May 6-15th is Science and Technology Week in Canada. The Canadian Rivers Institute (CRI) uses the occasion to profile some of its work to advance cutting-edge technology in aquatic research.
CRI’s Stable Isotopes in Nature laboratory (SINLab) at UNB in Fredericton uses Continuous Flow Isotope Ratio Mass Spectrometry to analyze stable isotopes of carbon, nitrogen, hydrogen and sulphur in a variety of plant and animal materials. SINLab is one of the few stable isotope labs in Canada with a research focus on ecology. CRI’s Environmental Chemistry Lab at UNB Saint John analyses biota and sediments for mercury, other metals and elements, polycyclic aromatic hydrocarbons (PAHs), select pesticides, and polychlorinated biphenyls (PCBs). CRI’s fish ageing laboratory utilizes a precision diamond saw to section calcified ageing structures enabling identification and assessment of fish health based on life history characteristics.
Ecogenomics is another area that CRI is playing a prominent role in advancing new technological tools to the field of aquatic sciences. Ecogenomics is the cloning of specific genes to produce a profile of diversity in an environmental sample - water or soil. Many CRI researchers are experts in this field, including Science Directors Dr. Chris Martyniuk, Dr. Donald Baird, and Dr. Scott Pavey and Associate Dr. Mehrdad Hajibabaei.
Dr. Chris Martyniuk, based in the Department of Physiological Sciences and College of Veterinary Medicine at the University of Florida, and his research team of three graduate students and two post-doctoral fellows, leverages the emerging field of “Big Data” – datasets so large and complex that they require new approaches for analysis and generate a wealth of information. In Martyniuk’s research, these approaches use the latest in genome sequencing technologies to capture the full scope of molecular responses of fish to contaminants, particularly historically used and new pesticides.
Dr. Martyniuk has a variety of research projects underway, for example projects to develop in vitro approaches to study stressors in largemouth bass eggs and livers for contaminant screening; studying the effects of polycyclic aromatic hydrocarbons on the reproductive axis in fish; determining the impact of environmental contaminants on the fish microbiome; evaluating the impact of pesticide exposures on mitochondrial function in fish eggs and dopamine cells; and molecular network analyses of chemicals.
In order to evaluate his research questions, Martyniuk uses a number of state-of-the-art technologies to collect massive datasets that can be mined for genomics information.
“It has revolutionized how we view organismal responses,” says Martyniuk. “Being able to generate new information about an organism by using a single technology has enabled us to learn so much more, more quickly and efficiently.”
For example, Martyniuk explains that these technologies allows him to learn more about what a chemical is doing in the whole animal, and broadens the scope of what he can understand. New pathways that are perturbed by chemicals can then be identified and studied in more detail.
“We use instruments to conduct our gene expression and microbiome research to understand adverse outcomes in aquatic organisms. For example, what responses on a molecular level predict decreased reproductive output or increased stress,” he explains.
One of the instruments is a mass spectrometer, which measures a significant number of proteins and metabolites at once in a fish tissue or cell. A second instrument used is a ‘Seahorse’, “not the Seahorse that hides in seaweed,” he jokes, but an instrument that measures oxidative respiration in cells, tissues or embryos.
These techniques allow Martyniuk to produce information to build molecular networks, which generates novel insight into fish physiology.
“We are showing that some chemical compounds, such as pesticides, inhibit the mitochondrial bioenergetics in fish embryos, which could have detrimental impacts on early development. If animals are no longer producing sufficient amounts of the ‘energy molecule’, adenosine triphosphate or ATP, this may manifest as delayed hatching success for fish,” says Martyniuk.
“ATP is the form of energy required for all living cells to survive. If ATP levels are depleted, then cells can no longer function efficiently and will either cease to grow or die resulting in a cascading effect on the organism itself, the food web, and the health of the river ecosystem,” explains Martyniuk when asked about the implications of these findings. He explains that largemouth bass in Florida are continuously restocked into the springs and river systems, as there is poor recruitment of this apex predator every year. One reason may be that eggs and fry show low survival in the water.
Martyniuk’s work is also about understanding the potential linkages to human health impacts. “At the molecular level, fish responses and those of humans are actually quite comparable, as chemicals can affect the same cell pathways. Understanding fish responses can give us some insights into how human development may be impacted by pesticide exposure,” he says.
Prior to his current position at the University of Florida, Martyniuk held a Canada Research Chair in Molecular Ecology at the University of New Brunswick in Saint John. There, he was appointed to the CRI Science Director Board and collaborated with fellow Science Director, Dr. Karen Kidd, and one of CRI’s founding members, Dr. Kelly Munkittrick. His early work at CRI based at UNB Saint John built the strong foundation and world-class credibility needed to attract a new CRI collaborator, and new Canada Research Chair, Dr. Scott Pavey, who, in conjunction with Martyniuk, Baird and Hajibabaei, continues to push the genomics research and its application to aquatic science.
