http://hdl.handle.net/10362/3549 2013-06-19T08:58:34Z http://hdl.handle.net/10362/6845 Title: Metabolism of primary astrocytes studied by NMR: metabolic trafficking and neuroprotection Authors: Fonseca, Luís Lopes Abstract: The human brain is the product of 600 million years of evolution and it is by far the most complex structure in the known universe. The vertebrates’ brain is composed of several different cell types, which perform the different functions required. The two most abundant cell types are neurons, which are the brain function unit, and glial cells, which are responsible for a myriad of housekeeping, homeostatic and structural functions. Glial metabolism is so far interconnected with the neuronal metabolism, that it is difficult to state where one finishes and the other starts. Trafficking between the two compartments include metabolites of almost all metabolic pathways (glycolysis, TCA, amino acids, ketone bodies, etc) and also ions.(...) Description: Dissertation presented to obtain a Ph. D. degree in Biochemistry by Universidade Nova de Lisboa, Instituto de Tecnologia Química e Biológica. 2006-09-01T00:00:00Z http://hdl.handle.net/10362/6184 Title: Heat stress adaptation in hyperthermophiles: bosynthesis of inositol-containing compatible solutes Authors: Rodrigues, Marta Viseu Abstract: The accumulation of low-molecular mass organic compounds, named compatible solutes, is an efficient, widespread strategy to counterbalance increases in the external osmolarity, thereby preserving cell viability. The intracellular accumulation of compatible solutes also occurs in response to supra-optimal temperatures, and this observation led to the assumption that they play a role in the thermoadaptation process. Hyperthermophiles, organisms with optimal growth temperatures above 80ºC, have been isolated from a variety of hot habitats. Many hyperthermophiles thrive in marine geothermal areas and are slightly halophilic. As a result, they have to cope with fluctuations in the salinity of the external medium and generally accumulate compatible solutes as a defense strategy. Interestingly, these hyperthermophilic organisms show a clear preference for negatively charged solutes, such as diglycerol phosphate, di-myo-inositol 1,3’-phosphate and mannosylglycerate, over neutral or zwitterionic solutes typically found in mesophiles (glycerol, trehalose, myo-inositol, and ectoines). The question then arises whether those charged solutes were selected by organisms adapted to grow at high temperatures because they are more suitable to protect proteins and other cell components against thermal denaturation.(...) Description: Dissertation presented to obtain the Ph.D. degree in Biochemistry 2011-07-01T00:00:00Z http://hdl.handle.net/10362/5244 Title: NMR studies of tetrahaem cytochomes from D. desulfuricans and S. frigidimarina Authors: Paixão, Vítor Bordona Abstract: Tetrahaem cytochromes are small soluble proteins with four non-planar haems with bis-histidinyl axial coordination that were first isolated from Desulfovibrio vulgaris in the 1950s and subsequently in several other bacteria. Even though the sequence homology, the amino acid composition and the thermodynamic properties of the several tetrahaem cytochromes may be different; the overall haem core architecture and the general fold of the protein established by X-ray crystallography and nuclear magnetic resonance (NMR) are highly conserved.(...) Description: Dissertation Presented to obtain the Ph.D. in Biochemistry 2010-09-01T00:00:00Z