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Lead Salts (lead + salt)
Selected AbstractsGenotoxicity of inorganic lead salts and disturbance of microtubule functionENVIRONMENTAL AND MOLECULAR MUTAGENESIS, Issue 4 2005Daniela Bonacker Abstract Lead compounds are known genotoxicants, principally affecting the integrity of chromosomes. Lead chloride and lead acetate induced concentration-dependent increases in micronucleus frequency in V79 cells, starting at 1.1 ,M lead chloride and 0.05 ,M lead acetate. The difference between the lead salts, which was expected based on their relative abilities to form complex acetato-cations, was confirmed in an independent experiment. CREST analyses of the micronuclei verified that lead chloride and acetate were predominantly aneugenic (CREST-positive response), which was consistent with the morphology of the micronuclei (larger micronuclei, compared with micronuclei induced by a clastogenic mechanism). The effects of high concentrations of lead salts on the microtubule network of V79 cells were also examined using immunofluorescence staining. The dose effects of these responses were consistent with the cytotoxicity of lead(II), as visualized in the neutral-red uptake assay. In a cell-free system, 20,60 ,M lead salts inhibited tubulin assembly dose-dependently. The no-observed-effect concentration of lead(II) in this assay was 10 ,M. This inhibitory effect was interpreted as a shift of the assembly/disassembly steady-state toward disassembly, e.g., by reducing the concentration of assembly-competent tubulin dimers. The effects of lead salts on microtubule-associated motor-protein functions were studied using a kinesin-gliding assay that mimics intracellular transport processes in vitro by quantifying the movement of paclitaxel-stabilized microtubules across a kinesin-coated glass surface. There was a dose-dependent effect of lead nitrate on microtubule motility. Lead nitrate affected the gliding velocities of microtubules starting at concentrations above 10 ,M and reached half-maximal inhibition of motility at about 50 ,M. The processes reported here point to relevant interactions of lead with tubulin and kinesin at low dose levels. Environ. Mol. Mutagen., 2005. © 2005 Wiley-Liss, Inc. [source] Biological Conversion of Anglesite (PbSO4) and Lead Waste from Spent Car Batteries to Galena (PbS)BIOTECHNOLOGY PROGRESS, Issue 4 2002Jan Weijma Lead paste, a solid mixture containing PbSO4, PbO2, PbO/Pb(OH)2precipitate, and elemental Pb, is one of the main waste fractions from spent car batteries. Biological sulfidation represents a new process for recovery of lead from this waste. In this process the lead salts in lead paste are converted to galena (PbS) by sulfate-reducing bacteria. This paper investigates a continuous process for sulfidation of anglesite (PbSO4), the main constituent of lead paste, and lead paste, consisting of a laboratory-scale gas-lift bioreactor to which a slurry of anglesite or lead paste was supplied. Sulfate or elemental sulfur was added as an additional sulfur source. Hydrogen gas served as an electron donor for the biological reduction of sulfate and elemental sulfur to sulfide by sulfate- and sulfur-reducing bacteria. Anglesite was almost completely converted to galena at a loading rate of 19 kg of PbSO4m,3day,1, producing a sludge of which the crystalline lead phases consisted of >98% PbS (galena) and 1,2% elemental Pb. With lead paste, stable sulfidation rates of up to 17 kg of lead paste m,3day,1were demonstrated, producing a sludge of which the crystalline lead phases consisted of an estimated >96% PbS, 1,2% elemental Pb, and 1,2% PbO2. [source] | ||||||||||