Fish Can Be Friends!

By Sakina Shahid, Summer Research Intern in Dr. Nishad Jayasundara’s Lab

Pictured are my three wristband solvent extracts. I did the wristband extractions in the Stapleton Lab guided by Dr. Heather Stapleton

I have always been terrified of encountering or touching fish. But, that’s beginning to change after spending a summer interning in the Jayasundara and DiGiulio labs working alongside these little vertebrates. During my time here, I conducted research on using zebrafish as a model for testing the toxicity of chemical extracts from silicone wristband.

Yes, the silicone wristbands given out at concerts or events are becoming an increasingly popular tool for capturing the mixture of chemicals we are exposed to on a daily basis. The silicone material acts as a porous layer that absorbs organic compounds such as PAHs, flame retardants and pesticides. Not only are wristbands cost effective, they are also non-invasive compared to traditional urine or blood sampling methods. However, exposure alone does not explain biological outcomes. When linked with the field of toxicology, we can begin to understand the mechanisms by which exposures impact health.

Zebrafish, or Danio rerio, are a whole organism model used to study human health and disease. They share 70% of their genetic code with us and organs such as kidney, liver, heart and brain are conserved across species. Their high fecundity (they produce many offspring) allows for high throughput screening and they reach adulthood within 3 months of birth. By developing a method through which zebrafish are exposed to environmentally relevant mixtures from wristband extracts, we can gain insight into how environmental mixture exposures may be impacting our health.

I delved into this method development process under the guidance of Ilaria Merutka, a 4th year PhD candidate, and Melissa Chernick, the lab manager. They taught me all the skills I needed – ranging from fish husbandry and breeding, to micro pipetting and washing my glass petri dishes. Some mornings and afternoons, I was scheduled for fish care, an intensive routine where you check water quality, pH, clean tanks, and harvest live brine shrimp for feeding. I became more comfortable being around fish through this process, and now see them as lab pets. I grappled with the ethics of using live animals for research and the plastic waste produced by labs daily. Ilaria’s approach to these questions resonated with me, where she prioritizes the health of the animal during its life & recognizes the implications of its sacrifice for science and human health at large.

I tested the toxicity of wristbands collected in a previous firefighter exposure study conducted by Levasseur et al, using a behavioral assay. The machine called Danio Vision measures the locomotion of zebrafish larvae under light and dark conditions. Locomotion in fish gives us insight into several physiological functions such as nerves, energy, motor coordination and neurodevelopment. Hypoactivity (less active) relative to the control can indicate anxious behavior or lack of response to stimulus whereas hyperactivity may indicate increased risk taking behavior, making the larvae more susceptible to predation in the wild.

What left me feeling the most inspired was seeing the collaboration between labs and scientists. I was struck by everyone’s willingness to extend their resources and knowledge despite having so much on their plate already. The field of environmental health sciences are facing increasingly complex challenges, requiring equally elaborate and ingenious answers. I like to think that environmental science, more so than other fields, encourages such collaboration because our lived environments are naturally integrated and connected. I found the lab’s problem-oriented approach to science refreshing, where folks are constantly molding their expertise to the problem at hand and picking up new skills along the way. After the summer, I am excited to continue working on my Masters Project in the Jayasundara Lab for the upcoming school year!