• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 2
  • 1
  • Tagged with
  • 3
  • 3
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Chemical studies of the glucose metabolism of Pseudomonas aeruginosa A.T.C. 9027

Idler, David Richard January 1950 (has links)
The first part of this work was undertaken in an effort to devise a satisfactory fractionation procedure for studying the phosphorylated intermediates in the glucose metabolism of P. Aeruginosa. By chemical and chromatographic analysis of these fractions it was hoped to obtain more information on the chemical sequence of the breakdown. A modified barium fractionation procedure is presented for isolating the trichloroacetic acid soluble phosphate esters from the cells of P. Aeruginosa. Several conclusions are drawn from the analysis of the barium fractions. The adenosine phosphate coenzyme system is shown to be present. Phosphoglyceric acid and hexose-di-phosphate are absent. Evidence is presented to show that glucose-6-phosphate is probably not present and neither phosphopyruvic acid nor the triose phosphates occur in detectable concentrations. These data all point to a phosphorylation mechanism which does not involve an Embden-Meyerhof system. Other than the coenzyme systems there are no nitrogenous compounds present. All fractions contain phosphate esters which have reducing values before hydrolysis. The reducing values, on hydrolysis with normal hydrochloric acid, parallel the release of inorganic phosphate. Every barium fraction contains a large percentage of non-phosphorylated compounds. These compounds are not reducing to the Folin-Malmros reagent. In the chromatography studies several solvents have been found satisfactory for the resolution of sugars, particularly pentoses. The presence of an arabinose phosphate is established by paper chromatography. Arabonic acid is also identified but the chromatographic evidence is not considered conclusive. The importance of these two compounds is discussed in the light of the present knowledge of glucose breakdown by P. Aeruginosa. A new developer is presented for use in the chromatography of certain phosphate esters. The second part of this work was undertaken in an effort to establish the chemical composition of the water and acid insoluble gum produced when P. Aeruginosa is grown on a glucose-mineral salts media. The amino acids present in the gum are alanine, glutamic acid and serine. These were identified by paper chromatography. Amino acid carbon dioxide accounts for 9.25% of the dry gum weight. The uronic acid content of the gum is 31.4%. The phosphorus content (as PO₄) is 13.2%. Fructose is present. The gum is very resistant to hydrolysis by four normal hydrochloric acid. Ten hours are required to liberate all carbon dioxide from the uronic acid component. The iodine reaction is negative. No sugars could be identified by paper chromatography. / Science, Faculty of / Chemistry, Department of / Graduate
2

Síntese biogênica de nanopartículas de prata por fungos marinhos /

Silva, Victória Corrêa da January 2019 (has links)
Orientador: Cristiane Angélica Ottoni / Resumo: As nanopartículas de prata (AgNP) oriundas da síntese biológica são descritas na atualidade como os novos agentes nanobiotecnológicos com potencial aplicação industrial e ambiental, principalmente devido a reconhecida atividade antimicrobiana. Dentre os diferentes organismos capazes de biossintetizar AgNP, os fungos filamentosos (Ff) se destacam, devido ao rápido crescimento e fácil escalonamento. Neste sentido, o presente estudo objetivou selecionar Ff marinhos, capazes de biossintetizar AgNP, assim como, otimizar o processo de síntese avaliando a influência de da concentração de AgNO3, biomassa, agitação, temperatura e pH. Também foi avaliada capacidade antimicrobiana e potencial efeito tóxico em camarão de água doce Palaemon pandaliformis. Dentre 12 linhagens Ff selecionadas, 10 apresentaram capacidade em biossintetizar AgNP. As AgNP produzidas pelas linhagens Penicillium citrinum IB-CLP11, Penicillium sclerotigenum IB-CLP17, Aspergillus niger IB-CLP20 e Penicillium polonicum IB-CLP22 apresentaram banda de ressonância plasmônica superficial no espectro em comprimento de onda compreendido entre 410-450 nm, tamanho compreendido entre 1-100 nm, carga com valor em módulo até o limite de 30 mV, índice de polidispersão inferior a 0,3. Nos estudos de ação antibacteriana, todas as 4 AgNP apresentaram capacidade em inibir o crescimento de Pseudomonas aeruginosa IPT322, Staphylococcus aureus IPT246 e Klebsiella pneumoniae IPT412 em concentração igual ou superior a 50 μg·mL-1 . Com r... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Silver nanoparticles (AgNP) from biological synthesis are currently described as the new nanobiotechnological agents with potential industrial and environmental application, mainly due to their recognized antimicrobial activity. Among the different organisms capable of biosynthesizing AgNP, filamentous fungi (Ff) stand out because of the rapid growth and easy staggering. Thus, the present study aimed to select marine fungi from the collection of culture of the Institute of Biosciences- Campus littoral Paulista (IB-CLP) of the state of São Paulo, which is able to biosynthesize AgNP, as well as optimize the synthesis process by evaluating the influence of different physico-chemical parameters, such, as variations concentrations in AgNO3, biomass, agitation, temperature and pH. An antimicrobial capacity and potential toxic effect were also evaluated in freshwater shrimp Palaemon pandaliformis. Among 12 selected strains of fungi, 10 were able to biosynthesize AgNP. All AgNP were characterized according to the proposed parameters and after 6 months of stability analysis, 4 presented a set of promising characteristics for the accomplishment of the second stage of the study. The AgNP produced by the Penicillium citrinum IB-CLP11, Penicillium sclerotigenum IB-CLP17, Aspergillus niger IB-CLP20 and Penicillium polonicum IB-CLP22 strains have surface plasmonic resonance band (SPR) in the wavelength range of 410-450 nm, size between 1-100 nm, load with module value up to the limit of 30 ... (Complete abstract click electronic access below) / Mestre
3

DESENVOLVIMENTO, CARACTERIZAÇÃO E AVALIAÇÃO DA ATIVIDADE ANTIMICROBIANA E ANTIBIOFILME DE NANOCÁPSULAS DE DIHIDROMIRICETINA EM CATETERES URINÁRIOS

Dalcin, Ana Júlia Figueiró 28 August 2015 (has links)
Submitted by MARCIA ROVADOSCHI (marciar@unifra.br) on 2018-08-16T20:20:00Z No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Dissertacao_AnaJuliaFigueiroDalcin.pdf: 1880693 bytes, checksum: 994407ff94e18668a6d303e7d72b7fd6 (MD5) / Made available in DSpace on 2018-08-16T20:20:00Z (GMT). No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Dissertacao_AnaJuliaFigueiroDalcin.pdf: 1880693 bytes, checksum: 994407ff94e18668a6d303e7d72b7fd6 (MD5) Previous issue date: 2015-08-28 / Nosocomial infections associated with biofilm formation in urinary catheters are among the leading causes of complications due to high antimicrobial resistance. An alternative is Dihydromyricetin (DHM), a flavonoid compound extracted mainly from grossedentata Ampelopsis plant, a vine of southern China, where you been widely used as a kind of healthy tea by the population. DHM has demonstrated different pharmacological properties. Among them stands out strong antimicrobial activity to various microorganisms.Therefore, the DHM has low lipid solubility consequently low biodisponibility. The nanoencapsulation can contribute to the improvement of the characteristics of drugs, as increased apparent solubility, protection against toxicity, increased drug activity and stability, sustained release and protection from degradation have been reported. The aim of this study was to evaluate the feasibility of DHM encapsulation and evaluate the influence on antimicrobial and antibiofilm activities in front of urinary catheters with Pseudomonas aeruginosa strains. The analytical method was devoloped and validated to indicate the stability of DHM and to determinaton it in polymeric nanocapsules by high-performance liquid chromatography. The developed method proved to be linear, specific, precise, accurate and robust for determining of DHM in polymeric nanocapsules. The results of the stability indicative studies demonstrated greater stability of nanocapsules than compared with free DHM, suggesting a protective the degradation of the nanostructure. The physicochemical characterization and the stability study of formulations demonstrated to be appropriate with nanometer diameter, positive zeta potential, the quantification of DHM close to the theoretical content, spherical morphology and uniform distribution of particles. The best conditions for storage of the suspensions without losing its physical and chemical characteristics during the period of 90 days was under refrigeration. The results showed that antimicrobial activity of the compound in the free form eliminate the microbial population in 12 hours while the nanocapsules containing DHM took 24 hours to remove the microbial population, extending up to 96 hours in a sustained manner. The antibiofilm activity of the formulations resulted in the eradication of biofilms both in free DHM formulations as in nanocapsules of DHM during the analyzed periods. However, within 96 hours the results of the inhibition of biofilm by DHM nanocapsules were more effective compared with free DHM, 67% of eradicating biofilm population. Thus, the formulation of nanocapsules DHM may be employed in the eradication of biofilms urinary catheters, it may be used as an innovative strategy. / As infecções hospitalares associadas à formação de biofilmes em cateteres urinários estão entre as principais causas de complicações devido à alta resistência antimicrobiana. Uma alternativa é a Dihidromiricetina (DHM), um composto flavonóide extraído principalmente da planta Ampelopsis grossedentata, uma videira do Sul da China, a qual te sido amplamente utilizada como uma espécie de chá saudável pela população. DHM tem demonstrado diferentes propriedades farmacológicas. Dentre elas destaca-se forte atividade antimicrobiana a diferentes microrganismos. Porém a DHM, possui baixa solubilidade lipídica, consequentemente baixa biodisponibilidade. A nanoencapsulação pode contribuir para a melhora das características de fármacos, pois aumento da solubilidade aparente, proteção contra toxicidade, aumento da atividade farmacológica e estabilidade, liberação sustentada e proteção contra degradações têm sido relatada. O objetivo do presente estudo foi avaliar a viabilidade da encapsulação e verificar sua influência sobre atividade antimicrobiana e antibiofilme em cateteres urinários frente a cepas de Pseudomonas aeruginosa. Foi desenvolvido e validado um método analítico indicativo de estabilidade para quantificação de DHM em nanocápsulas através de cromatografia líquida de alta eficiência. O método desenvolvido demonstrou-se linear, específico, preciso, exato e robusto para determinação de DHM em nanocápsulas poliméricas. Os resultados do estudo indicativo de estabilidade nas condições testadas demonstraram uma maior estabilidade da formulação de nanocápsulas de DHM quando comparada com DHM livre, sugerindo uma proteção da nanoestrutura frente às degradações. A caracterização físico-química e o estudo de estabilidade das formulações demonstraram-se adequadas com diâmetro nanométrico, potencial zeta positivo, teor próximo ao teórico, morfologia esférica e distribuição de partícula uniforme. A melhor condição para o armazenamento das suspensões sem perder suas características físico-químicas durante o período de 90 dias foi sob refrigeração. Os resultados da atividade antimicrobiana revelaram que o composto na forma livre eliminou a população microbiana em 12 horas enquanto as nanocápsulas contendo DHM levaram 24 horas para eliminar a população microbiana, estendendo-se até 96 horas de forma sustentada. A atividade antibiofilme das formulações resultou na erradicação dos biofilmes tanto nas formulações de DHM livre quanto nas nanocápsulas de DHM durante os períodos analisados. No entanto, em 96 horas os resultados da inibição do biofilme pelas nanocápsulas de DHM foram mais efetivos quando comparados com DHM livre, erradicando 67% da população do biofilme. Sendo assim, a formulação de nanocápsulas de DHM poderá ser empregada na erradicação de biofilmes em cateteres urinários, podendo ser utilizado como uma estratégia inovadora.

Page generated in 0.17 seconds