Upside down and inside out

Researchers have captured the first 3D video of a living algal embryo turning itself inside out, from a sphere to a mushroom shape and back again. The results could help unravel the mechanical processes at work during a similar process in animals, which has been called the "most important time in your life." This simple organism may provide ground-breaking information to help us understand similar processes in many different types of animals - Stephanie Höhn Researchers from the University of Cambridge have captured the first three-dimensional images of a live embryo turning itself inside out. The images, of embryos of a green alga called Volvox, make an ideal test case to understand how a remarkably similar process works in early animal development. Using fluorescence microscopy to observe the Volvox embryos, the researchers were able to test a mathematical model of morphogenesis - the origin and development of an organism's structure and form - and understand how the shape of cells drives the process of inversion, when the embryo turns itself from a sphere to a mushroom shape and back again. Their findings are published today (27 April) in the journal Physical Review Letters . The processes observed in the Volvox embryo are similar to the process of gastrulation in animal embryos - which biologist Lewis Wolpert called "the most important event in your life." During gastrulation, the embryo folds inwards into a cup-like shape, forming the primary germ layers which give rise to all the organs in the body.