A common microbe that lives in water makes the strongest sticky material yet found in nature. The discovery might help scientists make extra-strong glue that holds tight even when wet.
Two microbe cells (bottom), with adhesive at the tips of their stalks, divide to produce daughter cells (at top), each with a long, thin tail.
Photo by Yves Brun/Indiana University
The bacterium is called Caulobacter crescentus. When it begins its life, it's a cell with a tail, called a flagellum, which it uses to move around. As the microbe gets older, its flagellum falls off, and a stalk grows in its place.
The end of the stalk produces a sticky substance made out of sugars and proteins. The bacterium uses this natural glue, called holdfast, to attach to rocks and other surfaces.
To measure holdfast's strength, scientists at Indiana University and Brown University grew C. crescentus on a piece of lab equipment, called a micropipette, which is thin and bendable. Then, they pulled the microbe's body away from the material. The researchers estimated holdfast's strength by measuring how much the micropipette bent before the microbe let go.
You may have read about the hairs on gecko feet, which allow these lizard-like animals to walk on ceilings (see "How a Gecko Defies Gravity"). One gecko hair has a holding power of about 10 newtons per square millimeter. A newton is a unit of force.
In comparison, holdfast's strength measured 68 newtons per square millimeter, the scientists report. A 10-centimeter-by-10-centimeter wet surface covered with holdfast could hold as much as 70 tons (140,000 pounds).
When ordinary tape and glue aren't strong enough, maybe nature will provide a new source of sticking power.E. Sohn
Cunningham, Aimee. 2006. Microbe holds fast. Science News 169(April 29):269-270. Available at http://www.sciencenews.org/articles/20060429/note13.asp .
You can learn more about microbe glue at newsinfo.iu.edu/news/page/normal/3258.html (Indiana University).
McDonagh, Sorcha. 2004. Gooey secrets of mussel power. Science News for Kids (Jan. 21). Available at http://www.sciencenewsforkids.org/articles/20040121/Note2.asp .
______. 2003. Sticking around with gecko tape. Science News for Kids (June 11). Available at http://www.sciencenewsforkids.org/articles/20030611/Note2.asp .
Sohn, Emily. 2005. Gecko's sticky feet clean themselves. Science News for Kids (Jan. 12). Available at http://www.sciencenewsforkids.org/articles/20050112/Note3.asp .
______. 2004. Inspired by nature. Science News for Kids (Nov. 3). Available at http://www.sciencenewsforkids.org/articles/20041103/Feature1.asp .
______. 2003. How a gecko defies gravity. Science News for Kids (Nov. 19). Available at http://www.sciencenewsforkids.org/articles/20031119/Feature1.asp .