NEW^SfîatffiWffi MATERIALS
polymers and protein scaffolds, the researchers point out, and the excess copper in the worm's jaw could be playing that role. The jaw's impressive structural stability and resistance to abrasion approaches that of human tooth enamel, the team notes— even though atacamite makes up only 4% of the worm's jaw, while hydroxyapatite, C a ^ O ^ O H , makes up 96% of tooth enamel. nivorous worm uses the hard, This toughness is needed to prosharp-tipped structures to bite tect the jaw from wear and tear and inject venom into its prey as the worm burrows through T h e tip region of the jaws gritty marine sediment where it contains layers of polycrysmay chomp indiscriminately on talline atacamite fibrils disbits of gravel. persed in a protein matrix, the researchers find. T h e fibrils, G. dibranchiata appears to exwhich align with the jaw's outer hibit strict chemical control to contour, are about 80 nm in consistently produce only atadiameter and 1 — 10 |mm long. camite, rather than any of the othThey are concentrated toward er three known Cu2(OH)3Cl polythe center of the tip, while the morphs. The selectivity for copper base region is devoid of fibrils. rather than other elements such The hardness and stiffness of as calcium, silicon, and iron comthe jaw increases from the base monly found in biominerals sugto the tip and from the surface gests that copper may play an adto the interior, which correlates ditional role, such as activation of with the increasing degree of the worm's venom during injecmineralization. tion, the researchers say "The marriage of protein with Cross-sectional maps of copcopper mineral as well as with per and chloride concentration copper ions is an intriguing conconfirm the elemental distribucept per se, but may serve as a detion in the jaw and show that the sign prototype for new materials Cu-Cl ratio is higher than that that need to be hard, lightweight, found in atacamite, suggesting and durable," the researchers that free copper ions are present. write.—STEVE RITTER Copper is known to cross-link
SCIENCE
WORMS WITH A COPPER SMILE
Mineral composite in Glycera jaws imparts strength, abrasion resistance HE RARE MINERAL ATACA-
T
mite-Cu2(OH)3Cl-is named after the Atacama Desert in Chile, one of the few places where it is found. A team of U.S. and Austrian scientists has now found another source: the teethlike jaws of the marine bloodworm Glycera dibranchiata. The discovery by research associate Helga C. Lichtenegger of the department of chemistry and biochemistry at the University of California, Santa Barbara, and coworkers adds to the relatively short list of about 70 minerals that animals make to form structures such as shells, teeth, and bones. Atacamite is the first of these biominerals known to contain copper {Science, 298,389 (2002)}. Lichtenegger and her colleagues used a combination of X-ray diffraction, electron microscopy, and other techniques to determine the chemical composition and mechanical properties of the worm's jaws. The car-
METAL MOUTH A low degree of Cu2(OH)?Cl mineralization in a protein matrix yields a surprisingly strong material that makes up the 1.5-mm-long jaws of the bloodworm Glycera dibranchiata.
ACS
NEWS
Clean Up With National Chemistry Week
N
ext week—Oct. 20-26—is National Chemistry Week. NCW is a community-based program sponsored by the American Chemical Society that aims to unite all ACS local sections, industries, schools, and individuals in communicating the importance of chemistry to our quality of life. This year's NCW theme is "Chemistry Keeps Us Clean." The unifying event will be Chemistry Makes Cleaning Possible, a collection drive for personal hygiene products to benefit local food banks and charities. Student affiliate chapters and
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local sections will be collecting items such as soap, toothpaste, and shampoo to donate. "Clean" events will include sudsy fun demonstrations for K-12 students in Holland, Mich.; a soap, bubbles, and sparks magic show at the University of Tennessee, Knoxville; and hand-cleaning and graffiti prevention demonstrations at the Carnegie Science Center in Pittsburgh. This year, the American Chemistry Council partnered with ACS for NCW activities by sending out letters—about 3,200 in atl—to CEOs of its member
companies as well as to managers of their facilities inviting them to get their staffs involved in NCW. Lots of information about NCW and events planned by ACS local sections is on the Web at http://www.chemistry.org/ncw. ACS chair of the National Chemistry Week Task Force, W. H. (Jack) Breazeale of Mount Pleasant, S.C., says: "This will be the best NCW celebration ever. Everyone can have fun with the 'clean* theme. You can wash, wipe, and wax with this theme. You can grow and nurture with it also!"—LINDA RABER
HTTP://PUBS.ACS.ORG/CEN
