Category Archives: Graduate

Helping to Solve the Plastic Apocalypse

By: Juan Pablo de los Rios

Hello! My name is Juan Pablo (JP) de los Rios and I was honored to have been selected as a Norma and Jerol Sonosky Environmental Sustainability Fellow this past summer. I am a first–year chemistry graduate student working with Professor Megan Fieser. The Fieser group’s primary focus is solving what is a leading problem in environmental pollution: plastics. Consumers have abused the applications and use of plastic polymers to the point that plastics are projected to outweigh all fish in the sea by 2050! It is factual that our dependence on single–use plastics has far exceeded exploitation. Thus, we must propose alternative routes to diminish this exploitation and restore the environment’s stability.

These are some plastic pollutants collected by the Fieser Group at Hermosa Beach through the Heal the Bay: Adopt–A–Beach Initiative.

These are some plastic pollutants collected by the Fieser Group at Hermosa Beach through the Heal the Bay: Adopt–A–Beach Initiative.

One possible route is to create new polymers that can mimic the properties of those currently produced, while also being degradable. For example, we want to create degradable plastic products that can handle larger fluctuations in temperature or become more flexible and ductile without breaking. For these alternative plastics to be synthesized we must be able to effectively transform the smaller building blocks, or monomers, into the larger polymer chains. These transformations, or polymerizations, occur with the use of metal catalysts. This last summer I have been primarily focusing on synthesizing and characterizing a series of organic ligands that provide support and reactivity to a metal center in a catalyst (rare–earth metals, in particular). Furthermore, I began optimizing reactions to create the metal catalysts that will be capable of polymerizing the monomers into polymers.

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These are two organic ligands that I synthesized, characterized, and optimized! I plan on reacting these with lanthanide metals to create my catalysts and eventually begin polymerization reactions.

The second route to solving the plastic apocalypse is to efficiently recycle those that are sitting in landfills or floating in the oceans. The methods used presently to recycle plastics are far from effective. For example, only 2% of plastic water bottles will be recycled into a plastic water bottle again! Therefore, the Fieser group is currently focusing on developing metal catalysts that are capable of transforming, or depolymerizing, the larger polymer chains back into their respective monomers. The best part is that we plan on screening the organic ligands synthesized from the polymerization reactions, but with different metals (alkaline earth metals) to investigate their reactivity for depolymerization. Both of the discussed avenues will help create both environmentally sustainable and cost–effective processes that will reduce the global contamination of plastic materials.

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This is a normal day at the Fieser lab. Our air–sensitive chemistry requires proper use of both the Schlenk line (left) and glovebox (right).

It is truly difficult to define our science as strictly organic or inorganic. The Fieser group takes a multidisciplinary approach to create catalysts for our chemical transformations. Thus, members of the Fieser group experience and utilize the techniques and skills of organic and inorganic synthesis. These include isolation and purification methods of our ligands, as well as air–sensitive chemistry in the glovebox and Schlenk line when synthesizing metal complexes.

The Fieser group is a brand–new research group currently situated at the Loker Hydrocarbon Institute but soon moving to our new space in Seeley G. Mudd Building. We are more than excited for our research endeavors and the possible collaborations and contributions that we will bring to USC! Please stay updated with our group website: https://dornsifecms.usc.edu/labs/fieser/

Finally, I would like to acknowledge and sincerely thank Norma and Jerol Sonosky for their generous support in my sustainable research. I have been capable of focusing my time and attention into progressing these alternative avenues that will, hopefully, lead us into a cleaner future. Thank you for reading!

 

Domesticating the Wild Kelpie

By: Kelly DeWeese

Hi! My name is Kelly DeWeese, and I’m a second year graduate student in the Molecular Biology PhD program at USC. I research Macrocystis pyifera (giant kelp) in the Nuzhdin Lab, where we are working toward giant kelp domestication for growth in open ocean aquaculture. In our lab we nickname giant kelp “Kelpie”, like the fearsome Celtic sea monster made out of kelp featured in recent Harry Potter movies:

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Source: https://www.talenthouse.com/i/1521/submission/326356/e948dbdf

This summer I was awarded the USC Wrigley Summer Fellowship to do lab work and collect kelp on Catalina. My project is focused on using transcriptomic analyses to learn more about the genes involved in giant kelp reproductive pathways.

Transcriptomics uses data on mRNA (read: gene) expression to analyze which genes are being expressed in different conditions, at different times of day, etc. We are interested in the reproductive pathway because as part of the domestication process, our lab wants to sterilize (i.e. knock out the reproductive pathway of) the kelp that is farmed because it will be growing in the ocean, not in a controlled environment. A transcriptomic analysis that will help us understand the reproductive pathway is a differential expression analysis of both reproductive and nonreproductive giant kelp tissues. Comparing the genes that are differently expressed between each tissue type will highlight some candidate genes involved in reproduction that can be knocked out or selected for in domesticated giant kelp to sterilize the organism.

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Most days on the island, my undergrads, Ben and Jean, and I go out and collect sporophyte tissue growing near the ocean’s surface in the morning. Ben drives the boat, and Jean and I take punches of kelp blades and put them on in seawater, on dry ice or in preserving solution for transport back to the lab. Here some labmates and I are taking a Boston whaler to collect giant kelp off the coast of Catalina Island:

Screen Shot 2019-08-21 at 9.03.47 AMThen, Ben, Jean and I take the giant kelp samples back to the lab for homogenization and extraction of RNA. This summer we worked on optimizing a protocol to extract clean RNA in high concentrations, which is difficult because giant kelp has thick cell walls and cells full of macromolecules that contaminate RNA extractions. Last week, my undergrads presented on their research at the USC Wrigley REU Symposium to wrap up their time out on the island. Thanks for such a great summer and all your hard work, Ben and Jean!