Cilia — short, hair-like fibers — are widely present in nature. Single-celled paramecia use one set of cilia for locomotion and another set to sweep nutrients into their oral grooves. Researchers at Brown, including Physics graduate student Il-yong Jung, have discovered that those two cilia sets operate at different speeds when the viscosity of the environment changes. That suggests different molecular motors driving them, which could help explain how cilia have come to be used for so many different tasks in nature.
The study looked at the cilia of the single-celled, water-dwelling paramecium. Paramecia are covered with cilia that beat like thousands of tiny oars, propelling the creatures through the water. At the same time, cilia around the paramecium’s “oral groove” sweep nutrients inward, providing all-important nourishment. Through a series of experiments, the researchers showed that oral groove cilia appear to have different molecular motors than the rest of a paramecium’s cilia.
This is the first time anyone has shown two motor behaviors by cilia in a single cell, says James Valles, chair of the Department of Physics at Brown and one of the paper’s senior authors. With a bit more study, Valles hopes this finding could shed light on the molecular mechanisms responsible for these two motor behaviors.
Read more of Kevin Stacey's article about cilia.