Determinação e aplicações dos frutooligossacarídeos de Yacon (Smallanthus sonchifolius)

Torna-se cada vez mais importante fortalecer o vínculo entre o setor agrário, as universidades e o setor industrial. Através de estudos científicos pode-se aprimorar a produção agrícola, valorizar comercialmente os produtos manufaturados e permitir usos biotecnológicos anteriormente indisponíveis. Este trabalho ambicionou gerar dados que incentivassem e permitissem o suporte técnico-científico adequado ao pequeno e médio agricultor do litoral da Grande-Florianópolis, no estado de Santa Catarina (Brasil) viabilizando a exploração comercial das raízes de yacon (Smallanthus sonchifolius). Primeiro, o enfoque agronómico que objetivou ofertar dados científicos da adequação climática do plantio de yacon na região do litoral de Florianópolis (SC) com a finalidade de otimizar a produção e rentabilizá-la. Por cromatografia líquida de alta eficiência foram quantificados os valores de frutooligossacarídeos (fração de interesse, alimento funcional com efeito prebiótico), frutose, glucose e sacarose e avaliaram-se os efeitos diretos dos fatores climáticos na produção fazendo uso da análise multivariada para sua interpretação. Os resultados mostram que a produção de FOS não consegue atingir valores similares aos de outras regiões onde o yacon é explorado economicamente. Igualmente a produção de FOS parece ter uma grande dependência do clima, especialmente da amplitude térmica e da chuva. O segundo enfoque foi a possibilidade de exploração comercial, através de secagem em estufa. O processo de secagem, especialmente em amostras produzidas em condições climatológicas mais drásticas induzem modificações provocadas pela reacção de Maillard, como foi verificado por estudos de GCxGC-Tof-Ms e ESI-MS. O terceiro enfoque foi biotecnológico e consistiu em aproveitar frutooligossacarídeos comerciais para utilizá-los como matriz polimérica para produção de estruturas em escala nano e micrométrica através da eletropulverização. Foram observadas, nesta etapa, os aspetos morfológicos e as características das partículas formadas e a sua capacidade de servir como veículo transportador de compostos com características anti-oxidantes.

Laser assisted directional solidification of zirconia-based eutectics

Directionally solidified zirconia-based eutectic (DSE) fibres were obtained using the laser floating zone (LFZ) method. Two systems were investigated: zirconia-barium zirconate and zirconia-mullite. The purpose was to take advantage of zirconia properties, particularly as an ionic conductor and a mechanical rein-forcement phase. The influence of processing conditions in the structural and microstructural characteristics and their consequences on the electrical and mechanical behaviour were the focus of this thesis. The novel zirconia-barium zirconate eutectic materials were developed in order to combine oxygen ionic conduction through zirconia with protonic conduction from barium zirconate, promoting mixed ionic conduction behaviour. The mi-crostructure of the fibres comprises two alternated regions: bands having coarser zirconia-rich microstructure; and inter-band regions changing from a homogeneous coupled eutectic, at the lowest pulling rate, to columnar colony microstructure, for the faster grown fibres. The bands inter-distance increases with the growth rate and, at 300 mm/h, zirconia dendrites develop enclosed in a fine-interpenetrated network of 50 vol.% ZrO2-50 vol.% BaZrO3. Both phases display contiguity without interphase boundaries, according to impedance spec-troscopy data. Yttria-rich compositions were considered in order to promote the yttrium incorporation in both phases, as revealed by Raman spectroscopy and corroborated by the elemental chemical analysis in energy dispersive spectros-copy. This is a mandatory condition to attain simultaneous contribution to the mixed ionic conduction. Such results are supported by impedance spectrosco-py measurements, which clearly disclose an increase of total ionic conduction for lower temperatures in wet/reduction atmospheres (activation energies of 35 kJ/mol in N2+H2 and 48 kJ/mol in air, in the range of 320-500 ºC) compared to the dry/oxidizing conditions (attaining values close to 90 kJ/mol, above 500 ºC). At high temperatures, the proton incorporation into the barium zirconate is un-favourable, so oxygen ion conduction through zirconia prevails, in dry and oxi-dizing environments, reaching a maximum of 1.3x10-2 S/cm in dry air, at ~1000 ºC. The ionic conduction of zirconia was alternatively combined with another high temperature oxygen ion conductor, as mullite, in order to obtain a broad elec-trolytic domain. The growth rate has a huge influence in the amount of phases and microstructure of the directionally solidified zirconia-mullite fibres. Their microstructure changes from planar coupled eutectic to dendritic eutectic mor-phology, when the growth rate rises from 1 to 500 mm/h, along with an incre-ment of tetragonal zirconia content. Furthermore, high growth rates lead to the development of Al-Si-Y glassy phase, and thus less mullite amount, which is found to considerably reduce the total ionic conduction of as-grown fibres. The reduction of the glassy phase content after annealing (10h; 1400 ºC) promotes an increase of the total ionic conduction (≥0.01 S/cm at 1370 °C), raising the mullite and tetragonal zirconia contents and leading to microstructural differ-ences, namely the distribution and size of the zirconia constituent. This has important consequences in conductivity by improving the percolation pathways. A notable increase in hardness is observed from 11.3 GPa for the 10 mm/h pulled fibre to 21.2 GPa for the fibre grown at 500 mm/h. The ultra-fine eutectic morphology of the 500 mm/h fibres results in a maximum value of 534 MPa for room temperature bending strength, which decreases to about one-fourth of this value at high temperature testing (1400 ºC) due to the soft nature of the glassy-matrix.

Percepção e valores das comunidades tradicionais no processo de desenvolvimento

Esta tese constitui uma reflexão sobre uma realidade, a praia do Francês, Alagoas, Brasil, que após mais de uma década é agora revisitada demonstrando os impactos socioambientais evidenciados ao longo de 30 anos, e por sua vez, fazem com que esta praia se transforme em laboratório cuja análise desenvolvida poderá servir como exemplo para ações futuras, e sustentáveis, em outras localidades. Sobretudo para áreas encontradas no mundo periférico, subdesenvolvido ou no Sul do Mundo, caracterizadas pela presença de populações tradicionais com seu rico e variado conhecimento, oralmente transmitido, adquirido através de suas observações práticas e cotidianas com seu meio circundante. Porém, este conhecimento encontra-se ameaçado pelo atual padrão de modernização, homogeneização do mundo, que em seu processo de desenvolvimento exclui crenças, valores e percepções de comunidades tradicionais inteiras, uma vez que se caracteriza por ocorrer com ausência de um olhar atento as especificidades locais, onde estas populações são as primeiras a sofrer com o atual modelo imposto que as ignora por completo e, ao mesmo tempo, por ocorrer com anuência do poder público local. Ao ignorá-las, tais ações minam suas formas de subsistência e via de consequência, às exclui das áreas onde sempre viveram e preservaram fazendo com que um importante e aprofundado conhecimento se perca, juntamente com a desintegração de seus laços de sociabilidade. A exemplo do Arquipélago dos Bijagós, Guiné-Bissau, costa Atlântica da África, lugar de existência de importante população tradicional que, a exemplo de outras localidades do mundo periférico, começa a experimentar transformações em seu patrimônio natural e cultural, decorrentes de ações desconectadas da realidade local. Este estudo, acena para uma importante reflexão sobre os impactos observados nesta realidade e os evidenciados na Praia do Francês. Portanto, procura-se aqui demonstrar a importância do conhecimento e das práticas existentes nas populações tradicionais (autóctones) para ações futuras, onde a inclusão deste saber seja prioridade para outras formas de pensar o desenvolvimento; e em seu processo de construção/planejamento este ocorra: com base no respeito à diversidade e com a participação dos mais diferentes e importantes atores. Enfim, um processo de desenvolvimento de base local, endógeno, sustentável.

Oxidation and glycoxidation of phosphatidylserine and their effect in immune response : a lipidomic approach

Phosphatidylserine (PS) is a member of the class of phospholipids, and is distributed among all cells of mammalians, playing important roles in diverse biological processes, including blood clotting and apoptosis. When externalized, PS is a ligand that is recognized on apoptotic cells. It has been considered that before externalization PS is oxidized and oxPS enhance the recognition by macrophages receptors, however the knowledge about oxidation of PS is still limited. PS, like others phospholipids, has two fatty acyl chains and one polar head group, in this case is the amino acid serine. The modifications in PS structure can occur by oxidation of the unsaturated fatty acyl chains and by glycation of the polar head group, due to free amine group, thus increasing the susceptibility to oxidative events. The main goal of this work was to characterize and identify oxidized and glycoxidized PS, contributing to the knowledge of the biological role of oxidation products of PS, as well as of glycated PS, in immune and inflammatory processes. To achieve this goal, PS standards (1-palmitoyl-2-oleoyl-sn-glycero-3-phospho- L-serine (POPS), 1,2-dipalmitoyl-sn-glycero-3-phospho-L-serine (DPPS), 1- palmitoyl-2-linoleoyl-sn-glycero-3-phospho-L-serine (PLPS) and 1-palmitoyl-2- arachidonoyl-sn-glycero-3-phospho-L-serine (PAPS)) and glycated PS (PAPS and POPS) were induced to oxidize in model systems, using different oxidant reagents: HO• and 2,2'-azobis-2-methyl-propanimidamide dihydrochloride (AAPH) . The detailed structural characterization of the oxidative products was performed by ESI-MS and MS/MS coupled to separation techniques such as off line TLC-MS and on line LC-MS, in order to obtained better characterization of the larger number of PS and glycated PS oxidation products. The results obtained in this work allowed to identify several oxidation products of PS and glycated PS with modifications in unsaturated fatty acyl chain. Also, oxidation products formed due to structural changes in the serine polar head with formation of terminal acetamide, terminal hydroperoxyacetaldehyde.and terminal acetic acid (glycerophosphacetic acid, GPAA) were identified. The mass spectrometric specific fragmentation pathway of each type of oxidation product was determined using different mass spectrometry approaches. Based on the identified fragmentation pathways, targeted lipidomic analysis was performed to detect oxidation products modified in serine polar head in HaCaT cell line treated with AAPH. The GPAA was detected in HaCaT cells treated with AAPH to induce oxidative stress, thus confirming that modifications in PS polar head is possible to occur in biological systems. Furthermore, it was found that glycated PS species are more prone to oxidative modifications when compared with non glycated PS. During oxidation of glycated PS, besides the oxidation in acyl chains, new oxidation products due to oxidation of the glucose moiety were identified, including PS advanced glycation end products (PSAGES). To investigate if UVA oxidative stress exerted changes in the lipidome of melanoma cell lines, particularly in PS profile, a lipidomic analysis was performed. The lipid profile was obtained using HILIC-LC-MS and GC-MS analysis of the total lipid extracts obtained from human melanoma cell line (SKMEL- 28) after UVA irradiation at 0, 2 and 24 hours. The results did not showed significant differences in PS content. At molecular level, only PS (18:0:18:1) decreased at the moment of irradiation. The most significant changes in phospholipids content occurred in phosphatidylcholines (PC) and phosphatidylinositol (PI) classes, with an increase of mono-unsaturated fatty acid (MUFA), similarly as observed for the fatty acid analysis. Overall, these data indicate that the observed membrane lipid changes associated with lipogenesis after UVA exposure may be correlated with malignant transformations associated with cancer development and progression. Despite of UVA radiation is associated with oxidative damage, in this work was not possible observe oxidation phospholipids. The anti/pro-inflammatory properties of the oxidized PLPS (oxPLPS) versus non-oxidized PLPS were tested on LPS stimulated RAW 264.7 macrophages. The modulation of intracellular signaling pathways such as NF-kB and MAPK cascades by oxPLPS and PS was also examined in this study. The results obtained from evaluation of anti/pro-inflammatory properties showed that neither PLPS or oxPLPS species activated the macrophages. Moreover only oxidized PLS were found to significantly inhibit NO production and iNOS and il1β gene transcription induced by LPS. The analysis at molecular level showed that this was the result of the attenuation of LPS-induced c-Jun-N-terminal kinase (JNK) and p65 NF-kB nuclear translocation. Overall these data suggest that oxPLPS, but not native PLPS, mitigates pro-inflammatory signaling in macrophages, contributing to containment of inflammation during apoptotic cell engulfment. The results obtained in this work provides new information on the modifications of PS, facilitating the identification of oxidized species in complex samples, namely under physiopathologic conditions and also contributes to a better understanding of the role of oxPS and PS in the inflammatory response, in the apoptotic process and other biological functions.