ANTIBIOTICS

Author: OTEO IGLESIAS JESUS.
Year: 2004.
University: COMPLUTENSE DE MADRID [www.ucm.es].
Place of defense: FACULTAD DE MEDICINA.
Place of preparation: CENTRO NACIONAL DE MICROBIOLOGIA.

Summary: Resistance to antibiotics in some of the princiaples pathogenic bacteria in humans is a major problem of public health recognized throughout the world. Spain is one of the Western countries most affected by this problem. The European Union (EU) established in 1998 the project "European Antimicrobial Resistance Surveillance System for monitoring antibiotic resistance in isolates of blood and cerebrospinal fluid of Streptococcus pneumoniae, Staphylococcus aureus, Escherichia coli and enterococci in Europe. Spain participates in the network European official since 2000, providing information strains aisladoas by a group of 38 hospitals (average annual share), representative form distributed throughout Spain, which provide coverage to approximately 11,000,000 people (28 % of the Spanish population). The consumption of antibiotics is the main factor that determines the emergence of resistance. In Europe, consumption of antibiotics is subject to monitoring by the European Surveillance of Antimicrobial Consumption. " This thesis analyzes the data obtained by antibiotic resistance network EARRSS-España between 2001-2003, their profiles and phenotypic changes over time. In addition, it performs a estuido the correlation between consumption and resistance to antibiotics, and a comparative study of antibiotic resistance in the various European countries.

Author: GONZÁLEZ CABEZA JOSE GUILLERMO.
Year: 2004.
University: AUTÓNOMA DE BARCELONA [www.uab.es].
Place of preparation: ESCUELA DE POSTGRADO.

Summary: Given the clinical significance of quinolones in the control of infectious diseases and possible implications of the fact that these molecules are mutagenic agents in bacteriasl, this study has focused on deepening the mechanisms of mutagenesis, using ciprofloxacin as molecule model, and determine the mutagenic potential of quinolones in current clinical use. As regards the mechanisms of mutagenesis, it has been shown that for ciprofloxacin - induced mutagenesis, it is required that the bacteria have a system of nucleotide excision repair (NER) functional ruled that the operon moa, the cula encodes genes molybdenum cofactor biosynthesis have any role in that mutagenesis. These results corroborate previous studies, which suggested the involvement of the NER in that mutagenesis system, and indicate that probably other genes deleccionados in strains test S.enterica Typhimurium TA104 and TA2659 than uvrB mutation, should not have a major role in quinolones mediated mutagenesis. Moreover, it has been shown that cicprofloxacina can generate any reactive oxygen species, probably the superoxide anion (O2) and / or singlet oxygen producing oxidative damage, which should not be primarily injury 8-oxoG. Taken together, these results indicate that quinolones should produce different types of lesions in DNA from the bacterial cells. Thus, the interaction of the molecule quinolone with complex DNA-DNA girasa should generate a kind of distorisión similar to a link intercatenario, resulting in an injury premutagénica. Such an injury can be processed by the system NER and become a lesion on the mutagenic DNA polymerase an act which seeks to error, similar to MucAB and introduciríra a mutation. This mutagenesis mechanism should be common to this type of molecules. Moreover, the results of mutants soxRS indicate that this family of compounds also introduced oxidative injury, which should be more relevant in those molecules described as fototóxicas as clinafloxacina, lomefloxacina and others. number of revertant in both test systems. The mutagenic potential of each quinolone must be related to its molecular structure, permeability of the accumulation of bacteria and quinolones. It relaicona low capacity of mutagenesis of the moxifloxacina in both trials with the presence of a methoxy group at position C-8, while ciprofloxacin is identified as a molecule highly mutagenic in E.coli WP2/pKM101 and low activity in S.enterica Serov. Typhimurium. It should be noted that mutagenesis study is manifested in doses of quinolones below the WCC each molecule in the strains tested. In response to these results is discussed the possible implications of the statement of problaciones of pathogens at low doses of quinolones and intends such as calves study for the development of new molecules of this family of antibiotics, which should provide better antibacterial activity with a low capacity to introduce mutations.

Author: VIZCAINO GONZALEZ JUAN ANTONIO.
Year: 2004.
University: SALAMANCA [www.usal.es].
Place of defense: FACULTAD DE FARMACIA.
Place of preparation: UNIVERSIDAD DE SALAMANCA.

Summary: This Doctoral Thesis contains four separate chapters. I Study of antibiotic activity of Trichoderma strains. It conducted a study of the antibiotic activity of 24 strains of different species of Trichoderma on a panel of 20 microorganisms target. There was a large variation between the activities detected, but there are no clear correlation between a certain kind of Trichoderma and pattern of producing antibiotics. II. Identifying peptaiboles, cloning and characterization of two peptide sintetasas T. Harzianum. First, it identified peptaiboles producing different species of Trichoderma. Then, using different strategies, we performed partial cloning of genes salps1 and salps2 in strain T. Harzianum CECT 2413, which codifies each peptide sintetasas. Salps1 seems to be a pseudogen. Through a comprehensive analysis of the sequence, makes assumptions about the potential role of these genes. III. Cloning and characterization of gene ThPTR2 T. Harzianum. Using a strategy based on the generation of ESTs was identified, clonó and characterized the gene ThPTR2 of the strain T. Harzianum CECT 2413, which encodes a transporter oligopéptidos the family PTR. We performed both homologous and heterologous an overexpression of the gene and testing activity confirmed the planned activity. It is the first carrier of this type has been studied in filamentous fungi. IV. Cloning and characterization of gene chit101 T. Atroviride. Using the same strategy earlier identified clonó and characterized the gene chit101 of the strain T. Atroviride T11. Chit101 encodes the first quitinasa type "plant" studied in Trichoderma. We performed counterpart overexpression of the gene and conducted tests activity quitinasa who confirmed this activity.

Author: MILLÁN LAPLANA LETICIA.
Year: 2004.
University: ZARAGOZA [www.unizar.es].
Place of defense: FACULTAD DE MEDICINA.
Place of preparation: FACULTAD DE MEDICINA.

Summary: The overall objective of this study was to analyze the state of the molecular epidemiology of the genetic determinants of resistance to antibiotics in MLS strains of Staphylococcus aureus and species estafilocococs coagulasa-negativos (SNA) isolated in the service of Microbiology University Teaching Hospital " Lozano Blesa "Zaragoza, as well as its structure and regulation, and completing a study of its spread. Likewise, based on the phenotypes of resistance to various antibiotics, trying to characterize some of the genes responsible for these resistors and dissemination. In strains of staphylococci resistant to erythromycin studied, the prevailing phenotype MLSB establishing phenotypes on the inducible and MS. There was a high rate of multi strains, showing the efficient dissemination of resistance genes, being higher in SNA in S. Aureus, which suggests the performance of the first reservoir of these genes. That multi-resistencia not affected, however, vancomycin and linezolid, which showed an excellent in vitro activity. There was a good correlation between the determination of resistance to oxacillin by agar dilution and detection of mecA, with large discrepancies with the disk diffusion technique, which leads to recommend the use of various methods to simultaneously detect such resistance. The gene erm (C) prevailed regarding erm (A) both in S. Aureus as SNA not detected mef (A) (A) or erm erm subclass (TR) under any strain. There was an increase in the prevalence of erm (B) in clinical isolates of staphylococci, suggesting a horizontal spread of this gene from enterococci, pneumococci and / or staphylococci share ecological niche, and clonal propagation of staphylococcus carriers. There were several combinations of genes between them and erm msr (A), the latter prevail in SNA. Paradoxically, some of these isolates expressing only the second since the phenotype was MS. Hence, while the resistance phenotype shows genotype, it is necessary to study the determinants present given the possible combination of these. Similarly, knowledge of the genotype is necessary to study the phenotypic expression. Gross deletions were found in 58 and 107 bp in the region regulator erm (C), and Gross deletions of 10 (described for the first time) and 121 bp in the erm (A) explaining the constitutive expression of the two genes. The genes were detected aac (6 ') / aph (2''), prev (4') -Ia, aph (3 ') -IIIa and ant (6) as responsible for resistance to aminoglycosides, while the non-detection some of them suggested resistant strains in the presence of other mechanisms of resistance. It was confirmed in some strains of S. SNA aureus and the presence of ant (6) -sat4-aph (3 ') -IIIa forming a group (cluster) whose vector is Tn5405, demonstrating that there is already a gene for antibiotic never used in Spain: estreptotricina. The genes were detected tet (K) and tet (M) resistance to tetracycline. The presence of intTn in two S. Aureus carriers tet (M) suggested the presence of Tn916 or similar. It confirmed the presence of Tn554 in S. Erm aureus carriers (A) and the transfer conjugativa of erm (A), (B) erm, erm (C), msr (A), prev (4 ') -Ia, aph (3') -IIIa and aac ( 6 ') / aph (2''). The location of many elements not conjugativos suggests that the transfer is mediated by transposons and / or plasmids conjugativos to mobilize. We identified 6 types of structural SCCmec in S. Aureus and 16 in SNA, of whom 14 are described for the first time. The characterization by PFGE showed great uniformity among strains of S. Aureus and S. Haemolyticus, indicating a clonal spread of resistant strains, contrasting with the great heterogeneity of S. Epidermidis and S. Hominis, which confirms the diseminac 8 ion hori 29d zontal of resistance genes.

Author: BRIÑAS HERCE LAURA.
Year: 2005.
University: LA RIOJA [www.unirioja.es].
Place of defense: UNIVERSIDAD DE LA RIOJA.
Place of preparation: UNIVERSIDAD DE LA RIOJA.

Summary: We have characterized the type and variant genes coding for enzymes beta-lactamasas in a number of strains of E. Diners coli and clinics in animal and human strains isolated from food samples at different time periods between the years 1997 and 2003. It has studied the temporal evolution of the beta-lactamasas of spread spectrum (BLEEs), the relationship between clonal strains producing BLEEs, the environment of the genes coding for BLEEs the family CTX-M and the presence of integrones in strains of these genes. Some strains of E. Coli study has identified three mechanisms responsible for resistance to broad-spectrum cephalosporin: i) hiperproducción of Beta-lactamase chromosome AmpC, for the presence of mutations at positions -42 or -32 of the promoter gene ii) Production the cefalosporinasa plasmídica CMY-2, and iii) the production BLEEs, chiefly family CTX-M. It has detected an increase over time the number of strains of E. Coli, diners and clinics animal producing BLEEs and greater diversity of these BLEEs. It has also been observed an increase in BLEEs the family CTX-M, which were identified CTX-M-14 as majority CTX-M-9, CTX-M-1 and CTX-M-32. There has been a great diversity among clonal strains of E. Coli, animal or human, producing BLEEs or cefalosporinasas plasmídicas suggesting that the spread of genes from these beta-lactamasas may be due to a horizontal transfer, and not the spread of a clone. It has been observed that none of the strains of E. Carrying studied coli gene coding for BLEEs or the cefalosporinasa plasmídica CMY-2, showed mutations at positions -42 or -32 promoter ampC, related hiperproducción of Beta-lactamase chromosome. The gene Beta-lactamase CTX-M-9 appears in all cases included in the integrón In60, while there have been changes in the organization and composition of such integrón. We have detected changes in the variable region and has identified the sequence of the gene insertion IS1 behind. On the other hand most of the genes of the b-lactamasa CTX-M-14 were flanked by sequences insertion ISEcp1 and IS903, though, in three strains identified this gene included in the integrón In60. The genes of beta-lactamasas CTX-M-1 and CTX-M-32 had the same genetic environment, which detected the sequence ISEcp1 front and orf1 behind the gene. The 75% of the strains containing genes beta-lactamasas type CTX-M, had integrones type 1 or 2. Among the integrones Type 1 was found six different combinations of gene cassette while among type 2 only identified a unique combination of gene cassette. Most of these integrones contains genes that confer resistance to antibiotics is not beta-lactámicos as trimethoprim, streptomycin or sulphonamides. The 28% of the strains with type CTX-M genes of the gene were included in the integrón, although not as any gene cassette. One of the strains containing the gene Beta-lactamase CTX-M-32 presented an in 8 tegrón d 4ba and type 1 that contained a gene cassette is not related to antibiotic resistance, but with features of signal transduction. The intestinal microbiota of healthy animals is a reservoir of genes for antibiotic resistance beta-lactámicos, these resistance genes could be transferred to other microorganisms in the intestinal microbiota and pathogenic microorganisms. The use of antibiotics is not beta-lactámicos as trimethoprim, streptomycin or sulphonamides can be a factor in selecting bacteria E. With coli genes BLEEs type CTX-M.

Author: RODRÍGUEZ MARTÍNEZ JOSÉ MANUEL.
Year: 2005.
University: SEVILLA [www.us.es].
Place of defense: FACULTAD DE MEDICINA.
Place of preparation: FACULTAD DE BIOLOGÍA.

Summary: In 1998, was first described resistance to quinolones horizontally transmissible through a plasmid conjugativo. The spread horizontal mechanisms of resistance to fluoroquinolones opens the possibility of a rapid spread of resistance to these antibiotics, both in animal and human pathogens, and even more so with the extensive use made of them. The investigative work reflected in this Doctoral Thesis has yielded information on two fundamental aspects that surround this phenomenon: 1 - The spread of horizontal mechanisms of resistance to fluroquinolonas is an effective way for the rapid expansion of this resistance group of antimicrobials. 2 - The decrease in sensitivity to quinolones mediated gene qnr undertakes detecting resistance through automated systems and leads to therapeutic failure.

Author: FENOSA BERNADÓ ANNA.
Year: 2005.
University: BARCELONA [www.ub.es].
Place of defense: FACULTAD DE MEDICINA.
Place of preparation: FACULTAD DE FARMACIA, UNIVERSIDAD DE BARCELONA.

Summary: The main aim of the thesis was to study the mechanisms involved in resistance to fluoroquinolones in clinical isolates of the genus Klebsiella, focusing studies on the mechanisms of reflux. The mechanisms that confer resistance to the bacteria for a particular antibiotic can be different. From enzymatic inactivation of the antibiotic, changes in the tissues and mechanisms as the more general decline in membrane permeability and the expression of bombs reflux. The bombs reflux are translocasas which are located in the membrane citiplasmática capable of driving away from the bacteria a wide variety of substances through force protón-motriz therefore do not require the hydrolysis of ATP. In regard to the bombs reflux bacterial Gram negativs it has been found that in E.coli. The operon acrAB, encodes for a bomb reflux but not encode for any of outer membrane protein (OMP), has been described which is the protein TolC, serving as a channel of outer membrane. In the case of a system called Klebsiella reflux AcrAB com of the E.coli, and the studies revealed the presence of this bomb reflux in clinical isolates studied and his involvement in the resistance to fluoroquinolones through measures accumulation cicprofloxacina, antibiotic effects on growth curves and death. It is not known which protein is a channel of the outer membrane that is linked to the bomb reflux AcrAB in Klebsiella. The search for this protein associated with reflux pump was the main objective of this dissertation. It revealed the presence of the protein TolC in a clinical strain of Klebsiella oxytoca, which determined its sequence was compared with that of other entrobacterias getting a high percentatge of identitat, especially with the proteà ¯ na TolC E. aerogenes. Once known protein sequence TolC of K.oxytoca carried out a model approach to the structural protein TolC of K.oxytoca getting a structure very similar to that described in E. coli. The most notable difference was observed in chains that extend outward from the bacteria, these structures is responsible be receiving bacteriocins and fagos where TolC of K.oxytoca presented a lesser length. The study sensitivity colicinas was observed resistance colicina E1 of the strain clinic K.oxytoca, so the length of their smaller chains external amending its role com a receiver colicinas. Physiological studies on the protein TolC of K.oxytoca showed that this protein form transmembrane channels in bicapas lípidicas artificial with a roughly 80 pS conductance in LC1 1M and that presents a strong cationic selectivity.

Author: GALLARDO MONTILLA FRANCISCO.
Year: 2005.
University: BARCELONA [www.ub.es].
Place of defense: FACULTAT DE MEDICINA.
Place of preparation: FACULTAT DE FARMÀCIA - UNIVERSIDAD DE BARCELONA.

Summary: The objectives pursued by the conduct of this study were: 1-To analyze the evolution of resistance to antimicrobial agents in different clinical isolates of Salmonella, Campylobacter and Aeromonas and compare different levels of resistance to antimicrobial agents in clinical isolates from diarrhea our area goegráfica and traveler's diarrhea. 2, - study the molecular basis of the mechanisms of resistance to ampicillin, aminoglycosides, chloramphenicol, trimethoprim and quinolones in clinical isolates of Salmonella typhimurium. 3-To investigate the mechanisms of quinolone resistance in clinical isolates of Campylobacter jejuni and Aeromanas spp. The conclusions reached: 1-In recent years there has been a significant increase in levels of resistance to antibiotics used in clinical practice by Salmonella enterica serotype Typhimurium, Campylobacter spp., And Aeromonas spp. This increase is observed both in isolates from patients in our geographic area as those with traveler's diarrhea. 2-Increasing resistance ampicillina in Salmonella enterica serotype Typhimurium is conducted largely by synthesizing beta-lactamasas type TEM and CARB and to a lesser extent the b-lactamasas type OXA. 3 - The dihidrofolato reductase is the widely distributed in Salmonella enterica serotype Typhimurium and is the primary mechanism of resistance to trimethoprim in this microorganism. 4-In addition to the expression of chloramphenicol acetyl transferase, there must be another mechanism of resistance to chloramphenicol in Salmonella enterica serotype Typhimurium. 5-strains of Salmonella enterica serotype Typhimurium from the same clone have different antibiotic susceptibility which suggests a divergent trends associated with the acquisition of mobile genetic elements that contain determinants of resistance to antibiotics. 6-Aeromonas veronii biotype sober is the species of the genus Aeromonas most frequently found as a cause of traveler's diarrhea. 7, - The symptoms which define a enteritis by Aeromonas are watery diarrhea and persistent fever and abdominal pain. 8, gender-Campylobacter and Aeromonas there has been an increase in resistance to quinolones, attributed to the presence of mutations in the genes gyrA (in both species) and torque C (in Aeromonas). 9-spot alterations in the gene gyrA of campylobacter spp, leading to a significant increase in the securities of MIS quinolone unlike other microorganisms that need additional mutations in other genes such as the parC. 10 - The observed differences in the MIC quinolone Aeromonas on gender may be due to overexpression systems expulsion active antibiotic.

Author: AL WARAGLI NADA.
Year: 2005.
University: CÓRDOBA [www.uco.es].
Place of defense: FACULTAD DE MEDICINA.
Place of preparation: FACULTAD DE MEDICINA.

Summary: Today, from a clinical point of view, both typical and atypical mycobacteria produce serious pathological tables. In old diseases such as tuberculosis and other recent as mycobacterioses. Clinical manifestations are heavily dependent on the immune status of the person concerned. The mycobacterioses is one of the most frequent complications of AIDS, and tuberculosis is the only opportunistic infection in HIV patients with a remarkable ease of contagion. In fact, there has been an increase in the number of patients with tuberculosis, and there is a big problem of resistance, in a complicated multi-resistance. Hence the need to explore new approaches chemotherapy. The aim of this study therefore is to study the activity and the potential clinical efficacy of two new fluorquinolonas moxifloxacina levofloxacin and fourth-generation and third respectively. This determines the minimum inhibitory concentration by the computerized system ESP, and calculated the values of CMI90, CMI50, and the IRA (the ratio relative inhibition). In addition, it carries out a comparative study of the activity of these two drugs already used ciprofloxacin and ofloxacin in the treatment of Mycobacterial infections. The five species of mycobacteria interest clinical object of this study are: M.tuberculosis, M.bovis, M.avium, M.fortuitum and M.chelonae. The moxifloxacina have the best shows in vitro activity and increased clinical efficacy. In turn the levofloxacin shows to be more active than their D-isómero ofloxacin.

Author: VALVERDE ROMERO EMILIO DAVID.
Year: 2005.
University: SALAMANCA [www.usal.es].
Place of defense: FACULTAD DE MEDICINA.
Place of preparation: FACULTAD DE MEDICINA.

Summary: In the Microbiology Laboratory at the University Hospital of Salamanca, collected strains of E. Coli, K. Pneumoniae, K. Oxytoca and Salmonella enterica presenting a diminished sensitivity to third-generation cephalosporins and / or aztreonam and presenting positive evidence of synergism with clavulanic acid. We performed isoelectroenfoque for determining the isoelectric point of each betalactamasa and showed the ability to conjugation of the same strain from a donor to another recipient, by the method of filtration membrane. It amplified the corresponding genes coding for each type of BLEE or qnr, who were identified with the sequencing reaction. For epidemiological analysis of the strains, a RAPD. In cases where it does not discriminate between different strains carried out a PFGE. The strains obtained were distributed: Klebsiella pneumoniae (33 strains), Klebsiella oxytoca (4 strains), Escherichia coli (114 strains) and Salmonella enterica (5 strains). The 156 strains represent an overall incidence of 1.1%. Patterns found in BLEE strains were, in most cases, in a BLEE type CTX-My / or type VHS, alone or accompanied by an BLEE type TEM. As regards the type of BLEE, proved to be the most frequent CTX-M 14, followed by TEM-116, VHS-2, VHS-12, CTX-M 15, CTX-M 9. We describe the first in Spain producing strain of CTX-M 27 and the first that carries the gene qnr. How was observed with the increase in the rate BLEEs simultaneous produced by the increased strain CISG presenting it, and different values for different cephalosporins CIM depending on the type of BLEE produced. With regard to the molecular epidemiology of the isolates were found among a wide range clonal strains, with a limited homology between them, except for the strains of Salmonella producing CTX-M 9 and some strains of K. Pneumoniae producing SHV-2.

Author: ANTÓN FIDALGO NURIA.
Year: 2006.
University: LEÓN [www.unileon.es].
Place of defense: FACULTAD DE CIENCIAS BIOLÓGICAS Y AMBIENTALES.
Place of preparation: INSTITUTO BIOTECNOLOGÍA (INBIOTEC).

Summary: The pimaricin molecule represents a prototype of polienos glycosylated. It is produced by Streptomyces natalensis ATCC 27448 and is routinely used in the food industry to prevent contamination by mold in cheese and other foods is not sterile (cured meats, sausages, cold cuts, etc..), Also being implemented with great success in preventing fungal infections in ophthalmology, especially after cornea operations, and in the prevention and treatment of keratitis of the same origin. The pimaricin is a macrolide tetraeno with a ring macrocíclico (pimaricinolida) of 26 carbon atoms, including the closure of the link lactone -CO-O-. It marked the grouping gene responsible for the biosynthesis of this polieno (90 KB), which has found 13 modules poliquétido synthase enzyme distributed among five Giants (PIMS0 to PIMS4). Thirteen additional genes appear to govern the changes to the skeleton poliquétido formed by the five aforementioned enzymes, their secretion and regulation. This work focused on the search, cloning, sequencing and characterization of potential gene regulators biosynthesis pimaricin. The sequencing of the left edge of the gene cluster responsible for the synthesis of pimaricin revealed the presence of a gene pimR, a gene 3597 bp that encodes a protein regulator PimR of 1198 yy. PimR represents the archetype of a new class of regulators, which combine a regulatory domain of the biosynthesis of antibiotics from Streptomyces (SARPs) in the N-terminal section, a section homologous C-terminal to guanylate ciclasas (cyc) and regulators large-dependent ATP family LuxR (LAL). The inactivation of this protein makes the strain does not produce pimaricin, which makes PimR a positive regulator of the synthesis of pimaricin. After studies at transcriptional level, it became apparent that this protein acts declined nuyendo levels of transcription of all the genes in the cluster of gene pimaricin and blocking transcription of the gene pimE. PimE is a gene that encodes a functional cholesterol oxidase, which blocks the synthesis of inactivation pimaricin. Following the sequencing of the left side of the grouping gene biosynthesis of pimaricin identified a new gene, the gene pimM of 579 bp that encodes a protein PimM of 192 aa. PimM belongs to this group of regulators, presenting a PAS domain in its N-terminal end in the area and a C-terminal DNA-binding domain HTH type LuxR. The presence of a PAS domain within PimM suggests that this protein could respond as a sensor to changes in the energy levels in the cell (Ponting and Aravind, 1997), while the reason HTH informs us the ability to PimM to unite DNA (Stevens et al., 1994) and thus its possible involvement in the regulation of gene expression of pimaricin. Dysfunctional of PimM causing the lack of production pimaricin in Streptomyces natalensis. A study at all on transcriptional gene clustering of gene pimaricin was seen as PimM acts on pimS1-S0-DFGCB and reduces the transcription of pimJ-IKA-S2-S3-S4. Interestingly, there were no differences in the transcript regarding the strain in the genes pimR, pimE and pimH, suggesting that pimM and the first gene regulator for the biosynthesis of pimaricin pimR (Anton et al., 2004), operate independently each other. In conclusion, most likely these two regulators, PimR and PimM belong to different regulation circuits.

Author: GÓMEZ ESCRIBANO JUAN PABLO.
Year: 2006.
University: LEÓN [www.unileon.es].
Place of defense: FACULTAD DE CIENCIAS BIOLÓGICAS Y AMBIENTALES.
Place of preparation: FACULTAD DE CIENCIAS BIOLÓGICAS Y AMBIENTALES.

Summary: STREPTOMYCES CLAVULIGERUS IS A GREAT IMPORTANCE OF MICRO - ORGANISM BIOTECH BY BEING PRODUCER OF ANTIBIÓTICO BETA-LACTÁMICO CEFALOSPORINA CY OF INHIBIDOR OF BETA-LACTAMASAS ACID CLAVULÁNICO. THE "STRICT RESPONSE" IS AN ADAPTATION OF BACTERIAL MECHANISM THAT IS IN A COMPLEX SET OF CHANGES IN PHYSIOLOGICAL RESPONSES TO CONDITIONS OF SHORTAGE OF NUTRIENTS TO ALLOW THE SURVIVAL OF THE BASAL CELL WITH A METABOLISM. THE MAIN CARACTERÍSTICA IS A STRONG DESCENT OF THE SUMMARY OF RNA AFTER THE DEPRIVATION OF AMINO ACID. THE PRESENCE OF A ARNT DOWNLOADED AT THE SITE ACEPTOR OF RIBOSOMA ACTIVATE THE ENZIMA REAL, LINKED TO RIBOSOMA THROUGH THE PROTEÍNA L11 (CONSOLIDATED BY GEN RPLK). REAL CATALIZA THE TRANSFER OF A GROUP PIROFOSFORILO FROM THE ATP GROUP 3'-HIDROXILO OF OR GTP GDP, ORIGINANDO THE COMPOUND PPPGPP Or PPGPP RESPECTIVELY (REFERRED TO AS BOTH (P) PPGPP). MICRO IN THE GENDER STREPTOMYCES, THE ABILITY OF SUMMARY (P) PPGPP HAS BEEN CORRELATED DIRECTLY WITH THE ABILITY OF DIFFERENTIATION MORFOLÓGICA (ESPORULACIÓN) And FISIOLÓGICA (PRODUCTION METABOLITOS SIDE). MUTANTES RELC (RPLK) AND REAL IS PERJUDICADOS IN ESPORULACIÓN AND PRODUCED LESS ANTIBIÓTICO THE PARENTAL ECA. WORK IN THIS BE BUILT FOR TWO MUTANTES S. CLAVULIGERUS INVALID IN REAL, AND A MUTANTE RELC BY DELECIÓN OF 12 PB INTERNAL RPLK. BOTH MUTANTES INVALID REAL CARECÍAN PRODUCTION DETECTABLE DE (P) PPGPP, AND IS MOSTRARON INCAPACES OF FORM MICELIO AIR AND ESPORULAR. BUT BOTH MUTANTES REAL PRODUJERON UNTIL 6 AND 15 TIMES MORE CEFAMICINA CY ACID CLAVULÁNICO THE WILD ECA. THE MUTANTE RELC (RPLK) PRODUCÍA A 20% OF THE AMOUNT OF (P) PPGPP DETECTED ON THE WILD ECA, AND WAS PERJUDICADO IN ESPORULACIÓN BUT YES FORM MICELIO AIR. THIS MUTANTE MOSTRÓ A REDUCED SUMMARY OF ANTIBIOTICS, PRODUCIENDO BETWEEN 66 AND 79% LESS ACID CLAVULÁNICO AND 71 TO 84% LESS CEFAMICINA C THE PARENTAL ECA. STUDIES TRANSCRIPCIONALES MOSTRARON THAT MORE PRODUCTION OF ANTIBIOTICS FOR ECA DELECIONADA IN REAL TO BE GREATER TRANSCRIPT OF GENES FOR BIOSÍNTESIS OF ANTIBIOTICS, WHILE THE ECA RELC (RPLK) TENÍA A TRANSCRIPT OF REDUCED THE SAME. FURTHERMORE, SE CORRELACIONÓ IN THE WILD ECA A REDUCTION IN THE TRANSCRIPTION OF GENES OF BIOSÍNTESIS OF ANTIBIOTICS IN PARALLEL TO THE MAXIMUM OF PRODUCTION (P) PPGPP DURING THE ENTRY INTO PHASE ESTACIONARIA GROWTH. CONCLUDES THAT IS THE SUMMARY OF (P) PPGPP IS A REQUIREMENT FOR THE CORRECT DIFFERENTIATION MORFOLÓGICA IN S. CLAVULIGERUS, BUT NOT FOR BIOSÍNTESIS OF ANTIBIOTICS, FOR THAT AFFECTS NEGATIVAMENTE.

Author: CEPEDA GARCÍA CRISTINA.
Year: 2006.
University: LEÓN [www.unileon.es].
Place of defense: FAC. DE CIENCIAS BIOLÓ. Y AMBIEN..
Place of preparation: UNIVERSIDAD DE LEÓN.

Summary: The production of penicillin in P. Chrysogenum is subject to regulation by carbon source. The transcription factor CreA is responsible for this type of regulation of various genes, but until now had not proved their involvement in the regulation of carbon in the path of biosynthesis of penicillin in this fungus. This is the objective of this thesis. It has been shown that the box creA-1 present in the promoter gene pcbAB, which encodes the enzyme responsible for the first step of the route biosintética of penicillin in P. Chrysogenum, participates in the regulation of carbon that gene, because the mutation of this box causes an increase in gene expression pcbAB media supplemented with glucose. The mutation of the boxes creA-5 and creA-6 shows that, although they are functional and are involved in regulating carbon source for gene pcbAB, its importance is not comparable to that of the box creA-1. Moreover, the study itself protein CreA to see their involvement in the production of penicillin. The deletion of the gene creA resulted in a phenotype extreme, where they are both seriously altered the proper implementation of the mycelium as the production of penicillin. By the expression of antisense RNA has been determined that the attenuation of gene creA results in a greater production of penicillin, regardless of the source of the carbon in the middle, and this increase was accompanied by an increased expression of genes pcbAB and pcbC. Finally, overexpression of the gene creA resulted in a drastic reduction in the production of penicillin, which supports previous data and confirms that the factor CreA is responsible for the regulation of carbon source route biosynthesis pencilina P . Chrysogenum.

Author: Cartelle Gestal Mónica.
Year: 2006.
University: A CORUÑA [www.udc.es].
Place of defense: Facultad de Ciencias de la Salud.
Place of preparation: Facultad de Ciencias.

Summary: 1. Conducting studies of molecular epidemiology in clinical isolates of Enterobacteriaceae (Escherichia coli and Klebsiella spp) with B-lactamasas of spread spectrum (BLEE) isolated during the year 2001 in the area assisted by the University Hospital Complex Juan Canalejo. 2. Description of new B-lactamasas of spread spectrum (BLEE). 3. To study the implication of the position Arg276 in B-lactamasas type CTX-My its relationship with the resistance or sensitivity to inhibition by clavulanic. 4. Conducting studies in the key amino acid hydrolysis of cefotaxime in B-lactamasas of CTX-M type, using as a model the CTX-M-14 and CTX-M-1.

Author: FRANCO CIRERA SANDA.
Year: 2006.
University: BARCELONA [www.ub.es].
Place of defense: FACULTAD DE MEDICINA.
Place of preparation: FACULTAD DE MEDICINA.

Summary: The hepatitis C virus infects 800,000 people throughout Spain and around 200 million worldwide. HCV belongs to the family Falviviridae, whose genome (9.6Kb) is a molecule of RNA chain simple and positive polarity. A virus is highly variable and is distributed to quasiespecies. In Spain, about 50% of individuals infected with HIV-1, are co-infected with HCV. In this group of patients, HIV-1 accelerates the course of infection caused by HCV. There are 6 genotypes and several subtypes of HCV genotype remain prevalent in Spain, 1b in individuals monoinfectados with HCV, and genotypes 1a, 3a and 4 in individuals co-infected with HCV and HIV-1. The region NS3/4A protease is responsible for processing the proliproteína HCV and dismantle the defense through the block intracellular antiviral factor IRF-3. Two molecular Processing (TRIF i CARDIF), which are responsible for activating IRF-3 and produce IFN. The only available therapy is based on pegylated interferon and ribavirin, with a low percentage (40%) response in individuals infected with genotype 1 or 4. The search for new therapeutic alternatives based on regions of the HCV (NS3 and NS5B). It is a priority objective for clinical practice. In this thesis, it looks at population diversity at the level of nucleotide and amino acid, the proteases NS3/4A HCV co-infected two patients (VHC-VIH) and a patient monoinfectado (HCV), which have not received medical treatment for HCV. It explores the possible relationship between the quasiespecies in the region NS3 proteaasa (NS3pro) and the persistence dela disease. Assesses the catalytic activity of proteases obtained for each patient and trying to relate to the variability of gene NS3pro. Issues related to the catalytic activities of various genotypes of proteases and tries to see if there is any relationship between activity genotype and response to treatment. It explores the importance of protein NS4 in activity dela NS3pro and interaction between different cofactors and proteases genotype. Finally, it examines the potential phylogenetic relationships of two isolated HCV genotype 4, especially in regions implicated in response to treatment. It concludes that the distribution quasiespecies of NS3pro, both nucleotide and amino acid level is different in all three patients. This tells us that there are different selective forces acting on the three viral populations. Thus, in two of the three patients were detected resistance mutations to inhibieres of proteases. There is a wide margin of enzyme activity within each quasiespecie, indicating the great ability to tolerate this enzyme in environmental changes. The enzyme activity is determined for the cut point that is processed. In most combinations proteasas-cofactor different genotype, the change does not affect cofactor for the enzyme activity in certain combinations but is a total loss of activity of the enzyme, suggesting the importance of certain substitutions of NS3pro interacting with the cofactor. There is a coevolución between NS3pro and cofactor NS4A. Therefore, the interaction cofactor-enzima could be a potential target for the study of new inhibitors. The acquisition of two new genomes of genotype 4 suggests that this genotype is more phylogenetically related phenotype 1 not with other genotypes of the virus.

Author: Prado Prado Francisco.
Year: 2006.
University: SANTIAGO DE COMPOSTELA [www.usc.es].
Place of defense: Facultad de Farmacia.
Place of preparation: Facultad de Química.

Summary: In this Doctoral Thesis have developed theoretical models for prediction of antimicrobial activity (antibacterial, antifungal, and antiviral antiparasitaria) using methods for calculating molecular descriptors in combination with statistical techniques to establish a relationship between molecular structure and biological activity (QSAR methods). It im plementó to the objectives set our own methodology MARCH-INSIDE (Markovian Chemical In Silico Design). Additionally, in some cases, were developed medologías networks for predicting the mechanisms of pharmacological action of different compounds.