Leishmaniasis is a disease affecting more than 12 million people worldwide. It is caused by the protozoan parasite Leishmania, which is transmitted to humans and dog hosts through bites of infected sand flies belonging to genus Phlebotomine. Several studies have shown Polymerase Chain Reaction (PCR) to be effective for the diagnosis of VL in clinical samples compared to the classical methods. The aims of this study were first to compare four different sample preparation methods for the PCR diagnosis of visceral leishmaniasis (VL) using peripheral blood samples and furthermore to find a method that is sensitive, rapid, cost benefit, simple and easy to perform. Two preparation methods were compared for the isolation of leukocytes (with Ficoll and Tris –EDTA buffer) and two DNA isolation methods (with Proteinase K and QIAgen kit). From the methods that were compared, lysis of erythrocytes with TE and the QIAgen kit seems to be the most suitable to use.

Although considerable research has been invested in disentangling the factors limiting species’ ranges at local and continental spatial scales, less attention has been granted to the relationship between species’ spatial distributions and landscape attributes at intermediate spatial scales. This research investigates the spatial relationship between avian species’ distributions (Ontario Breeding Bird Atlas [2001-2005] data) and landcover heterogeneity (Ontario Land Cover [1991-1998] data) in terms of their respective boundary locations (i.e., high rates of change in landcover composition and avian species turnover) in a vulnerable transitional zone in southern Ontario. Significant spatial overlap was found between landcover and avian boundaries. Given that land management decisions are most often made at the regional or landscape scales, this positive spatial relationship has important implications for conservation efforts. Future research should focus on assessing the spatial relationship between landcover heterogeneity and avian species’ distributions for different functional and taxonomic groups.

The purpose of this research project is to identify the species-level diversity and distribution of trees within the urban setting of Peel Region (Ontario, Canada) and to determine how these characteristics change as a function of land use type. To address this, alpha diversity (species richness within a community), evenness, and beta diversity (species richness between communities) were calculated for eight distinct land use types within the study area. As well, the influence that a variety of socioeconomic and urban form variables have in determining urban forest composition was examined using regression techniques. Results indicate that significant relationships exist between land use type, species richness and overall tree abundance. Variables reflecting wealth and urban form are also shown to significantly influence tree abundance. The results of this study address issues pertaining to the adaptation, conservation, and management of the region’s urban tree species.

Rationale/ Hypothesis: Reactive oxygen species, including lipid hydroperoxides, play a critical role as second messengers in many physiological processes in the body. Heightened reactive oxygen species production at the time of birth imposes an oxidative stress upon the lung, which may trigger postnatal alveologenesis and physiological lung cell apoptosis in the neonatal rat. Methods: Neonatal rats were subcutaneously injected daily with vehicle (corn oil) or diphenyl-phenyl diamine for the first 6 days of life to study alveologenesis and physiological lung cell apoptosis. Add-back experiments were conducted with a prototypic lipid hydroperoxide, t-butyl hydroperoxide. Main Results: Treatment with diphenyl-phenyl diamine resulted in parenchymal thickening, reduced numbers of secondary crests and enlarged air spaces, all consistent with the inhibition of alveologenesis and reduced physiological lung cell apoptosis. Conclusion: Following an oxidative stress at birth, lipid hydroperoxide formation triggers postnatal alveologenesis and physiological lung cell apoptosis in the neonatal rat.

The development of plants challenged by environmental stress alters plant architecture through several pathways, including those involving plant hormone responses and reactive oxygen species (ROS) production. Auxin, a phytohormone associated with every aspect of development, and abscisic acid (ABA), a phytohormone involved in abiotic stress responses, both interact with ROS. These ROS are used as secondary messengers to activate transcription of abiotic stress genes, and also in developmental responses such as cell elongation. To understand the mechanisms involved in the abiotic stress response and how the response intersects with auxin, ABA, and ROS, I examined COPPER INDUCED IN LEAVES 1 (<i>CIL1</i>) from <i>Brassica carinata</i> and its Arabidopsis orthologue, AUXIN INDUCED IN ROOTS 12 (AIR12). Expression of both genes increases in response to auxin and recent work has placed both <i>CIL1</i> and AIR12 within a family of plant-specific cytochrome b561 proteins thought to be involved with transmission of ROS signals. This suggests a link between auxin and ROS production resulting from abiotic stress. Antisense <i>CIL1 B. carinata</i> plants produced fewer lateral roots and were resistant to salinity stress during vegetative growth. Mutant air12 plants showed a 50% reduction in lateral root number, lateral root length, and H2O2 root distribution. Growth in the presence of H2O2 was able to restore lateral root length to control levels. In silica analysis of the <i>CIL1</i> and AIR12 amino acid sequences detected an attachment site for glucosylphosphatidylinositol, predicting that the protein is targeted to the extracellular leaflet of the plasma membrane where it could be cleaved and released into the apoplast. Subcellular localization using p35S::GFP-CIL1 and p35S::GFP-AIR12 translational fusions confirmed that CIL1 and AIR12 localize to the plasma membrane and are released into the apoplast. Organ localization of AIR12 using the pAIR12::GFP-AIR12 construct in stably transformed Arabidopsis showed fusion protein accumulation in the apex of the primary root and in the vascular tissue. Fusion protein also localized to cells flanking emerging lateral roots. Investigation of pAIR12::GUS Arabidopsis showed GUS accumulation in the apex of elongating lateral roots. I demonstrate that AIR12 is an extracellular protein and that air12 seedlings are susceptible to salt stress, but not osmostic stress and display increased and decreased sensitivity to ABA during germination and primary root elongation, respectively, suggesting that AIR12 acts downstream of abiotic stress recognition.

The study of species diversity patterns and their causes remains a central theme of ecology. Work conducted over the last few decades has shown that both historical and ecological factors are important in determining species diversity patterns. Additionally, different causal mechanisms are important at different spatial and temporal scales. At the regional scale, species diversity patterns can best be studied in terms of three diversity components (alpha, beta and gamma). This study used the amphibians and reptiles of Costa Rica to examine these species diversity components at the regional scale. To accomplish this, existing species lists were compiled from the literature. Additionally, three herpetofaunal surveys were conducted at under surveyed sites to fill knowledge gaps. A survey of Parque Nacional Carara, a transitional zone site on Costa Rica’s central Pacific coast, gave evidence of a rich herpetofauna, containing species from both the dry tropical forest to the north and the wet lowland forest to the south. Survey results show that Carara’s herpetofaunal assemblage is more similar to that of the wet forest than the dry forest, and suggest many species from both assemblages reach their range limit at or near the park. Surveys of four sites in the eastern Área de Conservación Guanacaste showed rich herpetofaunal diversity and validated the newly purchased Rincón Rainforest as an important conservation area. A survey of Reserva Natural Absoluta Cabo Blanco provided a preliminary list of amphibian and reptile species of the lower Nicoya Peninsula and highlighted the importance of Laguna Balsitas to the local amphibian fauna. A comparison of amphibian and reptile alpha diversity among 17 sites throughout Costa Rica showed highest alpha amphibian diversity in the lowland rainforests of the Pacific versant and highest reptile alpha diversity in lowland rainforests of the Atlantic versant. An analysis of beta diversity produced dendrograms showing sites within lowland ecoregions being most similar. A Canonical Correspondence Analysis (CCA) of environmental variables showed two climate gradients, an elevation/temperature gradient and a sun/rain gradient, to be important in determining species diversity patterns for both amphibians and reptiles in Costa Rica.

Decision support systems (DSS) that integrate long-term duck population and land use data are currently being used to develop conservation programs on the Canadian prairies. However, understanding inter-relationships between ducks and other grassland bird species would greatly enhance program planning and delivery among various bird conservation initiatives. Therefore, to achieve these goals, grassland bird species richness and relative abundance were compared between areas of low, moderate and high predicted waterfowl breeding densities (strata) in the southern Missouri Coteau, Saskatchewan. Roadside point counts were conducted during spring 2001 and 2002, and habitats were delineated within 400 m radius of each point. More birds of more species were encountered in the high density waterfowl stratum when compared with low but species that tended to co-occur with ducks were primarily wetland-associated. Overall, duck and other grassland bird species richness and abundance were moderately correlated (0.69 > r > 0.37, all Ps < 0.05); strong positive correlations between priority species of conservation concern and northern pintails were not found. No difference in mean number of priority grassland species occurred among strata, but differences were found for both number of species and total birds detected among routes within strata. High duck density stratum was more heterogeneous, consisting of greater areas of forage, shrub, wetlands, and open water bodies whereas low stratum contained larger, more uniformly-shaped habitat patches and greater proportion of cropland. Ordination analyses revealed that most priority species occurred in grassland-dominated sites with lower shrub area and wetland density whereas most wetland-associated species, including ducks and 2 priority species (Wilsons phalarope and marbled godwit) inhabited cultivated areas with higher wetland density. Ducks and priority species generally did not co-occur at the stop-level in highly heterogeneous landscapes but suitable habitats for both groups may exist in near proximity. In homogeneous landscapes, ducks and other wetland-associated common species were less abundant because of limited number of suitable wetlands. To achieve these dual goals, conservation efforts should be focused in areas containing wetlands adjacent to contiguous tracts of native pasture.

Invasive species are one of many important environmental issues facing Canadians today. A great deal of research has explored both the scientific and social aspects of invasive species. However, the cumulative research has not yet thoroughly explored people’s thoughts and feelings about, or perceptions of, invasive species and the influence these may have on management of, or policy decisions regarding, invasive species. This thesis research project was designed to assess the attitudes and perceptions that high school students have towards invasive species and to determine to what extent learning about invasive species alters their connection with nature. The study group was comprised of students from four Grade 11 Environmental Science classes from three high schools within the city of Guelph, Ontario. The students received regular classroom instruction from their teachers covering the course content, including invasive species. Students also made weekly visits to a local nature centre, providing them with hands-on learning experiences related to the course content. Students responded to an 80-question survey that assessed their knowledge of local invasive species and attitudes towards them as well as students’ connection to nature. Their connection to nature was assessed using a modified version of the Connectedness to Nature Scale (Mayer & Frantz, 2004). The surveys were administered by the classroom teachers in October, 2010, prior to the presentation of instructional material covering invasive species and then again in December, 2010 when the presentation of instructional material concerning invasive species was complete. The results showed that the students’ knowledge of invasive species upon entering the course was quite low and each of the classes witnessed a significant increase in knowledge. The survey results did not reveal any change to the students’ connection to nature; however, they did reveal three underlying themes in students’ attitudes towards invasive species: a concern about invasive species as a threat or problem; feelings of acceptance towards invasive species; and feelings of anxiety about invasive species. These attitudes remained relatively unchanged after the course.

The development of plants challenged by environmental stress alters plant architecture through several pathways, including those involving plant hormone responses and reactive oxygen species (ROS) production. Auxin, a phytohormone associated with every aspect of development, and abscisic acid (ABA), a phytohormone involved in abiotic stress responses, both interact with ROS. These ROS are used as secondary messengers to activate transcription of abiotic stress genes, and also in developmental responses such as cell elongation. To understand the mechanisms involved in the abiotic stress response and how the response intersects with auxin, ABA, and ROS, I examined COPPER INDUCED IN LEAVES 1 (<i>CIL1</i>) from <i>Brassica carinata</i> and its Arabidopsis orthologue, AUXIN INDUCED IN ROOTS 12 (AIR12). Expression of both genes increases in response to auxin and recent work has placed both <i>CIL1</i> and AIR12 within a family of plant-specific cytochrome b561 proteins thought to be involved with transmission of ROS signals. This suggests a link between auxin and ROS production resulting from abiotic stress. Antisense <i>CIL1 B. carinata</i> plants produced fewer lateral roots and were resistant to salinity stress during vegetative growth. Mutant air12 plants showed a 50% reduction in lateral root number, lateral root length, and H2O2 root distribution. Growth in the presence of H2O2 was able to restore lateral root length to control levels. In silica analysis of the <i>CIL1</i> and AIR12 amino acid sequences detected an attachment site for glucosylphosphatidylinositol, predicting that the protein is targeted to the extracellular leaflet of the plasma membrane where it could be cleaved and released into the apoplast. Subcellular localization using p35S::GFP-CIL1 and p35S::GFP-AIR12 translational fusions confirmed that CIL1 and AIR12 localize to the plasma membrane and are released into the apoplast. Organ localization of AIR12 using the pAIR12::GFP-AIR12 construct in stably transformed Arabidopsis showed fusion protein accumulation in the apex of the primary root and in the vascular tissue. Fusion protein also localized to cells flanking emerging lateral roots. Investigation of pAIR12::GUS Arabidopsis showed GUS accumulation in the apex of elongating lateral roots. I demonstrate that AIR12 is an extracellular protein and that air12 seedlings are susceptible to salt stress, but not osmostic stress and display increased and decreased sensitivity to ABA during germination and primary root elongation, respectively, suggesting that AIR12 acts downstream of abiotic stress recognition.

Ischemic stroke is characterized by a disruption of blood supply to a part of the brain tissue, which leads to a focal ischemic infarct. The expression and activity of MMP-9 is increased in ischemic stroke and is considered to be one of the main factors responsible for damages to the cerebral vasculature, resulting in compromised blood-brain barrier (BBB) integrity. However, the regulatory mechanisms of MMP-9 expression and activity are not well established in ischemic stroke. Since hypoxia/ischemia and reperfusion generates reactive oxygen species (ROS), I hypothesize that ROS is one of factors involved in up-regulation of MMP-9 expression in brain cells and ROS-mediated effect may occur via MAPK signaling pathway. My study has provided the evidence that ROS is responsible for an increase in MMP-9 expression in astrocytes mediated via MAPK-AP1 signaling pathway. Preliminary studies with an in vitro model of the BBB suggest that inhibition of MMP-9 is a critical component of reducing ROS-induced BBB permeability.