Characterization of the chitinolytic system during the mycoparasitic interaction between Trichoderma aggressivum f. aggressivum and different host strains of Agaricus bisporus /

Green mould is a serious disease of commercially grown mushrooms, the causal agent being attributed to the filamentous soil fungus Triclzodenna aggressivum f. aggressivu11l and T. aggressivum f. ellropaellm. Found worldwide, and capable of devastating crops, this disease has caused millions of dollars in lost revenue within the mushroom industry. One mechanism used by TricllOdenlla spp. in the antagonism of other fungi, is the secretion of lytic enzymes such as chitinases, which actively degrade a host's cell wall. Therefore, the intent of this study was to examine the production of chitinase enzymes during the host-parasite interaction of Agaricus bisporus (commercial mushroom) and Triclzodemza aggressivum, focusing specifically on chitinase involvement in the differential resistance of white, off-white, and brown commercial mushroom strains. Chitinases isolated from cultures of A. bisporus and T. aggressivu11l grown together and separately, were identified following native PAGE, and analysis of fluorescence based on specific enzymatic cleavage of 4-methylumbelliferyl glucoside substrates. Results indicate that the interaction between T. aggressivulll and A. bisporus involves a complex enzyme battle. It was determined that T. aggressivum produces a number of chitinases that appear to correlate to those isolated in previous studies using biocontrol strains of T. Izarziallilm. A 122 kDa N-acetylglucosaminidase of T. aggressivu11l revealed the highest and most variable activity, and is therefore believed to be an important predictor of antifungal activity. Furthermore, results indicate that brown strain resistance of mushrooms may be related to high levels of a 96 kDa N-acetylglucosaminidase, which showed elevated activity in both solitary and dual cultures with T. aggressivum. Overall, each host-parasite combination produced unique enzyme profiles, with the majority of the differences seen between day 0 and day 6 for the extracellular chitinases. Therefore, it was concluded that the antagonistic behaviour of T. aggressivli1ll does not involve a typical response, always producing the same types and levels of enzymes, but that mycoparasitism, specifically in the form of chitinase production, may be induced and regulated based on the host presented.

Youth, Global Citizenship and Help: A Critical Rhetorical Analysis of Free The Children

Since 1995 Free The Children (FTC) has grown to be one of the largest and most recognized youth-focused and youth-led non-governmental organizations (NGOs) in Canada. FTC has distinguished itself by developing slick marketing campaigns, promising youth that they will become agents of change who can make a significant contribution towards eradicating poverty and promoting global social justice. The organization has utilized the Internet, creating an engaging and dynamic web page used to promote its development initiatives and celebrate the altruistic actions of its young participants. FTC uses a variety of strategies including text, video and images to persuade the viewer to engage with and elicit support for the organization. FTC attracts viewers by highlighting the successes of its overseas initiatives and the contributions made by young Northern volunteers in the global South. The organization also uses celebrity ambassadors, and cultural events such as We Day to raise its profile. Using a critical rhetorical analysis, this thesis interrogates FTC’s online promotional materials, exploring how the organization uses rhetorical strategies to persuade young people to take an interest in social justice activities. More specifically, an examination of FTC web-based promotional materials identifies and problematizes the organization’s rhetorical emphasis on youth empowerment, global citizenship and direct forms of helping the global South. This thesis argues that FTC does not direct adequate attention to fostering critical awareness among it participants. Further, the organization fails to provide its online participants with the appropriate tools or opportunities to critically engage with the structural issues related to global inequities. This thesis also examines how the organization uses rhetoric that promotes simplistic, feel-good projects that avoid exposing young people to an analysis of global social injustices.