No description available.

The major serine proteinase inhibitors Kunitz and Bowman-Birk-type trypsin are key anti-nutrients responsible for the low nutritional value of raw soy cake, the by product of oil expression from soybean. Traditionally, proteinase inhibitors are eliminated from soy cake through intensive heating, which is highly costly. The long term goal is to generate soybean seeds devoid of trypsin inhibitors through tissue culture and genetic modification of soybean. The RNAi technology has been selected in this study as a technique for down-regulation or silencing these two major serine trypsin inhibitors. Conserved regions, which have been identified by searching NCBI and EMBL database, were targeted for down regulation. Seed specific promoters were also isolated to drive the expression of hairpin constructs designed to down-regulate selected conserved regions of the inhibitors in soybean seeds. RNAi silencing constructs were designed for use in soybean transformation. Ultimately, a tissue culture and transformation protocol for a local soybean variety PAN 512 was established for transformation with two designed RNAi constructs. Suitability of selected promoters was tested by attaching promoters to the gus gene and evaluating specificity of seed expression after soybean transformation using the Agrobacterium tumefaciens strain EHA101. Future work will focus on further optimisation of the transformation protocol and generation of transformed plants carrying the designed silencing vectors. Copyright / Dissertation (MSc)--University of Pretoria, 2010. / Plant Science / unrestricted

No description available.

Note:

A existência de uma família gênica diversa de serino proteinases em Lepidóptera sugere que essas proteinases desempenham um papel importante na adaptação desses insetos à presença de inibidores de proteinases vegetais. Essas enzimas têm se revelado estarem envolvidas no processo digestivo de larvas de insetos. Larvas de Spodoptera frugiperda foram alimentadas com uma dieta suplementada com inibidor de proteinase de soja (IPS) e a expressão gênica de proteinases intestinais foi avaliada através de PCR em tempo real. Análises de transcrição anteriores mostraram a existência de dois grupos de serino proteinases: um grupo de genes constitutivamente expressos em larvas controle que é induzido pela dieta contendo IPS e um segundo grupo que está ausente no controle, mas que é também induzido por uma dieta rica em IPS. No presente trabalho foi observado um terceiro grupo de proteinases que não são nem induzidas nem reprimidas pela presença do IPS na dieta. Essa observação sugere que a adaptação de S. frugiperda ao IPS envolve a síntese de novas proteinases, a indução de enzimas preexistentes e ainda um terceiro grupo insensível à presença dos inibidores. Proteinases dos intestinos de larvas crescidas em dieta com IPS mostraram insensibilidade ao inibidor. As proteinases também foram insensíveis quando a atividade foi verificada com um inibidor de proteinases de amplo espectrum. Os resultados aqui apresentados propõem que a adaptação de S. frugiperda ao IPS segue uma estratégia generalizada, baseada na indução geral de um grande grupo de endoproteinases. / The existence of a diverse serine proteinase gene family in lepidopteran insects has suggested its significant role in the insect adaptation to plant proteinase inhibitors. These enzymes have been shown to be involved in the proteolytic digestion process of insect larvae. Spodoptera frugiperda larvae were fed on a diet supplemented with soybean proteinase inhibitor (SPI) and the gene expression of intestinal proteinases was evaluated by real time PCR. Previous transcription analyses found two groups of intestinal serine proteinases: one group of genes constitutively expressed in the control larvae that is induced by the SPI-containing diet during the experiment, and a second group that is absent in the control but also induced by the SPI rich diet. Herein was observed a third group of proteinases that are neither induced nor repressed by the presence of SPI in the diet. This observation suggests that adaptation of S. frugiperda to SPI involves de novo synthesis, up regulation of existing enzymes and that there is a third group insensitive to the presence of the inhibitors. Proteinases from intestines of larvae reared on a diet with SPI showed insensitivity to the inhibitor. The proteinases were also insensitive when the activity was checked with a broad-spectrum potato proteinase inhibitor. The results here presented propose that adaptation of S. frugiperda to SPI follows a \"shotgun\" approach, based on a general up regulation of a large set of endoproteinases.

by Ricardo Wong Chi Ho. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2000. / Includes bibliographical references (leaves 128-138). / Abstracts in English and Chinese. / Acknowledgments --- p.i / Abstract --- p.ii / 論文摘要 --- p.iv / Table of Contents --- p.vi / List of Figures --- p.xi / List of Tables --- p.xiii / List of Abbreviations --- p.xiv / Chapter Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Overview of Serine Protease Inhibitors --- p.1 / Chapter 1.2 --- Classification of Serine Protease Inhibitors --- p.2 / Chapter 1.2.1 --- Kunitz Type Serine Protease Inhibitors --- p.7 / Chapter 1.2.2 --- Bowman-Birk Type Serine Protease Inhibitors --- p.11 / Chapter 1.2.3 --- Squash Type Serine Protease Inhibitors --- p.16 / Chapter 1.3 --- Role of Serine Protease Inhibitors in Plants --- p.20 / Chapter 1.4 --- Nutritional Fact of Serine Protease Inhibitors --- p.22 / Chapter 1.5 --- Possible Applications of Serine Protease Inhibitors --- p.25 / Chapter 1.5.1 --- Medical Applications --- p.25 / Chapter 1.5.2 --- Agricultural Applications --- p.29 / Chapter 1.6 --- Rationale of the Present Study --- p.31 / Chapter Chapter 2 --- Screening of Seeds for Inhibitory Activities Against Serine Proteases --- p.33 / Chapter 2.1 --- Introduction --- p.33 / Chapter 2.2 --- Materials and Methods --- p.37 / Chapter 2.2.1 --- Materials --- p.37 / Chapter 2.2.2 --- Extraction Method --- p.37 / Chapter 2.2.3 --- Assays for Proteases Inhibitory Activities --- p.38 / Chapter 2.2.3.1 --- Assay for Chymotrypsin Activity --- p.38 / Chapter 2.2.3.2 --- Assay for Trypsin Activity --- p.38 / Chapter 2.2.3.3 --- Assay for Elastase Activity --- p.39 / Chapter 2.2.3.4 --- Assay for Subtilisin Activity --- p.39 / Chapter 2.2.3.5 --- Assays for Protease Inhibitory Activities --- p.40 / Chapter 2.2.4 --- Determination of Protein Concentration --- p.41 / Chapter 2.3 --- Results --- p.42 / Chapter 2.3.1 --- Extraction --- p.42 / Chapter 2.3.2 --- Serine Proteases Inhibitory Activities --- p.42 / Chapter 2.4 --- Discussion --- p.47 / Chapter Chapter 3 --- Isolation of Chymotrypsin Inhibitor and Trypsin Inhibitors from Momordica cochinchinensis Seeds --- p.49 / Chapter 3.1 --- Introduction --- p.49 / Chapter 3.2 --- Materials and Methods --- p.56 / Chapter 3.2.1 --- Materials --- p.56 / Chapter 3.2.2 --- Protein Extraction --- p.57 / Chapter 3.2.3 --- SP-Sepharose Chromatography --- p.57 / Chapter 3.2.4 --- Reversed Phase High Pressure Liquid Chromatography --- p.58 / Chapter 3.2.5 --- Assays for Chymotrypsin and Trypsin Inhibitory Activities --- p.60 / Chapter 3.2.6 --- Titration of Chymotrypsin --- p.61 / Chapter 3.2.7 --- Tricine Sodium Dodecyl Sulfate Polyacrylamide Gel Electrophoresis --- p.62 / Chapter 3.2.8 --- Coupling of Trypsin-Sepharose 4B Affinity Column --- p.63 / Chapter 3.2.9 --- Affinity Chromatography on Trypsin-Sepharose 4B --- p.64 / Chapter 3.3 --- Results --- p.65 / Chapter 3.3.1 --- SP-Sepharose Chromatography --- p.65 / Chapter 3.3.2 --- Reversed Phase High Pressure Liquid Chromatography --- p.67 / Chapter 3.3.3 --- Summary of Purification --- p.71 / Chapter 3.3.4 --- Titration of Chymotrypsin --- p.74 / Chapter 3.3.5 --- Tricine Sodium Dodecyl Sulfate Polyacrylamide Gel Electrophoresis --- p.74 / Chapter 3.3.6 --- Affinity Chromatography on Trypsin-Sepharose 4B --- p.78 / Chapter 3.4 --- Discussion --- p.81 / Chapter Chapter 4 --- Characterization of Chymotrypsin Inhibitor and Trypsin Inhibitors --- p.88 / Chapter 4.1 --- Introduction --- p.88 / Chapter 4.2 --- Materials and Methods --- p.90 / Chapter 4.2.1 --- Materials --- p.90 / Chapter 4.2.2 --- Determination of Molecular Weight --- p.90 / Chapter 4.2.3 --- Amino Acid Sequence Analysis --- p.91 / Chapter 4.2.4 --- Surface Plasmon Resonance Measurement --- p.92 / Chapter 4.2.4.1 --- Immobilization of Ligands on the Surface of Optical Biosensors --- p.92 / Chapter 4.2.4.2 --- Determination of Kinetics Constants --- p.93 / Chapter 4.2.4.3 --- pH Dependence of the Inhibition by Chymotrypsin Inhibitor --- p.93 / Chapter 4.2.4.4 --- Data Analysis --- p.94 / Chapter 4.2.5 --- Effect of Chymotrypsin Inhibitor on the Estereolytic Activity and Proteolytic Activity of Chymotrypsin --- p.95 / Chapter 4.2.6 --- Specificities of the Inhibitors % --- p.96 / Chapter 4.2.7 --- Binding Ratio of CI to Different Proteases --- p.97 / Chapter 4.2.8 --- Effects of the Proteases on Their Corresponding Inhibitors --- p.97 / Chapter 4.2.8.1 --- Tricine Sodium Dodecyl Sulfate Polyacrylamide Gel Electrophoresis --- p.97 / Chapter 4.2.8.2 --- Assay for Chymotrypsin Inhibitory Activity --- p.98 / Chapter 4.3 --- Results --- p.99 / Chapter 4.3.1 --- Molecular Weight of the Inhibitors --- p.99 / Chapter 4.3.2 --- N-terminal Amino Acid Sequence --- p.99 / Chapter 4.3.3 --- Surface Plasmon Resonance Measurement --- p.102 / Chapter 4.3.3.1 --- Kinetics of Chymotrypsin Inhibitor --- p.102 / Chapter 4.3.3.2 --- Kinetics of Trypsin Inhibitors --- p.106 / Chapter 4.3.3.3 --- pH Dependence of the Inhibition by Chymotrypsin Inhibitor --- p.106 / Chapter 4.3.4 --- Effect of Chymotrypsin Inhibitor on the Estereolytic Activity and Proteolytic Activity of Chymotrypsin --- p.106 / Chapter 4.3.5 --- Specificities of the Inhibitors --- p.110 / Chapter 4.3.6 --- Binding Ratio of CI to Different Proteases --- p.112 / Chapter 4.3.7 --- Effects of the Proteases on Their Corresponding Inhibitors --- p.112 / Chapter 4.4 --- Discussion --- p.119 / Chapter Chapter 5 --- Conclusion --- p.125 / References --- p.128

La mucoviscidose est une maladie génétique caractérisée par une obstruction des voies respiratoires, des infections et une inflammation pulmonaire résultant du recrutement massif de neutrophiles qui sécrètent des protéases : l’élastase, la protéase 3 et la cathepsine G. Ces protéases peuvent être sécrétées selon deux voies, la dégranulation ou la sécrétion de NETs (Neutrophil Extracellular Traps), qui sont des fibres de chromatine auxquelles elles sont associées et décrites comme des structures antimicrobiennes. Dans le milieu extracellulaire, la dérégulation du contrôle de l’activité des protéases par leurs inhibiteurs conduit à la dégradation progressive du tissu pulmonaire. Nous avons montré que cette dérégulation était modulée par l’interaction des protéases avec l’ADN présent dans les sécrétions bronchiques des patients et que le ciblage de ces protéases par des inhibiteurs exogènes pouvait être amélioré in vitro par de la DNase ou de la polylysine qui compacte l’ADN. Ce polypeptide est également bactéricide vis-à-vis des pathogènes majeurs de la mucoviscidose, S. aureus et P. aeruginosa. Nos travaux montrent également que les NETs sont sécrétés dans les poumons des patients où ils constituent un réservoir de protéases actives potentiellement délétère et n’ont pas d’effet bactéricide vis-à-vis de S. aureus et P. aeruginosa. Nos travaux montrent que les voies de signalisation conduisant à la sécrétion des NETs varient selon le stimulus, générant des structures aux propriétés différentes. / Cystic fibrosis (CF) is a hereditary disease characterized by the obstruction of the airways, infections and a chronic lung inflammation due to a massive recruitment of neutrophils that secrete proteases: the elastase, the proteinase 3 and the cathepsin G. These proteases can be secreted by two mechanisms, namely degranulation and the secretion of NETs (Neutrophil Extracellular Traps), which are chromatin fibers to which they are bound and that have been described as antimicrobial structures. In the extracellular environment, the dysregulation of these proteases control by their inhibitors leads to progressive lung tissue degradation. We have shown that this dysregulation was influenced by the interaction of the proteases with the DNA found in the lung secretions of CF patients and that targeting these proteases with exogenous inhibitors could be improved in vitro by DNase or polylysine, which compacts DNA. This polypeptide also presents a bactericidal effect towards the major CF-associated pathogens, S. aureus and P. aeruginosa. Our work also shows that NETs are secreted in the lungs of CF patients, where they are a potentially deleterious reservoir of active proteases, and that they do not display any bactericidal effect towards S. aureus and P. aeruginosa. Our work shows that the signalization pathways leading to NETs secretion vary depending on the stimulus, generating structures that present different properties.

A existência de uma família gênica diversa de serino proteinases em Lepidóptera sugere que essas proteinases desempenham um papel importante na adaptação desses insetos à presença de inibidores de proteinases vegetais. Essas enzimas têm se revelado estarem envolvidas no processo digestivo de larvas de insetos. Larvas de Spodoptera frugiperda foram alimentadas com uma dieta suplementada com inibidor de proteinase de soja (IPS) e a expressão gênica de proteinases intestinais foi avaliada através de PCR em tempo real. Análises de transcrição anteriores mostraram a existência de dois grupos de serino proteinases: um grupo de genes constitutivamente expressos em larvas controle que é induzido pela dieta contendo IPS e um segundo grupo que está ausente no controle, mas que é também induzido por uma dieta rica em IPS. No presente trabalho foi observado um terceiro grupo de proteinases que não são nem induzidas nem reprimidas pela presença do IPS na dieta. Essa observação sugere que a adaptação de S. frugiperda ao IPS envolve a síntese de novas proteinases, a indução de enzimas preexistentes e ainda um terceiro grupo insensível à presença dos inibidores. Proteinases dos intestinos de larvas crescidas em dieta com IPS mostraram insensibilidade ao inibidor. As proteinases também foram insensíveis quando a atividade foi verificada com um inibidor de proteinases de amplo espectrum. Os resultados aqui apresentados propõem que a adaptação de S. frugiperda ao IPS segue uma estratégia generalizada, baseada na indução geral de um grande grupo de endoproteinases. / The existence of a diverse serine proteinase gene family in lepidopteran insects has suggested its significant role in the insect adaptation to plant proteinase inhibitors. These enzymes have been shown to be involved in the proteolytic digestion process of insect larvae. Spodoptera frugiperda larvae were fed on a diet supplemented with soybean proteinase inhibitor (SPI) and the gene expression of intestinal proteinases was evaluated by real time PCR. Previous transcription analyses found two groups of intestinal serine proteinases: one group of genes constitutively expressed in the control larvae that is induced by the SPI-containing diet during the experiment, and a second group that is absent in the control but also induced by the SPI rich diet. Herein was observed a third group of proteinases that are neither induced nor repressed by the presence of SPI in the diet. This observation suggests that adaptation of S. frugiperda to SPI involves de novo synthesis, up regulation of existing enzymes and that there is a third group insensitive to the presence of the inhibitors. Proteinases from intestines of larvae reared on a diet with SPI showed insensitivity to the inhibitor. The proteinases were also insensitive when the activity was checked with a broad-spectrum potato proteinase inhibitor. The results here presented propose that adaptation of S. frugiperda to SPI follows a \"shotgun\" approach, based on a general up regulation of a large set of endoproteinases.

Neste estudo foram avaliados os efeitos das serinoproteinases PA-BJ e giroxina, isoladas dos venenos das serpentes Bothrops jararaca e Crotalus durissus terríficus, respectivamente, sobre células endoteliais (CEs) em cultura. Os resultados obtidos demonstraram que essas toxinas, nas concentrações utilizadas, não afetaram a viabilidade e a integridade das CEs. Por outro lado, induziram a liberação de PGI2, que foi significativamente reduzida por inibidores não seletivos e seletivos das ciclooxigenases -1 e -2 (COX-1 e -2), mas não afetaram a expressão protéica constitutiva das mesmas. Adicionalmente, foi demonstrado que o antagonista de receptores PAR-1, o SCH 79797, não alterou a liberação de PGI2, induzida pelas toxinas. Em conclusão, essas toxinas, em concentrações não citotóxicas, induziram a liberação de PGI2 a partir de CEs, de modo dependente da ativação das COX-1 e -2. Por outro lado, o receptor PAR-1 não parece ser importante para este efeito, nessas células. / In this study, the effects of PA-BJ and gyroxin, isolated from Bothrops jararaca and Crotalus durissus terrificus snake venoms, respectively, on endothelial cells in culture were investigated. Results showed that neither PA-BJ nor gyroxin affected the integrity of monolayers nor modified ECs viability in the periods of incubation tested. In contrast, these serine proteinases increased the release of prostacyclin from ECs. This effect was inhibited by both non-selective and selective COX-1 and COX-2 inhibitors, but these toxins did not affect the protein expression of COX-1 and -2. Inhibition of the catalytic activity of PA-BJ and gyroxin or pre-incubation of ECs with PAR-1 antagonist did not abrogate the ability of these toxins to induce PGI2 release. These findings demonstrate that these serine proteinases are able to stimulate production of prostacyclin by ECs by a mechanism dependent on stimulation of COX-1 and COX-2 enzyme activity. Moreover, neither enzyme activity of both serine proteinases nor the receptor PAR-1 contribute for this effect on endothelium.

Made available in DSpace on 2015-07-22T20:49:22Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-07-28 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Aranhas do gênero Loxosceles, são responsáveis por acidentes em todo o mundo, com grande importância clínica no Sul do Brasil. Os venenos destas aranhas são compostos por diversas toxinas, entre elas proteínas, responsáveis pelo quadro conhecido como loxoscelismo. No intuito de descrever o perfil transcricional da glândula produtora de veneno da aranha Loxosceles intermedia geramos uma biblioteca de cDNA bastante ampla e seus transcritos foram funcionalmente caracterizados. Após o processamento inicial das sequências, 1.843 ESTs (Expressed Sequence Tags) apresentavam qualidade suficiente para as análises posteriores. Estas sequências foram montadas em 538 clusters, sendo que 281 eram singletons. Após análises de similaridade, mais de 50% das ESTs demonstraram algum grau de semelhança com proteínas conhecidas. As análises de similaridade também demonstraram que os transcritos que codificavam para toxinas, perfaziam 43% de todas as sequências e abrangem uma parte significativa das ESTs. As toxinas mais frequentes foram anotadas como pertencentes à família LiTx de toxinas inseticidas. As fosfolipases-D e as metaloproteases semelhantes à astacinas perfazem, cada uma, cerca de 9% do total de transcritos. Componentes tóxicos tais como inibidores de serino-proteases, hialuronidase e proteínas alergênicas foram também identificadas, porém com menor representação. Quase 10% das ESTs codificam para proteínas envolvidas em processos celulares. O presente trabalho descreve também as etapas para clonagem, expressão heteróloga e purificação de um transcrito semelhante a um inibidor de serino-protease, identificado na biblioteca de cDNA. É sabido que proteínas desta família apresentam um grande potencial de aplicação como drogas antitrombóticas, atuando como agentes terapêuticos que influenciam a atividade de fatores de coagulação. Esses dados fornecem uma visão global do perfil de expressão da glândula de veneno de L. intermedia, revelam diferenças significantes entre venenos de aranhas do gênero Loxosceles e descrevem a produção de uma nova toxina recombinante. / Loxosceles genus spiders are responsible for accidents all over the world and have clinical importance in the South of Brazil. The venom of these spiders is made up of several toxins, including proteins, which are responsible for the clinical pattern called loxoscelism. To describe the transcriptional profile of the L. intermedia venom gland, we generated a wide cDNA library, and its transcripts were functionally and structurally analyzed. After initial analyses, 1,843 ESTs produced readable sequences that were grouped into 538 clusters, 281 of which were singletons. Nine hundred eighty-five reads (53% of total ESTs) matched to known proteins. Similarity searches showed that toxinencoding transcripts totalize 43% of the total library and comprise a great number of ESTs. The most frequent toxins were from the LiTx family, which are known for their insecticidal activity. Both phospholipase-D and astacin-like metalloproteases toxins account for approximately 9% of total transcripts. Toxins components such as serine proteases, hyaluronidases and venom allergens were also found but with minor representation. Almost 10% of the ESTs encode for proteins involved in cellular processes. This work also describes the stages for cloning, heterologous expression and purification of a cDNA similar to a protease inhibitor identified in the cDNA library. It is known that proteins belonging to this family have an application potential as antithrombotic drugs, acting as therapeutic agents that influences the activity of coagulation factors. These data provide an important overview of the L. intermedia venom gland expression scenario, revealed significant differences from profiles of other spiders from the Loxosceles genus and describe the production of a novel recombinant toxin. / TEDE / BV UNIFESP: Teses e dissertações