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<p><strong>Introduction:</strong> Children with acquired brain injury (ABI) receive physiotherapy interventions to promote motor skill relearning. Theoretically-driven motor learning strategies (MLS) may support therapists in this goal, but their use with this complex population is unexplored. Virtual reality (VR) games are popular interventions that may influence therapist use of MLS. A valid, reliable method to examine MLS during usual and VR-based interventions is required.</p> <p><strong>Purpose: </strong>To: 1) identify the active ingredients of VR interventions; 2) develop and examine the psychometric properties of an instrument to measure MLS use; and 3) explore physiotherapists’ perspectives on promoting motor learning within usual and VR-based interventions for children with ABI.</p> <p><strong>Methods:</strong> A scoping review methodology was used to identify the active ingredients of VR interventions. Nineteen experts and clinicians participated in a content validation process to develop an instrument to measure MLS. Inter-rater reliability of the instrument was evaluated within 22 videotaped usual and VR-based physiotherapy sessions with children with ABI. Six therapists participated in qualitative interviews about these interventions.</p> <p><strong>Results:</strong> The scoping review identified<em> </em>11 active ingredients of VR; 6 related to motor learning theory. The Motor Learning Strategy Rating Instrument (MLSRI) was developed. Inter-rater reliability was high (0.81) for usual interventions but low (0.28) for VR-based interventions. Therapists described the importance of considering intervention goals and child characteristics when promoting motor learning; VR was viewed as a complex, motivating intervention that influenced their use of verbal strategies.</p> <p><strong>Conclusions:</strong> A motor learning theoretical framework may be relevant to clinicians and researchers using VR in pediatric rehabilitation. Qualitative findings enhance understanding of how therapists promote motor learning in usual and VR-based physiotherapy interventions for children withABI. The use of MLS can be measured reliably within usual interventions, but further instrument refinements are required to rate MLS use within VR-based physiotherapy for children with ABI.</p> / Doctor of Philosophy (PhD)

<p>Systemic Acquired Resistance (SAR) is a plant defense response induced by an initial infection in one part of the plant that leads to broad-spectrum resistance to normally virulent pathogens in distant naïve leaves. As part of the Cameron research team, I contributed to demonstrating that the lipid transfer protein, DIR1 is required for SAR long distance signaling in <em>Arabidopsis</em> and travels from induced to distant tissues during SAR. A highly similar<em> Arabidopsis</em> protein DIR1-like was identified and is thought to be responsible for the occasional SAR-competent phenotype observed in the <em>dir1-1</em> mutant. This work provides evidence for the idea that DIR1 and DIR1-like are paralogs created by a recent duplication event and that similar to DIR1, DIR1-like may travel to distant tissues during SAR. To better understand DIR1 and DIR1-like contribution during SAR, <em>dir1-1dir1-like</em> double mutant transgenic plants were created as well as transgenic plants expressing epitope- (HA and FLAG) and fluorescent- (iLOV and phiLOV) tagged DIR1 and DIR1-like to facilitate visualization of movement during SAR. Several putative DIR1 orthologs were identified in crop plants and cucumber CucDIR1 was shown to be functionally equivalent to AtDIR1 in <em>dir1-1</em> complementation studies providing further evidence that DIR1 plays an important role in SAR across plant species. By analyzing conservation between DIR1, DIR1-like and the putative DIR1 orthologs, several protein residues were identified that may be important for DIR1 function during SAR. DIR1 proteins were modified at these sites and the importance of these residues was supported by the reduced binding of the TNS hydrophobic probe in these DIR1 variants. Taken together, this thesis suggests that DIR1 and DIR1-like both participate in SAR in <em>Arabidopsis</em>, that DIR1 crop orthologs are also important for the SAR response and that DIR1 possesses several sites that are critical for its function in long distance SAR signaling.</p> / Doctor of Philosophy (PhD)

Greenhouse environments often promote bacterial and fungal infections in important crop plants. Exogenous application of chemical inducers could help reduce the severity of infection, or even prevent infection. Small molecules such as glycerol, azelaic acid and pipecolic acid have been implicated as being important signaling molecules during Systemic Acquired Resistance (SAR). To examine if these small molecules could be used to induce resistance in crop plants, exogenous treatment assays were developed in cucumber. Glycerol spray and azelaic acid infiltration induced modest resistance at locally treated leaves. Pipecolic acid soil treatment induced modest resistance in aerial tissue of cucumber plants, and strong resistance when plants were treated weekly. This knowledge may be useful in promoting the commercialization of SAR-associated compounds to protect important crop plants against disease. Plants possess multiple defense pathways that include an SA signaling component to initiate resistance to microbial pathogens. However, during Age-Related Resistance (ARR) in Arabidopsis, a number of studies support that SA acts as an anti-microbial and anti-biofilm agent against Pseudomonas syringae pv. tomato (Pst) in the plant intercellular space. Little is known about the role of Pst biofilm formation during infection of young plants or if other defense responses act to suppress bacterial biofilm formation. Therefore Pst biofilm formation and the effect of PAMP Triggered Immunity (PTI) on bacterial biofilm formation was examined. PTI was induced with flg22 in wild-type Col-0, fls2, bak1-3 (PTI mutants) and sid2-2 (SA biosynthesis mutant). In vivo bacterial biofilm-like aggregate formation was monitored using Pst DC3000 PDSK-GFPuv and epifluorescence microscopy. Pst aggregate occurrence and size were positively correlated with bacterial success in susceptible plants (wild-type Col-0, fls2, bak1-3, sid2-2), while fewer and smaller bacterial aggregates were observed in Col-0 undergoing PTI. To determine if the extracellular polysaccharide, alginate was a major contributor to biofilm formation, in vivo bacterial aggregate formation was monitored using alginate deficient Pst-GFP. Alginate deficient Pst-GFP and wild-type Pst grew to similar levels in wild-type plants suggesting that the ability to produce alginate was not necessary for Pst pathogenicity and success in planta. Fewer alginate-deficient Pst aggregates were observed compared to wild-type Pst in inoculated plants, suggesting that the ability to produce alginate was modestly important for aggregate formation. These data provide novel insights into how biofilms form in planta, the association between pathogen virulence and biofilm formation, and how plant defense responses such as PTI not only reduce bacterial growth, but also target biofilms. / Thesis / Master of Science (MSc)