Mutagenicity of inorganic compounds in Salmonella typhimurium: arsenic, chromium and selenium

Löfroth, Göran; Ames, B. N.

doi:10.1016/0165-1161(78)90379-5

Cited by 68 publications

(44 citation statements)

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“…This solubility also promotes the active transport of chromate across biological membranes (7), and once internalized by cells, Cr(VI) exhibits a variety of toxic, mutagenic, and carcinogenic effects (34,44). In contrast, most cells are impermeable to Cr(III), which is insoluble under typical environmental conditions (30); as measured by the Ames test, it is therefore some 1,000-fold less mutagenic than Cr(VI) (19). Thus, strategies for decontamination of environmental chromate focus on reducing it to Cr(III).…”

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confidence: 99%

Effect of Chromate Stress on Escherichia coli K-12

et al. 2006

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The nature of the stress experienced by Escherichia coli K-12 exposed to chromate, and mechanisms that may enable cells to withstand this stress, were examined. Cells that had been preadapted by overnight growth in the presence of chromate were less stressed than nonadapted controls. Within 3 h of chromate exposure, the latter ceased growth and exhibited extreme filamentous morphology; by 5 h there was partial recovery with restoration of relatively normal cell morphology. In contrast, preadapted cells were less drastically affected in their morphology and growth. Cellular oxidative stress, as monitored by use of an H 2 O 2 -responsive fluorescent dye, was most severe in the nonadapted cells at 3 h postinoculation, lower in the partially recovered cells at 5 h postinoculation, and lower still in the preadapted cells. Chromate exposure depleted cellular levels of reduced glutathione and other free thiols to a greater extent in nonadapted than preadapted cells. In both cell types, the SOS response was activated, and levels of proteins such as SodB and CysK, which can counter oxidative stress, were increased. Some mutants missing antioxidant proteins (SodB, CysK, YieF, or KatE) were more sensitive to chromate. Thus, oxidative stress plays a major role in chromate toxicity in vivo, and cellular defense against this toxicity involves activation of antioxidant mechanisms. As bacterial chromate bioremediation is limited by the toxicity of chromate, minimizing oxidative stress during bacterial chromate reduction and bolstering the capacity of these organisms to deal with this stress will improve their effectiveness in chromate bioremediation.Chromate [Cr(VI)] is a widespread environmental pollutant, as it is a by-product of numerous industrial processes and nuclear weapons production (5). Because chromate is soluble, environmental contamination is difficult to contain. This solubility also promotes the active transport of chromate across biological membranes (7), and once internalized by cells, Cr(VI) exhibits a variety of toxic, mutagenic, and carcinogenic effects (34, 44). In contrast, most cells are impermeable to Cr(III), which is insoluble under typical environmental conditions (30); as measured by the Ames test, it is therefore some 1,000-fold less mutagenic than Cr(VI) (19). Thus, strategies for decontamination of environmental chromate focus on reducing it to Cr(III). Chemical methods for this are prohibitively expensive for large-scale environmental application and frequently have damaging consequences of their own (7), and so bacterial bioremediation is of considerable interest as an environmentally friendly and affordable solution to chromate pollution.Several bacteria, including Escherichia coli, Shewanella oneidensis, and numerous species of Pseudomonas and Bacillus, can reduce Cr(VI) to Cr(III) (17, 39); nonetheless, an effective bacterial system for in situ reduction has not yet been developed. One reason is that chromate is also toxic to the remediating bacteria (17). Our in vitro studies have strongly i...

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Effect of Chromate Stress on Escherichia coli K-12

et al. 2006

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“…Chromates are mutagenic in Escherichia coli and in Salmonella typhimurium (60)(61)(62)(63)(64)(65)(66)(67)(68)(69)(70)(71)(72) and influence DNA repair in Bacillus subtilis (69,73). Venitt and Levi (60) and Petrilli and de Flora (62) in a comparative study found no significant differences in dose-response between the soluble and slightly soluble compounds in either the Salmonella or the Coil system.…”

Section: Epidemiological Studiesmentioning

confidence: 99%

The Carcinogenicity of Chromium

Norseth¹

1981

Environmental Health Perspectives

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“…However, later studies by several groups, including that of Ames, have been successful in determining metal mutagenesis using this in vitro assay. Lofroth and Ames (29) reported that chromate and dichromate induced frameshift mutations in three different strains of S. typhimurium. Further studies by Petrilli and de Flora (30) confirmed that hexavalent chromium compounds (sodium dichromate, chromic acid and calcium chromate) produced significant increases in histidine reversion using four tester strains.…”

Section: Effects Of Metals In Bacterial Bioassaysmentioning

confidence: 99%

Effects of metals in in vitro bioassays.

Sirover¹

1981

Environ Health Perspect

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The capacity of in vitro bioassays to detect the potential carcinogenicity of metal compounds is reviewed. The in vitro bioassays discussed include: bacterial reversion analysis to determine the capacity of metal salts to revert SalmoneUa typhimurium histidine auxotrophs or to revert Escherichia coli WP 2 tryp-to tryptophan prototrophy; examination of the ability of metal salts to preferentially inhibit cell growth in Bacillus subtilis cells deficient in DNA repair pathways; determination of the ability of metal salts to induce resistance to base analogs in mammalian cells; the capacity of metal salts to enhance viral transformation of mammalian cells or to transform cells in the absence of virus; and the ability of metal salts to induce chromosomal aberrations in mammalian cells. Using each of these in vitro bioassays, diverse metal compounds have been identified as potential carcinogens. Furthermore, the use of different compounds of a specific metal may allow a determination of the valence which may be required for carcinogenesis.

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Mutagenicity of inorganic compounds in Salmonella typhimurium: arsenic, chromium and selenium

Cited by 68 publications

References 0 publications

Effect of Chromate Stress on Escherichia coli K-12

Effect of Chromate Stress on Escherichia coli K-12

The Carcinogenicity of Chromium

Effects of metals in in vitro bioassays.

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