1. Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, and Center for Biomolecules and Complex Molecular Systems, Flemingovo nám. 2,16610 Prague 6, Czech Republic, Department of Food Sciences, Stocking Hall, Cornell University, Ithaca, New York 14853, and Center of Marine Biotechnology and Medical Biotechnology Center, University of Maryland Biotechnology Institute, 725 West Lombard, Baltimore, Maryland 21201