Robert Macnab
Bacteria Doing the Locomotion
(This interview is from March 2003)
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PERSON-TO-PERSON |
Robert Macnab, Ph.D.,
professor of molecular biophysics and biochemistry at Yale
University, passed away September 7, 2004. He was 63.
An expert on the bioenergetics of motility, Macnab joined the faculty at Yale in 1973 and served as chair of his department from 1992 until 1995.
Macnab is survived by his wife and colleague May
Kihara
Macnab, an accomplished scientist in Yale's
Department of Molecular Biophysics and Biochemistry. |
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Scotsman Robert Macnab thinks a lot
about swimming. But his vision isn’t focused on some
sandy tropical beach, but deep inside the microscopic world
of bacteria, whose fin-like
organelles
called
flagella
enable them to swim inside cells, across a drop of water,
and through other watery worlds unseen by the naked eye.
 |
| Robert
Macnab is incredulous that he could spend his
life studying swimming bacteria. |
Macnab has devoted much of his research career to learning how
flagella are built and how they work to propel the bacteria around their
environment.
Originally, Macnab had set out on a career as a petroleum chemist. His
first job after college was with oil industry giant British Petroleum.
Embarking on what was supposed to be a brief leave to obtain a Ph.D.,
he landed in a lab focused on chemical biodynamics that gave him his first
taste of research in biology. He was captivated. “I didn’t know
anything about this,” he says. “But I wanted to learn more and
be more involved in it.”
Instead of returning to Scotland or to BP, Macnab sought a postdoctoral
position to pursue his newfound interest. But, he notes, “Because
I had no formal training in biology, I wasn’t a particularly marketable
product.” Luckily, Daniel Koshland at the University of California,
Berkeley, was then making forays into bacterial chemotaxis, the process
by which bacteria sense and move toward attractive chemicals or away from
repellant ones.
Koshland was seeking a successor to a departing postdoctoral associate
who had been working on the subject and also happened to be a chemist
by training. “[Koshland’s] interest in the field [of
chemotaxis
and motility] got me interested,” Macnab says. “In other words,
I didn't select the field, I selected the opportunity.”
But from the moment he first saw flagella under the microscope, Macnab
was hooked on studying them. While examining flagellated bacteria under
an intense light beam one day, Macnab says, “I suddenly realized
I was seeing the flagella. I could actually see them functioning.”
His research on chemotaxis in Koshland's lab helped to demonstrate that
bacteria have a primitive memory.
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| Bacterium with flagellar assembly courtesy of MicrobeLibrary.
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After moving to Yale University in 1973, Macnab began to analyze what
the external parts of a flagellum do to propel a bacterial
cell. Interested in analyzing each of the components
of the organelle, he and his collaborators spent much
of the next 27 years painstakingly piecing together an
ever-more-comprehensive picture of the structural make-up
of flagella.
“We were just chipping away,” he says. “Every
step seemed like just a little step. But then you look
back and realize it's quite a body of information.”
Someday, the knowledge Macnab and colleagues have acquired
about how primitive bacteria learn where to go or avoid
going may have practical applications in medicine.
