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published_or_final_version / Dentistry / Master / Master of Dental Surgery

Diss. (sammanfattning) Stockholm : Karol. inst., 2002. / Härtill 5 uppsatser.

Thesis (Ph.D.)--University of Nebraska-Lincoln, 2009. / Title from title screen (site viewed June 26, 2009). PDF text: xii, 196 p. : ill. (some col.) ; 3 Mb. UMI publication number: AAT 3352311. Includes bibliographical references. Also available in microfilm and microfiche formats.

Thesis (M.S.)--Oregon State University, 2008. / Printout. Includes bibliographical references (leaves 133-139). Also available on the World Wide Web.

Thesis (M.S.)--University of Delaware, 2006. / Principal faculty advisor: Carlton R. Cooper, Dept. of Biological Sciences. Includes bibliographical references.

Group A Streptococcus (GAS) is responsible for mild and common infections like tonsillitis and pharyngitis, and more serious invasive disorders like necrotizing fasciitis and glomerulonephritis. The ability to invade tissues is closely linked to the virulence factors expressed by the bacterium. Hyaluronic acid capsule expression is variable among all the strains in S. pyogenes and confers the capacity to evade the immune response. In a previous study, it was found that capsule production in CovR mutants was temperature-regulated, showing no capsule production at 37℃ but increased production was observed at 25℃. In this study, the objective is to find the elements involved in the thermoregulation using a genetic approach. First, mutants were created by knocking-out CovR, the response regulator of the CovRS two-component system that controls about 15% of GAS genome. Transposon mutants were screened to find changes in capsular phenotype. Colonies expressing capsule at 37℃ were selected for sequencing. The sequencing revealed three different events in different mutants. Two of them pointed at hypothetical proteins, one of them, SpyM3_1255, was phage associated protein with a DnaD domain and the other one, SpyM3_1377, encoded cvfA. A third over-producer mutant showed an insertion in the promoter area of the has operon, the operon that encodes for hyaluronan synthase production, upstream from other disruptions in the promoter area that generated non-producing mutants. This suggest that there is more than one factor involved in thermoregulation of capsule production.

Orientadores: Maria Helena Andrade Santana, Luciana Rocha Barros Gonçalves / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Quimica / Made available in DSpace on 2018-08-09T08:38:08Z (GMT). No. of bitstreams: 1 Macedo_AndreCasimirode_M.pdf: 4092684 bytes, checksum: 33a14c0e2d223f5ac233f286ca1249ba (MD5) Previous issue date: 2007 / Resumo: O ácido hialurônico (AH) é um mucopolissacarídeo presente nos tecidos conjuntivos de animais. Possui aplicações nas áreas médico-farmacêutica, como veículo para encapsulação e liberação de bioativos, além de aplicações em cosméticos. Este trabalho, apresenta um estudo da produção de AH utilizando suco de caju como substrato em processos de fermentação submersa (FS) e bagaço de caju como substrato/suporte em cultivo no estado sólido (FES). Em ambos os casos o inóculo foi preparado com cepa de Streptococcus zooepidemicus (ATCC 39920), cultivado em suco de caju in natura enriquecido com extrato de leveduras. Os ensaios em FS foram feitos utilizando suco de caju in natura e suco de caju clarificado através de microfiltração tangencial em sistema de membranas cerâmicas (0,2 mm), à 250 rpm e 2 vvm de ar. Ensaios de FES foram feitos em sistemas de colunas de leito fixo (colunas de Raimbault), com altura de leito 3 cm e vazão de ar 0,4 L/min. Os processos foram caracterizados com base nos parâmetros cinéticos, produtividades em AH e em biomassa bacteriana,transferência de oxigênio e evolução da viscosidade do meio. O AH produzido foi identificado por FTIR e caracterizado através da sua massa molar e distribuição. Os resultados mostraram que em ambos os processos a aeração é fundamental para o crescimento celular e produção de AH. Não houve diferenças expressivas nos parâmetros do processo para a fermentação submersa conduzida com suco de caju in natura ou clarificado. A máxima concentração de AH obtida na FES foi de 0,007 g/g de bagaço e na FS 2,61 g/L. As distribuições de massa molar mostram que o AH produzido em FES encontra-se nas faixas de 104 e 105 Da, enquanto que para a FS prioritariamente é produzido AH na faixa de 103 e 104 Da / Abstract: Hyaluronic acid (HA) is a mucopolysaccharide component of animal connective tissues. It has been reported important applications of HA in medical, pharmaceutical and cosmetic area as well as a vehicle for encapsulation and delivery of bioactive products. This work presents a study of HA production using cashew apple juice as substrate in submerse fermentation (SF) and cashew apple bagasse as substrate/support in solid state fermentation (SSF). In both cases the inoculum was prepared from a Streptococcus zooepidemicus strain (ATCC 39920), cultured in the in natura juice enriched with yeast extract. In natura or clarified juices were used in SF assays at 250 rpm and 2 vvm of air. The clarification was carried out through tangential microfiltration in ceramic membrane system (0,2 mm). Fixed bed columns (Raimbault¿s columns) at 3 cm bed height and air flow rate 0.4 L/min were used in FES assays. The Processes were characterized based on the kinetic, HA and biomass productivities, oxygen transfer and medium viscosity parameters. The produced HA was identified by FTIR and characterized trought its molecular weight and distribuition. The experimental results showed that aeration is fundamental for cell growth and HA production in both processes. There were no significant differences in the parameters for SF using in natura or clarified juices. The maximum HA concentration obtained by SSF was 0.007 g/(g of bagasse) and 2.61 g/L for SF. The main distribution of molecular weight was 104 to 105 Da for SSF and 103 to 104 Da for SF / Mestrado / Desenvolvimento de Processos Biotecnologicos / Mestre em Engenharia Química

Orientador: Maria Helena Andrade Santana / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Química / Made available in DSpace on 2018-08-25T22:51:52Z (GMT). No. of bitstreams: 1 Oliveira_RhelvisdeCampos_M.pdf: 1444700 bytes, checksum: 22be4f55322956156176e0226207310e (MD5) Previous issue date: 2014 / Resumo: O ácido hialurônico (AH) é um polissacarídeo linear com diversas aplicações nas áreas médica e farmacêutica. A produção de ácido hialurônico por via fermentativa vem sendo muito estudada atualmente e modificações no meio de cultura tornaram - se uma das principais alternativas para se atingir um produto com altos níveis de rendimento e massa molar (MM). A primeira etapa deste trabalho teve como objetivo estudar os efeitos de duas peptonas de soja, cuja principal diferença se encontra nas concentrações dos aminoácidos aspartato glutamina e glutamato (AGG), além das proporções de aminoácidos livres e totais. O microrganismo Streptococcus zooepidemicus ATCC 39920 foi cultivado por 24h em frascos agitados contendo uma concentração inicial de 25g L-1 de glicose e razões Carbono:Nitrogênio (C:N) de 3,4:1, 4,1:1 e 5,5:1 para a peptona rica em AGG e 4,1:1, 4,9:1 e 6,3:1 para a peptona pobre em AGG. Os resultados mostraram que a maior produção de AH foi de 1,37g L-1 à razão C:N de 4,1:1 para a peptona pobre em AGG, com MM média de 8,9x10 3 Da e cerca de 50 % das frações de MM na casa de 104 Da, enquanto que para a peptona rica em AGG esses valores foram de 0,70g L-1 e 4,1:1 em termos de produção de AH e razão C:N respectivamente, com MM média de 1,19x106 Da e cerca de 67 % das frações de MM na casa de 105 Da. Na segunda parte deste trabalho foi feita uma comparação do comportamento cinético de fermentações realizadas com as duas peptonas de soja em ensaios com aeração forçada. Os modelos logísticos de Verhulst para o crescimento celular, um análogo ao modelo de Luedeking-Piret incorporando o modelo logístico de Verhulst para o consumo de glicose, Verhulst modificado e Luedeking¿Piret para a produção de AH foram utilizados para estimar os parâmetros cinéticos. Os ajustes dos modelos apresentaram coeficientes de correlação maiores que 0,93. Os resultados mostraram que crescimento celular, consumo de glicose e produção de AH ocorreram durante as 24h de cultivo em meio de cultura contendo a peptona rica em AGG, enquanto que para a peptona pobre em AGG esse tempo reduziu para 10h. A quantidade produzida de AH foi semelhante para ambas as peptonas, entretanto, utilizando a peptona pobre em AGG, 60% da concentração final de AH veio da fase anterior à etapa de fermentação propriamente dita. Os parâmetros cinéticos apresentaram um coeficiente de manutenção maior para o cultivo com a peptona pobre em AGG e maior consumo de glicose foi verificado no cultivo com a peptona rica em AGG, refletindo-se no no rendimento YX/S, enquanto que o rendimento YP/X foi semelhante nos cultivos com ambas as peptonas. Esses resultados mostram que as peptonas não são somente fontes de nitrogênio, mas desempenham papéis específicos no cultivo celular / Abstract: Hyaluronic acid (HA) is a linear polysaccharide with many applications in the medical and pharmaceutical fields. The production of hyaluronic acid by fermentation pathway has been widely studied nowadays, and modifications made in the culture medium is one of the main alternatives to achieve a product with high levels of yield and molecular weight (MW). The first step of this work was to study the effects of two soy peptones, whose main difference is the amino acids concentrations of aspartate, glutamine and glutamate (AGG), and the proportions of free and total amino acids. The microorganism Streptococcus zooepidemicus ATCC 39920 was grown over 24 hours in shake flasks containing initial glucose concentration of 25 g L-1 and the same carbon: nitrogen (C: N) ratios 3.1:1, 1.7:1 and 1.0:1 for both peptones. The results showed that the higher production of HA was 1.37g L-1 with C:N ratio of 1.0:1 for poor AGG peptone with average MW of 8.9 x 103 Da and about 50 % of the MW fraction in the range of 104 Da, while rich AGG peptone showed values of 0.70 g L-1 and 1.7:1 in terms of HA production and C:N ratio respectively, with average MW of 1.19 x 106 Da and about 67% of the fractions of MW in the range of 105 Da. In the second part of this work was made one comparison of the kinetic behavior of cultivations using both peptones in assays with forced aeration. The logistic models of Verhulst for cell growth, analogous to Luedeking-Piret model incorporating the logistic model of Verhulst for glucose consumption, Verhulst modified and Luedeking-Piret for the production of HA were used to estimate the kinetic parameters. The adjustments of the models had correlation coefficients greater than 0.93. The results showed that cell growth, glucose consumption and HA production occurred over the 24 hours of cultivation in culture medium with rich AGG peptone, while with poor AGG peptone this time reduced for 10h. The amount of HA produced was similar for both peptones, however, using poor AGG peptone 60% of the final HA concentration came from the previous stage of the fermentation. The kinetic parameters showed higher coefficient of maintenance for cultivation with poor AGG peptone and increased glucose consumption was observed in cultivation with rich AGG peptone, reflected in terms of YX/S yield, while the yield YP/X was similar in cultivations with both peptones. These results show that peptones are not only sources of nitrogen but play specific roles in cell culture / Mestrado / Desenvolvimento de Processos Biotecnologicos / Mestre em Engenharia Química

In the world today, asthma affects more than 235 million people. The widespread prescription of inhaled corticosteroids—the current gold standard of asthma control medication—allows many asthmatics to live symptom-free and has significantly reduced the number of deaths due to asthma. However, when the disease is poorly controlled, for example due to ubiquitous exposure to airborne fungal conidia, this chronic inflammatory disease often results in lung dysfunction caused by airway architectural changes. The role of B lymphocytes in allergic asthma has been relegated to the production of IgE with relatively little being known about the trafficking of these cells in the tissues or their role(s) in the affected tissue. As a first step in ascertaining their function, the initial aim of this project was to characterize the recruitment and localization of B cells in the murine lung in response to Aspergillus fumigatus inhalation. We found that CD19+CD23+ B2 lymphocytes were recruited to the lungs after fungal inhalation and that IgA-, IgE-, IgG-producing cells localized around the large airways. The second aim of the project was to begin defining the impact that these B lymphocytes have on the allergic lung. By using mice that were deficient of conventional B cells, we were able to demonstrate that the allergic phenotype was retained, although the impact of tissue B1 B cells cannot yet be ruled out. We then investigated the ability of hyaluronic acid (HA), a major component of the extracellular matrix (ECM) generated at sites of chronic inflammation, to recruit and modulate B lymphocyte functions in allergic fungal disease. We found that B lymphocytes undergo chemotaxis in response to LMM HA, while HMM HA had little to no effect on B cell chemotaxis. Furthermore, HA-mediated B lymphocyte chemotaxis was significantly inhibited by blocking the CD44 HA receptor. We also demonstrated that LMM HA fragments elicit the production of the pro-fibrotic cytokines IL-10 and TGF-β1 by B lymphocytes. These observations suggest a previously unrecognized role for B lymphocytes and HA in the context of allergy and represent novel pathways by which B lymphocytes may contribute to airway inflammation and airway remodeling.