1 Molecular Microbiology and Biotechnology, Institute of Biology Leiden, Leiden University, Sylviusweg 72, 2333, BE, Leiden, The Netherlands.
2 Dutch DNA Biotech, Hugo R Kruytgebouw 4-Noord, Padualaan 8, 3584, CH, Utrecht, The Netherlands.
3 Molecular Microbiology and Biotechnology, Institute of Biology Leiden, Leiden University, Sylviusweg 72, 2333, BE, Leiden, The Netherlands. a.f.j.ram@biology.leidenuniv.nl.