title: Dichlorophenylurea-resistant oxygen evolution in Chlorella after cerulenin treatment.
abstract: Fluorescence spectra at 77 K, oxygen evolution at 30 degrees C and delayed fluorescence at 25 degrees C were measured in Chlorella pyrenoidosa cultures with and without cerulenin and subsequent 3-(3,4-dichlorophenyl)-1,1-dimethyl-urea (DCMU) treatment, respectively. In pure algal cultures the oxygen evolution was inhibited by DCMU and the long-time component of fluorescence was highly influenced by DCMU, as expected. In contrast, both oxygen evolution and delayed fluorescence became DCMU-resistant in cerulenin-treated cultures. The DCMU-resistance is correlated with a change in the fatty acid distribution of the thylakoid membrane, which also leads to changes in the prompt fluorescence. Cerulenin appears to be a promising new tool of diagnostics for the hitherto unsatisfactorily understood processes of oxygen evolution in photosynthesizing organisms.
mesh_terms: D000935:Antifungal Agents / Q000494:pharmacology*; D002569:Cerulenin / Q000494:pharmacology*; D002708:Chlorella / Q000187:drug effects* / Q000378:metabolism / Q000502:physiology; D004237:Diuron / Q000494:pharmacology*; D005227:Fatty Acids / Q000378:metabolism; D005453:Fluorescence; D010100:Oxygen / Q000378:metabolism*; D010788:Photosynthesis / Q000187:drug effects
chemical_list: D000935:Antifungal Agents; D005227:Fatty Acids; D002569:Cerulenin; D004237:Diuron; D010100:Oxygen