Virginia Walker - Professor
Research: Our research interests all concern stress genes and the molecular basis of resistance. This is a central question for scientific goals as diverse as predicting the outcome of cancer chemotherapy or planning the impact of global temperature fluctuations. For example, a study on the effects of methotrexate in fruit flies holds promise for understanding developmental abnormalities seen in human babies when mums are prescribed this drug. Similarly, nanoparticle administration may also impact development, and experiments on this potential stress are ongoing.
Environmental stress also challenges organisms, and we know that resistance to winter conditions has resulted in the evolution of stress genes encoding desiccation, cold and ice-binding proteins, including antifreeze proteins. We have cloned a number of these genes from sources as diverse as insects, plants and bacteria, and have applied novel selection techniques to identify microorganisms that encode molecules for cold adaptation. Among our recent discoveries is that antifreeze proteins inhibit gas hydrate formation. Hydrates plug up gas lines and are a multimillion-dollar problem to the gas and oil industry and if we could produce a “green” gas hydrate inhibitor, it would be a important contribution for environmental protection.
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Some Recent Publications:
- Sharifi, H., Ripmeester, J., Walker, V.K. & Englezos, P. (2014) Kinetic inhibition of natural gas hydrates in saline solutions and heptane. Fuel 117:109-117.
- Wilson S.L., Voordouw G. & Walker, VK (2014) Towards the selection of a produced water enrichment for biological gas hydrate inhibitors. Environmental Science & Pollution 10.1007/s11356-014-2912.
- Kumar N., Palmer, G.R., Shah V. & Walker V.K. (2014) The effect of silver nanoparticles on seasonal change in arctic tundra bacterial and fungal assemblages accepted with minor revisions PLoS ONE 9: e99953
- Vanderveer, T.L., Choi, J., Miao, D., & Walker, V.K. (2014) Expression and localization of an ice nucleating protein from a soil bacterium, Pseudomonas borealis Cryobiology 2014.06.001.
- Sharifi, H., Walker, V.K., Ripmeester, J. & Englezos, P. (2014) Insights into the behavior of biological clathrate hydrate inhibitors in aqueous saline solutions. Crystal Growth and Design 14: 2923–2930
- Sharifi, H., Walker, V.K., Ripmeester, J. & Englezos, P. (2014) Inhibition activity of antifreeze proteins with natural gas hydrates in saline and the light crude oil mimic, heptane Energy and Fuels: 28, 3712-3717.
- Han X, Geller, B., Moniz, K. Chippindale, A., Das, P. & Walker, VK (2014) Monitoring the developmental impact of copper and silver nanoparticle exposure in Drosophila and their microbiomes. Science of the Total Environment. 487:822-829.
- Shah V., Collins, D., Walker, V.K. & Shah, S. (2014) The impact of engineered cobalt, iron, nickel and silver nanoparticles on soil bacterial diversity under field conditions. Environ. Res. Lett. 9:024001.
- Middleton, A., Vanderbeld, B., Bristow, M., Tomalty, H. , Davies, P.L. and Walker, V.K. (2014) Ice recrystallization inhibition proteins from plants. In: Methods in Molecular Biology 1166: 255-77.
- Lauersen, K.J., Vanderveer, T., Berger, H., Kaluza, I., Mussgnug, J.H., Walker, V.K. and Kraus O. (2013) Expression and secretion of Lolium perenne ice binding protein with Chlamydomonas reinhardtii results in production of media with efficient ice recrystallization inhibition Plant Biotechnology J. 97:9763-9772.
- Kumar, N., Grogan, P., Chu, H., Christiansen, C.T. and Walker, V.K. (2013) The effect of freeze-thaw conditions on arctic soil bacterial communities. Biology 2: 356-377.
- Daraboina, N., Moudrakovski, I.L., Ripmeester, J.A., Walker, V.K. and Englezos, P. (2013) Assessing the performance of commercial and biological inhibitors using nuclear magnetic resonance microscopy and a stirred autoclave. Fuel 105: 630-635.
- Townson, I., Walker, V.K., Ripmeester, J.A. and Englezos, P. (2013) Bacterial inhibition of methane clathrate hydrates formed in a stirred autoclave. Energy and Fuels 26:7170-7175