Thursday, 15 March 2012

Antimicrobial peptides in the tammar wallaby found to be effective at killing Superbugs

The rise of drug resistant bacteria has resulted in the need for the development of new antimicrobial drugs. But could a more natural solution be found? Natural animal antibiotics, like those found in the tammar wallaby, may provide a new method for combating superbugs.

Tammar wallaby (Photo from ARC centre for Kangaroo Genomics)

The tammar wallaby, Macropus eugenii, is a member of the kangaroo family inhabiting Kangaroo Island in South Australia, a number of islands off the coast of Western Australia and a small area on the south-west of the Australian mainland. Tammar wallabies give birth to their young after a very short gestation period of only 26.5 days. The young then reside in the mother’s pouch for another 9 to 10 months. Unlike humans, where the embryo develops in a relatively sterile uterus for nine months, the joey is immediately exposed to various bacteria found in the pouch of the mother. In the early stages of life the joey’s immune system is not fully developed and the joey must rely on the bacteria fighting properties found in its mother’s milk.

A study conducted in 2011 sequenced the wallaby’s genome and uncovered eight genes which encode antimicrobial peptides, essential for the immune system of young wallabies during the early stages of birth. Antimicrobial peptides are defensive proteins which are released by the body on invasion of a pathogen. The peptides attack the pathogen and stop reproduction.
A group of scientists questioned whether these peptides could be used to fight drug resistant bacteria in humans. Using peptides from the tammar wallaby, experiments were conducted on various bacteria and found one specific peptide to be 10 times more effective at killing the bacteria E.coli than other commonly used antibiotics. More interestingly, 3 multi-drug resistant bacteria were also able to be killed by this same peptide. Further testing found that the peptide was not destructive towards human blood cells and therefore could possibly be used within humans as a natural method to combat bacteria.

The rise of drug resistant bacteria results in the inability to cure certain diseases in humans and a need to find and develop new antimicrobial drugs. Natural animal antibiotics, like those found in the tammar wallaby, may provide a new method for combating such diseases in the future.

References
Reece, J. B. et al., 2011. Campbell Biology. 9th (Australian Version) ed. Pearson Australia Group Pty Ltd.

Renfree, M. B. & Papenfuss, A. T., 2011. Genome sequence of an Australian kangaroo, Macropus eugenii, provides insight into the evolution of mammalian reproduction and development. Genome Biology, 12(8), p. 123.
Wang, J. et al., 2011. Ancient Antimicrobial Peptides Kill Antibiotic-Resistant Pathogens: Australian Mammals Provide New Options. PLoS ONE, 6(8), p. e24030.

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