1. Departments of Biology and of Biochemistry and Pharmacy, Åbo Akademi University, BioCity, Tykistökatu 6A, 20520 Turku, Department of Biochemistry and Food Chemistry, University of Turku, Vatselankatu 2, 20014 Turku, and Institute of Occupational Health, Hämeenkatu 10, 20500 Turku, Finland