Mutagenesis metal compounds

Rossman TG, Molina M. 1986. The genetic toxicology of metal compounds II. Enchancement of ultraviolet light-induced mutagenesis in Escherichia coli WP2. Environ Mutagen 8 263-271. 

Hsie, A.W., Johnson, N.P., Couch, B., Sebastian, J.R.S., O Meill, J.P., Hoeschele, J.D., Rahn, R.O., and Forbes, N.L., Quantitative mammalian cell mutagenesis and a preliminary study of mutagenic potential of metallic compounds, in Trace Metals in Health and Disease, Kharasch, N., Ed., Raven Press, New York, NY, 1979, pp. 55-69. 

Studies on mutagenesis by metal compounds may be complicated by inducible tolerance mechanisms in some cells. Metallothioneins (MT) are small cysteine-rich proteins which bind a number of metals with high affinity. The reader is referred to Chap. 5 in this volume for more detail. Besides cadmium, zinc, and copper salts, a number of other metal salts have also been shown to induce MT synthesis and/or to bind to the MT protein. Hg(II), Co(II), and Ni(II), but not Pb(II), induce MT synthesis in primary cultures of rat hepatocytes (Bracken and Klaassen 1987), and may do so in the cultured cells used for mammalian mutagenesis experiments. Thus, under some experimental protocols, the metal salt being assayed may itself induce metallothionein, or the results of mutagenicity assays may be confounded by components of the medium or serum which affect the levels of metallothionein in the cell (Rossman and Goncharova, unpublished). 

Cerutti PH (1985) Pro-oxidant states and tumor promotion. Science 227 375-381 Chiocca SM, Sterner DA, Biggart NW, Murphy EC (1991) Nickel mutagenesis alteration of the MiSV40110 thermosensitive splicing phenotype by a nickel-induced duplication of the 3 splice-site. Mol Carcinog 4 61-71 Christie NT, Costa M (1983) In vitro assessment of the toxicity of metal compounds. 

Rossman TG (1989) On the mechanism of the comutagenic effect of Cu(II) with ultraviolet light. Biol Trace Elem Res 21 383-388 Rossman TG, Molina M (1986) The genetic toxicology of metal compounds. II. Enhancement of ultraviolet light-induced mutagenesis in E. coli WP2. Environ Mutagen 8 263-271... 

The dependence of the activity of calcineurin on the redox state of the metal center highlights its importance for catalysis and provides clues to its function in that process. Site-directed mutagenesis studies of PPl, calcineurin, and bacteriophage X protein phosphatase have also provided insights regarding the roles of non-ligand active site residues. Furthermore, the contributions afforded by studies of synthetic model compounds which mimic features of metallophosphatase active sites provide important clues to possible catalytic mechanisms. Indeed many of these models exhibit impressive rate enhancements for phosphate and phosphonate ester hydrolysis [54-62]. In this section we discuss current models regarding the mechanism of phosphate ester hydrolysis by calcineurin and other metallophosphatases in consideration of these studies. 

A book dealing with alkaloids in foods contains an account on caffeine and related compounds. The synthesis of caffeine, the conversion of uric acid into xanthine, and various syntheses of related heterocyclic compounds form subject matters in a review of broad scope. The role of purine alkaloids in trace-metal metabolism, disease resistance, mutagenesis, and chemotaxonomic considerations in plants has been reviewed. 

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