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. – Rutgers, The State University of New Jersey-New Brunswick
Ph.D. – University of Toronto
I’m a post-doc in the lab. I received my PhD from university of Toronto in molecular genetics. I am interested in using pluripotent cells to study the effect(s) of environment on mammalian development. More precisely I use embryonic stem cells to model the molecular events which occur upon exposure to environmental chemicals.
B.Sc. – McMaster University
My interests in research are centered on reproductive endocrinology. My current Master’s project looks at the presence of a corticotropin-releasing-factor (CRF) signalling system within Zebrafish ovarian tissue. Although there’s a good deal of characterization of similar systems in mammals, comparatively little ground work has been done in teleosts. At present, results suggest the ov-CRF system works to inhibit gonadotropin-induced steroidogenesis in the developing ovarian follicle, though a great deal of work remains in understanding when this system is activated, and the ultimate result of its activity
B.Sc. – University of Guelph
Peroxisome proliferator activated-receptors (PPARs) are nuclear transcription factors, which in mammals are critical regulators of ovarian follicle development and steroidogenesis. PPARs are thought to act downstream of the Luteinizing hormone (LH) surge via the regulation of genes involved in ovulation and the steroid synthesis pathways. However, little to no information exists on the role of PPARs in the ovarian tissues of teleosts. Therefore, the goal of my research is to examine the expression and function of PPARs in zebrafish ovaries.
B.Sc. – University of Guelph
My graduate work is currently focussed on looking at the role that the immune system may play in the zebrafish ovary and determining whether or not immune regulators are involved in ovulation. There are currently a number of gaps in our understanding of how ovulation is controlled in fish and immune regulating genes may play an important role in this process. It has been demonstrated that immune regulators are important in mammals and so I am interested in how important these regulators are during ovulation in fish.