Yeast cells long-term interaction with asbestos fibers

Saccharomyces cerevisiae was supported on chrysotile, crocidolite and lixiviated chrysotile. Samples of the supported cells and free cells were observed by confocal laser scanning microscopy. After 30 days, the free cells showed no viability when stored at 30 degrees C, and a viability of 40% when stored at 4 degrees C. Supported cells stored at 30 degrees C were more viable than the free cells at early times, but showed no viability after 30 days. Samples stored at 4 degrees C showed that the adhered cells are more viable than the free cells, up to 30 days. Cells supported on chrysotile and lixiviated chrysotile had 80% viability, and on crocidolite 70% viability. Scanning electron microscopy showed that cells supported on lixiviated chrysotile are fully covered by the support, but crocidolite fibers adhere less, since they are stiffer. Fermentation experiments performed after 3 years storage showed that four from the five lixiviated chrysotile samples and one of the three crocidolite samples were active. In all cases, a delay time for the onset of fermentation was observed indicating a state of latency.