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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Saccharomyces cerevisiae em milho armazenado e o efeito na redução de aflatoxicoses. / Saccharomyces cerevisiae in stored corn and the reduction effect of aflatoxicosis.

Baptista, Antonio Sampaio 24 April 2001 (has links)
O aproveitamento de células vivas de leveduras - Saccharomyces cerevisiae - como probiótico, e, componentes extraídos da parede celular desta levedura, como aditivos, para desejadas funções, têm sido objeto de interesse cada vez maior, pelos resultados promissores até então obtidos e, concomitantemente, pelo excedente de biomassa de leveduras gerado pela indústria de etanol e cerveja no Brasil. Por estes motivos, foram conduzidos dois experimentos, um com o objetivo de investigar a possibilidade de utilizar o milho como um veículo alternativo para a levedura S. cerevisiae - como probiótico, e outro, com o propósito de estudar a capacidade de reduzir danos promovidos pelas aflatoxinas, das leveduras vivas, das termolisadas e mananoligossacarídeos. O primeiro experimento foi montando em um arranjo fatorial 2x2x5, constituído de duas concentrações de leveduras (1 e 2%), grãos de milho com dois teores de umidade (16 e 20%) e 5 períodos de armazenamento (0, 15, 30, 90 e 110 dias), distribuído ao acaso, com 4 repetições. O outro estudo, foi um bioensaio, conduzido durante 28 dias, com ratos Wistar, em um experimento com delineamento inteiramente casualizado, com 7 tratamentos e 5 repetições. A concentração de células aplicadas nos grãos de milho não influenciou a viabilidade das leveduras durante o armazenamento. A umidade do substrato interferiu no desenvolvimento da viabilidade, e que, em substratos com maiores teores de umidade foram observadas menores médias de viabilidade durante o armazenamento. A viabilidade das células de leveduras permaneceu constante por 30 dias e aos 90 dias em armazenamento foram observadas reduções no número de células viáveis. As leveduras apresentaram viabilidade de 70% aos 110 dias em armazenamento. A inoculação de leveduras vivas em grãos de milho, visando a sua utilização como probiótico, é uma técnica viável. Os tratamentos com levedura termolisada e mananoligossacarídeos não foram capazes de reduzir os danos promovidos pelas aflatoxinas em nível de hepatócitos. As leveduras vivas foram capazes de reduzir os danos promovidos pelas aflatoxinas em nível celular. / The utilization of live cells of yeasts - Saccharomyces cerevisiae - as probiotic, and, extracted components of the cellular wall of this yeast, as addictive, to desired functions, have been object of interest, due the promising results until then obtained and, simultaneously, for the excess of biomass of yeasts generated by the etanol and beer industry in Brazil. For these reasons, two experiments were led, one with the objective of investigate the possibility to use the corn as an alternative vehicle for the yeast S. cerevisiae - as probiotic, and other, with the purpose of studying the capacity to reduce damages promoted by the aflatoxins of the live yeasts, termoliseds and mananoligossacarides. The first experiment was mounted in a factorial arrangement 2x2x5, constituted of two concentrations of yeasts (1 and 2%), corn grains with two moisture contents (16 and 20%) and 5 storage periods (0, 15, 30, 90 and 110 days), random arrangement, with 4 replications. The other study, was a bioassay, led during 28 days, with rats Wistar, in completely randomzed desing, with 7 treatments and 5 repetitions. The concentration of applied cells in the corn grains did not influence the viability of the yeasts during the storage. The moisture of the substrate interfered in the development of the viability, and that in substrate with bigger moisture contents smaller viability averages were observed during the storage. The viability of the cells of yeasts remains constant for 30 days and to the 90 days in storage reductions were observed in the number of viable cells. The yeasts presented viability from 70% to the 110 days in storage. The inoculation of live yeasts in corn grains, aiming its use as probiotic, is a viable technique. The treatments with yeast termolised and mananoligossacarídes were not capable of reducing the damages promoted by the aflatoxins in hepatocites level. The live yeasts were capable to reduce the damages caused by the aflatoxins in cellular level.
2

Saccharomyces cerevisiae em milho armazenado e o efeito na redução de aflatoxicoses. / Saccharomyces cerevisiae in stored corn and the reduction effect of aflatoxicosis.

Antonio Sampaio Baptista 24 April 2001 (has links)
O aproveitamento de células vivas de leveduras – Saccharomyces cerevisiae – como probiótico, e, componentes extraídos da parede celular desta levedura, como aditivos, para desejadas funções, têm sido objeto de interesse cada vez maior, pelos resultados promissores até então obtidos e, concomitantemente, pelo excedente de biomassa de leveduras gerado pela indústria de etanol e cerveja no Brasil. Por estes motivos, foram conduzidos dois experimentos, um com o objetivo de investigar a possibilidade de utilizar o milho como um veículo alternativo para a levedura S. cerevisiae – como probiótico, e outro, com o propósito de estudar a capacidade de reduzir danos promovidos pelas aflatoxinas, das leveduras vivas, das termolisadas e mananoligossacarídeos. O primeiro experimento foi montando em um arranjo fatorial 2x2x5, constituído de duas concentrações de leveduras (1 e 2%), grãos de milho com dois teores de umidade (16 e 20%) e 5 períodos de armazenamento (0, 15, 30, 90 e 110 dias), distribuído ao acaso, com 4 repetições. O outro estudo, foi um bioensaio, conduzido durante 28 dias, com ratos Wistar, em um experimento com delineamento inteiramente casualizado, com 7 tratamentos e 5 repetições. A concentração de células aplicadas nos grãos de milho não influenciou a viabilidade das leveduras durante o armazenamento. A umidade do substrato interferiu no desenvolvimento da viabilidade, e que, em substratos com maiores teores de umidade foram observadas menores médias de viabilidade durante o armazenamento. A viabilidade das células de leveduras permaneceu constante por 30 dias e aos 90 dias em armazenamento foram observadas reduções no número de células viáveis. As leveduras apresentaram viabilidade de 70% aos 110 dias em armazenamento. A inoculação de leveduras vivas em grãos de milho, visando a sua utilização como probiótico, é uma técnica viável. Os tratamentos com levedura termolisada e mananoligossacarídeos não foram capazes de reduzir os danos promovidos pelas aflatoxinas em nível de hepatócitos. As leveduras vivas foram capazes de reduzir os danos promovidos pelas aflatoxinas em nível celular. / The utilization of live cells of yeasts - Saccharomyces cerevisiae - as probiotic, and, extracted components of the cellular wall of this yeast, as addictive, to desired functions, have been object of interest, due the promising results until then obtained and, simultaneously, for the excess of biomass of yeasts generated by the etanol and beer industry in Brazil. For these reasons, two experiments were led, one with the objective of investigate the possibility to use the corn as an alternative vehicle for the yeast S. cerevisiae - as probiotic, and other, with the purpose of studying the capacity to reduce damages promoted by the aflatoxins of the live yeasts, termoliseds and mananoligossacarides. The first experiment was mounted in a factorial arrangement 2x2x5, constituted of two concentrations of yeasts (1 and 2%), corn grains with two moisture contents (16 and 20%) and 5 storage periods (0, 15, 30, 90 and 110 days), random arrangement, with 4 replications. The other study, was a bioassay, led during 28 days, with rats Wistar, in completely randomzed desing, with 7 treatments and 5 repetitions. The concentration of applied cells in the corn grains did not influence the viability of the yeasts during the storage. The moisture of the substrate interfered in the development of the viability, and that in substrate with bigger moisture contents smaller viability averages were observed during the storage. The viability of the cells of yeasts remains constant for 30 days and to the 90 days in storage reductions were observed in the number of viable cells. The yeasts presented viability from 70% to the 110 days in storage. The inoculation of live yeasts in corn grains, aiming its use as probiotic, is a viable technique. The treatments with yeast termolised and mananoligossacarídes were not capable of reducing the damages promoted by the aflatoxins in hepatocites level. The live yeasts were capable to reduce the damages caused by the aflatoxins in cellular level.
3

Effect of benzylglucosinolate on signaling pathways associated with type 2 diabetes prevention

Guzman-Perez, Valentina January 2014 (has links)
Type 2 diabetes (T2D) is a health problem throughout the world. In 2010, there were nearly 230 million individuals with diabetes worldwide and it is estimated that in the economically advanced countries the cases will increase about 50% in the next twenty years. Insulin resistance is one of major features in T2D, which is also a risk factor for metabolic and cardiovascular complications. Epidemiological and animal studies have shown that the consumption of vegetables and fruits can delay or prevent the development of the disease, although the underlying mechanisms of these effects are still unclear. Brassica species such as broccoli (Brassica oleracea var. italica) and nasturtium (Tropaeolum majus) possess high content of bioactive phytochemicals, e.g. nitrogen sulfur compounds (glucosinolates and isothiocyanates) and polyphenols largely associated with the prevention of cancer. Isothiocyanates (ITCs) display their anti-carcinogenic potential by inducing detoxicating phase II enzymes and increasing glutathione (GSH) levels in tissues. In T2D diabetes an increase in gluconeogenesis and triglyceride synthesis, and a reduction in fatty acid oxidation accompanied by the presence of reactive oxygen species (ROS) are observed; altogether is the result of an inappropriate response to insulin. Forkhead box O (FOXO) transcription factors play a crucial role in the regulation of insulin effects on gene expression and metabolism, and alterations in FOXO function could contribute to metabolic disorders in diabetes. In this study using stably transfected human osteosarcoma cells (U-2 OS) with constitutive expression of FOXO1 protein labeled with GFP (green fluorescent protein) and human hepatoma cells HepG2 cell cultures, the ability of benzylisothiocyanate (BITC) deriving from benzylglucosinolate, extracted from nasturtium to modulate, i) the insulin-signaling pathway, ii) the intracellular localization of FOXO1 and iii) the expression of proteins involved in glucose metabolism, ROS detoxification, cell cycle arrest and DNA repair was evaluated. BITC promoted oxidative stress and in response to that induced FOXO1 translocation from cytoplasm into the nucleus antagonizing the insulin effect. BITC stimulus was able to down-regulate gluconeogenic enzymes, which can be considered as an anti-diabetic effect; to promote antioxidant resistance expressed by the up-regulation in manganese superoxide dismutase (MnSOD) and detoxification enzymes; to modulate autophagy by induction of BECLIN1 and down-regulation of the mammalian target of rapamycin complex 1 (mTORC1) pathway; and to promote cell cycle arrest and DNA damage repair by up-regulation of the cyclin-dependent kinase inhibitor (p21CIP) and Growth Arrest / DNA Damage Repair (GADD45). Except for the nuclear factor (erythroid derived)-like2 (NRF2) and its influence in the detoxification enzymes gene expression, all the observed effects were independent from FOXO1, protein kinase B (AKT/PKB) and NAD-dependent deacetylase sirtuin-1 (SIRT1). The current study provides evidence that besides of the anticarcinogenic potential, isothiocyanates might have a role in T2D prevention. BITC stimulus mimics the fasting state, in which insulin signaling is not triggered and FOXO proteins remain in the nucleus modulating gene expression of their target genes, with the advantage of a down-regulation of gluconeogenesis instead of its increase. These effects suggest that BITC might be considered as a promising substance in the prevention or treatment of T2D, therefore the factors behind of its modulatory effects need further investigation. / Diabetes mellitus Typ 2 stellt auf der ganzen Welt ein Gesundheitsproblem dar. Im Jahr 2010 waren annähernd 230 Millionen Personen weltweit an Diabetes erkrankt und innerhalb der nächsten 20 Jahre wird in industrialisierten Ländern eine Steigerung der Fälle um 50% erwartet. Eines der Hauptmerkmale des Typ 2 Diabetes ist die Insulinresistenz, die auch als Risikofaktor für metabolische und kardio-vaskuläre Komplikationen gilt. Epidemiologische Studien und Tierversuche haben ergeben, dass durch Verzehr von Gemüse und Obst eine Prävention oder Verzögerung der Entwicklung dieser Krankheit erreicht werden kann, jedoch sind die zugrunde liegenden Mechanismen dieser Effekte noch nicht aufgeklärt. Brassica Spezies wie Broccoli (Brassica oleracea var. italica) und Nasturtium (Tropaeolum majus) enthalten einen hohen Anteil an bioaktiven Pflanzen-inhaltsstoffen, wie z. B. stickstoff- und schwefelhaltige Verbindungen (Glukosinolate und Isothiocyanate) und Polyphenole, die bisher hauptsächlich mit der Prävention von Krebs assoziiert wurden. Isothiocyanate (ITCs) erreichen ihr antikanzerogenes Potential durch die Induktion von entgiftenden Phase II Enzymen und eine Anhebung der Glutathion (GSH)-Spiegel im Gewebe. Diabetes Typ2 geht einher mit einem Anstieg der Glukoneogenese und Triglycerid-Synthese, sowie einer Reduktion der Fettsäure-Oxidation in Verbindung mit erhöhten Spiegeln an reaktiven Sauerstoffspezies (ROS) insgesamt als Resultat einer unangemessenen Insulinantwort. Forkhead box O (FOXO) Transkriptionsfaktoren spielen eine wesentliche Rolle in der Regulation der Insulineffekte in Bezug auf die vermittelte Genexpression und den Metabolismus, wobei Veränderungen in der Funktion von FOXO zu metabolischen Entgleisungen im Diabetes beitragen können. In dieser Studie wurde unter Verwendung von stabil transfizierten humanen Osteosarkoma-Zellen (U-2 OS) mit konstitutiver Expression von GFP (grün fluoreszierendes Protein)-markiertem FOXO1 und humanen Hepatoma-Zellen (HepG2) die Wirkung von Benzylisothiocyanat (BITC), dessen Vorstufe Benzylglukosinolat aus Nasturtium isoliert wurde, in Zellkulturen evaluiert wie Modulationen der i) Insulin-Signal-Kaskade, ii) intrazellulären Lokalisation von FOXO1 und iii) Expression beteiligter Proteine am Glucose Metabolismus, der ROS Detoxifikation, Zellzyklus-Fixierung und DNA-Reparatur. BITC erzeugte oxidativen Stress und induzierte als Antwort darauf eine Translokation von FOXO1 aus dem Zytoplasma in den Zellkern antagonisierend zum Insulin-Effekt. Eine Stimultion mit BITC war in der Lage, die Expression von Enzymen der Gluconeogenese herunter zu regulieren, was als antidiabetogener Effekt betrachtet werden kann, eine antioxidative Resistenz durch Induktion der Mangan-Superoxid-Dismutase (MnSOD) und entgiftender Enzyme zu erzeugen, Autophagie zu modulieren durch Induktion von BECLIN1 und Herunterregulation des „mammalian target of rapamycin complex1 (mTORC1)-Stoffwechselwegs, den Zellzyklus zu fixieren und DNA-Reparatur zu induzieren durch Hochregulation des Cyclin- abhängigen Kinase- Inhibitors p21CIP und GADD45 (growth arrest and DNA damage repair). Mit Ausnahme des nuklearen Faktors (erythroid derived)-like2 (NRF2) und dessen Einfluss auf die Genexpression von Entgiftungsenzymen waren alle beobachteten Effekte unabhängig von FOXO1, Proteinkinase B (PKB/AKT) und der NAD-abhängigen Deacetylase Sirtuin-1 (SIRT1). Die gegenwärtige Studie liefert Anhaltspunkte dafür, dass Isothiocayanate neben dem antikanzerogenen Potential eine Rolle bei der Prävention von Typ 2 Diabetes spielen könnten. BITC-Stimulationen ahmen einen Fastenzustand nach, in dem kein Insulin-Signal ausgelöst wird, FOXO Proteine im Zellkern verbleiben und die Expression von Target-Genen modulieren, mit dem Vorteil einer Herunterregulation der Glukoneogenese anstelle seiner Zunahme. Diese Effekte legen nahe, dass BITC als vielversprechende Substanz zur Prävention und Behandlung von Typ 2 Diabetes angesehen werden könnte. Deshalb benötigen die Faktoren, die dessen modulatorische Effekte hervorrufen, weitere Untersuchungen.

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