The FRIABLE1 (FRB1) gene is identified to be a novel glycosyltransferase involved in cell adhesion, based on reverse genetics and immunocytochemistry studies. A total of 31 FRB1 paralogues were found in Arabidopsis thaliana using a bioinformatics approach. The following expression analysis has revealed 6 FRB1 paralogues to be pollen-specific. One pollen-specific FRB1 paralogue, At1g14970, exhibits longer silique lengths when exposed to higher than normal temperature at 28oC in its T-DNA insertional knockout when compared to Columbia wildtype plants. This may be due to the loss of temperature sensing and the continuous stimulated pollen tube cell wall growth or the up-regulation of genes that encode other glycosyltransferases. Thus, the identification of FRB1 paralogues and homologues in both rice and poplar may have tremendous potential to increase their yield in global warming for agricultural and industrial benefits.

Combined intakes of specific dietary fiber and fat subtypes protect against colon cancer in animal models. We evaluated associations between self-reported individual and combinations of fiber (insoluble, soluble, and pectins, specifically) and fat (omega-6, omega-3, and docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), specifically) and colorectal cancer (CRC) risk in the Women's Health Initiative prospective cohort (n = 134,017). During a mean 11.7 years (1993-2010), 1952 incident CRC cases were identified. Cox regression models computed multivariate adjusted hazard ratios to estimate the association between dietary factors and CRC risk. Assessing fiber and fat individually, there was a modest trend for lower CRC risk with increasing intakes of total and insoluble fiber (p-trend 0.09 and 0.08). An interaction (p = 0.01) was observed between soluble fiber and DHA + EPA, with protective effects of DHA + EPA with lower intakes of soluble fiber and an attenuation at higher intakes, however this association was no longer significant after correction for multiple testing. These results suggest a modest protective effect of higher fiber intake on CRC risk, but not in combination with dietary fat subtypes. Given the robust results in preclinical models and mixed results in observational studies, controlled dietary interventions with standardized intakes are needed to better understand the interaction of specific fat and fiber subtypes on colon biology and ultimately CRC susceptibility in humans.

Os sistemas de liberação de fármacos são parte integrante da investigação farmacêutica. Grande ênfase tem sido dada à utilização de polímeros hidrofílicos naturais como carreadores devido às vantagens inerentes a seu baixo custo, biocompatibilidade e segurança de uso. Os objetivos principais deste trabalho foram a preparação e avaliação de sistemas microparticulados a base de pectina e caseína e o estudo da liberação in vitro do aciclovir contido nas micropartículas. Esses sistemas visam uma liberação prolongada do fármaco aumentando sua biodisponibilidade oral. O efeito de parâmetros como pH, força iônica, viscosidade, proporção e concentração total de polímeros foi avaliado. A melhor condição para ocorrência da coacervação foi determinada por mobilidade eletroforética, rendimento do coacervado e microscopia ótica. A pectina e a caseína podem interagir formando complexos insolúveis. A formação do complexo coacervado foi espontânea e ocorreu em condições brandas no intervalo de pH em que os polímeros encontram-se carregados com cargas opostas. As dispersões foram secas em Spray dryer, resultando em partículas bastante pequenas (6µm) e homogêneas. Através da microscopia ótica foi possível observar que o fármaco se encontrava no interior das micropartículas. O pH (4,0-5,0) do meio influenciou decididamente a formação dos complexos coacervados, e a melhor relação mássica para o par pectina/caseína foi 1:1. Proporções superiores ou inferiores reduziram significativamente a extensão da coacervação. O aumento no teor de sólidos totais (4-8% p/v) bem como a adição de sal (0-120 mMol) não suprimiu a formação ou a estabilidade do sistema. Foram preparadas matrizes hidrofílicas contendo as micropartículas encapsuladas com aciclovir. O estudo de dissolução in vitro demonstrou que a liberação do aciclovir foi mais lenta nos sistemas matriciais e microparticulados do que a do fármaco livre. Entretanto, as matrizes apresentaram perfis de liberação sustentada mais adequados do que os sistemas microparticulados. / Drug delivery systems became an integral part of pharmaceutical research. The use of natural hydrophilic polymers as drug carriers has received considerable attention in the last few years, especially from the viewpoint of cost, environmental concerns and safety. The main purpose of this study was to report and discuss the preparation of a microparticulate system by mixing the negatively charged pectin and the amphoteric casein and also the in vitro evaluation of polymeric microparticulate systems loaded with acyclovir. Such drug delivery system was conceived to prolong the therapeutic activity of acyclovir and increase its oral biovailability.The influence of pH, total biopolymers concentration, viscosity of dispersions, pectin/casein ratio and ionic strength were reported. Zeta potential measurements and dry coacervate yield were used to determine the optimal conditions for complex coacervation and were supplemented by optical microscopy. Pectin/casein in aqueous mixture may interact and form insoluble complexes. The complex formation was spontaneous and occurs under mild conditions. The phenomenon of complex coacervation mainly occurs at a pH range when both polyelectrolytes carry opposite charges. Microparticulate preparations were spray dried and results showed that the microparticles obtained were always quite small, the diameters of 80% of the particles did not exceed 6m, and physicochemical characterization showed that the drug was homogeneously dispersed inside the microparticles. Pectin/casein ratio and pH range were found to mainly affect the microparticles formation and encapsulation efficiency. The complex coacervation was dependent on pH (4,0-5,0) and the optimum pectin/casein ratio was 1:1. Superior or inferior proportion significantly decreased the coacervate yield. Increasing in total biopolymer concentration (4-8% w/v) and salt addition (0-120 mMol) did not inhibit the formation and stability of pectin/casein systems. Hydrophilic matrices containing acyclovir loaded microparticles were also prepared. The in vitro dissolution profile of acyclovir from the microparticulate systems and matrices were slower than that for the free drug. However, the sustained release characteristic was more prominent in matrices than in microparticles formulations

Misturas aquosas de polissacarídeos e proteínas são normalmente instáveis e separam-se em fases devido às interações repulsivas ou atrativas existentes entre os polímeros. O efeito da temperatura, do pH e da concentração polimérica no comportamento de misturas de pectina/caseína foi estudado nesse trabalho. Um diagrama de fases construído em pH 7 revelou que a mistura é estável apenas em baixas concentrações. Concentrações mais elevadas levam à incompatibilidade termodinâmica, governada por forças puramente entrópicas, e ao aparecimento de duas fases: uma rica em caseína (inferior) e outra rica em pectina (superior). A decomposição espinodal pôde ser visualizada nos estágios iniciais da separação de fases e, nos estágios intermediários, observou-se a formação de emulsões água/água. Quando o pH dessas emulsões é reduzido para abaixo de 6, a pectina é atraída para a fase de caseína, resultando na formação de partículas de complexo pectina/caseína que não coalescem e são resistentes à adição de sal (NaCl 100 mM), apresentando um diâmetro médio aproximado de 4 m. As micropartículas de pectina/caseína produzidas por este método demonstraram ser capazes de encapsular com alta eficiência tanto substâncias hidrofóbicas quanto hidrofílicas, possibilitando sua aplicação na encapsulação de compostos variados para fins diversos. Neste trabalho, as micropartículas foram utilizadas para encapsular cristais de metronidazol e sua utilização na obtenção de filmes de aplicação intra-bolsa periodontal foi avaliada in vitro. As dispersões de pectina/caseína contendo as micropartículas carregadas foram submetidas à secagem para a obtenção dos filmes. Estes, reticulados ou não com cálcio, sustentaram a liberação in vitro do fármaco por pelo menos 7 dias in vitro. A reticulação foi importante para reduzir a desintegração dos filmes, contribuindo para aumentar o tempo de permanência deles no local de aplicação e para melhorar suas propriedades mecânicas, facilitando seu manuseio e inserção na bolsa periodontal. Com esses resultados, conclui-se que os filmes de micropartículas de complexo pectina/caseína contendo metronidazol desenvolvidos neste trabalho são excelentes candidatos a sistemas de liberação local para o tratamento da doença periodontal. / Aqueous mixtures of polysaccharides and proteins are usually unstable and phase-separate either because of repulsive or attractive interactions. The effect of temperature, pH, and biopolymer concentration on the phase behavior of pectin/casein mixtures was investigated. A phase diagram built at pH 7 revealed that the mixture is stable at low polymer concentrations. Higher concentrations lead to thermodynamic incompatibility, driven purely by entropic forces, and to the appearance of two phases: one enriched with casein (lower) and the other, with pectin (upper). Spinodal decomposition was visualized in the early stages of phase separation. In the intermediate stages, water-in-water emulsions were observed. When the pH of these emulsions was lowered below 6, pectin was attracted by casein-rich phase, resulting in the formation of particles (diameter ~ 4 m) of pectin/casein complex, which do not coalesce and are insensitive to salt addition (100 mM NaCl). Pectin/casein microparticles obtained by this method were able to encapsulate with high efficiency either hydrophobic or hydrophilic substances and, due to that, could be applied in the encapsulation of a great variety of compounds for different purposes. In this work, the pectin/casein microparticles were used to encapsulate metronidazole crystals and the preparation of intra-periodontal pocket films with them was evaluated. Therefore, dispersions of loaded pectin/casein microparticles were dried in an oven. Films cross-linked or not with calcium sustained the in vitro drug release at least for 7 days. The cross-linking with calcium was important to reduce film disintegration, accounting for its permanence in the applied region, and to improve the mechanical properties, which facilitates manipulation and insertion into the periodontal pocket. With these results we conclude that the films formed by microparticles of pectin/casein complex loaded with metronidazole are excellent candidates for local drug delivery systems for the treatment of periodontal disease.

Esta dissertação apresenta a preparação e caracterização de eletrólitos poliméricos géis (EPGs) a partir de pectina comercial GENU®, plastificada com glicerol e dopada com perclorato de lítio. O objetivo é a utilização de uma nova matéria-prima para a obtenção de eletrólitos poliméricos substituindo os polímeros sintéticos. A pectina é um polímero natural presente nas plantas; quimicamente é um polímero heterogêneo, e estruturalmente, é constituída unidades repetidas de (1→4)-α-D-ácido galacturônico. Os eletrólitos foram preparados usando como sal LiClO4 (0,24 g ou 30 [O]/[Li]), e 0,6 g de pectina com diferentes quantidades de glicerol (0 g - 2,0 g; 0% - 70%) como plastificante. Os filmes foram caracterizados por espectroscopia de impedância, difração de raios-X, UV-Vis, FT-IR, análises térmicas (DSC e TG). Os melhores resultados foram apresentados pelos filmes constituídos com 70% de glicerol e 30 [O]/[Li] e 68% de glicerol e 0,24 g de LiClO4. .Os filmes com 68% de glicerol apresentam valores de condutividade iônica de 1,61x10-4 S.cm-1 em temperatura ambiente aumentando para 1,72x10-3 S.cm-1 à 80°C, e uma transmitância de 80% no intervalo do visível. Os valores da energia de ativação para este filme é em torno de 37 KJmol-1. Também foi verificada a estabilidade eletroquímica em uma faixa de potencial que varia entre -1,5 a +1,5V. Os filmes com 70% de glicerol apresentam os melhores valores de condutividade iônica de 3,08x10-4 S.cm-1 em temperatura ambiente para 2,94x10-3 S.cm-1 à 80°C, e energia de ativação em torno de 35 KJmol-1, e transmitância de 75% no intervalo do visível. Os resultados obtidos indicaram que os eletrólitos a base de pectina são promissores para aplicações em dispositivos opto-eletroquimicos. / This work presents the preparation and characterization of pectin GENU®-based gel polymeric electrolytes (GPEs), plasticized with glycerol and doped with lithium perchlorate. The use of a new raw material for the production of polymeric electrolytes, as substitutes of synthetic polymers is the proposal of this work. Pectin is a natural polymer found in plants. This polymer is chemically heterogeneous and structurally, are composed of a main linear chain of (1→4)-α-D-galacturonic acid. The electrolytes were prepared using salt as LiClO4 (0.24 g or 30 [O]/[Li]) to 0.6 g of pectin and with different amounts of glycerol (0-2.0g, 0-70%) as plasticizer. The films were characterized by impedance spectroscopy, X-ray diffraction, UV-Vis, FT-IR, thermal analysis (DSC and TG). The best results were obtained with films containing 70% of glycerol and 30 [O]/[Li] and 68% of glycerol and 0.24 g LiClO4. The films with 68% of glycerol exhibit ionic conductivity values of 1.61 x10-4 S.cm-1 at room temperature with increase to1.72 x10-3 S.cm-1 at 80°C, and showed a transmittance of 80% in the visible range. The values of activation energy for this sample is around 37 kJmol-1. It was also observed the electrochemical stability in the potential range of -1.5 to +1.5 V. The films with 70% of glycerol showed best ionic conductivity values of 3.08 x10-4 S.cm-1 at room temperature wich increase to 2.94 x10-3 S.cm-1 at 80°C, and activation energy around 35 kJmol-1, and a transmittance of 75% in the visible range. All the obtained results show pectin-based polymer electrolytes over promising materials to be used in opto-electrochemical devices.

In this work an investigation to find new method of extraction of pectin from orange peel with shortening time of extraction is carried out. Pectin was extracted from dried orange peel at higher temperature by employing stainless steel reactors. In this investigation the effect of extraction conditions (temperature: 120, 150, 200°C; extraction time: 5, 15, 30 min) with sulphuric acid, on the yield and purity of citrus pectin was performed. Moreover, optimizing other methods of extraction and analyzing of pectin is tested. In addition, effect of adding special reagent such as Sodium polyphosphate to extract solvent examined. Furthermore, two different acids are used for extraction and the results are compared as described. Pectin is solubilized by HCl and H2SO4 at different concentrations, retention time and temperature. The effect of extraction conditions (pH: 1.5 to 2; temperature: 80 to 90°C; extraction time: 1 to 3 hours) with sulphuric acid, on the yield and purity of citrus pectin was carried out. The solubilized pectin is precipitated from the solution by using organic solvents such as 2-propanol and ethanol and then analysis was done with different methods such as carbozole and meta-hydroxy-diphenyl method. A same test was run for hydrochloric acid and comparison between them was done. / Uppsatsnivå: D

No description available.

Starch residue samples from two Australian sweet potato varieties (Beauregard and Northern Star) and two Indonesian sweet potato varieties (Bis192 and Bis183), and commercial sample of sweet potato starch residue, were studied for their pectins. Pectins were extracted using 0.1M HCl, 0.05M NaOH, 0.1M HCl/0.75%SHMP, and 0.05M NaOH/0.75% SHMP. Hydrolysis of residual starch in the cell wall of sweet potato using heat stable α-amylase and amyloglucosidase was employed prior to pectin extraction to eliminate starch contamination. Pectins were characterised for yield, moisture, ash, galacturonic acid content (GA), degree of esterification (DE), neutral sugars content and molecular weight (MW). Selected pectins were also characterised for their dispersion and gel properties. Pectin with the highest yield was compared to commercial low methoxyl pectin (GRINSTED??YF 450) for its application in milk pudding. The pectin characteristics are dependent on variety and extraction process; however, the extraction methods were dominant. Yields were between 7 and 30 % of the cell wall. Ash varied from 2.9 to 6.8%. NaOH/SHMP extraction gave higher yields and ash contents. Moisture was between 5.5 and 6.7. GA varied from 27 to 80% with the highest found in Bis192 extracted using NaOH/SHMP. DE varied between traceable and 57%. HCl extraction gave higher DE, while NaOH/SHMP caused demethylation. Neutral sugars varied from 10 to 25% where galactose was the predominant sugar, followed by arabinose, rhamnose, glucose and xylose. Pectin MW was very heterogeneous. HCl extraction gave higher MW than the others. Dispersion of sweet potato pectins displayed shear-thinning. Consistency coefficient (K) increased, while flow behaviour index (n) decreased with increasing pectin concentration. HCl-extracted pectins formed stiff sugar-gels at concentrations higher than 2%. The optimum Ca2+ concentration for NaOH/SHMP-extracted pectin gels was 20 mg/g pectin. Pectin with the highest yield and stiffness (Norther Star extracted using NaOH containing SHMP) was used for milk pudding preparation. This pudding had comparable texture to pudding prepared from commercial low methoxyl citrus pectin (GRINSTED??YF 450). Overall, this study demonstrated that pectin from sweet potato starch residue is mainly low methoxyl pectin with possible chemical structure of rhamnogalacturonan I (RGI) that has potential for food applications.

Thesis (Ph.D.) -- University of Glasgow, 2007. / PhD thesis submitted to Environmental, Agricultural and Analytical Chemistry, Department of Chemistry, University of Glasgow. Includes bibliographical references. Print version also available.

Thesis (Ph. D.)--University of Missouri-Columbia, 2000. / Typescript. Vita. Includes bibliographical references. Also available on the Internet.