New microscope offers clear images of entire organisms

Researchers have developed a new high-speed microscope that can give scientists a clearer, more comprehensive view of biological processes as they unfold in living animals.

The microscope produces images of entire organisms, such as a zebrafish or fruit fly embryo, with enough resolution in all three dimensions that each cell appears as a distinct structure.

What is more, it does so at speeds fast enough to watch cells move as a developing embryo takes shape and to monitor brain activity as it flashes through neuronal circuits.

The device called the IsoView light sheet microscope was developed at Howard Hughes Medical Institute's Janelia Research Campus in Virginia, US.

"Right now it is our most advanced microscope for imaging, and we are certainly going to take advantage of it," said one of the researchers Philipp Keller.

Keller and his colleagues used the IsoView to visualise cell-by-cell activity throughout the nervous system of an entire living fruit fly larvae, an organism that has more than 10,000 neurons.

Because the IsoView can produce images as the larvae moves freely in a loose gel, Keller said, "this opens up the possibility of functional imaging in an entire, behaving animal. It is even possible to perform high-speed functional imaging over developmental time scales, as we demonstrated in imaging a fruit fly embryo developing into a larva."

The scientists also performed high-resolution functional imaging of activity in the entire brain of a larval zebrafish, demonstrating that neurons in the deepest, least accessible regions of the brain could be seen clearly, separate from their neighbours.

The findings were detailed online in the journal Nature Methods.