News From The American Chemical Society, 3-Nov-2008

Tiny DNA tweezers can catch and release objects on-demand



Researchers in China are reporting development of a new DNA "tweezers" that are the first of their kind capable of grasping and releasing objects on-demand. The microscopic tweezers could have several potential uses, the researchers note. Those include microsurgery, drug and gene delivery for gene therapy, and in the manufacturing of nano-sized circuits for futuristic electronics. Their study is scheduled for the November 12 issue of the weekly Journal of the American Chemical Society.



Zhaoxiang Deng and colleagues note that other scientists have developed tweezers made of DNA, the double helix molecule and chemical blueprint of life. Those tweezers can open and close by responding to complementary chemical components found in DNA's backbone. However, getting the tweezers to grasp and release objects like real tweezers has remained a bioengineering challenge until now.



The scientists describe development of a pair of DNA tweezers composed of four DNA strands - three which act as the "arms." In laboratory studies, the scientists showed that they could grab a piece of target DNA in the arms of the tweezers and release it on-demand using a controlled series of hydrogen bonding and pH changes. The scientists used fluorescent gel imaging to confirm the effectiveness of the tweezers' operation. - MTS



ARTICLE: "Catch and Release: DNA Tweezers that Can Capture, Hold, and Release an Object under Control"



DOWNLOAD FULL TEXT ARTICLE: dx.doi/10.1021/ja805945r



CONTACT:

Zhaoxiang Deng, Ph.D.

University of Science and Technology of China

Anhui, China



DNA fingerprinting method may thwart false labeling of shark meat



Researchers in Spain are reporting that a new DNA identification method could thwart false labeling of shark species used in various seafood products, including the expensive Chinese delicacy known as shark fin soup. Their study is scheduled for the November 26 issue of ACS' Journal of Agricultural and Food Chemistry, a bi-weekly publication.



Maria Blanco, Ricardo Perez-Martin, and Carmen G. Sotelo note that consumption of shark meat appears to be on the rise worldwide, with some seafood companies reportedly having substituted cheaper shark species for more expensive species and incorrectly labeling their products. European Union regulations now require listing the species name on shark products to avoid fraud and to help conserve certain shark species. However, a fast, reliable method for distinguishing between different species of shark remains elusive.



The scientists describe the use of a relatively new technique called forensically informative nucleotide sequencing (FINS), in which DNA isolated from unknown biologic samples is compared to a database of DNA markers from known species. In the new study, the scientists collected DNA markers from nine different commercial seafood samples containing shark meat and compared them to known DNA markers from 23 different shark species. The scientists found that two of the nine shark products analyzed had been labeled with incorrect species names, demonstrating the effectiveness for the FINS method. - MTS



ARTICLE: "Identification of Shark Species in Seafood Products by Forensically Informative Nucleotide Sequencing"



DOWNLOAD FULL TEXT ARTICLE: dx.doi/10.1021/jf8015128



CONTACT:

Maria Blanco, Ph.D.

Consejo Superior de Investigaciones Cientificas (CSIC)

Vigo, Spain







The American Chemical Society - the world's largest scientific society - is a nonprofit organization chartered by the U.S. Congress and a global leader in providing access to chemistry-related research through its multiple databases, peer-reviewed journals and scientific conferences. Its main offices are in Washington, D.C., and Columbus, Ohio.



Source: Michael Woods


American Chemical Society