Natural Pattern

Bundles of proteins, called microtubules, once lined up uniformly straight, begin to buckle and bend under compression stress generated their own growth. That distortion may be the beginning of pattern formation in natural objects.

Shaped like long, skinny straws, these proteins are puny - they measure only about 250 atoms wide - but play critical roles in the body. Microtubules help cells divide. They also act as scaffolds, giving cells their shape, and serve as train tracks of sorts, moving important bits like chromosomes and mitochondria around inside of cells.

As microtubules multiply, they form patterns that can be seen by the naked eye. The pattern is a series of waves that look a bit like zebra stripes. Chemical bonding and mechanical instability are responsible for the stripes.

At first, the microtubules line up uniformly, like pickets in a fence. As they continue to grow, they clump together in bundles of 200 to 300. Then these bundles buckle. The buckling is believed to occur because, as microtubules grow, they create energy and generate force. Then the bundles buckle to relieve compression stress.

--LiveScience Staff

• Amazing Images: Photos You Submit
• Image Galleries: Science All Around You
• Videos: Science and Nature in Action

Credit: Yongxing Guo and Yifeng Liu, Brown University