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:
- Wilson SL, Frazer C, Cumming BF, Nuin PAS, & Walker VK (2012) Cross-tolerance between osmotic and freeze-thaw stress in microbial assemblages from temperate lakes. FEMS Microb Ecol in press
- Wilson SL, Grogan P & Walker VK (2012) Prospecting for ice association: characterization of freeze-thaw selected enrichment cultures from latitudinally distant soils. Can J Micro 58: 402-12.
- Kumar N, Shah V& Walker VK (2012) Influence of a nanoparticle mixture on an arctic soil community. Environ Tox & Chem 31:131-35.
- Collins D, Luxton T, Kumar N, Shah S, Walker VK, Shah V (2012) Assessing the impact of copper & zinc oxide nanoparticles on soil: a field study. PLoS One 7:e42663.
- Ohno H, Moudrakovski I, Gordienko R, Ripmeester J & Walker VK (2012) Structures of hydrocarbon hydrates during formation with and without inhibitors. J. Physical Chem 116:1337-43.
- Wu Z, Kan FWK, She Y-M & Walker VK (2012) Biofilm, ice recrystallization inhibition & freeze-thaw protection in an epiphyte community. Appl Biochem & Micro 48:363-70.
- Middleton AJ, Marshall CB, Faucher F, Bar-Dolev M, Braslavsky I, Campbell RL, Walker VK & Davies PL (2012) Antifreeze protein from freeze-tolerant grass has a β-roll fold with an irregularly structured ice-binding site. J Mol Biol 416:713-24.
- Philbrook NA, Winn LM & Walker VK (2011) The effects of Ag and TiO2 nanoparticles on reproduction & development of Drosophila melanogaster and CD-1 mice. Toxicol & Appl Pharma 257:429-36.
- Philbrook NA, Walker VK, Afrooz ARMN, Saleh NB & Winn LM (2011) Investigating the effects of functionalized carbon nanotubes on reproduction & development in Drosophila melanogasterand CD-1 mice. Repro Toxicol 32: 442-48.
- Garnham C, Campbell R, Walker VK & Davies PL (2011) Novel dimeric beta-helical model of an ice nucleation protein with bridged active sites. BMC Struct Biol 11:36
- Chu H, Neufeld JD, Walker VK & Grogan P (2011) Soil bacterial, archaeal & fungal community structures among vegetation types in a low arctic tundra landscape. Soil Biol & Biochem 75:1756-65.
- Daraboina N, Ripmeester JA, Walker VK & Englezos P (2011) Natural gas hydrate formation & decomposition in the presence of kinetic inhibitors I: High pressure calorimetry. Energy & Fuels 25:4392-97.
- Daraboina N, Ripmeester JA, Walker VK & Englezos P (2011) Natural gas hydrate formation & decomposition in the presence of kinetic inhibitors II: Stirred microreactor experiments. Energy & Fuels 25:4384-91.
- Daraboina N, Ripmeester JA, Walker VK & Englozos P (2011) Natural gas hydrate formation & decomposition in the presence of kinetic inhibitors III: Structural & composition changes. Energy & Fuels 25:4398-404.
- Kumar N, Shah V & Walker VK (2011). Perturbation of an arctic soil microbial community by metal nanoparticles. J Hazardous Materials 190:816-822.
- Lauersen KJ, Brown A, Middleton A, Davies PL & Walker VK (2011) Expression & characterization of an antifreeze protein from the perennial rye grass, Lolium perenne. Cryobiology 62:194-201.
- Myran D, Middleton A, Choi J, Gordienko R, Ohno H, Ripmeester JA & Walker VK (2011) Genetically-engineered mutant and antifreeze proteins provide insight into hydrate inhibition. ICGH 7th http://www.pet.hw.ac.uk/icgh7/papers/icgh2011Final00687.pdf