Search

The microbial community in soil samples from two long-term contaminated sites was characterized by using culture-dependent and culture-independent methods. The two sites investigated contained high amounts of heavy metals and were located in the upper Silesia Industrial Region in southern Poland. The evaluation of the aerobic soil microbial population clearly demonstrated the presence of considerable numbers of viable, culturable bacteria at both sites. A high fraction of the bacterial population was able to grow in the presence of high amounts of metals, i.e. up to 10 mM Zn²(+), 3 mM Pb²(+) or 1 mM Cu²(+). Site 1 contained significantly (P0.05) lower bacterial numbers growing in the presence of 10 mM Zn²(+) than site 2, while the opposite was observed for bacteria tolerating 1 mM Cu²(+). This coincided with the contents of these two metals at the two sites. Ecophysiological (EP) indices for copiotrophs (r-strategists) and oligotrophs (K-strategists) pointed to high bacterial diversity at both sites. Fluorescence in situ hybridization (FISH) analysis indicated that Actinobacteria and Proteobacteria represent the physiologically active fraction of bacteria at the two sites. Shannon diversity (H') indices for FISH-detected bacterial phylogenetic groups were not significantly different at the two sites.

There is a proven potential of femtosecond lasers for medical applications like cornea shaping [1] , ear surgery or dental surgery [2] . Minimal invasive treatment of carious tissue has become an increasingly important aspect in modern dentistry. State of the art methods like grinding using turbine-driven drills or ablation by Er:YAG lasers [3] generate mechanical and thermal stress, thus generating micro cracks of several tens of microns in the enamel [4] . These cracks are starting points for new carious attacks and have to be avoided for long term success of the dental treatment. By using femtosecond lasers (1 fs =10 −15 s ) for ablating dental tissue, these drawbacks can be overcome. We have demonstrated that femtosecond laser ablation offers a tool for crack-free generation of cavities in dental tissue. Furthermore, spectral analysis of the laser induced plasma has been used to indicate carious oral tissue. Our latest results on femtosecond laser dentistry will be presented, demonstrating the great potential of this kind of laser technology in medicine.