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Studies on the chromosome-damaging effect of some pyrrolizidine alkaloids in human lymphocytes in vitro
276 The frequencies of chromatid interchanges and micronuclei are suitable indicators of the modifying effect of anticlastogens. The outcome of the SCE test showed clear differences from that of analysis of chromosome breakage or micronucleus in anticlastogen studies. (Supported by grants of the Minister of Research and Technology of the Federal Republic of Germany.)
3 Behm, C., W. v o n d e r Hude, R. Gfirtler, G. Graupner and A. Basler, Max von Pettenkofer-Institut des Bundesgesundheitsamtes, Postfach 33 00 13, D-1000 Berlin 33 (F.R.G.) Evaluation of the S O S chromotest The SOS chromotest is an elegant method for measuring the induction of an SOS function in E. coli. The main values of this assay are its technical simplicity and the short time required to complete the test. Initial results have shown that most genotoxic compounds are also SOS inducers. The purpose of the present investigation was to evaluate the validity of this short-term test to identify chemical mutagens. We examined 113 compounds of various chemical classes with the SOS chromotest. Their responses were compared to published data obtained with the Salmonella/microsome assay (n = 104). The following conclusions are drawn: 32 of 104 compounds were negative and 33 substances were positive in both test systems. One chemical (quinoline 1-oxide) yielded positive results only in the SOS chromotest. However, there are genotoxic substances of some chemical classes which are not SOS inducers (n = 38). Conflicting results in the two tests were obtained especially with azo compounds (all are negative in the SOS chromotest), most aromatic amines and acridines and some halogenated substances. Testing of oxidative mutagens in the Ames test is problematic, because the appropriate strain TA102 has extremely high and variable numbers of spontaneous revertants. Only few substances of this chemical class have been tested in the SOS chromotest. The results were clear-cut positive.
The data indicate that the SOS chromotest has practical advantages, it may be used as a primary screening assay for testing mutagens, and also instead of strain TA102 in the Ames test to investigate oxidative mutagens. The assay may be performed as part of a battery of short-term tests, but cannot replace the Salmonella/microsome assay with all of its strains.
4 Behninger, C., Institut fi~r Botanik und Pharmazeutische Biologie der Universitfit Erlangen-N~rnberg, Staudtstrasse 5, D-8520 Erlangen (F.R.G.) Studies on the chromosome-damaging effect of some pyrrolizidine alkaloids in human lymphocytes in vitro The chromosome-damaging effect of the pyrrolizidine alkaloids heliotrine, senkirkine and tussilagine was investigated in human lymphocyte cultures. At a concentration of 100/~M heliotrine induced structural c h r o m o s o m e aberrations. Senkirkine and tussilagine, the main alkaloids of coltsfoot (Tussilago farfara) did not enhance the number of structural chromosome aberrations. Furthermore an alkaloid crude extract of comfrey (Syrnphytum officinale) was analysed to see if it induced sister-chromatid exchanges (SCE) in human lymphocytes in vitro. Additionally the influence of rat liver enzymes ($9) was tested. The alkaloid extract alone induced up to 25 SCE/metaphase at a final concentration of 1400 /~g/ml. The simultaneous application of $9 mix led to a dose-dependent increase of the SCE rate up to nearly 50 induced SCE/metaphase. The enhancement of the SCE rate depended also on the protein concentrations of the $9 mix used. These results show that for further estimations of pyrrolizidine alkaloids in human lymphocytes the influence of an external metabolic activation system must be considered.
5 Br~derlein, S., K. Diirsch, R. Istel and E. Gebhart, Institut fiir Humangenetik der Universit~it, Schwabachanlage 10, D-8520 Erlangen (F.R.G.)
3 Behm, C., W. v o n d e r Hude, R. Gfirtler, G. Graupner and A. Basler, Max von Pettenkofer-Institut des Bundesgesundheitsamtes, Postfach 33 00 13, D-1000 Berlin 33 (F.R.G.) Evaluation of the S O S chromotest The SOS chromotest is an elegant method for measuring the induction of an SOS function in E. coli. The main values of this assay are its technical simplicity and the short time required to complete the test. Initial results have shown that most genotoxic compounds are also SOS inducers. The purpose of the present investigation was to evaluate the validity of this short-term test to identify chemical mutagens. We examined 113 compounds of various chemical classes with the SOS chromotest. Their responses were compared to published data obtained with the Salmonella/microsome assay (n = 104). The following conclusions are drawn: 32 of 104 compounds were negative and 33 substances were positive in both test systems. One chemical (quinoline 1-oxide) yielded positive results only in the SOS chromotest. However, there are genotoxic substances of some chemical classes which are not SOS inducers (n = 38). Conflicting results in the two tests were obtained especially with azo compounds (all are negative in the SOS chromotest), most aromatic amines and acridines and some halogenated substances. Testing of oxidative mutagens in the Ames test is problematic, because the appropriate strain TA102 has extremely high and variable numbers of spontaneous revertants. Only few substances of this chemical class have been tested in the SOS chromotest. The results were clear-cut positive.
The data indicate that the SOS chromotest has practical advantages, it may be used as a primary screening assay for testing mutagens, and also instead of strain TA102 in the Ames test to investigate oxidative mutagens. The assay may be performed as part of a battery of short-term tests, but cannot replace the Salmonella/microsome assay with all of its strains.
4 Behninger, C., Institut fi~r Botanik und Pharmazeutische Biologie der Universitfit Erlangen-N~rnberg, Staudtstrasse 5, D-8520 Erlangen (F.R.G.) Studies on the chromosome-damaging effect of some pyrrolizidine alkaloids in human lymphocytes in vitro The chromosome-damaging effect of the pyrrolizidine alkaloids heliotrine, senkirkine and tussilagine was investigated in human lymphocyte cultures. At a concentration of 100/~M heliotrine induced structural c h r o m o s o m e aberrations. Senkirkine and tussilagine, the main alkaloids of coltsfoot (Tussilago farfara) did not enhance the number of structural chromosome aberrations. Furthermore an alkaloid crude extract of comfrey (Syrnphytum officinale) was analysed to see if it induced sister-chromatid exchanges (SCE) in human lymphocytes in vitro. Additionally the influence of rat liver enzymes ($9) was tested. The alkaloid extract alone induced up to 25 SCE/metaphase at a final concentration of 1400 /~g/ml. The simultaneous application of $9 mix led to a dose-dependent increase of the SCE rate up to nearly 50 induced SCE/metaphase. The enhancement of the SCE rate depended also on the protein concentrations of the $9 mix used. These results show that for further estimations of pyrrolizidine alkaloids in human lymphocytes the influence of an external metabolic activation system must be considered.
5 Br~derlein, S., K. Diirsch, R. Istel and E. Gebhart, Institut fiir Humangenetik der Universit~it, Schwabachanlage 10, D-8520 Erlangen (F.R.G.)