Anne Todgham
Lab Phone: 805 893 6176
Email Address: todgham@lifesci.ucsb.edu

My research interests aim to examine how variations in an animal’s natural environment are transduced through its genotype to ultimately impact performance.  I am fascinated by the interplay between an animal’s environment and the organism’s physiological plasticity to respond to environmental change. 

A few questions I think about:

  • What is the ecological significance of physiological plasticity?  To what capacity do organisms inhabiting a variable environment utilize this plasticity? Is this plasticity sufficient to “buffer” the effects of a rapidly changing global environment?

  • As temperature is one of the key abiotic factors influencing organismal distribution, how does an animal’s thermal history integrate with immediate fluctuations in their natural environment to structure their physiological response to environmental change?  Does the influence of thermal history vary between eurythermal and stenothermal organisms?

  • What components of an animal’s transcriptome (mRNA transcripts) are entrained by the predictable nature of the environment and what are the underlying mechanisms that regulate this?

  • How do gene expression and protein profiles shift with fluctuations in an organism’s natural environment?  Is there disconnect between increased expression of a particular gene and an increase in the associated protein?  What is the significance of transcriptional vs. post-transcriptional regulation of particular pathways in organisms living in variable environments?

In my PhD thesis I focused mainly on the role of temperature in modulating the heat shock protein response of an intertidal sculpin.  The majority of my field research was conducted at the Bamfield Marine Sciences Centre in tidepools where my research questions addressed the temporal and spatial variability of the thermal environment and the related plasticity in the Hsp response.

During my first two years in the Hofmann Lab as a Natural Sciences and Engineering Research Council of Canada postfoctoral fellow, I used both biochemical and genomics approaches to look more comprehensively at the physiological constraints imposed by an animal's natural environment. My research focused on the molecular physiology of cold-adaptation in Antarctic fish species, specifically the mechanisms underlying how these animals are able to maintain integrity of the cellular protein pool at subzero temperatures. Although cold-denaturation of proteins is well documented, the consequences of inhabiting a subzero environment and defending protein homeostasis are poorly understood. While these fish have many adaptations that provide them with impressive resistance to the cold (e.g. antifreeze proteins), the stable subzero Antarctic environment may be more perturbing to the formation and maintenance of native protein structures than once thought. The focus of our investigations is to understand how Antarctic fish cope with cold-related protein damage and misfolding, as well as to more broadly understand how gene expression may have been altered in Antarctic fish as an adaptation to near-freezing temperatures. Through comparison with their cold temperate New Zealand relatives, Antarctic notothenoids provide us with an ideal opportunity to determine if traits of these fish represent an adaptation to the sub-zero Antarctic environment or whether the traits are related to history and are characteristic of the notothenoid lineage.

Currently, my research focuses on the use of transcriptomic-based approaches (microarrays and quantitative PCR) to examine the potential implications of climate change for marine organisms. Specifically, I am investigating the genome-level response to ocean acidification (OA) in the developing larvae of the purple sea urchin, Strongylocentrotus purpuratus. As the research community explores the impact of OA on marine ecosystems, a key link to forecasting the effects of this altered seawater chemistry is an understanding of the response at the organismal level. Since the response is likely to be complex and involve several cellular and molecular mechanisms, we are hoping to leverage genomics tools to better understand the physiological responses to OA. What stands to be gained from this approach is an understanding of the direct impacts of OA and whether organisms have sufficient physiological plasticity to adapt to the altered CO2 conditions. It may also be a powerful tool to explore the synergistic effects of OA and altered seawater temperatures that also will be a consequence of global climate change. While it is unclear which aspects of an animal's physiology will be impacted by OA, by targeting candidate pathways that we would predict might be altered, we can begin to address how this change in environmental conditions will be felt at the organismal level in terms of performance, tolerance and ultimately fitness. I have designed a custom oligonucleotide "boutique" microarray for purple urchins that is designed to screen the expression patterns of genes central to the calcification process, acid-base compensation and ion regulation, cellular stress response, apoptosis, cell cycle, development, metabolism, translational control of proteins and cell signaling. Presently, I am using this tool to identify potential "weak links" in physiological function that may prevent an organism from tolerating any additional acidification of their marine environment. Recent work demonstrates that pathways other than calcification are impacted greatly, suggesting that overall physiological capacity and not just a singular focus on biomineralization processes is essential to our understanding of the costs and consequences of living in a high CO2 ocean.

Publications

Todgham, A.E. and Hofmann, G.E. 2009. Transcriptomic response of sea urchin larvae Strongylocentrotus purpuratus to CO2-driven seawater acidification. Journal of Experimental Biology (In press).

Mandic, M., Todgham, A.E. and Richards, J.G. 2009. The evolution of mechanisms of hypoxia tolerance. Proc. R. Soc. B 276:735-744.

Hofmann, G.E., O’Donnell, M.J. and Todgham, A.E. 2008. Using functional genomics to explore the impacts of ocean acidification on calcifying marine organisms. Mar. Ecol. Prog. Ser. 373:219-225.

Sloman, K.A., Mandic, M, Todgham, A.E., Fangue, N.A. and Richards, J.G. 2008. The response of the tidepool sculpin, Oligocottus maculosus, to hypoxia in laboratory, mesocosm and field environments. Comp. Biochem. Physiol. A 149:284-292.

Todgham, A.E., Hoaglund, E.A. and Hofmann, G.E. 2007. Is cold the new hot?: Elevated ubiquitin conjugated protein levels in tissues of Antarctic fish as evidence for cold-denaturation of proteins in vivo. J. Comp. Physiol. B 177:857-866.

Todgham, A.E., Iwama, G.K. and Schulte, P.M. 2006. Effects of the natural tidal cycle and artificial tempeature cycling on Hsp levels in tidepool sculpins, Oligocottus maculosus. Physiol. Biochem. Zool. 79: 1033-1045.

Todgham, A.E., Schulte, P.M. and Iwama, G.K. 2005. Cross-tolerance in the tidepool sculpin: the role of heat shock proteins. Physiol. Biochem. Zool. 78:133-144.

Iwama, G.K., Afonso, L.O.B., Todgham, A.E., Ackerman, P.A. and Nakano, K. 2004. Are hsps suitable for indicating stressed states in fish? J. Exp. Biol. 207:15-19.

Basu, N., Todgham, A.E., Ackerman, P.A., Bibeau, M.R., Nakano, K., Schulte, P.M. and Iwama, G.K. 2002. Heat shock protein genes and their functional significance in fish. Gene 295:173-183.

Todgham, A.E., Anderson, P.M., and Wright, P.A. 2001. Effects of exercise on nitrogen excretion, carbamoyl phosphate synthetase III activity and related urea cycle enzymes in muscle and liver tissues of juvenile rainbow trout (Oncorhynchus mykiss). Comp. Biochem. Physiol. A 129: 527-539.

Gamperl, A.K., Todgham, A.E., Parkhouse, W.S., Dill, R. and Farrell A.P. 2001. Recovery of trout myocardial function following anoxia: preconditioning in a non-mammalian model. Am. J. Physiol. 281: R1755-1763.