Recently much attention is given to lanthanides and their complexes as excellent catalysts for cleavage of nucleic acids. The thesis has been focused on the cleavage of plasmid and bacterial DNA by ions Nd3+ and Y3+ and by different carriers containing the lanthanide compounds. The creation of single-stranded nicks and double-stranded ones in the plasmid DNA molecules was studied by agarose gel electrophoresis. Verification of the cleavage of bacterial DNA was made by polymerase chain reaction using primers specific for the domain Bacteria and genus and species-specific primers. The results will be used in the development of the method that will allow perfect carriers`s coverage verification with the magnetic perovskit nucleus and other carriers with the lanthanide compounds.

Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal.

The role that norepinephrine plays in regulating the concentration of different proteins in the parietal cortex, hippocampus and cerebellum was assessed by investigating the effects of either a bilateral lesion of the locus coeruleus or neonatal administration of 6-hydroxydopamine. Two weeks after lesioning the locus coeruleus, the concentration of two different proteins was elevated in the hippocampus; a third protein was reduced in concentration in this brain area as a result of the lesion. Three proteins were affected in concentration in the cerebellum after the locus coeruleus lesion - two were elevated in concentration and one was reduced in concentration. No proteins were altered in concentration in the parietal cortex as a result of the lesion. Seventy days after neonatal treatment with 6-hydroxydopamine, a total of 6 proteins were found to be changed. Four of these (one in the hippocampus and 3 in the parietal cortex) were reduced in concentration while two proteins (both in the cerebellum) were elevated in concentration after neonatal treatment with the catecholamine neurotoxin. There was little overlap between those proteins affected in concentration by the bilateral lesion of the locus coeruleus and those changed by neonatal treatment with 6-hydroxydopamine. These results suggest that the concentration of a number of different proteins may, under normal physiological conditions, be regulated in vivo by norepinephrine in the brain.

Characterization of phosphoproteins-including detection, identification of phosphoproteins and identification of phosphorylation sites-is mostly done with radiolabeling and proteomic techniques. Three main topics related to phosphoprotein characterization are included in this dissertation. First, large-scale characterization of the CHO (Chinese hamster ovary) cell phosphoproteome was done using two dimensional gel electrophoresis (2DE) separation, visualization of phosphoproteins by radiolabeling or a phosphoprotein specific dye, followed by MALDI-TOF identification. Because radiolabeling of phosphoproteins is very sensitive and straightforward to quantify, such analysis can give a clear picture of the relative phosphosphorylation of proteins present in a sample. But there are also limitations to this approach, such as the inability of 2DE to separate hydrophobic, acidic and large proteins and the poor detection limits of common protein stains such as Coomassie stain. Additionally, it is difficulty to excise the right spots for identification because of the low abundance of phosphoproteins which have been visualized by radiolabeling. Furthermore, there are problems associated with metabolic radiolabeling. A second topic of the dissertation is the development of a novel strong cation exchange monolithic column for MudPIT (multidimensional protein identification technology) and phosphopeptide isolation. This column, a poly(AMPS-co-PEGDA) monolith containing as high as 40% AMPS, has several favorable features, such as high binding capacity, extraordinarily high resolution, and high peak capacity, making it ideal for resolving complex peptide samples. Application of this novel column to isolate model phosphopeptides was shown. More general use of this column in MudPIT (strong cation exchange column followed by reverse-phased MS/MS) is probably somewhat limited, due to the hydrophobicity of the AMPS monomer. A better monolith could be obtained if a more hydrophilic monomer was used. In the third area of the dissertation, several individual protein phosphorylation sites were analyzed, employing different strategies. Phosphorylation sites of one multiply phosphorylated tryptic peptide from CK2-phosphorylated phosducin-like protein (PhLP) was well characterized using enrichment with a MonoTip® TiO Pipette Tip. Analysis of syntaxin 1a phosphorylation by AMPK (AMP-activated protein kinase) was done by peptide level mapping for potential phosphopeptides after its unsuccessful trial with enrichment using the MonoTip® TiO Pipette Tip. Several criteria such as existence of non-phosphorylated forms of potential phosphopeptides, controls and reasonable retention times were used to rule out false positives. Phosphorylation of syntaxin 1a by AMPK was narrowed down to tryptic peptide T32 with evidence from different sources. Three phosphorylation sites of syntaxin 4 by AMPK were identified within the same peptide (Q65QVTILATPLPEESMK80). Further pinpointing of phosphorylation site(s) for syntaxin 1a by AMPK and further confirmation of these phosphorylation sites in syntaxin 4 by AMPK are required in vivo. The role of phosphorylation in syntaxin 4 by AMPK is the next step toward elucidation of AMPK activation and regulation of the glucose uptake mechanism.

Alopecia areata (AA) is a putative autoimmune hair loss disorder. It mainly affects the scalp hair but can also involve body hair, and can also affect the nail and the eye. While there are may be several lines of evidence to support the autoimmune basis of AA, there is still very little information on the hair follicle autoantigen(s) involved in its pathogenesis. In this project, serum antibodies (AA=10, control=10) were used to immunoprecipitate AA-relevant target antigens from normal human scalp hair follicle extracts. These immunoprecipitates were analysed by LC-MALDI-TOF/TOF mass spectrometry for target protein identification. This part of the project involved substantial methods development. Trichohyalin was immunoprecipitated by all AA sera, but by only 5 normal sera. Importantly, the mean Mascot scores of the AA group was significantly higher than the normal group (p=0.005). Keratin 16 was also identified from immunoprecipitates as another potential AA-relevant target antigen. Functional studies by ex vivo whole hair follicle organ culture using commercial antibodies to trichohyalin and keratin 16 significantly inhibited hair fibre elongation compared to controls. Indirect immunofluorescence studies revealed that AA sera contained higher immunoreactivity against normal human scalp anagen hair follicles compared to normal sera. Immunoreactivities were mainly in the outer root sheath and inner root sheath, and less so to the medulla and hair bulb matrix. Double immunofluorescence studies of AA and normal serum with anti-trichohyalin antibody (AE15) revealed co-localisation of 9 of the AA sera antibodies with trichohyalin in the inner root sheath (mostly in Henle¿s, less in Huxley¿s/inner root sheath cuticle), but only weakly in 3 normal sera. This study supports the involvement of an antibody response to anagen-specific hair follicles antigens in AA. Moreover, there may be some evidence that these antibodies may have a pathogenic role.

<p> The distribution of manganese in blood serum and erythrocytes has been investigated using a combination of radioactive tracer method with both gel chromatography and disc gel electrophoresis. </p> <p> In serum, there are two manganese-binding proteins. The first is a(beta)1 globulin with a molecular weight of 70,000. This forms a relatively labile manganese complex both in vitro and in vivo, and is remarkably similar in both its chromatographic and electrophoretic behaviour to the iron-binding protein, transferrin. The second protein is a higher molecular weight (beta) globulin. It is found to incorporate radiomanganese in vivo only, thereupon forming a very stable entity. </p> <p> In erythrocytes, manganese occurs predominantly in a porphyrin bound to apoglobin, giving rise to a species similar to hemoglobin . </p> / Thesis / Doctor of Philosophy (PhD)

No description available.

Alopecia areata (AA) is a putative autoimmune hair loss disorder. It mainly affects the scalp hair but can also involve body hair, and can also affect the nail and the eye. While there are may be several lines of evidence to support the autoimmune basis of AA, there is still very little information on the hair follicle autoantigen(s) involved in its pathogenesis. In this project, serum antibodies (AA=10, control=10) were used to immunoprecipitate AA-relevant target antigens from normal human scalp hair follicle extracts. These immunoprecipitates were analysed by LC-MALDI-TOF/TOF mass spectrometry for target protein identification. This part of the project involved substantial methods development. Trichohyalin was immunoprecipitated by all AA sera, but by only 5 normal sera. Importantly, the mean Mascot scores of the AA group was significantly higher than the normal group (p=0.005). Keratin 16 was also identified from immunoprecipitates as another potential AA-relevant target antigen. Functional studies by ex vivo whole hair follicle organ culture using commercial antibodies to trichohyalin and keratin 16 significantly inhibited hair fibre elongation compared to controls. Indirect immunofluorescence studies revealed that AA sera contained higher immunoreactivity against normal human scalp anagen hair follicles compared to normal sera. Immunoreactivities were mainly in the outer root sheath and inner root sheath, and less so to the medulla and hair bulb matrix. Double immunofluorescence studies of AA and normal serum with anti-trichohyalin antibody (AE15) revealed co-localisation of 9 of the AA sera antibodies with trichohyalin in the inner root sheath (mostly in Henle's, less in Huxley's/inner root sheath cuticle), but only weakly in 3 normal sera. This study supports the involvement of an antibody response to anagen-specific hair follicles antigens in AA. Moreover, there may be some evidence that these antibodies may have a pathogenic role.

The main focus of the PhD study was to develop new gel electrophoresis and ICP-MS based methods to analyze a wide variety of the bio-molecules such as proteins, phosphoproteins and metalloproteins etc. The tricine-sodium dodecyl sulfate-polyacrylamide gel electrophoresis (tricine-SDS-PAGE) method is commonly used to resolve low molecular mass proteins, however, it requires a high percentage gel and a very complicated procedure to achieve this separation. This study describes a modification to tricine-SDS-PAGE to make it more effective for the separation of smaller proteins and for coupling to ICP-MS. The modified method employs low percentage PAGE gels and low reagent concentrations that provide efficient separations, good quantitation and low matrix levels that are compatible with ICP-MS. This modified method was applied to analyze phosphopeptides. Phosphopeptides are very small in size and difficult to separate using the other techniques such as Laemmli SDS-PAGE, original tricine-SDS-PAGE, immobilized metal affinity chromatography (IMAC), size exclusion chromatography (SEC) etc. In this study a simplified procedure is described based on modifying the original tricine-SDS-PAGE method. A comparative study showed that this modified method successfully resolved a digest mixture of very low to high molecular mass phosphopeptides/peptides. In off-line coupling of this method with ICP-MS, much better recoveries of the peptides from the gel were obtained as compared to traditional methods which indicate the compatibility of this modified method for quantitative studies. An on-line coupling of the modified system with ICP-MS was also demonstrated and it was applied for the separation, detection and quantification of phosphopeptides. Another application of this modified system was the separation of serum proteins. Blood serum contains five major protein groups i.e., albumin, alpha-1 globulin, alpha-2 globulin, beta globulin and gamma globulin. The separation of these five major proteins in a single gel is difficult to achieve using traditional methods. The modified system was shown to be superior for the separation of these serum proteins in a 7% (m/v) native-PAGE gel and a cellulose acetate membrane. A further study was carried out into controlling the factors that cause metal loss and protein fragmentation in SDS-PAGE. Using a reducing sample buffer, and heating to high temperatures (90-100ºC) in alkaline or acidic conditions may cause protein fragmentation and decrease the metal binding affinity. 70ºC was found suitable to prepare the sample at neutral, alkaline or acidic pH as no fragmentation observed. To prevent metal loss, the binding constant (log K) values of metal-amino acids, play the major role. Those metals which have high binding affinities with the amino acids in proteins can also be affected by the variation of the pH so prior information about pH to maintain the binding constant values is essential to minimize metal loss. This was observed in the loss of zinc, and to a lesser extent copper from human serum albumin (HSA) as measured by inductively coupled plasma mass spectrometry (ICP-MS). The method described above was applied for the separation and quantification of the serum proteins obtained from age-related macular degeneration (AMD) patients (where the AMD patients were from Moorfields Eye Hospital, London). Zn and Cu were quantified employing external calibration. Zn concentration showed variation whilst Cu did not show any significant variations in samples from AMD patients. A brief study of the interaction of cisplatin and oxaliplatin with HSA and transferrin was also performed. Cisplatin bound much faster than oxaliplatin with HSA. After 24 hours incubation, cisplatin showed a decrease in signal intensity which indicates that cisplatin binding decreases with time. Cisplatin binding with transferrin as compared to HSA was not significant, which could be the result of unstable Pt-transferrin complex formation. Oxaliplatin did not show high binding to either protein, perhaps due to the presence of the bulky, non polar DACH ligand.

Mémoire numérisé par la Division de la gestion de documents et des archives de l'Université de Montréal.