Featured Research

from universities, journals, and other organizations

A crowning success for crayfish

Date:
May 18, 2012
Source:
Max Planck Institute of Colloids and Interfaces
Summary:
Australian freshwater crayfish have a tooth enamel very similar to humans. Nature sometimes copies its own particularly successful developments. Scientists have now found that the teeth of the Australian freshwater crayfish Cherax quadricarinatus are covered with an enamel amazingly similar to that of vertebrates. Both materials consist of calcium phosphate and are also very alike in terms of their microstructure. This extremely hard substance has apparently developed in freshwater crayfish independently from vertebrates, as it makes the teeth particularly strong.

X-ray micro-computer-tomography of the mandibular apparatus of a freshwater crayfish. The enamel, mainly consisting of calcium phosphate crystals, appears bright.
Credit: Shmuel Bentov / Ben-Gurion University

Nature sometimes copies its own particularly successful developments. A team of scientists from the Max Planck Institute of Colloids and Interfaces in Potsdam and the Ben-Gurion University at Beer-Sheva in Israel has now found that the teeth of the Australian freshwater crayfish Cherax quadricarinatus are covered with an enamel amazingly similar to that of vertebrates. Both materials consist of calcium phosphate and are also very alike in terms of their microstructure. This extremely hard substance has apparently developed in freshwater crayfish independently from vertebrates, as it makes the teeth particularly strong.

In terms of hardness, enamel sets a unique standard, which is hardly met by any other other biological material. The hardness and strength of the outer layer of the crown of the tooth in humans and other vertebrates are due to tiny crystals of calcium phosphate, which also strengthen bones. And because the composition and structure of the enamel have made it exceptionally strong, the evolution in freshwater crayfish, too, has produced a highly mineralised protective layer for the mandibles that is very similar to enamel in vertebrates, as Barbara Aichmayer and her colleagues at the Max Planck Institute in Potsdam in cooperation with Amir Berman and Amir Sagi of the Ben-Gurion University in Beer-Sheva have now discovered. "We assume," she explains, "that in the course of their evolution both vertebrates and freshwater crayfish developed enamel-like structures independently of one another. These amazing materials are a perfect answer to similar demands on the masticatory organs."

The enamel of freshwater crayfish is heavily fluoridated by nature

The mandibles of the freshwater crayfish are part of the cuticle which, as in other crustaceans, consists essentially of a network of chitin fibres. The shell is hardened in particular by disordered calcium carbonate, which is termed amorphous by scientists. In the mandibles of freshwater crayfish, the softer compound material of chitin and amorphous calcium carbonate, however, is covered with a thin layer which, like human enamel, is composed predominantly of crystalline calcium phosphate. This is remarkable because the constituent calcium phosphate is rarely found in the exoskeleton of invertebrates. The elongated shape of the crystals and their arrangement perpendicular to the surface of the teeth, too, match the structure of human enamel to a large extent and produces similar mechanical properties. The structure makes the material extremely hard and at the same time highly resistant to crack propagation, giving the tooth perfect protection against destruction.

However, there is one aspect in which the teeth of freshwater crayfish differ from those of vertebrates: Their enamel contains a high level of fluoride that makes it much less water-soluble -- all without taking fluoride tablets. In freshwater, the habitat of the freshwater crayfish, this is particularly important, because minerals containing calcium dissolve more easily there than in salt water.

Freshwater crayfish renew their enamel at a low metabolic cost

In human teeth, both the hard enamel on the crown and the underlying softer dentin are composed of calcium phosphate crystals. "Freshwater crayfish, on the other hand, are very economical with calcium phosphate, the production of which is for them metabolically much more costly than the construction of the rest of the cuticle," says Barbara Aichmayer. Freshwater crayfish renew their cuticle again and again as they grow. They dissolve the amorphous calcium carbonate out of the chitin tissue and partially store it in order to reuse it in the new shell. This is not possible with the crystalline calcium phosphate on their mandibles. They shed their costly enamel with the rest of the cuticle and build it completely anew. So in one respect, freshwater crayfish are way ahead of us. They renew their teeth at a low metabolic cost again and again, whereas our enamel, despite its hardness, gradually wears out and cannot be replaced.


Story Source:

The above story is based on materials provided by Max Planck Institute of Colloids and Interfaces. Note: Materials may be edited for content and length.


Journal Reference:

  1. Shmuel Bentov, Paul Zaslansky, Ali Al-Sawalmih, Admir Masic, Peter Fratzl, Amir Sagi, Amir Berman, Barbara Aichmayer. Enamel-like apatite crown covering amorphous mineral in a crayfish mandible. Nature Communications, 2012; 3: 839 DOI: 10.1038/ncomms1839

Cite This Page:

Max Planck Institute of Colloids and Interfaces. "A crowning success for crayfish." ScienceDaily. ScienceDaily, 18 May 2012. <www.sciencedaily.com/releases/2012/05/120518132412.htm>.
Max Planck Institute of Colloids and Interfaces. (2012, May 18). A crowning success for crayfish. ScienceDaily. Retrieved April 19, 2014 from www.sciencedaily.com/releases/2012/05/120518132412.htm
Max Planck Institute of Colloids and Interfaces. "A crowning success for crayfish." ScienceDaily. www.sciencedaily.com/releases/2012/05/120518132412.htm (accessed April 19, 2014).

Share This



More Earth & Climate News

Saturday, April 19, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Drought Concerns May Hurt Lake Tourism

Drought Concerns May Hurt Lake Tourism

AP (Apr. 18, 2014) Operators of recreational businesses on western reservoirs worry that ongoing drought concerns will keep boaters and other visitors from flocking to the popular summer attractions. (April 18) Video provided by AP
Powered by NewsLook.com
First Ever 'Female Penis' Discovered In Animal Kingdom

First Ever 'Female Penis' Discovered In Animal Kingdom

Newsy (Apr. 18, 2014) Not only are these newly discovered bugs' sex organs reversed, but they also mate for up to 70 hours. Video provided by Newsy
Powered by NewsLook.com
Ark. Man Finds 6-Carat Diamond At State Park

Ark. Man Finds 6-Carat Diamond At State Park

Newsy (Apr. 18, 2014) An Arkansas man has found a nearly 6.2-carat diamond, which he dubbed "The Limitless Diamond," at the Crater of Diamonds State Park. Video provided by Newsy
Powered by NewsLook.com
Deadly Avalanche Sweeps Slopes of Mount Everest

Deadly Avalanche Sweeps Slopes of Mount Everest

AP (Apr. 18, 2014) At least six Nepalese guides are dead after an avalanche swept the slopes of Mount Everest along a route used to climb the world's highest peak. (April 18) Video provided by AP
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