The first documented carbonatites in Manitoba occur as dykes and pods up to 15 meters in length and several meters in width at Eden Lake hosted in a post-orogenic syenitic complex within the Trans-Hudson Orogen. The carbonatites consist dominantly of calcite with lesser clinopyroxene, feldspar, apatite and titanite. Primary and xenocrystic clinopyroxene have distinct compositions, whereas xenocrystic feldspar has well-developed plagioclase and alanite rims. The whole-rock major- and trace-element composition of the carbonatite is consistent with global averages for calcio-carbonatites. Stable-isotope compositions of calcite indicate an igneous origin; the low δ13C ratios may reflect the influence of subducted sedimentary carbonate. A zircon age of 1815±8 Ma corresponds with the time of emplacement, whereas younger titanite ages reflect local thermal history. Although field relations suggest a genetic link to the host syenites, whole-rock geochemical data is incompatible with immiscibility or crystal fractionation models, suggesting a discrete mantle source for the carbonatite.

Intact strawberry fruit did not produce detectable t-2-H which is derived from -linolenic acid (18:3). However, in response to wounding by gentle bruising, strawberry fruit emitted t-2-H with the largest quantity produced within 10 min following injury. The level of total lipid 18:3 in the fruit increased two-fold in response to wounding whereas free 18:3 declined slightly (about 30%). At 10 min following wounding, fruit exhibited a 25% increase in 13-lipoxygenase (LOX) activity, which leads to the production of 13-hydroperoxyoctadecatrienoic acid (13-HPOT) from 18:3. The activity of hydroperoxide lyase (HPL), which catalyzes formation of cis-3-hexenal (c-3-H), the precursor of t-2-H, from 13-HPOT, increased two-fold at 10 min after wounding. Thus, within 15 min after wounding, free 18:3 substrate availability and the activity of two key enzymes, LOX and HPL, changed in a manner consistent with increased t-2-H biosynthesis. The site and mode of interaction of C6 aldehydes with Botrytis cinerea, a common pathogen of many plant species, was characterized using radiolabeled six carbon (C6) aldehydes, including c-3-H and t-2-H. An approximately 25% molar conversion of 18:3 to C6 aldehydes was obtained by enzymatic manipulation with LOX and HPL extracts. Following exposure of Botrytis cultures to radiolabeled aldehydes, radiolabeled aldehydes were recovered in protein fractions, but not in the lipid fraction. They were incorporated into conidia at a 20-fold higher level than mycelia (per mg fresh weight). About 95% of the radiolabeled aldehyde was recovered in proteins on the surface (wash protein) of the fungal tissue, while 5% was from protein in internal tissue (cell wall and membrane and cytosol). Supplementing radiolabeled aldehydes with nonradiolabled C6 aldehydes to increase the vapor phase concentration affected distribution of radiolabel in each protein fraction. The t-2-H at both 5.4 and 85.6 mol affected protein expression patterns, changing the intensity of expression in over one third of all proteins. Both up- and down-regulation of specific proteins were observed. Though five proteins of interest were analyzed, their identities were not determined. However, the data indicate a clear effect of t-2-H on protein expression in Botrytis cinerea.

The Luteinizing hormone receptor (LHR) belongs to the G protein-coupled receptor family, asdo the other glycoprotein hormone receptors for FSH, TSH, and CG. The LHR comprises twohalves of ~350 amino acids: an extracellular hormone binding exodomain and a seventransmembrane-spanning endodomain responsible for signal generation. Hormone binds to theexodomain with high affinity, and the resulting conformational changes in thehormone/exodomain complex modulate the endodomain to generate hormone signals. Hormonebinding to an LHR produces hormonal signals (cis-activation), but it is not known whether aliganded LHR could activate other unoccupied LHRs (trans-activation). The LHR activates bothadenylyl cyclase and phospholipase C??. This dissertation shows that trans-activation of the LHRleads to the activation of adenylyl cyclase to induce cAMP but not to the activation ofphospholipase C?? to induce the inositol phosphate signaling. Trans-activation offers amechanism of signal amplification at the receptor level and also provides a mechanism ofmultiple signal generation for a liganded LHR to cis-activate phospholipase C?? and transactivateadenylyl cyclase. Also coexpression of Gi2 with a constitutively activating LHR(Asp578Gly), the most common mutation of male-limited precocious puberty, shows that Gi2could completely inhibit cAMP induction by the LHR mutant. Experiments using the carboxylterminal region of G protein ?? subunits demonstrate that LHR has overlapping binding sites forG?? subunits Gs and Gi2.

The amino acid (2S, 4R)-4-hydroxyproline (Hyp) plays a critical role in animal kingdom as structural protein collagen. It is ubiquitous in plant cell walls performing various functions such as structural assembly, plant hormones, plant growth, defense against pathogens, etc. Glycosylation of Hyp is often seen in plant cell walls with L-Arabinofuranose and D-Galactopyranose and not in animal kingdom. Glycosylation is a post-translational modification, which affects characteristics of proteins and peptides. The main objective of this thesis is to synthesize various L-arabinofuranosylated hydroxyproline model amides and investigate their thermodynamic and kinetic properties of cis/trans amide isomerization. These results are compared with the previous research of D-galactopyranosylated hydroxyproline model amides, which may provide an insight to structural implications for their stability and conformations of peptides and specificity in plants. Both - and -L-arabinosylation of Hyp resulted in the stabilization of trans rotameric state at room temperature while the α-anomer leads to cis rotamer stabilization at higher temperature. Similarly, both unnatural 4S-hydroxyproline (hyp) building blocks resulted in stabilization of trans rotamer but α-anomer shows exo configuration instead of endo. This result shows a reverse trend when compared to galactosylated hydroxyproline building blocks as previous research results in our group. Our results may provide further insight to the role of glycosylation on protein structure and stability in plants.

Graduate / 0485

The first documented carbonatites in Manitoba occur as dykes and pods up to 15 meters in length and several meters in width at Eden Lake hosted in a post-orogenic syenitic complex within the Trans-Hudson Orogen. The carbonatites consist dominantly of calcite with lesser clinopyroxene, feldspar, apatite and titanite. Primary and xenocrystic clinopyroxene have distinct compositions, whereas xenocrystic feldspar has well-developed plagioclase and alanite rims. The whole-rock major- and trace-element composition of the carbonatite is consistent with global averages for calcio-carbonatites. Stable-isotope compositions of calcite indicate an igneous origin; the low δ13C ratios may reflect the influence of subducted sedimentary carbonate. A zircon age of 1815±8 Ma corresponds with the time of emplacement, whereas younger titanite ages reflect local thermal history. Although field relations suggest a genetic link to the host syenites, whole-rock geochemical data is incompatible with immiscibility or crystal fractionation models, suggesting a discrete mantle source for the carbonatite.

Graduate / 0485

Thèse (M.Sc.)--Université Laval, 2006. / Bibliogr.: f. 95-102. Publié aussi en version électronique.

Thesis (M.S.)--University of Tennessee Health Science Center, 2008. / Title from title page screen (viewed on July 31, 2008). Research advisor: Martha M Howe, Ph.D. Document formatted into pages (vii, 127 p. : ill.). Vita. Abstract. Includes bibliographical references (p. 103-116).

Thesis (Ph. D.)--University of Washington, 2004. / Vita. Includes bibliographical references (leaves 74-87).