chlorophylls, and their degradation products have been studied in two microbial mat systems developed in the calcite and calcite/gypsum evaporite domains of a solar saltern system. Phormidium valderianum and Microcoleus chthonoplastes are the dominant cyanobacterial species, respectively, and large amounts of Chloroflexus-like bacteria occur in the carbonate/gypsum mat. In both systems, the major pigments are chlorophyll a, zeaxanthin, β-carotene and myxoxanthophyll, which originate from these mat-building cyanobacteria. This common feature contrasts with differences in other pigments that are specific for each mat community. Thus, chlorophyll c and fucoxanthin, reflecting diatom inputs, are only found in the calcite mat, whereas the calcite/gypsum mat contains high concentrations of bacteriochlorophylls c produced by the multicellular green filamentous bacteria. In both cases, the depth concentration profiles (0-30 and 0-40 mm) show a relatively good preservation of the cyanobacterial carotenoids, zeaxanthin, β-carotene, myxoxanthophyll, and echinenone. This contrasts with the extensive biodegradation of cyanobacterial remains observed microscopically. Fucoxanthin in the calcite mat is also transformed at a faster rate than the cyanobacterial carotenoids. Chlorophyll a, the major pigment in both mats, exhibits different transformation pathways. In the calcite/gypsum mat, it is transformed via C-13 2 carbomethoxy defunctionalization prior to loss of the phytyl chain, leading to the formation of pyrophaeophytin a and, subsequently, pyrophaeophorbide a. On the other hand, the occurrence of the enzyme chlorophyllase, attributed to diatoms in the calcite mat, gives rise to extensive phytyl hydrolysis, with the formation of chlorophyllide a, pyrophaeophorbide a and, in minor proportion, phaeophorbide a. Studies of the sources of the photosynthetic pigments and of their transformation pathways in such simplified ecosystems provide a

  12. Radiation-induced formation, annealing and ordering of voids in crystals: Theory and experiment

    International Nuclear Information System (INIS)

    Void ordering has been observed in very different radiation environments ranging from metals to ionic crystals bombarded with energetic particles. The void ordering is often accompanied by a saturation of the void swelling with increasing irradiation dose, which makes an understanding of the underlying mechanisms to be both of scientific significance and of practical importance for nuclear engineering. We show that both phenomena can be explained by the original mechanism based on the anisotropic energy transfer provided by self-focusing discrete breathers or quodons (energetic, mobile, highly localized lattice solitons that propagate great distances along close-packed crystal directions). The interaction of quodons with voids can result in radiation-induced 'annealing' of selected voids, which results in the void ordering under special irradiation conditions. We observe experimentally radiation-induced void annealing by lowering the irradiation temperature of nickel and copper samples pre-irradiated to produce voids or gas bubbles. The bulk recombination of Frenkel pairs increases with decreasing temperature resulting in suppression of the production of freely migrating vacancies (the driving force of the void growth). On the other hand, the rate of radiation-induced vacancy emission from voids due to the void interaction with quodons remains essentially unchanged, which results in void dissolution. The experimental data on the void shrinkage and void lattice formation obtained for different metals and irradiating particles are explained by the present model assuming the quodon propagation length to be in the micron range, which is consistent with independent data on the irradiation-induced diffusion of interstitial ions in austenitic stainless steel.

  13. Composition of Carotenoids and Flavonoids in Narcissus Cultivars and their Relationship with Flower Color.

    Directory of Open Access Journals (Sweden)

    Xin Li

    Full Text Available Narcissus is widely used for cut flowers and potted plants, and is one of the most important commercial bulbous flowers in the floricultural industry. In this study, ten carotenoid and eighteen flavonoid compounds from the perianths and coronas of fifteen narcissus cultivars were measured by HPLC-APCI-MS/MS and UPLC-Q-TOF-MS/MS. Among these, six carotenoids, a total of seventeen flavonols and chlorogenic acid were identified in narcissus for the first time. A multivariate analysis was used to explore the relationship between flower color and pigment composition. We found that all-trans-violaxanthin and total carotenoid content were the main factors that affected flower color. These investigations could provide a global view of flower color formation and a theoretical basis for hybridization breeding in narcissus.

  14. Carotenoid evolution during short-storage period of durum wheat (Triticum turgidum conv. durum) and tritordeum (×Tritordeum Ascherson et Graebner) whole-grain flours.

    Science.gov (United States)

    Mellado-Ortega, Elena; Hornero-Méndez, Dámaso

    2016-02-01

    This study investigates the effect of storage temperature on carotenoid composition in durum wheat and tritordeum whole-grain flours. For both cereal genotypes, total carotenoid content significantly decreased during storage, following a temperature dependent first-order kinetic model. Individual and total carotenoid content decay were similar for durum wheat, with a maximum at 50 °C at the end of the storage period (94%). In contrast, the evolution of lutein ester fractions in tritordeum showed lower losses than for free lutein (∼ 50%), and consequently the total carotenoid content was less affected (83%). A decrease in the lutein monoesters fraction was observed, coinciding with an increase in the diesterified forms, especially for lutein dilinoleate. These data suggest an esterifying activity in flours different from the enzyme systems operating in vivo (xanthophyll acyl transferase). The formation of lutein diesters, with greater stability, explains the slower carotenoid degradation in tritordeum whole-grain flours. PMID:26304402

  15. An experimental apparatus for observing deterministic structure formation in plate-on-pedestal ice crystal growth

    OpenAIRE

    Libbrecht, Kenneth G.

    2015-01-01

    We describe an experimental apparatus for making detailed morphological observations of the growth of isolated plate-like ice crystals from water vapor. Each crystal develops a plate-on-pedestal (POP) geometry, in which a large, thin, plate-like crystal grows out from the top edge of an initially prismatic seed crystal resting on a substrate. With the POP geometry, the substrate is not in contact with the growing plate (except at its center), so substrate interactions do not adversely affect ...

  16. Crystal structures and phase formation thermodynamics of iron-gold nanoclusters

    Science.gov (United States)

    Mukherjee, Pinaki

    Alloy nanoparticles are being increasingly used in wide variety of applications (catalysis, contrast enhancement in magnetic resonance imaging, etc.). Knowledge of crystal structure and phase formation of the alloy nanoparticles is critical for these applications. Anomalous thermodynamic behavior and unusual phase formation have been reported for nanoparticles with size below 10 nm. In the present work, inert gas condensation (IGC) has been used to produce Au-Fe nanoclusters of varied compositions with a mean size between 5-10 nm. Here, the nanoclusters below 10 nm display complete solubility between Fe and Au in Fex Au1-x (0.3 0.65 and fcc for x self-interstitials. The as-deposited clusters were ferromagnetic at room temperature. Heat treatment at 600°C for 15 minutes followed by furnace cooling resulted in the size-dependent transformation of the clusters into additional, non-equilibrium structures that depended on cluster composition, while larger clusters followed bulk behavior. At about 65 atom % Fe, clusters transformed to a well-ordered, single fcc phase with a lattice parameter of 0.363 nm, whereas the phase diagram predicted two-phase equilibrium. The stabilization of a single fcc phase was explained by a thermodynamic analysis. This analysis suggests that the single phase stability in the Fe-Au nanoparticles arises from the fact that the introduction of a phase boundary is energetically opposed. Heat treatment of as-deposited particles results in L12 and L1 0ordered structures near 1:3, 3:1 and 1:1 (Fe:Au) stoichiometries respectively. Magnetically, these nanoparticles display strong ferromagnetic behavior for Fe-rich solid solutions and for the 3:1 L12 structure, and weak ferromagnetic behavior, possibly due to a combination of antiferromagnetic core and uncompensated spins at the surface for other compositions.

  17. Carotenoids: potential allies of cardiovascular health?

    Directory of Open Access Journals (Sweden)

    Maria Alessandra Gammone

    2015-02-01

    Full Text Available Carotenoids are a class of natural, fat-soluble pigments found principally in plants. They have potential antioxidant biological properties because of their chemical structure and interaction with biological membranes. Epidemiologic studies supported the hypothesis that antioxidants could be used as an inexpensive means of both primary and secondary cardiovascular disease (CVD prevention. In fact, the oxidation of low-density lipoproteins (LDL in the vessels plays a key role in the development of atherosclerotic lesions. The resistance of LDL to oxidation is increased by high dietary antioxidant intake, so that carotenoids, as part of food patterns such as the Mediterranean diet, may have beneficial effects on cardiovascular health too. Further properties of carotenoids leading to a potential reduction of cardiovascular risk are represented by lowering of blood pressure, reduction of pro-inflammatory cytokines and markers of inflammation (such as C-reactive protein, and improvement of insulin sensitivity in muscle, liver, and adipose tissues. In addition, recent nutrigenomics studies have focused on the exceptional ability of carotenoids in modulating the expression of specific genes involved in cell metabolism. The aim of this review is to focus attention to this effect of some carotenoids to prevent CVD.

  18. Supercritical Fluid Extraction of Palm Carotenoids

    Directory of Open Access Journals (Sweden)

    Puah C. Wei

    2005-01-01

    Full Text Available The extraction of carotenoids from crude palm oil was carried out in a dynamic (flow- through supercritical fluid extraction system. The carotenoids obtained were quantified using off-line UV-visible spectrophotometry. The effects of operating pressure and temperature, flow rate of the supercritical carbon dioxide (SC-CO2, sample size of feed used on the solubility of palm carotenoids were investigated. The results showed that the extraction of carotenoids was governed by its solubility in the SC-CO2 and can be enhanced by increasing pressure at a constant temperature or decreasing temperature at a constant pressure. Increasing the flow rate and decreasing the sample size can reduce the extraction time but do not enhance the solubility. Palm carotenoids have very low solubility in SC-CO2 in the range of 1.31 x 10-4 g kg-1 to 1.58 x 10-3 g kg-1 for the conditions investigated in this study. The experimental data obtained were compared with those published by other workers and correlated by a density-based equation as proposed by Chrastil.

  19. Detergent-Mediated Formation of β-Hematin: Heme Crystallization Promoted by Detergents Implicates Nanostructure Formation for Use as a Biological Mimic

    OpenAIRE

    Sandlin, Rebecca D.; Kim Y. Fong; Stiebler, Renata; Gulka, Christopher P.; Nesbitt, Jenny E.; Oliveira, Matheus P.; Oliveira, Marcus F.; David W. Wright

    2016-01-01

    Hemozoin is a unique biomineral that results from the sequestration of toxic free heme liberated as a consequence of hemoglobin degradation in the malaria parasite. Synthetic neutral lipid droplets (SNLDs) and phospholipids were previously shown to support the rapid formation of β-hematin, abiological hemozoin, under physiologically relevant pH and temperature, though the mechanism by which heme crystallization occurs remains unclear. Detergents are particularly interesting as a template beca...

  20. Cystone, a well-known herbal formulation, inhibits struvite crystal growth formation in single diffusion gel growth technique

    Directory of Open Access Journals (Sweden)

    Pralhad S. Patki

    2013-02-01

    Full Text Available Objective: The present study was aimed to evaluate the beneficial effect of Cystone® against struvite crystal growth in in vitro conditions. Methods: Various concentrations of Cystone® was prepared in 1 M magnesium acetate solution and evaluated for crystal growth inhibition assay by a well-known method called single diffusion gel growth technique in vitro. Results: Cystone®, a well-known polyherbal formulation, at 0.5, 1 and 2% concentrations showed significant and dose-dependent inhibition of struvite crystal growth formation in in vitro by reducing number, total mass and total volume of the struvite crystals formed and also caused fragmentation of grown struvite crystals in the gel matrix. Conclusion: The results of the present study indicate, Cystone® significantly retards the formation of struvite stones and also brings about its fragmentation. This could be one of the probable mechanisms behind the beneficial effect offered by Cystone® in the clinical management of urolithiasis and urinary tract infections. [J Exp Integr Med 2013; 3(1: 51-55

  1. On the formation of shocks of electromagnetic plane waves in non-linear crystals

    Science.gov (United States)

    Christodoulou, Demetrios; Perez, Daniel Raoul

    2016-08-01

    An influential result of F. John states that no genuinely non-linear strictly hyperbolic quasi-linear first order system of partial differential equations in two variables has a global C2-solution for small enough initial data. Inspired by recent work of D. Christodoulou, we revisit John's original proof and extract a more precise description of the behaviour of solutions at the time of shock. We show that John's singular first order quantity, when expressed in characteristic coordinates, remains bounded until the final time, which is then characterised by an inverse density of characteristics tending to zero in one point. Moreover, we study the derivatives of second order, showing again their boundedness when expressed in appropriate coordinates. We also recover John's upper bound for the time of shock formation and complement it with a lower bound. Finally, we apply these results to electromagnetic plane waves in a crystal with no magnetic properties and cubic electric non-linearity in the energy density, assuming no dispersion.

  2. On the formation of shocks of electromagnetic plane waves in non-linear crystals

    CERN Document Server

    Christodoulou, Demetrios

    2015-01-01

    An influential result of F. John states that no genuinely non-linear strictly hyperbolic quasi-linear first order system of partial differential equations in two variables has a global $C^2$-solution for small enough initial data. Inspired by recent work of D. Christodoulou, we revisit John's original proof and extract a more precise description of the behaviour of solutions at the time of shock. We show that John's singular first order quantity, when expressed in characteristic coordinates, remains bounded until the final time, which is then characterised by an inverse density of characteristics tending to zero in one point. Moreover, we study the derivatives of second order, showing again their boundedness when expressed in appropriate coordinates. We also recover John's upper bound for the time of shock formation and complement it with a lower bound. Finally, we apply these results to electromagnetic plane waves in a crystal with no magnetic properties and cubic electric non-linearity in the energy density...

  3. Flow-Induced Crystallization of Collagen: A Potentially Critical Mechanism in Early Tissue Formation.

    Science.gov (United States)

    Paten, Jeffrey A; Siadat, Seyed Mohammad; Susilo, Monica E; Ismail, Ebraheim N; Stoner, Jayson L; Rothstein, Jonathan P; Ruberti, Jeffrey W

    2016-05-24

    The type I collagen monomer is one of nature's most exquisite and prevalent structural tools. Its 300 nm triple-helical motifs assemble into tough extracellular fibers that transition seamlessly across tissue boundaries and exceed cell dimensions by up to 4 orders of magnitude. In spite of extensive investigation, no existing model satisfactorily explains how such continuous structures are generated and grown precisely where they are needed (aligned in the path of force) by discrete, microscale cells using materials with nanoscale dimensions. We present a simple fiber drawing experiment, which demonstrates that slightly concentrated type I collagen monomers can be "flow-crystallized" to form highly oriented, continuous, hierarchical fibers at cell-achievable strain rates (fibers. While mechanical tension has been shown to be a critical factor driving collagen fibril formation during tissue morphogenesis in developing animals, the precise role of force in the process of building tissue is not well understood. Our data directly couple mechanical tension, specifically the extensional strain rate, to collagen fibril assembly. We further derive a "growth equation" which predicts that application of extensional strains, either globally by developing muscles or locally by fibroblasts, can rapidly drive the fusion of already formed short fibrils to produce long-range, continuous fibers. The results provide a pathway to scalable connective tissue manufacturing and support a mechano-biological model of collagen fibril deposition and growth in vivo. PMID:27070851

  4. Effects of added silica nanoparticles on the nematic liquid crystal phase formation in beidellite suspensions.

    Science.gov (United States)

    Landman, Jasper; Paineau, Erwan; Davidson, Patrick; Bihannic, Isabelle; Michot, Laurent J; Philippe, Adrian-Marie; Petukhov, Andrei V; Lekkerkerker, Henk N W

    2014-05-01

    In this article, we present a study of the liquid crystal phase behavior of mixed suspensions of the natural smectite clay mineral beidellite and nonadsorbing colloidal silica particles. While virtually all smectite clays dispersed in water form gels at very low concentrations, beidellite displays a first order isotropic-nematic phase transition before gel formation (J. Phys. Chem. B, 2009, 113, 15858-15869). The addition of silica nanospheres shifts the concentrations of the coexisting isotropic and nematic phases to slightly higher values while at the same time markedly accelerating the phase separation process. Furthermore, beidellite suspensions at volume fractions above the isotropic-nematic phase separation, trapped in a kinetically arrested gel state, liquefy on the addition of silica nanospheres and proceed to isotropic-nematic phase separation. Using small-angle X-ray scattering (SAXS), we probe the structural changes caused by the addition of the silica nanospheres, and we relate the modification of the phase transition kinetics to the change of the rheological properties. PMID:24758198

  5. Peptide Induced Crystallization of Calcium Carbonate on Wrinkle Patterned Substrate: Implications for Chitin Formation in Molluscs

    Directory of Open Access Journals (Sweden)

    Ingrid M. Weiss

    2013-06-01

    Full Text Available We here present the nucleation and growth of calcium carbonate under the influence of synthetic peptides on topographically patterned poly(dimethylsiloxane (PDMS substrates, which have a controlled density of defects between the wrinkles. Experiments with two lysine-rich peptides derived from the extracellular conserved domain E22 of the mollusc chitin synthase Ar-CS1, AKKKKKAS (AS8 and EEKKKKKES (ES9 on these substrates showed their influence on the calcium carbonate morphology. A transition from polycrystalline composites to single crystalline phases was achieved with the peptide AS8 by changing the pH of the buffer solution. We analyzed three different pH values as previous experiments showed that E22 interacts with aragonite biominerals more strongly at pH 7.75 than at pH 9.0. At any given pH, crystals appeared in characteristic morphologies only on wrinkled substrates, and did not occur on the flat, wrinkle-free PDMS substrate. These results suggest that these wrinkled substrates could be useful for controlling the morphologies of other mineral/peptide and mineral/protein composites. In nature, these templates are formed enzymatically by glycosyltransferases containing pH-sensitive epitopes, similar to the peptides investigated here. Our in vitro test systems may be useful to gain understanding of the formation of distinct 3D morphologies in mollusc shells in response to local pH shifts during the mineralization of organic templates.

  6. Mesoscale flux-closure domain formation in single-crystal BaTiO3.

    Science.gov (United States)

    McQuaid, R G P; McGilly, L J; Sharma, P; Gruverman, A; Gregg, J M

    2011-01-01

    Over 60 years ago, Charles Kittel predicted that quadrant domains should spontaneously form in small ferromagnetic platelets. He expected that the direction of magnetization within each quadrant should lie parallel to the platelet surface, minimizing demagnetizing fields,and that magnetic moments should be configured into an overall closed loop, or flux-closure arrangement. Although now a ubiquitous observation in ferromagnets, obvious flux-closure patterns have been somewhat elusive in ferroelectric materials. This is despite the analogous behaviour between these two ferroic subgroups and the recent prediction of dipole closure states by atomistic simulations research. Here we show Piezoresponse Force Microscopy images of mesoscopic dipole closure patterns in free-standing, single-crystal lamellae of BaTiO(3). Formation of these patterns is a dynamical process resulting from system relaxation after the BaTiO(3) has been poled with a uniform electric field. The flux-closure states are composed of shape conserving 90° stripe domains which minimize disclination stresses. PMID:21792183

  7. Lack of Evidence for Prenucleation Aggregate Formation in Lysozyme Crystal Growth Solutions

    Science.gov (United States)

    Muschol, Martin; Rosenberger, Franz

    1996-01-01

    There have been numerous claims of large concentrations of prenucleation aggregates in supersaturated as well as undersaturated lysozyme solutions at high salt concentrations. The presence of these aggregates was derived from measurements of the light or neutron scattering intensity, ultracentrifugation and dialysis behavior, as well as over-simplified crystal growth kinetics considerations. In all these interpretations it has been assumed that lysozyme solutions are either ideal or that protein interactions are independent of salt concentration. Contrary to these presumptions, our static and dynamic light scattering experiments provide evidence that lysozyme forms highly non-ideal, strongly interacting solutions. At low salt concentrations, the scattering intensities fall well below the values expected for an ideal, monomeric solution at the same protein concentration, while diffusivities increase with increasing protein concentration. Upon increase in salt concentration, these trends are eventually reversed. This enhancement in scattering intensity and decrease in diffusivity was widely interpreted as sign of aggregate formation. Yet, a quantitative interpretation of the scattering behavior over the whole salt concentration range can only be given in terms of a transition from net repulsion to net attraction between lysozyme monomers. Increased salt screening of the electrostatic repulsion among the protein macro-ions, together with attractive protein interactions, such as van der Waals, hydrophobic and hydration forces, provide an unambiguous mechanism for the observed transition and a more physical interpretation of the various observations.

  8. Influence of PEG-12 Dimethicone addition on stability and formation of emulsions containing liquid crystal.

    Science.gov (United States)

    Andrade, F F; Santos, O D H; Oliveira, W P; Rocha-Filho, P A

    2007-06-01

    Oil/water emulsions, containing liquid crystals, were developed employing Andiroba oil, PEG-12 Dimethicone and Crodafos CES. It was evaluated the influence of silicone surfactants on the emulsions stability and on the formation of liquid crystalline phases and therefore, physicochemical characteristics, such as rheology and zeta potential, were evaluated. Emulsions were prepared by the emulsions phase inversion method. All the formulations presented lamellar liquid crystalline phases. The PEG-12 Dimethicone addition did not change microscopically the liquid crystalline phases. The emulsions containing silicone demonstrated lower viscosity than those without the additive. This is an important feature, as the silicone did not change the rheological profile; however, the addition of silicone still can be used as a viscosity controller. The formulations had their viscosity increased 15 and 150 days after their preparation. This characteristic shows that the emulsions have their organization increased along the storing time. In the analysis of zeta potential, we could verify that all formulations presented negative values between -39.7 and -70.0 mV. Within this range of values, the emulsion physical stability is high (Fig. 10). It was concluded that the addition of PEG-12 Dimethicone kept the liquid crystalline phase of the emulsion obtained with Crodafos CES, influencing in a positive way in the system stability. PMID:18489351

  9. Dietary carotenoids predict plumage coloration in wild house finches.

    OpenAIRE

    Hill, Geoffrey E.; Inouye, Caron Y; Montgomerie, Robert

    2002-01-01

    Carotenoid pigments are a widespread source of ornamental coloration in vertebrates and expression of carotenoid-based colour displays has been shown to serve as an important criterion in female mate choice in birds and fishes. Unlike other integumentary pigments, carotenoids cannot be synthesized; they must be ingested. Carotenoid-based coloration is condition-dependent and has been shown to be affected by both parasites and nutritional condition. A controversial hypothesis is that the expre...

  10. Molecular Characterization of Carotenoid Biosynthetic Genes and Carotenoid Accumulation in Lycium chinense

    Directory of Open Access Journals (Sweden)

    Shicheng Zhao

    2014-07-01

    Full Text Available Lycium chinense is a shrub that has health benefits and is used as a source of medicines in Asia. In this study, a full-length cDNA clone encoding β-ring carotene hydroxylase (LcCHXB and partial-length cDNA clones encoding phytoene synthase (LcPSY, phytoene desaturase (LcPDS, ξ-carotene desaturase (LcZDS, lycopene β-cyclase (LcLCYB, lycopene ε-cyclase (LcLCYE, ε-ring carotene hydroxylase (LcCHXE, zeaxanthin epoxidase (LcZEP, carotenoid cleavage dioxygenase (LcCCD1, and 9-cis epoxycarotenoid dioxygenase (LcNCED were identified in L. chinense. The transcripts were constitutively expressed at high levels in leaves, flowers and red fruits, where the carotenoids are mostly distributed. In contrast, most of the carotenoid biosynthetic genes were weakly expressed in the roots and stems, which contained only small amounts of carotenoids. The level of LcLCYE transcripts was very high in leaves and correlated with the abundance of lutein in this plant tissue. During maturation, the levels of lutein and zeaxanthin in L. chinense fruits dramatically increased, concomitant with a rise in the level of β-cryptoxanthin. LcPSY, LcPDS, LcZDS, LcLCYB, and LcCHXE were highly expressed in red fruits, leading to their substantially higher total carotenoid content compared to that in green fruits. Total carotenoid content was high in both the leaves and red fruits of L. chinense. Our findings on the biosynthesis of carotenoids in L. chinense provide insights into the molecular mechanisms involved in carotenoid biosynthesis and may facilitate the optimization of carotenoid production in L. chinense.

  11. Carotenoid content of 50 watermelon cultivars.

    Science.gov (United States)

    Perkins-Veazie, Penelope; Collins, Julie K; Davis, Angela R; Roberts, Warren

    2006-04-01

    The lycopene content of 50 commercial cultivars of seeded and seedless red-fleshed watermelons was determined. Scanning colorimetric and spectrophotometric assays of total lycopene were used to separate watermelon cultivars into low (90 mg/kg fw). Cultivars varied greatly in lycopene content, ranging from 33 to 100 mg/kg. Most of the seeded hybrid cultivars had average lycopene contents. Sixteen of the 33 seedless types had lycopene contents in the high and very high ranges. All-trans-lycopene was the predominant carotenoid (84-97%) in all watermelon cultivars measured by high-performance liquid chromatography, but the germplasm differed in the relative amounts of cis-lycopene, beta-carotene, and phytofluene. Red-fleshed watermelon genotypes vary extensively in carotenoid content and offer opportunities for developing watermelons with specifically enhanced carotenoids. PMID:16569049

  12. Photodegradation of carotenoids in human subjects

    International Nuclear Information System (INIS)

    Photodegradation of vitamins in vitro is responsible for large losses of these nutrients in foods, beverages, and semisynthetic liquid formula diets. In vivo photodegradation of vitamins has been reported for riboflavin in jaundiced infants exposed to blue light and for folate in patients with chronic psoriasis given photochemotherapy. Two recent studies of normal subjects have also shown that photodegradation of carotenoids in plasma occurs with cumulative exposure of the skin to an artificial light source having maximal spectral emission in the UVA range. Females showed a larger effect of the UV light on their plasma carotenoid levels than males. These observations have identified a need for further investigation of the role of sunlight exposure as a determinant of plasma carotenoid levels and vitamin A status in human subjects

  13. Dietary intake of carotenoids and risk of type 2 diabetes

    NARCIS (Netherlands)

    Sluijs, I.; Cadier, E.; Beulens, J. W J; van der A, D. L.; Spijkerman, A. M W; van der Schouw, Y. T.

    2015-01-01

    Background and aims: Carotenoids may reduce diabetes risk, due to their antioxidant properties. However, the association between dietary carotenoids intake and type 2 diabetes risk is still unclear. Therefore, the objective of this study was to examine whether higher dietary carotenoid intakes assoc

  14. The fate of carotenoids in sediments: An overview

    NARCIS (Netherlands)

    Sinninghe Damsté, J.S.; Koopmans, M.P.

    1997-01-01

    Despite carotenoids being abundant natural products, there are only scattered literature reports of carotenoid derivatives (mainly in the form of their 'perhydro' derivatives) in ancient sediments and petroleum. This was thought to be due to the sensitivity of carotenoids toward oxygen and their pre

  15. Dehydrolutein: a metabolically derived carotenoid never observed in raptors

    Institute of Scientific and Technical Information of China (English)

    David COSTANTINI; Vittorio BERTACCHE; Barbara PASTURA; Anthony TURK

    2009-01-01

    @@ Carotenoids are fat-soluble pigments synthesised by photosynthetic organisms (Brush, 1990). Conversely, animals are incapable of synthesizing carotenoids de novo, and they must obtain them through their diet. However, some animal species are able to make some alterations to the basic chemical structure, converting ingested carotenoids into more oxidized and differently coloured forms (Schiedt, 1998).

  16. Dietary factors that affect the bioavailability of carotenoids

    NARCIS (Netherlands)

    Hof, van het K.H.; West, C.E.; Weststrate, J.A.; Hautvast, J.G.A.J.

    2000-01-01

    Carotenoids are thought to contribute to the beneficial effects of increased vegetable consumption. Various dietary factors have an effect on the bioavailability of carotenoids. The type of food matrix in which carotenoids are located is a major factor. The bioavailability of ß-carotene from vegetab

  17. Regulation of carotenoid accumulation and the expression of carotenoid metabolic genes in citrus juice sacs in vitro

    OpenAIRE

    Zhang, Lancui; Ma, Gang; Kato, Masaya; Yamawaki, Kazuki; Takagi, Toshihiko; Kiriiwa, Yoshikazu; Ikoma, Yoshinori; Matsumoto, Hikaru; Yoshioka, Terutaka; Nesumi, Hirohisa

    2011-01-01

    In the present study, to investigate the mechanisms regulating carotenoid accumulation in citrus, a culture system was set up in vitro with juice sacs of three citrus varieties, Satsuma mandarin (Citrus unshiu Marc.), Valencia orange (Citrus sinensis Osbeck), and Lisbon lemon (Citrus limon Burm.f.). The juice sacs of all the three varieties enlarged gradually with carotenoid accumulation. The changing patterns of carotenoid content and the expression of carotenoid metabolic genes in juice sac...

  18. Dietary Carotenoids Regulate Astaxanthin Content of Copepods and Modulate Their Susceptibility to UV Light and Copper Toxicity

    Directory of Open Access Journals (Sweden)

    Kevin R. Carman

    2012-04-01

    Full Text Available High irradiation and the presence of xenobiotics favor the formation of reactive oxygen species in marine environments. Organisms have developed antioxidant defenses, including the accumulation of carotenoids that must be obtained from the diet. Astaxanthin is the main carotenoid in marine crustaceans where, among other functions, it scavenges free radicals thus protecting cell compounds against oxidation. Four diets with different carotenoid composition were used to culture the meiobenthic copepod Amphiascoides atopus to assess how its astaxanthin content modulates the response to prooxidant stressors. A. atopus had the highest astaxanthin content when the carotenoid was supplied as astaxanthin esters (i.e., Haematococcus meal. Exposure to short wavelength UV light elicited a 77% to 92% decrease of the astaxanthin content of the copepod depending on the culture diet. The LC50 values of A. atopus exposed to copper were directly related to the initial astaxanthin content. The accumulation of carotenoids may ascribe competitive advantages to certain species in areas subjected to pollution events by attenuating the detrimental effects of metals on survival, and possibly development and fecundity. Conversely, the loss of certain dietary items rich in carotenoids may be responsible for the amplification of the effects of metal exposure in consumers.

  19. Relativistic electron Wigner crystal formation in a cavity for electron acceleration

    CERN Document Server

    Thomas, Johannes; Pukhov, Alexander

    2014-01-01

    It is known that a gas of electrons in a uniform neutralizing background can crystallize and form a lattice if the electron density is less than a critical value. This crystallization may have two- or three-dimensional structure. Since the wake field potential in the highly-nonlinear-broken-wave regime (bubble regime) has the form of a cavity where the background electrons are evacuated from and only the positively charged ions remain, it is suited for crystallization of trapped and accelerated electron bunch. However, in this case, the crystal is moving relativistically and shows new three-dimensional structures that we call relativistic Wigner crystals. We analyze these structures using a relativistic Hamiltonian approach. We also check for stability and phase transitions of the relativistic Wigner crystals.

  20. Crystal structure and solution species of Ce(III) and Ce(IV) formates: from mononuclear to hexanuclear complexes.

    Science.gov (United States)

    Hennig, Christoph; Ikeda-Ohno, Atsushi; Kraus, Werner; Weiss, Stephan; Pattison, Philip; Emerich, Hermann; Abdala, Paula M; Scheinost, Andreas C

    2013-10-21

    Cerium(III) and cerium(IV) both form formate complexes. However, their species in aqueous solution and the solid-state structures are surprisingly different. The species in aqueous solutions were investigated with Ce K-edge EXAFS spectroscopy. Ce(III) formate shows only mononuclear complexes, which is in agreement with the predicted mononuclear species of Ce(HCOO)(2+) and Ce(HCOO)2(+). In contrast, Ce(IV) formate forms in aqueous solution a stable hexanuclear complex of [Ce6(μ3-O)4(μ3-OH)4(HCOO)x(NO3)y](12-x-y). The structural differences reflect the different influence of hydrolysis, which is weak for Ce(III) and strong for Ce(IV). Hydrolysis of Ce(IV) ions causes initial polymerization while complexation through HCOO(-) results in 12 chelate rings stabilizing the hexanuclear Ce(IV) complex. Crystals were grown from the above-mentioned solutions. Two crystal structures of Ce(IV) formate were determined. Both form a hexanuclear complex with a [Ce6(μ3-O)4(μ3-OH)4](12+) core in aqueous HNO3/HCOOH solution. The pH titration with NaOH resulted in a structure with the composition [Ce6(μ3-O)4(μ3-OH)4(HCOO)10(NO3)2(H2O)3]·(H2O)9.5, while the pH adjustment with NH3 resulted in [Ce6(μ3-O)4(μ3-OH)4(HCOO)10(NO3)4]·(NO3)3(NH4)5(H2O)5. Furthermore, the crystal structure of Ce(III) formate, Ce(HCOO)3, was determined. The coordination polyhedron is a tricapped trigonal prism which is formed exclusively by nine HCOO(-) ligands. The hexanuclear Ce(IV) formate species from aqueous solution is widely preserved in the crystal structure, whereas the mononuclear solution species of Ce(III) formate undergoes a polymerization during the crystallization process. PMID:24090406

  1. Environmental effects shape the maternal transfer of carotenoids and vitamin E to the yolk

    Directory of Open Access Journals (Sweden)

    Müller Wendt

    2012-08-01

    Full Text Available Abstract Introduction Maternal effects occur when the phenotype of the offspring is influenced by the phenotype of the mother, which in turn depends on her heritable state as well as on influences from the current and past environmental conditions. All of these pathways may, therefore, form significant sources of variation in maternal effects. Here, we focused on the maternal transfer of carotenoids and vitamin E to the egg yolk, using canaries as a model species. Maternal yolk carotenoids and vitamin E are known to generate significant phenotypic variation in offspring, representing examples of maternal effects. We studied the intra-individual consistency in deposition patterns across two years and the mother-daughter resemblance across two generations in order to estimate the level of heritable variation. The effects of the current environmental conditions were studied via a food supplementation experiment, while the consequences of past environmental conditions were estimated on the basis of the early growth trajectories. Results There was a significant effect of the current environmental conditions on the yolk carotenoid and vitamin E deposition, but this effect varied between antioxidant components. The deposition of yolk carotenoids and vitamin E were linked to the process of yolk formation. Past environmental conditions did not contribute to the variation in yolk carotenoid and vitamin E levels nor did we find significant heritable variation. Conclusions The transfer of carotenoids or vitamin E may be an example where current environmental variation is largely passed from the mother to the offspring, despite the numerous intermediate physiological steps that are involved. Differences in the effect of the environmental conditions as experienced by the mother during laying may be due to differences in availability as well as physiological processes such as competitive exclusion or selective absorption.

  2. Crystallization and cooling conditions for the diogenite formation in the turbulent magma ocean of the asteroid 4 Vesta

    CERN Document Server

    Kawabata, Yusuke

    2016-01-01

    The asteroid 4 Vesta has been completely differentiated to core and mantle despite its small size, of which surface materials are howardite-eucrite-diogenite (HED) meteorites that we know the detailed petrology, and therefore, is a good target for understanding differentiation of terrestrial planets. A new differentiation model for crust formation was developed by taking magma ocean fluid dynamics, chemical equilibrium, presence of $^{26}$Al, and cooling into consideration with special care to crystal separation. The role of crystal size, thickness of the conductive lid, and fO2 are evaluated as parameters. The results show that large crystals (1cm) settle and form a km-thick cumulate layer of orthopyroxene with Mg# of 0.70-0.90 in ~20 thousand years, which almost agrees with the Mg# of diogenites, whereas thinner layers are formed if the grain size is smaller.

  3. Formation of Crystal Structure of Zirconium Titanate ZrTiO4 Powders Prepared by Sol-Gel Method

    Science.gov (United States)

    Oanh, Le Mai; Do, Danh Bich; Hung, Nguyen Manh; Thang, Dao Viet; Phuong, Doan Thuy; Ha, Dang Thu; Van Minh, Nguyen

    2016-05-01

    The crystal formation process of ZrTiO4 prepared by sol-gel method has been investigated using thermogravimetric analysis, differential thermal analysis, x-ray diffraction (XRD) analysis, scanning electron microscopy, Raman scattering, ultraviolet-visible (UV-Vis) absorption spectroscopy, and photoluminescence spectroscopy. Thermal analysis results and XRD patterns show that ZrTiO4 crystallizes in orthorhombic phase at 700°C with onset point at about 580°C. However, ZrTiO4 crystal exhibits a disordered structure according to Raman, UV-Vis, and photoluminescence spectroscopy up to calcination temperature of 1200°C. This indicates that, in the heat-treatment process, ZrTiO4 underwent three stages of oxide system self-organization: (1) short-range (structure (>1200°C).

  4. Theory and simulation of ion Coulomb crystal formation in a Penning trap

    Science.gov (United States)

    Asprusten, Martin; Worthington, Simon; Thompson, Richard C.

    2014-01-01

    Ion Coulomb crystals (ICCs) are formed by laser-cooled ions in both radio-frequency and Penning traps. In radio-frequency traps, the crystals are generally stationary. In Penning traps, ICCs always rotate. The frequency of rotation is often set by an applied rotating wall drive that forces the crystal to rotate at the same frequency as the drive. In the absence of any applied rotating or oscillating fields, ICCs in a Penning trap can be in stable equilibrium with a range of rotation frequencies. The density and shape of the crystal adjust with the rotation frequency to ensure that equilibrium is reached. Here, we show that the parameters of the radial laser-cooling beam determine the rotation frequency of a small crystal in a Penning trap when no driving fields are present. We demonstrate, using an approximate theoretical treatment and realistic simulations, that the crystal rotation frequency is independent of the number of ions and the trap parameters, so long as the crystal radius remains smaller than the cooling laser beam waist. As the rotation frequency increases, the crystal eventually becomes a linear string, at which point it is no longer able to adjust its density. Instead, a small amplitude vibration in the zigzag mode of oscillation manifests itself as a rotation of the crystal at a fixed frequency that depends only on the applied trap potential.

  5. ZEAXANTHIN EPOXIDASE Activity Potentiates Carotenoid Degradation in Maturing Seed.

    Science.gov (United States)

    Gonzalez-Jorge, Sabrina; Mehrshahi, Payam; Magallanes-Lundback, Maria; Lipka, Alexander E; Angelovici, Ruthie; Gore, Michael A; DellaPenna, Dean

    2016-07-01

    Elucidation of the carotenoid biosynthetic pathway has enabled altering the composition and content of carotenoids in various plants, but to achieve desired nutritional impacts, the genetic components regulating carotenoid homeostasis in seed, the plant organ consumed in greatest abundance, must be elucidated. We used a combination of linkage mapping, genome-wide association studies (GWAS), and pathway-level analysis to identify nine loci that impact the natural variation of seed carotenoids in Arabidopsis (Arabidopsis thaliana). ZEAXANTHIN EPOXIDASE (ZEP) was the major contributor to carotenoid composition, with mutants lacking ZEP activity showing a remarkable 6-fold increase in total seed carotenoids relative to the wild type. Natural variation in ZEP gene expression during seed development was identified as the underlying mechanism for fine-tuning carotenoid composition, stability, and ultimately content in Arabidopsis seed. We previously showed that two CAROTENOID CLEAVAGE DIOXYGENASE enzymes, CCD1 and CCD4, are the primary mediators of seed carotenoid degradation, and here we demonstrate that ZEP acts as an upstream control point of carotenoid homeostasis, with ZEP-mediated epoxidation targeting carotenoids for degradation by CCD enzymes. Finally, four of the nine loci/enzymatic activities identified as underlying natural variation in Arabidopsis seed carotenoids also were identified in a recent GWAS of maize (Zea mays) kernel carotenoid variation. This first comparison of the natural variation in seed carotenoids in monocots and dicots suggests a surprising overlap in the genetic architecture of these traits between the two lineages and provides a list of likely candidates to target for selecting seed carotenoid variation in other species. PMID:27208224

  6. Carotenoid-protein interaction alters the S1 energy of hydroxyechinenone in the Orange Carotenoid Protein

    Czech Academy of Sciences Publication Activity Database

    Polívka, Tomáš; Chábera, P.; Kerfeld, C.A.

    2013-01-01

    Roč. 1827, č. 3 (2013), s. 248-254. ISSN 0005-2728 Institutional support: RVO:60077344 Keywords : orange-carotenoid protein * excited states * photoprotection Subject RIV: BO - Biophysics Impact factor: 4.829, year: 2013

  7. Formation of Cholesterol Bilayer Domains Precedes Formation of Cholesterol Crystals in Cholesterol/Dimyristoylphosphatidylcholine Membranes: EPR and DSC Studies

    OpenAIRE

    Mainali, Laxman; Raguz, Marija; Subczynski, Witold K.

    2013-01-01

    Saturation-recovery EPR along with DSC were used to determine the cholesterol content at which pure cholesterol bilayer domains (CBDs) and cholesterol crystals begin to form in dimyristoylphosphatidylcholine (DMPC) membranes. To preserve compositional homogeneity throughout the membrane suspension, lipid multilamellar dispersions were prepared using a rapid solvent exchange method. The cholesterol content increased from 0 to 75 mol%. With spin-labeled cholesterol analogs it was shown that the...

  8. The carotenoid-continuum: carotenoid-based plumage ranges from conspicuous to cryptic and back again

    Directory of Open Access Journals (Sweden)

    Roberts Mark L

    2010-05-01

    Full Text Available Abstract Background Carotenoids are frequently used by birds to colour their plumage with green, yellow, orange or red hues, and carotenoid-based colours are considered honest signals of quality, although they may have other functions, such as crypsis. It is usually assumed that red through yellow colours have a signalling function while green is cryptic. Here we challenge this notion using the yellow and green colouration of blue tits (Cyanistes caeruleus, great tits (Parus major and greenfinches (Carduelis chloris as a model. Results The relationship between colouration (chroma, computed using visual sensitivities of conspecifics and detectability (contrast against natural backgrounds as perceived by conspecifics and avian predators followed a similar curvilinear pattern for yellow and green plumage with minimum detectability at intermediate levels of carotenoid deposition. Thus, for yellow and green plumage, colours at or close to the point of minimum detectability may aid in crypsis. This may be the case for blue and great tit green and yellow plumage, and greenfinch green plumage, all of which had comparably low levels of detectability, while greenfinch yellow plumage was more chromatic and detectable. As yellow and green blue tit colouration are strongly affected by carotenoid availability during moult, variation in pigment availability between habitats may affect the degree of background-matching or the costliness of producing cryptic plumage. Conclusions Increasing carotenoid-deposition in the integument does not always lead to more conspicuous colours. In some cases, such as in blue or great tits, carotenoid deposition may be selected through enhanced background-matching, which in turn suggests that producing cryptic plumage may entail costs. We stress however, that our data do not rule out a signalling function of carotenoid-based plumage in tits. Rather, it shows that alternative functions are plausible and that assuming a signalling

  9. Formation of crystal-like structures and branched networks from nonionic spherical micelles

    Science.gov (United States)

    Cardiel, Joshua J.; Furusho, Hirotoshi; Skoglund, Ulf; Shen, Amy Q.

    2015-12-01

    Crystal-like structures at nano and micron scales have promise for purification and confined reactions, and as starting points for fabricating highly ordered crystals for protein engineering and drug discovery applications. However, developing controlled crystallization techniques from batch processes remain challenging. We show that neutrally charged nanoscale spherical micelles from biocompatible nonionic surfactant solutions can evolve into nano- and micro-sized branched networks and crystal-like structures. This occurs under simple combinations of temperature and flow conditions. Our findings not only suggest new opportunities for developing controlled universal crystallization and encapsulation procedures that are sensitive to ionic environments and high temperatures, but also open up new pathways for accelerating drug discovery processes, which are of tremendous interest to pharmaceutical and biotechnological industries.

  10. Carotenoids from Haloarchaea and Their Potential in Biotechnology

    Science.gov (United States)

    Rodrigo-Baños, Montserrat; Garbayo, Inés; Vílchez, Carlos; Bonete, María José; Martínez-Espinosa, Rosa María

    2015-01-01

    The production of pigments by halophilic archaea has been analysed during the last half a century. The main reasons that sustains this research are: (i) many haloarchaeal species possess high carotenoids production availability; (ii) downstream processes related to carotenoid isolation from haloarchaea is relatively quick, easy and cheap; (iii) carotenoids production by haloarchaea can be improved by genetic modification or even by modifying several cultivation aspects such as nutrition, growth pH, temperature, etc.; (iv) carotenoids are needed to support plant and animal life and human well-being; and (v) carotenoids are compounds highly demanded by pharmaceutical, cosmetic and food markets. Several studies about carotenoid production by haloarchaea have been reported so far, most of them focused on pigments isolation or carotenoids production under different culture conditions. However, the understanding of carotenoid metabolism, regulation, and roles of carotenoid derivatives in this group of extreme microorganisms remains mostly unrevealed. The uses of those haloarchaeal pigments have also been poorly explored. This work summarises what has been described so far about carotenoids production by haloarchaea and their potential uses in biotechnology and biomedicine. In particular, new scientific evidence of improved carotenoid production by one of the better known haloarchaeon (Haloferax mediterranei) is also discussed. PMID:26308012

  11. Energy transfer from carotenoids to bacteriochlorophylls

    Czech Academy of Sciences Publication Activity Database

    Frank, H.A.; Polívka, Tomáš

    Dordrecht : Springer, 2008 - (Hunter, C.; Daldal, F.; Thurnauer, M.; Beatty, J.), s. 218-230 ISBN 978-1-4020-8814-8. - (Advances in Photosynthesis and Respiration. 28) Institutional research plan: CEZ:AV0Z50510513 Keywords : carotenoids * Energy transfer Subject RIV: BO - Biophysics

  12. Excited state properties of aryl carotenoids

    Czech Academy of Sciences Publication Activity Database

    Fuciman, M.; Chábera, P.; Župčanová, Anita; Hříbek, P.; Arellano, J.B.; Vácha, František; Pšenčík, J.; Polívka, Tomáš

    2010-01-01

    Roč. 12, č. 13 (2010), s. 3112-3120. ISSN 1463-9076 R&D Projects: GA AV ČR IAA608170604 Institutional research plan: CEZ:AV0Z50510513 Keywords : carotenoids * excited-states * femtosecond spectroscopy Subject RIV: BO - Biophysics Impact factor: 3.454, year: 2010

  13. Carotenoid excited states - beyond the standard model

    Czech Academy of Sciences Publication Activity Database

    Polívka, Tomáš

    Göttingen : University of Göttingen, 2007. s. 25. [CERC3 Young Chemists Workshop "Time-resolved methods for studies of chemical reactions". 25.04.2007-27.04.2007, Göttingen] Keywords : Carotenoids Subject RIV: BO - Biophysics

  14. Long-lived coherence in carotenoids

    International Nuclear Information System (INIS)

    We use two-colour vibronic coherence spectroscopy to observe long-lived vibrational coherences in the ground electronic state of carotenoid molecules, with decoherence times in excess of 1 ps. Lycopene and spheroidene were studied isolated in solution, and within the LH2 light-harvesting complex extracted from purple bacteria. The vibrational coherence time is shown to increase significantly for the carotenoid in the complex, providing further support to previous assertions that long-lived electronic coherences in light-harvesting complexes are facilitated by in-phase motion of the chromophores and surrounding proteins. Using this technique, we are also able to follow the evolution of excited state coherences and find that for carotenoids in the light-harvesting complex the (S2|S0) superposition remains coherent for more than 70 fs. In addition to the implications of this long electronic decoherence time, the extended coherence allows us to observe the evolution of the excited state wavepacket. These experiments reveal an enhancement of the vibronic coupling to the first vibrational level of the C-C stretching mode and/or methyl-rocking mode in the ground electronic state 70 fs after the initial excitation. These observations open the door to future experiments and modelling that may be able to resolve the relaxation dynamics of carotenoids in solution and in natural light-harvesting systems.

  15. Continuous production of carotenoids from Dunaliella salina

    NARCIS (Netherlands)

    Kleinegris, D.M.M.; Janssen, M.G.J.; Brandenburg, W.A.; Wijffels, R.H.

    2011-01-01

    During the in situ extraction of ß-carotene from Dunaliella salina, the causal relationship between carotenoid extraction and cell death indicated that cell growth and cell death should be at equilibrium for a continuous in situ extraction process. In a flat-panel photobioreactor that was operated a

  16. Glass formation and crystallization in high-temperature glass-ceramics and Si3N4

    Science.gov (United States)

    Drummond, Charles H., III

    1991-08-01

    The softening of glassy grain boundaries in ceramic matrix composites and Si3N4 at high temperatures reduces mechanical strength and the upper-use temperature. By crystallizing this glass to a more refractory crystalline phase, a material which performs at higher temperatures may result. Three systems were examined: a cordierite composition with ZrO2 as a nucleating agent; celsian compositions; and yttrium silicate glasses both in bulk and intergranular in Si3N4. For the cordierite compositions, a series of metastable phases was obtained. The crystallization of these compositions was summarized in terms of metastable ternary isothermal sections. Zircon formed at the expense of ZrO2 and spinel. In SiC composites, the transformations were slower. In celsian, two polymorphs were crystallized. One phase, hexacelsian, which always crystallized, even when metastable, had an undesirable volume change. The other phase, celsian, was very difficult to crystallize. In yttrium silicate bulk glasses, similar in composition to the intergranular glass in Si3N4, a number of polymorphs of Y2Si2O7 were crystallized. The conditions under which these polymorphs formed are compared with crystallization in Si3N4.

  17. Glass formation and crystallization in high-temperature glass-ceramics and Si3N4

    Science.gov (United States)

    Drummond, Charles H., III

    1991-01-01

    The softening of glassy grain boundaries in ceramic matrix composites and Si3N4 at high temperatures reduces mechanical strength and the upper-use temperature. By crystallizing this glass to a more refractory crystalline phase, a material which performs at higher temperatures may result. Three systems were examined: a cordierite composition with ZrO2 as a nucleating agent; celsian compositions; and yttrium silicate glasses both in bulk and intergranular in Si3N4. For the cordierite compositions, a series of metastable phases was obtained. The crystallization of these compositions was summarized in terms of metastable ternary isothermal sections. Zircon formed at the expense of ZrO2 and spinel. In SiC composites, the transformations were slower. In celsian, two polymorphs were crystallized. One phase, hexacelsian, which always crystallized, even when metastable, had an undesirable volume change. The other phase, celsian, was very difficult to crystallize. In yttrium silicate bulk glasses, similar in composition to the intergranular glass in Si3N4, a number of polymorphs of Y2Si2O7 were crystallized. The conditions under which these polymorphs formed are compared with crystallization in Si3N4.

  18. What are carotenoids signaling? Immunostimulatory effects of dietary vitamin E, but not of carotenoids, in Iberian green lizards

    Science.gov (United States)

    Kopena, Renata; López, Pilar; Martín, José

    2014-12-01

    In spite that carotenoid-based sexual ornaments are one of the most popular research topics in sexual selection of animals, the antioxidant and immunostimulatory role of carotenoids, presumably signaled by these colorful ornaments, is still controversial. It has been suggested that the function of carotenoids might not be as an antioxidant per se, but that colorful carotenoids may indirectly reflect the levels of nonpigmentary antioxidants, such as melatonin or vitamin E. We experimentally fed male Iberian green lizards ( Lacerta schreiberi) additional carotenoids or vitamin E alone, or a combination of carotenoids and vitamin E dissolved in soybean oil, whereas a control group only received soybean oil. We examined the effects of the dietary supplementations on phytohaemagglutinin (PHA)-induced skin-swelling immune response and body condition. Lizards that were supplemented with vitamin E alone or a combination of vitamin E and carotenoids had greater immune responses than control lizards, but animals supplemented with carotenoids alone had lower immune responses than lizards supplemented with vitamin E and did not differ from control lizards. These results support the hypothesis that carotenoids in green lizards are not effective as immunostimulants, but that they may be visually signaling the immunostimulatory effects of non-pigmentary vitamin E. In contrast, lizards supplemented with carotenoids alone have higher body condition gains than lizards in the other experimental groups, suggesting that carotenoids may be still important to improve condition.

  19. Identification and Characterization of Genes Involved in Embryonic Crystal Cell Formation During Drosophila Hematopoiesis

    Science.gov (United States)

    Milchanowski, Allison B.; Henkenius, Amy L.; Narayanan, Maya; Hartenstein, Volker; Banerjee, Utpal

    2004-01-01

    Parallels between vertebrate and Drosophila hematopoiesis add to the value of flies as a model organism to gain insights into blood development. The Drosophila hematopoietic system is composed of at least three classes of terminally differentiated blood cells: plasmatocytes, crystal cells, and lamellocytes. Recent studies have identified transcriptional and signaling pathways in Drosophila involving proteins similar to those seen in human blood development. To identify additional genes involved in Drosophila hematopoiesis, we have conducted a P-element-based genetic screen to isolate mutations that affect embryonic crystal cell development. Using a marker of terminally differentiated crystal cells, we screened 1040 P-element-lethal lines located on the second and third chromosomes and identified 44 individual lines that affect crystal cell development. Identifying novel genes and pathways involved in Drosophila hematopoiesis is likely to provide further insights into mammalian hematopoietic development and disorders. PMID:15454546

  20. Unsaturated Glycerophospholipids Mediate Heme Crystallization: Biological Implications for Hemozoin Formation in the Kissing Bug Rhodnius prolixus

    DEFF Research Database (Denmark)

    Stiebler, R.; Majerowicz, D.; Knudsen, Jens;

    2014-01-01

    Hemozoin (Hz) is a heme crystal produced by some blood-feeding organisms, as an efficient way to detoxify heme derived from hemoglobin digestion. In the triatomine insect Rhodnius prolixus, Hz is essentially produced by midgut extracellular phospholipid membranes known as perimicrovillar membranes...... (PMVM). Here, we investigated the role of commercial glycerophospholipids containing serine, choline and ethanolamine as headgroups and R. prolixus midgut lipids (RML) in heme crystallization. All commercial unsaturated forms of phospholipids, as well as RML, mediated fast and efficient beta...... induced by uPE, and the other largely represented by crystals with numerous sharp edges and tapered ends. Heme crystallization reactions induced by RML were efficient, with a heme to beta-hematin conversion rate higher than 70%, but clearly slower (t1/2 of 9.9-17.7 minutes) than those induced by uPC and u...

  1. A novel carotenoid cleavage activity involved in the biosynthesis of Citrus fruit-specific apocarotenoid pigments

    KAUST Repository

    Rodrigo, María J.

    2013-09-04

    Citrus is the first tree crop in terms of fruit production. The colour of Citrus fruit is one of the main quality attributes, caused by the accumulation of carotenoids and their derivative C30 apocarotenoids, mainly ?-citraurin (3-hydroxy-?-apo-8?-carotenal), which provide an attractive orange-reddish tint to the peel of oranges and mandarins. Though carotenoid biosynthesis and its regulation have been extensively studied in Citrus fruits, little is known about the formation of C30 apocarotenoids. The aim of this study was to the identify carotenoid cleavage enzyme(s) [CCD(s)] involved in the peel-specific C30 apocarotenoids. In silico data mining revealed a new family of five CCD4-type genes in Citrus. One gene of this family, CCD4b1, was expressed in reproductive and vegetative tissues of different Citrus species in a pattern correlating with the accumulation of C30 apocarotenoids. Moreover, developmental processes and treatments which alter Citrus fruit peel pigmentation led to changes of ?-citraurin content and CCD4b1 transcript levels. These results point to the involvement of CCD4b1 in ?-citraurin formation and indicate that the accumulation of this compound is determined by the availability of the presumed precursors zeaxanthin and ?-cryptoxanthin. Functional analysis of CCD4b1 by in vitro assays unequivocally demonstrated the asymmetric cleavage activity at the 7?,8? double bond in zeaxanthin and ?-cryptoxanthin, confrming its role in C30 apocarotenoid biosynthesis. Thus, a novel plant carotenoid cleavage activity targeting the 7?,8? double bond of cyclic C40 carotenoids has been identified. These results suggest that the presented enzyme is responsible for the biosynthesis of C30 apocarotenoids in Citrus which are key pigments in fruit coloration. The Author 2013.

  2. Mate choice for a male carotenoid-based ornament is linked to female dietary carotenoid intake and accumulation

    Directory of Open Access Journals (Sweden)

    Toomey Matthew B

    2012-01-01

    Full Text Available Abstract Background The coevolution of male traits and female mate preferences has led to the elaboration and diversification of sexually selected traits; however the mechanisms that mediate trait-preference coevolution are largely unknown. Carotenoid acquisition and accumulation are key determinants of the expression of male sexually selected carotenoid-based coloration and a primary mechanism maintaining the honest information content of these signals. Carotenoids also influence female health and reproduction in ways that may alter the costs and benefits of mate choice behaviours and thus provide a potential biochemical link between the expression of male traits and female preferences. To test this hypothesis, we manipulated the dietary carotenoid levels of captive female house finches (Carpodacus mexicanus and assessed their mate choice behavior in response to color-manipulated male finches. Results Females preferred to associate with red males, but carotenoid supplementation did not influence the direction or strength of this preference. Females receiving a low-carotenoid diet were less responsive to males in general, and discrimination among the colorful males was positively linked to female plasma carotenoid levels at the beginning of the study when the diet of all birds was carotenoid-limited. Conclusions Although female preference for red males was not influenced by carotenoid intake, changes in mating responsiveness and discrimination linked to female carotenoid status may alter how this preference is translated into choice. The reddest males, with the most carotenoid rich plumage, tend to pair early in the breeding season. If carotenoid-related variations in female choice behaviour shift the timing of pairing, then they have the potential to promote assortative mating by carotenoid status and drive the evolution of carotenoid-based male plumage coloration.

  3. Formation of large (≃100 μm) ice crystals near the tropical tropopause

    OpenAIRE

    E. J. Jensen; Pfister, L; Bui, T. V.; Lawson, P.; Baker, B.; Mo, Q.; D. Baumgardner; E. M. Weinstock; Smith, J. B.; Moyer, E.J.; Hanisco, T. F.; Sayres, D. S.; Clair, J. M. St.; M. J. Alexander; O. B. Toon

    2008-01-01

    Recent high-altitude aircraft measurements with in situ imaging instruments indicated the presence of relatively large (≃100 μm length), thin (aspect ratios of ≃6:1 or larger) hexagonal plate ice crystals near the tropical tropopause in very low concentrations (<0.01 L−1). These crystals were not produced by deep convection or aggregation. We use simple growth-sedimentation calculations as well as detailed cloud simulations to evaluate the condit...

  4. On the use of classical JMAK crystallization kinetic theory to describe simultaneous processes leading to the formation of different phases in metals

    OpenAIRE

    Blázquez, J.S.; Conde, C. F.; Conde, A.

    2014-01-01

    The classical theory of Johnson–Mehl–Avrami–Kolmogorov (JMAK) is widely used to describe the kinetics of crystallization even when the premises required for its application are not strictly fulfilled. In this paper we propose a procedure to obtain the JMAK parameters of the independent transformations that simultaneously occur during a crystallization process (e.g. leading to the formation of several crystalline phases). The predictions of the analysis have been used to describe the crystalli...

  5. Small-angle neutron scattering measurements of deuteride (hydride) formation and decomposition in single-crystal Pd

    International Nuclear Information System (INIS)

    The deuteride (hydride) precipitation and decomposition microstructure in single-crystal Pd has been investigated in a series of in situ small-angle neutron scattering (SANS) measurements. The particle morphology along the absorption and desorption branches of the 353-K pressure-composition isotherm are consistent with a loss of particle coherency, leading to the formation of large, micron-thick plates. The loss of coherency coincides with the system entering the miscibility gap, an observation that suggests irreversible dislocation formation in part drives the hysteretic behavior of the Pd-D (-H) system. SANS analysis further indicates that the decomposition process is characterized by a much higher particle dispersion, with a factor of 40 greater surface-to-volume ratio of the precipitating phase. This we attribute to a more heterogeneous transformation process, presumably at dislocations formed during initial deuteride formation

  6. Thermal formation of mesoporous single-crystal Co3O4 nano-needles and their lithium storage properties

    KAUST Repository

    Lou, Xiong Wen

    2008-01-01

    In this work, we report the simple solid-state formation of mesoporous Co3O4 nano-needles with a 3D single-crystalline framework. The synthesis is based on controlled thermal oxidative decomposition and re-crystallization of precursor β-Co(OH)2 nano-needles. Importantly, after thermal treatment, the needle-like morphology can be completely preserved, despite the fact that there is a large volume contraction accompanying the process: β-Co(OH)2 → Co3O 4. Because of the intrinsic crystal contraction, a highly mesoporous structure with high specific surface area has been simultaneously created. The textual properties can be easily tailored by varying the annealing temperature between 200-400 °C. Interestingly, thermal re-crystallization at higher temperatures leads to the formation of a perfect 3D single-crystalline framework. Thus derived mesoporous Co3O4 nano-needles serve as a good model system for the study of lithium storage properties. The optimized sample manifests very low initial irreversible loss (21%), ultrahigh capacity, and excellent cycling performance. For example, a reversible capacity of 1079 mA h g-1 can be maintained after 50 cycles. The superior electrochemical performance and ease of synthesis may suggest their practical use in lithium-ion batteries. © The Royal Society of Chemistry 2008.

  7. In-situ, variable thickness, liquid crystal film target formation at moderate repetition rate for intense laser applications

    CERN Document Server

    Poole, P L; Cochran, G E; Hanna, R J; Andereck, C D; Schumacher, D W

    2015-01-01

    Liquid crystal films have recently been demonstrated as variable thickness, planar targets for ultra-intense laser matter experiments and applications such as ion acceleration. By controlling the parameters of film formation, including liquid crystal temperature and volume, their thickness can be varied on-demand from 10 $nm$ to above 10 $\\mu m$. This thickness range enables for the first time real-time selection and optimization of various ion acceleration mechanisms using low cost, high quality targets. Our previous work employed these targets in single shot configuration, requiring chamber cycling after the pre-made films were expended. Presented here is a film formation device capable of drawing films from a bulk liquid crystal source volume to any thickness in the aforementioned range. This device will form films under vacuum within 2 $\\mu m$ of the same location each time, well within the Rayleigh range of even tight $F/ \\#$ systems. The repetition rate of the device exceeds 0.1 $Hz$ for sub-100 $nm$ fi...

  8. Out-of-equilibrium processes in suspensions of oppositely charged colloids: liquid-to-crystal nucleation and gel formation

    International Nuclear Information System (INIS)

    We study the kinetics of the liquid-to-crystal transformation and of gel formation in colloidal suspensions of oppositely charged particles. We analyse, by means of both computer simulations and experiments, the evolution of a fluid quenched to a state point of the phase diagram where the most stable state is either a homogeneous crystalline solid or a solid phase in contact with a dilute gas. On the one hand, at high temperatures and high packing fractions, close to a substitutionally-ordered/substitutionally-disordered solid-solid coexistence line, we find that the fluid-to-crystal pathway does not follow the minimum free energy route. On the other hand, a quench to a state point far from the substitutionally-ordered/substitutionally-disordered crystal coexistence border is followed by a fluid-to-solid transition through the minimum free energy pathway. At low temperatures and packing fractions we observe that the system undergoes a gas-liquid spinodal decomposition that, at some point, stops, giving rise to a gel-like structure. Both our simulations and experiments suggest that increasing the interaction range favours crystallization over vitrification in gel-like structures.

  9. Carotenoid Production by Halophilic Archaea Under Different Culture Conditions.

    Science.gov (United States)

    Calegari-Santos, Rossana; Diogo, Ricardo Alexandre; Fontana, José Domingos; Bonfim, Tania Maria Bordin

    2016-05-01

    Carotenoids are pigments that may be used as colorants and antioxidants in food, pharmaceutical, and cosmetic industries. Since they also benefit human health, great efforts have been undertaken to search for natural sources of carotenoids, including microbial ones. The optimization of culture conditions to increase carotenoid yield is one of the strategies used to minimize the high cost of carotenoid production by microorganisms. Halophilic archaea are capable of producing carotenoids according to culture conditions. Their main carotenoid is bacterioruberin with 50 carbon atoms. In fact, the carotenoid has important biological functions since it acts as cell membrane reinforcement and it protects the microorganism against DNA damaging agents. Moreover, carotenoid extracts from halophilic archaea have shown high antioxidant capacity. Therefore, current review summarizes the effect of different culture conditions such as salt and carbon source concentrations in the medium, light incidence, and oxygen tension on carotenoid production by halophilic archaea and the strategies such as optimization methodology and two-stage cultivation already used to increase the carotenoid yield of these microorganisms. PMID:26750123

  10. Carotenoids intake and asthma prevalence in Thai children

    Directory of Open Access Journals (Sweden)

    Sanguansak Rerksuppaphol

    2012-02-01

    Full Text Available Several antioxidant nutrients have been described to inversely correlate with asthma. In order to quantify the intake of these substances, it is possible to measure skin levels by Raman spectroscopy, a novel non-invasive technique that can also be used in children. This cross-sectional school-based study involved 423 children from a rural area of Thailand. Asthmatic children were diagnosed according to a Health Interview for Asthma Control questionnaire. Skin carotenoid levels were measured with Raman spectroscopy. Demographic data were obtained by directly interviewing children and their parents, whereas anthropometric parameters were measured by trained staff. Intake of carotenoids, vitamin A and C were evaluated by a food frequency questionnaire. Overall incidence of asthma in Thai schoolchildren (aged 3.5-17.8 years was 17.3%. There was no significant difference in dietary intake of carotenoids and vitamin A and C, and skin carotenoid level between asthmatic and nonasthmatic children. Skin carotenoid level significantly correlated with all carotenoids and vitamin A intake (P<0.05. Carotenoids and vitamin A and C intakes, and skin carotenoid levels were not associated with the risk of asthma in Thai children. Skin carotenoids correlated with all carotenoids and vitamin A intake in mild to moderate degrees. Raman spectroscopy was confirmed to be a useful tool to determine antioxidant skin levels.

  11. Quantitative auger electron spectroscopy of the interface carbon layer formation on the vacuum cleavage surfaces of layered semiconductor In4Se3 crystals

    International Nuclear Information System (INIS)

    The results of the qualitative Auger electron spectroscopy of the interface carbon layer formation on the high vacuum cleavage surfaces of layered semiconductor In4Se3 crystals are presented. The kinetics of interfacial carbon layer formation on the cleavage surfaces of crystals and the elemental and phase composition of the interface dependent on the exposition time in high vacuum and on the dose of electron irradiation have been studied by the quantitative Auger electron and mass-spectroscopy methods

  12. Structure Formation of Ultrathin PEO Films at Solid Interfaces—Complex Pattern Formation by Dewetting and Crystallization

    Directory of Open Access Journals (Sweden)

    Hans-Georg Braun

    2013-02-01

    Full Text Available The direct contact of ultrathin polymer films with a solid substrate may result in thin film rupture caused by dewetting. With crystallisable polymers such as polyethyleneoxide (PEO, molecular self-assembly into partial ordered lamella structures is studied as an additional source of pattern formation. Morphological features in ultrathin PEO films (thickness < 10 nm result from an interplay between dewetting patterns and diffusion limited growth pattern of ordered lamella growing within the dewetting areas. Besides structure formation of hydrophilic PEO molecules, n-alkylterminated (hydrophobic PEO oligomers are investigated with respect to self-organization in ultrathin films. Morphological features characteristic for pure PEO are not changed by the presence of the n-alkylgroups.

  13. Formation and crystallization of bulk Pd82Si18 amorphous alloys

    Institute of Scientific and Technical Information of China (English)

    蒲建; 王敬丰; 肖建中; 崔昆

    2003-01-01

    Bulk amorphous Pd82Si18 alloy with the largest diameter of 8 mm was prepared by water quenching the molten alloy with flux medium in a quartz tube. The calculation result indicates that the bulk Pd82Si18 amorphous alloys have a low critical cooling rate (Rc) of 4.589 K/s or less. The experimental results show that purifying melt may improve glass forming ability(GFA) of undercooled melt, while liquid phase separation (LPS) of undercooled melt will decrease its GFA. There are some differences in crystallization experiments between bulk metallic glass and amorphous ribbons of Pd82Si18 alloys. These include the numbers of exothermic peak, glass transition temperature Tg, crystallization temperature Tx, region of undercooling liquid (ΔT=Tx-Tg) respectively. The links of cooling rates of melt and crystallization of Pd82Si18 amorphous alloys are explored.

  14. Metallic Na formation in NaCl crystals with irradiation of electron or vacuum ultraviolet photon

    Energy Technology Data Exchange (ETDEWEB)

    Owaki, Shigehiro [Osaka Prefecture Univ., Sakai, Osaka (Japan). Coll. of Integrated Arts and Sciences; Koyama, Shigeko; Takahashi, Masao; Kamada, Masao; Suzuki, Ryouichi

    1997-03-01

    Metallic Na was formed in NaCl single crystals with irradiation of a variety of radiation sources and analyzed the physical states with several methods. In the case of irradiation of 21 MeV electron pulses to the crystal blocks, the optical absorption and lifetime measurement of positron annihilation indicated appearance of Na clusters inside. Radiation effects of electron beam of 30 keV to the crystals in vacuum showed the appearance of not only metallic Na but atomic one during irradiation with Auger electron spectroscopy. Intense photon fluxes in vacuum ultraviolet region of synchrotron radiation were used as another source and an analyzing method of ultraviolet photoelectron spectroscopy. The results showed the metallic Na layered so thick that bulk plasmon can exist. (author)

  15. Accidental formation of Gd₄(SiO₄)₂OTe: crystal structure and spectroscopic properties.

    Science.gov (United States)

    Daszkiewicz, Marek; Gulay, Lubomir D

    2015-07-01

    Designing new functional materials with increasingly complex compositions is of current interest in science and technology. Complex rare-earth-based chalcogenides have specific thermal, electrical, magnetic and optical properties. Tetragadolinium bis[tetraoxidosilicate(IV)] oxide telluride, Gd4(SiO4)2OTe, was obtained accidentally while studying the Gd2Te3-Cu2Te system. The crystal structure was determined by means of single-crystal X-ray diffraction. The compound crystallizes in the space group Pnma. Three symmetry-independent gadolinium sites were determined. The excitation and emission spectra were collected at room temperature and at 10 K. Gd4(SiO4)2OTe appears to be a promising optical material when doped with rare-earth ions. PMID:26146399

  16. Evidence of Epigenetic Mechanisms Affecting Carotenoids.

    Science.gov (United States)

    Arango, Jacobo; Beltrán, Jesús; Nuñez, Jonathan; Chavarriaga, Paul

    2016-01-01

    Epigenetic mechanisms are able to regulate plant development by generating non-Mendelian allelic interactions. An example of these are the responses to environmenal stimuli that result in phenotypic variability and transgression amongst important crop traits. The need to predict phenotypes from genotypes to understand the molecular basis of the genotype-by-environment interaction is a research priority. Today, with the recent discoveries in the field of epigenetics, this challenge goes beyond analyzing how DNA sequences change. Here we review examples of epigenetic regulation of genes involved in carotenoid synthesis and degradation, cases in which histone- and/or DNA-methylation, and RNA silencing at the posttranscriptional level affect carotenoids in plants. PMID:27485227

  17. Out-of-equilibrium processes in suspensions of oppositely charged colloids: liquid-to-crystal nucleation and gel formation

    Science.gov (United States)

    Sanz, Eduardo

    2009-03-01

    We study the kinetics of the liquid-to-crystal transformation and of gel formation in colloidal suspensions of oppositely charged particles. We analyse, by means of both computer simulations and experiments, the evolution of a fluid quenched to a state point of the phase diagram where the most stable state is either a homogeneous crystalline solid or a solid phase in contact with a dilute gas. On the one hand, at high temperatures and high packing fractions, close to an ordered-solid/disordered-solid coexistence line, we find that the fluid-to-crystal pathway does not follow the minimum free energy route. On the other hand, a quench to a state point far from the ordered-crystal/disordered-crystal coexistence border is followed by a fluid-to-solid transition through the minimum free energy pathway. At low temperatures and packing fractions we observe that the system undergoes a gas-liquid spinodal decomposition that, at some point, arrests giving rise to a gel-like structure. Both our simulations and experiments suggest that increasing the interaction range favors crystallization over vitrification in gel-like structures. [4pt] In collaboration with Chantal Valeriani, Soft Condensed Matter, Debye Institute for Nanomaterials Science, Utrecht University, Princetonplein 5, 3584 CC Utrecht, The Netherlands and SUPA, School of Physics, University of Edinburgh, JCMB King's Buildings, Mayfield Road, Edinburgh EH9 3JZ, UK; Teun Vissers, Andrea Fortini, Mirjam E. Leunissen, and Alfons van Blaaderen, Soft Condensed Matter, Debye Institute for Nanomaterials Science, Utrecht University; Daan Frenke, FOM Institute for Atomic and Molecular Physics, Kruislaan 407, 1098 SJ Amsterdam, The Netherlands and Department of Chemistry, University of Cambridge, Lensfield Road, CB2 1EW, Cambridge, UK; and Marjolein Dijkstra, Soft Condensed Matter, Debye Institute for Nanomaterials Science, Utrecht University.

  18. Macular and serum carotenoid concentrations in patients with malabsorption syndromes.

    Science.gov (United States)

    Ward, Matthew S; Zhao, Da You; Bernstein, Paul S

    2008-03-01

    The carotenoids lutein and zeaxanthin are believed to protect the human macula by absorbing blue light and quenching free radicals. Intestinal malabsorption syndromes such as celiac and Crohn's disease are known to cause deficiencies of lipid-soluble nutrients. We hypothesized that subjects with nutrient malabsorption syndromes will demonstrate lower carotenoid levels in the macula and blood, and that these lower levels may correlate with early-onset maculopathy. Resonance Raman spectrographic (RRS) measurements of macular carotenoid levels were collected from subjects with and without a history of malabsorption syndromes. Carotenoids were extracted from serum and analyzed by high performance liquid chromatography (HPLC). Subjects with malabsorption (n = 22) had 37% lower levels of macular carotenoids on average versus controls (n = 25, P maculopathy were not observed. We conclude that intestinal malabsorption results in lower macular carotenoid levels. PMID:19081745

  19. Raman spectra of carotenoids in natural products

    Science.gov (United States)

    Withnall, Robert; Chowdhry, Babur Z.; Silver, Jack; Edwards, Howell G. M.; de Oliveira, Luiz F. C.

    2003-08-01

    Resonance Raman spectra of naturally occurring carotenoids have been obtained from nautilus, periwinkle ( Littorina littorea) and clam shells under 514.5 nm excitation and these spectra are compared with the resonance Raman spectra obtained in situ from tomatoes, carrots, red peppers and saffron. The tomatoes, carrots and red peppers gave rise to resonance Raman spectra exhibiting a ν1 band at ca. 1520 cm -1, in keeping with its assignment to carotenoids with ca. nine conjugated carboncarbon double bonds in their main chains, whereas the resonance Raman spectrum of saffron showed a ν1 band at 1537 cm -1 which can be assigned to crocetin, having seven conjugated carboncarbon double bonds. A correlation between ν1 wavenumber location and effective conjugated chain length has been used to interpret the data obtained from the shells, and the wavenumber position (1522 cm -1) of the ν1 band of the carotenoid in the orange clam shell suggests that it contains nine conjugated double bonds in the main chain. However, the black periwinkle and nautilus shells exhibit ν1 bands at 1504 and 1496 cm -1, respectively. On the basis of the correlation between ν1 wavenumber location and effective conjugated chain length, this indicates that they contain carotenoids with longer conjugated chains, the former having ca. 11 double bonds and the latter ca. 13 or even more. Raman spectra of the nautilus, periwinkle and clam shells also exhibited a strong band at 1085 cm -1 and a doublet with components at 701 and 705 cm -1, which can be assigned to biogenic calcium carbonate in the aragonite crystallographic form.

  20. A Unified Picture of S* in Carotenoids.

    Science.gov (United States)

    Balevičius, Vytautas; Abramavicius, Darius; Polívka, Tomáš; Galestian Pour, Arpa; Hauer, Jürgen

    2016-09-01

    In π-conjugated chain molecules such as carotenoids, coupling between electronic and vibrational degrees of freedom is of central importance. It governs both dynamic and static properties, such as the time scales of excited state relaxation as well as absorption spectra. In this work, we treat vibronic dynamics in carotenoids on four electronic states (|S0⟩, |S1⟩, |S2⟩, and |Sn⟩) in a physically rigorous framework. This model explains all features previously associated with the intensely debated S* state. Besides successfully fitting transient absorption data of a zeaxanthin homologue, this model also accounts for previous results from global target analysis and chain length-dependent studies. Additionally, we are able to incorporate findings from pump-deplete-probe experiments, which were incompatible to any pre-existing model. Thus, we present the first comprehensive and unified interpretation of S*-related features, explaining them by vibronic transitions on either S1, S0, or both, depending on the chain length of the investigated carotenoid. PMID:27509302

  1. Study of transitory forms of carotenoids

    International Nuclear Information System (INIS)

    In order to explain the biological role of the carotenoids their transitory forms were studied with an apparatus measuring the small (∼10-3) short-lived (100 ns to 1 ms) optical density variations obtained by excitation with a ruby laser. Two forms were studied: a) Triplet state 3Car. - This state (t1/2∼6 μs) is obtained not by direct excitation but by T-T energy transfer from chlorophyll, in different media (chloroplasts, pigments in solution or in micelle). Two arguments can be advanced to explain in terms of triplet energy transfer an essential biological role of carotenoids, protection against photodynamic effects: - the energy level of 3Car is lower than that of the singlet of oxygen; - in vivo the T-T transfer from chlorophyll to the carotenoids is very fast: 30 ns.. b) Radical cation Car+. - This form is obtained by electron transfer from carotene to the triplet of Toluidine Blue, in ethanol. Car+ (t1/2∼200 μs) shows a strong absorption band at 910 nm. The properties of Car+ are discussed in relation to other polyene derivatives and to hydrocarbon ions. Car+ could be involved in certain biological electron transfers. (author)

  2. Optimization of carotenoids extraction from Penaeus semisulcatus shrimp wastes

    OpenAIRE

    Gholamreza jahed Khaniki; Parisa Sadighara; Ramin Nabizadeh Nodehi; Mahmood Alimohammadi; Naiema Vakili Saatloo

    2013-01-01

    Objective: To find effective method for carotenoids extraction from shrimp waste which is one of the important sources of natural carotenoids and produced in large quantities in Iran. Methods: Two methods of carotenoids extraction, enzymatic and alkaline (NaOH 1 normal) treatment, were assayed. About 5 g of gritted shrimp wastes were used at each stage. For alkaline treatment, sodium hydroxide were added to shrimp waste. After 48 h, the mixture was filtered and centrifuged. ...

  3. Structure of the principal carotenoid pigment of Cellulomonas biazotea.

    OpenAIRE

    Weeks, O B; Montes, A R; Andrewes, A G

    1980-01-01

    The yellow-pigmented Cellulomonas biazotea, ATCC 486, contains a mixture of carotenoids. The principal compound is a decapreno carotenoid (C50H72O2) tentatively characterized as 2,2'-bis(4-hydroxy-3-methyl-2-butenyl)-gamma,gamma-carotene on the basis of electronic absorption, infrared, proton magnetic resonance, and mass spectrometries. The carotenoid is presumed to be identical to sarcinaxanthin from Sarcina lutea pro-synon. Micrococcus luteus and, therefore, is isomeric with decaprenoxanthi...

  4. Dietary carotenoids in normal and pathological tissues of corpus uteri.

    Directory of Open Access Journals (Sweden)

    Sławomir Wołczyński

    2008-12-01

    Full Text Available Carotenoids and retinyl esters are the source of vitamin A in the human body and its natural derivatives takes part in the regulation of cell replication and differentiation in the human endometrium, may induce the leiomyoma growth and has a role in differentiation of endometrial adenocarcinoma. The aim of the study was to demonstrate the presence of carotenoids in tissues from the normal uterus and from various tumors of the uterine corpus, as well as to compare the total content, major carotenoids and % of carotenoids belonging to the provitamin A group between the tissues examined. Using three independent methods of chromatography (CC, TLC, HPLC we analysed 140 human samples. We identified 13 carotenoids belonging to the eg. provitamin A group and epoxy carotenoids. In all the samples beta-carotene, beta-cryptoxanthin, lutein, neoxanthin, violaxanthin and mutatoxanthin were isolated. In normal tissues, the mean carotenoid content was the highest in the follicular phase endometrium (9.9 microg/g, while the highest percentage of carotenoids belonging to provitamin A group was found in the luteal phase (18.2%. In the pathological group, the highest mean values were demonstrated for epithelial lesions (8.0 microg/g, and within this group - in endometrioid adenocarcinoma (10.8 microg/g. In both groups, violaxanthin, beta-cryptoxanthin, lutein epoxide and mutatoxanthin were the predominant carotenoids. We have demonstrated that all uterine tissues show a concentration of beta-carotene and beta-cryptoxanthin, being the source of vitamin A. The highest total values of carotenoids obtained in the group of endometrioid adenocarcinoma seem to confirm certain enzymatic defects in carotenoid metabolism in the course of the neoplastic process or some metabolic modifications. The finding of astaxanthin - the major antioxidant among carotenoids - in 63% of tissues examined is also significant.

  5. Effects of added silica nanoparticles on the nematic liquid crystal phase formation in beidellite suspensions

    NARCIS (Netherlands)

    Landman, Jasper; Paineau, Erwan; Davidson, Patrick; Bihannic, Isabelle; Michot, Laurent J.; Philippe, Adrian Marie; Petukhov, Andrei V.; Lekkerkerker, Henk N W

    2014-01-01

    In this article, we present a study of the liquid crystal phase behavior of mixed suspensions of the natural smectite clay mineral beidellite and nonadsorbing colloidal silica particles. While virtually all smectite clays dispersed in water form gels at very low concentrations, beidellite displays a

  6. Formation of tilted smectic-C liquid crystal phase in polar Gay-Berne molecules

    International Nuclear Information System (INIS)

    We perform molecular dynamics simulation for a system of Gay-Berne molecules having two terminal dipole moments to generate tilted smectic-C liquid crystal phase. We investigate the effect of dipolar orientation with respect to the long molecular axis on phase behaviour. The study indicates that larger dipolar angle can give rise to greater tilt in molecular organization within a layer

  7. Formation of grain boundaries in magnesium single crystal during equal channel angular pressing

    Czech Academy of Sciences Publication Activity Database

    Šedá, P.; Jäger, Aleš; Lejček, Pavel; Triguero, P.R.

    2014-01-01

    Roč. 94, č. 10 (2014), s. 1095-1111. ISSN 1478-6435 R&D Projects: GA ČR GBP108/12/G043; GA MŠk(CZ) LM2011026 Institutional support: RVO:68378271 Keywords : magnesium * ECAP * single crystal * EBSD * recrystallization Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.825, year: 2014

  8. Effect of divalent minerals on the bioaccessibility of pure carotenoids and on physical properties of gastro-intestinal fluids.

    Science.gov (United States)

    Corte-Real, Joana; Iddir, Mohammed; Soukoulis, Christos; Richling, Elke; Hoffmann, Lucien; Bohn, Torsten

    2016-04-15

    During digestion, high concentrations of divalent minerals (DMs) can lead to insoluble lipid-soap complex formation, hampering carotenoid bioaccessibility. The effect of varying concentrations (0-1000 mg/L) of calcium, magnesium, zinc and sodium (control) on the bioaccessibility of lutein, neoxanthin, lycopene and β-carotene, following in vitro gastro-intestinal digestion (GI), was investigated systematically and coupled with physical measurements of the digesta. Addition of DMs significantly decreased (pcalcium. Mean half maximal inhibitory concentrations (EC50) for calcium, magnesium and zinc were 270±18, 253±75 and 420±322 mg/L respectively. Increased DM concentrations correlated with decreased viscosity (r>0.9) and decreased carotenoid bioaccessibility. Surface tension of digesta correlated inversely (p<0.05) with the bioaccessibility of carotenoids. This correlation was mineral and carotenoid dependent. Although based on in vitro findings, it is plausible that similar interactions occur in vivo, with DMs affecting the bioaccessibility and bioavailability of carotenoids and other lipophilic micronutrients and phytochemicals. PMID:26616987

  9. Specific appetite for carotenoids in a colorful bird.

    Directory of Open Access Journals (Sweden)

    Juan Carlos Senar

    Full Text Available BACKGROUND: Since carotenoids have physiological functions necessary for maintaining health, individuals should be selected to actively seek and develop a specific appetite for these compounds. METHODOLOGY/PRINCIPAL FINDINGS: Great tits Parus major in a diet choice experiment, both in captivity and the field, preferred carotenoid-enriched diets to control diets. The food items did not differ in any other aspects measured besides carotenoid content. CONCLUSIONS/SIGNIFICANCE: Specific appetite for carotenoids is here demonstrated for the first time, placing these compounds on a par with essential nutrients as sodium or calcium.

  10. Carboidratos e carotenoides totais em duas variedades de mangarito

    Directory of Open Access Journals (Sweden)

    Ana Paula Sato Ferreira

    2014-05-01

    Full Text Available O objetivo deste trabalho foi avaliar a composição de carboidratos e carotenoides em rizomas mãe e filhos das variedades de mangarito (Xanthosoma riedelianum pequeno e gigante. Amostras dos rizomas coletadas ao longo do ciclo cultural e após 90 dias de armazenamento foram avaliadas quanto aos teores de carboidratos e carotenoides totais. Os rizomas apresentaram aumento no teor de carboidratos, e o rizoma-mãe da variedade pequeno apresentou acréscimos lineares no teor de carotenoides, ao longo do cultivo. O armazenamento reduz os teores de carboidratos e de carotenoides totais em todos os rizomas.

  11. Cyclisation and aromatisation of carotenoids during sediment diagenesis

    OpenAIRE

    Sinninghe Damsté, J. S.; Koster, J; Baas, M.; Koopmans, M.; Kaam-Peters, H.M.E. van; Geenevasen, J.A.J.; Kruk, C.

    1995-01-01

    A novel diaryl isoprenoid with an additional aromatic ring, formed from the diaromatic carotenoid isorenieratene by cyclisation and aromatisation during sediment diagenesis, is identified in carbonaceous sedimentary rocks.

  12. Nitric acid adduct formation during crystallization of barium and strontium nitrates and their co-precipitation from nitric acid media

    International Nuclear Information System (INIS)

    The molar solubilities of Ba, Sr and Pb nitrates in nitric acid as a function of total nitrate concentration is presented and described by the mass action law, indicating on formation of the adducts with nitric acid. Precipitates of Ba(NO3)2 and Sr(NO3)2 crystallized from nitric acid were studied by ISP OES and IR spectroscopy. The data obtained confirmed formation of metastable adducts with nitric acid. IR and X-ray diffraction studies of the mixed salt systems indicated conversion of the mixed salts into (Ba,Sr)(NO3)2 solid solution of discrete structure in range of total nitrate ion concentration ∼6 mol/L. (author)

  13. Carotenoid biosynthetic genes in Brassica rapa: comparative genomic analysis, phylogenetic analysis, and expression profiling

    OpenAIRE

    Li, Peirong; Zhang, Shujiang; Zhang, Shifan; Li, Fei; Zhang, Hui; Cheng, Feng; Wu, Jian; Wang, Xiaowu; Sun, Rifei

    2015-01-01

    Background Carotenoids are isoprenoid compounds synthesized by all photosynthetic organisms. Despite much research on carotenoid biosynthesis in the model plant Arabidopsis thaliana, there is a lack of information on the carotenoid pathway in Brassica rapa. To better understand its carotenoid biosynthetic pathway, we performed a systematic analysis of carotenoid biosynthetic genes at the genome level in B. rapa. Results We identified 67 carotenoid biosynthetic genes in B. rapa, which were ort...

  14. A crystal plasticity model of a formation of a deformation band structure

    Czech Academy of Sciences Publication Activity Database

    Kratochvíl, J.; Kružík, Martin

    2015-01-01

    Roč. 95, č. 32 (2015), s. 3621-3639. ISSN 1478-6435 Grant ostatní: GA ČR(CZ) GAP107/12/0121 Institutional support: RVO:67985556 Keywords : deformation substructure * rigid-plastic crystal plasticity Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.825, year: 2014 http://library.utia.cas.cz/separaty/2015/MTR/kruzik- 0456300.pdf

  15. Identification and Characterization of Genes Involved in Embryonic Crystal Cell Formation During Drosophila Hematopoiesis

    OpenAIRE

    Milchanowski, Allison B.; Henkenius, Amy L.; Narayanan, Maya; Hartenstein, Volker; Banerjee, Utpal

    2004-01-01

    Parallels between vertebrate and Drosophila hematopoiesis add to the value of flies as a model organism to gain insights into blood development. The Drosophila hematopoietic system is composed of at least three classes of terminally differentiated blood cells: plasmatocytes, crystal cells, and lamellocytes. Recent studies have identified transcriptional and signaling pathways in Drosophila involving proteins similar to those seen in human blood development. To identify additional genes involv...

  16. Defect formation in 4H-SiC single crystal grown on the prismatic seeds

    International Nuclear Information System (INIS)

    The defect structure of 4H silicon carbide single crystals grown by PVT method on three prismatic seeds (10-10), (11-20) and (8.3.-11.0) is considered. The only defects existing in the grown ingots are stacking faults and basal plane dislocations. The type of stacking fault is studied. The dependence of stacking fault morphology on the seed orientation is analyzed

  17. Formation and crystallization kinetics of Nd-Fe-B-based bulk amorphous alloy

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Qiong; Ge, Hongliang; Zhang, Pengyue; Li, Dongyun; Wang, Zisheng [China Jiliang University, Magnetism Key Laboratory of Zhejiang Province, Hangzhou (China)

    2014-06-15

    In order to improve the glass-forming ability (GFA) of Nd-Fe-B ternary alloys to obtain fully amorphous bulk Nd-Fe-B-based alloy, the effects of Mo and Y doping on GFA of the alloys were investigated. It was found that the substitution of Mo for Fe and Y for Nd enhanced the GFA of the Nd-Y-Fe-Mo-B alloys. It was also revealed that the GFA of the samples was optimized by 4 at.% Mo doping and increased with theYcontent. The fully amorphous structures were all formed in the Nd{sub 6-x}Y{sub x}Fe{sub 68}Mo{sub 4}B{sub 22} (x =1-5) alloy rods with 1.5 mm-diameter. After subsequent crystallization, the devitrified Nd{sub 3}Y{sub 3}Fe{sub 68}Mo{sub 4}B{sub 22} alloy rod exhibited a uniform distribution of grains with a coercivity of 364.1 kA/m. The crystallization behavior of Nd{sub 3}Y{sub 3}Fe{sub 68}Mo{sub 4}B{sub 22} BMG was investigated in isothermal situation. The Avrami exponent n determined by JAM plot is lower than 2.5, implying that the crystallization is mainly governed by a growth of particles with decreasing nucleation rate. (orig.)

  18. The formation of organic (propolis films)/inorganic (layered crystals) interfaces for optoelectronic applications

    Science.gov (United States)

    Drapak, S. I.; Bakhtinov, A. P.; Gavrylyuk, S. V.; Kovalyuk, Z. D.; Lytvyn, O. S.

    2008-10-01

    Propolis (honeybee glue) organic films were prepared from an alcoholic solution on the surfaces of inorganic layered semiconductors (indium, gallium and bismuth selenides). Atomic force microscopy (AFM) and X-ray diffraction (XRD) are used to characterize structural properties of an organic/inorganic interfaces. It is shown that nanodimensional linear defects and nanodimensional cavities of various shapes are formed on the van der Waals (VDW) surfaces of layered crystals as a result of chemical interaction between the components of propolis (flavonoids, aminoacids and phenolic acids) and the VDW surfaces as well as deformation interaction between the VDW surfaces and propolis films during their polymerization. The nanocavities are formed as a result of the rupture of strong covalent bonds in the upper layers of layered crystals and have the shape of hexagons or triangles in the (0001) plane. The shape, lateral size and distribution of nanodimensional defects on the VDW surfaces depends on the type of crystals, the magnitude and distribution of surface stresses. We have obtained self-organized nanofold structures of propolis/InSe interface. It is established that such heterostructures have photosensitivity in the infrared range hν<1.2 eV (the values of energy gap are 1.2 eV for InSe and 3.07 eV for propolis films at room temperature).

  19. Antioxidant responses and renal crystal formation in rainbow trout treated with melamine administered individually or in combination with cyanuric acid.

    Science.gov (United States)

    Pacini, Nicole; Prearo, Marino; Abete, Maria Cesarina; Brizio, Paola; Dörr, Ambrosius Josef Martin; Reimschuessel, Renate; Andersen, Wendy; Gasco, Laura; Righetti, Marzia; Elia, Antonia Concetta

    2013-01-01

    In 2007 and 2008, renal stone formation and kidney damage in human infants were linked to consumption of melamine (MEL)-contaminated infant formula, as well as renal failure and death in pets due to pet food containing both MEL and cyanuric acid (CYA). The aim of this study was to examine the effects of MEL and CYA administered individually or in combination on concentrations of certain metabolites and enzyme activities that serve as markers for oxidative stress in kidney and liver of rainbow trout. In addition, the levels of muscle MEL and renal crystal formation were determined. Trout were fed MEL and/or CYA for 8 wk at 250, 500, or 1000 mg of each compound/kg in feed. Fish muscle residues of MEL exhibited a dose-response relationship. Coexposure of trout to MEL and CYA at the highest dose led to lower MEL residue concentrations in muscle compared to exposure to MEL alone. Renal MEL-CYA complexes were found in kidneys of fish treated with combined MEL and CYA. A dose response was evident with respect to both (1) number of trout displaying renal crystals and (2) number of crystals per fish. Changes in concentration of antioxidant parameters, such as glutathione, superoxide dismutase, catalase, glutathione peroxidase, and glutathione S-transferase, were recorded in both tissues of MEL- and CYA-dosed trout. Lipid peroxidation was more pronounced in kidney than liver. Therefore, feed contaminated with both MEL and CYA could be problematic for fish, as MEL administered to trout, individually or in combination with CYA, may facilitate the onset of oxidative damage in trout. PMID:23721584

  20. Carotenoids in Staple Cereals: Metabolism, Regulation, and Genetic Manipulation.

    Science.gov (United States)

    Zhai, Shengnan; Xia, Xianchun; He, Zhonghu

    2016-01-01

    Carotenoids play a critical role in animal and human health. Animals and humans are unable to synthesize carotenoids de novo, and therefore rely upon diet as sources of these compounds. However, major staple cereals often contain only small amounts of carotenoids in their grains. Consequently, there is considerable interest in genetic manipulation of carotenoid content in cereal grain. In this review, we focus on carotenoid metabolism and regulation in non-green plant tissues, as well as genetic manipulation in staple cereals such as rice, maize, and wheat. Significant progress has been made in three aspects: (1) seven carotenogenes play vital roles in carotenoid regulation in non-green plant tissues, including 1-deoxyxylulose-5-phosphate synthase influencing isoprenoid precursor supply, phytoene synthase, β-cyclase, and ε-cyclase controlling biosynthesis, 1-hydroxy-2-methyl-2-(E)-butenyl 4-diphosphate reductase and carotenoid cleavage dioxygenases responsible for degradation, and orange gene conditioning sequestration sink; (2) provitamin A-biofortified crops, such as rice and maize, were developed by either metabolic engineering or marker-assisted breeding; (3) quantitative trait loci for carotenoid content on chromosomes 3B, 7A, and 7B were consistently identified, eight carotenogenes including 23 loci were detected, and 10 gene-specific markers for carotenoid accumulation were developed and applied in wheat improvement. A comprehensive and deeper understanding of the regulatory mechanisms of carotenoid metabolism in crops will be beneficial in improving our precision in improving carotenoid contents. Genomic selection and gene editing are emerging as transformative technologies for provitamin A biofortification. PMID:27559339

  1. Carotenoids in Staple Cereals: Metabolism, Regulation, and Genetic Manipulation

    Science.gov (United States)

    Zhai, Shengnan; Xia, Xianchun; He, Zhonghu

    2016-01-01

    Carotenoids play a critical role in animal and human health. Animals and humans are unable to synthesize carotenoids de novo, and therefore rely upon diet as sources of these compounds. However, major staple cereals often contain only small amounts of carotenoids in their grains. Consequently, there is considerable interest in genetic manipulation of carotenoid content in cereal grain. In this review, we focus on carotenoid metabolism and regulation in non-green plant tissues, as well as genetic manipulation in staple cereals such as rice, maize, and wheat. Significant progress has been made in three aspects: (1) seven carotenogenes play vital roles in carotenoid regulation in non-green plant tissues, including 1-deoxyxylulose-5-phosphate synthase influencing isoprenoid precursor supply, phytoene synthase, β-cyclase, and ε-cyclase controlling biosynthesis, 1-hydroxy-2-methyl-2-(E)-butenyl 4-diphosphate reductase and carotenoid cleavage dioxygenases responsible for degradation, and orange gene conditioning sequestration sink; (2) provitamin A-biofortified crops, such as rice and maize, were developed by either metabolic engineering or marker-assisted breeding; (3) quantitative trait loci for carotenoid content on chromosomes 3B, 7A, and 7B were consistently identified, eight carotenogenes including 23 loci were detected, and 10 gene-specific markers for carotenoid accumulation were developed and applied in wheat improvement. A comprehensive and deeper understanding of the regulatory mechanisms of carotenoid metabolism in crops will be beneficial in improving our precision in improving carotenoid contents. Genomic selection and gene editing are emerging as transformative technologies for provitamin A biofortification. PMID:27559339

  2. Effect of carotenoid structure on excited-state dynamics of carbonyl carotenoids

    Czech Academy of Sciences Publication Activity Database

    Chábera, P.; Fuciman, M.; Hříbek, P.; Polívka, Tomáš

    2009-01-01

    Roč. 11, - (2009), s. 8795-8703. ISSN 1463-9076 R&D Projects: GA AV ČR IAA608170604 Institutional research plan: CEZ:AV0Z50510513 Keywords : excited-state dynamics * carbonyl carotenoids * femtosecond spectroscopy Subject RIV: BO - Biophysics Impact factor: 4.116, year: 2009

  3. Formation of H-type liquid crystal dimer at air-water interface

    International Nuclear Information System (INIS)

    We have formed the Langmuir monolayer of H-shaped Azo linked liquid crystal dimer molecule at the air-water interface. Isocycles of the molecule showed hysteresis suggesting the ir-reversible nature of the monolayer formed. The thin film deposited on the silicon wafer was characterized using Atomic Force Microscopy (AFM) and Field Emission Scanning Electron Microscopy (FESEM). The images showed uniform domains of the dimer molecule. We propose that these molecules tend to take book shelf configuration in the liquid phase

  4. Photonic crystal formation on optical nanofibers using femtosecond laser ablation technique

    CERN Document Server

    Nayak, K P

    2012-01-01

    We demonstrate that thousands of periodic nano-craters are fabricated on a subwavelength-diameter tapered optical fiber, an optical nanofiber, by irradiating with just a single femtosecond laser pulse. A key aspect of the fabrication is that the nanofiber itself acts as a cylindrical lens and focuses the femtosecond laser beam on its shadow surface. We also demonstrate that such periodic structures on the nanofiber, act as a 1-D photonic crystal (PhC). Such PhC structures on the nanofiber will strongly enhance the field confinement in such a tapered fiber-based system and may open new avenues in nanophotonics and quantum information technology.

  5. Sequential formation of multiple lattice gap solitons in defocusing photovoltaic-photorefractive crystals

    Science.gov (United States)

    Hui, Juanli; Lu, Keqing; Zhao, Chong; Gao, Lixu; Chen, Weijun

    2016-05-01

    We show that an odd- or even-numbered sequence of multiple gap solitons (MGSs) supported by optical lattices imprinted in defocusing photovoltaic-photorefractive (PP) crystals is possible. The side lobes of MGSs are the small intensity, which can be controlled by changing the propagation constant. The lobes of MGSs are the same intensity except for the side lobes. The existence domain of MGSs decreases with decreasing the lattice depth and vanishes when the lattice depth decreases to below a certain threshold. The stability of MGSs has been investigated numerically and it has been found that they are stable.

  6. Formation of H-type liquid crystal dimer at air-water interface

    Energy Technology Data Exchange (ETDEWEB)

    Karthik, C., E-mail: karthik.c@pilani.bits-pilani.ac.in; Gupta, Adbhut, E-mail: karthik.c@pilani.bits-pilani.ac.in; Joshi, Aditya, E-mail: karthik.c@pilani.bits-pilani.ac.in; Manjuladevi, V., E-mail: karthik.c@pilani.bits-pilani.ac.in; Gupta, Raj Kumar, E-mail: karthik.c@pilani.bits-pilani.ac.in [Department of Physics, Birla Institute of Technology and Science, Pilani, Rajasthan -333031 (India); Varia, Mahesh C.; Kumar, Sandeep [Raman Research Institute, Sadashivanagar, Bangalore - 560080 (India)

    2014-04-24

    We have formed the Langmuir monolayer of H-shaped Azo linked liquid crystal dimer molecule at the air-water interface. Isocycles of the molecule showed hysteresis suggesting the ir-reversible nature of the monolayer formed. The thin film deposited on the silicon wafer was characterized using Atomic Force Microscopy (AFM) and Field Emission Scanning Electron Microscopy (FESEM). The images showed uniform domains of the dimer molecule. We propose that these molecules tend to take book shelf configuration in the liquid phase.

  7. A molecular genetic analysis of carotenoid biosynthesis and the effects of carotenoid mutations on other photosynthetic genes in Rhodobacter capsulatus

    International Nuclear Information System (INIS)

    The nine known R. capsulatus carotenoid genes are contained within the 46 kilobase (kb) photosynthesis gene cluster. An 11 kb subcluster containing eight of these genes has been cloned and its nucleotide sequence determined. A new gene, crtK, has been located in the middle of the subcluster. The carotenoid gene cluster contains sequences homologous to Escherichia coli ω70 promoters, rho-independent transcription terminators, and prokaryotic transcriptional factor binding sites. The phenotypes and genotypes of ten transposon Tn5.7 insertion mutations within the carotenoid gene cluster have been analyzed, by characterization of the carotenoids accumulated and high resolution mapping of the Tn5.7 insertions. The enzymatic blockages in previously uncharacterized early carotenoid mutants have been determined using a new in vitro synthesis system, suggesting specific roles for the CrtB and CrtE gene products. The expression of six of the eight carotenoid genes in the cluster is induced upon the shift from dark chemoheterotrophic to anaerobic photosynthetic growth. The magnitude of the induction is equivalent to that of genes encoding structural photosynthesis polypeptides, although the carotenoid genes are induced earlier after the growth shift. Different means of regulating photosynthesis genes in R. capsulatus are discussed, and a rationale for the temporal pattern of expression of the carotenoid genes during photosynthetic adaptation is presented. Comparison of the deduced amino acid sequences of the two dehydrogenases of the R. capsulatus carotenoid biosynthesis pathway reveals two regions of strong similarity. The effect of carotenoid mutations on the photosynthetic phenotype has been studied by examining growth rates, pigments, pigment-protein complexes and gene expression for a complete set of carotenoid mutants. 161 refs

  8. The effects of dietary carotenoid supplementation and retinal carotenoid accumulation on vision-mediated foraging in the house finch.

    Directory of Open Access Journals (Sweden)

    Matthew B Toomey

    Full Text Available BACKGROUND: For many bird species, vision is the primary sensory modality used to locate and assess food items. The health and spectral sensitivities of the avian visual system are influenced by diet-derived carotenoid pigments that accumulate in the retina. Among wild House Finches (Carpodacus mexicanus, we have found that retinal carotenoid accumulation varies significantly among individuals and is related to dietary carotenoid intake. If diet-induced changes in retinal carotenoid accumulation alter spectral sensitivity, then they have the potential to affect visually mediated foraging performance. METHODOLOGY/PRINCIPAL FINDINGS: In two experiments, we measured foraging performance of house finches with dietarily manipulated retinal carotenoid levels. We tested each bird's ability to extract visually contrasting food items from a matrix of inedible distracters under high-contrast (full and dimmer low-contrast (red-filtered lighting conditions. In experiment one, zeaxanthin-supplemented birds had significantly increased retinal carotenoid levels, but declined in foraging performance in the high-contrast condition relative to astaxanthin-supplemented birds that showed no change in retinal carotenoid accumulation. In experiments one and two combined, we found that retinal carotenoid concentrations predicted relative foraging performance in the low- vs. high-contrast light conditions in a curvilinear pattern. Performance was positively correlated with retinal carotenoid accumulation among birds with low to medium levels of accumulation (∼0.5-1.5 µg/retina, but declined among birds with very high levels (>2.0 µg/retina. CONCLUSION/SIGNIFICANCE: Our results suggest that carotenoid-mediated spectral filtering enhances color discrimination, but that this improvement is traded off against a reduction in sensitivity that can compromise visual discrimination. Thus, retinal carotenoid levels may be optimized to meet the visual demands of specific

  9. A molecular genetic analysis of carotenoid biosynthesis and the effects of carotenoid mutations on other photosynthetic genes in Rhodobacter capsulatus

    Energy Technology Data Exchange (ETDEWEB)

    Armstrong, G.A.

    1989-04-01

    The nine known R. capsulatus carotenoid genes are contained within the 46 kilobase (kb) photosynthesis gene cluster. An 11 kb subcluster containing eight of these genes has been cloned and its nucleotide sequence determined. A new gene, crtK, has been located in the middle of the subcluster. The carotenoid gene cluster contains sequences homologous to Escherichia coli ..omega../sup 70/ promoters, rho-independent transcription terminators, and prokaryotic transcriptional factor binding sites. The phenotypes and genotypes of ten transposon Tn5.7 insertion mutations within the carotenoid gene cluster have been analyzed, by characterization of the carotenoids accumulated and high resolution mapping of the Tn5.7 insertions. The enzymatic blockages in previously uncharacterized early carotenoid mutants have been determined using a new in vitro synthesis system, suggesting specific roles for the CrtB and CrtE gene products. The expression of six of the eight carotenoid genes in the cluster is induced upon the shift from dark chemoheterotrophic to anaerobic photosynthetic growth. The magnitude of the induction is equivalent to that of genes encoding structural photosynthesis polypeptides, although the carotenoid genes are induced earlier after the growth shift. Different means of regulating photosynthesis genes in R. capsulatus are discussed, and a rationale for the temporal pattern of expression of the carotenoid genes during photosynthetic adaptation is presented. Comparison of the deduced amino acid sequences of the two dehydrogenases of the R. capsulatus carotenoid biosynthesis pathway reveals two regions of strong similarity. The effect of carotenoid mutations on the photosynthetic phenotype has been studied by examining growth rates, pigments, pigment-protein complexes and gene expression for a complete set of carotenoid mutants. 161 refs.

  10. Genotype and Environment Effects on Carotenoid Content of Broccoli

    Science.gov (United States)

    Carotenoids are secondary plant metabolites in vegetables reported to confer various positive health-promoting effects when consumed. Brassica oleracea L. vegetables are recognized as excellent sources of dietary carotenoids. Broccoli has emerged as the most important B. oleracea crop in the US an...

  11. Regulatory control of carotenoid accumulation in winter squash during storage

    Science.gov (United States)

    Postharvest storage of fruits and vegetables is often required and frequently results in nutritional quality change. In this study, we investigated carotenoid storage plastids, carotenoid content, and its regulation during 3-month storage of winter squash butternut fruits. We showed that storage imp...

  12. Chemical and Spectroscopic Studies of Carotenoids and Related Compounds

    OpenAIRE

    Lutnæs, Bjart Frode

    2004-01-01

    Structure elucidation of charge delocalised carotenoid mono- and dications by NMR and VIS/NIR spectroscopy. Studies of the nucleophilic reactions of these cations. Studies of the β,β-carotene-iodine complex. Isolation and anmalysis of new carotenoid glucoside esters from extremophilic bacteria.

  13. Optimization of carotenoids extraction from Penaeus semisulcatus shrimp wastes

    Directory of Open Access Journals (Sweden)

    Gholamreza jahed Khaniki

    2013-09-01

    Full Text Available Objective: To find effective method for carotenoids extraction from shrimp waste which is one of the important sources of natural carotenoids and produced in large quantities in Iran. Methods: Two methods of carotenoids extraction, enzymatic and alkaline (NaOH 1 normal treatment, were assayed. About 5 g of gritted shrimp wastes were used at each stage. For alkaline treatment, sodium hydroxide were added to shrimp waste. After 48 h, the mixture was filtered and centrifuged. Results: Alcalase extraction produced (234.00±2.00 mg/L carotenoid and NaOH extraction produced (170.00±1.53 mg/L carotenoid. Based on the samples analyzed, alcalase enzyme showed more efficiency than NaOH extraction to achieve carotenoids from shrimp waste. Conclusions: It can be concluded that using alcalase enzyme for carotenoids extraction can produce higher carotenoids concentration than NaOH extraction method. So alcalase enzyme method can be used for achieving this kind of antioxidant.

  14. Non-invasive in vivo measurement of macular carotenoids

    Science.gov (United States)

    Lambert, James L. (Inventor); Borchert, Mark S. (Inventor)

    2009-01-01

    A non-invasive in vivo method for assessing macular carotenoids includes performing Optical Coherence Tomography (OCT) on a retina of a subject. A spatial representation of carotenoid levels in the macula based on data from the OCT of the retina can be generated.

  15. Manipulation of Carotenoid Content in Plants to Improve Human Health.

    Science.gov (United States)

    Alós, Enriqueta; Rodrigo, Maria Jesús; Zacarias, Lorenzo

    2016-01-01

    Carotenoids are essential components for human nutrition and health, mainly due to their antioxidant and pro-vitamin A activity. Foods with enhanced carotenoid content and composition are essential to ensure carotenoid feasibility in malnourished population of many countries around the world, which is critical to alleviate vitamin A deficiency and other health-related disorders. The pathway of carotenoid biosynthesis is currently well understood, key steps of the pathways in different plant species have been characterized and the corresponding genes identified, as well as other regulatory elements. This enables the manipulation and improvement of carotenoid content and composition in order to control the nutritional value of a number of agronomical important staple crops. Biotechnological and genetic engineering-based strategies to manipulate carotenoid metabolism have been successfully implemented in many crops, with Golden rice as the most relevant example of β-carotene improvement in one of the more widely consumed foods. Conventional breeding strategies have been also adopted in the bio-fortification of carotenoid in staple foods that are highly consumed in developing countries, including maize, cassava and sweet potatoes, to alleviate nutrition-related problems. The objective of the chapter is to summarize major breakthroughs and advances in the enhancement of carotenoid content and composition in agronomical and nutritional important crops, with special emphasis to their potential impact and benefits in human nutrition and health. PMID:27485228

  16. Optimization of carotenoids extraction from Penaeus semisulcatus shrimp wastes

    Institute of Scientific and Technical Information of China (English)

    Gholamreza jahed Khaniki; Parisa Sadighara; Ramin Nabizadeh Nodehi; Mahmood Alimohammadi; Naiema Vakili Saatloo

    2013-01-01

    Objective: To find effective method for carotenoids extraction from shrimp waste which is one of the important sources of natural carotenoids and produced in large quantities in Iran. Methods: Two methods of carotenoids extraction, enzymatic and alkaline (NaOH 1 normal) treatment, were assayed. About 5 g of gritted shrimp wastes were used at each stage. For alkaline treatment, sodium hydroxide were added to shrimp waste. After 48 h, the mixture was filtered and centrifuged.Results:Alcalase extraction produced (234.00±2.00) mg/L carotenoid and NaOH extraction produced (170.00±1.53) mg/L carotenoid. Based on the samples analyzed, alcalase enzyme showed more efficiency than NaOH extraction to achieve carotenoids from shrimp waste.Conclusions:It can be concluded that using alcalase enzyme for carotenoids extraction can produce higher carotenoids concentration than NaOH extraction method. So alcalase enzyme method can be used for achieving this kind of antioxidant.

  17. Gel formation in a mixture of a block copolymer and a nematic liquid crystal.

    Science.gov (United States)

    Khazimullin, Maxim; Müller, Thomas; Messlinger, Stephan; Rehberg, Ingo; Schöpf, Wolfgang; Krekhov, Alexei; Pettau, Robin; Kreger, Klaus; Schmidt, Hans-Werner

    2011-08-01

    The viscoelastic properties of a binary mixture of a mesogenic side-chain block copolymer in a low molecular weight nematic liquid crystal are studied for mass concentrations ranging from the diluted regime up to a liquid crystalline gel state at about 3%. In the gel state, the system does not flow, exhibits a polydomain structure on a microscopic level, and strongly scatters light. Below the gelation point, the system is homogeneous and behaves like a usual nematic, so the continuum theory of liquid crystals can be applied for interpreting the experimental data. Using the dynamic Fréedericksz transition technique, the dependence of the splay elastic constant and the rotational viscosity on the polymer concentration have been obtained. Comparing the dynamic behavior of block copolymer solutions with the respective homopolymer solutions reveals that, above a mass concentration of 1%, self-assembling of the block copolymer chain segments in clusters occurred, resulting in a gel state at higher concentrations. The effective cluster size is estimated as a function of the concentration, and a scaling-law behavior near the sol-gel transition is confirmed. This technique may serve as an alternative method for determining the gelation point. PMID:21929007

  18. Gel formation in a mixture of a block copolymer and a nematic liquid crystal

    Science.gov (United States)

    Khazimullin, Maxim; Müller, Thomas; Messlinger, Stephan; Rehberg, Ingo; Schöpf, Wolfgang; Krekhov, Alexei; Pettau, Robin; Kreger, Klaus; Schmidt, Hans-Werner

    2011-08-01

    The viscoelastic properties of a binary mixture of a mesogenic side-chain block copolymer in a low molecular weight nematic liquid crystal are studied for mass concentrations ranging from the diluted regime up to a liquid crystalline gel state at about 3%. In the gel state, the system does not flow, exhibits a polydomain structure on a microscopic level, and strongly scatters light. Below the gelation point, the system is homogeneous and behaves like a usual nematic, so the continuum theory of liquid crystals can be applied for interpreting the experimental data. Using the dynamic Fréedericksz transition technique, the dependence of the splay elastic constant and the rotational viscosity on the polymer concentration have been obtained. Comparing the dynamic behavior of block copolymer solutions with the respective homopolymer solutions reveals that, above a mass concentration of 1%, self-assembling of the block copolymer chain segments in clusters occurred, resulting in a gel state at higher concentrations. The effective cluster size is estimated as a function of the concentration, and a scaling-law behavior near the sol-gel transition is confirmed. This technique may serve as an alternative method for determining the gelation point.

  19. Importancia nutricional de los pigmentos carotenoides

    OpenAIRE

    Meléndez Martínez, Antonio Jesús; Vicario Romero, Isabel; Heredia Mira, Francisco José

    2004-01-01

    Los pigmentos carotenoides son compuestos responsables de la coloración de gran número de alimentos vegetales y animales, como zanahorias, zumo de naranja, tomates, salmón y yema del huevo. Desde hace muchos años, se sabe que algunos de estos compuestos, como a y b-caroteno, así como la b-criptoxantina, son provitaminas A. No obstante, estudios recientes han puesto de manifiesto las propiedades antioxidantes de estos pigmentos, así como su eficacia en la prevención de ciertas enfermedades del...

  20. Carotenoids and health signalling in animals

    Czech Academy of Sciences Publication Activity Database

    Vinkler, Michal; Svobodová, J.; Maršík, Petr; Albrecht, Tomáš

    Hauppauge : Nova Science Publishers, 2011 - (Yamaguchi, M.), s. 189-234 ISBN 978-1-61209-713-8 R&D Projects: GA ČR GA206/08/1281; GA ČR GA206/08/0640; GA ČR GAP505/10/1871; GA MŠk LC06073 Institutional research plan: CEZ:AV0Z60930519; CEZ:AV0Z50380511 Keywords : carotenoids * condition * diseases * health * ornamentation * oxidative stress * parasites * sexual signalling Subject RIV: EG - Zoology https://www.novapublishers.com/catalog/product_info.php?products_id=22091

  1. The intake of carotenoids in Denmark

    DEFF Research Database (Denmark)

    Leth, Torben; Jakobsen, Jette; Andersen, N. L.

    2000-01-01

    To estimate the intake of carotenoids in the Danish population Danish fruits and vegetables were screened with an HPLC method consisting of extraction with ethanol:tetrahydrofuran, separation by reversed phase HPLC with the mobile phase acetonitril:methanol:dichlormethan, triethylamin, BHT and...... detection at 450 nm. Food intakes were estimated by the national dietary surveys (1995) from 7 days' food registration (n = 1837 adults), which allows the whole diet to be described by the mean intake and intake distribution of 207 raw or semiprepared foods. By multiplication with the mean content in the...

  2. Formation and growth of crystal defects in directionally solidified multicrystalline silicon for solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Ryningen, Birgit

    2008-07-01

    Included in this thesis are five publications and one report. The common theme is characterisation of directionally solidified multicrystalline silicon for solar cells. Material characterisation of solar cell silicon is naturally closely linked to both the casting process and to the solar cell processing: Many of the material properties are determined by the casting process, and the solar cell processing will to some extend determine which properties will influence the solar cell performance. Solar grade silicon (SoG-Si) made by metallurgical refining route and supplied by Elkem Solar was directionally solidified and subsequently characterised, and a simple solar cell process was applied. Except from some metallic co-precipitates in the top of the ingot, no abnormalities were found, and it is suggested that within the limits of the tests performed in this thesis, the casting and the solar cell processing, rather than the assumed higher impurity content, was the limiting factor. It is suggested in this thesis that the main quality problem in multicrystalline silicon wafers is the existence of dislocation clusters covering large wafer areas. The clusters will reduce the effect of gettering and even if gettering could be performed successfully, the clusters will still reduce the minority carrier mobility and hence the solar cell performance. It has further been pointed out that ingots solidified under seemingly equal conditions might have a pronounced difference in minority carrier lifetime. Ingots with low minority carrier lifetime have high dislocation densities. The ingots with the substantially higher lifetime seem all to be dominated by twins. It is also found a link between a higher undercooling and the ingots dominated by twins. It is suggested that the two types of ingots are subject to different nucleation and crystal growth mechanisms: For the ingots dominated by dislocations, which are over represented, the crystal growth is randomly nucleated at the

  3. Poly-β-hydroxybutyrate Metabolism Is Unrelated to the Sporulation and Parasporal Crystal Protein Formation in Bacillus thuringiensis

    Science.gov (United States)

    Wang, Xun; Li, Zhou; Li, Xin; Qian, Hongliang; Cai, Xia; Li, Xinfeng; He, Jin

    2016-01-01

    Poly-3-hydroxybutyrate (PHB) is a natural polymer synthesized by many bacteria as a carbon-energy storage material. It was accumulated maximally prior to the spore formation but was degraded during the process of sporulation in Bacillus thuringiensis. Intriguingly, B. thuringiensis also accumulates large amounts of insecticidal crystal proteins (ICPs) during sporulation, which requires considerable input of carbon and energy sources. How PHB accumulation affects sporulation and ICP formation remains unclear to date. Intuitively, one would imagine that accumulated PHB provides the energy required for ICP formation. Yet our current data indicate that this is not the case. First, growth curves of the deletion mutants of phaC (encoding the PHB synthase) and phaZ (encoding the PHB depolymerase) were found to be similar to the parent strain BMB171; no difference in growth rate could be observed. In addition we further constructed the cry1Ac10 ICP gene overexpression strains of BMB171 (BMB171-cry), as well as its phaC and phaZ deletion mutants ΔphaC-cry and ΔphaZ-cry to compare their spore and ICP production rates. Again, not much change of ICP production was observed among these strains either. In fact, PHB was still degraded in most ΔphaZ-cry cells as observed by transmission electron microscopy. Together these results indicated that there is no direct association between the PHB accumulation and the sporulation and ICP formation in B. thuringiensis. Some other enzymes for PHB degradation or other energy source may be responsible for the sporulation and/or ICP formation in B. thuringiensis. PMID:27379025

  4. Poly-β-hydroxybutyrate Metabolism Is Unrelated to the Sporulation and Parasporal Crystal Protein Formation in Bacillus thuringiensis.

    Science.gov (United States)

    Wang, Xun; Li, Zhou; Li, Xin; Qian, Hongliang; Cai, Xia; Li, Xinfeng; He, Jin

    2016-01-01

    Poly-3-hydroxybutyrate (PHB) is a natural polymer synthesized by many bacteria as a carbon-energy storage material. It was accumulated maximally prior to the spore formation but was degraded during the process of sporulation in Bacillus thuringiensis. Intriguingly, B. thuringiensis also accumulates large amounts of insecticidal crystal proteins (ICPs) during sporulation, which requires considerable input of carbon and energy sources. How PHB accumulation affects sporulation and ICP formation remains unclear to date. Intuitively, one would imagine that accumulated PHB provides the energy required for ICP formation. Yet our current data indicate that this is not the case. First, growth curves of the deletion mutants of phaC (encoding the PHB synthase) and phaZ (encoding the PHB depolymerase) were found to be similar to the parent strain BMB171; no difference in growth rate could be observed. In addition we further constructed the cry1Ac10 ICP gene overexpression strains of BMB171 (BMB171-cry), as well as its phaC and phaZ deletion mutants ΔphaC-cry and ΔphaZ-cry to compare their spore and ICP production rates. Again, not much change of ICP production was observed among these strains either. In fact, PHB was still degraded in most ΔphaZ-cry cells as observed by transmission electron microscopy. Together these results indicated that there is no direct association between the PHB accumulation and the sporulation and ICP formation in B. thuringiensis. Some other enzymes for PHB degradation or other energy source may be responsible for the sporulation and/or ICP formation in B. thuringiensis. PMID:27379025

  5. Carotenoids and Their Isomers: Color Pigments in Fruits and Vegetables

    Directory of Open Access Journals (Sweden)

    Yueming Jiang

    2011-02-01

    Full Text Available Fruits and vegetables are colorful pigment-containing food sources. Owing to their nutritional benefits and phytochemicals, they are considered as ‘functional food ingredients’. Carotenoids are some of the most vital colored phytochemicals, occurring as all-trans and cis-isomers, and accounting for the brilliant colors of a variety of fruits and vegetables. Carotenoids extensively studied in this regard include β-carotene, lycopene, lutein and zeaxanthin. Coloration of fruits and vegetables depends on their growth maturity, concentration of carotenoid isomers, and food processing methods. This article focuses more on several carotenoids and their isomers present in different fruits and vegetables along with their concentrations. Carotenoids and their geometric isomers also play an important role in protecting cells from oxidation and cellular damages.

  6. Carotenoids in Marine Invertebrates Living along the Kuroshio Current Coast

    Directory of Open Access Journals (Sweden)

    Yoshikazu Sakagami

    2011-08-01

    Full Text Available Carotenoids of the corals Acropora japonica, A. secale, and A. hyacinthus, the tridacnid clam Tridacna squamosa, the crown-of-thorns starfish Acanthaster planci, and the small sea snail Drupella fragum were investigated. The corals and the tridacnid clam are filter feeders and are associated with symbiotic zooxanthellae. Peridinin and pyrrhoxanthin, which originated from symbiotic zooxanthellae, were found to be major carotenoids in corals and the tridacnid clam. The crown-of-thorns starfish and the sea snail D. fragum are carnivorous and mainly feed on corals. Peridinin-3-acyl esters were major carotenoids in the sea snail D. fragum. On the other hand, ketocarotenoids such as 7,8-didehydroastaxanthin and astaxanthin were major carotenoids in the crown-of-thorns starfish. Carotenoids found in these marine animals closely reflected not only their metabolism but also their food chains.

  7. Biosynthesis of Carotenoids in Plants: Enzymes and Color.

    Science.gov (United States)

    Rosas-Saavedra, Carolina; Stange, Claudia

    2016-01-01

    Carotenoids are the most important biocolor isoprenoids responsible for yellow, orange and red colors found in nature. In plants, they are synthesized in plastids of photosynthetic and sink organs and are essential molecules for photosynthesis, photo-oxidative damage protection and phytohormone synthesis. Carotenoids also play important roles in human health and nutrition acting as vitamin A precursors and antioxidants. Biochemical and biophysical approaches in different plants models have provided significant advances in understanding the structural and functional roles of carotenoids in plants as well as the key points of regulation in their biosynthesis. To date, different plant models have been used to characterize the key genes and their regulation, which has increased the knowledge of the carotenoid metabolic pathway in plants. In this chapter a description of each step in the carotenoid synthesis pathway is presented and discussed. PMID:27485218

  8. Metabolism of carotenoids and apocarotenoids during ripening of raspberry fruit

    DEFF Research Database (Denmark)

    Beekwilder, J; van der Meer, IM; Simicb, A;

    2008-01-01

    Carotenoids are important lipophilic antioxidants in fruits. Apocarotenoids such as α-ionone and β-ionone, which are breakdown products of carotenoids, are important for the flavor characteristics of raspberry fruit, and have also been suggested to have beneficial effects on human health. Raspberry...... is one of the few fruits where fruit ripening is accompanied by the massive production of apocarotenoids. In this paper, changes in levels of carotenoids and apocarotenoids during raspberry fruit ripening are described. In addition, the isolation and characterization of a gene encoding a carotenoid...... cleavage dioxygenase (CCD), which putatively mediates the degradation of carotenoids to apocarotenoids during raspberry fruit ripening, is reported. Such information helps us to better understand how these compounds are produced in plants and may also enable us to develop novel strategies for improved...

  9. Variation in Content of Carotenoids and Vitamin C in Carrots

    Directory of Open Access Journals (Sweden)

    Jana MATĚJKOVÁ

    2010-12-01

    Full Text Available Carrots are the most popular and wide-spread of all root vegetables, and are the principal source of carotenoids in human diet. The purpose of this study was to examine differences between cultivars and the effect of storage regarding the carotenoid and vitamin C content in carrots. Six carrot cultivars were used in this study, ranging from early to late ones. Observed carotenoid content ranged from 60 mg kg-1 to 134 mg kg-1. Significantly higher levels of carotenoids were found in late and moderately late cultivars in comparison to early ones. Vitamin C content in these cultivars ranged from 54 mg kg-1 to 132 mg kg-1. Significantly higher contents of vitamin C were also found in the late cultivars. 30-day storage resulted in a significant reduction in vitamin C content, on average of 47%. There was also a reduction in the carotenoids content, but to a lesser extent, on average of 11%.

  10. Adsorption, Desorption, Surface Diffusion, Lattice Defect Formation, and Kink Incorporation Processes of Particles on Growth Interfaces of Colloidal Crystals with Attractive Interactions

    OpenAIRE

    Yoshihisa Suzuki; Yoshiaki Hattori; Jun Nozawa; Satoshi Uda; Akiko Toyotama; Junpei Yamanaka

    2016-01-01

    Good model systems are required in order to understand crystal growth processes because, in many cases, precise incorporation processes of atoms or molecules cannot be visualized easily at the atomic or molecular level. Using a transmission-type optical microscope, we have successfully observed in situ adsorption, desorption, surface diffusion, lattice defect formation, and kink incorporation of particles on growth interfaces of colloidal crystals of polystyrene particles in aqueous sodium po...

  11. Creep substructure formation in sodium chloride single crystals in the power law and exponential creep regimes

    Science.gov (United States)

    Raj, S. V.; Pharr, G. M.

    1989-01-01

    Creep tests conducted on NaCl single crystals in the temperature range from 373 to 1023 K show that true steady state creep is obtained only above 873 K when the ratio of the applied stress to the shear modulus is less than or equal to 0.0001. Under other stress and temperature conditions, corresponding to both power law and exponential creep, the creep rate decreases monotonically with increasing strain. The transition from power law to exponential creep is shown to be associated with increases in the dislocation density, the cell boundary width, and the aspect ratio of the subgrains along the primary slip planes. The relation between dislocation structure and creep behavior is also assessed.

  12. Crystallization and Glass Formation in Liquid pd0.45Ni0.55

    International Nuclear Information System (INIS)

    Constant temperature-constant pressure (TPN) and constant temperature-constant volume (TVN) dynamics simulations are performed to investigate the glass-forming ability of the eutectic composition of Pd-Ni system under rapid quenching from the liquid state. We use the quantum Sutton-Chen many body potentials for Pd and Ni to examine Pd-Ni alloy. Liquid Pd0.45Ni0.55 becomes glass at the fast and intermediate cooling rates, while it forms a face-centered-cubic (fcc) crystal at the slow cooling rate. The relation between the cooling rates and glass transition temperatures is revealed. The results of the simulation also indicate that the diffusion coefficients of the system decrease rapidly with decreasing temperature above their glass transition temperatures. The viscosity values calculated for the liquid and supercooled region shows that Pd0.45Ni0.55 is a strong liquid

  13. AOT-microemulsions-based formation and evolution of PbWO$_{4}$ crystals

    CERN Document Server

    Chen, D; Tang Kai Bin; Liang Zhen Hua; Zheng Hua Gui

    2004-01-01

    Anionic surfactant-AOT-microemulsions-assisted formation and evolution of PbWO//4 nanostructures with bundles rodlike, ellipsoidlike, and spherelike prepared at different media conditions were studied by powder X-ray diffraction pattern, field emission scanning electron microscopy, and transmission electron microscopy. The possible mechanisms for the formation of PbWO//4 samples in series of microemulsion systems were discussed. Various comparison experiments show that several experimental parameters, such as the AOT concentration, the water content, and reaction temperature play important roles in the morphological control of PbWO//4 nanostructures. Room-temperature photoluminescence of PbWO//4 samples with different morphologies has also been investigated and the results reveal that all these samples showed similar features with emissions at 480 similar to 510 nm but different luminescence intensity. 40 Refs.

  14. Formation of color centers in CdF/sub 2/ crystals irradiated by gamma rays

    Energy Technology Data Exchange (ETDEWEB)

    Kaipov, B.; Tavshunskii, G.A.; Gapparov, N.

    1975-01-01

    After irradiation in liquid nitrogen, an ultraviolet absorption band in the region of 350 nm was induced in all samples. This band is maintained during annealing of thermoemission peaks below 170/sup 0/K. On annealing above this temperature the absorption band at 350 nm vanished, and the EPR signal with g = 2.014 induced by the gamma irradiation at 77/sup 0/K vanished at the same time. This behavior is attributed to the formation of localized holes by the gamma irradiation. (SJR)

  15. Engineering the crystal growth behavior: 'On substrate' MOD formation of ZnO hollow spheres

    International Nuclear Information System (INIS)

    In this paper is described an easy, one-pot synthesis of ZnO hollow spheres with sizes ranging from 300 nm to 500 nm, by spin-coating deposition on aluminum substrate. Simplified models explaining the shape formation based on film-substrate interaction are discussed. The characteristic size and shape of the nanostructures obtained by the described method and the properties of ZnO as a low-cost biocompatible material make this methodology of synthesis interesting for a wide range of applications including optoelectronics, catalysis and (bio)sensors.

  16. Nonlocal photopolymerization effect in the formation of reflective holographic polymer-dispersed liquid crystals

    International Nuclear Information System (INIS)

    The optical performance of reflective holographic polymer-dispersed liquid crystals (H-PDLCs) is investigated as a function of sample thickness and laser exposure intensity, and, the data are analyzed in terms of a nonlocal photopolymerization model. The intensity of laser exposure is proven to have a strong influence on the reflection efficiency of H-PDLCs. We have found that the experimental results cannot be completely interpreted by the previous local diffusion model. Combined with transfer matrix analysis, a modified diffusion model with a nonlocal photopolymerization term is proposed herein, which qualitatively describes our experimental observations. The experimental data demonstrates our assertion that the nonlocal effect is strongly correlated to the exposure conditions. Under the low exposure condition, the diffusion effect is screened by this nonlocal effect, and effectively a small diffusion constant is observed. Under the high exposure condition, the nonlocal effect can be suppressed and the modified diffusion model can be deduced to the original local diffusion model. Also, within the framework of this nonlocal model, overexposure can be properly explained

  17. Monocyclic β-lactam and unexpected oxazinone formation: synthesis, crystal structure, docking studies and antibacterial evaluation.

    Science.gov (United States)

    Aneja, Babita; Irfan, Mohammad; Hassan, Md Imtaiyaz; Prakash, Amresh; Yadava, Umesh; Daniliuc, Constantin G; Zafaryab, Md; Rizvi, M Moshahid A; Azam, Amir; Abid, Mohammad

    2016-10-01

    Novel monocyclic β-lactam derivatives bearing aryl, phenyl and heterocyclic rings were synthesized as possible antibacterial agents. Cyclization of imines (3h, 3t) with phenylacetic acid in the presence of phosphoryl chloride and triethyl amine did not afford the expected β-lactams. Instead, highly substituted 1,3-oxazin-4-ones (4h, 4t) were isolated as the only product and confirmed by single crystal X-ray analysis of 4t. The results of antibacterial activity showed that compound 4l exhibited considerable antibacterial activity with MIC and MBC values of 62.5 µg/mL against Klebsiella pneumoniae. Cytotoxicity assay on Chinese Hamster Ovary (CHO) cell line revealed non-cytotoxic behavior of compounds 4d, 4h, 4k and 4l up to 200 μg/mL conc. Molecular docking was performed for compound 4l with penicillin binding protein-5 to identify the nature of interactions. The results of both in silico and in vitro evaluation provide the basis for compound 4l to be carried as a potential lead molecule in the drug discovery pipeline against bacterial infections. PMID:26133357

  18. Peroxyl radical reactions with carotenoids in microemulsions: Influence of microemulsion composition and the nature of peroxyl radical precursor.

    Science.gov (United States)

    El-Agamey, Ali; McGarvey, David J

    2016-01-01

    The reactions of acetylperoxyl radicals with different carotenoids (7,7'-dihydro-β-carotene and ζ-carotene) in SDS and CTAC microemulsions of different compositions were investigated using laser flash photolysis (LFP) coupled with kinetic absorption spectroscopy. The primary objective of this study was to explore the influence of microemulsion composition and the type of surfactant used on the yields and kinetics of various transients formed from the reaction of acetylperoxyl radicals with carotenoids. Also, the influence of the site (hydrocarbon phases or aqueous phase) of generation of the peroxyl radical precursor was examined by using 4-acetyl-4-phenylpiperidine hydrochloride (APPHCl) and 1,1-diphenylacetone (11DPA) as water-soluble and lipid-soluble peroxyl radical precursors, respectively. LFP of peroxyl radical precursors with 7,7'-dihydro-β-carotene (77DH) in different microemulsions gives rise to the formation of three distinct transients namely addition radical (λmax=460 nm), near infrared transient1 (NIR, λmax=700 nm) and 7,7'-dihydro-β-carotene radical cation (77DH(•+), λmax=770 nm). In addition, for ζ-carotene (ZETA) two transients (near infrared transient1 (NIR1, λmax=660 nm) and ζ-carotene radical cation (ZETA(•+), λmax=730-740 nm)) are generated following LFP of peroxyl radical precursors in the presence of ζ-carotene (ZETA) in different microemulsions. The results show that the composition of the microemulsion strongly influences the observed yield and kinetics of the transients formed from the reactions of peroxyl radicals (acetylperoxyl radicals) with carotenoids (77DH and ZETA). Also, the type of surfactant used in the microemulsions influences the yield of the transients formed. The dependence of the transient yields and kinetics on microemulsion composition (or the type of surfactant used in the microemulsion) can be attributed to the change of the polarity of the microenvironment of the carotenoid. Furthermore, the nature of

  19. Excited State Structural Dynamics of Carotenoids and ChargeTransfer Systems

    Energy Technology Data Exchange (ETDEWEB)

    Van Tassle, Aaron Justin

    2006-09-01

    This dissertation describes the development andimplementation of a visible/near infrared pump/mid-infrared probeapparatus. Chapter 1 describes the background and motivation ofinvestigating optically induced structural dynamics, paying specificattention to solvation and the excitation selection rules of highlysymmetric molecules such as carotenoids. Chapter 2 describes thedevelopment and construction of the experimental apparatus usedthroughout the remainder of this dissertation. Chapter 3 will discuss theinvestigation of DCM, a laser dye with a fluorescence signal resultingfrom a charge transfer state. By studying the dynamics of DCM and of itsmethyl deuterated isotopomer (an otherwise identical molecule), we areable to investigate the origins of the charge transfer state and provideevidence that it is of the controversial twisted intramolecular (TICT)type. Chapter 4 introduces the use of two-photon excitation to the S1state, combined with one-photon excitation to the S2 state of thecarotenoid beta-apo-8'-carotenal. These 2 investigations show evidencefor the formation of solitons, previously unobserved in molecular systemsand found only in conducting polymers Chapter 5 presents an investigationof the excited state dynamics of peridinin, the carotenoid responsiblefor the light harvesting of dinoflagellates. This investigation allowsfor a more detailed understanding of the importance of structuraldynamics of carotenoids in light harvesting.

  20. Intraspecific Variation in Carotenoids of Brassica oleracea var. sabellica.

    Science.gov (United States)

    Mageney, Vera; Baldermann, Susanne; Albach, Dirk C

    2016-04-27

    Carotenoids are best known as a source of natural antioxidants. Physiologically, carotenoids are part of the photoprotection in plants as they act as scavengers of reactive oxygen species (ROS). An important source of carotenoids in European food is Brassica oleracea. Focusing on the most abundant carotenoids, we estimated the contents of ß-carotene, (9Z)-neoxanthin, zeaxanthin, and lutein as well as those of chlorophylls a and b to assess their variability in Brassica oleracea var. sabellica. Our analyses included more than 30 cultivars categorized in five distinct sets grouped according to morphological characteristics or geographical origin. Our results demonstrated specific carotenoid patterns characteristic for American, Italian, and red-colored kale cultivars. Moreover, we demonstrated a tendency of high zeaxanthin proportions under traditional harvest conditions, which accord to low-temperature regimes. We also compared the carotenoid patterns of self-generated hybrid lines. Corresponding findings indicated that crossbreeding has a high potential for carotenoid content optimization in kale. PMID:27045759

  1. Raman measurement of carotenoid composition in human skin

    Science.gov (United States)

    Ermakov, Igor V.; Ermakova, Maia R.; Gellermann, Werner

    2004-07-01

    The carotenoids lycopene and beta-carotene are powerful antioxidants in skin and are thought to act as scavengers for free radicals and singlet oxygen. The role of carotenoid species in skin health is of strong current interest. We demonstrate the possibility to use Resonance Raman spectroscopy for fast, non-invasive, highly specific, and quantitative detection of beta-carotene and lycopene in human skin. Analyzing Raman signals originating from the carbon-carbon double bond stretch vibrations of the carotenoid molecules under blue and green laser excitation, we were able to characterize quantitatively the relative concentrations of each carotenoid species in-vivo. In the selective detection, we take advantage of different Raman cross-section spectral profiles for beta-carotene and lycopene molecules, and obtain a quantitative assessment of individual long-chain carotenoid species in the skin rather than their cumulative levels. Preliminary dual-wavelength Raman measurements reveal significant differences in the carotenoid composition of different subjects. The technique holds promise for rapid screening of carotenoid compositions in human skin in large populations and may be suitable in clinical studies for assessing the risk for cutaneous diseases.

  2. A complex carotenoid palette tunes avian colour vision.

    Science.gov (United States)

    Toomey, Matthew B; Collins, Aaron M; Frederiksen, Rikard; Cornwall, M Carter; Timlin, Jerilyn A; Corbo, Joseph C

    2015-10-01

    The brilliantly coloured cone oil droplets of the avian retina function as long-pass cut-off filters that tune the spectral sensitivity of the photoreceptors and are hypothesized to enhance colour discrimination and improve colour constancy. Although it has long been known that these droplets are pigmented with carotenoids, their precise composition has remained uncertain owing to the technical challenges of measuring these very small, dense and highly refractile optical organelles. In this study, we integrated results from high-performance liquid chromatography, hyperspectral microscopy and microspectrophotometry to obtain a comprehensive understanding of oil droplet carotenoid pigmentation in the chicken (Gallus gallus). We find that each of the four carotenoid-containing droplet types consists of a complex mixture of carotenoids, with a single predominant carotenoid determining the wavelength of the spectral filtering cut-off. Consistent with previous reports, we find that the predominant carotenoid type in the oil droplets of long-wavelength-sensitive, medium-wavelength-sensitive and short-wavelength-sensitive type 2 cones are astaxanthin, zeaxanthin and galloxanthin, respectively. In addition, the oil droplet of the principal member of the double cone contains a mixture of galloxanthin and two hydroxycarotenoids (lutein and zeaxanthin). Short-wavelength-absorbing apocarotenoids are present in all of the droplet types, providing filtering of light in a region of the spectrum where filtering by hydroxy- and ketocarotenoids may be incomplete. Thus, birds rely on a complex palette of carotenoid pigments within their cone oil droplets to achieve finely tuned spectral filtering. PMID:26446559

  3. The carotenoid biosynthetic pathway: thinking in all dimensions.

    Science.gov (United States)

    Shumskaya, Maria; Wurtzel, Eleanore T

    2013-07-01

    The carotenoid biosynthetic pathway serves manifold roles in plants related to photosynthesis, photoprotection, development, stress hormones, and various volatiles and signaling apocarotenoids. The pathway also produces compounds that impact human nutrition and metabolic products that contribute to fragrance and flavor of food and non-food crops. It is no surprise that the pathway has been a target of metabolic engineering, most prominently in the case of Golden Rice. The future success and predictability of metabolic engineering of carotenoids rests in the ability to target carotenoids for specific physiological purposes as well as to simultaneously modify carotenoids along with other desired traits. Here, we ask whether predictive metabolic engineering of the carotenoid pathway is indeed possible. Despite a long history of research on the pathway, at this point in time we can only describe the pathway as a parts list and have almost no knowledge of the location of the complete pathway, how it is assembled, and whether there exists any trafficking of the enzymes or the carotenoids themselves. We discuss the current state of knowledge regarding the "complete" pathway and make the argument that predictive metabolic engineering of the carotenoid pathway (and other pathways) will require investigation of the three dimensional state of the pathway as it may exist in plastids of different ultrastructures. Along with this message we point out the need to develop new types of visualization tools and resources that better reflect the dynamic nature of biosynthetic pathways. PMID:23683930

  4. The Capability of Rhodotorula slooffiae to Produce Carotenoid

    Directory of Open Access Journals (Sweden)

    Farzaneh Sadat Naghavi

    2015-02-01

    Full Text Available Background: Rhodotorula is characterized by the absence of ballistoconidia, fermentation ability, and starch-like compounds. Biology of the species is not well-identified; therefore molecular identification is required. Sequence analysis of the D1/D2 region can be used for the identification of the majority of Basidiomycetous species. Carotenoids which are natural pigments can be synthesized by some genera of yeasts such as Rhodotorula. The increase of demand for carotenoids obtained from natural sources has promoted major efforts to recognize potential microbial sources. The aims of this study were to identify a strain isolated from leather wastewater and to investigate its carotenoid production ability. The effect of 2 different medium (Semi-synthetic medium (MMS and yeast malt extract medium (YM on biomass and carotenoid production was studied. Materials and Methods: In this experimental study, sequence analysis of the D1/D2 region in addition to morphological and biochemical characterization to identify the strain was carried out. To isolate the carotenoid pigment, cells were suspended in acetone and broken using a homogenizer, followed by centrifugation and supernatant was separated; thus pigments were measured spectrophotometrically at 450 nM using the extinction coefficient E1%450=2500. Results: Identification processes represented strain SG006 as a Rhodotorula slooffiae. The sequence was deposited in the Gene Bank database with accession number JX997835. The results showed that SG006 are able to produce carotenoid and MMS medium promoted carotenoid production. Conclusion: We found that Rhodotorula slooffiae showed the ability to produce carotenoid. However, further work is needed to optimize of the amount of product and to characterize the carotenoids.

  5. Carotenoid maintenance handicap and the physiology of carotenoid-based signalisation of health

    Czech Academy of Sciences Publication Activity Database

    Vinkler, Michal; Albrecht, Tomáš

    2010-01-01

    Roč. 97, č. 1 (2010), s. 19-28. ISSN 0028-1042 R&D Projects: GA ČR GA206/06/0851; GA MŠk LC06073; GA ČR GA206/08/1281 Institutional research plan: CEZ:AV0Z60930519 Keywords : Carotenoids * Ornamentation * Oxidative stress * Testosterone * Trade-off Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 2.250, year: 2010

  6. Synthetic Biology and Metabolic Engineering for Marine Carotenoids: New Opportunities and Future Prospects

    OpenAIRE

    Chonglong Wang; Jung-Hun Kim; Seon-Won Kim

    2014-01-01

    Carotenoids are a class of diverse pigments with important biological roles such as light capture and antioxidative activities. Many novel carotenoids have been isolated from marine organisms to date and have shown various utilizations as nutraceuticals and pharmaceuticals. In this review, we summarize the pathways and enzymes of carotenoid synthesis and discuss various modifications of marine carotenoids. The advances in metabolic engineering and synthetic biology for carotenoid production ...

  7. Potential implications for epigenetic regulation of carotenoid biosynthesis during root and shoot development

    OpenAIRE

    Cazzonelli, Christopher Ian; Yin, Kuide; Pogson, Barry J.

    2009-01-01

    Major regulators of carotenoid biosynthesis have remained rather elusive even though the flux through the branch in the carotenoid pathway can affect plant development in response to environmental stimuli, such as light. Our recent investigations demonstrated that the production of the most abundant carotenoid in plants, lutein, is regulated by carotenoid isomerase (CRTISO) activity at a rate-limiting step of this branch point in carotenoid biosynthesis. CRTISO is required to isomerase cis-ca...

  8. Single-crystal star-like arrayed particles of hematite: Synthesis, formation mechanism and magnetic properties

    International Nuclear Information System (INIS)

    Using urea as a precipitation agent, star-like arrayed hematite (α-Fe2O3) particles were prepared by a facile precipitation-oxidation reaction in an aqueous solution containing ceyltrimethylammonium bromide at 80 deg. C. The particles were characterized by powder X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM) and selected-area electron diffraction (SAED). Reaction temperature and urea amount are found to affect significantly the morphology and phase composition of the products. The formation mechanism of star-like arrayed α-Fe2O3 particles is proposed to be oriented attachment combining epitaxial overgrowth. The star-like arrayed α-Fe2O3 particles show a weak ferromagnetic behavior with a remanent magnetization of 5.69 x 10-1 emu g-1 and a coercivity of 156.08 Oe at room temperature.

  9. Basic building units, self-assembly and crystallization in the formation of complex inorganic open architectures

    Indian Academy of Sciences (India)

    C N R Rao

    2001-10-01

    Careful investigations of open-framework metal phosphates reveal that the formation of these complex architectures is likely to involve a process wherein one-dimensional ladders or chains, and possibly zero-dimens ional monomers, transform to higher dimensional structures. The one-dimensional ladder appears to be the primary building unit of these structures. At one stage of the building-up process, spontaneous self-assembly of a low-dimensional structure such as the ladder seems to occur, followed by crys tallization of a two- or three-dimensional structure. Accordingly, many of the higher dimensional structures retain the structural features of the 1D structure, indicating the occurrence of self-assembly. These findings mark the beginnings of our understan ding of complex supramolecular inorganic materials.

  10. Carboidratos e carotenoides totais em duas variedades de mangarito

    OpenAIRE

    Ana Paula Sato Ferreira; Mário Puiatti; Ariana Mota Pereira; Paulo Roberto Cecon; Aline da Silva Bhering; Teresa Drummond Correia Mendes

    2014-01-01

    O objetivo deste trabalho foi avaliar a composição de carboidratos e carotenoides em rizomas mãe e filhos das variedades de mangarito (Xanthosoma riedelianum) pequeno e gigante. Amostras dos rizomas coletadas ao longo do ciclo cultural e após 90 dias de armazenamento foram avaliadas quanto aos teores de carboidratos e carotenoides totais. Os rizomas apresentaram aumento no teor de carboidratos, e o rizoma-mãe da variedade pequeno apresentou acréscimos lineares no teor de carotenoides, ao long...

  11. Cloning and Characterization of a Lycium chinense Carotenoid Isomerase Gene Enhancing Carotenoid Accumulation in Transgenic Tobacco

    Institute of Scientific and Technical Information of China (English)

    李招娣; 季静; 王罡

    2015-01-01

    Carotenoid isomerase(CRTISO)is a key enzyme that catalyzes the conversion of cis-lycopene to all-trans lycopene. In this study, we isolated and characterized the CRTISO gene from Lycium chinense (LcCRTISO) for the first time. The open reading frame of LcCRTISO was 1 815 bp encoding a protein of 604 amino acids with a molecular mass of 66.24 kDa. Amino acid sequence analysis revealed that the LcCRTISO had a high level of simi-larity to other CRTISO. Phylogenetic analysis displayed that LcCRTISO kept a closer relationship with the CRTISO of plants than with those of other species. Semi-quantitative PCR analysis indicated that LcCRTISO gene was expressed in all tissues tested with the highest expression in maturing fruits. The overexpression of LcCRTISO gene in transgenic tobacco resulted in an increase of total carotenoids in the leaves withβ-carotene and lutein being the predominants. The results obtained here clearly suggested that the LcCRTISO gene was a promising candidate for carotenoid production.

  12. A study of the film formation kinetics on zinc in different acidic corrosion inhibitor solutions by quartz crystal microbalance

    International Nuclear Information System (INIS)

    Chromates conversion coatings provide very effective corrosion protection for many metals. However, the high toxicity of chromate leads to an increasing interest in using non-toxic alternatives such as molybdates, silicates, rare earth metal ions and etc. In this work, quartz crystal microbalance (QCM) was applied as an in-situ technique to follow the film formation process on zinc (plated on gold) in acidic solutions containing an inorganic inhibitor, i.e. potassium chromate, sodium silicate, sodium molybdate or cerium nitrate. Using an equation derived in this work, the interfacial mass change during the film formation process under different conditions was calculated, indicating three different film formation mechanisms. In the presence of K2CrO4 or Na2SiO3, the film growth follows a mix-parabolic law, showing a process controlled by both ion diffusion and surface reaction. The apparent kinetic equations are 0.4t = -17.4 + 20Δm f + (Δm f)2 and 0.1t = 19.0 + 8.4Δm f + 10(Δm f)2 respectively (t and Δm are in seconds and μg/cm2). In solutions containing Na2MoO4, a logarithmic law of Δm f = -24.7 + 6.6 ln t was observed. Changing the inhibitor to Ce(NO3)3, the film growth was found to obey an asymptote law that could be fit into the equation of Δm f = 55.1(1 - exp(-2.6 x 10-3 t))

  13. Individual carotenoid content of SRM 1548 total diet and influence of storage temperature, lyophilization, and irradiation on dietary carotenoids

    International Nuclear Information System (INIS)

    A modified version of the AOAC procedure for the extraction of carotenoids from mixed feeds was coupled with an isocratic reversed-phase liquid chromatography (LC) method to measure individual carotenoids in SRM 1548 total diet and in a high-carotenoid mixed diet (HCMD). The major carotenoids identified in SRM 1548 were lycopene, beta-carotene, lutein, alpha-carotene, and zeaxanthin in descending order of concentration. The concentration of all carotenoids in SRM 1548 decreased as storage temperature increased. Significant differences in carotenoid concentrations occurred between -80 and 4 degrees C storage temperatures. Lyophilization of the HCMD significantly decreased beta-carotene and lycopene concentrations and produced an apparent increase in xanthophyll concentrations. Exposure to gamma-irradiation significantly decreased alpha-carotene and beta-carotene concentrations and led to an apparent increase in P-cryptoxanthin. SRM 1548 was found to be unsuitable for use as a reference material for carotenoid measurements, while HCMD has greater potential as a reference material

  14. Macular carotenoids and age-related maculopathy.

    Science.gov (United States)

    O'Connell, Eamonn; Neelam, Kumari; Nolan, John; Au Eong, Kah-Guan; Beatty, Stephan

    2006-11-01

    Lutein (L) and zeaxanthin (Z) are concentrated at the macula, where they are collectively known as macular pigment (MP), and where they are believed to play a major role in protecting retinal tissues against oxidative stress. Whilst the exact pathogenesis of age-related maculopathy (ARM) remains unknown, the disruption of cellular processes by oxidative stress may play an important role. Manipulation of dietary intake of L and Z has been shown to augment MP, thereby raising hopes that dietary supplementation with these carotenoids might prevent, delay, or modify the course of ARM. This article discusses the scientific rationale supporting the hypothesis that L and Z are protective against ARM, and presents the recent evidence germane to this theory. PMID:17160199

  15. Coke formation during the methanol-to-olefin conversion: in situ microspectroscopy on individual H-ZSM-5 crystals with different Brønsted acidity

    NARCIS (Netherlands)

    Mores, D.; Kornatowski, J.; Olsbye, U.; Weckhuysen, B.M.

    2011-01-01

    Coke formation during the methanol-to-olefin (MTO) conversion has been studied at the single-particle level with in situ UV/Vis and confocal fluorescence microscopy. For this purpose, large H-ZSM-5 crystals differing in their Si/Al molar ratio have been investigated. During MTO, performed at 623 and

  16. Processes of phase formation in CuO-CuBaO2 system and new method of growth of YBa2Cu3Ox single crystals

    International Nuclear Information System (INIS)

    Aimed to design the technology of YBCO superconducting crystal growth the investigations were carried out on phase formation in CuO-CuBaO2 system. A new method of YBa2Cu3Ox single crystal growth was proposed. Crystals were grown from CuyBaOz solution-melt at 900 deg C under oxygen pressure varying of 0.02 to 0.21 atm. for 50-100 h. The use of low pressure allowed one to decrease essentially the temperature of initial treatment that in turn made it possible to reduce the amount of impurities from crucible material. According to technology described superconducting single crystals were obtained as large as 5x5x0.1 mm with transition temperature Ts equal to 93 K

  17. Carotenoids exclusively synthesized in red pepper (capsanthin and capsorubin) protect human dermal fibroblasts against UVB induced DNA damage.

    Science.gov (United States)

    Fernández-García, Elisabet; Carvajal-Lérida, Irene; Pérez-Gálvez, Antonio

    Photoprotection by dietary carotenoids has been linked to their antioxidant properties, in particular quenching of singlet molecular oxygen and scavenging of peroxyl radicals. Here, we compared the DNA-protection and antioxidant effects of selected carotenoids exclusively synthesized in red pepper (capsanthin and capsorubin) to the xanthophyll lutein. Preincubation of human dermal fibroblasts (hdf) with capsanthin and capsorubin significantly counteracted UVB induced cytotoxicity at doses between 0 and 300 mJ cm(-2). Pretreatment of hdf with capsanthin, capsorubin or lutein (1 μM) significantly decreased the formation of DNA strand breaks following irradiation with UVB light. All carotenoids studied decreased caspase-3 cleavage (a marker for UVB-induced apoptosis), however, caspase dependent PARP-1 cleavage was not affected suggesting that the remaining caspase activity is sufficient to promote UVB-induced apoptosis. It is conceivable that carotenoids selectively interfere with cellular responses activated by UVB-mediated damage. Our findings indicate that capsanthin and capsorubin exhibit similar properties to lutein and could be used as a dietary supplement to improve natural photoprotection. PMID:27537377

  18. Introduction of new carotenoids into the bacterial photosynthetic apparatus by combining the carotenoid biosynthetic pathways of Erwinia herbicola and Rhodobacter sphaeroides.

    OpenAIRE

    Hunter, C N; Hundle, B S; Hearst, J E; Lang, H.P.; Gardiner, A.T.; Takaichi, S; Cogdell, R. J.

    1994-01-01

    Carotenoids have two major functions in bacterial photosynthesis, photoprotection and accessory light harvesting. The genes encoding many carotenoid biosynthetic pathways have now been mapped and cloned in several different species, and the availability of cloned genes which encode the biosynthesis of carotenoids not found in the photosynthetic genus Rhodobacter opens up the possibility of introducing a wider range of foreign carotenoids into the bacterial photosynthetic apparatus than would ...

  19. Regulation of orange carotenoid protein activity in cyanobacterial photoprotection

    NARCIS (Netherlands)

    Thurotte, A.; Lopez Igual, R.; Wilson, A.; Comolet, L.; Bourcier de Carbon, C.; Xiao, F.; Kirilovsky, D.

    2015-01-01

    Plants, algae, and cyanobacteria have developed mechanisms to decrease the energy arriving at reaction centers to protect themselves from high irradiance. In cyanobacteria, the photoactive Orange Carotenoid Protein (OCP) and the Fluorescence Recovery Protein are essential elements in this mechanism.

  20. Carotenoids and Their Isomers: Color Pigments in Fruits and Vegetables

    OpenAIRE

    Yueming Jiang; Amin Ismail; Kin-Weng Kong; Hock-Eng Khoo; K. Nagendra Prasad

    2011-01-01

    Fruits and vegetables are colorful pigment-containing food sources. Owing to their nutritional benefits and phytochemicals, they are considered as ‘functional food ingredients’. Carotenoids are some of the most vital colored phytochemicals, occurring as all-trans and cis-isomers, and accounting for the brilliant colors of a variety of fruits and vegetables. Carotenoids extensively studied in this regard include β-carotene, lycopene, lutein and zeaxanthin. Coloration of fruits and vegetables d...

  1. Biochemical Study on the Carotenoids in the Anemonefish, Amphiprion spp.

    OpenAIRE

    Tanaka, Yoshito; Yamamoto, Atsushi; KAMATA, Tadashi; Simpson, Kenneth L.; タナカ, ヨシト; ヤマモト, アツシ; カマタ, タダシ; 田中, 淑人; 山本, 任; 釜田, 忠; シンプソン, ケネス L.

    1992-01-01

    The carotenoid compositions of four species of wild anemonefish, Amphiprion ocellaris, A. biacleatus, A. frenatus and A. clarkii, were analyzed. Alltrans-zeaxanthin was found to be a dominant pigment followed by cis-isomers of zeaxanthin in all four species of anemonefish. Astaxanthin was also isolated as a major carotenoid in these species except A. clarkii, in which no astaxanthin was detected. Astaxanthin, however, was isolated from the eggs of A. clarkii. A feeding experiment was co...

  2. Macular and serum carotenoid concentrations in patients with malabsorption syndromes

    OpenAIRE

    Ward, Matthew S.; Zhao, Da You; Bernstein, Paul S

    2008-01-01

    The carotenoids lutein and zeaxanthin are believed to protect the human macula by absorbing blue light and quenching free radicals. Intestinal malabsorption syndromes such as celiac and Crohn’s disease are known to cause deficiencies of lipid-soluble nutrients. We hypothesized that subjects with nutrient malabsorption syndromes will demonstrate lower carotenoid levels in the macula and blood, and that these lower levels may correlate with early-onset maculopathy. Resonance Raman spectrographi...

  3. Marine Carotenoids against Oxidative Stress: Effects on Human Health

    OpenAIRE

    Maria Alessandra Gammone; Graziano Riccioni; Nicolantonio D'Orazio

    2015-01-01

    Carotenoids are lipid-soluble pigments that are produced in some plants, algae, fungi, and bacterial species, which accounts for their orange and yellow hues. Carotenoids are powerful antioxidants thanks to their ability to quench singlet oxygen, to be oxidized, to be isomerized, and to scavenge free radicals, which plays a crucial role in the etiology of several diseases. Unusual marine environments are associated with a great chemical diversity, resulting in novel bioactive molecules. Thus,...

  4. Changes in the state of carotenoid pigments during greening of etiolated barley seedlings

    International Nuclear Information System (INIS)

    Changes in the metabolism of carotenoid pigments during greening of etiolated barley seedlings have been studied. The experiments were carried out with six-day-old etiolated plants, having a well-developed first leaf, grown on 1/2 Knop nutrient solution. The plants were illuminated with light, 10 000 lux intensity. Samples for analysis were taken at nil, 2, 4, 6, 8 and 12 hours. The extraction of the pigments was effected with the aid of the fractionation method according to Chernomorski and Sapozhnikov. The specific radioactivity of the individual carotenoid pigments was measured. To this end the plants were placed on a solution of sodium acetate (14C) for 18 hours before illumination. The radiochemical purification of the pigments was carried out on an aluminium oxide column, after their chromatographic separation on paper. The results obtained from the experiments show that the illumination of the plants leads to a 2.4-fold increase in the total amount of carotenoids. The amount of the carotene increases approximately about 8 times over a 24-hour period and that of the xanthophylles - almost two times. A rhythm is observed in the formation of lutein and violaxanthin, which is discussed in connection with the participation of these pigments in the formation and the activity of the photosynthetic apparatus. The data on the changes in the state of the individual pigments indicate differences in accordance with their nature. The distinct manifestation of the heterogeneity of the carotene is observed in the case where the photosynthesis apparatus is fully formed. Obviously, the manifestation of the heterogeneity of that pigment is related to the formation of chloroplast and changes in the environment. Data on changes in the specific radioactivity of the easily-extractable fractions of the lutein and the violaxanthin show that the newly-synthesized molecules are more easily extractable. (author)

  5. Carotenoids are essential for the assembly of cyanobacterial photosynthetic complexes.

    Science.gov (United States)

    Tóth, Tünde N; Chukhutsina, Volha; Domonkos, Ildikó; Knoppová, Jana; Komenda, Josef; Kis, Mihály; Lénárt, Zsófia; Garab, Győző; Kovács, László; Gombos, Zoltán; van Amerongen, Herbert

    2015-10-01

    In photosynthetic organisms, carotenoids (carotenes and xanthophylls) are important for light harvesting, photoprotection and structural stability of a variety of pigment-protein complexes. Here, we investigated the consequences of altered carotenoid composition for the functional organization of photosynthetic complexes in wild-type and various mutant strains of the cyanobacterium Synechocystis sp. PCC 6803. Although it is generally accepted that xanthophylls do not play a role in cyanobacterial photosynthesis in low-light conditions, we have found that the absence of xanthophylls leads to reduced oligomerization of photosystems I and II. This is remarkable because these complexes do not bind xanthophylls. Oligomerization is even more disturbed in crtH mutant cells, which show limited carotenoid synthesis; in these cells also the phycobilisomes are distorted despite the fact that these extramembranous light-harvesting complexes do not contain carotenoids. The number of phycocyanin rods connected to the phycobilisome core is strongly reduced leading to high amounts of unattached phycocyanin units. In the absence of carotenoids the overall organization of the thylakoid membranes is disturbed: Photosystem II is not formed, photosystem I hardly oligomerizes and the assembly of phycobilisomes remains incomplete. These data underline the importance of carotenoids in the structural and functional organization of the cyanobacterial photosynthetic machinery. PMID:26045333

  6. Seeking carotenoid pigments in amber-preserved fossil feathers

    Science.gov (United States)

    Thomas, Daniel B.; Nascimbene, Paul C.; Dove, Carla J.; Grimaldi, David A.; James, Helen F.

    2014-06-01

    Plumage colours bestowed by carotenoid pigments can be important for visual communication and likely have a long evolutionary history within Aves. Discovering plumage carotenoids in fossil feathers could provide insight into the ecology of ancient birds and non-avian dinosaurs. With reference to a modern feather, we sought chemical evidence of carotenoids in six feathers preserved in amber (Miocene to mid-Cretaceous) and in a feather preserved as a compression fossil (Eocene). Evidence of melanin pigmentation and microstructure preservation was evaluated with scanning electron and light microscopies. We observed fine microstructural details including evidence for melanin pigmentation in the amber and compression fossils, but Raman spectral bands did not confirm the presence of carotenoids in them. Carotenoids may have been originally absent from these feathers or the pigments may have degraded during burial; the preservation of microstructure may suggest the former. Significantly, we show that carotenoid plumage pigments can be detected without sample destruction through an amber matrix using confocal Raman spectroscopy.

  7. Spectroscopic properties of the carotenoid 3´-hydroxyechinenone in the orange carotenoid protein from the cyanobacterium Arthrospira maxima

    Czech Academy of Sciences Publication Activity Database

    Polívka, Tomáš; Kerfeld, C.A.; Pascher, T.; Sundström, V.

    2007-01-01

    Roč. 44, č. 10 (2007), s. 3994-4003. ISSN 0006-2960 Institutional research plan: CEZ:AV0Z50510513 Keywords : carotenoids * Spectroscopic properties Subject RIV: CE - Biochemistry Impact factor: 3.368, year: 2007

  8. Study of major aromatic compounds in port wines from carotenoid degradation

    OpenAIRE

    Ferreira, Antonio César Silva; Monteiro, Judith; Oliveira, Carla; de Pinho, Paula Guedes

    2008-01-01

    The carotenoids degradation and the formation of volatiles were examined by simulating Port wine aging. A two year old red Port wine was saturated with oxygen, supplemented with lutein and b-carotene and kept at 60ºC during 87 h. A similar study was performed in a model wine solution. Results showed that the percentage decrease in lutein levels was, respectively, 79% and 95%, in the wine model solution and in the Port wine, and 55% and 10% for b-carotene, indicating that lutein was more sensi...

  9. Misorientation effect of grain boundary on the formation of discontinuous precipitation in second and third generation single crystal superalloys

    Directory of Open Access Journals (Sweden)

    Yu Zhengrong

    2014-01-01

    Full Text Available [001] tilt artificial grain boundaries of Ni-based single crystal superalloys CMSX-4 and DD10 have been prepared by self-diffusion bonding. The microstructural stability of 0 ∼ 30∘ artificial grain boundaries have been investigated after heat treatment at 1100 ∘C for 0 ∼ 300 h. TCP phases and cellular colony developed on boundaries are related to misorientation angle of the bonded boundaries of DD10 and DD10 alloys as well as the bonded boundaries of CMSX-4 and DD10 alloys. The heterogeneous nucleation of TCP phase, enveloped by γ′ film, occurred along 15∘ and 20∘ boundaries. Discontinuous Precipitation (DP reaction occurred along high misorientation angle (20∘∼ 30∘ boundaries. However, no TCP phase formation existed along grain boundaries with different misorientation angles in CMSX-4/CMSX-4 bonded alloys as well as for a 0∘ boundary in DD10/DD10 and CMSX-4/DD10 bonded alloys. The current study clearly suggests that grain boundary precipitation and its morphology were influenced by the misorientation angle of grain boundary and the content of refractory elements in alloy.

  10. Formation and stability of Fe-rich precipitates in dilute Zr(Fe) single-crystal alloys

    International Nuclear Information System (INIS)

    The formation and stability of Fe-rich precipitates in two α-Zr(Fe) single-crystal alloys with nominal compositions (I, 50 ppma Fe, and II, 650 ppma Fe) have been investigated (the maximum solid solubility of Fe in α-Zr is 180 ppma - 800 C). Optical microscopy, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) have been used to examine the characteristics of Fe-rich precipitates. SEM and TEM micrographs show that in as-grown alloy II, Zr2Fe precipitates are located at 'stringers'. Precipitates were not observed in as-grown alloy I. During annealing, below the solvus, Fe diffuses to the surfaces to form Zr3Fe precipitates in both alloys. The precipitates on the surfaces of alloy I tend to be star-like (0001) or pyramidal (1010), and their distribution is heterogeneous. Dissolution of Zr3Fe surface precipitates of alloy I (annealing above the solvus) leaves precipitate-like features on the surfaces. Zr2Fe precipitates in as-grown alloy II can be dissolved only by β-phase annealing. (Author) 8 figs., 18 refs

  11. Relative crystal stability of AlxFeNiCrCo high entropy alloys from XRD analysis and formation energy calculation

    International Nuclear Information System (INIS)

    Electronic structure of AlxFeNiCrCo (x ≤ 3) high-entropy alloys (HEAs) was calculated using the Korringa–Kohn–Rostoker method combined with the coherent potential approximation (KKR-CPA). Total energy minimization was performed for bcc and fcc structures in each alloy composition. The phase stability was investigated from the total energy analysis, which finally allowed to determine the bcc–fcc phase transition for aluminium concentration close to 13 at%. It inspired us to synthesize AlxFeNiCrCo (0 ≤ x ≤ 1.5) using two procedures based on arc melting and sintering to allow for observation of entropy effect on phase formation. The XRD measurements evidently proved an occurence of fcc or bcc structure and their coexistence, depending on Al concentration and temperature. This finding remains in good agreement with theoretical results from free energy analysis, when accounting for KKR-CPA total energy as well as entropy terms. Furthermore, the structure preference, from fcc to bcc HEAs, with increasing Al content was discussed in view of total and atomic-dependent density of states computed in non-magnetic and paramagnetic-like states. - Highlights: • Crystal stability and electronic properties of high entropy alloys from KKR-CPA. • Influence of configuration entropy on phase preference (or coexistence). • Effect of configuration entropy on phase stability: arc melting viz. sintering. • Ab initio calculations (accounting for disorder) of phase preference in HEA

  12. Spatially selective Er/Yb-doped CaF2 crystal formation by CO2 laser exposure

    International Nuclear Information System (INIS)

    Highlights: • Oxyfluoride glass–ceramics containing CaF2 nanocrystals doped with Er3+ and Yb3+ ions were formed on the glass surface by CO2 laser and a heat gun exposure. • Most of Er and Yb ions were distributed inside CaF2 nanocrystals and fluorine loss was observed in the EDS element maps. • IR-to-VIS upconversion emission efficiency of laser annealed glass ceramics was much increased and compared with that of the furnace-annealed glass ceramics. • Distributed volume of the glass ceramics were estimated by a confocal fluorescence microscope imaging. - Abstract: We report the glass–ceramic precipitation on the oxyfluoride glass surface by spatially selective annealing with a CO2 laser and a heat gun exposure. X-ray diffraction analysis showed the formation of major CaF2 and miner Ca2SiO4 nanoparticles. We observed ∼100 nm nanoparticle aggregation by tunneling electron microscopy and element distribution in glass and crystal phases. Spatial distribution of glass ceramics near the glass surface was probed by confocal fluorescence microscope by using much enhanced emission from the Er ions in the laser-treated area. Strong emissions at 365 nm excitation and visible up-conversion emissions at 980 nm excitation also indicated well incorporation of Er and Yb ions into a crystalline environment

  13. Diversity, physiology, and evolution of avian plumage carotenoids and the role of carotenoid-protein interactions in plumage color appearance.

    Science.gov (United States)

    LaFountain, Amy M; Prum, Richard O; Frank, Harry A

    2015-04-15

    The diversity of vibrant plumage colors in birds has evolved as a direct result of social and environmental pressures. To fully understand these underlying pressures it is necessary to elucidate the mechanisms for the creation of novel plumage colors which include the metabolic transformations of dietary carotenoids and spectral tuning of the molecules within the feather protein environment. Recent advances in this field have greatly expanded the number and breadth of avian species for which plumage pigmentation has been characterized, making it possible to reconstruct the phylogenetic history of carotenoid usage in plumage. Resonance Raman and classical Raman spectroscopic techniques have been employed with great effect in the study of carotenoids in situ. The application of these methods have two benefits: to identify carotenoids in feathers that are unavailable for destructive sampling; and to study the spectral tuning resulting from the interaction between the carotenoids and the proteins to which they are bound. This review presents a summary of recent advances in the understanding of the molecular factors controlling the coloration of avian carotenoid plumage obtained through the application of both bioanalytical and spectroscopic methodologies. PMID:25637658

  14. Validation model for Raman based skin carotenoid detection.

    Science.gov (United States)

    Ermakov, Igor V; Gellermann, Werner

    2010-12-01

    Raman spectroscopy holds promise as a rapid objective non-invasive optical method for the detection of carotenoid compounds in human tissue in vivo. Carotenoids are of interest due to their functions as antioxidants and/or optical absorbers of phototoxic light at deep blue and near UV wavelengths. In the macular region of the human retina, carotenoids may prevent or delay the onset of age-related tissue degeneration. In human skin, they may help prevent premature skin aging, and are possibly involved in the prevention of certain skin cancers. Furthermore, since carotenoids exist in high concentrations in a wide variety of fruits and vegetables, and are routinely taken up by the human body through the diet, skin carotenoid levels may serve as an objective biomarker for fruit and vegetable intake. Before the Raman method can be accepted as a widespread optical alternative for carotenoid measurements, direct validation studies are needed to compare it with the gold standard of high performance liquid chromatography. This is because the tissue Raman response is in general accompanied by a host of other optical processes which have to be taken into account. In skin, the most prominent is strongly diffusive, non-Raman scattering, leading to relatively shallow light penetration of the blue/green excitation light required for resonant Raman detection of carotenoids. Also, sizable light attenuation exists due to the combined absorption from collagen, porphyrin, hemoglobin, and melanin chromophores, and additional fluorescence is generated by collagen and porphyrins. In this study, we investigate for the first time the direct correlation of in vivo skin tissue carotenoid Raman measurements with subsequent chromatography derived carotenoid concentrations. As tissue site we use heel skin, in which the stratum corneum layer thickness exceeds the light penetration depth, which is free of optically confounding chromophores, which can be easily optically accessed for in vivo RRS

  15. Carotenoids: Actual knowledge on food sources, intakes, stability and bioavailability and their protective role in humans

    DEFF Research Database (Denmark)

    Maiani, Giuseppe; Castón, María Jesús Periago; Catasta, Giovina;

    2009-01-01

    Carotenoids are one of the major food micronutrients in human diets and the overall objective of this review is to re-examine the role of carotenoids in human nutrition. We have emphasized the attention on the following carotenoids present in food and human tissues: -carotene, -cryptoxanthin......, -carotene, lycopene, lutein and zeaxanthin; we have reported the major food sources and dietary intake of these compounds. We have tried to summarize positive and negative effects of food processing, storage, cooking on carotenoid content and carotenoid bioavailability. In particular, we have evidenced...... the possibility to improve carotenoids bioavailability in accordance with changes and variations of technology procedures....

  16. Transformation reactions and recycling of carotenoids and chlorins in the Peru upwelling region (15°S, 75°W)

    Science.gov (United States)

    Repeta, Daniel J.; Gagosian, Robert B.

    1984-06-01

    Total chlorins and carotenoids were measured in suspended paniculate matter, sediment trap, and zooplankton fecal pellet samples collected in the Peru upwelling region. Individual carotenoids were analyzed by high pressure liquid chromatography and mass spectrometry. Fucoxanthin, diadinoxanthin, diatoxanthin, carotene, and peridinin constitute > 95% of the total carotenoid pigments in suspended paniculate matter samples. However, sediment trap and zooplankton fecal pellet samples contained significant amounts of the carotenoid transformation products fucoxanthinol, fucoxanthin 5'-dehydrate, fucoxanthinol 5'-dehydrate, peridininol and peridininol 5'-dehydrate. These samples were further characterized by high values of the ratio fucoxanthinol/total fucopigments ( f/F t) and low values of the ratio total carotenoids /total chlorins. Three reactions are proposed to account for the formation of observed products: heterotrophic ester hydrolysis, chemically mediated epoxide rearrangement, and microbially mediated dehydration. The distribution of specific transformation products within the samples suggests that heterotrophic ester hydrolysis is a general transformation pathway operative in the water column on a wide suite of organic esters. Epoxide rearrangement and dehydration appear to occur over a longer time scale and are more typical of sedimentary environments.

  17. Inactivation of normal and mutant Neurospora crassa conidia by visible light and near-UV: role of 1O2, carotenoid composition and sensitizer location

    International Nuclear Information System (INIS)

    Inactivation of Neurospora crassa conidia from wild-type and mutant strains by visible and near-ultraviolet light was investigated in the presence and absence of photosensitizing dyes. Inactivation by near-UV was virtually unchanged by the presence of deuterium oxide or azide suggesting that, contrary to the situation with visible light and photosensitizing dyes, 1O2 is not involved in any substantial way in the formation of lethal lesions. Carotenoid deficient strains were similar to wild-type strains in sensitivity to near-UV inactivation which is consistent with 1O2 not being involved. Photodynamic inactivation of conidia by visible light occurred in the presence of methylene blue (MB), toluidine blue O (TB), or acridine orange (AO). Carotenoid deficient strains were more sensitive to such inactivation only when MB and TB were used. This suggests that MB and TB mediated damage involves the cell membrane where carotenoids are available for quenching, whereas AO mediated damage occurs in the nucleus sequestered from the protective influence of carotenoids. A newly isolated, lemon-yellow mutant exhibited sensitivities to photodynamic inactivation similar to other pure-white mutants. The sensitivity of this pigmented mutant is apparently related to insufficient unsaturation of the two coloured carotenoids produced by the mutant. (author)

  18. Inactivation of normal and mutant Neurospora crassa conidia by visible light and near-UV: role of /sup 1/O/sub 2/, carotenoid composition and sensitizer location

    Energy Technology Data Exchange (ETDEWEB)

    Thomas, S.A.; Sargent, M.L.; Tuveson, R.W. (Illinois Univ., Urbana (USA))

    1981-03-01

    Inactivation of Neurospora crassa conidia from wild-type and mutant strains by visible and near-ultraviolet light was investigated in the presence and absence of photosensitizing dyes. Inactivation by near-UV was virtually unchanged by the presence of deuterium oxide or azide suggesting that, contrary to the situation with visible light and photosensitizing dyes, /sup 1/O/sub 2/ is not involved in any substantial way in the formation of lethal lesions. Carotenoid deficient strains were similar to wild-type strains in sensitivity to near-UV inactivation which is consistent with /sup 1/O/sub 2/ not being involved. Photodynamic inactivation of conidia by visible light occurred in the presence of methylene blue (MB), toluidine blue O (TB), or acridine orange (AO). Carotenoid deficient strains were more sensitive to such inactivation only when MB and TB were used. This suggests that MB and TB mediated damage involves the cell membrane where carotenoids are available for quenching, whereas AO mediated damage occurs in the nucleus sequestered from the protective influence of carotenoids. A newly isolated, lemon-yellow mutant exhibited sensitivities to photodynamic inactivation similar to other pure-white mutants. The sensitivity of this pigmented mutant is apparently related to insufficient unsaturation of the two coloured carotenoids produced by the mutant.

  19. Improving carotenoid extraction from tomato waste by pulsed electric fields.

    Directory of Open Access Journals (Sweden)

    JavierRaso

    2014-08-01

    Full Text Available In this investigation, the influence of the application of Pulsed Electric Fields (PEF of different intensities (3-7 kV/cm and 0-300 μs on the carotenoid extraction from tomato peel and pulp in a mixture of hexane:acetone:ethanol was studied with the aim of increasing extraction yield or reducing the percentage of the less green solvents in the extraction medium. According to the cellular disintegration index, the optimum treatment time for the permeabilization of tomato peel and pulp at different electric field strengths was 90 µs. The PEF permeabilization of tomato pulp did not significantly increase the carotenoid extraction. However, a PEF-treatment at 5 kV/cm improved the carotenoid extraction from tomato peel by 39 % as compared with the control in a mixture of hexane:ethanol:acetone (50:25:25. Further increments of electric field from 5 to 7 kV/cm did not increase significantly the extraction of carotenoids. . The presence of acetone in the solvent mixture did not positively affect the carotenoid extraction when the tomato peels were PEF-treated. Response surface methodology was used to determine the potential of PEF for reducing the percentage of hexane in a hexane:ethanol mixture. The application of a PEF-treatment allowed reducing the hexane percentage from 45 to 30 % without affecting the carotenoid extraction yield. The antioxidant capacity of the extracts obtained from tomato peel was correlated with the carotenoid concentration and it was not affected by the PEF-treatment.

  20. Recent patents on the extraction of carotenoids.

    Science.gov (United States)

    Riggi, Ezio

    2010-01-01

    This article reviews the patents that have been presented during the last decade related to the extraction of carotenoids from various forms of organic matter (fruit, vegetables, animals), with an emphasis on the methods and mechanisms exploited by these technologies, and on technical solutions for the practical problems related to these technologies. I present and classify 29 methods related to the extraction processes (physical, mechanical, chemical, and enzymatic). The large number of processes for extraction by means of supercritical fluids and the growing number of large-scale industrial plants suggest a positive trend towards using this technique that is currently slowed by its cost. This trend should be reinforced by growing restrictions imposed on the use of most organic solvents for extraction of food products and by increasingly strict waste management regulations that are indirectly promoting the use of extraction processes that leave the residual (post-extraction) matrix substantially free from solvents and compounds that must subsequently be removed or treated. None of the reviewed approaches is the best answer for every extractable compound and source, so each should be considered as one of several alternatives, including the use of a combination of extraction approaches. PMID:20653552

  1. About the mechanism for paramagnetic centers formation under the radiolysis of RbNO3 and CsNO3 crystals

    Science.gov (United States)

    Anan'ev, V.; Pak, V.

    2014-05-01

    The accumulation of paramagnetic centers - NO2rad and Orad - in RbNO3 and CsNO3 crystals under γ-irradiation at 310 K and their thermal stability has been studied. The values of the initial radiation chemical yield of NO2rad were calculated to be ∼2.5 × 10-2 (100 eV)-1 in both nitrates. These values for Orad - are equal to 0.05 and 0.38 (100 eV)-1 for RbNO3 and CsNO3, respectively. The heating of irradiated crystals results in the decay of NO2rad and Orad - centers with simultaneously appearance of the ozonide ion. The mechanism for paramagnetic centers formation under γ-irradiation of RbNO3 and CsNO3 crystals has been discussed.

  2. About the mechanism for paramagnetic centers formation under the radiolysis of RbNO3 and CsNO3 crystals

    International Nuclear Information System (INIS)

    The accumulation of paramagnetic centers – NO2· and O·− in RbNO3 and CsNO3 crystals under γ-irradiation at 310 K and their thermal stability has been studied. The values of the initial radiation chemical yield of NO2· were calculated to be ∼2.5 × 10−2 (100 eV)−1 in both nitrates. These values for O·− are equal to 0.05 and 0.38 (100 eV)−1 for RbNO3 and CsNO3, respectively. The heating of irradiated crystals results in the decay of NO2· and O·− centers with simultaneously appearance of the ozonide ion. The mechanism for paramagnetic centers formation under γ-irradiation of RbNO3 and CsNO3 crystals has been discussed

  3. Formation of ZrO2 cubic phase microcrystals during crystallization of amorphous films deposited by laser ablation of Zr in an oxygen atmosphere

    Science.gov (United States)

    Bagmut, A. G.; Bagmut, I. A.; Reznik, N. A.

    2016-06-01

    The structure and phase transformations during annealing of zirconium dioxide films grown by pulsed laser sputtering of a Zr target in an oxygen atmosphere have been studied by transmission electron microscopy and electron diffraction methods. The conditions of the formation of both amorphous and cubic ZrO2 phases have been determined. The electron beam impact on the amorphous film in vacuum is accompanied by the formation of zirconium dioxide microcrystals with fcc lattice. The average grain size in the crystallized film is ˜0.5 μm. The phase transformation is accompanied by film material densification. The relative change in the density during ZrO2 crystallization is 10.27 ± 2.14%.

  4. Effects of micro electric current load during cooling of plant tissues on intracellular ice crystal formation behavior and pH.

    Science.gov (United States)

    Ninagawa, Takako; Kawamura, Yukio; Konishi, Tadashi; Narumi, Akira

    2016-08-01

    Cryopreservation techniques are expected to evolve further to preserve biomaterials and foods in a fresh state for extended periods of time. Long-term cryopreservation of living materials such as food and biological tissue is generally achieved by freezing; thus, intracellular freezing occurs. Intracellular freezing injures the cells and leads to cell death. Therefore, a dream cryopreservation technique would preserve the living materials without internal ice crystal formation at a temperature low enough to prevent bacterial activity. This study was performed to investigate the effect of micro electrical current loading during cooling as a new cryopreservation technique. The behavior of intracellular ice crystal formation in plant tissues with or without an electric current load was evaluated using the degree of supercooling, degree of cell deformation, and grain size and growing rate of intracellular ice crystal. Moreover, the transition of intracellular pH during plant tissue cooling with or without electric current loading was also examined using the fluorescence intensity ratio to comprehend cell activity at lower temperatures. The results indicated that micro electric current load did not only decrease the degree of cell deformation and grain size of intracellular ice crystal but also reduced the decline in intracellular pH due to temperature lowering, compared with tissues subjected to the same cooling rate without an electric current load. Thus, the effect of electric current load on cryopreservation and the potential of a new cryopreservation technique using electric current load were discussed based on these results. PMID:27343137

  5. Ozone-Induced Responses in Croton floribundus Spreng. (Euphorbiaceae): Metabolic Cross-Talk between Volatile Organic Compounds and Calcium Oxalate Crystal Formation

    OpenAIRE

    Poliana Cardoso-Gustavson; Vanessa Palermo Bolsoni; Debora Pinheiro de Oliveira; Maria Tereza Gromboni Guaratini; Marcos Pereira Marinho Aidar; Mauro Alexandre Marabesi; Edenise Segala Alves; Silvia Ribeiro de Souza

    2014-01-01

    Here, we proposed that volatile organic compounds (VOC), specifically methyl salicylate (MeSA), mediate the formation of calcium oxalate crystals (COC) in the defence against ozone (O3) oxidative damage. We performed experiments using Croton floribundus, a pioneer tree species that is tolerant to O3 and widely distributed in the Brazilian forest. This species constitutively produces COC. We exposed plants to a controlled fumigation experiment and assessed biochemical, physiological, and morph...

  6. The formation of carbonic and silicon dioxide structured films through the decomposition of molecules on the surface of ionic crystals under the action of IR femtosecond laser radiation

    Science.gov (United States)

    Kompanets, V. O.; Laptev, V. B.; Pigul’skii, S. V.; Ryabov, E. A.; Chekalin, S. V.; Blank, V. D.; Denisov, V. N.; Kravchuk, K. S.; Kulnitskiy, B. A.; Perezhogin, I. A.

    2016-06-01

    This study relates to the formation of carbon and silicon dioxide films that occurs as a result of the decomposition of organic and silicon-containing molecules on the surface of ionic crystals under IR femtosecond laser radiation of moderate intensity (~1011 W cm‑2) without molecular decomposition in the gas phase. We found that transparent graphite oxide films formed in the case of CO2 molecule decomposition.

  7. Marine Carotenoids against Oxidative Stress: Effects on Human Health.

    Science.gov (United States)

    Gammone, Maria Alessandra; Riccioni, Graziano; D'Orazio, Nicolantonio

    2015-10-01

    Carotenoids are lipid-soluble pigments that are produced in some plants, algae, fungi, and bacterial species, which accounts for their orange and yellow hues. Carotenoids are powerful antioxidants thanks to their ability to quench singlet oxygen, to be oxidized, to be isomerized, and to scavenge free radicals, which plays a crucial role in the etiology of several diseases. Unusual marine environments are associated with a great chemical diversity, resulting in novel bioactive molecules. Thus, marine organisms may represent an important source of novel biologically active substances for the development of therapeutics. In this respect, various novel marine carotenoids have recently been isolated from marine organisms and displayed several utilizations as nutraceuticals and pharmaceuticals. Marine carotenoids (astaxanthin, fucoxanthin, β-carotene, lutein but also the rare siphonaxanthin, sioxanthin, and myxol) have recently shown antioxidant properties in reducing oxidative stress markers. This review aims to describe the role of marine carotenoids against oxidative stress and their potential applications in preventing and treating inflammatory diseases. PMID:26437420

  8. Carotenoid composition of strawberry tree (Arbutus unedo L.) fruits.

    Science.gov (United States)

    Delgado-Pelayo, Raúl; Gallardo-Guerrero, Lourdes; Hornero-Méndez, Dámaso

    2016-05-15

    The carotenoid composition of strawberry tree (Arbutus unedo) fruits has been characterised in detail and quantified for the first time. According to the total carotenoid content (over 340 μg/g dw), mature strawberry tree berries can be classified as fruits with very high carotenoid content (>20 μg/g dw). (all-E)-Violaxanthin and 9Z-violaxanthin were found to be the major carotenoid pigments, accounting for more than 60%, responsible for the bright colour of the flesh of ripe fruits. In addition other 5,6-epoxide carotenoids, such as (all-E)-neoxanthin, (9'Z)-neoxanthin (all-E)-antheraxanthin and lutein 5,6-epoxide, together with (all-E)-lutein, (all-E)-zeaxanthin and (all-E)-β-carotene were found at high levels (>5-20 μg/g dw). The LC-MS (APCI+) analysis of the xanthophyll fraction in their native state (direct extract) revealed that most of them (>90%) were totally esterified with saturated fatty acids (capric, lauric, myristic, palmitic and stearic). Monoesters, homodiesters and heterodiesters of (all-E)-violaxanthin and 9Z-violaxanthin were the major pigments. PMID:26775958

  9. Marine Carotenoids against Oxidative Stress: Effects on Human Health

    Directory of Open Access Journals (Sweden)

    Maria Alessandra Gammone

    2015-09-01

    Full Text Available Carotenoids are lipid-soluble pigments that are produced in some plants, algae, fungi, and bacterial species, which accounts for their orange and yellow hues. Carotenoids are powerful antioxidants thanks to their ability to quench singlet oxygen, to be oxidized, to be isomerized, and to scavenge free radicals, which plays a crucial role in the etiology of several diseases. Unusual marine environments are associated with a great chemical diversity, resulting in novel bioactive molecules. Thus, marine organisms may represent an important source of novel biologically active substances for the development of therapeutics. In this respect, various novel marine carotenoids have recently been isolated from marine organisms and displayed several utilizations as nutraceuticals and pharmaceuticals. Marine carotenoids (astaxanthin, fucoxanthin, β-carotene, lutein but also the rare siphonaxanthin, sioxanthin, and myxol have recently shown antioxidant properties in reducing oxidative stress markers. This review aims to describe the role of marine carotenoids against oxidative stress and their potential applications in preventing and treating inflammatory diseases.

  10. Carotenoids as a Source of Antioxidants in the Diet.

    Science.gov (United States)

    Xavier, Ana Augusta Odorissi; Pérez-Gálvez, Antonio

    2016-01-01

    Carotenoids, widely distributed fat-soluble pigments, are responsible for the attractive colorations of several fruits and vegetables commonly present in our daily diet. They are particularly abundant in yellow-orange fruits (carrots, tomatoes, pumpkins, peppers, among others) and, although masked by chlorophylls, in dark green leafy vegetables. Several health benefits have been attributed to carotenoids or to foods rich in these pigments, by means of different mechanisms-of-action, including the role as provitamin A of almost 50 different carotenoids and the antioxidant activity that protects cells and tissues from damage of free radicals and singlet oxygen, providing enhancement of the immune function, protection from sunburn reactions and delaying the onset of certain types of cancer. Common food sources and the efficiency of the absorption of carotenoids, analytical approaches used for measurement of their antioxidant effect and an overview of some epidemiological studies that have been performed to assess the beneficial impact of carotenoids in human health are outlined in this chapter. PMID:27485230

  11. Vibronic coupling in the excited-states of carotenoids.

    Science.gov (United States)

    Miki, Takeshi; Buckup, Tiago; Krause, Marie S; Southall, June; Cogdell, Richard J; Motzkus, Marcus

    2016-04-20

    The ultrafast femtochemistry of carotenoids is governed by the interaction between electronic excited states, which has been explained by the relaxation dynamics within a few hundred femtoseconds from the lowest optically allowed excited state S2 to the optically dark state S1. Extending this picture, some additional dark states (3A and 1B) and their interaction with the S2 state have also been suggested to play a major role in the ultrafast deactivation of carotenoids and their properties. Here, we investigate the interaction between such dark and bright electronic excited states of open chain carotenoids, particularly its dependence on the number of conjugated double bonds (N). We focus on the ultrafast wave packet motion on the excited potential surface, which is modified by the interaction between bright and dark electronic states. Such a coupling between electronic states leads to a shift of the vibrational frequency during the excited-state evolution. In this regard, pump-degenerate four-wave mixing (pump-DFWM) is applied to a series of carotenoids with different numbers of conjugated double bonds N = 9, 10, 11 and 13 (neurosporene, spheroidene, lycopene and spirilloxanthin, respectively). Moreover, we demonstrate in a closed-chain carotenoid (lutein) that the coupling strength and therefore the vibrational shift can be tailored by changing the energy degeneracy between the 1B and 1B states via solvent interaction. PMID:27055720

  12. An update on microbial carotenoid production: application of recent metabolic engineering tools.

    Science.gov (United States)

    Das, Amitabha; Yoon, Sang-Hwal; Lee, Sook-Hee; Kim, Jae-Yean; Oh, Deok-Kun; Kim, Seon-Won

    2007-12-01

    Carotenoids are ubiquitous pigments synthesized by plants, fungi, algae, and bacteria. Industrially, carotenoids are used in pharmaceuticals, neutraceuticals, and animal feed additives, as well as colorants in cosmetics and foods. Scientific interest in dietary carotenoids has increased in recent years because of their beneficial effects on human health, such as lowering the risk of cancer and enhancement of immune system function, which are attributed to their antioxidant potential. The availability of carotenoid genes from carotenogenic microbes has made possible the synthesis of carotenoids in non-carotenogenic microbes. The increasing interest in microbial sources of carotenoid is related to consumer preferences for natural additives and the potential cost effectiveness of creating carotenoids via microbial biotechnology. In this review, we will describe the recent progress made in metabolic engineering of non-carotenogenic microorganisms with particular focus on the potential of Escherichia coli for improved carotenoid productivity. PMID:17912511

  13. Generation of structurally novel short carotenoids and study of their biological activity

    DEFF Research Database (Denmark)

    Kim, Se Hyeuk; Kim, Moon S.; Lee, Bun Y.;

    2016-01-01

    Recent research interest in phytochemicals has consistently driven the efforts in the metabolic engineering field toward microbial production of various carotenoids. In spite of systematic studies, the possibility of using C30 carotenoids as biologically functional compounds has not been explored...... thus far. Here, we generated 13 novel structures of C30 carotenoids and one C35 carotenoid, including acyclic, monocyclic, and bicyclic structures, through directed evolution and combinatorial biosynthesis, in Escherichia coli. Measurement of radical scavenging activity of various C30 carotenoid...... structures revealed that acyclic C30 carotenoids showed higher radical scavenging activity than did DL-atocopherol. We could assume high potential biological activity of the novel structures of C30 carotenoids as well, based on the neuronal differentiation activity observed for the monocyclic C30 carotenoid...

  14. Near-infrared transient absorption study of the orange carotenoid protein

    Czech Academy of Sciences Publication Activity Database

    Polívka, Tomáš; Chábera, P.; Sundström, V.; Kerfeld, C.A.

    Nové Hrady : Academic and University Center, 2008. s. 34. [ESF Workshop on Novel Methods in Exploring Carotenoid Excited State Dynamics. 21.09.2008-25.09.2008, Nové Hrady] Keywords : carotenoids Subject RIV: BO - Biophysics

  15. Direct quantification of carotenoids in low fat babyfoods via laser photoacoustics and colorimetric index a

    NARCIS (Netherlands)

    Doka, O.; Ajtony, Z.; Bicanic, D.D.; Valinger, D.; Vegvari, G.

    2014-01-01

    Carotenoids are important antioxidants found in various foods including those for nutrition of infants. In this investigation, the total carotenoid content (TCC) of nine different commercially available baby foods was quantified using colorimetric index a * obtained via reflectance colorimetry (RC)

  16. Development of carotenoid-enriched vegetables with increased nutritional quality and visual appearance

    Science.gov (United States)

    Carotenoids are a class of red, orange and yellow pigments widely distributed in nature. Biotech approach has been proved to be effective in successfully engineering of carotenoid content in food crops with better health and visual appearance....

  17. The Or gene enhances carotenoid accumulation and stability during post-harvest storage of potato tubers

    Science.gov (United States)

    Provitamin A carotenoids in staple crops are not very stable during storage and their loss compromises nutritional quality. To elucidate the fundamental mechanisms underlying carotenoid accumulation and stability, we investigated transgenic potato tubers that express the cauliflower Orange (Or) gene...

  18. Formation of color centers optical waveguide in LN crystal by implanting it with 3 MeV oxygen ions

    International Nuclear Information System (INIS)

    Optical waveguide was fabricated by implanting 3 MeV oxygen ions of 5×1014 and 1.5×1015 ions/cm2 into congruent lithium niobate (LN) crystals and annealing them at 200℃-500℃. Optical spectrum was used to investigation defects in the optical waveguide. The results revealed the reduction of Li ions in the implanted LN crystals. The absorption of LN crystal increased with the dose of oxygen ion. This showed that the color centers were formed increasingly with the oxygen ion dose. The color centers and defects affecting the optical absorption include oxygen vacancy, exciton, interstitial atoms and electrons captured by Nb ions occupying the Li ion site. The color centers and defects caused increase of the absorption in the implanted the LN crystals. The annealing temperature seemed to have little effect on reduction of color centers. The optical waveguide of the implanted LN crystal exhibits high temperature stability. (authors)

  19. Disruption of a CAROTENOID CLEAVAGE DIOXYGENASE 4 gene converts flower colour from white to yellow in Brassica species.

    Science.gov (United States)

    Zhang, Bao; Liu, Chao; Wang, Yaqin; Yao, Xuan; Wang, Fang; Wu, Jiangsheng; King, Graham J; Liu, Kede

    2015-06-01

    In Brassica napus, yellow petals had a much higher content of carotenoids than white petals present in a small number of lines, with violaxanthin identified as the major carotenoid compound in yellow petals of rapeseed lines. Using positional cloning we identified a carotenoid cleavage dioxygenase 4 gene, BnaC3.CCD4, responsible for the formation of flower colour, with preferential expression in petals of white-flowered B. napus lines. Insertion of a CACTA-like transposable element 1 (TE1) into the coding region of BnaC3.CCD4 had disrupted its expression in yellow-flowered rapeseed lines. α-Ionone was identified as the major volatile apocarotenoid released from white petals but not from yellow petals. We speculate that BnaC3.CCD4 may use δ- and/or α-carotene as substrates. Four variations, including two CACTA-like TEs (alleles M1 and M4) and two insertion/deletions (INDELs, alleles M2 and M3), were identified in yellow-flowered Brassica oleracea lines. The two CACTA-like TEs were also identified in the coding region of BcaC3.CCD4 in Brassica carinata. However, the two INDELs were not detected in B. napus and B. carinata. We demonstrate that the insertions of TEs in BolC3.CCD4 predated the formation of the two allotetraploids. PMID:25690717

  20. Carotenoid limitation of sexual coloration along an environmental gradient in guppies

    OpenAIRE

    Grether, G. F; Hudon, J; Millie, D. F.

    1999-01-01

    Carotenoids produce most of the brilliant orange and yellow colours seen in animals, but animals cannot synthesize these pigments and must rely on dietary sources. The idea that carotenoids make good signals because they are a scarce limiting resource was proposed two decades ago and has become the leading hypothesis for the role of carotenoids in animal communication. To our knowledge, until now, however, there has been no direct evidence that carotenoids are a limiting resource in nature. W...

  1. Biochemistry and Molecular Biology of Carotenoid Biosynthesis in Chili Peppers (Capsicum spp.)

    OpenAIRE

    María del Rocío Gómez-García; Neftalí Ochoa-Alejo

    2013-01-01

    Capsicum species produce fruits that synthesize and accumulate carotenoid pigments, which are responsible for the fruits’ yellow, orange and red colors. Chili peppers have been used as an experimental model for studying the biochemical and molecular aspects of carotenoid biosynthesis. Most reports refer to the characterization of carotenoids and content determination in chili pepper fruits from different species, cultivars, varieties or genotypes. The types and levels of carotenoids differ be...

  2. Enhancement of Carotenoid Biosynthesis in Transplastomic Tomatoes by Induced Lycopene-to-Provitamin A Conversion

    OpenAIRE

    Apel, W.; R. Bock

    2009-01-01

    Carotenoids are essential pigments of the photosynthetic apparatus and an indispensable component of the human diet. In addition to being potent antioxidants, they also provide the vitamin A precursor beta-carotene. In tomato (Solanum lycopersicum) fruits, carotenoids accumulate in specialized plastids, the chromoplasts. How the carotenoid biosynthetic pathway is regulated and what limits total carotenoid accumulation in fruit chromoplasts is not well understood. Here, we have introduced the ...

  3. Theoretical study on photophysical properties of 3‧-hydroxyechinenone and the effects of interactions with orange carotenoid protein

    Science.gov (United States)

    Otsuka, Miho; Mori, Yukie; Takano, Keiko

    2016-03-01

    3‧-Hydroxyechinenone (3‧-hECN) is a chromophore of the orange carotenoid protein (OCP). Excitation of 3‧-hECN bound to OCP to the S2(11Bu+) state yields an emission characteristic of an intramolecular charge transfer (ICT) state. The present computational results indicate that the S1 state of 3‧-hECN is of the 21Ag- character and slightly gains an ICT character through the mixing with the S2(11Bu+) state when the polyene chain is twisted. Formation of hydrogen bonds with OCP enhances the 21Ag-/11Bu+ mixing and hence the ICT character in the S1 state. Such carotenoid-protein interaction may explain the observation of the ICT emission.

  4. Microscale extraction method for HPLC carotenoid analysis in vegetable matrices

    Directory of Open Access Journals (Sweden)

    Sidney Pacheco

    2014-10-01

    Full Text Available In order to generate simple, efficient analytical methods that are also fast, clean, and economical, and are capable of producing reliable results for a large number of samples, a micro scale extraction method for analysis of carotenoids in vegetable matrices was developed. The efficiency of this adapted method was checked by comparing the results obtained from vegetable matrices, based on extraction equivalence, time required and reagents. Six matrices were used: tomato (Solanum lycopersicum L., carrot (Daucus carota L., sweet potato with orange pulp (Ipomoea batatas (L. Lam., pumpkin (Cucurbita moschata Duch., watermelon (Citrullus lanatus (Thunb. Matsum. & Nakai and sweet potato (Ipomoea batatas (L. Lam. flour. Quantification of the total carotenoids was made by spectrophotometry. Quantification and determination of carotenoid profiles were formulated by High Performance Liquid Chromatography with photodiode array detection. Microscale extraction was faster, cheaper and cleaner than the commonly used one, and advantageous for analytical laboratories.

  5. Noninvasive measurements of carotenoids in bovine udder by reflection spectroscopy

    Science.gov (United States)

    Klein, Julia; Darvin, Maxim E.; Müller, Kerstin E.; Lademann, Jürgen

    2012-10-01

    For a long time, the antioxidative status in cattle has been discussed as an indicator for stress conditions resulting from disease or exertion. Until now, invasive approaches have been necessary to obtain blood samples or biopsy materials and gain insights into the antioxidative status of cattle. Due to these efforts and the costs of the analyses, serial sampling is feasible in an experimental setting, but not for measurements on a routine basis. The present study focuses on the feasibility of an innovative, noninvasive spectroscopic technique that allows in vivo measurements of carotenoids in the skin by reflection spectroscopy. To this end, in a first trial, repeated measurements of the carotenoid concentration of the udder skin were performed on 25 healthy cattle from different breeds. Carotenoid concentrations showed highly significant differences between individual animals (Ptest) differed significantly (P<0.005), with higher concentrations observed in robust cows.

  6. Evaluation of Extraction Methods for the Analysis of Carotenoids for Different Vegetable Matrix

    OpenAIRE

    Stancuta Scrob; Sevastita Muste; Crina Muresan; Anca Farcas; Sonia Socaci; Romina Vlaic

    2013-01-01

    In this study, different solvents were used to achieve the maximum extractibility of total carotenoids. The extracted total carotenoids were estimated using UV- visible spectrophotometer. Carotenoids from vegetable matrix can be used as a food colorant, food additive, cosmetics, antioxidants and nutraceuticals.

  7. The contribution of various foods to intake of vitamin A and carotenoids in the Netherlands

    NARCIS (Netherlands)

    Goldbohm, R.A.; Brants, H.A.M.; Hulshof, K.F.A.M.; Brandt, P.A. van den

    1998-01-01

    This study presents data on dietary intake of specific carotenoids in the Netherlands, based on a recently developed food composition database for carotenoids. Regularly eaten vegetables, the main dietary source of carotenoids, were sampled comprehensively and analysed with modern analytic methods.

  8. Identification of carotenoids from the extremely halophilic archaeon Haloarcula japonica

    Directory of Open Access Journals (Sweden)

    Rie eYatsunami

    2014-03-01

    Full Text Available The carotenoids produced by extremely halophilic archaeon Haloarcula japonica were extracted and identified by their chemical, chromatographic, and spectroscopic characteristics (UV-Vis and mass spectrometry. The composition (mol% was 68.1% bacterioruberin, 22.5% monoanhydrobacterioruberin, 9.3% bisanhydrobacterioruberin, < 0.1% isopentenyldehydrorhodopin, and trace amounts of lycopene and phytoene. The in vitro scavenging capacity of a carotenoid, bacterioruberin, extracted from Ha. japonica cells against 1,1-diphenyl-2-picrylhydrazyl (DPPH radicals was evaluated. The antioxidant capacity of bacterioruberin was much higher than that of β-carotene.

  9. In Situ Observation of Successive Crystallizations and Metastable Intermediates in the Formation of Metal-Organic Frameworks.

    Science.gov (United States)

    Yeung, Hamish H-M; Wu, Yue; Henke, Sebastian; Cheetham, Anthony K; O'Hare, Dermot; Walton, Richard I

    2016-02-01

    Understanding the driving forces controlling crystallization is essential for the efficient synthesis and design of new materials, particularly metal-organic frameworks (MOFs), where mild solvothermal synthesis often allows access to various phases from the same reagents. Using high-energy in situ synchrotron X-ray powder diffraction, we monitor the crystallization of lithium tartrate MOFs, observing the successive crystallization and dissolution of three competing phases in one reaction. By determining rate constants and activation energies, we fully quantify the reaction energy landscape, gaining important predictive power for the choice of reaction conditions. Different reaction rates are explained by the structural relationships between the products and the reactants; larger changes in conformation result in higher activation energies. The methods we demonstrate can easily be applied to other materials, opening the door to a greater understanding of crystallization in general. PMID:26836335

  10. Understanding the Formation Mechanism of Two-Dimensional Atomic Islands on Crystal Surfaces by the Condensing Potential Model

    Science.gov (United States)

    Yin, Cong; Lin, Zheng-Zhe; Li, Min; Tang, Hao

    2016-04-01

    A condensing potential (CP) model was established for predicting the geometric structure of two-dimensional (2D) atomic islands on crystal surfaces. To further verify the CP model, statistical molecular dynamics simulations are performed to investigate the trapping adatom process of atomic island steps on Pt (111). According to the detailed analysis on the adatom trapping process, the CP model should be a universal theory to understand the shape of the 2D atomic islands on crystal surfaces.

  11. Estabilidad del Carotenoide Licopeno en Tomates en Conserva Lycopene Carotenoide Stability in Canned Tomatoes

    Directory of Open Access Journals (Sweden)

    Alicia L Ordóñez

    2009-01-01

    Full Text Available El objetivo de este trabajo fue determinar la estabilidad del carotenoide licopeno durante el proceso de elaboración de conservas de tomates peritas y evaluar la misma durante su almacenamiento como producto terminado. Se trabajó con muestras provenientes de elaboraciones industriales extraídas en distintos puntos del proceso: tomates frescos, en la boquilla de alimentación de la línea; tomate pelado, a la salida de la peladora termofísica y producto terminado a la salida del esterilizador-enfriador, de distintos lotes de elaboración y en tres ocasiones durante la temporada 2007. El producto terminado, envasado en hojalata, fue evaluado durante un año, cada tres meses. El licopeno fue extraído con una mezcla de hexano-acetona-etanol y determinado por espectrofotometría visible a 472nm. Los resultados se analizaron estadísticamente mostrando que la esterilización industrial produce liberación celular del licopeno.The objective of this work was to determine lycopene carotenoid stability during manufacturing process in canned peeled whole tomatoes and during its storage as final product. Samples were taken during industrial manufacturing at different process points: fresh tomatoes when they were feeding to process line, peeled tomatoes from thermophysical peeler and finished product after it passed the cooker-cooler. Samples were obtained from different manufacturing lots at three times during the 2007 harvesting season. Canned tomatoes were analyzed every three months, during one year. Lycopene was extracted with hexane-acetone-ethyl alcohol and measured by spectrophotometry at 472 nm. Statistical analysis of the results shows that industrial sterilization produces cell release of lycopene.

  12. Adsorption, Desorption, Surface Diffusion, Lattice Defect Formation, and Kink Incorporation Processes of Particles on Growth Interfaces of Colloidal Crystals with Attractive Interactions

    Directory of Open Access Journals (Sweden)

    Yoshihisa Suzuki

    2016-07-01

    Full Text Available Good model systems are required in order to understand crystal growth processes because, in many cases, precise incorporation processes of atoms or molecules cannot be visualized easily at the atomic or molecular level. Using a transmission-type optical microscope, we have successfully observed in situ adsorption, desorption, surface diffusion, lattice defect formation, and kink incorporation of particles on growth interfaces of colloidal crystals of polystyrene particles in aqueous sodium polyacrylate solutions. Precise surface transportation and kink incorporation processes of the particles into the colloidal crystals with attractive interactions were observed in situ at the particle level. In particular, contrary to the conventional expectations, the diffusion of particles along steps around a two-dimensional island of the growth interface was not the main route for kink incorporation. This is probably due to the number of bonds between adsorbed particles and particles in a crystal; the number exceeds the limit at which a particle easily exchanges its position to the adjacent one along the step. We also found novel desorption processes of particles from steps to terraces, attributing them to the assistance of attractive forces from additionally adsorbing particles to the particles on the steps.

  13. Stoichiometric complex formation by proliferating cell nuclear antigen (PCNA) and its interacting protein: purification and crystallization of the DNA polymerase and PCNA monomer mutant complex from Pyrococcus furiosus

    International Nuclear Information System (INIS)

    A stable stoichiometric complex of archaeal DNA polymerase with proliferating cell nuclear antigen (PCNA) was formed using a PCNA monomer mutant and the complex was successfully crystallized. Replicative DNA polymerase interacts with processivity factors, the β-subunit of DNA polymerase III or proliferating cell nuclear antigen (PCNA), in order to function with a long template DNA. The archaeal replicative DNA polymerase from Pyrococcus furiosus interacts with PCNA via its PCNA-interacting protein (PIP) motif at the C-terminus. The PCNA homotrimeric ring contains one PIP interacting site on each monomer and since the ring can accommodate up to three molecules simultaneously, formation of a stable stoichiometric complex of PCNA with its interacting protein has been difficult to control in vitro. A stable complex of the DNA polymerase with PCNA, using a PCNA monomer mutant, has been purified and crystallized. The best ordered crystal diffracted to 3.0 Å resolution using synchrotron radiation. The crystals belong to space group P21212, with unit-cell parameters a = 225.3, b = 123.3, c = 91.3 Å

  14. Systematics and anomalies in formation and crystal structures of RScSb and R3Sc2Sb3 rare earth compounds

    International Nuclear Information System (INIS)

    Highlights: • New equiatomic RScSb compounds identified for R = La–Nd, Sm, Gd–Tm, Lu, and Y. • The RScSb compounds crystallize in two different crystal structures. • Lighter R (R = La–Nd, Sm) crystallize with the CeScSi-type (tetragonal tI12, I4/mmm). • Heavier R (R = Gd–Tm, Lu, Y) adopt the CeFeSi-type (tetragonal tP6, P4/nmm). • New R3Sc2Sb3 phases identified for R = Gd–Tm, Lu, Y; β-Yb5Sb3-type (orth. oP32, Pnma). -- Abstract: A systematic study of RScSb (R = rare earth) ternary alloys has been carried out by X-ray diffraction, optical and electron microscopy and microprobe analysis. As a result, the new equiatomic RScSb (R = La–Nd, Sm, Gd–Tm, Lu, Y) compounds have been identified. No formation of equiatomic 1:1:1 phases has been observed for Eu and Yb. It has been found the RScSb compounds crystallize in two different crystal structures. The phases formed by the lighter R (La–Nd, Sm) adopt the CeScSi-type (tetragonal tI12, I4/mmm, an ordered variant of the La2Sb-type), while the ones containing the heavier R (R = Gd–Tm, Lu, Y) crystallize with the CeFeSi-type (tetragonal tP6, P4/nmm, an ordered derivative of the Cu2Sb-type). The latter phases were expected to be dimorphic, thus suggesting they might be polymorphic having the CeScSi-type as the low-temperature form; however, no proof of this was found in the course of the present study. Besides the equiatomic compounds, the R3Sc2Sb3 phases have also been identified. They form from Gd-Tm, Lu, included Y, and crystallize in the β-Yb5Sb3-type (orthorhombic oP32, Pnma). The observed lattice parameters, unit cell volume and volume contraction, for both the series of compounds, decrease on going from La to Lu following the lanthanide contraction trend. First principles calculations pinpoint that the differences in the electronic structure are directly related to the differences in the crystal structures of these compounds

  15. Quenching Capabilities of Long-Chain Carotenoids in Light-Harvesting-2 Complexes from Rhodobacter sphaeroides with an Engineered Carotenoid Synthesis Pathway

    Science.gov (United States)

    2016-01-01

    Six light-harvesting-2 complexes (LH2) from genetically modified strains of the purple photosynthetic bacterium Rhodobacter (Rb.) sphaeroides were studied using static and ultrafast optical methods and resonance Raman spectroscopy. These strains were engineered to incorporate carotenoids for which the number of conjugated groups (N = NC=C + NC=O) varies from 9 to 15. The Rb. sphaeroides strains incorporate their native carotenoids spheroidene (N = 10) and spheroidenone (N = 11), as well as longer-chain analogues including spirilloxanthin (N = 13) and diketospirilloxantion (N = 15) normally found in Rhodospirillum rubrum. Measurements of the properties of the carotenoid first singlet excited state (S1) in antennas from the Rb. sphaeroides set show that carotenoid-bacteriochlorophyll a (BChl a) interactions are similar to those in LH2 complexes from various other bacterial species and thus are not significantly impacted by differences in polypeptide composition. Instead, variations in carotenoid-to-BChl a energy transfer are primarily regulated by the N-determined energy of the carotenoid S1 excited state, which for long-chain (N ≥ 13) carotenoids is not involved in energy transfer. Furthermore, the role of the long-chain carotenoids switches from a light-harvesting supporter (via energy transfer to BChl a) to a quencher of the BChl a S1 excited state B850*. This quenching is manifested as a substantial (∼2-fold) reduction of the B850* lifetime and the B850* fluorescence quantum yield for LH2 housing the longest carotenoids. PMID:27285777

  16. Molecular Factors Controlling Photosynthetic Light Harvesting by Carotenoids

    Czech Academy of Sciences Publication Activity Database

    Polívka, Tomáš; Frank, H.A.

    2010-01-01

    Roč. 43, č. 8 (2010), s. 1125-1134. ISSN 0001-4842 Institutional research plan: CEZ:AV0Z50510513 Keywords : carotenoids * energy transfer * photosynthesis * light-harvesting Subject RIV: BO - Biophysics Impact factor: 21.840, year: 2010

  17. Dark excited states of carotenoids: Consensus and controversy

    Czech Academy of Sciences Publication Activity Database

    Polívka, Tomáš; Sundström, V.

    2009-01-01

    Roč. 477, 1-3 (2009), s. 1-11. ISSN 0009-2614 Institutional research plan: CEZ:AV0Z50510513 Keywords : carotenoids * excited states * relaxation pathways * femtosecond spectroscopy Subject RIV: BO - Biophysics Impact factor: 2.291, year: 2009

  18. Femtosecond carotenoid to retinal energy transfer in xanthorhodopsin

    Czech Academy of Sciences Publication Activity Database

    Polívka, Tomáš; Balashov, S.P.; Chábera, P.; Imasheva, E.S.; Yartsev, A.; Sundström, V.; Lanyi, J.K.

    2009-01-01

    Roč. 96, č. 6 (2009), s. 2268-2277. ISSN 0006-3495 R&D Projects: GA AV ČR IAA608170604 Institutional research plan: CEZ:AV0Z50510513 Keywords : energy transfer * carotenoids * femtosecond spectroscopy Subject RIV: BO - Biophysics Impact factor: 4.390, year: 2009

  19. Photon echo spectroscopy reveals structure-dynamics relationships in carotenoids

    Czech Academy of Sciences Publication Activity Database

    Christensson, N.; Polívka, Tomáš; Yartsev, A.; Pullerits, T.

    2009-01-01

    Roč. 79, č. 24 (2009), s. 1-14. ISSN 1098-0121 Institutional research plan: CEZ:AV0Z50510513 Keywords : electron correlations * energy gap * excited states * carotenoids Subject RIV: BO - Biophysics Impact factor: 3.475, year: 2009

  20. Carotenoids are essential for the assembly of cyanobacterial photosynthetic complexes

    Czech Academy of Sciences Publication Activity Database

    Tóth, T. N.; Chukhutsina, V.; Knoppová, Jana; Komenda, Josef; Kis, M.; Lenart, Z.; Garab, G.; Kovács, L.; Gombos, Z.; van Amerongen, H.

    2015-01-01

    Roč. 1847, č. 10 (2015), s. 1153-1165. ISSN 0005-2728 R&D Projects: GA ČR GBP501/12/G055; GA MŠk LO1416 Institutional support: RVO:61388971 Keywords : Carotenoid deficiency * Cyanobacterial photosynthesis * Phycobilisome Subject RIV: EE - Microbiology, Virology Impact factor: 5.353, year: 2014

  1. Na+-Translocating Rhodopsin from Dokdonia sp. PRO95 Does Not Contain Carotenoid Antenna.

    Science.gov (United States)

    Bertsova, Y V; Arutyunyan, A M; Bogachev, A V

    2016-04-01

    Carotenoid-binding properties of Na+-translocating rhodopsin (NaR) from Dokdonia sp. PRO95 were studied. Carotenoids were extracted from Dokdonia sp. PRO95 cells. It was found that zeaxanthin is the predominant carotenoid of this bacterium. Incubation of recombinant NaR purified from Escherichia coli cells with carotenoids from Dokdonia sp. PRO95 did not result in any changes in optical absorption or circular dichroism spectra, indicating the absence of binding of the carotenoids by NaR. The same results were obtained using salinixanthin as the carotenoid. These data along with genome analysis of Dokdonia sp. PRO95 and other flavobacteria indicate that NaR from Dokdonia sp. PRO95 and possibly the other flavobacterial Na+-translocating rhodopsins do not contain a carotenoid antenna. PMID:27293099

  2. Carotenoids of Sea Angels Clione limacina and Paedoclione doliiformis from the Perspective of the Food Chain

    Directory of Open Access Journals (Sweden)

    Takashi Maoka

    2014-03-01

    Full Text Available Sea angels, Clione limacina and Paedoclione doliiformis, are small, floating sea slugs belonging to Gastropoda, and their gonads are a bright orange-red color. Sea angels feed exclusively on a small herbivorous sea snail, Limacina helicina. Carotenoids in C. limacina, P. doliiformis, and L. helicina were investigated for comparative biochemical points of view. β-Carotene, zeaxanthin, and diatoxanthin were found to be major carotenoids in L. helicina. L. helicina accumulated dietary algal carotenoids without modification. On the other hand, keto-carotenoids, such as pectenolone, 7,8-didehydroastaxanthin, and adonixanthin were identified as major carotenoids in the sea angels C. limacina and P. doliiformis. Sea angels oxidatively metabolize dietary carotenoids and accumulate them in their gonads. Carotenoids in the gonads of sea angels might protect against oxidative stress and enhance reproduction.

  3. Carotenoid metabolic profiling and transcriptome-genome mining reveal functional equivalence among blue-pigmented copepods and appendicularia

    KAUST Repository

    Mojib, Nazia

    2014-06-01

    The tropical oligotrophic oceanic areas are characterized by high water transparency and annual solar radiation. Under these conditions, a large number of phylogenetically diverse mesozooplankton species living in the surface waters (neuston) are found to be blue pigmented. In the present study, we focused on understanding the metabolic and genetic basis of the observed blue phenotype functional equivalence between the blue-pigmented organisms from the phylum Arthropoda, subclass Copepoda (Acartia fossae) and the phylum Chordata, class Appendicularia (Oikopleura dioica) in the Red Sea. Previous studies have shown that carotenoid–protein complexes are responsible for blue coloration in crustaceans. Therefore, we performed carotenoid metabolic profiling using both targeted and nontargeted (high-resolution mass spectrometry) approaches in four different blue-pigmented genera of copepods and one blue-pigmented species of appendicularia. Astaxanthin was found to be the principal carotenoid in all the species. The pathway analysis showed that all the species can synthesize astaxanthin from β-carotene, ingested from dietary sources, via 3-hydroxyechinenone, canthaxanthin, zeaxanthin, adonirubin or adonixanthin. Further, using de novo assembled transcriptome of blue A. fossae (subclass Copepoda), we identified highly expressed homologous β-carotene hydroxylase enzymes and putative carotenoid-binding proteins responsible for astaxanthin formation and the blue phenotype. In blue O. dioica (class Appendicularia), corresponding putative genes were identified from the reference genome. Collectively, our data provide molecular evidences for the bioconversion and accumulation of blue astaxanthin–protein complexes underpinning the observed ecological functional equivalence and adaptive convergence among neustonic mesozooplankton.

  4. Computational crystallization.

    Science.gov (United States)

    Altan, Irem; Charbonneau, Patrick; Snell, Edward H

    2016-07-15

    Crystallization is a key step in macromolecular structure determination by crystallography. While a robust theoretical treatment of the process is available, due to the complexity of the system, the experimental process is still largely one of trial and error. In this article, efforts in the field are discussed together with a theoretical underpinning using a solubility phase diagram. Prior knowledge has been used to develop tools that computationally predict the crystallization outcome and define mutational approaches that enhance the likelihood of crystallization. For the most part these tools are based on binary outcomes (crystal or no crystal), and the full information contained in an assembly of crystallization screening experiments is lost. The potential of this additional information is illustrated by examples where new biological knowledge can be obtained and where a target can be sub-categorized to predict which class of reagents provides the crystallization driving force. Computational analysis of crystallization requires complete and correctly formatted data. While massive crystallization screening efforts are under way, the data available from many of these studies are sparse. The potential for this data and the steps needed to realize this potential are discussed. PMID:26792536

  5. Formation mechanism of the low-frequency locally resonant band gap in the two-dimensional ternary phononic crystals

    Institute of Scientific and Technical Information of China (English)

    Wang Gang; Liu Yao-Zong; Wen Ji-Hong; Yu Dian-Long

    2006-01-01

    The low-frequency band gap and the corresponding vibration modes in two-dimensional ternary locally resonant phononic crystals are restudied successfully with the lumped-mass method. Compared with the work of C. Goffaux and J. Sanchez-Dehesa (Phys. Rev. B 67 14 4301(2003)), it is shown that there exists an error of about 50% in their calculated results of the band structure, and one band is missing in their results. Moreover, the in-plane modes shown in their paper are improper, which results in the wrong conclusion on the mechanism of the ternary locally resonant phononic crystals. Based on the lumped-mass method and better description of the vibration modes according to the band gaps, the locally resonant mechanism in forming the subfrequency gaps is thoroughly analysed. The rule used to judge whether a resonant mode in the phononic crystals can result in a corresponding subfrequency gap is also verified in this ternary case.

  6. Formation of a regular domain structure in TGS–TGS + Cr crystals with a profile impurity distribution

    Energy Technology Data Exchange (ETDEWEB)

    Belugina, N. V., E-mail: alla@ns.crys.ras.ru; Gainutdinov, R. V.; Tolstikhina, A. L.; Ivanova, E. S. [Russian Academy of Sciences, Shubnikov Institute of Crystallography (Russian Federation); Kashevich, I. F. [Vitebsk State University (Belarus); Shut, V. N.; Mozzharov, S. E. [Belarussian Academy of Sciences, Institute of Technical Acoustics (Belarus)

    2015-07-15

    A complex investigation of TGS–TGS + Cr crystals with a profile impurity distribution of chromium ions Cr{sup 3+} has been carried out at the macrolevel (measurement of dielectric properties by the method of nematic liquid crystals) and microlevel (domain structure according to atomic force microscopy data). It is established that periodic doped layers are formed only in individual growth pyramids in the regions where the polarization vector has a nonzero component along the normal to the growth faces rather than throughout the entire crystal volume. The domain configuration at the boundary of growth layers with different impurity compositions has been studied by piezoelectric force microscopy. The static unipolarity of layers with and without chromium impurity is approximately identical, whereas the domain-wall density in doped regions is higher than that in undoped ones by a factor of about 7.

  7. Formation of a regular domain structure in TGS–TGS + Cr crystals with a profile impurity distribution

    International Nuclear Information System (INIS)

    A complex investigation of TGS–TGS + Cr crystals with a profile impurity distribution of chromium ions Cr3+ has been carried out at the macrolevel (measurement of dielectric properties by the method of nematic liquid crystals) and microlevel (domain structure according to atomic force microscopy data). It is established that periodic doped layers are formed only in individual growth pyramids in the regions where the polarization vector has a nonzero component along the normal to the growth faces rather than throughout the entire crystal volume. The domain configuration at the boundary of growth layers with different impurity compositions has been studied by piezoelectric force microscopy. The static unipolarity of layers with and without chromium impurity is approximately identical, whereas the domain-wall density in doped regions is higher than that in undoped ones by a factor of about 7

  8. Formation of 2D photonic crystal bars by simultaneous photoelectrochemical etching of trenches and macropores in silicon

    International Nuclear Information System (INIS)

    Joint electrochemical etching of deep macropores and trenches in n-Si (100) has been studied. After the substrate was removed, regions of a sample, bounded on all sides by a closed contour of through trenches, were extracted from the sample, with narrow bars of a 2D photonic crystal remaining. The influence exerted by the distance between pores and a trench and by the modes of etching and subsequent oxidation on the roughness of the side walls of the structures and also on the size and shape of pores near the trench is analyzed for the example of a photonic crystal with a square lattice of macropores. Conditions are found in which the lattice distortion of the photonic crystal is at a minimum and the side walls of the structure are the smoothest (root-mean-square roughness height ∼60 nm).

  9. H{sub 2}V{sub 3}O{sub 8} single-crystal nanobelts: Hydrothermal preparation and formation mechanism

    Energy Technology Data Exchange (ETDEWEB)

    Chang, K.-H. [Department of Chemical Engineering, National Chung Cheng University, Chia-Yi 621, Taiwan (China); Hu, C.-C. [Department of Chemical Engineering, National Chung Cheng University, Chia-Yi 621, Taiwan (China)], E-mail: cchu@che.nthu.edu.tw

    2007-10-15

    The formation mechanism of highly pure H{sub 2}V{sub 3}O{sub 8} single-crystal nanobelts is clarified in a hydrothermal synthesis process with a specially designed precursor solution containing V{sup 5+} and V{sup 4+} in a fixed ratio of 2/1. This specially designed precursor solution provides an additional merit for the rapid fabrication of highly pure H{sub 2}V{sub 3}O{sub 8} nanobelts through a simple hydrothermal route. During the hydrothermal synthesis process, V{sup 5+} species initially reacts with some V{sup 4+} to form a metastable, whisker-like V{sub 10}O{sub 24} . nH{sub 2}O (n < 12). The V{sup 5+} species dissolved from the whisker-like V{sub 10}O{sub 24} . nH{sub 2}O reacts continuously with residual V{sup 4+} ions in the precursor solution to form seeds of H{sub 2}V{sub 3}O{sub 8} single-crystals. The anisotropic growth of H{sub 2}V{sub 3}O{sub 8} single-crystal nanobelts with length > 10 {mu}m and width between 50 and 150 nm occurs with prolonging the hydrothermal time. Finally, highly pure H{sub 2}V{sub 3}O{sub 8} single-crystal nanobelts are obtained when the hydrothermal time reaches 4 h. The textures of vanadium oxides prepared at different hydrothermal times are systematically compared through X-ray diffraction, transmission electron microscopic and X-ray photoelectron spectroscopic analyses to clarify the synthesis mechanism of H{sub 2}V{sub 3}O{sub 8} single-crystal nanobelts.

  10. Testing the carotenoid trade-off hypothesis in the polychromatic Midas cichlid, Amphilophus citrinellus.

    Science.gov (United States)

    Lin, Susan M; Nieves-Puigdoller, Katherine; Brown, Alexandria C; McGraw, Kevin J; Clotfelter, Ethan D

    2010-01-01

    Many animals use carotenoid pigments derived from their diet for coloration and immunity. The carotenoid trade-off hypothesis predicts that, under conditions of carotenoid scarcity, individuals may be forced to allocate limited carotenoids to either coloration or immunity. In polychromatic species, the pattern of allocation may differ among individuals. We tested the carotenoid trade-off hypothesis in the Midas cichlid, Amphilophus citrinellus, a species with two ontogenetic color morphs, barred and gold, the latter of which is the result of carotenoid expression. We performed a diet-supplementation experiment in which cichlids of both color morphs were assigned to one of two diet treatments that differed only in carotenoid content (beta-carotene, lutein, and zeaxanthin). We measured integument color using spectrometry, quantified carotenoid concentrations in tissue and plasma, and assessed innate immunity using lysozyme activity and alternative complement pathway assays. In both color morphs, dietary carotenoid supplementation elevated plasma carotenoid circulation but failed to affect skin coloration. Consistent with observable differences in integument coloration, we found that gold fish sequestered more carotenoids in skin tissue than barred fish, but barred fish had higher concentrations of carotenoids in plasma than gold fish. Neither measure of innate immunity differed between gold and barred fish, or as a function of dietary carotenoid supplementation. Lysozyme activity, but not complement activity, was strongly affected by body condition. Our data show that a diet low in carotenoids is sufficient to maintain both coloration and innate immunity in Midas cichlids. Our data also suggest that the developmental transition from the barred to gold morph is not accompanied by a decrease in innate immunity in this species. PMID:20151818

  11. Evaluation of carotenoid contents in irradiated buriti (Mauritia flexuosa L.)

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Jaqueline M. da; Coelho, Maysa J.; Lima, Keila S.C.; Lima, Antonio L.S. [Instituto Militar de Engenharia (IME), Rio de Janeiro, RJ (Brazil). Secao de Engenharia Nuclear]. E-mail: maysa@ime.eb.br; Godoy, Ronoel L.O.; Pacheco, Sidney [EMBRAPA Agroindustria de Alimentos, Rio de Janeiro, RJ (Brazil)]. E-mail: ronoel@ctaa.embrapa.br; Ferreira, Rubemar S. [Centro Regional de Ciencias Nucleares do Centro-Oeste CRCN-CO/CNEN, Abadia de Goias, GO (Brazil); E-mail: rferreira@cnen.gov.br

    2007-07-01

    Buriti (Mauritia flexuosa L.), a typical Brazilian fruit, can be found at north, northeast and center-west regions in Brazil. It has a high nutritional value and is considered an excellent source of vitamin A precursors, called carotenoids, showing a majority of {beta}-carotene. It can be used in many regional dishes. In this study, Buriti in natura was treated with gamma irradiation, deriving from a cavity type research irradiator which has a Cs-137 radiation source, with the doses of 0.5 and 1.0 kGy. The objective is to evaluate the irradiation effects on nutritional quality maintenance and conservation of Buriti, focusing in optimizer the processing conditions and increase consumption as a way to fight vitamin A deficiency. Clinical, biological and dietetic studies have indicated that the lack of vitamin A is the main cause of night blindness and xerophthalmia. The use of food irradiation is growing and represents an economic benefit to the agriculture through the reduction of post harvesting losses. The irradiated fruits and the control group were evaluated through the total carotenoids analysis, by spectrophotometry, and the carotenoids (a and b-carotene and luteine) determined by High Performance Liquid Chromatography (HPLC). ANOVA was used to treat the results. The results show that buriti is an excellent source of total carotenoids, with a concentration of 44500 {mu}g/100 g in the pulp (70% of {beta}-carotene). The reduction of carotenoids contents due to the irradiation process does not compromise its nutritional quality that is still very above of recommendations, being the dose of 0.5 kGy more appropriate. (author)

  12. The antioxidant potential of carotenoid extract from Phaffia rhodozyma

    Directory of Open Access Journals (Sweden)

    Anna Gramza-Michałowska

    2010-06-01

    Full Text Available Background. Carotenoids are components playing an important role in biological systems, starting with light protection, immunoenhancement, protection against carcinogens and finishing with antioxidant activity. Food additives market is based mainly on synthetic additives; however, higher consumer awareness has resulted in an increased use of natural substances. One of the potentially antioxidant compounds could be a lipid soluble carotenoid – astaxanthin (xanthophyll, found in the microbial world. The aim of this study was to evaluate the antioxidant potential of carotenoid extract from Phaffia rhodozyma extract. Material and methods. Carotenoids extracted from Phaffia rhodozyma and the astaxanthin standard was selected for the investigations. Antioxidant potential was evaluated by radical scavenging activity (DPPH• and ABTS•+ radicals and in lipid oxidative stability measurements (Rancimat, Oxidograph and Schaal oven tests. Results. It was found that the examined extracts presented a significantly higher ability to scavenge the DPPH• radical in comparison to the ABTS•+ radical. Evaluations of linoleic acid emulsion oxidative stability showed a higher antioxidant effect of the Phaffia rhodozyma extract than that of astaxanthin during 19 h of incubation. That potential however, was not detected in linoleic acid emulsion incubated for 96 h, where both additives accelerated oxidation process. In bulk sunflower oil a protective effect of Phaffia rhodozyma extract was observed. In both Rancimat and Oxidograph tests antioxidant activity measured using the induction period was evaluated. However, results of the Schaal oven test indicated that a 144 h incubation of sunflower oil offered a significantly better protection of the lipid against oxidation when the Phaffia rhodozyma extract was added. Conclusions. On the basis of recorded results it was found that the Phaffia rhodozyma carotenoid extract showed moderate antioxidant properties

  13. Evaluation of carotenoid contents in irradiated buriti (Mauritia flexuosa L.)

    International Nuclear Information System (INIS)

    Buriti (Mauritia flexuosa L.), a typical Brazilian fruit, can be found at north, northeast and center-west regions in Brazil. It has a high nutritional value and is considered an excellent source of vitamin A precursors, called carotenoids, showing a majority of β-carotene. It can be used in many regional dishes. In this study, Buriti in natura was treated with gamma irradiation, deriving from a cavity type research irradiator which has a Cs-137 radiation source, with the doses of 0.5 and 1.0 kGy. The objective is to evaluate the irradiation effects on nutritional quality maintenance and conservation of Buriti, focusing in optimizer the processing conditions and increase consumption as a way to fight vitamin A deficiency. Clinical, biological and dietetic studies have indicated that the lack of vitamin A is the main cause of night blindness and xerophthalmia. The use of food irradiation is growing and represents an economic benefit to the agriculture through the reduction of post harvesting losses. The irradiated fruits and the control group were evaluated through the total carotenoids analysis, by spectrophotometry, and the carotenoids (a and b-carotene and luteine) determined by High Performance Liquid Chromatography (HPLC). ANOVA was used to treat the results. The results show that buriti is an excellent source of total carotenoids, with a concentration of 44500 μg/100 g in the pulp (70% of β-carotene). The reduction of carotenoids contents due to the irradiation process does not compromise its nutritional quality that is still very above of recommendations, being the dose of 0.5 kGy more appropriate. (author)

  14. Analysis of stray grain formation in single crystal CMSX-4 superalloy; Analyse der Bildung von Fehlkoernern in einer einkristallinen CMSX-4-Superlegierung

    Energy Technology Data Exchange (ETDEWEB)

    Chmiela, Bartosz; Sozanska, Maria; Cwajna, Jan [Silesian Univ. of Technology, Katowice (Poland). Dept. of Materials Science; Szeliga, Dariusz [Rzeszow Univ. of Technology (Poland). Dept. of Materials Science; Jarczyk, Jerzy [ALD Vacuum Technologies, Hanau (Germany)

    2013-08-01

    Modern single crystal (SX) turbine blades are fabricated by directional solidification using a grain selector. The grain selection process was investigated by numerical simulation and verified by the experiment. A coupled ProCAST and cellular automaton finite element (CAFE) model was used in this study. According to the latest literature data, we designed the grain selector. Simulation confirmed an optimal grain selection efficiency of the applied selector geometry. The obtained experimental results reveal the possibility of stray grain formation in SX castings with a designed selector, in contrast to the simulation results. (orig.)

  15. Vacuum filtration based formation of liquid crystal films of semiconducting carbon nanotubes and high performance transistor devices

    International Nuclear Information System (INIS)

    In this paper, we report ultra-thin liquid crystal films of semiconducting carbon nanotubes using a simple vacuum filtration process. Vacuum filtration of nanotubes in aqueous surfactant solution formed nematic domains on the filter membrane surface and exhibited local ordering. A 2D fast Fourier transform was used to calculate the order parameters from scanning electron microscopy images. The order parameter was observed to be sensitive to the filtration time demonstrating different regions of transformation namely nucleation of nematic domains, nanotube accumulation and large domain growth.Transmittance versus sheet resistance measurements of such films resulted in optical to dc conductivity of σ opt/σ dc = 9.01 indicative of purely semiconducting nanotube liquid crystal network.Thin films of nanotube liquid crystals with order parameters ranging from S = 0.1–0.5 were patterned into conducting channels of transistor devices which showed high I on/I off ratios from 10–19 800 and electron mobility values μ e = 0.3–78.8 cm2 (V-s)−1, hole mobility values μ h = 0.4–287 cm2 (V-s)−1. High I on/I off ratios were observed at low order parameters and film mass. A Schottky barrier transistor model is consistent with the observed transistor characteristics. Electron and hole mobilities were seen to increase with order parameters and carbon nanotube mass fractions. A fundamental tradeoff between decreasing on/off ratio and increasing mobility with increasing nanotube film mass and order parameter is therefore concluded. Increase in order parameters of nanotubes liquid crystals improved the electronic transport properties as witnessed by the increase in σ dc/σ opt values on macroscopic films and high mobilities in microscopic transistors. Liquid crystal networks of semiconducting nanotubes as demonstrated here are simple to fabricate, transparent, scalable and could find wide ranging device applications. (papers)

  16. Study of 'Redhaven' peach and its white-fleshed mutant suggests a key role of CCD4 carotenoid dioxygenase in carotenoid and norisoprenoid volatile metabolism

    Directory of Open Access Journals (Sweden)

    Tartarini Stefano

    2011-01-01

    Full Text Available Abstract Background Carotenoids are plant metabolites which are not only essential in photosynthesis but also important quality factors in determining the pigmentation and aroma of flowers and fruits. To investigate the regulation of carotenoid metabolism, as related to norisoprenoids and other volatile compounds in peach (Prunus persica L. Batsch., and the role of carotenoid dioxygenases in determining differences in flesh color phenotype and volatile composition, the expression patterns of relevant carotenoid genes and metabolites were studied during fruit development along with volatile compound content. Two contrasted cultivars, the yellow-fleshed 'Redhaven' (RH and its white-fleshed mutant 'Redhaven Bianca' (RHB were examined. Results The two genotypes displayed marked differences in the accumulation of carotenoid pigments in mesocarp tissues. Lower carotenoid levels and higher levels of norisoprenoid volatiles were observed in RHB, which might be explained by differential activity of carotenoid cleavage dioxygenase (CCD enzymes. In fact, the ccd4 transcript levels were dramatically higher at late ripening stages in RHB with respect to RH. The two genotypes also showed differences in the expression patterns of several carotenoid and isoprenoid transcripts, compatible with a feed-back regulation of these transcripts. Abamine SG - an inhibitor of CCD enzymes - decreased the levels of both isoprenoid and non-isoprenoid volatiles in RHB fruits, indicating a complex regulation of volatile production. Conclusions Differential expression of ccd4 is likely to be the major determinant in the accumulation of carotenoids and carotenoid-derived volatiles in peach fruit flesh. More in general, dioxygenases appear to be key factors controlling volatile composition in peach fruit, since abamine SG-treated 'Redhaven Bianca' fruits had strongly reduced levels of norisoprenoids and other volatile classes. Comparative functional studies of peach carotenoid

  17. Tomato carotenoid cleavage dioxygenases 1A and 1B: Relaxed double bond specificity leads to a plenitude of dialdehydes, mono-apocarotenoids and isoprenoid volatiles

    Directory of Open Access Journals (Sweden)

    Andrea Ilg

    2014-01-01

    Full Text Available The biosynthetic processes leading to many of the isoprenoid volatiles released by tomato fruits are still unknown, though previous reports suggested a clear correlation with the carotenoids contained within the fruit. In this study, we investigated the activity of the tomato (Solanum lycopersicum carotenoid cleavage dioxygenase (SlCCD1B, which is highly expressed in fruits, and of its homolog SlCCD1A. Using in vitro assays performed with purified recombinant enzymes and by analyzing products formed by the two enzymes in carotene-accumulating Escherichia coli strains, we demonstrate that SlCCD1A and, to a larger extent, SlCCD1B, have a very relaxed specificity for both substrate and cleavage site, mediating the oxidative cleavage of cis- and all-trans-carotenoids as well as of different apocarotenoids at many more double bonds than previously reported. This activity gives rise to a plenitude of volatiles, mono-apocarotenoids and dialdehyde products, including cis-pseudoionone, neral, geranial, and farnesylacetone. Our results provide a direct evidence for a carotenoid origin of these compounds and point to CCD1s as the enzymes catalyzing the formation of the vast majority of tomato isoprenoid volatiles, many of which are aroma constituents.

  18. Tomato carotenoid cleavage dioxygenases 1A and 1B: Relaxed double bond specificity leads to a plenitude of dialdehydes, mono-apocarotenoids and isoprenoid volatiles

    KAUST Repository

    Ilg, Andrea

    2014-06-25

    The biosynthetic processes leading to many of the isoprenoid volatiles released by tomato fruits are still unknown, though previous reports suggested a clear correlation with the carotenoids contained within the fruit. In this study, we investigated the activity of the tomato (Solanum lycopersicum) carotenoid cleavage dioxygenase (SlCCD1B), which is highly expressed in fruits, and of its homolog SlCCD1A. Using in vitro assays performed with purified recombinant enzymes and by analyzing products formed by the two enzymes in carotene-accumulating Escherichia coli strains, we demonstrate that SlCCD1A and, to a larger extent, SlCCD1B, have a very relaxed specificity for both substrate and cleavage site, mediating the oxidative cleavage of cis- and all-. trans-carotenoids as well as of different apocarotenoids at many more double bonds than previously reported. This activity gives rise to a plenitude of volatiles, mono-apocarotenoids and dialdehyde products, including cis-pseudoionone, neral, geranial, and farnesylacetone. Our results provide a direct evidence for a carotenoid origin of these compounds and point to CCD1s as the enzymes catalyzing the formation of the vast majority of tomato isoprenoid volatiles, many of which are aroma constituents. © 2014 The Authors.

  19. Carotenoid absorption, chylomicron response curves, the influence of β-carotene supplementation on immune function and the measurement of natural killer cell function

    International Nuclear Information System (INIS)

    Absorption of β-carotene from raw, uncooked vegetables can be very low. Particle size of uncooked foods is particularly important; β-carotene absorption from pureed or finely chopped vegetables is considerably higher than from whole or sliced raw vegetables. Cooking procedures (boiling/steaming) improves the chemical extractability of carotenoids from foods and also appears to improve absorption. Dietary fat stimulates bile flow from the gall bladder which facilitates the emulsification of fat and fat soluble dietary components into lipid micelles within the small intestine. Without micelle formation carotenoids are very poorly absorbed. Several studies have shown that the absence of dietary fat or very low fat diets substantially reduces β-carotene absorption in human volunteers. Carotenoid absorption is thought to be a passive process. The assumption is that carotenoids within lipid micelles come into contact with the intestinal epithelial cell membranes and that transport from micelles to the plasma membrane and cytosol of the cell occur together with the transport of fatty acids. β-carotene appears simultaneously in lymph with newly absorbed fat from a meal and thus it is assumed that they move together across the plasma membrane and within the mucosal cell

  20. Hot spot formation and chemical reaction initiation in shocked HMX crystals with nanovoids: a large-scale reactive molecular dynamics study.

    Science.gov (United States)

    Zhou, Tingting; Lou, Jianfeng; Zhang, Yangeng; Song, Huajie; Huang, Fenglei

    2016-07-14

    We report million-atom reactive molecular dynamic simulations of shock initiation of β-cyclotetramethylene tetranitramine (β-HMX) single crystals containing nanometer-scale spherical voids. Shock induced void collapse and subsequent hot spot formation as well as chemical reaction initiation are observed which depend on the void size and impact strength. For an impact velocity of 1 km s(-1) and a void radius of 4 nm, the void collapse process includes three stages; the dominant mechanism is the convergence of upstream molecules toward the centerline and the downstream surface of the void forming flowing molecules. Hot spot formation also undergoes three stages, and the principal mechanism is kinetic energy transforming to thermal energy due to the collision of flowing molecules on the downstream surface. The high temperature of the hot spot initiates a local chemical reaction, and the breakage of the N-NO2 bond plays the key role in the initial reaction mechanism. The impact strength and void size have noticeable effects on the shock dynamical process, resulting in a variation of the predominant mechanisms leading to void collapse and hot spot formation. Larger voids or stronger shocks result in more intense hot spots and, thus, more violent chemical reactions, promoting more reaction channels and generating more reaction products in a shorter duration. The reaction products are mainly concentrated in the developed hot spot, indicating that the chemical reactivity of the hmx crystal is greatly enhanced by void collapse. The detailed information derived from this study can aid a thorough understanding of the role of void collapse in hot spot formation and the chemical reaction initiation of explosives. PMID:27307079

  1. About the mechanism for paramagnetic centers formation under the radiolysis of RbNO{sub 3} and CsNO{sub 3} crystals

    Energy Technology Data Exchange (ETDEWEB)

    Anan’ev, V., E-mail: eprlab@kemsu.ru; Pak, V.

    2014-05-01

    The accumulation of paramagnetic centers – NO{sub 2}{sup ·} and O{sup ·−} in RbNO{sub 3} and CsNO{sub 3} crystals under γ-irradiation at 310 K and their thermal stability has been studied. The values of the initial radiation chemical yield of NO{sub 2}{sup ·} were calculated to be ∼2.5 × 10{sup −2} (100 eV){sup −1} in both nitrates. These values for O{sup ·−} are equal to 0.05 and 0.38 (100 eV){sup −1} for RbNO{sub 3} and CsNO{sub 3}, respectively. The heating of irradiated crystals results in the decay of NO{sub 2}{sup ·} and O{sup ·−} centers with simultaneously appearance of the ozonide ion. The mechanism for paramagnetic centers formation under γ-irradiation of RbNO{sub 3} and CsNO{sub 3} crystals has been discussed.

  2. Accumulation of carotenoids and expression of carotenogenic genes in peach fruit.

    Science.gov (United States)

    Cao, Shifeng; Liang, Minhua; Shi, Liyu; Shao, Jiarong; Song, Chunbo; Bian, Kun; Chen, Wei; Yang, Zhenfeng

    2017-01-01

    To understand better the regulatory mechanism of the carotenoid accumulation, the expression profile of relevant carotenoid genes and metabolites were compared between two peach cultivars with different colors during fruit development. Meanwhile, the change pattern of carotenoid content and expression of carotenoid metabolic genes in peaches after harvest in response to blue light were also investigated. As compared to the yellow fleshed-cultivar 'Jinli', lower carotenoid levels were observed in skin and pulp in white peach cultivar 'Hujing', which might be explained by differentially expression of PpCCD4 gene. With respect to 'Jinli', the carotenoid accumulation during fruit development in fruit skin was partially linked with the transcriptional regulation of PpFPPS, PpGGPS, PpLCYB and PpCHYB. However, in the pulp, the accumulation might be also associated with the increased transcriptions of PpPDS, along with the above four genes. Blue light treatment induced carotenoid accumulation in 'Jinli' peaches during storage. In addition, the treated-fruit displayed higher expression of all the eight genes analysed with a lesser extent on PpCCD4, which suggested that the much more increased carotenoid synthesis rate could result in the higher carotenoid content in blue light-treated fruit. The results presented herein contribute to further elucidating the regulatory mechanism of carotenoid accumulation in peach fruit. PMID:27507458

  3. Utilization of Microemulsions from Rhinacanthus nasutus (L.) Kurz to Improve Carotenoid Bioavailability.

    Science.gov (United States)

    Ho, Nai-Hsing; Inbaraj, Baskaran Stephen; Chen, Bing-Huei

    2016-01-01

    Carotenoids have been known to reduce the risk of several diseases including cancer and cardiovascular. However, carotenoids are unstable and susceptible to degradation. Rhinacanthus nasutus (L.) Kurz (R. nasutus), a Chinese medicinal herb rich in carotenoids, was reported to possess vital biological activities such as anti-cancer. This study intends to isolate carotenoids from R. nasutus by column chromatography, identify and quantify by HPLC-MS, and prepare carotenoid microemulsions for determination of absolute bioavailability in rats. Initially, carotenoid fraction was isolated using 250 mL ethyl acetate poured into an open-column packed with magnesium oxide-diatomaceous earth (1:3, w/w). Fourteen carotenoids including internal standard β-apo-8'-carotenal were resolved within 62 min by a YMC C30 column and gradient mobile phase of methanol-acetonitrile-water (82:14:4, v/v/v) and methylene chloride. Highly stable carotenoid microemulsions were prepared using a mixture of Capryol(TM)90, Transcutol®HP, Tween 80 and deionized water, with the mean particle being 10.4 nm for oral administration and 10.7 nm for intravenous injection. Pharmacokinetic study revealed that the absolute bioavailability of carotenoids in microemulsions and dispersion was 0.45% and 0.11%, respectively, while a much higher value of 6.25% and 1.57% were shown for lutein, demonstrating 4-fold enhancement in bioavailability upon incorporation of R. nasutus carotenoids into a microemulsion system. PMID:27150134

  4. Carotenoids and amphibians: effects on life history and susceptibility to the infectious pathogen, Batrachochytrium dendrobatidis.

    Science.gov (United States)

    Cothran, Rickey D; Gervasi, Stephanie S; Murray, Cindy; French, Beverly J; Bradley, Paul W; Urbina, Jenny; Blaustein, Andrew R; Relyea, Rick A

    2015-01-01

    Carotenoids are considered beneficial nutrients because they provide increased immune capacity. Although carotenoid research has been conducted in many vertebrates, little research has been done in amphibians, a group that is experiencing global population declines from numerous causes, including disease. We raised two amphibian species through metamorphosis on three carotenoid diets to quantify the effects on life-history traits and post-metamorphic susceptibility to a fungal pathogen (Batrachochytrium dendrobatidis; Bd). Increased carotenoids had no effect on survival to metamorphosis in gray treefrogs (Hyla versicolor) but caused lower survival to metamorphosis in wood frogs [Lithobates sylvaticus (Rana sylvatica)]. Increased carotenoids caused both species to experience slower development and growth. When exposed to Bd after metamorphosis, wood frogs experienced high mortality, and the carotenoid diets had no mitigating effects. Gray treefrogs were less susceptible to Bd, which prevented an assessment of whether carotenoids could mitigate the effects of Bd. Moreover, carotenoids had no effect on pathogen load. As one of only a few studies examining the effects of carotenoids on amphibians and the first to examine potential interactions with Bd, our results suggest that carotenoids do not always serve amphibians in the many positive ways that have become the paradigm in other vertebrates. PMID:27293690

  5. Opposing effects of oxidative challenge and carotenoids on antioxidant status and condition-dependent sexual signalling.

    Science.gov (United States)

    Tomášek, Oldřich; Gabrielová, Barbora; Kačer, Petr; Maršík, Petr; Svobodová, Jana; Syslová, Kamila; Vinkler, Michal; Albrecht, Tomáš

    2016-01-01

    Several recent hypotheses consider oxidative stress to be a primary constraint ensuring honesty of condition-dependent carotenoid-based signalling. The key testable difference between these hypotheses is the assumed importance of carotenoids for redox homeostasis, with carotenoids being either antioxidant, pro-oxidant or unimportant. We tested the role of carotenoids in redox balance and sexual signalling by exposing adult male zebra finches (Taeniopygia guttata) to oxidative challenge (diquat dibromide) and manipulating carotenoid intake. As the current controversy over the importance of carotenoids as antioxidants could stem from the hydrophilic basis of commonly-used antioxidant assays, we used the novel measure of in vivo lipophilic antioxidant capacity. Oxidative challenge reduced beak pigmentation but elicited an increase in antioxidant capacity suggesting resource reallocation from signalling to redox homeostasis. Carotenoids counteracted the effect of oxidative challenge on lipophilic (but not hydrophilic) antioxidant capacity, thereby supporting carotenoid antioxidant function in vivo. This is inconsistent with hypotheses proposing that signalling honesty is maintained through either ROS-induced carotenoid degradation or the pro-oxidant effect of high levels of carotenoid-cleavage products acting as a physiological handicap. Our data further suggest that assessment of lipophilic antioxidant capacity is necessary to fully understand the role of redox processes in ecology and evolution. PMID:27000655

  6. Effects of experimental brood size manipulation and gender on carotenoid levels of Eurasian kestrels Falco tinnunculus.

    Directory of Open Access Journals (Sweden)

    Toni Laaksonen

    Full Text Available BACKGROUND: Animals use carotenoid-pigments for coloration, as antioxidants and as enhancers of the immune system. Carotenoid-dependent colours can thus signal individual quality and carotenoids have also been suggested to mediate life-history trade-offs. METHODOLOGY: To examine trade-offs in carotenoid allocation between parents and the young, or between skin coloration and plasma of the parents at different levels of brood demand, we manipulated brood sizes of Eurasian kestrels (Falco tinnunculus. PRINCIPAL FINDINGS: Brood size manipulation had no overall effect on plasma carotenoid levels or skin hue of parents, but female parents had twice the plasma carotenoid levels of males. Males work physically harder than females and they might thus also use more carotenoids against oxidative stress than females. Alternatively, females could be gaining back the carotenoid stores they depleted during egg-laying by eating primarily carotenoid-rich food items during the early nestling stage. Fledglings in enlarged broods had higher plasma carotenoid concentrations than those in reduced broods. This difference was not explained by diet. In light of recent evidence from other species, we suggest it might instead be due to fledglings in enlarged broods having higher testosterone levels, which in turn increased plasma carotenoid levels. The partial cross-foster design of our experiment revealed evidence for origin effects (genetic or maternal on carotenoid levels of fledglings, but no origin-environment interaction. SIGNIFICANCE: These results from wild birds differ from studies in captivity, and thus offer new insights into carotenoid physiology in relation to division of parental care and demands of the brood.

  7. Influence of clusters in melt on the subsequent glass-formation and crystallization of Fe-Si-B metallic glasses

    Institute of Scientific and Technical Information of China (English)

    Shaoxiong Zhou; Bangshao Dong; Rui Xiang; Guangqiang Zhang; Jingyu Qin; Xiufang Bian

    2015-01-01

    The liquid structure of seven representative Fe–Si–B alloys has been investigated by ab initio molecular dynamics simulation focusing on the role of clusters in terms of glass-forming ability (GFA) and crystallization. It is demonstrated that the type of primary phase precipitated from amorphous state under heat treatment is determined by the relative fraction and role of various clusters in melt. The alloy melt shows higher stability and resultantly larger GFA when there is no dominant cluster or several clusters coexist, which explains the different GFAs and crystallization processes at various ratios of Si and B in the Fe–Si–B system. The close correlation among clusters, crystalline phase and GFA is also studied.

  8. Influence of clusters in melt on the subsequent glass-formation and crystallization of Fe–Si–B metallic glasses

    Directory of Open Access Journals (Sweden)

    Shaoxiong Zhou

    2015-04-01

    Full Text Available The liquid structure of seven representative Fe–Si–B alloys has been investigated by ab initio molecular dynamics simulation focusing on the role of clusters in terms of glass-forming ability (GFA and crystallization. It is demonstrated that the type of primary phase precipitated from amorphous state under heat treatment is determined by the relative fraction and role of various clusters in melt. The alloy melt shows higher stability and resultantly larger GFA when there is no dominant cluster or several clusters coexist, which explains the different GFAs and crystallization processes at various ratios of Si and B in the Fe–Si–B system. The close correlation among clusters, crystalline phase and GFA is also studied.

  9. Characterization of carotenoid-protein complexes and gene expression analysis associated with carotenoid sequestration in pigmented cassava (Manihot esculenta Crantz) storage root

    Science.gov (United States)

    Carotenoid-protein complex separation by size exclusion chromatography, protein fractionation by SDS-PAGE, and shotgun PROTEOMICS technology were used to identify and characterize carotenoid associated proteins (CAPs) of chromoplast-enriched suspensions from cassava intense yellow storage root. A no...

  10. Formation of liquid crystal multi-domains with different threshold voltages by varying the surface anchoring energy

    Science.gov (United States)

    Lee, Ji-Hoon; Jin, Huillian; Kim, Jung-Wook; Kim, Ki-Han; Park, Byung Wok; Yoon, Tae-Hoon; Kim, Hoon; Shin, Ki-Chul; Kim, Hee Seop

    2012-09-01

    We propose methods to obtain multi-domains with different threshold voltages for vertically aligned liquid crystal displays without additional transistors or capacitors. We exposed an ultraviolet light through a photomask and spatially varied the surface anchoring energy by partially decomposing the polyimide or inducing the adsorption of reactive monomers. The threshold voltage was reduced with smaller surface anchoring, and the reduction of the threshold could be qualitatively interpreted using a model describing a weak anchoring condition.

  11. The effect of solar radiation on beta-carotene and other carotenoid content in carrot roots

    International Nuclear Information System (INIS)

    The three following cultivars of carrot - Napoli F1, Fantazja, Kazan F1 - were grown in the years 1998-00. The seeds were sown in ridges from the end of April until the beginning of June. Throughout the growth period the total solar radiation was recorded by an automatic system. Every 2 weeks, the leaf area index and the amount of absorbed photosynthetically active radiation (PAR) were calculated. Correlation was found between solar radiation and beta-carotene as well as other carotenoid content in carrot roots. It was found that beta-carotene content depended mainly on the amount of absorbed photosynthetically active radiation by single carrot plants, and not by area unit. Differences in beta-carotene content in carrot cultivars were caused by the time of root formation, rate of beta-carotene production, and total absorbed PAR (PARa)

  12. From surface science to catalysis: The importance of methoxy and formate species on Cu single crystals and industrial catalysts

    Science.gov (United States)

    Bowker, M.; Waugh, K. C.

    2016-08-01

    Early work from the Madix group identified a number of simple surface intermediate species which have proved to be of significance for industrial catalytic processes. Two of these intermediates are the methoxy and formate surface species. We discuss the formation and behavior of these on copper surfaces, and go on to highlight their role in two important industrial reactions, namely methanol synthesis and the selective oxidation of methanol to formaldehyde. The formate is the pivotal intermediate for methanol synthesis and is formed from the reaction of CO2 and H2, whereas it is important to avoid the formation of that intermediate for selective methanol oxidation, which proceeds through dehydrogenation of the methoxy species.

  13. Effects of organic and conventional growth systems on the content of carotenoids in carrot roots, and on intake and plasma status of carotenoids in humans

    DEFF Research Database (Denmark)

    Søltoft, Malene; Bysted, Anette; Madsen, K. H.;

    2011-01-01

    BACKGROUND: The demand for organic food products has increased during the last decades due to their probable health effects, among others. A higher content of secondary metabolites such as carotenoids in organic food products has been claimed, though not documented, to contribute to increased...... health effects of organic foods. The aim was to study the impact of organic and conventional agricultural systems on the content of carotenoids in carrots and human diets. In addition, a human cross-over study was performed, measuring the plasma status of carotenoids in humans consuming diets made from...... crops from these agricultural systems. RESULTS: The content of carotenoids in carrot roots and human diets was not significantly affected by the agricultural production system or year, despite differences in fertilisation strategy and levels. The plasma status of carotenoids increased significantly...

  14. Colorful World of Microbes: Carotenoids and Their Applications

    Directory of Open Access Journals (Sweden)

    Kushwaha Kirti

    2014-01-01

    Full Text Available Microbial cells accumulate pigments under certain culture conditions, which have very important industrial applications. Microorganisms can serve as sources of carotenoids, the most widespread group of naturally occurring pigments. More than 750 structurally different yellow, orange, and red colored molecules are found in both eukaryotes and prokaryotes with an estimated market of $ 919 million by 2015. Carotenoids protect cells against photooxidative damage and hence found important applications in environment, food and nutrition, disease control, and as potent antimicrobial agents. In addition to many research advances, this paper reviews concerns with recent evaluations, applications of microbial pigments, and recommendations for future researches with an understanding of evolution and biosynthetic pathways along with other relevant aspects.

  15. Resonance Raman measurements of carotenoids using light emitting diodes

    CERN Document Server

    Bergeson, S D; Eyring, N J; Fralick, J F; Stevenson, D N; Ferguson, S B

    2008-01-01

    We report on the development of a compact commercial instrument for measuring carotenoids in skin tissue. The instrument uses two light emitting diodes (LEDs) for dual-wavelength excitation and four photomultiplier tubes for multichannel detection. Bandpass filters are used to select the excitation and detection wavelengths. The f/1.3 optical system has high optical throughput and single photon sensitivity, both of which are crucial in LED-based Raman measurements. We employ a signal processing technique that compensates for detector drift and error. The sensitivity and reproducibility of the LED Raman instrument compares favorably to laser-based Raman spectrometers. This compact, portable instrument is used for non-invasive measurement of carotenoid molecules in human skin with a repeatability better than 10%.

  16. Absorption of Carotenoids and Mechanisms Involved in Their Health-Related Properties.

    Science.gov (United States)

    Cervantes-Paz, Braulio; Victoria-Campos, Claudia I; Ornelas-Paz, José de Jesús

    2016-01-01

    Carotenoids participate in the normal metabolism and function of the human body. They are involved in the prevention of several diseases, especially those related to the inflammation syndrome. Their main mechanisms of action are associated to their potent antioxidant activity and capacity to regulate the expression of specific genes and proteins. Recent findings suggest that carotenoid metabolites may explain several processes where the participation of their parent carotenoids was unclear. The health benefits of carotenoids strongly depend on their absorption and transformation during gastrointestinal digestion. The estimation of the 'bioaccessibility' of carotenoids through in vitro models have made possible the evaluation of the effect of a large number of factors on key stages of carotenoid digestion and intestinal absorption. The bioaccessibility of these compounds allows us to have a clear idea of their potential bioavailability, a term that implicitly involves the biological activity of these compounds. PMID:27485232

  17. Analysis on Carotenoids Content and Other Quality Traits of 185 Wheat Varieties

    Institute of Scientific and Technical Information of China (English)

    Jian ZHOU; Yuanyuan WU; Wenyin ZHENG; Wenming ZHANG; Wenshang GUO; Danian YAO

    2015-01-01

    In order to provide the reference of improving the nutritional quality traits in carotenoids and screening its resources of wheat varieties, 185 wheat varieties or lines were selected as materials to test the carotenoids content, lipoxygenase activ-ity, whiteness, yel owness and some other quality traits of whole mil in wheat.The results showed that there were highly significant variations in lipoxygenase activity , carotenoids content, whiteness and yel owness among those sample of wheat vari-eties; carotenoids content was significantly and positively correlated with yel owness. Cluster analysis was performed based on carotenoids content clustered al the vari-eties or lines into three major groups. Additional y, carotenoids were discussed in the application of nutritional quality improvement in wheat.

  18. Microscale extraction method for HPLC carotenoid analysis in vegetable matrices

    OpenAIRE

    Sidney Pacheco; Fernanda Marques Peixoto; Renata Galhardo Borguini; Luzimar da Silva de Mattos do Nascimento; Claudio Roberto Ribeiro Bobeda; Manuela Cristina Pessanha de Araújo Santiago; Ronoel Luiz de Oliveira Godoy

    2014-01-01

    In order to generate simple, efficient analytical methods that are also fast, clean, and economical, and are capable of producing reliable results for a large number of samples, a micro scale extraction method for analysis of carotenoids in vegetable matrices was developed. The efficiency of this adapted method was checked by comparing the results obtained from vegetable matrices, based on extraction equivalence, time required and reagents. Six matrices were used: tomato (Solanum lycopersicum...

  19. Carotenoids and skin coloration in a social raptor

    OpenAIRE

    Blas, Julio; Cabezas, Sonia; Figuerola, Jordi; López, Lidia; Tanferna, Alessandro; Hiraldo, F.; Sergio, Fabrizio; Negro, Juan J.

    2013-01-01

    [IN] The outcome of social and sexual competition in animals is typically mediated through the expression of body traits. Conspicuous characters such as yellow, orange, and red colorations in skin, scales, and feathers are often posited as quality-dependent signals, because such colors are made of dietary carotenoids and their use for signaling conflicts with health functions. Raptors often lack brightly colored feathers but most diurnal species display intense orange and yellow hues in the c...

  20. Identification and Quantification of Major Carotenoids in Some Vegetables

    OpenAIRE

    Jafar M. El-Qudah

    2009-01-01

    An HPLC study of 6 raw vegetables (Okra, green beans, eggplant zucchini, carrot and tomato) most frequently consumed worldwide was carried out to determine their carotenoid composition. The samples were purchased from supermarket in the city of Boston, USA. Neoxanthin, violaxanthin and lutein were contained in all samples except tomato for neoxanthin, carrot and tomato for violaxanthin and carrot for lutein. β-carotene was contained in all samples while α-carotene was contained only...

  1. Resonance Raman detection of carotenoid antioxidants in living human tissue

    OpenAIRE

    Ermakov, Igor V.; M Sharifzadeh; Ermakova, Maia; Gellermann, W.

    2005-01-01

    Increasing evidence points to the beneficial effects of carotenoid antioxidants in the human body. Several studies, for example, support the protective role of lutein and zeaxanthin in the prevention of age-related eye diseases. If present in high concentrations in the macular region of the retina, lutein and zeaxanthin provide pigmentation in this most light sensitive retinal spot, and as a result of light filtering and/or antioxidant action, delay the onset of macular degeneration with incr...

  2. Structures and Properties of Stabilized Vitamin and Carotenoid Dry Powders

    OpenAIRE

    Colombo, Victor E.; Gerber, Francoise

    1991-01-01

    The development of special formulated forms of vitamin and carotenoid dry powders solved most of the technical problems encountered in handling the original pure crystalline or oily compounds. Various procedures to obtain stabilized products have been introduced on an industrial scale for feed , food and pharmaceutical purposes. Proven modes of manufacture of formulated dry powders includes the numerous spraying processes for emulsions, dispersions or solutions, and the production of adsorbat...

  3. Study of RP HPLC Retention Behaviours in Analysis of Carotenoids.

    Science.gov (United States)

    Ligor, M; Kováčová, J; Gadzała-Kopciuch, R M; Studzińska, S; Bocian, Sz; Lehotay, J; Buszewski, B

    2014-01-01

    For determination of selected carotenoids, various types of columns for high-performance liquid chromatography (HPLC) with different properties have been used. The characteristics of the laboratory-used packing material containing monomeric alkyl-bonded phases (C18, C30) and phenyl as well as phenyl-hexyl stationary phases were studied. The retention data of the examined compounds were used to determine the hydrophobicity and silanol activity of stationary phases applied in the study. The presence of the polar and carboxyl groups in the structure of the bonded ligand strongly influences the polarity of the stationary phase. Columns were compared according to methylene selectivity using a series of benzene homologues. The measurements were done using a methanol-water mobile phase. Knowledge of the properties of the applied stationary phase provided the possibility to predict the RP HPLC retention behaviours in analysis of carotenoids including lutein, lycopene and β-carotene. The composition of the mobile phase, the addition of triethylamine and the type of stationary phase had been taken into account in designing the method of carotenoid identification. Also a monolithic column characterised by low hydrodynamic resistance, high porosity and high permeability was applied. The presented results show that the coverage density of the bonded ligands on silica gel packings and length of the linkage strongly influence the carotenoid retention behaviours. In our study, the highest retention parameters for lutein, lycopene and β-carotene were observed for C30 and C18 stationary phase. This effect corresponds with pore size of column packing greater than 100 Å and carbon content higher than 11 %. PMID:25089049

  4. THE CAROTENOID BIOSYNTHETIC PATHWAY: THINKING IN ALL DIMENSIONS

    OpenAIRE

    Shumskaya, Maria; Wurtzel, Eleanore T.

    2013-01-01

    The carotenoid biosynthetic pathway serves manifold roles in plants related to photosynthesis, photoprotection, development, stress hormones, and various volatiles and signalling apocarotenoids. The pathway also produces compounds that impact human nutrition and metabolic products that contribute to fragrance and flavour of food and non-food crops. It is no surprise that the pathway has been a target of metabolic engineering, most prominently in the case of Golden Rice. The future success and...

  5. Influence of orally taken carotenoids on the antioxidative status of the skin, the radical protection function of the skin and the skin lipids

    OpenAIRE

    Friedrich, Annette

    2015-01-01

    In this work, the bioavailability and the antioxidant effect of orally administered carotenoids on the skin were examined. For this purpose different spectroscopic methods were used. A double-blind placebo-controlled study was conducted in 22 subjects over a time period of 20 weeks. The aim of this work was to develop an in vivo method to enable studying the antioxidative and protective effects of naturally occurring antioxidants against radical formation by visible and near infrared (Vi...

  6. Functional characterization of various algal carotenoid ketolases reveals that ketolating zeaxanthin efficiently is essential for high production of astaxanthin in transgenic Arabidopsis

    OpenAIRE

    Zhong, Yu-Juan; Huang, Jun-Chao; Liu, Jin; Li, Yin; Jiang, Yue; Xu, Zeng-Fu; Sandmann, Gerhard; Chen, Feng

    2011-01-01

    Extending the carotenoid pathway to astaxanthin in plants is of scientific and industrial interest. However, expression of a microbial β-carotene ketolase (BKT) that catalyses the formation of ketocarotenoids in transgenic plants typically results in low levels of astaxanthin. The low efficiency of BKTs in ketolating zeaxanthin to astaxanthin is proposed to be the major limitation for astaxanthin accumulation in engineered plants. To verify this hypothesis, several algal BKTs were functionall...

  7. Crystal Structure of α-Galactosidase from Lactobacillus acidophilus NCFM: Insight into Tetramer Formation and Substrate Binding

    DEFF Research Database (Denmark)

    Fredslund, Folmer; Abou Hachem, Maher; Larsen, Rene Jonsgaard;

    2011-01-01

    Lactobacillus acidophilus NCFM is a probiotic bacterium known for its beneficial effects on human health. The importance of α-galactosidases (α-Gals) for growth of probiotic organisms on oligosaccharides of the raffinose family present in many foods is increasingly recognized. Here, the crystal...... structure of α-Gal from L. acidophilus NCFM (LaMel36A) of glycoside hydrolase (GH) family 36 (GH36) is determined by single-wavelength anomalous dispersion. In addition, a 1.58-Å-resolution crystallographic complex with α-d-galactose at substrate binding subsite −1 was determined. LaMel36A has a large N...

  8. Tomato waste: Carotenoids content, antioxidant and cell growth activities.

    Science.gov (United States)

    Stajčić, Sladjana; Ćetković, Gordana; Čanadanović-Brunet, Jasna; Djilas, Sonja; Mandić, Anamarija; Četojević-Simin, Dragana

    2015-04-01

    The carotenoid content, antioxidant and cell growth activities of tomato waste extracts, obtained from five different tomato genotypes, was investigated. High performance liquid chromatography was used to identify and quantify the main carotenoids present in tomato waste extracts. The antioxidant activity of tomato waste extracts was tested using spectrophotometric methods, 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging activity and reducing power assay. The highest DPPH scavenging activity (IC50 = 0.057 mg/ml) was obtained for Bačka extract. The Knjaz extract showed the best reducing power (IC50 = 2.12 mg/ml). Cell growth effects were determined in HeLa, MCF7 and MRC-5 cell lines by sulforhodamine B test. Anti-proliferative effects were observed in all cell lines at higher concentrations (⩾ 0.125 mg/ml). The carotenoid contents exhibited a strong correlation with antioxidant and anti-proliferation activity. The results obtained indicated that tomato waste should be regarded as potential nutraceutic resource and may be used as a functional food ingredient. PMID:25442547

  9. Fast atom bombardment tandem mass spectrometry of carotenoids

    Energy Technology Data Exchange (ETDEWEB)

    van Breeman, R.B. [Univ. of Illinois, Chicago, IL (United States); Schmitz, H.H.; Schwartz, S.J. [North Carolina State Univ., Raleigh, NC (United States)

    1995-02-01

    Positive ion fast atom bombardment (FAB) tandem mass spectrometry (MS-MS) using a double-focusing mass spectrometer with linked scanning at constant B/E and high-energy collisionally activated dissociation (CAD) was used to differentiate 17 different cartenoids, including {beta}-apo-8{prime}- carotenal, astaxanthin, {alpha}-carotene, {beta}-carotene, {gamma}-carotene, {zeta}-carotene, canthaxanthin, {beta}-cryptoxanthin, isozeaxanthin bis (pelargonate), neoxanthin, neurosporene, nonaprene, lutein, lycopene, phytoene, phytofluene, and zeaxanthin. The carotenoids were either synthetic or isolated from plant tissues. The use of FAB ionization minimized degradation or rearrangement of the carotenoid structures due to the inherent thermal instability generally ascribed to these compounds. Instead of protonated molecules, both polar xanthophylls and nonpolar carotenes formed molecular ions, M{sup {center_dot}+}, during FAB ionization. Following collisionally activated dissociation, fragment ions of selected molecular ion precursors showed structural features indicative of the presence of hydroxyl groups, ring systems, ester groups, and aldehyde groups and the extent of aliphatic polyene conjugation. The fragmentation patterns observed in the mass spectra herein may be used as a reference for the structural determination of carotenoids isolated from plant and animal tissues. 18 refs., 4 figs.

  10. Nematode parasites reduce carotenoid-based signalling in male red grouse

    OpenAIRE

    Martínez-Padilla, Jesús; Mougeot, François; Pérez-Rodríguez, Lorenzo; Gary R. Bortolotti

    2007-01-01

    Carotenoids determine the yellow–red colours of many ornaments, which often function as signals of quality. Carotenoid-based signalling may reliably advertise health and should be particularly sensitive to parasite infections. Nematodes are among the commonest parasites of vertebrates, with well-documented negative effects on their hosts. However, to date, little is known about the effects that these parasites may have on carotenoid-based signalling. Tetraonid birds (grouse) exhibit supra-orb...

  11. Carotenoids in Eggs and Plasma of Red-Legged Partridges: Effects of Diet and Reproductive Output

    OpenAIRE

    Bortolotti, Gary R.; Negro, Juan J.; Surai, Peter F; Prieto, Paloma

    2003-01-01

    Carotenoids are important dietary constituents in birds. They serve as pigments and play numerous physiological roles in both the laying hen and developing embryo. However, factors determining the absorption of carotenoids and their allocation to different functions are numerous and complex, and causal relationships are generally poorly known. Our objective was to determine the degree to which carotenoid levels in egg yolks and the plasma of hens were influenced by differences in diet and ...

  12. Theoretical studies of the electrochromic response of carotenoids in photosynthetic membranes.

    OpenAIRE

    Kakitani, T; Honig, B.; Crofts, A R

    1982-01-01

    Molecular orbital calculations are carried out on a number of carotenoids in the presence of an external charge and a constant electric field. The external charge is used to represent the strong permanent field that is believed to polarize carotenoids in photosynthetic membranes and thus to account for their linear response to the transmembrane potential. Our calculations show that the in vitro leads to in vivo spectral shifts of carotenoids (approximately 25 nm) can be produced by a charge i...

  13. The nature and the content of carotenoid pigments from faded leaves of Aesculus hippocastanum L.

    OpenAIRE

    Gino ROSCA; Sanda CRAPATUREANU; Socaciu, Carmen; Gavrila NEAMTU

    1995-01-01

    Faded leaves of Aesculus hippocastanum L. harvested in October and November have a high and various content of carotenoids. The content of lutein and zeaxanthin is much higher in faded leaves than in the green ones, that is why they are recommended as an important natural source for extraction (at an industrial level) of the mentioned carotenoids. Faded leaves have a low biological value, because they have a low content of provitaminic A carotenoids. They have also a low content of hydrocarbo...

  14. Studies on carotenoids and oxidative stability of winter squash seed and soybean oils

    OpenAIRE

    Helmy, H. E.

    1992-01-01

    Winter squash seed and soybean oils were extracted with commercial hexane. Carotenoids and other pigments m the oils were studied using spectrophotometric and thin layer chromatographic analysis. Three types of pigments were identified: carotenoids. mainly lutein and β-carotene, chlorophyll and some unidentified pigments. Carotenoids content were 70, 60, 0 ppm in crude, refined and bleached winter squash seed oil, and 80, 65, 0 ppm in crude, refined and bleached soybean oil respectively. ...

  15. Plasma carotenoid levels in passerines are related to infection by (some parasites

    Directory of Open Access Journals (Sweden)

    JordiFiguerola

    2014-08-01

    Full Text Available Plumage coloration plays an important role in intra and inter-sexual competition in birds. Many of the yellow, orange or red colours present in birds are carotenoid dependent. Carotenoids can not be synthetized de novo by birds and consequently should be obtained through their diet, and access to carotenoids may differ between individuals and species. In addition to ornamentation, carotenoids are important for bird physiology and it has been proposed that a trade-off in their allocation to these two functions occurs. Under this scenario parasites may play a central role in maintaining the honesty of plumage as a signaling system by increasing the demands for carotenoids for infection or damage control and/or by reducing carotenoid absorption in the intestines. We analyzed the relationship between (1 carotenoid concentrations in plasma and (2 blood and intestinal parasite richness and abundance in 22 species of passerines sampled in spring. Loads of different groups of parasites were unrelated so conclusions drawn from examining a particular group of parasites cannot be extrapolated to the whole community of pathogens and parasites inhabiting a host. At intraspecific level plasma carotenoid concentration was negatively related to the richness of intestinal parasites and the abundance of some groups of intestinal parasites, at interspecific level plasma carotenoid concentration was negatively related with the abundance of intestinal parasites. No relationship at intra- nor interpecific level was found between carotenoids and blood parasites. The results suggest that intestinal parasites play an important role in the evolution and maintenance of carotenoid-derived sexually selected ornamentations probably through a negative impact on the uptake of carotenoids at the gut.

  16. Absorption of Vitamin A and Carotenoids by the Enterocyte: Focus on Transport Proteins

    OpenAIRE

    Emmanuelle Reboul

    2013-01-01

    Vitamin A deficiency is a public health problem in most developing countries, especially in children and pregnant women. It is thus a priority in health policy to improve preformed vitamin A and/or provitamin A carotenoid status in these individuals. A more accurate understanding of the molecular mechanisms of intestinal vitamin A absorption is a key step in this direction. It was long thought that β-carotene (the main provitamin A carotenoid in human diet), and thus all carotenoids, were abs...

  17. Potential Role of Carotenoids as Antioxidants in Human Health and Disease

    OpenAIRE

    Joanna Fiedor; Květoslava Burda

    2014-01-01

    Carotenoids constitute a ubiquitous group of isoprenoid pigments. They are very efficient physical quenchers of singlet oxygen and scavengers of other reactive oxygen species. Carotenoids can also act as chemical quenchers undergoing irreversible oxygenation. The molecular mechanisms underlying these reactions are still not fully understood, especially in the context of the anti- and pro-oxidant activity of carotenoids, which, although not synthesized by humans and animals, are also present i...

  18. Serum Carotenoids Reduce Progression of Early Atherosclerosis in the Carotid Artery Wall among Eastern Finnish Men

    OpenAIRE

    Jouni Karppi; Sudhir Kurl; Kimmo Ronkainen; Jussi Kauhanen; Laukkanen, Jari A.

    2013-01-01

    BACKGROUND: Several previous epidemiologic studies have shown that high blood levels of carotenoids may be protective against early atherosclerosis, but results have been inconsistent. We assessed the association between atherosclerotic progression, measured by intima-media thickness of the common carotid artery wall, and serum levels of carotenoids. METHODS: We studied the effect of carotenoids on progression of early atherosclerosis in a population-based study. The association between conce...

  19. Conserved enzymes mediate the early reactions of carotenoid biosynthesis in nonphotosynthetic and photosynthetic prokaryotes.

    OpenAIRE

    G. A. Armstrong; Alberti, M; Hearst, J E

    1990-01-01

    Carotenoids comprise one of the most widespread classes of pigments found in nature. The first reactions of C40 carotenoid biosynthesis proceed through common intermediates in all organisms, suggesting the evolutionary conservation of early enzymes from this pathway. We report here the nucleotide sequence of three genes from the carotenoid biosynthesis gene cluster of Erwinia herbicola, a nonphotosynthetic epiphytic bacterium, which encode homologs of the CrtB, CrtE, and CrtI proteins of Rhod...

  20. Investigations of carotenoids in fungi. III. Fructifications of some species from the genus Suillus

    Directory of Open Access Journals (Sweden)

    Bazyli Czeczuga

    2014-11-01

    Full Text Available Using column and thin-layer chromatography the occurrence of carotenoids and their content was determined in fructifications of 5 species from the genus Suillus. 21 carotenoids were found, among them 3 which had not hitherto been detected in fungi (auroxanthin, 3,4-dihydroxy-α-carotene and myxoxantophyll. Moreover quantitative and qualitative differences were found in the content of carotenoids in fructifications of Boletus luteus which may be of importance in their taxonomy.

  1. Investigations on carotenoids in lichens. XXXII. Carotenoids occurring in the thalli of lichens from Kenya (Equatorial Africa

    Directory of Open Access Journals (Sweden)

    Bazyli Czeczuga

    2014-02-01

    Full Text Available The presence of cartenoids in nineteen species of lichens from Kenya (Equatorial Africa was studied by column and thinlayer chromatography. This investigations revealed the presence of the following carotenoids: neurosporene, α-carotene, β-carotene, rubixanthin, α-cryptoxanthin, β-cryptoxanthin, zeaxanthin, lutein, 3'-epilutein, torularhodin, diatoxanthin, neoxanthin, echinenone, 3'-hydroxyechinenone, canthaxanthin, α-doradexanthin, astaxanthin, β-carotene epoxide, antheraxanthin, lutein epoxide, violaxanthin, mutatoxanthin, flavoxanthin, capsochrome, β-apo-8'-carotenal, β-apo-10'-carotenal and apo-12'-violaxanthal. Five of these, torularhodin, 3'-hydroxyechinenone, capsochrome, β-apo-8'-carotenal and β-apo-10'-carotenal, are reported for the first time from lichens. The total carotenoid content of the material ranged from 15.88 (Pyxine cocoes to 135.44 µg g-1 dry weight (Telaschistes chrysophthalmus.

  2. Resonant Raman detectors for noninvasive assessment of carotenoid antioxidants in human tissue

    Science.gov (United States)

    Gellermann, Werner; Sharifzadeh, Mohsen; Ermakova, Maia R.; Ermakov, Igor V.; Bernstein, P. S.

    2003-07-01

    Carotenoid antioxidants form an important part of the human body's anti-oxidant system and are thought to play an important role in disease prevention. Studies have shown an inverse correlation between high dietary intake of carotenoids and risk of certain cancers, heart disease and degenerative diseases. For example, the carotenoids lutein and zeaxanthin, which are present in high concentrations in the human retina, are thought to prevent age-related macular degeneration, the leading cause of blindness in the elderly in the Western world. We have developed various clinical prototype instruments, based on resonance Raman spectroscopy, that are able to measure carotenoid levels directly in the tissue of interest. At present we use the Raman technology to quantify carotenoid levels in the human retina, in skin, and in the oral cavity. We use resonant excitation of the π-conjugated molecules in the visible wavelength range and detect the molecules' carbon-carbon stretch frequencies. The spectral properties of the various carotenoids can be explored to selectively measure in some cases individual carotenoid species linked ot the prevention of cancer, in human skin. The instrumentation involves home-built, compact, high-throughput Raman systems capable of measuring physiological carotenoid concentrations in human subjects rapidly and quantitatively. The instruments have been demonstrated for field use and screening of tissue carotenoid status in large populations. In Epidemiology, the technology holds promise as a novel, noninvasive and objective biomarker of fruit and vegetable uptake.

  3. The nature and the content of carotenoid pigments from faded leaves of Aesculus hippocastanum L.

    Directory of Open Access Journals (Sweden)

    Gino ROSCA

    1995-08-01

    Full Text Available Faded leaves of Aesculus hippocastanum L. harvested in October and November have a high and various content of carotenoids. The content of lutein and zeaxanthin is much higher in faded leaves than in the green ones, that is why they are recommended as an important natural source for extraction (at an industrial level of the mentioned carotenoids. Faded leaves have a low biological value, because they have a low content of provitaminic A carotenoids. They have also a low content of hydrocarbon carotenoids, but a high hydroxylic and epoxydic content.

  4. Generation of structurally novel short carotenoids and study of their biological activity.

    Science.gov (United States)

    Kim, Se H; Kim, Moon S; Lee, Bun Y; Lee, Pyung C

    2016-01-01

    Recent research interest in phytochemicals has consistently driven the efforts in the metabolic engineering field toward microbial production of various carotenoids. In spite of systematic studies, the possibility of using C30 carotenoids as biologically functional compounds has not been explored thus far. Here, we generated 13 novel structures of C30 carotenoids and one C35 carotenoid, including acyclic, monocyclic, and bicyclic structures, through directed evolution and combinatorial biosynthesis, in Escherichia coli. Measurement of radical scavenging activity of various C30 carotenoid structures revealed that acyclic C30 carotenoids showed higher radical scavenging activity than did DL-α-tocopherol. We could assume high potential biological activity of the novel structures of C30 carotenoids as well, based on the neuronal differentiation activity observed for the monocyclic C30 carotenoid 4,4'-diapotorulene on rat bone marrow mesenchymal stem cells. Our results demonstrate that a series of structurally novel carotenoids possessing biologically beneficial properties can be synthesized in E. coli. PMID:26902326

  5. Biochemistry and molecular biology of carotenoid biosynthesis in chili peppers (Capsicum spp.).

    Science.gov (United States)

    Gómez-García, María del Rocío; Ochoa-Alejo, Neftalí

    2013-01-01

    Capsicum species produce fruits that synthesize and accumulate carotenoid pigments, which are responsible for the fruits' yellow, orange and red colors. Chili peppers have been used as an experimental model for studying the biochemical and molecular aspects of carotenoid biosynthesis. Most reports refer to the characterization of carotenoids and content determination in chili pepper fruits from different species, cultivars, varieties or genotypes. The types and levels of carotenoids differ between different chili pepper fruits, and they are also influenced by environmental conditions. Yellow-orange colors of chili pepper fruits are mainly due to the accumulation of α- and β-carotene, zeaxanthin, lutein and β-cryptoxanthin. Carotenoids such as capsanthin, capsorubin and capsanthin-5,6-epoxide confer the red colors. Chromoplasts are the sites of carotenoid pigment synthesis and storage. According to the most accepted theory, the synthesis of carotenoids in chili peppers is controlled by three loci: c1, c2 and y. Several enzymes participating in carotenoid biosynthesis in chili pepper fruits have been isolated and characterized, and the corresponding gene sequences have been reported. However, there is currently limited information on the molecular mechanisms that regulate this biosynthetic pathway. Approaches to gain more knowledge of the regulation of carotenoid biosynthesis are discussed. PMID:24065101

  6. Biochemistry and Molecular Biology of Carotenoid Biosynthesis in Chili Peppers (Capsicum spp.

    Directory of Open Access Journals (Sweden)

    María del Rocío Gómez-García

    2013-09-01

    Full Text Available Capsicum species produce fruits that synthesize and accumulate carotenoid pigments, which are responsible for the fruits’ yellow, orange and red colors. Chili peppers have been used as an experimental model for studying the biochemical and molecular aspects of carotenoid biosynthesis. Most reports refer to the characterization of carotenoids and content determination in chili pepper fruits from different species, cultivars, varieties or genotypes. The types and levels of carotenoids differ between different chili pepper fruits, and they are also influenced by environmental conditions. Yellow-orange colors of chili pepper fruits are mainly due to the accumulation of α- and β-carotene, zeaxanthin, lutein and β-cryptoxanthin. Carotenoids such as capsanthin, capsorubin and capsanthin-5,6-epoxide confer the red colors. Chromoplasts are the sites of carotenoid pigment synthesis and storage. According to the most accepted theory, the synthesis of carotenoids in chili peppers is controlled by three loci: c1, c2 and y. Several enzymes participating in carotenoid biosynthesis in chili pepper fruits have been isolated and characterized, and the corresponding gene sequences have been reported. However, there is currently limited information on the molecular mechanisms that regulate this biosynthetic pathway. Approaches to gain more knowledge of the regulation of carotenoid biosynthesis are discussed.

  7. Enhancement of carotenoid biosynthesis in transplastomic tomatoes by induced lycopene-to-provitamin A conversion.

    Science.gov (United States)

    Apel, Wiebke; Bock, Ralph

    2009-09-01

    Carotenoids are essential pigments of the photosynthetic apparatus and an indispensable component of the human diet. In addition to being potent antioxidants, they also provide the vitamin A precursor beta-carotene. In tomato (Solanum lycopersicum) fruits, carotenoids accumulate in specialized plastids, the chromoplasts. How the carotenoid biosynthetic pathway is regulated and what limits total carotenoid accumulation in fruit chromoplasts is not well understood. Here, we have introduced the lycopene beta-cyclase genes from the eubacterium Erwinia herbicola and the higher plant daffodil (Narcissus pseudonarcissus) into the tomato plastid genome. While expression of the bacterial enzyme did not strongly alter carotenoid composition, expression of the plant enzyme efficiently converted lycopene, the major storage carotenoid of the tomato fruit, into provitamin A (beta-carotene). In green leaves of the transplastomic tomato plants, more lycopene was channeled into the beta-branch of carotenoid biosynthesis, resulting in increased accumulation of xanthophyll cycle pigments and correspondingly reduced accumulation of the alpha-branch xanthophyll lutein. In fruits, most of the lycopene was converted into beta-carotene with provitamin A levels reaching 1 mg per g dry weight. Unexpectedly, transplastomic tomatoes also showed a >50% increase in total carotenoid accumulation, indicating that lycopene beta-cyclase expression enhanced the flux through the pathway in chromoplasts. Our results provide new insights into the regulation of carotenoid biosynthesis and demonstrate the potential of plastids genome engineering for the nutritional enhancement of food crops. PMID:19587100

  8. Evaluation of antigenotoxic effects of carotenoids from green algae Chlorococcum humicola using human lymphocytes

    Institute of Scientific and Technical Information of China (English)

    Bhagavathy S; Sumathi P

    2012-01-01

    Objective:To identify the available phytochemicals and carotenoids in the selected green algae and evaluate the potential genotoxic/antigenotoxic effect using lymphocytes. Methods:Organic solvent extracts of Chlorococcum humicola (C. humicola) were used for the phytochemical analysis. The available carotenoids were assessed by HPLC, and LC-MS analysis. The genotoxicity was induced by the benzo(a)pyrene in the lymphocyte culture, the genotoxic and antigenotoxic effects of algal carotenoids with and without genotoxic inducer were evaluated by chromosomal aberration (CA), sister chromatid exchange (SCE) and micronucleus assay (MN). Results: The results of the analysis showed that the algae were rich in carotenoids and fatty acids. In the total carotenoids lutein,β-carotene and α-carotene were found to be present in higher concentration. The frequency of CA and SCE increased by benzo(a)pyrene were significantly decreased by the carotenoids (P<0.05 for CA, P<0.001 for SCE). The MN frequencies of the cells were significantly decreased by the treatment with carotenoids when compared with the positive controls (P<0.05). Conclusions:The findings of the present study demonstrate that, the green algae C. humicola is a rich source of bioactive compounds especially carotenoids which effectively fight against environmental genotoxic agents, the carotenoids itself is not a genotoxic substance and should be further considered for its beneficial effects.

  9. An R2R3-MYB transcription factor regulates carotenoid pigmentation in Mimulus lewisii flowers.

    Science.gov (United States)

    Sagawa, Janelle M; Stanley, Lauren E; LaFountain, Amy M; Frank, Harry A; Liu, Chang; Yuan, Yao-Wu

    2016-02-01

    Carotenoids are yellow, orange, and red pigments that contribute to the beautiful colors and nutritive value of many flowers and fruits. The structural genes in the highly conserved carotenoid biosynthetic pathway have been well characterized in multiple plant systems, but little is known about the transcription factors that control the expression of these structural genes. By analyzing a chemically induced mutant of Mimulus lewisii through bulk segregant analysis and transgenic experiments, we have identified an R2R3-MYB, Reduced Carotenoid Pigmentation 1 (RCP1), as the first transcription factor that positively regulates carotenoid biosynthesis during flower development. Loss-of-function mutations in RCP1 lead to down-regulation of all carotenoid biosynthetic genes and reduced carotenoid content in M. lewisii flowers, a phenotype recapitulated by RNA interference in the wild-type background. Overexpression of this gene in the rcp1 mutant background restores carotenoid production and, unexpectedly, results in simultaneous decrease of anthocyanin production in some transgenic lines by down-regulating the expression of an activator of anthocyanin biosynthesis. Identification of transcriptional regulators of carotenoid biosynthesis provides the 'toolbox' genes for understanding the molecular basis of flower color diversification in nature and for potential enhancement of carotenoid production in crop plants via genetic engineering. PMID:26377817

  10. Tea aroma formation

    Directory of Open Access Journals (Sweden)

    Chi-Tang Ho

    2015-03-01

    Full Text Available Besides water, tea is one of the most popular beverages around the world. The chemical ingredients and biological activities of tea have been summarized recently. The current review summarizes tea aroma compounds and their formation in green, black, and oolong tea. The flavor of tea can be divided into two categories: taste (non-volatile compounds and aroma (volatile compounds. All of these aroma molecules are generated from carotenoids, lipids, glycosides, etc. precursors, and also from Maillard reaction. In the current review, we focus on the formation mechanism of main aromas during the tea manufacturing process.

  11. Artistic Crystal Creations

    Science.gov (United States)

    Lange, Catherine

    2008-01-01

    In this inquiry-based, integrative art and science activity, Grade 5-8 students use multicolored Epsom salt (magnesium sulfate) crystallizing solutions to reveal beautiful, cylindrical, 3-dimensional, needle-shaped structures. Through observations of the crystal art, students analyze factors that contribute to crystal size and formation, compare…

  12. Wavelength Dependence of Laser-Induced Bulk Damage Morphology in KDP Crystal: Determination of the Damage Formation Mechanism

    Institute of Scientific and Technical Information of China (English)

    HU Guo-Hang; ZHAO Yuan-An; LI Da-Wei; XIAO Qi-Ling

    2012-01-01

    Wet etch process is applied to expose the bulk damage sites in KDP crystals to the surface for the examination by scanning electron microscopy (SEM) and optical microscopy.The damage sites induced by 1064 nm laser consist of three distinct regions:a core,an outer region of modified material,and some oriented cracks.Laser irradiated with 355 nm results in an increase of damage density,a decrease of core diameter and,rarely,occurrence of the crack.WavelengKey Laboratory of Materials for High Power Laser,Shanghai Institute of Optics and Fine Mechanics Chinese Academy of Sciences,Shanghai 201800th dependence of the damage feature suggests that a repulsive force exists among the adjacent plasmas,which prevents further expansion of plasma and decreases the size of plasma. The deposited energy absorbed by the smaller plasma may not be able to generate the crack.

  13. Spontaneous helix formation in non-chiral bent-core liquid crystals with fast linear electro-optic effect

    Science.gov (United States)

    Sreenilayam, Sithara P.; Panarin, Yuri P.; Vij, Jagdish K.; Panov, Vitaly P.; Lehmann, Anne; Poppe, Marco; Prehm, Marko; Tschierske, Carsten

    2016-05-01

    Liquid crystals (LCs) represent one of the foundations of modern communication and photonic technologies. Present display technologies are based mainly on nematic LCs, which suffer from limited response time for use in active colour sequential displays and limited image grey scale. Herein we report the first observation of a spontaneously formed helix in a polar tilted smectic LC phase (SmC phase) of achiral bent-core (BC) molecules with the axis of helix lying parallel to the layer normal and a pitch much shorter than the optical wavelength. This new phase shows fast (~30 μs) grey-scale switching due to the deformation of the helix by the electric field. Even more importantly, defect-free alignment is easily achieved for the first time for a BC mesogen, thus providing potential use in large-scale devices with fast linear and thresholdless electro-optical response.

  14. Accelerated rogue waves generated by soliton fusion at the advanced stage of supercontinuum formation in photonic crystal fibers

    CERN Document Server

    Driben, Rodislav

    2012-01-01

    Soliton fusion is a fascinating and delicate phenomenon that manifests itself in optical fibers in case of interaction between co-propagating solitons with small temporal and wavelengths separation. We show that the mechanism of acceleration of trailing soliton by dispersive waves radiated from the preceding one provides necessary conditions for soliton fusion at the advanced stage of supercontinuum generation in photonic crystal fibers. As a result of fusion large intensity robust light structures arise and propagate over significant distances. In presence of small random noise the delicate condition for the effective fusion between solitons can easily be broken, making the fusion induced giant waves a rare statistical event. Thus oblong-shaped giant accelerated waves become excellent candidates for optical rogue waves.

  15. Effect of Mo addition on the crystal texture and deformation twin formation in Zr-based alloys

    International Nuclear Information System (INIS)

    The effect of Mo on the crystal texture of Zr-Nb and Zr-Nb-Mo alloys was studied. Molybdenum addition reduced the average sizes of the equiaxed α grains and the packets considerably. In the Zr-Nb alloy specimens free of Mo, the intensity of the normal basal texture increased with the initial grain size, which was attributed to the enhanced probability of twinning in coarse grains. Molybdenum also reduced the intensity of the normal basal texture of the Zr alloys, indicating a possible change in the mode of deformation caused by Mo addition. Moreover, the texture shift of the Zr alloys from ND-TD to ND-RD during annealing heat treatment was accelerated by Mo addition. Weakening of the normal basal texture in the cold-worked Mo-containing alloy, therefore, was attributed to the microstructural refinement and the change in the deformation mode

  16. Atomic force microscopy studies on growth mechanisms and defect formations on {l_brace}110{r_brace} faces of cadmium mercury thiocyanate crystals

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, X.N.; Xu, D.; Yuan, D.R.; Sun, D.L.; Lu, M.K.; Zhang, G.H.; Guo, S.Y. [Shandong Univ., Jinan, SD (China). Inst. of Crystal Materials

    2001-07-01

    Growth mechanisms and defect formations on {l_brace}110{r_brace} faces of cadmium mercury thiocyanate crystals grown at 30 C ({sigma} = 0.24) were investigated by using atomic force microscopy (AFM). It was found that, under this condition, spiral dislocation controlled mechanism and 2D nucleation mechanism operates simultaneously and equally during growth, which is completely different from the traditional 2D nucleation and dislocation source controlled mechanisms. A number of 2D nucleus are formed at the large step terraces generated by dislocation sources, leading to the unequal growth rates of the elementary steps and thereby ''step bunches'' are caused. Various defects are formed under this growth condition, which is assumed to result from the incongruence between the steps generated by different sources. A new kind of 2D defect, corresponding to one growth layer in height, was observed for the first time. (orig.)

  17. Distinguishing crystal-like amyloid fibrils and glass-like amorphous aggregates from their kinetics of formation

    OpenAIRE

    Yoshimura, Yuichi; Lin, Yuxi; Yagi, Hisashi; Lee, Young-Ho; Kitayama, Hiroki; Sakurai, Kazumasa; So, Masatomo; OGI, Hirotsugu; Naiki, Hironobu; Goto, Yuji

    2012-01-01

    Amyloid fibrils and amorphous aggregates are two types of aberrant aggregates associated with protein misfolding diseases. Although they differ in morphology, the two forms are often treated indiscriminately. β2-microglobulin (β2m), a protein responsible for dialysis-related amyloidosis, forms amyloid fibrils or amorphous aggregates depending on the NaCl concentration at pH 2.5. We compared the kinetics of their formation, which was monitored by measuring thioflavin T fluorescence, light scat...

  18. Simulation of stray grain formation at the platform during Ni-base single crystal superalloy DD403 casting

    Directory of Open Access Journals (Sweden)

    Si-feng Gao

    2015-03-01

    Full Text Available The mechanism of stray grain formation at the platform of turbine blade simulator and the effect of withdrawal rate (V on the stray grain phenomenon have been investigated using a macro-scale ProCAST coupled with a 3D Cellular Automaton Finite Element (CAFE model. The results indicate that the stray grains nucleate at the edges of platform at V =150 μm·s-1 and 200 μm·s-1. Using ProCAST computer simulation software, it was proven that the stray grain formation is significantly dependent on the undercooling and the temperature field distribution in the platform. The macroscopic curvature of the liquidus isotherm becomes markedly concave with an increase in the withdrawal rate. The probability of stray grain formation at the edges of platform can be increased by increasing the withdrawal rate in the range of 70 μm·s-1 to 200 μm·s-1.

  19. Slow positrons in metal single crystals. I. Positronium formation at Ag(100), Ag(111), and Cu(111) surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Lynn, K.G.; Welch, D.O.

    1980-07-01

    Monoenergetic positrons, with an incident energy of 0 --5 keV, were focused onto Ag(100), Ag(111), and Cu(111) surfaces with submonolayer contamination, and positronium formation was studied as a function of sample temperature from 300 to 1200 K. The data were fitted with a simple positron diffusion model including surface and vacancy trapping, assuming that positronium is formed only at the surface. The formation of part of the positronium fraction is found to be a temperature-activated process which is identified as detrapping from a surface state, and an estimate of the binding energy in this trap is deduced. The diffusion length is found to be only slightly temperature dependent between room temperature and the onset of vacancy trapping. At the higher sample temperatures positron trapping at thermally generated vacancies is observed by the decrease in the positron diffusion length at the higher incident voltages. A vacancy formation energy is extracted from the data and is generally found to be lower than the values obtained from bulk measurements.

  20. Influence of synthesis conditions on crystal formation and electrochemical properties of TiO2(B) particles as anode materials for lithium-ion batteries

    International Nuclear Information System (INIS)

    TiO2(B) particles as the anode material for lithium-ion batteries were synthesized from three kinds of layered alkali titanates Na2Ti3O7, K2Ti4O9 and Cs2Ti5O11 via H+ ion-exchange followed by heating under several conditions in order to clarify the effect of synthesis conditions on crystal formation and electrochemical properties. Phase formation and crystal structure were analyzed by X-ray diffraction, inductively coupled plasma analysis, and transmission electron microscopy. Reducing of residual alkali cations in the intermediates with ion-exchanging for 2 weeks led to relative high crystallinity which is suitable for smooth migration of lithium ions and has low reactivity with a practical electrolyte. The primitive cell volume of TiO2(B) increased with decreasing heat-treatment temperature of the intermediates. A primitive cell volume of 0.300 nm3 in TiO2(B) structure, which was successfully obtained from the precursor K2Ti4O9 by heating the intermediate at 350 °C for 2 h, causes an expanding of the lithium pathways and storage sites and had a high reversible capacity of 253.1 mA h g−1 close to that of TiO2(B) nanopaticles. This TiO2(B) also showed good cycle performance with the reversible capacity after 200 cycles remaining 95% of the initial capacity, using a practical electrolyte such as LiPF6 in a solution of ethylene carbonate and diethyl carbonate. Consequently, synthesis conditions of H+ ion-exchange time and heat-treatment temperature should be carefully optimized to obtain the large reversible capacity and stable cycle performance of TiO2(B) synthesized from the layered alkali titanates via the H+ ion-exchange process

  1. Carotenoids production: microorganisms as source of natural dyes Produção de carotenoides: microrganismos como fonte de pigmentos naturais

    Directory of Open Access Journals (Sweden)

    Eunice Valduga

    2009-01-01

    Full Text Available Carotenoids are natural dyes synthesized by plants, algae and microorganisms. Application in many sectors can be found, as food dyeing and supplementation, pharmaceuticals, cosmetics and animal feed. Recent investigations have shown their ability to reduce the risks for many degenerative diseases like cancer, heart diseases, cataract and macular degeneration. An advantage of microbial carotenoids is the fact that the cultivation in controlled conditions is not dependent of climate, season or soil composition. In this review the advances in bio-production of carotenoids are presented, discussing the main factors that influence the microbial production of these dyes in different systems.

  2. Cloning and comparative analysis of carotenoid β-hydroxylase genes provides new insights into carotenoid metabolism in tetraploid (Triticum turgidum ssp. durum) and hexaploid (Triticum aestivum) wheat grains

    OpenAIRE

    Qin, X.; Zhang, W.; Dubcovsky, J; Tian, L.

    2012-01-01

    Carotenoid β-hydroxylases attach hydroxyl groups to the β-ionone rings (β-rings) of carotenoid substrates, resulting in modified structures and functions of carotenoid molecules. We cloned and characterized two genes (each with three homeologs), HYD1 and HYD2, which encode β-hydroxylases in wheat. The results from bioinformatic and nested degenerate PCR analyses collectively suggest that HYD1 and HYD2 may represent the entire complement of non-heme di-iron β-hydroxylases in wheat. The homeolo...

  3. Composição de carotenoides em canistel (Pouteria campechiana (Kunth Baehni Carotenoids composition of canistel (Pouteria campechiana (Kunth Baehni

    Directory of Open Access Journals (Sweden)

    Tânia da Silveira Agostini Costa

    2010-09-01

    Full Text Available O canistel (P. campechiana é uma fruta nativa da América Central e México, ainda pouco conhecida no Brasil. Apresenta uma polpa amarelo-alaranjada, rica em carotenoides, que tem despertado interesse como potencial de vitamina A. O objetivo deste trabalho foi determinar o teor de carotenoides e o valor provitamina A na polpa de canistel, assim como os teores de umidade e lipídeos na polpa e na semente. Os carotenoides foram separados por cromatografia em coluna aberta. O conteúdo de carotenoides totais foi de 226 ± 4 μg/g. Violaxantina e neoxantina foram os carotenóides predominantes, somando 196 ± 5 μg/g. seguidos por zetacaroteno, betacaroteno 5,6-epóxido, betacaroteno e fitoflueno. A semente foi a parte do fruto que apresentou maior teor de lipídeos totais, com 4,6 ± 0,2 %, e a polpa, 0,61 ± 0,03 %. Os resultados indicam que o canistel apresenta teores de carotenóides totais muito elevados e pode ser considerado uma boa fonte de provitamina A (59 ± 6 RAE/100g, se comparado com outras frutas normalmente consumidas. No entanto, os principais carotenoides encontrados em sua polpa são destituídos de atividade provitamina A.Canistel (Pouteria campechiana is a native fruit from Central America and Mexico. This fruit still not known in Brazil, presents an orange-yellow pulp rich in carotenoids, which has attracted interest as a potential source of vitamin A. The purpose of this study was to determine the carotenoids content and pro-vitamin A values in the pulp of canistel, as well as the percentage of moisture and lipids in the pulp and seeds. Carotenoids were separated by open column chromatography. The content of total carotenoids was 226 ± 4 μg/g. Violaxantin and neoxantin were the predominant carotenoids with 196 ± 5 μg/g followed by zeta-carotene, beta-carotene 5,6-epoxide, beta-carotene and phytofluene. The seeds presented higher levels of total lipids with 4.6 ± 0.2 %, while pulp had 0.61 ± 0.03 % of total lipid. These

  4. Composição de carotenoides em canistel (Pouteria campechiana (Kunth) Baehni) Carotenoids composition of canistel (Pouteria campechiana (Kunth) Baehni)

    OpenAIRE

    Tânia da Silveira Agostini Costa; Daniele Cristina Wondracek; Renata Miranda Lopes; Roberto Fontes Vieira; Francisco Ricardo Ferreira

    2010-01-01

    O canistel (P. campechiana) é uma fruta nativa da América Central e México, ainda pouco conhecida no Brasil. Apresenta uma polpa amarelo-alaranjada, rica em carotenoides, que tem despertado interesse como potencial de vitamina A. O objetivo deste trabalho foi determinar o teor de carotenoides e o valor provitamina A na polpa de canistel, assim como os teores de umidade e lipídeos na polpa e na semente. Os carotenoides foram separados por cromatografia em coluna aberta. O conteúdo de carotenoi...

  5. Generation of Absolute Controlled Crystal Chirality by the Removal of Crystal Water from Achiral Crystal of Nucleobase Cytosine

    OpenAIRE

    Kawasaki, Tsuneomi; Hakoda, Yuko; Mineki, Hiroko; Suzuki, Kenta; Soai, Kenso

    2010-01-01

    The enantioselective formation of chiral crystal of achiral nucleobase cytosine was achieved mediated by the crystal direction selective dehydration of crystal water in the achiral crystal of cytosine monohydrate (P21/c). Heat transfer from the enantiotopic face of the single crystal of cytosine monohydrate afforded the enantiomorphous crystal of anhydrous cytosine.

  6. Novel carotenoid cleavage dioxygenase catalyzes the first dedicated step in saffron crocin biosynthesis

    KAUST Repository

    Frusciante, Sarah

    2014-08-05

    Crocus sativus stigmas are the source of the saffron spice and accumulate the apocarotenoids crocetin, crocins, picrocrocin, and safranal, responsible for its color, taste, and aroma. Through deep transcriptome sequencing, we identified a novel dioxygenase, carotenoid cleavage dioxygenase 2 (CCD2), expressed early during stigma development and closely related to, but distinct from, the CCD1 dioxygenase family. CCD2 is the only identified member of a novel CCD clade, presents the structural features of a bona fide CCD, and is able to cleave zeaxanthin, the presumed precursor of saffron apocarotenoids, both in Escherichia coli and in maize endosperm. The cleavage products, identified through high-resolution mass spectrometry and comigration with authentic standards, are crocetin dialdehyde and crocetin, respectively. In vitro assays show that CCD2 cleaves sequentially the 7,8 and 7′,8′ double bonds adjacent to a 3-OH-β-ionone ring and that the conversion of zeaxanthin to crocetin dialdehyde proceeds via the C30 intermediate 3-OH-β-apo-8′-carotenal. In contrast, zeaxanthin cleavage dioxygenase (ZCD), an enzyme previously claimed to mediate crocetin formation, did not cleave zeaxanthin or 3-OH-β-apo-8′-carotenal in the test systems used. Sequence comparison and structure prediction suggest that ZCD is an N-truncated CCD4 form, lacking one blade of the β-propeller structure conserved in all CCDs. These results constitute strong evidence that CCD2 catalyzes the first dedicated step in crocin biosynthesis. Similar to CCD1, CCD2 has a cytoplasmic localization, suggesting that it may cleave carotenoids localized in the chromoplast outer envelope.

  7. Ozone-induced responses in Croton floribundus Spreng. (Euphorbiaceae: metabolic cross-talk between volatile organic compounds and calcium oxalate crystal formation.

    Directory of Open Access Journals (Sweden)

    Poliana Cardoso-Gustavson

    Full Text Available Here, we proposed that volatile organic compounds (VOC, specifically methyl salicylate (MeSA, mediate the formation of calcium oxalate crystals (COC in the defence against ozone (O3 oxidative damage. We performed experiments using Croton floribundus, a pioneer tree species that is tolerant to O3 and widely distributed in the Brazilian forest. This species constitutively produces COC. We exposed plants to a controlled fumigation experiment and assessed biochemical, physiological, and morphological parameters. O3 induced a significant increase in the concentrations of constitutive oxygenated compounds, MeSA and terpenoids as well as in COC number. Our analysis supported the hypothesis that ozone-induced VOC (mainly MeSA regulate ROS formation in a way that promotes the opening of calcium channels and the subsequent formation of COC in a fast and stable manner to stop the consequences of the reactive oxygen species in the tissue, indeed immobilising the excess calcium (caused by acute exposition to O3 that can be dangerous to the plant. To test this hypothesis, we performed an independent experiment spraying MeSA over C. floribundus plants and observed an increase in the number of COC, indicating that this compound has a potential to directly induce their formation. Thus, the tolerance of C. floribundus to O3 oxidative stress could be a consequence of a higher capacity for the production of VOC and COC rather than the modulation of antioxidant balance. We also present some insights into constitutive morphological features that may be related to the tolerance that this species exhibits to O3.

  8. Ozone-induced responses in Croton floribundus Spreng. (Euphorbiaceae): metabolic cross-talk between volatile organic compounds and calcium oxalate crystal formation.

    Science.gov (United States)

    Cardoso-Gustavson, Poliana; Bolsoni, Vanessa Palermo; de Oliveira, Debora Pinheiro; Guaratini, Maria Tereza Gromboni; Aidar, Marcos Pereira Marinho; Marabesi, Mauro Alexandre; Alves, Edenise Segala; de Souza, Silvia Ribeiro

    2014-01-01

    Here, we proposed that volatile organic compounds (VOC), specifically methyl salicylate (MeSA), mediate the formation of calcium oxalate crystals (COC) in the defence against ozone (O3) oxidative damage. We performed experiments using Croton floribundus, a pioneer tree species that is tolerant to O3 and widely distributed in the Brazilian forest. This species constitutively produces COC. We exposed plants to a controlled fumigation experiment and assessed biochemical, physiological, and morphological parameters. O3 induced a significant increase in the concentrations of constitutive oxygenated compounds, MeSA and terpenoids as well as in COC number. Our analysis supported the hypothesis that ozone-induced VOC (mainly MeSA) regulate ROS formation in a way that promotes the opening of calcium channels and the subsequent formation of COC in a fast and stable manner to stop the consequences of the reactive oxygen species in the tissue, indeed immobilising the excess calcium (caused by acute exposition to O3) that can be dangerous to the plant. To test this hypothesis, we performed an independent experiment spraying MeSA over C. floribundus plants and observed an increase in the number of COC, indicating that this compound has a potential to directly induce their formation. Thus, the tolerance of C. floribundus to O3 oxidative stress could be a consequence of a higher capacity for the production of VOC and COC rather than the modulation of antioxidant balance. We also present some insights into constitutive morphological features that may be related to the tolerance that this species exhibits to O3. PMID:25165889

  9. Phylogenetic and evolutionary patterns in microbial carotenoid biosynthesis are revealed by comparative genomics.

    Directory of Open Access Journals (Sweden)

    Jonathan L Klassen

    Full Text Available BACKGROUND: Carotenoids are multifunctional, taxonomically widespread and biotechnologically important pigments. Their biosynthesis serves as a model system for understanding the evolution of secondary metabolism. Microbial carotenoid diversity and evolution has hitherto been analyzed primarily from structural and biosynthetic perspectives, with the few phylogenetic analyses of microbial carotenoid biosynthetic proteins using either used limited datasets or lacking methodological rigor. Given the recent accumulation of microbial genome sequences, a reappraisal of microbial carotenoid biosynthetic diversity and evolution from the perspective of comparative genomics is warranted to validate and complement models of microbial carotenoid diversity and evolution based upon structural and biosynthetic data. METHODOLOGY/PRINCIPAL FINDINGS: Comparative genomics were used to identify and analyze in silico microbial carotenoid biosynthetic pathways. Four major phylogenetic lineages of carotenoid biosynthesis are suggested composed of: (i Proteobacteria; (ii Firmicutes; (iii Chlorobi, Cyanobacteria and photosynthetic eukaryotes; and (iv Archaea, Bacteroidetes and two separate sub-lineages of Actinobacteria. Using this phylogenetic framework, specific evolutionary mechanisms are proposed for carotenoid desaturase CrtI-family enzymes and carotenoid cyclases. Several phylogenetic lineage-specific evolutionary mechanisms are also suggested, including: (i horizontal gene transfer; (ii gene acquisition followed by differential gene loss; (iii co-evolution with other biochemical structures such as proteorhodopsins; and (iv positive selection. CONCLUSIONS/SIGNIFICANCE: Comparative genomics analyses of microbial carotenoid biosynthetic proteins indicate a much greater taxonomic diversity then that identified based on structural and biosynthetic data, and divides microbial carotenoid biosynthesis into several, well-supported phylogenetic lineages not evident

  10. Age-Related Relationships between Innate Immunity and Plasma Carotenoids in an Obligate Avian Scavenger

    Science.gov (United States)

    López-Rull, Isabel; Hornero-Méndez, Dámaso; Frías, Óscar; Blanco, Guillermo

    2015-01-01

    Variation in immunity is influenced by allocation trade-offs that are expected to change between age-classes as a result of the different environmental and physiological conditions that individuals encounter over their lifetime. One such trade-off occurs with carotenoids, which must be acquired with food and are involved in a variety of physiological functions. Nonetheless, relationships between immunity and carotenoids in species where these micronutrients are scarce due to diet are poorly studied. Among birds, vultures show the lowest concentrations of plasma carotenoids due to a diet based on carrion. Here, we investigated variations in the relationships between innate immunity (hemagglutination by natural antibodies and hemolysis by complement proteins), pathogen infection and plasma carotenoids in nestling and adult griffon vultures (Gyps fulvus) in the wild. Nestlings showed lower hemolysis, higher total carotenoid concentration and higher pathogen infection than adults. Hemolysis was negatively related to carotenoid concentration only in nestlings. A differential carotenoid allocation to immunity due to the incomplete development of the immune system of nestlings compared with adults is suggested linked to, or regardless of, potential differences in parasite infection, which requires experimental testing. We also found that individuals with more severe pathogen infections showed lower hemagglutination than those with a lower intensity infection irrespective of their age and carotenoid level. These results are consistent with the idea that intraspecific relationships between innate immunity and carotenoids may change across ontogeny, even in species lacking carotenoid-based coloration. Thus, even low concentrations of plasma carotenoids due to a scavenger diet can be essential to the development and activation of the immune system in growing birds. PMID:26544885

  11. KAROTENOID DARI MAKROALGAE DAN MIKROALGAE: POTENSI KESEHATAN APLIKASI DAN BIOTEKNOLOGI [Carotenoids from Macroalgae and Microalgae: Health Potential, Application and Biotechnology

    Directory of Open Access Journals (Sweden)

    Leenawaty Limantara3

    2012-12-01

    Full Text Available Algae, both micro and macroalgae, is one of the largest producers of carotenoids. The major composition of carotenoid on algae are β-carotene, astaxanthin, luthein, zeaxanthin, cryptoxanthin, and fucoxanthin which have important roles for human health. Carotenoids were produced by several microalgae species such as Dunaliella sallina, Haemotococcus pluvialis, Chlorella pyrenoidosa, Spirulina platensis, Nannnochloropsis oculata, and also from some macroalgae species such as Kappaphycus alvarezii, Sargassum sp, and Caulerpa sp. Carotenoids from algae has been proven as a powerful antioxidant and may prevent some degenerative diseases, cardiovascular, and cancer. Carotenoid also has been applied as a natural dye and dietary supplements. Biotechnology has been developed to increase the production of carotenoids from micro- and macroalgae. The large-scale cultivation of microalgae, either in open or closed system are shown to increase carotenoid production. During cultivation, some stress conditions can be specifically manipulated to optimize carotenoid production from microalgae.

  12. Free radical formation in crystals of 2'-deoxyguanosine 5'-monophosphate irradiated at 15 K: an ESR study

    International Nuclear Information System (INIS)

    Radiation-induced radicals in single crystals of 2'-deoxyguanosine 5'-monophosphate (5'-dGMP) at 15 K have been studied by electron spin resonance (ESR) spectroscopy. At low temperatures three radicals were analyzed in detail. The negatively charged pi anion of the guanine base completely dominated the spectra. Weaker resonances were due to an alkoxy radical with the spin density in the C3'-O3' region of the sugar moiety as well as another sugar-centered radical. The anion rapidly decayed upon exposure to uv light at 15 K or by annealing above 25 K. In both cases no successor radical was observed. The second sugar-centered radical decays at 200 K with a concomitant appearance of the resonance from the C8 H-addition radical. By annealing at 295 K the latter resonance was the only one observed. After irradiation at 295 K, however, an additional resonance from a sugar-centered radical, which has been analyzed previously by B. Rakvin and J. N. Herak (Radiat. Res. 88, 240-250 (1981)) was observed. A reinvestigation of this resonance was performed

  13. Relationship between Carotenoids, Retinol, and Estradiol Levels in Older Women

    Directory of Open Access Journals (Sweden)

    Marcello Maggio

    2015-08-01

    Full Text Available Background. In vitro evidence suggests anti-estrogenic properties for retinol and carotenoids, supporting a chemo-preventive role of these phytochemicals in estrogen-dependent cancers. During aging there are significant reductions in retinol and carotenoid concentrations, whereas estradiol levels decline during menopause and progressively increase from the age of 65. We aimed to investigate the hypothesis of a potential relationship between circulating levels of retinol, carotenoids, and estradiol (E2 in a cohort of late post-menopausal women. Methods. We examined 512 women ≥ 65 years from the InCHIANTI study. Retinol, α-caroten, β-caroten, β-criptoxantin, lutein, zeaxanthin, and lycopene levels were assayed at enrollment (1998–2000 by High-Performance Liquid Chromatography. Estradiol and testosterone (T levels were assessed by Radioimmunometry (RIA and testosterone-to-estradiol ratio (T/E2, as a proxy of aromatase activity, was also calculated. General linear models adjusted for age (Model 1 and further adjusted for other confounders including Body Mass Index (BMI BMI, smoking, intake of energy, lipids, and vitamin A; C-Reactive Protein, insulin, total cholesterol, liver function, and testosterone (Model 2 were used to investigate the relationship between retinol, carotenoids, and E2 levels. To address the independent relationship between carotenoids and E2 levels, factors significantly associated with E2 in Model 2 were also included in a fully adjusted Model 3. Results. After adjustment for age, α-carotene (β ± SE = −0.01 ± 0.004, p = 0.02 and β-carotene (β ± SE = −0.07 ± 0.02, p = 0.0007 were significantly and inversely associated with E2 levels. α-Carotene was also significantly and positively associated with T/E2 ratio (β ± SE = 0.07 ± 0.03, p = 0.01. After adjustment for other confounders (Model 2, the inverse relationship between α-carotene (β ± SE = −1.59 ± 0.61, p = 0.01, β-carotene (β ± SE = −0.29

  14. Dietary Carotenoids and Risk of Lung Cancer in a Pooled Analysis of Seven Cohort Studies

    NARCIS (Netherlands)

    Männistö, S.; Smith-Warner, S.A.; Spiegelman, D.; Albanes, D.; Anderson, K.; Brandt, P.A. van den; Cerhan, J.R.; Colditz, G.; Feskanich, D.; Freudenheim, J.L.; Giovannucci, E.; Goldbohm, R.A.; Graham, S.; Miller, A.B.; Rohan, T.E.; Virtamo, J.; Willett, W.C.; Hunter, D.J.

    2004-01-01

    Intervention trials with supplemental β-carotene have observed either no effect or a harmful effect on lung cancer risk. Because food composition databases for specific carotenoids have only become available recently, epidemiological evidence relating usual dietary levels of these carotenoids with l

  15. Critical assessment of three high performance liquid chromatography analytical methods for food carotenoid quantification

    NARCIS (Netherlands)

    Dias, M.G.; Oliveira, L.; Camoes, M.F.G.F.C.; Nunes, B.; Versloot, P.; Hulshof, P.J.M.

    2010-01-01

    Three sets of extraction/saponification/HPLC conditions for food carotenoid quantification were technically and economically compared. Samples were analysed for carotenoids a-carotene, ß-carotene, ß-cryptoxanthin, lutein, lycopene, and zeaxanthin. All methods demonstrated good performance in the ana

  16. CAROTENOID RETENTION IN MINIMALLY PROCESSED BIOFORTIFIED GREEN CORN STORED UNDER RETAIL MARKETING CONDITIONS

    Directory of Open Access Journals (Sweden)

    Natália Alves Barbosa

    2015-08-01

    Full Text Available Storing processed food products can cause alterations in their chemical compositions. Thus, the objective of this study was to evaluate carotenoid retention in the kernels of minimally processed normal and vitamin A precursor (proVA-biofortified green corn ears that were packaged in polystyrene trays covered with commercial film or in multilayered polynylon packaging material and were stored. Throughout the storage period, the carotenoids were extracted from the corn kernels using organic solvents and were quantified using HPLC. A completely factorial design including three factors (cultivar, packaging and storage period was applied for analysis. The green kernels of maize cultivars BRS1030 and BRS4104 exhibited similar carotenoid profiles, with zeaxanthin being the main carotenoid. Higher concentrations of the carotenoids lutein, β-cryptoxanthin, and β-carotene, the total carotenoids and the total vitamin A precursor carotenoids were detected in the green kernels of the biofortified BRS4104 maize. The packaging method did not affect carotenoid retention in the kernels of minimally processed green corn ears during the storage period.

  17. In vitro assessment of the bioaccessibility of carotenoids from sun-dried chilli peppers.

    Science.gov (United States)

    Pugliese, Alessandro; O'Callaghan, Yvonne; Tundis, Rosa; Galvin, Karen; Menichini, Francesco; O'Brien, Nora; Loizzo, Monica R

    2014-03-01

    Chilli peppers have been recognized as an excellent source of antioxidants as they are rich in bioactive phytochemicals such as carotenoids which are known to exert various beneficial effects in vivo. Absorption is an important factor in the determination of the potential biological effects of carotenoids. The bioaccessibility of a food constituent such as a carotenoid represents its potential to be absorbed in humans. There is very limited information in the literature regarding the content and bioaccessibility of carotenoids from dried peppers. Therefore, the objectives of the present study were: first, to determine the carotenoid content of 20 varieties of red, orange or yellow coloured sun-dried chilli peppers belonging to either of four Capsicum species (annuum, baccatum, chinense and chacoense); and second, to quantify the carotenoid micellarization (bioaccessibility) following an in vitro digestion procedure. Red peppers had a higher carotenoid content and bioaccessibility than either the orange peppers or yellow pepper. Xanthophylls showed greater bioaccessibility than carotenes. Our findings confirm that dried chilli peppers are a good source of carotenoids. PMID:24272195

  18. Excited-state properties of phenolic carotenoids from green sulphur bacteria

    Czech Academy of Sciences Publication Activity Database

    Fuciman, M.; Hříbek, P.; Chábera, P.; Pšenčík, J.; Župčanová, Anita; Vácha, František; Polívka, Tomáš

    Nové Hrady : Academic and University Center, 2008. s. 43. [ESF Workshop on Novel Methods in Exploring Carotenoid Excited State Dynamics. 21.09.2008-25.09.2008, Nové Hrady] Institutional research plan: CEZ:AV0Z50510513 Keywords : carotenoids Subject RIV: BO - Biophysics

  19. More than meets the eye: from carotenoid biosynthesis to new insights into apocarotenoid signaling

    Science.gov (United States)

    Carotenoids are a class of isoprenoid compounds synthesized almost exclusively in plants and are involved in a myriad of roles including the provision of flower and fruit pigmentation for the attraction of pollinators and seed dispersing organisms. While carotenoids are essential throughout plant de...

  20. Separation of the Carotenoid Bixin from Annatto Seeds Using Thin-Layer and Column Chromatography

    Science.gov (United States)

    McCullagh, James V.; Ramos, Nicholas

    2008-01-01

    In this experiment the carotenoid bixin is isolated from annatto ("Bixa orellana") seeds using column chromatography. The experiment has several key advantages over previous pigment separation experiments. First, unlike other experiments significant quantities of the carotenoid (typically 20 to 25 mg) can be isolated from small quantities of plant…

  1. Production and glucosylation of C50 and C 40 carotenoids by metabolically engineered Corynebacterium glutamicum.

    Science.gov (United States)

    Heider, Sabine A E; Peters-Wendisch, Petra; Netzer, Roman; Stafnes, Marit; Brautaset, Trygve; Wendisch, Volker F

    2014-02-01

    The yellow-pigmented soil bacterium Corynebacterium glutamicum ATCC13032 is accumulating the cyclic C50 carotenoid decaprenoxanthin and its glucosides. Carotenoid pathway engineering was previously shown to allow for efficient lycopene production. Here, engineering of C. glutamicum for production of endogenous decaprenoxanthin as well as of the heterologous C50 carotenoids C.p.450 and sarcinaxanthin is described. Plasmid-borne overexpression of genes for lycopene cyclization and hydroxylation from C. glutamicum, Dietzia sp., and Micrococcus luteus, in a lycopene-producing platform strain constructed here, resulted in accumulation of these three C50 carotenoids to concentrations of about 3-4 mg/g CDW. Chromosomal deletion of a putative carotenoid glycosyltransferase gene cg0730/crtX in these strains entailed production of non-glucosylated derivatives of decaprenoxanthin, C.p.450, and sarcinaxanthin, respectively. Upon introduction of glucosyltransferase genes from M. luteus, C. glutamicum, and Pantoea ananatis, these hydroxylated C50 carotenoids were glucosylated. We here also demonstrate production of the C40 carotenoids β-carotene and zeaxanthin in recombinant C. glutamicum strains and co-expression of the P. ananatis crtX gene was used to obtain glucosylated zeaxanthin. Together, our results show that C. glutamicum is a potentially valuable host for production of a wide range of glucosylated C40 and C50 carotenoids. PMID:24270893

  2. Regulatory control of high levels of carotenoid accumulation in potato tubers

    Science.gov (United States)

    Potato (Solanum tuberosum L.) tubers contain a wide range of carotenoid content. To decipher the key factors controlling carotenoid levels in tubers, four potato lines (Atlantic, Désirée, 91E22, and POR03) were examined by a combination of biochemical, molecular, and genomics approaches. These lines...

  3. Carotenoids located in human lymphocyte subpopulations and natural killer cells by Raman microspectroscopy

    NARCIS (Netherlands)

    Puppels, G.J.; Garritsen, H.S.P.; Kummer, J.A.; Greve, Jan

    1993-01-01

    The presence and subcellular location of carotenoids in human lymphocyte sub-populations (CD4+, CD8+, T-cell receptor-γδ+, and CD19+ ) and natural killer cells (CD16+ ) were studied by means of Raman microspectroscopy. In CD4+ lymphocytes a high concentration (10-3M) of carotenoids was found in the

  4. Context-dependent effects of carotenoid supplementation on reproduction in zebra finches

    NARCIS (Netherlands)

    Simons, Mirre J. P.; Briga, Michael; Leenknegt, Bas; Verhulst, Simon

    2014-01-01

    Carotenoid-dependent sexual coloration is one of the best-studied sexual signals, but how the honesty of such signals is maintained remains uncertain. The main hypotheses focus on acquisition limits and physiological use of carotenoids in immune function and regulating oxidative stress. A hypothesis

  5. Carotenoid pigments and the selectivity of psittacofulvin-based coloration systems in parrots.

    Science.gov (United States)

    McGraw, K J; Nogare, M C

    2004-07-01

    Carotenoid pigments are commonly used as colorants of feathers and bare parts by birds. However, parrots (Aves: Psittaciformes) use a novel class of plumage pigments (called psittacofulvins) that, like carotenoids, are lipid-soluble and red, orange, or yellow in color. To begin to understand how and why parrots use these pigments and not carotenoids in their feathers, we must first describe the distribution of these two types of pigments in the diet, tissues, and fluids of these birds. Here, we studied the carotenoid content of blood in five species of parrots with red in their plumage to see if they show the physiological ability to accumulate carotenoids in the body. Although Scarlet (Ara macao) and Greenwing Macaws (Ara chloroptera) and Eclectus (Eclectus roratus), African Gray (Psittacus erithacus) and Blue-fronted Amazon (Amazona aestiva) Parrots all use psittacofulvins to color their feathers red, we found that they also circulated high concentrations of both dietary (lutein, zeaxanthin, beta-cryptoxanthin) and metabolically derived (anhydrolutein, dehydrolutein) carotenoids through blood at the time of feather growth, at levels comparable to those found in many other carotenoid-colored birds. These results suggest that parrots have the potential to use carotenoids for plumage pigmentation, but preferentially avoid depositing them in feathers, which is likely under the control of the maturing feather follicle. As there is no evidence of psittacofulvins in parrot blood at the tune of feather growth, we presume that these pigments are locally synthesized by growing feathers within the follicular tissue. PMID:15253871

  6. Metabolic engineering of the carotenoid biosynthetic pathway in the yeast Xanthophyllomyces dendrorhous (Phaffia rhodozyma)

    NARCIS (Netherlands)

    Verdoes, J.C.; Sandmann, G.; Visser, H.; Diaz, M.; Mossel, van M.; Ooyen, van A.J.J.

    2003-01-01

    The crtYB locus was used as an integrative platform for the construction of specific carotenoid biosynthetic mutants in the astaxanthin-producing yeast Xanthophyllomyces dendrorhous. The crtYB gene of X. dendrorhous, encoding a chimeric carotenoid biosynthetic enzyme, could be inactivated by both si

  7. Crystal structure of α-galactosidase from Lactobacillus acidophilus NCFM: insight into tetramer formation and substrate binding.

    Science.gov (United States)

    Fredslund, Folmer; Hachem, Maher Abou; Larsen, René Jonsgaard; Sørensen, Pernille Gerd; Coutinho, Pedro M; Lo Leggio, Leila; Svensson, Birte

    2011-09-23

    Lactobacillus acidophilus NCFM is a probiotic bacterium known for its beneficial effects on human health. The importance of α-galactosidases (α-Gals) for growth of probiotic organisms on oligosaccharides of the raffinose family present in many foods is increasingly recognized. Here, the crystal structure of α-Gal from L. acidophilus NCFM (LaMel36A) of glycoside hydrolase (GH) family 36 (GH36) is determined by single-wavelength anomalous dispersion. In addition, a 1.58-Å-resolution crystallographic complex with α-d-galactose at substrate binding subsite -1 was determined. LaMel36A has a large N-terminal twisted β-sandwich domain, connected by a long α-helix to the catalytic (β/α)(8)-barrel domain, and a C-terminal β-sheet domain. Four identical monomers form a tightly packed tetramer where three monomers contribute to the structural integrity of the active site in each monomer. Structural comparison of LaMel36A with the monomeric Thermotoga maritima α-Gal (TmGal36A) reveals that O2 of α-d-galactose in LaMel36A interacts with a backbone nitrogen in a glycine-rich loop of the catalytic domain, whereas the corresponding atom in TmGal36A is from a tryptophan side chain belonging to the N-terminal domain. Thus, two distinctly different structural motifs participate in substrate recognition. The tetrameric LaMel36A furthermore has a much deeper active site than the monomeric TmGal36A, which possibly modulates substrate specificity. Sequence analysis of GH36, inspired by the observed structural differences, results in four distinct subgroups having clearly different active-site sequence motifs. This novel subdivision incorporates functional and architectural features and may aid further biochemical and structural analyses within GH36. PMID:21827767

  8. Crystal Structure of the Nonerythroid [alpha]-Spectrin Tetramerization Site Reveals Differences between Erythroid and Nonerythroid Spectrin Tetramer Formation

    Energy Technology Data Exchange (ETDEWEB)

    Mehboob, Shahila; Song, Yuanli; Witek, Marta; Long, Fei; Santarsiero, Bernard D.; Johnson, Michael E.; Fung, Leslie W.-M. (UIC)

    2010-06-21

    We have solved the crystal structure of a segment of nonerythroid {alpha}-spectrin ({alpha}II) consisting of the first 147 residues to a resolution of 2.3 {angstrom}. We find that the structure of this segment is generally similar to a corresponding segment from erythroid {alpha}-spectrin ({alpha}I) but exhibits unique differences with functional significance. Specific features include the following: (i) an irregular and frayed first helix (Helix C{prime}); (ii) a helical conformation in the junction region connecting Helix C{prime} with the first structural domain (D1); (iii) a long A1B1 loop in D1; and (iv) specific inter-helix hydrogen bonds/salt bridges that stabilize D1. Our findings suggest that the hydrogen bond networks contribute to structural domain stability, and thus rigidity, in {alpha}II, and the lack of such hydrogen bond networks in {alpha}I leads to flexibility in {alpha}I. We have previously shown the junction region connecting Helix C{prime} to D1 to be unstructured in {alpha}I (Park, S., Caffrey, M. S., Johnson, M. E., and Fung, L. W. (2003) J. Biol. Chem. 278, 21837-21844) and now find it to be helical in {alpha}II, an important difference for {alpha}-spectrin association with {beta}-spectrin in forming tetramers. Homology modeling and molecular dynamics simulation studies of the structure of the tetramerization site, a triple helical bundle of partial domain helices, show that mutations in {alpha}-spectrin will affect Helix C{prime} structural flexibility and/or the junction region conformation and may alter the equilibrium between spectrin dimers and tetramers in cells. Mutations leading to reduced levels of functional tetramers in cells may potentially lead to abnormal neuronal functions.

  9. Chronic alcohol intake up-regulates hepatic expressions of carotenoid cleavage enzymes and peroxisomal proliferator-activated receptors in rats

    Science.gov (United States)

    Excessive and chronic alcohol intake leads to a lower hepatic vitamin A status by interfering with vitamin A metabolism.Dietary provitamin A carotenoids can be converted into vitamin A mainly by carotenoid 15,15’-monooxygenase 1 (CMO1) and, to a lesser degree, carotenoid 9910’-monooxygenase 2 (CMO2)...

  10. Arabidopsis OR proteins are the major post-transcriptional regulators of phytoene synthase in mediating carotenoid biosynthesis

    Science.gov (United States)

    Carotenoids are indispensable natural pigments to plants and humans. Phytoene synthase (PSY), the rate-limiting enzyme in carotenoid biosynthetic pathway, and ORANGE (OR), a regulator of chromoplast differentiation and enhancer of carotenoid biosynthesis, represent two key proteins that control caro...

  11. Clorofilas y carotenoides: del screening a la bioactividad tisular

    OpenAIRE

    Pérez Gálvez, Antonio

    2008-01-01

    La funcionalidad de clorofilas y carotenoides surge a partir de los efectos derivados de su función, su acción y su asociación. Con estos pigmentos fotosintéticos se ha realizado un amplio screening de sus propiedades funcionales en sistemas in vitro y condiciones modelo, destacando su capacidad antioxidante y anti-mutagénica así como la inducción de eventos ligados a la diferenciación y proliferación celular. Como con la mayoría de compuestos funcionales, el establecimiento concreto de la bi...

  12. Two-Dimensional Skyrmion Lattice Formation in a Nematic Liquid Crystal Consisting of Highly Bent Banana Molecules.

    Science.gov (United States)

    Kang, Sungmin; Lee, Eun-Woo; Li, Tianqi; Liang, Xiaobin; Tokita, Masatoshi; Nakajima, Ken; Watanabe, Junji

    2016-09-12

    We synthesized a novel banana-shaped molecule based on a 1,7-naphthalene central core that exhibits a distinct mesomorphism of the nematic-to-nematic phase transition. Both the X-ray profile and direct imaging of atomic force microscopy (AFM) investigations clearly indicates the formation of an anomalous nematic phase possessing a two-dimensional (2D) tetragonal lattice with a large edge (ca. 59 Å) directed perpendicular to the director in the low-temperature nematic phase. One plausible model is proposed by an analogy of skyrmion lattice in which two types of cylinders formed from left- and right-handed twist-bend helices stack into a 2D tetragonal lattice, diminishing the inversion domain wall. PMID:27511324

  13. Carotenoid and vitamin content of Karat and other Micronesian banana cultivars.

    Science.gov (United States)

    Englberger, Lois; Schierle, Joseph; Aalbersberg, William; Hofmann, Peter; Humphries, Julia; Huang, Alvin; Lorens, Adelino; Levendusky, Amy; Daniells, Jeff; Marks, Geoffrey C; Fitzgerald, Maureen H

    2006-01-01

    We previously found high carotenoid levels in Karat and other Micronesian bananas, indicating potential importance for alleviating vitamin A deficiency and other nutritionally related health problems in the Federated States of Micronesia. Past work focused on carotenoid and mineral analyses, whereas here we investigated 16 cultivars (most not previously analysed) for a broader micronutrient profile, including seven vitamins. Karat carotenoid levels were higher than in previous analyses, confirming Karat as exceptionally carotenoid-rich. We identified an additional 10 carotenoid-rich cultivars, expanding the range having potential for alleviating vitamin A deficiency. A striking finding is the high riboflavin level in Karat, including high levels of uncharacterized flavonoids. Niacin and alpha-tocopherol are at levels that may contribute importantly to dietary intake within normal patterns of consumption. These data present a more complete basis for promoting the nutritional benefits of these banana cultivars where they are consumed in the Pacific, and potential benefits for promoting elsewhere. PMID:17135031

  14. The effect of cellular carotenoid levels in micrococcus luteus on resistance to gamma radiation

    International Nuclear Information System (INIS)

    In the present study, a biological system was developed to link the cellular carotenoid levels to Gamma radiation resistance in bacteria for the frst time. thus, in a non-photosynrhetic bacterium, in Micrococcus Luteus an inverse relationship was found between the increase in diphenylamine (DPA) concentration (5.25 μg/ml culture) and the polar cellular carotenoid pigments (C-45 and C-50 carotenoids and their glucosides). It was also found that irradiation of cells with different carotenoid concentrations with doses of γ-radiation in the range of (0.2500 gray) under oxic, air and hypoxic conditions showed that carotenoid pigments offer no significant protection as they usually do in case of visible light. (author).15 refs., 5 figs., 3 tabs

  15. New and Rare Carotenoids Isolated from Marine Bacteria and Their Antioxidant Activities

    Directory of Open Access Journals (Sweden)

    Kazutoshi Shindo

    2014-03-01

    Full Text Available Marine bacteria have not been examined as extensively as land bacteria. We screened carotenoids from orange or red pigments-producing marine bacteria belonging to rare or novel species. The new acyclic carotenoids with a C30 aglycone, diapolycopenedioc acid xylosylesters A–C and methyl 5-glucosyl-5,6-dihydro-apo-4,4′-lycopenoate, were isolated from the novel Gram-negative bacterium Rubritalea squalenifaciens, which belongs to phylum Verrucomicrobia, as well as the low-GC Gram-positive bacterium Planococcus maritimus strain iso-3 belonging to the class Bacilli, phylum Firmicutes, respectively. The rare monocyclic C40 carotenoids, (3R-saproxanthin and (3R,2′S-myxol, were isolated from novel species of Gram-negative bacteria belonging to the family Flavobacteriaceae, phylum Bacteroidetes. In this review, we report the structures and antioxidant activities of these carotenoids, and consider relationships between bacterial phyla and carotenoid structures.

  16. Genetic manipulation of carotenoid biosynthesis in the green sulfur bacterium Chlorobium tepidum

    DEFF Research Database (Denmark)

    Frigaard, Niels-Ulrik; Maresca, Julia A; Yunker, Colleen E;

    2004-01-01

    The green sulfur bacterium Chlorobium tepidum is a strict anaerobe and an obligate photoautotroph. On the basis of sequence similarity with known enzymes or sequence motifs, nine open reading frames encoding putative enzymes of carotenoid biosynthesis were identified in the genome sequence of C....... tepidum, and all nine genes were inactivated. Analysis of the carotenoid composition in the resulting mutants allowed the genes encoding the following six enzymes to be identified: phytoene synthase (crtB/CT1386), phytoene desaturase (crtP/CT0807), zeta-carotene desaturase (crtQ/CT1414), gamma......-carotene desaturase (crtU/CT0323), carotenoid 1',2'-hydratase (crtC/CT0301), and carotenoid cis-trans isomerase (crtH/CT0649). Three mutants (CT0180, CT1357, and CT1416 mutants) did not exhibit a discernible phenotype. The carotenoid biosynthetic pathway in C. tepidum is similar to that in cyanobacteria and plants...

  17. Assembly of functional photosystem complexes in Rhodobacter sphaeroides incorporating carotenoids from the spirilloxanthin pathway.

    Science.gov (United States)

    Chi, Shuang C; Mothersole, David J; Dilbeck, Preston; Niedzwiedzki, Dariusz M; Zhang, Hao; Qian, Pu; Vasilev, Cvetelin; Grayson, Katie J; Jackson, Philip J; Martin, Elizabeth C; Li, Ying; Holten, Dewey; Neil Hunter, C

    2015-02-01

    Carotenoids protect the photosynthetic apparatus against harmful radicals arising from the presence of both light and oxygen. They also act as accessory pigments for harvesting solar energy, and are required for stable assembly of many light-harvesting complexes. In the phototrophic bacterium Rhodobacter (Rba.) sphaeroides phytoene desaturase (CrtI) catalyses three sequential desaturations of the colourless carotenoid phytoene, extending the number of conjugated carbon-carbon double bonds, N, from three to nine and producing the yellow carotenoid neurosporene; subsequent modifications produce the yellow/red carotenoids spheroidene/spheroidenone (N=10/11). Genomic crtI replacements were used to swap the native three-step Rba. sphaeroides CrtI for the four-step Pantoea agglomerans enzyme, which re-routed carotenoid biosynthesis and culminated in the production of 2,2'-diketo-spirilloxanthin under semi-aerobic conditions. The new carotenoid pathway was elucidated using a combination of HPLC and mass spectrometry. Premature termination of this new pathway by inactivating crtC or crtD produced strains with lycopene or rhodopin as major carotenoids. All of the spirilloxanthin series carotenoids are accepted by the assembly pathways for LH2 and RC-LH1-PufX complexes. The efficiency of carotenoid-to-bacteriochlorophyll energy transfer for 2,2'-diketo-spirilloxanthin (15 conjugated CC bonds; N=15) in LH2 complexes is low, at 35%. High energy transfer efficiencies were obtained for neurosporene (N=9; 94%), spheroidene (N=10; 96%) and spheroidenone (N=11; 95%), whereas intermediate values were measured for lycopene (N=11; 64%), rhodopin (N=11; 62%) and spirilloxanthin (N=13; 39%). The variety and stability of these novel Rba. sphaeroides antenna complexes make them useful experimental models for investigating the energy transfer dynamics of carotenoids in bacterial photosynthesis. PMID:25449968

  18. Utilization of Microemulsions from Rhinacanthus nasutus (L.) Kurz to Improve Carotenoid Bioavailability

    Science.gov (United States)

    Ho, Nai-Hsing; Inbaraj, Baskaran Stephen; Chen, Bing-Huei

    2016-01-01

    Carotenoids have been known to reduce the risk of several diseases including cancer and cardiovascular. However, carotenoids are unstable and susceptible to degradation. Rhinacanthus nasutus (L.) Kurz (R. nasutus), a Chinese medicinal herb rich in carotenoids, was reported to possess vital biological activities such as anti-cancer. This study intends to isolate carotenoids from R. nasutus by column chromatography, identify and quantify by HPLC-MS, and prepare carotenoid microemulsions for determination of absolute bioavailability in rats. Initially, carotenoid fraction was isolated using 250 mL ethyl acetate poured into an open-column packed with magnesium oxide-diatomaceous earth (1:3, w/w). Fourteen carotenoids including internal standard β-apo-8′-carotenal were resolved within 62 min by a YMC C30 column and gradient mobile phase of methanol-acetonitrile-water (82:14:4, v/v/v) and methylene chloride. Highly stable carotenoid microemulsions were prepared using a mixture of CapryolTM90, Transcutol®HP, Tween 80 and deionized water, with the mean particle being 10.4 nm for oral administration and 10.7 nm for intravenous injection. Pharmacokinetic study revealed that the absolute bioavailability of carotenoids in microemulsions and dispersion was 0.45% and 0.11%, respectively, while a much higher value of 6.25% and 1.57% were shown for lutein, demonstrating 4-fold enhancement in bioavailability upon incorporation of R. nasutus carotenoids into a microemulsion system. PMID:27150134

  19. Crystallization from Gels

    Science.gov (United States)

    Narayana Kalkura, S.; Natarajan, Subramanian

    Among the various crystallization techniques, crystallization in gels has found wide applications in the fields of biomineralization and macromolecular crystallization in addition to crystallizing materials having nonlinear optical, ferroelectric, ferromagnetic, and other properties. Furthermore, by using this method it is possible to grow single crystals with very high perfection that are difficult to grow by other techniques. The gel method of crystallization provides an ideal technique to study crystal deposition diseases, which could lead to better understanding of their etiology. This chapter focuses on crystallization in gels of compounds that are responsible for crystal deposition diseases. The introduction is followed by a description of the various gels used, the mechanism of gelling, and the fascinating phenomenon of Liesegang ring formation, along with various gel growth techniques. The importance and scope of study on crystal deposition diseases and the need for crystal growth experiments using gel media are stressed. The various crystal deposition diseases, viz. (1) urolithiasis, (2) gout or arthritis, (3) cholelithiasis and atherosclerosis, and (4) pancreatitis and details regarding the constituents of the crystal deposits responsible for the pathological mineralization are discussed. Brief accounts of the theories of the formation of urinary stones and gallstones and the role of trace elements in urinary stone formation are also given. The crystallization in gels of (1) the urinary stone constituents, viz. calcium oxalate, calcium phosphates, uric acid, cystine, etc., (2) the constituents of the gallstones, viz. cholesterol, calcium carbonate, etc., (3) the major constituent of the pancreatic calculi, viz., calcium carbonate, and (4) cholic acid, a steroidal hormone are presented. The effect of various organic and inorganic ions, trace elements, and extracts from cereals, herbs, and fruits on the crystallization of major urinary stone and gallstone

  20. Tuning the self-assembled monolayer formation on nanoparticle surfaces with different curvatures: investigations on spherical silica particles and plane-crystal-shaped zirconia particles.

    Science.gov (United States)

    Feichtenschlager, Bernhard; Lomoschitz, Christoph J; Kickelbick, Guido

    2011-08-01

    The ordering of dodecyl-chain self-assembled monolayers (SAM) on different nanoscopic surfaces was investigated by FT-IR studies. As model systems plane-crystal-shaped ZrO(2) nanoparticles and spherical SiO(2) nanoparticles were examined. The type of capping agent was chosen dependent on the substrate, therefore dodecylphosphonic acid and octadecylphosphonic acid were used for ZrO(2) and dodecyltrimethoxysilane for SiO(2) samples. The plane ZrO(2) nanocrystals yielded more ordered alkyl-chain structures whereas spherical SiO(2) nanoparticles showed significantly lower alkyl-chain ordering. Submicron-sized silica spheres revealed a significantly higher alkyl chain ordering, comparable to an analogously prepared SAM on a non-curved plane oxidized Si-wafer. In the case of ZrO(2) nanocrystals an intense alkyl-chain alignment could be disturbed by decreasing the grafting density from the maximum of 2.1 molecules/nm(2) through the variation of coupling agent concentration to lower values. Furthermore, the co-adsorption of a different coupling agent, such as phenylphosphonic acid for ZrO(2) and phenyltrimethoxysilane for SiO(2), resulted in a significantly lower alkyl-chain ordering for ZrO(2) plane crystals and for large SiO(2) spherical particles at high grafting density. An increasing amount of order-disturbing molecules leads to a gradual decrease in alkyl-chain alignment on the surface of the inorganic nanoparticles. In the case of the ZrO(2) nanoparticle system it is shown via dynamic light scattering (DLS) that the mixed monolayer formation on the particle surface impacts the dispersion quality in organic solvents such as n-hexane. PMID:21549385