Heavy Metal-Resistant Streptomycetes in Soil
Streptomycetes are a dominant group of soil bacteria which belong to the group of Actinobacteria. They are known for their complex life cycle, including mycelial growth and spore production, as well as their production of secondary metabolites, among them a large number of antibiotics. Streptomycetes possess a wide variety of resistance mechanism like biosorption, reduction, biomineralization, extracellular binding by chelators, efflux by transport systems, and intracellular binding of metals. In comparison to pristine soils, heavy metal-contaminated soils show much higher numbers of gram-positive bacteria, with bacilli and streptomycetes dominating over gram-negative proteobateria or firmicutes. The understanding of molecular mechanisms of heavy metal resistance in laboratory cultures as well as directly in soil systems is an essential basis for applied and interdisciplinary research as well as remediation of contaminated sites.
KeywordsAcidic Mine Drainage Heavy Metal Stress Acidithiobacillus Ferrooxidans Heavy Metal Resistance Cladosporium Cladosporioides
We would like to thank the Helmholtz Interdisciplinary Graduate School for Environmental Research (HIGRADE) for scholarship funding, André Schmidt, René Phieler, Michael Klose and Jens Schumacher for their help and support, Sandor Nietzsche for scanning electron microscopy, as well as Dirk Merten for sequential extraction and metal analyses. Petra Mitscherlich is thanked for technical assistance and DFG-GRK1257 and JSMC for support.
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