title: On the mode of action of N-phenyl-2-naphthylamine in plants.
abstract: N-phenyl-2-naphthylamine, a sediment contaminant previously identified as a major toxicant of site-specific importance was investigated for its mode of toxic action. From short-term bioassays with daphnids, fish eggs, bacteria, and algae it appears that this compound has specific phytotoxic properties at concentrations below 100 microg/L, which cannot be explained assuming an unspecific narcosis type of action in plants. Also, hydroxy-, nitro-, and methylderivatives show clear excess toxicity as compared to baseline toxic effects. Of several plant-specific growth and development processes investigated, only photosynthesis could be demonstrated to be affected at short exposure times and low concentrations. Disturbance of primary photosynthetic reactions such as oxygen evolution and fluorescence quenching, however, becomes only apparent after 2-3 h of exposure, which is in sharp contrast to known specific inhibitors targeting processes such as electron transport or ATP production. This, and concentration-time-effect modeling lead to the suggestion that N-phenyl-2-naphthylamine acts intracellular as a reactive compound in cell membranes producing irreversible, and thus cumulative, damage over time in algae. The effects may become first apparent in membrane-rich compartments such as the algal chloroplast.
authors.affiliation: UFZ Centre for Environmental Research Leipzig-Halle, Germany. rolf.altenburger@ufz.de
authors.forename: Rolf
authors.initials: R
authors.lastname: Altenburger
authors.forename: Werner
authors.initials: W
authors.lastname: Brack
authors.forename: William R
authors.initials: WR
authors.lastname: Greco
authors.forename: Matthias
authors.initials: M
authors.lastname: Grote
authors.forename: Klaus
authors.initials: K
authors.lastname: Jung
authors.forename: Agnes
authors.initials: A
authors.lastname: Ovari
authors.forename: Janet
authors.initials: J
authors.lastname: Riedl
authors.forename: Katrin
authors.initials: K
authors.lastname: Schwab
authors.forename: Eberhard
authors.initials: E
authors.lastname: Küster
mesh_terms: D015081:2-Naphthylamine / Q000031:analogs & derivatives* / Q000633:toxicity; D048908:Aliivibrio fischeri / Q000187:drug effects / Q000502:physiology; D000818:Animals; D000460:Chlorophyta / Q000187:drug effects* / Q000502:physiology; D003621:Daphnia / Q000187:drug effects / Q000502:physiology; D010788:Photosynthesis / Q000187:drug effects; D012098:Reproduction / Q000187:drug effects; D015027:Zebrafish / Q000502:physiology
chemical_list: C011948:neozone; D015081:2-Naphthylamine