Dissertations / Theses on the topic 'Xanthophylls'
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Davies, Bethan Wyn. "Xanthophylls as metabolic precursors." Thesis, Aberystwyth University, 1986. http://hdl.handle.net/2160/92d4cd09-9ea7-4e80-9af4-a3aecccd778b.
Full textEtienne-Leveille, Valerie. "Three studies of natural xanthophylls." FIU Digital Commons, 2003. http://digitalcommons.fiu.edu/etd/3282.
Full textPhillip, Denise Mary. "Xanthophylls in light-harvesting complexes of higher plants." Thesis, Liverpool John Moores University, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.242313.
Full text史賢明 and Xianming Shi. "High yield production of lutein by Chlorella protothecoides under heterotrophic conditions of growth." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1998. http://hub.hku.hk/bib/B31237666.
Full textShi, Xianming. "High yield production of lutein by Chlorella protothecoides under heterotrophic conditions of growth /." Hong Kong : University of Hong Kong, 1998. http://sunzi.lib.hku.hk/hkuto/record.jsp?B19859880.
Full textLi, Tao. "Characterization of lutein biosynthesis in green alga chlorella pyrenoidosa under heterotrophic condition." HKBU Institutional Repository, 2012. https://repository.hkbu.edu.hk/etd_ra/1399.
Full textKim, Joonyul. "Functional and evolutionary characterization of Arabidopsis carotenoid hydroxylases." Diss., Connect to online resource - MSU authorized users, 2008.
Find full textTitle from PDF t.p. (viewed on Mar. 30, 2009) Includes bibliographical references (p. 127-139). Also issued in print.
Schlatterer, Jörg [Verfasser]. "Analysis of Xanthophylls in Food and their Behaviour during Human Digestion / Jörg Schlatterer." Aachen : Shaker, 2007. http://d-nb.info/1163609641/34.
Full textDerenick, Rhianna A. "The role of lutein and zeaxanthin in protecting the retina from light damage /." Connect to this title online, 2007. http://hdl.handle.net/1957/3823.
Full textTerry, Christian James. "Gene expression and ABA biosynthesis in water stressed plants." Thesis, University of Nottingham, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.308310.
Full textChitchumroonchokchai, Chureeporn. "Lutein and zeaxanthin use of in vitro models to examine digestive stability, absorption, and photoprotective activity in human lens epithelial cells /." Connect to this title online, 2004. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1095778573.
Full textTitle from first page of PDF file. Document formatted into pages; contains xiii, 179 p.; also includes graphics (some col.). Includes bibliographical references (p. 147-179).
Griffith, Gary P., and n/a. "The photoprotective xanthophyll cycle in Southern Ocean phytoplankton and Antarctic sea-ice algae." University of Otago. Department of Marine Science, 2008. http://adt.otago.ac.nz./public/adt-NZDU20080704.111758.
Full textWoo, Tak-yunn Tiffany, and 胡德欣. "Neuroprotective strategies in a rat model of retinal detachment." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2012. http://hub.hku.hk/bib/B48334911.
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Medicine
Master
Master of Research in Medicine
Sandeski, Lígia Mara [UNESP]. "Otimização da pigmentação da gema do ovo: Lígia Mara Sandeski. -." Universidade Estadual Paulista (UNESP), 2013. http://hdl.handle.net/11449/94680.
Full textCoordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
The color of the egg yolk depends on the absorption and the deposition of carotenoids present in the hens´ diets and represents a sensory characteristic of great impact on the product acceptance. Corn is commonly used as energy value ingredient for hens´ diets formulations. Moreover, due to its additional pigmentation properties, it might be used to color egg yolk. The purpose of this research was to optimize the proportions between yellow and red pigments in hens´ corn based rations to provide color maximization for yolks. Sixty Dekalbe laying hens were separately distributed in cages inside a rearing barn to receive the experimental diets for 21 days at a daily feeding of 110 g and water ad libitum. Fifteen treatments were defined by means of a central composite rotatable design in which the variables were the yellow pigments from the diets (corn + gluten meal), the yellow supplementary pigments (lutein + zeaxanthin) and the red supplementary pigments (cantaxanthin), each of them at three different concentrations. Hens´ weights were recorded at the beginning and at the end of the experiment and the eggs weights were recorded daily. Yolks colors were determined by means of objective (L, a, b) and subjective (color fan) measurements. Global acceptance of yolks color was investigated with a five points hedonic scale. The results were analyzed by ANOVA, means comparison tests (t test and Dunn test) and regression analysis by Response Surface Methodology, at 5% significance level. Hens` final weights and eggs weights were not influenced by the treatments. Seven distinct colors for yolks were identified with the color fan. The most preferred yolks scored 9 and derived from the treatment which provided the highest yellow pigments concentrations (2.0 mg/hen/day) and no red pigments while the most rejected yolks scored 14 and derived from treatments which provided the highest concentration of red pigment (0.7 mg/hen/day), besides the yellow...
Sandeski, Lígia Mara. "Otimização da pigmentação da gema do ovo / Lígia Mara Sandeski. -." Araçatuba, 2013. http://hdl.handle.net/11449/94680.
Full textBanca: Cecilio Viega Soares Filho
Banca: Otto Mack Junqueira
Resumo: A coloração da gema é dependente da absorção e da deposição dos carotenoides presentes na dieta da ave e representa uma característica sensorial de grande influência sobre a aceitabilidade do produto. O milho, ingrediente energético bastante utilizado na composição de ração de galinhas poedeiras, também apresenta potencial pigmentante, que deve ser explorado quando o objetivo é fornecer pigmentação à gema. Este trabalho teve como objetivo determinar as proporções entre pigmentos amarelos e vermelhos em rações contendo milho como principal fator energético para galinhas poedeiras visando promover a maximização da coloração de gema. Sessenta galinhas poedeiras da linhagem Dekalbe em fase de postura foram alocadas individualmente em gaiolas em galpão apropriado, onde receberam as rações experimentais durante 21 dias, com arraçoamento diário de 110 g e água à vontade. Foram aplicados 15 tratamentos, definidos por um delineamento composto central rotacional em que as variáveis estudadas foram os pigmentos amarelos provenientes dos ingredientes da ração (milho + farelo de gluten de milho), os pigmentos amarelos suplementares (luteína + zeaxantina) e os pigmentos vermelhos suplementares (cantaxantina), cada uma com três concentrações distintas. As aves foram pesadas no início e ao final do experimento e o peso dos ovos foi registrado diariamente. A cor das gemas foi determinada pelos métodos objetivo (L, a, b) e subjetivo (leque colorimétrico). A aceitação global das gemas foi determinada por meio de escala hedônica de cinco pontos. Os resultados obtidos foram submetidos a análises de variâncias, testes de comparação de médias (teste t e teste de Dunn) e à análise de regressão pela metodologia de superfície de resposta, adotando-se o nível de significância de 5%. O peso final das aves e o peso dos ovos não foram influenciados pelos diferentes... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: The color of the egg yolk depends on the absorption and the deposition of carotenoids present in the hens' diets and represents a sensory characteristic of great impact on the product acceptance. Corn is commonly used as energy value ingredient for hens' diets formulations. Moreover, due to its additional pigmentation properties, it might be used to color egg yolk. The purpose of this research was to optimize the proportions between yellow and red pigments in hens' corn based rations to provide color maximization for yolks. Sixty Dekalbe laying hens were separately distributed in cages inside a rearing barn to receive the experimental diets for 21 days at a daily feeding of 110 g and water ad libitum. Fifteen treatments were defined by means of a central composite rotatable design in which the variables were the yellow pigments from the diets (corn + gluten meal), the yellow supplementary pigments (lutein + zeaxanthin) and the red supplementary pigments (cantaxanthin), each of them at three different concentrations. Hens' weights were recorded at the beginning and at the end of the experiment and the eggs weights were recorded daily. Yolks colors were determined by means of objective (L, a, b) and subjective (color fan) measurements. Global acceptance of yolks color was investigated with a five points hedonic scale. The results were analyzed by ANOVA, means comparison tests (t test and Dunn test) and regression analysis by Response Surface Methodology, at 5% significance level. Hens' final weights and eggs weights were not influenced by the treatments. Seven distinct colors for yolks were identified with the color fan. The most preferred yolks scored 9 and derived from the treatment which provided the highest yellow pigments concentrations (2.0 mg/hen/day) and no red pigments while the most rejected yolks scored 14 and derived from treatments which provided the highest concentration of red pigment (0.7 mg/hen/day), besides the yellow...
Mestre
Brackenridge, Anika Elma. "Over-expression and analysis of two Vitis vinifera carotenoid biosynthetic genes in transgenic Arabidopsis." Thesis, Stellenbosch : University of Stellenbosch, 2006. http://hdl.handle.net/10019/508.
Full textBabino, Darwin O. "High-performance liquid chromatography measurement of carotenoids in human serum, etoposide in pig cerebrospinal fluid and measurement of the aggregation of xanthophylls in aqueous solutions." FIU Digital Commons, 2010. http://digitalcommons.fiu.edu/etd/1360.
Full textMubaiwa, Byron Tawanda. "The quantification of fucoxanthin from selected South African marine brown algae (Phaeophyta) using HPLC-UV/Vis." Thesis, Rhodes University, 2015. http://hdl.handle.net/10962/d1017879.
Full textGiossi, Chiara. "Photoacclimation and photoprotection strategies in siphonous green algae of the order Bryopsidales (Codium tomentosum and Bryopsis plumosa)." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2020. http://amslaurea.unibo.it/19835/.
Full textGarcia, Mendoza Ernesto. "Photoadaptation in microalgae: xanthophyll cycle and state transitions strategies." [S.l. : Amsterdam : s.n.] ; Universiteit van Amsterdam [Host], 2000. http://dare.uva.nl/document/56679.
Full textThomas, Sara E. "Mechanisms of Xanthophyll Uptake in Retinal Pigment Epithelial Cells." The Ohio State University, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=osu1478183410555123.
Full textJohnson, Matthew Paul. "Role of the xanthophyll cycle in photoprotection in Arabidopsis thaliana." Thesis, University of Sheffield, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.485881.
Full textWeller, Philipp [Verfasser]. "Xanthophyll Esters: Occurrence and Comparative Studies on their Bioavailability / Philipp Weller." Aachen : Shaker, 2005. http://d-nb.info/1181616166/34.
Full textSavill, Julia. "Carotenoid biosynthesis in higher plants." Thesis, Liverpool John Moores University, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.313103.
Full textSavy, Stephanie. "Biosynthèse de caroténoïdes aromatiques hydroxyléspar des bactéries non photosynthétiques :Des carotènes aux xanthophylles." Phd thesis, Université de Bretagne occidentale - Brest, 2005. http://tel.archives-ouvertes.fr/tel-00193188.
Full textDans un premier temps, les pigments produits par ces bactéries sont étudiés par HPLC et LCMS. Ces études ont montré que B. linens et S. mediolani synthétisent majoritairement du 3,3'-di-hydroxy-isoréniératène. Elles ont également révélé l'absence de ce composé chez M. aurum. Contrairement à ce qui est décrit dans la littérature cette bactérie accumule un caroténoïde de masse moléculaire supérieure à celle du di-hydroxy-isoréniératène. Une purification a été entreprise pour une analyse en RMN mais les faibles quantités obtenues n'ont pas permis la détermination de la structure.
Dans un second temps, la réaction d'hydroxylation, dernière étape dans la biosynthèse de ces caroténoïdes a été étudiée. On cherche à identifier le type d'enzyme et le substrat de cette étape. L'utilisation d'inhibiteurs spécifiques de cytochrome P450 dans les cultures bactériennes se traduit par l'accumulation d'isoréniératène et la disparition des formes hydroxylées chez B. linens et S. mediolani. Ces résultats montrent l'implication d'un cytochrome P450 dans l'hydroxylation de l'isoréniératène pour ces bactéries.
Le cluster de la caroténogénèse a été récemment séquencé et identifié chez les trois bactéries étudiées. Seul le cluster de B. linens comporte un gène (orf 10) pouvant coder une hydroxylase qui présente un motif caractéristique d'un cytochrome P450, cependant son implication dans l'hydroxylation des caroténoïdes aromatiques n'est pas précisée.
Une série de mutagénèse aléatoire par rayonnement U.V. a été entreprise sur B. linens. Elle a permis d'obtenir un mutant noté BLMJ. Les analyses HPLC et LCMS des pigments produits par BLMJ montrent qu'il accumule très majoritairement de l'isoréniératène. Le système responsable de l'hydroxylation de l'isoréniératène de BLMJ apparaît défectueux. L'analyse de la séquence de l'ORF 10 de BLMJ révèle la présence d'une mutation au niveau de l'acide aminé 84 où la phénylalanine est remplacée par une sérine. Après comparaison avec des structures 3D de P450 connus il semblerait que cet acide aminé soit important dans la stabilisation du groupement prosthétique de l'enzyme. Sa mutation entraînerait donc une perte d'activité de l'enzyme.
Pour s'assurer de l'implication de l'ORF 10 dans l'hydroxylation de l'isoréniératène chez B. linens, nous avons électroporé B. linens avec l'orf 10 muté de BLMJ. Un mutant (noté BLE7J) accumulant majoritairement de l'isoréniératène a pu être isolé. L'analyse de la séquence de l'ORF 10 de BLE7J révèle la présence d'une mutation au niveau de l'acide aminé 267 où l'acide glutamique est remplacé par une glutamine. Après comparaison de séquences, il apparaît que cet acide aminé appartient à un motif conservé dans les séquences de P450 car impliqué dans la stabilisation du groupement prosthétique de l'enzyme. Sa mutation entraînerait donc une perte d'activité de l'enzyme.
Les mutants BLMJ et BLE7J montrent que le P450 responsable de l'hydroxylation de l'isoréniératène en 3,3'-di-hydoxy-isoréniératène est codé par l'orf 10 du cluster crt de B. linens.
Tardy, Florence. "Localisation et fonctions du cycle des xanthophylles dans les chloroplastes des plantes supérieures." Lyon 1, 1997. http://www.theses.fr/1997LYO10281.
Full textWentworth, Mark. "Quenching of chlorophyll fluorescence in plant light-harvesting complexes." Thesis, University of Sheffield, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.340168.
Full textMorin-Savy, Stéphanie. "Biosynthèse de caroténoi͏̈des aromatiques hydroxylés par des bactéries non photosynthétiques : Des carotènes aux xanthophylles." Brest, 2005. http://www.theses.fr/2005BRES2002.
Full textThis research work aims at studying the hydroxylation step interfering in the biosynthesis of aromatic carotenoids in some non-photosynthetic bacteria: Brevibacterium linens, Streptomyces mediolani and Mycobacterium aurum. HPLC and LCMS analyses of the pigments produced show that only B. Linens and S. Mediolani synthetize di-hydroxy-isorenieratene. With the use of specific enzymatic inhibitors, we have come to the conclusion that for B. Linens as well as for S. Mediolani, the isorenieratene seems to be hydroxylated by a P450 cytochrome. Two mutants in hydroxylation step were obtained after random then supervised mutagenesis experiments on B. Linens. Mutants have a mutation on the orf 10 in crt cluster. After sequence analysis of mutants proteins, it seems orf 10 in crt cluster of B. Linens encodes the cytochrome P450 involved in hydroxylation of isorenieratene into di-hydroxy-isorenieratene
Scherrers, Roger. "Carotinoide und Sauerstoff antioxidative Eigenschaften von aromatischen und nicht aromatischen Xanthophyllen /." [S.l.] : [s.n.], 2006. http://deposit.ddb.de/cgi-bin/dokserv?idn=982670982.
Full textPieters, Alejandro J. "Photosynthetic carbon and energy balance in tobacco : relation to phosphoribulokinase and phosphate." Thesis, University of Nottingham, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.312233.
Full textZamboni, Alessandro <1978>. "Role of xanthophyll and water-water cycles in the protection of photosynthetic apparatus in Arbutus unedo and Arabidopsis thaliana." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2007. http://amsdottorato.unibo.it/518/.
Full textAlvarez-Calderon, Francesca. "Calculations on the end-group conformational barrier in carotenoids and a study of the bioavailability of xanthophyll esters in humans." FIU Digital Commons, 2007. http://digitalcommons.fiu.edu/etd/1272.
Full textZhao, Liang. "Effects of altered levels of expression of β-carotene hydroxylase on xanthophyll cycle pool size and stress tolerance of rice (Oryza sativa L.)." Thesis, University of Nottingham, 2016. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.718983.
Full textDujardyn, Marie-Christine. "Régulation de la photosynthèse de l'orge sous fort éclairement : photoinhibition et reprise." Paris 11, 1989. http://www.theses.fr/1989PA112264.
Full textExposure of low-light-grown barley plants to high irradiance resulted in the loss of photosynthetic capacity called photo inhibition. This was characterized by a decrease in the quantum yield for CO assimilation and the loss of variable fluorescence at 690 nm. Photinhibition resulted in a partial (but reversable) decline in photosynthetic efficiency and capacity. The principal factor responsible for the inhibition of Benson-Calvin cycle activity was the resultant deficit in provision of reducing power. This is evidenced by the failure to maintain PGA reduction (and as a consequence RuBP regeneration) and also by the decrease in the activities of redox-modulated enzymes
Lavaud, Johann. "Stratégies d'adaptation des diatomées phytoplanctoniques aux variations de l'intensité lumineuse rencontrées dans leur environnement naturel." Paris 6, 2002. http://www.theses.fr/2002PA066212.
Full textDamaraju, Sridevi. "Analysis of proteins involved in chlorophyll catabolism." Doctoral thesis, Humboldt-Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät I, 2011. http://dx.doi.org/10.18452/16322.
Full textChlorophyll (Chl) catabolism is characteristically seen during leaf senescence, fruit ripening and seed maturation. Disruption of this coordinated process under frost conditions delays Chl breakdown and is a great concern in rapeseed oil production. The present work addresses this problem by studying the effect of enhanced Chl catabolism in genetically modified tobacco plants. Chl is catabolised to colourless catabolites through a series of enzymatic reactions initiated by Chlorophyllase (Chlase). A water soluble chlorophyll protein (WSCP) has been proposed to transport Chl from thylakoid membranes to the site of action of Chlase. It was assumed that enhancing the gene expression of these early events in Chl catabolism would increase the Chl breakdown process. The present work analysed the overexpression of Chlase from Citrus clementii (CcCHLASE) and WSCP gene from cauliflower (Cau-WSCP) in modified tobacco plants. Initially, the cDNA sequence of CcCHLASE was expressed in E. coli and in vitro tests confirmed the hydrolytic activity of Chlase on Chl. Subsequently, tobacco plants overexpressing CcCHLASE were generated and three T1 lines were analysed at various stress and senescence conditions. The in vivo production of Chlorophyllide (Chlide) indicated the extent of increased Chl breakdown. The Chlase overexpressor lines showed higher Chlide a steady state levels under all tested conditions in comparison to the WT tobacco plants. However, the end catabolites did not show much difference from WT plants. On the other hand, WSCP overexpressor lines did not show any increase in Chlide a levels, but demonstrated an increased protochlorophyllide (Pchlide) levels. This suggested the role of WSCP as a storage molecule of Chl precursors. Additionally, photoprotective function of WSCP was confirmed in WSCP overexpressors, by lower zeaxanthin levels and peroxidase activity even at high light intensities of 700 – 900 µmol photons m-2 s-1 in comparison to the WT tobacco plants.
Stella, Giulio Rocco. "Light stress and photoprotection in green algae, mosses and diatoms." Thesis, Paris 6, 2016. http://www.theses.fr/2016PA066430/document.
Full textThe molecular bases of responses to light excess in photosynthetic organisms having different evolutionary histories and belonging to different lineages are still not completely characterized. Therefore I explored the functions of photoprotective antennae in green algae, mosses and diatoms, together with the role of the two xanthophyll cycles present in diatoms.I studied the Light Harvesting Complex Stress-Related (LHCSR) proteins in different organisms. In the green alga Chlamydomonas reinhardtii, LHCSR3 is a protein important for photoprotection. I used site-specific mutagenesis in vivo and in vitro and identified three residues of LHCSR3 that are responsible for its activation.With the moss Physcomitrella patens I studied the in vitro spectroscopic and quenching characteristics of different pigment-binding mutants of the protein LHCSR1, focusing in particular on chlorophylls A2 and A5.LHCSRs in diatoms are named LHCXs, and in Phaeodactylum tricornutum I found that multiple abiotic stress signals converge to regulate the LHCX content of cells, providing a way to fine-tune light harvesting and photoprotection.The other main driver of photoprotection in diatoms is the xanthophyll cycle. Here I found that the accumulation of viola- and zeaxanthin in P. tricornutum have a negative effect in the development of NPQ, showing that zeaxanthin does not participate in the enhancing of NPQ in diatoms.Thanks to these studies done on different organisms, we gained a deeper knowledge on the shared characteristics and on the peculiar features about photoprotection in green algae, mosses and diatoms
LINS, NETO João da Rocha. "Potencial antioxidante de plantas da flora pernambucana." Universidade Federal de Pernambuco, 2015. https://repositorio.ufpe.br/handle/123456789/16900.
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CAPEs
O Brasil é considerado o país com a maior biodiversidade do mundo, nele as formações vegetais do Bioma Caatinga e Mata Atlântica representam fontes potenciais para a prospecção de biomoléculas de interesse científico. Entre essas biomoléculas encontram-se aquelas com atividade antioxidante, substâncias que são capazes de neutralizar ou reparar a ação dos radicais livres e dessa forma combatendo o estresse oxidativo. Vários antioxidantes sintéticos estão presentes no mercado, porém estudos vêm demonstrando a possibilidade de efeitos tóxicos desses produtos sintéticos, fato que gerou estímulo para a busca de antioxidantes naturais. O presente trabalho visou investigar a atividade antioxidante de extratos de folhas de 5 espécies vegetais encontradas no Bioma Caatinga e Mata Atlântica, a saber: Abarema cochliacarpos (AC), Croton nummularius (CN), Myroxylon Peruiferum (MP), Stryphnodendron pulcherrimum (SP) e Tanaecium xanthophyllum (TX) por 3 metodologias in vitru: ensaio do DPPH, ABTS e fosfomolibdênio (capacidade antioxidante total - CAT). Adicionalmente foi realizada uma investigação fitoquímica dos extratos por cromatografia em camada delgada (CCD) bem como dosagem do teor de fenóis e flavonoides totais com o intuito de apontar os possíveis compostos ativos responsáveis por tal atividade. A análise do perfil fitoquímico evidenciou a presença de saponinas, fenilpropanoides e flavonoides em todas os extratos, enquanto que terpenoides e proantocianidinas foram encontrados em AC, alcaloides em CN, cumarinas em MP, proantocianidinas e mono-sesquiterpenoides em SP. As dosagens de fenóis e flavonóides totais dos extratos variaram de 28,84 a 120,39 (mg EAG. g-1 extrato) e 3,84 a 10,52 (mg EQ. g-1 extrato), respectivamente. Os valores de CI50 da atividade sequestradora de radicais DPPH variaram de 31,62 a 87,84 μg/mL. A porcentagem de sequestro de radicais ABTS variou de 20,92 a 75,69 % e a porcentagem da capacidade antioxidante total (%CAT) de 15,13 a 43,71 %. Foi evidenciado também uma correlação positiva entre o conteúdo de fenóis totais e atividade antioxidante pelos ensaios do radical ABTS (ρ = 0,926; R2 = 0,858) e CAT (ρ = 0,933; R2 = 0,872), o que indica o papel chave dos compostos fenólicos na atividade antioxidante dos extratos estudados. Mais estudos são requeridos no sentido de se isolar esses compostos para melhor caracterizá-los, assim como a realização de testes de atividade antioxidante in vivo.
Brazil is considered the most biodiverse country in the world. Its vegetation areas from the Caatinga and Atlantic forest biomes represent potential sources for scanning biomolecules of scientific interest. Among these biomolecules are those endowed with antioxidant activity, substances capable to neutralize or repair the action of free radicals and thus fighting against oxidative stress. Several synthetic antioxidants are out there in the market, but studies have shown the possible toxic effects of these synthetic products, which became a stimulus for the search of natural antioxidants. This study aims to investigate the antioxidant activity of leaf extracts from 5 plant species found in the Caatinga and Atlantic forest biomes, namely: Abarema cochliacarpos (AC), Croton nummularius (CN), Myroxylon Peruiferum (MP), Stryphnodendron pulcherrimum (SP) e Tanaecium xanthophyllum (TX) by 3 in vitru methodologies: DPPH, ABTS radical scavenging activities and phosphomolybdenum method (total antioxidant capacity – TAC). Additionally a phytochemical screening of the extracts by thin layer chromatography (TLC) was conducted as well as measurement of total phenolic and flavonoid content in order to point out the possible active compounds responsible for such activity. The phytochemical screening analysis revealed the presence of saponins, flavonoids and phenylpropanoids in all plant extracts. However, terpenoids and proanthocyanidins were found in CA, alkaloids in CN, coumarins in MP, proanthocyanidins and mono-sesquiterpenoids in SP. Total phenolic and flavonoid content of the extracts ranged from 28.84 to 120.39 (mg GAE. g-1 extract) and 3.84 to 10.52 (QE mg. g-1 extract), respectively. The IC50 values of DPPH radical scavenging activity ranged from 31.62 to 87.84 μg/mL. The percentage ABTS radical scavenging activity ranged from 20.92 to 75.69 % and the percentage total antioxidant capacity (%TAC) ranged from 15.13 to 43.71 %. It was also demonstrated a positive correlation between total phenolic content and ABTS radical scavenging activity (ρ = 0.926, R2 = 0.858) and TAC (ρ = 0.933, R2 = 0.872), which denotes the key role of phenolic compounds in the antioxidant activity of the extracts studied. Further studies are required in order to isolate these compounds to characterize them better as well as assessment of their antioxidant activity in vivo.
Damerval, Marc. "Identification et rôle physiologique des inclusions contenues dans le système nerveux central de la moule Mytilus edulis et de la crépidule Crepidula fornicata." Caen, 1985. http://www.theses.fr/1985CAEN2004.
Full textDagenais, Guillaume. "Effet des pigments xanthophylles jaunes du gluten de maïs et utilisation de différents niveaux de lysine dans la moulée d'élevage; impacts sur les performances et la coloration de la truite arc-en-ciel (Onchorynchus mykiss)." Thesis, Université Laval, 2008. http://www.theses.ulaval.ca/2008/25766/25766.pdf.
Full textAndersson, Jenny. "Dissecting the photosystem II light-harvesting antenna." Doctoral thesis, Umeå University, Plant Physiology, 2003. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-25.
Full textIn photosynthesis, sunlight is converted into chemical energy that is stored mainly as carbohydrates and supplies basically all life on Earth with energy.
In order to efficiently absorb the light energy, plants have developed the outer light harvesting antenna, which is composed of ten different protein subunits (LHC) that bind chlorophyll a and b as well as different carotenoids. In addition to the light harvesting function, the antenna has the capacity to dissipate excess energy as heat (feedback de-excitation or qE), which is crucial to avoid oxidative damage under conditions of high excitation pressure. Another regulatory function in the antenna is the state transitions in which the distribution of the trimeric LHC II between photosystem I (PS I) and II is controlled. The same ten antenna proteins are conserved in all higher plants and based on evolutionary arguments this has led to the suggestion that each protein has a specific function.
I have investigated the functions of individual antenna proteins of PS II (Lhcb proteins) by antisense inhibition in the model plant Arabidopsis thaliana. Four antisense lines were obtained, in which the target proteins were reduced, in some cases beyond detection level, in other cases small amounts remained.
The results show that CP29 has a unique function as organising the antenna. CP26 can form trimers that substitute for Lhcb1 and Lhcb2 in the antenna structure, but the trimers that accumulate as a response to the lack of Lhcb1 and Lhcb2 cannot take over the LHC II function in state transitions. It has been argued that LHC II is essential for grana stacking, but antisense plants without Lhcb1 and Lhcb2 do form grana. Furthermore, LHC II is necessary to maintain growth rates in very low light.
Numerous biochemical evidences have suggested that CP29 and/or CP26 were crucial for feedback de-excitation. Analysis of two antisense lines each lacking one of these proteins clearly shows that there is no direct involvement of either CP29 or CP26 in this process. Investigation of the other antisense lines shows that no Lhcb protein is indispensable for qE. A model for feedback de-excitation is presented in which PsbS plays a major role.
The positions of the minor antenna proteins in the PS II supercomplex were established by comparisons of transmission electron micrographs of supercomplexes from the wild type and antisense plants.
A fitness experiment was conducted where the antisense plants were grown in the field and seed production was used to estimate the fitness of the different genotypes. Based on the results from this experiment it is concluded that each Lhcb protein is important, because all antisense lines show reduced fitness in the field.
Fondom, Nicolas Yebit. "PHYSIOLOGICAL AND BIOCHEMICAL ADAPTATIONS IN SOME CAM SPECIES UNDER NATURAL CONDITIONS: THE IMPORTANCE OF LEAF ANATOMY." Oxford, Ohio : Miami University, 2009. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=miami1260552594.
Full textRockholm, David C. "Purification and characterization of violaxanthin de-epoxidase, an enzyme of the xanthophyll cycle." Thesis, 1995. http://hdl.handle.net/10125/9479.
Full textKale, Aniket. "Purification of zein and xanthophylls from corn by process chromatography /." 2006. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:3242886.
Full textSource: Dissertation Abstracts International, Volume: 67-11, Section: B, page: 6128. Adviser: Munir Cheryan. Includes bibliographical references (leaves 128-137) Available on microfilm from Pro Quest Information and Learning.
Yen, Wen Jye, and 晏文潔. "Isolation of Xanthophylls from Orange Peels and Their Effects on the Oxidation Stability of Vegetable Oil." Thesis, 1993. http://ndltd.ncl.edu.tw/handle/11258131833693462738.
Full text輔仁大學
食品營養學系
81
Carotenoids are important biological compounds, and some of them have been found effective against oxidation and skin cancer. Xanthophylls are important in the pigmentation of foods. However, the antioxidant action of xanthophylls remains unknow. The objective of this study is (1) to pre- pare xanthophylls by open column chromatography and compare the separation efficiency of xanthophylls with various ad- sorbents; (2) to identify xanthophylls by HPLC and spectrum analysis; (3) to investigate the antioxidant action of each xanthophyll when adding to vegetable oil. Results implied that the best separation efficiency of xanthophylls was achieved with cellulose as adsorbent, followed by magnesium oxide and calcium hydroxide. Purity of each xanthophyll was in the same order. Six bands of beta- cryptoxanthin, lutein 5,6-epoxide, violeoxanthin, 13-cis-vio- laxanthin, violaxanthin and sinesiaxanthin were resolved for cellulose, and four bands of beta-cryptoxanthin, violeoxan- thin, 13-cis-violaxanthin and violaxanthin were resolved for magnesium oxide. As for calcium hydroxide, only three bands were resolved, which included violeoxanthin, violaxanthin and sinesiaxanthin. A new reversed-phase HPLC solvent system of acetonitrile /methanol/ethyl acetate (80:10:10, v/v/v ) was developed to separate xanthophylls in orange peels. The flow rate was set at 0.7ml/min in the first 20 min and increased to 2.0 ml/min thereafter, and detection was set at 450nm and sensitivity at 0.2 AUFS. Ten pigments, sinesiaxanthin, neoxanthin, cis-neo- xanthin, violaxanthin, 13-cis- violaxanthin, violeoxanthin, lutein 5,6-epoxide, lutein, lutein 5,8-epoxide and beta-cry- ptoxanthin were found in Valencia orange peels, while seven pigments, sinesiaxanthin, neoxanthin, violaxanthin, 13-cis- violaxanthin, violeoxanthin, lutein and beta-cryptoxanthin were found in Taiwan orange peels.
Liu, Cheng-Ju, and 劉千如. "A study on Pigment and Xanthophylls Content in the Difference Degree of Chlorophyll b-Deficient Mutants of Rice (Oryza sativa)." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/80049356964348329175.
Full textGilmore, Adam Matthew. "Biochemistry of xanthophyll-dependent non-photochemical fluorescence quenching in isolated chloroplasts." Thesis, 1992. http://hdl.handle.net/10125/9472.
Full textLeandro, Filipa Ferreira. "Effects of thermal stress on the photoinactivation and repair of photosystem II in a xanthophyll cycledeficient green alga." Master's thesis, 2021. http://hdl.handle.net/10773/33639.
Full textA fotossíntese e a produtividade primária dependem profundamente da temperatura. Temperaturas extremamente altas ou baixas afetam os mecanismos enzimáticos de fotoproteção (ciclo das xantofilas) e exacerbam os danos provocados pela irradiação elevada no fotossistema II (PSII). Uma hipótese recentemente proposta afirma que o stress abiótico, incluindo frio e calor moderado, aumenta a fotoinibição da fotossíntese não por efeitos diretos no PSII, mas sim pela inibição dos mecanismos de reparação. Este trabalho pretende testar essa hipótese num grupo ainda inexplorado de algas verdes (Bryopsidales) que não possuem um ciclo das xantofilas funcional. Para testar esta hipótese, recorremos a medições da fluorescência da clorofila a, sob stress luminoso e térmico, e posterior quantificação da proteína D1, através da técnica do Western blot. Os nossos resultados mostraram que, para este grupo de algas, a hipótese acima mencionada, não é aplicável, pois os stresses abióticos afetaram não apenas os mecanismos de reparo, mas também exacerbaram a fotoinibição. Consequentemente, o grupo de algas verdes (Bryopsidales) apresentou um grande potencial para futuros estudos no âmbito da investigação dos mecanismos de reparação do fotossistema II.
Mestrado em Biologia Aplicada
Scherrers, Roger [Verfasser]. "Carotinoide und Sauerstoff : antioxidative Eigenschaften von aromatischen und nicht aromatischen Xanthophyllen / vorgelegt von Roger Scherrers." 2006. http://d-nb.info/982670982/34.
Full textPoon, Wing Yee Louisa. "Comparative carotenoid and xanthophyll identification, accumulation, and retention as affected by the rp and RP genes in different colored carrots (Daucus carota)." 1997. http://catalog.hathitrust.org/api/volumes/oclc/39099946.html.
Full textTypescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 98-102).