Exploring several nonconventional interactions of ice-binding proteins

Traditionally, ice-binding proteins (IBPs), also known as antifreeze proteins (AFPs), have been defined by two universal activities: ice recrystallization inhibition and thermal hysteresis. However, there remains the possibility IBPs have other complementary functions given the diversity found within this protein group. This thesis explores some of these in both natural and applied settings, in the hopes of furthering our understanding of this remarkable group of proteins. Plant IBPs could function as part of a defensive strategy against ice nucleators produced by certain pathogens. To assess this hypothesis, recombinant IBPs from perennial ryegrass and purple false brome were combined with the ice nucleation protein (INP) from the plant pathogen, Pseudomonas syringae. Strikingly, the plant proteins depressed the freezing point of the bacterial INP, while a fish AFP could not, nor did the INPs have any effect on IBP activity. Thus, the interaction between these two different proteins suggests a role in plant defensive strategies against pathogenic bacteria as another IBP function. In addition, the potential use of hyperactive insect IBPs in organ preservation was investigated. Current kidney preservation techniques involve storing the organ at 4 °C for a maximum of 24 h prior to transplantation. Extending this “safe” time would have profound effects on renal transplants, however, ischemic injury is prevalent when storage periods are prolonged. Experiments described here allowed subzero preservation for 72 h with the addition of a beetle IBP to CryoStasis® solution. Kidneys stored using the traditional technique for 24 h and the method developed here for 72 h showed similar levels of biomarker enzymes, underscoring the potential utility of insect IBPs for future transplant purposes. Finally, IBP function in the freeze-tolerant gall fly, Eurosta solidaginis, was examined. Larvae representing the mid-autumn stage displayed ice-binding activity, suggesting an IBP is being expressed, possibly as a protective measure against freezing damage when fall temperatures can unpredictably drop. IBP activity was also observed in the larvae’s host plant, Solidago spp. Mass spectrometry analysis of ice-affinity purified plant extracts provided three candidate pathogenesis-related proteins that could be responsible for the detected activity, further demonstrating additional functions of IBPs.

Stitching Settler Identities: Canadian Quilts and Their Makers, 1800-1880

Stitching Settler Identities: Canadian Quilts and their Makers, 1800-1880 explores the making, use, and circulation of handmade settler quilts as representation of nineteenth-century women’s social, cultural and economic histories in Canada. An important part of Canadian settlement history is the making and use of handmade quilts in the settler homestead. Handmade coverlets that provided both physical and emotional warmth in the home were a measure of a settler-woman’s careful management of resources and a display of her innovation and creativity. Few settler women recorded their daily experiences; however, most women could sew and quilts offered a method of expression that allowed them to reflect and portray their identities. Thus far, the few studies of quilts have been limited to exhibition catalogues or research that considers a quilt’s aesthetics or its historic significance. While several scholars have called for a reclassification of textile production and needle arts to advance the way in which settler women were viewed as social beings – creating, producing, communicating, and circulating cultural values, most studies on quilts have overlooked a coverlet’s materiality. This study aims to expand the research on quilts as material culture within the context of art history by also considering a quilt’s materiality and when possible, its maker's biography.