WASHINGTON : US researchers have captured the first X-ray portraits of living bacteria.
The advance is the first step toward possible X-ray explorations of the molecular machinery at work in viral infections, cell division, photosynthesis and other processes that are important to biology, human health and our environment, researchers said.
The research took place at SLAC National Accelerator Laboratory’s Linac Coherent Light Source (LCLS) X-ray laser, a US Department of Energy (DOE) Office of Science User Facility.
“We have developed a unique way to rapidly explore, sort and analyse samples, with the possibility of reaching higher resolutions than other study methods,” said Janos Hajdu, a professor of biophysics at Uppsala University in Sweden, which led the research.
“This could eventually be a complete game-changer,” Hajdu said.
The experiment focused on cyanobacteria, or blue-green algae, an abundant form of bacteria that transformed Earth’s atmosphere 2.5 billion years ago by releasing breathable oxygen, making possible new forms of life that are dominant today.
Cyanobacteria play a key role in the planet’s oxygen, carbon and nitrogen cycles.
Researchers sprayed living cyanobacteria in a thin stream of humid gas through a gun-like device. The cyanobacteria were alive and intact when they flew into the ultrabright, rapid-fire LCLS X-ray pulses, producing diffraction patterns recorded by detectors.
The diffraction patterns preserved details of the living cyanobacteria that were compiled to reconstruct 2-D images. Researchers said it should be possible to produce 3-D images of some samples using the same technique.
The technique works with live bacteria and requires no special treatment of the samples before imaging.
Other high-resolution imaging methods may require special dyes to increase the contrast in images, or work only on dead or frozen samples.
The technique can capture about 100 images per second, amassing many millions of high-resolution X-ray images in a single day.
This speed allows sorting and analysis of the inner structure and activity of biological particles on a massive scale, which could be arranged to show the chronological steps of a range of cellular activities.
“You can study the full cycle of cellular processes, with each X-ray pulse providing a snapshot of the process you want to study,” said Tomas Ekeberg, a biophysicist at Uppsala University.
While optical microscopes and X-ray tomography can also produce high-resolution 3-D images of living cells, LCLS, researchers said, could eventually achieve much better resolution – down to fractions of a nanometre, or billionths of a metre, where molecules and perhaps even atoms can be resolved.
The research is published in the journal Nature Communications. (AGENCIES)
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