Jesse Derby
Faculty Advisor: Anurag Agrawal
Year: 2021

“Observed Cardenolide Variation Amongst Milkweed Tissue and Its Physiological Effect on ATPase Activity”

Project Summary:

My project focused on chemical defenses within milkweed plants, involving questions of defense specialization, phytochemical diversity across tissue types within the same milkweed species, and the potential effects thereof. Phytochemical defense is crucial to the survival of many plant species, including those used for agricultural purposes such as tomato plants. A deeper understanding of its mechanisms within milkweed would not only improve our knowledge of that species, but could also prove relevant to the field of plant science as a whole.

In regards to methodology, the qualification and quantification of cardenolide compounds (the toxin milkweeds produce for their chemical defense) were done via HPLC analysis. Inhibitory effects were tested by performing sodium pump assays, in which activity of the pump was measured by the cleavage of free phosphate from supplied ATP in a given reaction buffer.

At the conclusion of the study, we found that phytochemical diversity exists within the different tissue types of Asclepias syriaca both in quantity and type of cardenolides. Furthermore, we also found that different cardenolides mixtures produced significantly different inhibitory effects, and that this variance differed for specialist insect herbivores.

These findings demonstrate that aspects of phytochemical diversity might play a crucial role in the evolution and specialization of phytochemical defense in milkweed species. And, if this is true for milkweeds, it is highly possible that other plant species share similar mechanisms of phytochemical defense and defense specialization, providing a framework that can be fully applied across the field of plant science.

My Experience:

I found my experience at BTI this summer extremely fulfilling, both professionally and personally. During the course of my study, I was exposed to topics in science I otherwise wouldn’t have learned about during my normal biomedical engineering classes. I received relevant experience both in the lab and in the field conducting scientific research, guided by mentors who supported me every step of the way. I always felt like my input was respected and taken in mind, even as an undergraduate who was new to university research. My mentors ensured that I participated in and learned about every step of the process during the study, all the way from sample collection through processing and data analysis. I would highly recommend anyone with a passionate interest in biological research, whether that be plant, animal, or human, to consider an internship at BTI.