El presente es un estudio descriptivo, retrospectivo y de corte transversal, cuyo objetivo es determinar el patrón de resistencia a los antimicrobianos, de bacterias aisladas de muestras biológicas recolectadas de enero a diciembre del 2000 en el Centro Médico Naval, hospital de cuarto nivel ubicado en Bellavista, Callao. Fueron analizados 2215 antibiogramas, de los cuales el 74% se procesaron con el Sistema Microscan y el 26% por el Método de Difusión en Disco. El mayor porcentaje de aislados provenía de muestras de orina (60%) y vías respiratorias (30%). El microorganismo más frecuentemente aislado en urocultivos fue Escherichia coli (67%); y en vías respiratorias, Staphylococcus aureus (75%). Escherichia coli mostró resistencia mayor al 50% a las penicilinas, ampicilina/sulbactam, cefalotina, cotrimoxazol y tetraciclina, y 41% a ciprofloxacino. Los antibacterianos con mayor actividad frente a este microorganismo (resistencia <5%) fueron imipenem, meropenem, amikacina, ceftriaxona, cefpirome y aztreonam. Se encontró un 98% de resistencia de Staphylococcus aureus a la ampicilina, 17,3% a oxacilina y 5% a vancomicina. Cotrimoxazol y ciprofloxacino constituyen buenas alternativas terapeúticas contra este microorganismo, con 9 y 10% de resistencia respectivamente. Se encontró un alto grado de resistencia de Pseudomonas aeruginosa a imipenem (23%), ceftazidima (36%) y amikacina (45%). / -- This is a transversal, retrospective, descriptive study, which purpose is to determine the antimicrobial resistance level of bacteria isolated from biological samples collected from January through December 2000 at “Centro Médico Naval”, fourth level hospital, in Bellavista, Callao. 2215 antibiograms results were analyzed. Antimicrobial susceptibility testing was performed using the Microscan System (74%) and the Disk Diffusion Method (26%). Most of isolates were obtained from urine (60%) and respiratory tract samples (30%). Escherichia coli was the most frequent microorganism in urine (67%) and Staphylococcus aureus, in respiratory tract samples (75%). Escherichia coli showed resistance >50% to penicillins, ampicillin/sulbactam, cephalothin, trimethoprim-sulfamethoxazole and tetracycline, while 41% to ciprofloxacin. The most active antibiotics against this microorganism (resistance <5%) were imipenem, meropenem, amikacin, ceftriaxone, cefpirome and aztreonam. The most effective antibiotics against Staphylococcus aureus (resistance £10%) were vancomycin, trimethoprim-sulfamethoxazole, amikacin and ciprofloxacin. Staphylococcus aureus showed 98% resistance to ampicillin, 17,3% to oxacillin and 5% to vancomicin. Trimethoprim-sulfamethoxazole and ciprofloxacin, with 9 and 10% resistance respectively, are good therapeutic alternatives against this microorganism. Pseudomonas aeruginosa showed high resistance to imipenem (23%), ceftazidime (36%) and amikacin (45%). / Tesis

Los minerales arcillosos son utilizados frecuentemente en productos farmacéuticos como excipientes o sustancias activas. La interacción de un principio activo con el mineral puede influir sobre la liberación y estabilidad del compuesto, determinando su biodisponibilidad. El conocimiento de los aspectos químicos de los complejos principio activo-mineral arcilloso y los modos de adsorción y desorción constituyen una importante contribución en la formulación de sistemas de liberación modificada de sustancias basados en arcillas. Por otra parte, en los últimos años ha recibido especial atención el estudio de las consecuencias de la distribución de antibióticos en el medio ambiente, como consecuencia de su amplia utilización como preventivo y en el tratamiento de diversas infecciones, y la necesidad de desarrollar tecnologías para el control de la contaminación. Sólo recientemente los minerales arcillosos han sido utilizados para estos fines, a pesar de su amplia distribución en suelos y sedimentos y su elevada capacidad adsorbente. En este trabajo de tesis se estudió la adsorción de antibióticos de la familia de las tetra-ciclinas sobre montmorillonita bajo diferentes condiciones experimentales mediante espectroscopia UV-visible, dicroísmo circular, ATR-FTIR, difracción de rayos X y experiencias en batch y modelado teórico. Se evaluó también la capaci-dad de los complejos de adsorción antibiótico-montmorillonita para inhibir el crecimiento de bacterias de Escherichia coli. Los resultados obtenidos por métodos espectroscópicos sugieren importantes interacciones entre diversos grupos funcionales del antibiótico y la superficie del mineral. El aumento en el espaciado basal observado en los diagramas de rayos X revelan que las moléculas se encuentran intercaladas en el espacio intercapa de la montmorillonita. A partir de las experiencias en batch se observó que la adsorción de te-traciclina (TC) sobre montmorillonita depende del pH, fuerza iónica y catión de intercambio del mineral. La cantidad de TC adsorbida alcanza valores cercanos a la capacidad de inter-cambio del mineral a valores de pH menores a 4, donde prevalece la especie catiónica de TC, y luego disminuye al aumentar el pH. Los resultados experimentales y el modelo utilizado sugieren que en la adsorción de TC sobre mont-morillonita no sólo intervienen las especies catiónicas sino también neutras y monoaniónicas. Además de fuertes interacciones electrostáticas, pueden operar simultánea-mente varios tipos de interacciones que incluyen interacciones puente hidrógeno y fuerzas de van der Waals. Estos tipos de interacciones explican la adsorción de TC en un amplio intervalo de concentraciones, de pH y de fuerza iónica. Los estudios de actividad antimicrobiana, medida por el test de zona de inhibición, revelan que la actividad se mantiene cuando los antibióticos se encuentran adsorbidos sobre montmorillonita. La actividad antimicrobiana mostrada por los complejos de adsorción constituye un campo promisorio de aplicación, en particular para la formulación de productos tópicos. Por otro lado, la optimización del material adsorbente y de las condiciones de adsorción permite recomendar su utilización en la retención de antibióticos presentes en sistemas acuosos, utilizando minerales arcillosos de la NorPatagonia Argentina mediante técnicas simples y de bajo costo. / Clay minerals are often used in pharmaceutical products as excipients or active substances. The interaction of an active principle with the mineral can influence the release and sta-bility of the substance, determining its bioavailability. The knowledge of the chemical aspects of the active principle-clay mineral complexes and their adsorptiondesorption beha-viour constitute an important contribution to the formulation of clay based systems that can be used for modified release of substances. On the other hand, the study of the conse-quences of the antibiotic distribution in the environment has received special attention in the last years, as a consequence of its wide use in disease prevention and in the treatment of several infections, and of the need to develop technologies for contamination control. Only recently, clay minerals have been used for these purposes, in spite of its wide distribution in soils and sediments and its high adsorbent capacity. In this work the adsorption of antibiotics from the tetracycline family on montmorillonite has been studied under different experi-mental conditions by UV-visible spectroscopy, circular dichroism, ATR-FTIR, X ray diffraction and batch experiences and theoretical modelling. The capacity of the antibiotic-montmorillonite adsorption complexes to inhibit the grow of Escherichia coli bacteria was also studied. The results obtained with spectroscopic methods suggest important interactions between different antibiotic functional groups and the mineral surface. The increases in the basal spacing obser-ved inthe X-ray diagrams reveal that the molecules are intercalated in the montmorillonite interlayer space. Batch experiments have shown that tetracycline (TC) adsorption on montmorillonite depends on pH, ionic strength and the cation exchange capacity of the mineral. TC adsorption reaches values close to the cation exchange capacity at pH values lower than 4, where the TC cationic species prevails, and then it decreases as pH increases.The experimental results and the modelling suggest that both cationic as well as neutral and monoanionic species participate in the adsorption. Besides strong electrostatic interactions, several types of interactions can operate simultaneously including hydrogen bonds and van der Waals forces. These types of interactions explain TC adsorption in a wide interval of concentrations, pH and of ionic strength. The studies of antimicrobial activity, measured by the inhibition zone test, reveal that the activity remains when antibiotics are adsorbed on montmorillonite. Antimicrobial activity shown by the studied adsorption com-plexes constitutes a promising field of application, especially for the formulation of topical products. On the other hand, the optimization of the adsorbent material and of the adsorption conditions leads to recommend the use of clay minerals from the Argentinean Northern Patagonia for the retention of antibiotics in aqueous systems by using simple and low-cost techniques.

Tesis entregada a la Universidad De Chile en cumplimiento parcial de los requisitos para optar al grado de Magíster en Ciencias Biológicas. / El aumento en la aparición de microrganismos resistentes a los antibióticos es de gran preocupación en el ámbito de salud pública debido al aumento de la mortalidad y costos de tratamiento causado por las enfermedades que provocan. Se han detectado concentraciones de residuos de antibióticos sobre los niveles inhibitorios en aguas residuales, y los tratamientos actuales no son capaces de eliminar estos residuos. En relación con todo esto, los antibióticos de tipo tetraciclina son de gran interés debido a su alto uso, alto nivel de excreción y a su alta persistencia en el medio ambiente. Se ha reportado el uso de enzimas de tipo laccasa de hongos basidiomicetos para la oxidación de diferentes tetraciclinas mostrando distintas eficiencias. Sin embargo, las propiedades observadas aún están por debajo de lo requerido para una aplicación industrial y la optimización ha sido hasta ahora afrontada desde el ámbito de la Biocatálisis y no desde la Ingeniería de Enzimas. En este trabajo se estudió el uso de la laccasa del hongo ascomiceto Botrytis aclada expresada en P. pastoris para la oxidación de tetraciclinas, enzima que presenta una alta tolerancia a inhibición por iones cloruro y alta producción heteróloga. Se produjo y purificó la enzima y se probó su capacidad para oxidar oxitetraciclina e inactivar oxitetraciclina, clortetraciclina y tetraciclina. Bajo la hipótesis de que el sitio de unión de tetraciclinas corresponde al sitio canónico de las Laccasas y con la información disponible sobre el mecanismo catalítico, se modeló la interacción con estos 3 antibióticos y se calculó su energía de unión por métodos in silico. Además, las constantes de disociación de los distintos complejos fueron estudiadas in vitro mediante análisis de la inhibición competitiva ejercida por el antibiótico sobre la actividad de oxidación de ABTS de la laccasa. Observamos que la energía calculada correlaciona con la constante de disociación determinada para los tres antibióticos, mostrando una afinidad por Clortetraciclina > Tetraciclina > Oxitetraciclina. / The high apparition rate of antimicrobial resistant bacteria is of great concern for public health care due to the rise in mortality and the high cost associated to treat the illnesses caused by them. Antibiotic residual concentrations highly over the inhibitory levels have been detected in wastewaters. Now, wastewater treatment plants are not able to remove this kind of residues. In this matter, tetracycline antibiotics are of great concern due to their high use, high excretion rates and persistence in the environment. The use of Laccases from basidiomycetes for the oxidation of a variety of tetracyclines has been reported, showing variable performance. However, the observed oxidation rates are still under the required for industrial applications. Antibiotics removal has been optimized using approaches from the biocatalysis field and not from rational design enzyme engineer. In this work, we studied the use of laccase from Botrytis aclada, an ascomycete fungus, for the oxidation of tetracyclines. This enzyme shows high tolerance to chloride inhibition and high heterologous production rates. The enzyme was expressed and purified, and we proved its capacity to oxidase oxytetracycline and to inactivate oxytetracycline, and tetracycline. Having in mind the hypothesis that the binding site of tetracyclines is the canonical laccase active site, we modeled the interaction with those three antibiotics and calculated the energy of binding using in silico approaches. Also, we determined in vitro the dissociation constants of the complexes by analyzing inhibition kinetics using the antibiotic as a competitive inhibitor of the enzymatic ABTS oxidation. We observed a good correlation between the calculated Energy and the dissociation constants, showing higher affinity for Chlortetracycline > Tetracycline > Oxytetracycline. / CONICYT-PCHA/MagísterNacional/2016 – folio 22160435 y proyecto FONDEF-VIU16E0084. / Agosto 2019

Tesis presentada a la Universidad de Chile para optar al grado de Doctor en Bioquímica / La microcina E492 es un antibiótico peptídico de 7,9 kDa producido por Klebsiella pneumoniae RYC492 que mediante la formación de canales iónicos produce la despolarización de la membrana citoplasmática de bacterias gram negativo como E. coli, Salmonella, Citrobacter, Enterobacter y Klebsiella. Mediante estudios de clonamiento y expresión en E. coli se estableció que los determinantes genéticos implicados en la producción de microcina activa están contenidos en un segmento de 13 Kpb ubicado en el cromosoma de Klebsiella pneumoniae RYC492. La microcina E492 es exportada por un sistema de transporte de tipo I constituido por un transportador ABC (MceG), una proteína accesoria (MceH) y una proteína de membrana externa (TolC). El sistema de exportación de microcina E492 y el sistema de exportación de colicina V comparten alrededor de un 90% de similitud entre ellos. Estudios preliminares indicaron que el sistema de exportación de colicina V no reemplaza la función del sistema de exportación de microcina E492, y que la especificidad del transporte estaba relacionada con la presencia del gen mceF. El objetivo central de esta tesis consistió en estudiar los mecanismos de especificidad del sistema I de exportación para lo cual se usará como modelo los exportadores que permiten la secreción de colicina V y microcina E492. Mediante estudios de mutagénesis se determinó que MceF es prescindible en la exportación de microcina E492, y que más bien este producto génico participaría en la regulación de esta bacteriocina. Así, se determinó que MceF regula negativamente la expresión de la inmunidad de la microcina E492 y, posiblemente a través de este mecanismo, la expresión de la microcina E492. Para estudiar los determinantes de la especificidad de la exportación se clonaron los sistemas de exportación de microcina E492 (mceHG) y colicina V (cvaAB). Se determinó que el sistema de exportación de colicina no complementa la exportación de microcina E492. Mediante la construcción de sistemas de exportación híbridos entre las proteínas ABC y accesoria de los sistemas de microcina E492 y colicina V se estableció que el transportador de colicina V (CvaB) no permite la exportación de microcina E492. La construcción de transportadores quimeras entre los dominios del transportador de colicina V y microcina E492 permitió establecer que el dominio ABC del sistema de exportación de colicina V determina la exportación específica de su bacteriocina. Para entender los mecanismos moleculares de los determinantes de especificidad se generaron modelos 3D del transportador de microcina E492. Este modelo ayudó a predecir la importancia del residuo D121 en el procesamiento del péptido líder de la microcina E492, lo cual se comprobó experimentalmente. El modelo de MceG también permitió establecer que las diferencias entre los dominios ABC de los transportadores de microcina E492 y colicina V se localizan en una región específica. El modelo 3D también permitió entender la importancia de los cuatro últimos aminoácidos del transportador en el proceso de exportación, lo cual fue verificado experimentalmente. Esta región interactúa directamente con el nucleótido, elemento indispensable para energizar el sistema. Finalmente, se estudió mediante western blot de extractos celulares totales y extractos extracelulares de mutantes en los dominios peptidasa y ABC, el acoplamiento que existe entre el procesamiento de la bacteriocina y su exportación. Estos estudios indicaron que el procesamiento ocurre concomitante con la exportación y que el dominio ABC es necesario para activar a la peptidasa / Microcin E492 is peptide antibiotic of 7,9 kDa produced by Klebsiella pneumoniae RYC492 that through the formation of ion channels produces depolarization of cytoplasmatic membrane of gram-negative strains such as E. coli, Salmonella, Citrobacter, Enterobacter and Klebsiella. Through the cloning and expression in E. coli has been established that the genetic determinants involved in microcin E492 production are encoded in a 13 Kpb DNA segment from the chromosome of K. pneumoniae RYC492. Microcin E492 is secreted by a type I exporter system. This system is formed by an ABC transporter (MceG), an accessory protein (MceH), and the outer membrane protein TolC. The microcin E492 exporter system has more than 90% of similarity with the colicin V system. Preliminary studies showed that colicin V system is unable to replace the function of microcin E492 exporter, and this specificity was related to the mceF gene. The main goal of this thesis was to study the mechanisms of specificity in type I protein export system using as models colicin V and microcin E492 exporter systems. The use of mutants in MceF allowed to establish that MceF was not necessary to export microcin E492, and that this protein would participate in the regulation of microcin E492 expression. Thus, it was established that microcin E492 immunity is negatively regulated by MceF, and probably through this mechanism the expression of microcin E492 could be controlled. To study the elements that are involved in the specificity of export, the microcin E492 (mceHG) and colicin V (cvaAB) exporter systems were cloned. The colicin V exporter system was unable to complement the export of microcin E492. Through the construction of a hybrid between the accessory and exporter proteins of microcin E492 and colicin V exporter systems it was established that CvaB was unable to export microcin E492. The construction of chimeric proteins between the domains of microcin E492 and colicin V exporters showed that the ABC domain of colicin V exporter confers the specificity in the exportation of this bacteriocin. To understand the molecular mechanism of the specificity, 3D models of microcin E492 exporter were generated. These models helped to determine the importance of D121 residue in the processing of microcin E492 leader peptide. The 3D model of MceG allowed locate the region where the differences between the ABC domain of colicin V and microcin E492 exporters reside. The 3D model also permitted to assess the importance of MceG Cterminal region in the processing and export of microcin E492. This region also interacts directly with the nucleotide, a key step to energize the system. Finally, the coupling between microcin E492 processing and export was analyzed through western blot using intracellular and extracellular extracts of mutants in the ABC or peptidase domains. These studies showed that ABC domain is necessary to activate the peptidase

El género Enterococcus es conocido por ser de origen fecal o intestinal, pero tiene una amplia distribución en la naturaleza y se le puede encontrar en suelos, aguas, plantas y en productos alimenticios, siendo capaz de sobrevivir en medios poco enriquecidos. Los estudios reportados sobre estos microorganismos generalmente inciden en su aspecto clínico y su resistencia a antibióticos, y algunos se ubican en un contexto ambiental evaluando métodos para su detección o enumeración para uso en aguas recreacionales. Está aumentando la importancia de este microorganismo como agente causal de infecciones adquiridas en hospitales, pero el interés de estudio en este género radica en su alta resistencia natural a múltiples antimicrobianos y a su capacidad de adquirir y transferir dicha resistencia. Se sabe que Enterococcus es un microorganismo introducido al ecosistema marino debido a la contaminación de éste ambiente con desechos orgánicos, pero son pocos los reportes sobre estudios de resistencia antimicrobiana de éste género provenientes de muestras de agua de mar, siendo necesario este tipo de investigación que nos permita conocer la importancia de estos microorganismos en estos ambientes. / The genus Enterococcus is recognized as being of fecal origin but have a wide distribution in nature, they can be found in soil, water, plants and food products, being able to survive in low-enriched media. Studies on these microorganisms usually affect their appearance and clinical resistance to antibiotics, and there are some who are placed in an environmental context, evaluating methods of detection or enumeration in waters for recreational use. It is increasing the importance of this microorganism as a causative agent of infections acquired in hospitals, but the interest in this kind of study lies in its high natural resistance to multiple antimicrobials and their ability to acquire and transfer the resistance. Despite that Enterococcus is a microorganism introduced to the marine ecosystem by contamination with organic wastes, there are few reports on studies of antimicrobial resistance of the Enterococcus genus water samples from the sea, being necessary to this type of research that allows us to know the importance of these microorganisms in these environments.

Foram preparados novos derivados diferentemente substituídos da 3,5,8- triidróxi-4-imino-1 (4H)naftalenona. Estes novos derivados foram obtidos através de reações de acilação com cloretos de acila de cadeias lineares longas e de condensação com cetonas. Os novos derivados sintetizados foram testados quanto as suas utilidades potenciais como antibióticos, cristais líquidos e capacidade de complexação com metais de interesse analítico ou biológico. Estudou-se, também, reações de obtenção de novos derivados da 5-amino- 8-hidróxi-1 ,4-naftoquinona. / It has been prepared some new derivatives of 3.5.8-triidroxi-4-imino- 1 (4H)naphthalenone. This new derivatives were obtained through acylation reactions with acyl halides of long linear chains and condensation with ketones. The new sintetized derivatives have been submitted to some tests related with their potential use as antibiotics, liquid crystals and ability to complexate with metais of biological or analitical interest. We had also studied some reactions to obtain new derivatives of 5-amino- 8-hidroxi-1,4-naphthoquinone.

Este trabalho apresenta uma proposta de síntese de fotocatalisadores à base de titânia para fotodegradação dos antibióticos sulfametoxazol (SMX), ciprofloxacino (CIP) e norfloxacino (NOR). As sínteses foram realizadas utilizando suportes comerciais (sílica, alumina, óxido de magnésio e zeólita NaY), suportes modificados à base de sílica modificada com Al, Mo, W e Cr, e suportes modificados com Sn, a fim de de aumentar o espectro de absorção da radiação solar e promover uma maior interação entre catalisador e analito. Os sólidos foram caracterizados por diversas técnicas de caracterização elementar, estrutural, textural e morfológica: microscopia eletrônica de varredura com espectroscopia de emissão de raios X por dispersão de energia (SEM-EDX), difratometria de raios X (XRD), espectroscopia de refletância difusa no ultraviota-visível (DRS), potencial zeta, adsorção de nitrogênio, espalhamento de raios X a baixo ângulo (SAXS), espectroscopia no infravermelho (FT-IR) e espectroscopia fotoeletrônica de raios X (XPS). Em testes iniciais de degradação, os melhores resultados apresentados foram dos sólidos TiAl2O3 e SnTi-TiMoSiO2, atingindo respectivamente 84 e 71 % de degradação de SMX em água durante 60 minutos. Nos experimentos subsequentes, o sólido TiAl2O3 apresentou degradação de 100 % em água nos tempos de 20 minutos para os antibióticos CIP e NOR e 30 minutos para o SMX, e em efluente esses tempos foram para 60 e 90 minutos, respectivamente. O sólido SnTi-TiMoSiO2 apresentou 100 % de degradação em água para os antibióticos CIP e NOR em 120 minutos e em 60 minutos para o SMX, e a total degradação em efluente se deu em 60 minutos para CIP e NOR e em 90 minutos para o SMX. Em experimento utilizando a radiação solar como fonte luminosa, o sólido TiAl2O3 promoveu degradação total dos três antibióticos em apenas 15 minutos. O sólido SnTi-TiMoSiO2 possibilitou degradação de 100 % dos antibióticos CIP e NOR em 120 minutos e 70 % do SMX em 240 minutos. Avaliando a reutilização dos sólidos, TiAl2O3 apresentou degradação de 100% nos 5 ciclos de reutilização e o sólido SnTi-TiMoSiO2 apresentou degradação muito próxima de 100 %. / This study proposes a synthesis of photocatalysts based on titanium dioxide to photodegrade the antibiotics sulfamethoxazole (SMX), ciprofloxacin (CIP) and norfloxacin (NOR). The synthesis were performed using commercial supports as silica, alumina, magnesium oxide and NaY zeolite, modified supports with aluminum, molybdenum, tungsten and chromium, and modified surfaces with tin, in order to red shift the solar absorption spectrum and promote a major interaction between catalyst and analyte. The solids were characterized by many techniques of elemental, structural, textural and morphological characterization such as scanning electron microscopy/energy dispersive X ray spectroscopy (SEM-EDX), X ray diffraction (XRD), diffuse reflectance spectroscopy in ultraviolet-visible (DRS), zeta potential, nitrogen adsorption, small angle X ray scattering (SAXS), infrared spectroscopy (FT-IR) and X ray photoelectron spectroscopy (XPS). In the screening experiments the best results were found for TiAl2O3 and SnTi-TiMoSiO2 solids, reaching 84 % and 71 % of degradation of SMX, respectively, in pure water during 60 minutes. In subsequent experiments, TiAl2O3 alowed degradation of 100 % in pure water after 20 minutes of the antibiotics CIP e NOR and after 30 minutes of SMX, and in wastewater these degradation times shifted to 60 and 90 minutes, respectively. The solid SnTi-TiMoSiO2 showed 100 % degradation in pure water to antibiotics CIP and NOR in 120 minutes and 60 minutes for SMX, and total degradation in wastewater after 60 minutes for CIP and NOR and 90 minutes for SMX. The experiments using solar radiation as light source, TiAl2O3 presented total degradation of the three antibiotics in only 15 minutes, though the solid SnTi-TiMoSiO2 presented degradation of 100 % of CIP and NOR in 120 minutes and 70 % of SMX in 240 minutes. Evaluating the reuse of the photocatalysts, TiAl2O3 presented total degradation in all of 5 cycles of reusing and SnTi-TiMoSiO2 presented degradation very close to 100 %.

El género Enterococcus es conocido por ser de origen fecal o intestinal, pero tiene una amplia distribución en la naturaleza y se le puede encontrar en suelos, aguas, plantas y en productos alimenticios, siendo capaz de sobrevivir en medios poco enriquecidos. Los estudios reportados sobre estos microorganismos generalmente inciden en su aspecto clínico y su resistencia a antibióticos, y algunos se ubican en un contexto ambiental evaluando métodos para su detección o enumeración para uso en aguas recreacionales. Está aumentando la importancia de este microorganismo como agente causal de infecciones adquiridas en hospitales, pero el interés de estudio en este género radica en su alta resistencia natural a múltiples antimicrobianos y a su capacidad de adquirir y transferir dicha resistencia. Se sabe que Enterococcus es un microorganismo introducido al ecosistema marino debido a la contaminación de éste ambiente con desechos orgánicos, pero son pocos los reportes sobre estudios de resistencia antimicrobiana de éste género provenientes de muestras de agua de mar, siendo necesario este tipo de investigación que nos permita conocer la importancia de estos microorganismos en estos ambientes. / The genus Enterococcus is recognized as being of fecal origin but have a wide distribution in nature, they can be found in soil, water, plants and food products, being able to survive in low-enriched media. Studies on these microorganisms usually affect their appearance and clinical resistance to antibiotics, and there are some who are placed in an environmental context, evaluating methods of detection or enumeration in waters for recreational use. It is increasing the importance of this microorganism as a causative agent of infections acquired in hospitals, but the interest in this kind of study lies in its high natural resistance to multiple antimicrobials and their ability to acquire and transfer the resistance. Despite that Enterococcus is a microorganism introduced to the marine ecosystem by contamination with organic wastes, there are few reports on studies of antimicrobial resistance of the Enterococcus genus water samples from the sea, being necessary to this type of research that allows us to know the importance of these microorganisms in these environments.

Foram preparados novos derivados diferentemente substituídos da 3,5,8- triidróxi-4-imino-1 (4H)naftalenona. Estes novos derivados foram obtidos através de reações de acilação com cloretos de acila de cadeias lineares longas e de condensação com cetonas. Os novos derivados sintetizados foram testados quanto as suas utilidades potenciais como antibióticos, cristais líquidos e capacidade de complexação com metais de interesse analítico ou biológico. Estudou-se, também, reações de obtenção de novos derivados da 5-amino- 8-hidróxi-1 ,4-naftoquinona. / It has been prepared some new derivatives of 3.5.8-triidroxi-4-imino- 1 (4H)naphthalenone. This new derivatives were obtained through acylation reactions with acyl halides of long linear chains and condensation with ketones. The new sintetized derivatives have been submitted to some tests related with their potential use as antibiotics, liquid crystals and ability to complexate with metais of biological or analitical interest. We had also studied some reactions to obtain new derivatives of 5-amino- 8-hidroxi-1,4-naphthoquinone.

Submitted by Morgana Andrade (morgana.andrade@ufes.br) on 2016-04-13T21:32:23Z No. of bitstreams: 2 license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) DISSERTAÇÃO_ANALISE IN SILICO_PEPTIDEO ANTIMICROBIANOS.pdf: 5274880 bytes, checksum: d59f6bb66ce0d7814f525e182679a031 (MD5) / Approved for entry into archive by Patricia Barros (patricia.barros@ufes.br) on 2016-05-17T13:57:59Z (GMT) No. of bitstreams: 2 license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) DISSERTAÇÃO_ANALISE IN SILICO_PEPTIDEO ANTIMICROBIANOS.pdf: 5274880 bytes, checksum: d59f6bb66ce0d7814f525e182679a031 (MD5) / Made available in DSpace on 2016-05-17T13:57:59Z (GMT). No. of bitstreams: 2 license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) DISSERTAÇÃO_ANALISE IN SILICO_PEPTIDEO ANTIMICROBIANOS.pdf: 5274880 bytes, checksum: d59f6bb66ce0d7814f525e182679a031 (MD5) / A relação estabelecida entre os micro-organismos causadores de doenças e a humanidade vem de longa data, sendo as bactérias um dos principais agentes causadores de doenças na espécie humana, cujo controle pode ser por meio do uso de antibióticos, entretanto, com o passar do tempo, o surgimento e o aumento da resistência bacteriana ao uso de tais medicamentos tem se tornado uma preocupação crescente. Diante de perspectivas negativas ocasionadas pela multirresistência, o investimento em pesquisas que permitam a obtenção de novos medicamentos tem se tornado uma necessidade, porém, por mais dinâmicas que sejam as empresas farmacêuticas, a busca por novos antibacterianos não tem acompanhado o desenvolvimento da multirresistência. Desta forma, a elaboração de novas estratégias para o combate crescente a essa resistência tem recebida maior atenção, e os peptídeos antibacterianos (PAMs) surgem como uma perspectiva. Muitos PAMs já foram isolados de animais e plantas apresentando eficácia comprovada. Além de isolados diretamente de organismo diversos, outra possibilidade de obtenção de PAMs é a síntese artificial de peptídeos projetados ou ainda a utilização de peptídeos obtidos da fragmentação de moléculas orgânicas existentes na composição biológica normal dos seres vivos. Modelações computacionais permitem escolhas de peptídeos com maior eficácia e que possam exercer um combate efetivo contra micro-organismos multirresistentes, assim, o desenvolvimento e a validação de técnicas que usem a bioinformática para facilitar a descoberta desses PAMs e minimizar custos de pesquisa estão se destacando no campo da biotecnologia. Neste trabalho, foi selecionada a proteína eritropoetina humana (EPO) para a obtenção de PAMs por meio de simulações in silico. Os peptídeos obtidos foram avaliados e testados em diferentes modelos computacionais visando a predição de possíveis efeitos antibacterianos, pensando em uma eventual síntese para testes futuros, com a perspectiva de que esses agentes atuem como novas armas contra a constante evolução da resistência bacteriana, desde que não gerem respostas imunológica de rejeição, alergenicidade ou citotoxicida ao serem usados em terapias. / The relationship established between the micro-organisms disease causing and humanity has a long history, the bacteria being one of the main causative agents of disease in humans, some easily controlled others less, usually through the use of antibiotics, however, with the passage of time, the emergence and spread of bacterial resistance to the use of such medications has become a growing concern. In the face of negative perspectives caused by multi-resistance, investment in research that allows the obtaining of new drugs has become a necessity, however, even the pharmaceutical companies had been dynamic, the search for new anti-bacterials has not accompanied the development of multidrug resistance. Therefore, the development of new strategies to combat this growing resistance have received more attention, and antibacterial peptides (PAMs) arise as a perspective. Many PAMs have been isolated from animals and plants showing proven effectiveness. Beyond directly isolated from various organisms, another possibility of obtaining PAMs is design artificial synthesis of peptides or the use of peptides obtained from the fragmentation of organic molecules in the biological composition existing in the standard of living beings. Computational modeling allow choices of peptides more effectively and that may have an effective combat against multidrug-resistant micro-organisms, thus, the development and validation of techniques that use bioinformatics to facilitate the discovery of these PAMs and minimize search costs are excelling in the biotechnology field. In this work, we selected the human erythropoietin protein (EPO) to obtain PAMs through simulations in silico. The peptides were evaluated and tested in different computational models aimed at predicting possible antibacterial effects, considering a possible synthesis for future testing, with the prospect that these agents act as new weapons against the constant evolution of bacterial resistance, since there do not generate immune responses of rejection, allergenicity and cytotoxicity when used in therapies.