Academic Degrees

Ph.D. Zoology, Zoological Institute of Russian Academy of Sciences, St. Petersburg, Russia (1997)

B.S. Biology, St. Petersburg State University, St. Petersburg, Russia (1991)

Professional Experience

Courses Taught

BIOL 2111 Cell Biology Lab
BIOL 3144 Ecology
BIOL 3144L Ecology Laboratory
BIOL 4600 Senior Seminar
BIOL 4000/5000 Ecotoxicology
BIOL 6000/8000 Ecotoxicology
BIOL 6000/8000 Environmental Toxicology and Health

Feodor Lynen Fellowship

Ecological Physiology and Adaptation in Marine Poikilotherms

The overarching theme of my research is a study of physiological mechanisms of environmental adaptation and stress tolerance in marine poikilotherms. In today’s world, geological forces have combined with past and present human activities to cause an extremely rapid environmental change, one that is often too strong and too fast to permit the long process of evolutionary adaptation that can require many generations to complete. The population survival and distribution of many species in this rapidly changing environment will depend on their abilities to cope with stress and to quickly adjust their physiology to environmental change. 

We use experimental and comparative approaches in order to understand how environmental stressors such as temperature and heavy metal pollution may limit survival and distribution of marine invertebrates. Understanding of the physiological mechanisms and limitations of stress tolerance is crucial for the understanding of the fate of populations of poikilotherms, which comprise >95% of marine animal biodiversity, in the face of the global environmental change.

Models
We use marine mollusks (oysters and snails) as models for our research. They are common organisms in marine coastal ecosystems, and their physiology and genetics is fairly well known to make them useful model objects; in fact, they are quickly becoming aquatic counterparts of the fruit fly.

Current research projects

Effects of heavy metals and temperature on bioenergetics of marine poikilotherms.
This project is focused on understanding of the effects of environmental temperature (such as expected in case of the global climate change) and heavy metals on bioenergetics of marine poikilotherms.  We use oysters as model species to investigate the effects of these environmental stressors on mitochondria, which are main powerhouses of the cell and provide ATP to fuel all energy-dependent cellular processes. We study how temperature and heavy metals affect ATP production, proton leak and efficiency of oyster mitochondria, which consequences the mitochondrial changes have for the whole-organism physiology and metabolism, and which physiological and cellular mechanisms allow oysters to keep their energy balance positive (i.e. to match their energy demand with energy supply), which is required for survival and ultimately adaptation under conditions of the environmental stress.

Molecular mechanisms of proton leak
Proton leak is a key factor determining efficiency of mitochondria and affecting basal metabolic rate of the organism (i.e. the energy cost an organism has to pay just for staying alive). "Leaky" mitochondria mean higher basal metabolic rate and more energy needed for the organism's maintenance. Many environmental stressors (including temperature and heavy metals) can increase proton leak in mitochondria. However, the mechanisms of proton leak are not well understood. We use molecular techniques to analyze gene expression of uncoupling proteins and adenine nucleotide transporter, which are thought to be responsible for mitochondrial proton leak, in oysters exposed to elevated temperatures and heavy metals, in order to gain a better understanding of the proton leak mechanisms and regulation.

Evolution of mitochondrial involvement in apoptosis
If you are still not fully convinced that mitochondria are fascinating organelles, here is the final proof: not only they provide us all with energy, they also play a key role in a host of other cellular processes including intracellular signaling and programmed cell death, also called apoptosis or cell suicide. Apoptosis is a fundamental process in multicellular organisms, which is required to sculpt organs and tissues, adjust cell numbers, and eliminate potentially dangerous or superfluous cells. In collaboration with the laboratory of Dr. F.M. Hughes we study molecular mechanisms of programmed cell death in marine invertebrates, the role of mitochondria in heavy metal-induced apoptosis and links between mitochondrial bioenergetics and cell suicide. Our study aims to provide novel insights into the role of mitochondria in regulation of the cell suicide in invertebrates and elucidate the link between heavy-metal induced apoptosis and immunodeficiency in oysters.

Mitochondrial function in exercise: Fitness Freaks versus Couch Potatoes
Our lab collaborates with Dr. Lightfoot (Dept. of Kinesiology, UNCC) on a study, which aims to understand genetic determinants of exercise endurance in mice and to determine the specific genes involved in the control of inherent exercise endurance. Our lab will compare mitochondrial function in two different strains of mice, one that is genetically predisposed to strenuous exercise and one that consists of lazy "couch potatoes" in order to understand whether metabolic physiology of these strains is adjusted and contributes to their exercise endurance. Understanding the genetic factors that predispose an individual to a certain fitness level could lead to better methods of improving the physical health and well-being of individuals. 

From the field to the lab... And back in the field again!
Although a fair bit of our research is done in the lab using biochemical, molecular and cellular techniques, the ultimate goal of our studies is to understand the effects of environmental stressors at the whole organism level and the consequences, which it can have for the field populations experiencing stress in their natural habitats. Therefore, our laboratory studies are tightly linked with the studies of animals in their natural habitats. We compare animals from different environments (e.g. warm and cold, polluted and unpolluted) in order to see how our lab predictions hold in the field. Click here for snapshots of our field and lab endeavors.

The People

Funding:
NSF
NIH
North Carolina Sea Grant
US Department of Agriculture
Alexander von Humboldt Foundation

Biographical Sketch

Selected Recent Publications

Click here for the complete publication list

[*Indicates a student co-author]

Sokolova I.M., Lannig G. (2008). Interactive effects of metal pollution and temperature on ectotherm metabolism and their implications for the global climate change in aquatic ecosystems. Climate Research (in press).

Ivanina A.V.*, Habinck E.*, Sokolova I.M. (2008). Differential sensitivity to cadmium of key mitochondrial enzymes in the eastern oyster, Crassostrea virginica Gmelin (Bivalvia: Ostreidae). Comparative Biochemistry and Physiology C 148: 72-79. http://dx.doi.org/10.1016/j.cbpc.2008.03.009

Ivanina A.V.*, Sokolova I.M. (2008). Effects of cadmium exposure on expression and activity of P-glycoprotein in eastern oysters, Crassostrea virginica Gmelin. Aquatic Toxicology 88:19-28. http://dx.doi.org/10.1016/j.aquatox.2008.02.014

 Ivanina A.V.*, Sokolova I.M., Sukhotin A.A. (2008). Oxidative stress and expression of chaperones in aging mollusks. Comparative Biochemistry and Physiology A 150: 53-61. http://dx.doi.org/10.1016/j.cbpb.2008.01.005

Lannig G., Bock C., Cherkasov A.*, Pörtner H.O., Sokolova I.M. (2008). Cadmium-dependent oxygen limitation affects temperature tolerance in eastern oysters (Crassostrea virginica Gmelin). American Journal of Physiology - Regulatory, Integrative and Comparative Physiology  294:1338-1346. http://ajpregu.physiology.org/cgi/reprint/294/4/R1338

Ivanina A.V.*,  Cherkasov A.S.*, Sokolova I.M. (2008). Effects of cadmium on cellular protein and glutathione synthesis and expression of stress proteins in eastern oysters, Crassostrea virginica Gmelin. Journal of Experimental Biology 211: 577-586. http://jeb.biologists.org/cgi/reprint/211/4/577

Sanni B.*, Williams K.*, Sokolov E.P., Sokolova I.M. (2008). Effects of acclimation temperature and cadmium exposure on mitochondrial aconitase and LON protease from a model marine ectotherm, Crassostrea virginica. Comparative Biochemistry and Physiology C 147: 101 - 112.  http://dx.doi.org/10.1016/j.cbpc.2007.08.005

Cherkasov A.S.*, Grewal S.*, Sokolova I.M. (2007). Combined effects of temperature and cadmium exposure on haemocyte apoptosis and cadmium accumulation in the eastern oyster Crassostrea virginica (Gmelin). Journal of Thermal Biology 32 (3): 162 - 170.

Cherkasov A.S.*, Overton, R.A. Jr*, Sokolov E.P., Sokolova I.M. (2007). Temperature-dependent effects of cadmium and purine nucleotides on mitochondrial aconitase from a marine ectotherm, Crassostrea virginica: a role of temperature in oxidative stress and allosteric enzyme regulation. Journal of Experimental Biology 210: 46-55. http://jeb.biologists.org/cgi/reprint/210/1/46
Featured on "Inside JEB" http://jeb.biologists.org/cgi/reprint/210/1/ii 

Lannig G., Flores J.F., Sokolova I.M. (2006). Temperature-dependent stress response in oysters, Crassostrea virginica: Pollution reduces temperature tolerance in oysters. Aquatic Toxicology 79: 278-287.

Cherkasov A.S.*, Ringwood A.H., Sokolova I.M. (2006). Effects of cadmium exposure on mitochondrial function are modulated by acclimation temperature in eastern oysters Crassostrea virginica Gmelin (Bivalvia: Ostreidae). Environmental Toxicology & Chemistry 25: 2461-2469.

Lannig G., Cherkasov A.S.*, Sokolova I.M. (2006). Temperature-dependent effects of cadmium on mitochondrial and whole-organism bioenergetics of oysters (Crassostrea virginica). Marine Environmental Research 62: S79-S82.

Sokolova I.M., Oliver J.D., Leamy L.J. (2006). An AFLP approach to identify genetic markers associated with resistance to Vibrio vulnificus and Perkinsus marinus in eastern oysters. Journal of Shellfish Research 25: 95-100.

Cherkasov A.S.*, Biswas P.K., Ridings D.M., Ringwood A.H., Sokolova I.M. (2006). Effects of acclimation temperature and cadmium exposure on cellular energy budgets in a marine mollusk Crassostrea virginica: Linking cellular and mitochondrial responses. Journal of Experimental Biology 209:1274-1284.

Sokolova I.M., Leamy L., Harrison M.*, Oliver J.D. (2005). Intrapopulational variation in Vibrio vulnificus levels in Crassostrea virginica (Gmelin 1971) is associated with the host size but not with disease status or developmental stability. Journal of Shellfish Research 24: 503-508.

Sokolova I.M., Ringwood A.H., Johnson C.* (2005). Tissue-specific accumulation of cadmium in subcellular compartments of eastern oysters Crassostrea virginica Gmelin (Bivalvia: Ostreidae). Aquatic Toxicology 74: 218-228. http://www.sciencedirect.com/ (doi:10.1016/j.aquatox.2005.05.012)

Sokolova I.M., Sokolov E.P., Ponnappa K.M.* (2005).Cadmium exposure affects mitochondrial bioenergetics and gene
expression of key mitochondrial proteins in the eastern oyster Crassostrea virginica Gmelin (Bivalvia: Ostreidae). Aquatic Toxicology 73: 242- 255. http://www.sciencedirect.com/

Sokolova I.M., Sokolov E.P. (2005). Evolution of mitochondrial uncoupling proteins: Novel invertebrate UCP homologues suggest early evolutionary divergence of the UCP family. FEBS Letters 579: 313-317 http://www.febsletters.org/article/PIIS0014579304015340/abstract 

Sokolova I.M., Evans S.*, Hughes F.M. (2004). Cadmium-induced apoptosis in oyster hemocytes involves disturbance of cellular energy balance but no mitochondrial permeability transition. Journal of Experimental Biology 207: 3369-3380.  http://jeb.biologists.org/cgi/reprint/207/19/3369

Sokolova I.M. (2004). Cadmium effects on mitochondrial function are enhanced by elevated temperatures in a marine poikilotherm, Crassostrea virginica Gmelin (Bivalvia: Ostreidae). Journal of Experimental Biology 207: 2639-2648.  http://jeb.biologists.org/cgi/reprint/207/15/2639.pdf

Sokolova I.M., Boulding E.G. (2004). A neutral DNA marker suggests that parallel physiological adaptations to open shore and salt marsh habitats have evolved more than once within two different species of gastropods. Marine Biology 145: 133-147

Sokolova I.M., Boulding E.G. (2004). Length polymorphisms in an intron of aminopeptidase N provide a useful nuclear DNA marker for Littorina species (Caenogastropoda). Journal of Molluscan Studies 70: 165 - 172.