In this study, electrophoretic mobilities of native and two types of trypsin digested sarcoplasmic reticulum vesicles have been determined by microelectrophoresis using a Doppler Electrophoretic Light Scattering Analyzer to investigate the influence of hydrodynamic drag, caused by the Ca2+, Mg2+ -ATPase protruding from the surface of native sarcoplasmic reticulum vesicles. After the prolonged digestion (protein:trypsin ratio of 20 for 3 hours at 25°C), the ATPase was cleaved and removed from the sarcoplasmic reticulum membrane as shown with SDS gel electrophoresis and an ATPase activity assay. Ionic strength and pH dependence of mobility showed a nearly pH independent increase in initial surface charge density after prolonged digestion. Adsorption isotherms for native, short (protein:trypsin ratio of 200 for 2 minutes at 25°C), and prolonged digested sarcoplasmic reticulum vesicles were recorded for TPhP+ (tetraphenylphosphonium), PCP- (pentachlorophenol), and Ca2+, and fitted to the Langmuir adsorption model. The most important result from the adsorption isotherms is that adsorption of the three ions did not increase significantly after prolonged digestion. From this it can be concluded that hydrodynamic drag does not have a measurable influence on electrophoretic mobility of sarcoplasmic reticulum vesicles and therefore cannot account for the big differences in mobility between sarcoplasmic reticulum vesicles and a comparable artificial membrane system (phosphatidylcholine/phosphatidylserine liposomes), which were observed in this lab earlier. A thermodynamic analysis of adsorption was done for PCP- adsorption to phosphatidylcholine liposomes, TPhP+ adsorption to phosphatidylcholine liposomes, and TPhP+ adsorption to sarcoplasmic reticulum vesicles, by recording adsorption isotherms at 10°C, 25°C, 40°C, and 55°C. The adsorption of PCP- to phosphatidylcholine liposomes was clearly driven by enthalpy. In contrast, the adsorption of TPhP+ to phosphatidylcholine liposomes and sarcoplasmic reticulum vesicles was characterized by a positive enthalpy and a still larger negative entropy term. The thermodynamic analysis of ion adsorption shows that the driving forces of adsorption are very similar for sarcoplasmic reticulum vesicles and the chosen artificial membrane system (phosphatidylcholine liposomes) in spite of the significant lower adsorption of biological membranes compared to artificial membrane systems.

Elucidation of the chemical speciation of trace metals in the natural aquatic environment will lead to a better understanding of their distribution and ecological effects. One approach which can provide useful information about the chemical reactivity of metal ions is the measurement of their activity. Phase equilibrium methods are required and liquid-liquid partition equilibria are applicable. This study utilized model systems to demonstrate this applicability. The partitioning of copper(II) ions as a chelate of acetylacetone was used to determine the trace activity coefficients of the copper(II) electrolyte in the CU(N03)2-HN03-KN03, Cu(N03)2-HCl04-NaCl04 and CuC12-HCl-KCl systems over a wide range of ionic strengths (u). By careful control of pH and acetylacetone concentration only 1-3% of the metal ion was extracted. Under these conditions the amount extracted is proportional to the activity. The concentration of the bis(Acetylacetonato) Copper(II) was determined in the organic phase by spectrophotometric and atomic absorption methods but any convenient concentration technique could be used to measure the amount extracted. A comparison of activity measurements by liquid-liquid partitioning was made with electrochemical measurements by utilizing a copper ion selective electrode. The significantly lower activity coefficient values obtained by the electrochemical method were explained in terms of the liquid junction potential and the necessity for extrathermodynamic approaches to single ion activities. Potential application of the liquid-liquid partitioning method to the determination of trace activity coefficients in natural aquatic systems was demonstrated by extension of the method to measurements in copper(II) amino acid solutions at u = 0.001 and u = 0.723. The ionic strength adjustments in this case were made with NaCl. A significant difference in the free copper (II) ion activity was observed between solutions of copper(II) glycinate and copper(II) alaninate under identical conditions of metal and ligand concentrations, pH and ionic strength. The copper(II) activity measurements made in the presence of the amino acids at u = 0.723 are not possible with copper ion selective electrodes due to chloride interference.

The compound 3-phenylindole (3PI) is a particularly active antimicrobial which interacts with phospholipids in fungal mycelia membranes, and which strongly inhibits the uptake of phosphate into fungal mycelia. The physical effects of 3PI on ion transport across bilayer lipid membranes composed of phosphatidylcholine/cholesterol have been investigated using three lipophilic ions and one ion/carrier complex. It was found that 3PI increased the electrical conductivity induced by the lipophilic cation (tetraphenylarsonium) and by the positively charged complex (nonactin-K('+)) by several orders of magnitude whereas 3PI decreased the conductivity induced by the two lipophilic anions (tetraphenylborate, dipicrylamine) by a factor of less than ten. These conductivity changes are explained as a combination of changes in the electrostatic and in the non-electrostatic properties of the bilayer. The electrostatic potential of the bilayer interior was shown to decrease in the presence of 3PI, a phenomenon which was also confirmed by measurements of the surface potential of phosphatidylcholine/cholesterol monolayers. The changes in non-electrostatic properties of the bilayer are qualitatively discussed in terms of increased bilayer fluidity or decreased bilayer thickness brought about by the presence of 3PI. The partition coefficient of the lipophilic anions, as determined by the voltage-step transient current technique, decreased slightly when 3PI was present in the aqueous phase. From the voltage dependence of the normalized steady state conductivity it was shown that 3PI did not kinetically limit tetraphenylarsonium transport but that it did kinetically limit nonactin-K('+) transport at concentrations greater than 25 (mu)M 3PI. The theory of carrier-mediated transport predicts the occurrence of transient currents in the kinetically limited regime but no transients were detected for nonactin-K('+) in the presence of 80 (mu)M 3PI. A method for analyzing the adsorption of neutral lipophilic molecules onto lipid monolayers has been presented, and by this method it was found that the partition coefficient of 3PI onto phosphatidylcholine/cholesterol monolayers was 1.3 x 10('-4) m and that the maximum adsorbed surface number density of 3PI was 1.1 x 10('-6) moles/m('2). From the experimental changes in monolayer surface potential as a function of adsorbed surface number density, a value for the normal component of the dipole moment of 3PI was obtained.

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Lutetium 177 ions were implanted in iron and nickel foils using a mass separator. The rotations of the angular correlation pattern caused by the hyperfine fields acting on the implanted nuclei were measured for the 71-250 keV and the 208-113 keV cascades in the beta-decay product Hafnium 177. Using measured data, the g-factor for the 250 keV spin 11/2, second excited state in Hf177 was determined, as were the internal fields acting on the Hf177 impurity in iron and nickel. The results are as follows: g11/2 = 0.277 ± 0.080 HFe(int) = -133 ± 7 k0e HNi(int) = -58.6 ± 8 k0e / Thesis / Master of Science (MSc)

In this thesis, the process involved in the precipitations and separations of the metal of Group II and Group III studied. Suggestions have also been offered whereby students can make an analysis without loosing metals in the initial precepitation.

One of the intriguing features of biological systems is the prevalence of highly selective and often very strong interactions among different cellular components. Such interactions play a variety of organizational, mechanical, and physiological roles at the cellular and organism levels. Antigen-antibody complexes are representative examples of highly selective and potent interactions involving proteins. The marked specificity of protein-antibody complexes have led to a wide range of applications in cellular and molecular biology related research. They have become an integral research tool in the present genomic and proteomic era. Unfortunately, the production of selective tools based on antigen-antibody interactions requires cumbersome protocols. The long term goal of this project explores the possibility of manipulating liposomes to serve as the chemical receptors ("artificial antibodies") against selected proteins. Cellular lipids (e.g., lipid rafts) are known to facilitate highly selective binding of proteins on cell membranes. The binding of proteins to cell membranes can be envisaged to be modulated via interactions between polar (charged) and non-polar head groups of lipids and the complementary amino acid residues of proteins. Their interaction is facilitated by a combination of van der Waals, electrostatic, hydrogen bonding and hydrophobic forces. A further interesting aspect of the above interaction is the "fluidity" of the membrane resident lipids, which can migrate from other regions to further enhance the complementary interactions of proteins on the initially "docked" membrane surface. With these features in mind, the end goal of this project is expected to deliver lipid-based chemical receptors "synthetically" designed against proteins to function as "artificial antibodies". Protein sensing will be accomplished with lipid receptors assembled in templated polymerized liposomes. The research presented here specifically focus on the analytical aspects of protein sensing via polymerized liposome vesicles. Lanthanide ions (Eu(III) and Tb(III)) are incorporated into polymerized liposome with the expectation to "report" quantitative and qualitative information on the interacting protein. Our proposition is to extract quantitative and qualitative information from the luminescence intensity and the luminescence lifetime of the lanthanide ion, respectively. A thorough investigation is presented regarding the analytical potential of these two parameters for protein sensing. Two chemometic approaches - namely partial least squares (PLS-1) and artificial neural networks (ANN) - are compared towards quantitative and qualitative analysis of proteins in binary mixtures.