Fruit flies may be relatively simple organisms, but a new time-lapsed video at the cellular level showing their growth into the larval stage is incredibly active and complex.
More than 1 million photographs taken with a new technique were used to document from two-and-a-half hours into development through 20 hours old. According to Wired, researchers used a new microscope called Multi-View SPIM,which builds on simultaneous multiview light-sheet microscopy, which "illuminates a biological sample with thin sheets of light positioned at the focal planes of multiple high-resolution digital cameras." Images of "unprecedented detail" are derived from the equipment taking 175 million voxels of information, which Wired explains are the 3-D version of pixels, per second.
The researchers using this technique cite it as beneficial for viewing live biological samples, as it can capture the whole organism at one time.
io9 has more on how this works:
To capture this video, the new microscope shines a thin sheet of light on the embryo, illuminating one layer of the sample at a time, to obtain an image of the whole sample with minimal light-induced damage. MuVi-SPIM builds upon the Selective-Plane Illumination Microscopy (SPIM) technology developed at EMBL a few years ago. But unlike SPIM, the new microscope takes four full images from different angles, eliminating the need to rotate the sample. This results in faster imaging and the ability to merge the four images into a single high-quality three-dimensional image - something that's never been done before.
"The practical approach in biological live imaging has been to reduce the observation of large systems to small functional subunits and to study these one at a time,” Wired reports a team led by Howard Hughes Medical Institute cell biologist Philipp Keller writing in Nature Methods.
“This video shows a fruit fly embryo from when it was about two-and-a-half hours old until it walked away from the microscope as a larva, 20 hours later,” Lars Hufnagel, from the European Molecular Biology Laboratory (EMBL) in Heidelberg, Germany, said in a statement. “It shows all the hallmarks of fruit fly embryonic development in three dimensions.”
Watch the time-lapse of the fly's development into a larvae:
Live Science describes what you see in the video as starting off with "what looks like a bloblike organism covered with tiny projections." These "projections" are cells. As time progresses the cells reorient and differentiate as the fly embryo enters other stages of development.
The cells' nuclei were tagged in a way that would allow them to glow under fluorescent light, making the development easier to view.