Friday, December 9, 2011

Odorrana Frogs as a Source for New Antibiotics

The  Chinese Odorrana tormota. Photo Credit 
Albert Feng
About 45 species of ranid frogs are currently recognized in the genus Odorrana, they inhabit high-gradient streams in Asia from Myanmar and Thailand and Malaya southward through the Sunda Shelf (Sumatra to Borneo) and eastward into China and Japan. And at least some species use ultrasonic sound to communicate through the noise of running water. Now, Yang et al. (2011) find that they may produce the greatest known variety of anti-bacterial substances known, and that they hold promise for becoming new weapons in the battle against antibiotic-resistant infections. The dorous frogs have been described as smelling like decomposing flesh. Zhang's research group at the Kunming Institute of Zoology, of the Chinese Academy worked to identify the specific antimicrobial peptides (AMPs) for developing new antibiotics. They identified more than 700 of these substances from nine species of odorous frogs and concluded that the AMPs account for almost one-third of all AMPs found in the world, the greatest known diversity of these germ-killing chemicals. Interestingly, some of the AMPs have a dual action, killing bacteria directly and simultaneouly activating the immune system. Their results sugest that identical AMPs were widely distributed in odorous frogs; 49 known AMPs can be found in different amphibian species. Purified peptides showed a strong and effective antimicrobial activity against four tested strains of microbe. They synthesized another 23 peptides and evaluated their antimicrobial, antioxidant, hemolytic, immunomodulatory and insulin-releasing properties. Their research demonstrates the extreme diversity of AMPs in amphibian skins and provides numerous templates for developing novel peptide antibiotics. Thus, we have yet another reason to protect biodiversity.

Xinwang Yang, Wen-Hui Lee, Yun Zhang. 2011. Extremely Abundant Antimicrobial Peptides Existed in the Skins of Nine Kinds of Chinese Odorous Frogs. Journal of Proteome Research, 2011: 111118134814004 DOI: 10.1021/pr200782u

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