A Araucaria angustifólia é uma conífera nativa do Brasil que apresenta sementes recalcitrantes. Devido a sua importância econômica, foi intensamente explorada ao longo dos anos, encontrando-se atualmente classificada como espécie em perigo crítico de extinção pela International Union for Conservation of Nature. A embriogênese somática apresenta-se como uma ferramenta biotecnológica de grande valia na propagação de espécies recalcitrantes e de difícil propagação, com aplicação em programas de conservação, reflorestamento, e melhoramento genético vegetal. Estudos comparativos dos processos de embriogênese somática e zigótica têm permitido o conhecimento dos fatores bioquímicos, fisiológicos e genéticos que controlam o desenvolvimento do embrião, e o estabelecimento as condições artificiais para o correto desenvolvimento embrionário in vitro. O objetivo deste trabalho foi estudar a participação do ácido salicílico como sinalizador do processo de embriogênese zigótica e somática em A. angustifólia. Para tanto foi determinado o conteúdo de ácido salicílico livre e conjugado ao longo da embriogênese zigótica, e o efeito de sua suplementação em culturas embriogênicas com diferentes potenciais para a maturação. Para a embriogênese somática, a presença do ácido salicílico foi correlacionada com a geração de óxido nítrico e espécies reativas de oxigênio , e com a expressão do gene \"Somatic Embryogenesis Receptor Kinase\" (AaSERK). Os resultados obtidos demonstram que: a) ocorre um maior conteúdo de ácido salicílico na forma livre e conjugada nas etapas iniciais da embriogênese zigótica; b) a suplementação de ácido salicílico, nas concentrações de 0,5 a 2 mM, inibiram a indução de culturas embriogênicas; c) culturas embriogênicas incubadas em ácido salicílico apresentaram redução da síntese endógena de espécies reativas de oxigênio e aumento no conteúdo de óxido nítrico; d) a redução de espécies reativas de oxigênio indicou uma relação dose dependente com o ácido salicílico; e) a adição de um doador de óxido nítrico e um sequestrador inibiram a produção de espécies reativas de oxigênio; f) a expressão do gene AaSERK atingiu o maior nível no período de quatro horas de incubação em 0,1 mM de AS / Araucaria angustifolia is a conifer native of Brazil with recalcitrant seeds. Due to its economic importance, the exploration has been extensively over the years, currently this specie is classified as critically endangered by the International Union for Conservation of Nature. Somatic embryogenesis is presented as a biotechnological tool of great value in the propagation of recalcitrant species and difficult to spread, with applications in conservation, reforestation programs, and plant breeding. Comparative studies of the processes of zygotic and somatic embryogenesis has allowed the knowledge of biochemical, physiological and genetic factors that control embryo development, and the establishment artificial conditions for proper embryonic development in vitro. The objective of this work was to study the role of salicylic acid as a marker of zygotic embryogenesis and somatic process in A. angustifolia. Thus, we determined the content of free salicylic acid and conjugated along the zygotic embryogenesis, and the effect of their supplementation with different potential embryogenic cultures for maturation. For somatic embryogenesis, the presence of salicylic acid was correlated with the generation of nitric oxide, reactive oxygen species and in the gene expression \"Somatic embryogenesis Receptor Kinase\" (AaSERK). The results show that: a) there is an increased content of salicylic acid in free and conjugated form in the initial stages of zygotic embryogenesis; b) salicylic acid supplementation, in concentrations from 0.5 to 2 mM, inhibited the induction of embryogenic cultures; c) embryos incubated in salicylic acid decreased endogenous synthesis of reactive oxygen species and increase in content of nitric oxide; d) the reduction of reactive oxygen species indicated a dose-dependent relationship with salicylic acid; e) the addition of a nitric oxide donor and a kidnapper inhibited the production of reactive oxygen species; f) the expression of the gene AaSERK reached the highest level in four hours of incubation in 0.1 mM AS

A interacao planta-patogeno desencadeia uma serie de sinais que ainda nao estao completamente elucidados. Uma das respostas e a reacao de hipersensibilidade (RH), onde ocorre a morte celular programada no sitio da infeccao, impedindo a proliferacao do patogeno. Acredita que a morte celular e provocada pelo aumento do ERO, principalmente peroxido de hidrogenio (H2O2) e com o acumulo de acido salicilico (AS) que inibe a catalase, enzima responsavel pela transformacao de H2O2 em H2O e O2. Alem disso, ocorre o aumento da sintese e liberacao dos compostos fenolicos e alteracao da parede celular dos vegetais, com o aumento das atividades de diversas enzimas, capazes de degradar a parede celular da planta e do microrganismo invasor, liberando fragmentos que podem atuar como moleculas sinalizadoras, tornando as plantas mais resistentes. Nesse trabalho as celulas de Rubus fruticosus (amora-preta) foram tratadas, separadamente, com tres diferentes moleculas elicitoras, ou seja, moleculas capazes de ativar o mecanismo de defesa das plantas, o acido salicilico (AS), o metil jasmonato (MeJA) e ramnoglucuronogalactana (F-I), na concentracao de 1 Êmol/L durante 1h, para o estudo dos componentes extracelulares liberados e das modificacoes dos monossacarideos da parede celular durante resposta de hipersensibilidade. A concentracao de proteinas totais extracelulares foi aumentada com os indutores F-I e MeJA. A atividade enzimatica de -D-xilosidase nao se alterou na presenca de F-I, AS e MeJA. Entretanto, o MeJA tem a capacidade de aumentar as atividades das enzimas -D-galactosidase, -Dglucosidase, quitinase e laminarinase e inibir as atividades das enzimas galacturonase e -Lfucosidase na concentracao e tempo usado. O AS e F-I provocaram um aumento nas atividades de galacturonase e quitinase e inibiram a laminarinase. A aplicacao exogena de F-I e AS induziram a liberacao de compostos fenolicos para meio extracelular, que provavelmente, foi decorrente da tentativa das celulas de se protegerem de microrganismos invasores, com um decrescimo desses compostos no meio intracelular. O MeJA nao foi capaz de alterar a sintese de compostos fenolicos totais intracelulares e extracelulares e de acucares extracelulares, em tais condicoes. Tambem F-I e AS nao alteraram o teor de acucar redutor extracelular. O MeJA foi mais efetivo na producao de ERO durante 30 minutos de incubacao na concentracao de1 Êmol/L . F-I foi tambem ativador na liberacao de ERO, no entanto, o AS provocou inibicao. Os principais monossacarideos neutros que constitui a parede celular de suspensao de celulas de Rubus fruticosus sao as glucose (55-61%), arabinose (22-29%) e manose (13,8-15%). Ocorrendo em menor concentracoes os monossacarideos de fucose (0,65-1,2%), galactose (0,5-0,8%), xilose (0,5-0,8%) e ramnose (aproximadamente 0,5%).Os monossacarideos ramnose, fucose, xilose e galactose de parede celular tiveram um decrescimo na presenca do AS e um aumento na presenca de MeJA. Entretanto, o AS e o MeJA nao alteraram o percentual de arabinose, manose e glucose. O F-I foi capaz de aumentar o percentual dos monossacarideos ramnose e fucose e diminuir de glucose. Os resultados obtidos demonstram que a via de ativacao dos mecanismos de defesa da celula vegetal, induzida pelo MeJA, difere das vias ativadas pelo AS e F-I, pois o F-I e o AS induziram a liberacao de compostos fenolicos e o MeJA provocou aumento nas atividades enzimaticas, principalmente que atuam na parede celular da propria planta. O AS e o F-I foram mais efetivos no aumento das atividades enzimaticsa relacionadas a defesa da planta, as quais agem nas paredes de diversos fitopatogenos, sendo que as enzimas que podem atuar na parede celular da propria planta foram inibidas ou nao sofreram alteracao. / The plant-pathogen interactions trigger a series of signals that are not yet completely understood. One of the mechanisms is the hypersensitive response (HR), which is characterized by cell death in the infection site in order to prevent pathogen proliferation. Our previous studies with different elicitors demonstrated the correlation between the formation of reactive oxygen species (ROS) and cell wall degradation. Here, the cells were elicited with 1 mol/L salicylic acid (SA), methyl jasmonate (MeJA) or acid polysaccharide (rhamnoglucuronogalactan, F-I) (1mol/L) from characterization the extracellular components released and the modifications of the monosaccharide composition in cell wall during a hypersensitive response in Rubus fruticosus (blackberry-black).The extracellular proteins released to the extracellular were increased with the inducers molecules F-I and MeJA. The -D-xylosidase enzymatic activities didnt change in the presence of F-I, SA and MeJA. The time-course curves for -D-galactosidase, -D-glucosidase activities in fraction E were most effective for MeJA, while F-I and AS inhibited -Dgalactosidase. Also, the MeJA has ability to activate laminarinase and chitinase enzymatic activities and inhibit galacturonase and -L-fucosidase enzymatic activities. After 1h, the SA and F-I caused an increase galacturonase and chitinase activities and inhibited laminarinase enzymatic activity. Also, the time-course curves chitinase in the fraction increased with SA.The F-I and SA increased extracellular phenolic compounds, although they decreased them in the fraction I. MeJA was unable to change the synthesis of either intracellular or extracellular phenolic compounds. The data suggest that F-I and AS modulate the defense responses of plants through a via different that of MeJA. The extracellular reducing sugar didnt change with F-I, SA and MeJA.The MeJA was more effective in the release ROS incubation of 30 minutes at concentration of 1 mol/L. However, the presence of SA caused inhibition and F-I activated of ROS by cells.The main constituents of neutral sugars in the cell wall of Rubus fruticosus were glucose (55-61%), arabinose (22-29%) and mannose (13.8-15%). Minor constituents were fucose (0.65-1.2%), galactose (0.5- 0.8%), xylose (0.5-0.8%) and rhamnose (~0.5%). SA decreased the rhamnose and fucose concentrations; F-I both decreased the percentage of mannose and glucose and increased rhamnose and fucose. MeJA, in turn, increased the percentage of rhamnose, xylose and galactose. The data suggest that F-I and SA modulate the defense responses of plants through a mechanism unrelated to the MeJA via. Since the F-I and the SA induced the release phenolic compounds and the MeJA increased in enzymatic activities, mainly age in the own plant cell wall. The SA and F-I were more effective in the increasing defense enzyme-related activity of the plant that acts on the walls of several phytopathogens, and the enzymes that can act in the cell wall of the plant were inhibited or did not change.

The purpose of this research was to investigate the effects that aspirin (ASA) and its metabolites, salicylic acid (SA) and acetic acid (AA), have on the delivery of drugs across biological barriers when used in conjunction with electroporation. Electroporation is a technique used to enhance drug delivery across bio-membranes in which a transmembrane potential is induced into cellular membranes, resulting in the creation of aqueous pores that allow molecules to pass through the otherwise impermeable barrier. Aspirin is a widely used drug that has been used for over a century and has been proven relatively safe at normal doses as indicated by the low number of reports of poisoning cases it has been involved in. Components of aspirin are known to soften the cellular membranes by solubilizing the cell's surface proteins. B16F10 murine melanoma cancer cells were used in this investigation and treated with a 120µM buffered solution of calcein, a fluorescent indicator, in which the amount of delivered tracer molecules was measured using fluorescence. Identical concentrations of ASA and SA were investigated (1mM, 5mM, and 10mM) separately, focusing the effects concentration has electroporation delivery. Diluted acetic acid was also investigated at pH values of 6.42, 5.36, and 4.40. The concentration of acetic acid that had the lowest pH and ASA with the highest concentration had the greatest impacts on the augmentation of calcein delivery. Therefore, this demonstrates that aspirin and acetic acid have the potential to improve targeted molecular delivery in combination with electroporation.

Emulsions are widely used as topical formulations in the pharmaceutical and cosmetic industry. They are thermodynamically unstable and require emulsifiers to stabilize them physically. A literature survey has revealed that emulsifiers could have an effect on topical delivery. Therefore, the overall aim of this research project was to investigate and to understand the various effects of biopolymers, chosen for this study as emulsifiers, on the release and the topical delivery of an active ingredient from emulsion-based delivery systems. Emulsions were stabilized by either whey protein alone or in combination with chitosan or carrageenan. Salicylic acid was chosen as a model drug. Furthermore, the emulsions were prepared at three different pH values (pH 4, 5 and 6) in order to introduce different charges to the polymeric emulsifiers and subsequently determine the effect of pH on release as well as on dermal and transdermal delivery. Emulsion characteristics, such as droplet size, zeta potential, viscosity and stability against creaming and coalescence were ascertained. In addition, turbidity was determined to evaluate the degree of insoluble complex formation in the aqueous phase of the emulsions. A high pressure liquid chromatographic (HPLC) method was validated for the quantitative determination of salicylic acid in the release, skin and transdermal perfusate samples. Nine emulsions were formulated, utilizing the layer-by-layer (LbL) self-assembly technique, from which the release of salicylic acid was determined. These release studies were conducted, utilizing nitrocellulose membranes (0.2 μm pore size) with the use of Franz-type diffusion cells in four replicates per formulation over a time period of 8 hours. Based on the emulsion characterization and release data, six formulations, including the oil solution, were chosen to determine dermal and transdermal delivery of salicylic acid. During the diffusion studies, the effect of different pH (whey protein pH 4.00, 5.00 and 6.00), different polymers and different polymer combinations were investigated. These diffusion studies were conducted with the use of dermatomed (thickness ~400 μm), human abdominal skin and Franz-type diffusion cells over a period of 24 hours. The characterization of the emulsions revealed no significant differences in the droplet size and viscosity between the various formulations. All emulsions showed stability towards coalescence over a time period of 7 days; however, not all the emulsions showed stability towards creaming and flocculation. The results of the release studies indicated that an increase in emulsion droplet charge could have a negative effect on the release of salicylic acid from these formulations. In contrast, positively charged emulsion droplets could enhance the dermal and transdermal delivery of salicylic acid from emulsions. It was hypothesized that electrostatic complex formation between the emulsifier and salicylic acid could affect the release, whereas electrostatic interaction between emulsion droplets and skin could influence dermal/transdermal delivery of the active. Furthermore, the degree of ionization of salicylic acid played an important role in the dermal and transdermal delivery of salicylic acid from the various emulsions. / MSc (Pharmaceutics), North-West University, Potchefstroom Campus, 2014

Emulsions are widely used as topical formulations in the pharmaceutical and cosmetic industry. They are thermodynamically unstable and require emulsifiers to stabilize them physically. A literature survey has revealed that emulsifiers could have an effect on topical delivery. Therefore, the overall aim of this research project was to investigate and to understand the various effects of biopolymers, chosen for this study as emulsifiers, on the release and the topical delivery of an active ingredient from emulsion-based delivery systems. Emulsions were stabilized by either whey protein alone or in combination with chitosan or carrageenan. Salicylic acid was chosen as a model drug. Furthermore, the emulsions were prepared at three different pH values (pH 4, 5 and 6) in order to introduce different charges to the polymeric emulsifiers and subsequently determine the effect of pH on release as well as on dermal and transdermal delivery. Emulsion characteristics, such as droplet size, zeta potential, viscosity and stability against creaming and coalescence were ascertained. In addition, turbidity was determined to evaluate the degree of insoluble complex formation in the aqueous phase of the emulsions. A high pressure liquid chromatographic (HPLC) method was validated for the quantitative determination of salicylic acid in the release, skin and transdermal perfusate samples. Nine emulsions were formulated, utilizing the layer-by-layer (LbL) self-assembly technique, from which the release of salicylic acid was determined. These release studies were conducted, utilizing nitrocellulose membranes (0.2 μm pore size) with the use of Franz-type diffusion cells in four replicates per formulation over a time period of 8 hours. Based on the emulsion characterization and release data, six formulations, including the oil solution, were chosen to determine dermal and transdermal delivery of salicylic acid. During the diffusion studies, the effect of different pH (whey protein pH 4.00, 5.00 and 6.00), different polymers and different polymer combinations were investigated. These diffusion studies were conducted with the use of dermatomed (thickness ~400 μm), human abdominal skin and Franz-type diffusion cells over a period of 24 hours. The characterization of the emulsions revealed no significant differences in the droplet size and viscosity between the various formulations. All emulsions showed stability towards coalescence over a time period of 7 days; however, not all the emulsions showed stability towards creaming and flocculation. The results of the release studies indicated that an increase in emulsion droplet charge could have a negative effect on the release of salicylic acid from these formulations. In contrast, positively charged emulsion droplets could enhance the dermal and transdermal delivery of salicylic acid from emulsions. It was hypothesized that electrostatic complex formation between the emulsifier and salicylic acid could affect the release, whereas electrostatic interaction between emulsion droplets and skin could influence dermal/transdermal delivery of the active. Furthermore, the degree of ionization of salicylic acid played an important role in the dermal and transdermal delivery of salicylic acid from the various emulsions. / MSc (Pharmaceutics), North-West University, Potchefstroom Campus, 2014

The aim of this study was to gain insight into the nature of resistance genes and mechanisms of resistance present in different ascochyta blight (AB) resistant genotypes of lentil to efficiently select non-allelic AB resistance genes mediating different mechanisms of resistance for gene pyramiding. Recombinant inbred lines (RILs) from all possible crosses among AB resistant Lens culinaris genotypes CDC Robin, 964a-46, ILL 7537 and ILL 1704 were subjected to allelism tests. Efforts were also made to understand the genetics of resistance in the L. ervoides accession L-01-827A. LR-18, a RIL population from the cross CDC Robin × 964a-46 was subjected to quantitative trait loci (QTL) mapping using a comprehensive genetic linkage map previously developed from polymorphic SNPs, SSRs and phenotypic markers. Results of allelism tests suggested that genes conditioning resistance to ascochyta blight in all lentil genotypes were non-allelic. Two complementary recessive resistance genes in L-01-827A were detected. QTL analysis indicated that CDC Robin and 964a-46 were different at two AB resistance QTLs. Histological tests suggested that cell death inhibition in CDC Robin, and reduced colonization of epidermal cells in 964a-46 might be the mechanisms of resistance in these genotypes. Comparing the expression of key genes in the salicylic acid (SA) and jasmonic acid (JA) signaling pathways of CDC Robin and 964a-46 suggested that the SA pathway was strongly triggered in 964a-46. However, the JA pathway was triggered in both, but at a lower expression level in 964a-46 than in CDC Robin. RNA-seq analysis revealed a number of candidate defense genes differentially expressed among genotypes with hypothetical actions in different layers of the plant defense machinery. The expression levels of the six candidate defense genes measured by quantitative real-time PCR analysis was correlated with those of RNA-seq. In conclusion, 964a-46 and CDC Robin mediated resistance to ascochyta blight through different resistant mechanisms, making them ideal candidates for resistance gene pyramiding. Gene pyramiding can be accelerated using closely linked markers to CDC Robin and 964a-46 resistance genes identified through QTL analysis.

Soybean [Glycine max (L.) Merr.] is an important crop worldwide. It has been widely consumed for protein, oil and other soy products. To develop soybean cultivars with greater resistance against pests and improved meal quality, it is important to elucidate the molecular bases of these traits. This dissertation aims to investigate the biochemical and biological functions of soybean genes from four gene families, which are hypothesized to be associated with soybean defense against pests and soybean meal quality. There are three specific objectives in this dissertation. The first one is to determine the function of components in the salicylic acid (SA) signaling pathway in soybean resistance against soybean cyst nematode (Heterodera glycines, SCN). The second one is to determine whether insect herbivory induce the emission of volatiles from soybean, and if so, how these volatiles are biosynthesized. The third objective is to identify and characterize soybean mannanase genes that can be used for the improvement of soybean meal quality. The soybean genome has been fully sequenced, which provides opportunities for cross-species comparison of gene families of interest and identification of candidate genes in soybean. The cloned cDNAs of putative genes were expressed in Escherichia coli to produce recombinant enzymes. Through biochemical assays, these proteins were proved to be soybean salicylic acid methyltransferase (GmSAMT1), methyl salicylate esterase (GmSABP2-1), α[alpha]-farnesene synthase (GmTPS1) and E-β[beta]-caryophyllene synthase (GmTPS2), and endo-β[beta]-mannanase (GmMAN1). Through a transgenic hairy root system harboring overexpression of GmSAMT1 and GmSABP2-1, both of these two genes were evaluated for their biological function related to resistance against SCN. The results showed that the over-expression of GmSAMT1 and GmSABP2-1 in the susceptible soybean background lead to enhanced resistance against SCN. Among four putative soybean mannanase genes, one gene was cloned and characterized. GmMAN1 showed the endo-β[beta]-mannanase hydrolyse activity and can hydrolyze cell walls isolated from soybean seeds. In summary, using comparative and functional genomics, a number of genes involved in soybean defense and meal quality were isolated and characterized. This study provides novel knowledge and molecular tools for the genetic improvement of soybean for enhanced resistance and improved meal quality.

Η συγκόλληση των αιμοπεταλίων προάγεται από το ινωδογόνο, μια εξωκυττάρια πρωτεΐνη, η οποία δεσμεύεται εκλεκτικά στον υποδοχέα GP IIb/IIIa. Το τριπεπτίδιο RGD (Arg-Gly-Asp) συνιστά τη μικρότερη αλληλουχία, η οποία είναι απαραίτητη για την αναγνώριση και πρόσδεση του ινωδογόνου στον υποδοχέα και απαντάται και σε άλλες συγκολλητικές πρωτεΐνες, οι οποίες είναι παρούσες στον εξωκυττάριο χώρο και στο αίμα, όπως η ινοσυνδετίνη, το κολλαγόνο, ο παράγοντας Von Willebrand, κτλ. Η αντιπηκτική θεραπεία έχει βασιστεί σε δύο διαφορετικές προσεγγίσεις του προβλήματος. Η μία προσέγγιση αφορά την εμπόδιση της πρωταρχικής διέγερσης των αιμοπεταλίων από διάφορους αγωνιστές, όπως θρομβίνη, επινεφρίνη, κολλαγόνο, κτλ. Η άλλη προσέγγιση περιλαμβάνει την διακοπή του μηχανισμού μεταγωγής σήματος, ο οποίος ακολουθεί την πρόσδεση του αγωνιστή στην επιφάνεια των αιμοπεταλίων. Η ασπιρίνη, παράγωγο του σαλικυλικού οξέος, αναστέλλει το πρώτο βήμα στη βιοσύνθεση της θρομβοξάνης Α2 από αραχιδονικό οξύ μέσω ακετυλίωσης του ενζύμου κυκλοοξυγενάση 1. Στην παρούσα διατριβή πραγματοποιήθηκε ο σχεδιασμός και η σύνθεση γραμμικών και κυκλικών αναλόγων του τριπεπτιδίου RGD με ενσωματωμένο σαλικυλικό οξύ ή παράγωγά του. Τα διάφορα ανάλογα συντέθηκαν με κλασικές μεθόδους πεπτιδικής σύνθεσης σε υγρή και στερεά φάση. Τη σύνθεση των αναλόγων ακολούθησε καθαρισμός τους (HPLC) και προσδιορισμός της δομής τους με (ESI-MS). Στη συνέχεια, προσδιορίστηκε in vitro με φωτομετρική μέθοδο στους 37C και συνεχή καταγραφή της διερχόμενης ακτινοβολίας με ειδικό όργανο (Dual Channel Aggregometer) η ανασταλτική τους δράση στη συγκολλητικότητα των αιμοπεταλίων του ανθρώπου. Προς περαιτέρω επιβεβαίωση των πειραμάτων συσσώρευσης και μελέτη της πρόσδεσης των αναλόγων στις ιντεγκρίνες χρησιμοποιήθηκε η κυτταρομετρία ροής με μονοκλωνικά αντισώματα έναντι των υποδοχέων Gp Ia, Gp IIb/IIIa, Gp IIIa και GMp 140. Αναλύοντας τα αποτελέσματα των βιολογικών μελετών, τόσο της αναστολής της συσσωμάτωσης των αιμοπεταλίων του ανθρώπου in vitro όσο και της κυτταρομετρίας ροής σε ενεργοποιημένα αιμοπετάλια για τα δραστικά πεπτίδια, οδηγούμαστε στα επόμενα συμπεράσματα: 1. Από τη σειρά των RGD γραμμικών αναλόγων που μελετήθηκαν, βρέθηκαν δραστικά μόνο στην περίπτωση που τα πεπτίδια έχουν στο C-τελικό τους άκρο αμίδιο. 2. Η σύζευξη του σαλικυλικού οξέος στο τριπεπτίδιο - αμίδιο RGD ενισχύει την αντισυγκολλητική του δράση έναντι των αιμοπεταλίων in vitro. Από αυτά τα ανάλογα 26 (IC50= 50μΜ), 27 (38μΜ) και 28 (53μΜ) (ενσωματωμένο σαλικυλικό οξύ στο τριπεπτίδιο) έχουν την ισχυρότερη δράση, ενώ μόνο το τριπεπτίδιο 23 έχει IC50= 540μΜ 3. Η προστασία του β-καρβοξυλίου του Asp με βενζυλομάδα αυξάνει τη δράση του πεπτιδίου σε σχέση με την ύπαρξη ελεύθερου β-καρβοξυλίου. Αυτό διαπιστώνεται από το γεγονός ότι όλα τα βιολογικώς δραστικά ανάλογα έχουν το β-καρβοξύλιο προστατευμένο με βενζυλομάδα και αυτό έρχεται σε συμφωνία με βιβλιογραφικά δεδομένα άλλων ερευνητών περί αναγκαιότητας ύπαρξης λιπόφιλης ομάδας στο C-τελικό άκρο του πεπτιδίου. 4. Αντίθετα, η ενσωμάτωση σαλικυλο-παραγώγων (βρώμο-, χλώρο-, νίτρο-, άμινο-, κτλ) στα ανάλογα δίνει πολύ μικρή αντισυγκολλητική δράση στα αιμοπετάλια του ανθρώπου in vitro σε σχέση με το σαλικυλικό οξύ. 5. Από τα συντεθέντα κυκλικά ανάλογα μόνο το ανάλογο 61, που φέρει δισουλφιδικό δεσμό μεταξύ της κυστεΐνης και του θειοσαλικυλικού οξέος, επέδειξε ισχυρή αντισυγκολλητική δράση έναντι των αιμοπεταλίων του ανθρώπου in vitro με τιμή IC50= 8μΜ, που είναι και η καλύτερη τιμή IC50 για όλα τα ανάλογα που συντέθηκαν (γραμμικά και κυκλικά). 6. Και στην περίπτωση των κυκλικών πεπτιδίων, τα ανάλογα με το προστατευμένο β-καρβοξύλιο εμφανίζουν ισχυρότερη ανασταλτική δράση έναντι εκείνων που φέρουν το β-καρβοξύλιο ελεύθερο. 7. Από όλα τα γραμμικά ανάλογα που περιέχουν παράγωγα του σαλικυλικού οξέος το ανάλογο 39 που περιέχει το 5-χλωρο σαλικυλικό οξύ εμφανίζει ισχυρή ανασταλτική δράση έναντι του υποδοχέα Gp Ib. 8. Τέλος, θα πρέπει να αναφερθεί ότι είναι η πρώτη φορά που συνθετικά πεπτιδικά ανάλογα του RGD εμφανίζουν ισχυρή πρόσδεση στον υποδοχέα Gp Ib, o οποίος ευθύνεται για την προσκόλληση των αιμοπεταλίων στο κυτταρικό τοίχωμα. / Integrins constitute a large family of heterodimeric cell-surface, transmembrane receptors, which play a major role in cell/cell and cell/matrix adhesive interactions. The Arg-Gly-Asp (RGD) sequence is known to be the integrin recognition site of many extracellular matrix proteins such as fibronectin, osteopontin, collagen, fibrinogen, von Willebrand factor, laminin, etc. On the other hand, it is well known that low doses of aspirin (acetyl salicylic acid) decrease platelet aggregation by causing an inhibitory effect on thromboxane A2 production by platelets. Several antiplatelet strategies have already been developed and are under preclinical or clinical investigation. In the present thesis, the synthesis of linear and cyclic RGD analogs incorporating salicylic acid derivatives is reported. The syntheses of the new analogs were carried out by using classic methods of peptide synthesis in liquid or solid phase. The synthesized compounds were purified by RP-HPLC and lyophilised to give fluffy solid, identified by ESI-MS spectra. These compounds were tested for inhibitory activity on human platelet aggregation in vitro, by adding common aggregation reagents to citrated platelet rich plasma (PRP). The aggregation was determined using a dual channel electronic aggregometer by recording the increase of light transmission. Their specificity for the Gp receptors was checked by using flow cytometry with monoclonal antibodies against Gp Ib, Gp IIb/IIIa, Gp IIIa and GMP140 receptors. Based on the results of the biological studies we could report the next inferences: 1. From the studied synthetic RGD analogs only peptides – amides are active against human platelet aggregation in vitro. 2. The coupling of salicylic acid with the RGD peptides enforces the antiplatelet activity in vitro of the single tripeptide. From the above peptides, the analog 26 (tripeptide incorporating salicylic acid) shows strong antiplatelet activity (IC50=50 μΜ), whereas the analog 23 (only tripeptide) has IC50= 540μΜ. 3. The protection of the β-carboxy group of Asp as benzylester increases the activity of the peptides in comparison with those having the β-carboxy group unprotected. Thus, our results ensure the theory of necessity of the existence a lipophile center on the C-terminal side of the peptide. 4. The incorporation of salicylic acid derivatives in the RGD peptide does not increase further the antiplatelet activity than the incorporation of salicylic acid does. 5. Among the cyclic RGD peptides only the analog 61, having the disulfide bridge between the cysteine and the thiosalicylic acid, shows strong antiplatelet activity in vitro (IC50= 8μΜ). 6. Most of the analogs show high binding affinity for the Gp Ib receptor. The cyclic analog 61 shows special selectivity for this receptor at concetrations of 110 μΜ. 7. The analog 39, although it shows low antiplatelet activity, has high binding affinity for the Gp Ib receptor. Probably, this activity is due to the atom of Cl at the 5 position of aromatic ring of salicylic acid. 8. According to the literature data, it is the first time that synthetic RGD peptides show strong binding affinity for the Gp Ib receptor, which is responsible for the platelet adhesion to the subenthothelium.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / An efficient method to obtain six 4-alkoxy-2-oxo-but-3-enoic acid ethyl esters [EtO2CC(O)C(R2)=C(R1)OR, where R1/R2/R = Me/H/Me (2a), Ph/H/Me (2b), 4-MeC6H4/H/Me (2c), 4-BrC6H4/H/Me (2d), 4-FC6H4/H/Me (2e), H/Me/Et (2f)] from acylation of enol ethers or acetals with ethyl oxalyl chloride is reported. The cyclocondensation reaction of these substrates and their trifluormethylated analogues (5a-f) [CF3C(O)C(R2)=C(OR)R1] with salicylic hydrazide furnished a series of ethyl 5-hydroxy-1-(2-hydroxybenzoyl)-4,5-dihydro-1H-pyrazole-5-carboxylates (6) and 5-hydroxy-5-trifluoromethyl-4,5-dihydro-1H-1-(2-hydroxybenzoyl)pyrazoles (7), respectively. The structure of the obtained compounds was determined by spectroscopy and confirmed by crystallographic studies. The design of these compounds explore the hypothesis that the hybridization of salicylic acid with an appropriate 4,5-dihydro-1Hpyrazole scaffold can supply novel potent analgesic agents. The oral administration of one compound of each series of pyrazoles (6a, 7a) caused significant analgesia in the writhing test in mice, which was similar to the analgesia caused by aspirin. / Este trabalho descreve um eficiente método para obter seis 4-alcóxi-2-oxo-3-butenoatos de etila [EtO2CC(O)C(R2)=C(R1)OR, onde R1/R2/R = Me/H/Me (2a), Ph/H/Me (2b), 4-MeC6H4/H/Me (2c), 4-BrC6H4/H/Me (2d), 4-FC6H4/H/Me (2e), H/Me/Et (2f)] a partir da acilação de enoléteres e acetais com cloreto de etil oxalila. A reação de ciclocondensação desses substratos e seus análogos trifluormetilados (5a-f) [CF3C(O)C(R2)=C(OR)R1] com salicil hidrazida forneceu respectivamente as séries de 5-etilcarboxilato-5-hidróxi-4,5-diidro-1H-1-(2-hidroxibenzoil)pirazóis (6) e 5-hidróxi-5-trifluormetil-4,5-diidro-1H-1-(2-hidroxibenzoil)pirazóis (7). Adicionalmente aos dados espectroscópicos, a estrutura dos compostos foi confirmada por experimentos de raios-X. O planejamento desses compostos explora a hipótese de que a hibridização molecular do ácido salicílico com um núcleo 4,5-diidro-1H-pirazol pode fornecer novos potentes agentes analgésicos. A administração oral de um exemplo de cada série de pirazóis (6a, 7a) causou um efeito analgésico significante no teste das contorções abdominais em camundongos, o qual foi similar ao efeito analgésico apresentado pela aspirina.

Orientador: Luiz Felipe Valandro Soares / Coorientadora: Renata Marques de Melo Marinho / Banca: Marco Antonio Bottino / Banca: Paulo Francisco César / Banca: Estevam Augusto Bonfante / Banca: Lilian Costa Anami / Resumo: O objetivo deste estudo foi avaliar os efeitos de duas técnicas de gradação da zircônia no limite de fadiga de próteses parciais fixas (PPFs) de 03 elementos. Blocos pré-sinterizados de 3Y-TZP (zircônia policristalina parcialmente estabilizada por 3% mol de ítria) foram fresados para obter 69 PPFs, que foram divididas em 3 grupos (n = 23). O grupo controle (CTL) foi sinterizado e glazeado odedecendo os parâmetros usuais. Nos dois grupos experimentais as PPFs receberam sílica/vidro antes da sinterização. O grupo sílica sol-gel (SSG) foi graduado pela rota de processamento sol-gel, enquanto o grupo vidro-zircônia-vidro (GZG) foi graduado pela técnica de suspensão (slurry). Os grupos graduados não receberam a camada de glaze após a sinterização. Todas as PPFs foram cimentadas nos pilares de compósito com cimento resinoso de dupla polimerização, incluídas em poliuretano e armazenadas em água por cinco dias. A carga inicial do teste de fadiga foi calculada com base nos resultados do ensaio monotônico de três amostras de cada grupo. Para determinar o limite de fadiga 20 amostras de cada grupo foram submetidas ao método da escada ou staircase (100.000 ciclos/5 Hz). Os limites de fadiga (em Newton) foram: CTL = 1607,27; SSG = 1824,31; GZG = 2006,57 e o teste de Dixon e Mood indicou diferença estatística entre os grupos (intervalo de confiança de 95%). As infiltrações de sílica e vidro no corpo da zircônia, por dois diferentes métodos de gradação, aumentaram o limite de fadiga de PPFs... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The aim of this study was to evaluate the effects of two grading zirconia techniques on the fatigue limit of 3-unit fixed dental prostheses (FDPs). Presintered blocks of 3YTZP (3 mol% yttria-stabilized tetragonal zirconia polycrystal) were milled to obtain sixty-nine 3-unit FDPs, which were divided into three groups (n = 23). The control group (CTL) was sintered and glazed following the usual parameters. In the two experimental groups presintered FDPs received silica/glass before sintering. Silica sol-gel group (SSG) was graded by the sol-gel processing route, while the glasszirconia-glass group (GZG) was graded by a slurry technique. Graded groups did not receive a glaze layer after sintering. All FDPs were then luted with a dual-curing resin cement on composite abutments, embedded in polyurethane and stored in water for five days. The initial load of the fatigue test was calculated based on the results of the monotonic testing applied on three specimens of each group. To determine the fatigue limit, 20 samples of each group were subjected to staircase testing (100,000 cycles/5 Hz). The fatigue limits (in Newtons) were CT = 1607.27, SSG = 1824.31, and GZG = 2006.57, and the Dixon and Mood test indicated statistically significant differences among groups (95% confidence interval). The infiltration of silica and glass on zirconia bulk, by two different grading methods, increased the fatigue limits of monolithic zirconia FDPs / Doutor