Fish Reproductive Physiology Lab
Dr. Glen Van Der Kraak
B.Sc. – University of Manitoba
M.Sc. – University of Manitoba
Ph.D. – University of British Columbia
Multifactorial Regulation of Ovarian Function in Teleosts
Fish are used as the experimental model for studies investigating how the actions of hormones, growth factors of ovarian origin and intracellular signal transduction pathways interact to coordinate ovarian growth and differentiation. While our studies in the past used goldfish and rainbow trout our most recent work focuses on the zebrafish so that we can exploit the daily spawning in order to characterize the temporal sequence of endocrine changes that accompany oocyte final maturation and ovulation. We study the control of growth, atresia and hormone biosynthetic capacity of zebrafish ovarian follicles during the period of oocyte maturation and at ovulation. In addition, we are addressing the relevance of growth factors to ovarian physiology (IGFs, steroids, retinoids) by studying their actions and assessing of their sites of synthesis within the ovary and regulation of their production.
Evaluation of Reproductive Fitness in Fish
Awareness that chemicals in the environment affect reproductive performance of feral fish populations through effects on endocrine homeostasis has led to the implementation of industrial process changes and waste treatment strategies designed to eliminate or reduce the release of harmful chemicals to the environment. As a result, there is a need to develop rapid methods of determining the effectiveness of technological changes as they pertain to reproductive endocrine endpoints. On going research focuses on the development of short term in vitro techniques through to whole animal test methods applicable in lab and field settings to evaluate both general reproductive physiology through to the effects seen following exposure to chemicals on reproductive physiology of fish. The long term goal of this work is to establish whether chemicals which are identified on the basis of in vitro bioactivity are predictive of effects in vivo and to determine which endocrine responses are most sensitive in terms of whole animal and population levels effects. Our traditional focus has been on the effects of pulp and paper and sewage effluent discharges but one of the new areas where we are working relate to the impacts associated with exposure to wastes generated during the processing of the Alberta oil sands. We also have with collaborators at the University of British Columbia and the Department of Fisheries and Oceans been studying the underlying mechanisms responsible for early migration and high levels of pre-spawning mortality in several stocks of Fraser River sockeye salmon (Oncorhynchus nerka).
Ecotoxicological Effects of Atrazine on Amphibians
Atrazine is a widely used herbicide that is applied to corn sorghum and sugar cane crops. There is concern that amphibians may be exposed to atrazine as a result of run-off to waterbodies in the vicinity of agriculutural land following application the herbicide. There is concern that atrazine may function as an endocrine disruptor and adversely effect reproductive development in amphibians. With a consortium of researchers in the Canada, the United States and South Africa, we are investigating the effects of atrazine on various aspects of reproductive development in both lab and field settings
B.Sc. – University of Guelph
M.Sc. – University of Guelph
The research I conduct focuses on the impact of human activities on the health and reproductive fitness of fish. We study the effects of a variety of complex mixtures and targeted compounds, including effluent released by wastewater treatment facilities, effluent from the manufacture of pulp and paper and pesticides found in agricultural runoff. Using zebrafish as a model species, we examine the effects of these compounds at a molecular level using qPCR and enzyme immunoassay and link molecular changes to an adverse outcome like reduced spawning success.
B.Sc. – McMaster University
M.Sc.- McMaster University
My research focuses on the role of prostaglandins in the periovulatory period of the zebrafish ovary. Prostaglandins are a group of lipid compounds involved in inflammation and ovulation, whose function is highly conserved across vertebrate taxa. I use various molecular techniques to examine how gene expression and protein levels change during ovulation and the role played by prostaglandins in this process. Additionally, I am investigating the impact that environmental contaminants such as pharmaceuticals, can have on this process.
B.Sc. – University of Guelph
I will be investigating the role of microRNAs in reproductive physiology. MicroRNAs (miRNAs) are small non-coding RNAs that regulate gene expression primarily at post-transcriptional levels. While there is evidence that miRNAs play an important role in regulating ovarian function in mammals, there is little knowledge of their role in fish. Using bioinformatics and lab techniques, I will attempt to characterize miRNAs that are important regulators of maturation, folliculogenesis and steroidogenesis in the zebrafish ovary. Furthermore, I will examine the effects of wastewater effluent on reproductively relevant miRNAs.
Former Graduate Students
Hailey Hunter, M.Sc.
Thesis title: Tumor Necrosis Factor alpha and Ovulation in the Zebrafish (Danio rerio) (2018).
Abiran Sritharan, M.Sc.
Trevor Partch, M.Sc.
Courtney McDermid, M.Sc.
Cory Schilling, M.Sc.
Madelyn Cosme, M.Sc.
Olivia Knight, M.Sc.
Richard Kavanagh, Ph.D.
David Irwin, M.Sc.
Nick Melnyk, M.Sc.
Thesis title: Regulation of prostaglandin synthesis in the zebrafish ovary (2011).
Meghan Fuzzen, M.Sc.