In a stunning feat of microscopy, scientists have been able to create a video showing a tiny virus circulating around cells before infection.
“What we’re finding is that the virus will have many transient contacts, very short contacts over time, with many cells before it binds to any particular cell,” said Kevin Welsher, associate professor of chemistry at Duke University , in an interview with Quirks & Quarks host Bob McDonald.
The improvement over previous techniques for capturing this kind of activity is like the difference between a modern Hollywood movie and a stuttering flip book.
Welsher said he and his colleagues spent seven years developing the technique and published their findings in the journal Nature Methods.
Their breakthrough came when they figured out how to track the virus as it moved between the three-dimensional layers of epithelial cells. It is the cells that line the surfaces of the body, such as in the nose, lungs and intestines, that are the first to come into contact with the viruses.
Scientists are aiming to capture the entire infection process to learn more about how a virus, like the COVID-19 coronavirus, can cross the mucosal layer and enter cells, such as those in the lungs, where it can potentially wreak havoc. as seen in the left X-ray image. (Ronnie Hartman/AFP/Getty Images)
Scientists are eager to gather more details about how the viruses hijack these cells, so this new 3D microscopy could improve their ability to watch the process unfold.
Welsher describes the motion of the virus as a “random walk” in which heat energy manifests itself as small, random movements in all three dimensions. This, over time, propels the small virus particles around the extracellular environment.
“Prior to what we were doing here, the usual way to look at a three-dimensional system was to take images of each slice of the system and build it into a total volume,” Welsher explained.
But the time it takes the camera, with its fixed field of view, to move to different angles to capture the next frame of the moving target means they miss details about the fast-moving virus they’re trying to capture.
That’s valuable imaging information that doesn’t get recorded, which Welsher said their new technique reveals.
They do this by locking the camera’s field of view on the viral target, much like a helicopter in a high-speed car chase.
The research team’s video captures only part of the infection process, where the virus binds to the cell. Welsher said the researchers’ ultimate goal is to capture the entire infection process, as the virus first makes its way through the mucus layer that covers epithelial cells and eventually enters a cell to replicate.
WATCH | Real-time footage of viruses before they attack a cell:
Produced and written by Sonya Buyting.
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