1. Department of Fibre and Polymer
Technology, Royal Institute of Technology, KTH, Teknikringen 56-58, SE-10044 Stockholm, Sweden
2. Instituto de Recursos Naturales
y Agrobiología de Sevilla, CSIC,
P.O. Box 1052, E-41080 Seville, Spain
3. Centro de Investigaciones Biológicas, CSIC, Ramiro de Maeztu 9, E-28040 Madrid, Spain