1. Division of Pharmacognosy, Department of Medicinal Chemistry, Biomedical Center, Uppsala University, Box 574, SE-751 23 Uppsala, Sweden
2. Department of Marine Ecology, Tjärnö Marine Biological Laboratory, University of Gothenburg, SE- 452 96 Strömstad, Sweden
3. Swedish Board of Fisheries, Ekelundsgatan 1, Box 423, SE-401 26 Göteborg, Sweden