| Autor: |
Harpke M; Institute of Microbiology, Friedrich Schiller University Jena, Neugasse 25, D-07743 Jena, Germany., Pietschmann S; Institute of Microbiology, Friedrich Schiller University Jena, Neugasse 25, D-07743 Jena, Germany., Costa FS; Institute of Microbiology, Friedrich Schiller University Jena, Neugasse 25, D-07743 Jena, Germany., Gansert C; Institute of Microbiology, Friedrich Schiller University Jena, Neugasse 25, D-07743 Jena, Germany., Langenhorst F; Institute of Geosciences, Friedrich Schiller University Jena, Carl-Zeiss-Promenade 10, D-07745 Jena, Germany., Kothe E; Institute of Microbiology, Friedrich Schiller University Jena, Neugasse 25, D-07743 Jena, Germany. |
| Abstrakt: |
The adaptation to adverse environmental conditions can lead to adapted microbial communities that may be screened for mechanisms involved in halophily and, in this case, metal tolerance. At a former uranium mining and milling site in Seelingstädt, Germany, microbial communities from surface waters and sediment soils were screened for isolates surviving high salt and metal concentrations. The high salt contents consisted mainly of chloride and sulfate, both in soil and riverbed sediment samples, accompanied by high metal loads with presence of cesium and strontium. The community structure was dominated by Chloroflexi, Proteobacteria and Acidobacteriota, while only at the highest contaminations did Firmicutes and Desulfobacterota reach appreciable percentages in the DNA-based community analysis. The extreme conditions providing high stress were mirrored by low numbers of cultivable strains. Thirty-four extremely halotolerant bacteria (23 Bacillus sp. and another 4 Bacillales, 5 Actinobacteria, and 1 Gamma-Proteobacterium) surviving 25 to 100 mM SrCl 2 , CsCl, and Cs 2 SO 4 were further analyzed. Mineral formation of strontium- or cesium-struvite could be observed, reducing bioavailability and thereby constituting the dominant metal and salt resistance strategy in this environment. |
