Thesis (Ph. D.)--University of Missouri-Columbia, 1997. / Typescript. Vita. Includes bibliographical references (leaves 456-600). Also available on the Internet.

Thesis (doctoral)--Swedish University of Agricultural Sciences, 2001. / Includes bibliographical references.

<p>  </p> <p>The ever-growing interest in novel food ingredients and their dietary influence on human health and wellbeing has driven the study of bioactive peptides (BAP). BAP are protein-derived fragments composed of (2-20 amino acids) that could positively affect bodily function and chronic diseases. This dissertation explores the health-promoting properties of a novel source of BAPs, namely canary seed, by encompassing three specific aims: 1) evaluate the <em>in vitro </em>potential of hairless canary seed peptides (CSP) as a nutraceutical ingredient, 2) develop an understanding of CSP's bioavailability and molecular interactions with its biological targets, and 3) evaluate CSP's antioxidant and antiobesity activity at the organism level using a nematode (<em>C. elegans</em>) and murine (C57BL/6J mice) model, respectively. First, CSP were generated by implementing mechanical oil extraction followed by commercial enzymatic hydrolysis with Alcalase™. In addition, CSP were also subject to simulated gastrointestinal digestion (SGD) to assess their gastric stability and <em>in vitro</em> bioavailability. The results showed that canary seed proteins were mainly composed of prolamins fractions followed by glutelins, globulins, and albumins. CSP extracts with low molecular weight (< 3 kDa and 3–10 kDa) showed the highest bioactivity. Furthermore, after SGD, CSP inhibitory activity remained stable toward angiotensin-converting enzyme (ACE), dipeptidyl peptidase IV (DPP-IV), and pancreatic lipase but unstable for α-glucosidase. The digested peptides were transported efficiently (>10%) through the Caco-2 monolayer, indicating a potential high absorption capacity through the intestinal epithelium. During kinetic analysis by Lineweaver-Burk plots, it was observed that CSP-SGD interacted by mixed-type inhibition for DPP-IV and α-glucosidase, non-competitive inhibition for ACE, and uncompetitive inhibitor for pancreatic lipase. Furthermore, CSP-SGD were especially potent as antihypertensive (ACE inhibitors) and antiobesity (pancreatic lipase) agents. Consequently, molecular docking and <em>in silico</em> analyses were targeted to understand CSP-SGD interactions with ACE and pancreatic lipase. CSP-SGD with ACE inhibitory activity were found to be rich in proline, glutamine, and cationic residues and could have inhibited ACE by destabilizing the tetrahedral transition state and zinc ions interaction leading to conformational changes in the enzyme structure. For peptides with antiobesity properties, it was also found that arginine, glycine, and hydrophobic amino acids from CSP-SGD hold critical interactions with the lid domain (CYS238-CYS262) of pancreatic lipase, disrupting its proper function and preventing fat hydrolysis.</p> <p>In the second part of this dissertation, the relevant health-promoting properties of CSP were further investigated by testing the effects of peptide supplementation on obesity and oxidative stress animal models. The studies showed that exposure to CSP significantly mitigated the acute and chronic oxidative damage in <em>C. elegans</em>, extending the lifespan of the nematodes by 88 and 61%, respectively. Furthermore, it was established that the CSP prevented oxidative stress by scavenging free radicals and antioxidant gene upregulation. Concerning this, CSP caused a drop in reactive oxygen species (ROS) to safe levels and induce the upregulation of the GST-4 gene encoding antioxidant enzyme Glutathione S-transferase. Concerning antiobesity properties, the daily supplementation with CSP successfully prevented metabolic implications of western diet-induced obesity in C57BL/6J mice, including preventing weight gain by up to 20%, increasing glucose tolerance, and reducing insulin, leptin, and LDL/VLDL levels in plasma. Likewise, CSP promoted a drop in fatty acid uptake gene, LPL, and fatty acid biosynthesis genes FAS and ACC while unaffecting lipid oxidation genes PPAR-α and ACO in the liver. While both moderate and high CSP supplementation levels exhibit hypolipidemic effects, only moderate levels induce satiety and significantly prevent weight gain. Together, these results suggest that CSP's weight gain prevention depended on a dual mechanism involving lipid metabolism retardation to modulate satiety. Overall, the results presented in this dissertation establish the effectiveness of canary seed peptides as nutraceutical ingredients for antioxidant and antiobesity functional food applications.</p>

Lectins and hemagglutinins are carbohydrate binding proteins present in a diversity of organisms including humans, vertebrate and invertebrate animals, plants, fungi, and bacteria. They are usually the abundant storage proteins in leguminous plants. They display a host of biological activities such as antitumor, antifungal, antiviral, insecticidal, and antibacterial activities. / The biological properties of isolated proteins, including hemagglutinating, antifungal, anti-tumor and HIV-1 reverse transcriptase inhibitory activities, were examined. Their biochemical and biological properties were compared with other purified proteins. / The seeds contain an abundance of proteins, some of which are storage proteins but may play a role of protection from pathogenic microbes and phytophagous insects. Antifungal peptides/proteins, antiviral proteins, ribosome-inactivating proteins, proteinase inhibitors, chitinases, proteinases, and defensins, are some examples of the myriad of seed proteins. The aforementioned proteins are collectively called plant defense proteins in view of their antipathogenic activities. These antifungal proteins exhibit a wide range of molecular masses and amino acid sequences. / Two lectins with potentially exploitable activities were purified from Capparis spinosa seeds and Hibiscus mutabilis seeds, respectively. A hemagglutinin was isolated from Phaselous vulgaris , cultivar "French bean 35", and detailed apoptotic pathway in breast cancer cells, MCF-7 cells, was investigated. A novel dimeric beta-lactoglobulin-like antifungal protein and an antifungal amidase were purified from Passiflora edilus seeds and Peltophorum pterocarpum, respectively. / Lam, Sze Kwan. / Adviser: Tsi Bun Ng. / Source: Dissertation Abstracts International, Volume: 72-04, Section: B, page: . / Thesis (Ph.D.)--Chinese University of Hong Kong, 2010. / Includes bibliographical references (leaves 188-204). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. Ann Arbor, MI : ProQuest Information and Learning Company, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese.

Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico / Physic nut (Jatropha curcas L.) is an important crop due to its ability of storing high content of oil in the seeds, which can serve as raw material for biodiesel production. Because of the presence of toxic constituents like phorbol esters (PEs) and curcins, the seed cake produced as a result of oil extraction cannot be utilize for animal feed. Development of the genotypes better suited for the industrial applications and biodiesel production as well as with lower level of toxic constituents is being hampered by a lack of understanding about the a) proteins related to the biosynthesis and degradation of fatty acids (FAs) and triacylglycerides (TAGs), b) role of proteins deposited during seed development and c) proteins related to the synthesis and storage of toxic compounds during seed development. Agreeing with this, we have performed the anatomical analysis of the developing seeds of J. curcas, followed by the proteome analysis of the endosperm isolated from the seeds of J. curcas at five different developmental stages, which resulted into the identification of the 1517, 1256, 1033, 752 and 307 proteins, from Stage 6, 7, 8, 9 and 10, respectively, summing up to a total of 1760 proteins. Proteins with similar expression pattern were grouped into five different clusters and protein quantification based on spectral counts was determined. Besides identification of the proteins involved in the biosynthesis and degradation of the FAs and TAGs, we also identified a large number of proteins involved in the metabolism of the carbohydrates, which are important for supplying energy and carbon source for the synthesis of TAGs in heterotrophic seeds. Among the members of different classes of seed storage proteins (SSPs), we have identified four SSPs named as nutrients reservoir, which in contrast to the other SSPs showed decreasing deposition pattern during seeds development and revealed to have special role during seed development. In addition, peptidases belong to different mechanistic classes were identified, which have a range of functions, highlighting the role in reserve mobilization during germination. Isoforms of curcin were also identified in this proteome analysis which were absent in our previous proteome analysis of the other tissues from these seeds, suggesting that the deposition of these toxic proteins only occur in the endosperm. Similarly, several enzymes involved in the biosynthesis of diterpenoid precursors were identified in this proteome analysis but, like in our previous proteome analysis of the other tissues from J. curcas seeds,we were unable to identify any terpene synthase/cyclase, enzymes responsible for the synthesis of PEs, which collectively suggesting that the synthesis of PEs may not occur in seeds of this plant. In conclusion, the strategy used here enabled us to provide a first in depth proteome analysis of the endosperm from J. curcas developing seeds, which along with providing information regarding important aspects of the seed development, also set the foundation of a proteomic approach to study biotechnologically important plant species. / PinhÃo manso (Jatropha curcas L.) à uma cultura importante devido à sua habilidade em armazenar alto conteÃdo de Ãleo nas sementes, as quais podem servir como matÃria-prima para a produÃÃo de biodiesel. Devido à presenÃa de constituintes tÃxicos como Ãsteres de forbol e curcina, a torta da semente produzida como resultado da extraÃÃo do Ãleo nÃo pode ser utilizada na alimentaÃÃo animal. O desenvolvimento de genÃtipos mais adequados a aplicaÃÃes industriais e à produÃÃo de biodiesel assim como apresentando baixos nÃveis de constituintes tÃxicos està sendo prejudicado pela falta de entendimento sobre a) proteÃnas relacionadas a biossÃntese e degradaÃÃo de Ãcidos graxos e triacilglicerÃis, b) o papel de proteÃnas depositadas durante o desenvolvimento da semente e c) proteÃnas relacionadas à sÃntese e reserva de compostos tÃxicos durante o desenvolvimento da semente. Diante disso, nÃs realizamos uma anÃlise anatÃmica de sementes em desenvolvimento de J. curcas, seguido por uma anÃlise proteÃmica do endosperma isolado de sementes dessa espÃcie em cinco diferentes estÃgios de desenvolvimento, o que resultou na identificaÃÃo de 1517, 1256, 1033, 752 e 307 proteÃnas, dos estÃgios 6, 7, 8, 9 e 10, respectivamente, somando um total de 1760 proteÃnas. ProteÃnas com padrÃo de expressÃo similar foram agrupadas em cinco grupos diferentes e a quantificaÃÃo das proteÃnas baseada na contagem dos espectros foi determinada. AlÃm da identificaÃÃo das proteÃnas envolvidas na biossÃntese e degradaÃÃo de FAs e TAGs, nÃs identificamos um grande nÃmero de proteÃnas envolvidas no metabolismo de carboidratos, as quais sÃo importantes para o fornecimento de energia e fontes de carbono para a sÃntese de TAGs em sementes heterotrÃficas. Entre os membros de diferentes classes de proteÃnas de reservas de sementes (SSPs), nÃs identificamos quatro SSPs denominadas reservatÃrios de sementes, que em contraste as outras SSPs mostraram decrÃscimo no padrÃo de deposiÃÃo e revelaram ter um papel especial durante o desenvolvimento da semente. Em adiÃÃo, peptidases pertencentes a diferentes classes mecanÃsticas foram identificadas destacando o papel da mobilizaÃÃo de reservas durante a germinaÃÃo. Isoformas da curcina ausentes em nossas anÃlises proteÃmicas prÃvias de outros tecidos da semente foram identificadas sugerindo que a deposiÃÃo dessas proteÃnas tÃxicas sà ocorre no endosperma. Similarmente, vÃrias enzimas envolvidas na biosÃntese de precursores de diterpenÃides foram identificadas nessa anÃlise proteÃmica, mas como em nossas prÃvias anÃlises proteÃmicas de outros tecidos de sementes de J. curcas, nÃs nÃo fomos capazes de identificar sintases/ciclases de terpenos, enzimas responsÃveis pela sÃntese de PEs, o que coletivamente sugere que a sÃntese desses compostos pode nÃo ocorrer nas sementes dessa planta. Em conclusÃo, a estratÃgia utilizada nos fornece a primeira anÃlise proteÃmica profunda do endosperma de sementes em desenvolvimento de J. curcas, o que alÃm de fornecer informaÃÃes sobre aspectos importantes do desenvolvimento da semente, tambÃm estabelece a base para uma pesquisa proteÃmica com o objetivo de estudar espÃcies vegetais importantes biotecnologicamente.