WorldWideScience

Sample records for stable extracellular tyrosinase

  1. Molecular Cloning and Characteristic Features of a Novel Extracellular Tyrosinase from Aspergillus niger PA2.

    Science.gov (United States)

    Agarwal, Pragati; Singh, Jyoti; Singh, R P

    2017-05-01

    Aspergillus niger PA2, a novel strain isolated from waste effluents of food industry, is a potential extracellular tyrosinase producer. Enzyme activity and L-DOPA production were maximum when glucose and peptone were employed as C source and nitrogen source respectively in the medium and enhanced notably when the copper was supplemented, thus depicting the significance of copper in tyrosinase activity. Tyrosinase-encoding gene from the fungus was cloned, and amplification of the tyrosinase gene yielded a 1127-bp DNA fragment and 374 amino acid residue long product that encoded for a predicted protein of 42.3 kDa with an isoelectric point of 4.8. Primary sequence analysis of A. niger PA2 tyrosinase had shown that it had approximately 99% identity with that of A. niger CBS 513.88, which was further confirmed by phylogenetic analysis. The inferred amino acid sequence of A. niger tyrosinase contained two putative copper-binding sites comprising of six histidines, a characteristic feature for type-3 copper proteins, which were highly conserved in all tyrosinases throughout the Aspergillus species. When superimposed onto the tertiary structure of A. oryzae tyrosinase, the conserved residues from both the organisms occupied same spatial positions to provide a di-copper-binding peptide groove.

  2. Purification and characterization of RNA allied extracellular tyrosinase from Aspergillus species.

    Science.gov (United States)

    Inamdar, Shrirang; Joshi, Swati; Bapat, Vishwas; Jadhav, Jyoti

    2014-02-01

    Production of L-DOPA, an anti-Parkinson's drug, using biological sources is widely studied in which tyrosinase is known to play a vital role. Tyrosinase is an omnipresent type 3 copper enzyme participating in many essential biological functions. Understanding properties of tyrosinase is essential for developing useful tyrosinase-based applications. Hence, extracellular tyrosinase from Aspergillus flavus UWFP 570 was purified using ammonium sulphate precipitation and DEAE ion exchange chromatography up to 8.3-fold. Purified protein was a riboprotein in nature containing significant amount of RNA which was confirmed colorimetrically and by electrophoresis. Removal of RNA reduced the activity and altered the conformation of tyrosinase as suggested by spectroflurometric results. Optimum pH and temperature of this 140 kDa protein were 7 and 40 °C, respectively. Copper sulphate and magnesium chloride enhanced the activity whereas in contrast FeCl₃ inhibited the activity completely. Purified tyrosinase transformed L-tyrosine (5 mM) to L-DOPA within 5 h.

  3. An immunofluorescence assay for extracellular matrix components highlights the role of epithelial cells in producing a stable, fibrillar extracellular matrix

    Directory of Open Access Journals (Sweden)

    Omar S. Qureshi

    2017-10-01

    Full Text Available Activated fibroblasts are considered major drivers of fibrotic disease progression through the production of excessive extracellular matrix (ECM in response to signals from damaged epithelial and inflammatory cells. Nevertheless, epithelial cells are capable of expressing components of the ECM, cross-linking enzymes that increase its stability and are sensitive to factors involved in the early stages of fibrosis. We therefore wanted to test the hypothesis that epithelial cells can deposit ECM in response to stimulation in a comparable manner to fibroblasts. We performed immunofluorescence analysis of components of stable, mature extracellular matrix produced by primary human renal proximal tubular epithelial cells and renal fibroblasts in response to cytokine stimulation. Whilst fibroblasts produced a higher basal level of extracellular matrix components, epithelial cells were able to deposit significant levels of fibronectin, collagen I, III and IV in response to cytokine stimulation. In response to hypoxia, epithelial cells showed an increase in collagen IV deposition but not in response to the acute stress stimuli aristolochic acid or hydrogen peroxide. When epithelial cells were in co-culture with fibroblasts we observed significant increases in the level of matrix deposition which could be reduced by transforming growth factor beta (TGF-β blockade. Our results highlight the role of epithelial cells acting as efficient producers of stable extracellular matrix which could contribute to renal tubule thickening in fibrosis.

  4. Inhibitory Effect of Arctigenin from Fructus Arctii Extract on Melanin Synthesis via Repression of Tyrosinase Expression

    Science.gov (United States)

    Park, Hwayong; Song, Kwang Hoon; Jung, Pil Mun; Kim, Ji-Eun; Kim, Mi Yoon; Ma, Jin Yeul

    2013-01-01

    To identify the active compound arctigenin in Fructus Arctii (dried seed of medicinal plant Arctium lappa) and to elucidate the inhibitory mechanism in melanogenesis, we analyzed melanin content and tyrosinase activity on B16BL6 murine melanoma and melan-A cell cultures. Water extracts of Fructus Arctii were shown to inhibit tyrosinase activity in vitro and melanin content in α-melanocyte stimulating hormone-stimulated cells to similar levels as the well-known kojic acid and arbutin, respectively. The active compound arctigenin of Fructus Arctii displayed little or no cytotoxicity at all concentrations examined and decreased the relative melanin content and tyrosinase activity in a dose-dependent manner. Melanogenic inhibitory activity was also identified in vivo with zebrafish embryo. To determine the mechanism of inhibition, the effects of arctigenin on tyrosinase gene expression and tyrosinase promoter activity were examined. Also in addition, in the signaling cascade, arctigenin dose dependently decreased the cAMP level and promoted the phosphorylation of extracellular signal-regulated kinase. This result suggests that arctigenin downregulates cAMP and the tyrosinase enzyme through its gene promoter and subsequently upregulates extracellular signal-regulated kinase activity by increasing phosphorylation in the melanogenesis signaling pathway, which leads to a lower melanin content. PMID:23781272

  5. Inhibitory Effect of Arctigenin from Fructus Arctii Extract on Melanin Synthesis via Repression of Tyrosinase Expression

    Directory of Open Access Journals (Sweden)

    Hwayong Park

    2013-01-01

    Full Text Available To identify the active compound arctigenin in Fructus Arctii (dried seed of medicinal plant Arctium lappa and to elucidate the inhibitory mechanism in melanogenesis, we analyzed melanin content and tyrosinase activity on B16BL6 murine melanoma and melan-A cell cultures. Water extracts of Fructus Arctii were shown to inhibit tyrosinase activity in vitro and melanin content in α-melanocyte stimulating hormone-stimulated cells to similar levels as the well-known kojic acid and arbutin, respectively. The active compound arctigenin of Fructus Arctii displayed little or no cytotoxicity at all concentrations examined and decreased the relative melanin content and tyrosinase activity in a dose-dependent manner. Melanogenic inhibitory activity was also identified in vivo with zebrafish embryo. To determine the mechanism of inhibition, the effects of arctigenin on tyrosinase gene expression and tyrosinase promoter activity were examined. Also in addition, in the signaling cascade, arctigenin dose dependently decreased the cAMP level and promoted the phosphorylation of extracellular signal-regulated kinase. This result suggests that arctigenin downregulates cAMP and the tyrosinase enzyme through its gene promoter and subsequently upregulates extracellular signal-regulated kinase activity by increasing phosphorylation in the melanogenesis signaling pathway, which leads to a lower melanin content.

  6. Purification and characterization of an extracellular, thermo-alkali-stable, metal tolerant laccase from Bacillus tequilensis SN4.

    Directory of Open Access Journals (Sweden)

    Sonica Sondhi

    Full Text Available A novel extracellular thermo-alkali-stable laccase from Bacillus tequilensis SN4 (SN4LAC was purified to homogeneity. The laccase was a monomeric protein of molecular weight 32 KDa. UV-visible spectrum and peptide mass fingerprinting results showed that SN4LAC is a multicopper oxidase. Laccase was active in broad range of phenolic and non-phenolic substrates. Catalytic efficiency (kcat/Km showed that 2, 6-dimethoxyphenol was most efficiently oxidized by the enzyme. The enzyme was inhibited by conventional inhibitors of laccase like sodium azide, cysteine, dithiothreitol and β-mercaptoethanol. SN4LAC was found to be highly thermostable, having temperature optimum at 85°C and could retain more than 80% activity at 70°C for 24 h. The optimum pH of activity for 2, 6-dimethoxyphenol, 2, 2'-azino bis[3-ethylbenzthiazoline-6-sulfonate], syringaldazine and guaiacol was 8.0, 5.5, 6.5 and 8.0 respectively. Enzyme was alkali-stable as it retained more than 75% activity at pH 9.0 for 24 h. Activity of the enzyme was significantly enhanced by Cu2+, Co2+, SDS and CTAB, while it was stable in the presence of halides, most of the other metal ions and surfactants. The extracellular nature and stability of SN4LAC in extreme conditions such as high temperature, pH, heavy metals, halides and detergents makes it a highly suitable candidate for biotechnological and industrial applications.

  7. Kinetics Study of Extracellular Detergent Stable Alkaline Protease from Rhizopus oryzae

    Directory of Open Access Journals (Sweden)

    Zareena Mushtaq

    2015-04-01

    Full Text Available In this study, extracellular alkaline protease was produced from Rhizopus oryzae in submerged fermentation using dairy waste (whey as a substrate. Fermentation kinetics was studied and various parameters were optimized. The strain produced maximum protease at initial medium pH of 6.0 medium depth of 26 mm, inoculum size of 2% at incubation temperature of 35ºC for 168 h of fermentation. Alkaline protease was purified to homogeneity by ammonium sulphate fractionation followed by sephadex G-100 chromatography. The molecular mass of alkaline protease was 69 kDa determined by 10% SDS-PAGE. The optimum pH and temperature of alkaline protease was 9.0 and 40ºC, respectively. Metal profile of the enzyme showed that the enzyme was non-metallic in nature. The Km , Kcat , Vmax and Kcat/Km values of purified protease were 7.0 mg/mL, 3.8 x102S-1, 54.30 µmol/min and 54.28 s-1mg -1.mL respectively, using casein as substrate. The purified alkaline protease had stability with commercial detergents.

  8. New halogenated phenylcoumarins as tyrosinase inhibitors.

    Science.gov (United States)

    Matos, Maria João; Santana, Lourdes; Uriarte, Eugenio; Delogu, Giovanna; Corda, Marcella; Fadda, Maria Benedetta; Era, Benedetta; Fais, Antonella

    2011-06-01

    With the aim to find out structural features for the tyrosinase inhibitory activity, in the present communication we report the synthesis and pharmacological evaluation of a new series of phenylcoumarin derivatives with different number of hydroxyl or ether groups and bromo substituent in the scaffold. The synthesized compounds 5-12 were evaluated as mushroom tyrosinase inhibitors showing, two of them, lower IC(50) than the umbelliferone. Compound 12 (IC(50)=215 μM) is the best tyrosinase inhibitor of this series. Copyright © 2011 Elsevier Ltd. All rights reserved.

  9. An Updated Review of Tyrosinase Inhibitors

    Directory of Open Access Journals (Sweden)

    Te-Sheng Chang

    2009-05-01

    Full Text Available Tyrosinase is a multifunctional, glycosylated, and copper-containing oxidase, which catalyzes the first two steps in mammalian melanogenesis and is responsible for enzymatic browning reactions in damaged fruits during post-harvest handling and processing. Neither hyperpigmentation in human skin nor enzymatic browning in fruits are desirable. These phenomena have encouraged researchers to seek new potent tyrosinase inhibitors for use in foods and cosmetics. This article surveys tyrosinase inhibitors newly discovered from natural and synthetic sources. The inhibitory strength is compared with that of a standard inhibitor, kojic acid, and their inhibitory mechanisms are discussed.

  10. Determination of Phytochemical Compounds, and Tyrosinase ...

    African Journals Online (AJOL)

    Purpose: To determine the phytochemical content, and tyrosinase inhibitory and antimicrobial activities of the wood ... problems from current whitening cosmetics such as ochronosis ... antibiotics may lead to drug resistance of many bacterial ...

  11. Evidence of an Unidentified Extracellular Heat-Stable Factor Produced by Lysobacter enzymogenes (OH11) that Degrade Fusarium graminearum PH1 Hyphae.

    Science.gov (United States)

    Odhiambo, Benard Omondi; Xu, Gaoge; Qian, Guoliang; Liu, Fengquan

    2017-04-01

    Lysobacter enzymogenes OH11 produces heat-stable antifungal factor (HSAF) and lytic enzymes possessing antifungal activity. This study bio-prospected for other potential antifungal factors besides those above. The cells and extracellular metabolites of L. enzymogenes OH11 and the mutants ΔchiA, ΔchiB, ΔchiC, Δclp, Δpks, and ΔpilA were examined for antifungal activity against Fusarium graminearum PH1, the causal agent of Fusarium head blight (FHB). Results evidenced that OH11 produces an unidentified extracellular heat-stable degrading metabolite (HSDM) that exhibit degrading activity on F. graminearum PH1 chitinous hyphae. Interestingly, both heat-treated and non-heat-treated extracellular metabolites of OH11 mutants exhibited hyphae-degrading activity against F. graminearum PH1. Enzyme activity detection of heat-treated metabolites ruled out the possibility of enzyme degradation activity. Remarkably, the PKS-NRPS-deficient mutant Δpks cannot produce HSAF or analogues, yet its metabolites exhibited hyphae-degrading activity. HPLC analysis confirmed no HSAF production by Δpks. Δclp lacks hyphae-degrading ability. Therefore, clp regulates HSDM and extracellular lytic enzymes production in L. enzymogenes OH11. ΔpilA had impaired surface cell motility and significantly reduced antagonistic properties. ΔchiA, ΔchiB, and ΔchiC retained hyphae-degrading ability, despite having reduced abilities to produce chitinase enzymes. Ultimately, L. enzymogenes OH11 can produce other unidentified HSDM independent of the PKS-NRPS genes. This suggests HSAF and lytic enzymes production are a fraction of the antifungal mechanisms in OH11. Characterization of HSDM, determination of its biosynthetic gene cluster and understanding its mode of action will provide new leads in the search for effective drugs for FHB management.

  12. Structure and Function of Human Tyrosinase and Tyrosinase-Related Proteins

    NARCIS (Netherlands)

    Lai, Xuelei; Wichers, Harry J.; Soler-Lopez, Montserrat; Dijkstra, Bauke W.

    2018-01-01

    Melanin is the main pigment responsible for the color of human skin, hair and eye. Its biosynthesis requires three melanogenic enzymes, tyrosinase (TYR), and the tyrosinase-related proteins TYRP1 and TYRP2. The difficulty of isolating pure and homogeneous proteins from endogenous sources has

  13. Assays for mammalian tyrosinase: a comparative study

    International Nuclear Information System (INIS)

    Jara, J.R.; Solano, F.; Lozano, J.A.

    1988-01-01

    This work describes a comparative study of the tyrosinase activity determined using three methods which are the most extensively employed; two radiometric assays using L-tyrosine as substrate (tyrosine hydroxylase and melanin formation activities) and one spectrophotometric assay using L-dopa (dopa oxidase activity). The three methods were simultaneously employed to measure the activities of the soluble, melanosomal, and microsomal tyrosinase isozymes from Harding-Passey mouse melanoma through their purification processes. The aim of this study was to find any correlation among the tyrosinase activities measured by the three different assays and to determine whether that correlation varied with the isozyme and its degree of purification. The results show that mammalian tyrosinase has a greater turnover number for L-dopa than for L-tyrosine. Thus, enzyme activity, expressed as mumol of substrate transformed per min, is higher in assays using L-dopa as substrate than those using L-tyrosine. Moreover, the percentage of hydroxylated L-tyrosine that is converted into melanin is low and is affected by several factors, apparently decreasing the tyrosinase activity measured by the melanin formation assay. Bearing these considerations in mind, average interassay factors are proposed. Their values are 10 to transform melanin formation into tyrosine hydroxylase activity, 100 to transform tyrosine hydroxylase into dopa oxidase activity, and 1,000 to transform melanin formation into dopa oxidase activity. Variations in these values due to the presence in the tyrosinase preparations of either inhibitors or regulatory factors in melanogenesis independent of tyrosinase are also discussed

  14. SEARCH OF NEW SYNTHETIC INHIBITORS OF TYROSINASE

    Directory of Open Access Journals (Sweden)

    Yu. Shesterenko

    2017-11-01

    Full Text Available Melanin pigmentation of skin plays the most important role in the protection of organism against UV-irradiation, but the excessive accumulation of melanin brings to toxic melanodermia, melasma, lentigo and other skin lesions. Tyrosinase is the key enzyme of skin melanin pigment biosynthesis. In spite of certain progress in investigation of natural and synthetic tyrosinase inhibitors, actuality of such studies is of a high level, because the existing inhibitors are in some cases unstable, expensive, toxic, requires complex methods of synthesis or isolation from natural sources. The aim of the work is screening of new tyrosinase inhibitors, using the enzyme, isolated from Agaricus bisporus. Tyrosinase was isolated from Agaricus bisporus mushrooms by a modified method. It was found, that the introduction of polyethylene glycol 4000 in the extraction process promotes 3-fold reduction of polyphenol content, which leads to increase purity of enzyme with an increase in its activity by 25%. A search for new tyrosinase inhibitors among a wide range of compounds, including derivatives of 3-chloro-1,4-naphthoquinone, isatin, 3-hydroxy-2-naphthoic acid, etc was conducted. The studied substances did not displayed inhibitory effect at concentration of 0,1-0,5 mmol/dm3.

  15. Microwave-assisted rapid extracellular synthesis of stable bio-functionalized silver nanoparticles from guava (Psidium guajava) leaf extract

    Energy Technology Data Exchange (ETDEWEB)

    Raghunandan, Deshpande [H.K.E.S' s College of Pharmacy (India); Mahesh, Bedre D. [Gulbarga University, Materials Chemistry Laboratory, Department of Material Science (India); Basavaraja, S. [Jawaharlal Nehru Centre for Advanced Scientific Research, Veeco-India Nanotechnology Laboratory (India); Balaji, S. D. [Gulbarga University, Materials Chemistry Laboratory, Department of Material Science (India); Manjunath, S. Y. [Sri Krupa, Institute of Pharmaceutical Science (India); Venkataraman, A., E-mail: raman_chem@rediffmail.com [Gulbarga University, Materials Chemistry Laboratory, Department of Material Science (India)

    2011-05-15

    Our research interest centers on microwave-assisted rapid extracellular synthesis of bio-functionalized silver nanoparticles of 26 {+-} 5 nm from guava (Psidium guajava) leaf extract with control over dimension and composition. The reaction occurs very rapidly as the formation of spherical nanoparticles almost completed within 90 s. The probable pathway of the biosynthesis is suggested. Appearance, crystalline nature, size and shape of nanoparticles are understood by UV-vis (UV-vis spectroscopy), FTIR (fourier transform infrared spectroscopy), XRD (X-ray diffraction), FESEM (field emission scanning electron microscopy) and TEM (transmission electron microscopy) techniques. Microwave-assisted route is selected for the synthesis of silver nanoparticles to carry out the reaction fast, suppress the enzymatic action and to keep the process environmentally clean and green.

  16. Microwave-assisted rapid extracellular synthesis of stable bio-functionalized silver nanoparticles from guava (Psidium guajava) leaf extract

    International Nuclear Information System (INIS)

    Raghunandan, Deshpande; Mahesh, Bedre D.; Basavaraja, S.; Balaji, S. D.; Manjunath, S. Y.; Venkataraman, A.

    2011-01-01

    Our research interest centers on microwave-assisted rapid extracellular synthesis of bio-functionalized silver nanoparticles of 26 ± 5 nm from guava (Psidium guajava) leaf extract with control over dimension and composition. The reaction occurs very rapidly as the formation of spherical nanoparticles almost completed within 90 s. The probable pathway of the biosynthesis is suggested. Appearance, crystalline nature, size and shape of nanoparticles are understood by UV–vis (UV–vis spectroscopy), FTIR (fourier transform infrared spectroscopy), XRD (X-ray diffraction), FESEM (field emission scanning electron microscopy) and TEM (transmission electron microscopy) techniques. Microwave-assisted route is selected for the synthesis of silver nanoparticles to carry out the reaction fast, suppress the enzymatic action and to keep the process environmentally clean and green.

  17. Microwave-assisted rapid extracellular synthesis of stable bio-functionalized silver nanoparticles from guava ( Psidium guajava) leaf extract

    Science.gov (United States)

    Raghunandan, Deshpande; Mahesh, Bedre D.; Basavaraja, S.; Balaji, S. D.; Manjunath, S. Y.; Venkataraman, A.

    2011-05-01

    Our research interest centers on microwave-assisted rapid extracellular synthesis of bio-functionalized silver nanoparticles of 26 ± 5 nm from guava ( Psidium guajava) leaf extract with control over dimension and composition. The reaction occurs very rapidly as the formation of spherical nanoparticles almost completed within 90 s. The probable pathway of the biosynthesis is suggested. Appearance, crystalline nature, size and shape of nanoparticles are understood by UV-vis (UV-vis spectroscopy), FTIR (fourier transform infrared spectroscopy), XRD (X-ray diffraction), FESEM (field emission scanning electron microscopy) and TEM (transmission electron microscopy) techniques. Microwave-assisted route is selected for the synthesis of silver nanoparticles to carry out the reaction fast, suppress the enzymatic action and to keep the process environmentally clean and green.

  18. Inactivation of tyrosinase photoinduced by pterin

    Energy Technology Data Exchange (ETDEWEB)

    Laura Dantola, M., E-mail: ldantola@inifta.unlp.edu.ar [Instituto de Investigaciones Fisicoquimicas Teoricas y Aplicadas (INIFTA), Departamento de Quimica, Facultad de Ciencias Exactas, Universidad Nacional de La Plata (UNLP), CCT La Plata-CONICET, Boulevard 113 y 64, 1900, La Plata (Argentina); Gojanovich, Aldana D. [Instituto de Investigaciones Fisicoquimicas Teoricas y Aplicadas (INIFTA), Departamento de Quimica, Facultad de Ciencias Exactas, Universidad Nacional de La Plata (UNLP), CCT La Plata-CONICET, Boulevard 113 y 64, 1900, La Plata (Argentina); Thomas, Andres H., E-mail: athomas@inifta.unlp.edu.ar [Instituto de Investigaciones Fisicoquimicas Teoricas y Aplicadas (INIFTA), Departamento de Quimica, Facultad de Ciencias Exactas, Universidad Nacional de La Plata (UNLP), CCT La Plata-CONICET, Boulevard 113 y 64, 1900, La Plata (Argentina)

    2012-08-03

    Highlights: Black-Right-Pointing-Pointer Under UV-A radiation, tirosinase is photoinactivated by pterin. Black-Right-Pointing-Pointer The mechanism involves an electron transfer-initiated process. Black-Right-Pointing-Pointer The photochemical process affects both activities of tyrosinase. -- Abstract: Tyrosinase catalyzes in mammals the first and rate-limiting step in the biosynthesis of the melanin, the main pigment of the skin. Pterins, heterocyclic compounds able to photoinduce oxidation of DNA and its components, accumulate in the skin of patients suffering from vitiligo, a chronic depigmentation disorder in which the protection against UV radiation fails due to the lack of melanin. Aqueous solutions of tyrosinase were exposed to UV-A irradiation (350 nm) in the presence of pterin, the parent compound of oxidized pterins, under different experimental conditions. The enzyme activity in the irradiated solutions was determined by spectrophotometry and HPLC. In this work, we present data that demonstrate unequivocally that the enzyme is photoinactivated by pterin. The mechanism of the photosensitized process involves an electron transfer from tyrosinase to the triplet excited state of pterin, formed after UV-A excitation of pterin. The biological implications of the results are discussed.

  19. Inactivation of tyrosinase photoinduced by pterin

    International Nuclear Information System (INIS)

    Laura Dántola, M.; Gojanovich, Aldana D.; Thomas, Andrés H.

    2012-01-01

    Highlights: ► Under UV-A radiation, tirosinase is photoinactivated by pterin. ► The mechanism involves an electron transfer-initiated process. ► The photochemical process affects both activities of tyrosinase. -- Abstract: Tyrosinase catalyzes in mammals the first and rate-limiting step in the biosynthesis of the melanin, the main pigment of the skin. Pterins, heterocyclic compounds able to photoinduce oxidation of DNA and its components, accumulate in the skin of patients suffering from vitiligo, a chronic depigmentation disorder in which the protection against UV radiation fails due to the lack of melanin. Aqueous solutions of tyrosinase were exposed to UV-A irradiation (350 nm) in the presence of pterin, the parent compound of oxidized pterins, under different experimental conditions. The enzyme activity in the irradiated solutions was determined by spectrophotometry and HPLC. In this work, we present data that demonstrate unequivocally that the enzyme is photoinactivated by pterin. The mechanism of the photosensitized process involves an electron transfer from tyrosinase to the triplet excited state of pterin, formed after UV-A excitation of pterin. The biological implications of the results are discussed.

  20. Screening of Peruvian Medicinal Plants for Tyrosinase Inhibitory Properties: Identification of Tyrosinase Inhibitors in Hypericum laricifolium Juss.

    Science.gov (United States)

    Quispe, Yanymee Nimesia Guillen; Hwang, Seung Hwan; Wang, Zhiqiang; Lim, Soon Sung

    2017-03-04

    Tyrosinase inhibitors are of far-ranging importance in cosmetics, medicinal products, and food industries. Peru is a diverse country with a wide variety of plants that may contain excellent anti-tyrosinase inhibitors. In the present study, the tyrosinase inhibitory properties of 50 medicinal plant extracts from Peru were investigated using tyrosinase assay. Among plant extracts, those that showed an inhibition rate >50% were Hypericum laricifolium Juss ., Taraxacum officinale F.H.Wigg ., and Muehlenbeckia vulcanica Meisn ., with H. laricifolium Juss. showing the greatest anti-tyrosinase activity. Although H. laricifolium Juss. has been widely used as a medicinal plant by Peruvians, little is known regarding its bioactive components and effects on tyrosinase activity. For this reason, we attempted to discover tyrosinase inhibitors in H. laricifolium Juss. for the first time. The bioactive components were separated by Sephadex LH-20 chromatography and eluted with 100% methanol. Eight compounds were discovered and characterized by high-performance liquid chromatography coupled with diode array detection (HPLC-DAD): protocatechuic acid, p -hydroxybenzoic acid, chlorogenic acid, vanilic acid, caffeic acid, kaempferol 3- O -glucuronide, quercetin, and kaempferol. In addition, the concentration of these compounds required for 50% inhibition (IC 50 ) of tyrosinase activity were evaluated. Quercetin exhibited the strongest tyrosinase inhibition (IC 50 14.29 ± 0.3 μM). Therefore, the Peruvian plant H. laricifolium Juss. could be a novel source for anti-tyrosinase activity.

  1. On the Metal Cofactor in the Tyrosinase Family

    Directory of Open Access Journals (Sweden)

    Francisco Solano

    2018-02-01

    Full Text Available The production of pigment in mammalian melanocytes requires the contribution of at least three melanogenic enzymes, tyrosinase and two other accessory enzymes called the tyrosinase-related proteins (Trp1 and Trp2, which regulate the type and amount of melanin. The last two proteins are paralogues to tyrosinase, and they appeared late in evolution by triplication of the tyrosinase gene. Tyrosinase is a copper-enzyme, and Trp2 is a zinc-enzyme. Trp1 has been more elusive, and the direct identification of its metal cofactor has never been achieved. However, due to its enzymatic activity and similarities with tyrosinase, it has been assumed as a copper-enzyme. Recently, recombinant human tyrosinase and Trp1 have been expressed in enough amounts to achieve for the first time their crystallization. Unexpectedly, it has been found that Trp1 contains a couple of Zn(II at the active site. This review discusses data about the metal cofactor of tyrosinase and Trps. It points out differences in the studied models, and it proposes some possible points accounting for the apparent discrepancies currently appearing. Moreover, some proposals about the possible flexibility of the tyrosinase family to uptake copper or zinc are discussed.

  2. Fermented Broth in Tyrosinase- and Melanogenesis Inhibition

    OpenAIRE

    Chin-Feng Chan; Ching-Cheng Huang; Ming-Yuan Lee; Yung-Sheng Lin

    2014-01-01

    Fermented broth has a long history of applications in the food, pharmaceutical and cosmetic industries. Recently, the use of fermented broth in skin care products is in ascendance. This review investigates the efficacy of fermented broth in inhibiting tyrosinase and melanogenesis. Possible active ingredients and hypopigmentation mechanisms of fermented broth are discussed, and potential applications of fermented broth in the cosmetic industry are also addressed.

  3. Fermented Broth in Tyrosinase- and Melanogenesis Inhibition

    Directory of Open Access Journals (Sweden)

    Chin-Feng Chan

    2014-08-01

    Full Text Available Fermented broth has a long history of applications in the food, pharmaceutical and cosmetic industries. Recently, the use of fermented broth in skin care products is in ascendance. This review investigates the efficacy of fermented broth in inhibiting tyrosinase and melanogenesis. Possible active ingredients and hypopigmentation mechanisms of fermented broth are discussed, and potential applications of fermented broth in the cosmetic industry are also addressed.

  4. Structural insight with mutational impact on tyrosinase and PKC-β interaction from Homo sapiens: Molecular modeling and docking studies for melanogenesis, albinism and increased risk for melanoma.

    Science.gov (United States)

    Banerjee, Arundhati; Ray, Sujay

    2016-10-30

    Human tyrosinase, is an important protein for biosynthetic pathway of melanin. It was studied to be phosphorylated and activated by protein kinase-C, β-subunit (PKC-β) through earlier experimentations with in vivo evidences. Documentation documents that mutation in two essentially vital serine residues in C-terminal end of tyrosinase leads to albinism. Due to the deficiency of protective shield like enzyme; melanin, albinos are at an increased peril for melanoma and other skin cancers. So, computational and residue-level insight including a mutational exploration with evolutionary importance into this mechanism lies obligatory for future pathological and therapeutic developments. Therefore, functional tertiary models of the relevant proteins were analyzed after satisfying their stereo-chemical features. Evolutionarily paramount residues for the activation of tyrosinase were perceived via multiple sequence alignment phenomena. Mutant-type tyrosinase protein (S98A and S102A) was thereby modeled, maintaining the wild-type proteins' functionality. Furthermore, this present comparative study discloses the variation in the stable residual participation (for mutant-type and wild-type tyrosinase-PKCβ complex). Mainly, an increased number of polar negatively charged residues from the wild-type tyrosinase participated with PKC-β, predominantly. Fascinatingly supported by evaluation of statistical significances, mutation even led to a destabilizing impact in tyrosinase accompanied by conformational switches with a helix-to-coil transition in the mutated protein. Even the allosteric sites in the protein got poorly hampered upon mutation leading to weaker tendency for binding partners to interact. Copyright © 2016 Elsevier B.V. All rights reserved.

  5. Tyrosinase Inhibitor Activity of Coumarin-Resveratrol Hybrids

    Directory of Open Access Journals (Sweden)

    Giovanna Delogu

    2009-07-01

    Full Text Available In the present work we report on the contribution of the coumarin moiety to tyrosinase inhibition. Coumarin-resveratrol hybrids 1-8 have been resynthesized to investigate the structure-activity relationships and the IC50 values of these compounds were measured. The results showed that these compounds exhibited tyrosinase inhibitory activity. Compound 3-(3’,4’,5’-trihydroxyphenyl-6,8-dihydroxycoumarin (8is the most potentcompound (0.27 mM, more so than umbelliferone (0.42 mM, used as reference compound. The kinetic studies revealed that compound 8 caused non-competitive tyrosinase inhibition.

  6. Tyrosinase inhibitor activity of coumarin-resveratrol hybrids.

    Science.gov (United States)

    Fais, Antonella; Corda, Marcella; Era, Benedetta; Fadda, M Benedetta; Matos, Maria Joao; Quezada, Elias; Santana, Lourdes; Picciau, Carmen; Podda, Gianni; Delogu, Giovanna

    2009-07-13

    In the present work we report on the contribution of the coumarin moiety to tyrosinase inhibition. Coumarin-resveratrol hybrids 1-8 have been resynthesized to investigate the structure-activity relationships and the IC(50) values of these compounds were measured. The results showed that these compounds exhibited tyrosinase inhibitory activity. Compound 3-(3',4',5'-trihydroxyphenyl)-6,8-dihydroxycoumarin (8)is the most potentcompound (0.27 mM), more so than umbelliferone (0.42 mM), used as reference compound. The kinetic studies revealed that compound 8 caused non-competitive tyrosinase inhibition.

  7. RFLP for TaqI at the human tyrosinase locus

    Energy Technology Data Exchange (ETDEWEB)

    Spritz, R; Strunk, K; Oetting, W; King, R

    1988-10-25

    A 1.4-kb EcoRI-PstI fragment from the mouse tyrosinase cDNA plasmid pTyrs-33 containing virtually the complete coding sequences. TaqI identifies a two-allele polymorphism with fragments of either 2.8 kb or 2.4 kb that contain most of the tyrosinase coding region. Three weak (1.4 kb, 0.9 kb, and 0.6 kb) and two very weak (5.0 and 3.2 kb) constant bands are also seen. The human tyrosinase gene has been regionally mapped to 11q14->21, and a wealy cross-hybridizing tyrosinase-related sequence mapped to 11p11.2->cen. Co-dominant segregation has been shown in two families. The RFLP was observed under normal hybridization and wash conditions.

  8. Tyrosine-like condensed derivatives as tyrosinase inhibitors.

    Science.gov (United States)

    Matos, Maria João; Santana, Lourdes; Uriarte, Eugenio; Serra, Silvia; Corda, Marcella; Fadda, Maria Benedetta; Era, Benedetta; Fais, Antonella

    2012-05-01

    We report the pharmacological evaluation of a new series of 3-aminocoumarins differently substituted with hydroxyl groups, which have been synthesized because they include in their structures the tyrosine fragment (tyrosine-like compounds), with the aim of discovering structural features necessary for tyrosinase inhibitory activity. The synthesized compounds 4 and 7-9 were evaluated in vitro as mushroom tyrosinase inhibitors. Two of the described compounds showed lower IC50 (concentration giving 50% inhibition of tyrosinase activity) than umbelliferone, used as a reference compound. Compound 7 (IC50=53µm) was the best tyrosinase inhibitor of this small series, having an IC50 value 10-fold lower than umbelliferone. Compound 7 (3-amino-7-hydroxycoumarin) had amino and hydroxyl groups precisely mimicking the same positions that both groups occupy on the tyrosine molecule. © 2012 The Authors. JPP © 2012 Royal Pharmaceutical Society.

  9. Kinetics Investigation on Mushroom Tyrosinase Inhibition of Proso Millet

    Directory of Open Access Journals (Sweden)

    Wen-Ying Huang

    2018-01-01

    Full Text Available Proso millet (Panicum miliaceum is rich in nutritive components and is widely used as a human food, feed and forage for animals, and fuel. This study investigated the effect of a proso millet extract on the inhibition of tyrosinase, a key enzyme in melanogenesis. High performance liquid chromatography analysis indicated that the proso millet extract contained phenolic tyrosinase inhibitors, such as syringic acid, p-coumaric acid, and ferulic acid. The extract had an IC50 for inhibition of tyrosinase activity of 14.02 mg/mL. A Lineweaver-Burk double reciprocal plot showed that the proso millet extract functioned as a mixed competitive and noncompetitive inhibitor. Proso millet has potential as a tyrosinase inhibitor that may have applications in the cosmetics industry.

  10. Identifying 8-hydroxynaringenin as a suicide substrate of mushroom tyrosinase.

    Science.gov (United States)

    Chang, Te-Sheng; Lin, Meng-Yi; Lin, Hsuan-Jung

    2010-01-01

    A biotransformed metabolite of naringenin was isolated from the fermentation broth of Aspergillus oryzae, fed with naringenin, and identified as 8-hydroxynaringenin based on the mass and (1)H- and (13)C-NMR spectral data. The compound showed characteristics of both an irreversible inhibitor and a substrate of mushroom tyrosinase in preincubation and HPLC analysis. These results demonstrate that 8-hydroxynaringenin belongs to a suicide substrate of mushroom tyrosinase. The partition ratio between the compound's molecules in the formation of product and in the inactivation of the enzyme was determined to be 283 +/- 21. The present study's results, together with our previous findings, which proved that both 8-hydroxydaidzein and 8-hydroxygenistein are suicide substrates of mushroom tyrosinase, show that 7,8,4'-trihydroxyl functional groups on flavonoids' skeletons play important roles in producing suicide substrate properties toward mushroom tyrosinase.

  11. Effective L-Tyrosine Hydroxylation by Native and Immobilized Tyrosinase.

    Directory of Open Access Journals (Sweden)

    Małgorzata Cieńska

    Full Text Available Hydroxylation of L-tyrosine to 3,4-dihydroxyphenylalanine (L-DOPA by immobilized tyrosinase in the presence of ascorbic acid (AH2, which reduces DOPA-quinone to L-DOPA, is characterized by low reaction yields that are mainly caused by the suicide inactivation of tyrosinase by L-DOPA and AH2. The main aim of this work was to compare processes with native and immobilized tyrosinase to identify the conditions that limit suicide inactivation and produce substrate conversions to L-DOPA of above 50% using HPLC analysis. It was shown that immobilized tyrosinase does not suffer from partitioning and diffusion effects, allowing a direct comparison of the reactions performed with both forms of the enzyme. In typical processes, additional aeration was applied and boron ions to produce the L-DOPA and AH2 complex and hydroxylamine to close the cycle of enzyme active center transformations. It was shown that the commonly used pH 9 buffer increased enzyme stability, with concomitant reduced reactivity of 76%, and that under these conditions, the maximal substrate conversion was approximately 25 (native to 30% (immobilized enzyme. To increase reaction yield, the pH of the reaction mixture was reduced to 8 and 7, producing L-DOPA yields of approximately 95% (native enzyme and 70% (immobilized. A three-fold increase in the bound enzyme load achieved 95% conversion in two successive runs, but in the third one, tyrosinase lost its activity due to strong suicide inactivation caused by L-DOPA processing. In this case, the cost of the immobilized enzyme preparation is not overcome by its reuse over time, and native tyrosinase may be more economically feasible for a single use in L-DOPA production. The practical importance of the obtained results is that highly efficient hydroxylation of monophenols by tyrosinase can be obtained by selecting the proper reaction pH and is a compromise between complexation and enzyme reactivity.

  12. Effective L-Tyrosine Hydroxylation by Native and Immobilized Tyrosinase

    Science.gov (United States)

    Lewańczuk, Marcin; Koźlecki, Tomasz; Liesiene, Jolanta; Bryjak, Jolanta

    2016-01-01

    Hydroxylation of L-tyrosine to 3,4-dihydroxyphenylalanine (L-DOPA) by immobilized tyrosinase in the presence of ascorbic acid (AH2), which reduces DOPA-quinone to L-DOPA, is characterized by low reaction yields that are mainly caused by the suicide inactivation of tyrosinase by L-DOPA and AH2. The main aim of this work was to compare processes with native and immobilized tyrosinase to identify the conditions that limit suicide inactivation and produce substrate conversions to L-DOPA of above 50% using HPLC analysis. It was shown that immobilized tyrosinase does not suffer from partitioning and diffusion effects, allowing a direct comparison of the reactions performed with both forms of the enzyme. In typical processes, additional aeration was applied and boron ions to produce the L-DOPA and AH2 complex and hydroxylamine to close the cycle of enzyme active center transformations. It was shown that the commonly used pH 9 buffer increased enzyme stability, with concomitant reduced reactivity of 76%, and that under these conditions, the maximal substrate conversion was approximately 25 (native) to 30% (immobilized enzyme). To increase reaction yield, the pH of the reaction mixture was reduced to 8 and 7, producing L-DOPA yields of approximately 95% (native enzyme) and 70% (immobilized). A three-fold increase in the bound enzyme load achieved 95% conversion in two successive runs, but in the third one, tyrosinase lost its activity due to strong suicide inactivation caused by L-DOPA processing. In this case, the cost of the immobilized enzyme preparation is not overcome by its reuse over time, and native tyrosinase may be more economically feasible for a single use in L-DOPA production. The practical importance of the obtained results is that highly efficient hydroxylation of monophenols by tyrosinase can be obtained by selecting the proper reaction pH and is a compromise between complexation and enzyme reactivity. PMID:27711193

  13. Effective L-Tyrosine Hydroxylation by Native and Immobilized Tyrosinase.

    Science.gov (United States)

    Cieńska, Małgorzata; Labus, Karolina; Lewańczuk, Marcin; Koźlecki, Tomasz; Liesiene, Jolanta; Bryjak, Jolanta

    2016-01-01

    Hydroxylation of L-tyrosine to 3,4-dihydroxyphenylalanine (L-DOPA) by immobilized tyrosinase in the presence of ascorbic acid (AH2), which reduces DOPA-quinone to L-DOPA, is characterized by low reaction yields that are mainly caused by the suicide inactivation of tyrosinase by L-DOPA and AH2. The main aim of this work was to compare processes with native and immobilized tyrosinase to identify the conditions that limit suicide inactivation and produce substrate conversions to L-DOPA of above 50% using HPLC analysis. It was shown that immobilized tyrosinase does not suffer from partitioning and diffusion effects, allowing a direct comparison of the reactions performed with both forms of the enzyme. In typical processes, additional aeration was applied and boron ions to produce the L-DOPA and AH2 complex and hydroxylamine to close the cycle of enzyme active center transformations. It was shown that the commonly used pH 9 buffer increased enzyme stability, with concomitant reduced reactivity of 76%, and that under these conditions, the maximal substrate conversion was approximately 25 (native) to 30% (immobilized enzyme). To increase reaction yield, the pH of the reaction mixture was reduced to 8 and 7, producing L-DOPA yields of approximately 95% (native enzyme) and 70% (immobilized). A three-fold increase in the bound enzyme load achieved 95% conversion in two successive runs, but in the third one, tyrosinase lost its activity due to strong suicide inactivation caused by L-DOPA processing. In this case, the cost of the immobilized enzyme preparation is not overcome by its reuse over time, and native tyrosinase may be more economically feasible for a single use in L-DOPA production. The practical importance of the obtained results is that highly efficient hydroxylation of monophenols by tyrosinase can be obtained by selecting the proper reaction pH and is a compromise between complexation and enzyme reactivity.

  14. Data in support of covalent attachment of tyrosinase onto cyanuric chloride crosslinked magnetic nanoparticles

    Directory of Open Access Journals (Sweden)

    Kourosh Abdollahi

    2016-12-01

    Full Text Available Preparation and characterization of cross linked amine-functionalized magnetic nanoparticles as an appropriate support for covalent immobilization on tyrosinase was presented in the study "Covalent immobilization of tyrosinase onto cyanuric chloride crosslinked amine-functionalized superparamagnetic nanoparticles: synthesis and characterization of the recyclable nanobiocatalyst" (Abdollahi et al., 2016 [1]. Herein, complementary data regarding X-ray powder diffraction (XRD to characterize the synthesized magnetic nanoparticles, and transmission electron microscopy (TEM to determine the size and morphology of tyrosinase immobilized magnetic nanoparticles (tyrosinase-MNPs were reported. The purification results of the extracted tyrosinase from mushroom Agaricus bisporus were provided in a purification table. The covalent immobilization of tyrosinase onto cyanuric chloride functionalized magnetic nanoparticles was proved by performing thermo-gravimetric and energy-dispersive X-ray spectroscopy analyses. The operational stability of immobilized tyrosinase was investigated by incubating tyrosinase-MNPs at different pH and temperatures.

  15. Zwitterionic sulfobetaine polymer-immobilized surface by simple tyrosinase-mediated grafting for enhanced antifouling property.

    Science.gov (United States)

    Kwon, Ho Joon; Lee, Yunki; Phuong, Le Thi; Seon, Gyeung Mi; Kim, Eunsuk; Park, Jong Chul; Yoon, Hyunjin; Park, Ki Dong

    2017-10-01

    Introducing antifouling property to biomaterial surfaces has been considered an effective method for preventing the failure of implanted devices. In order to achieve this, the immobilization of zwitterions on biomaterial surfaces has been proven to be an excellent way of improving anti-adhesive potency. In this study, poly(sulfobetaine-co-tyramine), a tyramine-conjugated sulfobetaine polymer, was synthesized and simply grafted onto the surface of polyurethane via a tyrosinase-mediated reaction. Surface characterization by water contact angle measurements, X-ray photoelectron spectroscopy and atomic force microscopy demonstrated that the zwitterionic polymer was successfully introduced onto the surface of polyurethane and remained stable for 7days. In vitro studies revealed that poly(sulfobetaine-co-tyramine)-coated surfaces dramatically reduced the adhesion of fibrinogen, platelets, fibroblasts, and S. aureus by over 90% in comparison with bare surfaces. These results proved that polyurethane surfaces grafted with poly(sulfobetaine-co-tyramine) via a tyrosinase-catalyzed reaction could be promising candidates for an implantable medical device with excellent bioinert abilities. Antifouling surface modification is one of the key strategy to prevent the thrombus formation or infection which occurs on the surface of biomaterial after transplantation. Although there are many methods to modify the surface have been reported, necessity of simple modification technique still exists to apply for practical applications. The purpose of this study is to modify the biomaterial's surface by simply immobilizing antifouling zwitterion polymer via enzyme tyrosinase-mediated reaction which could modify versatile substrates in mild aqueous condition within fast time period. After modification, pSBTA grafted surface becomes resistant to various biological factors including proteins, cells, and bacterias. This approach appears to be a promising method to impart antifouling property on

  16. Plants from Brazilian Cerrado with potent tyrosinase inhibitory activity.

    Directory of Open Access Journals (Sweden)

    Paula Monteiro Souza

    Full Text Available The increased amount of melanin leads to skin disorders such as age spots, freckles, melasma and malignant melanoma. Tyrosinase is known to be the key enzyme in melanin production. Plants and their extracts are inexpensive and rich resources of active compounds that can be utilized to inhibit tyrosinase as well as can be used for the treatment of dermatological disorders associated with melanin hyperpigmentation. Using in vitro tyrosinase inhibitory activity assay, extracts from 13 plant species from Brazilian Cerrado were evaluated. The results showed that Pouteria torta and Eugenia dysenterica extracts presented potent in vitro tyrosinase inhibition compared to positive control kojic acid. Ethanol extract of Eugenia dysenterica leaves showed significant (p<0.05 tyrosinase inhibitory activity exhibiting the IC₅₀ value of 11.88 µg/mL, compared to kojic acid (IC₅₀ value of 13.14 µg/mL. Pouteria torta aqueous extract leaves also showed significant inhibitory activity with IC₅₀ value of 30.01 µg/mL. These results indicate that Pouteria torta and Eugenia dysenterica extracts and their isolated constituents are promising agents for skin-whitening or antimelanogenesis formulations.

  17. Codon Usage Patterns of Tyrosinase Genes in Clonorchis sinensis.

    Science.gov (United States)

    Bae, Young-An

    2017-04-01

    Codon usage bias (CUB) is a unique property of genomes and has contributed to the better understanding of the molecular features and the evolution processes of particular gene. In this study, genetic indices associated with CUB, including relative synonymous codon usage and effective numbers of codons, as well as the nucleotide composition, were investigated in the Clonorchis sinensis tyrosinase genes and their platyhelminth orthologs, which play an important role in the eggshell formation. The relative synonymous codon usage patterns substantially differed among tyrosinase genes examined. In a neutrality analysis, the correlation between GC 12 and GC 3 was statistically significant, and the regression line had a relatively gradual slope (0.218). NC-plot, i.e., GC 3 vs effective number of codons (ENC), showed that most of the tyrosinase genes were below the expected curve. The codon adaptation index (CAI) values of the platyhelminth tyrosinases had a narrow distribution between 0.685/0.714 and 0.797/0.837, and were negatively correlated with their ENC. Taken together, these results suggested that CUB in the tyrosinase genes seemed to be basically governed by selection pressures rather than mutational bias, although the latter factor provided an additional force in shaping CUB of the C. sinensis and Opisthorchis viverrini genes. It was also apparent that the equilibrium point between selection pressure and mutational bias is much more inclined to selection pressure in highly expressed C. sinensis genes, than in poorly expressed genes.

  18. Purification and Characterization of Melanogenic Enzyme Tyrosinase from Button Mushroom

    Directory of Open Access Journals (Sweden)

    Kamal Uddin Zaidi

    2014-01-01

    Full Text Available Melanogenesis is a biosynthetic pathway for the formation of the pigment melanin in human skin. A key enzyme, tyrosinase, catalyzes the first and only rate-limiting steps in melanogenesis. Since the discovery of its melanogenic properties, tyrosinase has been in prime focus and microbial sources of the enzyme are sought. Agaricus bisporus widely known as the common edible mushroom, it’s taking place in high amounts of proteins, enzyme, carbohydrates, fibers, and low fat contents are frequently cited in the literature in relation to their nutritional value. In the present study tyrosinase from Agaricus bisporus was purified by ammonium sulphate precipitation, dialysis followed by gel filtration chromatography on Sephadex G-100, and ion exchange chromatography on DEAE-Cellulose; the enzyme was purified, 16.36-fold to give 26.6% yield on total activity in the crude extract and final specific activity of 52.19 U/mg. The SDS-PAGE electrophoresis showed a migrating protein band molecular weight of 95 kDa. The purified tyrosinase was optimized and the results revealed that the optimum values are pH 7.0 and temperature 35°C. The highest activity was reported towards its natural substrate, L-DOPA, with an apparent Km value of 0.933 mM. This indicated that tyrosinase purified from Agaricus bisporus is a potential source for medical applications.

  19. Inhibitory Effects of Resveratrol Analogs on Mushroom Tyrosinase Activity

    Directory of Open Access Journals (Sweden)

    Nádia Rezende Barbosa Raposo

    2012-10-01

    Full Text Available Skin pigmentation disorders typically involve an overproduction or uneven distribution of melanin, which results in skin spots. Resveratrol can inhibit tyrosinase, the active enzyme in the synthesis of melanin, but it does not inhibit the synthesis of melanin to an extent that enables its use alone as a skin whitening agent in pharmaceutical formulations, so its use as a coadjuvant in treatment of hyperpigmentation is suggested. Six resveratrol analogs were tested for tyrosinase inhibitory activity in vitro. Among the analogs tested, compound D was the most powerful tyrosinase inhibitor (IC50 = 28.66 µg/mL, two times more active than resveratrol (IC50 = 57.05 µg/mL, followed by the analogs A, E, B, F and C, respectively. This demonstrated that the hydroxylation at C4' on the phenolic ring was the molecular modification with most importance for the observed activity.

  20. Tyrosinase inhibitors from the wood of Artocarpus heterophyllus.

    Science.gov (United States)

    Nguyen, Nhan Trung; Nguyen, Mai Ha Khoa; Nguyen, Hai Xuan; Bui, Ngan Kim Nguyen; Nguyen, Mai Thanh Thi

    2012-11-26

    From the methanolic-soluble extract of the wood of Artocarpus heterophyllus, four new flavones, artocarmins A-D (1-4), and three new chalcones, artocarmitins A-C (5-7), have been isolated together with 13 known compounds. Their structures were determined on the basis of the spectroscopic data. Compounds 1-4, 6, 7, 9-16, and 20 displayed significant tyrosinase inhibitory activity. The most active compound, morachalcone A (12) (IC50, 0.013 μM), was 3000 times more active as a tyrosinase inhibitor than a positive control, kojic acid (IC50, 44.6 μM).

  1. Hydroxylation of p-substituted phenols by tyrosinase: Further insight into the mechanism of tyrosinase activity

    Energy Technology Data Exchange (ETDEWEB)

    Munoz-Munoz, Jose Luis [GENZ - Grupo de Investigacion Enzimologia, Departamento de Bioquimica y Biologia Molecular-A, Facultad de Biologia, Campus Internacional de Excelencia Campus Mare Nostrum, Universidad de Murcia, E-30100 Espinardo, Murcia (Spain); Berna, Jose [Grupo de Quimica Organica Sintetica, Departamento de Quimica Organica, Facultad de Quimica Campus Internacional de Excelencia Campus Mare Nostrum, Universidad de Murcia (Spain); Garcia-Molina, Maria del Mar; Garcia-Molina, Francisco [GENZ - Grupo de Investigacion Enzimologia, Departamento de Bioquimica y Biologia Molecular-A, Facultad de Biologia, Campus Internacional de Excelencia Campus Mare Nostrum, Universidad de Murcia, E-30100 Espinardo, Murcia (Spain); Garcia-Ruiz, Pedro Antonio [QCPAI - Grupo de Quimica de Carbohidratos, Polimeros y Aditivos Industriales, Departamento de Quimica Organica, Facultad de Quimica Campus Internacional de Excelencia Campus Mare Nostrum, Universidad de Murcia (Spain); Varon, Ramon [Departamento de Quimica-Fisica, Escuela de Ingenieros Industriales de Albacete, Universidad de Castilla la Mancha, Avda. Espana s/n. Campus Universitario, E-02071 Albacete (Spain); and others

    2012-07-27

    Highlights: Black-Right-Pointing-Pointer The action the copper complexes and tyrosinase on phenols is equivalent. Black-Right-Pointing-Pointer Isotope effect showed that nucleophilic attack to copper atom may be the slower step. Black-Right-Pointing-Pointer The value of {rho} (Hammett constant) supports an electrophilic aromatic substitution. Black-Right-Pointing-Pointer Data obtained in steady state pH 7 conditions support the mechanism of Scheme 1SM. -- Abstract: A study of the monophenolase activity of tyrosinase by measuring the steady state rate with a group of p-substituted monophenols provides the following kinetic information: k{sub cat}{sup m} and the Michaelis constant, K{sub M}{sup m}. Analysis of these data taking into account chemical shifts of the carbon atom supporting the hydroxyl group ({delta}) and {sigma}{sub p}{sup +}, enables a mechanism to be proposed for the transformation of monophenols into o-diphenols, in which the first step is a nucleophilic attack on the copper atom on the form E{sub ox} (attack of the oxygen of the hydroxyl group of C-1 on the copper atom) followed by an electrophilic attack (attack of the hydroperoxide group on the ortho position with respect to the hydroxyl group of the benzene ring, electrophilic aromatic substitution with a reaction constant {rho} of -1.75). These steps show the same dependency on the electronic effect of the substituent groups in C-4. Furthermore, a study of a solvent deuterium isotope effect on the oxidation of monophenols by tyrosinase points to an appreciable isotopic effect. In a proton inventory study with a series of p-substituted phenols, the representation of k{sub cat}{sup f{sub n}}/k{sub cat}{sup f{sub 0}} against n (atom fractions of deuterium), where k{sub cat}{sup f{sub n}} is the catalytic constant for a molar fraction of deuterium (n) and k{sub cat}{sup f{sub 0}} is the corresponding kinetic parameter in a water solution, was linear for all substrates. These results indicate that

  2. Hydroxylation of p-substituted phenols by tyrosinase: Further insight into the mechanism of tyrosinase activity

    International Nuclear Information System (INIS)

    Muñoz-Muñoz, Jose Luis; Berna, Jose; García-Molina, María del Mar; Garcia-Molina, Francisco; Garcia-Ruiz, Pedro Antonio; Varon, Ramon

    2012-01-01

    Highlights: ► The action the copper complexes and tyrosinase on phenols is equivalent. ► Isotope effect showed that nucleophilic attack to copper atom may be the slower step. ► The value of ρ (Hammett constant) supports an electrophilic aromatic substitution. ► Data obtained in steady state pH 7 conditions support the mechanism of Scheme 1SM. -- Abstract: A study of the monophenolase activity of tyrosinase by measuring the steady state rate with a group of p-substituted monophenols provides the following kinetic information: k cat m and the Michaelis constant, K M m . Analysis of these data taking into account chemical shifts of the carbon atom supporting the hydroxyl group (δ) and σ p + , enables a mechanism to be proposed for the transformation of monophenols into o-diphenols, in which the first step is a nucleophilic attack on the copper atom on the form E ox (attack of the oxygen of the hydroxyl group of C-1 on the copper atom) followed by an electrophilic attack (attack of the hydroperoxide group on the ortho position with respect to the hydroxyl group of the benzene ring, electrophilic aromatic substitution with a reaction constant ρ of −1.75). These steps show the same dependency on the electronic effect of the substituent groups in C-4. Furthermore, a study of a solvent deuterium isotope effect on the oxidation of monophenols by tyrosinase points to an appreciable isotopic effect. In a proton inventory study with a series of p-substituted phenols, the representation of k cat f n /k cat f 0 against n (atom fractions of deuterium), where k cat f n is the catalytic constant for a molar fraction of deuterium (n) and k cat f 0 is the corresponding kinetic parameter in a water solution, was linear for all substrates. These results indicate that only one of the proton transfer processes from the hydroxyl groups involved the catalytic cycle is responsible for the isotope effects. We suggest that this step is the proton transfer from the hydroxyl group

  3. Tyrosinase expression in malignant melanoma, desmoplastic melanoma, and peripheral nerve tumors

    DEFF Research Database (Denmark)

    Boyle, Jenny L; Haupt, Helen M; Stern, Jere B

    2002-01-01

    of tyrosinase expression in the differential diagnosis of melanoma, desmoplastic melanoma, and peripheral nerve sheath tumors. DESIGN: Immunoreactivity for tyrosinase, HMB-45 (anti-gp100 protein), S100 protein, CD34, and vimentin was studied in 70 tumors, including 15 melanomas (5 desmoplastic, 4 amelanotic, 6...... at 121 degrees C. RESULTS: All melanomas demonstrated positive immunostaining for tyrosinase, HMB-45, and S100 protein. Immunoreactivity for HMB-45 was generally stronger than that for tyrosinase in amelanotic lesions and significantly stronger in 1 of the desmoplastic lesions. The 4 pigmented...... neurofibromas were focally positive for tyrosinase, but did not stain for HMB-45. The pigmented schwannoma was focally positive for both tyrosinase and HMB-45. The malignant peripheral nerve sheath tumors, dermatofibrosarcoma protuberans, and dermatofibromas were nonreactive for tyrosinase and HMB-45...

  4. A Novel Photoelectrochemical Biosensor for Tyrosinase and Thrombin Detection

    Directory of Open Access Journals (Sweden)

    Jiexia Chen

    2016-01-01

    Full Text Available A novel photoelectrochemical biosensor for step-by-step assay of tyrosinase and thrombin was fabricated based on the specific interactions between the designed peptide and the target enzymes. A peptide chain with a special sequence which contains a positively charged lysine-labeled terminal, tyrosine at the other end and a cleavage site recognized by thrombin between them was designed. The designed peptide can be fixed on surface of the CdTe quantum dots (QDs-modified indium-tin oxide (ITO electrode through electrostatic attraction to construct the photoelectrochemical biosensor. The tyrosinase target can catalyze the oxidization of tyrosine by oxygen into ortho-benzoquinone residues, which results in a decrease in the sensor photocurrent. Subsequently, the cleavage site could be recognized and cut off by another thrombin target, restoring the sensor photocurrent. The decrease or increase of photocurrent in the sensor enables us to assay tyrosinase and thrombin. Thus, the detection of tyrosinase and thrombin can be achieved in the linear range from 2.6 to 32 μg/mL and from 4.5 to 100 μg/mL with detection limits of 1.5 μg/mL and 1.9 μg/mL, respectively. Most importantly, this strategy shall allow us to detect different classes of enzymes simultaneously by designing various enzyme-specific peptide substrates.

  5. Preparation of tyrosinase inhibitors and antibrowning agents using green technology.

    Science.gov (United States)

    Dong, Xue; Zhang, Yinan; He, Jia-Liang; Zhang, Shuang; Zeng, Mao-Mao; Chen, Jie; Zheng, Zong-Ping

    2016-04-15

    Chalcones and their derivatives have attracted great interests in recent years for their comprehensive biological activities. In this study, 2,4,2',4'-tetrahydroxychalcone and its two derivatives, 1,3,5-tris-(2,4-dihydroxy-phenyl)pentane-1,5-dione (new compound) and 7,2',4'-trihydroxyflavanone, were synthesized through one-pot green procedure catalyzed by boric acid in polyethylene glycol 400. Their structures were identified by ESI-MS and NMR spectral. Tyrosinase inhibitory activity and antibrowning test results showed that compounds 1-3 exhibited strong tyrosinase inhibitory activities and significant antibrowning effects on the fresh-cut lotus root slices at room temperature in 48 h. Among them, 0.01% 1,3,5-tris-(2,4-dihydroxy-phenyl)pentane-1,5-dione combined with 0.5% VC showed the best antibrowning ability. In brief, this study offers a protocol for one-pot green synthesis of high efficiency tyrosinase inhibitors which may be suitable as antibrowning agents for fresh-cut vegetables. More important, this study developed a new type of 1,5-dione derivative which may serve as new lead structures for novel tyrosinase inhibitors discovery. Copyright © 2015 Elsevier Ltd. All rights reserved.

  6. Structure and activity studies of tyrosinases and related proteins

    NARCIS (Netherlands)

    Lai, Xuelei

    2017-01-01

    The copper-containing enzyme tyrosinase catalyzes the conversion of tyrosine into DOPAquinone, which is the precursor of melanin in almost all organisms. In humans, melanin is an essential pigment that protects the skin and eyes against the UV radiation from the sun. Mutations in the genes of the

  7. A Novel Photoelectrochemical Biosensor for Tyrosinase and Thrombin Detection

    Science.gov (United States)

    Chen, Jiexia; Liu, Yifan; Zhao, Guang-Chao

    2016-01-01

    A novel photoelectrochemical biosensor for step-by-step assay of tyrosinase and thrombin was fabricated based on the specific interactions between the designed peptide and the target enzymes. A peptide chain with a special sequence which contains a positively charged lysine-labeled terminal, tyrosine at the other end and a cleavage site recognized by thrombin between them was designed. The designed peptide can be fixed on surface of the CdTe quantum dots (QDs)-modified indium-tin oxide (ITO) electrode through electrostatic attraction to construct the photoelectrochemical biosensor. The tyrosinase target can catalyze the oxidization of tyrosine by oxygen into ortho-benzoquinone residues, which results in a decrease in the sensor photocurrent. Subsequently, the cleavage site could be recognized and cut off by another thrombin target, restoring the sensor photocurrent. The decrease or increase of photocurrent in the sensor enables us to assay tyrosinase and thrombin. Thus, the detection of tyrosinase and thrombin can be achieved in the linear range from 2.6 to 32 μg/mL and from 4.5 to 100 μg/mL with detection limits of 1.5 μg/mL and 1.9 μg/mL, respectively. Most importantly, this strategy shall allow us to detect different classes of enzymes simultaneously by designing various enzyme-specific peptide substrates. PMID:26805846

  8. Tyrosinase inhibition and antioxidant properties of Asphodelus microcarpus extracts.

    Science.gov (United States)

    Di Petrillo, Amalia; González-Paramás, Ana Maria; Era, Benedetta; Medda, Rosaria; Pintus, Francesca; Santos-Buelga, Celestino; Fais, Antonella

    2016-11-09

    Asphodelus microcarpus belongs to the family Liliaceae that include several medicinal plants. In the traditional medicine plants of the genus Asphodelus are used to treat skin disorders such as ectodermal parasites, psoriasis, microbial infection and for lightening freckles. In order to find novel skin depigmenting agents, the present work was carry out to evaluate antioxidant activity and tyrosinase inhibitory potential of leaves, flowers and tubers extracts of A. microcarpus. The phytochemical composition of the active extract was also evaluated. Three different extracts (water, methanol and ethanol) from leaves, flowers and tubers of A. microcarpus were evaluated for their inhibitory effect on tyrosinase activity using L-3,4-dihydroxyphenylalanine (L-DOPA) as substrate. Inhibition of cellular tyrosinase activity and melanin production was also investigated in melanoma B16F10 cells. Antioxidant activity, total phenolic and flavonoids contents were determined using standard in vitro methods. HPLC-DAD-MS was used to identify phenolic profile of the active extract. The results showed that all extracts have a direct inhibitory anti-tyrosinase activity, with ethanolic extract from flowers (FEE) exhibiting the stronger effect. Kinetic analysis revealed that FEE acts as an uncompetitive inhibitor with a Ki value of 0.19 mg/mL. The same effect was observed in murine melanoma B16F10 cells. Cellular tyrosinase activity as well as melanin content were reduced in FEE-treated cells. The results were comparable to that of the standard tyrosinase inhibitor (kojic acid). Furthermore, the same extract showed the highest antioxidant activity and an elevated levels of total phenolics and flavonoid content. Eleven phenolic components were identified as chlorogenic acid, luteolin derivates, naringenin and apigenin. Our findings showed that FEE from A. microcarpus inhibits tyrosinase and exerted antimelanogenesis effect in B16F10 cells. This extract also showed the highest scavenging

  9. Detection of Misdistribution of Tyrosinase from Melanosomes to Lysosomes and Its Upregulation under Psoralen/Ultraviolet A with a Melanosome-Targeting Tyrosinase Fluorescent Probe.

    Science.gov (United States)

    Zhou, Jin; Shi, Wen; Li, Lihong; Gong, Qiuyu; Wu, Xiaofeng; Li, Xiaohua; Ma, Huimin

    2016-04-19

    Tyrosinase is regarded as an important biomarker of melanoma cancer, and its metabolism is closely related to some severe skin diseases such as vitiligo. Since tyrosinase is mainly located in the melanosomes of melanocytes, a probe that can specifically detect and image tysosinase in melanosomes would be in urgent demand to study the behavior of the enzyme in cells, but unfortunately, no melanosome-targeting tyrosinase fluorescent probe has been reported so far to the best of our knowledge. In this work, we have developed such a new probe, Mela-TYR, which bears morpholine as a melanosome-targeting group and 4-aminophenol as a tyrosinase reaction group. The probe exhibits not only a highly sensitive and selective off-on response to tyrosinase via oxidization cleavage, but also an accurate targeting ability toward the acidic organelles of melanosomes and lyososomes, which is validated by colocalization experiments with mCherry-tagged melanosomes as well as DND-99 (a commercial dye). The probe has been used to image the relative contents of tyrosinase in different cells. Notably, because of the tyrosinase deficiency in normal lysosomes, the probe only fluoresces in melanosomes in principle although it can accumulate in other acidic organelles like lysosomes. By virtue of this property, the misdistribution of tyrosinase from melanosomes to lysosomes in murine melanoma B16 cells under the stimulation of inulavosin is imaged in real time for the first time. Moreover, the upregulation of melanosomal tyrosinase in live B16 cells under the stimulation of psoralen/ultraviolet A is detected with our probe, and this upregulation is further verified by standard colorimetric assay. The probe provides a simple, visual method to study the metabolism of tyrosinase in cells and shows great potential in clinical diagnosis and treatments of tyrosinase-associated diseases.

  10. Phenolic tyrosinase inhibitors from the stems of Cudrania cochinchinensis.

    Science.gov (United States)

    Zheng, Zong-Ping; Zhu, Qin; Fan, Chun-Lin; Tan, Hui-Yuan; Wang, Mingfu

    2011-05-01

    The phytochemcal profiles of Cudrania cochinchinensis leaf, twig, stem and root were compared by HPLC analysis. It was found that C. cochinchinensis stem extract contained some unknown natural products with potential tyrosinase inhibitory activities. Therefore, the chemical constitutes in extract (95% ethanol) of C. cochinchinensis stem were further investigated in this study. A new racemic mixture, (±)2,3-cis-dihydromorin, and fifteen known phenolic compounds, dihydrokaempferol 7-O-β-d-qlucopyranoside, skimmin, quercetin-7-O-β-d-glucoside, 2,3-dihydroquercetin 7-O-β-d-glucoside, kaempferol-7-O-β-glucopyranoside, quercetin-3,7-di-O-β-d-glucoside, morin-7-O-β-d-glucoside, 1,3,5,8-tetrahydroxyxanthen-9-one, 2,3-trans-dihydromorin, aromadendrin, oxyresveratrol, genistin, protocatechuic acid, kaempferol 3,7-di-O-β-glucopyranoside, and naringenin were isolated. Spectral techniques (MS, (1)H NMR and (13)C NMR) were utilized for their structural identification and their inhibitory activities on mushroom tyrosinase were also evaluated. The results showed that tyrosinase inhibitory activities of (±)2,3-cis-dihydromorin (IC(50) = 31.1 μM), 2,3-trans-dihydromorin (IC(50) = 21.1 μM), and oxyresveratrol (IC(50) = 2.33 μM), were more potent than that of kojic acid (IC(50) = 50.8 μM), a well-known tyrosinase inhibitor, indicating that Cudrania cochinchinensis stem will be a great potential agent for the development of effective natural tyrosinase inhibitors.

  11. Recombinant Tyrosinase from Polyporus arcularius: Overproduction in Escherichia coli, Characterization, and Use in a Study of Aurones as Tyrosinase Effectors

    Czech Academy of Sciences Publication Activity Database

    Marková, Eva; Kotík, Michael; Křenková, Alena; Man, Petr; Haudecoeur, R.; Boumendjel, A.; Hardré, R.; Mekmouche, Y.; Dezord-Courvoisier, E.; Réglier, M.; Martínková, Ludmila

    2016-01-01

    Roč. 64, č. 14 (2016), s. 2925-2931 ISSN 0021-8561 R&D Projects: GA MŠk LD12049; GA MŠk LO1509; GA TA ČR TA04021212 Institutional support: RVO:61388971 Keywords : tyrosinase * Polyporus arcularius * Escherichia coli Subject RIV: CE - Biochemistry Impact factor: 3.154, year: 2016

  12. Identification by shape-based virtual screening and evaluation of new tyrosinase inhibitors

    Directory of Open Access Journals (Sweden)

    Qi Li

    2018-01-01

    Full Text Available Targeting tyrosinase is considered to be an effective way to control the production of melanin. Tyrosinase inhibitor is anticipated to provide new therapy to prevent skin pigmentation, melanoma and neurodegenerative diseases. Herein, we report our results in identifying new tyrosinase inhibitors. The shape-based virtual screening was performed to discover new tyrosinase inhibitors. Thirteen potential hits derived from virtual screening were tested by biological determinations. Compound 5186-0429 exhibited the most potent inhibitory activity. It dose-dependently inhibited the activity of tyrosinase, with the IC50 values 6.2 ± 2.0 µM and 10.3 ± 5.4 µM on tyrosine and L-Dopa formation, respectively. The kinetic study of 5186-0429 demonstrated that this compound acted as a competitive inhibitor. We believe the discoveries here could serve as a good starting point for further design of potent tyrosinase inhibitor.

  13. Inhibitory Effects of 5,6,7-Trihydroxyflavones on Tyrosinase

    Directory of Open Access Journals (Sweden)

    Jun Kawabata

    2007-01-01

    Full Text Available Baicalein (1, 6-hydroxyapigenin (6, 6-hydroxygalangin (13 and 6-hydroxy-kaempferol (14, which are naturally occurring flavonoids from a set of 14 hydroxy-flavones tested, exhibited high inhibitory effects on tyrosinase with respect to L-DOPA,while each of the 5,6,7-trihydroxyflavones 1, 6, 13 or 14 acted as a cofactor tomonophenolase. Moreover, 6-hydroxykaempferol (14 showed the highest activity andwas a competitive inhibitor of tyrosinase compared to L-DOPA. 5,6,7-Trihydroxyflavones 1, 6, 13 or 14 showed also high antioxidant activities. Hence, weconclude that the 5,6,7-trihydroxy-flavones are useful as good depigmentation agentswith inhibitory effects in addition to their antioxidant properties.

  14. Tyrosinase inhibitory components from Aloe vera and their antiviral activity.

    Science.gov (United States)

    Kim, Jang Hoon; Yoon, Ju-Yeon; Yang, Seo Young; Choi, Seung-Kook; Kwon, Sun Jung; Cho, In Sook; Jeong, Min Hee; Ho Kim, Young; Choi, Gug Seoun

    2017-12-01

    A new compound, 9-dihydroxyl-2'-O-(Z)-cinnamoyl-7-methoxy-aloesin (1), and eight known compounds (2-9) were isolated from Aloe vera. Their structures were elucidated using 1D/2D nuclear magnetic resonance and mass spectra. Compound 9 exhibited reversible competitive inhibitory activity against the enzyme tyrosinase, with an IC 50 value of 9.8 ± 0.9 µM. A molecular simulation revealed that compound 9 interacts via hydrogen bonding with residues His244, Thr261, and Val283 of tyrosinase. Additionally, compounds 3 and 7 were shown by half-leaf assays to exhibit inhibitory activity towards Pepper mild mottle virus.

  15. Screening Marker Components Of Tyrosinase Inhibitor From Xylocarpus Granatum Stem

    Directory of Open Access Journals (Sweden)

    Latifah K Darusman

    2017-03-01

    Full Text Available The aim of our research was to screen the marker components of tyrosinase inhibitor from Xylocarpus granatum stem collected from Pulau Sebuku, South Kalimantan, Indonesia.  The screening method started from selection of part of X. granatum, stem or stem bark.  Stem and stem bark of X. granatum were dried and grounded before submitted to methanol.  The stem extracts is more potent as tyrosinase inhibitor (IC50 for monophenolase is 45.12 μg/ml and diphenolase is 31.59μg/ml compared to the bark extracts. The IC50 values of kojic acid as positive control are 17.43μg/ml for monophenolase and 20.69 μg/ml for diphenolase. The stem extract then separated with silica gel column chromatography and preparative thin layer chromatography.  The results showed that component with Rf 0,25 and 0.63 (TLC analysis with stationary phase silica gel GF254 and mobile phase ethyl acetic: methanol (8:2 are the marker components as tyrosinase inhibitor for X. granatum.

  16. Association of Tyrosinase (TYR and Tyrosinase-related Protein 1 (TYRP1 with Melanic Plumage Color in Korean Quails (

    Directory of Open Access Journals (Sweden)

    Ying Xu

    2013-11-01

    Full Text Available TYR (Tyrosinase and TYRP1 (Tyrosinase-related protein 1 play crucial roles in determining the coat color of birds. In this paper, we aimed to characterize the relationship of TYR and TYRP1 genes with plumage colors in Korean quails. The SNPs were searched by cDNA sequencing and PCR-SSCP in three plumage color Korean quails (maroon, white and black plumage. Two SNPs (367T→C and 1153C→T were found in the coding region of TYRP1 gene, but had no significant association with plumage phenotype in Korean quails. The expression of TYR was higher in black plumage quails than that in maroon plumage quails. In contrast, the expression of TYRP1 was lower in black plumage quails than that in maroon plumage quails. This study suggested that the melanic plumage color in Korean quails may be associated with either increased production of TYR or decreased production of TYRP1.

  17. Investigation of the mechanisms by which UV irradiation activates the tyrosinase gene

    International Nuclear Information System (INIS)

    Bao, Y.

    2000-04-01

    Tyrosinase, tyrosinase related protein-1 (TRP-1) and tyrosinase related protein-2 (TRP-2) are the enzymes involved in melanin pigment synthesis. They are expressed specifically in melanocytic cells. UV irradiation is the major physiological stimulant of melanogenesis. Tyrosinase is the rate-limiting enzyme in melanin synthesis and its activity is regulated by UV irradiation in melanocytes. The molecular mechanism underlying the activation of tyrosinase by UV is still not clear. In this thesis, the effects of UV irradiation on tyrosinase, TRP-1 and TRP-2 gene expression in mouse B16 melanoma cells were studied as well as the effects of UV irradiation on the activity of the tyrosinase promoter in mouse, and human melanoma cells. UV irradiation caused an increase in tyrosinase mRNA level, without change in either TRP-1 or TRP-2 mRNA levels, as determined by Northern blot analysis. In order to determine whether UV- induced increase of tyrosinase mRNA expression involved modulation of tyrosinase promoter activity, transient transfection approaches involving a series of constructs containing either chloramphenicol acetyl transferase (CAT) or luciferase reporter genes linked to different lengths of the tyrosinase gene- promoter were used. UV irradiation specifically induced CAT gene expression from both the mouse and the human tyrosinase promoters, suggesting that UV irradiation induced the transcription of the tyrosinase gene. These observations indicated that the promoter region between -250 and -150 bp of the human tyrosinase promoter may contain important cis-regulatory elements involved in the UV response. To localise the cis-regulatory elements responsible for the UV response of the tyrosinase promoter, the 100-bp between -250 bp and -150 bp of the tyrosinase promoter was inserted upstream of a CAT reporter. It was shown that transcription from the 100-bp promoter fragment was activated by UV irradiation. Mutations of a potential cAMP response element (CRE) motif

  18. Structure of Human Tyrosinase Related Protein 1 Reveals a Binuclear Zinc Active Site Important for Melanogenesis

    NARCIS (Netherlands)

    Lai, Xuelei; Wichers, Harry J.; Soler-Lopez, Montserrat; Dijkstra, Bauke W.

    2017-01-01

    Tyrosinase-related protein 1 (TYRP1) is one of three tyrosinase-like glycoenzymes in human melanocytes that are key to the production of melanin, the compound responsible for the pigmentation of skin, eye, and hair. Difficulties with producing these enzymes in pure form have hampered the

  19. Crystal Structure of Agaricus bisporus Mushroom Tyrosinase : Identity of the Tetramer Subunits and Interaction with Tropolone

    NARCIS (Netherlands)

    Ismaya, Wangsa T.; Rozeboom, Henriette J.; Weijn, Amrah; Mes, Jurriaan J.; Fusetti, Fabrizia; Wichers, Harry J.; Dijkstra, Bauke W.

    2011-01-01

    Tyrosinase catalyzes the conversion of phenolic compounds into their quinone derivatives, which are precursors for the formation of melanin, a ubiquitous pigment in living organisms. Because of its importance for browning reactions in the food industry, the tyrosinase from the mushroom Agaricus

  20. Crystal Structure of Agaricus bisporus Mushroom Tyrosinase: Identity of the Tetramer Subunits and Interaction with Tropolone

    NARCIS (Netherlands)

    Ismaya, W.T.; Rozeboom, H.J.; Weijn, A.; Mes, J.J.; Fusetti, F.; Wichers, H.J.; Dijkstra, B.W.

    2011-01-01

    Tyrosinase catalyzes the conversion of phenolic compounds into their quinone derivatives, which are precursors for the formation of melanin, a ubiquitous pigment in living organisms. Because of its importance for browning reactions in the food industry, the tyrosinase from the mushroom Agaricus

  1. Extracellular Gd-CA

    DEFF Research Database (Denmark)

    Thomsen, Henrik S; Marckmann, Peter

    2008-01-01

    Until recently it was believed that extracellular gadolinium-based contrast agents were safe for both the kidneys and all other organs within the dose range up to 0.3 mmol/kg body weight. However, in 2006, it was demonstrated that some gadolinium-based contrast agents may trig the development...... gadolinium-based agent (3-7% versus 0-1% per injection) in patients with reduced renal function. Prevalence after exposure to two gadodiamide injections is as high as 36% in patients with chronic kidney disease (CKD) stage 5. No report of NSF after the most stable agents has been reported in the peer...

  2. Melanoma cells present high levels of HLA-A2-tyrosinase in association with instability and aberrant intracellular processing of tyrosinase.

    Science.gov (United States)

    Michaeli, Yael; Sinik, Keren; Haus-Cohen, Maya; Reiter, Yoram

    2012-04-01

    Short-lived protein translation products are proposed to be a major source of substrates for major histocompatibility complex (MHC) class I antigen processing and presentation; however, a direct link between protein stability and the presentation level of MHC class I-peptide complexes has not been made. We have recently discovered that the peptide Tyr((369-377)) , derived from the tyrosinase protein is highly presented by HLA-A2 on the surface of melanoma cells. To examine the molecular mechanisms responsible for this presentation, we compared characteristics of tyrosinase in melanoma cells lines that present high or low levels of HLA-A2-Tyr((369-377)) complexes. We found no correlation between mRNA levels and the levels of HLA-A2-Tyr((369-377)) presentation. Co-localization experiments revealed that, in cell lines presenting low levels of HLA-A2-Tyr((369-377)) complexes, tyrosinase co-localizes with LAMP-1, a melanosome marker, whereas in cell lines presenting high HLA-A2-Tyr((369-377)) levels, tyrosinase localizes to the endoplasmic reticulum. We also observed differences in tyrosinase molecular weight and glycosylation composition as well as major differences in protein stability (t(1/2) ). By stabilizing the tyrosinase protein, we observed a dramatic decrease in HLA-A2-tyrosinase presentation. Our findings suggest that aberrant processing and instability of tyrosinase are responsible for the high presentation of HLA-A2-Tyr((369-377)) complexes and thus shed new light on the relationship between intracellular processing, stability of proteins, and MHC-restricted peptide presentation. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Inhibitory Effect of the Ethyl Acetate Fraction of Ethanol Extract from Rhus verniciflua Stokes Wood on the Activity of Mushroom Tyrosinase

    Directory of Open Access Journals (Sweden)

    Hong Xia Chen

    2014-10-01

    Full Text Available Solvent extracts of Rhus verniciflua Stokes wood were made using decompressing inner ebullition, and a Box-Behnken design was used to optimize extraction conditions to produce an extract that inhibited tyrosinase activity. The chemical compositions and inhibition rates were determined in extracts made with petroleum ether, ethyl acetate, n-butanol, and an aqueous fractionation. The ethyl acetate fraction had the highest total phenolic content and inhibition rates. The main flavonoids in this fraction were 0.531% fisetin, 7.582% fustin, 0.848% sulfuretin, and 0.272% butein. The effects of the extract on the monophenolase and diphenolase activity of mushroom tyrosinase were studied using the Lineweaver-Burk equation to determine the effect of the extract on inhibition of tyrosinase activity. The results showed that the extract inhibited both the monophenolase and diphenolase activity of the enzyme. The IC50 of the ethyl acetate extract was 308 μg/mL, with the lag period of the enzyme being obviously lengthened; it was estimated to be 2.45 min in the absence of the inhibitor and extended to 9.63 min in the presence of 500 μg/mL of extract. The ethyl acetate extract acted as a mixed type inhibitor. The KI was less than the KIS, which demonstrates that the [ESI] is less stable than [EI], suggesting that the extract could easily combine with free enzyme in the enzyme catalysis system, thus affecting enzyme catalysis on the substrate.

  4. Aspergillus niger PA2: a novel strain for extracellular biotransformation of L-tyrosine into L-DOPA.

    Science.gov (United States)

    Agarwal, Pragati; Pareek, Nidhi; Dubey, Swati; Singh, Jyoti; Singh, R P

    2016-05-01

    L-DOPA (3,4-dihydroxyphenyl-L-alanine), an amino acid derivative is the most widely used drug of choice for the treatment of Parkinson's disease and other neurologic injuries. The present study deals with the elevated biochemical transformation of L-tyrosine to L-DOPA by Aspergillus niger PA2, a potent tyrosinase producer, isolated from decomposed food wastes. This appears to be the first report on A. niger as a notable extracellular tyrosinase producer. The extracellular tyrosinase activity produced remarkably higher levels of L-DOPA, i.e. 2.44 mg mL(-1) when the media was supplemented with 5 mg mL(-1) L-tyrosine. The optimum pH for tyrosinase production was 6.0, with the maximal L-DOPA production at the same pH. The product thus produced was analyzed by thin-layer chromatography, UV spectroscopy, high-performance liquid chromatography and Fourier transform infrared spectroscopy, that had denoted this to be L-DOPA. Kinetic parameters viz. Y p/s, Q s and Q p had further indicated the notable levels of production. Thus, Aspergillus niger PA2 could be a promising resource and may be further exploited for large-scale production of L-DOPA.

  5. Inhibitory effect of burdock leaves on elastase and tyrosinase activity

    Science.gov (United States)

    Horng, Chi-Ting; Wu, Hsing-Chen; Chiang, Ni-Na; Lee, Chiu-Fang; Huang, Yu-Syuan; Wang, Hui-Yun; Yang, Jai-Sing; Chen, Fu-An

    2017-01-01

    Burdock (Arctium lappa L.) leaves generate a considerable amount of waste following burdock root harvest in Taiwan. To increase the use of burdock leaves, the present study investigated the optimal methods for producing burdock leaf extract (BLE) with high antioxidant polyphenolic content, including drying methods and solvent extraction concentration. In addition, the elastase and tyrosinase inhibitory activity of BLE was examined. Burdock leaves were dried by four methods: Shadow drying, oven drying, sun drying and freeze-drying. The extract solution was then subjected to total polyphenol content analysis and the method that produced BLE with the highest amount of total antioxidant components was taken forward for further analysis. The 1,1-diphenyl-2-pycrylhydrazyl scavenging, antielastase and antityrosinase activity of the BLE were measured to enable the evaluation of the antioxidant and skin aging-associated enzyme inhibitory activities of BLE. The results indicated that the total polyphenolic content following extraction with ethanol (EtOH) was highest using the freeze-drying method, followed by the oven drying, shadow drying and sun drying methods. BLE yielded a higher polyphenol content and stronger antioxidant activity as the ratio of the aqueous content of the extraction solvent used increased. BLE possesses marked tyrosinase and elastase inhibitory activities, with its antielastase activity notably stronger compared with its antityrosinase activity. These results indicate that the concentration of the extraction solvent was associated with the antioxidant and skin aging-associated enzyme inhibitory activity of BLE. The reactive oxygen species scavenging theory of skin aging may explain the tyrosinase and elastase inhibitory activity of BLE. In conclusion, the optimal method for obtaining BLE with a high antioxidant polyphenolic content was freeze-drying followed by 30–50% EtOH extraction. In addition, the antielastase and antityrosinase activities of the

  6. Antioxidant Activity of Some Plant Extracts Towards Xanthine Oxidase, Lipoxygenase and Tyrosinase

    Directory of Open Access Journals (Sweden)

    Pi-Yu Chen

    2009-08-01

    Full Text Available Natural products have the potential to be developed into new drugs for the treatment of various diseases. The aim of the present study was to screen the antioxidant activities of some common edible fruits, garden plants and medicinal plants indigenous to Taiwan. This was performed by assessing the activities of lipoxygenase, xanthine oxidase and tyrosinase following incubation with extracts from these plants. A further aim was to use HPLC-DAD and tyrosinase to chromatographically identify the antioxidative constituents obtained from an extract exhibiting strong antioxidative properties. The acetone extracts of 27 cultivated plant species from Taiwan were tested for antioxidant activities towards xanthine oxidase, tyrosinase and lipoxygenase using spectrophotometric assays. Koelreuteria henryi, Prunus campanulata, and Rhodiola rosea showed the highest xanthine oxidase inhibitory activities. Camellia sinensis, Rhodiola rosea, and Koelreuteria henryi exhibited good tyrosinase inhibitory activities and potent anti-lipoxygenase activities. As Koelreuteria henryi had notable significant inhibitory activities towards xanthine oxidase, tyrosinase, and lipoxygenase, it was further tested with tyrosinase and HPLC-DAD. The results from this part of the study revealed that the more powerful the antioxidant capability of the extracted component, the greater the decrease in peak height obtained after reacting with tyrosinase. Additional studies are warranted to further characterize the compounds responsible for the antioxidant properties of the examined extracts.

  7. DMEM enhances tyrosinase activity in B16 mouse melanoma cells and human melanocytes

    Directory of Open Access Journals (Sweden)

    Panpen Diawpanich

    2008-07-01

    Full Text Available Media components may affect the activities of cultured cells. In this study, tyrosinase activity was evaluated by using B16-F10 mouse melanoma cell lines (B16-F10 and primary human melanocytes cultured in different media. An optical density measurement and a L-dopa reaction assay were used as the determination of the tyrosinase activity. The study of B16-F10 found the optical density to be 2010, 2246 and 2961 in cells cultured in RPMI Medium 1640 (RPMI1640,Minimum Essential Medium (MEM and Dulbecco’s Modified Eagle Medium (DMEM, respectively. Moreover, compared to RPMI 1640 and MEM, DMEM showed the darkest color of melanin formation in culture media and in cells after the L-dopa reaction assay. Addition of kojic acid showed a significant inhibitory effect on tyrosinase activity in all media.Whereas MCDB153 showed no significant effect on human melanocytes, DMEM caused a dramatic increase in tyrosinase activity after 4 days of cultivation. Addition of kojic acid showed a significant tyrosinase inhibitory effect in DMEM only. Furthermore, an active ingredient in green tea, epigallocathechin gallate (EGCG could inhibit tyrosinase activity in both B16-F10 and human melanocytes cultured in DMEM. In summary, these results suggest that DMEM is a suitable medium that provides high detection sensitivity in a tyrosinase inhibition assay.

  8. Toxin detection using a tyrosinase-coupled oxygen electrode.

    Science.gov (United States)

    Smit, M H; Rechnitz, G A

    1993-02-15

    An enzyme-based "electrochemical canary" is described for the detection of cyanide. The sensing system imitates cyanide's site of toxicity in the mitochondria. The terminal sequence of electron transfer in aerobic respiration is mimicked by mediator coupling of tyrosinase catalysis to an electro-chemical system. An enzyme-coupled oxygen electrode is created which is sensitive to selective poisoning. Biocatalytic reduction of oxygen is promoted by electrochemically supplying tyrosinase with electrons. Thus, ferrocyanide is generated at a cathode and mediates the enzymatic reduction of oxygen to water. An enzyme-dependent reductive current can be monitored which is inhibited by cyanide in a concentration-dependent manner. Oxygen depletion in the reaction layer can be minimized by addressing enzyme activity using a potential pulsing routine. Enzyme activity is electrochemically initiated and terminated and the sensor becomes capable of continuous monitoring. Cyanide poisoning of the biological component is reversible, and it can be reused after rinsing. The resulting sensor detects cyanide based on its biological activity rather than its physical or chemical properties.

  9. Tyrosinase-Based Biosensors for Selective Dopamine Detection

    Directory of Open Access Journals (Sweden)

    Monica Florescu

    2017-06-01

    Full Text Available A novel tyrosinase-based biosensor was developed for the detection of dopamine (DA. For increased selectivity, gold electrodes were previously modified with cobalt (II-porphyrin (CoP film with electrocatalytic activity, to act both as an electrochemical mediator and an enzyme support, upon which the enzyme tyrosinase (Tyr was cross-linked. Differential pulse voltammetry was used for electrochemical detection and the reduction current of dopamine-quinone was measured as a function of dopamine concentration. Our experiments demonstrated that the presence of CoP improves the selectivity of the electrode towards dopamine in the presence of ascorbic acid (AA, with a linear trend of concentration dependence in the range of 2–30 µM. By optimizing the conditioning parameters, a separation of 130 mV between the peak potentials for ascorbic acid AA and DA was obtained, allowing the selective detection of DA. The biosensor had a sensitivity of 1.22 ± 0.02 µA·cm−2·µM−1 and a detection limit of 0.43 µM. Biosensor performances were tested in the presence of dopamine medication, with satisfactory results in terms of recovery (96%, and relative standard deviation values below 5%. These results confirmed the applicability of the biosensors in real samples such as human urine and blood serum.

  10. The relationship between Na+/H+ exchanger expression and tyrosinase activity in human melanocytes

    International Nuclear Information System (INIS)

    Smith, Dustin R.; Spaulding, Deborah T.; Glenn, Hayden M.; Fuller, Bryan B.

    2004-01-01

    The activity of melanosome-associated tyrosinase in human melanocytes differs based on racial skin type. In melanocytes from Black skin, tyrosinase activity is high while in White melanocytes the activity of the enzyme is low. Recent studies suggest that low tyrosinase activity in White melanocytes may be due to an acidic pH environment within the melanosome. Because sodium/hydrogen (Na + /H + ) exchangers (NHEs) are known to regulate intracellular pH, melanocytes were treated with NHE inhibitors to determine what effect this inhibition might have on tyrosinase activity. Treatment of Black melanocytes with ethyl-isopropyl amiloride (EIPA) caused a rapid dose-dependent inhibition of tyrosinase activity. This inhibition was not due to either direct enzyme inhibition or to a decrease in tyrosinase abundance. In contrast, treatment of White melanocytes with EIPA, cimetidine, or clonidine resulted in little inhibition of tyrosinase activity. Reverse transcriptase-polymerase chain reaction (RT-PCR) and Western blot analysis showed that both Black and White melanocytes expressed mRNA and protein for NHE-1, NHE-3, NHE-5, NHE-6, and NHE-7. Immunohistochemical analysis showed that NHE-7 and NHE-3 co-localized with the melanosomal protein, Tyrosinase Related Protein-1 (TRP-1). In addition, the vesicular proton pump, vesicular ATPase (V-ATPase), was found to be present in both White and Black melanosomes, indicating that organelles from both racial skin types are capable of being acidified. The results suggest that one or more NHEs may help regulate melanosome pH and tyrosinase activity in human melanocytes

  11. SCREEN-PRINTED TYROSINASE-CONTAINING ELECTRODES FOR THE BIOSENSING OF ENZYME INHIBITORS

    Science.gov (United States)

    Disposal amperometric inhibition biosensors have been microfabricated by screen printing a tyrosinase-containing carbon ink. The decrease in the substrate (catechol) steady-state current, caused by the addition of various pesticides and herbicides, offers convenient quantitation ...

  12. Molecular Docking Studies and Anti-Tyrosinase Activity of Thai Mango Seed Kernel Extract

    Directory of Open Access Journals (Sweden)

    Patchreenart Saparpakorn

    2009-01-01

    Full Text Available The alcoholic extract from seed kernels of Thai mango (Mangifera indica L. cv. ‘Fahlun’ (Anacardiaceae and its major phenolic principle (pentagalloylglucopyranose exhibited potent, dose-dependent inhibitory effects on tyrosinase with respect to L-DOPA. Molecular docking studies revealed that the binding orientations of the phenolic principles were in the tyrosinase binding pocket and their orientations were located in the hydrophobic binding pocket surrounding the binuclear copper active site. The results indicated a possible mechanism for their anti-tyrosinase activity which may involve an ability to chelate the copper atoms which are required for the catalytic activity of tyrosinase.

  13. Tyrosinase Inhibition Type of Isolated Compounds Obtained from Pachyrhizus erosus

    Directory of Open Access Journals (Sweden)

    Endang Lukitaningsih

    2013-12-01

    Full Text Available In Indonesia, Bengkoang (Phacyrhizus erosus have been used as one of cosmetics especially as sun screening and skin whitening materials. Six active compounds in Bengkoang with antioxidant and skin whitening activities have been isolated, namely daidzein, daidzin, genistin, (8,9-furanyl-pterocarpan-3-ol, 4-(2-(furane-2-ylethyl-2-methyl-2,5-dihydro-furane-3-carbaldehyde and 2-butoxy-2,5-bis(hydroxymethyl-tetrahydrofurane-3,4-diol. According to literatures, the type of their tyrosinase inhibitory activity has not yet reported. The determination of whitening activity of each compound was evaluated by the evaluation of Lineweaver-Burk plot. The result showed that five compounds had competitive inhibitory activity and 8,9-furanyl-pterocarpan-3-ol showed a non-competitive inhibition.

  14. Inhibitory Effect of Arctigenin from Fructus Arctii Extract on Melanin Synthesis via Repression of Tyrosinase Expression

    OpenAIRE

    Park, Hwayong; Song, Kwang Hoon; Jung, Pil Mun; Kim, Ji-Eun; Ro, Hyunju; Kim, Mi Yoon; Ma, Jin Yeul

    2013-01-01

    To identify the active compound arctigenin in Fructus Arctii (dried seed of medicinal plant Arctium lappa) and to elucidate the inhibitory mechanism in melanogenesis, we analyzed melanin content and tyrosinase activity on B16BL6 murine melanoma and melan-A cell cultures. Water extracts of Fructus Arctii were shown to inhibit tyrosinase activity in vitro and melanin content in ? -melanocyte stimulating hormone-stimulated cells to similar levels as the well-known kojic acid and arbutin, respect...

  15. Oculocutaneous albinism type 1: link between mutations, tyrosinase conformational stability, and enzymatic activity.

    Science.gov (United States)

    Dolinska, Monika B; Kus, Nicole J; Farney, S Katie; Wingfield, Paul T; Brooks, Brian P; Sergeev, Yuri V

    2017-01-01

    Oculocutaneous albinism type 1 (OCA1) is an autosomal recessive disorder caused by mutations in the tyrosinase gene. Two subtypes of OCA1 have been described: severe OCA1A with complete absence of tyrosinase activity and less severe OCA1B with residual tyrosinase activity. Here, we characterize the recombinant human tyrosinase intramelanosomal domain and mutant variants, which mimic genetic changes in both subtypes of OCA1 patients. Proteins were prepared using site-directed mutagenesis, expressed in insect larvae, purified by chromatography, and characterized by enzymatic activities, tryptophan fluorescence, and Gibbs free energy changes. The OCA1A mutants showed very low protein expression and protein yield and are enzymatically inactive. Mutants mimicking OCA1B were biochemically similar to the wild type, but exhibited lower specific activities and protein stabilities. The results are consistent with clinical data, which indicates that OCA1A mutations inactivate tyrosinase and result in severe phenotype, while OCA1B mutations partially inactivate tyrosinase and result in OCA1B albinism. Published 2017. This article is a U.S. Government work and is in the public domain in the USA.

  16. Effect of inhibition on tyrosinase and melanogenesis of Agastache rugosa Kuntze by lactic acid bacteria fermentation.

    Science.gov (United States)

    Kim, Nam Young; Kwon, Hee Souk; Lee, Hyeon Yong

    2017-09-01

    This work presents the first report that A. rugosa could have tyrosinase and melanogenesis inhibition and that its activities also be improved by fermentation with Lactobacillus rhamnosus and Lactobacillus paracasei. It was found that the tyrosinase and melanogenesis inhibition was correlated with antioxidant activity of acacetin, the major biologically active substances in A. rugosa. we pursued an improvement in tyrosinase and melanogenesis inhibition of A. rugosa extract by fermentation process. A. rugosa was extracted by lactic acid fermentation process; we measured antioxidant activities and tyrosinase and melanogenesis inhibition of A. rugosa extracts. In particular, reducing power of the extract from fermentation process (FE) was measured as 0.562 (O.D.), whereas reducing power of the extracts from 70% ethanol extraction (EE) was lower than the FE as 0.496 (O.D.). Polyphenols and flavonoids in the FE were higher than the EE: 69.3 mg/g vs. 60.5 mg/g, and 187 mg/g vs. 138 mg/g. The FE was estimated as 51.04% tyrosinase inhibition and 41.88% for the EE. Similarly, melanin inhibition in melanocyte B16F10 was observed as 66.60% vs. 42.23% for the FE and EE. The increase in tyrosinase and melanogenesis inhibition activity was confirmed by high elution of acacetin through fermentation process such as 289.97 mg/100 g vs. 198.04 mg/100 g in the FE and EE. These results indicate that tyrosinase and melanogenesis inhibition activities of the extracts should be associated with antioxidant activity because acacetin is known to have strong antioxidant activity, which can also positively affect whitening activities. © 2016 Wiley Periodicals, Inc.

  17. New tyrosinase inhibitory decapeptide: Molecular insights into the role of tyrosine residues.

    Science.gov (United States)

    Ochiai, Akihito; Tanaka, Seiya; Imai, Yuta; Yoshida, Hisashi; Kanaoka, Takumi; Tanaka, Takaaki; Taniguchi, Masayuki

    2016-06-01

    Tyrosinase, a rate-limiting enzyme in melanin biosynthesis, catalyzes the hydroxylation of l-tyrosine to 3,4-dihydroxy-l-phenylalanine (l-dopa) (monophenolase reaction) and the subsequent oxidation of l-dopa to l-dopaquinone (diphenolase reaction). Thus, tyrosinase inhibitors have been proposed as skin-lightening agents; however, many of the existing inhibitors cannot be widely used in the cosmetic industry due to their high cytotoxicity and instability. On the other hand, some tyrosinase inhibitory peptides have been reported as safe. In this study, we found that the peptide TH10, which has a similar sequence to the characterized inhibitory peptide P4, strongly inhibits the monophenolase reaction with a half-maximal inhibitory concentration of 102 μM. Seven of the ten amino acid residues in TH10 were identical to P4; however, TH10 possesses one N-terminal tyrosine, whereas P4 contains three tyrosine residues located at its N-terminus, center, and C-terminus. Subsequent analysis using sequence-shuffled variants indicated that the tyrosine residues located at the N-terminus and center of P4 have little to no contribution to its inhibitory activity. Furthermore, docking simulation analysis of these peptides with mushroom tyrosinase demonstrated that the active tyrosine residue was positioned close to copper ions, suggesting that TH10 and P4 bind to tyrosinase as a substrate analogue. Copyright © 2015 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

  18. Screening of plant extracts for human tyrosinase inhibiting effects.

    Science.gov (United States)

    Kim, M; Park, J; Song, K; Kim, H G; Koh, J-S; Boo, Y C

    2012-04-01

    Screening for tyrosinase (TYR) inhibitors potentially useful for control of skin pigmentation has been hampered by the limited availability of human TYR. To overcome this hurdle, we have established human embryonic kidney (HEK293)-TYR cells that constitutively express human TYR. In the current study, we assayed human TYR inhibition activities of 50 plant extracts using the lysates of transformed HEK293-TYR cells. The strongest inhibition of human TYR was shown by the extract of Vaccinium bracteatum Thunberg, followed by the extract of Morus bombycis Koidzumi. The former extract did not inhibit mushroom TYR activity whereas significant inhibition was observed with the latter extract, demonstrating the importance of using human TYR in the screening for human TYR inhibitors. Upon liquid-liquid partitioning of the extract from V. bracteatum, the active constituents were enriched in the ethyl acetate fraction, and the subsequent preparatory thin-layer chromatography identified p-coumaric acid (PCA) as the main active constituent. The hypo-pigmentation of PCA was verified in the MelanoDerm™ Skin Model. This study demonstrates that transformed HEK293-TYR cells could expedite the discovery of human TYR-specific inhibitors from natural sources which might be useful in the control of skin pigmentation. © 2012 The Authors. ICS © 2012 Society of Cosmetic Scientists and the Société Française de Cosmétologie.

  19. Global patterns of diversity and selection in human tyrosinase gene.

    Science.gov (United States)

    Hudjashov, Georgi; Villems, Richard; Kivisild, Toomas

    2013-01-01

    Global variation in skin pigmentation is one of the most striking examples of environmental adaptation in humans. More than two hundred loci have been identified as candidate genes in model organisms and a few tens of these have been found to be significantly associated with human skin pigmentation in genome-wide association studies. However, the evolutionary history of different pigmentation genes is rather complex: some loci have been subjected to strong positive selection, while others evolved under the relaxation of functional constraints in low UV environment. Here we report the results of a global study of the human tyrosinase gene, which is one of the key enzymes in melanin production, to assess the role of its variation in the evolution of skin pigmentation differences among human populations. We observe a higher rate of non-synonymous polymorphisms in the European sample consistent with the relaxation of selective constraints. A similar pattern was previously observed in the MC1R gene and concurs with UV radiation-driven model of skin color evolution by which mutations leading to lower melanin levels and decreased photoprotection are subject to purifying selection at low latitudes while being tolerated or even favored at higher latitudes because they facilitate UV-dependent vitamin D production. Our coalescent date estimates suggest that the non-synonymous variants, which are frequent in Europe and North Africa, are recent and have emerged after the separation of East and West Eurasian populations.

  20. Wearable Wireless Tyrosinase Bandage and Microneedle Sensors: Toward Melanoma Screening.

    Science.gov (United States)

    Ciui, Bianca; Martin, Aida; Mishra, Rupesh K; Brunetti, Barbara; Nakagawa, Tatsuo; Dawkins, Thomas J; Lyu, Mengjia; Cristea, Cecilia; Sandulescu, Robert; Wang, Joseph

    2018-04-01

    Wearable bendable bandage-based sensor and a minimally invasive microneedle biosensor are described toward rapid screening of skin melanoma. These wearable electrochemical sensors are capable of detecting the presence of the tyrosinase (TYR) enzyme cancer biomarker in the presence of its catechol substrate, immobilized on the transducer surface. In the presence of the surface TYR biomarker, the immobilized catechol is rapidly converted to benzoquinone that is detected amperometrically, with a current signal proportional to the TYR level. The flexible epidermal bandage sensor relies on printing stress-enduring inks which display good resiliency against mechanical deformations, whereas the hollow microneedle device is filled with catechol-coated carbon paste for assessing tissue TYR levels. The bandage sensor can thus be used directly on the skin whereas microneedle device can reach melanoma tissues under the skin. Both wearable sensors are interfaced to an ultralight flexible electronic board, which transmits data wirelessly to a mobile device. The analytical performance of the resulting bandage and microneedle sensing systems are evaluated using TYR-containing agarose phantom gel and porcine skin. The new integrated conformal portable sensing platforms hold considerable promise for decentralized melanoma screening, and can be extended to the screening of other key biomarkers in skin moles. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Chemometric profile, antioxidant and tyrosinase inhibitory activity of Camel's foot creeper leaves (Bauhinia vahlii).

    Science.gov (United States)

    Panda, Pritipadma; Dash, Priyanka; Ghosh, Goutam

    2018-03-01

    The present study is the first effort to a comprehensive evaluation of antityrosinase activity and chemometric analysis of Bauhinia vahlii. The experimental results revealed that the methanol extract of Bauhinia vahlii (BVM) possesses higher polyphenolic compounds and total antioxidant activity than those reported elsewhere for other more conventionally and geographically different varieties. The BVM contain saturated fatty acids such as hexadecanoic acid (10.15%), octadecanoic acid (1.97%), oleic acid (0.61%) and cis-vaccenic acid (2.43%) along with vitamin E (12.71%), α-amyrin (9.84%), methyl salicylate (2.39%) and β-sitosterol (17.35%), which were mainly responsible for antioxidant as well as tyrosinase inhibitory activity. Tyrosinase inhibitory activity of this extract was comparable to that of Kojic acid. These findings suggested that the B. vahlii leaves could be exploited as potential source of natural antioxidant and tyrosinase inhibitory agent, as well.

  2. Tyrosinase inhibitory effects and antioxidative activities of saponins from Xanthoceras Sorbifolia nutshell.

    Directory of Open Access Journals (Sweden)

    Hongmei Zhang

    Full Text Available Certain saponins are bioactive compounds with anticancer, antivirus and antioxidant activities. This paper discussed inhibitory effects of saponins from Xanthoceras Sorbifolia on tyrosinase, through the research of the rate of tyrosinase catalyzed L-DOPA oxidation. The inhibition rate of tyrosinase activity presented non-linear changes with the saponins concentration. The rate reached 52.0% when the saponins concentration was 0.96 mg/ml. Antioxidant activities of saponins from Xanthoceras Sorbifolia were evaluated by using hydroxyl and superoxide radical scavenging assays. The hydroxyl radical scavenging effects of the saponins were 15.5-68.7%, respectively at the concentration of 0.18-2.52 mg/ml. The superoxide radical scavenging activity reduced from 96.6% to 7.05% with the time increasing at the concentration of 1.44 mg/ml. All the above antioxidant evaluation indicated that saponins from Xanthoceras Sorbifolia exhibited good antioxidant activity in a concentration- dependent manner.

  3. Condensed Tannins from Longan Bark as Inhibitor of Tyrosinase: Structure, Activity, and Mechanism.

    Science.gov (United States)

    Chai, Wei-Ming; Huang, Qian; Lin, Mei-Zhen; Ou-Yang, Chong; Huang, Wen-Yang; Wang, Ying-Xia; Xu, Kai-Li; Feng, Hui-Ling

    2018-01-31

    In this study, the content, structure, antityrosinase activity, and mechanism of longan bark condensed tannins were evaluated. The findings obtained from mass spectrometry demonstrated that longan bark condensed tannins were mixtures of procyanidins, propelargonidins, prodelphinidins, and their acyl derivatives (galloyl and p-hydroxybenzoate). The enzyme analysis indicated that these mixtures were efficient, reversible, and mixed (competitive is dominant) inhibitor of tyrosinase. What's more, the mixtures showed good inhibitions on proliferation, intracellular enzyme activity and melanogenesis of mouse melanoma cells (B 16 ). From molecular docking, the results showed the interactions between inhibitors and tyrosinase were driven by hydrogen bond, electrostatic, and hydrophobic interactions. In addition, high levels of total phenolic and extractable condensed tannins suggested that longan bark might be a good source of tyrosinase inhibitor. This study would offer theoretical basis for the development of longan bark condensed tannins as novel food preservatives and medicines of skin diseases.

  4. Enzymatic synthesis of arbutin undecylenic acid ester and its inhibitory effect on mushroom tyrosinase.

    Science.gov (United States)

    Tokiwa, Y; Kitagawa, M; Raku, T

    2007-03-01

    A novel tyrosinase inhibitor, an arbutin derivative having undecylenic acid at the 6-position of its glucose moiety, was enzymatically synthesized. Its inhibitory activity was studied in vitro by using catechol and phenol as substrates. The IC(50) value of the arbutin ester on tyrosinase using catechol (4 x 10(-4) M) was 1% of that when arbutin (4 x 10(-2) M) was used. Using phenol, IC(50) of the arbutin ester (3 x 10(-4) M) as substrate was 10% of that of arbutin (3 x 10(-3) M). These results suggest that the arbutin ester inhibits the latter part of the tyrosinase reaction, which consists of hydroxylation and oxidation.

  5. Computational analysis of histidine mutations on the structural stability of human tyrosinases leading to albinism insurgence.

    Science.gov (United States)

    Hassan, Mubashir; Abbas, Qamar; Raza, Hussain; Moustafa, Ahmed A; Seo, Sung-Yum

    2017-07-25

    Misfolding and structural alteration in proteins lead to serious malfunctions and cause various diseases in humans. Mutations at the active binding site in tyrosinase impair structural stability and cause lethal albinism by abolishing copper binding. To evaluate the histidine mutational effect, all mutated structures were built using homology modelling. The protein sequence was retrieved from the UniProt database, and 3D models of original and mutated human tyrosinase sequences were predicted by changing the residual positions within the target sequence separately. Structural and mutational analyses were performed to interpret the significance of mutated residues (N 180 , R 202 , Q 202 , R 211 , Y 363 , R 367 , Y 367 and D 390 ) at the active binding site of tyrosinases. CSpritz analysis depicted that 23.25% residues actively participate in the instability of tyrosinase. The accuracy of predicted models was confirmed through online servers ProSA-web, ERRAT score and VERIFY 3D values. The theoretical pI and GRAVY generated results also showed the accuracy of the predicted models. The CCA negative correlation results depicted that the replacement of mutated residues at His within the active binding site disturbs the structural stability of tyrosinases. The predicted CCA scores of Tyr 367 (-0.079) and Q/R 202 (0.032) revealed that both mutations have more potential to disturb the structural stability. MD simulation analyses of all predicted models justified that Gln 202 , Arg 202 , Tyr 367 and D 390 replacement made the protein structures more susceptible to destabilization. Mutational results showed that the replacement of His with Q/R 202 and Y/R 363 has a lethal effect and may cause melanin associated diseases such as OCA1. Taken together, our computational analysis depicts that the mutated residues such as Q/R 202 and Y/R 363 actively participate in instability and misfolding of tyrosinases, which may govern OCA1 through disturbing the melanin biosynthetic pathway.

  6. Synthesis, kinetic mechanism and docking studies of vanillin derivatives as inhibitors of mushroom tyrosinase.

    Science.gov (United States)

    Ashraf, Zaman; Rafiq, Muhammad; Seo, Sung-Yum; Babar, Mustafeez Mujtaba; Zaidi, Najam-us-Sahar Sadaf

    2015-09-01

    The purpose of the present study was to discover the extent of contribution to antityrosinase activity by adding hydroxy substituted benzoic acid, cinnamic acid and piperazine residues to vanillin. The study showed the transformation of vanillin into esters as shown in (4a-4d), (6a-6b), and (8a-8b). In addition, the relationship between structures of these esters and their mushroom tyrosinase inhibitory activity was explored. The kinetics of inhibition on mushroom tyrosinase by these esters was also investigated. It was found that hydroxyl substituted benzoic acid derivatives were weak inhibitors; however hydroxy or chloro substituted cinnamic acid and piperazine substituted derivatives were able to induce significant tyrosinase inhibition. The mushroom tyrosinase (PDBID 2ZWE) was docked with synthesized vanillin derivatives and their calculated binding energies were compared with experimental IC50 values which provided positive correlation. The most potent derivative 2-(4-formyl-2-methoxyphenoxy)-2-oxoethyl (2E)-3-(4-hydroxyphenyl)prop-2-enoate (6a) possesses hydroxy substituted cinnamic acid scaffold having IC50 value 16.13 μM with binding energy of -7.2 kcal/mol. The tyrosinase inhibitory activity of (6a) is comparable with standard kojic acid. Kinetic analysis indicated that compound 6a was mixed-type tyrosinase inhibitor with inhibition constant values Ki (13 μM) and Ki' (53 μM) and formed reversible enzyme inhibitor complex. The active vanillin analog (6a) was devoid of toxic effects as shown in cytotoxic studies. Copyright © 2015 Elsevier Ltd. All rights reserved.

  7. Crystal structure of Agaricus bisporus mushroom tyrosinase: identity of the tetramer subunits and interaction with tropolone.

    Science.gov (United States)

    Ismaya, Wangsa T; Rozeboom, Henriëtte J; Weijn, Amrah; Mes, Jurriaan J; Fusetti, Fabrizia; Wichers, Harry J; Dijkstra, Bauke W

    2011-06-21

    Tyrosinase catalyzes the conversion of phenolic compounds into their quinone derivatives, which are precursors for the formation of melanin, a ubiquitous pigment in living organisms. Because of its importance for browning reactions in the food industry, the tyrosinase from the mushroom Agaricus bisporus has been investigated in depth. In previous studies the tyrosinase enzyme complex was shown to be a H(2)L(2) tetramer, but no clues were obtained of the identities of the subunits, their mode of association, and the 3D structure of the complex. Here we unravel this tetramer at the molecular level. Its 2.3 Å resolution crystal structure is the first structure of the full fungal tyrosinase complex. The complex comprises two H subunits of ∼392 residues and two L subunits of ∼150 residues. The H subunit originates from the ppo3 gene and has a fold similar to other tyrosinases, but it is ∼100 residues larger. The L subunit appeared to be the product of orf239342 and has a lectin-like fold. The H subunit contains a binuclear copper-binding site in the deoxy-state, in which three histidine residues coordinate each copper ion. The side chains of these histidines have their orientation fixed by hydrogen bonds or, in the case of His85, by a thioether bridge with the side chain of Cys83. The specific tyrosinase inhibitor tropolone forms a pre-Michaelis complex with the enzyme. It binds near the binuclear copper site without directly coordinating the copper ions. The function of the ORF239342 subunits is not known. Carbohydrate binding sites identified in other lectins are not conserved in ORF239342, and the subunits are over 25 Å away from the active site, making a role in activity unlikely. The structures explain how calcium ions stabilize the tetrameric state of the enzyme.

  8. Inhibitory and Acceleratory Effects of Inonotus obliquus on Tyrosinase Activity and Melanin Formation in B16 Melanoma Cells

    Directory of Open Access Journals (Sweden)

    Zheng-Fei Yan

    2014-01-01

    Full Text Available The aim of the present study is to preliminarily investigate the antimelanogenesis effect of Inonotus obliquus extracts by cell-free mushroom tyrosinase assay. It was found that petroleum ether and n-butanol extracts might contain unknown potential tyrosinase inhibitors, while its ethyl acetate extract might contain some unknown accelerators. Six compounds were isolated and their structures were identified by interpretation of NMR data and nicotinic acid was first discovered in Inonotus obliquus. In cells testing, betulin and trametenolic acid decreased tyrosinase activity and melanin content, while inotodiol and lanosterol significantly increased tyrosinase activity and melanin content, showing an AC⁡50 of 9.74 and 8.43 μM, respectively. Nicotinie acid, 3β,22,25-trihydroxy-lanosta-8-ene, had a little or no effect on tyrosinase. Betulin exhibited a mode of noncompetitive inhibition with a KI=KIS of 0.4 μM on tyrosinase activity showing an IC50 of 5.13 μM and being more effective than kojic acid (6.43 μM, and trametenolic acid exhibited a mode of mixed inhibition with a KI of 0.9 μM, KIS of 0.5 μM, and an IC50 of 7.25 μM. We proposed betulin and trametenolic acid as a new candidate of potent tyrosinase inhibitors and inotodiol and lanosterol as accelerators that could be used as therapeutic agent.

  9. The Effect of D-(−-arabinose on Tyrosinase: An Integrated Study Using Computational Simulation and Inhibition Kinetics

    Directory of Open Access Journals (Sweden)

    Hong-Jian Liu

    2012-01-01

    Full Text Available Tyrosinase is a ubiquitous enzyme with diverse physiologic roles related to pigment production. Tyrosinase inhibition has been well studied for cosmetic, medicinal, and agricultural purposes. We simulated the docking of tyrosinase and D-(−-arabinose and found a binding energy of −4.5 kcal/mol for theup-formof D-(−-arabinose and −4.4 kcal/mol for thedown-form of D-(−-arabinose. The results of molecular dynamics simulation suggested that D-(−-arabinose interacts mostly with HIS85, HIS259, and HIS263, which are believed to be in the active site. Our kinetic study showed that D-(−-arabinose is a reversible, mixed-type inhibitor of tyrosinase (α-value =6.11±0.98, Ki=0.21±0.19 M. Measurements of intrinsic fluorescence showed that D-(−-arabinose induced obvious tertiary changes to tyrosinase (binding constant K=1.58±0.02 M−1, binding number n=1.49±0.06. This strategy of predicting tyrosinase inhibition based on specific interactions of aldehyde and hydroxyl groups with the enzyme may prove useful for screening potential tyrosinase inhibitors.

  10. Chemical components and tyrosinase inhibitors from the twigs of Artocarpus heterophyllus.

    Science.gov (United States)

    Zheng, Zong-Ping; Chen, Sibao; Wang, Shiyun; Wang, Xia-Chang; Cheng, Ka-Wing; Wu, Jia-Jun; Yang, Dajiang; Wang, Mingfu

    2009-08-12

    An HPLC method was developed and validated to compare the chemical profiles and tyrosinase inhibitors in the woods, twigs, roots, and leaves of Artocarpus heterophyllus . Five active tyrosinase inhibitors including dihydromorin, steppogenin, norartocarpetin, artocarpanone, and artocarpesin were used as marker compounds in this HPLC method. It was discovered that the chemical profiles of A. heterophyllus twigs and woods are quite different. Systematic chromatographic methods were further applied to purify the chemicals in the twigs of A. heterophyllus. Four new phenolic compounds, including one isoprenylated 2-arylbenzofuran derivative, artoheterophyllin A (1), and three isoprenylated flavonoids, artoheterophyllin B (2), artoheterophyllin C (3), and artoheterophyllin D (4), together with 16 known compounds, were isolated from the ethanol extract of the twigs of A. heterophyllus. The structures of compounds 1-4 were elucidated by spectroscopic analysis. However, the four new compounds did not show significant inhibitory activities against mushroom tyrosinase compared to kojic acid. It was found that similar compounds, such as norartocarpetin and artocarpesin in the twigs and woods of A. heterophyllus, contributed to their tyrosinase inhibitory activity.

  11. Potent microbial and tyrosinase inhibitors from stem bark of Bauhinia rufescens (Fabaceae).

    Science.gov (United States)

    Muhammad, Aminu; Sirat, Hasnah Mohd

    2013-10-01

    The stem bark extracts of Bauhinia rufescens Lam. (Fabaceae) yielded 6-methoxy-7-methyl-8-hydroxydibenz[b,f]oxepin, alpha-amyrin acetate, beta-sitosterol 3-O-beta-D-xylopyranoside, 4-(2'-Hydroxyphenethyl)-5-methoxy-2-methylphenol, menisdaurin and sequoyitol. Their structures were determined using spectroscopic methods and comparisons with the literature data. For the antimicrobial assay Gram-positive and Gram-negative bacterial and fungal strains were tested, while the tyrosinase inhibition assay utilized L-DOPA as a substrate for the tyrosinase enzyme. 6-Methoxy-7-methyl-8-hydroxydibenz[b,f]oxepin, a-amyrin acetate, beta-sitosterol 3-O-D-xylopyranoside, menisdaurin and sequoyitol showed weak to moderate activities with minimum inhibition concentration (MIC) values in the range of 112.5-900 microg/mL against all bacterial strains, while the MIC values for the fungal strains were in the range of 28.1-450 microg/mL. In the tyrosinase inhibition assay, a-amyrin acetate was found to be moderately active against tyrosinase with an inhibition of 62% at 0.1 mg/mL. This activity was lower than that of the positive control, kojic acid (85%).

  12. Substrate-Dependent Kinetics in Tyrosinase-based Biosensing: Amperometry vs. Spectrophotometry

    NARCIS (Netherlands)

    Rassaei, Liza; Cui, Jin; Goluch, E.D.; Lemay, Serge Joseph Guy

    2012-01-01

    Despite the broad use of enzymes in electroanalytical biosensors, the influence of enzyme kinetics on the function of prototype sensors is often overlooked or neglected. In the present study, we employ amperometry as an alternative or complementary method to study the kinetics of tyrosinase, whose

  13. Antioxidant, Iron Chelating and Tyrosinase Inhibitory Activities of Extracts from Talinum triangulare Leach Stem

    Directory of Open Access Journals (Sweden)

    Ana Paula Oliveira Amorim

    2013-07-01

    Full Text Available The aim of this work is to evaluate the antioxidant activity against the radical species DPPH, the reducing capacity against Fe II ions, and the inhibitory activity on the tyrosinase enzyme of the T. triangulare. Hydromethanolic crude extract provided two fractions after the liquid/liquid partition with chloroform. The Folin-Ciocalteu method determined the total phenolic content of the crude extract (CE and the hydromethanolic fraction (Fraction 1, resulting in a concentration of 0.5853 g/100 g for Fraction 1, and 0.1400 g/100 g for the CE. Taking into account the results of the DPPH, the free radical scavenging capacity was confirmed. The formation of complexes with Fe II ions was evaluated by UV/visible spectrometry; results showed that CE has complexing power similar to the positive control (Gingko biloba extract.The inhibitory capacity of samples against the tyrosinase enzyme was determined by the oxidation of L-DOPA, providing IC50 values of 13.3 μg·mL−1 (CE and 6.6 μg·mL−1 (Fraction 1. The values indicate that Fraction 1 was more active and showed a higher inhibitory power on the tyrosinase enzyme than the ascorbic acid, used as positive control. The hydromethanolic extract of T. triangulare proved to have powerful antioxidant activity and to inhibit the tyrosinase enzyme; its potential is increased after the partition with chloroform.

  14. Microbial Tyrosinases: Promising Enzymes for Pharmaceutical, Food Bioprocessing, and Environmental Industry

    Directory of Open Access Journals (Sweden)

    Kamal Uddin Zaidi

    2014-01-01

    Full Text Available Tyrosinase is a natural enzyme and is often purified to only a low degree and it is involved in a variety of functions which mainly catalyse the o-hydroxylation of monophenols into their corresponding o-diphenols and the oxidation of o-diphenols to o-quinones using molecular oxygen, which then polymerizes to form brown or black pigments. The synthesis of o-diphenols is a potentially valuable catalytic ability and thus tyrosinase has attracted a lot of attention with respect to industrial applications. In environmental technology it is used for the detoxification of phenol-containing wastewaters and contaminated soils, as biosensors for phenol monitoring, and for the production of L-DOPA in pharmaceutical industries, and is also used in cosmetic and food industries as important catalytic enzyme. Melanin pigment synthesized by tyrosinase has found applications for protection against radiation cation exchangers, drug carriers, antioxidants, antiviral agents, or immunogen. The recombinant V. spinosum tryosinase protein can be used to produce tailor-made melanin and other polyphenolic materials using various phenols and catechols as starting materials. This review compiles the recent data on biochemical and molecular properties of microbial tyrosinases, underlining their importance in the industrial use of these enzymes. After that, their most promising applications in pharmaceutical, food processing, and environmental fields are presented.

  15. Albinism in the american mink (Neovison vison) is associated with a tyrosinase nonsense mutation

    DEFF Research Database (Denmark)

    Anistoroaei, Razvan Marian; Fredholm, Merete; Christensen, Knud

    2008-01-01

    Albino phenotypes are documented in various species including the American mink. In other species the albino phenotypes are associated with tyrosinase (TYR) gene mutations; therefore TYR was considered the candidate gene for albinism in mink. Four microsatellite markers were chosen in the prodicted...

  16. Determination of the Bridging Ligand in the Active Site of Tyrosinase

    Directory of Open Access Journals (Sweden)

    Congming Zou

    2017-10-01

    Full Text Available Tyrosinase is a type-3 copper enzyme that is widely distributed in plants, fungi, insects, and mammals. Developing high potent inhibitors against tyrosinase is of great interest in diverse fields including tobacco curing, food processing, bio-insecticides development, cosmetic development, and human healthcare-related research. In the crystal structure of Agaricus bisporus mushroom tyrosinase, there is an oxygen atom bridging the two copper ions in the active site. It is unclear whether the identity of this bridging oxygen is a water molecule or a hydroxide anion. In the present study, we theoretically determine the identity of this critical bridging oxygen by performing first-principles hybrid quantum mechanics/molecular mechanics/Poisson-Boltzmann-surface area (QM/MM-PBSA calculations along with a thermodynamic cycle that aim to improve the accuracy. Our results show that the binding with water molecule is energy favored and the QM/MM-optimized structure is very close to the crystal structure, whereas the binding with hydroxide anions causes the increase of energy and significant structural changes of the active site, indicating that the identity of the bridging oxygen must be a water molecule rather than a hydroxide anion. The different binding behavior between water and hydroxide anions may explain why molecules with a carboxyl group or too many negative charges have lower inhibitory activity. In light of this, the design of high potent active inhibitors against tyrosinase should satisfy both the affinity to the copper ions and the charge neutrality of the entire molecule.

  17. Use of Mushroom Tyrosinase to Introduce Michaelis-Menten Enzyme Kinetics to Biochemistry Students

    Science.gov (United States)

    Flurkey, William H.; Inlow, Jennifer K.

    2017-01-01

    An inexpensive enzyme kinetics laboratory exercise for undergraduate biochemistry students is described utilizing tyrosinase from white button mushrooms. The exercise can be completed in one or two three-hour lab sessions. The optimal amounts of enzyme, substrate (catechol), and inhibitor (kojic acid) are first determined, and then kinetic data is…

  18. Tyrosinase-Mediated Construction of a Silk Fibroin/Elastin Nanofiber Bioscaffold.

    Science.gov (United States)

    Hong, Yanqing; Zhu, Xueke; Wang, Ping; Fu, Haitian; Deng, Chao; Cui, Li; Wang, Qiang; Fan, Xuerong

    2016-04-01

    Elastin has characteristics of elasticity, biological activity, and mechanical stability. In the present work, tyrosinase-mediated construction of a bioscaffold with silk fibroin and elastin was carried out, aiming at developing a novel medical biomaterial. The efficiency of enzymatic oxidation of silk fibroin and the covalent reaction between fibroin and elastin were examined by spectrophotometry, sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), and size exclusion chromatography (SEC). The properties of composite air-dried and nanofiber scaffolds were investigated. The results reveal that elastin was successfully bonded to silk fibroins, resulting in an increase in molecular weight of fibroin proteins. ATR-FTIR spectra indicated that tyrosinase treatment impacted the conformational structure of fibroin-based membrane. The thermal behaviors and mechanical properties of the tyrosinase-treated scaffolds were also improved compared with the untreated group. NIH/3T3 cells exhibited optimum densities when grown on the nanofiber scaffold, implying that the nanofiber scaffold has enhanced biocompatibility compared to the air-dried scaffold. A biological nanofiber scaffold constructed from tyrosinase-treated fibroin and elastin could potentially be utilized in biomedical applications.

  19. Characterization of a New Flavone and Tyrosinase Inhibition Constituents from the Twigs of Morus alba L.

    Science.gov (United States)

    Zhang, Long; Tao, Guanjun; Chen, Jie; Zheng, Zong-Ping

    2016-09-02

    The twigs of Morus alba L. were found to show strong tyrosinase inhibition activity, and the responsible active components in the extract were further investigated in this study. A flavone, named morusone (1), and sixteen known compounds 2-17 were isolated from M. alba twigs and their structures were identified by interpretation of the corresponding ESI-MS and NMR spectral data. In the tyrosinase inhibitory test, the compounds steppogenin (IC50 0.98 ± 0.01 µM), 2,4,2',4'-tetrahydroxychalcone (IC50 0.07 ± 0.02 µM), morachalcone A (IC50 0.08 ± 0.02 µM), oxyresveratrol (IC50 0.10 ± 0.01 µM), and moracin M (8.00 ± 0.22 µM) exhibited significant tyrosinase inhibition activities, much stronger than that of the positive control kojic acid. These results suggest that M. alba twig extract should served as a good source of natural tyrosinase inhibitors for use in foods as antibrowning agents or in cosmetics as skin-whitening agents.

  20. Characterization of a New Flavone and Tyrosinase Inhibition Constituents from the Twigs of Morus alba L.

    Directory of Open Access Journals (Sweden)

    Long Zhang

    2016-09-01

    Full Text Available The twigs of Morus alba L. were found to show strong tyrosinase inhibition activity, and the responsible active components in the extract were further investigated in this study. A flavone, named morusone (1, and sixteen known compounds 2–17 were isolated from M. alba twigs and their structures were identified by interpretation of the corresponding ESI-MS and NMR spectral data. In the tyrosinase inhibitory test, the compounds steppogenin (IC50 0.98 ± 0.01 µM, 2,4,2′,4′-tetrahydroxychalcone (IC50 0.07 ± 0.02 µM, morachalcone A (IC50 0.08 ± 0.02 µM, oxyresveratrol (IC50 0.10 ± 0.01 µM, and moracin M (8.00 ± 0.22 µM exhibited significant tyrosinase inhibition activities, much stronger than that of the positive control kojic acid. These results suggest that M. alba twig extract should served as a good source of natural tyrosinase inhibitors for use in foods as antibrowning agents or in cosmetics as skin-whitening agents.

  1. Large-scale recombinant expression and purificatoin of human tyrosinase suitabel for structural studies

    NARCIS (Netherlands)

    Lai, X.; Soler-Lopez, M.; Wichers, H.J.; Dijkstra, Bouke

    2016-01-01

    Human tyrosinase (TYR) is a glycoprotein that initiates the first two reactions in the melanin biosynthesis pathway. Mutations in its encoding gene cause Oculocutaneous Albinism type I (OCA1), the most severe form of albinism, which is a group of autosomal recessive disorders characterized by

  2. T Cell Receptors that Recognize the Tyrosinase Tumor Antigen | NCI Technology Transfer Center | TTC

    Science.gov (United States)

    The National Cancer Institute, Surgery Branch, Tumor Immunology Section, is seeking statements of capability or interest from parties interested in collaborative research to further develop, evaluate, or commercialize T Cells Attacking Cancer: T Cell Receptors that Recognize the Tyrosinase Tumor Antigen

  3. IMPROVED SELECTIVE ELECTROCATALYTIC OXIDATION OF PHENOLS BY TYROSINASE-BASED CARBON PASTE ELECTRODE BIOSENSOR

    Science.gov (United States)

    Tyrosinase-based carbon paste electrodes are evaluated with respect to the viscosity and polarity of the binder liquids. The electrodes constructed using a lower viscosity mineral oil yielded a greater response to phenol and catechol than those using a higher viscosity oil of s...

  4. Aqueous humor tyrosinase activity is indicative of iris melanocyte toxicity.

    Science.gov (United States)

    Mahanty, Sarmistha; Kawali, Ankush A; Dakappa, Shruthi Shirur; Mahendradas, Padmamalini; Kurian, Mathew; Kharbanda, Varun; Shetty, Rohit; Setty, Subba Rao Gangi

    2017-09-01

    Antibiotics such as fluoroquinolones (FQLs) are commonly used to treat ocular infections but are also known to cause dermal melanocyte toxicity. The release of dispersed pigments from the iris into the aqueous humor has been considered a possible ocular side effect of the systemic administration of FQLs such as Moxifloxacin, and this condition is known as bilateral acute iris transillumination (BAIT). Bilateral acute depigmentation of iris (BADI) is a similar condition, with iris pigment released into the aqueous, but it has not been reported as a side effect of FQL. Iris pigments are synthesized by the melanogenic enzyme tyrosinase (TYR) and can be detected but not quantified by using slit-lamp biomicroscopy. The correlation between dispersed pigments in the aqueous and the extent of melanocyte toxicity due to topical antibiotics in vivo is not well studied. Here, we aimed to study the effect of topical FQLs on iris tissue, the pigment release in the aqueous humor and the development of clinically evident iris atrophic changes. We evaluated this process by measuring the activity of TYR in the aqueous humor of 82 healthy eyes undergoing cataract surgery following topical application of FQLs such as Moxifloxacin (27 eyes, preservative-free) or Ciprofloxacin (29 eyes, with preservative) or the application of non-FQL Tobramycin (26 eyes, with preservative) as a control. In addition, the patients were questioned and examined for ocular side effects in pre- and post-operative periods. Our data showed a significantly higher mean TYR activity in the aqueous humor of Ciprofloxacin-treated eyes compared to Moxifloxacin- (preservative free, p iris melanocytes. However, the reduced TYR activity in the aqueous of Moxifloxacin-treated eyes was possibly due to the presence of a higher drug concentration, which inhibits TYR activity. Consistently, immunoblotting analysis of the aqueous humor from both Ciprofloxacin- and Moxifloxacin-treated eyes showed the presence of soluble

  5. A three-dimensional model of mammalian tyrosinase active site accounting for loss of function mutations.

    Science.gov (United States)

    Schweikardt, Thorsten; Olivares, Concepción; Solano, Francisco; Jaenicke, Elmar; García-Borrón, José Carlos; Decker, Heinz

    2007-10-01

    Tyrosinases are the first and rate-limiting enzymes in the synthesis of melanin pigments responsible for colouring hair, skin and eyes. Mutation of tyrosinases often decreases melanin production resulting in albinism, but the effects are not always understood at the molecular level. Homology modelling of mouse tyrosinase based on recently published crystal structures of non-mammalian tyrosinases provides an active site model accounting for loss-of-function mutations. According to the model, the copper-binding histidines are located in a helix bundle comprising four densely packed helices. A loop containing residues M374, S375 and V377 connects the CuA and CuB centres, with the peptide oxygens of M374 and V377 serving as hydrogen acceptors for the NH-groups of the imidazole rings of the copper-binding His367 and His180. Therefore, this loop is essential for the stability of the active site architecture. A double substitution (374)MS(375) --> (374)GG(375) or a single M374G mutation lead to a local perturbation of the protein matrix at the active site affecting the orientation of the H367 side chain, that may be unable to bind CuB reliably, resulting in loss of activity. The model also accounts for loss of function in two naturally occurring albino mutations, S380P and V393F. The hydroxyl group in S380 contributes to the correct orientation of M374, and the substitution of V393 for a bulkier phenylalanine sterically impedes correct side chain packing at the active site. Therefore, our model explains the mechanistic necessity for conservation of not only active site histidines but also adjacent amino acids in tyrosinase.

  6. Albinism-causing mutations in recombinant human tyrosinase alter intrinsic enzymatic activity.

    Science.gov (United States)

    Dolinska, Monika B; Kovaleva, Elena; Backlund, Peter; Wingfield, Paul T; Brooks, Brian P; Sergeev, Yuri V

    2014-01-01

    Tyrosinase (TYR) catalyzes the rate-limiting, first step in melanin production and its gene (TYR) is mutated in many cases of oculocutaneous albinism (OCA1), an autosomal recessive cause of childhood blindness. Patients with reduced TYR activity are classified as OCA1B; some OCA1B mutations are temperature-sensitive. Therapeutic research for OCA1 has been hampered, in part, by the absence of purified, active, recombinant wild-type and mutant human enzymes. The intra-melanosomal domain of human tyrosinase (residues 19-469) and two OCA1B related temperature-sensitive mutants, R422Q and R422W were expressed in insect cells and produced in T. ni larvae. The short trans-membrane fragment was deleted to avoid potential protein insolubility, while preserving all other functional features of the enzymes. Purified tyrosinase was obtained with a yield of >1 mg per 10 g of larval biomass. The protein was a monomeric glycoenzyme with maximum enzyme activity at 37°C and neutral pH. The two purified mutants when compared to the wild-type protein were less active and temperature sensitive. These differences are associated with conformational perturbations in secondary structure. The intramelanosomal domains of recombinant wild-type and mutant human tyrosinases are soluble monomeric glycoproteins with activities which mirror their in vivo function. This advance allows for the structure - function analyses of different mutant TYR proteins and correlation with their corresponding human phenotypes; it also provides an important tool to discover drugs that may improve tyrosinase activity and treat OCA1.

  7. Tyrosinase degradation is prevented when EDEM1 lacks the intrinsically disordered region.

    Directory of Open Access Journals (Sweden)

    Marioara B Marin

    Full Text Available EDEM1 is a mannosidase-like protein that recruits misfolded glycoproteins from the calnexin/calreticulin folding cycle to downstream endoplasmic reticulum associated degradation (ERAD pathway. Here, we investigate the role of EDEM1 in the processing of tyrosinase, a tumour antigen overexpressed in melanoma cells. First, we analyzed and modeled EDEM1 major domains. The homology model raised on the crystal structures of human and Saccharomyces cerevisiae ER class I α1,2-mannosidases reveals that the major mannosidase domain located between aminoacids 121-598 fits with high accuracy. We have further identified an N-terminal region located between aminoacids 40-119, predicted to be intrinsically disordered (ID and susceptible to adopt multiple conformations, hence facilitating protein-protein interactions. To investigate these two domains we have constructed an EDEM1 deletion mutant lacking the ID region and a triple mutant disrupting the glycan-binding domain and analyzed their association with tyrosinase. Tyrosinase is a glycoprotein partly degraded endogenously by ERAD and the ubiquitin proteasomal system. We found that the degradation of wild type and misfolded tyrosinase was enhanced when EDEM1 was overexpressed. Glycosylated and non-glycosylated mutants co-immunoprecipitated with EDEM1 even in the absence of its intact mannosidase-like domain, but not when the ID region was deleted. In contrast, calnexin and SEL 1L associated with the deletion mutant. Our data suggest that the ID region identified in the N-terminal end of EDEM1 is involved in the binding of glycosylated and non-glycosylated misfolded proteins. Accelerating tyrosinase degradation by EDEM1 overexpression may lead to an efficient antigen presentation and enhanced elimination of melanoma cells.

  8. Albinism-causing mutations in recombinant human tyrosinase alter intrinsic enzymatic activity.

    Directory of Open Access Journals (Sweden)

    Monika B Dolinska

    Full Text Available Tyrosinase (TYR catalyzes the rate-limiting, first step in melanin production and its gene (TYR is mutated in many cases of oculocutaneous albinism (OCA1, an autosomal recessive cause of childhood blindness. Patients with reduced TYR activity are classified as OCA1B; some OCA1B mutations are temperature-sensitive. Therapeutic research for OCA1 has been hampered, in part, by the absence of purified, active, recombinant wild-type and mutant human enzymes.The intra-melanosomal domain of human tyrosinase (residues 19-469 and two OCA1B related temperature-sensitive mutants, R422Q and R422W were expressed in insect cells and produced in T. ni larvae. The short trans-membrane fragment was deleted to avoid potential protein insolubility, while preserving all other functional features of the enzymes. Purified tyrosinase was obtained with a yield of >1 mg per 10 g of larval biomass. The protein was a monomeric glycoenzyme with maximum enzyme activity at 37°C and neutral pH. The two purified mutants when compared to the wild-type protein were less active and temperature sensitive. These differences are associated with conformational perturbations in secondary structure.The intramelanosomal domains of recombinant wild-type and mutant human tyrosinases are soluble monomeric glycoproteins with activities which mirror their in vivo function. This advance allows for the structure - function analyses of different mutant TYR proteins and correlation with their corresponding human phenotypes; it also provides an important tool to discover drugs that may improve tyrosinase activity and treat OCA1.

  9. New Whitening Constituents from Taiwan-Native Pyracantha koidzumii: Structures and Tyrosinase Inhibitory Analysis in Human Epidermal Melanocytes

    Directory of Open Access Journals (Sweden)

    Rong-Dih Lin

    2015-12-01

    Full Text Available Nontoxic natural products useful in skin care cosmetics are of considerable interest. Tyrosinase is a rate-limiting enzyme for which its inhibitor is useful in developing whitening cosmetics. Pyracantha koidzumii (Hayata Rehder is an endemic species in Taiwan that exhibits tyrosinase-inhibitory activity. To find new active natural compounds from P. koidzumii, we performed bioguided isolation and studied the related activity in human epidermal melanocytes. In total, 13 compounds were identified from P. koidzumii in the present study, including two new compounds, 3,6-dihydroxy-2,4-dimethoxy-dibenzofuran (9 and 3,4-dihydroxy-5-methoxybiphenyl-2ʹ-O-β-d-glucopyranoside (13, as well as 11 known compounds. The new compound 13 exhibited maximum potency in inhibiting cellular tyrosinase activity, the protein expression of cellular tyrosinase and tyrosinase-related protein-2, as well as the mRNA expression of Paired box 3 and microphthalmia-associated transcription factor in a concentration-dependent manner. In the enzyme kinetic assay, the new compound 13 acted as an uncompetitive mixed-type inhibitor against the substrate l-3,4-dihydroxyphenylalanine and had a Km value against this substrate of 0.262 mM, as calculated using the Lineweaver–Burk plots. Taken together, our findings show compound 13 exhibits tyrosinase inhibition in human melanocytes and compound 13 may be a potential candidate for use in cosmetics.

  10. New Whitening Constituents from Taiwan-Native Pyracantha koidzumii: Structures and Tyrosinase Inhibitory Analysis in Human Epidermal Melanocytes

    Science.gov (United States)

    Lin, Rong-Dih; Chen, Mei-Chuan; Liu, Yan-Ling; Lin, Yi-Tzu; Lu, Mei-Kuang; Hsu, Feng-Lin; Lee, Mei-Hsien

    2015-01-01

    Nontoxic natural products useful in skin care cosmetics are of considerable interest. Tyrosinase is a rate-limiting enzyme for which its inhibitor is useful in developing whitening cosmetics. Pyracantha koidzumii (Hayata) Rehder is an endemic species in Taiwan that exhibits tyrosinase-inhibitory activity. To find new active natural compounds from P. koidzumii, we performed bioguided isolation and studied the related activity in human epidermal melanocytes. In total, 13 compounds were identified from P. koidzumii in the present study, including two new compounds, 3,6-dihydroxy-2,4-dimethoxy-dibenzofuran (9) and 3,4-dihydroxy-5-methoxybiphenyl-2ʹ-O-β-d-glucopyranoside (13), as well as 11 known compounds. The new compound 13 exhibited maximum potency in inhibiting cellular tyrosinase activity, the protein expression of cellular tyrosinase and tyrosinase-related protein-2, as well as the mRNA expression of Paired box 3 and microphthalmia-associated transcription factor in a concentration-dependent manner. In the enzyme kinetic assay, the new compound 13 acted as an uncompetitive mixed-type inhibitor against the substrate l-3,4-dihydroxyphenylalanine and had a Km value against this substrate of 0.262 mM, as calculated using the Lineweaver–Burk plots. Taken together, our findings show compound 13 exhibits tyrosinase inhibition in human melanocytes and compound 13 may be a potential candidate for use in cosmetics. PMID:26633381

  11. Effects of Fumarprotocetraric Acid, a Depsidone from the Lichen Cladonia verticillaris, on Tyrosinase Activity

    Directory of Open Access Journals (Sweden)

    Luiz Fabrício Gardini Brandão

    2017-10-01

    Full Text Available Lichens are widely distributed around the world. Their phenolic compounds, consisting mainly of depsides and depsidones, have been extensively studied for important biological activities. More recently, these compounds have been evaluated for their inhibitory activity against enzymes such as tyrosinase, a key agent in melanin biosynthesis. In the present investigation, the depsidone fumarprotocetraric acid isolated from the lichen Cladonia verticillaris (Raddi Fr. was evaluated for its inhibitory activity against this critical enzyme. Kinetic study showed that depsidone at 0.6 mM inhibited tyrosinase activity by 39.8%. Lineweaver–Burk plots revealed that fumarprotocetraric acid can act as an uncompetitive or mixed-type inhibitor, depending on concentration. DOI: http://dx.doi.org/10.17807/orbital.v9i4.999 

  12. Sequence analysis of tyrosinase gene in ocular and oculocutaneous albinism patients: introducing three novel mutations.

    Science.gov (United States)

    Khordadpoor-Deilamani, Faravareh; Akbari, Mohammad Taghi; Karimipoor, Morteza; Javadi, Gholamreza

    2015-01-01

    Albinism is a heterogeneous genetic disorder of melanin synthesis that results in hypopigmented eyes (in patients with ocular albinism) or hair, skin, and eyes (in individuals with oculocutaneous albinism). It is associated with decreased visual acuity, nystagmus, strabismus, and photophobia. The tyrosinase gene is known to be involved in both oculocutaneous albinism and autosomal recessive ocular albinism. In this study, we aimed to screen the mutations in the TYR gene in the nonsyndromic OCA and autosomal recessive ocular albinism patients from Iran. The tyrosinase gene was examined in 23 unrelated patients with autosomal recessive ocular albinism or nonsyndromic OCA using DNA sequencing and bioinformatics analysis. TYR gene mutations were identified in 14 (app. 60%) albinism patients. We found 10 mutations, 3 of which were novel. No mutation was found in our ocular albinism patients, but one of them was heterozygous for the p.R402Q polymorphism.

  13. Substrate-bound tyrosinase electrode using gold nanoparticles anchored to pyrroloquinoline quinone for a pesticide biosensor

    Energy Technology Data Exchange (ETDEWEB)

    Kim, G.Y.; Kang, M.S.; Shim, J.; Moon, S.H. [Gwangju Inst. of Science and Technology (Korea, Republic of). Dept. of Environmental Science and Engineering

    2008-07-01

    Enzyme electrodes are now being considered for use in the detection of pesticides. However, the electrodes do not have the sensitivity to detect low concentration pesticides, and external substrates are needed to measure changes in enzyme activity. This study discussed a chemical species designed to mimic a substrate in the preparation of a tyrosinase (TYR) electrode for use without substrate standard solutions. Pyrroloquinolone quinone (PQQ) was integrated within the tyrosinase electrode and used as an assimilated substrate for measuring the pesticide. Gold (Au) nanoparticles were also used to detect low concentration pesticides. The TYR was immobilized on the PQQ-anchored Au nanoparticles by a covalent bond. The tethered PQQ was then reduced by obtaining 2-electrons from the electrode. The study showed that the substrate-bound enzyme electrode can be used to detect pesticide without a substrate standard solution through the immobilization of the enzyme and the substrate on the Au nanoparticles.

  14. Identification of geranic acid, a tyrosinase inhibitor in lemongrass (Cymbopogon citratus).

    Science.gov (United States)

    Masuda, Toshiya; Odaka, Yuka; Ogawa, Natsuko; Nakamoto, Katsuo; Kuninaga, Hideki

    2008-01-23

    Lemongrass is a popular Asian herb having a lemon-like flavor. Very recently, potent tyrosinase inhibitory activity has been found in lemongrass in addition to various biological activities reported in the literature. The aim of the present study is to identify the active compounds in the lemongrass. An assay-guided purification revealed that one of the active substances was geranic acid. Geranic acid has two stereoisomers, which are responsible for the trans and cis geometry on the conjugated double bond. Both isomers are present in the active ethyl acetate-soluble extract of the lemongrass, and their IC50 values were calculated to be 0.14 and 2.3 mM, respectively. The structure requirement of geranic acid for the potent tyrosinase inhibitory activity was investigated using geranic acid-related compounds.

  15. Inhibitory effects of constituents of Morinda citrifolia seeds on elastase and tyrosinase.

    Science.gov (United States)

    Masuda, Megumi; Murata, Kazuya; Fukuhama, Akiko; Naruto, Shunsuke; Fujita, Tadashi; Uwaya, Akemi; Isami, Fumiyuki; Matsuda, Hideaki

    2009-07-01

    A 50% ethanolic extract (MCS-ext) from seeds of Morinda citrifolia ("noni" seeds) showed more potent in vitro inhibition of elastase and tyrosinase, and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity than extracts of M. citrifolia leaves or flesh. Activity-guided fractionation of MCS-ext using in vitro assays led to the isolation of ursolic acid as an active constituent of elastase inhibitory activity. 3,3'-Bisdemethylpinoresinol, americanin A, and quercetin were isolated as active constituents having both tyrosinase inhibitory and radical scavenging activities. Americanin A and quercetin also showed superoxide dismutase (SOD)-like activity. These active compounds were isolated from noni seeds for the first time.

  16. A diterpenoid sugiol from Metasequoia glyptostroboides with α-glucosidase and tyrosinase inhibitory potential

    Directory of Open Access Journals (Sweden)

    Vivek K. Bajpai

    2014-08-01

    Full Text Available Nowadays use of plant derived natural compounds have become a topic of increasing interest in food and medicine industries due to their multitude of biological and therapeutic properties. In this study, a diterpenoid compound sugiol, isolated from Metasequoia glyptostroboides was evaluated for α–glucosidase and tyrosinase inhibitory efficacy in terms of its potent anti-diabetic and anti-melanogenesis potential, respectively. As a result, sugiol at the concentration range of (100-10,000 µg/mL and (20-500 µg/mL showed potent efficacy on inhibiting α-glucosidase and tyrosinase enzymes in vitro ranging from 12.34-63.47% and 28.22-67.43%, respectively. These findings confirm the therapeutic potential of diterpenoid compound sugiol from M. glyptostroboides as a novel candidate for using in food and medicine industry which may have practical potential to cure skin and diabetes mellitus type-2 related disorders.

  17. Inhibition on cholinesterase and tyrosinase by alkaloids and phenolics from Aristotelia chilensis leaves.

    Science.gov (United States)

    Cespedes, Carlos L; Balbontin, Cristian; Avila, Jose G; Dominguez, Mariana; Alarcon, Julio; Paz, Cristian; Burgos, Viviana; Ortiz, Leandro; Peñaloza-Castro, Ignacio; Seigler, David S; Kubo, Isao

    2017-11-01

    It is reported in this study the effect of isolates from leaves of Aristotelia chilensis as inhibitors of acetylcholinesterase (AChE), butyrylcholinesterase (BChE) and tyrosinase enzymes. The aim of the paper was to evaluate the activity of A. chilensis towards different enzymes. In addition to pure compounds, extracts rich in alkaloids and phenolics were tested. The most active F5 inhibited AChE (79.5% and 89.8% at 10.0 and 20.0 μg/mL) and against BChE (89.5% and 97.8% at 10.0 and 20.0 μg/mL), showing a strong mixed-type inhibition against AChE and BChE. F3 (a mixture of flavonoids and phenolics acids), showed IC 50 of 90.7 and 59.6 μg/mL of inhibitory activity against AChE and BChE, inhibiting the acetylcholinesterase competitively. Additionally, F3 showed and high potency as tyrosinase inhibitor with IC 50 at 8.4 μg/mL. Sample F4 (anthocyanidins and phenolic composition) presented a complex, mixed-type inhibition of tyrosinase with a IC 50 of 39.8 μg/mL. The findings in this investigation show that this natural resource has a strong potential for future research in the search of new phytotherapeutic treatments for cholinergic deterioration ailments avoiding the side effects of synthetic drugs. This is the first report as cholinesterases and tyrosinase inhibitors of alkaloids and phenolics from A. chilensis leaves. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. Catalytic oxidation of 2-aminophenols and ortho hydroxylation of aromatic amines by tyrosinase

    International Nuclear Information System (INIS)

    Toussaint, O.; Lerch, K.

    1987-01-01

    The usual substrates of tyrosinase, a copper-containing monooxygenase (EC 1.14.18.1), are monophenols and o-diphenols which are both converted to o-quinones. In this paper, the authors studied the reaction of this enzyme with two new classes of substrates: aromatic amines and o-aminophenols, structural analogues of monophenols and o-diphenols, respectively. They undergo the same catalytic reactions (ortho hydroxylation and oxidation), as documented by product analysis and kinetic studies. In the presence of tyrosinase, arylamines and o-aminophenols are converted to o-quinone imines, which are isolated as quinone anils or phenoxazones. As an example, in the presence of tyrosinase, 2-amino-3-hydroxybenzoic acid (an o-aminophenol) is converted to cinnabarinic acid, a well-known phenoxazone, while p-aminotoluene (an aromatic amine) gives rise to the formation of 5-amino-2-methyl-1,4-benzoquinone 1-(4-methylanil). Kinetic studies using an oxygen electrode show that arylamines and the corresponding monophenols exhibit similar Michaelis constants. In contrast, the reaction rates observed for aromatic amines are relatively slow as compared to monophenols. The enzymatic conversion of arylamines by tryosinase is different from the typical ones: N-oxidation and ring hydroxylation without further oxidation. This difference originates from the regiospecific hydroxylation (ortho position) and subsequent oxidation of the intermediate o-aminophenol to the corresponding o-quinone imine. Finally, the well-know monooxygenase activity of tyrosinase was also confirmed for the aromatic amine p-aminotoluene, with 18 O 2

  19. Evaluation of Cinnamomum osmophloeum Kanehira Extracts on Tyrosinase Suppressor, Wound Repair Promoter, and Antioxidant

    Directory of Open Access Journals (Sweden)

    Man-Gang Lee

    2015-01-01

    Full Text Available Cinnamomum osmophloeum Kanehira belongs to the Lauraceae family of Taiwan’s endemic plants. In this study, C. osmophloeum Kanehira extract has shown inhibition of tyrosinase activity on B16-F10 cellular system first. Whether extracts inhibited mushroom tyrosinase activity was tested, and a considerable inhibition of mushroom tyrosinase activity by in vitro assays was presented. Animal experiments of C. osmophloeum Kanehira were carried out by observing animal wound repair, and the extracts had greater wound healing power than the vehicle control group (petroleum jelly with 8% DMSO, w/v. In addition, the antioxidant capacity of C. osmophloeum Kanehira extracts in vitro was evaluated. We measured C. osmophloeum Kanehira extract’s free radical scavenging capability, metal chelating, and reduction power, such as biochemical activity analysis. The results showed that a high concentration of C. osmophloeum Kanehira extract had a significant scavenging capability of free radical, a minor effect of chelating ability, and moderate reducing power. Further exploration of the possible physiological mechanisms and the ingredient components of skincare product for skin-whitening, wound repair, or antioxidative agents are to be done.

  20. Detection of toxic compounds in real water samples using a conductometric tyrosinase biosensor

    International Nuclear Information System (INIS)

    Anh, Tuan Mai; Dzyadevych, Sergei V.; Prieur, Nicolas; Duc, Chien Nguyen; Pham, T.D.; Renault, Nicole Jaffrezic; Chovelon, Jean-Marc

    2006-01-01

    A conductometric tyrosinase biosensor for the detection of some toxic compounds including diuron, atrazine, and copper ions was developed. The work of this biosensor is based on the principle of change of conductivity of the enzyme membrane when tyrosinase either interacts with 4-chlorophenol substrate or is inhibited by pollutants. The different samples tested were solutions containing diuron, atrazine, copper, lead and zinc ions, mixtures of copper/atrazine or copper/diuron and real water samples coming from a Vietnamese river. In the last case, classical techniques such as GC-MS or atomic absorption spectrometry were used in order to estimate exact concentration of these species in real water samples. Results have shown that such a biosensor could be used as an early warning system for the detection of these pollutants, as no matrix effect coming from the real sample was observed and no synergetic or antagonist effects were found for the mixture of toxic compounds. In addition, results were coherent with the content of the tyrosinase inhibitors

  1. Detection of toxic compounds in real water samples using a conductometric tyrosinase biosensor

    Energy Technology Data Exchange (ETDEWEB)

    Anh, Tuan Mai [Laboratoire d' Application de la Chimie a l' Environnement, UMR CNRS 5634, Universite Claude Bernard Lyon I, 43 Boulevard du 11 Nov. 1918, 69622 Villeurbanne Cedex (France); International Training Institute for Materials Science (ITIMS), Hanoi University of Technology, 1 Dai Co Viet, Hanoi, Vietnam (Viet Nam); Dzyadevych, Sergei V. [Laboratory of Biomolecular Electronics, Institute of Molecular Biology and Genetics, National Academy of Sciences of Ukraine, 150 Zabolotnogo Str., Kiev 03143 (Ukraine); Prieur, Nicolas [Institute of Natural Products Chemistry, Vietnam National Centre for Science and Technology, Hoang Quoc Viet Str., Hanoi, Vietnam (Viet Nam); Duc, Chien Nguyen [International Training Institute for Materials Science (ITIMS), Hanoi University of Technology, 1 Dai Co Viet, Hanoi, Vietnam (Viet Nam); Pham, T.D. [International Training Institute for Materials Science (ITIMS), Hanoi University of Technology, 1 Dai Co Viet, Hanoi, Vietnam (Viet Nam); Renault, Nicole Jaffrezic [Ecole Centrale de Lyon, CEGELY, UMR CNRS 5005, 36 Avenue Guy de Collongue, 69134 Ecully Cedex (France); Chovelon, Jean-Marc [Laboratoire d' Application de la Chimie a l' Environnement, UMR CNRS 5634, Universite Claude Bernard Lyon I, 43 Boulevard du 11 Nov. 1918, 69622 Villeurbanne Cedex (France)]. E-mail: chovelon@univ-lyon1.fr

    2006-03-15

    A conductometric tyrosinase biosensor for the detection of some toxic compounds including diuron, atrazine, and copper ions was developed. The work of this biosensor is based on the principle of change of conductivity of the enzyme membrane when tyrosinase either interacts with 4-chlorophenol substrate or is inhibited by pollutants. The different samples tested were solutions containing diuron, atrazine, copper, lead and zinc ions, mixtures of copper/atrazine or copper/diuron and real water samples coming from a Vietnamese river. In the last case, classical techniques such as GC-MS or atomic absorption spectrometry were used in order to estimate exact concentration of these species in real water samples. Results have shown that such a biosensor could be used as an early warning system for the detection of these pollutants, as no matrix effect coming from the real sample was observed and no synergetic or antagonist effects were found for the mixture of toxic compounds. In addition, results were coherent with the content of the tyrosinase inhibitors.

  2. Antioxidant activity, acetylcholinesterase and tyrosinase inhibitory potential of Pulmonaria officinalis and Centarium umbellatum extracts

    Directory of Open Access Journals (Sweden)

    Elena Neagu

    2018-03-01

    Full Text Available In this study several investigations and tests were performed to determine the antioxidant activity and the acetylcholinesterase and tyrosinase inhibitory potential of Pulmonaria officinalis and Centarium umbellatum aqueous extracts (10% mass and ethanolic extracts (10% mass and 70% ethanol, respectively. Moreover, for each type of the prepared extracts of P. officinalis and of C. umbellatum the content in the biologically active compounds – polyphenols, flavones and proanthocyanidins was determined. The antioxidant activity was assessed using two methods, namely the 2,2-diphenyl-1-picrylhydrazyl (DPPH assay and reducing power assay. The analyzed plant extracts showed a high acetylcholinesterase and tyrosinase inhibitory activity in the range of 72.24–94.24% (at the highest used dose – 3 mg/mL, 66.96% and 94.03% (at 3 mg/mL, respectively correlated with a high DPPH radical inhibition – 70.29–84.9% (at 3 mg/mL. These medicinal plants could provide a potential natural source of bioactive compounds and could be beneficial to the human health, especially in the neurodegenerative disorders and as sources of natural antioxidants in food industry. Keywords: Acetylcholinesterase inhibitory activity, Tyrosinase inhibitory activity, Antioxidant activity, Pulmonaria officinalis and Centarium umbellatum

  3. A rational workflow for sequential virtual screening of chemical libraries on searching for new tyrosinase inhibitors.

    Science.gov (United States)

    Le-Thi-Thu, Huong; Casanola-Martín, Gerardo M; Marrero-Ponce, Yovani; Rescigno, Antonio; Abad, Concepcion; Khan, Mahmud Tareq Hassan

    2014-01-01

    The tyrosinase is a bifunctional, copper-containing enzyme widely distributed in the phylogenetic tree. This enzyme is involved in the production of melanin and some other pigments in humans, animals and plants, including skin pigmentations in mammals, and browning process in plants and vegetables. Therefore, enzyme inhibitors has been under the attention of the scientist community, due to its broad applications in food, cosmetic, agricultural and medicinal fields, to avoid the undesirable effects of abnormal melanin overproduction. However, the research of novel chemical with antityrosinase activity demands the use of more efficient tools to speed up the tyrosinase inhibitors discovery process. This chapter is focused in the different components of a predictive modeling workflow for the identification and prioritization of potential new compounds with activity against the tyrosinase enzyme. In this case, two structure chemical libraries Spectrum Collection and Drugbank are used in this attempt to combine different virtual screening data mining techniques, in a sequential manner helping to avoid the usually expensive and time consuming traditional methods. Some of the sequential steps summarize here comprise the use of drug-likeness filters, similarity searching, classification and potency QSAR multiclassifier systems, modeling molecular interactions systems, and similarity/diversity analysis. Finally, the methodologies showed here provide a rational workflow for virtual screening hit analysis and selection as a promissory drug discovery strategy for use in target identification phase.

  4. Tyrosinase, could it be a missing link in ochronosis in alkaptonuria?

    Science.gov (United States)

    Taylor, Adam M; Kammath, Vishnu; Bleakley, Aaron

    2016-06-01

    The hypothesis that is proposed is that tyrosinase, an enzyme widely found within the human body is implicated in the ochronosis that occurs in alkaptonuria; an autosomal recessive condition first used by Archibald Garrod to describe the theory of "Inborn Errors of Metabolism." The disease results from the absence of a single enzyme in the liver that breaks down homogentisic acid; this molecule becomes systemically elevated in sufferers. The condition is characterised by a clinical triad of symptoms; homogentisic aciduria from birth, ochronosis (darkening) of collagenous tissues (from ∼30years of age) and ochronotic osteoarthropathy in weight bearing joints due to long term ochronosis in them (from ∼40years of age). Tyrosinase, a polyphenol oxidase has been shown in many species to contribute to the darkening of tissues in many organisms; including humans in the production of melanin. Tyrosinase under the right conditions shows alterations in its substrate specificity and may contribute to the darkening seen in AKU where it moves away from polymerising tyrosine but also homogentisic acid, the causative molecule in alkaptonuria, that is present in excess. Copyright © 2016. Published by Elsevier Ltd.

  5. Tyrosinase Inhibitory and Antioxidant Activities of Silk Cocoons and Mulberry Leaves

    International Nuclear Information System (INIS)

    Thongphasuk, Jarunee; Thongphasuk, Piyanuch

    2005-10-01

    Silk cocoons and mulberry leaves have been used in the field of medicines, cosmetics, and foods. The objective of this study is to determine the antioxidant activities of silk cocoons and mulberry leaves using 1,1-diphenyl-2-picryl-hydrazyl radical and thin-layer chromatography (TLC), and to determine tyrosinase inhibitory activities using dihydroxyphenylalanine. The water and ethanol extracts from silk cocoons (Nang Noi, U B1, and Lao) and mulberry leaves showed antioxidants and tyrosinase inhibitory activities. However, the extracts from all samples at 1,000 μg/reaction mixture inhibited tyrosinase in the range of 12.28-45.98%, which was much lower than the standard whitening agent kojic acid (IC50 0.45 μg/reaction mixture). The results from TLC showed that the ethanol extracts from the 3 species of cocoons contained flavonoids, but only the extract from Nang Noi contained carotenoid. In addition, the separation destroyed the fraction with high antioxidant activity. Therefore, the disadvantage of the extract separation is increased cost and decreased antioxidant activities

  6. Catalytic oxidation of o-aminophenols and aromatic amines by mushroom tyrosinase.

    Science.gov (United States)

    Muñoz-Muñoz, Jose Luis; Garcia-Molina, Francisco; Garcia-Ruiz, Pedro Antonio; Varon, Ramon; Tudela, Jose; Rodriguez-Lopez, Jose N; Garcia-Canovas, Francisco

    2011-12-01

    The kinetics of tyrosinase acting on o-aminophenols and aromatic amines as substrates was studied. The catalytic constants of aromatic monoamines and o-diamines were both low, these results are consistent with our previous mechanism in which the slow step is the transfer of a proton by a hydroxyl to the peroxide in oxy-tyrosinase (Fenoll et al., Biochem. J. 380 (2004) 643-650). In the case of o-aminophenols, the hydroxyl group indirectly cooperates in the transfer of the proton and consequently the catalytic constants in the action of tyrosinase on these compounds are higher. In the case of aromatic monoamines, the Michaelis constants are of the same order of magnitude than for monophenols, which suggests that the monophenols bind better (higher binding constant) to the enzyme to facilitate the π-π interactions between the aromatic ring and a possible histidine of the active site. In the case of aromatic o-diamines, both the catalytic and Michaelis constants are low, the values of the catalytic constants being lower than those of the corresponding o-diphenols. The values of the Michaelis constants of the aromatic o-diamines are slightly lower than those of their corresponding o-diphenols, confirming that the aromatic o-diamines bind less well (lower binding constant) to the enzyme. Copyright © 2011 Elsevier B.V. All rights reserved.

  7. Tyrosinase Inhibitory and Antioxidant Activities of Silk Cocoons and Mulberry Leaves

    Energy Technology Data Exchange (ETDEWEB)

    Thongphasuk, Jarunee [Office of Atoms for Peace, Bangkok (Thailand); Thongphasuk, Piyanuch [Department of Pharmaceutical Chemistry, Faculty of Pharmacy, Rangsit University, Pathumthani (Thailand)

    2005-10-15

    Silk cocoons and mulberry leaves have been used in the field of medicines, cosmetics, and foods. The objective of this study is to determine the antioxidant activities of silk cocoons and mulberry leaves using 1,1-diphenyl-2-picryl-hydrazyl radical and thin-layer chromatography (TLC), and to determine tyrosinase inhibitory activities using dihydroxyphenylalanine. The water and ethanol extracts from silk cocoons (Nang Noi, U B1, and Lao) and mulberry leaves showed antioxidants and tyrosinase inhibitory activities. However, the extracts from all samples at 1,000 {mu}g/reaction mixture inhibited tyrosinase in the range of 12.28-45.98%, which was much lower than the standard whitening agent kojic acid (IC50 0.45 {mu}g/reaction mixture). The results from TLC showed that the ethanol extracts from the 3 species of cocoons contained flavonoids, but only the extract from Nang Noi contained carotenoid. In addition, the separation destroyed the fraction with high antioxidant activity. Therefore, the disadvantage of the extract separation is increased cost and decreased antioxidant activities.

  8. Stable isotopes

    International Nuclear Information System (INIS)

    Evans, D.K.

    1986-01-01

    Seventy-five percent of the world's stable isotope supply comes from one producer, Oak Ridge Nuclear Laboratory (ORNL) in the US. Canadian concern is that foreign needs will be met only after domestic needs, thus creating a shortage of stable isotopes in Canada. This article describes the present situation in Canada (availability and cost) of stable isotopes, the isotope enrichment techniques, and related research programs at Chalk River Nuclear Laboratories (CRNL)

  9. Hair Dyes Resorcinol and Lawsone Reduce Production of Melanin in Melanoma Cells by Tyrosinase Activity Inhibition and Decreasing Tyrosinase and Microphthalmia-Associated Transcription Factor (MITF Expression

    Directory of Open Access Journals (Sweden)

    Shu-Mei Lee

    2015-01-01

    Full Text Available Hair coloring products are one of the most important cosmetics for modern people; there are three major types of hair dyes, including the temporary, semi-permanent and permanent hair dyes. The selected hair dyes (such as ammonium persulfate, sodium persulfate, resorcinol and lawsone are the important components for hair coloring products. Therefore, we analyzed the effects of these compounds on melanogenesis in B16-F10 melanoma cells. The results proved that hair dyes resorcinol and lawsone can reduce the production of melanin. The results also confirmed that resorcinol and lawsone inhibit mushroom and cellular tyrosinase activities in vitro. Resorcinol and lawsone can also downregulate the protein levels of tyrosinase and microphthalmia-associated transcription factor (MITF in B16-F10 cells. Thus, we suggest that frequent use of hair dyes may have the risk of reducing natural melanin production in hair follicles. Moreover, resorcinol and lawsone may also be used as hypopigmenting agents to food, agricultural and cosmetic industry in the future.

  10. Anthocyanin contents in the seed coat of black soya bean and their anti-human tyrosinase activity and antioxidative activity.

    Science.gov (United States)

    Jhan, J-K; Chung, Y-C; Chen, G-H; Chang, C-H; Lu, Y-C; Hsu, C-K

    2016-06-01

    The seed coat of black soya bean (SCBS) contains high amount of anthocyanins and shows antioxidant and anti-mushroom tyrosinase activities. The objectives of this study were to analyse the anthocyanins in SCBS with different solvents and to find the relationship between anthocyanin profile with anti-human and anti-mushroom tyrosinase activities. SCBS was extracted with hot water, 50 and 80% ethanol, 50 and 80% acetone and 50 and 80% acidified acetone. Total phenol and total flavonoid contents in the extracts were determined. Anthocyanins in the extracts were analysed using HPLC and LC/MS/MS. A genetically engineered human tyrosinase was used to evaluate the anti-tyrosinase potential of the extracts from SCBS. 80% acetone extract from SCBS obtained the highest total phenol, total flavonoid and cyanidin-3-O-glucoside (C3G) contents among all the extracts, whereas the hot water extract showed the lowest antioxidant contents. Three anthocyanin compounds were found in all the extracts from SCBS, and the analysis of HPLC and LC/MS/MS indicated that they were C3G, delphinidin-3-O-glucoside (D3G) and peonidin-3-O-glucoside (P3G). The ratios of C3G (2.84 mg g(-1) ), D3G (0.34 mg g(-1) ) and P3G (0.35 mg g(-1) ) in 80% acidified acetone extract were 76.6, 9.1 and 9.3%, respectively. All the extracts from SCBS possessed anti-human tyrosinase activity. Moreover, a good correlation was found between the anti-human tyrosinase activities and C3G contents in the extracts. Antioxidants in SCBS also possess anti-human and anti-mushroom tyrosinase activities. © 2015 Society of Cosmetic Scientists and the Société Française de Cosmétologie.

  11. Extracts of Morus nigra L. Leaves Standardized in Chlorogenic Acid, Rutin and Isoquercitrin: Tyrosinase Inhibition and Cytotoxicity.

    Directory of Open Access Journals (Sweden)

    Marcela Medeiros de Freitas

    Full Text Available Melanogenesis is a process responsible for melanin production, which is stored in melanocytes containing tyrosinase. Inhibition of this enzyme is a target in the cosmetics industry, since it controls undesirable skin conditions such as hyperpigmentation due to the overproduction of melanin. Species of the Morus genus are known for the beneficial uses offered in different parts of its plants, including tyrosinase inhibition. Thus, this project aimed to study the inhibitory activity of tyrosinase by extracts from Morus nigra leaves as well as the characterization of its chromatographic profile and cytotoxicity in order to become a new therapeutic option from a natural source. M. nigra leaves were collected, pulverized, equally divided into five batches and the standardized extract was obtained by passive maceration. There was no significant difference between batches for total solids content, yield and moisture content, which shows good reproducibility of the extraction process. Tyrosinase enzymatic activity was determined for each batch, providing the percentage of enzyme inhibition and IC50 values obtained by constructing dose-response curves and compared to kojic acid, a well-known tyrosinase inhibitor. High inhibition of tyrosinase activity was observed (above 90% at 15.625 μg/mL. The obtained IC50 values ranged from 5.00 μg/mL ± 0.23 to 8.49 μg/mL ± 0.59 and were compared to kojic acid (3.37 μg/mL ± 0.65. High Performance Liquid Chromatography analysis revealed the presence of chlorogenic acid, rutin and, its major compound, isoquercitrin. The chromatographic method employed was validated according to ICH guidelines and the extract was standardized using these polyphenols as markers. Cytotoxicity, assessed by MTT assay, was not observed on murine melanomas, human keratinocytes and mouse fibroblasts in tyrosinase IC50 values. This study demonstrated the potential of M. nigra leaf extract as a promising whitening agent of natural source

  12. Experiment study of tyrosinase gene's expression in HEK293 cell by MR

    International Nuclear Information System (INIS)

    Yuan Jianpeng; Liang Biling; Zhong Jinglian; Xie Bangkun; Zhang Weidong; Zhang Lin

    2004-01-01

    Objective: To transfect the tyrosinase gene into HEK293 cell as a reporter gene, and to evaluate the tyrosinase gene's expression by using MRI based on the gene's property of synthesizing large amount of melanin, and to search a way for evaluating the results of gene expression by MR in vitro. Methods: The plasmid of pcDNA3tyr which carried the full-length cDNA of tyrosinase gene was transfected into HEK293 cell by lipofectin, and MR signals of expressed melanin was observed by scanning the transfected cells with MR sequences of T 1 WI, T 1 WI/SPIR, and T 2 WI. Fontana stain and electric microscopy were used to search for melanin granules in transfected cells, and RT-PCR method was used to search for cDNA of tyrosinase gene. Results: (1) Plasmids of pcDNA3tyr could be transfected into HEK293 cells and could synthesize a large amount of melanin in them. The synthetic melanin in 10 6 cells, which had been transfected with 5 μg, 10 μg, and 20 μg plasmids of pcDNA3tyr separately, were all sufficient to be detected by MR and appeared as high signal on MR T 1 WI, T 1 WI/SPIR, and T 2 WI sequences. The more the amounts of transfected plasmids, the higher the signal intensities of MR imaging. On the other hand, 6.25 x 10 4 cells with 20 μg-plasmid of pcDNA3tyr transfection could also be detected by MR; (2) The melanin granules could be found in HEK293 cells in Fontana stain; (3) The melanin granules and their front bodies could be found in intracytoplasm of HEK293 cell by electric microscopy. (4) The cDNA fragment of tyrosinase gene could be detected in transfected HEK293 cells by RT-PCR. Conclusion: The fact that MR could detect the synthetic melanin in HEK293 cells controlled by expression of exogenous gene demonstrated that medical imaging combined with molecular biology technology could evaluate the result of gene expression in vitro, and it also indicated that medical imaging could play an important role in the evaluation of gene therapy following the development

  13. Melanogenesis-Inducing Effect of Cirsimaritin through Increases in Microphthalmia-Associated Transcription Factor and Tyrosinase Expression

    Directory of Open Access Journals (Sweden)

    Hyo Jung Kim

    2015-04-01

    Full Text Available The melanin-inducing properties of cirsimaritin were investigated in murine B16F10 cells. Cirsimaritin is an active flavone with methoxy groups, which is isolated from the branches of Lithocarpus dealbatus. Tyrosinase activity and melanin content in murine B16F10 melanoma cells were increased by cirsimaritin in a dose-dependent manner. Western blot analysis revealed that tyrosinase, tyrosinase-related protein (TRP 1, TRP2 protein levels were enhanced after treatment with cirsimaritin for 48 h. Cirsimaritin also upregulated the expression of microphthalmia-associated transcription factor (MITF after 24 h of treatment. Furthermore, cirsimaritin induced phosphorylation of cyclic adenosine monophosphate (cAMP response element-binding protein (CREB in a dose-dependent manner after treatment for 15 min. The cirsimaritin-mediated increase of tyrosinase activity was significantly attenuated by H89, a cAMP-dependent protein kinase A inhibitor. These findings indicate that cirsimaritin stimulates melanogenesis in B16F10 cells by activation of CREB as well as upregulation of MITF and tyrosinase expression, which was activated by cAMP signaling. Finally, the melanogenic effect of cirsimaritin was confirmed in human epidermal melanocytes. These results support the putative application of cirsimaritin in ultraviolet photoprotection and hair coloration treatments.

  14. Plumbagin Suppresses α-MSH-Induced Melanogenesis in B16F10 Mouse Melanoma Cells by Inhibiting Tyrosinase Activity

    Directory of Open Access Journals (Sweden)

    Taek-In Oh

    2017-02-01

    Full Text Available Recent studies have shown that plumbagin has anti-inflammatory, anti-allergic, antibacterial, and anti-cancer activities; however, it has not yet been shown whether plumbagin suppresses alpha-melanocyte stimulating hormone (α-MSH-induced melanin synthesis to prevent hyperpigmentation. In this study, we demonstrated that plumbagin significantly suppresses α-MSH-stimulated melanin synthesis in B16F10 mouse melanoma cells. To understand the inhibitory mechanism of plumbagin on melanin synthesis, we performed cellular or cell-free tyrosinase activity assays and analyzed melanogenesis-related gene expression. We demonstrated that plumbagin directly suppresses tyrosinase activity independent of the transcriptional machinery associated with melanogenesis, which includes micropthalmia-associated transcription factor (MITF, tyrosinase (TYR, and tyrosinase-related protein 1 (TYRP1. We also investigated whether plumbagin was toxic to normal human keratinocytes (HaCaT and lens epithelial cells (B3 that may be injured by using skin-care cosmetics. Surprisingly, lower plumbagin concentrations (0.5–1 μM effectively inhibited melanin synthesis and tyrosinase activity but do not cause toxicity in keratinocytes, lens epithelial cells, and B16F10 mouse melanoma cells, suggesting that plumbagin is safe for dermal application. Taken together, these results suggest that the inhibitory effect of plumbagin to pigmentation may make it an acceptable and safe component for use in skin-care cosmetic formulations used for skin whitening.

  15. Mushroom Tyrosinase: A Model System to Combine Experimental Investigation of Enzyme-Catalyzed Reactions, Data Handling Using R, and Enzyme-Inhibitor Structural Studies

    Science.gov (United States)

    Nairn, Robert; Cresswell, Will; Nairn, Jacqueline

    2015-01-01

    The activity of mushroom tyrosinase can be measured by monitoring the conversion of phenolic compounds into quinone derivatives using spectrophotometry. This article describes a series of experiments which characterize the functional properties of tyrosinase, the analysis of the resulting data using R to determine the kinetic parameters, and the…

  16. Lineage-specific expansion and loss of tyrosinase genes across platyhelminths and their induction profiles in the carcinogenic oriental liver fluke, Clonorchis sinensis.

    Science.gov (United States)

    Kim, Seon-Hee; Bae, Young-An

    2017-09-01

    Tyrosinase provides an essential activity during egg production in diverse platyhelminths by mediating sclerotization of eggshells. In this study, we investigated the genomic and evolutionary features of tyrosinases in parasitic platyhelminths whose genomic information is available. A pair of paralogous tyrosinases was detected in most trematodes, whereas they were lost in cyclophyllidean cestodes. A pseudophyllidean cestode displaying egg biology similar to that of trematodes possessed an orthologous gene. Interestingly, one of the paralogous tyrosinases appeared to have been multiplied into three copies in Clonorchis sinensis and Opisthorchis viverrini. In addition, a fifth tyrosinase gene that was minimally transcribed through all developmental stages was further detected in these opisthorchiid genomes. Phylogenetic analyses demonstrated that the tyrosinase gene has undergone duplication at least three times in platyhelminths. The additional opisthorchiid gene arose from the first duplication. A paralogous copy generated from these gene duplications, except for the last one, seemed to be lost in the major neodermatans lineages. In C. sinensis, tyrosinase gene expressions were initiated following sexual maturation and the levels were significantly enhanced by the presence of O2 and bile. Taken together, our data suggest that tyrosinase has evolved lineage-specifically across platyhelminths related to its copy number and induction mechanism.

  17. Inhibitory Effects of Urginea maritima (L. Baker, Zhumeria majdae Rech. F. and Wendelbo and Physalis divaricata D. Don Ethanolic Extracts on Mushroom Tyrosinase

    Directory of Open Access Journals (Sweden)

    Foroogh Namjoyan, Alireza Jahangiri, Mohammad Ebrahim Azemi, Hamideh Mousavi

    2016-06-01

    Full Text Available Background: Tyrosinase is a key enzyme in melanin synthesis from tyrosine. To prevent or treat pigmentation disorders, tyrosinase inhibitors have been used increasingly for medicinal and cosmetic products. The aim of this study is to evaluate inhibitory effects of Urginea maritima (L. Baker, Zhumeria majdae Rech.f. & Wendelbo and Physalis divaricata D.Don on mushroom tyrosinase. Methods: The inhibitory activities of the hydroalcoholic extracts of plants against oxidation of L-DOPA (as a substrate by mushroom tyrosinase were investigated. The amount of formed DOPAchrome was determined at 475 nm as optical density. Results: The extracts showed anti-tyrosinase activity weaker than positive control (Kojic acid. The inhibitory activity of tested plants: U.maritima, Z.majdae and P.divaricata against mushroom tyrosinase were 38.61, 29.70 and 25.74 % at 1.67 mg/mL, respectively. Conclusion: The most tyrosinase inhibitory activity was seen for U.maritima. However more investigations on human tyrosinase, toxicological and clinical studies are needed to confirm its activity.

  18. Skin protective effect of guava leaves against UV-induced melanogenesis via inhibition of ORAI1 channel and tyrosinase activity.

    Science.gov (United States)

    Lee, Dong-Ung; Weon, Kwon Yeon; Nam, Da-Yeong; Nam, Joo Hyun; Kim, Woo Kyung

    2016-12-01

    Ultraviolet (UV) irradiation is a major environmental factor affecting photoageing, which is characterized by skin wrinkle formation and hyperpigmentation. Although many factors are involved in the photoageing process, UV irradiation is thought to play a major role in melanogenesis. Tyrosinase is the key enzyme in melanin synthesis; therefore, many whitening agents target tyrosinase through various mechanisms, such as direct interference of tyrosinase catalytic activity or inhibition of tyrosinase mRNA expression. Furthermore, the highly selective calcium channel ORAI1 has been shown to be associated with UV-induced melanogenesis. Thus, ORAI1 antagonists may have applications in the prevention of melanogenesis. Here, we aimed to identify the antimelanogenesis agents from methanolic extract of guava leaves (Psidium guajava) that can inhibit tyrosinase and ORAI1 channel. The n-butanol (47.47%±7.503% inhibition at 10 μg/mL) and hexane (57.88%±7.09% inhibition at 10 μg/mL) fractions were found to inhibit ORAI1 channel activity. In addition, both fractions showed effective tyrosinase inhibitory activity (68.3%±0.50% and 56.9%±1.53% inhibition, respectively). We also confirmed that the hexane fraction decreased the melanin content induced by UVB irradiation and the ET-1-induced melanogenesis in murine B16F10 melanoma cells. These results suggest that the leaves of P. guajava can be used to protect against direct and indirect UV-induced melanogenesis. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  19. A second tyrosinase-related protein, TRP-2, maps to and is mutated at the mouse slaty locus.

    OpenAIRE

    Jackson, I J; Chambers, D M; Tsukamoto, K; Copeland, N G; Gilbert, D J; Jenkins, N A; Hearing, V

    1992-01-01

    We have cloned and sequenced mouse cDNAs corresponding to a third member of a family of melanocyte-specific mRNAs, which encode tyrosinase and related proteins. This new member, tyrosinase-related protein-2 (TRP-2), has approximately 40% amino acid identity with the two other proteins in the family and has the same structural features including two copper binding sites, two cysteine-rich regions, a signal peptide and a transmembrane domain. We now show that one of the cysteine-rich regions in...

  20. Antibacterial, antioxidant and tyrosinase-inhibition activities of pomegranate fruit peel methanolic extract

    Science.gov (United States)

    2012-01-01

    Background This study evaluated, using in vitro assays, the antibacterial, antioxidant, and tyrosinase-inhibition activities of methanolic extracts from peels of seven commercially grown pomegranate cultivars. Methods Antibacterial activity was tested on Gram-positive (Bacillus subtilis and Staphylococcus aureus) and Gram-negative bacteria (Escherichia coli and Klebsiella pneumonia) using a microdilution method. Several potential antioxidant activities, including radical-scavenging ability (RSA), ferrous ion chelating (FIC) and ferric ion reducing antioxidant power (FRAP), were evaluated. Tyrosinase enzyme inhibition was investigated against monophenolase (tyrosine) and diphenolase (DOPA), with arbutin and kojic acid as positive controls. Furthermore, phenolic contents including total flavonoid content (TFC), gallotannin content (GTC) and total anthocyanin content (TAC) were determined using colourimetric methods. HPLC-ESI/MSn analysis of phenolic composition of methanolic extracts was also performed. Results Methanolic peel extracts showed strong broad-spectrum activity against Gram-positive and Gram-negative bacteria, with the minimum inhibitory concentrations (MIC) ranging from 0.2 to 0.78 mg/ml. At the highest concentration tested (1000 μg/ml), radical scavenging activities were significantly higher in Arakta (83.54%), Ganesh (83.56%), and Ruby (83.34%) cultivars (P50%) against monophenolase and diphenolase activities at the highest screening concentration. The most active peel extract was the Bhagwa cultivar against monophenolase and the Arakta cultivar against diphenolase with IC50 values of 3.66 μg/ml and 15.88 μg/ml, respectively. High amounts of phenolic compounds were found in peel extracts with the highest and lowest total phenolic contents of 295.5 (Ganesh) and 179.3 mg/g dry extract (Molla de Elche), respectively. Catechin, epicatechin, ellagic acid and gallic acid were found in all cultivars, of which ellagic acid was the most abundant comprising

  1. Unpredictably Stable

    DEFF Research Database (Denmark)

    Failla, Virgilio; Melillo, Francesca; Reichstein, Toke

    2014-01-01

    Is entrepreneurship a more stable career choice for high employment turnover individuals? We find that a transition to entrepreneurship induces a shift towards stayer behavior and identify job matching, job satisfaction and lock-in effects as main drivers. These findings have major implications...

  2. Tyrosinase inhibition due to interaction of homocyst(e)ine with copper: the mechanism for reversible hypopigmentation in homocystinuria due to cystathionine beta-synthase deficiency.

    Science.gov (United States)

    Reish, O; Townsend, D; Berry, S A; Tsai, M Y; King, R A

    1995-01-01

    Deficiency of cystathionine beta-synthase (CBS) is a genetic disorder of transsulfuration resulting in elevated plasma homocyst(e)ine and methionine and decreased cysteine. Affected patients have multisystem involvement, which may include light skin and hair. Reversible hypopigmentation in treated homocystinuric patients has been infrequently reported, and the mechanism is undefined. Two CBS-deficient homocystinuric patients manifested darkening of their hypopigmented hair following treatment that decreased plasma homocyst(e)ine. We hypothesized that homocyst(e)ine inhibits tyrosinase, the major pigment enzyme. The activity of tyrosinase extracted from pigmented human melanoma cells (MNT-1) that were grown in the presence of homocysteine was reduced in comparison to that extracted from cells grown without homocysteine. Copper sulfate restored homocyst(e)ine-inhibited tyrosinase activity when added to the culture cell media at a proportion of 1.25 mol of copper sulfate per 1 mol of DL-homocysteine. Holo-tyrosinase activity was inhibited by adding DL-homocysteine to the assay reaction mixture, and the addition of copper sulfate to the reaction mixture prevented this inhibition. Other tested compounds, L-cystine and betaine did not affect tyrosinase activity. Our data suggest that reversible hypopigmentation in homocystinuria is the result of tyrosinase inhibition by homocyst(e)ine and that the probable mechanism of this inhibition is the interaction of homocyst(e)ine with copper at the active site of tyrosinase. Images Figure 1 PMID:7611281

  3. Isolation of tyrosinase inhibitors from Artocarpus heterophyllus and use of its extract as antibrowning agent.

    Science.gov (United States)

    Zheng, Zong-Ping; Cheng, Ka-Wing; To, James Tsz-Kin; Li, Haitao; Wang, Mingfu

    2008-12-01

    A new furanoflavone, 7-(2,4-dihydroxyphenyl)-4-hydroxy-2-(2-hydroxy propan-2-yl)-2, 3-dihydrofuro(3, 2-g)chromen-5-one (artocarpfuranol, 1), together with 14 known compounds, dihydromorin (2), steppogenin (3), norartocarpetin (4), artocarpanone (5), artocarpesin (6), artocarpin (7), cycloartocarpin (8), cycloartocarpesin (9), artocarpetin (10), brosimone I (11), cudraflavone B (12), carpachromene (13), isoartocarpesin (14), and cyanomaclurin (15) were isolated from the wood of Artocarpus heterophyllus. Their structures were identified by interpretation of MS,( 1)H-NMR,( 13)C-NMR, HMQC, and HMBC spectroscopic data. Among them, compounds 1-6 and 14 showed strong mushroom tyrosinase inhibitory activity with IC(50) values lower than 50 microM, more potent than kojic acid (IC(50) = 71.6 microM), a well-known tyrosinase inhibitor. In addition, extract of A. heterophyllus was evaluated for its antibrowning effect on fresh-cut apple slices. It was discovered that fresh-cut apple slices treated by dipping in solution of 0.03 or 0.05% of A. heterophyllus extract with 0.5% ascorbic acid did not undergo any substantial browning reaction after storage at room temperature for 24 h. The antibrowning effect was significantly better than samples treated with the extract (0.03 or 0.05%) or ascorbic acid (0.5%) alone. The results provide preliminary evidence supporting the potential of this natural extract as antibrowning agent in food systems.

  4. Phenols removal by immobilized tyrosinase reactor in on-line high performance liquid chromatography

    Energy Technology Data Exchange (ETDEWEB)

    Girelli, Anna Maria [Dipartimento di Chimica, Universita degli Studi di Roma ' La Sapienza' , P.le Aldo Moro 5, 00185 Rome (Italy)]. E-mail: annamaria.girelli@uniroma1.it; Mattei, Enrico [Dipartimento di Chimica, Universita degli Studi di Roma ' La Sapienza' , P.le Aldo Moro 5, 00185 Rome (Italy); Messina, Antonella [Dipartimento di Chimica, Universita degli Studi di Roma ' La Sapienza' , P.le Aldo Moro 5, 00185 Rome (Italy)

    2006-11-24

    The development of an immobilized enzyme reactor (IMER) based on tyrosinase immobilized on aminopropyl-controlled pore glass (AP-CPG) for the removal of phenols from model aqueous solutions was reported. To elucidate the influence of the substrate nature, the apparent (V{sup '}{sub max}, K{sup '}{sub m}) and the inherent (V{sub max}, K{sub m}) Michaelis-Menten constants were determined by Lineweaver-Burk method and the external diffusional contributions on measured enzyme activities were removed by a graphical method. The dephenolization process was realized by recycling the phenol solutions through the bioreactor connected to a chitosan trap in order to remove the colored quinone-type products of the tyrosinase reactions. The results indicated that a complete removal of phenol derivatives in the range of 150-300min, with the exception of 60% removal for phenol reached in 400min, was obtained. The observed sequence: cresol>4-methylcathecol>catechol>4-Cl-phenol-bar phenol was in accordance to the V{sup '}{sub max}/K{sup '}{sub m} values.

  5. A novel tyrosinase biosensor based on hydroxyapatite-chitosan nanocomposite for the detection of phenolic compounds

    International Nuclear Information System (INIS)

    Lu Limin; Zhang Li; Zhang Xiaobing; Huan Shuangyan; Shen Guoli; Yu Ruqin

    2010-01-01

    A novel tyrosinase biosensor based on hydroxyapatite nanoparticles (nano-HA)-chitosan nanocomposite has been developed for the detection of phenolic compounds. The uniform and size controlled nano-HA was synthesized by hydrothermal method, and its morphological characterization was examined by transmission electron microscope (TEM). Tyrosinase was then immobilized on a nano-HA-chitosan nanocomposite-modified gold electrode. Electrochemical impedance spectroscopy and cyclic voltammetry were used to characterize the sensing film. The prepared biosensor was applied to determine phenolic compounds by monitoring the reduction signal of the biocatalytically produced quinone species at -0.2 V (vs. saturated calomel electrode). The effects of the pH, temperature and applied potential on the biosensor performance were investigated, and experimental conditions were optimized. The biosensor exhibited a linear response to catechol over a wide concentration range from 10 nM to 7 μM, with a high sensitivity of 2.11 x 10 3 μA mM -1 cm -2 , and a limit of detection down to 5 nM (based on S/N = 3). The apparent Michaelis-Menten constants of the enzyme electrode were estimated to be 3.16, 1.31 and 3.52 μM for catechol, phenol and m-cresol, respectively. Moreover, the stability and reproducibility of this biosensor were evaluated with satisfactory results.

  6. α-Glucosidase and tyrosinase inhibitory effects of an abietane type diterpenoid taxoquinone from Metasequoia glyptostroboides.

    Science.gov (United States)

    Bajpai, Vivek K; Park, Yong-Ha; Na, MinKyun; Kang, Sun Chul

    2015-03-26

    Nowadays plant derived natural compounds have gained huge amount of research attention especially in food and medicine industries due to their multitude of biological and therapeutic properties as alternative medicines. In this study, a diterpenoid compound taxoquinone, isolated from Metasequoia glyptostroboides was evaluated for its α-glucosidase and tyrosinase inhibitory efficacy in terms of its potent anti-diabetic and depigmentation potential, respectively. As a result, taxoquinone at the concentration range of 100-3,000 μg/mL and 200-1,000 μg/mL showed potent efficacy on inhibiting α-glucosidase and tyrosinase enzymes by 9.24-51.32% and 11.14-52.32%, respectively. The findings of this study clearly evident potent therapeutic efficacy of an abietane diterpenoid taxoquinone isolated from M. glyptostroboides with a possibility for using it as a novel candidate in food and medicine industry as a natural alternative medicine to prevent diabetes mellitus type-2 related disorders and as a depigmentation agent.

  7. In vivo tyrosinase mini-gene transfer enhances killing effect of BNCT on amelanotic melanoma

    International Nuclear Information System (INIS)

    Kondoh, H.; Mishima, Y.; Hiratsuka, J.; Iwakura, M.

    2000-01-01

    Using accentuated melanogenesis principally occurring within melanoma cells, we have successfully treated human malignant melanoma (Mm) with 10 B-BPA BNCT. Despite this success, there are still remaining issues for poorly melanogenic Mm and further non-pigment cell tumors. We found the selective accumulation of 10 B-BPA to Mm is primarily due to the complex formation of BPA and melanin-monomers activity synthesized within Mm cells. Then, we succeeded in transferring the tyrosinase gene into amelanotic to substantially produce melanin monomers. These cells has demonstrated increased boron accumulation and enhanced killing effect of BNCT. Further, transfection of TRP-2 (DOPAchrome tautomerase) gene into poorly eumelanotic and slightly phenomelanotic Mm cells in culture cell systems also led to increased BPA accumulation. Thereafter, we studied in vivo gene transfer. We transferred the tyrosinase mini-gene by intra-tumor injection into poorly melanotic Mm proliferating subcutaneously in hamster skin, and performed BNCT. Compared to control tumors, gene-transferred tumors showed increased BPA accumulation leading to enhanced killing effect. (author)

  8. Antioxidant, Anti-Tyrosinase and Anti-Inflammatory Activities of Oil Production Residues from Camellia tenuifloria

    Directory of Open Access Journals (Sweden)

    Shu-Yuan Chiou

    2015-12-01

    Full Text Available Camellia tenuifloria is an indigenous Camellia species used for the production of camellia oil in Taiwan. This study investigated for the first time the potential antioxidant, anti-tyrosinase and anti-inflammatory activities of oil production byproducts, specifically those of the fruit shell, seed shell, and seed pomace from C. tenuifloria. It was found that the crude ethanol extract of the seed shell had the strongest DPPH scavenging and mushroom tyrosinase inhibitory activities, followed by the fruit shell, while seed pomace was the weakest. The IC50 values of crude extracts and fractions on monophenolase were smaller than diphenolase. The phenolic-rich methanol fraction of seed shell (SM reduced nitric oxide (NO production, and inducible nitric oxide synthase (iNOS expression in lipopolysaccharide (LPS-stimulated RAW 264.7 cells. It also repressed the expression of IL-1β, and secretion of prostaglandin E2 (PGE2 and IL-6 in response to LPS. SM strongly stimulated heme oxygenase 1 (HO-1 expression and addition of zinc protoporphyrin (ZnPP, a HO-1 competitive inhibitor, reversed the inhibition of NO production, indicating the involvement of HO-1 in its anti-inflammatory activity. The effects observed in this study provide evidence for the reuse of residues from C. tenuifloria in the food additive, medicine and cosmetic industries.

  9. Tyrosinase inhibitors from Calceolaria integrifolia s.l.: Calceolaria talcana aerial parts.

    Science.gov (United States)

    Muñoz, Evelyn; Avila, Jose G; Alarcón, Julio; Kubo, Isao; Werner, Enrique; Céspedes, Carlos L

    2013-05-08

    As a defense mechanism of the aerial parts of Calceolaria talcana (Calceolariaceae; formerly Scrophulariaceae) against herbivore offenses and insect pest attack, diterpenoids, triterpenoids, phenylethanoids, flavonoids, and iridoids are rapidly accumulated along the aerial parts, resulting in a unique natural biopesticide complex from this plant. In addition to verbascoside a series of known compounds were screened for their inhibitory activity against mushroom tyrosinase and protease enzymes. Ethyl acetate and n-hexane extracts, together with cyclopropyl-7,15-ent-pimaradiene (1), abietatriene (2), ursolic acid (3), α-lupeol (4), β-sitosterol (5), 2-hydroxy-3-(1,1-dimethylallyl)-1,4-naphthoquinone (6), α-dunnione (7), verbascoside (8), martynoside (9), and some known model compounds proved to be inhibitors of oxidation of L-3,4-dihydroxyphenylalanine (L-DOPA) catalyzed by tyrosinase (EC 1.14.18.1) with an IC50 between 10.0 and 200 ppm or μM, respectively, suggesting that phenolic moieties in the molecules assayed are important for the activity.

  10. Syndecan-2 regulates melanin synthesis via protein kinase C βII-mediated tyrosinase activation.

    Science.gov (United States)

    Jung, Hyejung; Chung, Heesung; Chang, Sung Eun; Choi, Sora; Han, Inn-Oc; Kang, Duk-Hee; Oh, Eok-Soo

    2014-05-01

    Syndecan-2, a transmembrane heparan sulfate proteoglycan that is highly expressed in melanoma cells, regulates melanoma cell functions (e.g. migration). Since melanoma is a malignant tumor of melanocytes, which largely function to synthesize melanin, we investigated the possible involvement of syndecan-2 in melanogenesis. Syndecan-2 expression was increased in human skin melanoma tissues compared with normal skin. In both mouse and human melanoma cells, siRNA-mediated knockdown of syndecan-2 was associated with reduced melanin synthesis, whereas overexpression of syndecan-2 increased melanin synthesis. Similar effects were also detected in human primary epidermal melanocytes. Syndecan-2 expression did not affect the expression of tyrosinase, a key enzyme in melanin synthesis, but instead enhanced the enzymatic activity of tyrosinase by increasing the membrane and melanosome localization of its regulator, protein kinase CβII. Furthermore, UVB caused increased syndecan-2 expression, and this up-regulation of syndecan-2 was required for UVB-induced melanin synthesis. Taken together, these data suggest that syndecan-2 regulates melanin synthesis and could be a potential therapeutic target for treating melanin-associated diseases. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  11. In vivo tyrosinase mini-gene transfer enhances killing effect of BNCT on amelanotic melanoma

    Energy Technology Data Exchange (ETDEWEB)

    Kondoh, H.; Mishima, Y. [Mishima Institute for Dermatological Research, Kobe, Hyogo (Japan); Hiratsuka, J. [Kawasaki Medical School, Dept. of Radiation Oncology, Kurashiki, Okayama (Japan); Iwakura, M. [Kobe Univ. (Japan). School of Medicine

    2000-10-01

    Using accentuated melanogenesis principally occurring within melanoma cells, we have successfully treated human malignant melanoma (Mm) with {sup 10}B-BPA BNCT. Despite this success, there are still remaining issues for poorly melanogenic Mm and further non-pigment cell tumors. We found the selective accumulation of {sup 10}B-BPA to Mm is primarily due to the complex formation of BPA and melanin-monomers activity synthesized within Mm cells. Then, we succeeded in transferring the tyrosinase gene into amelanotic to substantially produce melanin monomers. These cells has demonstrated increased boron accumulation and enhanced killing effect of BNCT. Further, transfection of TRP-2 (DOPAchrome tautomerase) gene into poorly eumelanotic and slightly phenomelanotic Mm cells in culture cell systems also led to increased BPA accumulation. Thereafter, we studied in vivo gene transfer. We transferred the tyrosinase mini-gene by intra-tumor injection into poorly melanotic Mm proliferating subcutaneously in hamster skin, and performed BNCT. Compared to control tumors, gene-transferred tumors showed increased BPA accumulation leading to enhanced killing effect. (author)

  12. Phenols removal by immobilized tyrosinase reactor in on-line high performance liquid chromatography

    International Nuclear Information System (INIS)

    Girelli, Anna Maria; Mattei, Enrico; Messina, Antonella

    2006-01-01

    The development of an immobilized enzyme reactor (IMER) based on tyrosinase immobilized on aminopropyl-controlled pore glass (AP-CPG) for the removal of phenols from model aqueous solutions was reported. To elucidate the influence of the substrate nature, the apparent (V ' max , K ' m ) and the inherent (V max , K m ) Michaelis-Menten constants were determined by Lineweaver-Burk method and the external diffusional contributions on measured enzyme activities were removed by a graphical method. The dephenolization process was realized by recycling the phenol solutions through the bioreactor connected to a chitosan trap in order to remove the colored quinone-type products of the tyrosinase reactions. The results indicated that a complete removal of phenol derivatives in the range of 150-300min, with the exception of 60% removal for phenol reached in 400min, was obtained. The observed sequence: cresol>4-methylcathecol>catechol>4-Cl-phenol-bar phenol was in accordance to the V ' max /K ' m values

  13. Stable particles

    International Nuclear Information System (INIS)

    Samios, N.P.

    1993-01-01

    I have been asked to review the subject of stable particles, essentially the particles that eventually comprised the meson and baryon octets. with a few more additions -- with an emphasis on the contributions made by experiments utilizing the bubble chamber technique. In this activity, much work had been done by the photographic emulsion technique and cloud chambers-exposed to cosmic rays as well as accelerator based beams. In fact, many if not most of the stable particles were found by these latter two techniques, however, the forte of the bubble chamber (coupled with the newer and more powerful accelerators) was to verify, and reinforce with large statistics, the existence of these states, to find some of the more difficult ones, mainly neutrals and further to elucidate their properties, i.e., spin, parity, lifetimes, decay parameters, etc

  14. Development and application of a tyrosinase-based time-temperature indicator (TTI) for determining the quality of turbot sashimi

    Science.gov (United States)

    Xu, Fengjuan; Ge, Lei; Li, Zhenxing; Lin, Hong; Mao, Xiangzhao

    2017-10-01

    Time-temperature indicators (TTIs) are convenient intuitive devices that are widely used to predict food quality. The aim of this study is to develop a new simple device which can be attached to food packages as a quality indicator for turbot sashimi. In this study, a solid TTI based on the reaction between tyrosinase and tyrosine was developed. The Arrhenius behavior of this enzymatic TTI was studied. The kinetics of the tyrosinase-based TTI was investigated in the form of color change from colorless to dark black induced by the enzymatic reaction. The mathematical formula for the color alterations as a function of time and temperature was established. The longest indication time for the developed TTI was 50 hours at 4°C. The activation energy of the tyrosinase-based TTI was 0.409 kJ mol-1. The suitability of the tyrosinase-based TTI was validated for turbot sashimi using total plate count. The feasibility of using this TTI as a quality indicator for turbot sashimi was assessed based on the activation energy and indication time. Therefore, the tyrosinasebased TTI system developed in this study could be used as an effective tool for monitoring the quality changes of turbot sashimi during the distribution and storage.

  15. Interaction between G Protein-Coupled Receptor 143 and Tyrosinase: Implications for Understanding Ocular Albinism Type 1.

    Science.gov (United States)

    De Filippo, Elisabetta; Schiedel, Anke C; Manga, Prashiela

    2017-02-01

    Developmental eye defects in X-linked ocular albinism type 1 are caused by G-protein coupled receptor 143 (GPR143) mutations. Mutations result in dysfunctional melanosome biogenesis and macromelanosome formation in pigment cells, including melanocytes and retinal pigment epithelium. GPR143, primarily expressed in pigment cells, localizes exclusively to endolysosomal and melanosomal membranes unlike most G protein-coupled receptors, which localize to the plasma membrane. There is some debate regarding GPR143 function and elucidating the role of this receptor may be instrumental for understanding neurogenesis during eye development and for devising therapies for ocular albinism type I. Many G protein-coupled receptors require association with other proteins to function. These G protein-coupled receptor-interacting proteins also facilitate fine-tuning of receptor activity and tissue specificity. We therefore investigated potential GPR143 interaction partners, with a focus on the melanogenic enzyme tyrosinase. GPR143 coimmunoprecipitated with tyrosinase, while confocal microscopy demonstrated colocalization of the proteins. Furthermore, tyrosinase localized to the plasma membrane when coexpressed with a GPR143 trafficking mutant. The physical interaction between the proteins was confirmed using fluorescence resonance energy transfer. This interaction may be required in order for GPR143 to function as a monitor of melanosome maturation. Identifying tyrosinase as a potential GPR143 binding protein opens new avenues for investigating the mechanisms that regulate pigmentation and neurogenesis. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

  16. Identification of tyrosinase specific inhibitors from Xanthium strumarium fruit extract using ultrafiltration-high performance liquid chromatography.

    Science.gov (United States)

    Wang, Zhiqiang; Hwang, Seung Hwan; Huang, Bo; Lim, Soon Sung

    2015-10-01

    In this study, a strategy based on ultrafiltration-high performance liquid chromatography coupled with diode array detection (UF-HPLC-DAD) was proposed for screening tyrosinase specific inhibitors in Xanthii fructus. The false negatives were distinguished by optimizing the UF-HPLC-DAD parameters to reduce the background noise; the false positives were distinguished by introducing a blocked tyrosinase in the control group for comparison. To obtain the best blocker, the competitive experiments were performed using various known ligands. Using this strategy, three competitive inhibitors (protocatechuic acid; 3,5-di-O-caffeoylquinic acid; and 1,5-di-O-caffeoylquinic acid) and one mixed-type inhibitor (chlorogenic acid) were identified. These results were verified using tyrosinase inhibition assay, kinetic analysis, and structural simulation of the complex. Our experimental results suggest that the proposed strategy could be useful for high-throughput identification of tyrosinase specific inhibitors in natural products. Copyright © 2015 Elsevier B.V. All rights reserved.

  17. The anti-browning agent sulfite inactivates Agaricus bisporus tyrosinase through covalent modification of the copper-B site

    NARCIS (Netherlands)

    Kuijpers, T.F.M.; Gruppen, H.; Sforza, S.; Berkel, van W.J.H.; Vincken, J.P.

    2013-01-01

    Sulfite salts are widely used as antibrowning agents in food processing. Nevertheless, the exact mechanism by which sulfite prevents enzymatic browning has remained unknown. Here, we show that sodium hydrogen sulfite (NaHSO3 ) irreversibly blocks the active site of tyrosinase from the edible

  18. OCA1 in different ethnic groups of india is primarily due to founder mutations in the tyrosinase gene.

    NARCIS (Netherlands)

    Chaki, M.; Sengupta, M.S.; Mukhopadhyay, A.; Subba Rao, I.; Majumder, P.P.; Das, M.; Samanta, S.; Ray, K.

    2006-01-01

    Oculocutaneous albinism (OCA) is a heterogeneous group of autosomal recessive disorders characterized by an abnormally low amount of melanin in the eyes, skin and hair, and associated with common developmental abnormalities of the eye. Defects in the tyrosinase gene (TYR) cause a common type of OCA,

  19. The integration of cyanide hydratase and tyrosinase catalysts enables effective degradation of cyanide and phenol in coking wastewaters

    Czech Academy of Sciences Publication Activity Database

    Martínková, Ludmila; Chmátal, Martin

    2016-01-01

    Roč. 102, October (2016), s. 90-95 ISSN 0043-1354 R&D Projects: GA TA ČR TA01021368; GA TA ČR(CZ) TA04021212; GA MŠk(CZ) LD12049 Institutional support: RVO:61388971 Keywords : Cyanide hydratase * Tyrosinase * Cyanide Subject RIV: CE - Biochemistry Impact factor: 6.942, year: 2016

  20. TYROSINASE-BASED CARBON PASTE ELECTRODE BIOSENSOR FOR DETECTION OF PHENOLS: BINDER AND PRE-OXIDATION EFFECTS

    Science.gov (United States)

    Tyrosinase-based carbon paste electrodes are evaluated with respect to the viscosity and polarity of the binder liquids. The electrodes constructed using a lower viscosity mineral oil or paraffin wax oil yielded a greater response to phenol and catechol than those using the hi...

  1. Singlet oxygen generation during the oxidation of L-tyrosine and L-dopa with mushroom tyrosinase

    Energy Technology Data Exchange (ETDEWEB)

    Miyaji, Akimitsu [Department of Environmental Chemistry and Engineering, Tokyo Institute of Technology, 4259-G1-14, Nagatsuta-cho, Midori-ku, Yokohama 226-8502 (Japan); Kohno, Masahiro [Department of Bioscience and Biotechnology, Tokyo Institute of Technology, 4259-G1-25 Nagatsuta-cho, Midori-ku, Yokohama 226-8502 (Japan); Inoue, Yoshihiro [Showa Pharmaceutical University, 3-3165 Higashi-tamagawagakuen, Machida, Tokyo 194-8543 (Japan); Baba, Toshihide, E-mail: tbaba@chemenv.titech.ac.jp [Department of Environmental Chemistry and Engineering, Tokyo Institute of Technology, 4259-G1-14, Nagatsuta-cho, Midori-ku, Yokohama 226-8502 (Japan)

    2016-03-18

    The generation of singlet oxygen during the oxidation of tyrosine and L-dopa using mushroom tyrosinase in a phosphate buffer (pH 7.4), the model of melanin synthesis in melanocytes, was examined. The reaction was performed in the presence of 2,2,6,6-tetramethyl-4-piperidone (4-oxo-TEMP), an acceptor of singlet oxygen and the electron spin resonance (ESR) of the spin adduct, 4-oxo-2,2,6,6-tetramethyl-1-piperidinyloxy (4-oxo-TEMPO), was measured. An increase in the ESR signal attributable to 4-oxo-TEMPO was observed during the oxidation of tyrosine and L-dopa with tyrosinase, indicating the generation of singlet oxygen. The results suggest that {sup 1}O{sub 2} generation via tyrosinase-catalyzed melanin synthesis occurs in melanocyte. - Highlights: • Generation of singlet oxygen was observed during tyrosinase-catalyzed tyrosine oxidation. • The singlet oxygen generated when tyrosine was converted into dopachrome. • The amount of singlet oxygen is not sufficient for cell toxicity. • It decreased when the hydroxyl radicals and/or superoxide anions were trapped.

  2. Stable isotopes

    International Nuclear Information System (INIS)

    Brazier, J.L.; Guinamant, J.L.

    1995-01-01

    According to the progress which has been realised in the technology of separating and measuring isotopes, the stable isotopes are used as preferable 'labelling elements' for big number of applications. The isotopic composition of natural products shows significant variations as a result of different reasons like the climate, the seasons, or their geographic origins. So, it was proved that the same product has a different isotopic composition of alimentary and agriculture products. It is also important in detecting the pharmacological and medical chemicals. This review article deals with the technology, like chromatography and spectrophotometry, adapted to this aim, and some important applications. 17 refs. 6 figs

  3. Stable Tetraquarks

    Energy Technology Data Exchange (ETDEWEB)

    Quigg, Chris [Fermilab

    2018-04-13

    For very heavy quarks, relations derived from heavy-quark symmetry imply novel narrow doubly heavy tetraquark states containing two heavy quarks and two light antiquarks. We predict that double-beauty states will be stable against strong decays, whereas the double-charm states and mixed beauty+charm states will dissociate into pairs of heavy-light mesons. Observing a new double-beauty state through its weak decays would establish the existence of tetraquarks and illuminate the role of heavy color-antitriplet diquarks as hadron constituents.

  4. Stable beams

    CERN Multimedia

    2015-01-01

    Stable beams: two simple words that carry so much meaning at CERN. When LHC page one switched from "squeeze" to "stable beams" at 10.40 a.m. on Wednesday, 3 June, it triggered scenes of jubilation in control rooms around the CERN sites, as the LHC experiments started to record physics data for the first time in 27 months. This is what CERN is here for, and it’s great to be back in business after such a long period of preparation for the next stage in the LHC adventure.   I’ve said it before, but I’ll say it again. This was a great achievement, and testimony to the hard and dedicated work of so many people in the global CERN community. I could start to list the teams that have contributed, but that would be a mistake. Instead, I’d simply like to say that an achievement as impressive as running the LHC – a machine of superlatives in every respect – takes the combined effort and enthusiasm of everyone ...

  5. Anti–elastase, anti–tyrosinase and matrix metalloproteinase–1 inhibitory activity of earthworm extracts as potential new anti–aging agent

    Directory of Open Access Journals (Sweden)

    Nurhazirah Azmi

    2014-05-01

    Conclusions: Earthworms extract showed effective inhibition of tyrosinase, elastase and MMP-1 activities. Therefore, this experiment further rationalizes the traditional use of this worm extracts which may be useful as an anti-wrinkle agent.

  6. Biosensor based on a glassy carbon electrode modified with tyrosinase immobilized on multiwalled carbon nanotubes

    International Nuclear Information System (INIS)

    Ren, J.; Kang, T.F.; Xue, R.; Ge, C.N.; Cheng, S.Y.

    2011-01-01

    We describe a biosensor for phenolic compounds that is based on a glassy carbon electrode modified with tyrosinase immobilized on multiwalled carbon nanotubes (MWNTs). The MWNTs possess excellent inherent electrical conductivity which enhances the electron transfer rate and results in good electrochemical catalytic activity towards the reduction of benzoquinone produced by enzymatic reaction. The biosensor was characterized by cyclic voltammetry, and the experimental conditions were optimized. The cathodic current is linearly related to the concentration of the phenols between 0.4 μM and 10 μM, and the detection limit is 0.2 μM. The method was applied to the determination of phenol in water samples (author)

  7. Tyrosinase inhibitor screening in traditional Chinese medicines by electrophoretically mediated microanalysis.

    Science.gov (United States)

    Tang, Lilin; Zhang, Wenpeng; Zhao, Haiyan; Chen, Zilin

    2015-08-01

    A capillary-electrophoresis-based method for the screening of tyrosinase inhibitors in traditional Chinese medicines was developed. The method integrated electrophoretically mediated microanalysis with sandwich mode injection, partial filling, and rapid polarity switching techniques, and carried out on-column enzyme reaction and the separation of substrate and product. The conditions were optimized including the background electrolyte, mixing voltage, and the incubation time. Finally, the screening of nine standard natural compounds of traditional Chinese medicines was carried out. The inhibitors can be directly identified from the reduced peak area of the product compared to that obtained without any inhibitor. Chlorogenic acid (100 μM) showed inhibitory activity with the inhibitory percentage of 19.8%, while the other compounds showed no inhibitory activity. This method has great application potential in drug discovery from traditional Chinese medicines. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Phenolic composition, antioxidant, anti-wrinkles and tyrosinase inhibitory activities of cocoa pod extract.

    Science.gov (United States)

    Karim, Azila Abdul; Azlan, Azrina; Ismail, Amin; Hashim, Puziah; Abd Gani, Siti Salwa; Zainudin, Badrul Hisyam; Abdullah, Nur Azilah

    2014-10-07

    Cocoa pod is an outer part of cocoa fruits being discarded during cocoa bean processing. Authors found out that data on its usage in literature as cosmetic materials was not recorded in vast. In this study, cocoa pod extract was investigated for its potential as a cosmetic ingredient. Cocoa pod extract (CPE) composition was accomplished using UHPLC. The antioxidant capacity were measured using scavenging assay of 1,2-diphenyl-2-picrylhydrazyl (DPPH), β-carotene bleaching assay (BCB) and ferric reducing antioxidant power (FRAP). Inhibiting effect on skin degradation enzymes was carried out using elastase and collagenase assays. The skin whitening effect of CPE was determined based on mushroom tyrosinase assay and sun screening effect (UV-absorbance at 200-400 nm wavelength). LC-MS/MS data showed the presence of carboxylic acid, phenolic acid, fatty acid, flavonoids (flavonol and flavones), stilbenoids and terpenoids in CPE. Results for antioxidant activity exhibited that CPE possessed good antioxidant activity, based on the mechanism of the assays compared with ascorbic acid (AA) and standardized pine bark extract (PBE); DPPH: AA > CPE > PBE; FRAP: PBE > CPE > AA; and BCB: BHT > CPE > PBE. Cocoa pod extract showed better action against elastase and collagenase enzymes in comparison with PBE and AA. Higher inhibition towards tyrosinase enzyme was exhibited by CPE than kojic acid and AA, although lower than PBE. CPE induced proliferation when tested on human fibroblast cell at low concentration. CPE also exhibited a potential as UVB sunscreen despite its low performance as a UVA sunscreen agent. Therefore, the CPE has high potential as a cosmetic ingredient due to its anti-wrinkle, skin whitening, and sunscreen effects.

  9. Nanostructured progesterone immunosensor using a tyrosinase-colloidal gold-graphite-Teflon biosensor as amperometric transducer

    Energy Technology Data Exchange (ETDEWEB)

    Carralero, Veronica [Department of Analytical Chemistry, Faculty of Chemistry, University Complutense of Madrid, 28040 Madrid (Spain); Gonzalez-Cortes, Araceli [Department of Analytical Chemistry, Faculty of Chemistry, University Complutense of Madrid, 28040 Madrid (Spain); Yanez-Sedeno, Paloma [Department of Analytical Chemistry, Faculty of Chemistry, University Complutense of Madrid, 28040 Madrid (Spain)]. E-mail: yseo@quim.ucm.es; Pingarron, Jose M. [Department of Analytical Chemistry, Faculty of Chemistry, University Complutense of Madrid, 28040 Madrid (Spain)

    2007-07-16

    A novel progesterone immunosensor using a colloidal gold-graphite-Teflon-tyrosinase composite biosensor as amperometric transducer is reported. A sequential competitive configuration between the analyte and progesterone labelled with alkaline phosphatase (AP) was used. Phenyl phosphate was employed as the AP-substrate and the enzyme reaction product, phenol, was oxidized by tyrosinase to o-quinone, which is subsequently reduced at -0.1 V at the biocomposite electrode. Variables such as the concentration of phenyl phosphate, the amount of antibody attached to the electrode surface, immersion time in a 2% BSA solution, working pH and incubation times in progesterone and AP conjugate were optimized. A linear calibration graph for progesterone was obtained between 0 and 40 ng mL{sup -1} with a slope value of -82.3 nA ng{sup -1} mL, and a detection limit of 0.43 ng mL{sup -1}. The time needed to reach the steady-state current from the addition of phenyl phosphate was 30-40 s. These analytical characteristics improve substantially those reported for other progesterone immunosensors. A lifetime of 14 days with no need to apply any regeneration procedure was also achieved. The usefulness of the immunosensor was evaluated by determining progesterone in milk samples spiked with the analyte at 5.0 and 1.5 ng mL{sup -1} concentration levels. Following a very simple procedure, involving only sample dilution, mean recoveries (n = 7) of 98 {+-} 3% and 99 {+-} 3%, respectively, were obtained.

  10. A novel fluorescent biosensor for adrenaline detection and tyrosinase inhibitor screening.

    Science.gov (United States)

    Liu, Ziping; Liu, Shasha

    2018-04-17

    In this work, a novel simple fluorescent biosensor for the highly sensitive and selective detection of adrenaline was established. Firstly, water-soluble CuInS 2 quantum dots (QDs) capped by L-Cys were synthesized via a hydrothermal synthesis method. Then, the positively charged adrenaline was assembled on the surface of CuInS 2 QDs due to the electrostatic interactions and hydrogen bonding, which led to the formation of adrenaline-CuInS 2 QD (Adr-CuInS 2 QD) electrostatic complexes. Tyrosinase (TYR) can catalyze adrenaline to generate H 2 O 2 , and additionally oxidize the adrenaline to adrenaline quinone. Both the H 2 O 2 and the adrenaline quinone can quench the fluorescence of the CuInS 2 QDs through the electron transfer (ET) process. Thus, the determination of adrenaline could be facilely achieved by taking advantage of the fluorescence "turn off" feature of CuInS 2 QDs. Under the optimum conditions, the fluorescence quenching ratio I f /I f0 (I f and I f0 were the fluorescence intensity of Adr-CuInS 2 QDs in the presence and absence of TYR, respectively) was proportional to the logarithm of adrenaline concentration in the range of 1 × 10 -8 -1 × 10 -4  mol L -1 with the detection limit of 3.6 nmol L -1 . The feasibility of the proposed biosensor in real sample assay was also studied and satisfactory results were obtained. Significantly, the proposed fluorescent biosensor can also be utilized to screen TYR inhibitors. Graphical abstract Schematic illustration of the fluorescent biosensor for adrenaline detection (A) and tyrosinase inhibitor screening (B).

  11. Nanostructured progesterone immunosensor using a tyrosinase-colloidal gold-graphite-Teflon biosensor as amperometric transducer

    International Nuclear Information System (INIS)

    Carralero, Veronica; Gonzalez-Cortes, Araceli; Yanez-Sedeno, Paloma; Pingarron, Jose M.

    2007-01-01

    A novel progesterone immunosensor using a colloidal gold-graphite-Teflon-tyrosinase composite biosensor as amperometric transducer is reported. A sequential competitive configuration between the analyte and progesterone labelled with alkaline phosphatase (AP) was used. Phenyl phosphate was employed as the AP-substrate and the enzyme reaction product, phenol, was oxidized by tyrosinase to o-quinone, which is subsequently reduced at -0.1 V at the biocomposite electrode. Variables such as the concentration of phenyl phosphate, the amount of antibody attached to the electrode surface, immersion time in a 2% BSA solution, working pH and incubation times in progesterone and AP conjugate were optimized. A linear calibration graph for progesterone was obtained between 0 and 40 ng mL -1 with a slope value of -82.3 nA ng -1 mL, and a detection limit of 0.43 ng mL -1 . The time needed to reach the steady-state current from the addition of phenyl phosphate was 30-40 s. These analytical characteristics improve substantially those reported for other progesterone immunosensors. A lifetime of 14 days with no need to apply any regeneration procedure was also achieved. The usefulness of the immunosensor was evaluated by determining progesterone in milk samples spiked with the analyte at 5.0 and 1.5 ng mL -1 concentration levels. Following a very simple procedure, involving only sample dilution, mean recoveries (n = 7) of 98 ± 3% and 99 ± 3%, respectively, were obtained

  12. Xenogeneic murine tyrosinase DNA vaccine for malignant melanoma of the digit of dogs.

    Science.gov (United States)

    Manley, C A; Leibman, N F; Wolchok, J D; Rivière, I C; Bartido, S; Craft, D M; Bergman, P J

    2011-01-01

    Malignant melanoma of dogs is a highly aggressive neoplasm and is the 2nd most common digit tumor. Metastatic disease is a common sequela for which few effective treatment options exist. Studies show that xenogeneic tyrosinase DNA vaccination yields immune responses and prolongation of survival in dogs with oral malignant melanoma. Describe clinical findings and tumor characteristics of a cohort of dogs with digit malignant melanoma, and evaluate the prognostic utility of a proposed staging system. Determine if a novel xenogeneic DNA vaccine is safe and potentially effective for treatment of dogs with digit melanoma. Fifty-eight dogs with digit malignant melanoma treated at the Animal Medical Center between 2004 and 2007. Retrospective, medical records review of dogs with digit melanoma treated with xenogeneic DNA vaccine. Overall median survival time (MST) for dogs treated with loco-regional control and xenogeneic DNA vaccine was 476 days with a 1-year survival rate of 63%. MST for dogs presenting with metastasis was 105 days versus 533 days for dogs presenting without metastasis (P dogs in the latter group were alive at 2 and 3 years. A proposed staging system proved prognostic with stages I-IV dogs surviving >952, >1,093, 321, and 76 days, respectively. The xenogeneic murine tyrosinase DNA vaccine was safe and appears effective when used in conjunction with local and regional disease control. The proposed staging system was prognostic in this study and future studies might benefit from utilizing this staging system. Copyright © 2010 by the American College of Veterinary Internal Medicine.

  13. Camellia sinensis L. Extract and Its Potential Beneficial Effects in Antioxidant, Anti-Inflammatory, Anti-Hepatotoxic, and Anti-Tyrosinase Activities

    Directory of Open Access Journals (Sweden)

    Surached Thitimuta

    2017-03-01

    Full Text Available The aims of this study were to investigate the potential benefits of antioxidant, anti-inflammatory, anti-hepatotoxic, and anti-tyrosinase activities of a methanolic extract of fresh tea leaves (FTE (Camellia sinensis L.. The antioxidant capacity was investigated using three different methods at different temperatures. The anti-inflammatory activity was studied in vitro by the inhibition of 5-lipoxygenase assay. The anti-hepatotoxic effect was investigated in CCl4-induced liver injury in rats. The anti-tyrosinase activities of the FTE and its principal phenolic compounds were investigated in l-3,4-dihydroxyphenylalanine (l-DOPA oxidation by a mushroom tyrosinase. A molecular docking study was conducted to determine how the FTE’s principal catechins interact with the tyrosinase. The FTE exhibited the best shelf life at low temperatures and demonstrated concentration-dependent antioxidant, anti-inflammatory, anti-hepatotoxic, and anti-tyrosinase effects compared to positive references. Treatment of rats with the FTE at 2000 mg/kg/day for 28 consecutive days reversed CCl4-induced oxidative damage in hepatic tissues by lowering the levels of alanine aminotransferase by 69% and malondialdehyde by 90%. Our findings suggest that the FTE has the capacity to scavenge free radicals and can protect against oxidative stress induced by CCl4 intoxication. The docking results were consistent with our in vitro data, indicating the anti-tyrosinase potency of the principal catechins.

  14. Camellia sinensis L. Extract and Its Potential Beneficial Effects in Antioxidant, Anti-Inflammatory, Anti-Hepatotoxic, and Anti-Tyrosinase Activities.

    Science.gov (United States)

    Thitimuta, Surached; Pithayanukul, Pimolpan; Nithitanakool, Saruth; Bavovada, Rapepol; Leanpolchareanchai, Jiraporn; Saparpakorn, Patchreenart

    2017-03-04

    The aims of this study were to investigate the potential benefits of antioxidant, anti-inflammatory, anti-hepatotoxic, and anti-tyrosinase activities of a methanolic extract of fresh tea leaves (FTE) ( Camellia sinensis L.). The antioxidant capacity was investigated using three different methods at different temperatures. The anti-inflammatory activity was studied in vitro by the inhibition of 5-lipoxygenase assay. The anti-hepatotoxic effect was investigated in CCl₄-induced liver injury in rats. The anti-tyrosinase activities of the FTE and its principal phenolic compounds were investigated in l-3,4-dihydroxyphenylalanine (l-DOPA) oxidation by a mushroom tyrosinase. A molecular docking study was conducted to determine how the FTE's principal catechins interact with the tyrosinase. The FTE exhibited the best shelf life at low temperatures and demonstrated concentration-dependent antioxidant, anti-inflammatory, anti-hepatotoxic, and anti-tyrosinase effects compared to positive references. Treatment of rats with the FTE at 2000 mg/kg/day for 28 consecutive days reversed CCl₄-induced oxidative damage in hepatic tissues by lowering the levels of alanine aminotransferase by 69% and malondialdehyde by 90%. Our findings suggest that the FTE has the capacity to scavenge free radicals and can protect against oxidative stress induced by CCl₄ intoxication. The docking results were consistent with our in vitro data, indicating the anti-tyrosinase potency of the principal catechins.

  15. Extracellular matrix structure.

    Science.gov (United States)

    Theocharis, Achilleas D; Skandalis, Spyros S; Gialeli, Chrysostomi; Karamanos, Nikos K

    2016-02-01

    Extracellular matrix (ECM) is a non-cellular three-dimensional macromolecular network composed of collagens, proteoglycans/glycosaminoglycans, elastin, fibronectin, laminins, and several other glycoproteins. Matrix components bind each other as well as cell adhesion receptors forming a complex network into which cells reside in all tissues and organs. Cell surface receptors transduce signals into cells from ECM, which regulate diverse cellular functions, such as survival, growth, migration, and differentiation, and are vital for maintaining normal homeostasis. ECM is a highly dynamic structural network that continuously undergoes remodeling mediated by several matrix-degrading enzymes during normal and pathological conditions. Deregulation of ECM composition and structure is associated with the development and progression of several pathologic conditions. This article emphasizes in the complex ECM structure as to provide a better understanding of its dynamic structural and functional multipotency. Where relevant, the implication of the various families of ECM macromolecules in health and disease is also presented. Copyright © 2015 Elsevier B.V. All rights reserved.

  16. Synthesis of chiral pyrazolo[4,3-e][1,2,4]triazine sulfonamides with tyrosinase and urease inhibitory activity.

    Science.gov (United States)

    Mojzych, Mariusz; Tarasiuk, Paweł; Kotwica-Mojzych, Katarzyna; Rafiq, Muhammad; Seo, Sung-Yum; Nicewicz, Michał; Fornal, Emilia

    2017-12-01

    A new series of sulfonamide derivatives of pyrazolo[4,3-e][1,2,4]triazine with chiral amino group has been synthesized and characterized. The compounds were tested for their tyrosinase and urease inhibitory activity. Evaluation of prepared derivatives demonstrated that compounds (8b) and (8j) are most potent mushroom tyrosinase inhibitors whereas all of the obtained compounds showed higher urease inhibitory activity than the standard thiourea. The compounds (8a), (8f) and (8i) exhibited excellent enzyme inhibitory activity with IC 50 0.037, 0.044 and 0.042 μM, respectively, while IC 50 of thiourea is 20.9 μM.

  17. Combining molecular docking and QSAR studies for modeling the anti-tyrosinase activity of aromatic heterocycle thiosemicarbazone analogues

    Science.gov (United States)

    Dong, Huanhuan; Liu, Jing; Liu, Xiaoru; Yu, Yanying; Cao, Shuwen

    2018-01-01

    A collection of thirty-six aromatic heterocycle thiosemicarbazone analogues presented a broad span of anti-tyrosinase activities were designed and obtained. A robust and reliable two-dimensional quantitative structure-activity relationship model, as evidenced by the high q2 and r2 values (0.848 and 0.893, respectively), was gained based on the analogues to predict the quantitative chemical-biological relationship and the new modifier direction. Inhibitory activities of the compounds were found to greatly depend on molecular shape and orbital energy. Substituents brought out large ovality and high highest-occupied molecular orbital energy values helped to improve the activity of these analogues. The molecular docking results provided visual evidence for QSAR analysis and inhibition mechanism. Based on these, two novel tyrosinase inhibitors O04 and O05 with predicted IC50 of 0.5384 and 0.8752 nM were designed and suggested for further research.

  18. Determination of Antioxidant, Anticholinesterase, Tyrosinase Inhibitory Activities and Fatty Acid Profiles of 10 Anatolian Klasea Cass. Species

    Directory of Open Access Journals (Sweden)

    Gülsen Tel

    2016-01-01

    Full Text Available In search of new natural fatty acid sources, extract of 10 different Turkish Klasea species were studies. Fatty acids of Klasea species were studied by GC and GC-MSD. Oleic acid (4.8-45.8%, palmitic acid (15.6-51.8%, linoleic acid (0.3-45.5%, palmitoleic acid (0.8-28.4% and linolenic acid (15.6-34.6% were the main fatty acids elucidated. All extracts were also subjected to acetylcholinesterase, butyrylcholinesterase, tyrosinase, β-carotene-linoleic acid, DPPH • scavenging, CUPRAC and ferrous ion-chelating ability activities. Total flavonoid and phenolic contents were determined as quercetin and pyrocatechol equivalents. All extracts showed significant antioxidant activity in all tests, except hexane extracts of K. serratuloides and K. cerinthifolia that showed weak inhibition against BChE and AChE. The hexane extract of K. coriaceae and methanol extract of K. serratuloides exhibited notable tyrosinase inhibitory activity.

  19. TLC-bioautographic evaluation of in vitro anti-tyrosinase and anti-cholinesterase potentials of sandalwood oil.

    Science.gov (United States)

    Misra, Biswapriya B; Dey, Satyahari

    2013-02-01

    Sandalwood oil, rich in sesquiterpenoid alcohols, has been used in traditional medicinal systems as a relaxant and coolant. Besides, sandalwood oil is used as an ingredient in numerous skin fairness enhancing cosmetics. However, there is no available information on biological activities that relate to the above applications. Hence, the anti-tyrosinase and anti-cholinesterase potentials of sandalwood oil were probed by both TLC-bioautographic and colorimetric methods. Results obtained from colorimetric assays indicated that sandalwood oil is a potent inhibitor of tyrosinase (IC50 = 171 microg mL(-1)) and cholinesterases (IC50 = 4.8-58 microg mL(-1)), in comparison with the positive controls used in the assays, kojic acid and physostigmine, respectively. The TLC-bioautographic assays indicated that alpha-santalol, the major constituent of the oil, is a strong inhibitor of both tyrosinase and cholinesterase. These in vitro results indicate that there is a great potential of this essential oil for use in the treatment of Alzheimer's disease, as well as in skin-care.

  20. Novel piperonal 1,3,4-thiadiazolium-2-phenylamines mesoionic derivatives: Synthesis, tyrosinase inhibition evaluation and HSA binding study.

    Science.gov (United States)

    Lopes, Natália Drumond; Chaves, Otávio Augusto; de Oliveira, Márcia C C; Sant'Anna, Carlos Mauricio R; Sousa-Pereira, Danilo; Netto-Ferreira, José Carlos; Echevarria, Aurea

    2018-06-01

    A novel series of piperonal mesoionic derivatives (PMI 1-6) was synthesized. Tyrosinase inhibition in the presence of PMI-1, -2, -3, -4, -5 and -6 as well as human serum albumin (HSA) binding studies with PMI-5 and PMI-6 were done by spectroscopic and theoretical methods. The mesoionic compound PMI-5 is the most promising tyrosinase inhibitor with a noncompetitive inhibitory mechanism and an IC 50 =124μmolL -1 . In accordance with the kinetic profile, molecular docking results show that PMI-5 is able to interact favorably with the tyrosinase active site containing the substrate molecule, L-DOPA, interacting with Val-247, Phe-263 and Val-282 residues. The spectroscopic results for the interaction HSA:PMI-5 and HSA:PMI-6 indicated that these mesoionic compounds can associate with HSA in the ground state and energy transfer can occur with high probability. The binding was moderate, spontaneous and can perturb significantly the secondary structure of the albumin. The molecular docking results suggest that PMI-5 and PMI-6 are able to be accommodated inside the Sudlow's site I in HSA, interacting with hydrophobic and hydrophilic amino acid residues. Copyright © 2018 Elsevier B.V. All rights reserved.

  1. Dermal extracellular lipid in birds.

    Science.gov (United States)

    Stromberg, M W; Hinsman, E J; Hullinger, R L

    1990-01-01

    A light and electron microscopic study of the skin of domestic chickens, seagulls, and antarctic penguins revealed abundant extracellular dermal lipid and intracellular epidermal lipid. Dermal lipid appeared ultrastructurally as extracellular droplets varying from less than 1 micron to more than 25 microns in diameter. The droplets were often irregularly contoured, sometimes round, and of relatively low electron density. Processes of fibrocytes were often seen in contact with extracellular lipid droplets. Sometimes a portion of such a droplet was missing, and this missing part appeared to have been "digested away" by the cell process. In places where cells or cell processes are in contact with fact droplets, there are sometimes extracellular membranous whorls or fragments which have been associated with the presence of fatty acids. Occasionally (in the comb) free fat particles were seen in intimate contact with extravasated erythrocytes. Fat droplets were seen in the lumen of small dermal blood and lymph vessels. We suggest that the dermal extracellular lipid originates in the adipocyte layer and following hydrolysis the free fatty acids diffuse into the epidermis. Here they become the raw material for forming the abundant neutral lipid contained in many of the epidermal cells of both birds and dolphins. The heretofore unreported presence and apparently normal utilization of abundant extracellular lipid in birds, as well as the presence of relatively large droplets of neutral lipid in dermal vessels, pose questions which require a thorough reappraisal of present concepts of the ways in which fat is distributed and utilized in the body.

  2. In vivo modification of tyrosine residues in recombinant mussel adhesive protein by tyrosinase co-expression in Escherichia coli

    Directory of Open Access Journals (Sweden)

    Choi Yoo

    2012-10-01

    Full Text Available Abstract Background In nature, mussel adhesive proteins (MAPs show remarkable adhesive properties, biocompatibility, and biodegradability. Thus, they have been considered promising adhesive biomaterials for various biomedical and industrial applications. However, limited production of natural MAPs has hampered their practical applications. Recombinant production in bacterial cells could be one alternative to obtain useable amounts of MAPs, although additional post-translational modification of tyrosine residues into 3,4-dihydroxyphenyl-alanine (Dopa and Dopaquinone is required. The superior properties of MAPs are mainly attributed to the introduction of quinone-derived intermolecular cross-links. To solve this problem, we utilized a co-expression strategy of recombinant MAP and tyrosinase in Escherichia coli to successfully modify tyrosine residues in vivo. Results A recombinant hybrid MAP, fp-151, was used as a target for in vivo modification, and a dual vector system of pET and pACYC-Duet provided co-expression of fp-151 and tyrosinase. As a result, fp-151 was over-expressed and mainly obtained from the soluble fraction in the co-expression system. Without tyrosinase co-expression, fp-151 was over-expressed in an insoluble form in inclusion bodies. The modification of tyrosine residues in the soluble-expressed fp-151 was clearly observed from nitroblue tetrazolium staining and liquid-chromatography-mass/mass spectrometry analyses. The purified, in vivo modified, fp-151 from the co-expression system showed approximately 4-fold higher bulk-scale adhesive strength compared to in vitro tyrosinase-treated fp-151. Conclusion Here, we reported a co-expression system to obtain in vivo modified MAP; additional in vitro tyrosinase modification was not needed to obtain adhesive properties and the in vivo modified MAP showed superior adhesive strength compared to in vitro modified protein. It is expected that this co-expression strategy will accelerate

  3. A cDNA Cloning of a Novel Alpha-Class Tyrosinase of Pinctada fucata: Its Expression Analysis and Characterization of the Expressed Protein

    Directory of Open Access Journals (Sweden)

    Ryousuke Takgi

    2014-01-01

    Full Text Available Tyrosinase plays an important role in the formation of the shell matrix and melanin synthesis in mollusks shells. A cDNA clone encoding a 47 kDa protein was isolated from the pearl oyster Pinctada fucata. The cDNA was 1,957 base pairs long and encodes a 417 residue protein that has extensive sequence identity with tyrosinase (polyphenol oxidase: EC 1.14.18.1. This tyrosinase-like protein, termed PfTy, contains an N-terminal signal sequence and the two copper-binding domain signatures (CuA and CuB, suggesting that PfTy belongs to the α-subclass of type-3 copper proteins. Enzyme activity of PfTy was examined by a spectrophotometric method using the translation product derived from an S30 T7 high-yield protein expression system. Tyrosinase activity was seen in this recombinant product. RT-PCR analysis showed that PfTy mRNA was expressed in the mantle pallial, but not in the mantle edge. Therefore, PfTy may participate in insoluble shell matrix formation of the nacreous layer. PfTy expression was also observed in the foot, liver, and adductor muscle, suggesting that PfTy participates in the synthesis of melanins, which are effective scavengers of free radicals formed in multiple intracellular oxidative processes. This is the first report of a novel α-class tyrosinase from the pearl oyster P. fucata.

  4. New insights into highly potent tyrosinase inhibitors based on 3-heteroarylcoumarins: Anti-melanogenesis and antioxidant activities, and computational molecular modeling studies.

    Science.gov (United States)

    Pintus, Francesca; Matos, Maria J; Vilar, Santiago; Hripcsak, George; Varela, Carla; Uriarte, Eugenio; Santana, Lourdes; Borges, Fernanda; Medda, Rosaria; Di Petrillo, Amalia; Era, Benedetta; Fais, Antonella

    2017-03-01

    Melanogenesis is a physiological pathway for the formation of melanin. Tyrosinase catalyzes the first step of this process and down-regulation of its activity is responsible for the inhibition of melanogenesis. The search for molecules capable of controlling hyperpigmentation is a trend topic in health and cosmetics. A series of heteroarylcoumarins have been synthesized and evaluated. Compounds 4 and 8 exhibited higher tyrosinase inhibitory activities (IC 50 =0.15 and 0.38μM, respectively), than the reference compound, kojic acid (IC 50 =17.9μM). Compound 4 acts as competitive, while compound 8 as uncompetitive inhibitor of mushroom tyrosinase. Furthermore, compounds 2 and 8 inhibited tyrosinase activity and melanin production in B16F10 cells. In addition, compounds 2-4 and 8 proved to have an interesting antioxidant profile in both ABTS and DPPH radicals scavenging assays. Docking experiments were carried out in order to study the interactions between these heteroarylcoumarins and mushroom tyrosinase. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. Neurospora crassa glucose - repressible gene -1(Grg-1) promoter controls the expression of neurospora tyrosinase gene in a clock-controlled manner

    International Nuclear Information System (INIS)

    Tarawneh, A. K

    1997-01-01

    In this study sphareroplastes of white Neurospora crassa mutant auxotroph for aromatic am no acids a rom 9 q a-2 inv, was transformed by the pKF-Tyr7-wt DNA construct. This construct contains the promoter of neurospora crassa glucose-repressible gene-1 (G rg-1) usp stream of Neurospora tyrosinase gene. The co transformation of this mutant with pKF-Tyr-7-wt cincture's and the pKAL-1, a plasmid which contains the Neurospora q a-2+ gene transform it to photophor. The transform ant contains the tyrosinase gene which catalyzes the unique step in the synthesis of the black pigment melanin. The activity of the tyrosinase in this transform ant was followed by measuring the absorbance of the dark coloured pigment at 332 nm. The maximum of the tyrosinase activity was shown at 16.36 and 56 hours after the shift of the transformed mycelia from constant light (L L) to constant dark (Dd). The rate of the enzyme activity was changed according to ci radian cycle of 20 hours. This G rg 1/tyrosinase construct provides a good system to study to study the temporal control of gene expression and the interaction between the different environmental c uses that affects gene expression. (author). 20 refs., 4 figs

  6. Immobilization of Tyrosinase from Avocado Crude Extract in Polypyrrole Films for Inhibitive Detection of Benzoic Acid

    Directory of Open Access Journals (Sweden)

    André Brisolari

    2014-07-01

    Full Text Available Inhibition-based biosensors were developed by immobilizing tyrosinase (Tyr, polyphenol oxidase from the crude extract of avocado fruit on electrochemically prepared polypyrrole (PPy films. The biosensors were prepared during the electropolymerization of pyrrole in a solution containing a fixed volume of the crude extract of avocado. The dependence of the biosensor responses on the volume used from the crude extract, values of pH and temperature was studied, and a substrate, catechol, at different concentrations, was amperometrically detected by these biosensors. Benzoic acid, a competitive inhibitor of Try, was added to the catechol solutions at specific concentrations aimed at obtaining the inhibition constant, K’m, which ranged from 1.7 to 4.6 mmol∙L−1 for 0.0 and 60 µmol∙L−1 of benzoic acid, respectively. Studies on the inhibition caused by benzoic acid by using PPy/Try films, and catechol as a substrate, allowed us propose how to develop, under optimized conditions, simple and low-cost biosensors based on the use of avocado fruit.

  7. Albinism in the domestic cat (Felis catus) is associated with a tyrosinase (TYR) mutation

    Science.gov (United States)

    Imes, DL; Geary, LA; Grahn, RA; Lyons, LA

    2006-01-01

    Summary Albino phenotypes are documented in a variety of species including the domestic cat. As albino phenotypes in other species are associated with tyrosinase (TYR) mutations, TYR was proposed as a candidate gene for albinism in cats. An Oriental and Colourpoint Shorthair cat pedigree segregating for albinism was analysed for association with TYR by linkage and sequence analyses. Microsatellite FCA931, which is closely linked to TYR and TYR sequence variants were tested for segregation with the albinism phenotype. Sequence analysis of genomic DNA from wild-type and albino cats identified a cytosine deletion in TYR at position 975 in exon 2, which causes a frame shift resulting in a premature stop codon nine residues downstream from the mutation. The deletion mutation in TYR and an allele of FCA931 segregated concordantly with the albino phenotype. Taken together, our results suggest that the TYR gene corresponds to the colour locus in cats and its alleles, from dominant to recessive, are as follows: C (full colour) > cb (burmese) ≥ cs (siamese) > c (albino). PMID:16573534

  8. Effects of Gold Nanoparticles on the Response of Phenol Biosensor Containing Photocurable Membrane with Tyrosinase

    Directory of Open Access Journals (Sweden)

    Ahmad Musa

    2008-10-01

    Full Text Available The role of incorporation of gold nanoparticles (50-130 nm in diameter into a series of photocurable methacrylic-acrylic based biosensor membranes containing tyrosinase on the response for phenol detection was investigated. Membranes with different hydrophilicities were prepared from 2-hydroxyethyl methacrylate and n-butyl acrylate via direct photocuring. A range of gold nanoparticles concentrations from 0.01 to 0.5 % (w/w was incorporated into these membranes during the photocuring process. The addition of gold nanoparticles to the biosensor membrane led to improvement in the response time by a reduction of approximately 5 folds to give response times of 5-10 s. The linear response range of the phenol biosensor was also extended from 24 to 90 mM of phenol. The hydrophilicities of the membrane matrices demonstrated strong influence on the biosensor response and appeared to control the effect of the gold nanoparticles. For less hydrophilic methacrylic-acrylic membranes, the addition of gold nanoparticles led to a poorer sensitivity and detection limit of the biosensor towards phenol. Therefore, for the application of gold nanoparticles in the enhancement of a phenol biosensor response, the nanoparticles should be immobilized in a hydrophilic matrix rather than a hydrophobic material.

  9. Validating tyrosinase homologue MelA as a photoacoustic reporter gene for imaging Escherichia coli

    Science.gov (United States)

    Paproski, Robert J.; Li, Yan; Barber, Quinn; Lewis, John D.; Campbell, Robert; Zemp, Roger

    2015-03-01

    Antibiotic drug resistance is a major worldwide issue. Development of new therapies against pathogenic bacteria requires appropriate research tools for replicating and characterizing infections. Previously fluorescence and bioluminescence modalities have been used to image infectious burden in animal models but scattering significantly limits imaging depth and resolution. We hypothesize that photoacoustic imaging, which has improved depth-toresolution ratio, could be useful for visualizing MelA-expressing bacteria since MelA is a bacterial tyrosinase homologue involved in melanin production. Using an inducible expression system, E. coli expressing MelA were visibly black in liquid culture. Phosphate buffered saline (PBS), MelA-expressing bacteria (at different dilutions in PBS), and chicken embryo blood were injected in plastic tubes which were imaged using a VisualSonics Vevo LAZR system. Photoacoustic imaging at 6 different wavelengths (680, 700, 750, 800, 850 and 900nm) enabled spectral de-mixing to distinguish melanin signals from blood. The signal to noise ratio of 9x diluted MelA bacteria was 55, suggesting that ~20 bacteria cells could be detected with our system. When MelA bacteria were injected as a 100 μL bolus into a chicken embryo, photoacoustic signals from deoxy- and oxy- hemoglobin as well as MelA-expressing bacteria could be separated and overlaid on an ultrasound image, allowing visualization of the bacterial location. Photoacoustic imaging may be a useful tool for visualizing bacterial infections and further work incorporating photoacoustic reporters into infectious bacterial strains is warranted.

  10. Detection of methyl salicylate using bi-enzyme electrochemical sensor consisting salicylate hydroxylase and tyrosinase.

    Science.gov (United States)

    Fang, Yi; Bullock, Hannah; Lee, Sarah A; Sekar, Narendran; Eiteman, Mark A; Whitman, William B; Ramasamy, Ramaraja P

    2016-11-15

    Volatile organic compounds have been recognized as important marker chemicals to detect plant diseases caused by pathogens. Methyl salicylate has been identified as one of the most important volatile organic compounds released by plants during a biotic stress event such as fungal pathogen infection. Advanced detection of these marker chemicals could help in early identification of plant diseases and has huge significance for agricultural industry. This work describes the development of a novel bi-enzyme based electrochemical biosensor consisting of salicylate hydroxylase and tyrosinase enzymes immobilized on carbon nanotube modified electrodes. The amperometric detection using the bi-enzyme platform was realized through a series of cascade reactions that terminate in an electrochemical reduction reaction. Electrochemical measurements revealed that the sensitivity of the bi-enzyme sensor was 30.6±2.7µAcm(-2)µM(-1) and the limit of detection and limit of quantification were 13nM (1.80ppb) and 39nM (5.39ppb) respectively. Interference studies showed no significant interference from the other common plant volatile compounds. Synthetic analyte studies revealed that the bi-enzyme based biosensor can be used to reliably detect methyl salicylate released by unhealthy plants. Copyright © 2016. Published by Elsevier B.V.

  11. Extracellular gadolinium contrast agents: Differences in stability

    International Nuclear Information System (INIS)

    Morcos, S.K.

    2008-01-01

    Extracellular gadolinium contrast agents (Gd-CA) are either linear or macrocyclic chelates available as ionic or non-ionic preparations. The molecular structure whether cyclic or linear and ionicity determines the stability of Gd-CA. Linear chelates are flexible open chains which do not offer a strong binding to Gd 3+ . In contrast, the macrocyclic chelates offer a strong binding to Gd 3+ by the virtue of being preorganized rigid rings of almost optimal size to cage the gadolinium atom. Non-ionic preparations are also less stable in comparison to the ionic ones as the binding between Gd 3+ with the negatively charged carboxyl groups is stronger in comparison to that with amides or alcohol in the non-ionic preparations. According to stability constants and kinetic measurements, the most stable Gd-CM is the ionic-macrocyclic chelate Gd-DOTA and the least stable agents are the non-ionic linear chelates gadodiamide and gadoversetamide. In vivo data confirmed the low stability of non-ionic linear chelates but no significant difference was observed amongst the macrocyclic agents whether ionic (Gd-DOTA) or non-ionic such as Gd-HP-DO3A and Gd-BT-DO3A. The stability of Gd-CA seems to be an important factor in the pathogenesis of the serious complication of nephrogenic systemic fibrosis. Gd-CA of low stability are likely to undergo transmetallation and release free Gd ions that deposit in tissue and attract circulating fibrocytes to initiate the process of fibrosis. No cases of NSF have been observed so far after the exclusive use of the stable macrocyclic Gd-CA

  12. Occurrence State and Molecular Structure Analysis of Extracellular Proteins with Implications on the Dewaterability of Waste-Activated Sludge.

    Science.gov (United States)

    Wu, Boran; Ni, Bing-Jie; Horvat, Kristine; Song, Liyan; Chai, Xiaoli; Dai, Xiaohu; Mahajan, Devinder

    2017-08-15

    The occurrence state and molecular structure of extracellular proteins were analyzed to reveal the influencing factors on the water-holding capacities of protein-like substances in waste-activated sludge (WAS). The gelation process of extracellular proteins verified that advanced oxidation processes (AOPs) for WAS dewaterability improvement eliminated the water affinity of extracellular proteins and prevented these macromolecules from forming stable colloidal aggregates. Isobaric tags for relative and absolute quantitation proteomics identified that most of the extracellular proteins were originally derived from the intracellular part and the proteins originally located in the extracellular part were mainly membrane-associated. The main mechanism of extracellular protein transformation during AOPs could be represented by the damage of the membrane or related external encapsulating structure and the release of intracellular substances. For the selected representative extracellular proteins, the strong correlation (R 2 > 0.97, p proteins on the interstitial water removal from WAS.

  13. Stable Isotope Data

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Tissue samples (skin, bone, blood, muscle) are analyzed for stable carbon, stable nitrogen, and stable sulfur analysis. Many samples are used in their entirety for...

  14. Solvent 1H/2H isotopic effects in the reaction of the L-Tyrosine oxidation catalyzed by Tyrosinase

    International Nuclear Information System (INIS)

    Kozlowska, M.; Kanska, M.

    2006-01-01

    Tyrosinase is well known catalyst in the oxidation of L-Tyrosine to L-DOPA and following oxidation of L-DOPA to dopachinone. The aim of communication is to present the results of studies on the solvent isotopic effects (SIE) in the above reactions for the 1 H/ 2 H in the 3',5' and 2',6' substituted tyrosine. Obtained dependence of the reaction rate on the substrate concentration were applied for optimization of the kinetic parameters, k cat and k cat /K m , in the Michaelis-Menten equation. As a result - better understanding of the L-DOPA creation can be achieved

  15. Sensitive amperometric biosensor for phenolic compounds based on graphene-silk peptide/tyrosinase composite nanointerface.

    Science.gov (United States)

    Qu, Ying; Ma, Ming; Wang, Zhengguo; Zhan, Guoqing; Li, Buhai; Wang, Xian; Fang, Huaifang; Zhang, Huijuan; Li, Chunya

    2013-06-15

    New graphene-silk peptide (Gr-SP) nanosheets were prepared and successfully fabricated with tyrosinase (Tyr) as a novel biosensor for the determination of phenolic compounds. The Gr-SP nanosheets were fully characterized with transmission electron microscopy, x-ray diffraction, x-ray photoelectron spectroscopy, UV/Vis and FTIR spectra. The developed biosensors were also characterized with scanning electronic microscopy and electrochemical impedance spectroscopy. Using bisphenol A (BPA) as a model substrate in the sensing system, a number of key factors including the volume of Gr-SP-Tyr solution, the applied potential, pH values, temperature, and the Tyr/Gr-SP ratio that influence the analytical performance of the biosensor were investigated. The biosensor gave a linear response on the concentration ranges of 0.001-16.91 μM for catechol with the sensitivity of 7634 mA M(-1)cm(-2), 0.0015-21.12 μM for phenol with the sensitivity of 4082 mA M(-1)cm(-2), and 0.002-5.48 μM for BPA with the sensitivity of 2511 mA M(-1)cm(-2). The low detection limits were estimated to be 0.23, 0.35 and 0.72 nM (S/N=3) for catechol, phenol and BPA, respectively. The biosensors also exhibit good repeatability and long-term stability. The practical application of the biosensor was also demonstrated by the determination of BPA leaching from commercial plastic drinking bottles. Copyright © 2013 Elsevier B.V. All rights reserved.

  16. Structure-based function prediction of the expanding mollusk tyrosinase family

    Science.gov (United States)

    Huang, Ronglian; Li, Li; Zhang, Guofan

    2017-11-01

    Tyrosinase (Ty) is a common enzyme found in many different animal groups. In our previous study, genome sequencing revealed that the Ty family is expanded in the Pacific oyster ( Crassostrea gigas). Here, we examine the larger number of Ty family members in the Pacific oyster by high-level structure prediction to obtain more information about their function and evolution, especially the unknown role in biomineralization. We verified 12 Ty gene sequences from Crassostrea gigas genome and Pinctada fucata martensii transcriptome. By using phylogenetic analysis of these Tys with functionally known Tys from other molluscan species, eight subgroups were identified (CgTy_s1, CgTy_s2, MolTy_s1, MolTy-s2, MolTy-s3, PinTy-s1, PinTy-s2 and PviTy). Structural data and surface pockets of the dinuclear copper center in the eight subgroups of molluscan Ty were obtained using the latest versions of prediction online servers. Structural comparison with other Ty proteins from the protein databank revealed functionally important residues (HA1, HA2, HA3, HB1, HB2, HB3, Z1-Z9) and their location within these protein structures. The structural and chemical features of these pockets which may related to the substrate binding showed considerable variability among mollusks, which undoubtedly defines Ty substrate binding. Finally, we discuss the potential driving forces of Ty family evolution in mollusks. Based on these observations, we conclude that the Ty family has rapidly evolved as a consequence of substrate adaptation in mollusks.

  17. Condensed tannins from Ficus virens as tyrosinase inhibitors: structure, inhibitory activity and molecular mechanism.

    Directory of Open Access Journals (Sweden)

    Xiao-Xin Chen

    Full Text Available Condensed tannins from Ficus virens leaves, fruit, and stem bark were isolated and their structures characterized by 13C nuclear magnetic resonance spectrometry, high performance liquid chromatography electrospray ionization mass spectrometry, and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. The results showed that the leaves, fruit, and stem bark condensed tannins were complex mixtures of homo- and heteropolymers of B-type procyanidins and prodelphinidins with degrees of polymerization up to hexamer, dodecamer, and pentadecamer, respectively. Antityrosinase activities of the condensed tannins were studied. The results indicated that the condensed tannins were potent tyrosinase inhibitors. The concentrations for the leaves, fruit, and stem bark condensed tannins leading to 50% enzyme activity were determined to be 131.67, 99.89, and 106.22 μg/ml on monophenolase activity, and 128.42, 43.07, and 74.27 μg/ml on diphenolase activity. The inhibition mechanism, type, and constants of the condensed tannins on the diphenolase activity were further investigated. The results indicated that the condensed tannins were reversible and mixed type inhibitors. Fluorescence quenching, copper interacting, and molecular docking techniques were utilized to unravel the molecular mechanisms of the inhibition. The results showed that the hydroxyl group on the B ring of the condensed tannins could chelate the dicopper irons of the enzyme. Moreover, the condensed tannins could reduce the enzyme product o-quinones into colourless compounds. These results would contribute to the development and design of antityrosinase agents.

  18. Kinetic, Thermodynamic and Structural Studies of Native and N-Bromosuccinimide-Modified Mushroom Tyrosinase

    Directory of Open Access Journals (Sweden)

    Saeed Emami

    2016-10-01

    Full Text Available Background Mushroom tyrosinase (MT as a metalloenzyme is a good model for mechanistic studies of melanogenesis. To recognize the mechanism of MT action, it is important to investigate its inhibition, activation, mutation, and modification properties. Objectives In this study, the chemical modification of MT tryptophan residues was carried out by using N-bromosuccinimide (NBS and then, the activity, stability, and structure of the native and modified enzymes were compared. Methods Chemical modification of MT tryptophan residues was accomplished by enzyme incubation with different concentrations of NBS. The relative activity of native and modified MT was investigated through catecholase enzyme reaction in presence of dihydroxyphenylalanine (L-Dopa as substrate. Thermodynamic parameters including standard Gibbs free energy change (∆G25°C and Melting temperature (Tm were obtained from thermal denaturation of the native and modified enzymes. The circular dichroism and intrinsic fluorescence techniques were used to study secondary and tertiary structure of MT, respectively. All experiments were conducted in 2015 in biophysical laboratory of Qazvin University of Medical Sciences and Islamic Azad University, Science and Research Branch, Tehran. Results The relative activity reduced from 100% for native enzyme to 10%, 7.9%, and 6.4% for modified MT with different NBS of concentrations 2, 10, and 20 mM, respectively. Thermal instability of modified enzyme was confirmed by decreased Tm and ∆G25°C values after modification. In accordance with kinetic and thermodynamic results, the lower stability of modified MT was observed from the changes occurred on its secondary and tertiary structures. Conclusions Chemical modification of tryptophan residues with NBS reduces the activity and stability of MT simultaneously with its structural change. Thus, this study emphasizes the crucial role of tryptophan residues in the structure-function relationship of MT

  19. Extracellular vesicles: Exosomes, microvesicles, and friends

    NARCIS (Netherlands)

    Raposo, G.; Stoorvogel, W.|info:eu-repo/dai/nl/074352385

    2013-01-01

    Cells release into the extracellular environment diverse types of membrane vesicles of endosomal and plasma membrane origin called exosomes and microvesicles, respectively. These extracellular vesicles (EVs) represent an important mode of intercellular communication by serving as vehicles for

  20. The unfolded protein response in melanocytes: activation in response to chemical stressors of the endoplasmic reticulum and tyrosinase misfolding.

    Science.gov (United States)

    Manga, Prashiela; Bis, Sabina; Knoll, Kristen; Perez, Beremis; Orlow, Seth J

    2010-10-01

    Accumulation of proteins in the endoplasmic reticulum (ER) triggers the unfolded protein response (UPR), comprising three signaling pathways initiated by Ire1, Perk and Atf6 respectively. Unfolded protein response activation was compared in chemically stressed murine wildtype melanocytes and mutant melanocytes that retain tyrosinase in the ER. Thapsigargin, an ER stressor, activated all pathways in wildtype melanocytes, triggering Caspase 12-mediated apoptosis at toxic doses. Albino melanocytes expressing mutant tyrosinase showed evidence of ER stress with increased Ire1 expression, but the downstream effector, Xbp1, was not activated even following thapsigargin treatment. Attenuation of Ire1 signaling was recapitulated in wildtype melanocytes treated with thapsigargin for 8 days, with diminished Xbp1 activation observed after 4 days. Atf6 was also activated in albino melanocytes, with no response to thapsigargin, while the Perk pathway was not activated and thapsigargin treatment elicited robust expression of the downstream effector CCAAT-enhancer-binding protein homologous protein. Thus, melanocytes adapt to ER stress by attenuating two UPR pathways.

  1. Preparation of Au and Ag nanoparticles using Artemisia annua and their in vitro antibacterial and tyrosinase inhibitory activities

    Energy Technology Data Exchange (ETDEWEB)

    Basavegowda, Nagaraj; Idhayadhulla, Akber; Lee, Yong Rok, E-mail: yrlee@yu.ac.kr

    2014-10-01

    This work describes a plant-mediated approach to the preparation of metal nanoparticles using leaf extract of Artemisia annua (A. annua), an ethno-medicinal plant widely found in Asia, which was used as reducing and stabilizing agent. A. annua is used in traditional Chinese medicine to alleviate fever. Au and Ag nanoparticles were prepared using a one-step aqueous method at room temperature without any toxic chemicals. The formation of Au and Ag nanoparticles was monitored by UV–vis spectroscopy. Synthesized nanoparticles were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), energy dispersive X-ray analysis (EDX), Fourier transform infrared (FT-IR) spectroscopy, and thermogravimetric analysis (TGA). TEM analysis of Au nanoparticles showed that they had triangular and spherical shapes with sizes ranging from 15 to 40 nm. The silver nanoparticles were predominantly spherical and uniformly sized (30–50 nm). The Au and Ag nanoparticles produced showed significant tyrosinase inhibitory and antibacterial effects. These results suggest that the synthesized nanoparticles provide good alternatives in varied medical and industrial applications. - Highlights: • Au and Ag nanoparticles were synthesized using Artemisia annua leaf aqueous extract. • Nanoparticles were characterized by UV–vis spectroscopy, FT-IR, TEM, EDX, XRD, and TGA. • Au and Ag nanoparticles were of size 25 and 30 nm respectively, in spherical forms. • Nanoparticles showed significant tyrosinase inhibitory and antibacterial activities.

  2. Amperometric Biosensor Based on Zirconium Oxide/Polyethylene Glycol/Tyrosinase Composite Film for the Detection of Phenolic Compounds.

    Science.gov (United States)

    Ahmad, Nor Monica; Abdullah, Jaafar; Yusof, Nor Azah; Ab Rashid, Ahmad Hazri; Abd Rahman, Samsulida; Hasan, Md Rakibul

    2016-06-29

    A phenolic biosensor based on a zirconium oxide/polyethylene glycol/tyrosinase composite film for the detection of phenolic compounds has been explored. The formation of the composite film was expected via electrostatic interaction between hexacetyltrimethylammonium bromide (CTAB), polyethylene glycol (PEG), and zirconium oxide nanoparticles casted on screen printed carbon electrode (SPCE). Herein, the electrode was treated by casting hexacetyltrimethylammonium bromide on SPCE to promote a positively charged surface. Later, zirconium oxide was mixed with polyethylene glycol and the mixture was dropped cast onto the positively charged SPCE/CTAB. Tyrosinase was further immobilized onto the modified SPCE. Characterization of the prepared nanocomposite film and the modified SPCE surface was investigated by scanning electron microscopy (SEM), Electrochemical Impedance Spectroscopy (EIS), and Cyclic voltamogram (CV). The developed biosensor exhibits rapid response for less than 10 s. Two linear calibration curves towards phenol in the concentrations ranges of 0.075-10 µM and 10-55 µM with the detection limit of 0.034 µM were obtained. The biosensor shows high sensitivity and good storage stability for at least 30 days.

  3. Non-Essential Activation of Co"2"+ and Zn"2"+ on Mushroom Tyrosinase: Kinetic and Structural Stability

    International Nuclear Information System (INIS)

    Gheibi, N.; Sarreshtehdari, M.; Saboury, A. A.

    2011-01-01

    Tyrosinase is a widespread enzyme with great promising capabilities. The Lineweaver-Burk plots of the catecholase reactions showed that the kinetics of mushroom tyrosinase (MT), activated by Co"2"+ and Zn"2"+ at different pHs (6, 7, 8 and 9) obeyed the non-essential activation mode. The binding of metal ions to the enzyme increases the maximum velocity of the enzyme due to an increase in the enzyme catalytic constant (k_c_a_t). From the kinetic analysis, dissociation constants of the activator from the enzyme-metal ion complex (K_a) were obtained as 5 x 10"4 M"-"1 and 8.33 x 10"3 M"-"1 for Co"2"+ and Zn"2"+ at pH 9 and 6 respectively. The structural analysis of MT through circular dichroism (CD) and intensive fluorescence spectra revealed that the conformational stability of the enzyme in these pHs reaches its maximum value in the presence of each of the two metal ions

  4. A novel nonsense mutation in the tyrosinase gene is related to the albinism in a capuchin monkey (Sapajus apella).

    Science.gov (United States)

    Galante Rocha de Vasconcelos, Felipe Tadeu; Hauzman, Einat; Dutra Henriques, Leonardo; Kilpp Goulart, Paulo Roney; de Faria Galvão, Olavo; Sano, Ronaldo Yuiti; da Silva Souza, Givago; Lynch Alfaro, Jessica; de Lima Silveira, Luis Carlos; Fix Ventura, Dora; Oliveira Bonci, Daniela Maria

    2017-05-05

    Oculocutaneous Albinism (OCA) is an autosomal recessive inherited condition that affects the pigmentation of eyes, hair and skin. The OCA phenotype may be caused by mutations in the tyrosinase gene (TYR), which expresses the tyrosinase enzyme and has an important role in the synthesis of melanin pigment. The aim of this study was to identify the genetic mutation responsible for the albinism in a captive capuchin monkey, and to describe the TYR gene of normal phenotype individuals. In addition, we identified the subject's species. A homozygous nonsense mutation was identified in exon 1 of the TYR gene, with the substitution of a cytosine for a thymine nucleotide (C64T) at codon 22, leading to a premature stop codon (R22X) in the albino robust capuchin monkey. The albino and five non-albino robust capuchin monkeys were identified as Sapajus apella, based on phylogenetic analyses, pelage pattern and geographic provenance. One individual was identified as S. macrocephalus. We conclude that the point mutation C64T in the TYR gene is responsible for the OCA1 albino phenotype in the capuchin monkey, classified as Sapajus apella.

  5. Preparation of Au and Ag nanoparticles using Artemisia annua and their in vitro antibacterial and tyrosinase inhibitory activities

    International Nuclear Information System (INIS)

    Basavegowda, Nagaraj; Idhayadhulla, Akber; Lee, Yong Rok

    2014-01-01

    This work describes a plant-mediated approach to the preparation of metal nanoparticles using leaf extract of Artemisia annua (A. annua), an ethno-medicinal plant widely found in Asia, which was used as reducing and stabilizing agent. A. annua is used in traditional Chinese medicine to alleviate fever. Au and Ag nanoparticles were prepared using a one-step aqueous method at room temperature without any toxic chemicals. The formation of Au and Ag nanoparticles was monitored by UV–vis spectroscopy. Synthesized nanoparticles were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), energy dispersive X-ray analysis (EDX), Fourier transform infrared (FT-IR) spectroscopy, and thermogravimetric analysis (TGA). TEM analysis of Au nanoparticles showed that they had triangular and spherical shapes with sizes ranging from 15 to 40 nm. The silver nanoparticles were predominantly spherical and uniformly sized (30–50 nm). The Au and Ag nanoparticles produced showed significant tyrosinase inhibitory and antibacterial effects. These results suggest that the synthesized nanoparticles provide good alternatives in varied medical and industrial applications. - Highlights: • Au and Ag nanoparticles were synthesized using Artemisia annua leaf aqueous extract. • Nanoparticles were characterized by UV–vis spectroscopy, FT-IR, TEM, EDX, XRD, and TGA. • Au and Ag nanoparticles were of size 25 and 30 nm respectively, in spherical forms. • Nanoparticles showed significant tyrosinase inhibitory and antibacterial activities

  6. Amperometric Biosensor Based on Zirconium Oxide/Polyethylene Glycol/Tyrosinase Composite Film for the Detection of Phenolic Compounds

    Directory of Open Access Journals (Sweden)

    Nor Monica Ahmad

    2016-06-01

    Full Text Available A phenolic biosensor based on a zirconium oxide/polyethylene glycol/tyrosinase composite film for the detection of phenolic compounds has been explored. The formation of the composite film was expected via electrostatic interaction between hexacetyltrimethylammonium bromide (CTAB, polyethylene glycol (PEG, and zirconium oxide nanoparticles casted on screen printed carbon electrode (SPCE. Herein, the electrode was treated by casting hexacetyltrimethylammonium bromide on SPCE to promote a positively charged surface. Later, zirconium oxide was mixed with polyethylene glycol and the mixture was dropped cast onto the positively charged SPCE/CTAB. Tyrosinase was further immobilized onto the modified SPCE. Characterization of the prepared nanocomposite film and the modified SPCE surface was investigated by scanning electron microscopy (SEM, Electrochemical Impedance Spectroscopy (EIS, and Cyclic voltamogram (CV. The developed biosensor exhibits rapid response for less than 10 s. Two linear calibration curves towards phenol in the concentrations ranges of 0.075–10 µM and 10–55 µM with the detection limit of 0.034 µM were obtained. The biosensor shows high sensitivity and good storage stability for at least 30 days.

  7. The integration of cyanide hydratase and tyrosinase catalysts enables effective degradation of cyanide and phenol in coking wastewaters.

    Science.gov (United States)

    Martínková, Ludmila; Chmátal, Martin

    2016-10-01

    The aim of this study was to design an effective method for the bioremediation of coking wastewaters, specifically for the concurrent elimination of their highly toxic components - cyanide and phenols. Almost full degradation of free cyanide (0.32-20 mM; 8.3-520 mg L(-1)) in the model and the real coking wastewaters was achieved by using a recombinant cyanide hydratase in the first step. The removal of cyanide, a strong inhibitor of tyrosinase, enabled an effective degradation of phenols by this enzyme in the second step. Phenol (16.5 mM, 1,552 mg L(-1)) was completely removed from a real coking wastewater within 20 h and cresols (5.0 mM, 540 mg L(-1)) were removed by 66% under the same conditions. The integration of cyanide hydratase and tyrosinase open up new possibilities for the bioremediation of wastewaters with complex pollution. Copyright © 2016 Elsevier Ltd. All rights reserved.

  8. Influence of Laccase and Tyrosinase on the Antioxidant Capacity of Selected Phenolic Compounds on Human Cell Lines

    Directory of Open Access Journals (Sweden)

    Matthias Riebel

    2015-09-01

    Full Text Available Polyphenolic compounds affect the color, odor and taste of numerous food products of plant origin. In addition to the visual and gustatory properties, they serve as radical scavengers and have antioxidant effects. Polyphenols, especially resveratrol in red wine, have gained increasing scientific and public interest due to their presumptive beneficial impact on human health. Enzymatic oxidation of phenolic compounds takes place under the influence of polyphenol oxidases (PPO, including tyrosinase and laccase. Several studies have demonstrated the radical scavenger effect of plants, food products and individual polyphenols in vitro, but, apart from resveratrol, such impact has not been proved in physiological test systems. Furthermore, only a few data exist on the antioxidant capacities of the enzymatic oxidation products of phenolic compounds generated by PPO. We report here first results about the antioxidant effects of phenolic substances, before and after oxidation by fungal model tyrosinase and laccase. In general, the common chemical 2,2-diphenyl-1-picrylhydrazyl assay and the biological tests using two different types of cell cultures (monocytes and endothelial cells delivered similar results. The phenols tested showed significant differences with respect to their antioxidant activity in all test systems. Their antioxidant capacities after enzymatic conversion decreased or increased depending on the individual PPO used.

  9. Extracellular secretion of recombinant proteins

    Science.gov (United States)

    Linger, Jeffrey G.; Darzins, Aldis

    2014-07-22

    Nucleic acids encoding secretion signals, expression vectors containing the nucleic acids, and host cells containing the expression vectors are disclosed. Also disclosed are polypeptides that contain the secretion signals and methods of producing polypeptides, including methods of directing the extracellular secretion of the polypeptides. Exemplary embodiments include cellulase proteins fused to secretion signals, methods to produce and isolate these polypeptides, and methods to degrade lignocellulosic biomass.

  10. Stable convergence and stable limit theorems

    CERN Document Server

    Häusler, Erich

    2015-01-01

    The authors present a concise but complete exposition of the mathematical theory of stable convergence and give various applications in different areas of probability theory and mathematical statistics to illustrate the usefulness of this concept. Stable convergence holds in many limit theorems of probability theory and statistics – such as the classical central limit theorem – which are usually formulated in terms of convergence in distribution. Originated by Alfred Rényi, the notion of stable convergence is stronger than the classical weak convergence of probability measures. A variety of methods is described which can be used to establish this stronger stable convergence in many limit theorems which were originally formulated only in terms of weak convergence. Naturally, these stronger limit theorems have new and stronger consequences which should not be missed by neglecting the notion of stable convergence. The presentation will be accessible to researchers and advanced students at the master's level...

  11. The Potency of White Rice (Oryza sativa), Black Rice (Oryza sativa L. indica), and Red Rice (Oryza nivara) as Antioxidant and Tyrosinase Inhibitor

    Science.gov (United States)

    Batubara, I.; Maharni, M.; Sadiah, S.

    2017-04-01

    Rice is known to have many beneficial biological activities and is often used as “bedak dingin”, a face powder. The content of vitamins, minerals, fiber, and several types of antioxidants, such as ferulic acid, phytic acid, tocopherol, and oryzanols [1-2] are predicted to be potential as a tyrosinase inhibitor. The purpose of this study is to determine the potency of extracts from there types of rice, namely white, red, and black rice as an antioxidant and tyrosinase inhibitor. The rice was extracted with three different solvents, n-hexane, ethyl acetate, and methanol. The results showed that the highest antioxidant activity using 1,1-diphenyl-2-picrylhydrazyl method was found in the methanol extract of black rice (IC50 290 μg/mL). Meanwhile, ethyl acetate extract of white rice has the highest antioxidant activity withphosphomolybdic acid method (41 mmol α-tocopherol equivalents/g sample). Thus, methanol extract of black rice and ethyl acetate extract of white rice are potential as an antioxidant. For tyrosinase inhibitor, n-hexane extract of red rice (IC50 3156 μg/mL) was the most active extract. The active component for radical scavenging is polar compound and for antioxidant by phosphomolybdate method is less polar compounds in black rice methanol extract based on TLC bioautogram. In conclusion, the black rice is the most potent in antioxidant while red rice is for tyrosinase inhibition.

  12. Discovery of Highly Potent Tyrosinase Inhibitor, T1, with Significant Anti-Melanogenesis Ability by zebrafish in vivo Assay and Computational Molecular Modeling

    Science.gov (United States)

    Chen, Wang-Chuan; Tseng, Tien-Sheng; Hsiao, Nai-Wan; Lin, Yun-Lian; Wen, Zhi-Hong; Tsai, Chin-Chuan; Lee, Yu-Ching; Lin, Hui-Hsiung; Tsai, Keng-Chang

    2015-01-01

    Tyrosinase is involved in melanin biosynthesis and the abnormal accumulation of melanin pigments leading to hyperpigmentation disorders that can be treated with depigmenting agents. A natural product T1, bis(4-hydroxybenzyl)sulfide, isolated from the Chinese herbal plant, Gastrodia elata, is a strong competitive inhibitor against mushroom tyrosinase (IC50 = 0.53 μM, Ki = 58 +/- 6 nM), outperforms than kojic acid. The cell viability and melanin quantification assay demonstrate that 50 μM of T1 apparently attenuates 20% melanin content of human normal melanocytes without significant cell toxicity. Moreover, the zebrafish in vivo assay reveals that T1 effectively reduces melanogenesis with no adverse side effects. The acute oral toxicity study evidently confirms that T1 molecule is free of discernable cytotoxicity in mice. Furthermore, the molecular modeling demonstrates that the sulfur atom of T1 coordinating with the copper ions in the active site of tyrosinase is essential for mushroom tyrosinase inhibition and the ability of diminishing the human melanin synthesis. These results evident that T1 isolated from Gastrodia elata is a promising candidate in developing pharmacological and cosmetic agents of great potency in skin-whitening.

  13. Dual inhibition of γ-oryzanol on cellular melanogenesis: inhibition of tyrosinase activity and reduction of melanogenic gene expression by a protein kinase A-dependent mechanism.

    Science.gov (United States)

    Jun, Hee-jin; Lee, Ji Hae; Cho, Bo-Ram; Seo, Woo-Duck; Kang, Hang-Won; Kim, Dong-Woo; Cho, Kang-Jin; Lee, Sung-Joon

    2012-10-26

    The in vitro effects on melanogenesis of γ-oryzanol (1), a rice bran-derived phytosterol, were investigated. The melanin content in B16F1 cells was significantly and dose-dependently reduced (-13% and -28% at 3 and 30 μM, respectively). Tyrosinase enzyme activity was inhibited by 1 both in a cell-free assay and when analyzed based on the measurement of cellular tyrosinase activity. Transcriptome analysis was performed to investigate the biological pathways altered by 1, and it was found that gene expression involving protein kinase A (PKA) signaling was markedly altered. Subsequent analyses revealed that 1 stimulation in B16 cells reduced cytosolic cAMP concentrations, PKA activity (-13% for cAMP levels and -40% for PKA activity), and phosphorylation of the cAMP-response element binding protein (-57%), which, in turn, downregulated the expression of microphthalmia-associated transcription factor (MITF; -59% for mRNA and -64% for protein), a key melanogenic gene transcription factor. Accordingly, tyrosinase-related protein 1 (TRP-1; -69% for mRNA and -82% for protein) and dopachrome tautomerase (-51% for mRNA and -92% for protein) in 1-stimulated B16F1 cells were also downregulated. These results suggest that 1 has dual inhibitory activities for cellular melanogenesis by inhibiting tyrosinase enzyme activity and reducing MITF and target genes in the PKA-dependent pathway.

  14. Demonstration of tyrosinase in the vitiligo skin of human beings by a sensitive fluorometric method as well as by 14C(U)-L-tyrosine incorporation into melanin

    International Nuclear Information System (INIS)

    Husain, I.; Vijayan, E.; Ramaiah, A.; Pasricha, J.S.; Madan, N.C.

    1982-01-01

    Tyrosinase activity (Monophenol, dihydroxyphenylalanine: oxygen oxidoreductase EC 1.14.18.1) in vitiligo and normal epidermal homogenates of skin from human beings was measured by estimating beta 3,4-dihydroxyphenylalanine (dopa) by a highly sensitive fluorometric method described in this paper. The tyrosine activity in the vitiligo skin was about 4 to 37% of corresponding normal skin. The activity of tyrosinase in normal human skin from different individuals and from different regions of the body was in the range of 4 to 140 picomoles of beta 3,4-dihydroxyphenylalanine formed per min/mg protein of epidermal homogenate. The enzyme from vitiligo and normal skin was severely inhibited by substance(s) of low molecular weight. The enzyme exhibits a lag of about 4 hr in the absence of added beta 3,4-dihydroxyphenylalanine and 1 hr in presence of 5 microM dopa. Tyrosinase from the normal and vitiligo skin was inhibited by excess concentration of tyrosine. The homogenates from vitiligo skin could synthesize melanin from C14(U)-L-Tyrosine. The rate of tyrosine incorporation into melanin by the epidermal homogenates is increased by 3,4-dihydroxyphenylalanine (dopa) disproportionate to its effect on tyrosinase activity. Based on the data presented in this paper it is concluded that melanocytes are present in the vitiligo skin. A tentative hypothesis is put forward to explain the lack of melanin synthesis by the vitiligo skin under in vivo conditions, although melanocytes are present

  15. Limitations of the nested reverse transcriptase polymerase chain reaction on tyrosinase for the detection of malignant melanoma micrometastases in lymph nodes

    NARCIS (Netherlands)

    Calogero, A; Timmer-Bosscha, H; Tiebosch, ATMG; Mulder, NH; Hospers, GAP; Schraffordt Koops, H.

    The specificity and sensitivity of the nested reverse transcriptase polymerase chain reaction (RT-PCR) on tyrosinase was studied, for the detection of micrometastases of malignant melanoma. The specificity was assessed in the blood of six healthy donors, four patients with non-melanoma cancers of

  16. Validating tyrosinase homologue melA as a photoacoustic reporter gene for imaging Escherichia coli

    Science.gov (United States)

    Paproski, Robert J.; Li, Yan; Barber, Quinn; Lewis, John D.; Campbell, Robert E.; Zemp, Roger

    2015-10-01

    To understand the pathogenic processes for infectious bacteria, appropriate research tools are required for replicating and characterizing infections. Fluorescence and bioluminescence imaging have primarily been used to image infections in animal models, but optical scattering in tissue significantly limits imaging depth and resolution. Photoacoustic imaging, which has improved depth-to-resolution ratio compared to conventional optical imaging, could be useful for visualizing melA-expressing bacteria since melA is a bacterial tyrosinase homologue which produces melanin. Escherichia coli-expressing melA was visibly dark in liquid culture. When melA-expressing bacteria in tubes were imaged with a VisualSonics Vevo LAZR system, the signal-to-noise ratio of a 9× dilution sample was 55, suggesting that ˜20 bacteria cells could be detected with our system. Multispectral (680, 700, 750, 800, 850, and 900 nm) analysis of the photoacoustic signal allowed unmixing of melA-expressing bacteria from blood. To compare photoacoustic reporter gene melA (using Vevo system) with luminescent and fluorescent reporter gene Nano-lantern (using Bruker Xtreme In-Vivo system), tubes of bacteria expressing melA or Nano-lantern were submerged 10 mm in 1% Intralipid, spaced between melA-expressing bacteria even when the tubes were less than 1 mm from each other, while bioluminescence and fluorescence imaging could not resolve the two tubes of Nano-lantern-expressing bacteria even when the tubes were spaced 10 mm from each other. After injecting 100-μL of melA-expressing bacteria in the back flank of a chicken embryo, photoacoustic imaging allowed visualization of melA-expressing bacteria up to 10-mm deep into the embryo. Photoacoustic signal from melA could also be separated from deoxy- and oxy-hemoglobin signal observed within the embryo and chorioallantoic membrane. Our results suggest that melA is a useful photoacoustic reporter gene for visualizing bacteria, and further work

  17. Antioxidant activity and inhibitory effects of 2-hydroxy-3-methylcyclopent-2-enone isolated from ribose-histidine Maillard reaction products on aldose reductase and tyrosinase.

    Science.gov (United States)

    Hwang, Seung Hwan; Wang, Zhiqiang; Suh, Hong-Won; Lim, Soon Sung

    2018-03-01

    This study aimed to better understand the functional properties of ribose and 20 amino acid Maillard reaction products (MRPs). The ABTS + radical scavenging ability of the ribose-20 amino acid MRPs was evaluated. Among the MRPs, ribose-histidine MRPs (RH-MRPs) showed the highest inhibitory activities on the ABTS + radical scavenging ability, aldose reductase (AR), and tyrosinase compared to other MRPs. Functional compounds with antioxidant and AR inhibitory activities have been recognized as an important strategy in the prevention and treatment of diabetic complications, and the search for tyrosinase inhibitors is important for the treatment of hyperpigmentation, development of skin-whitening agents, and use as preservatives in the food industry. On this basis, we sought to isolate and identify compounds with inhibitory activities against AR and tyrosinase. RH-MRPs were heated at 120 °C for 2 h and fractionated using four solvents: methylene chloride (MC), ethyl acetate, n-butanol, and water. The highest inhibitions were found in the MC fraction. The two compounds from this fraction were purified by silica gel column and preparative thin layer chromatography, and identified as 2-hydroxy-3-methylcyclopent-2-enone and furan-3-carboxylic acid. AR inhibition, tyrosinase inhibition, and ABTS + scavenging (IC 50 ) of 2-hydroxy-3-methylcyclopent-2-enone were 4.47, 721.91 and 9.81 μg mL -1 , respectively. In this study, inhibitory effects of 2-hydroxy-3-methylcyclopent-2-enone isolated from RH-MRP were demonstrated on AR, tyrosinase, and its antioxidant activity for the first time. RH-MRP and its constituents can be developed as beneficial functional food sources and cosmetic materials and should be investigated further as potential functional food sources.

  18. Oxidant and solvent stable alkaline protease from Aspergillus flavus ...

    African Journals Online (AJOL)

    The increase in agricultural practices has necessitated the judicious use of agricultural wastes into value added products. In this study, an extracellular, organic solvent and oxidant stable, serine protease was produced by Aspergillus flavus MTCC 9952 under solid state fermentation. Maximum protease yield was obtained ...

  19. Chilean berry Ugni molinae Turcz. fruit and leaves extracts with interesting antioxidant, antimicrobial and tyrosinase inhibitory properties.

    Science.gov (United States)

    López de Dicastillo, Carol; Bustos, Fernanda; Valenzuela, Ximena; López-Carballo, Gracia; Vilariño, Jose M; Galotto, Maria Jose

    2017-12-01

    The knowledge of the biological properties of fruits and leaves of murta (Ugni molinae Turcz.) has been owned by native Chilean culture. The present study investigated the phenolic content, the antioxidant, antimicrobial and anti-tyrosinase activities of different murta fruit and leaves extracts to approach their uses on future food, pharmaceutical and cosmetic applications. Extractions of murta fruit and leaves were carried out under water, ethanol and ethanol 50%. Phenolic content of these extracts was measured through Folin Ciocalteu test and the antioxidant power by four different antioxidant systems (ORAC, FRAP, DPPH and TEAC assays) owing to elucidate the main mechanism of antioxidant. Some flavonoids, such as rutin, isoquercitrin and quercitrin hydrate were identified and quantified through HPLC analysis. Antimicrobial activity was determined measuring minimum inhibition concentration (MIC) and minimum bactericidal concentration (MBC) values against Escherichia coli and Listeria monocytogenes, and the effect of these extracts on L. monocytogenes was confirmed by flow cytometry. Highest contents of polyphenol compounds were obtained in hydroalcoholic extracts (28±1mggallicacid/g dry fruit, and 128±6mggallicacid/g dry leaves). The same trend was found for the values of biological properties: hydroalcoholic extracts showed the strongest activities. Leaves presented higher antioxidant, antimicrobial and anti-tyrosinase properties than murta fruit. Highest antioxidant activity values according to ORAC, FRAP, TEAC and DPPH were 80±8mgTrolox/g, 70±2mgTrolox/g, 87±8mgTrolox/g and 110±12mgTrolox/g, respectively, for murta fruit samples, and 280±10mgTrolox/g, 192±4mgTrolox/g, 286±13mgTrolox/g and 361±13mgTrolox/g, respectively, for murta leaves. These activities were confirmed by HPLC analysis that revealed highest presence of analyzed compounds on leaves hydroalcoholic extract. Regarding to antimicrobial analysis, hydroalcoholic leaves extract presented the

  20. stableGP

    Data.gov (United States)

    National Aeronautics and Space Administration — The code in the stableGP package implements Gaussian process calculations using efficient and numerically stable algorithms. Description of the algorithms is in the...

  1. Angina Pectoris (Stable Angina)

    Science.gov (United States)

    ... Peripheral Artery Disease Venous Thromboembolism Aortic Aneurysm More Angina Pectoris (Stable Angina) Updated:Aug 21,2017 You may have heard the term “angina pectoris” or “stable angina” in your doctor’s office, ...

  2. Extracellular Vesicles in Hematological Disorders

    Directory of Open Access Journals (Sweden)

    Anat Aharon

    2014-10-01

    Full Text Available Extracellular vesicles (EVs, comprised of exosomes, microparticles, apoptotic bodies, and other microvesicles, are shed from a variety of cells upon cell activation or apoptosis. EVs promote clot formation, mediate pro-inflammatory processes, transfer proteins and miRNA to cells, and induce cell signaling that regulates cell differentiation, proliferation, migration, invasion, and apoptosis. This paper will review the contribution of EVs in hematological disorders, including hemoglobinopathies (sickle cell disease, thalassemia, paroxysmal nocturnal hemoglobinuria, and hematological malignancies (lymphomas, myelomas, and acute and chronic leukemias.

  3. Blood extracellular DNA after irradiation

    International Nuclear Information System (INIS)

    Vladimirov, V.G.; Tishchenko, L.I.; Surkova, E.A.; Vasil'eva, I.N.

    1993-01-01

    It has been shown that blood extracellular DNA of irradiated rats largely consists of the low-molecular DNA and its oligomers. Molecular masses of oligomers are multiple to molecular mass of monomer fragment with nucleosome size. The low-molecular DNA has linear form. The average content of GC-pairs in low-molecular DNA is higher than in total rat's DNA (48.5% against 41.5%). The low-molecular DNA is a part of complex containing RNA, acidic proteins and lipids. It is assumed that the formation of low-molecular DNA is a result of Ca/Mg - dependent nuclear endonuclease action

  4. Extracellular nucleotide signaling in plants

    Energy Technology Data Exchange (ETDEWEB)

    Stacey, Gary [Univ. of Missouri, Columbia, MO (United States)

    2016-09-08

    Over the life of this funded project, our research group identified and characterized two key receptor proteins in plants; one mediating the innate immunity response to chitin and the other elucidating the key receptor for extracellular ATP. In the case of chitin recognition, we recently described the quaternary structure of this receptor, shedding light on how the receptor functions. Perhaps more importantly, we demonstrated that all plants have the ability to recognize both chitin oligomers and lipochitooligosacchardes, fundamentally changing how the community views the evolution of these systems and strategies that might be used, for example, to extend symbiotic nitrogen fixation to non-legumes. Our discovery of DORN1 opens a new chapter in plant physiology documenting conclusively that eATP is an important extracellular signal in plants, as it is in animals. At this point, we cannot predict just how far reaching this discovery may prove to be but we are convinced that eATP signaling is fundamental to plant growth and development and, hence, we believe that the future will be very exciting for the study of DORN1 and its overall function in plants.

  5. Determination of Patulin Using Amperometric Tyrosinase Biosensors Based on Electrodes Modified with Carbon Nanotubes and Gold Nanoparticles

    Directory of Open Access Journals (Sweden)

    R.M. Varlamova

    2016-06-01

    Full Text Available New amperometric biosensors based on platinum screen printed electrodes modified with multi-walled carbon nanotubes, gold nanoparticles, and immobilized enzyme – tyrosinase have been developed for determination of patulin in the concentrations of 1·10–6 – 8·10–12 mol/L with an error of no more than 0.063. The best conditions for obtaining gold nanoparticles have been chosen. The conditions for immobilization of multi-walled carbon nanotubes and gold nanoparticles on the surface of the planar electrode have been revealed. The conditions for functioning of the proposed biosensors have been identified. The results have been used to control the content of patulin in food products within and lower than the maximum allowable levels.

  6. SNPs in the 5'-regulatory region of the tyrosinase gene do not affect plumage color in ducks (Anas platyrhynchos).

    Science.gov (United States)

    Zhang, N N; Hu, J W; Liu, H H; Xu, H Y; He, H; Li, L

    2015-12-29

    Tyrosinase, encoded by the TYR gene, is the rate-limiting enzyme in the production of melanin pigment. In this study, plumage color separation was observed in Cherry Valley duck line D and F1 and F2 hybrid generations of Liancheng white ducks. Gene sequencing and bioinformatic analysis were applied to the 5'-regulatory region of TYR, to explore the connection between TYR sequence variation and duck plumage color. Four SNPs were found in the 5'-regulatory region. The SNPs were in tight linkage and formed three haplotypes. However, the genotype distribution in groups with different plumage color was not significantly different, and there were no changes in the transcription factor binding sites between the different genotypes. In conclusion, these SNP variations may not cause the differences in feather color observed in this test group.

  7. Single-step generation of rabbits carrying a targeted allele of the tyrosinase gene using CRISPR/Cas9.

    Science.gov (United States)

    Honda, Arata; Hirose, Michiko; Sankai, Tadashi; Yasmin, Lubna; Yuzawa, Kazuaki; Honsho, Kimiko; Izu, Haruna; Iguchi, Atsushi; Ikawa, Masahito; Ogura, Atsuo

    2015-01-01

    Targeted genome editing of nonrodent mammalian species has provided the potential for highly accurate interventions into gene function in humans and the generation of useful animal models of human diseases. Here we show successful clustered regularly interspaced short palindromic repeat (CRISPR) and CRISPR-associated (Cas)-mediated gene targeting via circular plasmid injection in rabbits. The rabbit tyrosinase gene (TYR) was effectively disrupted, and we confirmed germline transmission by pronuclear injection of a circular plasmid expressing humanized Cas9 (hCas9) and single-guide RNA. Direct injection into pronuclear stage zygotes was possible following an in vitro validation assay. Neither off-target mutagenesis nor hCas9 transgenesis was detected in any of the genetically targeted pups and embryos examined. Gene targeting with this rapid and simplified strategy will help accelerate the development of translational research using other nonrodent mammalian species.

  8. Increased therapeutic efficacy of a newly synthesized tyrosinase inhibitor by solid lipid nanoparticles in the topical treatment of hyperpigmentation

    Directory of Open Access Journals (Sweden)

    Al-Amin M

    2016-12-01

    Full Text Available Md Al-Amin, Jiafu Cao, Muhammad Naeem, Hasanul Banna, Min-Soo Kim, Yunjin Jung, Hae Young Chung, Hyung Ryong Moon, Jin-Wook Yoo College of Pharmacy, Pusan National University, Busan, South Korea Abstract: Hyperpigmentation caused by melanin overproduction is a major skin disorder in humans. Inhibition of tyrosinase, a key regulator of melanin production, has been used as an effective strategy to treat hyperpigmentation. In this study, we investigated the use of solid lipid nanoparticles (SLNs as a highly effective and nontoxic means to deliver a newly synthesized potent tyrosinase inhibitor, MHY498, and to target melanocytes through the skin. MHY498-loaded SLNs (MHY-SLNs were prepared by an oil-in-water emulsion solvent-evaporation method, and their morphological and physicochemical properties were characterized. MHY-SLNs showed a prolonged drug-release profile and higher skin permeation than that of MHY solution. In an in vivo evaluation of antimelanogenic activity, MHY-SLNs showed a prominent inhibitory effect against ultraviolet B-induced melanogenesis, resulting in no change in the skin color of C57BL/6 mouse, compared with that observed in an MHY solution-treated group and an untreated control group. The antimelanogenic effect of MHY-SLNs was further confirmed through Fontana–Masson staining. Importantly, MHY-SLNs did not induce any toxic effects in the L929 cell line. Overall, these data indicate that MHY-SLNs show promise in the topical treatment of hyperpigmentation. Keywords: melanogenesis, hyperpigmentation, MHY498, solid lipid nanoparticles, skin delivery

  9. Quercus infectoria and Terminalia chebula decrease melanin content and tyrosinase activity in B16/F10 cell lines

    Directory of Open Access Journals (Sweden)

    Akram Jamshidzadeh

    2017-10-01

    Full Text Available Context: One of the most complained skin cares in ethnic skin like Asian women is hyperpigmentation, and lightening preparations have been long-standing desired. Due to the side effects of current drugs, medicinal plants have attracted more attentions as a source of novel drugs. Mazo (Quercus infectoria galls and Terminalia chebula fruits have been suggested in Persian Traditional Medicine as a safe treatment for hyperpigmentation. Aims: To evaluate the cytotoxicity and the effect on melanin synthesis in B16/F10 melanoma of Q. infectoria and T. chebula extracts. Methods: After collection and scientific authentication, plants were extracted by maceration method with methanol and were standardized based on total phenolic content. MTT assay and colorimetric method were used for cytotoxicity and determination of melanin content and tyrosinase activity in B16/F10 cells, respectively. Kojic acid was used as a reference compound. Results: Total phenolic content of Q. infectoria and T. chebula was determined as 287.34 ± 4.21 and 172.61 ± 8.67 mg gallic acid equivalent/g dried extract, respectively. Both plants decreased cell viability at 100 µg/mL and significantly reduced intercellular melanin to 66.25% and 71.1%, respectively in comparison to kojic acid (56.63% at 50 µg/mL. In the same concentration, 65.7% and 71.2% tyrosinase activity was inhibited by Q. infectoria and T. chebula, which significantly were different from control (p<0.001. Conclusions: These findings suggest that both plants especially Q. infectoria could inhibit melanogenesis in non-toxic concentrations and would be a good candidate for further studies.

  10. Molecular docking studies of (1E,3E,5E)-1,6-Bis(substituted phenyl)hexa-1,3,5-triene and 1,4-Bis(substituted trans-styryl)benzene analogs as novel tyrosinase inhibitors.

    Science.gov (United States)

    Ha, Young Mi; Lee, Hye Jin; Park, Daeui; Jeong, Hyoung Oh; Park, Ji Young; Park, Yun Jung; Lee, Kyung Jin; Lee, Ji Yeon; Moon, Hyung Ryong; Chung, Hae Young

    2013-01-01

    We simulated the docking of the tertiary structure of mushroom tyrosinase with our compounds. From the structure-tyrosinase inhibitory activity relationship, it is notable that compounds 4, 8 and 11 showed similar or better activity rates than kojic acid which was used as a positive control. Compounds 17, 21, and 23 among benzene analogs that possess the same substituent showed significantly lower tyrosinase inhibitory effects. Therefore, we have confirmed that among the compounds showing better tyrosinase inhibitory effects than kojic acid, the compounds with triene analogs have better tyrosinase inhibitory effect than the compounds with benzene analogs. Docking simulation suggested the mechanism of compounds by several key residues which had possible hydrogen bonding interactions. The pharmacophore model underlined the features of active compounds, 4,4'-((1E,3E,5E)-hexa-1,3,5-triene-1,6-diyl)diphenol, 5,5'-((1E,3E,5E)-hexa-1,3,5-triene-1,6-diyl)bis(2-methoxy-phenol), and 5,5'-((1E,3E,5E)-hexa-1,3,5-triene-1,6-diyl)dibenzene-1,3-diol among triene derivatives which had several hydrogen bond groups on both terminal rings. The soundness of the docking results and the agreement with the pharmacophores suggest that it can be conveniently exploited to design inhibitors with an improved affinity for tyrosinase.

  11. Enhanced extracellular chitinase production in Pseudomonas fluorescens: biotechnological implications

    Directory of Open Access Journals (Sweden)

    Azhar Alhasawi

    2017-06-01

    Full Text Available Chitin is an important renewable biomass of immense commercial interest. The processing of this biopolymer into value-added products in an environmentally-friendly manner necessitates its conversion into N-acetyl glucosamine (NAG, a reaction mediated by the enzyme chitinase. Here we report on the ability of the soil microbe Pseudomonas fluorescens to secrete copious amounts of chitinase in the spent fluid when cultured in mineral medium with chitin as the sole source of carbon and nitrogen. Although chitinase was detected in various cellular fractions, the enzyme was predominantly localized in the extracellular component that was also rich in NAG and glucosamine. Maximal amounts of chitinase with a specific activity of 80 µmol NAG produced mg–1 protein min–1 was obtained at pH 8 after 6 days of growth in medium with 0.5 g of chitin. In-gel activity assays and Western blot studies revealed three isoenzymes. The enzyme had an optimal activity at pH 10 and a temperature range of 22–38 ℃. It was stable for up to 3 months. Although it showed optimal specificity toward chitin, the enzyme did readily degrade shrimp shells. When these shells (0.1 g were treated with the extracellular chitinase preparation, NAG [3 mmoles (0.003 g-mol] was generated in 6 h. The extracellular nature of the enzyme coupled with its physico-chemical properties make this chitinase an excellent candidate for biotechnological applications.

  12. Analysis of extracellular RNA by digital PCR

    Directory of Open Access Journals (Sweden)

    Kenji eTakahashi

    2014-06-01

    Full Text Available The transfer of extracellular RNA is emerging as an important mechanism for intracellular communication. The ability for the transfer of functionally active RNA molecules from one cell to another within vesicles such as exosomes enables a cell to modulate cellular signaling and biological processes within recipient cells. The study of extracellular RNA requires sensitive methods for the detection of these molecules. In this methods article, we will describe protocols for the detection of such extracellular RNA using sensitive detection technologies such as digital PCR. These protocols should be valuable to researchers interested in the role and contribution of extracellular RNA to tumor cell biology.

  13. Extracellular Molecules Involved in Cancer Cell Invasion

    International Nuclear Information System (INIS)

    Stivarou, Theodora; Patsavoudi, Evangelia

    2015-01-01

    Nowadays it is perfectly clear that understanding and eradicating cancer cell invasion and metastasis represent the crucial, definitive points in cancer therapeutics. During the last two decades there has been a great interest in the understanding of the extracellular molecular mechanisms involved in cancer cell invasion. In this review, we highlight the findings concerning these processes, focusing in particular on extracellular molecules, including extracellular matrix proteins and their receptors, growth factors and their receptors, matrix metalloproteinases and extracellular chaperones. We report the molecular mechanisms underlying the important contribution of this pool of molecules to the complex, multi-step phenomenon of cancer cell invasion

  14. Extracellular Molecules Involved in Cancer Cell Invasion

    Directory of Open Access Journals (Sweden)

    Theodora Stivarou

    2015-01-01

    Full Text Available Nowadays it is perfectly clear that understanding and eradicating cancer cell invasion and metastasis represent the crucial, definitive points in cancer therapeutics. During the last two decades there has been a great interest in the understanding of the extracellular molecular mechanisms involved in cancer cell invasion. In this review, we highlight the findings concerning these processes, focusing in particular on extracellular molecules, including extracellular matrix proteins and their receptors, growth factors and their receptors, matrix metalloproteinases and extracellular chaperones. We report the molecular mechanisms underlying the important contribution of this pool of molecules to the complex, multi-step phenomenon of cancer cell invasion.

  15. Stable Boundary Layer Issues

    OpenAIRE

    Steeneveld, G.J.

    2012-01-01

    Understanding and prediction of the stable atmospheric boundary layer is a challenging task. Many physical processes are relevant in the stable boundary layer, i.e. turbulence, radiation, land surface coupling, orographic turbulent and gravity wave drag, and land surface heterogeneity. The development of robust stable boundary layer parameterizations for use in NWP and climate models is hampered by the multiplicity of processes and their unknown interactions. As a result, these models suffer ...

  16. The International Society for Extracellular Vesicles launches the first massive open online course on extracellular vesicles

    OpenAIRE

    L?sser, Cecilia; Th?ry, Clotilde; Buz?s, Edit I.; Mathivanan, Suresh; Zhao, Weian; Gho, Yong Song; L?tvall, Jan

    2016-01-01

    The International Society for Extracellular Vesicles (ISEV) has organised its first educational online course for students and beginners in the field of extracellular vesicles (EVs). This course, “Basics of Extracellular Vesicles,” uses recorded lectures from experts in the field and will be open for an unlimited number of participants. The course is divided into 5 modules and can be accessed at www.coursera.org/learn/extracellular-vesicles. The first module is an introduction to the field co...

  17. Modulating effect of new potential antimelanomic agents, spin-labeled triazenes and nitrosoureas on the DOPA-oxidase activity of tyrosinase.

    Science.gov (United States)

    Gadjeva, V; Zheleva, A; Raikova, E

    1999-07-01

    The modulating effect of newly synthesized alkylating spin labeled triazene and spin labeled nitrosourea derivatives on the DOPA-oxidase activity of mushroom tyrosinase has been investigated by Bumett's spectrophotometric method (Burnett et al., 1967). All spin labeled triazenes have exhibited activating effect on DOPA-oxidase activity of tyrosinase, whereas clinically used triazene (DTIC), which does not contain nitroxide moiety, have showed inhibiting effect. At the same experimental conditions the spin labeled aminoacid nitrosoureas have showed dual effect - activating, in the beginning of the enzyme reaction and inhibiting later on. It is deduced that the activating effect of the spin labeled compounds is due to the nitroxide moiety and the inhibiting effect of all compounds depends on their half-life time. This study might contribute to make more clear the mechanism of action of the new compounds and on the other hand would come in quite useful as a preliminary prognosis for their antimelanomic activity.

  18. Evaluation of RPE65, CRALBP, VEGF, CD68, and tyrosinase gene expression in human retinal pigment epithelial cells cultured on amniotic membrane.

    Science.gov (United States)

    Akrami, Hassan; Soheili, Zahra-Soheila; Sadeghizadeh, Majid; Khalooghi, Keynoush; Ahmadieh, Hamid; Kanavi, Mojgan Rezaie; Samiei, Shahram; Pakravesh, Jalil

    2011-06-01

    The retinal pigment epithelium (RPE) plays a key role in the maintenance of the normal functions of the retina. Tissue engineering using amniotic membrane as a substrate to culture RPE cells may provide a promising new strategy to replace damaged RPE. We established a method of culturing RPE cells over the amniotic membrane as a support for their growth and transplantation. The transcription of specific genes involved in cellular function of native RPE, including RPE65, CRALBP, VEGF, CD68, and tyrosinase, were then measured using quantitative real-time PCR. Data showed a considerable increase in transcription of RPE65, CD68, and VEGF in RPE cells cultured on amniotic membrane. The amounts of CRALBP and tyrosinase transcripts were not affected. This may simply indicate that amniotic membrane restricted dedifferentiation of RPE cells in culture. The results suggest that amniotic membrane may be considered as an elective biological substrate for RPE cell culture.

  19. Characterization of inhibitory effects of the potential therapeutic inhibitors, benzoic acid and pyridine derivatives, on the monophenolase and diphenolase activities of tyrosinase.

    Science.gov (United States)

    Gheibi, Nematollah; Taherkhani, Negar; Ahmadi, Abolfazl; Haghbeen, Kamahldin; Ilghari, Dariush

    2015-02-01

    Involvement of tyrosinase in the synthesis of melanin and cell signaling pathway has made it an attractive target in the search for therapeutic inhibitors for treatment of different skin hyperpigmentation disorders and melanoma cancers. In the present study, we conducted a comprehensive kinetic analysis to understand the mechanisms of inhibition imposed by 2-amino benzoic acid, 4-amino benzoic acid, nicotinic acid, and picolinic acid on the monophenolase and diphenolase activities of the mushroom tyrosinase, and then MTT assay was exploited to evaluate their toxicity on the melanoma cells. Kinetic analysis revealed that nicotinic acid and picolinic acid competitively restricted the monophenolase activity with inhibition constants (Ki) of 1.21 mM and 1.97 mM and the diphenolase activity with Kis of 2.4 mM and 2.93 mM, respectively. 2-aminobenzoic acid and 4-aminobenzoic acid inhibited the monophenolase activity in a non-competitive fashion with Kis of 5.15 µM and 3.8 µM and the diphenolase activity with Kis of 4.72 µM and 20 µM, respectively. Our cell-based data revealed that only the pyridine derivatives imposed cytotoxicity in melanoma cells. Importantly, the concentrations of the inhibitors leading to 50% decrease in the cell density (IC50) were comparable to those causing 50% drop in the enzyme activity, implying that the observed cytotoxicity is highly likely due to the tyrosinase inhibition. Moreover, our cell-based data exhibited that the pyridine derivatives acted as anti-proliferative agents, perhaps inducing cytotoxicity in the melanoma cells through inhibition of the tyrosinase activities.

  20. Characterization of inhibitory effects of the potential therapeutic inhibitors, benzoic acid and pyridine derivatives, on the monophenolase and diphenolase activities of tyrosinase

    Directory of Open Access Journals (Sweden)

    Nematollah Gheibi

    2015-02-01

    Full Text Available Objective(s:Involvement of tyrosinase in the synthesis of melanin and cell signaling pathway has made it an attractive target in the search for therapeutic inhibitors for treatment of different skin hyperpigmentation disorders and melanoma cancers. Materials and Methods: In the present study, we conducted a comprehensive kinetic analysis to understand the mechanisms of inhibition imposed by 2-amino benzoic acid, 4-amino benzoic acid, nicotinic acid, and picolinic acid on the monophenolase and diphenolase activities of the mushroom tyrosinase, and then MTT assay was exploited to evaluate their toxicity on the melanoma cells. Results: Kinetic analysis revealed that nicotinic acid and picolinic acid competitively restricted the monophenolase activity with inhibition constants (Ki of 1.21 mM and 1.97 mM and the diphenolase activity with Kis of 2.4 mM and 2.93 mM, respectively. 2-aminobenzoic acid and 4-aminobenzoic acid inhibited the monophenolase activity in a non-competitive fashion with Kis of 5.15 µM and 3.8 µM and the diphenolase activity with Kis of 4.72 µM and 20 µM, respectively. Conclusion: Our cell-based data revealed that only the pyridine derivatives imposed cytotoxicity in melanoma cells. Importantly, the concentrations of the inhibitors leading to 50% decrease in the cell density (IC50 werecomparable to those causing 50% drop in the enzyme activity, implying that the observed cytotoxicity is highly likely due to the tyrosinase inhibition. Moreover, our cell-based data exhibited that the pyridine derivatives acted as anti-proliferative agents, perhaps inducing cytotoxicity in the melanoma cells through inhibition of the tyrosinase activities.

  1. Novel Hypomorphic Alleles of the Mouse Tyrosinase Gene Induced by CRISPR-Cas9 Nucleases Cause Non-Albino Pigmentation Phenotypes.

    Science.gov (United States)

    Challa, Anil K; Boitet, Evan R; Turner, Ashley N; Johnson, Larry W; Kennedy, Daniel; Downs, Ethan R; Hymel, Katherine M; Gross, Alecia K; Kesterson, Robert A

    2016-01-01

    Tyrosinase is a key enzyme in melanin biosynthesis. Mutations in the gene encoding tyrosinase (Tyr) cause oculocutaneous albinism (OCA1) in humans. Alleles of the Tyr gene have been useful in studying pigment biology and coat color formation. Over 100 different Tyr alleles have been reported in mice, of which ≈24% are spontaneous mutations, ≈60% are radiation-induced, and the remaining alleles were obtained by chemical mutagenesis and gene targeting. Therefore, most mutations were random and could not be predicted a priori. Using the CRISPR-Cas9 system, we targeted two distinct regions of exon 1 to induce pigmentation changes and used an in vivo visual phenotype along with heteroduplex mobility assays (HMA) as readouts of CRISPR-Cas9 activity. Most of the mutant alleles result in complete loss of tyrosinase activity leading to an albino phenotype. In this study, we describe two novel in-frame deletion alleles of Tyr, dhoosara (Sanskrit for gray) and chandana (Sanskrit for sandalwood). These alleles are hypomorphic and show lighter pigmentation phenotypes of the body and eyes. This study demonstrates the utility of CRISPR-Cas9 system in generating domain-specific in-frame deletions and helps gain further insights into structure-function of Tyr gene.

  2. Novel Hypomorphic Alleles of the Mouse Tyrosinase Gene Induced by CRISPR-Cas9 Nucleases Cause Non-Albino Pigmentation Phenotypes.

    Directory of Open Access Journals (Sweden)

    Anil K Challa

    Full Text Available Tyrosinase is a key enzyme in melanin biosynthesis. Mutations in the gene encoding tyrosinase (Tyr cause oculocutaneous albinism (OCA1 in humans. Alleles of the Tyr gene have been useful in studying pigment biology and coat color formation. Over 100 different Tyr alleles have been reported in mice, of which ≈24% are spontaneous mutations, ≈60% are radiation-induced, and the remaining alleles were obtained by chemical mutagenesis and gene targeting. Therefore, most mutations were random and could not be predicted a priori. Using the CRISPR-Cas9 system, we targeted two distinct regions of exon 1 to induce pigmentation changes and used an in vivo visual phenotype along with heteroduplex mobility assays (HMA as readouts of CRISPR-Cas9 activity. Most of the mutant alleles result in complete loss of tyrosinase activity leading to an albino phenotype. In this study, we describe two novel in-frame deletion alleles of Tyr, dhoosara (Sanskrit for gray and chandana (Sanskrit for sandalwood. These alleles are hypomorphic and show lighter pigmentation phenotypes of the body and eyes. This study demonstrates the utility of CRISPR-Cas9 system in generating domain-specific in-frame deletions and helps gain further insights into structure-function of Tyr gene.

  3. Stable isotopes labelled compounds

    International Nuclear Information System (INIS)

    1982-09-01

    The catalogue on stable isotopes labelled compounds offers deuterium, nitrogen-15, and multiply labelled compounds. It includes: (1) conditions of sale and delivery, (2) the application of stable isotopes, (3) technical information, (4) product specifications, and (5) the complete delivery programme

  4. Evolutionary Stable Strategy

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 21; Issue 9. Evolutionary Stable Strategy: Application of Nash Equilibrium in Biology. General Article Volume 21 Issue 9 September 2016 pp 803- ... Keywords. Evolutionary game theory, evolutionary stable state, conflict, cooperation, biological games.

  5. Stable Boundary Layer Issues

    NARCIS (Netherlands)

    Steeneveld, G.J.

    2012-01-01

    Understanding and prediction of the stable atmospheric boundary layer is a challenging task. Many physical processes are relevant in the stable boundary layer, i.e. turbulence, radiation, land surface coupling, orographic turbulent and gravity wave drag, and land surface heterogeneity. The

  6. Expression of human papilloma virus type 16 E5 protein in amelanotic melanoma cells regulates endo-cellular pH and restores tyrosinase activity

    Directory of Open Access Journals (Sweden)

    Coccia Raffaella

    2009-01-01

    Full Text Available Abstract Background Melanin synthesis, the elective trait of melanocytes, is regulated by tyrosinase activity. In tyrosinase-positive amelanotic melanomas this rate limiting enzyme is inactive because of acidic endo-melanosomal pH. The E5 oncogene of the Human Papillomavirus Type 16 is a small transmembrane protein with a weak transforming activity and a role during the early steps of viral infections. E5 has been shown to interact with 16 kDa subunit C of the trans-membrane Vacuolar ATPase proton pump ultimately resulting in its functional suppressions. However, the cellular effects of such an interaction are still under debate. With this work we intended to explore whether the HPV16 E5 oncoprotein does indeed interact with the vacuolar ATPase proton pump once expressed in intact human cells and whether this interaction has functional consequences on cell metabolism and phenotype. Methods The expression of the HPV16-E5 oncoproteins was induced in two Tyrosinase-positive amelanotic melanomas (the cell lines FRM and M14 by a retroviral expression construct. Modulation of the intracellular pH was measured with Acridine orange and fluorescence microscopy. Expression of tyrosinase and its activity was followed by RT-PCR, Western Blot and enzyme assay. The anchorage-independence growth and the metabolic activity of E5 expressing cells were also monitored. Results We provide evidence that in the E5 expressing cells interaction between E5 and V-ATPase determines an increase of endo-cellular pH. The cellular alkalinisation in turn leads to the post-translational activation of tyrosinase, melanin synthesis and phenotype modulation. These effects are associated with an increased activation of tyrosine analogue anti-blastic drugs. Conclusion Once expressed within intact human cells the HPV16-E5 oncoprotein does actually interact with the vacuolar V-ATPase proton pump and this interaction induces a number of functional effects. In amelanotic melanomas these

  7. Extracellular DNA metabolism in Haloferax volcanii

    Directory of Open Access Journals (Sweden)

    Scott eChimileski

    2014-02-01

    Full Text Available Extracellular DNA is found in all environments and is a dynamic component of the micro-bial ecosystem. Microbial cells produce and interact with extracellular DNA through many endogenous mechanisms. Extracellular DNA is processed and internalized for use as genetic information and as a major source of macronutrients, and plays several key roles within prokaryotic biofilms. Hypersaline sites contain some of the highest extracellular DNA con-centrations measured in nature–a potential rich source of carbon, nitrogen and phosphorus for halophilic microorganisms. We conducted DNA growth studies for the halophilic archaeon Haloferax volcanii DS2 and show that this model Halobacteriales strain is capable of using exogenous double-stranded DNA as a nutrient. Further experiments with varying medium composition, DNA concentration and DNA types revealed that DNA is utilized primarily as a phosphorus source, that growth on DNA is concentration-dependent and that DNA isolated from different sources is metabolized selectively, with a bias against highly divergent methylated DNA sources. Additionally, fluorescence microscopy experiments showed that labeled DNA colocalized with Haloferax volcanii cells. The gene Hvo_1477 was also identified using a comparative genomic approach as a factor likely to be involved in extracellular DNA processing at the cell surface, and deletion of Hvo_1477 created an H. volcanii strain deficient in its ability to grow on extracellular DNA. Widespread distribution of Hvo_1477 homologs in archaea suggests metabolism of extracellular DNA may be of broad ecological and physiological relevance in this domain of life.

  8. Normal modified stable processes

    DEFF Research Database (Denmark)

    Barndorff-Nielsen, Ole Eiler; Shephard, N.

    2002-01-01

    Gaussian (NGIG) laws. The wider framework thus established provides, in particular, for added flexibility in the modelling of the dynamics of financial time series, of importance especially as regards OU based stochastic volatility models for equities. In the special case of the tempered stable OU process......This paper discusses two classes of distributions, and stochastic processes derived from them: modified stable (MS) laws and normal modified stable (NMS) laws. This extends corresponding results for the generalised inverse Gaussian (GIG) and generalised hyperbolic (GH) or normal generalised inverse...

  9. Applications of stable isotopes

    International Nuclear Information System (INIS)

    Letolle, R.; Mariotti, A.; Bariac, T.

    1991-06-01

    This report reviews the historical background and the properties of stable isotopes, the methods used for their measurement (mass spectrometry and others), the present technics for isotope enrichment and separation, and at last the various present and foreseeable application (in nuclear energy, physical and chemical research, materials industry and research; tracing in industrial, medical and agronomical tests; the use of natural isotope variations for environmental studies, agronomy, natural resources appraising: water, minerals, energy). Some new possibilities in the use of stable isotope are offered. A last chapter gives the present state and forecast development of stable isotope uses in France and Europe

  10. Analysing Stable Time Series

    National Research Council Canada - National Science Library

    Adler, Robert

    1997-01-01

    We describe how to take a stable, ARMA, time series through the various stages of model identification, parameter estimation, and diagnostic checking, and accompany the discussion with a goodly number...

  11. Bacterial binding to extracellular proteins - in vitro adhesion

    DEFF Research Database (Denmark)

    Schou, C.; Fiehn, N.-E.

    1999-01-01

    Viridans streptococci, bacterial adherence, extracellular matrix proteins, surface receptors, endocarditis......Viridans streptococci, bacterial adherence, extracellular matrix proteins, surface receptors, endocarditis...

  12. A novel fluorescence biosensor for sensitivity detection of tyrosinase and acid phosphatase based on nitrogen-doped graphene quantum dots.

    Science.gov (United States)

    Qu, Zhengyi; Na, Weidan; Liu, Xiaotong; Liu, Hua; Su, Xingguang

    2018-01-02

    In this paper, we developed a sensitive fluorescence biosensor for tyrosinase (TYR) and acid phosphatase (ACP) activity detection based on nitrogen-doped graphene quantum dots (N-GQDs). Tyrosine could be catalyzed by TYR to generate dopaquinone, which could efficiently quench the fluorescence of N-GQDs, and the degree of fluorescence quenching of N-GQDs was proportional to the concentration of TYR. In the presence of ACP, l-Ascorbic acid-2-phosphate (AAP) was hydrolyzed to generate ascorbic acid (AA), and dopaquinone was reduced to l-dopa, resulting in the fluorescence recovery of the quenched fluorescence by dopaquinone. Thus, a novel fluorescence biosensor for the detection of TYR and ACP activity based on N-GQDs was constructed. Under the optimized experimental conditions, the fluorescence intensity was linearly correlated with the concentration of TYR and ACP in the range of 0.43-3.85 U mL -1 and 0.04-0.7 mU mL -1 with a detection limit of 0.15 U mL -1 and 0.014 mU mL -1 , respectively. The feasibility of the proposed biosensor in real samples assay was also studied and satisfactory results were obtained. Copyright © 2017 Elsevier B.V. All rights reserved.

  13. Identification of a missense mutation in the tyrosinase gene in a Chinese family with oculocutaneous albinism type 1.

    Science.gov (United States)

    Lu, Qian; Yuan, Lamei; Xu, Hongbo; Huang, Xiangjun; Yang, Zhijian; Yi, Junhui; Ni, Bin; Chen, Yong; Deng, Hao

    2017-03-01

    Oculocutaneous albinism (OCA) is a group of heterogeneous and autosomal recessive disorders characterized by a reduction or complete loss of melanin biosynthesis in melanocytes. OCA type 1 (OCA1) is the most severe and common form of OCA, and is caused by mutations in the tyrosinase gene (TYR). The present study aimed to identify the genetic cause of OCA1 in a four‑generation consanguineous Chinese Han family. Complete physical examinations were performed and blood samples were collected from five members of the family and 100 unrelated healthy controls. Exome sequencing was conducted in the proband, followed by verification in other family members, using Sanger sequencing. Patients in the family presented with typical OCA1 features, including hypopigmentation of the skin and hair, and distinctive ocular changes. A homozygous missense variant, c.896G>A (p.R299H), in the TYR gene was identified in two patients, which co‑segregated with disease in the family. This variant was not present in the 100 healthy controls. These results expand the number of mutations identified to be responsible for OCA1 in the Chinese Han population, and may have implications for genetic counseling and clinical management of the disease.

  14. Identification of c.483C>T polymorphism in the caprine tyrosinase-related protein 1 (TYRP1 gene

    Directory of Open Access Journals (Sweden)

    Bouabid Badaoui

    2012-03-01

    Full Text Available Tyrosinase-related protein 1 (TYRP1 has been shown to play a fundamental role in pigmentation both in human and mouse. In this work, we aimed to characterize the variability of the caprine TYRP1 gene and investigate its segregation in a wide array of goat breeds. By partially sequencing the coding region of the TYRP1 gene in 18 individuals from eight different breeds, we were able to identify a synonymous nucleotide substitution at exon 3 (c.483C>T. An extensive survey of Iberian and Balearic (N=175, Italian (N=99, Swiss (N=54, Asian (N=14, Canarian (N=92 and North African (N=117 goats with different coat colours was carried out. We found that the C-allele has a different distribution in European vs African breeds, being almost fixed in the latter. Moreover, the C-allele showed an increased frequency in white coated breeds (Girgentana, Grigia Molisana, Blanca de Rasquera and Saanen when compared with those displaying a dark pigmentation (Cilentana Nera, Azpi Gorri and Murciano- Granadina. This could be due to genetic drift, migration and other factors associated with the demographic history of breeds under analysis or to a genetic hitchhiking event (c.483C>T frequencies would be shaped by a neighbouring causal mutation differentially selected in white and black goats. More refined studies will be needed to distinguish between these two alternative explanations.

  15. Biosensor Based on Tyrosinase Immobilized on Graphene-Decorated Gold Nanoparticle/Chitosan for Phenolic Detection in Aqueous

    Directory of Open Access Journals (Sweden)

    Fuzi Mohamed Fartas

    2017-05-01

    Full Text Available In this research work, electrochemical biosensor was fabricated based on immobilization of tyrosinase onto graphene-decorated gold nanoparticle/chitosan (Gr-Au-Chit/Tyr nanocomposite-modified screen-printed carbon electrode (SPCE for the detection of phenolic compounds. The nanocomposite film was constructed via solution casting method. The electrocatalytic activity of the proposed biosensor for phenol detection was studied using differential pulse voltammetry (DPV and cyclic voltammetry (CV. Experimental parameters such as pH buffer, enzyme concentration, ratio of Gr-Au-Chit, accumulation time and potential were optimized. The biosensor shows linearity towards phenol in the concentration range from 0.05 to 15 μM with sensitivity of 0.624 μA/μM and the limit of detection (LOD of 0.016 μM (S/N = 3. The proposed sensor also depicts good reproducibility, selectivity and stability for at least one month. The biosensor was compared with high-performance liquid chromatography (HPLC method for the detection of phenol spiked in real water samples and the result is in good agreement and comparable.

  16. Identification of c.483C>T polymorphism in the caprine tyrosinase-related protein 1 (TYRP1 gene

    Directory of Open Access Journals (Sweden)

    Marcel Amills

    2012-01-01

    Full Text Available Tyrosinase-related protein 1 (TYRP1 has been shown to play a fundamental role in pigmentation both in human and mouse. In this work, we aimed to characterize the variability of the caprine TYRP1 gene and investigate its segregation in a wide array of goat breeds. By partially sequencing the coding region of the TYRP1 gene in 18 individuals from eight different breeds, we were able to identify a synonymous nucleotide substitution at exon 3 (c.483C>T. An extensive survey of Iberian and Balearic (N=175, Italian (N=99, Swiss (N=54, Asian (N=14, Canarian (N=92 and North African (N=117 goats with different coat colours was carried out. We found that the C-allele has a different distribution in European vs African breeds, being almost fixed in the latter. Moreover, the C-allele showed an increased frequency in white coated breeds (Girgentana, Grigia Molisana, Blanca de Rasquera and Saanen when compared with those displaying a dark pigmentation (Cilentana Nera, Azpi Gorri and Murciano- Granadina. This could be due to genetic drift, migration and other factors associated with the demographic history of breeds under analysis or to a genetic hitchhiking event (c.483C>T frequencies would be shaped by a neighbouring causal mutation differentially selected in white and black goats. More refined studies will be needed to distinguish between these two alternative explanations.

  17. Polyphenols Determination in Olive Oil Samples Based on a Thick Film Voltammetric Sensor and a Tyrosinase Biosensor

    Science.gov (United States)

    Capannesi, Cecilia; Palchetti, Ilaria; Mascini, Marco

    2000-12-01

    The aim of the present work was to compare different techniques to evaluate the variation with the storage time and storage conditions in the phenolic content of an extra-virgin olive oil. A disposable screen-printed sensor (SPE) was coupled with differential pulse voltammetry (DPV) to determine the phenolic fractions after extraction with glycine buffer; DPV parameters were chosen in order to study oxidation peak of oleuropein, that was used as reference compound. Moreover a tyrosinase based biosensor operating in organic solvent (hexane) was assembled, using an amperometric oxygen probe as transducer. Calibration curves were realised in flow injection analysis (F.I.A.) using phenol as substrate. Both of these methods are easy to operate, require no extraction (biosensor) or a rapid extraction procedure (SPE), and the analysis time is short (min.). The results obtained with these two innovative procedures were compared with classical spectrophotometric assay using the Folin-Ciocalteau reagent. Other extra-virgin olive oil quality parameters were investigated with classical methods in order to better define the alteration process and results are reported.

  18. Acetazolamide Inhibits the Level of Tyrosinase and Melanin: An Enzyme Kinetic, In Vitro, In Vivo, and In Silico Studies.

    Science.gov (United States)

    Abbas, Qamar; Raza, Hussain; Hassan, Mubashir; Phull, Abdul Rehman; Kim, Song Ja; Seo, Sung-Yum

    2017-09-01

    Melanin is the major factor that determines skin color and protects from ultraviolet radiation. In present study we evaluated the anti-melanogenesis effect of acetazolamide (ACZ) using four different approaches: enzyme kinetic, in vitro, in vivo and in silico. ACZ demonstrated significant inhibitory activity (IC 50 7.895 ± 0.24 μm) against tyrosinase as compared to the standard drug kojic acid (IC 50 16.84 ± 0.64 μm) and kinetic analyses showed that ACZ is a non-competitive inhibitor without cytotoxic effect. In in vitro experiments, A375 human melanoma cells were treated with 20 or 40 μm of ACZ with or without 50 μm of l-DOPA. Western blot results showed that ACZ significantly (P melanin and it could be used as a lead for developing the drugs for hyperpigmentary disorders and skin whitening. © 2017 Wiley-VHCA AG, Zurich, Switzerland.

  19. Self-assembled films containing crude extract of avocado as a source of tyrosinase for monophenol detection

    Energy Technology Data Exchange (ETDEWEB)

    Vieira, Nirton C.S., E-mail: nirtoncristi@gmail.com [Instituto de Física de São Carlos/Universidade de São Paulo, CP 369, 13560-970 São Carlos, SP (Brazil); Ferreira, Reginaldo A. [Centro de Estudos e Inovação em Materiais Biofuncionais Avançados/Universidade Federal de Itajubá, CP 50, 37500-903 Itajubá, MG (Brazil); Cruz Rodrigues, Valquiria da; Guimarães, Francisco E.G. [Instituto de Física de São Carlos/Universidade de São Paulo, CP 369, 13560-970 São Carlos, SP (Brazil); Queiroz, Alvaro A.A. de [Centro de Estudos e Inovação em Materiais Biofuncionais Avançados/Universidade Federal de Itajubá, CP 50, 37500-903 Itajubá, MG (Brazil)

    2013-10-15

    This paper reports on the use of the crude extract of avocado (CEA) fruit (Persea americana) as a source of tyrosinase enzyme. CEA was immobilized via layer by layer (LbL) technique onto indium tin oxide (ITO) substrates and applied in the detection of monophenol using a potentiometric biosensor. Poly(propylene imine) dendrimer of generation 3 (PPI-G3) was used as a counter ion in the layer by layer process due to its highly porous structure and functional groups suitable for enzyme linkage. After the immobilization of the crude CEA as multilayered films, standard samples of monophenol were detected in the 0.25–4.00 mM linear range with approximately 28 mV mM{sup −1} of sensitivity. This sensitivity is 14 times higher than the values found in the literature for a similar system. The results show that it is possible to obtain efficient and low-cost biosensors for monophenol detection using potentiometric transducers and alternative sources of enzymes without purification. - Highlights: • ITO films were functionalized with multilayers of PPI dendrimer and crude extract of avocado. • The films were applied as potentiometric biosensor for the detection of monophenol. • The proposed system presented an excellent sensitivity to monophenol (27 mV mM{sup −1})

  20. Self-assembled films containing crude extract of avocado as a source of tyrosinase for monophenol detection

    International Nuclear Information System (INIS)

    Vieira, Nirton C.S.; Ferreira, Reginaldo A.; Cruz Rodrigues, Valquiria da; Guimarães, Francisco E.G.; Queiroz, Alvaro A.A. de

    2013-01-01

    This paper reports on the use of the crude extract of avocado (CEA) fruit (Persea americana) as a source of tyrosinase enzyme. CEA was immobilized via layer by layer (LbL) technique onto indium tin oxide (ITO) substrates and applied in the detection of monophenol using a potentiometric biosensor. Poly(propylene imine) dendrimer of generation 3 (PPI-G3) was used as a counter ion in the layer by layer process due to its highly porous structure and functional groups suitable for enzyme linkage. After the immobilization of the crude CEA as multilayered films, standard samples of monophenol were detected in the 0.25–4.00 mM linear range with approximately 28 mV mM −1 of sensitivity. This sensitivity is 14 times higher than the values found in the literature for a similar system. The results show that it is possible to obtain efficient and low-cost biosensors for monophenol detection using potentiometric transducers and alternative sources of enzymes without purification. - Highlights: • ITO films were functionalized with multilayers of PPI dendrimer and crude extract of avocado. • The films were applied as potentiometric biosensor for the detection of monophenol. • The proposed system presented an excellent sensitivity to monophenol (27 mV mM −1 )

  1. The Investigation of Electrochemistry Behaviors of Tyrosinase Based on Directly-Electrodeposited Grapheneon Choline-Gold Nanoparticles.

    Science.gov (United States)

    He, Yaping; Yang, Xiaohui; Han, Quan; Zheng, Jianbin

    2017-06-23

    A novel catechol (CA) biosensor was developed by embedding tyrosinase (Tyr) onto in situ electrochemical reduction graphene (EGR) on choline-functionalized gold nanoparticle (AuNPs-Ch) film. The results of UV-Vis spectra indicated that Tyr retained its original structure in the film, and an electrochemical investigation of the biosensor showed a pair of well-defined, quasi-reversible redox peaks with E pa = -0.0744 V and E pc = -0.114 V (vs. SCE) in 0.1 M, pH 7.0 sodium phosphate-buffered saline at a scan rate of 100 mV/s. The transfer rate constant k s is 0.66 s -1 . The Tyr-EGR/AuNPs-Ch showed a good electrochemical catalytic response for the reduction of CA, with the linear range from 0.2 to 270 μM and a detection limit of 0.1 μM (S/N = 3). The apparent Michaelis-Menten constant was estimated to be 109 μM.

  2. Detection of extracellular enzymatic activity in microorganisms ...

    African Journals Online (AJOL)

    Detection of extracellular enzymatic activity in microorganisms isolated from waste vegetable oil contaminated soil using plate methodologies. Eugenia G. Ortiz Lechuga, Isela Quintero Zapata, Katiushka Arévalo Niño ...

  3. Purification and characterization of extracellular amylolytic enzyme ...

    African Journals Online (AJOL)

    DOSS

    2012-10-16

    Oct 16, 2012 ... Available online at http://www.academicjournals.org/AJB ... characterization of extracellular amylases from four ... Somogyi-Nelson's method (Nelson, 1944; Somogyi, 1952). ... The mycelia dry weight of currently studied four.

  4. Neutrophil Extracellular Traps in Ulcerative Colitis

    DEFF Research Database (Denmark)

    Bjerg Bennike, Tue; Carlsen, Thomas Gelsing; Ellingsen, Torkell

    2015-01-01

    microscopy and confocal microscopy. RESULTS: We identified and quantified 5711 different proteins with proteomics. The abundance of the proteins calprotectin and lactotransferrin in the tissue correlated with the degree of tissue inflammation as determined by histology. However, fecal calprotectin did...... not correlate. Forty-six proteins were measured with a statistically significant differences in abundances between the UC colon tissue and controls. Eleven of the proteins with increased abundances in the UC biopsies were associated with neutrophils and neutrophil extracellular traps. The findings were...... validated by microscopy, where an increased abundance of neutrophils and the presence of neutrophil extracellular traps by extracellular DNA present in the UC colon tissue were confirmed. CONCLUSIONS: Neutrophils, induced neutrophil extracellular traps, and several proteins that play a part in innate...

  5. Sources of extracellular tau and its signaling.

    Science.gov (United States)

    Avila, Jesús; Simón, Diana; Díaz-Hernández, Miguel; Pintor, Jesús; Hernández, Félix

    2014-01-01

    The pathology associated with tau protein, tauopathy, has been recently analyzed in different disorders, leading to the suggestion that intracellular and extracellular tau may itself be the principal agent in the transmission and spreading of tauopathies. Tau pathology is based on an increase in the amount of tau, an increase in phosphorylated tau, and/or an increase in aggregated tau. Indeed, phosphorylated tau protein is the main component of tau aggregates, such as the neurofibrillary tangles present in the brain of Alzheimer's disease patients. It has been suggested that intracellular tau could be toxic to neurons in its phosphorylated and/or aggregated form. However, extracellular tau could also damage neurons and since neuronal death is widespread in Alzheimer's disease, mainly among cholinergic neurons, these cells may represent a possible source of extracellular tau. However, other sources of extracellular tau have been proposed that are independent of cell death. In addition, several ways have been proposed for cells to interact with, transmit, and spread extracellular tau, and to transduce signals mediated by this tau. In this work, we will discuss the role of extracellular tau in the spreading of the tau pathology.

  6. Transcriptome of extracellular vesicles released by hepatocytes.

    Directory of Open Access Journals (Sweden)

    Felix Royo

    Full Text Available The discovery that the cells communicate through emission of vesicles has opened new opportunities for better understanding of physiological and pathological mechanisms. This discovery also provides a novel source for non-invasive disease biomarker research. Our group has previously reported that hepatocytes release extracellular vesicles with protein content reflecting the cell-type of origin. Here, we show that the extracellular vesicles released by hepatocytes also carry RNA. We report the messenger RNA composition of extracellular vesicles released in two non-tumoral hepatic models: primary culture of rat hepatocytes and a progenitor cell line obtained from a mouse foetal liver. We describe different subpopulations of extracellular vesicles with different densities and protein and RNA content. We also show that the RNA cargo of extracellular vesicles released by primary hepatocytes can be transferred to rat liver stellate-like cells and promote their activation. Finally, we provide in vitro and in vivo evidence that liver-damaging drugs galactosamine, acetaminophen, and diclofenac modify the RNA content of these vesicles. To summarize, we show that the extracellular vesicles secreted by hepatocytes contain various RNAs. These vesicles, likely to be involved in the activation of stellate cells, might become a new source for non-invasive identification of the liver toxicity markers.

  7. Glioblastoma extracellular vesicles: reservoirs of potential biomarkers

    Directory of Open Access Journals (Sweden)

    Redzic JS

    2014-02-01

    Full Text Available Jasmina S Redzic,1 Timothy H Ung,2 Michael W Graner2 1Skaggs School of Pharmacy and Pharmaceutical Sciences, 2Department of Neurosurgery, School of Medicine, University of Colorado Denver, Aurora, CO, USA Abstract: Glioblastoma multiforme (GBM is the most frequent and most devastating of the primary central nervous system tumors, with few patients living beyond 2 years postdiagnosis. The damage caused by the disease and our treatments for the patients often leave them physically and cognitively debilitated. Generally, GBMs appear after very short clinical histories and are discovered by imaging (using magnetic resonance imaging [MRI], and the diagnosis is validated by pathology, following surgical resection. The treatment response and diagnosis of tumor recurrence are also tracked by MRI, but there are numerous problems encountered with these monitoring modalities, such as ambiguous interpretation and forms of pseudoprogression. Diagnostic, prognostic, and predictive biomarkers would be an immense boon in following treatment schemes and in determining recurrence, which often requires an invasive intracranial biopsy to verify imaging data. Extracellular vesicles (EVs are stable, membrane-enclosed, virus-sized particles released from either the cell surface or from endosomal pathways that lead to the systemic release of EVs into accessible biofluids, such as serum/plasma, urine, cerebrospinal fluid, and saliva. EVs carry a wide variety of proteins, nucleic acids, lipids, and other metabolites, with many common features but with enough individuality to be able to identify the cell of origin of the vesicles. These components, if properly interrogated, could allow for the identification of tumor-derived EVs in biofluids, indicating tumor progression, relapse, or treatment failure. That knowledge would allow clinicians to continue with treatment regimens that were actually effective or to change course if the therapies were failing. Here, we review

  8. Uses of stable isotopes

    International Nuclear Information System (INIS)

    Axente, Damian

    1998-01-01

    The most important fields of stable isotope use with examples are presented. These are: 1. Isotope dilution analysis: trace analysis, measurements of volumes and masses; 2. Stable isotopes as tracers: transport phenomena, environmental studies, agricultural research, authentication of products and objects, archaeometry, studies of reaction mechanisms, structure and function determination of complex biological entities, studies of metabolism, breath test for diagnostic; 3. Isotope equilibrium effects: measurement of equilibrium effects, investigation of equilibrium conditions, mechanism of drug action, study of natural processes, water cycle, temperature measurements; 4. Stable isotope for advanced nuclear reactors: uranium nitride with 15 N as nuclear fuel, 157 Gd for reactor control. In spite of some difficulties of stable isotope use, particularly related to the analytical techniques, which are slow and expensive, the number of papers reporting on this subject is steadily growing as well as the number of scientific meetings organized by International Isotope Section and IAEA, Gordon Conferences, and regional meeting in Germany, France, etc. Stable isotope application development on large scale is determined by improving their production technologies as well as those of labeled compound and the analytical techniques. (author)

  9. Wetting and dewetting of extracellular matrix and glycocalix models

    International Nuclear Information System (INIS)

    Tanaka, Motomu; Rehfeldt, Florian; Schneider, Matthias F; Mathe, Gerald; Albersdoerfer, Antero; Neumaier, Klaus R; Purrucker, Oliver; Sackmann, Erich

    2005-01-01

    In this paper, we study wetting and dewetting of hydrated biopolymer layers mediating cell-cell and cell-tissue contacts, called the extracellular matrix and cell surface glycocalix, by the combination of various physical techniques. Here, the sum of the net effects of the various interfacial forces, which is referred to as the disjoining pressure, is used as a semi-quantitative measure to describe the thermodynamics of hydrated interlayers. The disjoining pressure can be measured by applying external forces to maintain the equilibrium distance between two parallel surfaces (in biology, two neighbouring plasma membranes). Using artificial models of the extracellular matrix and glycocalix, we describe stable cell-cell contacts in terms of the wetting (or spreading) of complex fluids on polymer surfaces. In fact, the adjustment of the wetting interaction via thin hydrating layers enables us to transform three-dimensional cell membranes into quasi-two-dimensional films on macroscopically large surfaces. Fine-tuning of local wetting conditions at the interface further allows for the selective wetting of native cell membranes on microstructured polysaccharide films, which has a large potential for individual detection of biological functions in confined geometries

  10. Calcium stable isotope geochemistry

    Energy Technology Data Exchange (ETDEWEB)

    Gausonne, Nikolaus [Muenster Univ. (Germany). Inst. fuer Mineralogie; Schmitt, Anne-Desiree [Strasbourg Univ. (France). LHyGeS/EOST; Heuser, Alexander [Bonn Univ. (Germany). Steinmann-Inst. fuer Geologie, Mineralogie und Palaeontologie; Wombacher, Frank [Koeln Univ. (Germany). Inst. fuer Geologie und Mineralogie; Dietzel, Martin [Technische Univ. Graz (Austria). Inst. fuer Angewandte Geowissenschaften; Tipper, Edward [Cambridge Univ. (United Kingdom). Dept. of Earth Sciences; Schiller, Martin [Copenhagen Univ. (Denmark). Natural History Museum of Denmark

    2016-08-01

    This book provides an overview of the fundamentals and reference values for Ca stable isotope research, as well as current analytical methodologies including detailed instructions for sample preparation and isotope analysis. As such, it introduces readers to the different fields of application, including low-temperature mineral precipitation and biomineralisation, Earth surface processes and global cycling, high-temperature processes and cosmochemistry, and lastly human studies and biomedical applications. The current state of the art in these major areas is discussed, and open questions and possible future directions are identified. In terms of its depth and coverage, the current work extends and complements the previous reviews of Ca stable isotope geochemistry, addressing the needs of graduate students and advanced researchers who want to familiarize themselves with Ca stable isotope research.

  11. Calcium stable isotope geochemistry

    International Nuclear Information System (INIS)

    Gausonne, Nikolaus; Schmitt, Anne-Desiree; Heuser, Alexander; Wombacher, Frank; Dietzel, Martin; Tipper, Edward; Schiller, Martin

    2016-01-01

    This book provides an overview of the fundamentals and reference values for Ca stable isotope research, as well as current analytical methodologies including detailed instructions for sample preparation and isotope analysis. As such, it introduces readers to the different fields of application, including low-temperature mineral precipitation and biomineralisation, Earth surface processes and global cycling, high-temperature processes and cosmochemistry, and lastly human studies and biomedical applications. The current state of the art in these major areas is discussed, and open questions and possible future directions are identified. In terms of its depth and coverage, the current work extends and complements the previous reviews of Ca stable isotope geochemistry, addressing the needs of graduate students and advanced researchers who want to familiarize themselves with Ca stable isotope research.

  12. Stable isotope studies

    International Nuclear Information System (INIS)

    Ishida, T.

    1992-01-01

    The research has been in four general areas: (1) correlation of isotope effects with molecular forces and molecular structures, (2) correlation of zero-point energy and its isotope effects with molecular structure and molecular forces, (3) vapor pressure isotope effects, and (4) fractionation of stable isotopes. 73 refs, 38 figs, 29 tabs

  13. Interactive Stable Ray Tracing

    DEFF Research Database (Denmark)

    Dal Corso, Alessandro; Salvi, Marco; Kolb, Craig

    2017-01-01

    Interactive ray tracing applications running on commodity hardware can suffer from objectionable temporal artifacts due to a low sample count. We introduce stable ray tracing, a technique that improves temporal stability without the over-blurring and ghosting artifacts typical of temporal post-pr...

  14. The Stable Concordance Genus

    OpenAIRE

    Kearney, M. Kate

    2013-01-01

    The concordance genus of a knot is the least genus of any knot in its concordance class. Although difficult to compute, it is a useful invariant that highlights the distinction between the three-genus and four-genus. In this paper we define and discuss the stable concordance genus of a knot, which describes the behavior of the concordance genus under connected sum.

  15. Stable radiographic scanning agents

    International Nuclear Information System (INIS)

    1976-01-01

    Stable compositions which are useful in the preparation of Technetium-99m-based scintigraphic agents are discussed. They are comprised of ascorbic acid or a pharmaceutically acceptable salt or ester thereof in combination with a pertechnetate reducing agent or dissolved in oxidized pertechnetate-99m (sup(99m)TcO 4 - ) solution

  16. Some stable hydromagnetic equilibria

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, J L; Oberman, C R; Kulsrud, R M; Frieman, E A [Project Matterhorn, Princeton University, Princeton, NJ (United States)

    1958-07-01

    We have been able to find and investigate the properties of equilibria which are hydromagnetically stable. These equilibria can be obtained, for example, by wrapping conductors helically around the stellarator tube. Systems with I = 3 or 4 are indicated to be optimum for stability purposes. In some cases an admixture of I = 2 fields can be advantageous for achieving equilibrium. (author)

  17. Assessment of extracellular dehydration using saliva osmolality.

    Science.gov (United States)

    Ely, Brett R; Cheuvront, Samuel N; Kenefick, Robert W; Spitz, Marissa G; Heavens, Kristen R; Walsh, Neil P; Sawka, Michael N

    2014-01-01

    When substantial solute losses accompany body water an isotonic hypovolemia (extracellular dehydration) results. The potential for using blood or urine to assess extracellular dehydration is generally poor, but saliva is not a simple ultra-filtrate of plasma and the autonomic regulation of salivary gland function suggests the possibility that saliva osmolality (Sosm) may afford detection of extracellular dehydration via the influence of volume-mediated factors. This study aimed to evaluate the assessment of extracellular dehydration using Sosm. In addition, two common saliva collection methods and their effects on Sosm were compared. Blood, urine, and saliva samples were collected in 24 healthy volunteers during paired euhydration and dehydration trials. Furosemide administration and 12 h fluid restriction were used to produce extracellular dehydration. Expectoration and salivette collection methods were compared in a separate group of eight euhydrated volunteers. All comparisons were made using paired t-tests. The diagnostic potential of body fluids was additionally evaluated. Dehydration (3.1 ± 0.5% loss of body mass) decreased PV (-0.49 ± 0.12 L; -15.12 ± 3.94% change), but Sosm changes were marginal ( 0.05). Extracelluar dehydration was not detectable using plasma, urine, or saliva measures. Salivette and expectoration sampling methods produced similar, consistent results for Sosm, suggesting no methodological influence on Sosm.

  18. Extracellular histones in tissue injury and inflammation.

    Science.gov (United States)

    Allam, Ramanjaneyulu; Kumar, Santhosh V R; Darisipudi, Murthy N; Anders, Hans-Joachim

    2014-05-01

    Neutrophil NETosis is an important element of host defense as it catapults chromatin out of the cell to trap bacteria, which then are killed, e.g., by the chromatin's histone component. Also, during sterile inflammation TNF-alpha and other mediators trigger NETosis, which elicits cytotoxic effects on host cells. The same mechanism should apply to other forms of regulated necrosis including pyroptosis, necroptosis, ferroptosis, and cyclophilin D-mediated regulated necrosis. Beyond these toxic effects, extracellular histones also trigger thrombus formation and innate immunity by activating Toll-like receptors and the NLRP3 inflammasome. Thereby, extracellular histones contribute to the microvascular complications of sepsis, major trauma, small vessel vasculitis as well as acute liver, kidney, brain, and lung injury. Finally, histones prevent the degradation of extracellular DNA, which promotes autoimmunization, anti-nuclear antibody formation, and autoimmunity in susceptible individuals. Here, we review the current evidence on the pathogenic role of extracellular histones in disease and discuss how to target extracellular histones to improve disease outcomes.

  19. Circulating Tyrosinase and MART-1 mRNA does not Independently Predict Relapse or Survival in Patients with AJCC Stage I–II Melanoma

    DEFF Research Database (Denmark)

    Schmidt, Henrik; Sørensen, Boe S; Sjoegren, Pia

    2006-01-01

    The detection of melanoma cells in peripheral blood has been proposed to select patients with a high risk of relapse. In this study, tyrosinase and melanoma antigen recognized by T cells 1 (MART-1) mRNA expression was evaluated in serial samples obtained before definitive surgery and during follow......-up in patients with American Joint Committee on Cancer stage I-II melanoma. Serial samples (n=2,262) were collected from 236 patients from 1997 to 2002. Analyses of the RNA samples were performed with a calibrated reverse transcriptase-PCR assay. Gender, age, primary tumor site, ulceration, thickness, Clark...

  20. Shaping Synapses by the Neural Extracellular Matrix

    Directory of Open Access Journals (Sweden)

    Maura Ferrer-Ferrer

    2018-05-01

    Full Text Available Accumulating data support the importance of interactions between pre- and postsynaptic neuronal elements with astroglial processes and extracellular matrix (ECM for formation and plasticity of chemical synapses, and thus validate the concept of a tetrapartite synapse. Here we outline the major mechanisms driving: (i synaptogenesis by secreted extracellular scaffolding molecules, like thrombospondins (TSPs, neuronal pentraxins (NPs and cerebellins, which respectively promote presynaptic, postsynaptic differentiation or both; (ii maturation of synapses via reelin and integrin ligands-mediated signaling; and (iii regulation of synaptic plasticity by ECM-dependent control of induction and consolidation of new synaptic configurations. Particularly, we focused on potential importance of activity-dependent concerted activation of multiple extracellular proteases, such as ADAMTS4/5/15, MMP9 and neurotrypsin, for permissive and instructive events in synaptic remodeling through localized degradation of perisynaptic ECM and generation of proteolytic fragments as inducers of synaptic plasticity.

  1. Extracellular enzyme kinetics scale with resource availability

    Science.gov (United States)

    Sinsabaugh, Robert L.; Belnap, Jayne; Findlay, Stuart G.; Follstad Shah, Jennifer J.; Hill, Brian H.; Kuehn, Kevin A.; Kuske, Cheryl; Litvak, Marcy E.; Martinez, Noelle G.; Moorhead, Daryl L.; Warnock, Daniel D.

    2014-01-01

    Microbial community metabolism relies on external digestion, mediated by extracellular enzymes that break down complex organic matter into molecules small enough for cells to assimilate. We analyzed the kinetics of 40 extracellular enzymes that mediate the degradation and assimilation of carbon, nitrogen and phosphorus by diverse aquatic and terrestrial microbial communities (1160 cases). Regression analyses were conducted by habitat (aquatic and terrestrial), enzyme class (hydrolases and oxidoreductases) and assay methodology (low affinity and high affinity substrates) to relate potential reaction rates to substrate availability. Across enzyme classes and habitats, the scaling relationships between apparent Vmax and apparent Km followed similar power laws with exponents of 0.44 to 0.67. These exponents, called elasticities, were not statistically distinct from a central value of 0.50, which occurs when the Km of an enzyme equals substrate concentration, a condition optimal for maintenance of steady state. We also conducted an ecosystem scale analysis of ten extracellular hydrolase activities in relation to soil and sediment organic carbon (2,000–5,000 cases/enzyme) that yielded elasticities near 1.0 (0.9 ± 0.2, n = 36). At the metabolomic scale, the elasticity of extracellular enzymatic reactions is the proportionality constant that connects the C:N:P stoichiometries of organic matter and ecoenzymatic activities. At the ecosystem scale, the elasticity of extracellular enzymatic reactions shows that organic matter ultimately limits effective enzyme binding sites. Our findings suggest that one mechanism by which microbial communities maintain homeostasis is regulating extracellular enzyme expression to optimize the short-term responsiveness of substrate acquisition. The analyses also show that, like elemental stoichiometry, the fundamental attributes of enzymatic reactions can be extrapolated from biochemical to community and ecosystem scales.

  2. MR imaging of intracellular and extracellular deoxyhemoglobin

    International Nuclear Information System (INIS)

    Janick, P.A.; Grossman, R.I.; Asakura, T.

    1989-01-01

    MR imaging was performed on varying concentrations of intracellular and extracellular deoxyhemoglobin as well as varying proportions of deoxyhemoglobin and oxyhemoglobin in vitro at 1.5T with use of standard spin-echo and gradient-refocused spin sequences. This study indicates that susceptibility-induced T2 shortening occurs over a broad range of intracellular deoxyhemoglobin concentrations (maximal at hematocrits between 20% and 45%), reflecting diffusional effects at the cellular level. T2* gradient-echo imaging enhances the observed hypointensity in images of intracellular deoxyhemoglobin. The characteristic MR appearance of acute hemotomas can be modeled by the behavior of intracellular and extracellular deoxyhemoglobin and oxyhemoglobin

  3. Stable isotope analysis

    International Nuclear Information System (INIS)

    Tibari, Elghali; Taous, Fouad; Marah, Hamid

    2014-01-01

    This report presents results related to stable isotopes analysis carried out at the CNESTEN DASTE in Rabat (Morocco), on behalf of Senegal. These analyzes cover 127 samples. These results demonstrate that Oxygen-18 and Deuterium in water analysis were performed by infrared Laser spectroscopy using a LGR / DLT-100 with Autosampler. Also, the results are expressed in δ values (‰) relative to V-SMOW to ± 0.3 ‰ for oxygen-18 and ± 1 ‰ for deuterium.

  4. Forensic Stable Isotope Biogeochemistry

    Science.gov (United States)

    Cerling, Thure E.; Barnette, Janet E.; Bowen, Gabriel J.; Chesson, Lesley A.; Ehleringer, James R.; Remien, Christopher H.; Shea, Patrick; Tipple, Brett J.; West, Jason B.

    2016-06-01

    Stable isotopes are being used for forensic science studies, with applications to both natural and manufactured products. In this review we discuss how scientific evidence can be used in the legal context and where the scientific progress of hypothesis revisions can be in tension with the legal expectations of widely used methods for measurements. Although this review is written in the context of US law, many of the considerations of scientific reproducibility and acceptance of relevant scientific data span other legal systems that might apply different legal principles and therefore reach different conclusions. Stable isotopes are used in legal situations for comparing samples for authenticity or evidentiary considerations, in understanding trade patterns of illegal materials, and in understanding the origins of unknown decedents. Isotope evidence is particularly useful when considered in the broad framework of physiochemical processes and in recognizing regional to global patterns found in many materials, including foods and food products, drugs, and humans. Stable isotopes considered in the larger spatial context add an important dimension to forensic science.

  5. Insights into the mechanism of Piper betle leaf-induced contact leukomelanosis using C57BL/6 mice as the animal model and tyrosinase assays.

    Science.gov (United States)

    Liu, Han-Nan; Liu, Tsung-Yun; Chen, Chih-Chiang; Lee, Ding-Dar; Chang, Yun-Ting

    2011-08-01

    Steamed piper betle leaves (PBL) were once used by many Taiwanese women to treat pigment disorders on the face. Most women claimed a quick, favourable response at first, only to be overcome with facial leukomelanosis later. C57BL/6 mice were randomly assigned to different groups to study if PBL could cause the following effects: contact dermatitis, leukomelanosis, or hair bleaching. Intracellular melanin content was measured by tyrosinase assays. Most steamed PBL-treated mice developed contact dermatitis and postinflammatory hyperpigmentation (PIH) on their shaved backs. About half developed bleached hair to varying extents. The steamed PBL did not only bleach the hairs, but also, unexpectedly, stimulated melanocyte replication, indicated by the fact that the number of functional melanocytes in the tail epidermis increased significantly after treatment (P = 0.007). Using tyrosinase assays PBL extract at the undiluted concentration showed limited inhibition of melanogenesis, probably via melanocytotoxicity. The leukomelanosis observed in patients might be the consequence of PIH combined with a mixed reaction (hyper- and hypopigmentation), probably due to the different volatile chemicals that surface after steaming the PBL. This conflicting mixed reaction suggests that counteractive ingredients might exist in PBL. PBL, if purified, might be a promising source of a novel bleaching agent. © 2011 The Authors; Australasian Journal of Dermatology © 2011 The Australasian College of Dermatologists.

  6. Optimization of extracellular catalase production from Aspergillus ...

    African Journals Online (AJOL)

    The studies of the effect of each variable and the establishment of a correlation between the response of enzyme activity and variables revealed that the link is a multiple linear regression form. The optimization was carried out through a simplex algorithm. The amount of extracellular catalase produced by the strain in the ...

  7. Managing Brain Extracellular K(+) during Neuronal Activity

    DEFF Research Database (Denmark)

    Larsen, Brian Roland; Stoica, Anca; MacAulay, Nanna

    2016-01-01

    characteristics required to fulfill their distinct physiological roles in clearance of K(+) from the extracellular space in the face of neuronal activity. Understanding the nature, impact and effects of the various Na(+)/K(+)-ATPase isoform combinations in K(+) management in the central nervous system might...... understanding of the pathological events occurring during disease....

  8. Extracellular vesicles: fundamentals and clinical relevance

    Directory of Open Access Journals (Sweden)

    Wael Nassar

    2015-01-01

    Full Text Available All types of cells of eukaryotic organisms produce and release small nanovesicles into their extracellular environment. Early studies have described these vesicles as ′garbage bags′ only to remove obsolete cellular molecules. Valadi and colleagues, in 2007, were the first to discover the capability of circulating extracellular vesicles (EVs to horizontally transfer functioning gene information between cells. These extracellular vesicles express components responsible for angiogenesis promotion, stromal remodeling, chemoresistance, genetic exchange, and signaling pathway activation through growth factor/receptor transfer. EVs represent an important mode of intercellular communication by serving as vehicles for transfer between cells of membrane and cytosolic proteins, lipids, signaling proteins, and RNAs. They contribute to physiology and pathology, and they have a myriad of potential clinical applications in health and disease. Moreover, vesicles can pass the blood-brain barrier and may perhaps even be considered as naturally occurring liposomes. These cell-derived EVs not only represent a central mediator of the disease microenvironment, but their presence in the peripheral circulation may serve as a surrogate for disease biopsies, enabling real-time diagnosis and disease monitoring. In this review, we′ll be addressing the characteristics of different types of extracellular EVs, as well as their clinical relevance and potential as diagnostic markers, and also define therapeutic options.

  9. Extracellular space diffusion and extrasynaptic transmission

    Czech Academy of Sciences Publication Activity Database

    Vargová, Lýdia; Syková, Eva

    2008-01-01

    Roč. 57, Suppl.3 (2008), S89-S99 ISSN 0862-8408 R&D Projects: GA MŠk 1M0538; GA MŠk(CZ) LC554 Institutional research plan: CEZ:AV0Z50390512 Keywords : Diffusion * Extracellular volume * Tortuosity Subject RIV: FH - Neurology Impact factor: 1.653, year: 2008

  10. Integrins and extracellular matrix in mechanotransduction

    Directory of Open Access Journals (Sweden)

    Ramage L

    2011-12-01

    Full Text Available Lindsay RamageQueen’s Medical Research Institute, University of Edinburgh, Edinburgh, UKAbstract: Integrins are a family of cell surface receptors which mediate cell–matrix and cell–cell adhesions. Among other functions they provide an important mechanical link between the cells external and intracellular environments while the adhesions that they form also have critical roles in cellular signal-transduction. Cell–matrix contacts occur at zones in the cell surface where adhesion receptors cluster and when activated the receptors bind to ligands in the extracellular matrix. The extracellular matrix surrounds the cells of tissues and forms the structural support of tissue which is particularly important in connective tissues. Cells attach to the extracellular matrix through specific cell-surface receptors and molecules including integrins and transmembrane proteoglycans. Integrins work alongside other proteins such as cadherins, immunoglobulin superfamily cell adhesion molecules, selectins, and syndecans to mediate cell–cell and cell–matrix interactions and communication. Activation of adhesion receptors triggers the formation of matrix contacts in which bound matrix components, adhesion receptors, and associated intracellular cytoskeletal and signaling molecules form large functional, localized multiprotein complexes. Cell–matrix contacts are important in a variety of different cell and tissue properties including embryonic development, inflammatory responses, wound healing, and adult tissue homeostasis. This review summarizes the roles and functions of integrins and extracellular matrix proteins in mechanotransduction.Keywords: ligand binding, α subunit, ß subunit, focal adhesion, cell differentiation, mechanical loading, cell–matrix interaction

  11. Interaction of acetamiprid with extracellular polymeric substances ...

    African Journals Online (AJOL)

    Extracellular polymeric substances (EPS) are important components of activated sludge and it plays an important role in removing pollutants. The interaction between EPS and organic pollutants is still little known. In the present study, the interaction of soluble/bound EPS with acetamiprid, a neonicotinoid insecticide, was ...

  12. Optimization of extracellular catalase production from Aspergillus ...

    African Journals Online (AJOL)

    aghomotsegin

    extracellular catalase produced by the strain in the optimized medium was about four times higher than ... celial and unicellular fungi in synthetic media (Kurakov et .... covering the appropriate range and the broad calibration kit ... This optimization allowed us to define new cultural con- ..... Ann. New York Academy Sci.

  13. Production of extracellular aspartic protease in submerged ...

    African Journals Online (AJOL)

    Fungal milk-clotting enzymes have gained value as bovine Chymosin substitutes in the cheese industry. In this work, the effects of culture conditions on the production of extracellular milk clotting enzymes from Mucor mucedo DSM 809 in submerged fermentation were studied. The maximum activity was observed after 48 h ...

  14. Extracellular matrix and tissue engineering applications

    NARCIS (Netherlands)

    Fernandes, H.A.M.; Moroni, Lorenzo; van Blitterswijk, Clemens; de Boer, Jan

    2009-01-01

    The extracellular matrix is a key component during regeneration and maintenance of tissues and organs, and it therefore plays a critical role in successful tissue engineering as well. Tissue engineers should recognise that engineering technology can be deduced from natural repair processes. Due to

  15. Analysis of P gene mutations in patients with type II (tyrosinase-positive) oculocutaneous albinism (OCA2)

    Energy Technology Data Exchange (ETDEWEB)

    Lee, S.T.; Nicholls, R.D.; Schnur, R. [Univ. of Wisconsin, Madison, WI (United States)]|[Case Western Reserve Univ., Cleveland, OH (United States)]|[Children`s Hospital of Philadelphia, PA (United States)] [and others

    1994-09-01

    OCA2 is an autosomal recessive disorder in which the biosynthesis of melanin pigment is greatly reduced in the skin, hair, and eyes. Recently, we showed that OCA2 results from mutations of the P gene, in chromosome segment 15q11-q13. In addition to OCA2, mutations of P account for OCA associated with the Prader-Willi syndrome and some cases of {open_quotes}autosomal recessive ocular albinism{close_quotes} (AROA). We have now studied 38 unrelated patients with various forms of OCA2 or AROA from a variety of different ethnic groups. None of these patients had detectable abnormalities of the tyrosinase (TYR) gene. Among 8 African-American patients with OCA2 we observed apparent locus homogeneity. We detected abnormalities of the P gene in all 8 patients, including 12 different mutations and deletions, most of which are unique to this group and none of which is predominant. In contrast, OCA2 in other populations appears to be genetically heterogeneous. Among 21 Caucasian patients we detected abnormalities of the P gene in only 8, comprising 9 different point mutations and deletions, some of which also occurred among the African-American patients. Among 3 Middle-Eastern, 3 Indo-Pakistani, and 3 Asian patients we detected mutations of the P gene in only one from each group. In a large Indo-Pakistani kindred with OCA2 we have excluded both the TYR and P genes on the basis of genetic linkage. The prevalence of mutations of the P gene thus appears to be much higher among African-Americans with OCA2 than among patients from other ethnic groups. The incidence of OCA2 in some parts of equatorial Africa is extremely high, as frequent as 1 per 1100, and the disease has been linked to P in South African Bantu. The eventual characterization of P gene mutations in Africans will be informative with regard to the origins of P gene mutations in African-American patients.

  16. Interferon-gamma (IFN-γ-mediated retinal ganglion cell death in human tyrosinase T cell receptor transgenic mouse.

    Directory of Open Access Journals (Sweden)

    Shahid Husain

    Full Text Available We have recently demonstrated the characterization of human tyrosinase TCR bearing h3T-A2 transgenic mouse model, which exhibits spontaneous autoimmune vitiligo and retinal dysfunction. The purpose of current study was to determine the role of T cells and IFN-γ in retina dysfunction and retinal ganglion cell (RGC death using this model. RGC function was measured by pattern electroretinograms (ERGs in response to contrast reversal of patterned visual stimuli. RGCs were visualized by fluorogold retrograde-labeling. Expression of CD3, IFN-γ, GFAP, and caspases was measured by immunohistochemistry and Western blotting. All functional and structural changes were measured in 12-month-old h3T-A2 mice and compared with age-matched HLA-A2 wild-type mice. Both pattern-ERGs (42%, p = 0.03 and RGC numbers (37%, p = 0.0001 were reduced in h3T-A2 mice when compared with wild-type mice. The level of CD3 expression was increased in h3T-A2 mice (h3T-A2: 174 ± 27% vs. HLA-A2: 100%; p = 0.04. The levels of effector cytokine IFN-γ were also increased significantly in h3T-A2 mice (h3T-A2: 189 ± 11% vs. HLA-A2: 100%; p = 0.023. Both CD3 and IFN-γ immunostaining were increased in nerve fiber (NF and RGC layers of h3T-A2 mice. In addition, we have seen a robust increase in GFAP staining in h3T-A2 mice (mainly localized to NF layer, which was substantially reduced in IFN-γ ((-/- knockout h3T-A2 mice. We also have seen an up-regulation of caspase-3 and -9 in h3T-A2 mice. Based on our data we conclude that h3T-A2 transgenic mice exhibit visual defects that are mostly associated with the inner retinal layers and RGC function. This novel h3T-A2 transgenic mouse model provides opportunity to understand RGC pathology and test neuroprotective strategies to rescue RGCs.

  17. Extracellular nucleotide derivatives protect cardiomyctes against hypoxic stress

    DEFF Research Database (Denmark)

    Golan, O; Issan, Y; Isak, A

    2011-01-01

    assures cardioprotection. Treatment with extracellular nucleotides, or with tri/di-phosphate, administered under normoxic conditions or during hypoxic conditions, led to a decrease in reactive oxygen species production. CONCLUSIONS: Extracellular tri/di-phosphates are apparently the molecule responsible...

  18. Involvement of extracellular matrix constituents in breast cancer

    Energy Technology Data Exchange (ETDEWEB)

    Lochter, Andre; Bissell, Mina J

    1995-06-01

    It has recently been established that the extracellular matrix is required for normal functional differentiation of mammary epithelia not only in culture, but also in vivo. The mechanisms by which extracellular matrix affects differentiation, as well as the nature of extracellular matrix constituents which have major impacts on mammary gland function, have only now begun to be dissected. The intricate variety of extracellular matrix-mediated events and the remarkable degree of plasticity of extracellular matrix structure and composition at virtually all times during ontogeny, make such studies difficult. Similarly, during carcinogenesis, the extracellular matrix undergoes gross alterations, the consequences of which are not yet precisely understood. Nevertheless, an increasing amount of data suggests that the extracellular matrix and extracellular matrix-receptors might participate in the control of most, if not all, of the successive stages of breast tumors, from appearance to progression and metastasis.

  19. Theory of stable allocations

    Directory of Open Access Journals (Sweden)

    Pantelić Svetlana

    2014-01-01

    Full Text Available The Swedish Royal Academy awarded the 2012 Nobel Prize in Economics to Lloyd Shapley and Alvin Roth, for the theory of stable allocations and the practice of market design. These two American researchers worked independently from each other, combining basic theory and empirical investigations. Through their experiments and practical design they generated a flourishing field of research and improved the performance of many markets. Born in 1923 in Cambridge, Massachusetts, Shapley defended his doctoral thesis at Princeton University in 1953. For many years he worked at RAND, and for more than thirty years he was a professor at UCLA University. He published numerous scientific papers, either by himself or in cooperation with other economists.

  20. Bi-stable optical actuator

    Science.gov (United States)

    Holdener, Fred R.; Boyd, Robert D.

    2000-01-01

    The present invention is a bi-stable optical actuator device that is depowered in both stable positions. A bearing is used to transfer motion and smoothly transition from one state to another. The optical actuator device may be maintained in a stable position either by gravity or a restraining device.

  1. Extracellular signaling and multicellularity in Bacillus subtilis.

    Science.gov (United States)

    Shank, Elizabeth Anne; Kolter, Roberto

    2011-12-01

    Bacillus subtilis regulates its ability to differentiate into distinct, co-existing cell types in response to extracellular signaling molecules produced either by itself, or present in its environment. The production of molecules by B. subtilis cells, as well as their response to these signals, is not uniform across the population. There is specificity and heterogeneity both within genetically identical populations as well as at the strain-level and species-level. This review will discuss how extracellular signaling compounds influence B. subtilis multicellularity with regard to matrix-producing cannibal differentiation, germination, and swarming behavior, as well as the specificity of the quorum-sensing peptides ComX and CSF. It will also highlight how imaging mass spectrometry can aid in identifying signaling compounds and contribute to our understanding of the functional relationship between such compounds and multicellular behavior. Copyright © 2011 Elsevier Ltd. All rights reserved.

  2. Biotechnological Aspects of Microbial Extracellular Electron Transfer

    Science.gov (United States)

    Kato, Souichiro

    2015-01-01

    Extracellular electron transfer (EET) is a type of microbial respiration that enables electron transfer between microbial cells and extracellular solid materials, including naturally-occurring metal compounds and artificial electrodes. Microorganisms harboring EET abilities have received considerable attention for their various biotechnological applications, in addition to their contribution to global energy and material cycles. In this review, current knowledge on microbial EET and its application to diverse biotechnologies, including the bioremediation of toxic metals, recovery of useful metals, biocorrosion, and microbial electrochemical systems (microbial fuel cells and microbial electrosynthesis), were introduced. Two potential biotechnologies based on microbial EET, namely the electrochemical control of microbial metabolism and electrochemical stimulation of microbial symbiotic reactions (electric syntrophy), were also discussed. PMID:26004795

  3. Methods to isolate extracellular vesicles for diagnosis

    Science.gov (United States)

    Kang, Hyejin; Kim, Jiyoon; Park, Jaesung

    2017-12-01

    Extracellular vesicles (EVs) are small membrane-bound bodies that are released into extracellular space by diverse cells, and are found in body fluids like blood, urine and saliva. EVs contain RNA, DNA and proteins, which can be biomarkers for diagnosis. EVs can be obtained by minimally-invasive biopsy, so they are useful in disease diagnosis. High yield and purity contribute to precise diagnosis of disease, but damaged EVs and impurities can cause confu sed results. However, EV isolation methods have different yields and purities. Furthermore, the isolation method that is most suitable to maximize EV recovery efficiency depends on the experimental conditions. This review focuses on merits and demerits of several types of EV isolation methods, and provides examples of how to diagnose disease by exploiting information obtained by analysis of EVs.

  4. Stem cell extracellular vesicles and kidney injury

    OpenAIRE

    Grange, Cristina; Iampietro, Corinne; Bussolati, Benedetta

    2017-01-01

    Extracellular vesicles (EVs) appear as a new promising cell-free therapy for acute and chronic renal diseases. EVs retain characteristics of the cell of origin and those derived from stem cells may mimic their regenerative properties per se. In fact, EVs contain many active molecules such as proteins and RNA species that act on target cells through different mechanisms, stimulating proliferation and angiogenesis and reducing apoptosis and inflammation. There are several reports that demonstra...

  5. Extracellular deoxyribonuclease production by periodontal bacteria.

    Science.gov (United States)

    Palmer, L J; Chapple, I L C; Wright, H J; Roberts, A; Cooper, P R

    2012-08-01

    Whilst certain bacteria have long been known to secrete extracellular deoxyribonuclease (DNase), the purpose in microbial physiology was unclear. Recently, however, this enzyme has been demonstrated to confer enhanced virulence, enabling bacteria to evade the host's immune defence of extruded DNA/chromatin filaments, termed neutrophil extracellular traps (NETs). As NETs have recently been identified in infected periodontal tissue, the aim of this study was to screen periodontal bacteria for extracellular DNase activity. To determine whether DNase activity was membrane bound or secreted, 34 periodontal bacteria were cultured in broth and on agar plates. Pelleted bacteria and supernatants from broth cultures were analysed for their ability to degrade DNA, with relative activity levels determined using an agarose gel electrophoresis assay. Following culture on DNA-supplemented agar, expression was determined by the presence of a zone of hydrolysis and DNase activity related to colony size. Twenty-seven bacteria, including red and orange complex members Porphyromonas gingivalis, Tannerella forsythia, Fusobacterium nucleatum, Parvimonas micra, Prevotella intermedia, Streptococcus constellatus, Campylobacter rectus and Prevotella nigrescens, were observed to express extracellular DNase activity. Differences in DNase activity were noted, however, when bacteria were assayed in different culture states. Analysis of the activity of secreted DNase from bacterial broth cultures confirmed their ability to degrade NETs. The present study demonstrates, for the first time, that DNase activity is a relatively common property of bacteria associated with advanced periodontal disease. Further work is required to determine the importance of this bacterial DNase activity in the pathogenesis of periodontitis. © 2011 John Wiley & Sons A/S.

  6. Extracellular matrix component signaling in cancer

    DEFF Research Database (Denmark)

    Multhaupt, Hinke A. B.; Leitinger, Birgit; Gullberg, Donald

    2016-01-01

    Cell responses to the extracellular matrix depend on specific signaling events. These are important from early development, through differentiation and tissue homeostasis, immune surveillance, and disease pathogenesis. Signaling not only regulates cell adhesion cytoskeletal organization and motil...... as well as matrix constitution and protein crosslinking. Here we summarize roles of the three major matrix receptor types, with emphasis on how they function in tumor progression. [on SciFinder(R)]...

  7. Autocrine signal transmission with extracellular ligand degradation

    International Nuclear Information System (INIS)

    Muratov, C B; Posta, F; Shvartsman, S Y

    2009-01-01

    Traveling waves of cell signaling in epithelial layers orchestrate a number of important processes in developing and adult tissues. These waves can be mediated by positive feedback autocrine loops, a mode of cell signaling where binding of a diffusible extracellular ligand to a cell surface receptor can lead to further ligand release. We formulate and analyze a biophysical model that accounts for ligand-induced ligand release, extracellular ligand diffusion and ligand–receptor interaction. We focus on the case when the main mode for ligand degradation is extracellular and analyze the problem with the sharp threshold positive feedback nonlinearity. We derive expressions that link the speed of propagation and other characteristics of traveling waves to the parameters of the biophysical processes, such as diffusion rates, receptor expression level, etc. Analyzing the derived expressions we found that traveling waves in such systems can exhibit a number of unusual properties, e.g. non-monotonic dependence of the speed of propagation on ligand diffusivity. Our results for the fully developed traveling fronts can be used to analyze wave initiation from localized perturbations, a scenario that frequently arises in the in vitro models of epithelial wound healing, and guide future modeling studies of cell communication in epithelial layers

  8. Extracellular proteases of Trichoderma species. A review.

    Science.gov (United States)

    Kredics, L; Antal, Zsuzsanna; Szekeres, A; Hatvani, L; Manczinger, L; Vágvölgyi, Cs; Nagy, Erzsébet

    2005-01-01

    Cellulolytic, xylanolytic, chitinolytic and beta-1,3-glucanolytic enzyme systems of species belonging to the filamentous fungal genus Trichoderma have been investigated in details and are well characterised. The ability of Trichoderma strains to produce extracellular proteases has also been known for a long time, however, the proteolytic enzyme system is relatively unknown in this genus. Fortunately, in the recent years more and more attention is focused on the research in this field. The role of Trichoderma proteases in the biological control of plant pathogenic fungi and nematodes has been demonstrated, and it is also suspected that they may be important for the competitive saprophytic ability of green mould isolates and may represent potential virulence factors of Trichoderma strains as emerging fungal pathogens of clinical importance. The aim of this review is to summarize the information available about the extracellular proteases of Trichoderma. Numerous studies are available about the extracellular proteolytic enzyme profiles of Trichoderma strains and about the effect of abiotic environmental factors on protease activities. A number of protease enzymes have been purified to homogeneity and some protease encoding genes have been cloned and characterized. These results will be reviewed and the role of Trichoderma proteases in biological control as well as their advantages and disadvantages in biotechnology will be discussed.

  9. EXTRACELLULAR VESICLES: CLASSIFICATION, FUNCTIONS AND CLINICAL RELEVANCE

    Directory of Open Access Journals (Sweden)

    A. V. Oberemko

    2014-12-01

    Full Text Available This review presents a generalized definition of vesicles as bilayer extracellular organelles of all celular forms of life: not only eu-, but also prokaryotic. The structure and composition of extracellular vesicles, history of research, nomenclature, their impact on life processes in health and disease are discussed. Moreover, vesicles may be useful as clinical instruments for biomarkers, and they are promising as biotechnological drug. However, many questions in this area are still unresolved and need to be addressed in the future. The most interesting from the point of view of practical health care represents a direction to study the effect of exosomes and microvesicles in the development and progression of a particular disease, the possibility of adjusting the pathological process by means of extracellular vesicles of a particular type, acting as an active ingredient. Relevant is the further elucidation of the role and importance of exosomes to the surrounding cells, tissues and organs at the molecular level, the prospects for the use of non-cellular vesicles as biomarkers of disease.

  10. Autocrine signal transmission with extracellular ligand degradation

    Science.gov (United States)

    Muratov, C B; Posta, F; Shvartsman, S Y

    2009-03-01

    Traveling waves of cell signaling in epithelial layers orchestrate a number of important processes in developing and adult tissues. These waves can be mediated by positive feedback autocrine loops, a mode of cell signaling where binding of a diffusible extracellular ligand to a cell surface receptor can lead to further ligand release. We formulate and analyze a biophysical model that accounts for ligand-induced ligand release, extracellular ligand diffusion and ligand-receptor interaction. We focus on the case when the main mode for ligand degradation is extracellular and analyze the problem with the sharp threshold positive feedback nonlinearity. We derive expressions that link the speed of propagation and other characteristics of traveling waves to the parameters of the biophysical processes, such as diffusion rates, receptor expression level, etc. Analyzing the derived expressions we found that traveling waves in such systems can exhibit a number of unusual properties, e.g. non-monotonic dependence of the speed of propagation on ligand diffusivity. Our results for the fully developed traveling fronts can be used to analyze wave initiation from localized perturbations, a scenario that frequently arises in the in vitro models of epithelial wound healing, and guide future modeling studies of cell communication in epithelial layers.

  11. Chaotic Dynamics Mediates Brain State Transitions, Driven by Changes in Extracellular Ion Concentrations

    DEFF Research Database (Denmark)

    Rasmussen, Rune; H. Jensen, Mogens; L. Heltberg, Mathias

    2017-01-01

    Previous studies have suggested that changes in extracellular ion concentrations initiate the transition from an activity state that characterizes sleep in cortical neurons to states that characterize wakeful- ness. However, because neuronal activity and extra- cellular ion concentrations...... are interdependent, isolating their unique roles during sleep-wake transitions is not possible in vivo. Here, we extend the Averaged-Neuron model and demonstrate that, although changes in extracellular ion concentrations occur concurrently, decreasing the conductance of calcium-dependent potassium channels initiates...... the transition from sleep to wakefulness. We find that sleep is governed by stable, self-sustained oscillations in neuronal firing patterns, whereas the quiet awake state and active awake state are both governed by irregular oscillations and chaotic dynamics; transitions between these separable awake states...

  12. Comparative studies on the correlation between pyrimidine dimer formation and tyrosinase activity in Cloudman S91 melanoma cells after ultraviolet-irradiation

    International Nuclear Information System (INIS)

    Niggli, H.J.

    1990-01-01

    The authors compared the induction of pyrimidine dimer densities after UV-irradiation in mouse melanoma cells before and after treatment with cholera toxin. Treatment with cholera toxin stimulated tyrosinase activity up to 50-fold, leading to a marked, visually apparent increase in cellular melanin concentrations. Results indicate that de novo melanin pigmentation induced via the c-AMP pathway is not involved in protection against UV-induced thymine-containing pyrimidine dimers. In separate experiments, irradiation of toxin-treated and untreated mouse melanoma cells with UVC or UVB light produced a 20-30% lower dimer density compared to irradiated human skin fibroblasts. This finding suggests that melanin has some protection properties against UV-induced pyrimidine dimers, although the exact defense mechanism seems highly complex. (author)

  13. Functional analysis of a tyrosinase gene involved in early larval shell biogenesis in Crassostrea angulata and its response to ocean acidification.

    Science.gov (United States)

    Yang, Bingye; Pu, Fei; Li, Lingling; You, Weiwei; Ke, Caihuan; Feng, Danqing

    2017-04-01

    The formation of the primary shell is a vital process in marine bivalves. Ocean acidification largely influences shell formation. It has been reported that enzymes involved in phenol oxidation, such as tyrosinase and phenoloxidases, participate in the formation of the periostracum. In the present study, we cloned a tyrosinase gene from Crassostrea angulata named Ca-tyrA1, and its potential function in early larval shell biogenesis was investigated. The Ca-tyrA1 gene has a full-length cDNA of 2430bp in size, with an open reading frame of 1896bp in size, which encodes a 631-amino acid protein that includes a 24-amino acid putative signal peptide. Quantitative reverse transcription-polymerase chain reaction (qRT-PCR) analysis revealed that Ca-tyrA1 transcription mainly occurs at the trochophore stage, and the Ca-tyrA1 mRNA levels in the 3000ppm treatment group were significantly upregulated in the early D-veliger larvae. WMISH and electron scanning microscopy analyses showed that the expression of Ca-tyrA1 occurs at the gastrula stage, thereby sustaining the early D-veliger larvae, and the shape of its signal is saddle-like, similar to that observed under an electron scanning microscope. Furthermore, the RNA interference has shown that the treatment group has a higher deformity rate than that of the control, thereby indicating that Ca-tyrA1 participates in the biogenesis of the primary shell. In conclusion, and our results indicate that Ca-tyrA1 plays a vital role in the formation of the larval shell and participates in the response to larval shell damages in Crassostrea angulata that were induced by ocean acidification. Copyright © 2017 Elsevier Inc. All rights reserved.

  14. Long term presence of a single predominant tyrosinase-specific T-cell clone associated with disease control in a patient with metastatic melanoma.

    Science.gov (United States)

    Ochsenreither, Sebastian; Fusi, Alberto; Busse, Antonia; Letsch, Anne; Haase, Doreen; Thiel, Eckhard; Scheibenbogen, Carmen; Keilholz, Ulrich

    2010-05-15

    In an earlier study, we described a patient who developed an anti-tyrosinase T-cell response leading to long-term tumor control. Here we analyzed this response with regard to T-cell receptor (TCR) Vbeta family usage and clonality in order to further elucidate the nature of the T cell response in this patient. For identification of expanded specific cytotoxic T-cell (CTL) clones, tetramer enrichment of tyrosinase reactive T-cells was followed by comparative quantitative reverse transcribed PCR (qRT PCR) quantification of all TCR Vbeta-families and sequencing of family Vbeta4 elevated in the enriched fraction. The predominant specific clone was quantified by clonotypic qRT PCR in multiple samples from blood, bone marrow, and tumor tissue. FACS analyses with staining of TYR.A2 and TCR Vbeta4 were performed. Epitope specific enrichment revealed an isolated increase of Vbeta-family 4. FACS analysis showed a shift of specific CTLs to Vbeta-family 4 during tumor regression with a maximum of 80% of all TYR.A2 specific cells belonging to this family. Sequencing revealed a single predominant clone against polyclonal background coding for identical CDR3 loops. The predominant clone was highly expressed in bone marrow and tumor tissue, and was detectable in blood over a period of ten years. Considering the results of previous studies showing a specific effector phenotype in blood and a specific memory compartment in bone marrow of this patient, this data implicate the predominant clone featured all attributes of a sufficient CTL response including homing capacity and memory formation resulting in long term clonal persistence and tumor control.

  15. Indication of Horizontal DNA Gene Transfer by Extracellular Vesicles.

    Directory of Open Access Journals (Sweden)

    Stefanie Fischer

    Full Text Available The biological relevance of extracellular vesicles (EV in intercellular communication has been well established. Thus far, proteins and RNA were described as main cargo. Here, we show that EV released from human bone marrow derived mesenchymal stromal cells (BM-hMSC also carry high-molecular DNA in addition. Extensive EV characterization revealed this DNA mainly associated with the outer EV membrane and to a smaller degree also inside the EV. Our EV purification protocol secured that DNA is not derived from apoptotic or necrotic cells. To analyze the relevance of EV-associated DNA we lentivirally transduced Arabidopsis thaliana-DNA (A.t.-DNA as indicator into BM-hMSC and generated EV. Using quantitative polymerase chain reaction (qPCR techniques we detected high copy numbers of A.t.-DNA in EV. In recipient hMSC incubated with tagged EV for two weeks we identified A.t.-DNA transferred to recipient cells. Investigation of recipient cell DNA using quantitative PCR and verification of PCR-products by sequencing suggested stable integration of A.t.-DNA. In conclusion, for the first time our proof-of-principle experiments point to horizontal DNA transfer into recipient cells via EV. Based on our results we assume that eukaryotic cells are able to exchange genetic information in form of DNA extending the known cargo of EV by genomic DNA. This mechanism might be of relevance in cancer but also during cell evolution and development.

  16. Extracellular Gd-CA: Differences in prevalence of NSF

    International Nuclear Information System (INIS)

    Thomsen, Henrik S.; Marckmann, Peter

    2008-01-01

    Until recently it was believed that extracellular gadolinium-based contrast agents were safe for both the kidneys and all other organs within the dose range up to 0.3 mmol/kg body weight. However, in 2006, it was demonstrated that some gadolinium-based contrast agents may trig the development of nephrogenic systemic fibrosis, a generalized fibrotic disorder, in renal failure patients. As no prospective studies can be performed we must rely on retrospective data. From those data it is obvious that the prevalence of NSF is significantly higher after the unstable agent gadodiamide than after any other gadolinium-based agent (3-7% versus 0-1% per injection) in patients with reduced renal function. Prevalence after exposure to two gadodiamide injections is as high as 36% in patients with chronic kidney disease (CKD) stage 5. No report of NSF after the most stable agents has been reported in the peer-reviewed literature documenting that there is a difference between the various agents regarding triggering NSF

  17. Extracellular Signatures as Indicators of Processing Methods

    Energy Technology Data Exchange (ETDEWEB)

    Wahl, Karen L.

    2012-01-09

    As described in other chapters within this volume, many aspects of microbial cells vary with culture conditions and therefore can potentially be analyzed as forensic signatures of growth conditions. In addition to changes or variations in components of the microbes themselves, extracellular materials indicative of production processes may remain associated with the final bacterial product. It is well recognized that even with considerable effort to make pure products such as fine chemicals or pharmaceuticals, trace impurities from components or synthesis steps associated with production processes can be detected in the final product. These impurities can be used as indicators of production source or methods, such as to help connect drugs of abuse to supply chains. Extracellular residue associated with microbial cells could similarly help to characterize production processes. For successful growth of microorganisms on culture media there must be an available source of carbon, nitrogen, inorganic phosphate and sulfur, trace metals, water and vitamins. The pH, temperature, and a supply of oxygen or other gases must also be appropriate for a given organism for successful culture. The sources of these components and the range in temperature, pH and other variables has adapted over the years with currently a wide range of possible combinations of media components, recipes and parameters to choose from for a given organism. Because of this wide variability in components, mixtures of components, and other parameters, there is the potential for differentiation of cultured organisms based on changes in culture conditions. The challenge remains how to narrow the field of potential combinations and be able to attribute variations in the final bacterial product and extracellular signatures associated with the final product to information about the culture conditions or recipe used in the production of that product.

  18. Regulation of corneal stroma extracellular matrix assembly.

    Science.gov (United States)

    Chen, Shoujun; Mienaltowski, Michael J; Birk, David E

    2015-04-01

    The transparent cornea is the major refractive element of the eye. A finely controlled assembly of the stromal extracellular matrix is critical to corneal function, as well as in establishing the appropriate mechanical stability required to maintain corneal shape and curvature. In the stroma, homogeneous, small diameter collagen fibrils, regularly packed with a highly ordered hierarchical organization, are essential for function. This review focuses on corneal stroma assembly and the regulation of collagen fibrillogenesis. Corneal collagen fibrillogenesis involves multiple molecules interacting in sequential steps, as well as interactions between keratocytes and stroma matrix components. The stroma has the highest collagen V:I ratio in the body. Collagen V regulates the nucleation of protofibril assembly, thus controlling the number of fibrils and assembly of smaller diameter fibrils in the stroma. The corneal stroma is also enriched in small leucine-rich proteoglycans (SLRPs) that cooperate in a temporal and spatial manner to regulate linear and lateral collagen fibril growth. In addition, the fibril-associated collagens (FACITs) such as collagen XII and collagen XIV have roles in the regulation of fibril packing and inter-lamellar interactions. A communicating keratocyte network contributes to the overall and long-range regulation of stromal extracellular matrix assembly, by creating micro-domains where the sequential steps in stromal matrix assembly are controlled. Keratocytes control the synthesis of extracellular matrix components, which interact with the keratocytes dynamically to coordinate the regulatory steps into a cohesive process. Mutations or deficiencies in stromal regulatory molecules result in altered interactions and deficiencies in both transparency and refraction, leading to corneal stroma pathobiology such as stromal dystrophies, cornea plana and keratoconus. Copyright © 2014 Elsevier Ltd. All rights reserved.

  19. Light Regimes Shape Utilization of Extracellular Organic C and N in a Cyanobacterial Biofilm

    Energy Technology Data Exchange (ETDEWEB)

    Stuart, Rhona K.; Mayali, Xavier; Boaro, Amy A.; Zemla, Adam; Everroad, R. Craig; Nilson, Daniel; Weber, Peter K.; Lipton, Mary; Bebout, Brad M.; Pett-Ridge, Jennifer; Thelen, Michael P.

    2016-06-28

    >IMPORTANCECyanobacteria are globally distributed primary producers, and the fate of their fixed C influences microbial biogeochemical cycling. This fate is complicated by cyanobacterial degradation and assimilation of organic matter, but because cyanobacteria are assumed to be poor competitors for organic matter consumption, regulation of this process is not well tested. In mats and biofilms, this is especially relevant because cyanobacteria produce an extensive organic extracellular matrix, providing the community with a rich source of nutrients. Light is a well-known regulator of cyanobacterial metabolism, so we characterized the effects of light availability on the incorporation of organic matter. Using stable isotope tracing at the single-cell level, we quantified photoautotroph assimilation under different metabolic conditions and integrated the results with proteomics to elucidate metabolic status. We found that cyanobacteria effectively compete for organic matter in the light and the dark and that nutrient requirements and community interactions contribute to cycling of extracellular organic matter.

  20. One-dimensional stable distributions

    CERN Document Server

    Zolotarev, V M

    1986-01-01

    This is the first book specifically devoted to a systematic exposition of the essential facts known about the properties of stable distributions. In addition to its main focus on the analytic properties of stable laws, the book also includes examples of the occurrence of stable distributions in applied problems and a chapter on the problem of statistical estimation of the parameters determining stable laws. A valuable feature of the book is the author's use of several formally different ways of expressing characteristic functions corresponding to these laws.

  1. Nanostructured gold microelectrodes for extracellular recording

    Energy Technology Data Exchange (ETDEWEB)

    Brueggemann, Dorothea; Wolfrum, Bernhard; Maybeck, Vanessa; Offenhaeusser, Andreas [CNI Center of Nanoelectronic Systems for Information Technology and Institute of Bio- and Nanosystems 2, Forschungszentrum Juelich (Germany)

    2010-07-01

    Electrophysiological activity of electrogenic cells is currently recorded with planar bioelectronic interfaces such as microelectrode arrays (MEAs). In this work, a novel concept of biocompatible nanostructured gold MEAs for extracellular signal recording is presented. MEAs were fabricated using clean room technologies, e.g. photolithography and metallization. Subsequently, they were modified with gold nanopillars of approximately 300 to 400 nm in height and 60 nm width. The nanostructuring process was carried out with a template-assisted approach using nanoporous aluminium oxide. Impedance spectroscopy of the resulting nanostructures showed higher capacitances compared to planar gold. This confirmed the expected increase of the surface area via nanostructuring. We used the nanostructured microelectrodes to record extracellular potentials from heart muscle cells (HL1), which were plated onto the chips. Good coupling between the HL1 cells and the nanostructured electrodes was observed. The resulting signal-to-noise ratio of nanopillar-MEAs was increased by a factor of 2 compared to planar MEAs. In future applications this nanopillar concept can be adopted for distinct interface materials and coupling to cellular and molecular sensing components.

  2. Secretory proteins of the pulmonary extracellular lining

    International Nuclear Information System (INIS)

    Gupta, R.P.; Patton, S.E.; Eddy, M.; Smits, H.L.; Jetten, A.M.; Nettesheim, P.; Hook, G.E.R.

    1986-01-01

    The objective of this investigation was to identify proteins in the pulmonary extracellular lining (EL) that are secreted by cells of the pulmonary epithelium. Pulmonary lavage effluents from the lungs of rabbits were centrifuged to remove all cells and particulate materials. Serum proteins were removed by repeatedly passing concentrated lavage effluent fluid through an affinity column containing IgG fraction of goat anti-rabbit (whole serum) antiserum bound to Sepharose-4B. Nonserum proteins accounted for 21.3 +/- 10.3% of the total soluble proteins in pulmonary lavage effluents. Serum free lavage effluents (SFL) contained 25 identifiable proteins as determined by using SDS-PAGE under reducing conditions. Of these proteins approximately 73% was accounted for by a single protein with MW of 66 kd. The secretory nature of the proteins present in SFL was investigated by studying the incorporation of 35 S-methionine into proteins released by lung slices and trachea followed by SDS-PAGE and autoradiography. Many, but not all proteins present in SFL were identified as proteins secreted by pulmonary tissues. The major secretory proteins appeared to have MWs of 59, 53, 48, 43, 24, 14, and 6 kd under reducing conditions. These data demonstrate the presence of several proteins in the pulmonary extracellular lining that appear to be secreted by the pulmonary epithelium

  3. Extracellular histones induce erythrocyte fragility and anemia.

    Science.gov (United States)

    Kordbacheh, Farzaneh; O'Meara, Connor H; Coupland, Lucy A; Lelliott, Patrick M; Parish, Christopher R

    2017-12-28

    Extracellular histones have been shown to play an important pathogenic role in many diseases, primarily through their cytotoxicity toward nucleated cells and their ability to promote platelet activation with resultant thrombosis and thrombocytopenia. In contrast, little is known about the effect of extracellular histones on erythrocyte function. We demonstrate in this study that histones promote erythrocyte aggregation, sedimentation, and using a novel in vitro shear stress model, we show that histones induce erythrocyte fragility and lysis in a concentration-dependent manner. Furthermore, histones impair erythrocyte deformability based on reduced passage of erythrocytes through an artificial spleen. These in vitro results were mirrored in vivo with the injection of histones inducing anemia within minutes of administration, with a concomitant increase in splenic hemoglobin content. Thrombocytopenia and leukopenia were also observed. These findings suggest that histones binding to erythrocytes may contribute to the elevated erythrocyte sedimentation rates observed in inflammatory conditions. Furthermore, histone-induced increases in red blood cell lysis and splenic clearance may be a significant factor in the unexplained anemias seen in critically ill patients. © 2017 by The American Society of Hematology.

  4. The International Society for Extracellular Vesicles launches the first massive open online course on extracellular vesicles.

    Science.gov (United States)

    Lässer, Cecilia; Théry, Clotilde; Buzás, Edit I; Mathivanan, Suresh; Zhao, Weian; Gho, Yong Song; Lötvall, Jan

    2016-01-01

    The International Society for Extracellular Vesicles (ISEV) has organised its first educational online course for students and beginners in the field of extracellular vesicles (EVs). This course, "Basics of Extracellular Vesicles," uses recorded lectures from experts in the field and will be open for an unlimited number of participants. The course is divided into 5 modules and can be accessed at www.coursera.org/learn/extracellular-vesicles. The first module is an introduction to the field covering the nomenclature and history of EVs. Module 2 focuses on the biogenesis and uptake mechanisms of EVs, as well as their RNA, protein and lipid cargo. Module 3 covers the collection and processing of cell culture media and body fluids such as blood, breast milk, cerebrospinal fluid and urine prior to isolation of EVs. Modules 4 and 5 present different isolation methods and characterisation techniques utilised in the EV field. Here, differential ultracentrifugation, size-exclusion chromatography, density gradient centrifugation, kit-based precipitation, electron microscopy, cryo-electron microscopy, flow cytometry, atomic-force microscopy and nanoparticle-tracking analysis are covered. This first massive open online course (MOOC) on EVs was launched on 15 August 2016 at the platform "Coursera" and is free of charge.

  5. Extracellular matrix in canine mammary tumors with special focus on versican, a versatile extracellular proteoglycan

    NARCIS (Netherlands)

    Erdélyi, Ildikó

    2006-01-01

    The extracellular matrix (ECM) research has become fundamental to understand cancer. This thesis focuses on the exploration of ECM composition and organization in canine mammary tumors, with a special interest in the large chondroitin-sulfate proteoglycan (PG), versican. Chapter 1 gives an

  6. The International Society for Extracellular Vesicles launches the first massive open online course on extracellular vesicles

    Directory of Open Access Journals (Sweden)

    Cecilia Lässer

    2016-12-01

    Full Text Available The International Society for Extracellular Vesicles (ISEV has organised its first educational online course for students and beginners in the field of extracellular vesicles (EVs. This course, “Basics of Extracellular Vesicles,” uses recorded lectures from experts in the field and will be open for an unlimited number of participants. The course is divided into 5 modules and can be accessed at www.coursera.org/learn/extracellular-vesicles. The first module is an introduction to the field covering the nomenclature and history of EVs. Module 2 focuses on the biogenesis and uptake mechanisms of EVs, as well as their RNA, protein and lipid cargo. Module 3 covers the collection and processing of cell culture media and body fluids such as blood, breast milk, cerebrospinal fluid and urine prior to isolation of EVs. Modules 4 and 5 present different isolation methods and characterisation techniques utilised in the EV field. Here, differential ultracentrifugation, size-exclusion chromatography, density gradient centrifugation, kit-based precipitation, electron microscopy, cryo-electron microscopy, flow cytometry, atomic-force microscopy and nanoparticle-tracking analysis are covered. This first massive open online course (MOOC on EVs was launched on 15 August 2016 at the platform “Coursera” and is free of charge.

  7. The Extracellular Matrix of Candida albicans Biofilms Impairs Formation of Neutrophil Extracellular Traps.

    Science.gov (United States)

    Johnson, Chad J; Cabezas-Olcoz, Jonathan; Kernien, John F; Wang, Steven X; Beebe, David J; Huttenlocher, Anna; Ansari, Hamayail; Nett, Jeniel E

    2016-09-01

    Neutrophils release extracellular traps (NETs) in response to planktonic C. albicans. These complexes composed of DNA, histones, and proteins inhibit Candida growth and dissemination. Considering the resilience of Candida biofilms to host defenses, we examined the neutrophil response to C. albicans during biofilm growth. In contrast to planktonic C. albicans, biofilms triggered negligible release of NETs. Time lapse imaging confirmed the impairment in NET release and revealed neutrophils adhering to hyphae and migrating on the biofilm. NET inhibition depended on an intact extracellular biofilm matrix as physical or genetic disruption of this component resulted in NET release. Biofilm inhibition of NETosis could not be overcome by protein kinase C activation via phorbol myristate acetate (PMA) and was associated with suppression of neutrophil reactive oxygen species (ROS) production. The degree of impaired NET release correlated with resistance to neutrophil attack. The clinical relevance of the role for extracellular matrix in diminishing NET production was corroborated in vivo using a rat catheter model. The C. albicans pmr1Δ/Δ, defective in production of matrix mannan, appeared to elicit a greater abundance of NETs by scanning electron microscopy imaging, which correlated with a decreased fungal burden. Together, these findings show that C. albicans biofilms impair neutrophil response through an inhibitory pathway induced by the extracellular matrix.

  8. Highly sensitive electrochemical biosensor for bisphenol A detection based on a diazonium-functionalized boron-doped diamond electrode modified with a multi-walled carbon nanotube-tyrosinase hybrid film.

    Science.gov (United States)

    Zehani, Nedjla; Fortgang, Philippe; Saddek Lachgar, Mohamed; Baraket, Abdoullatif; Arab, Madjid; Dzyadevych, Sergei V; Kherrat, Rochdi; Jaffrezic-Renault, Nicole

    2015-12-15

    A highly sensitive electrochemical biosensor for the detection of Bisphenol A (BPA) in water has been developed by immobilizing tyrosinase onto a diazonium-functionalized boron doped diamond electrode (BDD) modified with multi-walled carbon nanotubes (MWCNTs). The fabricated biosensor exhibits excellent electroactivity towards o-quinone, a product of this enzymatic reaction of BPA oxidation catalyzed by tyrosinase. The developed BPA biosensor displays a large linear range from 0.01 nM to 100 nM, with a detection limit (LOD) of 10 pM. The feasibility of the proposed biosensor has been demonstrated on BPA spiked water river samples. Therefore, it could be a promising and reliable analytical tool for on-site monitoring of BPA in waste water. Copyright © 2015 Elsevier B.V. All rights reserved.

  9. Stable isotope research pool inventory

    International Nuclear Information System (INIS)

    1980-12-01

    This report contains a listing of electromagnetically separated stable isotopes which are available for distribution within the United States for non-destructive research use from the Oak Ridge National Laboratory on a loan basis. This inventory includes all samples of stable isotopes in the Materials Research Collection and does not designate whether a sample is out on loan or in reprocessing

  10. Extracellular RNAs: development as biomarkers of human disease

    Directory of Open Access Journals (Sweden)

    Joseph F. Quinn

    2015-08-01

    Full Text Available Ten ongoing studies designed to test the possibility that extracellular RNAs may serve as biomarkers in human disease are described. These studies, funded by the NIH Common Fund Extracellular RNA Communication Program, examine diverse extracellular body fluids, including plasma, serum, urine and cerebrospinal fluid. The disorders studied include hepatic and gastric cancer, cardiovascular disease, chronic kidney disease, neurodegenerative disease, brain tumours, intracranial haemorrhage, multiple sclerosis and placental disorders. Progress to date and the plans for future studies are outlined.

  11. A Novel Molecular Diagnostic of Glioblastomas: Detection of an Extracellular Fragment of Protein Tyrosine Phosphatase μ

    Directory of Open Access Journals (Sweden)

    Susan M. Burden-Gulley

    2010-04-01

    Full Text Available We recently found that normal human brain and low-grade astrocytomas express the receptor protein tyrosine phosphatase mu (PTPμ and that the more invasive astrocytomas, glioblastoma multiforme (GBM, downregulate full-length PTPμ expression. Loss of PTPμ expression in GBMs is due to proteolytic cleavage that generates an intracellular and potentially a cleaved and released extracellular fragment of PTPμ. Here, we identify that a cleaved extracellular fragment containing the domains required for PTPμ-mediated adhesion remains associated with GBM tumor tissue. We hypothesized that detection of this fragment would make an excellent diagnostic tool for the localization of tumor tissue within the brain. To this end, we generated a series of fluorescently tagged peptide probes that bind the PTPμ fragment. The peptide probes specifically recognize GBM cells in tissue sections of surgically resected human tumors. To test whether the peptide probes are able to detect GBM tumors in vivo, the PTPμ peptide probes were tested in both mouse flank and intracranial xenograft human glioblastoma tumor model systems. The glial tumors were molecularly labeled with the PTPμ peptide probes within minutes of tail vein injection using the Maestro FLEX In Vivo Imaging System. The label was stable for at least 3 hours. Together, these results indicate that peptide recognition of the PTPμ extracellular fragment provides a novel molecular diagnostic tool for detection of human glioblastomas. Such a tool has clear translational applications and may lead to improved surgical resections and prognosis for patients with this devastating disease.

  12. Phytosynthesis of intracellular and extracellular gold nanoparticles by living peanut plant (Arachis hypogaea L.).

    Science.gov (United States)

    Raju, Dugyala; Mehta, Urmil J; Ahmad, Absar

    2012-01-01

    Inorganic nanomaterials of different chemical compositions are conventionally synthesized under harsh environments such as extremes of temperature, pressure, and pH. Moreover, these methods are eco-unfriendly and cumbersome, yield bigger particles, and agglomerate because of not being capped by capping agents. In contrast, biological synthesis of inorganic nanomaterials occurs under ambient conditions, namely room temperature, atmospheric pressure, and physiological pH. These methods are reliable, eco-friendly, and cheap. In this paper, we report for the first time the extracellular and intracellular synthesis of gold nanoparticles (GNPs) using living peanut seedlings. The formed GNPs were highly stable in solution and inside the plant tissue. Transmission electron microscopy revealed that extracellular GNPs distributions were in the form of monodispersed nanoparticles. The nanoparticles ranged from 4 to 6 nm in size. The intercellular nanoparticles were of oval shape and size ranged from 5 to 50 nm. Both extracellular and intracellular nanoparticles were further characterized by standard techniques. The formed GNPs inside the plant tissue were estimated by inductively coupled plasma spectrometry. This opens up an exciting possibility of a plant-based nanoparticle synthesis strategy, wherein the nanoparticles may be entrapped in the biomass in the form of a film or produced in the solution, both of which have interesting applications. © 2012 International Union of Biochemistry and Molecular Biology, Inc.

  13. Stable and sensitive flow-through monitoring of phenol using a carbon nanotube based screen printed biosensor

    International Nuclear Information System (INIS)

    Alarcon, G; Guix, M; Ambrosi, A; Merkoci, A; Ramirez Silva, M T; Palomar Pardave, M E

    2010-01-01

    A stable and sensitive biosensor for phenol detection based on a screen printed electrode modified with tyrosinase, multiwall carbon nanotubes and glutaraldehyde is designed and applied in a flow injection analytical system. The proposed carbon nanotube matrix is easy to prepare and ensures a very good entrapment environment for the enzyme, being simpler and cheaper than other reported strategies. In addition, the proposed matrix allows for a very fast operation of the enzyme, that leads to a response time of 15 s. Several parameters such as the working potential, pH of the measuring solution, biosensor response time, detection limit, linear range of response and sensitivity are studied. The obtained detection limit for phenol was 0.14 x 10 -6 M. The biosensor keeps its activity during continuous FIA measurements at room temperature, showing a stable response (RSD 5%) within a two week working period at room temperature. The developed biosensor is being applied for phenol detection in seawater samples and seems to be a promising alternative for automatic control of seawater contamination. The developed detection system can be extended to other enzyme biosensors with interest for several other applications.

  14. Stable and sensitive flow-through monitoring of phenol using a carbon nanotube based screen printed biosensor

    Energy Technology Data Exchange (ETDEWEB)

    Alarcon, G; Guix, M; Ambrosi, A; Merkoci, A [Nanobioelectronics and Biosensors Group, Catalan Institute of Nanotechnology, Campus UAB, 08193 Bellaterra, Barcelona, Catalonia (Spain); Ramirez Silva, M T [Departamento de Quimica, Universidad Autonoma Metropolitana Iztapalapa, 09340 Mexico Distrito Federal (Mexico); Palomar Pardave, M E, E-mail: arben.merkoci.icn@uab.es [Departamento de Materiales, Universidad Autonoma Metropolitana, Azcapotzalco, 02200 Mexico Distrito Federal (Mexico)

    2010-06-18

    A stable and sensitive biosensor for phenol detection based on a screen printed electrode modified with tyrosinase, multiwall carbon nanotubes and glutaraldehyde is designed and applied in a flow injection analytical system. The proposed carbon nanotube matrix is easy to prepare and ensures a very good entrapment environment for the enzyme, being simpler and cheaper than other reported strategies. In addition, the proposed matrix allows for a very fast operation of the enzyme, that leads to a response time of 15 s. Several parameters such as the working potential, pH of the measuring solution, biosensor response time, detection limit, linear range of response and sensitivity are studied. The obtained detection limit for phenol was 0.14 x 10{sup -6} M. The biosensor keeps its activity during continuous FIA measurements at room temperature, showing a stable response (RSD 5%) within a two week working period at room temperature. The developed biosensor is being applied for phenol detection in seawater samples and seems to be a promising alternative for automatic control of seawater contamination. The developed detection system can be extended to other enzyme biosensors with interest for several other applications.

  15. A perspective on extracellular vesicles proteomics

    Science.gov (United States)

    Rosa-Fernandes, Livia; Rocha, Victória Bombarda; Carregari, Victor Corasolla; Urbani, Andrea; Palmisano, Giuseppe

    2017-11-01

    Increasing attention has been given to secreted extracellular vesicles (EVs) in the past decades, especially in the portrayal of their molecular cargo and role as messengers in both homeostasis and pathophysiological conditions. This review presents the state-of-the-art proteomic technologies to identify and quantify EVs proteins along with their PTMs, interacting partners and structural details. The rapid growth of mass spectrometry-based analytical strategies for protein sequencing, PTMs and structural characterization has improved the level of molecular details that can be achieve from limited amount of EVs isolated from different biological sources. Here we will provide a perspective view on the achievements and challenges on EVs proteome characterization using mass spectrometry. A detailed bioinformatics approach will help us to picture the molecular fingerprint of EVs and understand better their pathophysiological function.

  16. Why regenerative medicine needs an extracellular matrix.

    Science.gov (United States)

    Prestwich, Glenn D; Healy, Kevin E

    2015-01-01

    Regenerative medicine is now coming of age. Many attempts at cell therapy have failed to show significant efficacy, and the umbrella term 'stem cell therapy' is perceived in some quarters as hype or just expensive and unnecessary medical tourism. Here we present a short editorial in three parts. First, we examine the importance of using a semisynthetic extracellular matrix (ECM) mimetic, or sECM, to deliver and retain therapeutic cells at the site of administration. Second, we describe one approach in which biophysical and biochemical properties are tailored to each tissue type, which we call "design for optimal functionality." Third, we describe an alternative approach to sECM design and implementation, called "design for simplicity," in which a deconstructed, minimalist sECM is employed and biology is allowed to perform the customization in situ. We opine that an sECM, whether minimal or instructive, is an essential contributor to improve the outcomes of cell-based therapies.

  17. Extracellular matrix fluctuations during early embryogenesis

    International Nuclear Information System (INIS)

    Szabó, A; Rupp, P A; Rongish, B J; Little, C D; Czirók, A

    2011-01-01

    Extracellular matrix (ECM) movements and rearrangements were studied in avian embryos during early stages of development. We show that the ECM moves as a composite material, whereby distinct molecular components as well as spatially separated layers exhibit similar displacements. Using scanning wide field and confocal microscopy we show that the velocity field of ECM displacement is smooth in space and that ECM movements are correlated even at locations separated by several hundred micrometers. Velocity vectors, however, strongly fluctuate in time. The autocorrelation time of the velocity fluctuations is less than a minute. Suppression of the fluctuations yields a persistent movement pattern that is shared among embryos at equivalent stages of development. The high resolution of the velocity fields allows a detailed spatio-temporal characterization of important morphogenetic processes, especially tissue dynamics surrounding the embryonic organizer (Hensen's node)

  18. Extracellular Matrix Molecules Facilitating Vascular Biointegration

    Directory of Open Access Journals (Sweden)

    Martin K.C. Ng

    2012-08-01

    Full Text Available All vascular implants, including stents, heart valves and graft materials exhibit suboptimal biocompatibility that significantly reduces their clinical efficacy. A range of biomolecules in the subendothelial space have been shown to play critical roles in local regulation of thrombosis, endothelial growth and smooth muscle cell proliferation, making these attractive candidates for modulation of vascular device biointegration. However, classically used biomaterial coatings, such as fibronectin and laminin, modulate only one of these components; enhancing endothelial cell attachment, but also activating platelets and triggering thrombosis. This review examines a subset of extracellular matrix molecules that have demonstrated multi-faceted vascular compatibility and accordingly are promising candidates to improve the biointegration of vascular biomaterials.

  19. Identification of a receptor for extracellular renalase.

    Directory of Open Access Journals (Sweden)

    Ling Wang

    Full Text Available An increased risk for developing essential hypertension, stroke and diabetes is associated with single nucleotide gene polymorphisms in renalase, a newly described secreted flavoprotein with oxidoreductase activity. Gene deletion causes hypertension, and aggravates acute ischemic kidney (AKI and cardiac injury. Independent of its intrinsic enzymatic activities, extracellular renalase activates MAPK signaling and prevents acute kidney injury (AKI in wild type (WT mice. Therefore, we sought to identity the receptor for extracellular renalase.RP-220 is a previously identified, 20 amino acids long renalase peptide that is devoid of any intrinsic enzymatic activity, but it is equally effective as full-length recombinant renalase at protecting against toxic and ischemic injury. Using biotin transfer studies with RP-220 in the human proximal tubular cell line HK-2 and protein identification by mass spectrometry, we identified PMCA4b as a renalase binding protein. This previously characterized plasma membrane ATPase is involved in cell signaling and cardiac hypertrophy. Co-immunoprecipitation and co-immunolocalization confirmed protein-protein interaction between endogenous renalase and PMCA4b. Down-regulation of endogenous PMCA4b expression by siRNA transfection, or inhibition of its enzymatic activity by the specific peptide inhibitor caloxin1b each abrogated RP-220 dependent MAPK signaling and cytoprotection. In control studies, these maneuvers had no effect on epidermal growth factor mediated signaling, confirming specificity of the interaction between PMCA4b and renalase.PMCA4b functions as a renalase receptor, and a key mediator of renalase dependent MAPK signaling.

  20. Stable configurations in social networks

    Science.gov (United States)

    Bronski, Jared C.; DeVille, Lee; Ferguson, Timothy; Livesay, Michael

    2018-06-01

    We present and analyze a model of opinion formation on an arbitrary network whose dynamics comes from a global energy function. We study the global and local minimizers of this energy, which we call stable opinion configurations, and describe the global minimizers under certain assumptions on the friendship graph. We show a surprising result that the number of stable configurations is not necessarily monotone in the strength of connection in the social network, i.e. the model sometimes supports more stable configurations when the interpersonal connections are made stronger.

  1. Development of Stable Isotope Technology

    International Nuclear Information System (INIS)

    Jeong, Do Young; Kim, Cheol Jung; Han, Jae Min

    2009-03-01

    KAERI has obtained an advanced technology with singular originality for laser stable isotope separation. Objectives for this project are to get production technology of Tl-203 stable isotope used for medical application and are to establish the foundation of the pilot system, while we are taking aim at 'Laser Isotope Separation Technology to make resistance to the nuclear proliferation'. And we will contribute to ensuring a nuclear transparency in the world society by taking part in a practical group of NSG and being collaboration with various international groups related to stable isotope separation technology

  2. In vivo EPR extracellular pH-metry in tumors using a triphosphonated trityl radical.

    Science.gov (United States)

    Marchand, Valérie; Levêque, Philippe; Driesschaert, Benoit; Marchand-Brynaert, Jacqueline; Gallez, Bernard

    2017-06-01

    The ability to assess the extracellular pH (pHe) is an important issue in oncology, because extracellular acidification is associated with tumor aggressiveness and resistance to cytotoxic therapies. In this study, a stable triphosphonated triarylmethyl (TPTAM) radical was qualified as a pHe electron paramagnetic resonance (EPR) molecular reporter. Calibration of hyperfine splitting as a function of pH was performed using a 1.2-GHz EPR spectrometer. Gadolinium-diethylenetriamine pentaacetic acid (Gd-DTPA) was used as an extracellular paramagnetic broadening agent to assess the localization of TPTAM when incubated with cells. In vivo EPR pH-metry was performed in MDA, SiHa, and TLT tumor models and in muscle. Bicarbonate therapy was used to modulate the tumor pHe. EPR measurements were compared with microelectrode readouts. The hyperfine splitting of TPTAM was strongly pH-dependent around the pKa of the probe (pKa = 6.99). Experiments with Gd-DTPA demonstrated that TPTAM remained in the extracellular compartment. pHe was found to be more acidic in the MDA, SiHa, and TLT tumor models compared with muscle. Treatment of animals by bicarbonate induced an increase in pHe in tumors: similar variations in pHe were found when using in vivo EPR or invasive microelectrodes measurements. This study demonstrates the potential usefulness of TPTAM for monitoring pHe in tumors. Magn Reson Med 77:2438-2443, 2017. © 2016 International Society for Magnetic Resonance in Medicine. © 2016 International Society for Magnetic Resonance in Medicine.

  3. Incorporation of Tenascin-C into the Extracellular Matrix by Periostin Underlies an Extracellular Meshwork Architecture*

    OpenAIRE

    Kii, Isao; Nishiyama, Takashi; Li, Minqi; Matsumoto, Ken-ichi; Saito, Mitsuru; Amizuka, Norio; Kudo, Akira

    2009-01-01

    Extracellular matrix (ECM) underlies a complicated multicellular architecture that is subjected to significant forces from mechanical environment. Although various components of the ECM have been enumerated, mechanisms that evolve the sophisticated ECM architecture remain to be addressed. Here we show that periostin, a matricellular protein, promotes incorporation of tenascin-C into the ECM and organizes a meshwork architecture of the ECM. We found that both periostin null mice and tenascin-C...

  4. Stable isotope research pool inventory

    International Nuclear Information System (INIS)

    1984-03-01

    This report contains a listing of electromagnetically separated stable isotopes which are available at the Oak Ridge National Laboratory for distribution for nondestructive research use on a loan basis. This inventory includes all samples of stable isotopes in the Research Materials Collection and does not designate whether a sample is out on loan or is in reprocessing. For some of the high abundance naturally occurring isotopes, larger amounts can be made available; for example, Ca-40 and Fe-56

  5. French days on stable isotopes

    International Nuclear Information System (INIS)

    2000-01-01

    These first French days on stable isotopes took place in parallel with the 1. French days of environmental chemistry. Both conferences had common plenary sessions. The conference covers all aspects of the use of stable isotopes in the following domains: medicine, biology, environment, tracer techniques, agronomy, food industry, geology, petroleum geochemistry, cosmo-geochemistry, archaeology, bio-geochemistry, hydrology, climatology, nuclear and particle physics, astrophysics, isotope separations etc.. Abstracts available on CD-Rom only. (J.S.)

  6. Stable isotope research pool inventory

    International Nuclear Information System (INIS)

    1982-01-01

    This report contains a listing of electromagnetically separated stable isotopes which are available for distribution within the United States for nondestructive research use from the Oak Ridge National Laboratory on a loan basis. This inventory includes all samples of stable isotopes in the Material Research Collection and does not designate whether a sample is out on loan or in reprocessing. For some of the high abundance naturally occurring isotopes, larger amounts can be made available; for example, Ca-40 and Fe-56

  7. Pharmaceuticals labelled with stable isotopes

    International Nuclear Information System (INIS)

    Krumbiegel, P.

    1986-11-01

    The relatively new field of pharmaceuticals labelled with stable isotopes is reviewed. Scientific, juridical, and ethical questions are discussed concerning the application of these pharmaceuticals in human medicine. 13 C, 15 N, and 2 H are the stable isotopes mainly utilized in metabolic function tests. Methodical contributions are given to the application of 2 H, 13 C, and 15 N pharmaceuticals showing new aspects and different states of development in the field under discussion. (author)

  8. Dimensional characterization of extracellular vesicles using atomic force microscopy

    International Nuclear Information System (INIS)

    Sebaihi, N; De Boeck, B; Pétry, J; Yuana, Y; Nieuwland, R

    2017-01-01

    Extracellular vesicles (EV) are small biological entities released from cells into body fluids. EV are recognized as mediators in intercellular communication and influence important physiological processes. It has been shown that the concentration and composition of EV in body fluids may differ from healthy subjects to patients suffering from particular disease. So, EV have gained a strong scientific and clinical interest as potential biomarkers for diagnosis and prognosis of disease. Due to their small size, accurate detection and characterization of EV remain challenging. The aim of the presented work is to propose a characterization method of erythrocyte-derived EV using atomic force microscopy (AFM). The vesicles are immobilized on anti-CD235a-modified mica and analyzed by AFM under buffer liquid and dry conditions. EV detected under both conditions show very similar sizes namely ∼30 nm high and ∼90 nm wide. The size of these vesicles remains stable over drying time as long as 7 d at room temperature. Since the detected vesicles are not spherical, EV are characterized by their height and diameter, and not only by the height as is usually done for spherical nanoparticles. In order to obtain an accurate measurement of EV diameters, the geometry of the AFM tip was evaluated to account for the lateral broadening artifact inherent to AFM measurements. To do so, spherical polystyrene (PS) nanobeads and EV were concomitantly deposited on the same mica substrate and simultaneously measured by AFM under dry conditions. By applying this procedure, direct calibration of the AFM tip could be performed together with EV characterization under identical experimental conditions minimizing external sources of uncertainty on the shape and size of the tip, thus allowing standardization of EV measurement. (paper)

  9. Neutrophil extracellular traps - the dark side of neutrophils

    DEFF Research Database (Denmark)

    Sørensen, Ole E.; Borregaard, Niels

    2016-01-01

    Neutrophil extracellular traps (NETs) were discovered as extracellular strands of decondensed DNA in complex with histones and granule proteins, which were expelled from dying neutrophils to ensnare and kill microbes. NETs are formed during infection in vivo by mechanisms different from those ori...

  10. Production of extracellular laccase from the newly isolated Bacillus ...

    African Journals Online (AJOL)

    This study was carried out with aim of screening for extracellular thermostable laccase producing bacteria. Twenty-two (22) laccase positive strains were isolated from the selected environmental samples while extracellular laccase activity was detected only in six strains namely TM1, TMT1, PK4, PS1, TMS1 and ASP3.

  11. Immobilization of Tyrosinase on (3-Aminopropyltriethoxysilane-Functionalized Carbon Felt-Based Flow-Through Detectors for Electrochemical Detection of Phenolic Compounds

    Directory of Open Access Journals (Sweden)

    Zheng Zhou

    2017-07-01

    Full Text Available Tyrosinase (TYR was covalently immobilized onto amino-functionalized carbon felt (CF surface via glutaraldehyde (GA. Prior to the TYR-immobilization, primary amino group was introduced to the CF surface by treatment with 3-aminopropyltriethoxysilane (APTES. The resulting TYR-immobilized CF was used as a working electrode unit of an electrochemical flow-through detector for mono- and di-phenolic compounds (i.e., catechol, p-cresol, phenol and p-chlorophenol. Additionally, flow injection peaks based on electroreduction of the enzymatically produced o-quinone species were detected at −0.05 V vs. Ag/AgCl. The resulting TYR/GA/APTES/CF biosensor responded well to all compounds tested with limits of detection range from 7.5 to 35 nmol−1 (based on three times S/N ratio. Moreover, such modified electrode exhibits good stability and reproducibility for catechol. No serious degradation of the peak current was found over 30 consecutive injections.

  12. Aspergillus niger PA2 Tyrosinase Covalently Immobilized on a Novel Eco-Friendly Bio-Composite of Chitosan-Gelatin and Its Evaluation for L-DOPA Production

    Science.gov (United States)

    Agarwal, Pragati; Dubey, Swati; Singh, Mukta; Singh, Rajesh P.

    2016-01-01

    Tyrosinase (EC 1.14.18.1) a copper-containing monooxygenase, isolated from a fungal isolate Aspergillus niger PA2 was subjected for immobilization onto a composite consisting of chitosan and gelatin biopolymers. The homogeneity of the chitosan-gelatin biocomposite film was characterized by X-ray diffraction analyses. To evaluate immobilization efficiency, chitosan-gelatin-Tyr bio-composite films were analyzed by field emission scanning electron microscopy, atomic force microscopy and UV-spectroscopy. The rough morphology of the film led to a high loading of enzyme and it could retain its bioactivity for a longer period. The enzyme adsorbed onto the film exhibited 72% of its activity after 10 days and exhibited good repeatability for up to nine times, after intermittent storage. Moreover, the immobilized enzyme exhibited broader pH and temperature profile as compared to free counterpart. Immobilized enzyme was further evaluated for the synthesis of L-DOPA (2,4-dihydroxy phenylalanine) which is a precursor of dopamine and a potent drug for the treatment of Parkinson's disease and for myocardium neurogenic injury. PMID:28066399

  13. Amperometric biosensor for bisphenol A based on a glassy carbon electrode modified with a nanocomposite made from polylysine, single walled carbon nanotubes and tyrosinase

    International Nuclear Information System (INIS)

    Han, Miao; Qu, Ying; Chen, Shiqin; Wang, Yali; Zhang, Zhi; Zhan, Guoqing; Li, Chunya; Ma, Ming; Wang, Zhengguo

    2013-01-01

    We have prepared a nanocomposite consisting of single-walled carbon nanotubes and polylysine. It was characterized by transmission electron microscopy, X-ray photoelectron spectroscopy, and by UV/vis and FTIR spectroscopy. Tyrosinase was covalently immobilized on the nanocomposite, and the resulting bioconjugate deposited on a glassy carbon electrode to form a biosensor for bisphenol A. The biosensor was characterized by scanning electron microscopy and electrochemical impedance spectroscopy. Under optimized experimental conditions, the biosensor gives a linear response to bisphenol A in the 4.00 nM to 11.5 μM concentration range. Its sensitivity is 788 mA M −1 cm −2 , and the lower detection limit is 0.97 nM (at an S/N of 3). The biosensor shows good repeatability, reproducibility and long-term stability. In a preliminary practical application, it was successfully applied to the determination of bisphenol A in leachates of plastic spoons. (author)

  14. Safety and efficacy of a xenogeneic DNA vaccine encoding for human tyrosinase as adjunctive treatment for oral malignant melanoma in dogs following surgical excision of the primary tumor.

    Science.gov (United States)

    Grosenbaugh, Deborah A; Leard, A Timothy; Bergman, Philip J; Klein, Mary K; Meleo, Karri; Susaneck, Steven; Hess, Paul R; Jankowski, Monika K; Jones, Pamela D; Leibman, Nicole F; Johnson, Maribeth H; Kurzman, Ilene D; Wolchok, Jedd D

    2011-12-01

    To evaluate the safety and efficacy of a vaccine containing plasmid DNA with an insert encoding human tyrosinase (ie, huTyr vaccine) as adjunctive treatment for oral malignant melanoma (MM) in dogs. 111 dogs (58 prospectively enrolled in a multicenter clinical trial and 53 historical controls) with stage II or III oral MM (modified World Health Organization staging scale, I to IV) in which locoregional disease control was achieved. 58 dogs received an initial series of 4 injections of huTyr vaccine (102 μg of DNA/injection) administered transdermally by use of a needle-free IM vaccination device. Dogs were monitored for adverse reactions. Surviving dogs received booster injections at 6-month intervals thereafter. Survival time for vaccinates was compared with that of historical control dogs via Kaplan-Meier survival analysis for the outcome of death. Kaplan-Meier analysis of survival time until death attributable to MM was determined to be significantly improved for dogs that received the huTyr vaccine, compared with that of historical controls. However, median survival time could not be determined for vaccinates because dogs as adjunctive treatment for oral MM. Response to DNA vaccination in dogs with oral MM may be useful in development of plasmid DNA vaccination protocols for human patients with similar disease.

  15. Investigating wound healing, tyrosinase inhibitory and antioxidant activities of the ethanol extracts of Salvia cryptantha and Salvia cyanescens using in vivo and in vitro experimental models.

    Science.gov (United States)

    Süntar, Ipek; Akkol, Esra Küpeli; Senol, Fatma Sezer; Keles, Hikmet; Orhan, Ilkay Erdogan

    2011-04-26

    Salvia L. species are widely used against wounds and skin infections in Turkish folk medicine. The aim of the present study is to evaluate wound healing activity of the ethanol (EtOH) extracts of Salvia cryptantha and Salvia cyanescens. For the assessment of wound healing activity linear incision and circular excision wound models were employed on rats and mice. The wound healing effect was comparatively evaluated with the standard skin ointment Madecassol(®). Inhibition of tyrosinase, a key enzyme in skin aging, was achieved using ELISA microplate reader. Antioxidant activity was evaluated by 2,2-diphenyl-1-picrylhydrazyl (DPPH) and superoxide radical scavenger effect, ferrous ion-chelating ability, and ferric-reducing antioxidant power (FRAP) tests. The EtOH extract of Salvia cryptantha treated groups of animals showed 56.5% contraction, whereas the reference drug Madecassol(®) showed 100% contraction. On the other hand, the same extract on linear incision wound model demonstrated a significant increase (33.2%) in wound tensile strength as compared to other groups. The results of histopathological examination maintained the upshot of linear incision and circular excision wound models as well. These findings specify that Salvia cryptantha for wound healing activity can be appealed further phytochemical estimation for spotting its active components. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

  16. Extracellular matrix dynamics during vertebrate axis formation.

    Science.gov (United States)

    Czirók, András; Rongish, Brenda J; Little, Charles D

    2004-04-01

    The first evidence for the dynamics of in vivo extracellular matrix (ECM) pattern formation during embryogenesis is presented below. Fibrillin 2 filaments were tracked for 12 h throughout the avian intraembryonic mesoderm using automated light microscopy and algorithms of our design. The data show that these ECM filaments have a reproducible morphogenic destiny that is characterized by directed transport. Fibrillin 2 particles initially deposited in the segmental plate mesoderm are translocated along an unexpected trajectory where they eventually polymerize into an intricate scaffold of cables parallel to the anterior-posterior axis. The cables coalesce near the midline before the appearance of the next-formed somite. Moreover, the ECM filaments define global tissue movements with high precision because the filaments act as passive motion tracers. Quantification of individual and collective filament "behaviors" establish fate maps, trajectories, and velocities. These data reveal a caudally propagating traveling wave pattern in the morphogenetic movements of early axis formation. We conjecture that within vertebrate embryos, long-range mechanical tension fields are coupled to both large-scale patterning and local organization of the ECM. Thus, physical forces or stress fields are essential requirements for executing an emergent developmental pattern-in this case, paraxial fibrillin cable assembly.

  17. Extracellular ice phase transitions in insects.

    Science.gov (United States)

    Hawes, T C

    2014-01-01

    At temperatures below their temperature of crystallization (Tc), the extracellular body fluids of insects undergo a phase transition from liquid to solid. Insects that survive the transition to equilibrium (complete freezing of the body fluids) are designated as freeze tolerant. Although this phenomenon has been reported and described in many Insecta, current nomenclature and theory does not clearly delineate between the process of transition (freezing) and the final solid phase itself (the frozen state). Thus freeze tolerant insects are currently, by convention, described in terms of the temperature at which the crystallization of their body fluids is initiated, Tc. In fact, the correct descriptor for insects that tolerate freezing is the temperature of equilibrium freezing, Tef. The process of freezing is itself a separate physical event with unique physiological stresses that are associated with ice growth. Correspondingly there are a number of insects whose physiological cryo-limits are very specifically delineated by this transitional envelope. The distinction also has considerable significance for our understanding of insect cryobiology: firstly, because the ability to manage endogenous ice growth is a fundamental segregator of cryotype; and secondly, because our understanding of internal ice management is still largely nascent.

  18. Towards traceable size determination of extracellular vesicles

    Directory of Open Access Journals (Sweden)

    Zoltán Varga

    2014-02-01

    Full Text Available Background: Extracellular vesicles (EVs have clinical importance due to their roles in a wide range of biological processes. The detection and characterization of EVs are challenging because of their small size, low refractive index, and heterogeneity. Methods: In this manuscript, the size distribution of an erythrocyte-derived EV sample is determined using state-of-the-art techniques such as nanoparticle tracking analysis, resistive pulse sensing, and electron microscopy, and novel techniques in the field, such as small-angle X-ray scattering (SAXS and size exclusion chromatography coupled with dynamic light scattering detection. Results: The mode values of the size distributions of the studied erythrocyte EVs reported by the different methods show only small deviations around 130 nm, but there are differences in the widths of the size distributions. Conclusion: SAXS is a promising technique with respect to traceability, as this technique was already applied for traceable size determination of solid nanoparticles in suspension. To reach the traceable measurement of EVs, monodisperse and highly concentrated samples are required.

  19. Tumorigenic Potential of Extracellular Matrix Metalloproteinase Inducer

    Science.gov (United States)

    Zucker, Stanley; Hymowitz, Michelle; Rollo, Ellen E.; Mann, Richard; Conner, Cathleen E.; Cao, Jian; Foda, Hussein D.; Tompkins, David C.; Toole, Bryan P.

    2001-01-01

    Extracellular matrix metalloproteinase inducer (EMMPRIN), a glycoprotein present on the cancer cell plasma membrane, enhances fibroblast synthesis of matrix metalloproteinases (MMPs). The demonstration that peritumoral fibroblasts synthesize most of the MMPs in human tumors rather than the cancer cells themselves has ignited interest in the role of EMMPRIN in tumor dissemination. In this report we have demonstrated a role for EMMPRIN in cancer progression. Human MDA-MB-436 breast cancer cells, which are tumorigenic but slow growing in vivo, were transfected with EMMPRIN cDNA and injected orthotopically into mammary tissue of female NCr nu/nu mice. Green fluorescent protein was used to visualize metastases. In three experiments, breast cancer cell clones transfected with EMMPRIN cDNA were considerably more tumorigenic and invasive than plasmid-transfected cancer cells. Increased gelatinase A and gelatinase B expression (demonstrated by in situ hybridization and gelatin substrate zymography) was demonstrated in EMMPRIN-enhanced tumors. In contrast to de novo breast cancers in humans, human tumors transplanted into mice elicited minimal stromal or inflammatory cell reactions. Based on these experimental studies and our previous demonstration that EMMPRIN is prominently displayed in human cancer tissue, we propose that EMMPRIN plays an important role in cancer progression by increasing synthesis of MMPs. PMID:11395366

  20. New extracellular resistance mechanism for cisplatin.

    Science.gov (United States)

    Centerwall, Corey R; Kerwood, Deborah J; Goodisman, Jerry; Toms, Bonnie B; Dabrowiak, James C

    2008-01-01

    The HSQC NMR spectrum of 15N-cisplatin in cell growth media shows resonances corresponding to the monocarbonato complex, cis-[Pt(NH3)2(CO3)Cl](-), 4, and the dicarbonato complex, cis-[Pt(NH3)2(CO3)2](-2), 5, in addition to cisplatin itself, cis-[Pt(NH3)2Cl2], 1. The presence of Jurkat cells reduces the amount of detectable carbonato species by (2.8+/-0.7) fmol per cell and has little effect on species 1. Jurkat cells made resistant to cisplatin reduce the amount of detectable carbonato species by (7.9+/-5.6) fmol per cell and also reduce the amount of 1 by (3.4+/-0.9) fmol per cell. The amount of detectable carbonato species is also reduced by addition of the drug to medium that has previously been in contact with normal Jurkat cells (cells removed); the reduction is greater when drug is added to medium previously in contact with resistant Jurkat cells (cells removed). This shows that the platinum species are modified by a cell-produced substance that is released to the medium. Since the modified species have been shown not to enter or bind to cells, and since resistant cells modify more than non-resistant cells, the modification constitutes a new extracellular mechanism for cisplatin resistance which merits further attention.

  1. Relevance of extracellular DNA in rhizosphere

    Science.gov (United States)

    Pietramellara, Giacomo; Ascher, Judith; Baraniya, Divyashri; Arfaioli, Paola; Ceccherini, Maria Teresa; Hawes, Martha

    2013-04-01

    One of the most promising areas for future development is the manipulation of the rhizosphere to produce sustainable and efficient agriculture production systems. Using Omics approaches, to define the distinctive features of eDNA systems and structures, will facilitate progress in rhizo-enforcement and biocontrol studies. The relevance of these studies results clear when we consider the plethora of ecological functions in which eDNA is involved. This fraction can be actively extruded by living cells or discharged during cellular lysis and may exert a key role in the stability and variability of the soil bacterial genome, resulting also a source of nitrogen and phosphorus for plants due to the root's capacity to directly uptake short DNA fragments. The adhesive properties of the DNA molecule confer to eDNA the capacity to inhibit or kill pathogenic bacteria by cation limitation induction, and to facilitate formation of biofilm and extracellular traps (ETs), that may protect microorganisms inhabiting biofilm and plant roots against pathogens and allelopathic substances. The ETs are actively extruded by root border cells when they are dispersed in the rhizosphere, conferring to plants the capacity to extend an endogenous pathogen defence system outside the organism. Moreover, eDNA could be involved in rhizoremediation in heavy metal polluted soil acting as a bioflotation reagent.

  2. Functional transferred DNA within extracellular vesicles

    International Nuclear Information System (INIS)

    Cai, Jin; Wu, Gengze; Jose, Pedro A.; Zeng, Chunyu

    2016-01-01

    Extracellular vesicles (EVs) are small membrane vesicles including exosomes and shedding vesicles that mediated a cell-to-cell communication. EVs are released from almost all cell types under both physiological and pathological conditions and incorporate nuclear and cytoplasmic molecules for intercellular delivery. Besides protein, mRNA, and microRNA of these molecules, as recent studies show, specific DNA are prominently packaged into EVs. It appears likely that some of exosomes or shedding vesicles, bearing nuclear molecules are released upon bubble-like blebs. Specific interaction of EVs with susceptible recipients performs the uptake of EVs into the target cells, discharging their cargo including nuclear and cytoplasmic macromolecules into the cytosol. These findings expand the nucleic acid content of EVs to include increased levels of specific DNA. Thus, EVs contain a repertoire of genetic information available for horizontal gene transfer and potential use as blood biomarkers for cancer and atherosclerosis. In this review, the focus is on the characteristics, biological functions, and roles in diseases of DNA within EVs. - Highlights: • This review is focused on the DNA within EVs including its characteristics, biological functions, and roles in diseases. • It is clear that DNA within EVs might have important physiological and pathological roles in various diseases. • Knowledge in this area may provides us alternative methods for disease diagnosis or therapy in the future.

  3. Extracellular small RNAs: what, where, why?

    Science.gov (United States)

    Hoy, Anna M.; Buck, Amy H.

    2012-01-01

    miRNAs (microRNAs) are a class of small RNA that regulate gene expression by binding to mRNAs and modulating the precise amount of proteins that get expressed in a cell at a given time. This form of gene regulation plays an important role in developmental systems and is critical for the proper function of numerous biological pathways. Although miRNAs exert their functions inside the cell, these and other classes of RNA are found in body fluids in a cell-free form that is resistant to degradation by RNases. A broad range of cell types have also been shown to secrete miRNAs in association with components of the RISC (RNA-induced silencing complex) and/or encapsulation within vesicles, which can be taken up by other cells. In the present paper, we provide an overview of the properties of extracellular miRNAs in relation to their capacity as biomarkers, stability against degradation and mediators of cell–cell communication. PMID:22817753

  4. Peroxidase enzymes regulate collagen extracellular matrix biosynthesis.

    Science.gov (United States)

    DeNichilo, Mark O; Panagopoulos, Vasilios; Rayner, Timothy E; Borowicz, Romana A; Greenwood, John E; Evdokiou, Andreas

    2015-05-01

    Myeloperoxidase and eosinophil peroxidase are heme-containing enzymes often physically associated with fibrotic tissue and cancer in various organs, without any direct involvement in promoting fibroblast recruitment and extracellular matrix (ECM) biosynthesis at these sites. We report herein novel findings that show peroxidase enzymes possess a well-conserved profibrogenic capacity to stimulate the migration of fibroblastic cells and promote their ability to secrete collagenous proteins to generate a functional ECM both in vitro and in vivo. Mechanistic studies conducted using cultured fibroblasts show that these cells are capable of rapidly binding and internalizing both myeloperoxidase and eosinophil peroxidase. Peroxidase enzymes stimulate collagen biosynthesis at a post-translational level in a prolyl 4-hydroxylase-dependent manner that does not require ascorbic acid. This response was blocked by the irreversible myeloperoxidase inhibitor 4-amino-benzoic acid hydrazide, indicating peroxidase catalytic activity is essential for collagen biosynthesis. These results suggest that peroxidase enzymes, such as myeloperoxidase and eosinophil peroxidase, may play a fundamental role in regulating the recruitment of fibroblast and the biosynthesis of collagen ECM at sites of normal tissue repair and fibrosis, with enormous implications for many disease states where infiltrating inflammatory cells deposit peroxidases. Copyright © 2015 American Society for Investigative Pathology. Published by Elsevier Inc. All rights reserved.

  5. Functional transferred DNA within extracellular vesicles

    Energy Technology Data Exchange (ETDEWEB)

    Cai, Jin [Department of Cardiology, Daping Hospital, The Third Military Medical University, Chongqing 400042 (China); Department of Neurology, Jinling Hospital, Nanjing University School of Medicine, Jiangsu Province (China); Wu, Gengze [Department of Cardiology, Daping Hospital, The Third Military Medical University, Chongqing 400042 (China); Jose, Pedro A. [Division of Nephrology, Department of Medicine and Physiology, University of Maryland, School of Medicine, Baltimore, MD 21201 (United States); Zeng, Chunyu, E-mail: Chunyuzeng01@163.com [Department of Cardiology, Daping Hospital, The Third Military Medical University, Chongqing 400042 (China)

    2016-11-15

    Extracellular vesicles (EVs) are small membrane vesicles including exosomes and shedding vesicles that mediated a cell-to-cell communication. EVs are released from almost all cell types under both physiological and pathological conditions and incorporate nuclear and cytoplasmic molecules for intercellular delivery. Besides protein, mRNA, and microRNA of these molecules, as recent studies show, specific DNA are prominently packaged into EVs. It appears likely that some of exosomes or shedding vesicles, bearing nuclear molecules are released upon bubble-like blebs. Specific interaction of EVs with susceptible recipients performs the uptake of EVs into the target cells, discharging their cargo including nuclear and cytoplasmic macromolecules into the cytosol. These findings expand the nucleic acid content of EVs to include increased levels of specific DNA. Thus, EVs contain a repertoire of genetic information available for horizontal gene transfer and potential use as blood biomarkers for cancer and atherosclerosis. In this review, the focus is on the characteristics, biological functions, and roles in diseases of DNA within EVs. - Highlights: • This review is focused on the DNA within EVs including its characteristics, biological functions, and roles in diseases. • It is clear that DNA within EVs might have important physiological and pathological roles in various diseases. • Knowledge in this area may provides us alternative methods for disease diagnosis or therapy in the future.

  6. Towards integrating extracellular matrix and immunological pathways.

    Science.gov (United States)

    Boyd, David F; Thomas, Paul G

    2017-10-01

    The extracellular matrix (ECM) is a complex and dynamic structure made up of an estimated 300 different proteins. The ECM is also a rich source of cytokines and growth factors in addition to numerous bioactive ECM degradation products that influence cell migration, proliferation, and differentiation. The ECM is constantly being remodeled during homeostasis and in a wide range of pathological contexts. Changes in the ECM modulate immune responses, which in turn regulate repair and regeneration of tissues. Here, we review the many components of the ECM, enzymes involved in ECM remodeling, and the signals that feed into immunological pathways in the context of a dynamic ECM. We highlight studies that have taken an integrative approach to studying immune responses in the context of the ECM and studies that use novel proteomic strategies. Finally, we discuss research challenges relevant to the integration of immune and ECM networks and propose experimental and translational approaches to resolve these issues. Copyright © 2017 Elsevier Ltd. All rights reserved.

  7. Force spectroscopy of hepatocytic extracellular matrix components

    Energy Technology Data Exchange (ETDEWEB)

    Yongsunthon, R., E-mail: YongsuntR@Corning.com [Corning Incorporated, SP-FR-01, R1S32D, Corning, NY 14831 (United States); Baker, W.A.; Bryhan, M.D.; Baker, D.E.; Chang, T.; Petzold, O.N.; Walczak, W.J.; Liu, J.; Faris, R.A.; Senaratne, W.; Seeley, L.A.; Youngman, R.E. [Corning Incorporated, SP-FR-01, R1S32D, Corning, NY 14831 (United States)

    2009-07-15

    We present atomic force microscopy and force spectroscopy data of live hepatocytes (HEPG2/C3A liver cell line) grown in Eagle's Minimum Essential Medium, a complex solution of salts and amino acids commonly used for cell culture. Contact-mode imaging and force spectroscopy of this system allowed correlation of cell morphology and extracellular matrix (ECM) properties with substrate properties. Force spectroscopy analysis of cellular 'footprints' indicated that the cells secrete large polymers (e.g., 3.5 {mu}m contour length and estimated MW 1000 kDa) onto their substrate surface. Although definitive identification of the polymers has not yet been achieved, fluorescent-labeled antibody staining has specified the presence of ECM proteins such as collagen and laminin in the cellular footprints. The stretched polymers appear to be much larger than single molecules of known ECM components, such as collagen and heparan sulfate proteoglycan, thus suggesting that the cells create larger entangled, macromolecular structures from smaller components. There is strong evidence which suggests that the composition of the ECM is greatly influenced by the hydrophobicity of the substrate surface, with preferential production and/or adsorption of larger macromolecules on hydrophobic surfaces.

  8. Routes and mechanisms of extracellular vesicle uptake

    Directory of Open Access Journals (Sweden)

    Laura Ann Mulcahy

    2014-08-01

    Full Text Available Extracellular vesicles (EVs are small vesicles released by donor cells that can be taken up by recipient cells. Despite their discovery decades ago, it has only recently become apparent that EVs play an important role in cell-to-cell communication. EVs can carry a range of nucleic acids and proteins which can have a significant impact on the phenotype of the recipient. For this phenotypic effect to occur, EVs need to fuse with target cell membranes, either directly with the plasma membrane or with the endosomal membrane after endocytic uptake. EVs are of therapeutic interest because they are deregulated in diseases such as cancer and they could be harnessed to deliver drugs to target cells. It is therefore important to understand the molecular mechanisms by which EVs are taken up into cells. This comprehensive review summarizes current knowledge of EV uptake mechanisms. Cells appear to take up EVs by a variety of endocytic pathways, including clathrin-dependent endocytosis, and clathrin-independent pathways such as caveolin-mediated uptake, macropinocytosis, phagocytosis, and lipid raft–mediated internalization. Indeed, it seems likely that a heterogeneous population of EVs may gain entry into a cell via more than one route. The uptake mechanism used by a given EV may depend on proteins and glycoproteins found on the surface of both the vesicle and the target cell. Further research is needed to understand the precise rules that underpin EV entry into cells.

  9. Protein Dynamics in the Plant Extracellular Space

    Directory of Open Access Journals (Sweden)

    Leonor Guerra-Guimarães

    2016-07-01

    Full Text Available The extracellular space (ECS or apoplast is the plant cell compartment external to the plasma membrane, which includes the cell walls, the intercellular space and the apoplastic fluid (APF. The present review is focused on APF proteomics papers and intends to draw information on the metabolic processes occurring in the ECS under abiotic and biotic stresses, as well as under non-challenged conditions. The large majority of the proteins detected are involved in “cell wall organization and biogenesis”, “response to stimulus” and “protein metabolism”. It becomes apparent that some proteins are always detected, irrespective of the experimental conditions, although with different relative contribution. This fact suggests that non-challenged plants have intrinsic constitutive metabolic processes of stress/defense in the ECS. In addition to the multiple functions ascribed to the ECS proteins, should be considered the interactions established between themselves and with the plasma membrane and its components. These interactions are crucial in connecting exterior and interior of the cell, and even simple protein actions in the ECS can have profound effects on plant performance. The proteins of the ECS are permanently contributing to the high dynamic nature of this plant compartment, which seems fundamental to plant development and adaptation to the environmental conditions.

  10. Bacterial Extracellular Polysaccharides Involved in Biofilm Formation

    Directory of Open Access Journals (Sweden)

    Elena P. Ivanova

    2009-07-01

    Full Text Available Extracellular polymeric substances (EPS produced by microorganisms are a complex mixture of biopolymers primarily consisting of polysaccharides, as well as proteins, nucleic acids, lipids and humic substances. EPS make up the intercellular space of microbial aggregates and form the structure and architecture of the biofilm matrix. The key functions of EPS comprise the mediation of the initial attachment of cells to different substrata and protection against environmental stress and dehydration. The aim of this review is to present a summary of the current status of the research into the role of EPS in bacterial attachment followed by biofilm formation. The latter has a profound impact on an array of biomedical, biotechnology and industrial fields including pharmaceutical and surgical applications, food engineering, bioremediation and biohydrometallurgy. The diverse structural variations of EPS produced by bacteria of different taxonomic lineages, together with examples of biotechnological applications, are discussed. Finally, a range of novel techniques that can be used in studies involving biofilm-specific polysaccharides is discussed.

  11. Activation of retinal glial (Müller cells by extracellular ATP induces pronounced increases in extracellular H+ flux.

    Directory of Open Access Journals (Sweden)

    Boriana K Tchernookova

    Full Text Available Small alterations in extracellular acidity are potentially important modulators of neuronal signaling within the vertebrate retina. Here we report a novel extracellular acidification mechanism mediated by glial cells in the retina. Using self-referencing H+-selective microelectrodes to measure extracellular H+ fluxes, we show that activation of retinal Müller (glial cells of the tiger salamander by micromolar concentrations of extracellular ATP induces a pronounced extracellular H+ flux independent of bicarbonate transport. ADP, UTP and the non-hydrolyzable analog ATPγs at micromolar concentrations were also potent stimulators of extracellular H+ fluxes, but adenosine was not. The extracellular H+ fluxes induced by ATP were mimicked by the P2Y1 agonist MRS 2365 and were significantly reduced by the P2 receptor blockers suramin and PPADS, suggesting activation of P2Y receptors. Bath-applied ATP induced an intracellular rise in calcium in Müller cells; both the calcium rise and the extracellular H+ fluxes were significantly attenuated when calcium re-loading into the endoplasmic reticulum was inhibited by thapsigargin and when the PLC-IP3 signaling pathway was disrupted with 2-APB and U73122. The anion transport inhibitor DIDS also markedly reduced the ATP-induced increase in H+ flux while SITS had no effect. ATP-induced H+ fluxes were also observed from Müller cells isolated from human, rat, monkey, skate and lamprey retinae, suggesting a highly evolutionarily conserved mechanism of potential general importance. Extracellular ATP also induced significant increases in extracellular H+ flux at the level of both the outer and inner plexiform layers in retinal slices of tiger salamander which was significantly reduced by suramin and PPADS. We suggest that the novel H+ flux mediated by ATP-activation of Müller cells and of other glia as well may be a key mechanism modulating neuronal signaling in the vertebrate retina and throughout the brain.

  12. Insertion of tetracysteine motifs into dopamine transporter extracellular domains.

    Directory of Open Access Journals (Sweden)

    Deanna M Navaroli

    Full Text Available The neuronal dopamine transporter (DAT is a major determinant of extracellular dopamine (DA levels and is the primary target for a variety of addictive and therapeutic psychoactive drugs. DAT is acutely regulated by protein kinase C (PKC activation and amphetamine exposure, both of which modulate DAT surface expression by endocytic trafficking. In order to use live imaging approaches to study DAT endocytosis, methods are needed to exclusively label the DAT surface pool. The use of membrane impermeant, sulfonated biarsenic dyes holds potential as one such approach, and requires introduction of an extracellular tetracysteine motif (tetraCys; CCPGCC to facilitate dye binding. In the current study, we took advantage of intrinsic proline-glycine (Pro-Gly dipeptides encoded in predicted DAT extracellular domains to introduce tetraCys motifs into DAT extracellular loops 2, 3, and 4. [(3H]DA uptake studies, surface biotinylation and fluorescence microscopy in PC12 cells indicate that tetraCys insertion into the DAT second extracellular loop results in a functional transporter that maintains PKC-mediated downregulation. Introduction of tetraCys into extracellular loops 3 and 4 yielded DATs with severely compromised function that failed to mature and traffic to the cell surface. This is the first demonstration of successful introduction of a tetracysteine motif into a DAT extracellular domain, and may hold promise for use of biarsenic dyes in live DAT imaging studies.

  13. [Current Treatment of Stable Angina].

    Science.gov (United States)

    Toggweiler, Stefan; Jamshidi, Peiman; Cuculi, Florim

    2015-06-17

    Current therapy for stable angina includes surgical and percutaneous revascularization, which has been improved tremendously over the last decades. Smoking cessation and regular exercise are the cornerstone for prevention of further cerebrovascular events. Medical treatment includes treatment of cardiovascular risk factors and antithrombotic management, which can be a challenge in some patients. Owing to the fact the coronary revascularization is readily accessible these days in many industrialized countries, the importance of antianginal therapy has decreased over the past years. This article presents a contemporary overview of the management of patients with stable angina in the year 2015.

  14. Extracellular electron transfer mechanisms between microorganisms and minerals

    Energy Technology Data Exchange (ETDEWEB)

    Shi, Liang; Dong, Hailiang; Reguera, Gemma; Beyenal, Haluk; Lu, Anhuai; Liu, Juan; Yu, Han-Qing; Fredrickson, James K.

    2016-08-30

    Electrons can be transferred from microorganisms to multivalent metal ions that are associated with minerals and vice versa. As the microbial cell envelope is neither physically permeable to minerals nor electrically conductive, microorganisms have evolved strategies to exchange electrons with extracellular minerals. In this Review, we discuss the molecular mechanisms that underlie the ability of microorganisms to exchange electrons, such as c-type cytochromes and microbial nanowires, with extracellular minerals and with microorganisms of the same or different species. Microorganisms that have extracellular electron transfer capability can be used for biotechnological applications, including bioremediation, biomining and the production of biofuels and nanomaterials.

  15. Surface glycosylation profiles of urine extracellular vesicles.

    Directory of Open Access Journals (Sweden)

    Jared Q Gerlach

    Full Text Available Urinary extracellular vesicles (uEVs are released by cells throughout the nephron and contain biomolecules from their cells of origin. Although uEV-associated proteins and RNA have been studied in detail, little information exists regarding uEV glycosylation characteristics. Surface glycosylation profiling by flow cytometry and lectin microarray was applied to uEVs enriched from urine of healthy adults by ultracentrifugation and centrifugal filtration. The carbohydrate specificity of lectin microarray profiles was confirmed by competitive sugar inhibition and carbohydrate-specific enzyme hydrolysis. Glycosylation profiles of uEVs and purified Tamm Horsfall protein were compared. In both flow cytometry and lectin microarray assays, uEVs demonstrated surface binding, at low to moderate intensities, of a broad range of lectins whether prepared by ultracentrifugation or centrifugal filtration. In general, ultracentrifugation-prepared uEVs demonstrated higher lectin binding intensities than centrifugal filtration-prepared uEVs consistent with lesser amounts of co-purified non-vesicular proteins. The surface glycosylation profiles of uEVs showed little inter-individual variation and were distinct from those of Tamm Horsfall protein, which bound a limited number of lectins. In a pilot study, lectin microarray was used to compare uEVs from individuals with autosomal dominant polycystic kidney disease to those of age-matched controls. The lectin microarray profiles of polycystic kidney disease and healthy uEVs showed differences in binding intensity of 6/43 lectins. Our results reveal a complex surface glycosylation profile of uEVs that is accessible to lectin-based analysis following multiple uEV enrichment techniques, is distinct from co-purified Tamm Horsfall protein and may demonstrate disease-specific modifications.

  16. Modular Extracellular Matrices: Solutions for the Puzzle

    Science.gov (United States)

    Serban, Monica A.; Prestwich, Glenn D.

    2008-01-01

    The common technique of growing cells in two-dimensions (2-D) is gradually being replaced by culturing cells on matrices with more appropriate composition and stiffness, or by encapsulation of cells in three-dimensions (3-D). The universal acceptance of the new 3-D paradigm has been constrained by the absence of a commercially available, biocompatible material that offers ease of use, experimental flexibility, and a seamless transition from in vitro to in vivo applications. The challenge – the puzzle that needs a solution – is to replicate the complexity of the native extracellular matrix (ECM) environment with the minimum number of components necessary to allow cells to rebuild and replicate a given tissue. For use in drug discovery, toxicology, cell banking, and ultimately in reparative medicine, the ideal matrix would therefore need to be highly reproducible, manufacturable, approvable, and affordable. Herein we describe the development of a set of modular components that can be assembled into biomimetic materials that meet these requirements. These semi-synthetic ECMs, or sECMs, are based on hyaluronan derivatives that form covalently crosslinked, biodegradable hydrogels suitable for 3-D culture of primary and stem cells in vitro, and for tissue formation in vivo. The sECMs can be engineered to provide appropriate biological cues needed to recapitulate the complexity of a given ECM environment. Specific applications for different sECM compositions include stem cell expansion with control of differentiation, scar-free wound healing, growth factor delivery, cell delivery for osteochondral defect and liver repair, and development of vascularized tumor xenografts for personalized chemotherapy. PMID:18442709

  17. Neutrophil extracellular trap formation in supragingival biofilms.

    Science.gov (United States)

    Hirschfeld, Josefine; Dommisch, Henrik; Skora, Philipp; Horvath, Gabor; Latz, Eicke; Hoerauf, Achim; Waller, Tobias; Kawai, Toshihisa; Jepsen, Søren; Deschner, James; Bekeredjian-Ding, Isabelle

    2015-01-01

    Oral biofilms are the causative agents of the highly prevalent oral diseases periodontitis and caries. Additionally, the host immune response is thought to play a critical role in disease onset. Neutrophils are known to be a key host response factor to bacterial challenge on host surfaces. Release of neutrophil extracellular traps (NETs) as a novel antimicrobial defense strategy has gained increasing attention in the past years. Here, we investigated the influx of neutrophils into the dental plaque and the ability of oral bacteria to trigger intra-biofilm release of NETs and intracellular proteins. Supragingival biofilms and whole saliva were sampled from systemically healthy subjects participating in an experimental gingivitis study. Biofilms were analysed by immunofluorescence followed by confocal and fluorescence microscopy. Moreover, concentrations of cytokines and immune-associated proteins in biofilm suspensions and saliva were assessed by ELISA. Neutrophils obtained from blood were stimulated with twelve bacterial species isolated from cultured biofilms or with lipopolysaccharide to monitor NET formation. Neutrophils, NETs, neutrophil-associated proteins (myeloperoxidase, elastase-2, cathepsin G, cathelicidin LL-37), interleukin-8, interleukin-1β and tumor necrosis factor were detected within plaque samples and saliva. All tested bacterial species as well as the polymicrobial samples isolated from the plaque of each donor induced release of NETs and interleukin-8. The degree of NET formation varied among different subjects and did not correlate with plaque scores or clinical signs of local inflammation. Our findings indicate that neutrophils are attracted towards dental biofilms, in which they become incorporated and where they are stimulated by microbes to release NETs and immunostimulatory proteins. Thus, neutrophils and NETs may be involved in host biofilm control, although their specific role needs to be further elucidated. Moreover, inter

  18. Possibility of stable quark stars

    International Nuclear Information System (INIS)

    Bowers, R.L.; Gleeson, A.M.; Pedigo, R.D.

    1976-08-01

    A recent zero temperature equation of state which contains quark-partons separated from conventional baryons by a phase transition is used to investigate the stability of quark stars. The sensitivity to the input physics is also considered. The conclusions, which are found to be relatively model independent, indicate that a separately identifiable class of stable objects called quark stars does not exist

  19. Radiation-stable polyolefin compositions

    International Nuclear Information System (INIS)

    Rekers, J.W.

    1986-01-01

    This invention relates to compositions of olefinic polymers suitable for high energy radiation treatment. In particular, the invention relates to olefinic polymer compositions that are stable to sterilizing dosages of high energy radiation such as a gamma radiation. Stabilizers are described that include benzhydrol and benzhydrol derivatives; these stabilizers may be used alone or in combination with secondary antioxidants or synergists

  20. Incorporation of Tenascin-C into the Extracellular Matrix by Periostin Underlies an Extracellular Meshwork Architecture*

    Science.gov (United States)

    Kii, Isao; Nishiyama, Takashi; Li, Minqi; Matsumoto, Ken-ichi; Saito, Mitsuru; Amizuka, Norio; Kudo, Akira

    2010-01-01

    Extracellular matrix (ECM) underlies a complicated multicellular architecture that is subjected to significant forces from mechanical environment. Although various components of the ECM have been enumerated, mechanisms that evolve the sophisticated ECM architecture remain to be addressed. Here we show that periostin, a matricellular protein, promotes incorporation of tenascin-C into the ECM and organizes a meshwork architecture of the ECM. We found that both periostin null mice and tenascin-C null mice exhibited a similar phenotype, confined tibial periostitis, which possibly corresponds to medial tibial stress syndrome in human sports injuries. Periostin possessed adjacent domains that bind to tenascin-C and the other ECM protein: fibronectin and type I collagen, respectively. These adjacent domains functioned as a bridge between tenascin-C and the ECM, which increased deposition of tenascin-C on the ECM. The deposition of hexabrachions of tenascin-C may stabilize bifurcations of the ECM fibrils, which is integrated into the extracellular meshwork architecture. This study suggests a role for periostin in adaptation of the ECM architecture in the mechanical environment. PMID:19887451

  1. Incorporation of tenascin-C into the extracellular matrix by periostin underlies an extracellular meshwork architecture.

    Science.gov (United States)

    Kii, Isao; Nishiyama, Takashi; Li, Minqi; Matsumoto, Ken-Ichi; Saito, Mitsuru; Amizuka, Norio; Kudo, Akira

    2010-01-15

    Extracellular matrix (ECM) underlies a complicated multicellular architecture that is subjected to significant forces from mechanical environment. Although various components of the ECM have been enumerated, mechanisms that evolve the sophisticated ECM architecture remain to be addressed. Here we show that periostin, a matricellular protein, promotes incorporation of tenascin-C into the ECM and organizes a meshwork architecture of the ECM. We found that both periostin null mice and tenascin-C null mice exhibited a similar phenotype, confined tibial periostitis, which possibly corresponds to medial tibial stress syndrome in human sports injuries. Periostin possessed adjacent domains that bind to tenascin-C and the other ECM protein: fibronectin and type I collagen, respectively. These adjacent domains functioned as a bridge between tenascin-C and the ECM, which increased deposition of tenascin-C on the ECM. The deposition of hexabrachions of tenascin-C may stabilize bifurcations of the ECM fibrils, which is integrated into the extracellular meshwork architecture. This study suggests a role for periostin in adaptation of the ECM architecture in the mechanical environment.

  2. Neutrophil Extracellular Trap-Related Extracellular Histones Cause Vascular Necrosis in Severe GN.

    Science.gov (United States)

    Kumar, Santhosh V R; Kulkarni, Onkar P; Mulay, Shrikant R; Darisipudi, Murthy N; Romoli, Simone; Thomasova, Dana; Scherbaum, Christina R; Hohenstein, Bernd; Hugo, Christian; Müller, Susanna; Liapis, Helen; Anders, Hans-Joachim

    2015-10-01

    Severe GN involves local neutrophil extracellular trap (NET) formation. We hypothesized a local cytotoxic effect of NET-related histone release in necrotizing GN. In vitro, histones from calf thymus or histones released by neutrophils undergoing NETosis killed glomerular endothelial cells, podocytes, and parietal epithelial cells in a dose-dependent manner. Histone-neutralizing agents such as antihistone IgG, activated protein C, or heparin prevented this effect. Histone toxicity on glomeruli ex vivo was Toll-like receptor 2/4 dependent, and lack of TLR2/4 attenuated histone-induced renal thrombotic microangiopathy and glomerular necrosis in mice. Anti-glomerular basement membrane GN involved NET formation and vascular necrosis, whereas blocking NET formation by peptidylarginine inhibition or preemptive anti-histone IgG injection significantly reduced all aspects of GN (i.e., vascular necrosis, podocyte loss, albuminuria, cytokine induction, recruitment or activation of glomerular leukocytes, and glomerular crescent formation). To evaluate histones as a therapeutic target, mice with established GN were treated with three different histone-neutralizing agents. Anti-histone IgG, recombinant activated protein C, and heparin were equally effective in abrogating severe GN, whereas combination therapy had no additive effects. Together, these results indicate that NET-related histone release during GN elicits cytotoxic and immunostimulatory effects. Furthermore, neutralizing extracellular histones is still therapeutic when initiated in established GN. Copyright © 2015 by the American Society of Nephrology.

  3. Cosmetic applications of glucitol-core containing gallotannins from a proprietary phenolic-enriched red maple (Acer rubrum) leaves extract: inhibition of melanogenesis via down-regulation of tyrosinase and melanogenic gene expression in B16F10 melanoma cells.

    Science.gov (United States)

    Ma, Hang; Xu, Jialin; DaSilva, Nicholas A; Wang, Ling; Wei, Zhengxi; Guo, Liangran; Johnson, Shelby L; Lu, Wei; Xu, Jun; Gu, Qiong; Seeram, Navindra P

    2017-05-01

    The red maple (Acer rubrum) is a rich source of phenolic compounds which possess galloyl groups attached to different positions of a 1,5-anhydro-D-glucitol core. While these glucitol-core containing gallotannins (GCGs) have reported anti-oxidant and anti-glycative effects, they have not yet been evaluated for their cosmetic applications. Herein, the anti-tyrosinase and anti-melanogenic effects of a proprietary phenolic-enriched red maple leaves extract [Maplifa ™ ; contains ca. 45% ginnalin A (GA) along with other GCGs] were investigated using enzyme and cellular assays. The GCGs showed anti-tyrosinase activity with IC 50 values ranging from 101.4 to 1047.3 μM and their mechanism of tyrosinase inhibition (using GA as a representative GCG) was evaluated by chelating and computational/modeling studies. GA reduced melanin content in murine melanoma B16F10 cells by 79.1 and 56.7% (at non-toxic concentrations of 25 and 50 μM, respectively), and its mechanisms of anti-melanogenic effects were evaluated by using methods including fluorescent probe (DCF-DA), real-time PCR, and western blot experiments. These data indicated that GA was able to: (1) reduce the levels of reactive oxygen species, (2) down-regulate the expression of MITF, TYR, TRP-1, and TRP-2 gene levels in a time-dependent manner, and (3) significantly reduce protein expression of the TRP-2 gene. Therefore, the anti-melanogenic effects of red maple GCGs warrant further investigation of this proprietary natural product extract for potential cosmetic applications.

  4. Improved Methods of Producing and Administering Extracellular Vesicles | Poster

    Science.gov (United States)

    An efficient method of producing purified extracellular vesicles (EVs), in conjunction with a method that blocks liver macrophages from clearing EVs from the body, has produced promising results for the use of EVs in cancer therapy.

  5. EVpedia : a community web portal for extracellular vesicles research

    NARCIS (Netherlands)

    Kim, Dae-Kyum; Lee, Jaewook; Kim, Sae Rom; Choi, Dong-Sic; Yoon, Yae Jin; Kim, Ji Hyun; Go, Gyeongyun; Nhung, Dinh; Hong, Kahye; Jang, Su Chul; Kim, Si-Hyun; Park, Kyong-Su; Kim, Oh Youn; Park, Hyun Taek; Seo, Ji Hye; Aikawa, Elena; Baj-Krzyworzeka, Monika; van Balkom, Bas W M; Belting, Mattias; Blanc, Lionel; Bond, Vincent; Bongiovanni, Antonella; Borràs, Francesc E; Buée, Luc; Buzás, Edit I; Cheng, Lesley; Clayton, Aled; Cocucci, Emanuele; Dela Cruz, Charles S; Desiderio, Dominic M; Di Vizio, Dolores; Ekström, Karin; Falcon-Perez, Juan M; Gardiner, Chris; Giebel, Bernd; Greening, David W; Gross, Julia Christina; Gupta, Dwijendra; Hendrix, An; Hill, Andrew F; Hill, Michelle M; Nolte-'t Hoen, Esther; Hwang, Do Won; Inal, Jameel; Jagannadham, Medicharla V; Jayachandran, Muthuvel; Jee, Young-Koo; Jørgensen, Malene; Kim, Kwang Pyo; Kim, Yoon-Keun; Kislinger, Thomas; Lässer, Cecilia; Lee, Dong Soo; Lee, Hakmo; van Leeuwen, Johannes; Lener, Thomas; Liu, Ming-Lin; Lötvall, Jan; Marcilla, Antonio; Mathivanan, Suresh; Möller, Andreas; Morhayim, Jess; Mullier, François; Nazarenko, Irina; Nieuwland, Rienk; Nunes, Diana N; Pang, Ken; Park, Jaesung; Patel, Tushar; Pocsfalvi, Gabriella; Del Portillo, Hernando; Putz, Ulrich; Ramirez, Marcel I; Rodrigues, Marcio L; Roh, Tae-Young; Royo, Felix; Sahoo, Susmita; Schiffelers, Raymond|info:eu-repo/dai/nl/212909509; Sharma, Shivani; Siljander, Pia; Simpson, Richard J; Soekmadji, Carolina; Stahl, Philip; Stensballe, Allan; Stępień, Ewa; Tahara, Hidetoshi; Trummer, Arne; Valadi, Hadi; Vella, Laura J; Wai, Sun Nyunt; Witwer, Kenneth; Yáñez-Mó, María; Youn, Hyewon; Zeidler, Reinhard; Gho, Yong Song; Nolte - t Hoen, Esther|info:eu-repo/dai/nl/261632175

    2014-01-01

    MOTIVATION: Extracellular vesicles (EVs) are spherical bilayered proteolipids, harboring various bioactive molecules. Due to the complexity of the vesicular nomenclatures and components, online searches for EV-related publications and vesicular components are currently challenging. RESULTS: We

  6. EVpedia: a community web portal for extracellular vesicles research

    NARCIS (Netherlands)

    Kim, Dae-Kyum; Lee, Jaewook; Kim, Sae Rom; Choi, Dong-Sic; Yoon, Yae Jin; Kim, Ji Hyun; Go, Gyeongyun; Nhung, Dinh; Hong, Kahye; Jang, Su Chul; Kim, Si-Hyun; Park, Kyong-Su; Kim, Oh Youn; Park, Hyun Taek; Seo, Ji Hye; Aikawa, Elena; Baj-Krzyworzeka, Monika; van Balkom, Bas W. M.; Belting, Mattias; Blanc, Lionel; Bond, Vincent; Bongiovanni, Antonella; Borràs, Francesc E.; Buée, Luc; Buzás, Edit I.; Cheng, Lesley; Clayton, Aled; Cocucci, Emanuele; Dela Cruz, Charles S.; Desiderio, Dominic M.; Di Vizio, Dolores; Ekström, Karin; Falcon-Perez, Juan M.; Gardiner, Chris; Giebel, Bernd; Greening, David W.; Gross, Julia Christina; Gupta, Dwijendra; Hendrix, An; Hill, Andrew F.; Hill, Michelle M.; Nolte-'t Hoen, Esther; Hwang, Do Won; Inal, Jameel; Jagannadham, Medicharla V.; Jayachandran, Muthuvel; Jee, Young-Koo; Jørgensen, Malene; Kim, Kwang Pyo; Kim, Yoon-Keun; Kislinger, Thomas; Lässer, Cecilia; Lee, Dong Soo; Lee, Hakmo; van Leeuwen, Johannes; Lener, Thomas; Liu, Ming-Lin; Lötvall, Jan; Marcilla, Antonio; Mathivanan, Suresh; Möller, Andreas; Morhayim, Jess; Mullier, François; Nazarenko, Irina; Nieuwland, Rienk; Nunes, Diana N.; Pang, Ken; Park, Jaesung; Patel, Tushar; Pocsfalvi, Gabriella; del Portillo, Hernando; Putz, Ulrich; Ramirez, Marcel I.; Rodrigues, Marcio L.; Roh, Tae-Young; Royo, Felix; Sahoo, Susmita; Schiffelers, Raymond; Sharma, Shivani; Siljander, Pia; Simpson, Richard J.; Soekmadji, Carolina; Stahl, Philip; Stensballe, Allan; Stępień, Ewa; Tahara, Hidetoshi; Trummer, Arne; Valadi, Hadi; Vella, Laura J.; Wai, Sun Nyunt; Witwer, Kenneth; Yáñez-Mó, María; Youn, Hyewon; Zeidler, Reinhard; Gho, Yong Song

    2015-01-01

    Extracellular vesicles (EVs) are spherical bilayered proteolipids, harboring various bioactive molecules. Due to the complexity of the vesicular nomenclatures and components, online searches for EV-related publications and vesicular components are currently challenging. We present an improved

  7. Biological properties of extracellular vesicles and their physiological functions

    NARCIS (Netherlands)

    Yáñez-Mó, María; Siljander, Pia R-M; Andreu, Zoraida; Zavec, Apolonija Bedina; Borràs, Francesc E; Buzas, Edit I; Buzas, Krisztina; Casal, Enriqueta; Cappello, Francesco; Carvalho, Joana; Colás, Eva; Cordeiro-da Silva, Anabela; Fais, Stefano; Falcon-Perez, Juan M; Ghobrial, Irene M; Giebel, Bernd; Gimona, Mario; Graner, Michael; Gursel, Ihsan; Gursel, Mayda; Heegaard, Niels H H; Hendrix, An; Kierulf, Peter; Kokubun, Katsutoshi; Kosanovic, Maja; Kralj-Iglic, Veronika; Krämer-Albers, Eva-Maria; Laitinen, Saara; Lässer, Cecilia; Lener, Thomas; Ligeti, Erzsébet; Linē, Aija; Lipps, Georg; Llorente, Alicia; Lötvall, Jan; Manček-Keber, Mateja; Marcilla, Antonio; Mittelbrunn, Maria; Nazarenko, Irina; Nolte-'t Hoen, Esther N M; Nyman, Tuula A; O'Driscoll, Lorraine; Olivan, Mireia; Oliveira, Carla; Pállinger, Éva; Del Portillo, Hernando A; Reventós, Jaume; Rigau, Marina; Rohde, Eva; Sammar, Marei; Sánchez-Madrid, Francisco; Santarém, N; Schallmoser, Katharina; Ostenfeld, Marie Stampe; Stoorvogel, Willem|info:eu-repo/dai/nl/074352385; Stukelj, Roman; Van der Grein, Susanne G|info:eu-repo/dai/nl/412755211; Vasconcelos, M Helena; Wauben, Marca H M|info:eu-repo/dai/nl/112675735; De Wever, Olivier

    2015-01-01

    In the past decade, extracellular vesicles (EVs) have been recognized as potent vehicles of intercellular communication, both in prokaryotes and eukaryotes. This is due to their capacity to transfer proteins, lipids and nucleic acids, thereby influencing various physiological and pathological

  8. Electrochemical roles of extracellular polymeric substances in biofilms

    DEFF Research Database (Denmark)

    Xiao, Yong; Zhao, Feng

    2017-01-01

    Most microbial cells in nature are surrounded by extracellular polymeric substances (EPS), which are fundamental components and determine the physiochemical properties of a biofilm. This review highlights the EPS properties of conductivity and redox ability from an electrochemical perspective, em...

  9. Extracellular matrix scaffolds for cartilage and bone regeneration

    NARCIS (Netherlands)

    Benders, K.E.M.; van Weeren, P.R.; Badylak, S.F.; Saris, Daniël B.F.; Dhert, W.J.A.; Malda, J.

    2013-01-01

    Regenerative medicine approaches based on decellularized extracellular matrix (ECM) scaffolds and tissues are rapidly expanding. The rationale for using ECM as a natural biomaterial is the presence of bioactive molecules that drive tissue homeostasis and regeneration. Moreover, appropriately

  10. Extracellular vesicles provide a means for tissue crosstalk during exercise

    DEFF Research Database (Denmark)

    Whitham, Martin; Parker, Benjamin L; Friedrichsen, Martin

    2018-01-01

    Exercise stimulates the release of molecules into the circulation, supporting the concept that inter-tissue signaling proteins are important mediators of adaptations to exercise. Recognizing that many circulating proteins are packaged in extracellular vesicles (EVs), we employed quantitative prot...

  11. EVpedia : A community web portal for extracellular vesicles research

    NARCIS (Netherlands)

    Kim, Dae Kyum; Lee, Jaewook; Kim, Sae Rom; Choi, Dong Sic; Yoon, Yae Jin; Kim, Ji Hyun; Go, Gyeongyun; Nhung, Dinh; Hong, Kahye; Jang, Su Chul; Kim, Si Hyun; Park, Kyong Su; Kim, Oh Youn; Park, Hyun Taek; Seo, Ji Hye; Aikawa, Elena; Baj-Krzyworzeka, Monika; Van Balkom, Bas W M; Belting, Mattias; Blanc, Lionel; Bond, Vincent; Bongiovanni, Antonella; Borràs, Francesc E.; Buée, Luc; Buzás, Edit I.; Cheng, Lesley; Clayton, Aled; Cocucci, Emanuele; Dela Cruz, Charles S.; Desiderio, Dominic M.; Di Vizio, Dolores; Ekström, Karin; Falcon-Perez, Juan M.; Gardiner, Chris; Giebel, Bernd; Greening, David W.; Christina Gross, Julia; Gupta, Dwijendra; Hendrix, An; Hill, Andrew F.; Hill, Michelle M.; Nolte-'T Hoen, Esther; Hwang, Do Won; Inal, Jameel; Jagannadham, Medicharla V.; Jayachandran, Muthuvel; Jee, Young Koo; Jørgensen, Malene; Kim, Kwang Pyo; Kim, Yoon Keun; Kislinger, Thomas; Lässer, Cecilia; Lee, Dong Soo; Lee, Hakmo; Van Leeuwen, Johannes; Lener, Thomas; Liu, Ming Lin; Lötvall, Jan; Marcilla, Antonio; Mathivanan, Suresh; Möller, Andreas; Morhayim, Jess; Mullier, Francois; Nazarenko, Irina; Nieuwland, Rienk; Nunes, Diana N.; Pang, Ken; Park, Jaesung; Patel, Tushar; Pocsfalvi, Gabriella; Del Portillo, Hernando; Putz, Ulrich; Ramirez, Marcel I.; Rodrigues, Marcio L.; Roh, Tae Young; Royo, Felix; Sahoo, Susmita; Schiffelers, Raymond; Sharma, Shivani; Siljander, Pia; Simpson, Richard J.; Soekmadji, Carolina; Stahl, Philip; Stensballe, Allan; Stepień, Ewa; Tahara, Hidetoshi; Trummer, Arne; Valadi, Hadi; Vella, Laura J.; Wai, Sun Nyunt; Witwer, Kenneth; Yánez-Mó, Maria; Youn, Hyewon; Zeidler, Reinhard; Gho, Yong Song

    2015-01-01

    Motivation: Extracellular vesicles (EVs) are spherical bilayered proteolipids, harboring various bioactive molecules. Due to the complexity of the vesicular nomenclatures and components, online searches for EV-related publications and vesicular components are currently challenging. Results: We

  12. The role of extracellular histones in haematological disorders.

    Science.gov (United States)

    Alhamdi, Yasir; Toh, Cheng-Hock

    2016-06-01

    Over the past decades, chromosomal alterations have been extensively investigated for their pathophysiological relevance in haematological malignancies. In particular, epigenetic modifications of intra-nuclear histones are now known as key regulators of healthy cell cycles that have also evolved into novel therapeutic targets for certain blood cancers. Thus, for most haematologists, histones are DNA-chained proteins that are buried deep within chromatin. However, the plot has deepened with recent revelations on the function of histones when unchained and released extracellularly upon cell death or from activated neutrophils as part of neutrophil extracellular traps (NETs). Extracellular histones and NETs are increasingly recognized for profound cytotoxicity and pro-coagulant effects. This article highlights the importance of recognizing this new paradigm of extracellular histones as a key player in host defence through its damage-associated molecular patterns, which could translate into novel diagnostic and therapeutic biomarkers in various haematological and critical disorders. © 2016 John Wiley & Sons Ltd.

  13. In vivo extracellular matrix protein expression by human periodontal ...

    African Journals Online (AJOL)

    ONOS

    2010-08-23

    Aug 23, 2010 ... Extracellular matrix proteins (ECM) are described as molecular regulators of these events. ..... zation and adhesive interaction of cells (Yamada, 1983). .... periodontal ligament fibroblasts after simulation of orthodontic force.

  14. Dopamine transporters govern diurnal variation in extracellular dopamine tone

    OpenAIRE

    Ferris, Mark J.; España, Rodrigo A.; Locke, Jason L.; Konstantopoulos, Joanne K.; Rose, Jamie H.; Chen, Rong; Jones, Sara R.

    2014-01-01

    The mechanism for diurnal (i.e., light/dark) oscillations in extracellular dopamine tone in mesolimbic and nigrostriatal systems is unknown. This is because, unlike other neurotransmitter systems, variation in dopamine tone does not correlate with variation in dopamine cell firing. The current research pinpoints the dopamine transporter as a critical governor of diurnal variation in both extracellular dopamine tone and the intracellular availability of releasable dopamine. These data describe...

  15. The extracellular matrix of plants: Molecular, cellular and developmental biology

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-12-31

    A symposium entitled ``The Extracellular Matrix of Plants: Molecular, Cellular and Developmental Biology was held in Tamarron, Colorado, March 15--21, 1996. The following topics were explored in addresses by 43 speakers: structure and biochemistry of cell walls; biochemistry, molecular biology and biosynthesis of lignin; secretory pathway and synthesis of glycoproteins; biosynthesis of matrix polysaccharides, callose and cellulose; role of the extracellular matrix in plant growth and development; plant cell walls in symbiosis and pathogenesis.

  16. Effects of ionizing radiation on extracellular matrix

    Energy Technology Data Exchange (ETDEWEB)

    Mohamed, F. [School of Physics, University of Exeter, Exeter EX44QL (United Kingdom)], E-mail: f.mohamed@ex.ac.uk; Bradley, D.A. [Department of Physics, University of Surrey, Guildford GU72XH (United Kingdom); Winlove, C.P. [School of Physics, University of Exeter, Exeter EX44QL (United Kingdom)

    2007-09-21

    The extracellular matrix is a ubiquitous and important component of tissues. We investigated the effects of ionizing radiation on the physical properties of its principal macromolecular components, pericardial collagen, ligament elastin and hyaluronan, a representative glycosaminoglycan. Samples were exposed to X-rays from an electron linear accelerator in the range of 10-100 Gy to cover the range of irradiation exposure during radiotherapy. A uniaxial mechanical testing protocol was used to characterize the fibrous proteins. For pericardial tissue the major change was an increase in the elastic modulus in the toe region of the curve ({<=}20% strain), from 23{+-}18 kPa for controls to 57{+-}22 kPa at a dose of 10 Gy (p=0.01, {alpha}=0.05). At larger strain ({>=}20% strain), the elastic modulus in the linear region decreased from 1.92{+-}0.70 MPa for control pericardium tissue to 1.31{+-}0.56 MPa (p=0.01, {alpha}=0.05) for 10 Gy X-irradiated sample. Similar observations have been made previously on tendon collagen at larger strains. For elastin, the stress-strain relationship was linear up to 30% strain, but the elastic modulus decreased significantly with irradiation (controls 626{+-}65 kPa, irradiated 474{+-}121 kPa (p=0.02, {alpha}=0.05), at 10 Gy X-irradiation). The results suggest that for collagen the primary effect of irradiation is generation of additional cross-links, while for elastin chain scissions are important. The viscosity of HA (at 1.25% w/v and 0.125% w/v) was measured by both cone and plate and capillary viscometry, the former providing measurement at uniform shear rate and the latter providing a more sensitive indication of changes at low viscosity. Both techniques revealed a dose-dependent reduction in viscosity (from 3400{+-}194 cP for controls to 1500{+-}88 cP at a shear rate of 2 s{sup -1} and dose of 75 Gy), again suggesting depolymerization.

  17. Effects of ionizing radiation on extracellular matrix

    International Nuclear Information System (INIS)

    Mohamed, F.; Bradley, D.A.; Winlove, C.P.

    2007-01-01

    The extracellular matrix is a ubiquitous and important component of tissues. We investigated the effects of ionizing radiation on the physical properties of its principal macromolecular components, pericardial collagen, ligament elastin and hyaluronan, a representative glycosaminoglycan. Samples were exposed to X-rays from an electron linear accelerator in the range of 10-100 Gy to cover the range of irradiation exposure during radiotherapy. A uniaxial mechanical testing protocol was used to characterize the fibrous proteins. For pericardial tissue the major change was an increase in the elastic modulus in the toe region of the curve (≤20% strain), from 23±18 kPa for controls to 57±22 kPa at a dose of 10 Gy (p=0.01, α=0.05). At larger strain (≥20% strain), the elastic modulus in the linear region decreased from 1.92±0.70 MPa for control pericardium tissue to 1.31±0.56 MPa (p=0.01, α=0.05) for 10 Gy X-irradiated sample. Similar observations have been made previously on tendon collagen at larger strains. For elastin, the stress-strain relationship was linear up to 30% strain, but the elastic modulus decreased significantly with irradiation (controls 626±65 kPa, irradiated 474±121 kPa (p=0.02, α=0.05), at 10 Gy X-irradiation). The results suggest that for collagen the primary effect of irradiation is generation of additional cross-links, while for elastin chain scissions are important. The viscosity of HA (at 1.25% w/v and 0.125% w/v) was measured by both cone and plate and capillary viscometry, the former providing measurement at uniform shear rate and the latter providing a more sensitive indication of changes at low viscosity. Both techniques revealed a dose-dependent reduction in viscosity (from 3400±194 cP for controls to 1500±88 cP at a shear rate of 2 s -1 and dose of 75 Gy), again suggesting depolymerization

  18. The Role of Extracellular Histones in Influenza Virus Pathogenesis.

    Science.gov (United States)

    Ashar, Harshini K; Mueller, Nathan C; Rudd, Jennifer M; Snider, Timothy A; Achanta, Mallika; Prasanthi, Maram; Pulavendran, Sivasami; Thomas, Paul G; Ramachandran, Akhilesh; Malayer, Jerry R; Ritchey, Jerry W; Rajasekhar, Rachakatla; Chow, Vincent T K; Esmon, Charles T; Teluguakula, Narasaraju

    2018-01-01

    Although exaggerated host immune responses have been implicated in influenza-induced lung pathogenesis, the etiologic factors that contribute to these events are not completely understood. We previously demonstrated that neutrophil extracellular traps exacerbate pulmonary injury during influenza pneumonia. Histones are the major protein components of neutrophil extracellular traps and are known to have cytotoxic effects. Here, we examined the role of extracellular histones in lung pathogenesis during influenza. Mice infected with influenza virus displayed high accumulation of extracellular histones, with widespread pulmonary microvascular thrombosis. Occluded pulmonary blood vessels with vascular thrombi often exhibited endothelial necrosis surrounded by hemorrhagic effusions and pulmonary edema. Histones released during influenza induced cytotoxicity and showed strong binding to platelets within thrombi in infected mouse lungs. Nasal wash samples from influenza-infected patients also showed increased accumulation of extracellular histones, suggesting a possible clinical relevance of elevated histones in pulmonary injury. Although histones inhibited influenza growth in vitro, in vivo treatment with histones did not yield antiviral effects and instead exacerbated lung pathology. Blocking with antihistone antibodies caused a marked decrease in lung pathology in lethal influenza-challenged mice and improved protection when administered in combination with the antiviral agent oseltamivir. These findings support the pathogenic effects of extracellular histones in that pulmonary injury during influenza was exacerbated. Targeting histones provides a novel therapeutic approach to influenza pneumonia. Copyright © 2018 American Society for Investigative Pathology. Published by Elsevier Inc. All rights reserved.

  19. The albinism of the feral Asinara white donkeys (Equus asinus) is determined by a missense mutation in a highly conserved position of the tyrosinase (TYR) gene deduced protein.

    Science.gov (United States)

    Utzeri, V J; Bertolini, F; Ribani, A; Schiavo, G; Dall'Olio, S; Fontanesi, L

    2016-02-01

    A feral donkey population (Equus asinus), living in the Asinara National Park (an island north-west of Sardinia, Italy), includes a unique white albino donkey subpopulation or colour morph that is a major attraction of this park. Disrupting mutations in the tyrosinase (TYR) gene are known to cause recessive albinisms in humans (oculocutaneous albinism Type 1; OCA1) and other species. In this study, we analysed the donkey TYR gene as a strong candidate to identify the causative mutation of the albinism of these donkeys. The TYR gene was sequenced from 13 donkeys (seven Asinara white albino and six coloured animals). Seven single nucleotide polymorphisms were identified. A missense mutation (c.604C>G; p.His202Asp) in a highly conserved amino acid position (even across kingdoms), which disrupts the first copper-binding site (CuA) of functional protein, was identified in the homozygous condition (G/G or D/D) in all Asinara white albino donkeys and in the albino son of a trio (the grey parents had genotype C/G or H/D), supporting the recessive mode of inheritance of this mutation. Genotyping 82 donkeys confirmed that Asinara albino donkeys had genotype G/G whereas all other coloured donkeys had genotype C/C or C/G. Across-population association between the c.604C>G genotypes and the albino coat colour was highly significant (P = 6.17E-18). The identification of the causative mutation of the albinism in the Asinara white donkeys might open new perspectives to study the dynamics of this putative deleterious allele in a feral population and to manage this interesting animal genetic resource. © 2015 Stichting International Foundation for Animal Genetics.

  20. Toward Practical Secure Stable Matching

    Directory of Open Access Journals (Sweden)

    Riazi M. Sadegh

    2017-01-01

    Full Text Available The Stable Matching (SM algorithm has been deployed in many real-world scenarios including the National Residency Matching Program (NRMP and financial applications such as matching of suppliers and consumers in capital markets. Since these applications typically involve highly sensitive information such as the underlying preference lists, their current implementations rely on trusted third parties. This paper introduces the first provably secure and scalable implementation of SM based on Yao’s garbled circuit protocol and Oblivious RAM (ORAM. Our scheme can securely compute a stable match for 8k pairs four orders of magnitude faster than the previously best known method. We achieve this by introducing a compact and efficient sub-linear size circuit. We even further decrease the computation cost by three orders of magnitude by proposing a novel technique to avoid unnecessary iterations in the SM algorithm. We evaluate our implementation for several problem sizes and plan to publish it as open-source.

  1. Stable isotope research pool inventory

    International Nuclear Information System (INIS)

    1986-08-01

    This report contains a listing of electromagnetically separated stable isotopes which are available at the Oak Ridge National Laboratory for distribution for nondestructive research use on a loan basis. This inventory includes all samples of stable isotopes in the Research Materials Collection and does not designate whether a sample is out on loan or is in reprocessing. For some of the high-abundance, naturally occurring isotopes, larger amounts can be made available; for example, Ca-40 and Fe-56. All requests for the loan of samples should be submitted with a summary of the purpose of the loan to: Iotope Distribution Office, Oak Ridge National Laboratory, P.O. Box X, Oak Ridge, Tennessee 37831. Requests from non-DOE contractors and from foreign institutions require DOE approval

  2. Stable isotopes and the environment

    International Nuclear Information System (INIS)

    Krouse, H.R.

    1990-01-01

    Whereas traditionally, stable isotope research has been directed towards resource exploration and development, it is finding more frequent applications in helping to assess the impacts of resource utilization upon ecosystems. Among the many pursuits, two themes are evident: tracing the transport and conversions of pollutants in the environment and better understanding of the interplay among environmental receptors, e.g. food web studies. Stable isotope data are used primarily to identify the presence of pollutants in the environment and with a few exceptions, the consequence of their presence must be assessed by other techniques. Increasing attention has been given to the isotopic composition of humans with many potential applications in areas such as paleodiets, medicine, and criminology. In this brief overview examples are used from the Pacific Rim to illustrate the above concepts. 26 refs., 1 tab., 3 figs

  3. Effects of Recurring Droughts on Extracellular Enzyme Activity in Mountain Grassland

    Science.gov (United States)

    Fuchslueger, L.; Bahn, M.; Kienzl, S.; Hofhansl, F.; Schnecker, J.; Richter, A.

    2015-12-01

    Water availability is a key factor for biogeochemical processes and determines microbial activity and functioning, and thereby organic matter decomposition in soils by affecting the osmotic potential, soil pore connectivity, substrate diffusion and nutrient availability. Low water availability during drought periods therefore directly affects microbial activity. Recurring drought periods likely induce shifts in microbial structure that might be reflected in altered responses of microbial turnover of organic matter by extracellular enzymes. To study this we measured a set of potential extracellular enzyme activity rates (cellobiohydrolase CBH; leucine-amino-peptidase LAP; phosphatase PHOS; phenoloxidase POX), in grassland soils that were exposed to extreme experimental droughts during the growing seasons of up to five subsequent years. During the first drought period after eight weeks of rain exclusion all measured potential enzyme activities were significantly decreased. In parallel, soil extractable organic carbon and nitrogen concentrations increased and microbial community structure, determined by phospholipid fatty acid analysis, changed. In soils that were exposed to two and three drought periods only PHOS decreased. After four years of drought again CBH, PHOS and POX decreased, while LAP was unaffected; after five years of drought PHOS and POX decreased and CBH and LAP remained stable. Thus, our results suggest that recurring extreme drought events can cause different responses of extracellular enzyme activities and that the responses change over time. We will discuss whether and to what degree these changes were related to shifts in microbial community composition. However, independent of whether a solitary or a recurrent drought was imposed, in cases when enzyme activity rates were altered during drought, they quickly recovered after rewetting. Overall, our data suggest that microbial functioning in mountain grassland is sensitive to drought, but highly

  4. Towards stable acceleration in LINACS

    CERN Document Server

    Dubrovskiy, A D

    2014-01-01

    Ultra-stable and -reproducible high-energy particle beams with short bunches are needed in novel linear accelerators and, in particular, in the Compact Linear Collider CLIC. A passive beam phase stabilization system based on a bunch compression with a negative transfer matrix element R56 and acceleration at a positive off-crest phase is proposed. The motivation and expected advantages of the proposed scheme are outlined.

  5. Stable Structures for Distributed Applications

    OpenAIRE

    Eugen DUMITRASCU; Ion IVAN

    2008-01-01

    For distributed applications, we define the linear, tree and graph structure types with different variants and modalities to aggregate them. The distributed applications have assigned structures that through their characteristics influence the costs of stages for developing cycle and the costs for exploitation, transferred to each user. We also present the quality characteristics of a structure for a stable application, which is focused on stability characteristic. For that characteristic we ...

  6. Glutathione-dependent extracellular ferric reductase activities in dimorphic zoopathogenic fungi

    Science.gov (United States)

    Zarnowski, Robert; Woods, Jon P.

    2009-01-01

    In this study, extracellular glutathione-dependent ferric reductase (GSH-FeR) activities in different dimorphic zoopathogenic fungal species were characterized. Supernatants from Blastomyces dermatitidis, Histoplasma capsulatum, Paracoccidioides brasiliensis and Sporothrix schenckii strains grown in their yeast form were able to reduce iron enzymically with glutathione as a cofactor. Some variations in the level of reduction were noted amongst the strains. This activity was stable in acidic, neutral and slightly alkaline environments and was inhibited when trivalent aluminium and gallium ions were present. Using zymography, single bands of GSH-FeRs with apparent molecular masses varying from 430 to 460 kDa were identified in all strains. The same molecular mass range was determined by size exclusion chromatography. These data demonstrate that dimorphic zoopathogenic fungi produce and secrete a family of similar GSH-FeRs that may be involved in the acquisition and utilization of iron. Siderophore production by these and other fungi has sometimes been considered to provide a full explanation of iron acquisition in these organisms. Our work reveals an additional common mechanism that may be biologically and pathogenically important. Furthermore, while some characteristics of these enzymes such as extracellular location, cofactor utilization and large size are not individually unique, when considered together and shared across a range of fungi, they represent an important novel physiological feature. PMID:16000713

  7. Biosynthesis of extracellular and intracellular gold nanoparticles by Aspergillus fumigatus and A. flavus.

    Science.gov (United States)

    Gupta, Saurabh; Bector, Shruti

    2013-05-01

    Green chemistry is a boon for the development of safe, stable and ecofriendly nanostructures using biological tools. The present study was carried out to explore the potential of selected fungal strains for biosynthesis of intra- and extracellular gold nanostructures. Out of the seven cultures, two fungal strains (SBS-3 and SBS-7) were selected on the basis of development of dark pink colour in cell free supernatant and fungal beads, respectively indicative of extra- and intracellular gold nanoparticles production. Both biomass associated and cell free gold nanoparticles were characterized using X-ray diffractogram (XRD) analysis and transmission electron microscopy (TEM). XRD analysis confirmed crystalline, face-centered cubic lattice of metallic gold nanoparticles along with average crystallite size. A marginal difference in average crystallite size of extracellular (17.76 nm) and intracellular (26 and 22 nm) Au-nanostructures was observed using Scherrer equation. In TEM, a variety of shapes (triangles, spherical, hexagonal) were observed in both extra- and intracellular nanoparticles. 18S rRNA gene sequence analysis by multiple sequence alignment (BLAST) indicated 99 % homology of SBS-3 to Aspergillus fumigatus with 99 % alignment coverage and 98 % homology of SBS-7 to Aspergillus flavus with 98 % alignment coverage respectively. Native-PAGE and activity staining further confirmed enzyme linked synthesis of gold nanoparticles.

  8. Extracellular Polymeric Substances Govern the Surface Charge of Biogenic Elemental Selenium Nanoparticles

    KAUST Repository

    Jain, Rohan

    2015-02-03

    © 2014 American Chemical Society. The origin of the organic layer covering colloidal biogenic elemental selenium nanoparticles (BioSeNPs) is not known, particularly in the case when they are synthesized by complex microbial communities. This study investigated the presence of extracellular polymeric substances (EPS) on BioSeNPs. The role of EPS in capping the extracellularly available BioSeNPs was also examined. Fourier transform infrared (FT-IR) spectroscopy and colorimetric measurements confirmed the presence of functional groups characteristic of proteins and carbohydrates on the BioSeNPs, suggesting the presence of EPS. Chemical synthesis of elemental selenium nanoparticles in the presence of EPS, extracted from selenite fed anaerobic granular sludge, yielded stable colloidal spherical selenium nanoparticles. Furthermore, extracted EPS, BioSeNPs, and chemically synthesized EPS-capped selenium nanoparticles had similar surface properties, as shown by ζ-potential versus pH profiles and isoelectric point measurements. This study shows that the EPS of anaerobic granular sludge form the organic layer present on the BioSeNPs synthesized by these granules. The EPS also govern the surface charge of these BioSeNPs, thereby contributing to their colloidal properties, hence affecting their fate in the environment and the efficiency of bioremediation technologies.

  9. [Inhibitory proteins of neuritic regeneration in the extracellular matrix: structure, molecular interactions and their functions. Mechanisms of extracellular balance].

    Science.gov (United States)

    Vargas, Javier; Uribe-Escamilla, Rebeca; Alfaro-Rodríguez, Alfonso

    2013-01-01

    After injury of the central nervous system (CNS) in higher vertebrates, neurons neither grow nor reconnect with their targets because their axons or dendrites cannot regenerate within the injured site. In the CNS, the signal from the environment regulating neurite regeneration is not exclusively generated by one molecular group. This signal is generated by the interaction of various types of molecules such as extracellular matrix proteins, soluble factors and surface membrane molecules; all these elements interact with one another generating the matrix's biological state: the extracellular balance. Proteins in the balanced extracellular matrix, support and promote cellular physiological states, including neuritic regeneration. We have reviewed three types of proteins of the extracellular matrix possessing an inhibitory effect and that are determinant of neuritic regeneration failure in the CNS: chondroitin sulfate proteoglycans, keratan sulfate proteoglycans and tenascin. We also review some of the mechanisms involved in the balance of extracellular proteins such as isomerization, epimerization, sulfation and glycosylation as well as the assemblage of the extracellular matrix, the interaction between the matrix and soluble factors and its proteolytic degradation. In the final section, we have presented some examples of the matrix's role in development and in tumor propagation.

  10. Purification and properties of extracellular polysaccharide (EPS) antigens produced by different mould species.

    Science.gov (United States)

    Notermans, S; Wieten, G; Engel, H W; Rombouts, F M; Hoogerhout, P; van Boom, J H

    1987-02-01

    Extracellular polysaccharide (EPS) antigens produced by different mould species were purified and partially characterized. Purification included (NH4)2SO4 treatment, Sepharose CL-4B column chromatography and Con A-sepharose chromatography. The EPS of Penicillium digitatum, Mucor racemosus and Cladosporium cladosporioides showed high antigenic capacities. Immunologically the EPS were partially genus-specific, but cross-reactivity was observed. The EPS antigens produced by species of Penicillium, Aspergillus repens and Geotrichum candidum lost their immunological activity upon heating (100 degrees C) at pH 1.8, while the EPS antigen of M. racemosus, Rhizopus oligosporus and C. cladosporioides were stable under the same conditions. The dominant monosaccharides present in the EPS antigen were mannose, galactose and glucose. The EPS obtained from cultures of M. racemosus and R. oligosporus also contained rhamnose. In the EPS produced by Penicillium spp. and A. repens the galactose residues were determined to be immunodominant.

  11. Extracellular methionine amino peptidase (MAP production by Streptomyces gedanensis in solid-state fermentation

    Directory of Open Access Journals (Sweden)

    Raji Rahulan

    2014-04-01

    Full Text Available A bioprocess was developed for extracellular MAP production from Streptomyces gedanensis by solid-state fermentation. Response surface methodology of Box Behken Design was performed to evaluate the interaction effects of most significant variables {inoculum size, (NH42SO4 concentration, MgSO4.7H2O and tryptone on MAP production after the single parameter optimization and it resulted a maximum MAP production of 55.26 IU/g PUF after 120 h of fermentation. The concentrated crude MAP displayed a pH and temperature optimum of 8.5 and 50°C. By analyzing the thermal stability, the MAP was found to be stable in a temperature range of 50 to 55°C but lost about 50% of its activity at 65°C after 30 min. This is a first report of this kind of study for MAP.

  12. PepJ is a new extracellular proteinase of Aspergillus nidulans.

    Science.gov (United States)

    Emri, T; Szilágyi, M; László, K; M-Hamvas, M; Pócsi, I

    2009-01-01

    Under carbon starvation, Aspergillus nidulans released a metallo-proteinase with activities comparable to those of PrtA, the major extracellular serine proteinase of the fungus. The relative molar mass of the enzyme was 19 kDa as determined with both denaturing and renaturing SDS PAGE, while its isoelectric point and pH and temperature optima were 8.6, 5.5 and 65 degrees C, respectively. The enzyme was stable at pH 3.5-10.5 and was still active at 95 degrees C in the presence of azocasein substrate. MALDI-TOF MS analysis demonstrated that the proteinase was encoded by the pepJ gene (locus ID AN7962.3), and showed high similarity to deuterolysin from Aspergillus oryzae. The size of the mature enzyme, its EDTA sensitivity and heat stability also supported the view that A. nidulans PepJ is a deuterolysin-type metallo-proteinase.

  13. Skeletal muscle expresses the extracellular cyclic AMP–adenosine pathway

    Science.gov (United States)

    Chiavegatti, T; Costa, V L; Araújo, M S; Godinho, R O

    2007-01-01

    Background and purpose: cAMP is a key intracellular signalling molecule that regulates multiple processes of the vertebrate skeletal muscle. We have shown that cAMP can be actively pumped out from the skeletal muscle cell. Since in other tissues, cAMP efflux had been associated with extracellular generation of adenosine, in the present study we have assessed the fate of interstitial cAMP and the existence of an extracellular cAMP-adenosine signalling pathway in skeletal muscle. Experimental approach: cAMP efflux and/or its extracellular degradation were analysed by incubating rat cultured skeletal muscle with exogenous cAMP, forskolin or isoprenaline. cAMP and its metabolites were quantified by radioassay or HPLC, respectively. Key results: Incubation of cells with exogenous cAMP was followed by interstitial accumulation of 5′-AMP and adenosine, a phenomenon inhibited by selective inhibitors of ecto-phosphodiesterase (DPSPX) and ecto-nucleotidase (AMPCP). Activation of adenylyl cyclase (AC) in cultured cells with forskolin or isoprenaline increased cAMP efflux and extracellular generation of 5′-AMP and adenosine. Extracellular cAMP-adenosine pathway was also observed after direct and receptor-dependent stimulation of AC in rat extensor muscle ex vivo. These events were attenuated by probenecid, an inhibitor of ATP binding cassette family transporters. Conclusions and implications: Our results show the existence of an extracellular biochemical cascade that converts cAMP into adenosine. The functional relevance of this extracellular signalling system may involve a feedback modulation of cellular response initiated by several G protein-coupled receptor ligands, amplifying cAMP influence to a paracrine mode, through its metabolite, adenosine. PMID:18157164

  14. Organic synthesis with stable isotopes

    International Nuclear Information System (INIS)

    Daub, G.H.; Kerr, V.N.; Williams, D.L.; Whaley, T.W.

    1978-01-01

    Some general considerations concerning organic synthesis with stable isotopes are presented. Illustrative examples are described and discussed. The examples include DL-2-amino-3-methyl- 13 C-butanoic-3,4- 13 C 2 acid (DL-valine- 13 C 3 ); methyl oleate-1- 13 C; thymine-2,6- 13 C 2 ; 2-aminoethanesulfonic- 13 C acid (taurine- 13 C); D-glucose-6- 13 C; DL-2-amino-3-methylpentanoic-3,4- 13 C 2 acid (DL-isoleucine- 13 C 2 ); benzidine- 15 N 2 ; and 4-ethylsulfonyl-1-naphthalene-sulfonamide- 15 N

  15. Stable isotopes - separation and application

    International Nuclear Information System (INIS)

    Lockhart, I.M.

    1980-01-01

    In this review, methods used for the separation of stable isotopes ( 12 C, 13 C, 14 N, 15 N, 16 O, 17 O, 18 O, 34 S) will be described. The synthesis of labelled compounds, techniques for detection and assay, and areas of application will also be discussed. Particular attention will be paid to the isotopes of carbon, nitrogen, and oxygen; to date, sulphur isotopes have only assumed a minor role. The field of deuterium chemistry is too extensive for adequate treatment; it will therefore be essentially excluded. (author)

  16. Stable agents for imaging investigations

    International Nuclear Information System (INIS)

    Tofe, A.J.

    1976-01-01

    This invention concerns highly stable compounds useful in preparing technetium 99m based scintiscanning exploration agents. The compounds of this invention include a pertechnetate reducing agent or a solution of oxidized pertechnetate and an efficient proportion, sufficient to stabilize the compounds in the presence of oxygen and of radiolysis products, of ascorbic acid or a pharmaceutically acceptable salt or ester of this acid. The invention also concerns a perfected process for preparing a technetium based exploration agent, consisting in codissolving the ascorbic acid or a pharmaceutically acceptable salt or ester of such an acid and a pertechnetate reducing agent in a solution of oxidized pertechnetate [fr

  17. Increased postdialysis systolic blood pressure is associated with extracellular overhydration in hemodialysis outpatients.

    Science.gov (United States)

    Nongnuch, Arkom; Campbell, Neil; Stern, Edward; El-Kateb, Sally; Fuentes, Laura; Davenport, Andrew

    2015-02-01

    Recently, intradialytic hypertension was reported to be associated with increased mortality for hemodialysis patients. To determine whether volume status plays a role in dialysis-associated hypertension, we prospectively audited 531 patients that had volume assessments measured by multiple-frequency bioelectrical impedance during their midweek dialysis session. Mean pre- and postdialysis weights were 73.2 vs 71.7 kg, and systolic blood pressures (SBPs) 140.5 vs. 130.3 mm Hg, respectively. Patients were divided into groups based on a fall in SBP of 20 mm Hg or more (32%), an increased SBP of 10 mm Hg or more (18%), and a stable group (50%). There were no differences in patient demographics, dialysis prescriptions, predialysis weight, total body (TBW), and extracellular (ECW) and intracellular water (ICW). However, the change in weight was significantly less in the increased blood pressure group (1.01 kg vs. stable 1.65, and 1.7 hypotensive). The ratio of ECW to TBW was significantly higher in the increased blood pressure group, particularly post dialysis (39.1 vs. stable 38.7% and fall in blood pressure group 38.7%). ECW overhydration was significantly greater in the increased blood pressure group post dialysis (0.7 (0.17 to 1.1) vs. stable 0.39 (-0.2 to 0.95) and fall in blood pressure group 0.38 (-0.19 to 0.86) liter). We found that patients who had increased blood pressure post dialysis had greater hydration status, particularly ECW. Thus, patients who increase their blood pressure post dialysis should have review of target weight, consideration of lowering the post-dialysis weight, and may benefit from increasing dialysis session time or frequency.

  18. Extracellular Metabolites from Industrial Microalgae and Their Biotechnological Potential

    Directory of Open Access Journals (Sweden)

    Lu Liu

    2016-10-01

    Full Text Available Industrial microalgae, as a big family of promising producers of renewable biomass feedstock, have been commercially exploited for functional food, living feed and feed additives, high-value chemicals in nutraceuticals, cosmeceuticals, and chemical reagents. Recently, microalgae have also been considered as a group that might play an important role in biofuel development and environmental protection. Almost all current products of industrial microalgae are derived from their biomass; however, large amounts of spent cell-free media are available from mass cultivation that is mostly unexploited. In this contribution we discuss that these media, which may contain a remarkable diversity of bioactive substances are worthy to be recovered for further use. Obviously, the extracellular metabolites from industrial microalgae have long been neglected in the development of production methods for valuable metabolites. With the advances in the last ten years, more and more structures and properties from extracellular metabolites have been identified, and the potential utilization over wide fields is attracting attention. Some of these extracellular metabolites can be potentially used as drugs, antioxidants, growth regulators or metal chelators. The purpose of this review is to provide an overview of the known extracellular metabolites from industrial microalgae which might be of commercial interest. The attention mainly focuses on the reports of extracellular bioactive metabolites and their potential application in biotechnology.

  19. In vitro Determination of Extracellular Proteins from Xylella fastidiosa.

    Science.gov (United States)

    Mendes, Juliano S; Santiago, André S; Toledo, Marcelo A S; Horta, Maria A C; de Souza, Alessandra A; Tasic, Ljubica; de Souza, Anete P

    2016-01-01

    The phytopathogen Xylella fastidiosa causes economic losses in important agricultural crops. Xylem vessel occlusion caused by biofilm formation is the major mechanism underlying the pathogenicity of distinct strains of X. fastidiosa . Here, we provide a detailed in vitro characterization of the extracellular proteins of X. fastidiosa . Based on the results, we performed a comparison with a strain J1a12, which cannot induce citrus variegated chlorosis symptoms when inoculated into citrus plants. We then extend this approach to analyze the extracellular proteins of X. fastidiosa in media supplemented with calcium. We verified increases in extracellular proteins concomitant with the days of growth and, consequently, biofilm development (3-30 days). Outer membrane vesicles carrying toxins were identified beginning at 10 days of growth in the 9a5c strain. In addition, a decrease in extracellular proteins in media supplemented with calcium was observed in both strains. Using mass spectrometry, 71 different proteins were identified during 30 days of X. fastidiosa biofilm development, including proteases, quorum-sensing proteins, biofilm formation proteins, hypothetical proteins, phage-related proteins, chaperones, toxins, antitoxins, and extracellular vesicle membrane components.

  20. Extracellular glycosylphosphatidylinositol-anchored mannoproteins and proteases of Cryptococcus neoformans.

    Science.gov (United States)

    Eigenheer, Richard A; Jin Lee, Young; Blumwald, Eduardo; Phinney, Brett S; Gelli, Angie

    2007-06-01

    Extracellular proteins of Cryptococcus neoformans are involved in the pathogenesis of cryptococcosis, and some are immunoreactive antigens that may potentially serve as candidates for vaccine development. To further study the extracellular proteome of the human fungal pathogen Cry. neoformans, we conducted a proteomic analysis of secreted and cell wall-bound proteins with an acapsular strain of Cry. neoformans. Proteins were identified from both intact cells and cell walls. In both cases, extracellular proteins were removed with trypsin or beta-glucanase, and then all proteins/peptides were purified by solid-phase extraction, spin dialysis, and HPLC, and identified by liquid chromatography-mass spectrometry. This study identified 29 extracellular proteins with a predicted N-terminal signal sequence and also a predicted glycosylphosphatidylinositol anchor motif in more than half. Among the novel proteins identified were five glycosylphosphatidylinositol-anchored proteins with extensive Ser/Thr-rich regions but no apparent functional domains, a glycosylphosphatidylinositol-anchored aspartic protease, and a metalloprotease with structural similarity to an elastinolytic metalloprotease of Aspergillus fumigatus. This study suggests that Cry. neoformans has the machinery required to target glycosylphosphatidylinositol-anchored proteins to the cell wall, and it confirms the extracellular proteolytic ability of Cry. neoformans.

  1. Stable cosmology in chameleon bigravity

    Science.gov (United States)

    De Felice, Antonio; Mukohyama, Shinji; Oliosi, Michele; Watanabe, Yota

    2018-02-01

    The recently proposed chameleonic extension of bigravity theory, by including a scalar field dependence in the graviton potential, avoids several fine-tunings found to be necessary in usual massive bigravity. In particular it ensures that the Higuchi bound is satisfied at all scales, that no Vainshtein mechanism is needed to satisfy Solar System experiments, and that the strong coupling scale is always above the scale of cosmological interest all the way up to the early Universe. This paper extends the previous work by presenting a stable example of cosmology in the chameleon bigravity model. We find a set of initial conditions and parameters such that the derived stability conditions on general flat Friedmann background are satisfied at all times. The evolution goes through radiation-dominated, matter-dominated, and de Sitter eras. We argue that the parameter space allowing for such a stable evolution may be large enough to encompass an observationally viable evolution. We also argue that our model satisfies all known constraints due to gravitational wave observations so far and thus can be considered as a unique testing ground of gravitational wave phenomenologies in bimetric theories of gravity.

  2. Stable Heavy Hadrons in ATLAS

    CERN Document Server

    Mackeprang, Rasmus

    2007-01-01

    Several extensions to the SM feature heavy long-lived particles with masses of O(10^2-10^3 GeV) and mean lifetimes fulfilling $CT \\geq 10m$. Among such theories are supersymmetric scenarios as well as extra-dimensional models in which the heavy new particles are seen as Kaluza-Klein excitations of the well-known SM particles. Such particles will, from the point of view of a collider experiment be seen as stable. This thesis is concerned with the case where the exotic heavy particles emph{can} be considered stable while traversing the detector. Specifically the case is considered where the particles in question carry the charge of the strong nuclear force, commonly referred to as emph{colour charge}. A simulation kit has been developed using GEANT4. This framework is the current standard in experimental particle physics for the simulation of interactions of particles with matter, and it is used extensively for detector simulation. The simulation describes the interactions of these particles with matter which i...

  3. Imaging hydrated microbial extracellular polymers: Comparative analysis by electron microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Dohnalkova, A.C.; Marshall, M. J.; Arey, B. W.; Williams, K. H.; Buck, E. C.; Fredrickson, J. K.

    2011-01-01

    Microbe-mineral and -metal interactions represent a major intersection between the biosphere and geosphere but require high-resolution imaging and analytical tools for investigating microscale associations. Electron microscopy has been used extensively for geomicrobial investigations and although used bona fide, the traditional methods of sample preparation do not preserve the native morphology of microbiological components, especially extracellular polymers. Herein, we present a direct comparative analysis of microbial interactions using conventional electron microscopy approaches of imaging at room temperature and a suite of cryogenic electron microscopy methods providing imaging in the close-to-natural hydrated state. In situ, we observed an irreversible transformation of the hydrated bacterial extracellular polymers during the traditional dehydration-based sample preparation that resulted in their collapse into filamentous structures. Dehydration-induced polymer collapse can lead to inaccurate spatial relationships and hence could subsequently affect conclusions regarding nature of interactions between microbial extracellular polymers and their environment.

  4. Extracellular matrix as a driver for lung regeneration.

    Science.gov (United States)

    Balestrini, Jenna L; Niklason, Laura E

    2015-03-01

    Extracellular matrix has manifold roles in tissue mechanics, guidance of cellular behavior, developmental biology, and regenerative medicine. Over the past several decades, various pre-clinical and clinical studies have shown that many connective tissues may be replaced and/or regenerated using suitable extracellular matrix scaffolds. More recently, decellularization of lung tissue has shown that gentle removal of cells can leave behind a "footprint" within the matrix that may guide cellular adhesion, differentiation and homing following cellular repopulation. Fundamental issues like understanding matrix composition and micro-mechanics remain difficult to tackle, largely because of a lack of available assays and tools for systematically characterizing intact matrix from tissues and organs. This review will critically examine the role of engineered and native extracellular matrix in tissue and lung regeneration, and provide insights into directions for future research and translation.

  5. ISEV position paper: extracellular vesicle RNA analysis and bioinformatics

    Directory of Open Access Journals (Sweden)

    Andrew F. Hill

    2013-12-01

    Full Text Available Extracellular vesicles (EVs are the collective term for the various vesicles that are released by cells into the extracellular space. Such vesicles include exosomes and microvesicles, which vary by their size and/or protein and genetic cargo. With the discovery that EVs contain genetic material in the form of RNA (evRNA has come the increased interest in these vesicles for their potential use as sources of disease biomarkers and potential therapeutic agents. Rapid developments in the availability of deep sequencing technologies have enabled the study of EV-related RNA in detail. In October 2012, the International Society for Extracellular Vesicles (ISEV held a workshop on “evRNA analysis and bioinformatics.” Here, we report the conclusions of one of the roundtable discussions where we discussed evRNA analysis technologies and provide some guidelines to researchers in the field to consider when performing such analysis.

  6. Multistability in a neuron model with extracellular potassium dynamics

    Science.gov (United States)

    Wu, Xing-Xing; Shuai, J. W.

    2012-06-01

    Experiments show a primary role of extracellular potassium concentrations in neuronal hyperexcitability and in the generation of epileptiform bursting and depolarization blocks without synaptic mechanisms. We adopt a physiologically relevant hippocampal CA1 neuron model in a zero-calcium condition to better understand the function of extracellular potassium in neuronal seizurelike activities. The model neuron is surrounded by interstitial space in which potassium ions are able to accumulate. Potassium currents, Na+-K+ pumps, glial buffering, and ion diffusion are regulatory mechanisms of extracellular potassium. We also consider a reduced model with a fixed potassium concentration. The bifurcation structure and spiking frequency of the two models are studied. We show that, besides hyperexcitability and bursting pattern modulation, the potassium dynamics can induce not only bistability but also tristability of different firing patterns. Our results reveal the emergence of the complex behavior of multistability due to the dynamical [K+]o modulation on neuronal activities.

  7. Extracellular DNA as matrix component in microbial biofilms

    DEFF Research Database (Denmark)

    Chiang, Wen-Chi; Tolker-Nielsen, Tim

    2010-01-01

    Bacteria in nature primarily live in surface-associated communities commonly known as biofilms. Because bacteria in biofilms, in many cases, display tolerance to host immune systems, antibiotics, and biocides, they are often difficult or impossible to eradicate. Biofilm formation, therefore, leads...... to various persistent infections in humans and animals, and to a variety of complications in industry, where solid–water interfaces occur. Knowledge about the molecular mechanisms involved in biofilm formation is necessary for creating strategies to control biofilms. Recent studies have shown...... that extracellular DNA is an important component of the extracellular matrix of microbial biofilms. The present chapter is focussed on extracellular DNA as matrix component in biofilms formed by Pseudomonas aeruginosa as an example from the Gram-negative bacteria, and Streptococcus and Staphylococcus as examples...

  8. Gap junction modulation by extracellular signaling molecules: the thymus model

    Directory of Open Access Journals (Sweden)

    Alves L.A.

    2000-01-01

    Full Text Available Gap junctions are intercellular channels which connect adjacent cells and allow direct exchange of molecules of low molecular weight between them. Such a communication has been described as fundamental in many systems due to its importance in coordination, proliferation and differentiation. Recently, it has been shown that gap junctional intercellular communication (GJIC can be modulated by several extracellular soluble factors such as classical hormones, neurotransmitters, interleukins, growth factors and some paracrine substances. Herein, we discuss some aspects of the general modulation of GJIC by extracellular messenger molecules and more particularly the regulation of such communication in the thymus gland. Additionally, we discuss recent data concerning the study of different neuropeptides and hormones in the modulation of GJIC in thymic epithelial cells. We also suggest that the thymus may be viewed as a model to study the modulation of gap junction communication by different extracellular messengers involved in non-classical circuits, since this organ is under bidirectional neuroimmunoendocrine control.

  9. Extracellular Protease Activity of Enteropathogenic Escherechia coli on Mucin Substrate

    Directory of Open Access Journals (Sweden)

    SRI BUDIARTI

    2007-03-01

    Full Text Available Enteropathogenic Escherichia coli (EPEC causes gastrointestinal infections in human. EPEC invasion was initiated by attachment and aggressive colonization on intestinal surface. Attachment of EPEC alter the intestine mucosal cells. Despite this, the pathogenic mechanism of EPEC infectior has not been fully understood. This research hypothesizes that extracellular proteolytic enzymes is necessary for EPEC colonization. The enzyme is secreted into gastrointestinal milieu and presumably destroy mucus layer cover the gastrointestinal tract. The objective of this study was to assay EPEC extracellular protease enzyme by using mucin substrate. The activity of EPEC extracellular proteolytic enzyme on 1% mucin substrate was investigated. Non-pathogenic E. coli was used as a negative control. Positive and tentative controls were Yersinia enterocolitica and Salmonella. Ten EPEC strains were assayed, seven of them were able to degrade mucin, and the highest activity was produced by K1.1 strain. Both positive and tentative controls also showed the ability to digest 0.20% mucin.

  10. Production, purification, and characterization of an extracellular acid protease from the marine Antarctic yeast Rhodotorula mucilaginosa L7.

    Science.gov (United States)

    Lario, Luciana Daniela; Chaud, Luciana; Almeida, María das Graças; Converti, Attilio; Durães Sette, Lara; Pessoa, Adalberto

    2015-11-01

    The production, purification, and characterization of an extracellular protease released by Rhodotorula mucilaginosa L7 were evaluated in this study. This strain was isolated from an Antarctic marine alga and previously selected among others based on the capacity to produce the highest extracellular proteolytic activity in preliminary tests. R. mucilaginosa L7 was grown in Saboraud-dextrose medium at 25 °C, and the cell growth, pH of the medium, extracellular protease production and the glucose and protein consumption were determined as a function of time. The protease was then purified, and the effects of pH, temperature, and salt concentration on the catalytic activity and enzyme stability were determined. Enzyme production started at the beginning of the exponential phase of growth and reached a maximum after 48 h, which was accompanied by a decrease in the pH as well as reductions of the protein and glucose concentrations in the medium. The purified protease presented optimal catalytic activity at pH 5.0 and 50 °C. Finally, the enzyme was stable in the presence of high concentrations of NaCl. These characteristics are of interest for future studies and may lead to potential biotechnological applications that require enzyme activity and stability under acidic conditions and/or high salt concentrations. Copyright © 2015 The British Mycological Society. Published by Elsevier Ltd. All rights reserved.

  11. Extracellular cell wall β(1,3)glucan is required to couple septation to actomyosin ring contraction

    Science.gov (United States)

    Muñoz, Javier; Cortés, Juan Carlos G.; Sipiczki, Matthias; Ramos, Mariona; Clemente-Ramos, José Angel; Moreno, M. Belén; Martins, Ivone M.; Pérez, Pilar

    2013-01-01

    Cytokinesis has been extensively studied in different models, but the role of the extracellular cell wall is less understood. Here we studied this process in fission yeast. The essential protein Bgs4 synthesizes the main cell wall β(1,3)glucan. We show that Bgs4-derived β(1,3)glucan is required for correct and stable actomyosin ring positioning in the cell middle, before the start of septum formation and anchorage to the cell wall. Consequently, β(1,3)glucan loss generated ring sliding, oblique positioned rings and septa, misdirected septum synthesis indicative of relaxed rings, and uncoupling between a fast ring and membrane ingression and slow septum synthesis, suggesting that cytokinesis can progress with defective septum pushing and/or ring pulling forces. Moreover, Bgs4-derived β(1,3)glucan is essential for secondary septum formation and correct primary septum completion. Therefore, our results show that extracellular β(1,3)glucan is required for cytokinesis to connect the cell wall with the plasma membrane and for contractile ring function, as proposed for the equivalent extracellular matrix in animal cells. PMID:24165938

  12. Neutrophil extracellular traps promote deep vein thrombosis in mice

    Science.gov (United States)

    Brill, A.; Fuchs, T.A.; Savchenko, A.S.; Thomas, G.M.; Martinod, K.; De Meyer, S.F.; Bhandari, A.A.; Wagner, D.D.

    2011-01-01

    Summary Background Upon activation, neutrophils can release nuclear material known as neutrophil extracellular traps (NETs), which were initially described as a part of antimicrobial defense. Extracellular chromatin was recently reported to be pro-thrombotic in vitro and to accumulate in plasma and thrombi of baboons with experimental deep vein thrombosis (DVT). Objective To explore the source and role of extracellular chromatin in DVT. Methods We used an established murine model of DVT induced by flow restriction (stenosis) in the inferior vena cava (IVC). Results We demonstrate that the levels of extracellular DNA increase in plasma after 6 h IVC stenosis, compared to sham-operated mice. Immunohistochemical staining revealed the presence of Gr-1-positive neutrophils in both red (RBC-rich) and white (platelet-rich) parts of thrombi. Citrullinated histone H3 (CitH3), an element of NETs’ structure, was present only in the red part of thrombi and was frequently associated with the Gr-1 antigen. Immunofluorescent staining of thrombi showed proximity of extracellular CitH3 and von Willebrand factor (VWF), a platelet adhesion molecule crucial for thrombus development in this model. Infusion of Deoxyribonuclease 1 (DNase 1) protected mice from DVT after 6 h and also 48 h IVC stenosis. Infusion of an unfractionated mixture of calf thymus histones increased plasma VWF and promoted DVT early after stenosis application. Conclusions Extracellular chromatin, likely originating from neutrophils, is a structural part of a venous thrombus and both the DNA scaffold and histones appear to contribute to the pathogenesis of DVT in mice. NETs may provide new targets for DVT drug development. PMID:22044575

  13. Brain Extracellular Space: The Final Frontier of Neuroscience.

    Science.gov (United States)

    Nicholson, Charles; Hrabětová, Sabina

    2017-11-21

    Brain extracellular space is the narrow microenvironment that surrounds every cell of the central nervous system. It contains a solution that closely resembles cerebrospinal fluid with the addition of extracellular matrix molecules. The space provides a reservoir for ions essential to the electrical activity of neurons and forms an intercellular chemical communication channel. Attempts to reveal the size and structure of the extracellular space using electron microscopy have had limited success; however, a biophysical approach based on diffusion of selected probe molecules has proved useful. A point-source paradigm, realized in the real-time iontophoresis method using tetramethylammonium, as well as earlier radiotracer methods, have shown that the extracellular space occupies ∼20% of brain tissue and small molecules have an effective diffusion coefficient that is two-fifths that in a free solution. Monte Carlo modeling indicates that geometrical constraints, including dead-space microdomains, contribute to the hindrance to diffusion. Imaging the spread of macromolecules shows them increasingly hindered as a function of size and suggests that the gaps between cells are predominantly ∼40 nm with wider local expansions that may represent dead-spaces. Diffusion measurements also characterize interactions of ions and proteins with the chondroitin and heparan sulfate components of the extracellular matrix; however, the many roles of the matrix are only starting to become apparent. The existence and magnitude of bulk flow and the so-called glymphatic system are topics of current interest and controversy. The extracellular space is an exciting area for research that will be propelled by emerging technologies. Copyright © 2017 Biophysical Society. Published by Elsevier Inc. All rights reserved.

  14. Focus on Extracellular Vesicles: Physiological Role and Signalling Properties of Extracellular Membrane Vesicles

    Directory of Open Access Journals (Sweden)

    Nunzio Iraci

    2016-02-01

    Full Text Available Extracellular vesicles (EVs are a heterogeneous population of secreted membrane vesicles, with distinct biogenesis routes, biophysical properties and different functions both in physiological conditions and in disease. The release of EVs is a widespread biological process, which is conserved across species. In recent years, numerous studies have demonstrated that several bioactive molecules are trafficked with(in EVs, such as microRNAs, mRNAs, proteins and lipids. The understanding of their final impact on the biology of specific target cells remains matter of intense debate in the field. Also, EVs have attracted great interest as potential novel cell-free therapeutics. Here we describe the proposed physiological and pathological functions of EVs, with a particular focus on their molecular content. Also, we discuss the advances in the knowledge of the mechanisms regulating the secretion of EV-associated molecules and the specific pathways activated upon interaction with the target cell, highlighting the role of EVs in the context of the immune system and as mediators of the intercellular signalling in the brain.

  15. Extracellular DNA and lipoteichoic acids interact with exopolysaccharides in the extracellular matrix of Streptococcus mutans biofilms

    Science.gov (United States)

    Castillo Pedraza, Midian C.; Novais, Tatiana F.; Faustoferri, Roberta C.; Quivey, Robert G.; Terekhov, Anton; Hamaker, Bruce R.; Klein, Marlise I.

    2018-01-01

    Streptococcus mutans -derived exopolysaccharides are virulence determinants in the matrix of biofilms that cause caries. Extracellular DNA (eDNA) and lipoteichoic acid (LTA) are found in cariogenic biofilms, but their functions are unclear. Therefore, strains of S. mutans carrying single deletions that would modulate matrix components were used: eDNA – ΔlytS and ΔlytT; LTA – ΔdltA and ΔdltD; and insoluble exopolysaccharide – ΔgtfB. Single-species (parental strain S. mutans UA159 or individual mutant strains) and mixed-species (UA159 or mutant strain, Actinomyces naeslundii and Streptococcus gordonii) biofilms were evaluated. Distinct amounts of matrix components were detected, depending on the inactivated gene. eDNA was found to be cooperative with exopolysaccharide in early phases, while LTA played a larger role in the later phases of biofilm development. The architecture of mutant strains biofilms was distinct (vs UA159), demonstrating that eDNA and LTA influence exopolysaccharide distribution and microcolony organization. Thus, eDNA and LTA may shape exopolysaccharide structure, affecting strategies for controlling pathogenic biofilms. PMID:28946780

  16. Extracellular DNA and lipoteichoic acids interact with exopolysaccharides in the extracellular matrix of Streptococcus mutans biofilms.

    Science.gov (United States)

    Castillo Pedraza, Midian C; Novais, Tatiana F; Faustoferri, Roberta C; Quivey, Robert G; Terekhov, Anton; Hamaker, Bruce R; Klein, Marlise I

    2017-10-01

    Streptococcus mutans-derived exopolysaccharides are virulence determinants in the matrix of biofilms that cause caries. Extracellular DNA (eDNA) and lipoteichoic acid (LTA) are found in cariogenic biofilms, but their functions are unclear. Therefore, strains of S. mutans carrying single deletions that would modulate matrix components were used: eDNA - ∆lytS and ∆lytT; LTA - ∆dltA and ∆dltD; and insoluble exopolysaccharide - ΔgtfB. Single-species (parental strain S. mutans UA159 or individual mutant strains) and mixed-species (UA159 or mutant strain, Actinomyces naeslundii and Streptococcus gordonii) biofilms were evaluated. Distinct amounts of matrix components were detected, depending on the inactivated gene. eDNA was found to be cooperative with exopolysaccharide in early phases, while LTA played a larger role in the later phases of biofilm development. The architecture of mutant strains biofilms was distinct (vs UA159), demonstrating that eDNA and LTA influence exopolysaccharide distribution and microcolony organization. Thus, eDNA and LTA may shape exopolysaccharide structure, affecting strategies for controlling pathogenic biofilms.

  17. Stable isotope mass spectrometry in petroleum exploration

    International Nuclear Information System (INIS)

    Mathur, Manju

    1997-01-01

    The stable isotope mass spectrometry plays an important role to evaluate the stable isotopic composition of hydrocarbons. The isotopic ratios of certain elements in petroleum samples reflect certain characteristics which are useful for petroleum exploration

  18. Extracellular Electron Uptake: Among Autotrophs and Mediated by Surfaces

    DEFF Research Database (Denmark)

    Tremblay, Pier-Luc; Angenent, Largus T.; Zhang, Tian

    2017-01-01

    Autotrophic microbes can acquire electrons from solid donors such as steel, other microbial cells, or electrodes. Based on this feature, bioprocesses are being developed for the microbial electrosynthesis (MES) of useful products from the greenhouse gas CO2. Extracellular electron-transfer mechan......Autotrophic microbes can acquire electrons from solid donors such as steel, other microbial cells, or electrodes. Based on this feature, bioprocesses are being developed for the microbial electrosynthesis (MES) of useful products from the greenhouse gas CO2. Extracellular electron......; or (iii) mediator-generating enzymes detached from cells. This review explores the interactions of autotrophs with solid electron donors and their importance in nature and for biosustainable technologies....

  19. Syndecans as receptors and organizers of the extracellular matrix

    DEFF Research Database (Denmark)

    Xian, Xiaojie; Gopal, Sandeep; Couchman, John

    2009-01-01

    , the collagens and glycoproteins of the extracellular matrix are prominent. Frequently, they do so in conjunction with other receptors, most notably the integrins. For this reason, they are often referred to as "co-receptors". However, just as with integrins, syndecans can interact with actin-associated proteins...... and signalling molecules, such as protein kinases. Some aspects of syndecan signalling are understood but much remains to be learned. The functions of syndecans in regulating cell adhesion and extracellular matrix assembly are described here. Evidence from null mice suggests that syndecans have roles...

  20. Production of extracellular fatty acid using engineered Escherichia coli

    Directory of Open Access Journals (Sweden)

    Liu Hui

    2012-04-01

    Full Text Available Abstract Background As an alternative for economic biodiesel production, the microbial production of extracellular fatty acid from renewable resources is receiving more concerns recently, since the separation of fatty acid from microorganism cells is normally involved in a series of energy-intensive steps. Many attempts have been made to construct fatty acid producing strains by targeting genes in the fatty acid biosynthetic pathway, while few studies focused on the cultivation process and the mass transfer kinetics. Results In this study, both strain improvements and cultivation process strategies were applied to increase extracellular fatty acid production by engineered Escherichia coli. Our results showed overexpressing ‘TesA and the deletion of fadL in E. coli BL21 (DE3 improved extracellular fatty acid production, while deletion of fadD didn’t strengthen the extracellular fatty acid production for an undetermined mechanism. Moreover, the cultivation process controls contributed greatly to extracellular fatty acid production with respect to titer, cell growth and productivity by adjusting the temperature, adding ampicillin and employing on-line extraction. Under optimal conditions, the E. coli strain (pACY-‘tesA-ΔfadL produced 4.8 g L−1 extracellular fatty acid, with the specific productivity of 0.02 g h−1 g−1dry cell mass, and the yield of 4.4% on glucose, while the ratios of cell-associated fatty acid versus extracellular fatty acid were kept below 0.5 after 15 h of cultivation. The fatty acids included C12:1, C12:0, C14:1, C14:0, C16:1, C16:0, C18:1, C18:0. The composition was dominated by C14 and C16 saturated and unsaturated fatty acids. Using the strain pACY-‘tesA, similar results appeared under the same culture conditions and the titer was also much higher than that ever reported previously, which suggested that the supposedly superior strain did not necessarily perform best for the efficient production of desired

  1. Stable rotating dipole solitons in nonlocal media

    DEFF Research Database (Denmark)

    Lopez-Aguayo, Servando; Skupin, Stefan; Desyatnikov, Anton S.

    2006-01-01

    We present the first example of stable rotating two-soliton bound states in nonlinear optical media with nonlocal response. We show that, in contrast to media with local response, nonlocality opens possibilities to generate stable azimuthons.......We present the first example of stable rotating two-soliton bound states in nonlinear optical media with nonlocal response. We show that, in contrast to media with local response, nonlocality opens possibilities to generate stable azimuthons....

  2. Tempered stable laws as random walk limits

    OpenAIRE

    Chakrabarty, Arijit; Meerschaert, Mark M.

    2010-01-01

    Stable laws can be tempered by modifying the L\\'evy measure to cool the probability of large jumps. Tempered stable laws retain their signature power law behavior at infinity, and infinite divisibility. This paper develops random walk models that converge to a tempered stable law under a triangular array scheme. Since tempered stable laws and processes are useful in statistical physics, these random walk models can provide a basic physical model for the underlying physical phenomena.

  3. Stable States of Biological Organisms

    Science.gov (United States)

    Yukalov, V. I.; Sornette, D.; Yukalova, E. P.; Henry, J.-Y.; Cobb, J. P.

    2009-04-01

    A novel model of biological organisms is advanced, treating an organism as a self-consistent system subject to a pathogen flux. The principal novelty of the model is that it describes not some parts, but a biological organism as a whole. The organism is modeled by a five-dimensional dynamical system. The organism homeostasis is described by the evolution equations for five interacting components: healthy cells, ill cells, innate immune cells, specific immune cells, and pathogens. The stability analysis demonstrates that, in a wide domain of the parameter space, the system exhibits robust structural stability. There always exist four stable stationary solutions characterizing four qualitatively differing states of the organism: alive state, boundary state, critical state, and dead state.

  4. Super-stable Poissonian structures

    International Nuclear Information System (INIS)

    Eliazar, Iddo

    2012-01-01

    In this paper we characterize classes of Poisson processes whose statistical structures are super-stable. We consider a flow generated by a one-dimensional ordinary differential equation, and an ensemble of particles ‘surfing’ the flow. The particles start from random initial positions, and are propagated along the flow by stochastic ‘wave processes’ with general statistics and general cross correlations. Setting the initial positions to be Poisson processes, we characterize the classes of Poisson processes that render the particles’ positions—at all times, and invariantly with respect to the wave processes—statistically identical to their initial positions. These Poisson processes are termed ‘super-stable’ and facilitate the generalization of the notion of stationary distributions far beyond the realm of Markov dynamics. (paper)

  5. Super-stable Poissonian structures

    Science.gov (United States)

    Eliazar, Iddo

    2012-10-01

    In this paper we characterize classes of Poisson processes whose statistical structures are super-stable. We consider a flow generated by a one-dimensional ordinary differential equation, and an ensemble of particles ‘surfing’ the flow. The particles start from random initial positions, and are propagated along the flow by stochastic ‘wave processes’ with general statistics and general cross correlations. Setting the initial positions to be Poisson processes, we characterize the classes of Poisson processes that render the particles’ positions—at all times, and invariantly with respect to the wave processes—statistically identical to their initial positions. These Poisson processes are termed ‘super-stable’ and facilitate the generalization of the notion of stationary distributions far beyond the realm of Markov dynamics.

  6. Periodicity of the stable isotopes

    CERN Document Server

    Boeyens, J C A

    2003-01-01

    It is demonstrated that all stable (non-radioactive) isotopes are formally interrelated as the products of systematically adding alpha particles to four elementary units. The region of stability against radioactive decay is shown to obey a general trend based on number theory and contains the periodic law of the elements as a special case. This general law restricts the number of what may be considered as natural elements to 100 and is based on a proton:neutron ratio that matches the golden ratio, characteristic of biological and crystal growth structures. Different forms of the periodic table inferred at other proton:neutron ratios indicate that the electronic configuration of atoms is variable and may be a function of environmental pressure. Cosmic consequences of this postulate are examined. (author)

  7. Stable massive particles at colliders

    Energy Technology Data Exchange (ETDEWEB)

    Fairbairn, M.; /Stockholm U.; Kraan, A.C.; /Pennsylvania U.; Milstead, D.A.; /Stockholm U.; Sjostrand, T.; /Lund U.; Skands, P.; /Fermilab; Sloan, T.; /Lancaster U.

    2006-11-01

    We review the theoretical motivations and experimental status of searches for stable massive particles (SMPs) which could be sufficiently long-lived as to be directly detected at collider experiments. The discovery of such particles would address a number of important questions in modern physics including the origin and composition of dark matter in the universe and the unification of the fundamental forces. This review describes the techniques used in SMP-searches at collider experiments and the limits so far obtained on the production of SMPs which possess various colour, electric and magnetic charge quantum numbers. We also describe theoretical scenarios which predict SMPs, the phenomenology needed to model their production at colliders and interactions with matter. In addition, the interplay between collider searches and open questions in cosmology such as dark matter composition are addressed.

  8. The Myopic Stable Set for Social Environments

    NARCIS (Netherlands)

    Demuynck, Thomas; Herings, P. Jean-Jacques; Saulle, Riccardo; Seel, Christian

    2017-01-01

    We introduce a new solution concept for models of coalition formation, called the myopic stable set. The myopic stable set is defined for a very general class of social environments and allows for an infinite state space. We show that the myopic stable set exists and is non-empty. Under minor

  9. Effectiveness and risks of stable iodine prophylaxis

    International Nuclear Information System (INIS)

    Waight, P.J.

    1995-01-01

    The factors upon which the efficacy of stable iodine prophylaxis depends are reviewed, with particular reference to the dose of stable iodine, the timing of the dose, the influence of dietary iodine and the impact of the other prospective actions. The risks of stable iodine ingestion are estimated, and their application to the principle of Justification in outlined. (Author)

  10. Temperature and Humidity Control in Livestock Stables

    DEFF Research Database (Denmark)

    Hansen, Michael; Andersen, Palle; Nielsen, Kirsten M.

    2010-01-01

    The paper describes temperature and humidity control of a livestock stable. It is important to have a correct air flow pattern in the livestock stable in order to achieve proper temperature and humidity control as well as to avoid draught. In the investigated livestock stable the air flow...

  11. Crystallization and preliminary crystallographic analysis of Gibberella zeae extracellular lipase

    International Nuclear Information System (INIS)

    Sun, Yuna; Li, Ming; Zhang, Yan; Liu, Lifang; Liu, Ye; Liu, Zheng; Li, Xumei; Lou, Zhiyong

    2008-01-01

    G. zeae extracellular lipase has been overexpressed, purified and crystallized. Diffraction data were collected to 2.8 Å resolution. Fusarium head blight, one of the most destructive crop diseases, is mainly caused by Fusarium graminearum (known in its sexual stage as Gibberella zeae). F. graminearum secretes various extracellular enzymes that have been hypothesized to be involved in host infection. One of the extracellular enzymes secreted by this organism is the G. zeae extracellular lipase (GZEL), which is encoded by the FGL1 gene. In order to solve the crystal structure of GZEL and to gain a better understanding of the biological functions of the protein and of possible inhibitory mechanisms of lipase inhibitors, recombinant GZEL was crystallized at 291 K using PEG 3350 as a precipitant. A data set was collected to 2.8 Å resolution from a single flash-cooled crystal (100 K). The crystal belonged to space group P2 1 2 1 2 1 , with unit-cell parameters a = 78.4, b = 91.0, c = 195.8 Å, α = β = γ = 90°. The presence of four molecules was assumed per asymmetric unit, which gave a Matthews coefficient of 2.6 Å 3 Da −1

  12. Filtration recovery of extracellular DNA from environmental water samples

    Science.gov (United States)

    qPCR methods are able to analyze DNA from microbes within hours of collecting water samples, providing the promptest notification and public awareness possible when unsafe pathogenic levels are reached. Health risk, however, may be overestimated by the presence of extracellular ...

  13. Glycosylation of extracellular vesicles : current knowledge, tools and clinical perspectives

    NARCIS (Netherlands)

    Williams, Charles; Royo, Felix; Aizpurua-Olaizola, Oier; Pazos, Raquel; Boons, Geert-Jan; Reichardt, Niels-Christian; Falcon-Perez, Juan M

    2018-01-01

    It is now acknowledged that extracellular vesicles (EVs) are important effectors in a vast number of biological processes through intercellular transfer of biomolecules. Increasing research efforts in the EV field have yielded an appreciation for the potential role of glycans in EV function. Indeed,

  14. Extracellular protease produced by Bacillus subtilis isolated from ...

    African Journals Online (AJOL)

    In a study to evaluate the microbiological safety of some paracetamol oral solutions sold in some Nigerian drug stores, 40.0% of the samples examined was contaminated with protease-producing Bacillus subtilis. The production of extracellular protease was induced by casein in the minimal medium and was found to be the ...

  15. Extracellular Membrane Vesicles and Phytopathogenicity of Acholeplasma laidlawii PG8

    Directory of Open Access Journals (Sweden)

    Vladislav M. Chernov

    2012-01-01

    Full Text Available For the first time, the phytopathogenicity of extracellular vesicles of Acholeplasma laidlawii PG8 (a ubiquitous mycoplasma that is one of the five common species of cell culture contaminants and is a causative agent for phytomycoplasmoses in Oryza sativa L. plants was studied. Data on the ability of extracellular vesicles of Acholeplasma laidlawii PG8 to penetrate from the nutrient medium into overground parts of Oryza sativa L. through the root system and to cause alterations in ultrastructural organization of the plants were presented. As a result of the analysis of ultrathin leaf sections of plants grown in medium with A. laidlawii PG8 vesicles, we detected significant changes in tissue ultrastructure characteristic to oxidative stress in plants as well as their cultivation along with bacterial cells. The presence of nucleotide sequences of some mycoplasma genes within extracellular vesicles of Acholeplasma laidlawii PG8 allowed a possibility to use PCR (with the following sequencing to perform differential detection of cells and bacterial vesicles in samples under study. The obtained data may suggest the ability of extracellular vesicles of the mycoplasma to display in plants the features of infection from the viewpoint of virulence criteria—invasivity, infectivity—and toxigenicity—and to favor to bacterial phytopathogenicity.

  16. Optimization of culture media for extracellular expression of ...

    African Journals Online (AJOL)

    Purpose: To investigate the enhancement of streptokinase extracellular expression in Escherichia coli by adjusting culture media. Methods: Screening of 10 chemical factors (EDTA, peptone, glycine, triton X-100, glycerol, K2HPO4,. KH2PO4, Ca2+ (calcium chloride), yeast and NaCl) in order to increase the secretion of ...

  17. Immunological and biochemical characterization of extracellular polysaccharides of mucoralean moulds

    NARCIS (Netherlands)

    Ruiter, de G.A.

    1993-01-01

    In this thesis the characterization is described of the antigenic determinants (epitopes) of the extracellular polysaccharides (EPSs) from moulds belonging to the order of Mucorales. Detailed knowledge of the structure of these epitopes allows for further development of a new generation of

  18. Brain washing : Transport of cerebral extracellular fluids and solutes

    NARCIS (Netherlands)

    Bedussi, B.

    2017-01-01

    Regulation of extracellular volume and fluid composition provides a robust microenvironment for brain cells. In peripheral tissue, fluid surplus and solutes are removed from the interstitium via drainage into lymphatic channels. Since the central nervous system lacks a proper lymphatic vasculature,

  19. Extracellular matrix components direct porcine muscle stem cell behavior

    International Nuclear Information System (INIS)

    Wilschut, Karlijn J.; Haagsman, Henk P.; Roelen, Bernard A.J.

    2010-01-01

    In muscle tissue, extracellular matrix proteins, together with the vasculature system, muscle-residence cells and muscle fibers, create the niche for muscle stem cells. The niche is important in controlling proliferation and directing differentiation of muscle stem cells to sustain muscle tissue. Mimicking the extracellular muscle environment improves tools exploring the behavior of primary muscle cells. Optimizing cell culture conditions to maintain muscle commitment is important in stem cell-based studies concerning toxicology screening, ex vivo skeletal muscle tissue engineering and in the enhancement of clinical efficiency. We used the muscle extracellular matrix proteins collagen type I, fibronectin, laminin, and also gelatin and Matrigel as surface coatings of tissue culture plastic to resemble the muscle extracellular matrix. Several important factors that determine myogenic commitment of the primary muscle cells were characterized by quantitative real-time RT-PCR and immunofluorescence. Adhesion of high PAX7 expressing satellite cells was improved if the cells were cultured on fibronectin or laminin coatings. Cells cultured on Matrigel and laminin coatings showed dominant integrin expression levels and exhibited an activated Wnt pathway. Under these conditions both stem cell proliferation and myogenic differentiation capacity were superior if compared to cells cultured on collagen type I, fibronectin and gelatin. In conclusion, Matrigel and laminin are the preferred coatings to sustain the proliferation and myogenic differentiation capacity of the primary porcine muscle stem cells, when cells are removed from their natural environment for in vitro culture.

  20. Integration of concepts: cardiac extracellular matrix remodeling after myocardial infarction

    NARCIS (Netherlands)

    Cleutjens, Jack P. M.; Creemers, Esther E. J. M.

    2002-01-01

    The cardiac extracellular matrix consists of a three-dimensional structural network of interstitial collagens to which other matrix components are attached. The main physiological functions of this network are to retain tissue integrity and cardiac pump function. Collagen deposition is controlled

  1. Extracellular matrix proteins: a positive feedback loop in lung fibrosis?

    NARCIS (Netherlands)

    Blaauboer, M.E.; van Boeijen, F.R.; Emson, C.L.; Turner, S.M.; Zandieh-Doulabi, B.; Hanemaaijer, R.; Smit, T.H.; Stoop, R.; Everts, V.

    2014-01-01

    Lung fibrosis is characterized by excessive deposition of extracellular matrix. This not only affects tissue architecture and function, but it also influences fibroblast behavior and thus disease progression. Here we describe the expression of elastin, type V collagen and tenascin C during the

  2. Extracellular matrix proteins: A positive feedback loop in lung fibrosis?

    NARCIS (Netherlands)

    Blaauboer, M.E.; Boeijen, F.R.; Emson, C.L.; Turner, S.M.; Zandieh-Doulabi, B.; Hanemaaijer, R.; Smit, T.H.; Stoop, R.; Everts, V.

    2014-01-01

    Lung fibrosis is characterized by excessive deposition of extracellular matrix. This not only affects tissue architecture and function, but it also influences fibroblast behavior and thus disease progression. Here we describe the expression of elastin, type V collagen and tenascin C during the

  3. Extracellular matrix components direct porcine muscle stem cell behavior

    Energy Technology Data Exchange (ETDEWEB)

    Wilschut, Karlijn J. [Department of Farm Animal Health, Faculty of Veterinary Medicine, Utrecht University, Yalelaan 104, 3584 CM, Utrecht (Netherlands); Haagsman, Henk P. [Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, Yalelaan 1, 3584 CL, Utrecht (Netherlands); Roelen, Bernard A.J., E-mail: b.a.j.roelen@uu.nl [Department of Farm Animal Health, Faculty of Veterinary Medicine, Utrecht University, Yalelaan 104, 3584 CM, Utrecht (Netherlands)

    2010-02-01

    In muscle tissue, extracellular matrix proteins, together with the vasculature system, muscle-residence cells and muscle fibers, create the niche for muscle stem cells. The niche is important in controlling proliferation and directing differentiation of muscle stem cells to sustain muscle tissue. Mimicking the extracellular muscle environment improves tools exploring the behavior of primary muscle cells. Optimizing cell culture conditions to maintain muscle commitment is important in stem cell-based studies concerning toxicology screening, ex vivo skeletal muscle tissue engineering and in the enhancement of clinical efficiency. We used the muscle extracellular matrix proteins collagen type I, fibronectin, laminin, and also gelatin and Matrigel as surface coatings of tissue culture plastic to resemble the muscle extracellular matrix. Several important factors that determine myogenic commitment of the primary muscle cells were characterized by quantitative real-time RT-PCR and immunofluorescence. Adhesion of high PAX7 expressing satellite cells was improved if the cells were cultured on fibronectin or laminin coatings. Cells cultured on Matrigel and laminin coatings showed dominant integrin expression levels and exhibited an activated Wnt pathway. Under these conditions both stem cell proliferation and myogenic differentiation capacity were superior if compared to cells cultured on collagen type I, fibronectin and gelatin. In conclusion, Matrigel and laminin are the preferred coatings to sustain the proliferation and myogenic differentiation capacity of the primary porcine muscle stem cells, when cells are removed from their natural environment for in vitro culture.

  4. Astrocytes and extracellular matrix in extrasynaptic volume transmission

    Czech Academy of Sciences Publication Activity Database

    Vargová, Lýdia; Syková, Eva

    2014-01-01

    Roč. 369, č. 1654 (2014) ISSN 0962-8436 R&D Projects: GA ČR GA13-11867S; GA ČR(CZ) GBP304/12/G069 Institutional support: RVO:68378041 Keywords : extracellular space * diffusion * astrocytes Subject RIV: FH - Neurology Impact factor: 7.055, year: 2014

  5. Sortilin mediates vascular calcification via its recruitment into extracellular vesicles

    DEFF Research Database (Denmark)

    Goettsch, Claudia; Hutscheson, JD; Aikawa, M

    2016-01-01

    obscure. Here, we have demonstrated that sortilin is a key regulator of smooth muscle cell (SMC) calcification via its recruitment to extracellular vesicles. Sortilin localized to calcifying vessels in human and mouse atheromata and participated in formation of microcalcifications in SMC culture. Sortilin...

  6. The effect of nutrients on extracellular polymeric substance ...

    African Journals Online (AJOL)

    The effect of nutrients on extracellular polymeric substance (EPS) production and its impact on sludge properties and removal efficiencies were investigated in an in-depth field survey of wastewater treatment plants. Thereafter, laboratory studies were performed to evaluate the effect of a combination of nutrients - nitrogen ...

  7. Inflammation leads to distinct populations of extracellular vesicles from microglia

    DEFF Research Database (Denmark)

    Yang, Yiyi; Boza-Serrano, Antonio; Dunning, Christopher J.R.

    2018-01-01

    Background: Activated microglia play an essential role in inflammatory responses elicited in the central nervous system (CNS). Microglia-derived extracellular vesicles (EVs) are suggested to be involved in propagation of inflammatory signals and in the modulation of cell-to-cell communication...

  8. Extracellular products of photosynthesis in a tropical environment

    Digital Repository Service at National Institute of Oceanography (India)

    Gomes, H.R.; Pant, A.

    Extracellular products in the Arabian Sea averaged 0.42 g/cm2/day and represented 35% of the total carbon fixed by phytoplankton. No seasonal changes are observed during the two seasons i.e. premonsoon (Jan-Feb) and onset of southwest monsoon (April...

  9. Nucleases from Prevotella intermedia can degrade neutrophil extracellular traps.

    Science.gov (United States)

    Doke, M; Fukamachi, H; Morisaki, H; Arimoto, T; Kataoka, H; Kuwata, H

    2017-08-01

    Periodontitis is an inflammatory disease caused by periodontal bacteria in subgingival plaque. These bacteria are able to colonize the periodontal region by evading the host immune response. Neutrophils, the host's first line of defense against infection, use various strategies to kill invading pathogens, including neutrophil extracellular traps (NETs). These are extracellular net-like fibers comprising DNA and antimicrobial components such as histones, LL-37, defensins, myeloperoxidase, and neutrophil elastase from neutrophils that disarm and kill bacteria extracellularly. Bacterial nuclease degrades the NETs to escape NET killing. It has now been shown that extracellular nucleases enable bacteria to evade this host antimicrobial mechanism, leading to increased pathogenicity. Here, we compared the DNA degradation activity of major Gram-negative periodontopathogenic bacteria, Porphyromonas gingivalis, Prevotella intermedia, Fusobacterium nucleatum, and Aggregatibacter actinomycetemcomitans. We found that Pr. intermedia showed the highest DNA degradation activity. A genome search of Pr. intermedia revealed the presence of two genes, nucA and nucD, putatively encoding secreted nucleases, although their enzymatic and biological activities are unknown. We cloned nucA- and nucD-encoding nucleases from Pr. intermedia ATCC 25611 and characterized their gene products. Recombinant NucA and NucD digested DNA and RNA, which required both Mg 2+ and Ca 2+ for optimal activity. In addition, NucA and NucD were able to degrade the DNA matrix comprising NETs. © 2016 The Authors Molecular Oral Microbiology Published by John Wiley & Sons Ltd.

  10. Neutrophil extracellular traps in patients with pulmonary tuberculosis

    NARCIS (Netherlands)

    van der Meer, Anne Jan; Zeerleder, Sacha; Blok, Dana C.; Kager, Liesbeth M.; Lede, Ivar O.; Rahman, Wahid; Afroz, Rumana; Ghose, Aniruddha; Visser, Caroline E.; Zahed, Abu Shahed Md; Husain, Md Anwar; Alam, Khan Mashrequl; Barua, Pravat Chandra; Hassan, Mahtabuddin; Tayab, Md Abu; Dondorp, Arjen M.; van der Poll, Tom

    2017-01-01

    Tuberculosis is a devastating infectious disease causing many deaths worldwide. Recent investigations have implicated neutrophil extracellular traps (NETs) in the host response to tuberculosis. The aim of the current study was to obtain evidence for NETs release in the circulation during human

  11. Extracellular β-D-fructofuranosidase from Aspergillus parasiticus ...

    African Journals Online (AJOL)

    The β-D-fructofuranosidases are enzymes with biotechnological potential that can be used in different industrial sectors as food and beverage. In this context, microorganisms are important producers of these biomolecules, especially filamentous fungi. The production of extracellular β-Dfructofuranosidase from Aspergillus ...

  12. Extracellular clusterin promotes neuronal network complexity in vitro

    DEFF Research Database (Denmark)

    Wicher, Grzegorz; Velsecchi, Isabel; Charnay, Yves

    2008-01-01

    Clusterin (apolipoprotein J), a highly conserved amphiphatic glycoprotein and chaperone, has been implicated in a wide range of physiological and pathological processes. As a secreted protein, clusterin has been shown to act extracellularly where it is involved in lipid transportation and clearan...

  13. In vivo extracellular matrix protein expression by human periodontal ...

    African Journals Online (AJOL)

    It is well known that the orthodontic force applied to teeth generates a series of events that remodel the periodontal ligament (PDL). Extracellular matrix proteins (ECM) are described as molecular regulators of these events. However, the exact contribution of these proteins in human PDL modeling by orthodontic force ...

  14. Focus on Extracellular Vesicles: Therapeutic Potential of Stem Cell-Derived Extracellular Vesicles

    Directory of Open Access Journals (Sweden)

    Bin Zhang

    2016-02-01

    Full Text Available The intense research focus on stem and progenitor cells could be attributed to their differentiation potential to generate new cells to replace diseased or lost cells in many highly intractable degenerative diseases, such as Alzheimer disease, multiple sclerosis, and heart diseases. However, experimental and clinical studies have increasingly attributed the therapeutic efficacy of these cells to their secretion. While stem and progenitor cells secreted many therapeutic molecules, none of these molecules singly or in combination could recapitulate the functional effects of stem cell transplantations. Recently, it was reported that extracellular vesicles (EVs could recapitulate the therapeutic effects of stem cell transplantation. Based on the observations reported thus far, the prevailing hypothesis is that stem cell EVs exert their therapeutic effects by transferring biologically active molecules such as proteins, lipids, mRNA, and microRNA from the stem cells to injured or diseased cells. In this respect, stem cell EVs are similar to EVs from other cell types. They are both primarily vehicles for intercellular communication. Therefore, the differentiating factor is likely due to the composition of their cargo. The cargo of EVs from different cell types are known to include a common set of proteins and also proteins that reflect the cell source of the EVs and the physiological or pathological state of the cell source. Hence, elucidation of the stem cell EV cargo would provide an insight into the multiple physiological or biochemical changes necessary to affect the many reported stem cell-based therapeutic outcomes in a variety of experimental models and clinical trials.

  15. Extracellular small heat shock proteins: exosomal biogenesis and function.

    Science.gov (United States)

    Reddy, V Sudhakar; Madala, Satish K; Trinath, Jamma; Reddy, G Bhanuprakash

    2018-05-01

    Small heat shock proteins (sHsps) belong to the family of heat shock proteins (Hsps): some are induced in response to multiple stressful events to protect the cells while others are constitutively expressed. Until now, it was believed that Hsps, including sHsps, are present inside the cells and perform intracellular functions. Interestingly, several groups recently reported the extracellular presence of Hsps, and sHsps have also been detected in sera/cerebrospinal fluids in various pathological conditions. Secretion into the extracellular milieu during many pathological conditions suggests additional or novel functions of sHsps in addition to their intracellular properties. Extracellular sHsps are implicated in cell-cell communication, activation of immune cells, and promoting anti-inflammatory and anti-platelet responses. Interestingly, exogenous administration of sHsps showed therapeutic effects in multiple disease models implying that extracellular sHsps are beneficial in pathological conditions. sHsps do not possess signal sequence and, hence, are not exported through the classical Endoplasmic reticulum-Golgi complex (ER-Golgi) secretory pathway. Further, export of sHsps is not inhibited by ER-Golgi secretory pathway inhibitors implying the involvement of a nonclassical secretory pathway in sHsp export. In lieu, lysoendosomal and exosomal pathways have been proposed for the export of sHsps. Heat shock protein 27 (Hsp27), αB-crystallin (αBC), and Hsp20 are shown to be exported by exosomes. Exosomes packaged with sHsps have beneficial effects in in vivo disease models. However, secretion mechanisms and therapeutic use of sHsps have not been elucidated in detail. Therefore, this review aimed at highlighting the current understanding of sHsps (Hsp27, αBC, and Hsp20) in the extracellular medium.

  16. Moltex Energy's stable salt reactors

    International Nuclear Information System (INIS)

    O'Sullivan, R.; Laurie, J.

    2016-01-01

    A stable salt reactor is a molten salt reactor in which the molten fuel salt is contained in fuel rods. This concept was invented in 1951 and re-discovered and improved recently by Moltex Energy Company. The main advantage of using molten salt fuel is that the 2 problematic fission products cesium and iodine do not exist in gaseous form but rather in a form of a salt that present no danger in case of accident. Another advantage is the strongly negative temperature coefficient for reactivity which means the reactor self-regulates. The feasibility studies have been performed on a molten salt fuel composed of sodium chloride and plutonium/uranium/lanthanide/actinide trichloride. The coolant fluid is a mix of sodium and zirconium fluoride salts that will need low flow rates. The addition of 1 mol% of metal zirconium to the coolant fluid reduces the risk of corrosion with standard steels and the addition of 2% of hafnium reduces the neutron dose. The temperature of the coolant is expected to reach 650 Celsius degrees at the exit of the core. This reactor is designed to be modular and it will be able to burn actinides. (A.C.)

  17. Rare stable isotopes in meteorites

    International Nuclear Information System (INIS)

    Wilson, G.C.

    1981-01-01

    Secondary Ion Mass Spectrometry (SIMS) using accelerators has been applied with success to cosmic ray exposure ages and terrestrial residence times of meteorites by measuring cosmogenic nuclides of Be, Cl, and I. It is proposed to complement this work with experiments on rare stable isotopes, in the hope of setting constraints on the processes of solar nebula/meteoritic formation. The relevant species can be classified as: a) daughter products of extinct nuclides (halflife less than or equal to 2 x 10 8 y) -chronology of the early solar system; b) products of high temperature astrophysical processes - different components incorporated into the solar nebula; and c) products of relatively low temperature processes, stellar winds and cosmic ray reactions - early solar system radiation history. The use of micron-scale primary ion beams will allow detailed sampling of phases within meteorites. Strategies of charge-state selection, molecular disintegration and detection should bring a new set of targets within analytical range. The developing accelerator field is compared to existing (keV energy) ion microprobes

  18. Stable piecewise polynomial vector fields

    Directory of Open Access Journals (Sweden)

    Claudio Pessoa

    2012-09-01

    Full Text Available Let $N={y>0}$ and $S={y<0}$ be the semi-planes of $mathbb{R}^2$ having as common boundary the line $D={y=0}$. Let $X$ and $Y$ be polynomial vector fields defined in $N$ and $S$, respectively, leading to a discontinuous piecewise polynomial vector field $Z=(X,Y$. This work pursues the stability and the transition analysis of solutions of $Z$ between $N$ and $S$, started by Filippov (1988 and Kozlova (1984 and reformulated by Sotomayor-Teixeira (1995 in terms of the regularization method. This method consists in analyzing a one parameter family of continuous vector fields $Z_{epsilon}$, defined by averaging $X$ and $Y$. This family approaches $Z$ when the parameter goes to zero. The results of Sotomayor-Teixeira and Sotomayor-Machado (2002 providing conditions on $(X,Y$ for the regularized vector fields to be structurally stable on planar compact connected regions are extended to discontinuous piecewise polynomial vector fields on $mathbb{R}^2$. Pertinent genericity results for vector fields satisfying the above stability conditions are also extended to the present case. A procedure for the study of discontinuous piecewise vector fields at infinity through a compactification is proposed here.

  19. Stable Structures for Distributed Applications

    Directory of Open Access Journals (Sweden)

    Eugen DUMITRASCU

    2008-01-01

    Full Text Available For distributed applications, we define the linear, tree and graph structure types with different variants and modalities to aggregate them. The distributed applications have assigned structures that through their characteristics influence the costs of stages for developing cycle and the costs for exploitation, transferred to each user. We also present the quality characteristics of a structure for a stable application, which is focused on stability characteristic. For that characteristic we define the estimated measure indicators for a level. The influence of the factors of stability and the ways for increasing it are thus identified, and at the same time the costs of development stages, the costs of usage and the costs of maintenance to be keep on between limits that assure the global efficiency of application. It is presented the base aspects for distributed applications: definition, peculiarities and importance. The aspects for the development cycle of distributed application are detailed. In this article, we alongside give the mechanisms for building the defined structures and analyze the complexity of the defined structures for a distributed application of a virtual store.

  20. Distribution of stable and radioactive metals among the biomass compartments of the macrophytes of the Yenisei river and estimation of the dose rate

    International Nuclear Information System (INIS)

    Zotina, T.A.; Bolsunovskiy, A.Ya.; Sukovatyj, A.G.

    2008-01-01

    Artificial radioactive metals are annually detected in the biomass of submerged macrophytes in the zone radioactive contamination of the Yenisei river. It has been shown by other authors that metals are not uniformly distributed in the biomass of aquatic macrophytes. In this research the distribution of stable and radioactive isotopes of metals was investigated among the biomass compartments of the macrophytes from the Yenisei river with chemical fractionation technique. Dose rates from the intra- and extracellular radionuclides have been estimated. According to the data obtained the distribution of metals among intra- and extracellular compartments was different. The major portion of Co, Mn and Zn was accumulated in the biomass in more mobile form, than Cr and Fe. Artificial radioactive isotopes were detected in the same compartments as stable metals. Essential portion of artificial radionuclides and stable metals was detected in the particles of seston, attached to the surface of the macrophytes.

  1. Glia and extracellular matrix changes affect extracellular diffusion and volume transmission in the brain in health and disease

    Czech Academy of Sciences Publication Activity Database

    Vargová, Lýdia; Syková, Eva

    2011-01-01

    Roč. 59, S1 (2011), S38 ISSN 0894-1491. [European meeting on Glia l Cells in Health and Disease /10./. 13.09.2011-17.09.2011, Prague] Institutional research plan: CEZ:AV0Z50390512; CEZ:AV0Z50390703 Keywords : diffusion * extracellular matrix * extrasynaptic transmission Subject RIV: FH - Neurology

  2. Meeting report: discussions and preliminary findings on extracellular RNA measurement methods from laboratories in the NIH Extracellular RNA Communication Consortium

    Directory of Open Access Journals (Sweden)

    Louise C. Laurent

    2015-08-01

    Full Text Available Extracellular RNAs (exRNAs have been identified in all tested biofluids and have been associated with a variety of extracellular vesicles, ribonucleoprotein complexes and lipoprotein complexes. Much of the interest in exRNAs lies in the fact that they may serve as signalling molecules between cells, their potential to serve as biomarkers for prediction and diagnosis of disease and the possibility that exRNAs or the extracellular particles that carry them might be used for therapeutic purposes. Among the most significant bottlenecks to progress in this field is the lack of robust and standardized methods for collection and processing of biofluids, separation of different types of exRNA-containing particles and isolation and analysis of exRNAs. The Sample and Assay Standards Working Group of the Extracellular RNA Communication Consortium is a group of laboratories funded by the U.S. National Institutes of Health to develop such methods. In our first joint endeavour, we held a series of conference calls and in-person meetings to survey the methods used among our members, placed them in the context of the current literature and used our findings to identify areas in which the identification of robust methodologies would promote rapid advancements in the exRNA field.

  3. Escaping Underground Nets: Extracellular DNases Degrade Plant Extracellular Traps and Contribute to Virulence of the Plant Pathogenic Bacterium Ralstonia solanacearum

    Science.gov (United States)

    Tran, Tuan Minh; MacIntyre, April; Hawes, Martha; Allen, Caitilyn

    2016-01-01

    Plant root border cells have been recently recognized as an important physical defense against soil-borne pathogens. Root border cells produce an extracellular matrix of protein, polysaccharide and DNA that functions like animal neutrophil extracellular traps to immobilize pathogens. Exposing pea root border cells to the root-infecting bacterial wilt pathogen Ralstonia solanacearum triggered release of DNA-containing extracellular traps in a flagellin-dependent manner. These traps rapidly immobilized the pathogen and killed some cells, but most of the entangled bacteria eventually escaped. The R. solanacearum genome encodes two putative extracellular DNases (exDNases) that are expressed during pathogenesis, suggesting that these exDNases contribute to bacterial virulence by enabling the bacterium to degrade and escape root border cell traps. We tested this hypothesis with R. solanacearum deletion mutants lacking one or both of these nucleases, named NucA and NucB. Functional studies with purified proteins revealed that NucA and NucB are non-specific endonucleases and that NucA is membrane-associated and cation-dependent. Single ΔnucA and ΔnucB mutants and the ΔnucA/B double mutant all had reduced virulence on wilt-susceptible tomato plants in a naturalistic soil-soak inoculation assay. The ΔnucA/B mutant was out-competed by the wild-type strain in planta and was less able to stunt root growth or colonize plant stems. Further, the double nuclease mutant could not escape from root border cells in vitro and was defective in attachment to pea roots. Taken together, these results demonstrate that extracellular DNases are novel virulence factors that help R. solanacearum successfully overcome plant defenses to infect plant roots and cause bacterial wilt disease. PMID:27336156

  4. Escaping Underground Nets: Extracellular DNases Degrade Plant Extracellular Traps and Contribute to Virulence of the Plant Pathogenic Bacterium Ralstonia solanacearum.

    Directory of Open Access Journals (Sweden)

    Tuan Minh Tran

    2016-06-01

    Full Text Available Plant root border cells have been recently recognized as an important physical defense against soil-borne pathogens. Root border cells produce an extracellular matrix of protein, polysaccharide and DNA that functions like animal neutrophil extracellular traps to immobilize pathogens. Exposing pea root border cells to the root-infecting bacterial wilt pathogen Ralstonia solanacearum triggered release of DNA-containing extracellular traps in a flagellin-dependent manner. These traps rapidly immobilized the pathogen and killed some cells, but most of the entangled bacteria eventually escaped. The R. solanacearum genome encodes two putative extracellular DNases (exDNases that are expressed during pathogenesis, suggesting that these exDNases contribute to bacterial virulence by enabling the bacterium to degrade and escape root border cell traps. We tested this hypothesis with R. solanacearum deletion mutants lacking one or both of these nucleases, named NucA and NucB. Functional studies with purified proteins revealed that NucA and NucB are non-specific endonucleases and that NucA is membrane-associated and cation-dependent. Single ΔnucA and ΔnucB mutants and the ΔnucA/B double mutant all had reduced virulence on wilt-susceptible tomato plants in a naturalistic soil-soak inoculation assay. The ΔnucA/B mutant was out-competed by the wild-type strain in planta and was less able to stunt root growth or colonize plant stems. Further, the double nuclease mutant could not escape from root border cells in vitro and was defective in attachment to pea roots. Taken together, these results demonstrate that extracellular DNases are novel virulence factors that help R. solanacearum successfully overcome plant defenses to infect plant roots and cause bacterial wilt disease.

  5. Human Adipose Tissue Derived Extracellular Matrix and Methylcellulose Hydrogels Augments and Regenerates the Paralyzed Vocal Fold.

    Directory of Open Access Journals (Sweden)

    Dong Wook Kim

    Full Text Available Vocal fold paralysis results from various etiologies and can induce voice changes, swallowing complications, and issues with aspiration. Vocal fold paralysis is typically managed using injection laryngoplasty with fat or synthetic polymers. Injection with autologous fat has shown excellent biocompatibility. However, it has several disadvantages such as unpredictable resorption rate, morbidities associated with liposuction procedure which has to be done in operating room under general anesthesia. Human adipose-derived extracellular matrix (ECM grafts have been reported to form new adipose tissue and have greater biostability than autologous fat graft. Here, we present an injectable hydrogel that is constructed from adipose tissue derived soluble extracellular matrix (sECM and methylcellulose (MC for use in vocal fold augmentation. Human sECM derived from adipose tissue was extracted using two major steps-ECM was isolated from human adipose tissue and was subsequently solubilized. Injectable sECM/MC hydrogels were prepared by blending of sECM and MC. Sustained vocal fold augmentation and symmetric vocal fold vibration were accomplished by the sECM/MC hydrogel in paralyzed vocal fold which were confirmed by laryngoscope, histology and a high-speed imaging system. There were increased number of collagen fibers and fatty granules at the injection site without significant inflammation or fibrosis. Overall, these results indicate that the sECM/MC hydrogel can enhance vocal function in paralyzed vocal folds without early resorption and has potential as a promising material for injection laryngoplasty for stable vocal fold augmentation which can overcome the shortcomings of autologous fat such as unpredictable duration and morbidity associated with the fat harvest.

  6. Human Adipose Tissue Derived Extracellular Matrix and Methylcellulose Hydrogels Augments and Regenerates the Paralyzed Vocal Fold.

    Science.gov (United States)

    Kim, Dong Wook; Kim, Eun Ji; Kim, Eun Na; Sung, Myung Whun; Kwon, Tack-Kyun; Cho, Yong Woo; Kwon, Seong Keun

    2016-01-01

    Vocal fold paralysis results from various etiologies and can induce voice changes, swallowing complications, and issues with aspiration. Vocal fold paralysis is typically managed using injection laryngoplasty with fat or synthetic polymers. Injection with autologous fat has shown excellent biocompatibility. However, it has several disadvantages such as unpredictable resorption rate, morbidities associated with liposuction procedure which has to be done in operating room under general anesthesia. Human adipose-derived extracellular matrix (ECM) grafts have been reported to form new adipose tissue and have greater biostability than autologous fat graft. Here, we present an injectable hydrogel that is constructed from adipose tissue derived soluble extracellular matrix (sECM) and methylcellulose (MC) for use in vocal fold augmentation. Human sECM derived from adipose tissue was extracted using two major steps-ECM was isolated from human adipose tissue and was subsequently solubilized. Injectable sECM/MC hydrogels were prepared by blending of sECM and MC. Sustained vocal fold augmentation and symmetric vocal fold vibration were accomplished by the sECM/MC hydrogel in paralyzed vocal fold which were confirmed by laryngoscope, histology and a high-speed imaging system. There were increased number of collagen fibers and fatty granules at the injection site without significant inflammation or fibrosis. Overall, these results indicate that the sECM/MC hydrogel can enhance vocal function in paralyzed vocal folds without early resorption and has potential as a promising material for injection laryngoplasty for stable vocal fold augmentation which can overcome the shortcomings of autologous fat such as unpredictable duration and morbidity associated with the fat harvest.

  7. Extracellular synthesis of zinc oxide nanoparticle using seaweeds of gulf of Mannar, India

    Science.gov (United States)

    2013-01-01

    Background The biosynthesis of metal nanoparticles by marine resources is thought to be clean, nontoxic, and environmentally acceptable “green procedures”. Marine ecosystems are very important for the overall health of both marine and terrestrial environments. The use of natural sources like Marine biological resources essential for nanotechnology. Seaweeds constitute one of the commercially important marine living renewable resources. Seaweeds such as green Caulerpa peltata, red Hypnea Valencia and brown Sargassum myriocystum were used for synthesis of Zinc oxide nanoparticles. Result The preliminary screening of physico-chemical parameters such as concentration of metals, concentration of seaweed extract, temperature, pH and reaction time revealed that one seaweed S. myriocystum were able to synthesize zinc oxide nanoparticles. It was confirmed through the, initial colour change of the reaction mixture and UV visible spectrophotometer. The extracellular biosynthesized clear zinc oxide nanoparticles size 36 nm through characterization technique such as DLS, AFM, SEM –EDX, TEM, XRD and FTIR. The biosynthesized ZnO nanoparticles are effective antibacterial agents against Gram-positive than the Gram-negative bacteria. Conclusion Based on the FTIR results, fucoidan water soluble pigments present in S. myriocystum leaf extract is responsible for reduction and stabilization of zinc oxide nanoparticles. by this approach are quite stable and no visible changes were observed even after 6 months. These soluble elements could have acted as both reduction and stabilizing agents preventing the aggregation of nanoparticles in solution, extracellular biological synthesis of zinc oxide nanoparticles of size 36 nm. PMID:24298944

  8. Advanced thermally stable jet fuels

    Energy Technology Data Exchange (ETDEWEB)

    Schobert, H.H.

    1999-01-31

    The Pennsylvania State University program in advanced thermally stable coal-based jet fuels has five broad objectives: (1) Development of mechanisms of degradation and solids formation; (2) Quantitative measurement of growth of sub-micrometer and micrometer-sized particles suspended in fuels during thermal stressing; (3) Characterization of carbonaceous deposits by various instrumental and microscopic methods; (4) Elucidation of the role of additives in retarding the formation of carbonaceous solids; (5) Assessment of the potential of production of high yields of cycloalkanes by direct liquefaction of coal. Future high-Mach aircraft will place severe thermal demands on jet fuels, requiring the development of novel, hybrid fuel mixtures capable of withstanding temperatures in the range of 400--500 C. In the new aircraft, jet fuel will serve as both an energy source and a heat sink for cooling the airframe, engine, and system components. The ultimate development of such advanced fuels requires a thorough understanding of the thermal decomposition behavior of jet fuels under supercritical conditions. Considering that jet fuels consist of hundreds of compounds, this task must begin with a study of the thermal degradation behavior of select model compounds under supercritical conditions. The research performed by The Pennsylvania State University was focused on five major tasks that reflect the objectives stated above: Task 1: Investigation of the Quantitative Degradation of Fuels; Task 2: Investigation of Incipient Deposition; Task 3: Characterization of Solid Gums, Sediments, and Carbonaceous Deposits; Task 4: Coal-Based Fuel Stabilization Studies; and Task 5: Exploratory Studies on the Direct Conversion of Coal to High Quality Jet Fuels. The major findings of each of these tasks are presented in this executive summary. A description of the sub-tasks performed under each of these tasks and the findings of those studies are provided in the remainder of this volume

  9. Comparative evaluation of extracellular β-D-fructofuranosidase in submerged and solid-state fermentation produced by newly identified Bacillus subtilis strain.

    Science.gov (United States)

    Lincoln, Lynette; More, Sunil S

    2018-04-17

    To screen and identify a potential extracellular β-D-fructofuranosidase or invertase producing bacterium from soil, and comparatively evaluate the enzyme biosynthesis under submerged and solid-state fermentation. Extracellular invertase producing bacteria were screened from soil. Identification of the potent bacterium was performed based on microscopic examinations and 16S rDNA molecular sequencing. Bacillus subtilis LYN12 invertase secretion was surplus with wheat bran humidified with molasses medium (70%), with elevated activity at 48 h and 37 °C under solid-state fermentation, whereas under submerged conditions increased activity was observed at 24 h and 45 °C in the molasses medium. The study revealed a simple fermentative medium for elevated production of extracellular invertase from a fast growing Bacillus strain. Bacterial invertases are scarce and limited reports are available. By far, this is the first report on the comparative analysis of optimization of extracellular invertase synthesis from Bacillus subtilis strain by submerged and solid-state fermentation. The use of agricultural residues increased yields resulting in development of a cost-effective and stable approach. Bacillus subtilis LYN12 invertase possesses excellent fermenting capability to utilize agro-industrial residues under submerged and solid-state conditions. This could be a beneficial candidate in food and beverage processing industries. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

  10. Population Games, Stable Games, and Passivity

    Directory of Open Access Journals (Sweden)

    Michael J. Fox

    2013-10-01

    Full Text Available The class of “stable games”, introduced by Hofbauer and Sandholm in 2009, has the attractive property of admitting global convergence to equilibria under many evolutionary dynamics. We show that stable games can be identified as a special case of the feedback-system-theoretic notion of a “passive” dynamical system. Motivated by this observation, we develop a notion of passivity for evolutionary dynamics that complements the definition of the class of stable games. Since interconnections of passive dynamical systems exhibit stable behavior, we can make conclusions about passive evolutionary dynamics coupled with stable games. We show how established evolutionary dynamics qualify as passive dynamical systems. Moreover, we exploit the flexibility of the definition of passive dynamical systems to analyze generalizations of stable games and evolutionary dynamics that include forecasting heuristics as well as certain games with memory.

  11. Applying extracellular vesicles based therapeutics in clinical trials - an ISEV position paper

    NARCIS (Netherlands)

    Lener, Thomas; Gimona, Mario; Aigner, Ludwig; Börger, Verena; Buzas, Edit; Camussi, Giovanni; Chaput, Nathalie; Chatterjee, Devasis; Court, Felipe A; Del Portillo, Hernando A; O'Driscoll, Lorraine; Fais, Stefano; Falcon-Perez, Juan M; Felderhoff-Mueser, Ursula; Fraile, Lorenzo; Gho, Yong Song; Görgens, André; Gupta, Ramesh C; Hendrix, An; Hermann, Dirk M; Hill, Andrew F; Hochberg, Fred; Horn, Peter A; de Kleijn, Dominique; Kordelas, Lambros; Kramer, Boris W; Krämer-Albers, Eva-Maria; Laner-Plamberger, Sandra; Laitinen, Saara; Leonardi, Tommaso; Lorenowicz, Magdalena J; Lim, Sai Kiang; Lötvall, Jan; Maguire, Casey A; Marcilla, Antonio; Nazarenko, Irina; Ochiya, Takahiro; Patel, Tushar; Pedersen, Shona; Pocsfalvi, Gabriella; Pluchino, Stefano; Quesenberry, Peter; Reischl, Ilona G; Rivera, Francisco J; Sanzenbacher, Ralf; Schallmoser, Katharina; Slaper-Cortenbach, Ineke; Strunk, Dirk; Tonn, Torsten; Vader, Pieter; van Balkom, Bas W M; Wauben, Marca|info:eu-repo/dai/nl/112675735; Andaloussi, Samir El; Théry, Clotilde; Rohde, Eva; Giebel, Bernd

    2015-01-01

    Extracellular vesicles (EVs), such as exosomes and microvesicles, are released by different cell types and participate in physiological and pathophysiological processes. EVs mediate intercellular communication as cell-derived extracellular signalling organelles that transmit specific information

  12. Extracellular Polymeric Substances Govern the Surface Charge of Biogenic Elemental Selenium Nanoparticles

    KAUST Repository

    Jain, Rohan; Jordan, Norbert; Weiss, Stephan; Foerstendorf, Harald; Heim, Karsten; Kacker, Rohit; Hü bner, René ; Kramer, Herman; van Hullebusch, Eric D.; Farges, Franç ois; Lens, Piet N. L.

    2015-01-01

    investigated the presence of extracellular polymeric substances (EPS) on BioSeNPs. The role of EPS in capping the extracellularly available BioSeNPs was also examined. Fourier transform infrared (FT-IR) spectroscopy and colorimetric measurements confirmed

  13. Concise review : Developing best-practice models for the therapeutic use of extracellular vesicles

    NARCIS (Netherlands)

    Reiner, Agnes T.; Witwer, Kenneth W.; Van Balkom, Bas W.M.; De Beer, Joel; Brodie, Chaya; Corteling, Randolph L.; Gabrielsson, Susanne; Gimona, Mario; Ibrahim, Ahmed G.; De Kleijn, Dominique; Lai, Charles P.; Tvall, Jan Lo; Del Portillo, Hernando A; Reischl, Ilona G; Riazifar, Milad; Salomon, Carlos; Tahara, Hidetoshi; Toh, Wei Seong; Wauben, Marca H M; Yang, Vicky K.; Yang, Yijun; Yeo, Ronne Wee Yeh; Yin, Hang; Giebel, Bernd; Rohde, Eva; Lim, Sai Kiang

    2017-01-01

    Growing interest in extracellular vesicles (EVs, including exosomes and microvesicles) as therapeutic entities, particularly in stem cell-related approaches, has underlined the need for standardization and coordination of development efforts. Members of the International Society for Extracellular

  14. Fabrication of highly modulable fibrous 3D extracellular microenvironments

    KAUST Repository

    Zhang, Xixiang; Han, Fangfei; Syed, Ahad; Bukhari, Ebtihaj M.; Siang, Basil Chew Joo; Yang, Shan; Zhou, Bingpu; Wen, Wei-jia; Jiang, Dechen

    2017-01-01

    Three-dimensional (3D) in vitro scaffolds that mimic the irregular fibrous structures of in vivo extracellular matrix (ECM) are critical for many important biological applications. However, structural properties modulation of fibrous 3D scaffolds remains a challenge. Here, we report the first highly modulable 3D fibrous scaffolds self-assembled by high-aspect-ratio (HAR) microfibers. The scaffolds structural properties can be easily tailored to incorporate various physical cues, including geometry, stiffness, heterogeneity and nanotopography. Moreover, the fibrous scaffolds are readily and accurately patterned on desired locations of the substrate. Cell culture exhibits that our scaffolds can elicit strong bidirectional cell-material interactions. Furthermore, a functional disparity between the two-dimensional substrate and our 3D scaffolds is identified by cell spreading and proliferation data. These results prove the potential of the proposed scaffold as a biomimetic extracellular microenvironment for cell study.

  15. Microscopic monitoring of extracellular pH in dental biofilms

    DEFF Research Database (Denmark)

    Schlafer, Sebastian; Garcia, Javier; Greve, Matilde

    pH in dental biofilm is a key virulence factor for the development of caries lesions. The complex three-dimensional architecture of dental biofilms leads to steep gradients of nutrients and metabolites, including organic acids, across the biofilm. For decades, measuring pH in dental biofilm has...... been limited to monitoring bulk pH with electrodes. Although pH microelectrodes with a better spatial resolution have been developed, they do not permit to monitor horizontal pH gradients in real-time. Quantitative fluorescent microscopic techniques, such as fluorescence lifetime imaging or pH...... ratiometry, can be employed to map the pH landscape in dental biofilm with more detail. However, when pH sensitive fluorescent probes are used to visualize pH in biofilms, it is crucial to differentiate between extracellular and intracellular pH. Intracellular microbial pH and pH in the extracellular matrix...

  16. Specialisation of extracellular matrix for function in tendons and ligaments

    Science.gov (United States)

    Birch, Helen L.; Thorpe, Chavaunne T.; Rumian, Adam P.

    2013-01-01

    Summary Tendons and ligaments are similar structures in terms of their composition, organisation and mechanical properties. The distinction between them stems from their anatomical location; tendons form a link between muscle and bone while ligaments link bones to bones. A range of overlapping functions can be assigned to tendon and ligaments and each structure has specific mechanical properties which appear to be suited for particular in vivo function. The extracellular matrix in tendon and ligament varies in accordance with function, providing appropriate mechanical properties. The most useful framework in which to consider extracellular matrix differences therefore is that of function rather than anatomical location. In this review we discuss what is known about the relationship between functional requirements, structural properties from molecular to gross level, cellular gene expression and matrix turnover. The relevance of this information is considered by reviewing clinical aspects of tendon and ligament repair and reconstructive procedures. PMID:23885341

  17. Neutrophil extracellular traps: double-edged swords of innate immunity.

    Science.gov (United States)

    Kaplan, Mariana J; Radic, Marko

    2012-09-15

    Spectacular images of neutrophils ejecting nuclear chromatin and bactericidal proteins, in response to microbes, were first reported in 2004. As externalized chromatin could entangle bacteria, these structures were named neutrophil extracellular traps (NETs). Subsequent studies identified microorganisms and sterile conditions that stimulate NETs, as well as additional cell types that release extracellular chromatin. The release of NETs is the most dramatic stage in a cell death process called NETosis. Experimental evidence suggests that NETs participate in pathogenesis of autoimmune and inflammatory disorders, with proposed involvement in glomerulonephritis, chronic lung disease, sepsis, and vascular disorders. Exaggerated NETosis or diminished NET clearance likely increases risk of autoreactivity to NET components. The biological significance of NETs is just beginning to be explored. A more complete integration of NETosis within immunology and pathophysiology will require better understanding of NET properties associated with specific disease states and microbial infections. This may lead to the identification of important therapeutic targets.

  18. Extracellular DNA Shields against Aminoglycosides in Pseudomonas aeruginosa Biofilms

    DEFF Research Database (Denmark)

    Chiang, Wen-Chi; Nilsson, Martin; Jensen, Peter Østrup

    2013-01-01

    Within recent years, it has been established that extracellular DNA is a key constituent of the matrix of microbial biofilms. In addition, it has recently been demonstrated that DNA binds positively charged antimicrobials such as aminoglycosides and antimicrobial peptides. In the present study, we...... provide evidence that extracellular DNA shields against aminoglycosides in Pseudomonas aeruginosa biofilms. We show that exogenously supplemented DNA integrates into P. aeruginosa biofilms and increases their tolerance toward aminoglycosides. We provide evidence that biofilms formed by a DNA release......-deficient P. aeruginosa quorum-sensing mutant are more susceptible to aminoglycoside treatment than wild-type biofilms but become rescued from the detrimental action of aminoglycosides upon supplementation with exogenous DNA. Furthermore, we demonstrate that exposure to lysed polymorphonuclear leukocytes...

  19. The Role of Extracellular Vesicles in Bone Metastasis

    Directory of Open Access Journals (Sweden)

    Michela Rossi

    2018-04-01

    Full Text Available Multiple types of cancer have the specific ability to home to the bone microenvironment and cause metastatic lesions. Despite being the focus of intense investigation, the molecular and cellular mechanisms that regulate the metastasis of disseminated tumor cells still remain largely unknown. Bone metastases severely impact quality of life since they are associated with pain, fractures, and bone marrow aplasia. In this review, we will summarize the recent discoveries on the role of extracellular vesicles (EV in the regulation of bone remodeling activity and bone metastasis occurrence. Indeed, it was shown that extracellular vesicles, including exosomes and microvesicles, released from tumor cells can modify the bone microenvironment, allowing the formation of osteolytic, osteosclerotic, and mixed mestastases. In turn, bone-derived EV can stimulate the proliferation of tumor cells. The inhibition of EV-mediated crosstalk between cancer and bone cells could represent a new therapeutic target for bone metastasis.

  20. Sea Ice Microorganisms: Environmental Constraints and Extracellular Responses

    Directory of Open Access Journals (Sweden)

    Jody W. Deming

    2013-03-01

    Full Text Available Inherent to sea ice, like other high latitude environments, is the strong seasonality driven by changes in insolation throughout the year. Sea-ice organisms are exposed to shifting, sometimes limiting, conditions of temperature and salinity. An array of adaptations to survive these and other challenges has been acquired by those organisms that inhabit the ice. One key adaptive response is the production of extracellular polymeric substances (EPS, which play multiple roles in the entrapment, retention and survival of microorganisms in sea ice. In this concept paper we consider two main areas of sea-ice microbiology: the physico-chemical properties that define sea ice as a microbial habitat, imparting particular advantages and limits; and extracellular responses elicited in microbial inhabitants as they exploit or survive these conditions. Emphasis is placed on protective strategies used in the face of fluctuating and extreme environmental conditions in sea ice. Gaps in knowledge and testable hypotheses are identified for future research.