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Three cycles of recurrent restricted phenotypic selection (RRPS) were carried out on two cultivars each of timothy (Phleum pratense L.) and orchardgrass (Dactylis glomerata L.). The selections were conducted at the E. A. Lods Agronomy Research Center of Macdonald Campus of McGill University from 1984 to 1988. Individual plant selections were based on dry matter yields of 25 plants. Within each of 16 grids, the five highest yielding genotypes were selected (i.e. 80 genotypes overall) and allowed to interpollinate. Equal weights of seeds from each of the 80 selected plants were mixed in each cycle. Evaluation trials were carried out in both sward and spaced stand from 1989 to 1993 to assess the effectiveness of selection in improving dry matter yield. Several other morphological and physiological characteristics of cycles were recorded to find possible associated changes. / Three cycles of RRPS were not effective in increasing forage dry matter yields. The lack of response may be due to a narrow genetic base in the source populations and/or the population size under selection may have been too small, resulting in inbreeding depression. Another explanation for the ineffective selection may be non-random pollination among selected plants. The selection for forage yield produced some minor changes in other characteristics. There was a tendency towards increased plant height and circumference in orchardgrass; however, for timothy, height and circumference were reduced by selection. Cycle 3 of Avon orchardgrass was one day later in maturity and there was also a tendency for later maturity for timothy.

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Thesis (Ph. D.)--University of Wisconsin--Madison, 1971. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

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Helmintheninfektionen induzieren in ihren Wirten Typ 2 (Th2) Immunantworten, welche parasitäre Larvenstadien hemmen und/oder zur Abstoßung von intestinalen Würmern führen. Th2-Antworten können auch gegenüber Umweltallergenen ausgebildet werden und allergische Reaktionen vermitteln. Mastzellen (MZ) spielen eine herausragende Rolle für die Wirtsantwort gegen Parasiten. Die Ergebnisse der vorliegenden Arbeit zeigen, dass eine Infektion von MZ-defizienten Mäusen mit Helminthen zu einer reduzierten Produktion von IL-25, IL-33 und TSLP, einer beeinträchtigten Etablierung von Th2 Immunantworten und einer erhöhten Wurmlast führt. Diese Parameter konnten allerdings nach einem erfolgreichen Transfer von Knochenmark aus Wildtypmäusen wiederhergestellt werden. Die vorliegende Arbeit beschreibt somit eine wichtige Funktion von Mastzellen für die Initialisierung von Th2 Immunantworten. Des Weiteren konnte gezeigt werden, dass ein Cystein-Protease-Inhibitor - AvCystatin sowohl Parameter von Atemwegsentzündung und -hyperreaktivität als auch Lieschgraspollen (Phl p 5b)-spezifische Immunantworten in einem klinisch relevanten Mausmodell für Atemwegsentzündung inhibiert. Gleichzeitig führte die Behandlung mit AvCystatin zu einem Anstieg von IL-10 und erhöhten Frequenzen von CD4+CD25+Foxp3+ T Zellen. Die in vivo Effekte von AvCystatin wurden unabhängig von der Protease-inhibitorischen Aktivität des Immunmodulators oder dessen Fähigkeit zur Oligomerisation vermittelt. AvCystatin unterdrückte zudem die Allergen-spezifische Produktion von IL-13 und induzierte in vitro unter Verwendung mononukleärer Zellen aus dem peripheren Blut (PBMCs) von Graspollen allergischen Patienten einen IFN-gamma vermittelten Th1 shift. Zusammenfassend tragen die Ergebnisse der Arbeit zu einem besseren Verständnis für die frühen Ereignisse von Th2 Immunantworten bei und zeigen, dass Helminthenmoleküle Bystandereffekte auf Immunantworten vermitteln können, die gegen andere Antigene gerichtet sind. / Helminth infections induce protective type 2 (Th2) immune responses in the host leading to arrested larval development and/or intestinal worm expulsion. Moreover, Th2 immune responses are initiated against harmless environmental allergens and mediate development of allergic disease. Among multiple mechanisms implicated in host responses to parasites and allergens, mast cells (MCs) play a pivotal role. The present study shows that MC-deficient mouse strains following infection with two gastrointestinal helminths had dramatically reduced early production of the tissue-derived cytokines IL-25, IL-33, and TSLP, which resulted in impaired induction of Th2 immune responses as well as increased parasite burden. These parameters were restored after transfer of WT bone marrow. These data reveal an important role for MCs in orchestrating type 2 immune responses. Parasites have developed various strategies to modulate the immune system via induction of a range of regulatory mechanisms. In this study AvCystatin, the filarial cysteine inhibitor, was found to inhibit airway inflammation and hyperreactivity induced by a clinically relevant allergen of timothy grass pollen (Phl p 5b). AvCystatin increased levels of the regulatory cytokine IL-10 and total numbers of CD4+CD25+Foxp3+ T cells. The immunomodulatory effect in vivo was found to be independent of AvCystatin’s protease inhibitor activity or oligomerization. Finally, AvCystatin suppressed allergen-specific production of IL-13 and created a shift towards Th1 immunity by increased levels IFN-gamma of human peripheral blood mononuclear cells (PBMCs) from grass pollen allergic patients. The findings contribute to a better understanding of the early events that dictate the priming of type 2 immune responses. Furthermore, helminth product-induced suppression may also have effects on bystander responses to unrelated antigens, thus, suggesting a promising preventive and therapeutic concept in the treatment of aberrant inflammations.