Stinky frogs are a treasure trove of antibiotic substances

Nov 30, 2011
Stinky frogs are a treasure trove of antibiotic substances

Some of the nastiest smelling creatures on Earth have skin that produces the greatest known variety of anti-bacterial substances that hold promise for becoming new weapons in the battle against antibiotic-resistant infections, scientists are reporting. Their research on amphibians so smelly (like rotten fish, for instance) that scientists term them "odorous frogs" appears in ACS' Journal of Proteome Research.

Yun Zhang, Wen-Hui Lee and Xinwang Yang explain that scientists long have recognized frogs' skin as a rich potential source of new antibiotics. Frogs live in warm, wet places where bacteria thrive and have adapted skin that secretes chemicals, known as peptides, to protect themselves from infections. Zhang's group wanted to identify the specific (AMPs), and the most potent to give scientists clues for developing .

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 also activating the immune system to assist in the battle.

Explore further: New England Aquarium offering penguins 'honeymoon suites'

More information: "Extremely Abundant Antimicrobial Peptides Existed in the Skins of Nine Kinds of Chinese Odorous Frogs" J. Proteome Res., Article ASAP. DOI: 10.1021/pr200782u

Abstract
Peptide agents are regarded as hopeful candidates to solve life-threatening resistance of pathogenic microorganisms to classic antibiotics due to their unique action mechanisms. Peptidomic and genomic investigation of natural antimicrobial peptides (AMPs) from amphibian skin secretions can provide a large amount of structure–functional information to design peptide antibiotics with therapeutic potential. In the present study, we identified a large number of AMPs from the skins of nine kinds of Chinese odorous frogs. Eighty AMPs were purified from three different odorous frogs and confirmed by peptidomic analysis. Our results indicated that post-translational modification of AMPs rarely happened in odorous frogs. cDNAs encoding precursors of 728 AMPs, including all the precursors of the confirmed 80 native peptides, were cloned from the constructed AMP cDNA libraries of nine Chinese odorous frogs. On the basis of the sequence similarity of deduced mature peptides, these 728 AMPs were grouped into 97 different families in which 71 novel families were identified. Out of these 728 AMPs, 662 AMPs were novel and 28 AMPs were reported previously in other frog species. Our results revealed that identical AMPs were widely distributed in odorous frogs; 49 presently identified AMPs could find their identical molecules in different amphibian species. Purified peptides showed strong antimicrobial activities against 4 tested microbe strains. Twenty-three deduced peptides were synthesized and their bioactivities, including antimicrobial, antioxidant, hemolytic, immunomodulatory and insulin-releasing activities, were evaluated. Our findings demonstrate the extreme diversity of AMPs in amphibian skins and provide plenty of templates to develop novel peptide antibiotics.

Related Stories

Frog plus frying pan equals better antibiotic

Aug 20, 2007

By creating "Teflon" versions of natural antibiotics found in frog skin, a research team led by biological chemist E. Neil Marsh has made the potential drugs better at thwarting bacterial defenses, an improvement that could ...

Recommended for you

Telling the time of day by color

Apr 17, 2015

Research by scientists at The University of Manchester has revealed that the colour of light has a major impact on how the brain clock measures time of day and on how the animals' physiology and behavior adjust accordingly. ...

Aphrodisiac for fish and frogs discovered

Apr 17, 2015

A supplement simply added to water has been shown to boost reproduction in nematodes (roundworms), molluscs, fish and frogs – and researchers believe it could work for humans too.

Evolution puts checks on virgin births

Apr 17, 2015

It seems unnatural that a species could survive without having sex. Yet over the ages, evolution has endowed females of certain species of amphibians, reptiles and fish with the ability to clone themselves, ...

Humans can't resist those puppy-dog eyes

Apr 16, 2015

When humans and their four-legged, furry best friends look into one another's eyes, there is biological evidence that their bond strengthens, researchers report.

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.