Research on natural environments, over the last decade, is replete with microbial diversity studies that used culture-independent approaches. The cloning and sequencing of the 16S rRNA genes has been the driving force in the expansion of awareness about the great diversity of previously undiscovered microorganisms. Well-known uncultured groups of microorganisms are numerous, and half of the known phylogenetic divisions of bacteria are not represented in any culture collection. It is no longer assumed that cultures acquired from an environment represent the dominant or physiologically important organisms from that environment. A high throughput culturing (HTC) technique was developed in an attempt to bring into culture some of these widespread and uncultured microorganisms. Over the course of 3 years, 2,484 culturing attempts were screened for microbial growth from sample collections off the coast of Oregon and 576 attempts from groundwater at McClellan Air Force Base (MAFB). However, using the HTC approach up to 14% of the microorganisms counted by direct microscopy were cultured. In contrast, less than 1% of the microorganisms from natural environments that are observed under a microscope can be grown using standard agar plating techniques. This newly developed technique was successful at bringing into culture 11 previously uncultured or undescribed Proteobacteria. Four were isolated from the marine environment including, members of the SAR11 clade (alpha subclass), OM43 (beta-subclass), SAR92 (gamma subclass), and OM60/OM241 (gamma subclass). SAR11 was transiently cultured in this study but was later successfully brought into culture using these HTC techniques by Mike Rapp��. Eight were isolated from a trichioroethene (TCE) and cis-dichloroethene (cis-DCE) contaminated aquifer, including members of the MHP14 clade (alpha subclass), 4-Org1-14 dade (alpha subclass), Herbaspirillum/Oxalobacter clade (beta subclass), HTCC333 (beta subclass), HTCC410 (beta subclass), PM1 clade (beta subclass), Boom-7m-04 clade (beta subclass) and OM43 clade (beta subclass). Culturing microorganisms is an important step towards understanding their physiology and ecology, and in most cases is necessary for the formal systematic description of a new species. For microorganisms of global significance, such as the major uncultured bacterioplankton and soil microbiota, obtaining cultures is a prerequisite for obtaining complete genome sequences and understanding the relevance of these microorganisms to biogeochemical cycles. / Graduation date: 2003

Call number: LD2668 .T4 1979 F47 / Master of Science

M.Tech. (Food Technology) / Coeliac disease is an autoimmune disease triggered by the ingestion of gluten; persons suffering from coeliac disease are compelled to follow a life-long gluten-free diet. Gluten-free bread, (GFB), has poor quality attributes compared to wheat bread. The effect of mageu, a traditional beverage on quality parameters of GFB with and without selected hydrocolloids was studied. Mageu produced from maize flour and commercial starter cultures were used in GFB based on sorghum, soybean flour and maize starch. It is hypothesized that mageu with or without hydrocolloids could improve GFB quality aspects. The quality parameters measured were specific volume, loaf height, bake loss, rheological attributes, crumb firmness, firming rate, onset of mould growth and sensory attributes: texture, crumb colour, crust colour, flavour and overall acceptability.....

No description available.

No description available.

The study of the aging process is the investigation as to how the passage of time affects cells, organs, and organisms. Aging is a very complex and incompletely understood phenomenon. This is reflected by the number of theories attributing aging to a variety of causative factors such as: (1) the somatic mutations occurring spontaneously or produced by ionizing radiation, which are thought to have some effect on again but are not responsible for the normal process; (2) the alteration of macromolecules as the cells of an organism age forming neoantigens and functioning in the autoimmune reactions; the Cross-linkage theory which maintains that large molecules necessary for life processes, such as deoxyribonucleic acid (DNA) and collagen are progressively immobilized in all cells and tissues by cross-linkage. Aging has also been studied in relation to the self-destructive “programmed death” characteristic of some parts of embryological development. Moreover, senescent changes involve different kinds of cells and tissues in the organism and therefore various mechanisms must occur. For example, the aging of postmitotic cells, such as neurons and cardiac cells probably proceeds by a different mechanism than the proliferating tissues, such as the skin, the gut lining, and the blood forming elements. It is apparent that there is probably no single aging process, but a series of aging processes which natural selection would tend to synchronize even if the causes were physiologically independent.

Master of Science

Este trabalho apresenta um estudo empregando duas técnicas óticas para monitorar o crescimento de culturas de cepas de Escherichia coli em dois meios de cultura líquidos: Espectroscopia de absorção UV-Vis (turbidimetria) e espectroscopia Raman. Na primeira técnica, a turbidez permite avaliar as diferentes fases naturais de crescimento de uma cultura bacteriana (lag, exponencial, estacionária e decaimento) por meio da densidade ótica, medida com um espectrômetro UV-VIS. Na segunda, o espalhamento Raman (medido com um espectrômetro dispersivo), a partir de amostras de água contaminada, fornece não apenas informações sobre as fases de crescimento, mas também abre a possibilidade de identificação bacteriana através da sua impressão digital característica. Mediu-se a dinâmica de duas cepas de E. coli – (nomeadas como H2/11 e H3C2/12) em um caldo líquido nutriente e quatro cepas de E. coli (nomeadas como H2/11, H3C2/12, 109 e 110) em caldo líquido EC, mantidas a 37,0°C ao longo de 24 horas. Alíquotas das amostras foram removidas da cultura em intervalos de tempo regulares para medições espectrais. A análise da turbidez permitiu medir o tempo de geração (isto é, o tempo de duplicação de uma população), que foi maior para cepas crescidas em caldo EC. Os espectros Raman forneceram informações sobre a evolução temporal das bandas a 942 cm-1, 977 cm-1, 1036 cm-1, 1086 cm-1, 1140 cm-1, 1188 cm-1, 1182 cm-1, 1207 cm-1 e 1251 cm-1, associadas com impressões digitais de componentes biológicos específicos. Os dados espectrais foram analisados por Análise de Componentes Principais (PCA). Os resultados obtidos em ambas as técnicas permitiram identificar as fases lag, exponencial e estacionária das cepas estudadas. / This work is a study using two optical techniques to monitor the growth of cultures of Escherichia coli strains in two liquid culture medium: Raman spectroscopy and UV-Vis absorption spectroscopy (turbidimetry). In one hand, turbidity allows evaluating the different phases of growth of a bacterial culture (lag, exponential, stationary and decay) by optical density, measured with an UV-VIS spectrometer. On the other hand, Raman scattering (measured with a dispersive spectrometer) from contaminated water samples not only provides information about the grow phases, but also opens a possible identification of bacterial by its characteristic fingerprint. Two strains of E. coli (named as H2 / 11 and H3C2 / 12) were measured in liquid nutrient broth and four E. coli strains (named H2 / 11, H3C2 / 12, 109 and 110) in EC liquid broth, kept at 37.0 ° C over 24 hours. Aliquots of the samples were removed from the culture at regular time intervals for spectral measurements. The turbidity analysis allowed to measure the generation time, which was higher for strains grown in EC broth. Raman spectra provided information about the time evolution of the bands at 942 cm-1, 977 cm-1, 1036 cm-1, 1086 cm-1, 1140 cm-1, 1188 cm-1, 1182 cm-1, 1207 cm-1 e 1251 cm-1, associated with fingerprints of biological components. Data were analyzed by Principal Component Analysis (PCA). These results of both techniques allowed identifying the phases lag, exponential and stationary of the studied strains.

Este trabalho apresenta um estudo empregando duas técnicas óticas para monitorar o crescimento de culturas de cepas de Escherichia coli em dois meios de cultura líquidos: Espectroscopia de absorção UV-Vis (turbidimetria) e espectroscopia Raman. Na primeira técnica, a turbidez permite avaliar as diferentes fases naturais de crescimento de uma cultura bacteriana (lag, exponencial, estacionária e decaimento) por meio da densidade ótica, medida com um espectrômetro UV-VIS. Na segunda, o espalhamento Raman (medido com um espectrômetro dispersivo), a partir de amostras de água contaminada, fornece não apenas informações sobre as fases de crescimento, mas também abre a possibilidade de identificação bacteriana através da sua impressão digital característica. Mediu-se a dinâmica de duas cepas de E. coli – (nomeadas como H2/11 e H3C2/12) em um caldo líquido nutriente e quatro cepas de E. coli (nomeadas como H2/11, H3C2/12, 109 e 110) em caldo líquido EC, mantidas a 37,0°C ao longo de 24 horas. Alíquotas das amostras foram removidas da cultura em intervalos de tempo regulares para medições espectrais. A análise da turbidez permitiu medir o tempo de geração (isto é, o tempo de duplicação de uma população), que foi maior para cepas crescidas em caldo EC. Os espectros Raman forneceram informações sobre a evolução temporal das bandas a 942 cm-1, 977 cm-1, 1036 cm-1, 1086 cm-1, 1140 cm-1, 1188 cm-1, 1182 cm-1, 1207 cm-1 e 1251 cm-1, associadas com impressões digitais de componentes biológicos específicos. Os dados espectrais foram analisados por Análise de Componentes Principais (PCA). Os resultados obtidos em ambas as técnicas permitiram identificar as fases lag, exponencial e estacionária das cepas estudadas. / This work is a study using two optical techniques to monitor the growth of cultures of Escherichia coli strains in two liquid culture medium: Raman spectroscopy and UV-Vis absorption spectroscopy (turbidimetry). In one hand, turbidity allows evaluating the different phases of growth of a bacterial culture (lag, exponential, stationary and decay) by optical density, measured with an UV-VIS spectrometer. On the other hand, Raman scattering (measured with a dispersive spectrometer) from contaminated water samples not only provides information about the grow phases, but also opens a possible identification of bacterial by its characteristic fingerprint. Two strains of E. coli (named as H2 / 11 and H3C2 / 12) were measured in liquid nutrient broth and four E. coli strains (named H2 / 11, H3C2 / 12, 109 and 110) in EC liquid broth, kept at 37.0 ° C over 24 hours. Aliquots of the samples were removed from the culture at regular time intervals for spectral measurements. The turbidity analysis allowed to measure the generation time, which was higher for strains grown in EC broth. Raman spectra provided information about the time evolution of the bands at 942 cm-1, 977 cm-1, 1036 cm-1, 1086 cm-1, 1140 cm-1, 1188 cm-1, 1182 cm-1, 1207 cm-1 e 1251 cm-1, associated with fingerprints of biological components. Data were analyzed by Principal Component Analysis (PCA). These results of both techniques allowed identifying the phases lag, exponential and stationary of the studied strains.