Study on the toxic effect of lead(II) ion on Escherichia coli

The toxic effects of lead(II) have been studied in Escherichia coli cells. Using microcalorimetric analysis, it was shown that E. coli growth was inhibited in the presence of Pb2+ resulting from damage to the cell membrane and that Pb2+ takes part in the metabolism of cells. Treatment with lysozyme confirms damage to the cell's outer membrane. Similarities between the ionic radii and charge/radius ratio cause Pb(II) to replace Ca(II) at the binding sites of lipopolysacharides, leading to rupture of protecting areas on the cell's surface. Consequently, the protection and functionality of outer membrane is lost, thus becoming the basis for the biological effect of Pb2+ on E. coli.