No evidence of expression of two classes of natural antibiotics (cathelicidins and defensins) in a sample of platypus milk
Camilla M. Whittington A , Julie A. Sharp B , Anthony Papenfuss C and Katherine Belov A DA Faculty of Veterinary Science, The University of Sydney, NSW 2006, Australia.
B Institute for Technology, Research & Innovation, Deakin University, Geelong, Vic. 3214, Australia.
C Bioinformatics Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, Vic. 3052, Australia.
D Corresponding author. Email: kbelov@vetsci.usyd.edu.au
Australian Journal of Zoology 57(4) 211-217 https://doi.org/10.1071/ZO09047
Submitted: 10 April 2009 Accepted: 31 August 2009 Published: 26 October 2009
Abstract
Marsupial neonates are born without a fully functioning immune system, and are known to be protected in part by natural antimicrobial peptides present in their mother’s milk. Monotreme neonates hatch at a similar stage in development, and it has been hypothesised that their survival in a non-sterile burrow also relies on the presence of natural antibiotics in their mother’s milk. Here we review the field of monotreme lactation and the antimicrobial peptide complement of the platypus (Ornithorhynchus anatinus). Using reverse transcriptase–polymerase chain reaction of milk cell RNA from a sample of platypus milk, we found no evidence for the expression of cathelicidins or defensins in the milk. This was unexpected. We hypothesise that these natural antibiotics may instead be produced by the young platypuses themselves.
Acknowledgements
The authors thank Tom Grant for providing the milk sample, and Erin Noonan, David Obendorf, Timothy Hore, and the Tasmanian Department of Primary Industries and Water for providing tissue and RNA samples. CW is supported by an Australian Postgraduate Award and a Fulbright Postgraduate Scholarship.
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