MICROBIOLOGY (3)

Author: Pérez Rama Mónica.
Year: 2005.
University: A CORUÑA [www.udc.es].
Place of defense: Facultad de Ciencias.
Place of preparation: Facultad de Ciencias.

Summary: Cadmium inhibits the growth of marine microalgae Tetraselmis suecica. This effect is proportional to the concentration of this metal, with its EC50 after 6 days of exposure of 7.9 mg Cd / L. However, there was a stimulative effect of cadmium when cells are exposed to low concentrations of the same (0.6 and 3 mg Cd / L) in the early days of cultivation; this effect ose known as "hormesis." As a consequence of exposure to cadmium cells Tetraselmis suecica synthesize compounds that thiol groups present, joining most of the metal intracellular these compounds. Some of these compounds have been identified as fitoquelatitas acting as a protective mechanism of this microalgae compared to the toxicity of cadmium. For the identification of these compounds tiólicos not protein developed a new technique of capillary electrophoresis compounds tiólicos derivatizados with mBrB in complex biological samples. The conditions electroforéticas used to optimize the separation were:-Electrolyte: 150 mM H3PO4pH 1.60 and 2.5% methanol (v / v). - Terms of capillary electrophoresis: 13 kV, capillary 30 cm length effectively (38 cm in total length) with 50 m internal diameter x 375 m OD. The injection was performed using pressure of 50 mbar exercised over 17s. The detection is performed by measuring the absorbance at a wavelength of 390nm. The conditions set forth in this paper allow for a quick analysis, reproducible and sensitive compounds tiólicos (including fitoquelatinas) in crude extracts of biological samples using a detector UV / vis. The synthesis of fitoquelatinas is an effective defense mechanism in response to cadmium, but only with concentrations of the metal below the values of EC50. When the concentration of cadmium exceeding this value, the toxic effect of cadmium blocks the synthesis of fitoquelatinas, with the amino acid cysteine the main chelating agent. However, the cysteine has a low capability of the metal chelation so this animoácido not avoid toxicity caused by high concentrations of cadmium in the middle. A second family of peptides tiólicos was characterized in Tetraselmis suecica, fitoquelatinas desgliciladas with the overall structure of (y-Glu-Cys) n. Like the fitoquelatinas, fitoquelatinas desgliciladas appear after exposure to cadmium, therefore, could also be acting on the detoxification of this metal. Tetraselmis suecica cells are capable of baicumular and bioadsorber cadmium allowing its withdrawal from the medium. This microalgae has shown a great capacity for extraction of cadmium, which is significant extraction from the first day. The great strength of Tetraselmis suecica to camio because of its ability synthesis fitoquelatinas that bind the metal so innocuous, and their ability to accumulation of this metal, make this a good candidate for Micro can be used in the process of extracting cadmium - contaminated water.

Author: ROJAS REMÓN LAURA.
Year: 2005.
University: BARCELONA [www.ub.es].
Place of defense: FACULTAD DE MEDICINA.
Place of preparation: FACULTAD DE FARMACIA, UNIVERSIDAD DE BARCELONA.

Summary: As a general objective of this thesis we have the molecular and functional characterization of the mechanisms of resistance in Gram negative bacteria original clinical multidrug: Morganella morganii HUB198351. The mechanisms of resistance of bacteria to antibiotics may be different. From enzymatic inactivation of the antibiotic, changing the target of the antibiotic, as well as the decrease in membrane permeability, the expression of bomabas reflux and the exchange of genetic material by transferring plasmids, transposons or integrones. Precisely latter mechanisms were the subject of this thesis, we investigate the existence of integrones the strain of multidrug Morganella morganii and obtained sequences of four resistance genes inserted into two integrones plasmid. To determine whether the resistance to some antibiotics could be attributed to the action of reflux pump tests were conducted to study the functionality of the bomabas reflux that might expel antibiotics outside the cells. The experiments demonstrated the existence of a bomb reflux functional. Subsequently analyzed the outer membrane proteins of M.morganii. The analysis conductacia single channel produced by the protein Omp36 of Mmorganii and measures of membrane potential to zero flow, confirmed that it is a protein forming channel conductance with values of 2nS with a slight cationic selectivity and size Pore of 1.18 nm.

Author: VILLANUEVA ÁLVAREZ LAURA.
Year: 2005.
University: BARCELONA [www.ub.es].
Place of defense: FACULTAD DE BIOLOGÍA - UNIVERSIDAD DE BARCELONA.
Place of preparation: FACULTAD DE BIOLOGÍA - UNIVERSIDAD DE BARCELONA.

Summary: The microbial mats are stable ecosystems that have great diversity, which are a source of microorganisms not marked and adapted to the microbial community. Although there have been many studies of microbial mats as a model of microbial ecosystem while there are many unknowns about the biochemical cycles, cooperative associations and the taxonomy of the members that make up this system. The main objective of this work was the implementation of new techniques and combining with others for obtaining an integrated overview of the structure and physiology, and analyze information gathered by them to characterize microbial populations involved in lesser-known but important processes. It can be concluded that the application of the technique of lipid biomarker signal has proven to be an effective method for obtaining information on such ecosystems. Furthermore, the combination of lipid analysis methods based on microbial nucleic acids at different stages in depth, has provided useful information on the spatial and temporal dynamics of populations and their taxonomic affiliation. This study has revealed the importance of bacteria heterotrofas in photosynthetic layer, the presence of green sulfur bacteria in a number of niches, and bacteria fermentadoras in the deeper layers. Moreover, the analysis of divergence have suggested that the changes related to the depth appear to have greater influence than the temporary changes. Analysis of quinones respiratory samples mats has provided estimates of biomass, taxonomic composition and redox state of the community. In this case, there have been significant differences in the structure of the community and the redox state of microbial mats in different location, and were apparently quite similar. In addition, it has conducted a preliminary screening on the composition of intact polar lipids that will be enhanced in the future because of its large potential taxonomic. Moreover, there has also been detected members of the Archaea domain in microbial mats that could play an important role in the physiology of the system. The above methodologies utilized in microbial mats for a circadian cycle to assess the response of the community to change daily. There was a pattern of physiological responses which was reproduced daily, which suggests that the microbial mats complex ecosystems are highly predictable. Moreover, it has highlighted the importance of the bacteria heterotrofas in regulating metabolic process of the layer fótica. In this paper, were isolated and characterized two strains photosynthetic microbial strains delas. We have shown the capabilities of metabolic Pseudoalteromonas sp. EDB and its relationship with cyanobacteria. Despite these, more work is needed to determine the exchange of nutrients between these groups. Moreover, has been characterized by a member of the genus Sphingomonas although it must determine its importance in the recycling of nutrients and in the dynamics of polihidroxialcanoatos. Finally, it has been determined the diversity of oxidadores of sulfur in the transition zone oxígeno-sulfhídrico. In this case, previous studies had described morphotypes espiriloides and spirochetes involved in the sulfur cycle. Therefore, it has been investigated in succession morphological these creicmientos to predict its reproducibility. The application of molecular techniques has provided important information about the composition of these systems and has enabled the design of probes that will be applied in the future to detect microorganisms found in rugs. In addition, it has been observed that microorganisms could be detected resistance structures or compounds accumulate reserves to environmental perturbations. Therefore, it is working in this line for the detection of such structures in natural samples.

Author: RODRÍGUEZ CARMONA ESCARLATA.
Year: 2005.
University: BARCELONA [www.ub.es].
Place of preparation: FACULTAT DE FARMÀCIA - UNIVERSITAT DE BARCELONA.

Summary: The PHAs are a biological family polyesters, optically active, containing monomer units acid hidroxialcanoicos (HAs) that accumulate as inclusions in many intracellular bacteria ranging from 30 to 80% of cellular dry weight. Los PHAs son productos naturales que son sintetizados y catabolizados por diferentes organismos y que poseen propiedades mecánicas similares a varios termoplásticos sintéticos, como el propileno. In this context, the present work has been used a byproduct Oily (WEICHOL), resulting from the distillation of industrial waste consisting of oleina palm and rapeseed oil for the production of biodegradable plastics or polihidroxialcanoatos (PHAs) by layer Pseudomonas aeruginosa 42 A2. The goals that arise are: 1 - The taxonomic identification of the bacterial strain Pseudomonas sp. 42 A2 by analyzing the gene sequence of 16S rRNA. 2 - The study of improving the culture medium, for biomass production and PHA in flasks, by applying the methodology of Response Surfaces by Pseudomonas aeruginosa 42A2 using WEICHOL as a source of carbon. 3, - The study of different production strategies pair wing obtaining biomass and PHA in bioreactor by Pseudomonas aeruginosa 42A2 using WEICHOL as a source of carbon. 4-structural characterization and physicochemistry of PHA synthesized by Pseudomonas aeruginosa 42A2 from byproduct Oily WEICHOL. Based on the results obtained in this study, can draw the following conclusions: 1 - The bacterial strain Pseudomonas sp. 42 A2 are taxonomically identified at the molecular level by analyzing the sequence of the gene coding for 16S rRNA as Pseudomonas aeruginosa 42A2. 2 - The application of the methodology Surface Response in the process of optimizing the culture medium used in flasks parala biomass production and PHA by Pseudomonas aeruginosa 42A2 using WEICHOL as a source of carbon, has enabled the development of two growth media different improving respectively, and biomass production and the production of PHA. 3-Of the processes carried out in bioreactor for obtaining biomass (crops of high cell density) and production of PHA by Pseudomonas aeruginosa 42A2 using the residue Oily WEICHOL as a source of carbon, it can be concluded that the diet of substrate determines in large measure the productivity of PHA. Similarly, the largest concentrations of PHA does not always correspond with the largest concentrations of biomass. Consequently the valuation of the preferred strategy must take into account the desirable balance between biomass production and the production of PHA, according to the purpose of the process. 4 - The monomer composition, average molecular weight and thermal properties of PHA produced by Pseudomonas aeruginosa 42A2 with the residue Oily WEICHOL, clearly reflect the composition of the source of carbon used. The components are monoméricos majority acid 3-hidroxidecanoico and acid 3-hidroxioctanoico, also observed the presence of unsaturated monomers. The PHA obtained by Pseudomonas aeruginosa 42A2 is a mcl-PHA amorphous with a relatively low molecular weight, an index of polidispersidad high and a low glass transition temperature, considering, as a consequence, an elastomer.

Author: DÁVILA FAJARDO CRISTINA LUCÍA.
Year: 2005.
University: COMPLUTENSE DE MADRID [www.ucm.es].
Place of defense: FACULTAD DE MADRID.
Place of preparation: CENTRO DE INVESTIGACIÓN BIOLÓGICAS (CSIC).

Summary: PPS10 is a plasmid replicon of Pseudomonas syringae which consists of a minimum origin of replication (oriV) and a gene repA coding for the protein that promotes trans plasmid replication. The protein is in balance monómerodímero solution. The dimers are joining the stream of the operator to control the expression of the protein RepA, while the monomers bind to sequences directly repeated began well plasmid replication. The passage of dimers to monomers is associated with a structural change in the protein. The objectives in this thesis are aimed at gaining more knowledge about this structural transformation: 1-study conformational changes between domains connected to the RepA interaction with the different DNA sequences using the technique of fluorescence spectroscopy, using as probe the single Trp residue of the protein and a fluorescent probe (IAEDANS). 2, - Studies of non-radiative energy transfer (FRET) between TRP94 and probe extrinsic IAEDANS.

Author: GARCÍA EFFRÓN GUILLEMO MANUEL.
Year: 2005.
University: COMPLUTENSE DE MADRID [www.ucm.es].
Place of defense: FACULTAD DE CIENCIAS BIOLÓGICAS.
Place of preparation: UNIVERSIDAD COMPLUTENSE DE MADRID.

Summary: From the decade of 80 has noticed a significant increase in the incidence of systemic fungal infections, which was accompanied by the extensive use of genetic azole antifungals. The clinical impact of the abuse of antimicrobial is widely known in bacteria and is important in the genre yeast Candida. Although the resistance in Aspergillus is a rare phenomenon, prophylaxis and therapy empirical inhibitor of 14 alpha sterol demetilasas associated with their use in agriculture, could facilitate the development of resistance to these secondary antifungal. On the other hand, Aspergillus spp. There are two genes (cyp51A and cyp51B), which codifies various enzymes 14-alfa sterol demetilasas. This fact, completely changes the study of resistance to azole antifungals as these would have two potential target. The mechanisms of resistance Aspergillus not been analyzed as in the case of Candida, so if there is an increase in resistance not dispondríamos the theoretical basis for developing tools for detecting or therapies effective against resistant organisms. Currently, it has been studied structurally enzyme Cyp51A of A.fumigatus using mathematical models but never functional study of both enzymes in order to determine their individual activity in A.fumigatus. For these reasons, this paper: 1-We studied the molecular mechanisms of resistance to azole antifungals in a collection of clinical isolates of A.fumigatus, describing two novel mechanisms of resistance to azole. 2-defective mutants were obtained in each of the individual and mutant enzymes with different mutations in the gene cyp51A, establishing the relationship between the enzyme Cyp51A with resistance to azole antifungals and the role of the morphological and structural work 14-alfa sterol demetilasa (Cyp51B). 3, is proposed - a technique for rapid diagnosis of resistance and opens the door for studying combinations anfúngicos azólcios as future therapeutic option of invasive aspergillosis supported in the good results obtained in vitro in this thesis. The conclusions obtained in this work, in addition to aid in the diagnosis and treatment of infections A.fumigatus, can be considered the first step in the process of developing new antifungal more potent and specific for each of the enzymes.

Author: IKKEN YOUSSEF.
Year: 2005.
University: COMPLUTENSE DE MADRID [www.ucm.es].
Place of defense: FACULTAD DE CIENCIAS BIOLÓGICAS.
Place of preparation: DPTO. NUTRICIÓN, BROMATOLOGÍA Y TECNOLOGÍA DE LOS ALIMENTOS, FAC. VETERINARIA, UCM.

Summary: The work done by Mr. Youssef Ikken, has had as its main objective to determine the potential antimutagénico of various plant extracts compared with the activity of volatile N-nitrosamines in food. The investigation has been addressed in four phases: 1, - optimized method mutagenicity Ames S.typhimurium TA100 to estimate the mutagenic activity of the volatile N-nitrosamines, N-nitrosodimethylamine (NDMA), N-Nitrosopyrrolidine (NPYR) N-nitrosopiperidina (NPIP) and N-nitrosodibutilamina (NDBA). 2-We studied the mutagenic activity of extracts from various vegetable, fruit and liquorice root method Ames and the microsomal enzyme complex mammalian S9 for metabolic activation. 3-We evaluated the potential quimiopreventivo face of volatile N-nitrosamines plant extracts with no mutagenic activity. 4-It was felt the antioxidant capacity, reducing power and secuentrante peroxides of plant extracts with different activity antimutagénica face volatile N-nitrosamines. Statistical analysis of the data obtained has helped connect the ability of plant extracts to inhibit the mutagenicity induced volatile N-nitrosamines and its protective effect against oxidative processes. Overall, the work has provided Mr Youssef Ikklen extensive training and the results have led to the selection of various plant extracts, for its high potential quimiopreventivo, for further investigations.

Author: DÍAZ-REGAÑÓN VILCHES JAZMÍN.
Year: 2005.
University: COMPLUTENSE DE MADRID [www.ucm.es].
Place of defense: FACULTAD DE MEDICINA.
Place of preparation: FACULTAD DE MEDICINA.

Summary: The emergence, development and spread of resistance to antimicrobial agents is an important problem in the treatment of various infectious diseases and therefore is a need for alternatives to achieve the eradication of microorganisms along with the decline in secondary effects of antibiotic therapy. The use of probiotics in infectious disease is a very topical issue and with a growing interest in recent years. They have been used in Helicobacter pylori infection and treatment alone or associated with antimicrobial drugs, or to prevent the occurrence of adverse effects. Lately has also been beneficial effect of certain microorganisms not considered probiotics against infection by H. pylori may join probiotics "classics" as an alternative to conventional antibiotic therapy. In our study we studied the antibiotic sensitivity of 118 strains of H. pylori in gastric biopsies from patients adults and children, to you first-line antibiotics amoxicillin, clarithromycin, metronidazole and tetracycline, by agar diffusion per disk or test, from 2002 until 2005. It was also selected 15 microorganisms probiotics and 18 not probiotics and clashed with 46 strains of H. pylori by the methods of the groove and drop, to see the in vitro activity of these microorganisms on H. pylori. We also carried out curves and death, we studied the activity ureásica of H. pylori. All strains studied were susceptible to amoxicillin and tetracycline, while the overall resistance to metronidazole was 55% to 60% and clarithromycin. There was a significant increase in resistance to antibiotics last two both in children and adults, but it seems that the trend is stable. The rate multiresistencia was 32%. We found 5 probiotics (2 strains of Lactobacillus spp. Bacillus spp. E faecium and S.cerevisae) and 14 microorganisms not probiotics can inhibit the growth of one or more isolates of H. pylori. Specifically, a strain of S.auricularis and two strains of S.epidermidis inhibited the growth of all isolates of H. pylori to those who were at loggerheads. The microorganism full-2 strains of Staphylococcus studied appears to be responsible for the growth inhibition of H. pylori and, after centrifugation, filtration and lyophilization, not replicated this effect. The activity ureásica of H. pylori decreased between 22% and 99% after the incubation of the bacteria with different probiotic microorganisms and not probiotics. The effect of probiotics and probiotic microorganisms not appear to be independent of the pathogenicity of H. pylori, and that the microorganisms were able to inhibit the growth of one or more isolates of H. pylori, and that the microorganisms were able to inhibit growth one or more isolates of H. pylori with different characteristics of pathogenic and antibiotic sensitivity.

Author: GUNDIN RIVAS GEMA.
Year: 2005.
University: COMPLUTENSE DE MADRID [www.ucm.es].
Place of defense: UNIVERSIDAD COMPLUTENSE DE MADRID.
Place of preparation: UNIVERSIDAD COMPLUTENSE DE MADRID.

Summary: It is defined as normal flora those microorganisms that appear on the body or inside him, in healthy individuals. The normal flora has an important role as a defensive barrier to prevent colonization by pathogenic bacteria and make a constant antigenic stimulation of defense mechanisms. At present most of the infections we see are caused by bacteria of the normal flora. Being aware necessary to prevent secondary infections to tissue damage, identify the source of infection and the meaning of the clinical isolates, as well as for sampling. Well, we drew both making mistakes in the handling of the samples, appearing in growing microorganisms polluting and not members of the flora. In the oropharynx the normal flora is composed of streptococcus viridans group, corinebacterias, Moraxella catarrhalís and Haemophilus as bacteria more frequent. It may appear in a small number Candida Albicans. This flora is replaced by gram-negative bacilli within a few hours of admission to a hospital as various studies have shown. In surgery for head and neck cancer, a major postoperative complications of the surgical wound infection, with all the associated pathology that. The use of antibiotic prophylaxis to minimize pollution decreases perioperative Post-surgery infection. Why are infected despite prophylaxis is unknown although several scenarios being considered as a state of immunosuppression by the tumor, the nutritional deficit that sometimes associated patient, the stress is a very aggressive intervention sometimes. In our study Post-surgery infection figures are lower due to the use of treatment in patients at risk compared to profilaxix antibiotic as advocating certain authors. Ultimately, the study of changes in the flora oropharyngeal cancer patients in head and neck and its relationship to postoperative complications in the opening line of an important work in investigating the possible causes of surgical wound infection in patients oncology. Because no study linking the impact of changes in the flora oropharyngeal with post-surgical complications.

Author: ZAMORA BERNA JORGE.
Year: 2005.
University: COMPLUTENSE DE MADRID [www.ucm.es].
Place of defense: FACULTAD DE MEDICINA.
Place of preparation: HOSPITAL UNIVERSITARIO 12 DE OCTUBRE Y FACULTAD DE MEDICINA.

Summary: It has been discussed for the first time the cytochrome b mitochondrial gene in the species American Carduelis dominicensis, Carduelis atríceps and Carduelis pirus perplexus. Along with the Carduelis pinus pinus, these species are defined as a monophyletic group closely related species Eurasian C.spinus. The cytochrome b mitochondrial gene has been sequenced in these species and studying phylogenetically along with the majority of species Carduelis worldwide. The lineages that have led to the current Carduelis species studied appear to have divergido initially in the Pliocene. The Pleistocene also have played an important role in the diversification of existing species C.pinus pinus, C.pinus perplexus and C.atríceps. The kind of the Antilles C.dominicensis shows an origin in the Pliocene within this group lúganos Americans. It has been found in the geographical structure of the individual sequences species C.pinus pinus belonging to different populations located in extreme points of its range. The lack of structure filogeofránfica found in the sequences C.pinus pinus could be the result of an expansion from a bottleneck from a glacial refuge. The species C.atriceps and C.pinus seem to be the last to appear in North America. The pattern filogeográfico of Carduelis dominicensis is still unclear, and their morphology is atypical within delos members of his radiation, probably due to lack of ancestors and missing, or convergent evolution as a result of its isolation in the mountainous region of the Spanish island . The taxonomic status of the species C.pinus pinus C.pinus perplexus and C.atriceps, baado character fenotílicos not reflected in the filogenias AND mitocondnrial, probably because of a recent origin of these species. The gene sequences of MHC class I to several species of American Carduelis not appear to be subject to selection in the region of peptide binding. Thus, the evolution of these molecules could respond to needs of very restricted antigen presentation.

Author: CARRASCO SIERRA MARIA ANGELES.
Year: 2005.
University: MÁLAGA [www.uma.es].
Place of defense: FACULTAD DE CIENCIAS.
Place of preparation: FACULTAD DE CIENCIAS.

Summary: The dissertation deals with the structural characterization and important aspects of the ecophysiology of microbial mats dominated by the kind Microcoleus chthnoplastes. It has been determined the specific composition of these rugs, reflecting a patent dominance of the species M.chthonoplastes. The techniques of optical and electronic microscopy have yielded important information about the differences in the structure of the mats in depth, as well as between morphotypes of sun and shade, reflecting adjustments to ultrastructural level (abundance of trichomes, filaments and the chloroplasts structures like tilacoides) of the species cianobacteriana conditions of high and low irradiance. It has been determined response to the conditions lumínicas (qualitative and quantitative) of the two morphotypes, characterizing both habitats and the process of capturing light. Moreover, the ultrastructure have been associated with the response of photosynthetic apparatus, both pigment as transport electrons. We discuss, based on these results, the strategies of the mats to the different conditions of irradiance, as well as the high degree of adaptation to changes give the same. This plasticity is presented as a key factor to explain the ecological diversity and its wide distribution in harsh environments. Another part, have been characterized mechanisms incorporating carbon in the species, using several inhibitors. Finally, it discusses the important role of bacterial mats in relation to the cycle of nutrients in the sediment of the marshes, with a recycling of organic matter in the interior of the same.

Author: MARTOS PÉREZ FRANCISCO.
Year: 2005.
University: MÁLAGA [www.uma.es].
Place of defense: FACULTAD DE MEDICINA.
Place of preparation: FACULTAD DE MEDICINA.

Summary: The recurrence of human brucellosis affecting 5-10% of patients treated with the existing regime more effective (doxycycline 6 weeks with streptomycin the first 2-3 weeks). The use of other regimes produces higher rates of relapse. There is little evidence of contributory factors for recurrence of brucellosis. The only two published studies have excessive rate of recurrence due to the use of experimental treatments. In addition, do not consider therapeutic compliance. The objective of this study was to identify the factors that predispose to relapse in 857 adult patients diagnosed with brucellosis between 1982 and 2001 in the Unit for Infectious Diseases Hospital Carlos Haya (Malaga, Spain). It also studied: clinical characteristics of relapses, profitability of microbiological methods, and analytical parameters in its diagnosis. The 83% of patients was treated with the therapeutic regimen for maximum effectiveness, and the relapse rate was very low (4.5%). No symptom or finding exploratory predicted relapse. The therapeutic failure, the presence in the initial episode of elevated alfa-2-globulina serum, thrombocytopenia, or erythrocyte sedimentation rate (ESR) less than 30 mm. They increased relapse. The clinical presentation delas recurrences was more silent that the initial pictures, but its rate of complications similar. Blood cultures tracking are not efficient for the diagnosis of recurrence. The profitability of serology is low. The alterations in laboratory parameters help in the diagnosis. High levels of transaminase, gammaglutamiltransferasas, VGS, Proteína-C-reactiva or adenosina-deaminasa (ADA), supported the diagnosis of relapse. The serum level of the ADA was the most useful parameter. A level of ADA greater than 18 IU / L PCR greater than 10 mg / L achieved a sensitivity of 66.7% and a specialty of 89.7% in the diagnosis of relapse.

Author: PONS XIMÉNEZ JOSÉ IGNACIO.
Year: 2005.
University: BARCELONA [www.ub.es].
Place of defense: FACULTAD DE BIOLOGÍA.
Place of preparation: FACULTAD DE BIOLOGÍA.

Summary: In the adaptation of bacteria to environmental changes play an important role proteins associated with nucleoide. These proteins have a dual function: the structuring of nucleoide bacterial and other processes related to DNA as is the regulation of gene expression. One of the proteins associated with nucleoide best is characterized protein H-NS, which are widely distributed in bacteria G (-). One of the characteristics of H-NS is its ability to form dimers with members of the family of proteins Hha / YmoA, thus forming complexes repressors involved in the regulation of certain operons, as in the case of operon hly E. coli. In this work, and in collaboration with the group of NMR biomolecules led by Dr. Miquel Pons, has been made one laughs study on the structural protein Hha and their interaction with H-NS, which has shown that, even without some of the waste aminoacídicos more improtantes in the interaction of Hha with H-NS, the cysteine at position 18 plays an important role in the equilibrium conformations of Hha when intercciona with H-NS. The replacement of this by a cysteine isoleucine leads to a protein Hha mutant unable to complement the mutation hha, and that leads to a reduction in the growth rate of E.coli in conditions of low osmolarity. This effect under conditions of low osmolarity in E.coli could come explained by the increased resistance to the ionic strength of fear of the interaction of this protein Hha mutant with protein H-NS, which could come explained by the increased resistance to ionic strength from the middle of the interaction of this protein Hha mutant with protein H-NS, which could lead to deregulation of some gene / is essential in terms of low osmolarity. A second part of this Doctoral Thesis is dedicated to gene hns of Y.enteroolítica. Previous studies carried out by our research group showed the essentiality of the gene hns in this bacterium because it is only possible to obtain mutants hns in Y.enterocolítica in the presence of a functional member of the family of proteins H-NS. In this thesis, we focus on the system used to obtain a mutant hns in the presence of the protein StpA, protein paráloga to H-NS in E.coli. The results helped verify that the presence of StpA in Y.enterocolitica cause drastic changes in their pattern of protein expression and highlighted the importance of proteins H-NS or YmoA in this bacterium. The protein YmoA is officially approves a protein Hha of E.coli and it is also able to interact with H-NS. The analysis of these results has shown, on the one hand, the presence of StpA in Y.enterocolitica simulates an increase in non-physiological levels of protein HS, on the other hand, the importance not only of the presence of proteins H-NS and Ymo in Y.enterocolitica, but also the importance of their relative levels, and that an increase in levels of H-NS or decrease in the YmoA cause a drastic alloy in the pattern of protein expression of Y. enterocolítica.

Author: MARTIN GARCIA REBECA Ma..
Year: 2005.
University: SALAMANCA [www.usal.es].
Place of defense: FACULTAD DE BIOLOGIA.
Place of preparation: DEPARTAMENTO MICROBIOLOGIA Y GENETICA / INSTITUTO DE MICROBIOLOGIA BIOQUIMICA.

Summary: The protein Chs2p of the fission yeast Schizosaccharomyces pombe is an integral membrane protein with similarity to enzymes Quitín Sintasas (conducting the synthesis of chitin) of other fungi and yeasts. In particular presents similarity with protein Chs2 Saccharomyces cerevisiae, has been implicated in the synthesis of chitin the septum primary cell is formed between mother and daughter during cytokinesis. Despite lacking catalytic activity Quitín Sintasa, protein Chs2p of S.pombe seems to exert a structural role in cytokinesis of this body. The protein Chs2p is located in the zone of cell division, forming a ring that is contracted preceding synthesis septum. The location depends on the overall system of polarized secretion, the existence of a ring of actomiosina functional and signal provided by the INS complex, which promotes the onset of septación. The gene chs2 + is functionally connected with various components of the contractile ring with which introduced gene interaction. One of these components is Myo3p, one of the miosinas type II in the contractile ring of this yeast. In addition, Chs2p, an integral membrane protein, introduced physical interaction with this protein, Myo3p, it is an anchor point of contractile ring to the membrane. Finally, Chs2p involved in maintaining the integrity of the ring actomiosina during the final stages of the process of contraction of the same, because of deletion mutant gene chs2 + presents partial fragmentation of the ring during contraction.

Author: AMUTIO DIEZ ELENA.
Year: 2005.
University: PAÍS VASCO [www.ehu.es].
Place of defense: FACULTAD DE MEDICINA Y ODONTOLOGÍA.
Place of preparation: FACULTAD DE MEDICINA Y ODONTOLOGÍA.

Summary: Patients hematólogicos neutropenic present a special susceptibility of invasive fungal infections, particularly prevalent in today and whose diagnosis is based on techniques micribológicas conventional is not always sufficiently early to avoid the ominous prognosis of these infections in this population of patients. We have studied 133 patients with hematologic neutropenic consecutive biweekly serological determinations. After classifying patients according to a model of risk groups, has been made the determination of antibodies to the mycelial phase of Candida spp.mediante a technique developed by our group, to distinguish between colonization and invasive candidiasis and their applicability in terms of risk factors associated with neutropenia. Moreover, it has selected a group of 54 patients in all risk groups, which has given periodically galactomanano Aspergillus spp.en serum through technical Platelia ® Aspergillus, with the aim to assess the diagnostic and his precocity utility depending on the risk groups in neutropenic patients.

Author: FERNÁNDEZ MARTIN MARIA EULALIA.
Year: 2005.
University: COMPLUTENSE DE MADRID [www.ucm.es].
Place of defense: FACULTAD DE MEDICINA.
Place of preparation: FACULTAD DE MEDICINA.

Summary: Our objective was to study the two populations Haemophilus influenzae, two periods, one before and another after wing introduction of Hib vaccine in our country. The strains ers overwhelmingly H. Influenzae not capsuladas, being a common pathogen in adult and geriatric. The predominant clinical manifestations were pneumonia and exacerbations of COPD, but also occasionally produced infections inversivas. The study consisted of microbiological tests for identification, sensitivity to various antibiotics, the study of the mechanisms of resistance by PCR and identification of the genes responsible for synthesis beta-lactamase, which is the main mechanism of resistance to beta-lactámicos.

Author: MUÑOZ FONTELA CÉSAR.
Year: 2005.
University: COMPLUTENSE DE MADRID [www.ucm.es].
Place of defense: FACULTAD DE FARMACIA.
Place of preparation: DPTO. MICROBIOLOGÍA II. FACULTAD DE FARMACIA.

Summary: The virus of KS (KSHV/HHV-8) is the last gamma-herpesvirus discovered so far. KSHV is the etiologic agent responsible for the disease proliferativas endothelial cells Kaposi's sarcoma, or B cells, as Castleman's disease or primary effusion lymphoma. The protein LANA2 is expressed exclusively in B cells infected with the virus, and has been shown to have activity anti-apoptótica by inhibition of apoptosis-dependent p53 or PKR. In this paper, we have deepened oncogénica activity of the protein LANA2, and we have shown that its subcellular localization is dependent on the presence of a nuclear localization signal, and a nuclear export signal, and that the functionality of these signals is essential to the activity of the protein. Furthermore, we have shown that LANA2 interacts with the family of protein retinobastoma through a consensus binding domain (LxCxE), and that the interaction of LANA2 with these proteins plays an important role in transforming activity of the protein. Also in this paper we have described the importance of LANA2 the survival of B-cells infected with KSVH and have described the interaction with the family of protein 14-3-3, and how this affects union control of the cell cycle of cells infected. Finally, in this thesis describes the antiviral activity of two important tumor suppressor, such as p53 and ARF, establishing a new connection between antiviral response karma inhibition in tumor cells.

Author: ALCAZAR FUOLI LAURA.
Year: 2005.
University: COMPLUTENSE DE MADRID [www.ucm.es].
Place of defense: FACULTAD DE CIENCIAS BIOLÓGICAS.
Place of preparation: FACULTAD CIENCIAS BIOLÓGICAS, UNIVERSIDAD COMPLUTENSE DE MADRID.

Summary: The research group has described two genes Aspergillus fumigatus denominated cyp51A and cyp51B encoding for 14-alfa sterol demtilasa, target enzyme of azoles. Mutations in some isolated strains of Aspergillus fumigatus resistant to azoles has been described as the cause of his cross-resistance to azole in these mutant strains. Continued to this line of research, in the search for mechanisms of resistance to antifungal agents, has been studied by other mechanisms of resistance that might explain phenotypes of resistance strains A.fumigatus not characterized. A well-defined mechanism, primarily in Sacharomyeces cersisiae and Candida albicans, is a decline, absence or deficiency in the enzyme activity of C-5 sterol desaturase. This enzyme acts on the route of synthesis of ergosterol and encoded by this gene ERg3. At work submitted has been carried out identification and characterization of three genes A.fumigatus (erg3A, erg3B and erg3C) encoding enzymes possible C-5 sterol desaturasas (Erg3A, Erg3B and Erg3C). It has been found that the three genes have a single copy in the genome of A.fumigatus, and that all three are expressed in normal growth. It has conducted a study of functional enzymes C-5 sterol desaturasas of A.fumigatus by creating strains defectivas in genes erg3A, erg3B and ergC. In a manner that has studied the feasibility of the mutant strains, its possible involvement in the resistance to azole and anfoterciina By his involvement in ergosterol biosynthesis in A.fumigatus. On the other hand, the existence in A.fumigatus two enzymes Cyp51 and three enzymes C-5 sterol desaturasas led to rethink the classical pathway of synthesis of ergoseterol described in S.cervisiae. This paper describes for the first time, the route of synthesis of ergosterol in A.fumigatus.

Author: DÍAZ SAN SEGUNDO FAYNA CLAUDIA.
Year: 2005.
University: COMPLUTENSE DE MADRID [www.ucm.es].
Place of defense: FACULTAD DE VETERINARIA.
Place of preparation: FACULTAD DE VETERINARIA, UCM.

Summary: The encephalopathies espogiformes transmissible are a large group of diseases neurodegnerativas that can affect both men and animals and are characterized for the presence of deposits from one form to berrante of the cellular prion protein (PrPC), called resistant prion protein (PrPres) . The latest outbreak of one of these diseases was Bovine Spongiform Encephalopathy (BSE) began in Britain in the late eighties and spread to all EU countries, including Spain. This disease affects cattle, but it has shown its transmission to other animal species as the sheep and men. Understanding the role of the barrier is crucial for species to predict the possible spread of this disease to other animal species to transform part of the food chain. Spain is the second largest producer of pigs in the European Union. The importance of the livestock sector in Spain pork, and especially the kind of intensive, require the approach of a possible transmission of BSE to the pig species, and this species has traditionally been fed with feed consisting of meat up its ban in the year 1996. Therefore this paper studies the transmission of BSE and Scarpie in pigs and in transgenic mice expressing the gene dela PrPC swine using different seeds of EB and Scarpie from different sources. In addition, it discusses the possible role of the distribution of the PrPC in the central nervous system (CNS) in the species barrier. Finally an analysis of the possible implications of the immune system in the pathogenesis of these diseases and their possible implications of the immune system in the pathogenesis of these diseases and their possible role in the species barrier.

Author: ARACIL GARCÍA M. BELÉN.
Year: 2005.
University: COMPLUTENSE DE MADRID [www.ucm.es].
Place of defense: FACULTAD DE MEDICINA.
Place of preparation: FACULTAD DE MEDICINA, UNVIERSIDAD COMPLUTENSE DE MADRID.

Summary: In the mid-80's, in Spain, began to describe high rates of antibiotic resistance in H. influenzae, especially in H. influenzae serotype B (Hib). The mass vaccination of the child population was responsible for the changes in the natural evolution and epidemiology of invasive Hib disease. The vaccine is highly effective, cautioned largest 90% of cases of childhood meningitis and sepsis, but later studies showed that vaccine failures that occurred in the United Kingdom also reached epidemic proportions. Against this background, it was necessary to make a study on the epidemiology and clinical significance of Haemophilus influenzae in the days after vaccination. And as a result of that we might conclude that the increased frequency of illness invasive Haemophilus influenzae currently in Spain, occurs in the extreme ages of life, which are risk factors in about 75% of cases. Nearly 3 / 4 of the isolates caused disease invasive Haemophilus influenzae are not capped and the rest are capsuladas of serotypes b, e and f. There is no evidence that infections caused by Haemophilus influenzae, no b, e and f especially, as well as strains not capsuladas, have increased after vaccination campaigns. Besides causing especially opportunistic infections in adults with significant risk factors predisposing, and only occasionally affects children. The strains of antibiotic resistance rates high despite a decline in the use Community as chloramphenicol, tetracycline and co-trimoxazole. The most virulent strains capsuladas and are significantly more resistant that are capsuladas. The acquisition of plasmids conjugativos (high pm) is common both in resistant strains of Haemophilus influenzae capsuladas with capsuladas; there is a strong association between single and multiple resistance to these antibiótiocs and the presence of plasmids. Moreover, the isolates by serotypes e and f, show high rates of resistance, especially ampicillin and cotrimoxazole and multiple resistance. The study of the molecular epidemiology of serotypes e and f, demonstrates the spread of a very predominant clone of each of the two serotypes regardless of origin or geographical clinical and antibiotic resistance of the strains. In Spain, most cases of pediatric vaccine failures of the conjugate vaccine against Hib are a consequence of the inability of the host to develop protective antibody and not the calving of new genotypes of the microorganism beyond the action of the vaccine. Also in the UK, the significant and rapid increase in vaccine failures, it is due to the same genotype circulasen prior to the widespread introduction of the vaccine. The vaccination does not appear to have changed the population structure Hib. The resistance to trimethoprim in Spanish strains of Haemophilus influenzae is nature and is due to chromosomal gene folA. The resistance to ampicillin, chloramphenicol, tetracycline and sulfamethoxazole is nature plasmídica and is due to genes tem1, catII, tetB and sul2 respectively, regardless of their clinical origin, geographic origin and capsule production or not.