Contains theses abstracts by students who chose a 1-year restricted period. http://hdl.handle.net/123456789/39 2013-04-28T06:27:50Z 2013-04-28T06:27:50Z Fontaine, Kyle Matthew http://hdl.handle.net/1993/18490 2013-04-09T15:05:26Z 2012-10-10T00:00:00Z

Title: An investigation of the symbiotic association between the sub-aquatic fungus Dermatocarpon luridum var. luridum and its green algal photobiont Authors: Fontaine, Kyle Matthew Abstract: The biology of the sub-aquatic lichen, Dermatocarpon luridum, was investigated. This lichen is sparsely distributed within the temperate climatic zones around the world, colonizing rock along watercourses that regularly experience water level fluctuations. Specimens collected from Canada and Austria were cultured using standard growth media. Brightfield microscopy was used for algal species identification, while fungal ITS, algal ITS and algal actin gene sequences were used for phylogenetic and population genetic evaluation. Results were: 1) axenic cultures of the photobiont were successful, while those of the mycobiont were not successful; 2) Diplosphaera chodatii is the photobiont associated with D. luridum var. luridum and allies, suggesting algal sharing between mycobiont species; 3) genetic diversity is high, and gene flow was high within local populations, but low between continental populations. Diplosphaera chodatii may be a keystone species contributing to the survival of D. luridum var. luridum along with other sub-aquatic, aquatic and terrestrial lichens.

2012-10-10T00:00:00Z Liu, Lingwei http://hdl.handle.net/1993/18313 2013-04-01T20:10:23Z 2013-04-01T00:00:00Z

Title: The role of gibberellin and abscisic acid in regulating preharvest sprouting in barley (Hordeum vulgare L.) Authors: Liu, Lingwei Abstract: Preharvest sprouting (PHS), the germination of seeds on the maternal plant before harvest, is a big challenge for barley producers worldwide. It is attributed mainly to low seed dormancy. The balance between two classical plant hormones, gibberellin (GA) and abscisic acid (ABA) regulates seed dormancy and germination, and the endogenous level of these two hormones in plants is determined by their biosynthesis and catabolism. This thesis characterized the expression patterns of the major GA and ABA metabolism genes in barley cv. Betzes during seed development, and germination in both dormant and non-dormant seeds. The results indicate that specific gene family members of the two hormones play distinct temporal roles in regulating seed development, dormancy onset and release, and germination. Since only two genes encoding the GA deactivating GA 2-oxidase enzyme have been known so far in barley, this study also identified two new GA2ox genes designated as HvGA2ox1 and HvGA2ox3.

2013-04-01T00:00:00Z Cardinal, Pascal http://hdl.handle.net/1993/17600 2013-03-20T17:19:12Z 2013-03-13T00:00:00Z

Title: Assessing nutrient and pharmaceutical removal efficiency from wastewater using shallow wetland treatment mesocosms Authors: Cardinal, Pascal Abstract: Wastewaters from rural sewage lagoons in Manitoba contain pharmaceuticals that are potentially harmful to non-target organisms and reduce overall water quality when released. An option for reducing exposure to wastewater contaminants and potential toxicity is surface flow treatment wetlands. However, little is known of the fate of pharmaceuticals in these types of systems. The fate and effects of six pharmaceuticals (carbamazepine, clofibric acid, fluoxetine, naproxen, sulfamethoxazole, sulfapyridine) were assessed in mesocosms simulating treatment wetlands in two separate 28-day experiments in the summer and fall of 2011, respectively: with and without significant aquatic plant communities, and with additional nutrients and harvesting of biomass. The removal of pharmaceuticals had half-lives that ranged from 0.23 to 9.4 days and 1.4 to 18 days during the summer and fall, respectively, and were predicted to occur primarily through photolysis and sorption. No overt toxicity from pharmaceuticals was observed for the common wetland macrophytes Myriophyllum sibiricum and Typha spp., but there was partitioning and bioaccumulation into macrophyte biomass. Treatment wetlands appeared to reduce pharmaceuticals and nutrients adequately, and may be a cost-effective means of treating rural wastewater.

2013-03-13T00:00:00Z Mahood, Thomas http://hdl.handle.net/1993/16594 2013-03-20T17:09:30Z 2013-02-13T00:00:00Z

Title: Differential innate immunity responses to West Nile virus and bacterial infections in mosquitoes Authors: Mahood, Thomas Abstract: Identifying the molecular interactions of pathogens in different mosquito species is critical for understanding how mosquitoes transmit diseases. In this study, the role of the Jak-STAT immune signalling pathway in two different mosquito species, (Aedes aegypti L.) and (Culex quinquefasciatus L.) was assessed. Using in silico analysis tools, cell culture, and molecular techniques, changes in gene expression were assessed during lipopolysaccharide (LPS) challenge and West Nile virus (WNV) infection in the two species. It was found that activation of the Jak-STAT pathway occurred more quickly in Ae. aegypti cells compared to Cx. quinquefasciatus cells during LPS exposure. During WNV infections, no significant differences were observed, although preliminary evidence suggests that differential activation of the Jak-STAT pathway may exist between the two species. This research extends our understanding of the mosquito immune system while demonstrating the critical importance of vector-virus interactions across different mosquito species.

2013-02-13T00:00:00Z