Thesis (Ph. D.)--Case Western Reserve University, 2006. / [School of Medicine] Department of Molecular Biology and Microbiology. Includes bibliographical references. Available online via OhioLINK's ETD Center.

Thesis (Ph.D. in Molecular Biology) -- University of Colorado, 2005. / Typescript. Includes bibliographical references (leaves 100-113). Free to UCDHSC affiliates. Online version available via ProQuest Digital Dissertations;

Thesis (Ph. D.)--University of Missouri--Columbia, 2005. / "July 2005." Typescript. Vita. Includes bibliographical references (leaves 196-211). Also issued on the Internet.

Thesis (Ph. D.)--University of Florida, 2004. / Typescript. Title from title page of source document. Document formatted into pages; contains 258 pages. Includes vita. Includes bibliographical references.

Thesis (Ph. D.)--University of Washington, 2006. / Vita. Includes bibliographical references (leaves 132-145).

No description available.

Neste trabalho relata-se pela primeira vez a determinação de adenosina por um biossensor baseado em tirosinase. O biossensor foi desenvolvido mediante a modificação de um eletrodo de carbono impresso (SPE) com nanopartículas de ouro (AuNPs), tirosinase (Tyr) e Nafion, denominado biossensor Nafion/Tyr/AuNPs/SPE. As AuNPs sintetizadas possuem diâmetro médio de 15,0 ± 1,1 nm e sua função é melhorar a via de condução de elétrons entre a enzima e o eletrodo. Utilizou-se o aprisionamento com filme Nafion® para evitar a lixiviação enzimática da superfície do eletrodo. A tirosinase imobilizada apresentou boa atividade frente ao substrato catecol. Verificou-se que a adenosina atua como um inibidor do tipo não-competitivo. O biossensor é estável durante pelo menos 45 dias. Além disso, foi realizada a eletro-oxidação da adenosina para sua determinação. O biossensor apresenta sensibilidade superior em comparação com SPE, AuNPs/SPE e Nafion/AuNPs/SPE. As curvas de calibração revelaram duas faixas lineares para as concentrações de adenosina, de 1,0 × 10-5 mol L-1 até 5,0 × 10-5 mol L-1 e entre 6,0 × 10-5 mol L-1 e 1,2 × 10-4 mol L -1. O limite de detecção (3 × (desvio padrão + média dos brancos)/coeficiente angular da curva) foi de 7,0 × 10-7 mol L-1. / In this work we report for the first time the determination of adenosine by a biosensor based on tyrosinase. The biosensor was developed by modifying a screen-printed carbon electrode (SPE) with gold nanoparticles (AuNPs), tyrosinase (Tyr) and Nafion, denoted as Nafion/Tyr/AuNPs/SPE biosensor. The synthesized AuNPs have a mean diameter of 15.0 ± 1.1 nm and their function is to improve the electron conduction pathway between the enzyme and the electrode. The entrapment with Nafion® film was selected to prevent the enzyme lixiviation from the electrode surface. Immobilized tyrosinase showed good activity with the catechol substrate. It was found that adenosine acts as a non-competitive type inhibitor. The biosensor is stable for at least 45 days. In addition, the electro-oxidation of adenosine was performed for its determination. The biosensor has superior sensitivity compared to SPE, AuNPs/SPE and Nafion/AuNPs/SPE. Calibration curves revealed two linear ranges for adenosine concentrations of 1,010-5 mol L-1 up to 5,010-5 mol L-1 and from 6,010-5 mol L-1 to 1,210-4 mol L-1. The detection limit (3 × (standard deviation + mean of blanks)/slope of the curve) was 7,010-7 mol L-1.

The aim of the thesis was evaluation of various metabolic characteristics in the fruit flies Drosophila melanogaster with deficiency of adipokinetic hormone (AKH) production, and with adenosine receptor dysfunction. The experiments were done with a goal to evaluate involment of AKH and adenosine into control of the metabolic pathways. For that measuring of basic nutrients, level of Drome-AKH, mortality and some others characteristics in the fruit flies during starvation were performed. Results revealed the effect of AKH on metabolism of storage nutrients, however, the role of adenosine was unclear.

The human erythrocyte glucose transport protein (GLUT1) interacts with, and is regulated by, cytosolic ATP. This study asks the following questions concerning ATP modulation of GLUT1 mediated sugar transport. 1) Which region(s) of GLUT1 form the adenine nucleotide-binding domain? 2) What factors influence ATP modulation of sugar transport? 3) Is ATP interaction with GLUT1 sufficient for sugar transport regulation? The first question was addressed through peptide mapping, n-terminal sequencing, and alanine scanning mutagenesis of GLUT1 using [32P]-azidoATP, a photoactivatable ATP analog. We then used a combination of transport measurements and photolabeling strategies to examine how glycolytic intermediates, pH, and transporter oligomeric structure affect ATP regulation of sugar transport. Finally, GLUT1 was reconstituted into proteoliposomes to determine whether ATP is sufficient for the modulation of GLUT1 function in-vitro. This thesis presents data supporting the hypothesis that residues 332-335 contribute to the efficiency of adenine nucleotide binding to GLUT1. In addition, we show that AMP, acidification, and conversion of the transporter to its dimeric form antagonize ATP regulation of sugar transport. Finally, we present results that support the proposal that ATP interaction with GLUT1 is sufficient for transport modulation.

Magister Scientiae - MSc (Biotechnology) / Brassica napus is a plant that is used for human and animal consumption. This plant is also used for phytoremediation due to its relatively higher level of heavy metal tolerance. In South Africa, mining is one of the main drivers of the economy. One of the major negative environmental impacts of mining is heavy metal contamination. Soil metal content can rise to levels that are quite high and can even have a negative impact on the yields of B. napus crop. The glucosinolate-myrosinase system of B. napus is a system that is used as defence against biotic stressors. Indole glucosinolate breakdown products have been proven to enhance the antioxidant capacity of plants. Some have also shown growth promoting properties in plants. We studied the effect of exogenous DIM on B. napus and it role in Zr induced heavy metal stress. Germination percentages revealed that DIM increased germination, Zr application decreased germination and the DIMZr treatment reversed the negative impact of Zr application on B. napus. The effect of treatments on the biomass of B. napus was assessed by determining the dry weights. Results show that exogenous DIM improves biomass. Zr application decreased biomass and DIM-Zr treatment ameliorated the effect of Zr application. / 2020-08-31