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High-Speed Microscopic Engine Found

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  • Chris Ashcraft
    http://livescience.com/animalworld/051212_nano_spring.html High-Speed Microscopic Engine Found By Ker Than In 1702, the famous Dutch scientist Anton van
    Message 1 of 1 , Dec 14, 2005
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      http://livescience.com/animalworld/051212_nano_spring.html

      High-Speed Microscopic Engine Found
      By Ker Than

      In 1702, the famous Dutch scientist Anton van Leeuwenhoek made an interesting discovery while
      gazing at some pond water through a hand-made microscope: He observed a bell-shaped organism that
      used a long, rapidly contracting stalk to attach itself to objects in its environment.

      More than 300 years after Leeuwenhoek first observed Vorticella convallaria, as the microscopic
      pond organism is now called, scientists are finding that its spring-like stalk is one of the
      fastest cellular engines ever discovered.

      Danielle Cook France, a biological engineer at the Massachusetts Institute of Technology, believes
      the stalk could be incorporated into future generations of nano-sized cellular engines.

      Nanomaterials typically involve a measurement of at least one dimension that is 100 nanometers or
      less. A human hair is roughly 100,000 nanometers wide.

      The spring in the stalk is made up of contractile protein fibers and is called a "spasmoneme." At
      rest, the stalk is elongated like a stretched telephone cord, but when contracted, it winds back
      in a flash to form a tight coil.

      Using high-speed microscopes and special chemicals that could freeze the stalk in mid-coil, France
      and colleagues were able to take snap-shots of the stalk as it contracted.

      The researchers estimated that Vorticella's spasmoneme could contract at a speed of about 8
      centimeters per second. That's the equivalent of you walking the length of more than three
      football fields in one second.

      Researchers think a cellular protein known as spasmin is responsible for Vorticella's remarkable
      speed. Spasmin belong to a family of proteins called centrins; in humans and other organisms,
      centrins play an important role in cell division.

      "If it's knocked out in yeast, for example, the cells don't divide at all," France said.

      Unlike many other cellular proteins, centrins aren't powered by ATP, a high-energy molecule that
      drives many biochemical reactions; instead, they run on calcium.

      France said that from an engineering perspective, using calcium to power a mechano-chemical engine
      is ideal because it's a fuel that can't be burned up. ATP can only be used once and then must be
      recycled by the cell.

      Calcium, in contrast, doesn't need to be recycled and provides power through changes in
      concentration. So the only limitation to its use as an energy source is the speed at which the
      cell can pump calcium between different compartments.

      France said her team is currently working on making fibers out of spasmin-type proteins but she
      thinks the nano-springs could find other applications as well.

      "Anywhere that you would need movement to be created in a small device, that's where you would use
      these," France said.

      France presented her findings Sunday at the 45th Annual Meeting of the American Society for Cell
      Biology in San Francisco.



      Christopher W. Ashcraft
      Northwest Creation Network
      http://nwcreation.net
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