Project description:The weathering of volcanic minerals makes a significant contribution to the global silicate weathering budget, influencing carbon dioxide drawdown and climate control. Basalt rocks may account for over 30% of the global carbon dioxide drawdown in silicate weathering. Yet the genetics of biological rock weathering are unknown. For the first time, we apply a DNA microarray to investigate the genes involved in weathering by the heavy metal resistant organism, Cupriavidus metallidurans CH34; in particular we investigate the sequestering of iron. The results show that the bacterium sequesters iron in the ferrous state (FeII); therefore, not requiring siderophores. Instead an energy efficient process involving upregulation of large porins is employed concomitantly with genes associated with biofilm formation. We hypothesise that rock weathering is induced by changes in chemical equilibrium at the microbe-mineral interface, reducing the saturation state of iron. We also demonstrate that low concentrations of metals in the basalt induce heavy metal resistant genes. Volcanic environments are analogous to some of the earliest environments on Earth. These results not only elucidate the mechanisms by which microorganisms might have sequestered nutrients on the early Earth but they also provide an explanation for the evolution of multiple heavy metal resistance genes long before the creation of contaminated industrial biotopes by human activity. Cultures of Cupriavidus metallidurans CH34 were grown in Tris buffered medium MM284 media (with iron), MM284 without iron and MM284 without iron with sterilized basalt at 25 rpm, 30°C until mid-log phase. RNA was extracted from the cells. Three biological replicates of both samples were differentially labeled (resp. Cy3 and Cy5) and hybridized to three CH34 60-mer oligonucleotide glass-spotted microarray carrying three technical repeats.
Project description:Response of Cupriavidus metallidurans CH34 to cisplatin, Pt(IV)chloride and Au-NP In this study 7 different treatments were performed (first 2 as 3 replicates) to acquire expression profiles of the total genome of Cupriavidus metallidurans
Project description:Response of Cupriavidus metallidurans CH34 to NaAuCl4, Au(I)-thiomalate, Au(I)-thiosulfate, KAuCN, (KCN as control) In this study 10 different treatments were performed (first 7 as 3 replicates) to acquire expression profiles of the total genome of Cupriavidus metallidurans
Project description:Proteomic response of Cupriavidus metallidurans CH34 to gold stress as in comparison to copper stress and control. Please note that 25Au in gel file names is a typo and should read 50Au.
Project description:Cupriavidus metallidurans CH34 is a metal resistant beta-proteobacterium. The genome of this bacterium contain many genes involved in heavy metal resistance. Gene expression of C. metallidurans was studied after the addition of of Zn(II), Cd(II), Cu(II), Ni(II), Pb(II), Hg(II) or Co(II). Keywords: Heavy metal stress response
