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
NMR studies of tetrahaem cytochomes from D. desulfuricans and S. frigidimarina
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Heat stress adaptation in hyperthermophiles: bosynthesis of inositol-containing compatible solutes
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
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Metabolism of primary astrocytes studied by NMR: metabolic trafficking and neuroprotection
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.
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Insights into the molecular mechanisms of protein stabilization by osmolytes of hyperthermophiles
Title: Insights into the molecular mechanisms of protein stabilization by osmolytes of hyperthermophiles
Authors: Pais, Tiago Vasconcelos Duarte Moreira
Description: Dissertation presented to obtain the Ph.D degree in Biochemistry
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Osmo- and thermo-adaptation in hyperthermophilic Archaea: identification of compatible solutes accumulation profiles, and biosynthetic routes in Archaeoglobus spp.
Title: Osmo- and thermo-adaptation in hyperthermophilic Archaea: identification of compatible solutes accumulation profiles, and biosynthetic routes in Archaeoglobus spp.
Authors: Gonçalves, Luís Pedro Gafeira
Abstract: Hyperthermophilic organisms have optimum growth temperatures above 80°C and belong to genera that are placed near the root of the Tree of Life, in short phylogenetic branches within the domains Bacteria or Archaea. Although hyperthermophiles have been isolated from a variety of hot environments, most species originate from marine geothermal areas, hence they are slightly halophilic. The accumulation of low-molecular mass organic solutes, i. e., compatible solutes, is one of the most common strategies developed by cells to cope with fluctuations of the salinity of the medium. Interestingly, in marine hyperthermophiles, compatible solute accumulation occurs not only in response to an increase in the external salt concentration, but also in response to supraoptimal growth temperatures. Moreover, microorganisms adapted to grow optimally at elevated temperatures tend to use negatively charged solutes that are not present or rarely encountered in mesophilic organisms.(...)
Description: Dissertation presented to obtain the Ph.D degree in Biochemistry
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Electron Transfer and Ligand Binding Properties of Cytochromes
Título: Electron Transfer and Ligand Binding Properties of Cytochromes
Autor: Quintas, Pedro Oliveira
Resumo: Haem proteins are one of the most versatile groups of proteins in nature. They
are able to perform several functions, such as transport and storage of oxygen, electron
transfer, sensing of small molecules, and catalysis. The nature of the haem, the
presence or absence and the nature of the axial ligands to the iron atom, and the effect
of the polypeptide chain of the protein on the environment of the haem all contribute
to this versatility. The work presented in this thesis focuses on the mechanisms of
electron transfer and the discrimination of small ligands by cytochromes containing
haem c with axial histidines.(...)
Descrição: Dissertation presented to obtain the Ph.D degree in Biochemistry
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Insights into the biochemical strategies of adaptation to heat stress in the hyperthermophilic archaeon Pyrococcus furiosus
Título: Insights into the biochemical strategies of adaptation to heat stress in the hyperthermophilic archaeon Pyrococcus furiosus
Autor: Esteves, Ana Maria
Resumo: Organisms that thrive optimally at temperatures above 80°C are called
hyperthermophiles. These prokaryotes have been isolated from a variety of
hot environments, such as marine geothermal areas, hence they are
usually slightly halophilic. Like other halophiles, marine hyperthermophiles
have to cope with fluctuations in the salinity of the external medium and
generally use low-molecular mass organic compounds to adjust cell turgor
pressure. These compounds can accumulate to high levels without
interfering with cell metabolism, thereby deserving the designation of
compatible solutes. Curiously, the accumulation of compatible solutes also
occurs in response to supraoptimal temperatures.(...)
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Metabolic engineering of Corynebacterium glutamicum for the production of succinate and 2,3-butanediol
Título: Metabolic engineering of Corynebacterium glutamicum for the production of succinate and 2,3-butanediol
Autor: Rados, Dusica
Resumo: The depletion of fossil raw materials and the environmental pollution
associated with their processing motivated the development of alternative
methods for production of fuels and bulk chemicals. The solution offered by
White Biotechnology is to produce these chemicals from biomass, a
renewable resource rich in carbohydrates, using microorganisms as
biocatalysts. Corynebacterium glutamicum is a well-known industrial
bacterium employed for decades in the large scale production of L-amino
acids. In this work, the potential of C. glutamicum as a bio-platform for the
production of succinate and 2,3-butanediol was explored.(...)
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Insights into the molecular mechanisms of protein stabilization by osmolytes of hyperthermophiles
Título: Insights into the molecular mechanisms of protein stabilization by osmolytes of hyperthermophiles
Autor: Pais, Tiago Vasconcelos Duarte Moreira
Descrição: Dissertation presented to obtain the Ph.D degree in Biochemistry
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