CHEMISTRY OF BIOLOGICAL MACROMOLECULES

Author: CASTILLEJO SANCHEZ MARIA ANGELES.
Year: 2005.
University: CÓRDOBA [www.uco.es].
Place of defense: FACULTAD DE CIENCIAS.
Place of preparation: FACULTAD DE CIENCIAS.

Summary: By approximating proteomics has studied the molecular basis of the response of plants to biotic and abiotic stress, using the following systems of study: - The experimental system model, Medicago truncatula, which studies have addressed response to phytopathogenic fungi (Uromyces striatus, rust) and parasitic plants (Orobanche crenata, jopo). The Pisum sativum - legume (pea), which has studied the response to parasitic plants (Orobanche crenata, jopo). The Sunflower oil (sunflower), which have conducted studies of response to drought. The specific objectives for each of the systems have been:-Establish differences in protein profiles between genotypes and / or treatments. - Identify proteins and genes response to drought, phytopathogenic fungi and parasitic plants. - To characterize mechanisms of resistance and tolerance to biotic and abiotic stress, differentiating specific species or stress. As a methodology different protocols have been used for extracting protein root and leaves, which are optimized for each system, the separation of proteins by two-dimensional electrophoresis and staining techniques. The proteins expressed differentially between genotypes or treatment have been identified by mass spectrometry (MALDI-TOF) and database searches of protein or DNA using a search engine (algorithms). The results validate the techniques used, estableciéndose changes in protein expression between genotypes in response to treatment. Some of the differential protein have been identified:-Medicago truncatula (cv. Paraggio) in response to inoculation with Uromyces striatus there is a small number of differentially expressed proteins, which have been identified as malato dehydrogenase, glutathione transferase and glutathione peroxidase . - Pea (genotypes Messire and Ps624) and Medicago truncatula (genotypes SA4087 and SA27774) in response to inoculation with Orobanche crenata, there are two clear trends among genotypes studied. In susceptible genotypes of both plants showed a decrease of enzymes of energy metabolism. However, the genotypes resistant show an increase of proteins identified as proteins of defense against pathogens and protein response to stress. - Sunflower (genotypes 5257 and 5270) in response to drought occurs primarily, a decrease of enzymes of photosynthesis and metabolism of carbohydrates in the susceptible genotype, not to appreciate the resilient.

Author: BLANCO CANOSA JUAN BAUTISTA.
Year: 2005.
University: SANTIAGO DE COMPOSTELA [www.usc.es].
Place of defense: FACULTAD DE QUÍMICA.
Place of preparation: FACULTAD DE QUÍMICA.

Summary: The dissertation deals with the synthesis and study of similar peptídicos of Natural Transcription factors, proteins that are responsible for regulating gene expression. The report describes the properties of various analogues of transcription factor GCN4 that can interact with its target sequence with similar affinities. These hybrids are similar in structure presented an alpha helix of this protein to recognize the major groove of DNA and molecular tripirrólica that interacts with the minor groove of a stream nearby.

Author: GÓMEZ BLANCO ALEJANDRO.
Year: 2005.
University: AUTÓNOMA DE BARCELONA [www.uab.es].
Place of defense: INSTITUTO DE BIOLOGÍA MOLECULAR DE BARCELONA.
Place of preparation: INSTITUTO DE BIOLOGÍA MOLECULAR DE BARCELONA.

Summary: The main way in which bacteria respond to environmental stimuli is done via two-component systems consisting of a histidine kinase and a regulatory response. PhoB is a transcriptional activator of this second type that controls phosphate uptake in Escherichia coli activating almost 40 genes. Its structure consists of two domains: a domain regulator fosforilable in an aspartate and a mastery of effector binding to DNA and transactivador (phoBE). The last contact with the subunit sigma70 of RNA polymerase to activate transcription. This subunit recognizes bacterial gene promoters housekeeping and structurally contains 4 domains. The domain 4 is the one that interacts with PhoBE. This paper describes the structures critalográficas of PhoBE as Apo, coupled with DNA and united factor sigma70, plus various biochemical experiments to complement the structural information and understand the mechanisms of the union Dna and activation of transcription. Thus, PhoBE contains a domain winged-helix who joins DAN dímero as a tandem entering the propellers of recognition in the major groove of DAN and Wings in the minor. The DNA is curved so soft 40Â ° and the curvature is due to an understanding of the minor groove from the wing. Direct contacts with the bases are established by the propeller of appreciation for the wing. And laterally exposed areas of interaction to join the domino 4 factor sigma70. Gel retardation experiments with promoters containing more than one pho box, show a hierarchical union and cooperative, so the union's first dímero facilitates the second. This is explained by the presence in the structure of dímero proteína-proteína.

Author: YANES TORRADO OSCAR.
Year: 2006.
University: AUTÓNOMA DE BARCELONA [www.uab.es].
Place of defense: SALA DE ACTOS DE LA FACULTAD DE CIENCIAS.
Place of preparation: UNIVERSIDAD AUTÓNOMA DE BARCELONA.

Summary: THESIS ON THIS IS DIFFERENT DESCRIBE APROXIMACIONES COMPLEX TO DETECT NOT COVALENTES BETWEEN PROTEINS BY ESPECTROMETRÍA OF MASSES MALDI-TOF. ESPECIALLY, THOSE THAT ARE AMONG PROTEASAS AND DAN INHIBITORS PROTEASAS PROTEICOS IN BIOLOGICAL SAMPLES.

Author: RICO MARTÍN ALBERTO JOSÉ.
Year: 2006.
University: VALLADOLID [www.uva.es].
Place of defense: FACULTAD DE MEDICINA.
Place of preparation: FACULTAD DE MEDICINA.

Summary: The adrenal medulla secret catecholamines compared to physiological stimuli such as hypoxia during the perinatal stage in a non-neurogenic, species such as rats or humans where the innervation esplácnica is not yet functional. This release of catecholamines reaches its highest peak concentration during childbirth and is essential for adaptation to life extrauterina newborn. We used a preparation of adrenal medulla in vitro rat to study through microamperometría using microelectrodos carbon fiber catecholamine secretion of this body during your newborn stage to confront a physiological stimuli such as hypoxia, hypercapnic acidosis and hypoglycemia. In this way we have described in this Doctoral Thesis secretory response of the adrenal medulla neonatal rats induced by hypoxia. This response is dependent on the intensity of hypoxia applied and extracellular calcium to enter the cell cromafín through essentially channel type L. When comparing the response to that described in the carotid body, an organ quimiorreceptor better studied, we observed as a gain of the transduction hypoxic to activate machinery exocitótica is lower in the neonatal adrenal medulla in the carotid body in adult rats. This response hypoxic not nurogénica in the adrenal medulla is mitigated to be in a 30% in the bone marrow of rats youth and inervada, and disappears in the marrow of adult rats, the disappearance does not appear due to the opioid peptides secreted by the nerve endings. We describe for the first time in vitro response of the non-neurogenic neonatal adrenal medulla in front of the hypercapnic acidosis. The release of catecholamine-induced physiological stimulus this is of similar magnitude to that caused by hypoxia, and as in the case of the latter, dependent on the presence of extracellular calcium. This response induced hypercapnic acidosis in rats is attenuated youth and inervadas. In addition to subjecting the neonatal adrenal medulla to stimuli combined hypoxia and hypercapnic acidosis simulating the physiological status of suffocation, as we see there is an effect rather than summation in the release of catecholamines. This effect is also present in the rat adrenal medulla youth but dimmed. By measuring blood glucose in rats and during neonatal development postanatal, we found that rats born hypoglycaemic. The heart of newborn rats increases their secretion of catecholamines to deal with low glucose stimulation, this release is dependent on the degree of hypoglycemia applied and the presence of extracellular calcium entering the cell primarily through channels kind L. In addition, we observed in our study as hypoglycemia power secretory response induced by hypoxia, this empowerment depends on the degree of hypoxia and hypoglycemia applied and the presence of extracellular calcium, which enter into the cell cromafín neonatal primarily through L-type channels . This enhancement is due to the interaction between hypoxia and hypoglycemia in stages prior to the depolarization and potassium channels sensitive to TEA or 4-aminopyridine not appear to intervene in this empowerment of hypoxia by hypoglycemia, nor in the secretory response - induced hypoxia in the neonatal rat adrenal medulla. The empowerment of hypoxic response by hypoglycemia in the neonatal rat spinal cord is not due to an energy deficit because it keeps the extra fructose or Pyruvate, nor inhibiting the path of pentosas phosphate. Besides the presence of glucose analogues that interaccionarían with molecules or mechanisms with affinity for the substrate nor prevents empowerment. Data presented in this paper show that the enormous peak catecholamines occurred dur 8 to 44c vaginal birth is so important for the adaptation to life and extrauterina attributed to hypoxia, is due to synergism between hypoxia and hypercapnic acidosis and empowerment of hypoxia by hypoglycemia, situations all too common during childbirth. What we question whether it is appropriate to correct hypoglycemia within certain limits in order to facilitate a good adaptation in the newborn.