Vanya Ewart

HALIFAX, NOVA SCOTIA | CANADA B3H 1X5 | +1 (902) 494-2480

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UNDERGRADUATE PROGRAMS

Faculty Members

Dr. K. V. Ewart, Ph.D.

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Dr. Vanya Ewart, Ph.D. (Memorial University, Newfoundland)

Adjunct Professor
Senior Research Officer, National Research Council, Institute for Marine Biosciences

(902) 426-0636

Email: Vanya.Ewart@nrc-cnrc.gc.ca

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Research Areas:

Our research aims to develop new products and processes in marine biotechnology. All projects include dynamic collaborations with other teams, as will be evident from the authorship of publications.

Low temperature biology in the marine environment

1. Glycerol accumulation in rainbow smelt: Smelt (Osmerus mordax) accumulate extreme concentrations of glycerol (200-500 mM) during winter. Glycerol is a natural colligative antifreeze agent that can lower the freezing point of fish blood, thereby promoting fish survival in cold oceans. Glycerol is also a well-known "chemical chaperone" that can enhance the folding and stability of proteins in much the same way as the heat-shock (chaperone) proteins. qPCR analysis of metabolic enzyme gene expression has provided insight into mechanisms of glycerol production in smelt and subtractive hybridization has shown a number of key genes to be up- or down-regulated in winter smelt with high glycerol compared with autumn controls, which provides new insight into cold adaptation. 2. Excellent cold adaptation in smelt: We are using the cGRASP 16K salmon cDNA array to identify differentially expressed genes in smelt during winter to uncover elements of its excellent adaptation to low and freezing temperatures. 3. Antifreeze protein dosage in winter flounder: In related work, we are examining the gene dosage and antifreeze protein levels in winter flounder (Pleuronectes americanus), in order to choose the best populations for aquaculture.

Recognition of "non-self" in the marine environment

1. Soluble C-type lectins in salmon: A C-type mannose-binding lectin from Atlantic salmon (Salmo salar) serum binds bacteria and has a role in innate immunity. Using genomic and cDNA clones and a polyclonal antibody against the lectin, we are studying its molecular-level characteristics, its binding functions and its role in immunity. In related work, we are investigating a group of C-type lectin-like antifreeze proteins from other fish species. 2. Other adaptive proteins: We provide the protein chemistry portion of a collaborative project in which a marine-source protein of economic value is being characterized.

Graduate Students

Gisela Martinez	PhD (co-supervisor: M. Litvak) Program
Elke Uribe	PhD Program

Lab Personnel

Robert Richards

Research Technician

Recent Publications:

Soanes, K.H., Ewart, K.V., Mattatall, N.R. (2008) Recombinant production and characterization of the carbohydrate recognition domain from Atlantic salmon C-type lectin receptor C (SCLRC) Protein Expr. Purif. Epub ahead of print: [PubMed]
Ewart, K.V., Williams, J., Richards, R.C., Gallant, J.W., Melville, K., Douglas, S.E. (2008) The early response of Atlantic salmon (Salmo salar) macrophages exposed in vitro to Aeromonas salmonicida cultured in broth and in fish Dev. Comp. Immunol. 32 :380-390 [PubMed]
Moffatt, B., Ewart, V. and Eastman, A. (2006) Cold comfort: antifreeze proteins. Phyisol. Plant. 126:5-16
Liebscher, R.S., Richards, R.C., Lewis, J.M, Short, C.E., Muise, D.E., Driedzic, W.R. and Ewart, K.V. (2006) Seasonal freeze resistance of rainbow smelt (Osmerus mordax) is generated by differential expression of glycerol-3-phosphate dehydrogenase, phosphoenolpyruvate carboxykinase and antifreeze protein genes. Physiol. Zool. 79:411-423 [PubMed]
Driedzic W.R., Clow, K.A., Short C.E. and Ewart, K.V. (2006) Glycerol production in rainbow smelt (Osmerus mordax) may be triggered by low temperature alone and is associated with the activation of GPDH and G3Pase. J. Exp. Biol. 209:1016-1023 [PubMed]
Walter, J.A., Ewart, K.V., Short, C.E., Burton, I.W. and Driedzic W.R. (2006) Accelerated hepatic glycerol synthesis in rainbow smelt (Osmerus mordax) is fuelled directly by glucose and alanine: a 1H and 13C nuclear magnetic resonance study. J. Exp. Zool. 305:480-488 [PubMed]
Rise, M.S., Douglas, S.E., Sakhrani, D., Williams, J., Ewart, K.V., Rise, M., Davidson, W.S., Koop, B.F. and Devlin, R.H. (2006) Multiple microarray platforms utilized for hepatic gene expression profiling of growth hormone transgenic coho salmon with and without ration restriction J. Mol. Endocrinol. 37:259-282 [PubMed]
Ewart, K.V., Belanger, J.C., Williams, J., Karakach, T., Penny, S., Tsoi, S.C.M., Richards, R.C. and Douglas, S.E. (2005) Identification of genes differentially expressed in Atlantic salmon (Salmo salar) in response to infection by Aeromononas salmonicida using cDNA microarray technology. Dev. Comp. Immunol. 29:333-347 [PubMed]
Hall, J.R., Richards, R.C., Maccormack, T.J., Ewart, K.V., Driedzic, W.R. (2005) Cloning of GLUT3 cDNA from Atlantic cod (Gadus morhua) and expression of GLUT1 and GLUT3 in response to hypoxia. Biochim. Biophys. Acta 1730:245-252 [PubMed]
Driedzic, W.R. and Ewart, K.V. (2004) Control of glycerol production by rainbow smelt (Osmerus mordax) to provide freeze resistance and allow foraging at low winter temperatures. Comp. Biochem. Physiol. 139:347-357 [PubMed]
Stratton, L., Wu, S., Richards, R.C. and Ewart, K.V. (2004) Oligomerisation and carbohydrate binding in a salmon serum C-type lectin consistent with non-self recognition. Fish Shellfish Immunol. 17:315-323 [PubMed]
Ewart, K.V. and Tsoi, S.C.M. (2004) Innate immune recognition of pathogens in teleost fish. pp. 82-116 In: Molecular aspects of fish and marine biology Volume III: Trends in the study of bacterial and viral fish diseases. K.Y. Leung and C.L. Hew (eds.), World Scientific Publishing: Singapore
Tsoi, S.C.M., Ewart, K.V., Penny, S., Melville, K., Liebscher, R.S., Brown, L.L. and Douglas, S.E. (2004) Identification of immune-relevant genes from Atlantic salmon using suppression subtractive hybridization. Mar. Biotechnol. 6:199-214 [PubMed]
Soanes, K.H., Figuereido, K., Richards, R.C., Mattatall, N.R. and Ewart, K.V. (2004) Sequence and expression of C-type lectin receptors in Atlantic salmon (Salmo salar). Immunogenetics 56:572-584 [PubMed]
Li, Z., Lin Q., Yang, D.S.C. Ewart, K.V. and Hew, C.L. (2004) The role of Ca2+-coordinating residues of herring antifreeze protein in ice binding. Biochemistry 43:14547-14554 [PubMed]

Last modified Thursday, 18th May, 2006 @ 11:09am