School of Biochemistry & Molecular Biology, University of New South Wales, Sydney 2052, , Australia1
School of Science, University of Western Sydney Nepean, Kingswood 2747, , Australia2
For correspondence. Giancarlo A. Biagini. Tel: +61 2 9385 2043. Fax: +61 2 9385 1483. e-mail: g.biagini{at}unsw.edu.au