Video of Volvox embryo turning itself inside out

Researchers has managed to film a 3D video of a they call as the “most important time in your life”. The live embryo was clearly seen shape-shifting from a sphere to a mushroom and back to a sphere again. The behavior or the organism will help the team understand an important mechanical process in the development of early animals.

Researchers captured the first 3D images of a green alga known as Volvox, which provided them an ideal test case for their study. The team used fluorescence microscopy to observe the embryos in its live state. From there, they make and test morphogenesis from a mathematical model.

Morphogenesis is a natural biological process that occurs during the development of an organism giving it shape and structure. And it is the main process that researchers from the University of Cambridge are trying to study especially in the case of the algal embryo that shifts from a sphere to a mushroom and goes back to a sphere again.

The Volvox embryo resembles the process of gastrulation among animal embryos, which was initially reported by biologist Lewis Wolpert. In gastrulation process, animal embryos fold itself inward to form a cup-like shape which gives rise to germ layers from where all bodily organs are formed. It is also the complex process that involves cell shape changes, cell division and migration.

Volvox embryos display similar development only that it has some weird additional movement – the embryos turn “right-side out” as the process is occurring. It was able to shape-shift its cells by altering the connection in between cells, which makes it the ideal model for studying cell sheet folding. The amazing process in volvox embryos occurs in roughly an hour.

Professor Raymond E. Goldstein, led researcher from the Department of Applied Mathematics and Theoretical Physics, said that, “Until now there was no quantitative mechanical understanding of whether those changes were sufficient to account for the observed embryo shapes, and existing studies by conventional microscopy were limited to two-dimensional sections and analyses of chemically fixed embryos, rendering comparisons with theory on the dynamics difficult.”

Volvox
Volvox

The 3D video that the team was able to film explains how cell shape changes affect the process of inversion among embryos. During inversion, one side of the embryo decreases in size as the other side elongates to grow bigger. This allowed the team to make the first successful mathematical model that explains the process.

During an interview, Dr. Stephanie Höhn, who is at the helm of the study, reported that, “It’s exciting to be able to finally visualize this intriguing process in 3D. This simple organism may provide ground-breaking information to help us understand similar processes in many different types of animals.”

The conclusion explains that cell shape changes in an invagination region are caused by active intrinsic force acting inside the cell, and not due to some sort of deformations. The model that the team created may provide accurate analysis for other higher animals since similar behavior was observed on both organisms.

Dr. Aurelia Honerkamp-Smith, co-author of the study, assured scientists that, “The power of this mathematical model is that we can identify which cell deformations are needed to cause the embryo movements that we observe in nature.” Furthermore, the model will be used to answer other mysterious process happening during morphogenesis.

The study published in the journal Physical Review Letters suggests that the mathematical problem will help solve topological problems, including the process of neurulation leading to the formation of the tissue that makes up the spinal cord.

 

View original article at: Live Algal Embryo Caught Shape-Shifting on 3D video 

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