Graduate Supervisors

The ecology of benthic invertebrates in streams and lakes, particularly the Laurentian Great Lakes. Responses to authropogenic disturbances, exotic species and changing land use. Monitoring and assessment of the affects of urban and agricultural development on the biota of streams.

Animal cell cultures are being used for three purposes: basic research, in vitro toxicology, and biotechnology. Basic research is being done on the development of differentiated fish cell lines and culture systems. These are used to identify and study the roles of nutrition, hormones and polypeptide growth factors on the growth and differentiation of fish tissues and organs. A particular point of interest is hemopoiesis. In the future these factors may be useful in enhancing the growth and health of fish. Some of the cell lines are being used in ecotoxicology studies. In particular the toxicology of dioxin-like compounds and polycyclic aromatic (PAHs) is being investigated. Many of these projects use current recombinant DNA and immunological technologies.

We use molecular genetics to probe the interactions of bacteria with their host organisms, focusing on the model Sinorhizobium meliloti / alfalfa interaction. We study soil and human microbiomes using functional metagenomics.

Plant cell and molecular biology: Cellular and molecular characterization of mechanisms controlling the structure and function of single-cell C4 photosynthesis in terrestrial plants. Major interests include characterizing the role of the cytoskeleton and its regulatory proteins in the movement of organelles and localization of macromolecules resulting in the establishment of cellular polarity in plant cells. We use a combination of approaches such as biochemistry, molecular biology, physiology, and cell biology including standard immunofluorescence and immunogold electron microscopy as well as the latest imaging techniques involving fluorescent-tagged proteins of living cells to investigate the research questions.

Theoretical and terrestrial ecology: Current ecological theory does a poor job of linking the physical environment to community processes. As a result there is a gap between ecosystem ecology and population/community ecology. This linkage is investigated in various systems of interest for conservation and management, such non-native forest pests, using both mathematical models and experiments. Current projects include development of new theory to predict the effects of species which modify the physical environment (ecosystem engineers), and production of accurate models of climate variability to predict extinction risk.

Molecular and functional characterization of fish immune systems, particularly Major Histocompatibility (MH) receptors and chemokines. Studying MH gene evolution through the molecular characterization of various fish populations. Effects of toxic chemicals on immune systems of aquatic organisms.

Effects of toxic chemicals on aquatic organisms, principally fish. Biotic modifying factors of toxicity. Development of methods for environmental effects monitoring. Physiologically based pharmacokinetic modelling of contaminant levels in fish.

Cancer-related cell cycle studies. My research is focused on characterizing protein factors that regulate the initiation of DNA replication, a key step in cell proliferation. The budding yeast Saccharomyces cerevisiae, is being used as a model organism, as it is one of the few eukaryotes for which numerous origins of replication have been identified. Many origin-associated protein factors have now been isolated from budding yeast. Human homologues of replication proteins originally identified in yeast have recently shown great promise as markers for potentially cancerous cell proliferation. Current work in the lab includes studying the Dbf4/Cdc7 kinase, which helps to trigger DNA replication by associating with origins and phosphorylating other origin-bound proteins, characterizing ORC (the origin recognition complex), and identifying novel origin-associated replication factors.

Isolation, characterization and manipulation of microbial genes which encode products that are involved in the microbial stimulation of plant growth. Biochemical and physiological consequences of genetically lowering plant ethylene levels. Microbial siderophore and phytohormone biosynthesis.

Photobiology and Photochemistry of xenobiotic contamination and ultraviolet radiation. The work addresses the impacts of sunlight on environmental biology and chemistry. The focus is on two projects: Photoinduced toxicity of environmental contaminants and effects of UV-B radiation on plants. These projects involve molecular, biochemical, photochemical, photobiological and whole organism techniques. The toxicology project deals with the impact of structural modification of contaminants after release into the environment. The environmental chemistry and toxicology of polycyclic aromatic hydrocarbons (PAHs) are under investigation as a model system to address these problems. The UV-B project is to assess the impact stratospheric ozone layer depletion on plants. The long range goal is the development of crop plants that are tolerant to elevated UV-B radiation and to probe the mechanisms of tolerance.

Applied aquatic ecology, paleolimnology, diatom algae. My research combines fields of aquatic ecology, paleoecology, hydrology and multivariate statistics to assess effects of multiple stressors (periodic floods & droughts, acidification, climatic variability & change, nutrients, species invasions) on lakes, wetlands and reservoirs. A focus is to improve our understanding of factors that regulate aquatic ecosystems at a multi-annual, whole-system scale. An additional focus is to quantify and predict ecosystem responses during degradation and recovery phases due to human disturbances and natural phenomena. Ongoing research projects assess effects of:

• climatic variability and river impoundment on hydro-ecological conditions of sensitive lakes and wetlands in the Mackenzie Basin Deltas (Peace-Athabasca Delta, Slave River Delta, MacKenzie River Delta) over the past 1,000 years. (Collaboration with Dr. Brent Wolfe [NSERC Northern Research Chair, Wilfrid Laurier U.], Dr. Tom Edwards [Earth Sciences, U. Waterloo], Dr. Peter Leavitt [U. Regina]; Dr. Bill Last [U. Manitoba] );

• interactions among acid deposition, climatic variability (drought) and wetlands on recovery of Ontario lakes from effects of acid rain (collaboration with Dr. Peter Dillon [NSERC Industrial Research Chair, Trent U.], Dr. Andrew Paterson [MOE, Dorset Environmental Science Centre] );

• human land use and climate on Lakes in Africa during the past 200 years (collaboration with Dr. Bob Hecky, Biology, University of Waterloo)

Our research goals are to understand the function and developmental regulation of small heat shock proteins (shsps) during early development. Shsps are molecular chaperones that are involved in stress resistance and cellular differentiation. Their synthesis has been associated with various disease states such as multiple sclerosis, Alzheimer’s disease and muscle myopathy. Recent studies in my lab using amphibian embryos have shown that members of the shsps are differentially expressed during development and that recombinant shsp can act as a molecular chaperone by inhibiting heat-induced protein aggregation. Examples of the methods used in our laboratory include gene cloning, RT-PCR, in situ hybridization, immunhistochemistry, microinjection of modified genes into embryos, molecular chaperone assays, site-specific mutagenesis, protein analysis etc.

Non-mendelian inheritance in plants: Molecular and genetic approaches are employed to understand how individual Arabidopsis thaliana plants can give rise to offspring that have distinct molecular profiles from those of the parent plant. Our research shows that the inheritance of non-parental markers occurs through a completely novel mechanism and suggests that these plants sequester a cryptic copy of ancestral genomic information. Research efforts focus on elucidating how Arabidopsis plants can give rise to this de novo genetic variation and whether these inbreeding plants harbor a genomic sequence cache.

Physiology and enzymology of hyperthermophilic archaea and bacteria: anaerobic and sulfur-dependent metabolism; function of dehydrogenases and flavoproteins; alcohol metabolism; relationship between structure and function of thermostable enzymes; protein engineering.

My research interests are centered around the molecular mechanisms that mediate changes in biological form. In particular I am interested in the modulation of cell adhesion states that allow for the complex three dimensional rearrangements that characterize early embryogenesis. These changes in adhesive state are under strict spatial and temporal control, and in many cases stem from extra-cellular signals that cells perceive in their immediate environment. My major line of research involve two families of cell adhesion molecules, the integrins, and the cadherins. Recent evidence indicates the regulation of adhesive states is through a direct cross-talk between these molecules, indicating a coordination between cell-matrix and cell-cell adhesion. This regulation of cell adhesion is not only found during early development but is also of fundamental significance to a wide variety of health related issues such as cancer and wound healing.

Environmental informatics research and international environmental information systems, especially as they relate to water issues. The use and applications of metadata to shared environmental information systems. Distance learning software and technology development for delivering courses on integrated water resource management.

Protein structure and function; bioinformatics and proteomics. Current research involves development of methods for the prediction of protein structure from amino acid sequence, using a combination of computational and biochemical techniques. Cross-linking data obtained from mass spectrometry is integrated into predictive algorithms, greatly reducing the problem complexity. Target structures include bacterial proteins inducible by antibiotic stress, and membrane proteins of unknown structure.

Plant molecular biology: isolation and molecular genetic analysis of mutants of Arabidopsis thaliana that are deficient in adenosine/adenine recycling some of which lead to defects in methylation. The role of these enzymes in plant development is being examined by genetic and biochemical analysis, metabolic profiling, protein interaction studies, immunolocalization, in situ hybridization, light and electron microscopy and creation of transgenic plants.

Biogeography, evolution and ecology of eukaryotic algae and the prediction of RNA secondary structure. My research is focused on the evolution, biogeography and ecology of marine and freshwater eukaryotic algae (primarily the Rhodophyta). These organisms play an important role in both freshwater and marine ecosystems. In particular, the rhodophyte subclass, Bangiophycidae, has been a primary focus in my laboratory. This subclass is believed to be the ancestral group from which the more morphologically complex red algal taxa have arisen and have played a pivotal role in the origin of plastids through secondary symbioses in the Cryptophyta, Haptophyta and Heterokonta. More recently we have been examining the invasion of eukaryotic algae (Bangia atropurpurea) and the distribution of green algae (Cladophora glomerata and Ulothrix zonata) within the Laurentian Great Lakes. My research program uses a combination of techniques to address biogeographic and taxonomic questions: analysis of conserved DNA sequences (nuclear and plastid SSU rRNA and rbcL genes), analysis of ultrastructural and morphological characteristics, karyology, seasonality studies, population genetics (ISSRs, RAPDs and AFLPs). In addition, my research focuses on the use and prediction of rRNA structure from sequence (covariation analysis) and the use of structure in taxonomic delineation.

Microbial communities are responsible for the biogeochemical cycling of trace gases, fertility of soils and aquatic environments, healthy function of the human body, metabolic production for the food industry, and countless applications in biotechnology. Despite a profound influence of microorganisms on human life and the global climate, very little is known about the distribution and diversity of microorganisms in natural communities, the vast resource of genes associated with the majority of uncultured microbial life, and the identities of most microbial species on earth: those adapted to life at low abundance.

My lab seeks to understand the causes of microbial diversity, the importance of diversity for ecosystem function, and the relationship between taxonomic and functional diversity. We discover new organisms and pathways involved in carbon and nitrogen cycling in soil and aquatic environments. We are developing new molecular methods to identify and characterise low-abundance organisms. Please contact me if you are interested in graduate work or postdoctoral opportunities in these areas.

Research activities focus on the conduct of inter-disciplinary programs in the areas of freshwater fisheries ecology and management and risk assessment. There is a special emphasis on the application of stable isotope techniques to the study of such issues. Current projects include collaboration with: [1] the Department of Fisheries and Oceans on an analysis of possible climate change effects on anadromous and lacustrine stocks of Arctic char, the analysis of trophic polymorphisms in Arctic char and comparative analysis of impacted lake foodwebs; [2] the University of Plymouth on the analysis of fish and invertebrate community structure change in British estuarine environments; [3] the Shannon regional Fisheries Board, Ireland, on a comparative trophic analysis sympatric Arctic char and brown trout populations; and [4] the Ontario Ministry of Natural Resources on telemetry studies of brow trout in the Credit River. Graduate students are currently working on aspects of caribou ecology using stable isotopes, validation of defensible methods for determining habitat alteration impacts on fish populations, determination of the impacts of water abstraction from small headwater streams on resident brook trout populations and macro-invertebrate communities and the use of stable isotopes to track contaminant impacts in aquatic foodwebs in northern Alberta.

Our lab uses green fluorescent protein (GFP)-based methods of live imaging in the model genetic organism Drosophila (the fruit fly) to study how cells are genetically programmed to die when they lose contact with their surroundings. The failure of this type of cell death – known as ‘anoikis’ – contributes to cancer metastasis and tumour invasiveness in humans. As a model system for anoikis we are studying the dynamics and interactions of the amnioserosa and the yolk membrane during embryonic development. One of the players in the interaction of these extraembryonic tissues during Drosophila development is basigin (Reed et al. , 2004: Current Biology 14 , 372-380), also known as EMMPRIN, which is a transmembrane integrin-associated glycoprotein. Mammalian homologues of basigin have established roles in tumour invasiveness but also function as a part of normal embryo implantation.

Structural Studies of Glycoside Hydrolases
This major area of research involves enzymes that recognize and act upon carbohydrates, including especially glycosidases involved in the protein glycosylation pathway and the process of starch digestion.
Current projects include:
- Human intestinal glucosidases involved in deriving glucose from starch. These are potential targets for controlling blood glucose  and insulin levels.
- Glycosidases from bacterial flora, for example from the mammalian gut microflora or from environmental samples
- Mannosidases and other enzymes involved in building the carbohydrate structures on glycoproteins. These are potential therapeutic targets for cancer and infection.

Biosystematics of Asters, Goldenasters and Goldenrods (Fam. Asteraceae) and phylogeny of the Tribe Astereae. Historical phytogeography, multivariate morphometrics, cytotaxonomy and chemosystematics used to resolve evolutionary histories. Ecology of rare plants.

Please contact directly for information.

Freshwater ecology with emphasis on primary producers and their interactions with natural and anthropogenic environmental factors. Effects of climate change (especially concerning ultraviolet radiation, organic and inorganic contaminants, and invasive species in aquatic ecosystems. Plankton and environmental assessment.

Calcium channels participate in brain functions, such as synaptic transmission, neuronal plasticity, patterned nerve activity underlying rhythmic behaviours, outgrowth of neurons and synapse formation. Actively seeking graduate students.

Aquatic ecology, including nutrient dynamics, planktonic food webs, stream ecology, and the fate of bacteria in lakes and rivers.

Membrane biochemistry and molecular biology: the molecular basis of membrane deterioration in aging tissues; plant membrane-hormone interaction; comparative aspects of senescence and stress including the role of hormones and the involvement of free radicals; molecular cloning of genes involved in senescence and stress.

A major research goal of my lab is to elucidate the neural mechanisms that support planning: the ability, shared by humans and many animals, to take the consequences of one's actions into account when making a decision.  How can brains do this? A key element of planning is the ability to predict the outcome of a particular course of action. What representations and computations in the brain support this prediction? How are these learned and used in specific situations? By studying planning in behaving rats, we can record neural and chemical signals from the brain, observing these processes "live" as rats learn and make decisions. Advancing our understanding of the brain in this way requires a confluence of ideas and tools from different disciplines, including psychology, neuroscience, computer science/machine learning, and engineering. Projects in the lab focus on experimental, theoretical/computational, and engineering goals; students interested in a combination of these are especially encouraged to apply.

Characterization of the adaptive responses to stress in animals: the molecular and biochemical strategies exhibited at the cellular level, the specificity of the signaling and cellular transduction responses, and the integration of such responses at the organismal level. Specific projects include, stress proteins and their role in the cellular stress response; environmental effects on cortisol dynamics; toxicant effects on the early-life stages; environmental and hormonal effects on energy metabolism. The applied aspect of the research will be in the development of molecular and biochemical probes for stress/toxicant detection.

Microbial Biotechnology: microbial growth and production of enzymes and primary metabolites: fungal morphology; biotransformations using cells and soluble enzymes; development of advanced fermentation methodology; process development and technology transfer, studies relating to growth, product formation and stability of recombinant microorganisms.

Application of molecular markers to address questions related to the ecology and evolution of aquatic organisms. A central theme that is currently being addressed in my lab concerns the reasons for, and consequences of disparities between rates of evolution at the molecular morphological and morphological levels. To address these issues, we employ both population and species level comparative approaches. The lab is also engaged in research related to conservation, and the use of molecular methods for the diagnosis of species boundaries.