Scientists in the US have simulated the transport of nutrients through maturing egg cells such as those found in newly formed embryos. Using a simple system comprising microtubules, motors and a fluid, they showed that tornado-like vortex flows allow critical components needed for egg cell development to mix and be transported rapidly around the cell. The work advances our understanding of how egg cells nourish themselves – a key process in organism growth and development.
Maturing egg cells, or oocytes, can be much bigger than other types of cells. This is because they must contain everything required to grow into entire organisms. Their large size has a major downside, though: it makes it harder for important nutrients to reach all parts of the cell.
For example, while it takes just 10 to 15 seconds for protein molecules to travel from one side of a typical human cell to the other via diffusion, in oocytes, the same process would take an entire day – far too long for the cell to be able to function properly. To compensate for their large size, oocytes have evolved special mechanisms to generate so-called “cytoplasmic streaming flows” that help nutrients and other molecules circulate more rapidly. However, the origin of these flows was not well understood.
In the new work, researchers led by computational biologist Michael Shelley found that they could create a self-organizing system in which materials flow around the model cell in ways that are strongly reminiscent .
