Résumé

Looking Under the Hood

Physicist David Altman is moved by myosin. We all are.

Myosin is a motor protein. Responsible for every conscious and unconscious flex of our muscles, it beats our hearts.

Altman wants to understand how the molecular motor works — how the roiling action inside of a cell affects myosin's function. In 2012, Altman spent his junior sabbatical at McGill University in Montreal, Canada, performing an experiment that tested competing theories about muscle fibers’ unusual mechanical properties. The results of his experiment were published April 16 in PLoS ONE.

Muscles and Motors

Muscles have an odd and poorly understand behavior. Normally, an active muscle is stiff, because its proteins interact and form connections. But when an active muscle is used in a cyclic fashion — think of your heart beating or leg muscles when you’re running — the muscle temporarily becomes softer. When the cyclic motion stops, the muscle stiffens again.

This temporary softening, called thixotropy, may be connected to our posture. Stiff muscles provide support when you sit in class, but become less stiff and more limber when you run. The mechanism of thixotropy in muscles is not well understood, though Altman suspected that myosin was the key.

At the heart of muscle fibers are two types of interlocking filaments: myosin filaments — which contain hundreds of myosin motors that tie themselves together — and actin filaments. In active muscle, myosins bind to actin. Myosins make muscles contract by pulling themselves, stroke by stroke, along the actin filament.

Loosening Up

Altman wanted to test whether the interaction between actin and myosin was responsible for muscle’s thixotropy. According to this model, muscles’ cyclic motion breaks the actin-myosin attachments and makes the muscle fiber softer. Once motion stops, it takes a little while for myosin to re-bind to actin and make the fiber stiff again.

Altman’s experiment involved disrupting actin-myosin interactions and vibrating the muscle fiber at different frequencies to measure its stiffness. Using two chemicals that prevent myosin binding to actin, Altman then tested the muscle. The loosening effect vanished.

“To people who study muscle, it was a debate as to what was responsible for thixotropy,” says Altman. ”The experiment indicates that muscles’ stiffness depends on myosin’s grip.”

Next Steps

The experiment revealed another, unknown process at work. When the cyclic motion was slow enough, Altman was surprised to find that the muscle fiber no longer softened; it became stiffer, or rheopectic. Altman suspects thixotropy depends on forces from molecules jostling within the crowded cellular environment, but no one knows how or why muscles would stiffen when subjected to low frequency vibration.

Through Willamette’s Senior Research Seminar course and through the Science Collaborative Research Program, students work with Altman to learn more about myosins’ cellular function. “In my lab, we study myosins inside cells as opposed to just purified myosins, because we want to understand physiologically relevant conditions and how they affect the motor,” says Altman.

Over the summer, he’ll move his myosin-trapping laser lab to the basement of Collins Science Center. In the fall, Altman will continue working with physics majors on their theses, while looking for more collaborative research opportunities to explore the enigmatic muscular motor protein.

Letter from the governor

 

To support enrollment efforts, I worked with the Office of the Governor to secure a personalized welcome for admitted students.

In particular, students from smaller cities and towns indicated that this was an impactful communication that reinforced the university's distinctive location across the street from the Oregon State Capitol. 

Media response to sexual assault concerns

When a fraternity's private Facebook posts were published anonymously, members of the campus community expressed serious concerns about messages' misogynistic content. 

After the local paper published a story—including photos of students' signs—journalists flocked to campus. The Portland NBC affiliate was one of many outlets that covered the issue:

The incident sparked discussions about sexual assault, campus climate and Title IX. 

In addition to developing a robust understanding of these issues through associated research and discourse, I was moved by stories from people involved and wanted to help address the need for men to become more engaged. I sought out formal training from the Association of Title IX Administrators, and I serve as an investigator and hearing panel member for related conduct cases. 

 

 

My passion: Understanding science

I shared the following column, which ran on March 11, 2013, as part of the "My Passion" series in our local newspaper. 

Growing up in Las Vegas with parents that insisted I venture out into summer’s sandy oven, I spent a lot of time catching scorpions, vinegaroons and all kinds of reptiles. I marveled at the way each creature seemed perfectly suited for its place — and its prey. 

I’ve seen blood squirt from the eyes of a horned lizard, and I’ve dropped a desert iguana when distracted by the whip of its separated, writhing tail. One of my best friends can attest to the wallop a small sidewinder packs.  

Despite all the time I spent exploring and experiencing the desert, it wasn’t until a college trip with friends to Zion National Park, far from the electric skies of Las Vegas, that I looked up and saw the Milky Way - the band of stars that form the “backbone of night.” I felt the bewildering immensity of nature for the first time.

I still wonder what our ancestors thought as they gathered around a fire pit and looked to the sky. Some of their answers became myths that shaped and were shaped by society, but what of the countless millions who weren’t satisfied by such explanations? Among the everyday struggle for survival, there must have been people like me — people for whom the echoing question, “What are stars?” would never be silenced.

Human nature is to seek understanding. Our minds are powerful, complex but imperfect pattern detectors. When we look at clouds, we see shapes. We impose meaning on randomness. We confuse correlation and causality. We infer intent by default, and because we are biased to reinforce our own beliefs, it takes effort to overcome an incorrect idea that has taken root. 

These biases served us well through millennia. We survived. 

Through science, we’ve opened a window to the heavens, and we’ve looked back in time to discover much about how we came to be. 

I was stunned to learn that nearly half of Americans don’t know how long it takes our planet to revolve around the sun. I cringe when politicians deny evolution. My heart breaks when children die from easily preventable or treatable conditions because parents decide against vaccines or choose prayer over medicine.

Though science has certainly demonstrated its value to our health, economy and quality of life, it is more than advanced technology or medical treatments. The scientific method is humanity’s best tool to discover truth.

I started the local Science Pub series in conjunction with OMSI, and I collaborate with scientists to help share their work with the public. I’m passionate about the public understanding of science not just because I love the mysteries of quantum mechanics, neuroscience and cosmology, but because scientific literacy affects our ability to evaluate important issues facing our society.

With our growing population, its commensurate impact, our advancing technological sophistication and proliferation of ideas and claims, we need decision makers who understand the value and methods of science. We need a scientifically literate electorate that is able to face with open eyes our economic, environmental and geopolitical challenges.

I’m passionate about the public understanding of science not only because it answers the question, “What are stars?” but because I believe that the truth is the best foundation upon which to build our future.

Value infographic

Cited by a prominent financial aid consultant as one of the best communications in higher ed, I created this piece (with the help of an in-house designer and writer) to help shift the college cost conversation to a university value conversation.

Designed originally to strengthen the university’s website, the infographic was heavily used in print enrollment marketing campaigns and in admission fairs to quantify key competitive advantages and to counter prospective students’ perceptions about the value of a liberal arts education.

The Scene concept

The university magazine theme and cover concept was based on Willamette's less known places, activities and talents. A friend and chemistry professor created a scale model of Waller Hall, one of the university's iconic buildings.