Biological complexity: beating cilia controls (Introduction)

by David Turell , Sunday, August 20, 2017, 18:29 (2434 days ago) @ David Turell

Liquids are moved in the body by hair-like cilia all beating in synchronized fashion like rowers in a boat:

https://www.sciencedaily.com/releases/2017/08/170818102316.htm

"Researchers have revealed that a molecule called Daple is essential for the correct orientation and coordinated beating of cilia on the surface of cells lining ventricles in the brain. Without Daple, the cilia develop a random arrangement and cannot produce a uniform flow of CSF. This in turn leads to a build-up of fluid, which is associated with swelling of the head, known as hydrocephalus.

"Some cells in the body contain long thin structures called cilia on their surface, which exhibit a whip-like motion that promotes the flow of fluid past the cell. Although these cilia are known to play vital roles in the body, much remains to be understood about their molecular components and the mechanisms by which they work. This is especially true for the cilia on cells that line the ventricles of the brain, which contain cerebrospinal fluid (CSF) that has various functions including cushioning the brain against potentially damaging impacts.

"A team at Nagoya University has shed light on this issue by revealing that a molecule called Daple is essential for cilia to adopt an arrangement by which they can beat in one direction at the same time, thereby creating a flow of fluid past the cell exterior. This arrangement on cell surfaces all along the lining of ventricles in the brain ensures the correct flow of CSF, which in turn prevents its accumulation associated with brain swelling known as hydrocephalus.

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"The findings also showed that the lack of Daple stopped cilia all adopting the same orientation on the same side of cells. Without the cilia all beating in the same direction, there would be no directional flow of CSF, leading to its accumulation and subsequent swelling.

"According to Masahide Takahashi, "Daple functions through a cytoplasmic structure called microtubules, which are protein filaments involved in various functions including maintaining the overall structure of cells. When Daple is absent, the microtubules are unable to accurately specify the arrangement of structures called basal bodies, from which the cilia develop."

"The team's findings should lead to a deeper understanding of diseases caused by the dysfunction of cilia. These include not only hydrocephalus, but also asthma and even female infertility, given the structural and functional similarities of cilia in the trachea and oviduct."

Comment: This is an irreducibly complex system that had to be designed from the beginning to be sure that liquid flowed in the proper direction. Has to work in the oviduct or the egg will not move to the uterus to be fertilized.