Autometallographical procedure for the localization of metal traces in molluscan tissues by light microscopy

The authors present a relatively simple autometallographical procedure for metal localization in biological tissues. The protocol demonstrates metals present at very low concentrations in certain key tissues of winkles and mussels. The following procedural variables have been considered: the type of fixation, the type of photographic emulsion and its way of application, and the type of photographic developer. In addition, some staining techniques were used to enhance contrast without masking revealed metal deposits by significant background levels. The protocol offers reproducible results and excellent resolution. This technique can be valuable in physiological and toxicological studies on molluscs at the cell and tissue levels.