Submitted by (lucia.rodrigues@ufrpe.br) on 2017-03-23T13:42:02Z No. of bitstreams: 1 Robson Jose do Nascimento.pdf: 504518 bytes, checksum: c6daea872bbe37b1f317f4658b6ff1ab (MD5) / Made available in DSpace on 2017-03-23T13:42:02Z (GMT). No. of bitstreams: 1 Robson Jose do Nascimento.pdf: 504518 bytes, checksum: c6daea872bbe37b1f317f4658b6ff1ab (MD5) Previous issue date: 2006-02-21 / Garlic is a monocotyledon belonging to the family Aliaceae, originating in Central Asia. In Brazil, it was introduced by the Portuguese, at the time of discovery, being widely used in cooking until the present day. Botanically, it is an agrarian herbaceous, with approximately 50 cm of height, propagated by bulbilho, which allows the maintenance of the agronomic characteristics. This method of propagation allows an efficient dissemination of pathogens, mainly viruses, which are one of the main groups of pathogens of this culture, which can cause a reduction of productive potential between 20 and 80%. Garlic is a natural host of viral species belonging to the genera Potyvirus, Carlavirus and Allexivirus. The latter was recently established as a member of the Flexiviridae family and groups Garlic mite-borne filamentous virus (GarMbFV), Garlic virus A (GarV-A), Garlic virus B (GarV-B), Garlic virus C Garlic virus D (GarV-D), Garlic virus E (GarV-E), Garlic virus X (GarV-X) and Shallot virus X (ShV-X). In Brazil, imported garlic has been used for planting, which constitutes a risk of introduction of exotic viral species in the country. Currently, the detection of allexivirus in bulbs can be performed by serological and / or molecular tests, and planting is necessary to obtain foliar tissue with high concentration of viral particles, which requires, on average, 30 days. Serological tests are efficient, however, because of the difficulty in producing high quality antisera, are currently less indicated than molecular methods. Aiming to reduce the time for analysis of detection of allexivirus in garlic, a methodological adjustment for nucleic acid extraction was sought directly from the leaf primordia of bulbilhos. Samples of garlic, from Rio Grande do Sul and imported from Argentina were analyzed using foliar primordia obtained by dissecting the bulbiles to extract total RNA using the Trizol reagent. Amplifications of the target genomic fragment were performed via RT-PCR. A band at the time corresponding to 500 bp was observed on agarose gel in the two samples studied. PCR products were transferred to membranes for Southern blot testing, for which a cold probe capable of detecting Allexivirus species was used, from which testing the presence of allexivirus was confirmed. Another allexivirus detection analysis was carried out on samples of garlic consumption imported from Argentina, China and Spain, following the same methodology, being verified a band corresponding to 500 bp in samples from Argentina and China. Southern Blot test, in which a specific cold probe was used to detect GarV-C, confirmed viral infection by the aforementioned species. According to the results obtained, it was found that the extraction of total RNA directly from leaf primordia, combined with the use of molecular techniques, presents itself as a fast and efficient method for detection of allexivirus. It was also verified that most of the analyzed samples are infected with allexivirus, evidencing a sanitary pattern that contraindicates the use of this type of material as seed, with the risk of introduction of exotic viral species. / O alho é uma monocotiledônea pertencente à família Aliaceae, originário da Ásia Central. No Brasil, foi introduzido pelos portugueses, na época do descobrimento, sendo amplamente utilizado na culinária até os dias atuais. Botanicamente, trata-se de uma herbácea agâmica, com aproximadamente 50 cm de altura, propagada via bulbilho, o que permite a manutenção das características agronômicas. Este método de propagação possibilita uma eficiente disseminação de patógenos, principalmente vírus, que são um dos principais grupos de patógenos desta cultura, podendo causar uma redução do potencial produtivo entre 20 e 80%. O alho é hospedeiro natural de espécies virais pertencentes aos gêneros Potyvirus, Carlavirus e Allexivirus. Este último foi recentemente estabelecido como membro da família Flexiviridae e agrupa as espécies Garlic mite-borne filamentousvirus (GarMbFV), Garlic virus A (GarV-A), Garlic virus B (GarV-B), Garlic virus C (GarV-C), Garlic virus D (GarV-D), Garlic virus E (GarV-E), Garlic virus X (GarV-X) e Shallot virus X (ShV-X). No Brasil, o alho consumo importado tem sido empregado para o plantio, o que se constitui um risco de introdução de espécies virais exóticas no país. Atualmente, a detecção de allexivírus em bulbos pode ser realizada por testes sorológicos e/ou moleculares, sendo necessário plantio para obtenção de tecido foliar com alta concentração de partículas virais, o que requer, em média, 30 dias. Os testes sorológicos são eficientes, no entanto, em razão da dificuldade para produção de anti-soros de alta qualidade, atualmente são menos indicados que os métodos moleculares. Objetivando reduzir o tempo para análise de detecção de allexivírus em alho, buscou-se um ajustemetodológico para extração de ácido nucléico diretamente dos primórdios foliares de bulbilhos. Amostras de alho consumo, oriundos do Rio Grande do Sul e importado daArgentina foram analisadas, empregando-se primórdios foliares obtidos por dissecação dos bulbilhos para extração de RNA total com uso do reagente Trizol. As amplificações do fragmento genômico alvo foram realizadas via RT-PCR. Uma banda na altura correspondente a 500 pb foi observada, em gel de agarose, nas duas amostras estudadas. Os produtos de PCR foram transferidos para membranas para teste de Southern Blot, para o qual empregou-se uma sonda fria capaz de detectar espécies de Allexivirus, de cujo teste foi confirmado a presença de allexivírus. Outra análise de detecção de allexivírus foi realizada em amostras de alho consumo importado da Argentina, China e Espanha, seguindo a mesma metodologia, sendo verificada, uma banda na altura correspondente a 500 pb em amostras oriundas da Argentina e da China. Teste de Southern Blot, no qual empregou-se uma sonda fria específica para detectar GarV-C, confirmou infecção viral pela espécie citada. De acordo com os resultados obtidos constatou-se que a extração de RNA total diretamente de primórdios foliares, aliada ao uso de técnicas moleculares apresenta-se como um método rápido e eficiente para detecção de allexivírus. Constatou-se também, que a maior parte das amostras analisadas encontra-se infectada por allexivírus, evidenciando um padrão sanitário que contra-indica o uso deste tipo de material como semente, com o risco de introdução de espécies virais exóticas.

Submitted by Mario BC (mario@bc.ufrpe.br) on 2018-11-14T12:21:52Z No. of bitstreams: 1 Sirleide Maria de Menezes.pdf: 1658917 bytes, checksum: 9afadd73ca19e451b3c75a436ba51168 (MD5) / Made available in DSpace on 2018-11-14T12:21:52Z (GMT). No. of bitstreams: 1 Sirleide Maria de Menezes.pdf: 1658917 bytes, checksum: 9afadd73ca19e451b3c75a436ba51168 (MD5) Previous issue date: 2018-07-24 / Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPq / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / The pulse irrigation appears to give support for handling and promote increases in the quantity and quality of the products. This technique has presented resulted significantly with respect to the water economy, however, little is known on its relation to the mineral nutrition of the plants. Coriander (Coriandrum sativum L.) is an important vegetable in the socioeconomic scenario of the country, there is little information about mineral nutrition and cropping systems. The objective of this study was to evaluate the effect of pulsed and continuous drip irrigation on nutritional status and accumulation of dry matter and nutrients by coriander. The experiment was conducted from August to September 2017, in a protected environment in the Agronomy Department of the Universidade Federal Rural of Pernambuco - Recife, PE, Brazil. The design was a randomized complete block design in a 2 x 5 factorial schemes with three replications. The treatments were composed of two types of fertigation application (pulsed and continuous fertigation) and five fertigation replacement blades (40, 60, 80, 100 and 120% of the crop evapotranspiration - ETc). For the pulsed fertigation, six pulses with a 60-minute rest interval between two applications were defined. Pulsed fertigation combined with ETc replacement blades lower than 100% provided higher P, S, Fe and Mn leaf contents. Continuous fertigation with the 100% ETc blade induced sulfur deficiency in the crop and, combined with 40% blade provided the highest Ca content. ETc replacement blades from 82.7 and 40%, regardless of the type of application, provide nitrogen and magnesium foliar contents, respectively. Continuous fertigation reduced potassium leaf content and pulsed magnesium contents, but not to the point of causing nutritional disorder. The ETc replacement blades positively influenced the accumulation of dry matter and of all nutrients (N, P, K, Ca, Mg, S, Fe, Mn, Cu and Zn) studied. Pulsed fertigation promoted the highest accumulations of dry mass, N, P, K, Fe, Mn, Cu and Zn, and reduced the accumulation of Ca by the crop. The highest accumulations of K, Mn, Cu and Zn were obtained with the application of pulsed Fertigation combined with ETc replacement blades lower than 100%. The accumulation of nutrients by the crop in both types of fertigation application decreased in the following order: K> N> Ca> P> Mg> S> Fe> Mn> Zn> Cu. / A irrigação por pulsos, surge para dar suporte ao manejo de irrigação e promover incrementos na quantidade e qualidade dos produtos. Essa técnica tem apresentado resultados significativos no que diz respeito à economia de água, no entanto, pouco se sabe sobre sua relação com a nutrição mineral das plantas. Sendo o coentro (Coriandrum sativum L.) uma hortaliça importante no cenário socioeconômico do país, poucas são as informações acerca da nutrição mineral e sistemas de cultivo. Deste modo, objetivou-se avaliar o efeito de lâminas de fertirrigação por gotejamento pulsado e contínuo sobre o estado nutricional e acúmulo de massa seca e de nutrientes pela cultura do coentro. O experimento foi conduzido no período de agosto a setembro de 2017, em ambiente protegido no Departamento de Agronomia da Universidade Federal Rural de Pernambuco, Recife, PE, Brasil. O delineamento foi em blocos casualizados em esquema fatorial 2 x 5, com três repetições. Os tratamentos foram compostos por dois tipos de aplicação de fertirrigação (fertirrigação pulsada e contínua) e cinco lâminas de reposição da fertirrigação (40, 60, 80, 100 e 120% da evapotranspiração da cultura-ETc). Para a fertirrigação pulsada foram definidos seis pulsos com intervalo de 60 minutos de repouso entre duas aplicações. A fertirrigação pulsada combinada com lâminas de reposição da ETc inferiores a 100% proporcionaram maiores teores foliares de P, S, Fe e Mn. A fertirrigação contínua com a lâmina de 100% da ETc induziu deficiência de enxofre na cultura e, combinada com a lâmina de 40% proporcionou o maior teor de Ca. Lâminas de reposição da ETc a partir de 82,7 e de 40%, independentemente do tipo de aplicação, proporcionam teores foliares, respectivamente, de nitrogênio e de magnésio considerados adequados. A fertirrigação contínua reduziu os teores foliares de potássio e, a pulsada os teores de magnésio, mas não a ponto de causar desordem nutricional. As lâminas de reposição da ETc influenciaram positivamente o acúmulo de massa seca e de todos os nutrientes (N, P, K, Ca, Mg, S, Fe, Mn, Cu e Zn) estudados. A fertirrigação pulsada promoveu os maiores acúmulos de massa seca, N, P, K, Fe, Mn, Cu e Zn, e reduziu o acúmulo de Ca pela cultura. Os maiores acúmulos de K, Mn, Cu e Zn foram obtidos com a aplicação da fertirrigação pulsada combinada com lâminas de reposição da ETc inferiores a 100%. O acúmulo de nutrientes pela cultura do coentro em ambos os tipos de aplicação de fertirrigação decresceu na seguinte ordem: K > N > Ca > P > Mg > S >Fe > Mn > Zn > Cu.

Con el propósito de conocer el comporta miento y rentabilidad del cultivo de ajo bajo riego por goteo, se realizó una evaluación técnica y económica de cuatro configuraciones de riego por goteo. El ensayo se realizó en un predio ubicado en la ciudad de Llay-llay perteneciente a la provincia de San Felipe, V Región. El cultivo se desarrolló entre los meses de mayo y noviembre del 2003. Las cuatro configuraciones de riego por goteo se distribuyeron en un diseño experimental completamente al azar con 8 repeticiones. La unidad experimental consistió en una mesa de cultivo de 1,47 m de ancho por 50 m de largo. Los tratamientos consintieron en instalación de dos o tres tuberías de goteo por cama sobre el suelo o enterradas a 20 cm. Para la evaluación técnica se midieron parámetros de crecimiento como diámetro ecuatorial del bulbo y producción de materia seca. Además se midieron variables de rendimiento como la producción de bulbos cosechados y la distribución de tamaño de éstos. En cuanto a la evaluación económica, cada configuración de riego se planteó como un sistema de riego, determinado los costos qu e implicaría la instalación de estos sistemas en la realidad. Para determinar la configurac ión más rentable se utilizaron indicadores de rentabilidad como el valor actual neto, tasa interna de retorno, relación beneficio costo y periodo de recuperación de la inversión. Además, se realiz ó un análisis de sensibilidad. Desde el punto de vista técnico no se observaron diferencias estadísticamente significativas entre los tratamientos a excepción de la acumulación de la materia seca total. Las variaciones observadas podrían ser explicadas por las diferentes precipitaciones que entregaban los tratamientos. Tres tuberías de goteo en superficie generan un frente de mojamiento lateralmente homogéneo pero llega a menor profundidad. En tanto los tratamientos con dos tuberías de goteo por tener un mayor tiempo de riego logran una mayor lámina aplicada en el punto de goteo, llegando a profundidades adecuadas. El rendimiento promedio obtenido fue de 15,8 ton ha -1 , del cual un 79% corresponde a ajo con calidad de exportación; todos los tratamientos presentaron igual distribución de calibres. Al evaluar económicamente los tratamientos el mejor evaluado fue el de dos tuberías de goteo por cama, enterradas a 20 cm. En este se maximizaron los recursos, ya que utilizó menos tuberías por cama y al estar enterradas no sería necesario su recambio a la mitad del proyecto por deterioro. Al realizar un análisis de sensibilidad se observó que los proyectos son más sensibles a la baja de lo s precios de venta, que al alza de insumos.

Allium sativum and Tulbaghia violacea are some of the most important medicinal plants used by South African traditional healers for the treatment of flu, fever, cold, tuberculosis, asthma and many more diseases. However, growth, yield and quality are constrained by excessive and under fertilization. This study was carried out to determine, firstly, the effect of N source (ammonium sulphate and calcium nitrate) on yield and quality of A. sativum and T. violacea plants. Secondly, to determine the best season for harvesting T. violacea and lastly, to determine the antifungal effects of A. sativum and T. violacea plant extracts against plant pathogens Altenaria solani and Sclerotium rolfsii. Both plants were treated with both N sources applied as topdressing treatments at a total of 0, 50, 100, 150 and 200 kg.ha-1, divided into three applications at three week (A. sativum) and three month (T. violacea) intervals. A. sativum plants were sampled at 54, 82, 112, 140 and 175 days after planting (DAP) while, T. violacea plants were sampled monthly for ten months. Parameters recorded were growth analysis, yield and bioactivity for both plant species. Both nitrogen sources improved plant growth and yield of A. sativum and T. violacea plants. Calcium nitrate at 150 kg•ha-1 and ammonium sulphate at 200 kg•ha-1 produced the highest at 24 t•ha-1 and 27 t•ha-1, respectively. Ammonium sulphate improved bioactivity of leaves with the highest bioactivity recorded at 82 and 112 DAP. Yield obtained from the autumn harvest was not affected by N source. Ammonium sulphate and calcium nitrate at 200 kg•ha-1 produced the highest yields of 23.6 t•ha-1 and 23.5 t•ha-1, respectively. In contrast, yield obtained from the winter harvest was affected by N source at 200 kg•ha-1, with significantly better yield of 30.8 t•ha-1 with calcium nitrate compared to 27.4 t•ha-1 with ammonium sulphate. Crude extracts of T. violacea bulbs that were treated with ammonium sulphate significantly inhibited the growth of plant pathogenic fungi, whereas extracts from plants treated with calcium nitrate showed low bioactivity. Extracts from plants grown with ammonium sulphate at 100 kg•ha-1 were more effective in controlling growth of plant pathogens when compared to other N levels. The minimum inhibitory concentration (MIC) effects of A. sativum against S. rolfsii and A. solani were at 0.01 mg•mL-1. The MIC of T. violacea extracts against A. solani was at 0.006 mg•mL<Sup>-1. The MIC of T. violacea extracts were better than previously reported in literature. Therefore, A. sativum and T. violacea plant extracts can be used as fungicides against S. rolfsii and A. solani diseases for crops such as tomato and potato. / Dissertation (MInstAgrar)--University of Pretoria, 2010. / Plant Production and Soil Science / unrestricted

Philosophiae Doctor - PhD / The reproductive health of individuals is severely compromised by HIV infection, with candidiasis being the most prevalent oral complication in patients. Although not usually associated with severe morbidity, oropharyngeal candidiasis can be clinically significant, as it can interfere with the administration of medications and adequate nutritional intake, and may spread to the esophagus. Azole antifungal agents are commonly prescribed for the treatment and prophylaxis of candidal infections. However, the emergence of drug resistant strains and dose limiting toxic effects have complicated the treatment of candidiasis. Consequently, safe and effective and affordable medicine is required to combat this fungus. Commercial garlic (Allium sativum) has been used time since immemorial as a natural antibiotic, however very little is known about the antifungal properties of two indigenous South African species of garlic, namely Tulbaghia alliacea and Tulbaghia violacea, that are used as folk medicines for a variety of infections. This study compares the in vitro anti-candidal activity of Tulbaghia alliacea, Tulbaghia violacea and Allium sativum extracts. It was found that the greatest concentrations of inhibitory components were extracted by chloroform or water. The IC50 concentrations of Tulbaghia alliacea were between 0.007 - 0.038% (w/v). Assays using S. cerevisiae revealed that the T. alliacea extract was fungicidal, with a killing half-life of approximately 2 hours. This inhibitory effect of the T. alliacea extracts was observed via TLC, and may be due to an active compound called Marasmicin, that was identified using NMR. This investigation confirms that extracts of T.alliacea exhibit anti-infective activity against candida species in vitro. / South Africa

Green garden peas (Pisum sativum L.) are a popular vegetable used in meal preparation worldwide. Green peas are commonly available in their frozen form due to their short growing season. Green peas are easily susceptible to changes in the field, immediately after harvest, during processing and storage, and thereforerequire careful handling to maintain good quality. The acceptability of frozen green peas is greatly dependent on the sensory quality. Descriptive sensory profiles and physico-chemical properties of frozen green peas can be investigated and used to assess and explain product quality. Six brands of frozen green peas representing product sold for retail and caterer's markets were purchased and subjected to descriptive sensory evaluation, physico-chemical analyses and quality grading. Four batches with different best before dates were purchased for each brand. Quality grading was done using statutory standards and a selected company protocol. Dry matter content, alcohol insoluble solids content, starch content, °Brix, residual peroxidase activity, size sorting, hardness using texture analysis and colour measurements were carried out for physico-chemical analyses. Generally, retail class peas were of superior sensory quality to caterer's peas although one caterer's brand had quality traits that were more comparable with the retail brands than the other caterer's brands. Quality grading revealed that frozen green peas can be downgraded due to poor colour, presence of extraneous vegetable matter, presence of sandy grits and soil stains, poor flavour and poor texture. Downgrading of peas can be due to one reason or due to a combination of two or more poor quality characteristics. Good quality peas were described as sweeter, smaller, greener, more moist and more tender than the poorer quality peas usingdescriptive sensory evaluation. Good peas also had high °Brix content, more intense green colour, low starch, alcohol insoluble solids, dry matter contents and texture hardness measured. Quality grading revealed that flavour problems were the major cause for low graded samples. Sensory evaluation and the methods used for instrumental analyses however, showed more easily the variations in texture attributes than flavour attributes of peas. Poor flavour was probably caused by ineffective blanching, low soluble solids content which enhanced the perception of bitterness and the presence of acetone notes. Poorly coloured peas were also either underblanched or had low moisture contents. Mealiness and hardness in peas were explained by high starch, alcohol insoluble solids and dry matter contents. Instrumental texture analysis showed indications that the harder peas also had tougher skins in addition to harder cotyledons. Lower peas also displayed characteristics typical of delayed harvesting and post-processing temperature abuse such as dehydration and pale green/white colouration. The sensory quality of frozen green peas can be predicted from the physico-chemical methods of analysis used in this study. Some of the frozen peas on sale are below the acceptable standards of quality. To achieve good frozen pea quality it is important to put emphasis on maturity at harvest and post processing storage conditions (store at -18 °C or lower and avoidfluctuatingtemperatures). The use of a strict quality grading scheme has been shownto result in good quality frozen peas. Copyright / Dissertation (MSc)--University of Pretoria, 2012. / Food Science / unrestricted

Submitted by Amauri Alves (amauri.alves@ufv.br) on 2015-11-05T15:19:50Z No. of bitstreams: 1 texto completo.pdf: 1256591 bytes, checksum: 7fb1f90875c23ff0319fba481041b6af (MD5) / Made available in DSpace on 2015-11-05T15:19:50Z (GMT). No. of bitstreams: 1 texto completo.pdf: 1256591 bytes, checksum: 7fb1f90875c23ff0319fba481041b6af (MD5) Previous issue date: 2013-08-21 / A aplicação de ON em sementes tem se mostrado promissora, uma vez que as sementes em contato com a solução de nitroprussiato de sódio (SNP), doador de ON, em geral, germinam mais e com maior velocidade, tolerando melhor tanto estresses abióticos como a deterioração natural ocasionada pelo armazenamento. Assim, na presente pesquisa, teve-se como objetivo avaliar as principais alterações que ocorrem na durante a germinação de sementes de ervilha devido à aplicação do ON. Para tanto, foram conduzidos dois experimentos. No primeiro experimento, três lotes de sementes de ervilha com diferentes níveis de qualidade fisiológica foram semeados em substrato umedecido com água (controle) ou com solução de SNP (50 μM). Adotou-se o delineamento inteiramente casualizado, com quatro repetições. Os dados foram submetidos à análise de variância e as médias foram analisadas pelo teste F a 5% de probabilidade. No segundo experimento, sementes de ervilha foram semeadas em substrato umedecido com água (controle), solução de polietilenoglicol [PEG 6000 (-0,15 MPa)] e solução de PEG 6000 + SNP (-0,15 MPa; 50 μM). O delineamento estatístico adotado foi inteiramente casualizado com quatro repetições. Os dados foram submetidos a análise de variância e as médias foram analisadas pelo teste Tukey a 5% de probabilidade. Conclui-se que o ON não aumenta a germinação das sementes de ervilha, entretanto há aumento no vigor. Sementes com menor potencial fisiológico respondem melhor à aplicação do ON. O estresse hídrico diminui a germinação e o vigor das sementes de ervilha e causa desbalanço das espécies reativas de oxigênio. A aplicação do SNP promoveu maior germinação e maior velocidade de germinação em sementes sob estresse hídrico. Houve maior atividade das amilases, das enzimas antioxidativas e menor conteúdo de H 2 O 2 , menor liberação de O 2- e menor peroxidação de lipídeos em sementes tratadas com doadores de ON. / The NO application in seeds has shown promising, because the seeds in contact with the sodium nitroprusside (SNP) solution, NO donor, usually germinates more and faster and are more tolerant to abiotic stresses such as natural deterioration caused by storage. Thus, it is interesting to know how the NO acts on the seeds germination to improve the early seedling development. Therefore, the research aimed to evaluate the main changes that occur during the germination of pea seeds due the NO application. Therefore, two experiments were conducted. In the first one, three lots of pea seeds with different physiological potential levels were sown in a substrate with water (control) or with SNP solution (50 μM). It was adopted the completely randomized design with four replications. The data were subjected to variance analysis and the means were analyzed by F test at 5% of probability. In the second experiment, pea seeds were sown in a substrate with water (control), polietilenoglicol [PEG 6000 solution (-0,15 MPa)] and PEG 6000 + SNP solution (-0,15 MPa; 50 μM). It was adopted the completely randomized design with four replications. The data were subjected to variance analysis and the means were analyzed by Tukey test at 5% of probability. To conclude, the NO does not increase the germination of pea seeds, but increase the seeds vigor. Seeds with lower physiological potential gives a better response to the NO application. Water stress decrease the germination and vigor of pea seeds and cause reactive oxygen species imbalance. The SNP application promoted a higher and faster germination in seeds under water stress. There were higher activity of the amylases, higher activity of the antioxidative enzymes, less H 2 O 2 content, less O 2- liberation and consequently less lipid peroxidation in seeds treated with NO.

A busca por embalagens flexíveis rapidamente degradáveis tem sido intensa nos anos mais recentes. Amidos de variadas fontes têm sido avaliados para a produção de filmes, sendo que a maioria destes apresenta boas características mecânicas e de barreira ao oxigênio, entretanto, uma série de limitações é observada com relação às suas características hidrofílicas e permeabilidade ao vapor d´água. O amido de ervilha normalmente apresenta teores mais elevados de amilose, o que pode melhorar a obtenção da rede formadora de filmes. Além disto, as associações amido-goma podem modificar a gelatinização e retrogradação do amido, processos que interferem na formação de filmes. O acréscimo de plastificantes também tem se mostrado de importância para melhorar as propriedades mecânicas dos filmes. Assim, o objetivo do presente trabalho foi avaliar o efeito da adição de goma xantana e de glicerol ao amido de ervilha verde de alto teor de amilose (cv. Utrillo) na elaboração de filmes e em suas características. Soluções filmogênicas (SF) com diferentes teores de amido de ervilha (3, 4 e 5%), de goma xantana (0, 0,05 e 0,1%) e de glicerol (proporção glicerol-amido de 1:5 p/p) foram estudadas. As SF foram obtidas por ebulição (5 min.), seguida de autoclavagem por 1h. a 120°C. Os filmes foram prepa rados segundo a técnica de casting. O aumento da concentração de amido na solução filmogênica aumentou a espessura, fator de ruptura, resistência à perfuração e solubilidade dos filmes em água. O aumento da concentração da goma xantana interferiu apenas nas propriedades associadas à cor dos filmes, aumentando os valores da tonalidade e decrescendo o croma a* e a transparência. O aumento da concentração do glicerol interferiu nas propriedades mecânicas dos filmes, gerando redução dos valores de resistência máxima à tração, tensão na ruptura, resistência à perfuração e fator de ruptura. O plastificante também gerou aumento do alongamento na ruptura, redução da transparência e aumento da espessura e da solubilidade do filme em água. / In the past few years, the attempt to obtain degradable flexible packaging has increased considerably. In this sense, starches obtained from different botanical sources have been evaluated to produce films. Most of these films present good mechanical characteristics and provide a good barrier to oxygen. Nevertheless, some limitations have been observed in relation to their hydrophilic properties and permeability to water vapor. Studies using starch from green peas with high levels of amylose to produce films were not found in the literature. The higher levels of amylose can improve the achievement of the matrix that forms films. In addition, starch-gum associations can modify starch gelatinization and retrogradation, processes which interfere with film formation. The addition of plasticizers has also been considered important to improve the mechanical properties of films. The aim of this study was to evaluate the effect of the addition of xanthan gum and glycerol to the starch of green peas with high content of amylose (cv. Utrillo) in the preparation of films and in their features. Filmogenic solution (FS) with different levels of pea starch (3, 4 and 5%), xanthan gum (0, 0.05 and 0.1%) and glycerol (glycerol-starch ratio of 1:5 p/p) were tested. The FS was obtained by boiling (5 min.), followed by autoclaving for 1h. at 120°C. The films were prepared by casting. The increased concentration of starch in the solution increased the thickness, factor of rupture, puncture force and solubility of films in water. Increasing amounts of xanthan affected only the properties associated with the color of the films, increasing the values of hue angle and decreasing the chroma a* and transparency. The increased concentration of glycerol interfered in the mechanical properties of the films, causing reduction of the maximum values of tensile strength, strain at break, puncture force and factor of rupture. The plasticizer also caused an increase of elongation at break, reduced transparency and increased thickness of the film and the solubility in water.

Natural products are biologically active metabolites produced by fungi, bacteria, and plants that have an extended application in pharmaceutical and chemical industries. Because of their chemical versatility, flavoenzymes are commonly involved in natural product biosynthetic pathways. This has given rise to the identification of flavoenzymes that are promising candidates for biomedical and biotechnical applications. This dissertation discusses the characterization of three flavoenzymes involved in natural product biosynthesis. The class B flavin-dependent monooxygenases S-monoooxygenase from Allium sativum (AsFMO) and N-hydroxylating monooxygenase from Streptomyces sp. XY332 (FzmM) were studied. Both enzymes perform heteroatom oxidation as part of allicin or fosfazinomycin biosynthesis respectively. AsFMO was predicted to oxidize S-allyl-L-cysteine (SAC) to alliin in allicin biosynthesis. Surprisingly, AsFMO exhibited negligible activity with SAC, and instead was highly active with allyl mercaptan and NADPH. This contradicted the initial proposal and suggested that AsFMO is involved in an alternative path producing allicin directly from allyl mercaptan. FzmM was identified to perform multiple N-oxidations which lead to the formation of a nitro group. FzmM performed a highly coupled and specific reaction with L-aspartate and NADPH to produce nitrosuccinate. Both AsFMO and FzmM followed a kinetic mechanism representative of class B flavin-dependent monooxygenases with a rapid pro-R stereospecific reduction and the formation of a C(4a)-hydroperoxyflavin intermediate during oxidation. In addition, the AsFMO structure was obtained and consisted of two domains for FAD and NADPH binding signature of class B monooxygenases. The biochemical and structural study of the Acinetobacter baumannii siderophore interacting protein (BauF) was also accomplished. This enzyme is essential in acinetobactin mediated iron assimilation and is important for virulence. The characterization of the binding and reduction of acinetobactin-ferric iron complex revealed that BauF is specific for this substrate and does not utilize NAD(P)H as an electron donor. The unique activity and structure of BauF can aid future drug design. / Doctor of Philosophy / Plants, fungi, and bacteria synthesize and excrete unique chemicals called secondary metabolites or natural products. These compounds are used for many applications including dyes, flavorings, fragrances, and medicine. To make natural products, organisms use enzymes to perform complex reactions. Studying the enzymes that are involved in natural product pathways is important for understanding how secondary metabolites are made. Additionally, these enzymes can be engineered to perform reactions relevant to biotechnical applications. Our lab specializes in the study of flavoenzymes which use flavin chemistry for catalysis. Flavin is a yellow coenzyme that contributes to wide array of reactions by performing 1 or 2 electron transfers. This dissertation discussed the characterization of three flavoenzymes. The first enzyme is a S- monooxygenase from Allium sativum (garlic) called AsFMO. Reported here is the kinetic and structural characterization of AsFMO. We demonstrated that AsFMO was cabable of performing an unexpected reaction with allyl mercaptan likely converting it into allicin, the main flavor ingredient of garlic. Secondly, we reported the kinetic characterization of a nitro- forming enzyme termed FzmM. Nitro- formation is a valuable process as nitro- compounds are used in industrial organic synthesis. It was shown that FzmM performs nitro- formation with high efficiency and is specific for the substrate L-aspartate. Lastly, this work described the characterization of the the siderophore-interacting protein from Acinetobacter baumannii, BauF, which was predicted to be involved in iron acqusition. A. baumannii is a serious human pathogen with multidrug resistance, and inhibiting iron acquisition has been shown to prevent its survival. The characterization of the enzymes involved in this pathway is essential for developing new treatments for A. baumannii infection. We report the structure and function of BauF confirming its role in A. baumannii iron uptake and providing information that will aid in future drug design.

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