Metal-microbe interactions: contemporary approaches.

Publisher Summary This chapter discusses the methods to study interactions between metals and microorganisms, and demonstrate the necessity of adopting a multidisciplinary approach to tackle this increasingly important and diverse area of microbiology. The multidisciplinary approach surveyed in the chapter involves microbiology, particularly microbial physiology, genetics and molecular biology, bioinorganic chemistry, analytical chemistry, and the application of instrumental techniques. Commonly used methods for the determination of metal concentrations in cells (and in cell compartments or fractions)—that is, those of atomic spectroscopy are discussed. Radiochemical techniques are of particular value in studying the uptake and localization of metals and sometimes offer the only way of studying variations in concentrations of metals in cellular compartments. The use of spectroscopic methods provides information about the ligands, geometries, andthe electronic status of metals coordinated at binding sites, sometimes in living cells. The use of non-invasive techniques is of significant mechanistic potential as they may allow the direct study of ionic and metabolic processes in essentially unperturbed cells. Genetics and molecular biology hold great promise for advancing studies of metal-microbe interactions, particularly those aspects that are currently perceived as especially significant. These include gene regulation by metals (metalcontaining transcription factors and zinc fingers), control of specificity at metalbinding sites and genetic modification of microorganisms for application in biohydrometallurgy. Studies on extracellular precipitates produced by microbial activity or on the complexation of metal ions in supernatant solutions or growth media by release of extracellular ligands are also discussed.