WSU biologist helps find new way to study bacteria
3:40:31 PM CDT - Thursday, November 04, 2004
By Amy Geiszler-Jones
A WSU biologist, working with a team of researchers from Notre Dame University and the Argonne National Laboratory, has found a new way to study individual living bacteria cells and analyze their chemistry.
The group's research was published in the Oct. 22 issue of Science, a weekly journal that is to scientists what the New England Journal of Medicine is to the medical field.
Mark Schneegurt, an assistant professor in WSU's biological sciences department, and his colleagues began delving into a way to study bacteria and how metal binds to the tiny organisms nearly eight years ago, shortly after Argonne, a U.S. Department of Energy lab run by the University of Chicago, built a super-powerful synchrotron X-ray research facility.
With a Star Trek-like sounding name and capabilities, the Advanced Photon Source is a huge circular research facility that is basically a particle accelerator that emits X-ray beams at high energy. Only two such high-tech, mega-million-dollar facilities exist in the world.
"It's extraordinarily powerful," Schneegurt explained, "like wrapping-your-arms-around-two-nuclear-explosions powerful. There's a lot of energy, but no heat, in those X-ray beams." The radiation generated in the facility has been known to set off Geiger counters in the parking lot, Schneegurt said.
The physicists at Argonne devised a way to produce X-ray beams small enough to probe single bacteria cells, which are typically one-hundredth the diameter of a human hair. And in another pioneering research feat, the bacteria lived to tell their story, so to speak.
"No other technique has been capable of determining the metabolic state of a single hydrated cell and the chemical speciation of metals on, in or near a bacterial cell," said Ken Kemner, an Argonne researcher who was the lead author of the Science article.
Schneegurt provided the bacteria — the single-cell Pseudomonas fluorescens — grown on a special type of plastic. The spots of bacteria were so tiny, Schneegurt had to put the biofilm under a microscope to map their locations. Free-floating, or planktonic, bacteria samples were also used in the experiments. The metal in the experiments was chromium.
The samples were sent to Argonne, where researchers blasted the bacteria with the X-rays and photographed the results. Schneegurt helped analyze the collected data.
While other researchers have used smaller X-ray beams on frozen bacteria, this group's research is significant in that live samples were used, and the researchers believe the cells survived.
"They might have had their DNA shredded by the strong X-rays, but they weren't fried since there was no heat," Schneegurt said. "We learned lots of complicated stuff about the way metal binds."
Figuring out how metal binds to bacteria can have implications in studying how toxic metals, such as lead, arsenic, chromium and zinc, move through the environment. For example, metals often hitch a ride on bacteria in groundwater to move around.
Since the group's work involves using technology that sounds as if it came from a futuristic space script, it's no surprise that another of its applications could be in detecting life from samples gathered in the universe. Scientists usually look for evidence of fossilized bacteria to determine if life existed elsewhere in the solar system.
But since bacteria exist in such tiny microscopic form, finding such evidence will be difficult.
This group's new technique might well help make that detection easier, said Schneegurt, who's clearly excited about possibly playing a role in that.
"When I get together with these guys, we like to sit around, drink beer and talk about how we'll discover life on Mars," he said.