Dissertations / Theses on the topic 'Seed addition'

Cold pressed Hemp (Cannabis sativa L) seed oil, which contains a favorable ratio of omega-6/omega-3 and a considerable amount of vitamin E, is a high nutrition value product with various health benefits. However, the presence of a large amount of chlorophyll makes the oil highly susceptible to photo-oxidation and limits its applications. Chlorophyll and other pigments in edible oils are commonly reduced through oil bleaching process. The objective of this study was to reduce the chlorophyll content in cold pressed hemp seed oil using ultrasonic bleaching and evaluate the impacts on carotene content, peroxide value, conjugated diene, total phenolic content and oxidative stability. The bleaching efficiency increased significantly as the ultrasound power (0 to 60% pressure amplitude) and concentration of bleaching clay (20 to 40 g/kg) increased. At 20% ultrasound power, the chlorophyll reduction (%) of different clays was found to be 99.4% (industrial clay) > 97.8% (activated bentonite) > 82.7% (sepiolite) > 47.1% (non-activated bentonite). Ultrasonic bleaching significantly reduced (p<0.05) the total chlorophyll content, total carotene content and primary oxidation products of hemp seed oil. During accelerated oxidation tests (40 and 60 ℃), the developments of peroxide value and conjugated diene were significantly (p<0.05) slower for hemp seed oil treated with ultrasonic bleaching compared to the control oil. Enhanced oxidative stability was observed in hemp seed oil after ultrasonic bleaching. In addition, another objective of this study was to evaluate the impacts of solvent and heat treatment on phenolic profile and antioxidant activity of cold pressed canola and hemp meals. For canola meal, a solvent-mixture of aqueous methanol (70%) and aqueous acetone (70%) in a ratio of 1:1 (v/v) extracted (p<0.05) slightly higher total phenolic content (11.3 mg SAE/g), while aqueous methanol (70%) extracts exhibited higher DPPH scavenging effect (40.4%). For hemp meal, aqueous acetone (80%) extracts exhibited higher total phenolic content (6.0 mg GAE/g) and DPPH scavenging effect (12.5%). Total phenolic content and antioxidant activity in canola meal extracts were significantly higher (p<0.05) than those in hemp meal extracts. After heat treatments at temperature from 140 to 180 ℃, canola and hemp meal extracts showed equal or lower total phenolic content and DPPH scavenging effect.
May 2017

Despite extensive international acceptance of the critical role of mammalian post-dispersal seed predation in many plant communities, in New Zealand we have limited knowledge of these predators’ influence on plant recruitment in our forests. The principle objective of my thesis was to determine the importance of exotic mammals as post-dispersal seed predators in a New Zealand conifer-broadleaf forest remnant. To address this goal, I used a series of field-based experiments where the actions of different post-dispersal seed predators were separated by wire-mesh exclosures. My study was conducted at Mount Peel Forest Park Scenic Reserve, South Canterbury, New Zealand. Being a human modified conifer forest currently dominated by broadleaf species, it is typical of forest remnants in New Zealand. This presented an opportunity to study a wide range of both potential post-dispersal seed predators and broadleaf tree species. My findings indicate that exotic mammals are not only post-dispersal seed predators at Peel Forest, but are responsible for the majority of post-dispersal predation events observed. Ship rats (Rattus rattus) were the dominant post-dispersal seed predators, while brushtail possums (Trichosurus vulpecula), house mice (Mus musculus) and native invertebrates were also important post-dispersal seed predators for several tree species. Through use of time-lapse video and cafeteria experiments I found that exotic mammalian seed predators, when compared to native invertebrate seed predators, preyed upon larger-seeded plant species and were responsible for considerable seed losses of several tree species. However, exotic mammalian seed predators do share several foraging characteristics with native invertebrate seed predators, as predators foraged in similar habitats and responded in a similar way to changes in seed density. In investigating if post-dispersal seed predation by mammals had a flow-on effect to plant recruitment, I observed natural seedling densities at Peel Forest were significantly higher in the absence of mammalian seed predators, but I found no evidence that the presence of mammals significantly altered the overall species richness. At the community level, I did not find an interaction between habitat and exotic mammals, however I present evidence that for individual plant species a significant mammal : habitat interaction occurred. Consequently, even though my cafeteria experiment implied there was no significant difference in the overall amount of seed preyed upon within different habitats, the less favourable microsite conditions for germination under an intact continuous canopy allows mammals to exacerbate habitat-related patterns of seed mortality and have a noticeable effect on seedling establishment. In an effort to validate the use of manipulative experiments to predict the long-term effect of post-dispersal seed predation on plant dynamics, I attempted to link results of my cafeteria experiment with observed seedling abundance at Peel Forest. Seven tree species were used in this comparison and a strong correlation was observed. This result shows that the level of post-dispersal seed predation determined in the cafeteria experiment provided a good predictor of the effect of mammalian post-dispersal seed predation on seedling establishment. To fully gauge the impact of mammalian post-dispersal seed predators on seedling establishment, the relationship between these seed predators and the type of recruitment limitation experienced by a plant species was also investigated. By using a combination of seed addition, plot manipulations and seed predator exclusion I was able to investigate this relationship. I found evidence that seed limitation at Peel Forest is positively correlated with seed size, and that while mammalian post-dispersal seed predators can further reduce plant recruitment of plant species experiencing seed limitation, the influence of mammals in determining plant recruitment was limited for plant species experiencing microsite limitation. My study has proven that exotic mammals are now the dominant post-dispersal seed predators at Peel Forest, the amount of seed preyed upon varies among plant species, and post-dispersal seed predation by mammalian species can lead to differences in seedling richness and abundance. I proved that the influence of exotic mammals on seedling establishment is also linked to habitat structure and recruitment limitations. When combined these observations suggest that exotic mammalian post-dispersal seed predators may play an important role in determining landscape abundance and distribution of plants at Peel Forest.

Master of Science
Division of Biology
John M. Blair
Temperate grasslands are among the most threatened biomes in the world, with the largest historical losses due to conversion to agricultural land. While much of this biome has already been converted, there is concern the last remaining remnants in North America will be converted in response to increasing demand for crops used for ethanol production. Thus, restoring grasslands post-anthropogenic disturbance is increasingly important for conserving grassland biodiversity. Two major challenges for prairie restorations are establishing the many subdominant and rarer species found in native prairie, and offsetting the typical decline in richness and diversity over time as restorations age. Repeated seed addition of targeted species is commonly used to override low and declining plant richness and diversity. While this is generally effective early in restoration (i.e., as communities are establishing), its effectiveness in later stages (i.e., when established communities are often losing diversity) remains unknown. I investigated plant community responses to combinations of resource manipulations and disturbances coupled with a seed addition in a 15-yr old restored grassland to test the hypothesis that spatial resource heterogeneity increases the rate of colonization into established prairie restoration communities. Seeds were added to a long-term restoration experiment involving soil depth manipulations (deep, shallow) crossed with nutrient manipulations (reduced N, ambient N, enriched N). Seedling emergence was generally low and only 8 of the 14 forb species added were detected in the first growing season. I found no effect of increased resource heterogeneity on the abundance or richness of seedlings. There was a significant nutrient effect (p<0.1, α=0.1) on seedling abundance, with higher emergence in the enriched N than the ambient N treatment. I also found unexpected nutrient effects on richness, diversity and Mean C (Mean C = Σ CoCi*Ai, where CoC=Coefficient of Conservatism and A=relative abundance of the ith species). All values, except Mean C, were higher in the enriched N treatment than in either the reduced or ambient N treatments. Mean C was lowest in the enriched N treatment, and highest in the whole-plot control, suggesting that the majority of species contributing to higher richness and diversity in the enriched N treatment were “weedier” species. In a separate experiment, I found no effect of small-scale disturbances (aboveground biomass removal or soil disturbance) on seedling abundance or seedling richness. I did find a marginal effect of disturbance type on seedling richness (p=0.11, α=0.1), with higher seedling richness in the soil disturbance than the aboveground biomass removal treatment. I did not find any disturbance effects on community response variables. These results indicate that recruitment from seed additions into well-established restored communities is relatively low in the first year following a seed addition, regardless of resource availability and heterogeneity. Follow-up studies to determine recruitment rates in subsequent years are needed to elucidate whether recruitment responses are driven more by individual species differences or by environmental mechanisms.

Optical see-through display (OSTD) is a transparent digital display which simultaneously gives access to the digital contents and the real world objects behind it. Additive optical see-though display is a hardware subtype of OSTD which has its own light source to create the digital contents. In Additive OSTD, light coming from background objects mixes with the light originating from the display causing what is known as the color blending problem. The work in this thesis provides a solution to the color blending problem. In order to understand the problem, this thesis first presents a new color blending model for additive OSTD based on two display induced distortions: the Render distortion and the Material distortion. A new method called Binned Profile (BP) method which accounts for the render distortion is developed to predict the blended color, when applied on the color blending model. BP method is validated with other known methods and is shown to be the most accurate in predicting the color blends with 9 just noticeable differences (JND) in worst case. Based on the BP method, a new color correction algorithm called BP color correction is created to solve the color blending problem. BP-color correction finds the alternative digital color to counter balance the blending. The correction capacity of various digital colors were analysed using the BP color correction approach. BP color correction is also compared and proven to be better than the existing solution. A quicker version of the correction called quick correction is also explored. The thesis concludes with an exploration of the material distortion, explains the limitations of BP-correction, provides design recommendations .

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
The mango is one of the most popular fruits in Brazil, and the best know type is Mangifera indica L. The production of this fruit is seasonal and its industrialization has grown in the last years as a means of diminishing loss in the harvest time. The mango processing generates a great amount of residues, around 40 to 60% of the entire amount of raw material. From the residues generated, 12 to 15% is made up of peel and 15 to 20% is seeds. The residues cannot be accumulated indefinitely where they were produced, and are normally discarded with no previous treatment, far from the processing unit. In this sense, the use of the mango seed as a source of cellulose is an alternative in order to diminish the loss and impact on the environment. In this study, the mango seed of the Ubá variety of mangifera indica L. was used as a source of cellulose. The mango seed, originating from a juice factory in the municipality of Araguari-MG, showed a content of cellulose of 55.00% ± 1.0, while the content of Klason lignin was 23.85% ± 0.3. The fibres of the mango seed were used in the production of methylcellulose and the samples were produced by means of heterogeneous methylation using dimethyl sulfate (DMS) and iodomethane as alkylating agents. The methylcelluloses produced were characterized as to their thermal properties by means of scanning exploratory calorimetry (DSC) and thermogravimetric analysis (TGA). The crystalline fraction of the polymers was determined by diffraction of X-rays (DRX), and the substitution degrees (GS) were determined by chemical means. The GS values, determined by chemical means were of 1.35 for MCD and 0.45 for MCI, showing a higher substitution in the synthesis using DMS as methylation agent. Aqueous solutions of methylcellulose, in the concentration of 0.2% m/m and 0.6% m/m (polymer mass/cement mass) were used as an additive in mortar and its effect was assessed, when newly prepared, by means of Consistency Index (CI) tests, density and water retention. After hardened, tests by means of the assessment of potential resistance in adherence and traction (Ra) were carried out. The methylcellulose samples obtained with DMS (MCD) and iodomethane (MCI) as methylate agents, used in the proportion of 0.6% w/w, showed better result; the increase was of 27.75% and 71.54% in the IC and an increase of 23.33% and 26.67% respectively in the Ra, showing that polymers can be used in the production of adhesive mortars.
A manga é uma das frutas mais populares no Brasil, sendo a espécie mais difundida a Mangifera indica L. A produção dessa fruta é sazonal e sua industrialização tem crescido nos últimos anos como forma de diminuir as perdas no período de safra. O processamento da manga gera uma grande quantidade de resíduos, em torno de 40 a 60% de toda a matéria prima. Dos resíduos gerados 12 a 15 % são constituídos de cascas e de 15 a 20% de sementes. Os resíduos não podem ser acumulados indefinidamente no local onde foram produzidos e geralmente são descartados sem um tratamento prévio, longe da unidade processadora. Nesse sentido a utilização do caroço de manga como fonte de celulose se torna uma alternativa para diminuir as perdas e o impacto ambiental. No presente trabalho, o caroço de manga, Mangifera indica L. variedade Ubá, foi utilizado como fonte de celulose. O caroço de manga, proveniente de uma fábrica de suco do município de Araguari-MG, apresentou um teor de celulose de 55,00 % ± 1,0, enquanto o teor de lignina Klason foi de 23,85 % ± 0,3. As fibras do caroço de manga foram utilizadas para produção de metilcelulose e as amostras foram produzidas através da metilação heterogênea, utilizando-se o dimetilsulfato (DMS) e o iodometano como agentes alquilantes. As metilceluloses produzidas foram caracterizadas quanto às propriedades térmicas por calorimetria exploratória de varredura (DSC) e análise termogravimétrica (TGA). A fração cristalina dos polímeros foi determinada por difração de raios-X (DRX), e os graus de substituição (GS) foram determinados por via química. Os valores de GS, determinados por via química, foram de 1,35 para a MCD e 0,45 para a MCI, demonstrando uma maior substituição na síntese utilizando DMS como agente metilante. Soluções aquosas de metilcelulose, na concentração de 0,2 % m/m e 0,6% m/m (massa de polímero/massa de cimento), foram empregadas como aditivo em argamassas e o seu efeito foi avaliado, no estado fresco, através de ensaios de Índice de Consistência (IC), densidade e retenção de água. No estado endurecido, através da resistência potencial de aderência à tração (Ra). As amostras de metilcelulose obtidas com DMS (MCD) e iodometano (MCI) como agentes metilantes, utilizadas na proporção de 0,6% m/m, apresentaram um melhor resultado, sendo que o aumento foi de 27,75 % e 71,54 % no (IC) e um aumento na Ra de 23,33 % e 26,67%, respectivamente, mostrando que os polímeros podem ser empregados na produção de argamassas adesivas.
Doutor em Química

La miniaturisation nécessaire à l'accroissement des performances des composants microélectroniques est en passe d'atteindre ses limites. Ainsi, une nouvelle approche dite " intégration 3D " semble prometteuse pour outrepasser les limitations observées. Cette nouvelle intégration consiste à empiler les différentes puces qui sont reliées entre elles par des vias appelées Through Silicon Vias (TSV). L'une des clés pour la réalisation de circuits en 3 dimensions est la métallisation des TSVs. Cette dernière nécessite les dépôts d'une barrière et d'une couche d'accroche qui sert à initier le remplissage par électrolyse. Ces travaux s'intéressent plus spécifiquement à la réalisation de la couche d'accroche et au remplissage des TSVs.La couche d'accroche est généralement déposée par pulvérisation, ce qui ne permet pas d'obtenir une couverture de marche satisfaisante pour la réalisation du remplissage. Cette étude propose une solution électrolytique appelée SLE (Seed Layer Enhancement) qui permet de restaurer la continuité de la couche d'accroche déposée par PVD. L'application de ce procédé associé à un traitement de désoxydation de la surface permet l'optimisation de la nucléation du cuivre et donc la réalisation d'une couche de cuivre continue et conforme. Le procédé SLE a été intégré à la séquence de métallisation et a démontré sa capacité à initier un remplissage superconforme. De plus, des tests électriques ont confirmé l'efficacité du procédé SLE une fois intégré. Ces expériences ont ouvert la voie à l'étude du dépôt électrolytique de cuivre direct sur la barrière à la diffusion du cuivre, c'est le procédé Direct On Barrier. Les premiers résultats ont permis de démontrer la possibilité de déposer une couche de cuivre conforme sur des barrières résistives. Le second volet de ces travaux s'intéresse au remplissage par électrolyse des TSVs. Dans ce but, deux électrolytes (d'ancienne et de nouvelle génération) ont été considérés. L'effet des additifs sur le dépôt et leurs actions sur le remplissage superconforme ont été étudiés par voltampérométrie et chronopotentiométrie pour chacune des solutions. Ces analyses ont permis de monter deux mécanismes de remplissage différents principalement dû à l'action de l'additif inhibiteur durant l'électrolyse. Contrairement au cas de l'électrolyte d'ancienne génération inspiré des procédés pour le damascène, l'inhibiteur de l'électrolyte de nouvelle génération s'adsorbe fortement et irréversiblement à la surface du cuivre. Il bloque efficacement la croissance sur les flancs et le haut des TSVs, sans toutefois pouvoir contrarier l'action de l'accélérateur en fond de motif.

O Vírus da Imunodeficiência Humana (HIV) é o agente etiológico da Síndrome da Imunodeficiência Adquirida (AIDS). A AIDS é uma doença de distribuição mundial, e estima-se que existam atualmente pelo menos 36,9 milhões de pessoas infectadas com o vírus. Durante o seu ciclo replicativo, o HIV promove diversas alterações na fisiologia da célula hospedeira a fim de promover sua sobrevivência e potencializar a replicação. A rápida progressão da infecção pelo HIV-1 em humanos e em modelos animais está intimamente ligada à função da proteína acessória Nef. Dentre as diversas ações de Nef está a regulação negativa de proteínas importantes na resposta imunológica, como o receptor CD4. Sabe-se que esta ação resulta da indução da degradação de CD4 em lisossomos, mas os mecanismos moleculares envolvidos ainda são totalmente elucidados. Nef forma um complexo tripartite com a cauda citosólica de CD4 e a proteína adaptadora 2 (AP-2), em vesículas revestidas por clatrina nascentes, induzindo a internalização e degradação lisossomal de CD4. Pesquisas anteriores demonstraram que o direcionamento de CD4 aos lisossomos por Nef envolve a entrada do receptor na via dos corpos multivesiculares (MVBs), por um mecanismo atípico, pois, embora não necessite da ubiquitinação de carga, depende da ação de proteínas que compõem os ESCRTs (Endosomal Sorting Complexes Required for Transport) e da ação de Alix, uma proteína acessória da maquinaria ESCRT. Já foi reportado que Nef interage com subunidades dos complexos AP-1, AP-2, AP-3 e Nef não parece interagir com subunidades de AP-4 e AP-5. Entretanto, o papel da interação de Nef com AP-1 e AP-3 na regulação negativa de CD4 ainda não está totalmente elucidado. Ademais, AP-1, AP-2 e AP-3 são potencialmente heterogêneos devido à existência de isoformas múltiplas das subunidades codificadas por diferentes genes. Todavia, existem poucos estudos para demonstrar se as diferentes combinações de isoformas dos APs são formadas e se possuem propriedades funcionais distintas. O presente trabalho procurou identificar e caracterizar fatores celulares envolvidos na regulação do tráfego intracelular de proteínas no processo de regulação negativa de CD4 induzido por Nef. Mais especificamente, este estudo buscou caracterizar a participação do complexo AP-1 na modulação negativa de CD4 por Nef de HIV-1, através do estudo funcional das duas isoformas de ?-adaptina, subunidades de AP-1. Utilizando a técnica de Pull-down demonstramos que Nef é capaz de interagir com ?2. Além disso, nossos dados de Imunoblot indicaram que a proteína ?2-adaptina, e não ?1-adaptina, é necessária no processo de degradação lisossomal de CD4 por Nef e que esta participação é conservada para degradação de CD4 por Nef de diferentes cepas virais. Ademais, por citometria de fluxo, o silenciamento de ?2, e não de ?1, compromete a diminuição dos níveis de CD4 por Nef da membrana plasmática. A análise por imunofluorêsncia indireta também revelou que a diminuição dos níveis de ?2 impede a redistribuição de CD4 por Nef para regiões perinucleares, acarretando no acúmulo de CD4, retirados por Nef da membrana plasmática, em endossomos primários. A depleção de ?1A, outra subunidade de AP-1, acarretou na diminuição dos níveis celulares de ?2 e ?1, bem como, no comprometimento da eficiente degradação de CD4 por Nef. Além disso, foi possível observar que, ao perturbar a maquinaria ESCRT via super-expressão de HRS (uma subunidade do complexo ESCRT-0), ocorreu um acumulo de ?2 em endossomos dilatados contendo HRS-GFP, nos quais também detectou-se CD4 que foi internalizado por Nef. Em conjunto, os resultados indicam que ?2-adaptina é uma importante molécula para o direcionamento de CD4 por Nef para a via ESCRT/MVB, mostrando ser uma proteína relevante no sistema endo-lisossomal. Ademais, os resultados indicaram que as isoformas ?-adaptinas não só possuem funções distintas, mas também parecem compor complexos AP-1 com diferentes funções celulares, já que apenas a variante AP-1 contendo ?2, mas não ?1, participa da regulação negativa de CD4 por Nef. Estes estudos contribuem para o melhor entendimento dos mecanismos moleculares envolvidos na atividade de Nef, que poderão também ajudar na melhor compreensão da patogênese do HIV e da síndrome relacionada. Em adição, este trabalho contribui para o entendimento de processos fundamentais da regulação do tráfego de proteínas transmembrana no sistema endo-lisossomal.
The Human Immunodeficiency Virus (HIV) is the etiologic agent of Acquired Immunodeficiency Syndrome (AIDS). AIDS is a disease which has a global distribution, and it is estimated that there are currently at least 36.9 million people infected with the virus. During the replication cycle, HIV promotes several changes in the physiology of the host cell to promote their survival and enhance replication. The fast progression of HIV-1 in humans and animal models is closely linked to the function of an accessory protein Nef. Among several actions of Nef, one is the most important is the down-regulation of proteins from the immune response, such as the CD4 receptor. It is known that this action causes CD4 degradation in lysosome, but the molecular mechanisms are still incompletely understood. Nef forms a tripartite complex with the cytosolic tail of the CD4 and adapter protein 2 (AP-2) in clathrin-coated vesicles, inducing CD4 internalization and lysosome degradation. Previous research has demonstrated that CD4 target to lysosomes by Nef involves targeting of this receptor to multivesicular bodies (MVBs) pathway by an atypical mechanism because, although not need charging ubiquitination, depends on the proteins from ESCRTs (Endosomal Sorting Complexes Required for Transport) machinery and the action of Alix, an accessory protein ESCRT machinery. It has been reported that Nef interacts with subunits of AP- 1, AP-2, AP-3 complexes and Nef does not appear to interact with AP-4 and AP-5 subunits. However, the role of Nef interaction with AP-1 or AP-3 in CD4 down-regulation is poorly understood. Furthermore, AP-1, AP-2 and AP-3 are potentially heterogeneous due to the existence of multiple subunits isoforms encoded by different genes. However, there are few studies to demonstrate if the different combinations of APs isoforms are form and if they have distinct functional properties. This study aim to identify and characterize cellular factors involved on CD4 down-modulation induced by Nef from HIV-1. More specifically, this study aimed to characterize the involvement of AP-1 complex in the down-regulation of CD4 by Nef HIV-1 through the functional study of the two isoforms of ?-adaptins, AP-1 subunits. By pull-down technique, we showed that Nef is able to interact with ?2. In addition, our data from immunoblots indicated that ?2- adaptin, not ?1-adaptin, is required in Nef-mediated targeting of CD4 to lysosomes and the ?2 participation in this process is conserved by Nef from different viral strains. Furthermore, by flow cytometry assay, ?2 depletion, but not ?1 depletion, compromises the reduction of surface CD4 levels induced by Nef. Immunofluorescence microscopy analysis also revealed that ?2 depletion impairs the redistribution of CD4 by Nef to juxtanuclear region, resulting in CD4 accumulation in primary endosomes. Knockdown of ?1A, another subunit of AP-1, resulted in decreased cellular levels of ?1 and ?2 and, compromising the efficient CD4 degradation by Nef. Moreover, upon artificially stabilizing ESCRT-I in early endosomes, via overexpression of HRS, internalized CD4 accumulates in enlarged HRS-GFP positive endosomes, where co-localize with ?2. Together, the results indicate that ?2-adaptin is a molecule that is essential for CD4 targeting by Nef to ESCRT/MVB pathway, being an important protein in the endo-lysosomal system. Furthermore, the results indicate that ?-adaptins isoforms not only have different functions, but also seem to compose AP-1 complex with distinct cell functions, and only the AP-1 variant comprising ?2, but not ?1, acts in the CD4 down-regulation induced by Nef. These studies contribute to a better understanding on the molecular mechanisms involved in Nef activities, which may also help to improve the understanding of the HIV pathogenesis and the related syndrome. In addition, this work contributes with the understanding of primordial process regulation on intracellular trafficking of transmembrane proteins.

Doutoramento em Bioquímica
Os polissacarídeos são os componentes maioritários dos grãos de café verde e torrado e da bebida de café. Os mais abundantes são as galactomananas, seguindo-se as arabinogalactanas. Durante o processo de torra, as galactomananas e arabinogalactanas sofrem modificações estruturais, as quais estão longe de estar completamente elucidadas devido à sua diversidade e à complexidade estrutural dos compostos formados. Durante o processo de torra, as galactomananas e arabinogalactanas reagem com proteínas, ácidos clorogénicos e sacarose, originando compostos castanhos de alto peso molecular contendo nitrogénio, designados de melanoidinas. As melanoidinas do café apresentam diversas atividades biológicas e efeitos benéficos para a saúde. No entanto, a sua estrutura exata e os mecanismos envolvidos na sua formação permanecem desconhecidos, bem como a relação estrutura-atividade biológica. A utilização de sistemas modelo e a análise por espectrometria de massa permitem obter uma visão global e, simultaneamente, detalhada das modificações estruturais nos polissacarídeos do café promovidas pela torra, contribuindo para a elucidação das estruturas e mecanismos de formação das melanoidinas. Com base nesta tese, oligossacarídeos estruturalmente relacionados com a cadeia principal das galactomananas, (β1→4)-Dmanotriose (Man3), e as cadeias laterais das arabinogalactanas, (α1→5)-Larabinotriose (Ara3), isoladamente ou em misturas com ácido 5-Ocafeoilquínico (5-CQA), o ácido clorogénico mais abundante nos grãos de café verde, e péptidos compostos por tirosina e leucina, usados como modelos das proteínas, foram sujeitos a tratamento térmico a seco, mimetizando o processo de torra. A oxidação induzida por radicais hidroxilo (HO•) foi também estudada, uma vez que estes radicais parecem estar envolvidos na modificação dos polissacarídeos durante a torra. A identificação das modificações estruturais induzidas por tratamento térmico e oxidativo dos compostos modelo foi feita por estratégias analíticas baseadas principalmente em espectrometria de massa, mas também em cromatografia líquida. A cromatografia de gás foi usada na análise de açúcares neutros e ligações glicosídicas. Para validar as conclusões obtidas com os compostos modelo, foram também analisadas amostras de polissacarídeos do café obtidas a partir de resíduo de café e café instantâneo. Os resultados obtidos a partir dos oligossacarídeos modelo quando submetidos a tratamento térmico (seco), assim como à oxidação induzida por HO• (em solução), indicam a ocorrência de despolimerização, o que está de acordo com estudos anteriores que reportam a despolimerização das galactomananas e arabinogalactanas do café durante a torra. Foram ainda identificados outros compostos resultantes da quebra do anel de açúcares formados durante o tratamento térmico e oxidativo da Ara3. Por outro lado, o tratamento térmico a seco dos oligossacarídeos modelo (individualmente ou quando misturados) promoveu a formação de oligossacarídeos com um maior grau de polimerização, e também polissacarídeos com novos tipos de ligações glicosídicas, evidenciando a ocorrência de polimerização através reações de transglicosilação não enzimática induzidas por tratamento térmico a seco. As reações de transglicosilação induzidas por tratamento térmico a seco podem ocorrer entre resíduos de açúcares provenientes da mesma origem, mas também de origens diferentes com formação de estruturas híbridas, contendo arabinose e manose como observado nos casos dos compostos modelo usados. Os resultados obtidos a partir de amostras do resíduo de café e de café instantâneo sugerem a presença de polissacarídeos híbridos nestas amostras de café processado, corroborando a ocorrência de transglicosilação durante o processo de torra. Além disso, o estudo de misturas contendo diferentes proporções de cada oligossacarídeo modelo, mimetizando regiões do grão de café com composição distinta em polissacarídeos, sujeitos a diferentes períodos de tratamento térmico, permitiu inferir que diferentes estruturas híbridas e não híbridas podem ser formadas a partir das arabinogalactanas e galactomananas, dependendo da sua distribuição nas paredes celulares do grão e das condições de torra. Estes resultados podem explicar a heterogeneidade de estruturas de melanoidinas formadas durante a torra do café. Os resultados obtidos a partir de misturas modelo contendo um oligossacarídeo (Ara3 ou Man3) e 5-CQA sujeitas a tratamento térmico a seco, assim como de amostras provenientes do resíduo de café, mostraram a formação de compostos híbridos compostos por moléculas de CQA ligadas covalentemente a um número variável de resíduos de açúcar. Além disso, os resultados obtidos a partir da mistura contendo Man3 e 5-CQA mostraram que o CQA atua como catalisador das reações de transglicosilação. Por outro lado, nas misturas modelo contendo um péptido, mesmo contendo também 5-CQA e sujeitas ao mesmo tratamento, observou-se uma diminuição na extensão das reações transglicosilação. Este resultado pode explicar a baixa extensão das reações de transglicosilação não enzimáticas durante a torra nas regiões do grão de café mais ricas em proteínas, apesar dos polissacarídeos serem os componentes maioritários dos grãos de café. A diminuição das reações de transglicosilação na presença de péptidos/proteínas pode dever-se ao facto de os resíduos de açúcares redutores reagirem preferencialmente com os grupos amina de péptidos/proteínas por reação de Maillard, diminuindo o número de resíduos de açúcares redutores disponíveis para as reações de transglicosilação. Além dos compostos já descritos, uma diversidade de outros compostos foram formados a partir dos sistemas modelo, nomeadamente derivados de desidratação formados durante o tratamento térmico a seco. Em conclusão, a tipificação das modificações estruturais promovidas pela torra nos polissacarídeos do café abre o caminho para a compreensão dos mecanismos de formação das melanoidinas e da relação estrutura-atividade destes compostos.
Polysaccharides are the major components of green and roasted coffee beans, and coffee brew. The most abundant ones are galactomannans, followed by arabinogalactans. During the roasting process, galactomannans and arabinogalactans undergo structural modifications that are far to be completely elucidated due to their diversity and complexity of the compounds formed. During the roasting process, galactomannans and arabinogalactans react with proteins, chlorogenic acids, and sucrose, originating high molecular weight brown compounds containing nitrogen, known as melanoidins. Several biological activities and beneficial health effects have been attributed to coffee melanoidins. However, their exact structures and the mechanisms involved in their formation remain unknown, as well as the structure-biological activity relationship. The use of model systems and mass spectrometry analysis allow to obtain an overall view and, simultaneously, detailed, of the structural modifications in coffee polysaccharides promoted by roasting, contributing to the elucidation of the structures and formation mechanisms of melanoidins. Based on this thesis, oligosaccharides structurally related to the backbone of galactomannans, (β1→4)-D-mannotriose, and the side chains of arabinogalactans, (α1→5)-Larabinotriose, alone or in mixtures with 5-O-caffeoylquinic acid, the most abundant chlorogenic acid in green coffee beans, and dipeptides composed by tyrosine and leucine, used as models of proteins, were submitted to dry thermal treatments, mimicking the coffee roasting process. The oxidation induced by hydroxyl radicals (HO•) was also studied, since these radicals seem to be involved in the modification of the polysaccharides during roasting. The identification of the structural modifications induced by thermal and oxidative treatment of the model compounds was performed mostly by mass spectrometry-based analytical strategies, but also using liquid chromatography. Gas chromatography was used in the analysis of neutral sugars and glycosidic linkages. To validate the conclusions achieved with the model compounds, coffee polysaccharide samples obtained from spent coffee grounds and instant coffee were also analysed. The results obtained from the model oligosaccharides when submitted to thermal treatment (dry) or oxidation induced by HO• (in solution) indicate the occurrence of depolymerization, which is in line with previous studies reporting the depolymerization of coffee galactomannans and arabinogalactans during roasting. Compounds resulting from sugar ring cleavage were also formed during thermal treatment and oxidative treatment of Ara3. On the other hand, the dry thermal treatment of the model oligosaccharides (alone or when mixed) promoted the formation of oligosaccharides with a higher degree of polymerization, and also polysaccharides with new type of glycosidic linkages, evidencing the occurrence of polymerization via non-enzymatic transglycosylation reactions induced by dry thermal treatment. The transglycosylation reactions induced by dry thermal treatment can occur between sugar residues from the same origin, but also of different origins, with formation of hybrid structures, containing arabinose and mannose in the case of the model compounds used. The results obtained from spent coffee grounds and instant coffee samples suggest the presence of hybrid polysaccharides in these processed coffee samples, corroborating the occurrence of transglycosylation during the roasting process. Furthermore, the study of mixtures containing different proportions of each model oligosaccharide, mimicking coffee bean regions with distinct polysaccharide composition, subjected to different periods of thermal treatment, allowed to infer that different hybrid and non-hybrid structures may be formed from arabinogalactans and galactomannans, depending on their distribution in the bean cell walls and on roasting conditions. These results may explain the heterogeneity of melanoidins structures formed during coffee roasting. The results obtained from model mixtures containing an oligosaccharide (Ara3 or Man3) and 5-CQA and subjected to dry thermal treatment, as well as samples derived from spent coffee grounds, showed the formation of hybrid compounds composed by CQA molecules covalently linked to a variable number of sugar residues. Moreover, the results obtained from the mixture containing Man3 and 5-CQA showed that CQA acts as catalyst of transglycosylation reactions. On the other hand, in the model mixtures containing a peptide, even if containing 5-CQA and subjected to the same treatment, it was observed a decrease in the extent of transglycosylation reactions. This outcome can explain the low extent of non-enzymatic transglycosylation reactions during roasting in coffee bean regions enriched in proteins, although polysaccharides are the major components of the coffee beans. The decrease of transglycosylation reactions in the presence of peptides/proteins can be related with the preferential reactivity of reducing residues with the amino groups of peptides/proteins by Maillard reaction, decreasing the number of reducing residues available to be directly involved in the transglycosylation reactions. In addition to the compounds already described, a diversity of other compounds were formed from model systems, namely dehydrated derivatives formed during dry thermal treatment. In conclusion, the identification of the structural modifications in coffee polysaccharides promoted by roasting pave the way to the understanding of the mechanisms of formation of melanoidins and structure-activity relationship of these compounds.

Seed loss in canola (Brassica napus, Brassica rapa and Brassica juncea) leads to considerable loss of revenue and dispersal of canola seeds into the soil seedbank. Once canola seeds enter the soil seedbank a portion can become secondarily dormant and persist for many years creating volunteer weed problems in following crops. Reducing canola seed loss and seedbank persistence can be an important strategy to reduce the incidence of volunteer weeds. The primary hypothesis of this research was that canola seedbank addition and dormancy induction in the seed are affected by genotype and harvest method. To test this hypothesis, three studies were conducted with the following objectives: i) to determine canola seedbank addition from windrowing and direct-harvesting operations on commercial farms in western Canada, ii) to determine agronomic- and harvest-related factors that may increase seed loss in canola, iii) to determine the effect of stage of crop maturity at harvest on potential to develop seed dormancy in canola, iv) to evaluate canola genotypes and harvest methods to reduce canola seedbank addition. A total of 66 canola fields were surveyed across Saskatchewan in 2010 and 2011. Shattered seeds from these fields were sampled within 3 weeks of harvest by using a vacuum cleaner. Agronomic- and harvest-related data were collected for each field using questionnaires. In a separate small plot study the effects of harvest methods (windrowing and direct-harvesting) and pod sealant products (Pod-Stik® and Pod Ceal DC®) on seed loss in five canola genotypes (InVigor5440, RR45H26, InVigor5020, RR4362, and CL8571) were evaluated in 2010 and 2011. In both years, 6 harvest samples were collected weekly from InVigor5440 and InVigor5020 genotypes starting at early stage of crop maturity until harvest to assess the effect of seed maturity on dormancy induction. On commercial farms, the average seedbank addition was 5,821 viable seeds m-2, which was equivalent to 7.3% of the total seed yield. There was no difference in the reported yield and seedbank addition between windrowed and direct-harvested canola on commercial farms. But in the small plot study, windrowing resulted in higher seedbank addition. Higher seedbank addition was observed when the yield of canola was higher and when producers had a larger area seeded to canola. The observed seedbank addition was also higher in Roundup Ready genotypes and when a conventional combine harvester was used to harvest canola. Little primary dormancy and low potential to secondary dormancy induction was observed in InVigor5440 and InVigor5020 seeds at an early stage of crop maturity. But at full maturity seeds of both genotypes had no primary dormancy but showed high potential for secondary dormancy induction. This indicates that windrowing the evaluated genotypes at early stage of crop maturity lowered the potential for secondary dormancy induction. There were appreciable differences in seedbank addition among the evaluated canola genotypes but pod sealant products did not affect seed yield and seed shatter in canola. The results of this study suggest that canola seedbank addition can be minimized by growing genotypes having reduced seed loss and with the adoption of direct-harvesting operations.

碩士
國立成功大學
資源工程學系
103
In this study, raw materials talc (d50=6.4 μm), kaolinite (3.1 μm), and α-Al2O3 (253 nm) powders were weighted and mixed firstly with each other at a stoichiometric composition of cordierite. Assumed that the raw materials powders were forming agglomerates of stoichiometric cordierite composition, acting as the reaction units. The calculated reaction unit that composed of the raw materials powders of 1 talc particle, 10.88 kaolinite particles and 3672.55 α-Al2O3 particles then determined to be 10 μm. Furthermore, this research added cordierite powders acting as seeds with particle sizes (d50) of 2.5 (C2), 21.5 (C20), 44.3 μm (C40).The calculated mixing weight fractions of the three seed powders that will surround the 10 μm reaction units with single layer were 15, 30, 55 weight % (-15, -30, -55), respectively. Experiment was analyzed by DTA, XRD, XRF, SEM, PSD techniques. It was found that α-Al2O3 delayed disappearance with the fine seed additions, indicating that the reaction route for α-Al2O3 to form spinel that transforms to cordierite, subsequently is altered. In case of coarse seeds added, α-Al2O3 + enstatite → spinel + SiO2 occurred, while the fine seeds was added, mullite + 3 enstatite + 5/2 SiO2 → 3/2 cordierite occurred. Similarly, mullite diminished early, indicating that the two reaction routes for mullite : mullite + 3 enstatite → 3 spinel + 5 SiO2 by coarse seed addition, while mullite + 3 enstatite + 5/2 SiO2 → 3/2 cordierite by fine seed addition. Therefore, the spinel formation of coarser seed was more than finer. The result showed that α-Al2O3, enstatite, mullite and SiO2 will directly form that of cordierite at temperature about 1200oC. And the seeding effect increases with higher amounts of seed additions, especially for samples with finer seeds addition C2-30 ＆ C2-55. Seed particles that can reach single layer surrounding to reaction units, samples C2-15, C20-30, C40-55 will result in a higher amount of cordierite formation. And the effect increases with the finer seed additions, especially C2-15. Either insufficient amounts of seed addition or over-use of them gave the reduction in cordierite formation.

Natural, plant-based tannin antioxidants are capable of inhibiting lipid oxidation in ground beef and may be possible alternatives to industry synthetic and natural standards of BHA/BHT and rosemary extract, respectively. Ground beef was purchased on three different days, each defining a batch during study 1. Treatments, added based on meat weight, included a control, 0.2 percent rosemary (RM), 0.02 percent BHA/BHT, 0.5 percent Chardonnay grape seed flour (CG), 0.1 percent and 0.25 percent chestnut wood flour (CN), and 0.25 percent and 0.5 percent of four sorghum bran varieties: black (BS), black with tannin (BTS), white (WS), and high tannin (TS). Patties, formed in duplicate, were randomly designated as cooked or raw and by 0 to 5 day storage, and were aerobically stored at 4 degrees C. Cooked patties were analyzed using the TBARS method. Raw patties were analyzed for subjective and objective color, number of ingredient specks, and pH. In study 2, six treatments were chosen for sensory evaluation including a control, 0.2 percent RM, 0.02 percent BHA/BHT, 0.5 percent CG, 0.1 percent CN, and 0.5 percent BTS. Preparation, and raw and cooked analysis occurred similar to study 1. Additional patties were made for day 1 consumption by consumer panelists. In study 1, all treatments except 0.25 percent WS reduced TBARS values over time compared to 0.2 percent RM. Four treatments (0.5 percent BTS, 0.5 percent CG, 0.25 percent CN, and 0.1 percent CN) showed no significant increase in TBARS values over storage. BS and BTS yielded the lowest color space values (CIE L*, a*, and b*; P<0.0001). Ingredient specks were possible color measurement influences. In both studies antioxidant addition reduced TBARS values over time compared to the control (P<0.0001), and percent discoloration was highest in patties containing a sorghum treatment (P<0.0001). Patties containing 0.1 percent CN were significantly favored in terms of overall like (P<0.0002) and flavor like (P<0.0001). Patties containing 0.2 percent RM were ranked lowest in overall and flavor like, and ground beef-like bite. Patties containing 0.5 perent CG were least liked according to tenderness level (P<0.005). These results indicate that CG, CN, and certain varieties of sorghum bran can be added to pre-cooked ground beef products and provide better antioxidant protection than currently used ingredients of BHA/BHT and rosemary extract.

Reynoutria spp. rank among highly invasive taxa in the Czech Republic. Therefore, a considerable effort is focused on its eradication. This is usually done by application of non- selective herbicide based on glyphosate. However, only little is known about the spontaneous recovery of the native vegetation after the eradication, as well as whether the restoration can be facilitated by additional management. In my master thesis I (i) describe the process of restoration after Reynoutria spp. eradication, (ii) evaluate the influence of factors which could potentially inhibit the succession (such as glyphosate, allelopathy, changes in soil conditions due to Reynoutria spp. invasion), and (iii) evaluate the influence of native-species seed addition on establishment of target plant communities. The process of vegetation recovery was followed on 17 sites in a forest and in ruderal forest-free area from 2007 to 2010. Over the three years of the study, the sites in the forest- free area were covered by diverse vegetation, secondary succession on sites in a forest progressed more slowly. Any soil changes were detected. The process of succession was limited probably because a dead biomass was left on the sites after the eradication. The seed addition was also not crucial for the restoration of plant communitites.

Seed addition experiment was conducted on the moisture gradient with aim to demonstrate that many species not accounted by current measures of species pools in a site should be included because they are in fact able to establish successfully if biotic filter is removed. Transplant experiment was established to compare the sensitivity of seedling recruitment and survival of transplants in the field. Recruitment of seedlings in field was observed and compared with germination of seeds under different chilling treatments in laboratory.

Native forbs contribute significantly to grassland species diversity, with flow-on benefits for habitat value (eg. for birds, reptiles, invertebrates), ecosystem services (eg. pollinator diversity, pest control) and resistance to invasion by exotic plants. Humans have modified grasslands around the world with agricultural land use and/or poor management, often resulting in significant loss of native forb diversity. Research over several decades identifies elevated soil nutrients, exotic species and changed disturbance regimes as threats to grassland forb diversity, but despite this knowledge, forb restoration remains difficult and forb diversity in temperate grasslands remains low. My research aimed to further our understanding of forb ecology and the challenges of maintaining and restoring native forb diversity, focusing on grassy ecosystems in south-eastern Australia. The research was predominantly conducted within an area of White Box – Yellow Box – Blakely’s Red Gum woodland and derived grassland in a nature reserve in Canberra, in south-eastern Australia. This ecosystem is listed as critically endangered, largely on the basis of lost ground-layer diversity. This thesis includes an introduction (or context statement) outlining my research program and how it contributes to the literature, three chapters describing empirical research projects I conducted for the PhD, and a final chapter representing a synthesis of my results in the form of a conceptual model with management recommendations. Chapters two to five are written as manuscripts submitted or accepted for publication in scientific journals. Chapter 2: A comparison of native and exotic forb responses to eight variables that influence forb habitat quality in temperate grasslands The second chapter (submitted) is based on a survey of the study area, in which I collected data on ground-layer vegetation, soil chemistry and soil physical properties, and topography. I analysed forb responses to eight environmental variables representing landscape, soil, and vegetation biomass. I identified thresholds of grass cover, litter cover and soil phosphorus above which native forbs are much less likely to occur than exotic forbs. Chapter 3: Fine-scale variables associated with the presence of native forbs in natural temperate grassland The third chapter (submitted) is based on a case-control survey designed to determine the fine-scale variables associated with the presence/absence of individual native forbs. Consistent with the results from our other research, I identified that dead biomass cover, grass cover, and exotic forb cover were negatively associated with the odds that a native forb would be present in temperate grassland. Chapter 4: Seed addition and biomass removal key to restoring native forbs in degraded temperate grassland The fourth chapter (manuscript accepted by Applied Vegetation Science) is based on a controlled field experiment designed to test hypotheses arising from our previous results. I applied treatments that reduce above ground biomass (grass tussocks, leaf litter, and exotic species) and added seed of 14 native forb species. Native and exotic forb seedlings were both negatively affected by living grass cover, however, native forb seedlings were more restricted by litter than exotic forb seedlings. Our results suggest that naturally occurring seed in disturbed grassland is likely to be inadequate for restoration. Chapter 5: Maintaining or restoring forb diversity in temperate grasslands The fifth chapter (submitted) provides a synthesis of our PhD results as a conceptual model of habitat suitability for native forbs in relation to available phosphorus and biomass cover. I propose some thresholds for these variables and discuss appropriate restoration actions. This chapter targets practitioners aiming to conserve native diversity in temperate grasslands.

Invasive exotic species threaten biodiversity and ecosystem functions globally, creating need for and encumbering ecological restoration. When restoring exotic plant-dominated ecosystems, reinvasion pressure is the rate of new exotic recruitment following mature exotic removal. It can vary broadly among similarly invaded habitats and is crucial to restoration outcomes and costs, but is difficult to predict and poorly understood. Initial results from the experimental restoration of a wetland dominated by Triadica sebifera led us to develop the ‘outgrow the stress’ hypothesis. It holds: (1) Variation in reinvasion pressure is driven by differences in propagule abundance and spatiotemporal availability of realized recruitment windows, which are defined by abiotic conditions and biotic interactions. (2) Differences in reinvasion pressure become masked by exotic dominance when increases in niche breadth during development enable exotic persistence across sites where recruitment windows range from frequent to episodic. We validated this hypothesis. First, we used greenhouse and field experiments to quantify Triadica’s moisture niche early in development. By two months post-germination, seedling tolerances broadened to include conditions unsuitable for germination. This clearly demonstrated a rapid ontogenetic niche expansion, which could decouple mature Triadica density and average reinvasion pressure. Second, we used a greenhouse mesocosm experiment to quantify how recruitment window duration, competition and fertility impacted population-level Triadica establishment in stressful environments. As ‘outgrow the stress’ predicts, longer windows increased Triadica success and multi-factor interactions were common, with competition and fertility effects varying among environmental contexts. Third, we substantiated predictions of ‘outgrow the stress’ regarding propagule availability and soil moisture by manipulating these in a multi-site field experiment spanning eleven experimental restorations of Triadica-dominated habitats along a moisture gradient. Triadica reinvasion pressure varied broadly among sites but correlated with moisture and fertility. Propagule availability drove reinvasion in favorable environments, but availability of suitable conditions trumped propagules in extreme environments. Competition reduced Triadica performance and sometimes survival. Triadica prevalence reduced native plant prevalence. Six restorations require minimal Triadica management for success. This work advances our understanding and enables better predictions of reinvasion pressure and invasions in general. Accurate predictions enhance restoration efficiency by informing site selection and optimal management strategies.

This major thesis expands the issue of the bachelor thesis "The issue of raising laying hens considering on introduction of enriched cages" and adds new knowledge relating to the topic feed rations and their influence on the final production. The theoretical part of the thesis analyses the basic theoretical concepts cohering with this topic, focused on creating a comprehensive overview of the structure and quality of the eggs, the basic ingredients in the feed rations, qualitative parameters of grapes as the modified additive provided by us and last but not least there is processed the recent overview of the current state of large-scale farmers in the Czech republic. The practical part of the thesis aims to test the effect of the proposed feed with an additive in the form of the crushed grape seeds, on the strength of the eggshell, by homogeneous samples of the breeds through from us proposed measuring instrument. Subsequently, a statistical evaluation of measured results is realized. In conclusion, the consideration is extended to the economic evaluation of costs and profits in case of the implementation of the suggested feed ration into practice in order to quantify the difference compared to the commonly used feed ration.