Give Bacteria Their Shape
Data May Help Drug Makers Develop Antibiotics
That Work in a New Way
Conducting research that may pave the way for a new type of
antibiotic, a Johns Hopkins undergraduate student has been
testing a newly discovered protein filament that bends a
bacterium into a distinctive banana shape.
Using lasers, an electron microscope and other high-tech tools, Laura Rupprecht, a junior biomedical engineering major, is studying the properties of crescentin, an intermediate filament discovered in 2003 and thus far found only inside the bacteria called Caulobacter Crescentus. Rupprecht, 21, is from St. Paul, Minn.
Her work, funded by an undergraduate research grant from the university, focuses on cytoskeletal proteins such as crescentin. These strands form a web-like network inside a bacterium, giving it shape and helping it to move and divide. In some of her experiments, Rupprecht has used a laser to disable part of a cell's crescentin filament network, and then has recorded how quickly the network reconstructs itself.
"All bacteria have cytoskeletal structures," she said. "If someone can develop a new type of antibiotic that attacks these proteins, it could disable or kill the bacteria. But first, we have to figure out how the cytoskeletal structure works. Our experiments are a first step in doing that."
The work is important because many bacteria are becoming resistant to common antibiotics, which usually work by attacking the cell wall. If vulnerabilities can be found inside a cell, new types of antibiotics might be made. Although crescentin, the focus of Rupprecht's research, has been found in only one type of bacteria, some scientists believe this filament or a similar structure many be present in many other types of bacteria.
In her experiments, Rupprecht has been guided by Osigwe Esue, a doctoral student in the Johns Hopkins Department of Chemical and Biomolecular Engineering. Their findings are reported in a paper that has been submitted to a peer- reviewed science journal, with Rupprecht listed as a co- author.
Their research is supervised by Denis Wirtz, a professor in the department. Wirtz also sponsored Rupprecht in her application for a Provost's Undergraduate Research Award, which covered some of her laboratory costs and living expenses while she worked in the lab last summer.
She joined Wirtz's lab just over a year ago after hearing that it offered particularly challenging projects. Wirtz had begun studying the newly discovered crescentin, and Rupprecht gladly accepted the chance to assist. "I wanted to get involved because it's such a new protein," she said. "We need to know how it forms cytoskeletal structures. Then we can figure out how to dismantle it."
Rupprecht, who writes science articles for the collegiate magazine The Triple Helix in her spare time, said the hands-on lab experience has been invaluable. "Some of the stuff I've been doing looks easy in textbooks," she said. "But I've discovered that there's so much more that can go wrong in the lab."
Her professor said he doesn't hesitate to hand tough assignments to his younger students like Rupprecht. "This is the Wirtz lab signature," he said. "I throw very ambitious projects at my undergraduates. They're not here to wash dishes."
Wirtz said his undergraduates are usually up to the challenge, and many have gotten their names on scientific journal articles as a result of work done in his lab. Most of these young scientists, he said, have been supported by the university's undergraduate research grant program.
On March 16, Steven Knapp, university provost and senior vice president for academic affairs, will host the 13th annual Provost's Undergraduate Research Awards ceremony, which honors the 42 winners who conducted their projects in the summer and fall of 2005. Since 1993, about 40 students each year have received PURA grants of up to $3,000 to conduct original research; results of some projects have been published in professional journals. The awards, funded through a donation from the Hodson Trust, are an important part of the university's commitment to research opportunities for undergraduates.
The Johns Hopkins University is recognized as the country's first graduate research university, and is the leader among the nation's research universities in winning federal research and development grants. The opportunity to be involved in important research is one of the distinguishing characteristics of an undergraduate education at Johns Hopkins.
The Provost's Undergraduate Research Awards program provides one of these research opportunities, open to students in each of the university's four schools with full-time undergraduates: the Krieger School of Arts and Sciences, the Whiting School of Engineering, the Peabody Conservatory and the School of Nursing.
Color images of Rupprecht and Wirtz available; contact Phil Sneiderman.
Go to Headlines@HopkinsHome Page