or MNNG in theet assay after 4 h and 8 h of exposu respectively. Where the respective effect level was reached in multiple experimen standard deviations are given in brackets MNNG Abiraterone MMS .Almost all concentrations of MMS showed signi ant effects . The strongest effect was found at mg L . Using the tail mome the LOEC for MMS after 8 h of exposure was determined at mg L with an induction factor of .
For M several GeneTEQs x were determined . The calculation of the GeneTEQ 0 for MMS is exemplid in relation to the MNNG tail moment after 4 h of exposure: log EC 0MNNG log mg L / EC 0MNNG mg L GeneTEQ 0 EC Icariin phosphodiesterase(pde) inhibitor 0 /EC 0MNNG mg L mg L In the literatu there are no data for in vitro exposure of sh cells to CPP and MNU. For the other genotoxi knowledge about cytoand genotoxicity in sh or sh cell systems is very scarce. In theet ass DMNA was tested in vitro by Schnurstein 8 using primary hepatocytes and gill cells from zebra sh . Within a concentration range similar to the present stu very low effects and no clear concentrationresponse relationship were found. This conms the data of the present study which also revealed only minor genotoxic effects of DMNA.
In aet assay study on M De Miranda Cabral Gontijo exposed erythrocytes of Nile tilapia in vitro to MMS concentrations signi antly higher than in the present study and found a clear concentrationrelated effect. 7 In the present stu there was a clear tendency for an increase of effect of MMS. Howev given the increasing interference with cytotoxici it would not have been reasonable Camptothecin 7689034 to test higher concentrations with RTL cells. In the literatu strong genotoxic effects by NQO were found in mammalian as well as in zebra sh hepatocytes and gill cells after in vitro exposu however while testing higher concentrations than in the present study. In fa in the present stu genotoxicity of NQO may have been masked by the fact that RTL cells proved to be quite sensitive for cytotoxicity caused by NQO.
4 Th since NQO showed considerable cytotoxici but failed to cause suf iently high buy Fisetin J. Environ. Monit. genotoxic effec it was also not deemed suitable as a reference organizing center substance for the GeneTEQ concept with RTL cells. For genotoxici equivalent concentrations can easily be calculated analogously to the BioTEQ concept for dioxinlike activity using TEFs and REPs. Therefo the GeneTEQ is standardized for a given volume and a certain effect level . For instan mg L MNNG exerted a genotoxic effect equivalent to that of mg L MNU. In Tables and , it is noticeable that for several pure substances and extracts at some effect levels high standard deviations were calculated. This is due to the fact that the GeneTEQs given are calculated based on all experimen so that data arebined from experiments wherein the tail moment or the percentage of tail DNA reached the regarded effect levels of of the maximum.