Featured Research

from universities, journals, and other organizations

How The Sea Urchin Grows New Spines

Date:
November 22, 2004
Source:
Weizmann Institute
Summary:
The sea urchin's tough, brittle spines are an engineering wonder. Composed of a single crystal from base to needle-sharp tip, they grow back within a few days after being broken off. Now, a team of scientists at the Weizmann Institute of Science has shown how they do it.

The broken tip of a sea urchin spine shows new growth. From base to tip, the spine is made up of a single crystal. The images were taken by Yael Politi with a scanning electron microscope as a part of the research, which was conducted together with Profs. Lia Addadi and Steve Weiner of the Structural Biology Department of the Weizmann Institute of Science.
Credit: Image courtesy of Weizmann Institute

The sea urchin's tough, brittle spines are an engineering wonder. Composed of a single crystal from base to needle-sharp tip, they grow back within a few days after being broken off. Now, a team of scientists at the Weizmann Institute of Science has shown how they do it.

While many crystals grow from component atoms or molecules that are dissolved in liquid, sugar and salt being the most familiar examples, the team of Profs. Lia Addadi and Steve Weiner, of the Institute's Structural Biology Department, found that the sea urchin uses another strategy. The material of the spines is first amassed in a non-crystalline form, termed "amorphous calcium carbonate" (ACC). Packets of ACC are shoveled out of the cells surrounding the base of the broken spine and up to the growing end. Within hours of arriving in place, the amorphous material, which is composed of densely packed, but disorganized molecules, turns to calcite crystal in which the molecules line up evenly in lattice formations.

Working with graduate student Yael Politi and Eugenia Klein and Talmon Arad of the Chemical Research Support Unit, Professors Addadi and Weiner used four different methods of investigation, including two kinds of electron microscopy, to look for the ACC as it was being deposited and turning to crystal. "The question," says Weiner "is why it should be so difficult to observe a process that seems to be so basic. Scientists have been studying it for over a hundred years. In fact, because the ACC is a transient phase, we had to develop new methods to catch it while it exists."

The captured images show microscopic needles that grow first straight out from the stump of the old spine, and then branch out to form a lacy structure that is hard but light. The crystalline structure of the old spine provides the template for the alignment of the molecules in the crystal, and thus controls the intricate, yet precise, growth pattern.

Though previous studies by the Weizmann group have shown the same strategy is used by immature sea urchins and mollusks in the larval stage to build internal skeletons, this is the first time that the process was observed in adult marine animals. It is far from obvious that larva and adult would use the same methods – their lifestyles are very different. For instance, the tiny sea urchin larva is transparent and swims around, while the round, spiky adult lives on the sea floor. This can translate into differences in biological processes, as well.

Because it works for both, Addadi and Weiner believe this method is probably a basic strategy used not only by close relatives of the sea urchin such as sea stars, but by a wide variety of spiny and shelled sea creatures like mollusks and corals. In addition, the idea of growing single crystals by first creating the material in an amorphous phase might prove useful to material scientists and engineers who want to produce and shape sophisticated synthetic materials that have the properties of single crystals.

Prof. Addadi's research is supported by the J & R Center for Scientific Research, the Ilse Katz Institute for Material Sciences and Magnetic Resonance Research, the Helen and Milton A. Kimmelman Center for Biomolecular Structure and Assembly, the Philip M. Kltuznick Fund for Research, the Minerva Stiftung Gesellschaft fuer die Forschung m.b.H., the Women's Health Research Center and the Ziegler Family Trust, Encino, CA. She holds the Dorothy and Patrick Gorman Professional Chair.

###

Prof. Weiner's research is supported by the Helen and Martin Kimmel Center for Archaelogical Science, the Philip M. Klutznick Fund for Research, the Alfred Krupp von Bohlen und Halbach Foundation, Women's Health Research Center, and George Schwartzman, Sarasota, FL. He is the incumbent of the Dr. Walter and Dr. Trude Borchardt Professional Chair in Structural Biology.

Images are available at http://wis-wander.weizmann.ac.il


Story Source:

The above story is based on materials provided by Weizmann Institute. Note: Materials may be edited for content and length.


Cite This Page:

Weizmann Institute. "How The Sea Urchin Grows New Spines." ScienceDaily. ScienceDaily, 22 November 2004. <www.sciencedaily.com/releases/2004/11/041119014820.htm>.
Weizmann Institute. (2004, November 22). How The Sea Urchin Grows New Spines. ScienceDaily. Retrieved July 25, 2014 from www.sciencedaily.com/releases/2004/11/041119014820.htm
Weizmann Institute. "How The Sea Urchin Grows New Spines." ScienceDaily. www.sciencedaily.com/releases/2004/11/041119014820.htm (accessed July 25, 2014).

Share This




More Plants & Animals News

Friday, July 25, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Boy Attacked by Shark in Florida

Boy Attacked by Shark in Florida

Reuters - US Online Video (July 24, 2014) An 8-year-old boy is bitten in the leg by a shark while vacationing at a Florida beach. Linda So reports. Video provided by Reuters
Powered by NewsLook.com
Goma Cheese Brings Whiff of New Hope to DRC

Goma Cheese Brings Whiff of New Hope to DRC

Reuters - Business Video Online (July 24, 2014) The eastern region of the Democratic Republic of Congo, mainly known for conflict and instability, is an unlikely place for the production of fine cheese. But a farm in the village of Masisi, in North Kivu is slowly transforming perceptions of the area. Known simply as Goma cheese, the Congolese version of Dutch gouda has gained popularity through out the region. Ciara Sutton reports. Video provided by Reuters
Powered by NewsLook.com
Dogs Appear To Become Jealous Of Owners' Attention

Dogs Appear To Become Jealous Of Owners' Attention

Newsy (July 23, 2014) A U.C. San Diego researcher says jealousy isn't just a human trait, and dogs aren't the best at sharing the attention of humans with other dogs. Video provided by Newsy
Powered by NewsLook.com
Professor Creates Site Revealing Where People's Cats Live

Professor Creates Site Revealing Where People's Cats Live

Newsy (July 23, 2014) ​It's called I Know Where Your Cat Lives, and you can keep hitting the "Random Cat" button to find more real cats all over the world. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

    Health News

      Environment News

        Technology News



          Save/Print:
          Share:

          Free Subscriptions


          Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

          Get Social & Mobile


          Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

          Have Feedback?


          Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
          Mobile: iPhone Android Web
          Follow: Facebook Twitter Google+
          Subscribe: RSS Feeds Email Newsletters
          Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins