Doctor of Philosophy in Integrated Studies in Land and Food Systems (PhD)
Healing Synergies: Indigenous Land-based Pedagogies and Indigenous Food Sovereignty in the City
Dissertations completed in 2010 or later are listed below. Please note that there is a 6-12 month delay to add the latest dissertations.
This work is an ethnography of queer farmers throughout British Columbia and acknowledges that by working within such a diverse population, there exists no singular representation of “queer individuals,” “farmers,” and / or “queer farmers.” The research design integrates a qualitative, post-structuralist ethnographic and auto-ethnographic methodology based upon individual narratives and a review of both local (British Columbia) and non-local (national and international) print and web sources (academic and non-academic) related to gender, and especially sexuality, in agricultural production and practice. This study recognizes the existence of ecologies of social difference. I define ecologies of social difference as the role of ecological indicators, settings, and contexts as mediators and moderators in the intersections of social difference (i.e., the role of ecology in shaping both positively and negatively greater inequalities, inequities, injustices). This study draws from several intellectual lineages, from queer theory to feminist political ecology, to illustrate how agriculture might be transformed within a queer ecological context. Rooted in my belief that understandings of agriculture and ecology are shaped and impacted by gender and sexuality even as understandings of gender and sexuality are shaped and impacted by practices within and perceptions of agriculture and ecology, this work seeks to challenge heteronormative assumptions of both gender and sexuality and agriculture and ecology. It presupposes that queer sexualities can provide lenses through which farmers are not only creating new agricultural practices, but also new queer identities. These new, heretofore unstudied, lenses may then lead to the identification of new perspectives, practices, innovations and understandings of agricultural and ecological sustainability.
Chemical compositions of plant essential oils can be affected by many environmental and biological factors. Understanding the role of individual constituents and their interactions to overall insecticidal bioactivity is prerequisite to the use of essential oils as an alternative to conventional insecticides. In the present study, the chemical compositions of Rosmarinus officinalis (rosemary), Thymus vulgaris (thyme) and Cymbopogon citratus (lemongrass) essential oils were analyzed by gas chromatography-mass spectrophotometry (GC-MS), and relationships between chemical composition and toxicity of the constituents, and synergistic interactions of the major constituents of the oils were evaluated against third instar larvae and an ovarian cell line of the cabbage looper, Trichoplusia ni, via different application methods. To explore underlying mechanisms of synergy, penetration through the insect cuticle and inhibitory activities on three detoxifying enzyme systems were investigated. The most abundant constituents of rosemary, thyme and lemongrass oils were 1,8-cineole, thymol and citral, respectively, and their overall contributions to in vivo and in vitro toxicity varied according to the application methods, as did their designation as major active principles. A weak correlation between insecticidal activity and cytotoxicity was observed, indicating limitation of insect cell cultures as a screening tool for novel insecticides. Several synergistic interactions were found among the major constituents of each oil, including 1,8-cineole+camphor, thymol+p-cymene and citral+limonene. Analysis by GC-MS showed a significant penetration-enhancing effect of topically applied camphor by 1,8-cineole in their synergistic binary mixture. 1,8-Cineole was more toxic than camphor when applied topically to larvae, but a bioassay via injection revealed greater toxicity of camphor than 1,8-cineole. A bioassay combining injection and topical application confirmed the increased penetration of both compounds when mixed, showing the same bioactivity with higher amounts applied individually. A similar pattern of enhanced penetration of insecticides through the cuticle of T. ni in other synergistic combinations was observed as well. Lowered surface tension and increased solubility along with the interaction between essential oil constituents and the lipid layer of the insect’s cuticle may explain their enhanced penetration. Although some mild enzyme inhibitory activities were observed in essential oil-treated larvae, no correlation was observed between detoxicative metabolism and synergistic toxicity.
Theses completed in 2010 or later are listed below. Please note that there is a 6-12 month delay to add the latest theses.
The negative impact of agricultural pesticides on the environment are well documented. This in vitro study evaluates the biological activity of seven British Columbia native plant extracts and plant extracts fermented with Saccharomyces cerevisiae, against three plant pathogens of economic importance: Phytophthora infestans, Fusarium sambucinum and Pectobacterium carotovorum. Crude plant extracts and yeast-fermented extracts using simple fermentable media and Saccharomyces cerevisiae were evaluated, while the pathogen growth development was challenged against in vitro treatments. Dry plant extracts were prepared by dissolving 5 mg of crude extract in 2.5 ml of 70% ethanol; then different concentrations were prepared in 96 wells microliter plates and tested against the selected organisms. The 4- way interaction model (yeast, extract, solvent, treatment dilution) was used for the analysis, and the significance of the interaction in the models was tested by a likelihood ratio test. Moreover, 262 combinations out of 480 of either crude extracts, or fermented extracts applied at different dilutions with different solvents (methanol or water) showed growth inhibition in comparison to controls. Arbutus menziesii treatments, including fractions of the crude extract, demonstrated the most diverse levels of growth suppression of all the pathogens. Fermentation has shown great potential for increasing the extract efficacy. In some cases, a combination of the fermentation period and the extract concentration influences the biological activity of specific treatments. Even though treatments that included water as a solvent mixed with the pathogen culture indicated pathogen suppression, when applied as a solvent, methanol showed preferable scales of inhibition. Moreover, results showed that several fermented treatments inhibited pathogen growth, whereas in many cases, the same treatments did not show the same inhibition when they were tested as crude extracts. This was observed with a 24-hour fermentation of water and methylene dichloride fractions of Arbutus menziesii, Maianthemum stellatum extract, and Rubus spectabilis extract applied against F. sambucinum and P. infestans. Further research is encouraged to identify potentially active compounds, but also to evaluate the fermentation treatments and factors influencing the combinations. Plant fermentation may offer a new opportunity in the development of more ecological and safer biopesticides.
Today, much of the agricultural production and food security (FS) in developing countries relies on women. They play critical roles in the availability, access and utilization of food at household and community levels. Women’s roles, however, are underestimated and constrained by restricted access to resources, services and labour market opportunities. Despite their fundamental position in global FS, the majority of undernourished people are women and girls. Failing to recognize the existence of gender exclusion and unequal gender dynamics perpetuates the current status of women and increases the risk of food insecurity. Thus, it is crucial to acknowledge that households and communities are gendered entities. This research aims to improve the understanding of gender participation in FS at the household and community levels in agricultural indigenous communities in the South Andean highlands. These communities are part of the indigenous campesinos (peasants) population that meaningfully contributes to produce food in Peru and other Latin American regions. The research focuses on women’s physical and decision-making tasks regarding production, accessibility and utilization of food for their families and communities. This case study centers on two Quechua agricultural communities in the Cusco Region, Peru, and used qualitative mixed methods for data collection and analysis. The results suggest that in these communities FS is mainly a household and not a community matter. At the community level, communities are more organized to perform civil, rather than agricultural work. They produce food mostly to generate income to cover administrative expenses. Women head labour and decision-making regarding household FS, but have not relevant role at the community level; they are more involved in lower levels of participation in community political and labour structure. The egalitarian farming is the prevalent system in the household: women and men provide labour and control decision-making. In the community, the prevalent farming system is patriarchal: both genders provide labour but men control decision-making. Addressing FS in these communities requires acknowledging inequalities and strengthening ancient gender relations and agricultural practices.
In grape and some other fruits used for wine making, abscisic acid (ABA) has been demonstrated to be involved in regulating fruit development. ABA metabolism has been characterized in the model plant Arabidopsis thaliana and shown to involve at least three catabolic pathways that inactivate free ABA. Abscisic acid UDP-Glycosyltransferase (ABA-UGT), a member of Glycosyltransferase (GTs) protein family 1, is a key enzyme in the abscisic acid metabolism which leads to the deactivation of ABA. ABA-UGT catalyzes the glucosylation process from abscisic acid to its conjugated metabolite abscisic acid glucose ester (ABA-GE) in planta. ABA-GE is a terminal product of the ABA metabolic pathway and does not appear to have any biological function. Thus, manipulation of ABA-UGT in wine-making fruits will offer a possibility to control the metabolism of ABA with the potential to optimize the ripening of fruit. In this study, genomic and biochemical approaches were used to attempt to identify ABA-UGT in Vitis vinifera, the European grapevine species most widely used in wine making. The identification of ABA-UGT can be a foundation for further research about how ABA is involved in the fruit development and other processes in grapevine.
Melanins are a diverse group of pigmented biopolymers present in living organisms at all phylogenetic levels. Properties such as light scattering and absorption through a wide range of wavelengths, and scavenging of free radicals are common to all melanins, and render them as molecules having the capacity to protect against UV damage. Fungal melanins are more chemically diverse than animal melanin, and have radioprotective properties. In this research, I isolated melanins from the basidiomycete Agaricus bisporus and the ascomycete Grosmannia clavigera, and assessed their photoprotective effect in human skin cells. Both fungal melanins differed in physicochemical characteristics and functional groups evidenced by infrared spectral analyses. Differences in the evaluated bioactivity were also observed. Agaricus bisporus melanin behaved similar to synthetic DOPA melanin, significantly enhancing cell viability measured by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay in human dermal fibroblasts irradiated with a high dose of ultraviolet B (UVB). Agaricus bisporus melanin also effectively reduced the amount of reactive oxygen species (ROS) induced by UVB in these cells. Measurements of light transmission at 315 nm of melanin solutions suggest that the observed photoprotective effect was likely to be due to a UV filter effect. No photoprotection was observed in cells exposed to UVB in the presence of Grosmannia clavigera melanin. Unlike synthetic DOPA melanin, both fungal melanins were potentially cytotoxic for human dermal fibroblasts. My results suggest that differences observed in the fungal melanin bioactivity are possibly linked to differences in their chemistry and optical properties.
In this thesis I present a community-based participatory research project analyzing principles for the management of non-timber forest products within Westbank First Nation (WFN). This work situated WFN perspectives within current research on Aboriginal understandings of human and ecological health. The mixed method approach of this project utilized qualitative community knowledge and quantitative, field-based research. The results from the qualitative components detail community understandings of the connection between plants, health, and the environment. These connections were summarized in community principles for managing native flora and creating culturally-grounded ecological education. The quantitative research component analyzed the current distribution characteristics of Shepherdia canadensis (L.) Nutt., Elaeagnaceae within the Central Okanagan. Distribution characteristics and various plant community associations were analyzed using a plot-based field methodology. This information was compared to community input regarding the historical distribution of Shepherdia canadensis (Okanagan - sxʷusəm) in the region. The current fragmented distribution of Shepherdia canadensis implies the potential for a broad historical access to this plant at low elevations. This broad distribution was in accordance to the accounts of some community members. This particular information provided an example of how traditional ecological knowledge (TEK) has the potential to improve questions within resource management practice. On a broader level, this data provided some context to discuss effectively co-managing for resources within changing ecosystems. As a whole, this thesis presents an example of how Aboriginal perspectives of health and ecology relate to their conceptions of managing resources and how these perspectives should be engaged to promote effective management practice.