Alumnus Profile: Cheryl Hayashi SM ’88: “From Science Hill to Spider Silk Studies”

Cheryl Hayashi SM ’88 (Ph.D. ’96), a 2007 MacArthur Fellow, has had a lifelong curiosity about nature. She was exposed to a great diversity of life while growing up in Hawaii, a place she calls a “living laboratory of evolution.”

It is not surprising that when she stepped onto Yale’s campus, biology was on her short list of possible majors. However, she had never really considered a career as a professor until a summer research experience taught her that professors do much more than teach.

Seeing their passion for research, she remembers thinking that “what grad students and professors did was the coolest thing.” She loved the idea of exploring unanswered questions.

During her time as an undergraduate, Hayashi got a campus job feeding a spider colony in a lab on Science Hill. She admits that she had never been very fond of arthropods: “I was not the kind of kid that grew up collecting bugs and spiders and things. I have to confess that I was a bit squeamish about them.”

The time she spent hand-feeding the spiders Drosophila and crickets gave her an excellent opportunity to get to know the lab’s principal investigator, Dr. Catherine Craig. Before long, Hayashi became so interested in the work that she joined the lab to do research for her senior thesis.

This led to an opportunity to travel with the professor as a research assistant in the field. Hayashi spent the summer after her senior year in Panama; to her, the experience felt “like a paid vacation.” She naturally began asking questions about the organisms in front of her, and those questions developed into a fascinating research career.

Now an Associate Professor of Biology at the University of California, Riverside, Hayashi lab is currently working on several projects, it focuses on characterizing spider silks by performance and molecular structure. Hayashi initially thought the research would encompass only several questions and would thus be completed in a few years.

She quickly learned, however, that the subject was much more complex than she had ever imagined. Each type of spider produces several different silks, and each silk is composed of a unique set of proteins. She describes spiders as little engineers; they use their different silks, each exhibiting unique mechanical properties, for different tasks.

The diversity among silks never ceases to amaze her. The species of spider in the popular children’s book Charlotte’s Web alone makes seven kinds of silk, and many of the other 40,000 described species are similarly complex.

One research team cannot conquer the vast world of spider silks, but the Hayashi lab is certainly doing its part. The lab characterizes complete genes for different silks, including working with some spider families that have never been studied before.

Hayashi describes looking at a new DNA sequencing result as her favorite part of the research, for “you realize you’re the first person looking at that silk gene. It’s like having a little secret between you and the spider.”

Hayashi’s work has many potential applications. As the mechanical properties of the strong, lightweight silks often surpass those of manmade materials, the characterization of the silk structures could lead to exciting new material science technologies in medicine, industry, law enforcement, and defense.

Moreover, spider silks are made of proteins and are therefore biodegradable. Materials modeled after silks would be both useful and easy to dispose of, which is becoming increasingly more important in the today’s environmentally-conscious community.

Hayashi says these potential applications show her the clear value of biodiversity. Spiders have been evolving for hundreds of millions of years and have adapted to varied and extreme environments including aquatic habitats, deserts, arctic regions, and rainforests. If we can utilize the design principles that have been fine-tuned by nature over so many years, we can create newer, better materials that can withstand virtually any ambient condition.

Hayashi realizes that new questions and discoveries could completely change the focus of her lab’s work, and is therefore not quick to say for certain the directions her research will take. She does hope to see some of the material science applications of her research put into practice, and she would also like to better understand the underlying behaviors and morphology behind spiders’ utilization of different silks for various tasks.

A more personal goal is to serve as a mentor to undergraduates just as a Yale professor did for her. To this day, she traces her research roots to her days of feeding spiders on Science Hill. Hayashi encourages students to find opportunities to spend time in the lab because you “just never know where life and research are going to take you.”