Rickey Yada

This study focussed on how collective mindfulness contributes to resilience in non-profit organizations coping with crises, such as the COVID-19 pandemic. Taking a Vancouver B.C. non-profit organization’s emergency food security response as a case study, it examines the role that mindfulness plays in non-profit organizations’ adaptations to the COVID-19 pandemic through the lens of complexity science. Specifically, it identifies emergent mindfulness processes and their effects on organizational resilience within non-profit organizations. This qualitative research employs a responsive, phronetic-iterative approach to interviewing and analysis that is grounded in a post-structuralist paradigm; attempts to advance a complexity-based theory of collective mindfulness; and furthers complexity science as a comprehensive interpretive framework. Findings demonstrate that collective mindfulness may be enacted through interdependent processes of dynamic reflexivity, responsive self-organization, and flexible co-evolution, through which resilience may emerge.

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Plants rely on their innate immunity as a first line of host defense against external pathogens. In potatoes, Solanum tuberosum, upon the infestation of the late blight disease causing pathogen, Phytophthora infestans, there is an increased expression of aspartic proteases. Most plant aspartic proteases are characterized by a hydrophobic signal peptide, a prosegment, and an N-terminal and C-terminal domain separated by a plant specific insert. Like saposins and various other members in this family, PSI of Solanum tuberosum was discovered to have antimicrobial and antifungal activities. PSI is active under acidic pH conditions by self-assembling into a dimer and it interacts with phospholipid membranes from pathogens to cause leakage activities. The objectives of this thesis were to elucidate the pH dependent protein monomer-dimer equilibrium and the backbone chemical shift assignments of PSI by solution NMR ,the dynamic properties of PSI by the NMR relaxation, PSI-membrane interaction by solid-state NMR, and the topology of PSI-membrane complex. A combination of solution state and solid-state NMR were used to study the characteristics of PSI in solution and PSI-membrane interactions at different pH conditions. Protein backbone assignments and dynamics characterization were performed on the PSI in solution. Protein-membrane interaction was examined through NMR titration, NMR based H/D exchange, and protein-lipid interactions by solid-state NMR. PSI monomer-dimer equilibrium occurred between pH 2.0 and 7.0. From dynamics studies, the average ¹⁵N longitudinal relaxation (T₁) times were 0.99 ± 0.18 s and 0.53 ± 0.03 s for pH 2.0 and 7.0, respectively, this demonstrated that PSI was a dimer at pH 2.0 and a monomer at pH 7.0. Comparison of the transverse relaxation (T₂) times of PSI at different pH values yielded the same conclusion. ¹H-¹⁵N heteronuclear NOE determined that PSI had rigid helical segments connected with flexible long loops. Solid-state NMR data suggested that protein-membrane interaction occurred on the phosphate head group and protein is embedded in the lipid environment after PSI-membrane interaction. These results contributed to protein dynamics and mechanisms of PSI and its interactions with phospholipid membrane, and therefore, a better mechanistic understanding of the innate natural plant host defense response against pathogen invasions.

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