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Induction of mitotic segregation by chloromethanes and chloroethanes in Aspergillus nidulans
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The results show that the synthetic fec-12 is a potent direct clastogen in human lymphocytes. This is in accordance with findings with the Salmonella assay and suggests that this compound is a potential colonic carcinogen.
49 Lafi, A., and J.M. Parry, School of Biological Sciences, University College of Swansea, Swansea SA2 8PP (Great Britain) Spindle fidelity and the induction of structural and numerical chromosome aberrations in primary Chinese hamster cells after exposure to cigarette smoke condensate Cigarette smoke condensate (CSC) has been shown to be genotoxic in a variety of assay systems (for review see De Marini, 1983). We have undertaken a comparative study of the ability of CSC to induce aberrations of spindle fidelity and both numerical and structural chromosome aberrations in primary Chinese hamster (Luc 1) cells. Cells treated with CSC (up to 90 /~g/ml) show elevated levels of chromosome structural aberrations, endoreduplication and both hypodiploidy and hyperdiploidy. Structural aberrations and endoreduplication were induced in a linear dose-dependent manner over the concentration range tested. In contrast numerical aberrations showed a biphasic induction curve with a plateau of response at high doses. CSC exposure produced little or no modification of the fidelity of mitotic cell division spindle synthesis or dislocations of chromosomes from the spindle apparatus as measured by the use of the differential staining technique (Parry et al., 1982). Our data suggest that induced aneuploidy observed in Chinese hamster cells exposed to CSC is unlikely to result from chromosome structural damage, nuclear spindle damage or damage to the kinetochore. References De Marini, D.M. (1983) Mutation Res., 114, 59-89. Parry, E.M., N. Danford and J.M. Parry (1982) Mutation Res., 105, 243-252.
50 Crebelli, R., J. Franekic 1, R. Benigni, G. Conti, L. Conti and A. Carere, Istituto Superiore di Sanith, Rome (Italy), and a Faculty of Food and Biotechnology, Zagreb (Yugoslavia) Induction of mitotic segregation by chloromethanes and chloroethanes in Aspergillus nidulans Several chloromethanes and chloroethanes were assayed for their ability to induce mitotic segregation in A. nidulans. All tested chemicals turned out to be active, to various degrees, in a narrow range of concentrations. Active doses were immediately below the concentration arresting conidial germination and nuclear division. Among the halomethanes assayed, CC14 was the most active (LEC 0.04% v/v), increasing up to 10-fold the spontaneous frequency of mitotic segregants. Chloroform and CHzC12 were similarly active (ca. 5-fold increases) at higher concentrations (LEC 0.16 and 0.4%, respectively). Among the haloethanes, 1,2-dichloroethane and 1,1-dichloroethane showed identical cytotoxic and cytostatic properties and were active in the same range of concentrations (0.2-0.3%) but exerted different mutagenic potencies, the former increasing the spontaneous frequencies up to 30-fold and the latter being only borderline active. Mutagenic potencies of tested chemicals were poorly correlated with log P, melting point and MW but showed a significant correlation with the refractive index.
51 Crebelli, R., G. Conti and A. Carere, Istituto Superiore di SanitY, Rome (Italy) Hydroxybenzene induction of mitotic segregation in Aspergillus nidulans Hydroquinone, catechol and phenol, the principal hydroxy metabolites of benzene, were assayed in tests for mitotic segregation induction in Aspergillus nidulans diploid strain 19. Hydroquinone was the most active chemical, increasing up to 10-fold the frequency of mitotic segregants at 1-3 mM. Catechol was similarly active at 10-20
The results show that the synthetic fec-12 is a potent direct clastogen in human lymphocytes. This is in accordance with findings with the Salmonella assay and suggests that this compound is a potential colonic carcinogen.
49 Lafi, A., and J.M. Parry, School of Biological Sciences, University College of Swansea, Swansea SA2 8PP (Great Britain) Spindle fidelity and the induction of structural and numerical chromosome aberrations in primary Chinese hamster cells after exposure to cigarette smoke condensate Cigarette smoke condensate (CSC) has been shown to be genotoxic in a variety of assay systems (for review see De Marini, 1983). We have undertaken a comparative study of the ability of CSC to induce aberrations of spindle fidelity and both numerical and structural chromosome aberrations in primary Chinese hamster (Luc 1) cells. Cells treated with CSC (up to 90 /~g/ml) show elevated levels of chromosome structural aberrations, endoreduplication and both hypodiploidy and hyperdiploidy. Structural aberrations and endoreduplication were induced in a linear dose-dependent manner over the concentration range tested. In contrast numerical aberrations showed a biphasic induction curve with a plateau of response at high doses. CSC exposure produced little or no modification of the fidelity of mitotic cell division spindle synthesis or dislocations of chromosomes from the spindle apparatus as measured by the use of the differential staining technique (Parry et al., 1982). Our data suggest that induced aneuploidy observed in Chinese hamster cells exposed to CSC is unlikely to result from chromosome structural damage, nuclear spindle damage or damage to the kinetochore. References De Marini, D.M. (1983) Mutation Res., 114, 59-89. Parry, E.M., N. Danford and J.M. Parry (1982) Mutation Res., 105, 243-252.
50 Crebelli, R., J. Franekic 1, R. Benigni, G. Conti, L. Conti and A. Carere, Istituto Superiore di Sanith, Rome (Italy), and a Faculty of Food and Biotechnology, Zagreb (Yugoslavia) Induction of mitotic segregation by chloromethanes and chloroethanes in Aspergillus nidulans Several chloromethanes and chloroethanes were assayed for their ability to induce mitotic segregation in A. nidulans. All tested chemicals turned out to be active, to various degrees, in a narrow range of concentrations. Active doses were immediately below the concentration arresting conidial germination and nuclear division. Among the halomethanes assayed, CC14 was the most active (LEC 0.04% v/v), increasing up to 10-fold the spontaneous frequency of mitotic segregants. Chloroform and CHzC12 were similarly active (ca. 5-fold increases) at higher concentrations (LEC 0.16 and 0.4%, respectively). Among the haloethanes, 1,2-dichloroethane and 1,1-dichloroethane showed identical cytotoxic and cytostatic properties and were active in the same range of concentrations (0.2-0.3%) but exerted different mutagenic potencies, the former increasing the spontaneous frequencies up to 30-fold and the latter being only borderline active. Mutagenic potencies of tested chemicals were poorly correlated with log P, melting point and MW but showed a significant correlation with the refractive index.
51 Crebelli, R., G. Conti and A. Carere, Istituto Superiore di SanitY, Rome (Italy) Hydroxybenzene induction of mitotic segregation in Aspergillus nidulans Hydroquinone, catechol and phenol, the principal hydroxy metabolites of benzene, were assayed in tests for mitotic segregation induction in Aspergillus nidulans diploid strain 19. Hydroquinone was the most active chemical, increasing up to 10-fold the frequency of mitotic segregants at 1-3 mM. Catechol was similarly active at 10-20