Salt and Metal Tolerance Involves Formation of Guttation Droplets in Species of the Aspergillus versicolor Complex.

Three strains of the Aspergillus versicolor complex were isolated from a salty marsh at a former uranium mining site in Thuringia, Germany. The strains from a metal-rich environment were not only highly salt tolerant (up to 20% NaCl), but at the same time could sustain elevated Cs and Sr (both up to 100 mM) concentrations as well as other (heavy) metals present in the environment. During growth experiments when screening for differential cell morphology, the occurrence of guttation droplets was observed, specifically when elevated Sr concentrations of 25 mM were present in the media. To analyze the potential of metal tolerance being promoted by these excretions, proteomics and metabolomics of guttation droplets were performed. Indeed, proteins involved in up-regulated metabolic activities as well as in stress responses were identified. The metabolome verified the presence of amino sugars, glucose homeostasis-regulating substances, abscisic acid and bioactive alkaloids, flavones and quinones.

Chemical data on environmental matrices from an abandoned mining site.

This article contains analytical data on chemical composition of waters and solid samples (mining wastes and biominerals) collected in an abandoned mining area, and they are related with the research article "Geochemistry of rare earth elements in water and solid materials at abandoned mines in SW Sardinia (Italy)" (Medas et al., 2013). Specifically, we present physicochemical data (temperature, electrical conductivity, pH, and redox potential), major components and the main contaminants (Zn, Mn, Cd, Ni, Cu, Pb) detected in stream waters and drainages from mine wastes. Waters were monitored from 2009 to 2011 during different seasonal conditions to give an insight into metal dispersion under different hydrological conditions.