Made available in DSpace on 2014-06-11T19:27:24Z (GMT). No. of bitstreams: 0 Previous issue date: 2011-05-06Bitstream added on 2014-06-13T19:56:03Z : No. of bitstreams: 1 soaresjunior_j_me_rcla.pdf: 752217 bytes, checksum: cb7bfc540971b4b49bd12620984c3d88 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / O cancro cítrico é uma doença de importância mundial para o cultivo de laranjas e seu agente causador é a bactéria Xanthomonas axonopodis pv. citri. Embora todos os genes presentes nessa bactéria já tenham sido sequenciados, grande parte destas sequências não apresenta qualquer informação experimental sobre a contribuição para o sucesso da instalação do patógeno na planta hospedeira. Por outro lado, torna-se cada vez mais evidente que várias bactérias fitopatogênicas utilizam mecanismos de adaptação de origem genética que podem induzir efeitos fisiológicos na planta e adequar o ambiente de tal forma que permita a ocorrência da doença. Dentre estes mecanismos, está a possibilidade da bactéria produzir substâncias que se assemelhem a hormônios vegetais, como a auxina (AIA). O objetivo deste trabalho foi desenvolver metodologia genômica de busca para investigar se há genes que codificam para a produção de compostos iguais ou semelhantes a este hormônio em X. axonopodis pv. citri e se a sua participação no processo de patogênese é fundamental para o sucesso da infecção. Para tal, foi produzida coleção de mutantes genéticos funcionais aleatoriamente em X. axonopodis pv. citri, com posterior submissão desta mesma coleção a teste de produção de auxina utilizando o reagente Salkowski. Após produção e análise de grupo de mutantes dirigidos e coleção de aproximadamente 14200 mutantes aleatórios não foi detectada linhagem defectiva para a produção de AIA ou composto semelhante. Os resultados obtidos neste estudo, no entanto, mostram que a biossíntese do composto em X. axonopodis pv. citri é dependente do triptofano e que existe uma concentração ótima deste aminoácido a ser adicionado no meio de cultura para que a bactéria realize a biossíntese. Este é o primeiro estudo... / The citrus canker is a disease of global significance for the cultivation of oranges and its causative agent is the bacterium Xanthomonas axonopodis pv. citri. Although all the genes present in this bacterium have been sequenced, most of these sequences have no experimental information regarding the contribution to the successful installation of the pathogen on the host plant. On the other hand, it has been clearly demonstrated that several pathogenic bacteria use adaptative mechanisms that can induce physiological effects in plants and adjust the environment in a way that allows the occurrence of the disease. Among these mechanisms there is the possibility the bacteria produce substances that are similar to plant hormones such as auxin (IAA). The objective of this study was to develop a screening methodology to investigate the presence of genes that code for a compound identical or similar to auxins in X. axonopodis pv. citri as well as if it plays a role during the pathogenesis process. The main goal of this study was to produce a collection of random and directed genetic mutant strains of X. axonopodis pv. citri for the screening of auxin production by using the Salkowski reagent. After production and analysis of the group of mutants, including a collection of approximately 14,200 random mutant strains, defective production of IAA or similar compound was not detected. On the other hand, the results of this study show that such compound mimics effects of hormonal properties in X. axonopodis pv. citri and is dependent of tryptophan. In addition, it is shown that there is an optimum concentration of this amino acid to be added in the culture medium for the bacteria to carry out biosynthesis. To our knowledge, this is the first study to investigate systematically the production of auxin-like compounds in Xanthomonas axonopodis pv. citri.

Made available in DSpace on 2014-10-09T12:54:57Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:07:06Z (GMT). No. of bitstreams: 0 / Dissertacao (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP

Submitted by LETÍCIA RODRIGUES ALVES null (leticiarodalves@yahoo.com.br) on 2016-08-23T15:29:42Z No. of bitstreams: 1 AlvesLR_DISSERTAÇÃO+CERTIFICADO.pdf: 2471666 bytes, checksum: bbe3b90a7ad821bca3d2ff9e298beb5f (MD5) / Rejected by Ana Paula Grisoto (grisotoana@reitoria.unesp.br), reason: Solicitamos que realize uma nova submissão seguindo a orientação abaixo: A folha de aprovação deve constar após a ficha catalográfica. A versão submetida por você é considerada a versão final da dissertação/tese, portanto não poderá ocorrer qualquer alteração em seu conteúdo após a aprovação. Corrija esta informação e realize uma nova submissão contendo o arquivo correto. Agradecemos a compreensão. on 2016-08-24T16:10:04Z (GMT) / Submitted by LETÍCIA RODRIGUES ALVES null (leticiarodalves@yahoo.com.br) on 2016-09-05T16:31:58Z No. of bitstreams: 1 Dissertação_LR Alves - atualizada2.pdf: 1845174 bytes, checksum: 6d6d5923f6f594ad941d882c5beadab0 (MD5) / Approved for entry into archive by Juliano Benedito Ferreira (julianoferreira@reitoria.unesp.br) on 2016-09-06T12:52:43Z (GMT) No. of bitstreams: 1 alves_l_me_jabo.pdf: 1845174 bytes, checksum: 6d6d5923f6f594ad941d882c5beadab0 (MD5) / Made available in DSpace on 2016-09-06T12:52:43Z (GMT). No. of bitstreams: 1 alves_l_me_jabo.pdf: 1845174 bytes, checksum: 6d6d5923f6f594ad941d882c5beadab0 (MD5) Previous issue date: 2016-06-21 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / A contaminação por metais pesados é um problema mundial e é uma das causas mais severas de estresse abiótico nas plantas, desencadeando perdas na produtividade e risco de contaminação para a saúde humana. A concentração de cádmio aumentou consideravelmente no meio ambiente devido a fatores antropogênicos. As plantas podem absorver o cádmio, levando a alta produção de espécies reativas de oxigênio, o que desencadeia cascatas de oxidação descontroladas, resultando em danos a planta. Com o objetivo de adicionar novas informações nesta área, foi realizada uma discussão sobre a contaminação dos solos agrícolas por metais pesados, os danos causados na homeostase celular, o sistema antioxidante de defesa e o impacto para os consumidores. Além disso, foi feito um estudo sobre a comunicação da raiz para a parte aérea durante uma condição de estresse, interconectando a resposta especifica das espécies reativas de oxigênio e a ação dos hormônios nesta comunicação. Pare este propósito, foi utilizado como ferramenta a enxertia e os mutantes hormonais para investigar a modulação da resposta antioxidante de defesa entre os órgãos. / Heavy metal contamination is a worldwide concern and one of the most severe causes of abiotic stress in plants, triggering losses in crop production and contamination risks to human health. Cadmium concentration have been increased in environment due to several anthropogenic factors. Plants can uptake cadmium, which lead to a high production of reactive oxygen species and trigger an uncontrolled oxidation cascade in cells, resulting in damages to plant. In order to gain new information about this subject, we carried out a deep discussion about heavy metal contamination in agricultural soils, damages in cell homeostasis, antioxidant defense system and the impact to food consumers. Moreover, we studied root-to-shoot communication during stress condition and the specific responses of reactive oxygen species and hormones in this communication. For this propose, we used grafted hormonal mutants as a tool to investigate the modulation of antioxidant stress responses between organs. / FAPESP: 2013/27080-4

Made available in DSpace on 2014-10-09T12:54:57Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:07:06Z (GMT). No. of bitstreams: 0 / A saúde bucal, na maioria dos municípios brasileiros, constitui ainda um grande desafio aos princípios do Sistema Único de Saúde, principalmente no que se refere à universalização, à eqüidade do atendimento e alto custo envolvido na terapia restauradora. A procura pela descoberta de novos compostos metabólicos com atividade antibacteriana para a prevenção de doenças bucais e talvez com menores impactos a saúde e financeiros, seria muito importante para obtenção de um meio efetivo de controle da formação de um biofilme patogênico e da cárie dental. O objetivo deste trabalho é estudar a viabilidade biotecnológica do uso de venenos nativos de diferentes serpentes quanto à capacidade de inibir o crescimento de Streptococcus mutans, principal agente envolvido na cárie dental. Nossos resultados mostraram que os venenos das serpentes Bothrops moojeni e Bothrops jararacussu inibiram o crescimento de Streptococcus mutans e o componente responsável pela inibição parece ser a peróxido de hidrogênio. Apesar de ainda não totalmente conclusivos, os ensaios já realizados, permitem afirmar que venenos de serpentes são ferramentas importantes na inibição do crescimento de patógenos, especificamente daqueles envolvidos nas doenças cariogênicas. / Dissertacao (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP

Objetivo: Evaluar el efecto inhibitorio de la terapia fotodinámica (TPD) con Diodo Emisor de Luz (LED) azul sobre Streptococcus mutans y Streptococcus sanguinis en presencia y ausencia de riboflavina (E - 101). Materiales y métodos: Se realizaron cuatro tratamientos en presencia y ausencia de la exposición de luz LED azul y riboflavina al 0.5% sobre Streptococcus mutans y Streptococcus sanguinis. Las bacterias fueron cultivadas en medio BHI y la unidad de medida utilizada fue las unidades formadoras de colonias (UFC/ml). Resultados: La fotoactivación con luz LED azul a 40 segundos no tuvo efecto inhibitorio sobre S. mutans y S. sanguinis. Sin embargo, al realizar la terapia fotodinámica en presencia de riboflavina, se observó que el crecimiento bacteriano fue menor (p<0.05). Asimismo, se identificó que la viabilidad bacteriana de S. sanguinis es menor que la de S. mutans, con un 40% y 66% respectivamente. Conclusiones: Se concluye que la riboflavina tiene un efecto inhibitorio significativo sobre la viabilidad bacteriana de S. mutans y S. sanguinis. / Objective: To evaluate the inhibitory effect of photodynamic therapy (TPD) with blue Light Emitting Diode (LED) on Streptococcus mutans and Streptococcus sanguinis in presence and absence of riboflavin (E-101). Materials and methods: Four treatments were performed in presence and absence of blue LED and riboflavin (0.5%) exposure on Streptococcus mutans and Streptococcus sanguinis. The bacteria were grown in BHI medium and the unit of measurement used was the colony forming units (CFU / ml). Results: Photoactivation with blue LED light at 40 seconds had no inhibitory effect on S. mutans and S. sanguinis. However, when performing photodynamic therapy in presence of riboflavin, it was observed that bacterial growth was lower (p <0.05). Likewise, it was identified that bacterial viability of S. sanguinis is lower than S. mutans, with 40% and 66% respectively. Conclusions: It is concluded that riboflavin has a significant inhibitory effect on the bacterial viability of S. mutans and S. sanguinis. / Tesis

Objective: The aim of this study was to evaluate the antibacterial effect of Camellia sinensis (green tea) on Streptococcus mutans (ATCC 25175) and Streptococcus sanguinis (ATCC10556). Materials and Methods: The methanolic extract of green tea (commercial and bulk) was examined on Streptococcus mutans (ATCC 25175) and Streptococcus sanguinis (ATCC10556), using the well assay method. A total of 24 plates for the first extract (Commercial) and the same amount for the extract No. 2 (Bulk) were used and were divided into groups of 12 disks for each bacterium, with a total of 4 disks per group. In addition, each plate contained 3 disks embedded with tea and 1 disc with 0.12% chlorhexidine as a control group. Results: It was found antibacterial effect in both methanolic extracts of green tea. No statistically significant differences when comparing the natural green tea with the other extract, in every single microorganism. A p value of 0.18 and 0.63 respectively were obtained. The methanol extract of the commercial green tea had better antibacterial effect than the second extract with an average of 19.72 mm, for the second extract of green tea was 18.1 mm against Streptococcus mutans, whereas for Streptococcus sanguinis was 17.94mm and 16.46 mm respectively. The minimum inhibitory concentration (MIC) for the commercial and bulk extract was 0.08 gr/ml against Streptococcus mutans and 0.08 gr/ml and 0.25 gr/ml against the strains of Streptococcus sanguinis respectively. Conclusions: Both methanolics extracts, commercial and bulk have anti Streptococcus mutans (ATCC 25175) and Streptococcus sanguinis (ATCC10556) activity in vitro. The activity of commercial tea had better effects than the bulk methanolic extract. / Objetivo: Evaluar in vitro el efecto antibacteriano de la Camellia sinensis (té verde) frente al Streptococcus mutans (ATCC 25175) y al Streptococcus sanguinis (ATCC10556). Materiales y métodos: Se probaron dos extractos de té verde, uno comercial y otro a granel. Se utilizaron 24 discos para el primer extracto (Comercial) y la misma cantidad para el segundo extracto metanólico (Granel), se dividieron en grupos de 12 discos para cada bacteria, con un total de 4 placas petri por cada uno. Además, cada placa contenía 3 discos embebidos de té y 1 disco con Clorhexidina al 0.12% como grupo control. Estas muestras fueron analizadas con el método de difusión en agar con discos y los halos de inhibición se midieron a las 72 horas. Resultados: Se encontró efecto antibacteriano para ambos extractos probados. El promedio del halo de inhibición para el extracto de té verde comercial fue de 19.72 mm y para el extracto de té verde a granel fue de 18.1 mm frente al Streptococcus mutans, mientras que para el Streptococcus sanguinis la media obtenida fue de 17.94 mm y 16.46 mm respectivamente. Con respecto a la Concentración mínima inhibitoria (CMI), para el caso de Streptococcus mutans se determinó una CMI de 0.08 gr/ml para el extracto comercial y al extracto a granel. Mientras que para el caso de Streptococcus sanguinis la CMI fue de 0.08 gr/ml para el extracto comercial y de 0.25 gr/ml para el extracto a granel. Conclusiones: Ambos extractos metanólicos de té verde presentaron efecto antibacteriano contra las cepas del Streptococcus mutans (ATCC 25175) y Streptococcus sanguinis (ATCC10556). El té verde comercial fue el que presentó mayor efecto antibacteriano que el extracto a granel. / Tesis

The target was evaluate the “in vitro” antibacterial effect about five peruvian propolis on strains of Streptococcus mutans (ATCC 25175) and Streptococcus sanguinis (ATCC 10556), Having an experimental study design “in vitro” made in laboratorie of Microbiology of the Peruvian University of Applied Sciences. Materials and Methods: Sample size were about ten holes for each of the five extracts of propolis, either for Streptococcus mutans and Streptococcus sanguinis individualy. The antibacterial effect was developed with the technical “Agar overlay interference test”, which is used 200ml of Agar BHI homogenized with bacteria indispensably (a bottle for bacteria). This agar is distributed in the plates, once solidified the holes are made with 150μL of different kinds of propolis and the control group called Clorhexidine 0.12%. Completed this process is placed in the anaerobiosis chamber on 37º C, for 72 hours. Finally, the measurement of the inhibitory halo is made. Results: The methanolic extract of propolis of Oxapampa-Perú present inhibition halos in larger averaging of 33.15 + 3.26 mm against strains of Streptococcus mutans (ATCC 25175) and Streptococcus sanguinis (ATCC 10556), their average was about 23.23 + 0.82mm. In case of 4 extracts of commercial, just 3 of them (tincture of propolis Farmagel, Madre Nature y Kaita®), had bacterian activity in front of the studies strains. In all cases the antibacterian activity is less than positive control. Conclusions: The methanolic extract of propolis of Oxapampa-Peru, made in the laboratory has better antibacterian activity than commercial extracts against strains of Streptococcus mutans (ATTC 25175) and Streptococcus sanguinis (ATCC 10556). About the four commercial propolis evaluated on this study, propolis tincture Farmagel, Kaita®, Madre Natura and Max propolis tincture, only three of this have antibacterial activity against strains of de Streptococcus mutants (ATCC 25175) and Streptococcus sanguinis (ATCC 10556). / El objetivo fue evaluar in vitro el efecto antibacteriano de cinco propóleos peruanos sobre cepas de Streptococcus mutans (ATCC 25175) y Streptococcus sanguinis (ATCC 10556) teniendo un diseño de estudio experimental in vitro, realizado en el laboratorio de Microbiología de la Universidad Peruana de Ciencias Aplicadas. Materiales y métodos: se comparó el efecto antibacteriano de cuatro marcas comerciales de propóleo Tintura de propóleo Farmagel, Tintura de propóleo Max, Madre Natura, Kaita® y un extracto metanólico de propóleo de Oxapampa, el cual se elaboró en el laboratorio de Bioquímica de la UPC, como control (+) la clorhexidina al 0.12%. Para este estudio se utilizó 10 pocillos por cada extracto de propóleo, para el Streptococcus mutans y para el Streptococcus sanguinis individualmente. Se desarrolló con la técnica “Agar overlay interference test”, para lo cual se utilizó 200ml de Agar BHI homogenizado con las bacterias de manera independiente (un frasco por bacteria). Se distribuyó este agar en las placas, una vez solidificado se realizaron los pocillos con 150μL de los distintos tipos de propóleo y para el grupo control, se utilizó clorhexidina al 0.12%. Terminado este proceso se colocó en la cámara de anaerobiosis a 37°C, durante 72 horas. Por último, se realizó la medición del halo inhibitorio con una regla Vernier. Resultados: El extracto metanólico de propóleo de Oxapampa presentó halos de inhibición de mayor tamaño con una media de 33.15 + 3.26 mm frente a las cepas de Streptococcus mutans (ATCC 25175), para el Streptococcus sanguinis (ATCC 10556) su media fue de 23.23 + 0.82 mm. En el caso de los 4 extractos de propóleo comerciales, sólo 3 de ellos (Tintura de propóleo Farmagel, Madre Natura y Kaita®), tuvieron actividad antibacteriana frente a las cepas estudiadas, en todos los casos la actividad antibacteriana es menor que el control (+). Conclusiones: El extracto metanólico de propóleo de Oxapampa elaborado en el laboratorio tiene mayor actividad antibacteriana que los extractos comerciales frente a las cepas Streptococcus mutans (ATCC 25175) y Streptococcus sanguinis (ATCC 10556). De los 4 propóleos comerciales evaluados en el estudio, Tintura de propóleo Farmagel, Kaita®, Madre Natura y Tintura de propóleo Max, sólo tres de ellos tiene actividad antibacteriana frente a las cepas de Streptococcus mutans (ATCC 25175) y Streptococcus sanguinis (ATCC 10556). / The target was evaluate the “in vitro” antibacterial effect about five peruvian propolis on strains of Streptococcus mutans (ATCC 25175) and Streptococcus sanguinis (ATCC 10556), Having an experimental study design “in vitro” made in laboratorie of Microbiology of the Peruvian University of Applied Sciences. Materials and Methods: Sample size were about ten holes for each of the five extracts of propolis, either for Streptococcus mutans and Streptococcus sanguinis individualy. The antibacterial effect was developed with the technical “Agar overlay interference test”, which is used 200ml of Agar BHI homogenized with bacteria indispensably (a bottle for bacteria). This agar is distributed in the plates, once solidified the holes are made with 150μL of different kinds of propolis and the control group called Clorhexidine 0.12%. Completed this process is placed in the anaerobiosis chamber on 37º C, for 72 hours. Finally, the measurement of the inhibitory halo is made. Results: The methanolic extract of propolis of Oxapampa-Perú present inhibition halos in larger averaging of 33.15 + 3.26 mm against strains of Streptococcus mutans (ATCC 25175) and Streptococcus sanguinis (ATCC 10556), their average was about 23.23 + 0.82mm. In case of 4 extracts of commercial, just 3 of them (tincture of propolis Farmagel, Madre Nature y Kaita® ), had bacterian activity in front of the studies strains. In all cases the antibacterian activity is less than positive control. Conclusions: The methanolic extract of propolis of Oxapampa-Peru, made in the laboratory has better antibacterian activity than commercial extracts against strains of Streptococcus mutans (ATTC 25175) and Streptococcus sanguinis (ATCC 10556). About the four commercial propolis evaluated on this study, propolis tincture Farmagel, Kaita® , Madre Natura and Max propolis tincture, only three of this have antibacterial activity against strains of de Streptococcus mutants (ATCC 25175) and Streptococcus sanguinis (ATCC 10556). / Tesis

Background: The antibacterial activity of restorative materials has an important role in the prevention of recurrent caries. Objectives: To compare the antibacterial activity of three glass ionomer cements Ketac Molar®, Fuji II® and Maxxion R® against Streptococcus mutans (ATCC 25175) and Streptococcus sanguinis (ATCC 10556). Materials and methods: The study was experimental in vitro and consisted of the evaluation of the antibacterial activity of three glass ionomer cements: Ketac Molar®, Fuji II LC ® and Maxxion R®. he which were prepared in accordance with the manufacturer's recommendations and was inserted into wells made with sterile disposable tips using the CENTRIX® system in petris plaques with agar BHI. Furthermore, the antibacterial activity was evaluated by using a caliper to measure the diameter of the growth inhibition zones of strains tested; also, tested; Also, the survival and proliferation of bacteria on ionomers was evaluated by the method of the reduction of 3- (4,5- dimethylthiazol-2-yl) -2,5-diphenyl tetrazolium bromide (MTT) analysis. As the viability of Streptococcus mutans was 1.221nm for Ketac Molar®, 0.457nm for Maxxion R® and 0.804nm for Fuji II®. Also the viability of Streptococcus sanguinis was Ketac 0.3175nm for Molar®, for 1.195nm and 0.276nm Maxxion R® for Fuji II®. Results: Ketac Molar®, Fuji II® and Maxxion R® showed inhibition halos 16.27mm ± 1.62, 11.95 ± 1.51 mm and 12.38 mm ± 2.55 against strains of Streptococcus mutans respectively with p = 0.0001, which means that there statistically significant difference. Furthermore, inhibition halos Ketac Molar®, Fuji II® and Maxxion R® against Streptococcus sanguinis were 10.11mm ± 1.42, 2.34 ± 13.51mm and 10.83mm ± 1.22 respectively with p =0.0008, demonstrating that there is also significant difference. Conclusion: The three GIC under evaluation showed halos of growth inhibition of cariogenic bacteria assayed. However, Ketac Molar® had greater antibacterial activity against Streptococcus mutans; while the Fuji II® had greater antibacterial activity against Streptococcus sanguinis. / Introducción: la actividad antibacteriana de los materiales de restauración tiene un papel importante en la prevención de caries recidivante. Objetivos: comparar la actividad antibacteriana de tres ionómeros de vidrio Ketac Molar®, Fuji II LC® y Maxxion R® contra cepas Streptococcus mutans (ATCC 25175) y Streptococcus sanguinis Materiales y métodos: el estudio fue experimental in vitro y consistió en la evaluación de la actividad antibacteriana de tres ionómeros de vidrio: Ketac Molar®, Fuji II LC® y Maxxion R®, los cuáles fueron preparados en cumplimiento de las recomendaciones del fabricante y se insertaron en pozos confeccionados con puntas desechables estériles utilizando el sistema Centrix® en placas de petri con agar BHI. Por otro lado, la actividad antibacteriana se evaluó mediante el uso de un vernier para medir el diámetro de los halos de inhibición del crecimiento de las cepas ensayadas; asimismo, se evaluó la supervivencia y proliferación de las bacterias sobre los ionómeros mediante el método de la reducción de 3-(4,5-Dimetiltiazol-2-yl)-2,5-difenil tetrazolio bromuro (MTT).En cuanto al análisis de la viabilidad del Streptococcus mutans fue de 1.221nm para el Ketac Molar®, 0.457nm para el Maxxion R® y 0.804nm para el Fuji II®. Asimismo, la viabilidad del Streptococcus sanguinis fue de 0.3175nm para el Ketac Molar®, 1.195nm para el Maxxion R® y 0.276nm para el Fuji II®. El estudio se realizó por triplicado y el análisis estadístico utilizó la prueba de ANOVA a 3 criterios. Resultados: el Ketac Molar®, Fuji II® y Maxxion R® mostraron halos de inhibición de 16.27mm ± 1.62, 11.95 mm ± 1.51 y 12.38 mm ±2.55 contra cepas de Streptococcus mutans respectivamente con un p= 0.0001, lo que significa que existe diferencia estadísticamente significativa. Asimismo, se encontraron halos de inhibición del Ketac Molar®, Fuji II® y Maxxion R® contra cepas de Streptococcus sanguinis de 10.11mm ±1.42, 13.51mm ±2.34 y 10.83m m ±1.22 respectivamente con un p= 0.0008, lo que demuestra que también existe diferencia significativa. Conclusión: los tres cementos de ionómero de vidrios evaluados, presentaron halos de inhibición del crecimiento de las bacterias cariogénicas ensayadas. Sin embargo, el Ketac Molar® tuvo mayor actividad antibacteriana contra el Streptococcus mutans ; mientras que el Fuji II® tuvo mayor actividad antibacteriana contra el Streptococcus sanguinis. / Tesis

Après la découverte des mutations de la calréticuline dans les néoplasmes classiques myéloproliferatifs négatifs pour le Ph1, les travaux se sont focalisés sur les deux mutations les plus fréquentes, c'est-à-dire la calréticuline del52 et l’ins5, mais il existe environ 20% de mutants rares de la calréticuline (une cinquantaine), qui ont été classés en type-1 « like » et type-2 « like », classification basée sur leur structure. Cependant il reste à déterminer si cette classification est pertinente du point de vue fonctionnel, ce qui pourrait avoir des conséquences pour la prise en charge des patients et leur traitement. Ici, nous démontrons que deux mutants rares de type-1 (del34 et del46) et un de type-2 (del19) se comportent de manière similaire aux deux mutations fondatrices de cette classification, del52 et ins5, respectivement. Ces résultats ont été validés par des expériences in vivo chez la souris. Tous les mutants de la calréticuline (del19, del34 et del46) nécessitent absolument le récepteur de la thrombopoïétine, appelé MPL, pour induire une transformation cellulaire en provoquant une activation indépendante de la thrombopoïétine de la voie MPL / JAK2-STAT, comme les mutants del52 et ins5. Dans les expériences de transplantation de moelle osseuse de souris, les mutants rares de type-1 sont associés à une progression fréquente de la maladie d’un tableau proche d’une thrombocytémie essentielle à une myélofibrose, tandis que le mutant rare de type 2 est associé à une légère thrombocytose. Du point de vue hématopoïétique, les mutants rares de type-1 provoquent une amplification au niveau des cellules souches hématopoïétiques donc à un stade précoce tandis que les mutants rares de type-2 provoquent une amplification tardive de la mégacaryopoïèse. Grâce à une modélisation protéique basée sur l'homologie des mutants de calréticuline, nous avons identifié des domaines oncogènes qui seraient potentiellement responsables de l'interaction pathologique de la calréticuline et de MPL pour conduire à une activation indépendante de la thrombopoïétine. Maintenant, ces résultats in silico doivent être absolument validés par des études structure fonction. Enfin, nous avons modélisé un nouveau mécanisme de signalisation dans la leucémie myéloïde chronique comprenant IRE-1alpha, un bras de la voie de réponse des protéines mal repliées (UPR), qui pourrait être responsable de la perte de la fonction de la p53 pendant la progression de la leucémie myéloïde chronique vers une leucémie aiguë. Un tel mécanisme pourrait être impliqué dans les autres MPN. / After the discovery of calreticulin mutations in classical Ph1- Myeloproliferative Neoplasms, extensive investigation is underway on the two most frequent mutations, i.e., del52 and ins5, but it remains that the rare calreticulin mutants, which include both type-1 like and type-2 like require a similar investigation for ascertaining whether the classification of type-1 and type-2 has a functional relevance as well as for therapeutic intervention and patient management. Here we demonstrate that type-1 like (del34 and del46) and type-2 like (del19) mutants behave similarly as del52 and ins5 mutants, respectively. Moreover, we validate our findings with in vivo experiments. All the calreticulin mutants (del19, del34 and del46) absolutely require the thrombopoietin receptor, MPL, to induce cell transformation by causing ligand independent activation of the MPL/JAK2-STAT pathway. In mouse bone marrow transplantation experiments, type-1 like mutants are associated with frequent progression from an essential thrombocythemia-like phenotype to myelofibrosis whereas type-2 like mutant is associated with mild thrombocytosis. Type-1 like mutants cause clonal amplification of early hematopoetic stem cells whereas the type-2 like mutant causes late platelet amplification. Further, by homology based protein modeling of calreticulin mutants, we have identified possible oncogenic domains responsible for pathologic interaction of CALR and MPL leading to ligand independent activation of MPL. Now they must be validated by structural-functional studies Finally, we have modelled a novel signaling mechanism in chronic myeloid leukemia comprising of IRE-1alpha, an unfolded protein response (UPR) pathway arm, which may be responsible for loss of the WT p53 function during leukemic development and progression. Such a mechanism may be involved in the other MPNs

The bacterial ribosome is an important target for many antimicrobial agents. Aminoglycoside antibiotics bind to both 30S and 50S ribosomal subunits, inhibiting translation and subunit formation. During ribosomal subunit biogenesis, ribonucleases (RNases) play an important role in rRNA processing. E. coli cells deficient for specific processing RNases are predicted to have an increased sensitivity to neomycin and paromomycin. Four RNase mutant strains showed an increased growth sensitivity to both aminoglycoside antibiotics. E. coli strains deficient for the rRNA processing enzymes RNase III, RNase E, RNase G or RNase PH showed significantly reduced subunit amounts after antibiotic treatment. A substantial increase in a 16S RNA precursor molecule was observed as well. Ribosomal RNA turnover was stimulated, and an enhancement of 16S and 23S rRNA fragmentation was detected in E. coli cells deficient for these enzymes. This work indicates that bacterial RNases may be novel antimicrobial targets.