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Computer
visualization and x-ray microscopy combine to picture the interior
of living cells. |
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From Stone Age drawings on the walls of caves to Silicon Age micrographs
of atoms aligned in a crystal, humans have created images of that which
interests them so others can learn. What most interests Carolyn Larabell,
a cell biologist and microscopist with Berkeley Lab's Life Sciences Division,
are the proteins inside living cells and the things that they do. To image
these proteins and their activities, Larabell has mastered both electron
and confocal microscopy and is now blazing new trails with the x-ray microscope,
XM-1, at Berkeley Lab's Advanced Light Source (ALS).
"We've been one of the first to do live-cell imaging," says
Larabell of herself and her group, meaning that the cells are alive and
intact when imaged rather than fixed in a solution or sliced into thin
sections as required by other microscopy technologies. "This approach
tells both a spatial and temporal story, which is important because proteins
are dynamic rather than static."
Born and raised on a farm outside a small town in upper Michigan, Larabell
came to be a pioneer in the fledgling field of x-ray microscopy somewhat
circuitously, by way of a Ph.D. in zoology from Arizona State University.
It was while doing postdoctoral research at UC Davis on developmental
biology, that she got involved in electron microscopy in order to image
calcium. In 1994 she came to Berkeley Lab to set up an intermediate voltage
transmission electron microscope. She soon began working with visible
light wavelengths used in a confocal microscope. The dual experience served
her well for working with x-rays.
"Microscopists who work with visible light tend to use fast but
harsh cell preparation techniques, because at that resolution they won't
see their mistakes," she says. "With electron microscopy, every
flaw is literally magnified so the preparation techniques are incredibly
arduous. Having worked with both, I'm willing to change my protocols to
find the best and most efficient."
Larabell's flexible approach has reaped major dividends for the field
of cell biology. Her confocal images have graced the covers of numerous
scientific publications and her x-ray images are now poised to do likewise.
Working with the late x-ray microscope pioneer, Werner Myer-Illse, and
others, she has developed a technique for using x-ray microscopy to obtain
unprecedented images of labeled proteins inside of whole cells in a hydrated
state. Images, produced at XM-1, already show four times better resolution
than images from the best visible light microscopes.
"Our ultimate goal is to combine the spatial resolution
power of x-ray microscopy with the temporal information you can get from
visible light microscopy," Larabell says. "It's a lot of work
but I think we're making pretty good progress."
More
about Carolyn Larabell

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