By Ariel Root

“Something that’s important to note about nanoparticles, is that it’s more than just their size; they’re also special. There’s something special about them: they have greater surface area; they have interesting electronics; they glow. There’s always something different about a nano-material that makes it separate from just a small amount of the bulk.” Maria DeRosa, TEDxĐÓ°ÉÔ­´´ U, 2010.

From her graduate school days, Maria DeRosa has been interested in developing novel bionanotechnology, called aptamers, for detecting molecular targets of relevance to health. “Nano science and nano tech are looking at ways to apply these technologies to important problems. So…how can nanotechnology help?”

DeRosa is an Associate Professor in the Department of Chemistry and Institute of Biochemistry, and also works in collaboration with government researchers from Agriculture and Agrifood Canada, Health Canada and Environment Canada, as well as industrial partner and farmer groups. Her educational training as a material scientists during her doctoral years at ĐÓ°ÉÔ­´´, combined with her post-doctoral work determining how DNA works in the body, as well as an external sensor, prepared DeRosa with the necessary skills to work with aptamers.

An aptamer is a small single-strand of DNA or RNA sequences that bind specifically to a variety of target molecules, and therefore have many environmental, agricultural, and health applications. Specifically, aptamers can be bound to neurotransmitters, allowing inflow of dopamine into the brain, but can also increase delivery efficiency of fertilizers into plants. DeRosa is interested in the use of aptamers for the design of novel bionanotechnology related to biosensing and catalysis.

DeRosa has long had an interest in research that provides understanding of bionanotechnology at the molecular level, but at the same time has tangible benefits beyond expanding knowledge, and the scientific community. When DeRosa started her faculty position at ĐÓ°ÉÔ­´´, she was introduced to the health impacts of mycotoxins.“These secondary metabolites that are produced by fungi can be widespread on crops and food commodities. I realized that developing low cost, easy-to-use technology that detects these contaminants in food would be a worthy pursuit and could have a global impact on health,” resulting in her pursuit of developing aptamers for mycotoxins in food.

“We need food because food gives us the energy, and it gives us the nutrients and building blocks that we need in order for our cells, our proteins, and our tissues, to function…it’s central to us, and to our health.” Ingestion of mycotoxins from foods can cause cancer or stunting, and can affect both humans and animals. In the Canadian context, detection of these toxins is performed in a laboratory setting, though aptamers could enable farmers to test on site; a helpful and economical tool. In the developing world however, mycotoxins are a health crisis, and the ability to accurately detect mycotoxins is not always available in any sort. “We need to be able to detect these toxins in cheapest, and most practical, way,” which means farmers need to be able to perform these tests on site, and in the field. For instance, DeRosa shows a USB flash-drive sized stick, and explains that the farmer would grind up some grain, mix with a bit of water, and place a droplet onto the sensor. If mycotoxins were present, a small plus sign would appear—similar to a pregnancy test.

DeRosa explains that the key is to make the aptamers cost-efficient while maintaining accuracy. “Aptamers have to be specific, and we can’t have false negative, or false positives. They have to maintain accuracy at low levels.” However, many hurdles persist regarding aptamer design and the complexities of food matrices. “In pure water, even low-end versions can find a toxin. But in food, there are proteins, and bacteria… the tough part is the intricate mix [within a food].” DeRosa has successfully created an aptamer that will bind to norovirus in meat sources, but she indicates that each food has a unique matrix of components, and therefore aptamer design has to be reinvented and redefined for each toxin and food source. In a lab, tests can clean, separate, or count components of the food, “but at the farm or grain elevator, or in a developing country… that’s the challenge.”

DeRosa indicates that she has “wonderful students and colleagues who keep [her] inspired and driven.” She is particularly interested in developing ideas in collaboration with her students and colleagues, who have all helped to define specific problems, or specific foods, as related to aptamers. Together, she enjoys developing a solution. “I don’t know if I’ve had an impact outside of the scientific community yet, but I’m hopeful that one is coming.” DeRosa recalls that her research group was one of the first to apply aptamers to food and agricultural problems, “… and now I see that many other research groups are also working in this area. I hope that soon all these efforts (in our group and others) will pay off in the form of technology that can be applied outside of the lab and in the real world.”

For Dr. DeRosa’s contact information, go here.

An eider nest is surveyed near Cape Dorset by a team of hunters and researchers from Environment Canada and ĐÓ°ÉÔ­´´ University studying the effects of disease and predation on nesting birds.

By Jennifer Provencher, Department of Biology, ĐÓ°ÉÔ­´´ University

A striking step forward in environmental protection policy was the creation of the Minamata Convention signed by 128 countries in 2013. As of April 2015, ten countries had ratified the convention. The Convention aims to limit the release of mercury into the environment. Although mercury is naturally found in the environment, it is also released by a number of industrial processes. Methyl mercury is a known neurotoxin that affects animal development and reproduction. The most extreme example of mercury poisoning for humans is from Minamata, Japan (where the convention’s name comes from). The people of Minamata were exposed to mercury through industrial wastewater from a nearby chemical factory in the mid-1950s. The mercury released into the sea bioaccumulated in the shellfish and fish in the area, which were main food staples for the local residents. Feeding on this seafood resulted in acute mercury poisoning, causing a severe neurological disorder among humans now known as Minamata disease.

Although the Minamata Convention is potentially a huge win for environmental protection, there is much work to be done. First, there is the task of ratification by each participating country, which must alter their national legislations to align with the Minamata Convention. Once all the new legislation is in place, countries must then have programs and enforcement in place to ensure that stakeholders are compliant with the policies on release and disposal of mercury. And there is still the task of designing and implementing monitoring programs to evaluate whether the steps put into place are in fact having the desired effect of reducing mercury in the environment and in wildlife. One stage for this environmental play is the Canadian Arctic.

In the Canadian Arctic, mercury in many habitats and species has been studied, with samples from water and plankton through intermediates in the food chain up to polar bears and humans. Some of the most extensive data sets on mercury are available for animals in the Canadian Arctic, which allows researchers to study how mercury is changing in the environment over time. Seabirds have been particularly useful as study species for researchers who are interested in the effects of mercury, and the overall trends of mercury in northern ecosystems. Environment Canada researchers and its National Wildlife Specimen Bank, located on ĐÓ°ÉÔ­´´ University’s campus, have played an important supporting role in this research. Several marine birds have shown that mercury levels in the Canadian Arctic have increased since the 1970s, and continue to rise in some areas (^{Riget et al.; Science of the Total Environment doi:10.1016/j.scitotenv.2011.05.002}). A recent study looking at specimens dating back to the 1800s show that some bird species that are high in the Arctic food chain are experiencing a 45 fold increase in mercury over the last century (^{Bond et al. 2015; The Royal Society 10.1098/rspb.2015.0032}). This increase contrasts with decreases seen in persistent organic pollutants in seabird tissues following policy measures over a much shorter time frame: from the 1970s to present (^{Braune et al. 2010; Interdisciplinary Studies in Environmental Chemistry}).

Hunters return to home with eider ducks after a day of spring hunting. Samples are taken from the birds to study parasites and contaminants, and then the Hunter and Trapper Association distributes the meat among the community.

Studying and measuring mercury in marine birds each year socio-cultural perspectives. Marine birds are an integral part of both traditional culture and modern practices in northern Canada. Their eggs are collected for food during the breeding season and duck and goose down is a valuable insulating material that continues to be collected today by many for both personal use and commercial sales. Marine birds are also hunted for their meat, and their skins are used for household items such as slippers, bowls and jackets. Currently, there are many concerns in the north including rising food costs, sustainability, healthy food choices, and the need to better integrate traditional knowledge with science for ensuring viability of harvested populations. It is hard to argue with the value of marine birds as traditional foods: they are after all free range, organic, sustainable, locally grown, locally harvested, healthy to eat and grounded in cultural practices. Marine birds continue to have very low levels of mercury making birds like geese and ducks (along with caribou and other country foods) great sources of healthy, local nutrition. It is perhaps not happenstance that they are also used as ‘sample sentinels’ for studies on possible changes in pollutant levels of importance to human health.

An eider skin basket made by the Fur Production and Design class at the Nunavut Arctic College in Iqaluit as part of their annual wildlife workshop.

There are other reasons why we should be ‘keeping an eye’ on mercury in Arctic marine birds. The story of mercury cycling in the environment is much more complex than can be captured by a single international agreement. Mercury levels in northern Canada are not influenced by North American emissions, but have the potential to be greatly influenced by those from Asia. Even with the Minamata Convention in place, emissions from some regions in Asia are not predicted to slow for decades, and even when they do, it may take decades to cease increasing levels in Arctic ecosystems (^{Provencher et al. 2014; Environmental Reviews dx.doi.org/10.1139/er-2013-0072}). One only has to go to smog-filled streets of Beijing to see how distant the Canadian Arctic is. Additionally, warming trends in the north that are causing the melting of glaciers and permafrost may be releasing large quantities of mercury into the environment. The low productivity of the Arctic may also make top-level predators susceptible to bioaccumulating more mercury than their counterparts in ecosystems with higher productivity . Thus, arctic marine birds in Canada may be particularly at risk from increasing Hg levels associated with long-term Hg deposition patterns and changing climatic conditions.

Schematic of how a system with low productivity with slow growing biota may lead to exacerbated mercury burdens in top predatorsas compared with more productive, faster growing systems

Canada still needs to ratify the Minamata Convention and research is needed to continue to monitor mercury in marine birds and northern ecosystems. Through these studies, we can help determine if any policies put in place are leading to the desired outcomes (a reduction in environmental mercury). These studies also will help us understand both the acute and sub-lethal effects of mercury on organisms. This research can continue to contribute to other conversations around human health and sustainability in the Arctic, and be used to engage northern students in science, building capacity and helping people make informed decisions (^{Provencher et al. 2013; Arctic}). So although legislators have succeeded with an international agreement on mercury, it is the continued work on mercury and marine birds that has the potential to help inform and evaluate policies and also to shape education, health and culture.

Based on Provencher, J.F., Mallory, M.L., Braune, B.M., Forbes, M.R., Gilchrist, H.G., 2014. Mercury and marine birds in Arctic Canada: effects, current trends and why we should be paying closer attention. Environmental Reviews 22, 244-255.