Francesco RENZI, PhD Research Associate from the F.R.S.-FNRS Research Unit in Biology of Microorganisms (URBM) Université de Namur ASBL Rue de Bruxelles 61 - 5000 Namur Belgique T. +32 (0)81 724 401 F. +32 (0)81 724 420 francesco.renzi@unamur.be