jueves, 29 de septiembre de 2011

Fifty-Nine-Million Year Old Protein Resurrected --A Potent Antibiotic


Ben Cocks, Research Director of the Bio-Sciences Research and a Professor in Animal Genetics and Genomics at La Trobe University has been working with DNA from a 60 million year-old wallaby to combat drug-resistant bugs or pathogens. The wallaby genome was recently published, and identified a number of genes encoding anti-microbial peptides. The team reconstructed what a certain segment of DNA would have looked like 60 million years ago when Australia was part of Gondwana.

Cocks team fovused on the immunity that are in platypus and wallabies because both these animals can't make antibodies until they're, in the case of the wallaby, a hundred days old, yet they're able to avoid infection for example, in the pouch, which has lots of microbes. They wanted to discover what was giving the animals this type of immunity from the bacteria. It turns out that they do have these antimicrobial peptides and in the genome we can actually see the many different versions of these antimicrobial genes.

The found out that wallaby milk in the early stages of lactation, is very potent against multi-drug-resistant bacteria and in fact up to ten times more potent than drugs like tetracycline and ampicillin and we've actually tested the clinical isolates from Australian and American hospitals which are actually resistant to all available antibiotics, and the peptides were very effective against those particular bacteria.

It's hard to know what the full context of the gene is in that time frame and the animal that is closest to that ancestor is djarthia which has been identified fossils that are 55 million years old in Tingamarra in Queensland. These animals are small possum-like animals and appear to share features that indicate that their potential ancestor and Michael Archer's group at the University of New South Wales has discovered these animals, whih  would have had a unique set of immune functions.


Cocks' study is potentially it is a first step similar to Marilyn Renfree's group at the University of Melbourne who were actually able to take a Tasmanian Tiger gene and have it expressed in a tissue-specific manner in a mouse, so you could actually combine that idea with computationally re-creating ancient genes.

The practical application is obviously the multi-drug-resistant bacteria where there's a possibility the peptides could be developed as an intravenous for people having infections that are resistant to available antibiotics.

Source: The Daily Galaxy 

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