Thesis (Ph. D.)--Oregon State University, 2000. / Typescript (photocopy). Includes bibliographical references. Also available on the World Wide Web.

Thesis (M.Sc.)--Acadia University, 1999. / Includes bibliographical references (leaves 44-59). Also available on the Internet via the World Wide Web.

Thesis (M.Sc.)--Acadia University, 1999. / Includes bibliographical references (leaves 44-59). Also available on the Internet via the World Wide Web.

La presente publicación pretende resumir el conocimiento científico químico-biológico sobre el Piper aduncum L., y sus especies sinónimas, P. angustifolium y P. elongatum. Se han logrado aislar e identificar más de 50 compuestos en dichas especies, los cuales pueden ser agrupados en cromenos, fenilpropanoides, derivados de ácido benzoico y flavonoides. Se presenta una discusión de las actividades biológicas encontradas para los extractos crudos y los compuestos aislados de ellos. / This review article covers the present knowledge on the chemistry and biological activities of Piper aduncurn and its synonyms P. angustifoliurn and P. elongaturn. More than 50 compounds have been isolated from these species, which can be grouped as chromenes, phenylpropanoids, benzoic acid derivatives and flavonoids. The biological activities of the crude extracts, and the compounds isolated from them, are discussed.

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

Toxic elements are present in polluted water from mines, industrial outlets, storm water etc. Wetland plants take up toxic elements and increase the pH of the medium. In this thesis was investigated how the shoots of submerged plants and roots of emergent plants affected the pH of the surrounding water in the presence of free toxic ions. The aim was to clarify the mechanisms by which these plants change the surrounding water pH in the presence of toxic ions. The influence of Elodea canadensis shoots on the pH of the surrounding water was studied in the presence of cadmium (Cd) at low initial pH (4-5). The involvement of photosynthetic activity in the pH changes was investigated in the presence and absence of Cd. The cytosolic, vacuolar and apoplasmic pH changes as well as cytosolic Cd changes in E. canadensis were monitored. The influence of Eriophorum angustifolium roots on the pH of the surrounding water was investigated in the presence of a combination of Cd, copper, lead, zinc and arsenic at low initial pH (3.5). Eriophorum angustifolium root exudates were analyzed for organic acids. Elodea canadensis shoots increased the pH of the surrounding water, an effect more pronounced with increasing Cd levels and/or increasing plant biomass and increased plant Cd uptake. The pH increase in the presence of free Cd ions was not due to photosynthesis or proton uptake across the plasmalemma or tonoplast. Cadmium was initially sequestered in the apoplasm of E. canadensis and caused its acidosis. Eriophorum angustifolium roots increased the surrounding water pH and this effect was enhanced in the presence of arsenic and metals. This pH increase was found to depend partly on the release of oxalic acid, formic acid and succinic acid by the plants. In conclusion, E. canadensis shoots and E. angustifolium roots were found to increase the low initial pH of the surrounding water. The pH modulation by these species was enhanced by low levels of free toxic ions in the surrounding water. / At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 2: Submitted. Paper 3: Submitted. Paper 4: Manuscript.

Perturbations to extravillous trophoblast (EVT) cell migration and invasion are associated with the development of placenta-mediated diseases. Dietary polyphenols have been shown to influence cell migration and invasion in models of tumorigenesis and non-cancerous, healthy cells; however, never shown in EVT cells. We hypothesize that polyphenols present in V. angustifolium leaves will promote trophoblast migration and invasion through ERK and AKT activation. Using the HTR-8/SVneo cell line as a model for EVT cells, the leaf extract increased trophoblast migration and invasion, in an ERK- and AKT-independent manner, and had no effect on cell proliferation or viability. One major polyphenol of the leaf extract was identified and may be an active compound. We have demonstrated for the first time that V. angustifolium leaf extract increases EVT migration and invasion in vitro, thus further investigations examining potential therapeutic applications of this extract in the context of placenta-mediated diseases are warranted.

L’abeille domestique (Apis mellifera L.) participe à la pollinisation commerciale des cultures de bleuets à feuilles étroites (Vaccinium angustifolium Ait.) et de canneberges (Vaccinium macrocarpon Ait.). Ce service de pollinisation représente 27% des revenus associés aux activités des apiculteurs au Québec (Canada). En participant à la pollinisation commerciale, les abeilles domestiques sont ainsi souvent exposées à des sources de pollen moins diversifiées qui pourraient alors contribuer à engendrer des carences nutritionnelles. Dans cette étude, nous avons élaboré quatre stratégies d’aménagement apicole (SA) avec pollinisation commerciale et mesuré leur impact sur le développement et la santé des colonies d’abeilles domestiques. Les groupes expérimentaux utilisés étaient : A) SA avec production de miel seulement (témoin); B) SA avec pollinisation commerciale du bleuet à feuilles étroites; C) SA avec pollinisation commerciale de la canneberge et D) SA avec double pollinisation, bleuet suivi de la canneberge. Nos objectifs étaient de 1) réaliser le suivi de colonies pendant une saison apicole complète dans différentes situations selon les SA, 2) identifier et comparer la diversité florale et son attrait pour les abeilles domestiques entre les ruchers expérimentaux en utilisant un système d’information géographique et le pollen récolté, 3) mesurer périodiquement le contenu en protéines et acides aminés du pollen récolté par les butineuses, par le biais des pelotes de pollen et du pain d'abeilles dans différentes situations selon les SA, et 4) comparer le développement et la santé des colonies d’abeilles domestiques entre les différentes SA tout au long d’une saison apicole complète. Nos résultats démontrent que l’abondance florale et son attrait pour les abeilles domestiques sont significativement plus faibles lors des services de pollinisation de la canneberge comparé aux autres SA. D’autre part, la concentration de protéines dans le pollen et le pain d’abeilles était significativement plus faible lors des services de pollinisation du bleuet, ce qui a engendré une plus faible surface de couvain. Dans ces deux cas, plusieurs acides aminés étaient en déficits mais ceux-ci n’étaient pas toujours en lien avec les SA. De façon générale, plusieurs déficits d’acides aminés essentiels (pollen et pain d’abeilles) ont été trouvés dans les trois ruchers et les quatre stratégies d’aménagement. La SA avec double pollinisation (bleuet et canneberge) a eu pour impact de réduire significativement le gain de poids des colonies, la récolte de pollen et la surface de couvain, et a également causé une mortalité hivernale plus importante. Nous avons de plus mesuré une quantité plus significative du virus de la cellule royale noire, du virus du couvain sacciforme et de Nosema ceranae lors de la SA avec double pollinisation. / Commercial pollination in lowbush blueberry (Vaccinium angustifolium Ait.) and cranberry (Vaccinium macrocarpon Ait.) crops benefit the presence of honey bee (Apis mellifera L.) for pollination and this pollination service represents 27% of the revenues from all seasonal beekeeping activities in Quebec (Canada). While providing such services, honey bees are often exposed to undiversified pollen sources that may contribute to nutritional deficiencies. In this study, we investigated four beekeeping management strategies (MS) and measured their impact on honey bee colony health and development. Experimental groups were: A) Control farmland honey producing MS (control MS); B) Blueberry pollination MS (blueberry MS); C) Cranberry pollination MS (cranberry MS) and D) Double pollination MS, blueberry followed by cranberry (double MS). Our objectives were to 1) monitor honey bee colonies during one year in different situations (according to the MS) 2) compare floral abundance and attractiveness of foraging areas to honey bees between apiaries using a Geographic Information System and harvested pollen, 3) analyze the protein and essential amino acid content of collected and stored pollen (bee bread) and measure the nutritional impact of pollination services on honey bee colonies and 4) compare honey bee colony health status and population development between MS during a complete beekeeping season. Our study reveals that honey bees providing blueberry and/or cranberry pollination services are exposed to a less diversified pollen diet than colonies located in a rich farmland environment. This was especially true for the cranberry crop environment. There was a significantly lower proportion of crude protein content in the pollen collected and stored by honey bees during provision of blueberry pollination services, which led to a smaller brood population. Regarding essential amino acids, many deficiencies were measured, however these were not always related to the management strategy. Globally, various essential amino acid deficiencies (harvested pollen or bee bread) were present at all three apiaries and four management strategies. The double MS significantly reduced colony weight gain, pollen harvest and brood population, and induced a significantly higher winter mortality rate. We also found significantly higher levels of Black queen cell virus, Sacbrood virus and Nosema ceranae in the double MS.

La pollinisation entomophile est un service écosystémique essentiel à la productivité de nombreuses cultures. Dans les agroécosystèmes, on observe généralement une diminution des pollinisateurs indigènes lorsqu'on s'éloigne des milieux naturels. Dans cette étude, nous avons évalué l'effet des milieux naturels et semi-naturels sur l'abondance et la richesse spécifique des pollinisateurs indigènes dans les bleuetières au Lac-St-Jean. Nos résultats démontrent que les pollinisateurs sont peu influencés par ces habitats, puisqu'ils sont majoritairement des nicheurs de sol, dépendant peu des zones boisées pour leur nidification. En revanche, on retrouve une abondance et une richesse spécifique supérieure en périphérie des bordures de forêt, étant donné qu'on y retrouve une disponibilité accrue en ressources nutritionnelles attrayantes pour ces insectes. De plus, ce projet a permis d'identifier des espèces possédant un meilleur potentiel de pollinisation, dû à leur grande capacité de transport de pollen et de leur spécificité vis-à-vis la fleur de Vaccinium angustifolium.

Berry ripening in lowbush blueberry (Vaccinium angustifolium Ait.) is influenced by developmental, physiological and climatic factors resulting in a heterogenous mix of maturities at harvest. This study characterizes the physico-chemical changes which occur during fruit ontogeny and links ripening patterns to micoclimate. Individual clones in five commercial fiels were followed in the 2006 and 2007 growing seasons. Phenolic acids, flavonols, and flavan-3-ols decreased and anthocyanins increased with maturity. Peak maturity consistently occurred at 1200 accumulated growing degree days (GDD). There was a sharp decline in fruit retention at the end of the growing season suggesting a date after which harvested yield declines but no consistent pattern was detected between years or fields.The consistency of GDD accumulation in relation to ripening pattern suggests GDDs can be used as a predictive ripening index. The physico-chemical nature of ripe berries indicates ripe berries could be harvested earlier than is currently the practice.