The Johns Hopkins Gazette: May 15, 2000
May 15, 2000
VOL. 29, NO. 36


Scene on Campus

2 p.m.
Thursday, April 27

Johns Hopkins Gazette Online Edition

Brace yourself and take a deep breath. Somewhere in the Homewood campus's Macaulay building, an annual rite of spring has started, and the undergraduates have their hands on some heavy-duty research equipment.

"They're always a little timid when they first start using the scanning electron microscope and the other equipment," says Evangelos Moudrianakis, biology professor.

Through a Howard Hughes grant for developing new curricula, Moudrianakis is teaching a course, Form and Function, dedicated to teaching students how to prepare samples and examine them through various kinds of microscopes.

When spring and its accompanying burst of greenery hit campus, students from the course gather plant samples and sign up to bring them to the SEM with Moudrianakis, who shows them how to scan their samples from different angles and at varying magnifications. Students also can take pictures, save them to disk, alter and amend their images on the computer and print copies.

Moudrianakis also encourages students from a plant biochemistry course he teaches to sign up for the SEM exercise. He uses the images to bring the material from his course to vivid life. "I'm hoping to give the students a better appreciation of how the biology issues I'm teaching them in class are related to the more biophysical aspects of form and structure," he explains.

The hands-on experience also helps students get a feel for the challenges and rewards of structural analysis, and the preview it provides has convinced a few students to switch their graduate study goals to include such projects.

At the lab today, a group of four students is a little tense. Moudrianakis is anything but. They affectionately tease each other all afternoon, but Moudrianakis is by far the one who scores the most zingers.

Alton Etheridge, a junior in biology, is the first to use the SEM. Moudrianakis shows him how to adjust the view of a preloaded fruit fly, and then when Etheridge captures an aesthetically satisfying perspective on the fly, Moudrianakis shows him how to take a picture. He guides Etheridge through the steps of adjusting contrast and brightness, as well as loading, exposing and developing the film.

Meanwhile, in a room across the hall, the others are getting samples ready for the SEM by cutting small, thin pieces of the plants and mounting them with a special glue on a small metal stage about the size of a shirt button.

When their samples are ready and approved, students place them in a chamber that coats the top of the samples with a layer of gold and platinum 1 atom thick. The metal helps reflect the stream of electrons beamed at the sample stage inside the microscope's vacuum chamber, and these reflections produce the image.

When Ruby Kim, a senior in neuroscience, has her tiny flower, smaller than a dime, loaded into the vacuum chamber at the heart of the SEM, Moudrianakis turns away and says, "All right, Ruby, it's your operation."

"Oh no, I need help," she replies.

"You're beyond help," he teases, but immediately moves to show her the right controls.

Kim gets even later, when Moudrianakis misremembers a student's name, but later still she praises Moudrianakis' ability to explain the intricacies of science.

"He's so good with analogies," she says. "If you don't understand him the first time he tries to explain it; he can often go right into a different analogy."

Lisa Centeno, a senior in public health/natural sciences, emphasizes how rare it is to have a chance as an undergraduate to operate a piece of equipment like the SEM.

"We get many opportunities to use light microscopes, and that's interesting, too, but nothing to compare to this," Centeno says.

The images are astonishing. Centeno's small plant buds contain a view that, outside of the fact that it was etched entirely in shades of lime green, could easily be mistaken for an Impressionist painting of gentle plant-flecked hillsides beside a tranquil lake. When she zooms in even closer, though, a strange profusion of ropelike hairs is revealed.

At the center of her flower, Kim finds an image suggestive of the latest aliens-ate-my-brains melodrama from Hollywood: a melee of stretchy octopoid arms that, she says, "seem like they're reaching for me."

Moudrianakis reaches for an old SEM photo of a fruit fly and points out how the lower part of its face bears a striking resemblance to a certain short, green-skinned, pointy-eared mentor figure from the Star Wars movies.

"Look!" he cries. "It's Yoda!"

Crystal Hayes, a senior in natural sciences, finds both impressionistic views and Hollywood horror movie perspectives, including a skull-like cellulose framework at the edge where she cut the plant's stem.

Continued scanning reveals pollen grains like peanuts, flecks of soil like boulders, mushroomlike structures known as anthers and surface openings known as stomata.

Bizarre revelations abound.

Plants, for example, are much more hirsute than everyday experience would lead one to expect. There's quite a bit of hair on branches, stems, buds and even flowers. It's a plant's way of making itself less palatable to animals, Moudrianakis explains. Also, the hairs can provide a velvety finish to blossoms by reflecting light unevenly.

Another big surprise: Blades of grass have thorns. They're plainly visible on the SEM as long, thin spears that stick right up between the rows of cells that form the plane of a blade of grass.

Connections to and demonstrations of the students' classwork also keep popping up, from the acid-emitting cells at the head of a tap or main root, which helps clear the way for other smaller roots, to examples of how the stomata close up in dry conditions.

At the end of the afternoon, the students take home on computer disks electronic image files of the strange panoply of microscopic vistas that they have seen.
--Michael Purdy