Thèses sur le sujet « Riboflavin »
Créez une référence correcte selon les styles APA, MLA, Chicago, Harvard et plusieurs autres
Consultez les 50 meilleures thèses pour votre recherche sur le sujet « Riboflavin ».
À côté de chaque source dans la liste de références il y a un bouton « Ajouter à la bibliographie ». Cliquez sur ce bouton, et nous générerons automatiquement la référence bibliographique pour la source choisie selon votre style de citation préféré : APA, MLA, Harvard, Vancouver, Chicago, etc.
Vous pouvez aussi télécharger le texte intégral de la publication scolaire au format pdf et consulter son résumé en ligne lorsque ces informations sont inclues dans les métadonnées.
Parcourez les thèses sur diverses disciplines et organisez correctement votre bibliographie.
Grippa, Juliana Malvestio. « Reatividade das espécies heme-Fe metmioglobina e oximioglobina frente ao estado singlete e triplete excitado da riboflavina ». Universidade de São Paulo, 2014. http://www.teses.usp.br/teses/disponiveis/75/75133/tde-02072014-144920/.
Texte intégralThe fresh meat pigment oxymyoglobin, MbFe(II)O2, and its oxidized form metmyoglobin, MbFe(III), are both oxidized by riboflavin as photosensitizer. The reaction of MbFe(II)O2 and MbFe(III) with triplet-state riboflavin, 3Rib, involves the pigment protein, which is oxidatively cleaved or dimerized as shown by SDS-PAGE and Western-blotting, while the heme iron center is not oxidized. The over-all rate constant for oxidation of MbFe(II)O2 by 3Rib is (3.0 ± 0.5) 109 L·mol-1·s-1 and (3.1 ± 0.4) 109 L·mol-1·s-1 for MbFe(III) in aqueous 0.20 mol·L-1 NaCl phosphate buffer of pH 7.4 at 25 °C as determined by transient absorption laser flash photolysis. The high rates are rationalized by ground state hydrophobic interactions as detected as static quenching of fluorescence from singlet-excited state riboflavin by myoglobins using single photon counting time resolved fluorescence spectroscopy and a Stern-Volmer approach. Binding of riboflavin to MbFe(III) has Ka = (1.2 ± 0.2) 104 mol·L-1 at 25 °C with ΔHo = -112 ± 22 kJ·mol-1 and ΔSo = -296 ± 75 J·mol-1·K-1. For meat, riboflavin is concluded to be a photosensitizer for protein oxidation but not for discoloration.
Subbotina, Beztsinna Nataliia. « Riboflavin-based amphiphiles for tumour-targeted nanosystems ». Thesis, Bordeaux, 2015. http://www.theses.fr/2015BORD0254/document.
Texte intégralRiboflavin (RF) is an essential vitamin for cell growth and development. It possesses interesting physicochemical properties and is internalized by the cells through specific transporters. The first aim of this study was to prepare amphiphile derivatives of RF (RFA) and study their auto-assembly. The second aim was to insert RFA into established drug delivery systems and test their tumour-targeting potential in vitro and in vivo. RFA were prepared by the molecule functionalization with lipid moieties in different positions. One of them, a phospholipid-like derivative (RfdiC14) was able to self-assembly in aqueous solutions into μm-sized 3D objects constituted from slightly curved multilayer lamellas. The bilayer architecture and dynamics were very different from ordinary phospholipids. In contrast, the insertion of small amount of RfdiC14 in a liposome did not influence membrane dynamics and physicochemical characteristics. RfdiC14-functionalised liposomes displayed high and specific uptake in vitro in A431, PC3 cells and HUVECs. The efficiency of RF targeting was also tested in vivo. For that purpose, liposome composition was optimized and a new RF amphiphile with a PEG spacer between RF and lipid was prepared. The tumour accumulation of the liposomes labelled with ICG was studied by photoacoustic imaging in A431 tumour model. The biodistribution of DiR labelled liposomes was accessed by combined μCT/FMT imaging in PC3 tumour model. The results show slight improvement of the tumour accumulation in A431 xenographts and the enhancement of vascular targeting in PC3 tumour model. The overall biodistribution of the RF-targeted liposomes was comparable to control
Machado, Daisy 1981. « Modulação da agressividade do melanoma por flavinas ». [s.n.], 2012. http://repositorio.unicamp.br/jspui/handle/REPOSIP/314042.
Texte intégralTese (doutorado) - Universidade Estadual de Campinas, Instituto de Biologia
Made available in DSpace on 2018-08-20T22:59:08Z (GMT). No. of bitstreams: 1 Machado_Daisy_D.pdf: 7339714 bytes, checksum: b126414072e5dc8abcca091c7af0fdbf (MD5) Previous issue date: 2012
Resumo: Melanoma é o tipo mais agressivo de tumor de pele e uma das principais causas de morte por tumor de pele, devido a sua alta capacidade metastática. Em termos de estratégias terapêuticas de combate ao melanoma tem-se dado ênfase no controle da resistência e da metástase. Nosso grupo de pesquisa observou que a riboflavina irradiada (RFi) induz apoptose de células de câncer de próstata, renal e leucemia mielóide. Portanto, o objetivo geral deste trabalho foi utilizar a RFi para modular química e geneticamente as vias de transdução de sinal associadas com a sobrevivência, resistência e agressividade do melanoma. Assim, neste trabalho estão apresentados os dados sobre a influência da RFi em diferentes aspectos metabólicos das células de melanoma murino (B16F10), tais como: citotoxicidade, adesão, invasão, migração, capacidade de formação de colônia e em mediadores de transdução de sinal: Src quinase, mTOR e componentes da via sonic hedgehog. Em todos os experimentos a riboflavina (RF) foi previamente irradiada com UVA (dose de 9 J/cm²). Foi observado inibição da proliferação celular com valor de IC50 de 50 ?M. De forma interessante, RFi na faixa de concentração de nanomolar foi eficiente na inibição da formação de colônias. Além disso, causou a redução da adesão das células B16F10, quando utilizada na concentração de 1?M. A capacidade de migração e invasão das células de melanoma foi reduzida na presença da RFi, nas concentrações de 1 e 30 ?M respectivamente, porém a resposta foi independente da dose. A atividade e expressão das metaloproteinases foram diminuídas na presença de RFi, indicando inibição na capacidade de invasão. Sob o contexto de sinalização a RFi modulou negativamente a via sonic hedgehog, PI3K/mTOR e aumentou a expressão da p53 e PTEN. O conjunto de resultados obtidos nesse trabalho mostra que flavinas são candidatas promissoras para a intervenção farmacológica do melanoma
Abstract: Melanoma is the most aggressive type of skin disorder and a major cause of death by skin's disease due to its highly metastatic ability. In terms of melanoma therapeutic strategies has given emphasis on control of resistance and metastasis. Our group observed that irradiated riboflavin (RF) induces apoptosis of prostate cancer cells, kidney cancer cells and myeloid leukemia. Therefore, the goal of this study was to employ irradiated RF for modulating chemical and genetically signal pathways associated with melanoma survival, resistance and aggressiveness. Thus, in this manuscript data about the influence of RF in different cellular metabolic aspects of murine melanoma (B16F10) such as cytotoxicity, adhesion, invasion, migration, colony formation and signal transduction mediators Src kinase, mTOR and sonic hedgehog components, will be presented. In all experiments the RF was previously irradiated with UVA (dose of 9 J/cm²). Inhibition of cell proliferation was observed with IC50 value of 50 ?M. Interestingly, RF in a nanomolar concentration inhibited the formation of colonies. In addition, 1 ?M irradiated RF caused a reduction of B16F10 cells adhesion. The ability of migration and invasion of melanoma cells was reduced in the presence of RF, however, those cells response was dose-independent. The activity and expression of metalloproteinases were diminished indicating reduction of cellular invasiveness capacity. Sonic hedgehog and PI3K/mTOR pathways were negatively modulated and the expression of p53 and PTEN were increased in melanoma cells treated with irradiated RF. The findings showed in this study brought out flavins as promising candidates for pharmacological intervention of melanoma
Doutorado
Bioquimica
Doutor em Biologia Funcional e Molecular
Ohara, Andre 1989. « Isolamento e seleção de leveduras silvestres de biomas do Estado de São Paulo com potencial para produção de lipase e vitaminas do complexo B ». [s.n.], 2014. http://repositorio.unicamp.br/jspui/handle/REPOSIP/256642.
Texte intégralDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos
Made available in DSpace on 2018-08-24T18:55:36Z (GMT). No. of bitstreams: 1 Ohara_Andre_M.pdf: 6935792 bytes, checksum: 553cf8492d7af096c35b5c595ec6e3a1 (MD5) Previous issue date: 2014
Resumo: A bioprospecção de micro-organismos representa um grande potencial tecnológico para produção de biocompostos de interesse comercial. Dentre estes compostos estão as enzimas lipolíticas, como as lipases (triacilglicerol acil-hidrolases EC 3.1.1.3) que apresentam um enorme potencial para aplicações biotecnológicas. Outro tipo de biocomposto de relevante interesse comercial são as vitaminas do complexo B, as quais possuem função essencial na atividade de enzimas que regulam reações do metabolismo. Desta forma, o objetivo desse trabalho foi isolar e selecionar linhagens de leveduras do solo de diferentes biomas do Estado de São Paulo com potencial para produção de lipase e de vitaminas do complexo B (biotina e riboflavina). Para tanto, foram isoladas 132 leveduras de amostras de solos provenientes da Mata Atlântica e da região de transição (Mata Atlântica e Cerrado). Essas linhagens foram depositadas na coleção de micro-organismos do laboratório de Bioquímica de Alimentos da FEA-UNICAMP, que já contava com 300 leveduras provenientes da região de Cerrado. As 432 linhagens presentes na coleção foram então avaliadas quanto ao potencial para a produção de lipase extracelular através de seleção em meio sólido diferencial e cultivo em meio líquido, sendo a atividade de lipase determinada no sobrenadante por titulometria de neutralização. O potencial para a produção de biotina e riboflavina extracelular foi avaliada por meio de seleção em meio de cultivo líquido, sendo as concentrações das vitaminas determinadas no sobrenadante por espectrofotometria e fluorimetria. Desta forma 33 leveduras apresentaram potencial para produção de lipase alcançando valores de atividade enzimática que variaram de 6,51 U/mL a 21,44 U/mL. Em relação à produção das vitaminas do complexo B, 38 linhagens apresentaram concentrações de biotina no sobrenadante do cultivo que variaram de 0,28 µg/mL a 18,61 µg/mL e 64 linhagens apresentaram concentrações de riboflavina que variaram de 0,03 µg/mL a 0,77 µg/mL. A linhagem RP.C153 apresentou potencial para produção de lipase e riboflavina, enquanto a linhagem RP.J1308 para produção de lipase e biotina. A linhagem RP.C153 foi classificada como Pichia caribbica e a linhagem RP.J1308 como Candida oleophila
Abstract: The bioprospection of microorganisms represents a great technological potential for the production of biocompounds of commercial interest. Among these compounds are the lipolytic enzymes, such as lipases (triacilglicerol acilhidrolases EC 3.1.1.3) which have currently a huge potential for biotechnological applications. B vitamins are another type of biocompound with relevant commercial interest, which have essential role in the activity of enzymes that regulate metabolic reactions in living organisms. Therefore, the aim of this work was to isolate and select strains of yeasts from the soil of different biomes present in the State of São Paulo for the biotechnological production of lipase and B vitamins (biotin and riboflavin). Thus, 132 yeasts were isolated from soil samples of the Atlantic Forest (Ilha Bela - SP) and the transition region between the Atlantic Forest and Savanna (Campinas - SP). These strains were deposited in the collection of microorganisms of the Food Biochemistry Laboratory FEA - UNICAMP, which already had 300 yeasts from the Savanna region (Ribeirão Preto - SP). Therefore 432 strains present in the collection were then evaluated for their potential to produce extracellular lipase by selection on solid selective differential and liquid medium culture, and the enzyme activity in the supernatant was determined by neutralization titration. The potential production of extracellular biotin and riboflavin was assessed by selection in medium liquid culture, and the concentrations of those vitamins were measured in the supernatant by spectrophotometry and fluorimetry. Therefore 33 yeasts demonstrated potential for the production of lipase, reaching values of enzymatic activity ranging from 6.51 U/mL to 21.44 U/mL. In relation to the production of B vitamins, 38 strains presented concentrations of biotin in the supernatant culture ranging from 0.28 µg/mL to 18.61 µg/mL and 64 strains demonstrated concentrations of riboflavin ranging from 0.03 µg/mL to 0.77 µg/mL. The strain RP.C153 presented potential for production of lipase and riboflavin, while strain RP.J1308 for production of lipase and biotin. The RP.C153 strain was classified as Pichia caribbica and RP.J1308 strain as Candida oleophila
Mestrado
Ciência de Alimentos
Mestre em Ciência de Alimentos
Øyangen, Julia. « Photoprotection of riboflavin containing beverages ». Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for fysikk, 2012. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-18386.
Texte intégralYates, Catherine Ann. « Gastrointestinal development and riboflavin deficiency ». Thesis, University of Sheffield, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.312293.
Texte intégralHuang, Se-Ne. « Cellular translocation mechanism of Riboflavin / ». The Ohio State University, 2001. http://rave.ohiolink.edu/etdc/view?acc_num=osu1486572165275525.
Texte intégralRiether, Gustavo Tokoro. « Aspectos do mecanismo de formação 3-metil-2-buteno-1-tiol em cerveja e a reatividade dos iso-α-ácidos ». Universidade de São Paulo, 2010. http://www.teses.usp.br/teses/disponiveis/75/75132/tde-21092010-091119/.
Texte intégralBeer is a fermented alcoholic beverage based on starch and flavored by hops (Humulus lupulus L.). The α-acids are extracted from hop cones and isomerize into iso-α-acids (IAAs) during the wort boiling, in cis- and trans- configuration, providing foam quality and the characteristic bitter taste of beer. In this work, is reported that these compounds undergo degradation photosensitized by flavins (Φ = 4,8x10-3 mol einstein-1), even in the presence of phenolic compounds (ferulic acid, Φ = 2,0x10-3 mol einstein-1) in 10-fold molar excess, suggesting that radicals formed during the deactivation of triplet excited state of riboflavin by phenolic compounds may be involved in the degradation of IAAs. Dimers and trimers derived from ferulic and p-coumaric acids were identified by LC-ESI-IT-MS as the main photoproducts of the phenolic compounds. We report the reactivity of the different diastereoisomers of IAAs towards the 2,2-diphenyl-1-picrylhydrazyl (DPPH•) radical, as a model for peroxyl radical, k2 = 0,41 e 1,3 L mol-1 s-1 for the reaction with cis-IAA and trans-IAA in ethanol acidified with 1% of formic acid, at the temperature of 25 °C, respectively. These specifics rate constants suggest that the degradation of the bitter acids via thermal reactions in an radicaloid process is important during the storage of the product since the reaction rate constant for IAAs and the DPPH• radical are competitive with the reaction rate constants for naturally occurring antioxidants in beer with the DPPH• radical ([ferulic acid] = 0,2mg/Lbeer; k2 = 1,18.102 M-1s-1). The analysis of the thermodynamical data (IAAs mixture, ΔH‡ = 25 kJ mol-1 e ΔS‡ = -155 J mol-1 K-1) suggest a HAT/PCET oxidation mechanism of IAAs by DPPH• radical. The difference of reactivity observed for the diastereoisomers (cis-/trans-) is possibly related to the stereochemical arrangement of the isohexonoyl and prenyl side chains connected to C(4) and C(5) carbons, respectively. In this way, is suggested that the spatial proximity of the insaturation sites in the trans- species lead to a increase in electronic density or due to a statistical factor since the allylic-H are close spatially, which favors the oxidation via radicaloid.
Munive, Mendez María Claudia del Pilar, et Quispe Flavia Jimena Cardenas. « Evaluación in vitro del efecto inhibitorio de la terapia fotodinámica sobre Streptococcus mutans (ATCC® 25175) y Streptococcus sanguinis (ATCC® 10556) en presencia y ausencia de riboflavina ». Bachelor's thesis, Universidad Peruana de Ciencias Aplicadas (UPC), 2020. http://hdl.handle.net/10757/651668.
Texte intégralObjective: To evaluate the inhibitory effect of photodynamic therapy (TPD) with blue Light Emitting Diode (LED) on Streptococcus mutans and Streptococcus sanguinis in presence and absence of riboflavin (E-101). Materials and methods: Four treatments were performed in presence and absence of blue LED and riboflavin (0.5%) exposure on Streptococcus mutans and Streptococcus sanguinis. The bacteria were grown in BHI medium and the unit of measurement used was the colony forming units (CFU / ml). Results: Photoactivation with blue LED light at 40 seconds had no inhibitory effect on S. mutans and S. sanguinis. However, when performing photodynamic therapy in presence of riboflavin, it was observed that bacterial growth was lower (p <0.05). Likewise, it was identified that bacterial viability of S. sanguinis is lower than S. mutans, with 40% and 66% respectively. Conclusions: It is concluded that riboflavin has a significant inhibitory effect on the bacterial viability of S. mutans and S. sanguinis.
Tesis
McClelland, David Andrew. « The refolding of riboflavin binding protein ». Thesis, University of Stirling, 1996. http://hdl.handle.net/1893/3408.
Texte intégralYettella, V. Ramesh Reddy. « Riboflavin Photosensitized Oxidation of Amino Acids ». The Ohio State University, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=osu1217897521.
Texte intégralKim, Ryuryun Verfasser], et Markus [Akademischer Betreuer] [Fischer. « Biosynthesis of Vitamin B2 (Riboflavin) : Studies on the Reaction Mechanism of Riboflavin Synthase / Ryuryun Kim. Betreuer : Markus Fischer ». Hamburg : Staats- und Universitätsbibliothek Hamburg, 2012. http://d-nb.info/1023947307/34.
Texte intégralRamsperger, Arne. « Strukturanalyse der Riboflavin-Synthase aus Methanococcus jannaschii ». [S.l.] : [s.n.], 2005. http://deposit.ddb.de/cgi-bin/dokserv?idn=978931084.
Texte intégralWang, Fan. « UVA/Riboflavin-Induced Apoptosis in Mouse Cornea ». Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2014. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-133626.
Texte intégralDieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG-geförderten) Allianz- bzw. Nationallizenz frei zugänglich
Abdel-Kader, Z. M. « Diffusion of riboflavin under thermal sterilisation conditions ». Thesis, University of Leeds, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.355374.
Texte intégralWang, Fan. « UVA/Riboflavin-Induced Apoptosis in Mouse Cornea ». Karger, 2008. https://tud.qucosa.de/id/qucosa%3A27521.
Texte intégralDieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG-geförderten) Allianz- bzw. Nationallizenz frei zugänglich.
Azurdia, Diana Eileen. « The regulation of Riboflavin biosynthesis in Eschrichia coli ». Diss., Restricted to subscribing institutions, 2010. http://proquest.umi.com/pqdweb?did=2026893431&sid=1&Fmt=2&clientId=1564&RQT=309&VName=PQD.
Texte intégralKlaumünzer, Bastian. « Quantenchemische und molekulardynamische Untersuchungen zur Photoanregung von Riboflavin ». Phd thesis, Universität Potsdam, 2012. http://opus.kobv.de/ubp/volltexte/2013/6317/.
Texte intégralThe photophysics and photochemistry of flavins are due to their biological function, in particular of flavoproteins, of great interest. Flavoproteins play a major role in a variety of biological processes, eg Bioluminescence, removal of free radicals, resulting in oxidative stress, photosynthesis and DNA repair. The spectroscopic properties of the flavin cofactor make this a natural reporter for changes within the active site. Therefore flavoproteins are one of the most studied enzyme families. A biological activity of the flavin via an electronically excited state, which then performs a function of the amino acid environment, a specific mechanism to a biological process (photo cycle). An important analytical tool for the understanding of the initial step of the photoexcitation flavins are the electronic and vibrational spectroscopy. In this study, the processes of riboflavin (RF) during and after optical excitation illuminated by theoretical means. These quantum chemical calculations for the vibrational spectra (vibrational) of riboflavin, or vitamin B2 lactoflavin also been mentioned, the basic molecule of biological chromophores blue light receptors in the electronic ground state and the lowest excited state performed. Furthermore, vibronic (vibrational + electronic) absorption spectra and vibronic emission spectra were calculated. The calculated vibrational and electronic spectra are in good qualitative and quantitative agreement with measured values, and help to assign the experimental signals of the photo-excitation of flavins. Immediately after photoexcitation a loss of the double bond character was observed in the polar region of the ring system, leading to the vibronic fine structure in the electronic absorption and emission spectrum. It showed also that in addition to the vibronic effects, the solvent effects are important for a quantitative understanding of the photophysics of flavins in solution. To decipher details of the optical excitation process as initial, elementary step in signal transduction, ultrafast were performed (femtosecond-resolved) experiments that investigate the photoactivation of the flavin. This work will contribute to a further understanding and interpretation of these experiments by studying the post-excitation vibrational dynamics of riboflavin and riboflavin mikrosolvatisiertem. To a 200 fs long molecular dynamics in excited states was considered. By the analysis of characteristic atomic motions and by the calculations of time-resolved emission spectra, it was found that, after the optical excitation oscillations in the ring system of the riboflavin used. Using these calculations, the energy redistribution in the excited state can be observed. In addition to the theoretical studies of riboflavin in the gas phase and in solution, a model for a BLUF (Blue Light Photoreceptor Using flavin) domain, a flavin-use photoreceptor created. It is shown that one can apply the analytical methods employed in this work and to biologically relevant systems.
King, Joan M. « Riboflavin Photosensitized Singlet Oxygen Oxidation of Vitamin D ». The Ohio State University, 1996. http://rave.ohiolink.edu/etdc/view?acc_num=osu1392814029.
Texte intégralBradley, Dondeena G. « Riboflavin photosensitized singlet oxygen oxidation in milk products / ». The Ohio State University, 1991. http://rave.ohiolink.edu/etdc/view?acc_num=osu148775817823755.
Texte intégralMachado, Daisy 1981. « Avaliação da citotoxicidade e fototoxicidade da riboflavina : determinação de marcadores moleculares de inflamação, senescencia e morte celular ». [s.n.], 2009. http://repositorio.unicamp.br/jspui/handle/REPOSIP/314049.
Texte intégralDissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia
Made available in DSpace on 2018-08-13T19:46:07Z (GMT). No. of bitstreams: 1 Machado_Daisy_M.pdf: 1450123 bytes, checksum: e8dc961f855a7ea88daa10bb8ee00685 (MD5) Previous issue date: 2009
Resumo: A riboflavina (RF) é uma vitamina hidrossolúvel pertencente ao complexo vitamínico B2 e precursora das coenzimas FMN e FAD. Além da função biológica como componente de coenzimas, a RF apresenta atividade antitumoral e fotossensibilizante. A proposta principal desse estudo se baseou na avaliação da fototoxicidade da RF, bem como na determinação de marcadores moleculares da inflamação, senescência e morte celular, ações deletérias normalmente desencadeadas pela radiação UVA. Os resultados obtidos indicam que a RF tem potencial aplicação na terapia fotodinâmica, levando se em conta os modelos celulares utilizados, fibroblastos (BALB/c 3T3) e queratinócitos humanos (HaCaT). As células BALB/c 3T3 tratadas com RF 6,0 mM e dose de 5 J/cm² de radiação UVA, apresentaram indução de apoptose principalmente pela via intrínseca. A indução de senescência foi evidenciada pelo aumento da p-caveolina e aumento da atividade da MMP-2 (principal protease responsável pela degradação de colágeno). De acordo com os níveis de NFkB e p- IKKa/b, a RF não alterou significativamente o processo de inflamação desencadeado pela radiação UVA. Nas células HaCaT, o tratamento com 5,0 mM de RF e dose de 5 J/cm² de radiação UVA levou a ativação da apoptose induzida tanto pela via extrínseca como pela intrínseca. O aumento nos níveis de p-caveolina, p21 e da atividade das MMPs-2 e -9 sugerem à indução de processo de senescência precoce também nos queratinócitos. Além disto, a diminuição da expressão do NF?B indica que o mesmo esteja se translocando para o núcleo e, portanto, regulando a resposta inflamatória. Outro aspecto avaliado foi a influência do copolímero F-127 na fototoxicidade da RF. A irradiação do hidrogel contendo F-127 e riboflavina manteve a propriedade fototóxica da mesma. Nossos dados sugerem que a RF apresenta potencial para uso em terapia fotodinâmica, uma vez que a mesma se mostrou fototóxica quando irradiada com doses subtóxicas de radiação UVA.
Abstract: Riboflavin (RF) is a water soluble vitamin which belongs to vitamin B2 complex, an essential precursor of FMN and FAD coenzymes. Besides being a component of coenzymes, RF displays antitumoral and photossensitizing activities. The main proposal of this study was to evaluate the RF phototoxicity, as well as to determine molecular markers of inflammation, senescence and cellular death, deleterious actions normally triggered by the UVA radiation. Taking into consideration both cell lines used as models, fibroblasts (BALB/c 3T3) and human keratinocytes (HaCaT), the results obtained indicate that RF has potential application in photodynamic therapy. BALB/c 3T3 cells treated with 6.0 µM RF associate with UVA radiation (5 J/cm²) showed apoptosis induction mainly via intrinsic pathway. An increase of p-caveolin and MMP-2 activity (major protease responsible for degradating collagen) evidenced senescence induction. According to NF?B and p-IKKa/ß levels, RF did not significantly change the process of inflammation triggered by UVA radiation, in fibroblast cells. In HaCaT cells 5.0 µM RF associated with UVA radiation (5 J/cm ²) was observed apoptosis induction thorough extrinsic and intrinsic pathways. Senescence process was also observed in keratinocytes as indicated by an increase of pcaveolin, p21 and MMPs-2 and -9 activities. Besides, the decrease of NF?B expression indicates that this transcription factor translocates into the nucleus and in turn, regulates inflammatory response. Other aspect evaluated in this work was the influence of the F-127 in the RF phototoxicity. The irradiation of hydrogel containing F-127 and RF remained RF phototoxicity property. Our findings suggest that RF displays potential for use in photodynamic therapy, once it was phototoxic when irradiated with subtoxic UVA dose
Mestrado
Bioquimica
Mestre em Biologia Funcional e Molecular
Urzêdo, Ana Carolina Borges de 1980. « Foto-oxidação do leite microfiltrado pasteurizado : influência do tipo de embalagem e intensidade da luz ». [s.n.], 2013. http://repositorio.unicamp.br/jspui/handle/REPOSIP/255800.
Texte intégralTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos
Made available in DSpace on 2018-08-23T15:48:33Z (GMT). No. of bitstreams: 1 Urzedo_AnaCarolinaBorgesde_D.pdf: 4425198 bytes, checksum: ca9f39f7b13a21e55c2d558014da6722 (MD5) Previous issue date: 2013
Resumo: A foto-oxidação do leite é o fator determinante na vida de prateleira do leite microfiltrado pasteurizado. A exposição do leite à luz, nas gôndolas dos supermercados, desencadeia a foto-oxidação da riboflavina e das proteínas do leite, provocando mudanças na cor e formação de off-flavors. O objetivo do trabalho foi verificar, em condições reais, a influência do tipo de embalagem e da intensidade da luz na degradação da riboflavina, formação de lumicromo, oxidação de proteína, cor e vida de prateleira do leite desnatado microfiltrado pasteurizado. Leite desnatado microfiltrado pasteurizado foi acondicionado em garrafas de vidro e de polietileno de alta densidade, e armazenados no escuro (controle) e sob incidência de luz (500 e 1200 lux), durante 14 dias de estocagem refrigerada. Análises de espectroscopia de fluorescência da riboflavina, lumicromo, triptofano e ditirosina e análise de cor instrumental foram realizadas para acompanhar a foto-oxidação dos componentes do leite. Para estimar a vida de prateleira do leite microfiltrado pasteurizado, sob diferentes condições de luz e embalagem, contagens de micro-organismos mesófilos aeróbios e análise sensorial com assessores treinados, teste de aceitação e intenção de compra foram realizados durante o tempo de armazenamento refrigerado. Assessores foram treinados para avaliação da cor, aroma e sabor característicos de leite desnatado e de leite desnatado oxidado. Aos 14 dias de estocagem refrigerada, 76,1% da riboflavina foi degradada no leite exposto à radiação de 500 lux. Já a 1200 lux, esse valor foi de 86,4%. A degradação da riboflavina, a formação de lumicromo e a fotodegradação do triptofano foram maiores e mais rápidas quando a intensidade de luz foi mais intensa (1200 lux). Durante o armazenamento refrigerado, a oxidação das proteínas resultou em desnovelamento da estrutura terciária, e consequentemente, em exposição e posterior degradação do triptofano. No período estudado, houve somente formação de ditirosina para os leites submetidos à intensidade de luz mis intensa (1200 lux). A vida de prateleira dos leites armazenados no escuro (controle) foi de 10 a 14 dias. O aparecimento do sabor oxidado, proveniente da foto-oxidação dos componentes do leite, foi o parâmetro determinante para o fim da vida de prateleira dos leites armazenados sob luz. O tipo de embalagem somente influenciou a vida de prateleira do leite, quando a intensidade de exposição à luz foi mais baixa (500 lux). Nessa intensidade de radiação luminosa, a vida de prateleira do leite pasteurizado aumentou de 4-6 dias para 10-13 dias, quando a embalagem de vidro foi substituída pela de polietileno
Abstract: Photo-oxidation of milk is probably the main cause for the end of shelf life of a microfiltered pasteurized milk. Milk is inevitably exposed to light on the supermarket shelves, which triggers the photo-oxidation of riboflavin and milk proteins, affecting the sensory quality with changes in color and formation of off-flavors. The objective was to verify, in real conditions, the influence of the type of packaging and the light intensity on the riboflavin degradation, protein oxidation, color, shelf life of microfiltered pasteurized skim milk. After processing, milk was packaged in glass and high density polyethylene bottles and stored in the dark (control) and under influence of light (500 and 1200 lux), during 14 days of refrigerated storage. Analyses of fluorescence spectroscopy of riboflavin, lumicrome, tryptophan and dityrosine and instrumental color were performed to monitor the photo-oxidation of milk components. The shelf life of pasteurized microfiltered skim milk, under different light conditions and packaging was estimated by standard plate count of aerobic mesophilic and sensory analysis with trained assessors, acceptance testing, and purchase intent, during refrigerated storage time. Assessors were trained to evaluate sensorially the color, aroma and flavor of skim milk and oxidized skim milk. At 14 days of refrigerated storage, 76.1% of riboflavin was degraded in milk exposed to radiation of 500 lux. However, at 1200 lux, degradation of riboflavin reached 86.4% of its initial content in milk. Riboflavin degradation, lumicrome and tryptophan formation were higher and faster when light intensity was more intense (1200 lux). During storage time, the oxidation of proteins resulted in the tertiary structure unfolding, and exposure and subsequent degradation of tryptophan. During this period of time, there was formation of dityrosine only for the milks exposed to more intense light radiation (1200 lux). The shelf life of milk stored in the dark (control) was 10-14 days. The development of oxidized flavor, derived from the photo-oxidation of milk components, was the main parameter for determining the ending of the shelf life of milk stored under light. Packaging material influenced the milk shelf life when the intensity of light was lower (500 lux). In this condition, the shelf life of pasteurized milk increased from 10-13 days to 4-6 days when the glass container was replaced by polyethylene bottle
Doutorado
Tecnologia de Alimentos
Doutora em Tecnologia de Alimentos
Melo, Julliane Tamara Ara?jo de. « An?lise da express?o de APE1 ap?s estresse oxidativo induzido em c?lulas proficientes e deficientes na via de reparo por excis?o de nucleot?deos ». Universidade Federal do Rio Grande do Norte, 2010. http://repositorio.ufrn.br:8080/jspui/handle/123456789/13055.
Texte intégralConselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico
Riboflavin is a vitamin very important in aerobic organisms, as a precursor of many coenzymes involved in the electron transporter chain. However, after photosensitization of riboflavin with UV or visible light, it generates reactive oxygen species (ROS), which can oxidize the DNA. The repair of oxidative lesions on DNA occurs through the base excision repair pathway (BER), where APE1 endonuclease plays a central role. On the other hand, the nucleotide excision repair pathway (NER) repairs helix-distorting lesions. Recently, it was described the participation of NERproteins in the repair of oxidative damage and in stimulation of repair function fromAPE1. The aim of this research was to evaluate the cytotoxic effects of photosensitized riboflavin (RF*) in cells proficient and deficient in NER, correlating with APE1 expression. For this propose, the cells were treated with RF* and it was performed the cell viability assay, extraction of whole proteins, cells fractionation, immunoblotting, indirect immunofluorescence and analysis of polymorphisms of BER gens. The results evidenced that cells deficient in XPA and CSB proteins were more sensitive to RF*. However, XPC-deficient cells presented similar resistance to MRC5- SV cells, which is proficient in NER. These results indicate that XPA and CSB proteins have an important role on repair of oxidative lesions induced by RF*. Additionally, it was evidenced that single nucleotide polymorphisms (SNPs) in BER enzymes may influence in sensitivity of NER-deficient cell lines. Concerning the APE1 expression, the results showed that expression of this protein after treatment with RF* only changed in XPC-deficient cells. Though, it was observed that APE1 is recruited and is bound to chromatin in MRC5-SV and XPA cells after treatment with RF*. The results also showed the induction of DNA damage after treatment with RF*, through the analysis of-H2AX, since the treatment promoted an increase of endogenous levels of this phosphorylated protein, which acts signaling double strand-break on DNA. On the other hand, in XPC-deficient cells, regardless of resistance of RF*, the endogenous levels of APE1 are extremely reduced when compared with other cell lines and APE1 is not bound to chromatin after treatment with RF*. These results conclude that RF* was able to induce cell death in NERdeficient cells, where XPA and CSB cells were more sensitive when compared with MRC5-SV and XPC-deficient cells. This last result is potentially very interesting, since XPC-deficient cell line presents low levels of APE1. Additionally, the results evidenced that APE1 protein can be involved in the repair of oxidative damage induced by RF*, because APE1 is recruited and bound strongly to chromatin after treatment.
A riboflavina ? uma vitamina de fundamental import?ncia em organismos aer?bios, sendo precursora de importantes coenzimas que participam da cadeia transportadora de el?trons. Contudo, ap?s a sensibiliza??o da riboflavina com luz UV ou luz vis?vel, observou-se a forma??o de esp?cies reativas de oxig?nio (EROs), as quais podem oxidar o DNA. O reparo de les?es oxidativas no DNA ocorre principalmente atrav?s da via de reparo por excis?o de bases (BER), na qual a endonuclease APE1 exerce um papel central. Por sua vez, a via de reparo por excis?o de nucleot?deos (NER) atua reparando les?es no DNA que causam distor??es na dupla h?lice. Recentemente tem sido descrito a participa??o da via NER na remo??o de danos oxidativos e na estimula??o da fun??o de reparo de APE1. Desta forma, o objetivo desta pesquisa foi analisar os efeitos citot?xicos da riboflavina fotossensibilizada (RF*) em c?lulas proficientes e deficientes na via NER, correlacionando ? express?o de APE1. Para tanto, as linhagens proficientes e deficientes no NER foram submetidas ao tratamento com RF* e em seguida foram realizados os ensaios de viabilidade celular, extra??o de prote?nas totais, fracionamento celular, immunoblotting, imunofluoresc?ncia indireta e a an?lise de polimorfismos em genes da via BER. Os resultados evidenciaram perfis de sensibilidade distintos ao estresse oxidativo induzido pela RF*, onde as linhagens XPA e CSB foram mais sens?veis, enquanto a linhagem XPC mostrou resist?ncia similar ? linhagem MRC5-SV, a qual ? proficiente na via NER. Esses resultados indicam que as prote?nas XPA e CSB possuem um importante papel no reparo das les?es oxidativas induzidas pela RF*. Al?m disso, foi demonstrado que polimorfismos em um ?nico nucleot?deo (SNPs) em enzimas do BER podem influenciar na sensibilidade dessas linhagens. Em rela??o ?s an?lises dos n?veis de express?o de APE1, os resultados mostraram que houve altera??o na express?o dessa prote?na ap?s o tratamento com RF* somente na linhagem deficiente em XPC. Por?m, observou-se que APE1 ? recrutada e se torna ligada ? cromatina ap?s o tratamento nas linhagens MRC5-SV e XPA. Os resultados tamb?m comprovaram a indu??o de danos ap?s o tratamento com RF* atrav?s do estudo da prote?na-H2AX, pois o tratamento provocou um aumento nos n?veis end?genos desta prote?na fosforilada, a qual atua na sinaliza??o de quebras de fita dupla no DNA. Por?m, na linhagem XPC, al?m de ter sido observado uma curva de sobreviv?ncia semelhante ? linhagem MRC5-SV, os n?veis end?genos de APE1 s?o significativamente reduzidos quando comparados com as outras linhagens e APE1 n?o se encontra ligada ? cromatina ap?s tratamento com RF*. Conclui-se que a RF* foi capaz de induzir a morte celular em linhagens deficientes no sistema de reparo por excis?o de nucleot?deos, onde as linhagens XPA e CSB foram mais sens?veis quando comparadas ? linhagem normal MRC5-SV e ? linhagem XPC. Este ?ltimo resultado ? potencialmente interessante, considerando que a linhagem XPC apresenta baixos n?veis prot?icos de APE1. Adicionalmente, os resultados comprovaram que a prote?na APE1 pode estar envolvida no reparo de danos oxidativos causados pela RF*, j? que APE1 ? recrutada na cromatina e se liga fortemente a esta ap?s o tratamento.
Kemter, Kristina. « Untersuchungen zur Riboflavin-Synthase und Flavokinase aus verschiedenen Organismen ». [S.l.] : [s.n.], 2002. http://deposit.ddb.de/cgi-bin/dokserv?idn=966109163.
Texte intégralFerreira, Matheus. « The Kinetics and Dynamics of Schizosaccharomyces pombe Riboflavin Kinase ». Thesis, Umeå universitet, Kemiska institutionen, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-150544.
Texte intégralLee, Sungsook. « Studies on the biosynthesis of 5-deazaflavin and riboflavin ». The Ohio State University, 1988. http://rave.ohiolink.edu/etdc/view?acc_num=osu1341848901.
Texte intégralSouza, Bianca Rodrigues de. « Quantificação das vitaminas do complexo B (B1, B2) e vitâmeros das vitaminas B3 e B6 em amostras de pólen apícola desidratado provenientes da Região Sul do Brasil ». Universidade de São Paulo, 2014. http://www.teses.usp.br/teses/disponiveis/9/9131/tde-27052015-141055/.
Texte intégralBee pollen is understood to be the result of agglutination of pollen from flowers, made by worker bees, and nectar through salivary substances, which is collected at the hive entrance. The literature describes that this product contains proteins, carbohydrates, lipids, vitamins, minerals. Previous study with fresh and dehydrated bee pollen, from the city of Pariquera-Açu (São Paulo) showed significant levels of vitamin B1 (thiamine), B2 (riboflavin), presence of B3 (nicotinic acid and nicotinamide) and B6 (pyridoxal, pyridoxamine, piridoxol) vitamins vitamers in its composition which was associated with the local flora explored by bees. Southern Brazil has a differentiated climate, topography and vegetation from other regions, thus requiring verification of vitamin potential of this local product. Also stands out the fact that this region is one of the two largest national producers of bee pollen (Santa Catarina state). This study aimed to quantify the levels of B complex vitamins: vitamins B1, B2, as well as the vitamers of vitamins B3 and B6. Thus, it was collected 28 batches of dehydrated bee pollen from different locations in the South during the period from August 2011 to December 2012. Samples were obtained and subsequently stored at -18 ° C until the analysis time. B vitamins were analyzed by high performance liquid chromatography (HPLC) in bee pollen dehydrated matrix and results were expressed on a dry basis. Among the samples it levels of vitamin B1 varied from 0.46 to 1.83 mg / 100 g; vitamin B2 from 0.40 to 1.86 mg / 100 g; and for vitamin B6, only the pyridoxal and pyridoxamine vitamers could be quantified in all analyzed batches. The pyridoxal had variation between samples from 0.42 to 6,70 mg / 100 g and pyridoxamine from 0.26 to 0.95 mg / 100g. Taking 25 g of bee pollen as suggested for daily intake portion, it was found in a total of 28 samples that 15 were considered sources and 2 rich in thiamine; 19 lots were sources and 3 rich in riboflavin, and; 2 lots were sources and 26 rich in pyridoxine in relation to the Reference Daily Intake (RDI) for adults as provided in Resolução de Diretoria Colegiada (RDC) nº 269, de setembro de 2005.
Schramek, Nicholas. « Kinetische Untersuchungen von Enzymen der Tetrahydrobiopterin-, Riboflavin- und Folsäure-Biosynthesewege ». [S.l.] : [s.n.], 2001. http://deposit.ddb.de/cgi-bin/dokserv?idn=962156507.
Texte intégralBauer, Stefanie. « Röntgenkristallographische Untersuchung von Proteinen der Biosynthese von Riboflavin und Tetrahydrofolat ». [S.l. : s.n.], 2004. http://deposit.ddb.de/cgi-bin/dokserv?idn=973069473.
Texte intégralSchott, Anne-Kathrin. « Biochemische und strukturelle Charakterisierung von Enzymen der Riboflavin- und Folsäurebiosynthese ». [S.l. : s.n.], 2003. http://deposit.ddb.de/cgi-bin/dokserv?idn=969624212.
Texte intégralKim, Hyun Jung. « Oxidation mechanism of riboflavin destruction and antioxidant mechanism of tocotrienols ». Columbus, Ohio : Ohio State University, 2007. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1184681773.
Texte intégralCrossley, Rachel Amanda. « The role of riboflavin in the physiology of Campylobacter jejuni ». Thesis, University of East Anglia, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.426604.
Texte intégralHamilton, Jeffrey Hunt. « Photochemical Protection of Riboflavin and Tetrapyrroles with Light Scattering Technology ». Thesis, Virginia Tech, 2012. http://hdl.handle.net/10919/76811.
Texte intégralMaster of Science in Life Sciences
McAuley, Emma. « Riboflavin, MTHFR genotype and blood pressure : implications for personalised nutrition ». Thesis, Ulster University, 2016. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.706468.
Texte intégralGraham, Joanne Mimi. « Benefits of riboflavin plus iron supplementation for pregnant Nepali women / ». For electronic version search Digital dissertations database. Restricted to UC campuses. Access is free to UC campus dissertations, 2003. http://uclibs.org/PID/11984.
Texte intégralDegree granted in Nutrition. Dissertation completed in 2003; degree granted in 2004. Also available via the World Wide Web. (Restricted to UC campuses).
Hiltunen, Hanna-Maija. « Functional analysis of RIBA, the introductory enzyme for Riboflavin biosynthesis ». Doctoral thesis, Humboldt-Universität zu Berlin, Lebenswissenschaftliche Fakultät, 2016. http://dx.doi.org/10.18452/17525.
Texte intégralFlavin mononucleotide (FMN) and Flavin adenine dinucleotide (FAD) belong to the main redox coenzymes and are involved in central metabolic processes. They derive from riboflavin also referred to as vitamin B2. The bifunctional RIBA enzyme, which comprises peptide domains for GTP cyclohydrolase II (GCHII) and 3,4-dihydroxy-2-butanone-4-phosphate synthase (DHBPS) activity, performs the two initial steps of riboflavin biosynthesis in plants. Three genes encode RIBA proteins in Arabidopsis thaliana and many other flowering plants. One of the main aims of this study was to elucidate the physiological roles of the three RIBA isoforms. Detailed enzymatic studies were performed with recombinant RIBA proteins IN VITRO. It revealed for RIBA2 and RIBA3 the loss of either GCHII or DHBPS activity, respectively. The phosphorylation of RIBA1 as well as the inhibition of its GCHII activity by FMN could be demonstrated. A knockout of RIBA1, encoding the dominant RIBA isoform, led to embryo lethality. The gradual reduction of the RIBA1 protein content in Arabidopsis was associated with reduced flavin amounts and a severe bleaching phenotype that was caused by the gradual loss of pigments during leaf development. Flavin deficiency effects caused by RIBA1 depletion were characterised with a constitutive antisense mutant and the virus induced gene silencing method. A comprehensive metabolite profiling, revealed that the loss of almost one third of total flavin content led to a deregulation of several citric acid cycle-associated flavoenzymes. Moreover, a severe reduction of the catabolic capacity of numerous amino acids is seen, while seemingly flavin-dependent processes of the nitrogen assimilation are prioritised. In summary, this thesis contributes to the extended knowledge about the riboflavin biosynthesis pathway as well as to the understanding about consequences of flavin deficiency in plants. Moreover, the first attempt to increase the vitamin B2 content in plants is presented.
Chaves, Neto Antonio Hernandes. « Flavinas promovem mudanças na matriz extracelular, vias de transdução de sinal, enzimas antioxidantes e metaloproteinases durante a diferenciação de osteoblastos ». [s.n.], 2009. http://repositorio.unicamp.br/jspui/handle/REPOSIP/314035.
Texte intégralTese (doutorado) - Universidade Estadual de Campinas, Instituto de Biologia
Made available in DSpace on 2018-08-14T15:16:22Z (GMT). No. of bitstreams: 1 ChavesNeto_AntonioHernandes_D.pdf: 8240508 bytes, checksum: 293949f75ca619cdc0fa61d29d1703ba (MD5) Previous issue date: 2009
Resumo: Riboflavina (Rb - Vitamina B2) é o precursor das flavocoenzimas essenciais flavina mononucleotídeo (FMN) e flavina adenina dinucleotídeo (FAD). Estas coenzimas participam de processos enzimáticos dependentes das reações de transferências de elétrons, que ocorrem nas vias de produção de energia, biossíntese, desintoxicação e sequestro de elétrons. O aumento dietético da riboflavina e piridoxina foi associado com maiores densidades minerais em mulheres e homens idosos. Fotoderivados da riboflavina demonstraram efeitos citotóxicos em células cancerosas de próstata e leucemias, entretanto, o efeito direto da Rb e seus fotoderivados em osteoblastos não foram examinados. Neste trabalho os efeitos biológicos da Rb e riboflavina irradiada (IRb) foram investigados na linhagem de pré-osteoblastos MC3T3-E1, um modelo bem aceito de osteogênese in vitro caracterizado pela indução de genes específicos associados com o fenótipo osteoblástico quando tratados com ácido ascórbico e ß-glicerofosfato. A viabilidade celular foi avaliada através da redução do MTT, da incorporação do corante vermelho neutro e do conteúdo de ácidos nucléicos. Marcadores de diferenciação osteoblástica foram analisados através do RT-PCR semi-quantitativo (osteopontina e osteocalcina) e através de análises colorimétricas de atividade da fosfatase alcalina (FAL) e síntese de colágeno pela coloração de picrosirius. As atividades das metaloproteinases (MMP) -9 e -2 foram avaliadas pela zimografia de gelatina. Microarranjos de peptídeos com subtratos específicos para quinases e imunoblotting foram usados para identificar os efeitos na sinalização celular. As atividades de enzimas antioxidantes (superóxido dismutase, catalase, glutationa peroxidase e glutationa S-transferase) foram determinadas em lisados celulares usando métodos espectrofotométricos. As atividades das caspases-8, -9 e -3 foram analisadas através de métodos colorimétricos. Na primeira análise Rb e IRb causaram a parada do ciclo celular na fase G0/G1 e também a inibição da quinase AKT, um mediador da proliferação. Flavinas causaram a diferenciação de pré-osteoblastos, evidenciada pelo aumento da expressão de osteocalcina, osteopontina e BMP-2. Atividades mais elevadas de MMP-9 e MMP-2 também foram observadas. A capacidade das flavinas em engatilhar a diferenciação de osteoblastos foi reforçada pelo aumento da conexina 43, diminuição da caveolina-1 e repressão da sinalização Notch. Na segunda análise, nós encontramos que as interações entre Rb, em sua forma irradiada e não-irradiada, e indutores osteogênicos (ácido ascórbico e ß-glicerofosfato) afetaram significativamente a proliferação de osteoblastos, a atividade de FAL, biossíntese de colágeno, expressão de osteocalcina e osteopontina, a atividade das MMP-2 e MMP-9 e a expressão de fatores osteoclastogênicos (RANKL e osteoprotegerina). Nós também encontramos que os efeitos das flavinas em osteoblastos nesta segunda etapa foram independentes das suas propriedades antioxidantes. A atividade biológica da combinação de indutores osteogênicas com Rb e seus fotoprodutos foi associada com a ativação de diferentes vias de sinalização (AKT, FAK, CaMKII), caspases -8, -9 e -3 e aumento da expressão e/ou estabilização de fatores de transcrição osteoblásticos (Runx2 e ß-catenin). Este estudo nos trouxe fortes evidências que altas concentrações de Rb e IRb geraram um microambiente osteogênico através da modulação de diferentes vias de sinalização, além de promover um efeitos aditivo durante a diferenciação das células pré-osteoblasticas MC3T3 induzida por ácido ascórbico e ß- glicerofosfato. Em resumo, este estudo aponta para uma potencial aplicação da Rb e seus fotoprodutos no desenvolvimento do fenótipo osteoblástico e, consequentemente, uma alternativa terapêutica coadjuvante para osteoporose.
Abstract: Riboflavin (Rb-Vitamin B2) is the precursor of essential flavocoenzymes, flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD). These coenzymes participate in numerous enzymatic processes dependent on electron transfer reactions that occur in energyproducing, biosynthetic, and detoxifying and electron-scavenging pathways. Increase dietary riboflavin and pyridoxine intake has been associated with higher bone mineral density in elderly men and women. Photoderivatives of riboflavin have been shown strong activity in haematological malignancy and prostate cancer cells, however, the direct effect of Rb and its photoderivatives on osteoblast has not been examined. In this work, the biologic effects of Rb and irradiated riboflavin (IRb) were investigated in the MC3T3-E1 pre-osteoblastic cell line, a well-accepted model of osteogenesis in vitro characterized for the induction of specific genes associated with the osteoblastic phenotype when treated with ascorbic acid and ß-glycerophosphate. Cell viability was assessed by MTT reduction, neutral red uptake and nucleic acids content. Osteoblastic differentiation markers were analyzed by semiquantitative RT-PCR (osteopontin and osteocalcin), alkaline phosphatase (ALP) activity measured colorimetrically and collagen synthesis by Sirius red staining. Metalloproteinases (MMP) -9 and -2 activities were assayed by gelatin zymography. Peptide microarray of substrate specificity to kinases and immunoblotting were used to identify the effects on signal transduction pathways. Antioxidant enzyme activities (superoxide dismutase, catalase, glutathione peroxidase and glutathione Stransferase) were determined in cellular lysate using spectrophotometric methods. Caspase-8, -9 and -3 activation were measured by a colorimetric assay. In the first analysis Rb and IRb caused cell cycle arrest at G0/G1 phase and accordingly inhibited AKT kinase, a proliferation mediator. Flavins caused differentiation of preosteoblast cells as evidenced by increase of osteocalcin, osteopontin and BMP2 expressions. In addition, higher MMP-9 and -2 activities were observed. Importantly, the capacity of flavins to trigger osteoblasts differentiation was also reinforced by upregulation of connexin 43, down regulation of caveolin-1 and negative modulation of Notch cascade. In the second analysis, we found that the interaction between Rb and IRb and osteogenic inductors (ascorbic acid and ß-glycerophosphate) significantly affected the osteoblast proliferation, alkaline phosphatase activity, collagen biosynthesis, osteopontin and osteocalcin mRNA expression, MMP-2 and MMP-9 activities and the expression of osteoclastogenesis factors (RANKL and OPG). We also showed that the effects of flavins in osteoblasts cells were independent on flavins antioxidant property. The biological activity of the combination of osteogenic medium with riboflavin and its photoderivatives was associated with the activation of different signaling pathways (AKT, FAK, CaMKII), caspases -8, -9 and -3, and up-regulation and/or stabilization of osteoblastic transcription factors (Runx2 and ß-catenin). This study brought out strong evidences that high concentration of Rb and IRb generates an osteogenic microenvironment through modulating different mediators of signaling pathways, besides of the additive effect of riboflavin and its photoproducts during the ascorbate and ß-glycerophosphateinduced osteoblast differentiation of MC3T3-E1 cells. In summary, this study pointed out the potential application of Rb and its photoproducts in osteoblasts phenotype development and, consequently, it is possible use as an alternative therapeutic adjuvant of osteoporosis.
Doutorado
Bioquimica
Doutor em Biologia Funcional e Molecular
Reihl, Petra. « Untersuchungen zur Wahrnehmung und zur Aufnahme von Riboflavin in Saccharomyces cerevisiae ». [S.l.] : [s.n.], 2006. http://deposit.ddb.de/cgi-bin/dokserv?idn=981809855.
Texte intégralHuang, Rongmin. « Kinetics and effects of riboflavin photosensitized degradation on soymilk flavor stability ». Columbus, Ohio : Ohio State University, 2006. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1138713376.
Texte intégralGolbach, Jennifer L. « Development of a rapid riboflavin growth-based assay using Lactobacillus rhamnosus ». Texas A&M University, 2005. http://hdl.handle.net/1969.1/3131.
Texte intégralLideberg, Josefine. « Keratitbehandling, antibiotika versus corneal collagen crosslinking (CXL) genom riboflavin och UVA ». Thesis, Linnéuniversitetet, Institutionen för naturvetenskap, NV, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-19711.
Texte intégralPatterson, Beverley Elaine. « Metabolic studies of riboflavin deficiency in the rat and premature infant ». Thesis, University of Cambridge, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.329292.
Texte intégralMohnicke, Mandy [Verfasser]. « On the control of riboflavin (vitamin B2) crystal structures / Mandy Mohnicke ». Aachen : Shaker, 2007. http://d-nb.info/1166508757/34.
Texte intégralAmir, Fatima E. « The Clinical Journey of Patients with Riboflavin Transporter Deficiency Type 2 ». University of Cincinnati / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1522312243772827.
Texte intégralBeena, T. K. « Antigenic Determinants Of Chicken Riboflavin Carrier Protein : Structural And Functional Aspects ». Thesis, Indian Institute of Science, 1994. https://etd.iisc.ac.in/handle/2005/141.
Texte intégralBeena, T. K. « Antigenic Determinants Of Chicken Riboflavin Carrier Protein : Structural And Functional Aspects ». Thesis, Indian Institute of Science, 1994. http://hdl.handle.net/2005/141.
Texte intégralSilvério, Carolina Castelli [UNIFESP]. « Deglutição de parkinsonianos pré e pós riboflavina : queixa, aspectos funcionais e impacto na vida diária ». Universidade Federal de São Paulo (UNIFESP), 2009. http://repositorio.unifesp.br/handle/11600/9297.
Texte intégralObjetivo: verificar a relação entre queixa, aspectos funcionais da deglutição e impacto na qualidade de vida referente à voz e à deglutição, em pacientes portadores da doença de Parkinson, submetidos à administração de riboflavina, no período de um ano. Métodos: participaram do estudo 16 pacientes portadores da Doença de Parkinson, com média de idade de 67,25 anos, média do nível de severidade da doença de II para III e média de tempo de diagnóstico da doença de Parkinson de 3,5 anos. As avaliações videofluoroscópicas da deglutição foram realizadas antes e após um ano da administração de riboflavina e restrição de carne vermelha e de aves. Foram realizadas a análise qualitativa da deglutição, a verificação da presença de queixa com relação à deglutição e aplicação de dois protocolos de qualidade de vida sendo relacionados um com o impacto da alteração vocal, e outro com o impacto da alteração na deglutição. A análise quantitativa compreendeu a realização de medidas de deslocamento do osso hióide, de abertura do esfíncter esofágico superior e de constrição da faringe. Resultados: foram observadas redução da queixa e discreta piora na qualidade de vida relacionada à voz e à deglutição, maior freqüência de ocorrência de deglutição normal, no momento pós-riboflavina. Não foram observadas diferenças significativas entre as medidas quantitativas. Conclusões: Conclui-se neste estudo que: houve melhora, apesar de não significativa, da queixa relacionada à deglutição; não ocorreram pioras significativas na dinâmica da deglutição, com exceção do deslocamento da cartilagem cricóidea na consistência de líquido fino após um ano de estudo; não houve piora com relação ao impacto na qualidade de vida, tanto relacionado à deglutição, quanto ao aspecto vocal; os pacientes que não apresentavam queixas de deglutição no momento pré apresentaram melhora na dinâmica da deglutição, com exceção da constrição da faringe; os pacientes com queixa de deglutição no momento pré apresentaram melhora nos índices de qualidade de vida e na auto-avaliação vocal segundo o QVV, no momento pós.
Objective: to verify the relation between clinical complaint, swallowing functional aspects and the impact on quality of life related to voice and swallowing in patients with Parkinson´s disease submitted to treatment with riboflavin during one year period. Method: sixteen patients with Parkinson´s disease participated in the study; mean age was 67.25 years old, mean degree of disease severity was II to III and mean time of disease diagnosis was 3.5 years. Videofluoroscopic evaluations were performed before and after one year of treatment with riboflavin and restriction diet of read meat and chicken. It were analyzed: qualitative analysis of swallowing, presence of complaints related to swallowing, application of questionnaires related to the impact of voice and swallowing alterations and quantitative analyses of swallowing, which included computerized measurements of hyoid bone and cricoid cartilage displacement, opening of the superior esophageal sphincter and pharyngeal constriction. Results: it were observed: decrease of complaints and slight worsening in quality of life impact regarding voice and swallowing and more frequent normal swallowing post riboflavin; there were no significant changes regarding quantitative measurements. Conclusions: there was a non significant improvement regarding swallowing complaints; it were not observed significant impairments of the swallowing dynamics, except for cricoid cartilage displacement during thin liquid ingestion at the end of the treatment; there was no impairment of quality of life regarding swallowing or voice; patients without swallowing complaints at the beginning of the treatment showed improvement in swallowing dynamics, except for pharyngeal constriction; patients with swallowing complaints at the beginning of the treatment showed improvement regarding quality of life and vocal selfevaluation after treatment.
TEDE
BV UNIFESP: Teses e dissertações
Shi, Xiaofeng. « Time-Resolved Spectroscopic Studies of the Photochemistry of riboflavin, aromatic N-Oxides and the absolute reactivity of hydroxyl radical ». The Ohio State University, 2005. http://rave.ohiolink.edu/etdc/view?acc_num=osu1126795561.
Texte intégralHucker, Barry. « The presence and role of Thiamine and Riboflavin in the malting and brewing industries ». Thesis, University of Ballarat, 2013. http://researchonline.federation.edu.au/vital/access/HandleResolver/1959.17/58647.
Texte intégralDoctor of Philosophy
Körber, Nicole. « Ein neuer therapeutischer Ansatz zur vorbeugenden Behandlung der pathologischen Myopie - Einfluss des skleralen Riboflavin/Blaulicht Cross-Linkings auf das Augenwachstum junger Kaninchen ». Doctoral thesis, Universitätsbibliothek Leipzig, 2017. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-220353.
Texte intégral