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:
• Das P, McDonald, JAK, Petrof, EO, Allen-Vercoe E, Walker VK (2014) Nanosilver-mediated change in human intestinal microbiota. J. Nanomedicine & Nanotechnology 5:235.
• Shi Y., Xiang C, Shen C., Chu, Neufeld J, Walker VK, Grogan P (2014) Soil bacterial and eukaryotic microbial distributions among vegetation types in a low Arctic tundra landscape. Applied Environ Microbiol. In press
• Tomalty HE & Walker, VK (2014) Perturbation of bacterial ice nucleation activity by a grass antifreeze protein. Biochem Biophys Research Comm. 452: 636-641
• Guo W, Wu Z, Song J, Jiang F, Wang Z, Dong S, Walker VK & Zhou S. (2014) Juvenile hormone-receptor complex acts on Mcm4 and McM7. PLoS Genetics In press
• Sharifi H, Ripmeester J, Walker VK & Englezos P (2014) Kinetic inhibition of natural gas hydrates in saline solutions and heptane. Fuel 117:109-117
• Wilson SL, Voordouw G & Walker, VK (2014) Towards the selection of a produced water enrichment for biological gas hydrate inhibitors. Environ. Sci & Pollution 10.1007/s11356-014-2912.
• Kumar N, Palmer GR, Shah V & Walker VK (2014) The effect of silver nanoparticles on seasonal change in arctic tundra bacterial and fungal assemblages. PLoS ONE 9: e99953
• Vanderveer TL, Choi J, Miao D, & Walker VK (2014) Expression and localization of an ice nucleating protein from a soil bacterium, Pseudomonas borealis Cryobiology 69: 110-118.
• Sharifi H, Walker VK, Ripmeester J & Englezos P (2014) Insights into the behavior of biological clathrate hydrate inhibitors in saline solutions. Cry. Growth & Design 14: 2923–30.
• Sharifi H, Walker VK, 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 VK & Shah S. (2014) The impact of engineered cobalt, iron, nickel and silver nanoparticles on soil bacterial diversity under field conditions. Environ. Res. Letters 9:024001.
• Middleton A, Vanderbeld B, Bredow M, Tomalty H, Davies PL & Walker VK (2014) Isolation and characterization of ice-binding proteins in plants. Methods in Mol. Biol. 1166: 255-77