Project description:We investigated the toxicity of soil samples derived from a former municipal landfill site in the South of the Netherlands, where a bioremediation project is running aiming at reusing the site for recreation. Both an organic soil extract and the original soil sample was investigated using the ISO standardised Folsomia soil ecotoxicological testing and gene expression analysis. The 28 day survival/reproduction test revealed that the ecologically more relevant original soil sample was more toxic than the organic soil extract. Microarray analysis showed that the more toxic soil samples induced gene regulatory changes in twice as less genes compared to the soil extract. Consequently gene regulatory changes were highly dependent on sample type, and were to a lesser extent caused by exposure level. An important biological process shared among the two sample types was the detoxification pathway for xenobiotics (biotransformation I, II and III) suggesting a link between compound type and observed adverse effects. Finally, we were able to retrieve a selected group of genes that show highly significant dose-dependent gene expression and thus were tightly linked with adverse effects on reproduction. Expression of four cytochrome P450 genes showed highest correlation values with reproduction, and maybe promising genetic markers for soil quality. However, a more elaborate set of environmental soil samples is needed to validate the correlation between gene expression induction and adverse phenotypic effects.
Project description:Indole-3-acetic acid (IAA), knows as common plant hormone, is one of the most distributed indole derivatives in the environment. A novel strain, which was able to use IAA as sole source of carbon and nitrogen, was isolated from farm soil, identified and classified as Pseudomonas composti LY1 based on 16S rRNA sequence and genome analysis. The optimal growth conditions for LY1 with IAA are characterized. Proteome profile of strain LY1 to IAA and citrate were analyzed and compared using label free strategy with LC-MS/MS.
Project description:References:
1. Xiaomei Zhu, Lan Yin, Leroy Hood, David Galas and Ping Ao, Efficiency, Robustness and Stochasticity of Gene Regulatory networks in Systems biology: Lambda switch as a working example, 2006.
2. Adam Arkin, John Ross and Harley H. McAdams, Stochastic kinetic analysis of developmental pathway bifurcation in phage lambda-infected Escherichia coli cells, 1998, Genetics, 149: 1633-1648.
3. GenBank sequence: NC_001416 is the whole genome sequence of phage lambda.
Project description:Here, we investigated the impact of Stx2 phage carriage on Escherichia coli (E. coli) K-12 MG1655 host gene expression. Using quantitative RNA-seq analysis, we compared the transcriptome of naïve MG1655 and the lysogens carrying the Stx2 phage of the 2011 E. coli O104:H4 outbreak strain or of the E. coli O157:H7 strain PA8, which share high degree of sequence similarity.
Project description:Arbuscular mycorrhizal (AM) fungi contribute to plant nutrient uptake in systems managed with reduced fertilizer inputs such as organic agriculture and natural ecosystems by extending the effective size of the rhizosphere and delivering mineral. Connecting the molecular study of the AM symbiosis with agriculturally- and ecologically-relevant field environments remains a challenge and is a largely unexplored research topic. This study utilized a cross-disciplinary approach to examine the transcriptional, metabolic, and physiological responses of tomato (Solanum lycopersicum) AM roots to a localized patch of nitrogen (N). A wild-type mycorrhizal tomato and a closely-related nonmycorrhizal mutant were grown at an organic farm in soil that contained an active AM extraradical hyphal network and soil microbe community. The majority of genes regulated by upon enrichment of nitrogen were similarly expressed in mycorrhizal and nonmycorrhizal roots, suggesting that the primary response to an enriched N patch is mediated by mycorrhiza-independent root processes. However where inorganic N concentrations in the soil were low, differential regulation of key tomato N transport and assimilation genes indicate a transcriptome shift towards mycorrhiza-mediated N uptake over direct root supplied N. Furthermore, two novel mycorrhizal-specific tomato ammonium transporters were also found to be regulated under low N conditions. A conceptual model is presented integrating the transcriptome response to low N and highlighting the mycorrhizal-specific ammonium transporters. These results enhance our understanding of the role of the AM symbiosis in sensing and response to an enriched N patch, and demonstrate that transcriptome analyses of complex plant-microbe-soil interactions provide a global snapshot of biological processes relevant to soil processes in organic agriculture.
Project description:Bacteria belonging to phylum Gemmatimonadetes are found in a wide variety of environments and are particularly abundant in soils. To date, only two Gemmatimonadetes strains have been characterized. Here we report the complete genome sequence and methylation pattern of Gemmatirosa kalamazoonensis KBS708 (ATCC BAA-2150; NCCB 100411), the first characterized Gemmatimondetes strain isolated from soil.