Thesis (doctoral)--Universität Hamburg, 1985. / Includes bibliographical references (p. 172-184).

Diss. Linköping : Linköpings universitet, 2006.

Thesis (Doktor med.)--Medizinische Akademie, Dusseldorf, 1938.

Inaug. Diss.--Frankfurt am Main.

Inaug. Diss.--Frankfurt am Main.

Submitted by Alice Araujo (alice.caraujo@ufpe.br) on 2018-04-11T19:46:01Z No. of bitstreams: 1 DISSERTAÇÃO Luciana Dantas dos Santos.pdf: 7091828 bytes, checksum: 681c226589c8563abfe18add3c99d35d (MD5) / Made available in DSpace on 2018-04-11T19:46:01Z (GMT). No. of bitstreams: 1 DISSERTAÇÃO Luciana Dantas dos Santos.pdf: 7091828 bytes, checksum: 681c226589c8563abfe18add3c99d35d (MD5) Previous issue date: 2016-05-31 / A pesquisa foi realizada no estuário do Rio Formoso/ PE (08°39’S/35°10’W) e objetivou compreender a dinâmica sazonal dos processos sedimentológicos e geoquímicos no estuário. Foram coletadas 48 amostras de sedimentos superficiais em setembro/2014 e março/2015, compreendendo o período chuvoso e seco, respectivamente. Foram realizadas análises de granulometria, de matéria orgânica total (MOT), de carbono orgânico total (COT), de fósforo (Total, Orgânico e Inorgânico), carbonato de cálcio (CaCO3) e calculada a razão elementar C/P. Como análise complementar foram realizadas as análises da fração arenosa e da morfoscopia com intuito de identificar as características físicas sedimentares. Foram executadas também análises de correlação (Spearman), de componentes principais e agrupamento (Cluster). Foram encontrados sedimentos que variaram de areia grossa a silte fino, com um predomínio da granulação areia. A fração cascalho teve pouca participação no total das amostras e a maior proporção da fração de lama ocorreu a montante do estuário. Com relação ao grau de seleção, houve um predomínio de sedimentos pobremente a muito pobremente selecionadas. Já para a razão C/P, foram observados valores dominantes acima de 300, indicando origem continental da matéria orgânica. Na sazonalidade, houve um aumento dos parâmetros de granulação, grau de seleção e COT, e uma diminuição dos parâmetros CaCO3, MOT, fósforo (total, orgânico e inorgânico) na passagem do período chuvoso/2014 para o seco/2015. As análises de correlação indicaram significância entre os teores dos parâmetros geoquímicos com o percentual de lama, com exceção do CaCO3. Comportamento anômalo foi encontrado para o estudo na amostra localizada próximo a tanques de carcinicultura. / The study was conducted in the Formoso River estuary–PE (08°39’S/35°10’W) and this research aimed to understand the seasonal sedimentary dynamics and geochemical processes in the estuary. Forty-eight sediment samples were collected in September/2014 and March/2015, comprising the rainy and dry season, respectively. Analyses of grain size, total organic matter (TOM), total organic carbon (TOC), phosphorus (TP, OP, IP), CaCO3 and C/P elemental ratio. Coarse fraction analysis and morphoscopy were performed aiming to identify sedimentary physical characteristics. The data was treated by mean of the correlation Spearman analysis, principal components analysis (PCA) and Cluster Analysis. The sediment grain-size found ranged from coarse sand to fine silt, with a prevalence of sands. Few samples presented gravel percentages and the highest mud contents were observed in the upper estuary for both periods. With regard of sorting, there was a predominance of poorly to very poorly sorted sediments. As for the C/P ratio, were observed dominant values higher than 300, indicating continental origin of organic matter. Regarding the seasonality, there was an increase of grain size, sorting and TOC, and a decrease of CaCO3, TOM, phosphorus (total, organic and inorganic) in the transition from the 2014 rainy season to 2015 dry period. Correlation analysis showed significance between geochemical parameters and the mud content, except for the CaCO3. Anomalous behavior was observed in the sample located near the shrimp farming ponds.

No description available.

No description available.

Adenine deaminase (ADE) catalyzes the conversion of adenine to hypoxanthine. Mechanistic characterization of ADE from Escherichia coli was performed along with biophysical studies. The structure of ADE was solved from A. tumefaciens. The structure, along with the biochemical and biophysical characterization, enabled the elucidation of the mechanism of the deaminase reaction of ADE. Elucidation of the origin of the oxygenation reactions within ADE led to the discovery of a promiscuous catalase reaction. The diiron ADE from all tested bacterial species exhibited this unusual reaction, along with the generation of superoxide and hydroxyl radicals, the latter being responsible for the oxygenation of the protein. The residues that were identified to be oxygenated were primarily the metal binding residues implying the origin of this reaction was the binuclear iron center. A group of bacterial enzymes that are co-localized in the same genomic operon as ADE but of unknown function were identified. The enzyme Bh0637 from Bacillus halodurans, a representative member of this group of enzymes was characterized. This enzyme was shown to preferentially catalyze the deamination of epigenetic base, N-6-methyadenine. Lastly, gram-negative bacteria have a highly conserved phn operon composed of 14 genes to break the C-P bond of inert alkylphosphonates. The genes phnGHIJKLM are absolutely critical for this activity. We discovered that methylphosphonate reacts first with MgATP to form alpha-D-ribose-1-methylphosphonate-5-triphosphate (RPnTP) and adenine by the action of PhnI, PhnG, PhnH and PhnL. PhnI by itself was shown to perform a novel nucleosidase reaction converting MgATP to ribose-5-triphosphate and adenine. The triphosphate moiety of RPnTP is then hydrolyzed to pyrophosphate and alpha-D-ribose-1-methylphosphonate-5-phosphate (PRPn) by PhnM. The carbon-phosphorus bond of PRPn is subsequently cleaved via a radical-based reaction to alpha-D-ribose-1,2-cyclic-phosphate-5-phosphate (PRcP) and methane in the presence of S-adenosyl-L-methionine by PhnJ.

No description available.