Current light-sheet microscopy techniques involve illuminating one side of the sample. Either one side of a developing organism is imaged continuously, or two sides are viewed alternately, with the resultant data reconstructed to form a three-dimensional view. However, viewing from one side at a time means that the cells cannot be tracked as they migrate from top to bottom, and rotating the sample to view both sides takes so much time that when the next image is taken the cells have changed, so that they no longer line up.
Simultaneous multi-view imaging solves this problem by taking images from opposing directions at the same time and piecing data together in real time. This required massive computing power; the data sets were as large as 11 terabytes (the amount of data on about 2500 DVDs) in one of the studies1. Now every cell in a D. melanogaster embryo can be visualized as the animal develops from a fertilized egg into hatching larva. . .
Keller says that the techniques allow researchers to see what is happening in an entire animal through every stage of development, and what goes wrong as a result of different mutations. “Until now, developmental biology was a qualitative field, describing different mutations and their effect during development. But we couldn’t see what individual cells were doing in an individual embryo,” he says. Keller and his colleagues are now using the technique to follow the growth and differentiation of neurons in the developing brain of D.melanogaster and other species.
Below is the development of a Drosophila melanogaster embryo within the egg. You can see the classic insect segmentation form as the cells move about. After about a day, this egg will hatch into a larva (the “maggot”), which after about five more days will crawl out of its food (they’re reared in vials of agar-based medium), pupate on the wall of the vial, and then begin the transformation into an adult fly. At 25 degrees C (about 78F), it takes about 8-10 days from when a fly lays an egg until that egg becomes an adult fly (and another 12 hours or so before the adult female can lay another egg), so one can go through 30 or more generations per year. That’s why flies are so good for genetic and evolutionary work.
Tomer, R., Khairy, K., Amat, F. & Keller, P. Nature Methods http://dx.doi.org/10.1038/nmeth.2062 (2012).
Krzic, U., Gunthur, S., Saunders, T. E., Streichan, S. J. & Hufnagel, L. Nature Methods http://dx.doi.org/10.1038/nmeth.2064 (2012).