The mutagenic effects of non-lethal concentrations of lead(II) and mercury(II)

Journal Article · Wed Nov 01 04:00:00 EST 1995 · Environmental and Molecular Mutagenesis

OSTI ID:115111

Ariza, M A; Williams, M V ^[1]

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1. Ohio State Univ., Columbus, OH (United States)

Virtually nothing is known at the molecular level concerning the genotoxic effects following the acute exposure of cells to non-lethal concentrations of lead(II) or mercury(II). Possible health effects may be associated with such exposure. There are conflicting reports concerning the mutagenic properties of these metals. To determine if lead(II) and mercury(II) were mutagenic, we employed the transgenic Chinese hamster ovary cell line, AS52. Mutations in the gpt gene confer resistance to 6-thioguanine (TG) providing a selectable marker. Cells acutely exposed to lead (II) or mercury (II) (0.1-1 {mu}M) exhibited biphasic survival curves. There was little effect on viability of cells exposed to lead (II) or mercury (II) up to concentrations of 0.5 {mu}M (RCE; 96.1 {+-} 0.4%) and 0.3 {mu}M (RCE; 98 {+-} 0.1%) respectively. However, higher concentrations of the metals caused a significant increase in cell death. There was also a dose-dependent increase in the mutation frequency of the gpt gene in treated cells when compared to non-treated controls. Concentrations of the metals as low as 0.1 {mu}M caused a significant increase in the mutation frequency of the gpt gene when compared to the spontaneous mutation frequency observed in non-treated controls (6.71 {+-} 3.60 TG{sup r} mutants per 10{sup 6} clonable cells). The maximum increase in mutation frequency occurred in cells acutely exposed to a 1 {mu}M concentration of the metal (lead: 44.10 {+-} 8.6; mercury: 28.88 {+-} 5.39 TG{sup r} mutants per 10{sup 6} clonable cells). Preliminary studies, using PCR amplification, suggests that lead induces primarily deletion mutations (71%) while mercury (II) induces both point (44%) and deletion (55%) mutations in the gpt gene. While the molecular mechanism(s) by which lead and mercury (II) are genotoxic is unknown, the results of this study demonstrate that non-lethal concentrations of lead (II) and mercury (II) are mutagenic in eukaryotic cells.

• OSTI ID: 115111
• Report Number(s): CONF-9503160--
• Journal Information: Environmental and Molecular Mutagenesis, Journal Name: Environmental and Molecular Mutagenesis Journal Issue: Suppl.25 Vol. 25; ISSN 0893-6692; ISSN EMMUEG
• Country of Publication: United States
• Language: English

Related Subjects

56 BIOLOGY AND MEDICINE
APPLIED STUDIES
CHO CELLS
CHROMOSOMAL ABERRATIONS
GENE MUTATIONS
GENETIC EFFECTS
LEAD
MERCURY
MUTATION FREQUENCY