Nav: Home

Making spines from sea water

December 05, 2016

Some sea creatures cover themselves with hard shells and spines, while vertebrates build skeletons out of the same minerals. How do these animals get the calcium they need to build these strong mineral structures? Professors Lia Addadi and Steve Weiner of the Weizmann Institute of Science's Structural Biology Department asked this question about sea urchins, which need to extract quite a few calcium ions from sea water to build their spines. The answer surprised them, and it could change the way scientists think about the process of biomineralization.

Several years ago, Addadi and Weiner had discovered that sea urchins build their spines with tiny packets of "unorganized" material that hardens into crystal when laid in place. "So the question went back a step: How do they get the calcium ions they need to make this material in the first place?" says Addadi. "Free calcium is not abundant in sea water," adds Weiner, "so they need an efficient way to extract and concentrate the ions."

To answer the question the researchers, including Netta Vidavsky, needed methods to observe the animal's cells "as is," that is, as they are in life, water included. For this the group turned to Dr. Andreas Schertel of Carl Zeiss Microscopy in Germany and Dr. Sefi Addadi of the Weizmann Institute of Science's Life Sciences Core Facilities. Very new cutting-edge techniques enabled them to observe thin slices of the cells in sea urchin embryos and then to reconstruct three-dimensional images of these cells and their intake of labeled calcium ions. "Even a few years ago, we could not have done this study," says Addadi.

The images showed that sea urchin larval cells actually "drink" seawater, taking in drops of water and manipulating the ions in the water within the confines of the cell. This is in contrast to the theory that these cells take in only ions, one at a time, through special channels in their outer membranes. The cells they observed were filled with networks of bubbles called vacuoles that collect the calcium ions, evidently creating concentrated packages of calcium for building the spines.

This method may be more energy efficient than taking in ions through channels (which the cells also did), but it presents another problem: The cells must be able to pick out the calcium as well as expel other ions in the sea water, especially the sodium and chloride. "Researchers may be busy for years to come figuring out how these cells manipulate the ions in the sea water they drink," says Weiner.

Addadi and Weiner point out that this is not the first time this type of calcium ion intake has been observed. Prof. Jonathan Erez of the Hebrew University of Jerusalem had described this phenomenon in single-celled, hard-shelled microorganisms called foraminifera a decade ago. At the time, it was thought to be a "curiosity," but finding the same process in two very different creatures suggests that it may be quite widespread. Although we do not live in sea water, even the cells that build our bones may use a similar method to obtain calcium.
-end-
Prof. Lia Addadi's research is supported by the Jeanne and Joseph Nissim Foundation for Life Sciences Research. Prof. Lia Addadi is the incumbent of the Dorothy and Patrick Gorman Professorial Chair.

Prof. Stephen Weiner's research is supported by the Helen and Martin Kimmel Center for Archaeological Science, which he heads; the Dangoor Accelerator Mass Spectrometer Laboratory; and the estate of George and Beatrice F. Schwartzman. Prof. Weiner is the incumbent of the Dr. Walter and Dr. Trude Borchardt Professorial Chair in Structural Biology.

The Weizmann Institute of Science in Rehovot, Israel, is one of the world's top-ranking multidisciplinary research institutions. Noted for its wide-ranging exploration of the natural and exact sciences, the Institute is home to scientists, students, technicians and supporting staff. Institute research efforts include the search for new ways of fighting disease and hunger, examining leading questions in mathematics and computer science, probing the physics of matter and the universe, creating novel materials and developing new strategies for protecting the environment.

Weizmann Institute of Science

Related Calcium Articles:

'Give me the calcium!' Tulane virus takes over cellular calcium signaling to replicate
Researchers uncover the first piece of functional evidence suggesting that Tulane virus and human norovirus use viroporins to control cellular calcium signaling.
Carbon dots make calcium easier to track
Prof. DONG Wenfei's research group from the Suzhou Institute of Biomedical Engineering and Technology (SIBET) has developed a new type of fluorescent carbon dot that can effectively detect calcium levels in cells.
Calcium batteries: New electrolytes, enhanced properties
Calcium-based batteries promise to reach a high energy density at low manufacturing costs.
Chelated calcium benefits poinsettias
Cutting quality has an impact on postharvest durability during shipping and propagation of poinsettias.
New study uncovers the interaction of calcium channels
Korean researchers have identified the interactions of the combinants among calcium channel proteins that exist in nerve and heart cells.
Calcium-catalyzed reactions of element-H bonds
Calcium-catalyzed reactions of element-H bonds provide precise and efficient tools for hydrofunctionalization.
Memory molecule limits plasticity by calibrating calcium
Researchers at the Max Planck Florida Institute for Neuroscience in collaboration with researchers at Emory University and the National Institute of Environmental Health Sciences, have for the first time identified a novel role for the CA2-enriched protein RGS14 and provided insights into the mechanism by which it limits plasticity.
A bioengineered tattoo monitors blood calcium levels
Scientists have created a biomedical tattoo that becomes visible on the skin of mice in response to elevated levels of calcium in the blood.
The dinosaur menu, as revealed by calcium
By studying calcium in fossil remains in deposits in Morocco and Niger, researchers have been able to reconstruct the food chains of the past, thus explaining how so many predators could coexist in the dinosaurs' time.
Communication via calcium wave
The hormone auxin is a key regulator of plant growth and development.
More Calcium News and Calcium Current Events

Trending Science News

Current Coronavirus (COVID-19) News

Top Science Podcasts

We have hand picked the top science podcasts of 2020.
Now Playing: TED Radio Hour

Listen Again: Reinvention
Change is hard, but it's also an opportunity to discover and reimagine what you thought you knew. From our economy, to music, to even ourselves–this hour TED speakers explore the power of reinvention. Guests include OK Go lead singer Damian Kulash Jr., former college gymnastics coach Valorie Kondos Field, Stockton Mayor Michael Tubbs, and entrepreneur Nick Hanauer.
Now Playing: Science for the People

#562 Superbug to Bedside
By now we're all good and scared about antibiotic resistance, one of the many things coming to get us all. But there's good news, sort of. News antibiotics are coming out! How do they get tested? What does that kind of a trial look like and how does it happen? Host Bethany Brookeshire talks with Matt McCarthy, author of "Superbugs: The Race to Stop an Epidemic", about the ins and outs of testing a new antibiotic in the hospital.
Now Playing: Radiolab

Dispatch 6: Strange Times
Covid has disrupted the most basic routines of our days and nights. But in the middle of a conversation about how to fight the virus, we find a place impervious to the stalled plans and frenetic demands of the outside world. It's a very different kind of front line, where urgent work means moving slow, and time is marked out in tiny pre-planned steps. Then, on a walk through the woods, we consider how the tempo of our lives affects our minds and discover how the beats of biology shape our bodies. This episode was produced with help from Molly Webster and Tracie Hunte. Support Radiolab today at Radiolab.org/donate.