Listed below are the current projects available for biology and biochemistry honours students in the Storey Lab:
Escape to a state of torpor is essential to winter survival for many small mammals (we work on ground squirrels and bats). Animals strongly drop their metabolic rate (often to <5% of normal) and allow their body temperature to fall to near 0°C. We are interested in the gene controls involved. Multiple projects are available on two general themes: (1) epigenetic controls that regulate the strong global suppression of gene transcription: students will use immunoblotting to explore the posttranslational modifications (e.g. acetylation or phosphorylation) of histones and other proteins that control DNA transcription, and (2) hibernation-responsive gene expression: a few genes are strongly up-regulated during hibernation, most producing proteins that help to protect cellular macromolecules during torpor, and students can explore this process at multiple levels including signal transduction cascades, activation and nuclear translocation of transcription factors, use of PCR to measure gene-specific mRNA levels, and immunoblotting to analyze the levels of protein products.
Anoxia Tolerance: Enzymatic Regulation for Life Without Oxygen
Various animals endure long periods of oxygen deprivation in their natural environments. To enhance survival they conserve energy by strongly suppressing nonessential energy-expensive metabolic processes such as biosynthesis. Using animal models of anoxia tolerant turtles or snails, projects are available to explore the regulation of important enzymes that must be regulated under anoxia. Current interest is on enzymes that provide NADPH reducing power to drive various biochemical syntheses; these include glucose-6-phosphate dehydrogenase, isocitrate dehydrogenase, malic enzyme, and malate dehydrogenase. Projects involve protein purification techniques, spectrophotometric enzyme assay and kinetic analysis, immunoblotting, and a search for regulatory controls such as protein phosphorylation.
Many animals spend the winter frozen ! Up to 65% of their body water freezes as ice in extracellular compartments while multiple cryopreservation strategies are put to work to protect the intracellular environment. Using models of freeze tolerant frogs, turtles and snails, several projects are available that explore the transcriptional and translational regulation of cryoprotectant proteins. Studies can trace the signal transduction cascades that transmit freezing signals to the nucleus, analyze the activation and nuclear translocation of freeze-responsive transcription factors, use PCR to measure gene-specific mRNA levels, and apply immunoblotting to analyze the levels of specific protein products.
Insect Cold Hardiness
Winter survival for thousands of species of insects requires the synthesis of cryoprotectants that protect cells and their macromolecules from cold stress. Synthesis requires a massive seasonally-dependent redirection of carbohydrate flow to produce polyhydric alcohol cryoprotectants. Multiple projects in enzymology are available to examine the biochemical regulation of key enzymes in the biosynthetic pathway in our two model species of goldenrod gall forming insects. Projects involve protein purification, spectrophotometric enzyme assay and kinetic analysis, and a search for reversible phosphorylation controls that could provide on/off regulation.