1. Department of Organic Chemistry, University of Granada, Avdn. Fuentenueva, Spain, Mycology Group, BioCentrum-DTU, Søltofts Plads, Technical University of Denmark, 2800 Lyngby, Denmark, Carlsberg Laboratory, Gamle Carlsberg Vej 10, DK-2500 Valby, Denmark, and Marine Chemistry Section, The H.C.Ø. Institute, University of Copenhagen, DK-2100 Copenhagen, Denmark