Institute Gustave Roussy, CNRS UMR 8121, University Paris 11, Villejuif, France, Institute of Medical Chemistry, University of Szeged, Szeged, Hungary, Department of Organic Chemistry, Institute of Chemistry, Eötvös Lóránd University, Budapest, Hungary, and Institute of Plant Biology, Institute of Biophysics, Biological Research Center, Szeged, Hungary (At 2009-06-25)