Project description:The effects of the aromatic hydrocarbons benzene and toluene on Nitrosomonas europaea, a nitrifying bacterium that plays an important role in the removal of nitrogen from wastewater treatment plants, were studied in batch reactors. Exposure to 20 M toluene and 40 M benzene resulted in a 50% reduction in nitrifying activity after 1 h. However, Affymetrix microarray experiments detected no significant changes in gene expression in toluene exposed cells. Cells exposed to benzene were found to up-regulate a gene cluster (NE 1545 - NE 1551). This gene cluster appears to be involved with fatty-acid metabolism, lipid and membrane protein biosynthesis. TEM experiments reveal that cells exposed to benzene decrease the thickness of their membrane and the membrane becomes more structured. Keywords: stress response, benzene, toluene
2008-02-13 | GSE10507 | GEO
Project description:Thickness determines microbial community structure and function in nitrifying biofilms via deterministic assembly
Project description:The Wood-Ljungdahl pathway in acetogens converts C1 compounds, such as CO2 and CO, into acetyl-CoA. Similarly, the glycine synthase pathway assimilates C1 compounds into glycine. Partial glycine synthase genes are widely conserved in the Wood-Ljungdahl pathway gene cluster but functional relationship between the pathways in autotrophic condition remains unknown. To comprehend, we assembled Clostridium drakei genome (5.7-Mbp) with intact glycine synthase pathway and constructed a genome-scale metabolic model, iSL836, predicting increased metabolic flux rates of the Wood-Ljungdahl pathway and the glycine synthase-reductase associated reactions under autotrophic conditions. Along with the observation of significant transcriptional activation of genes in the pathways, surprisingly, 13C-labeling experiments and enzyme activity assays confirmed the strain synthesizes glycine and converts into acetyl-phosphate. This study suggests the Wood-Ljungdahl and the glycine synthase-reductase pathways convert CO2 into acetyl-CoA and acetyl-phosphate, respectively. In our knowledge, this is the first report on co-utilization of the pathways under autotrophic growth in acetogen.
Project description:we studied the functional composition of a packed-bed nitrifying bioreactor inoculated with a co-culture of Nitrosomonas europaea (ATCC 25978) and Nitrobacter winogradskyi (ATCC 25391) after 840 days of operation.
Project description:rs07-09_bou - catma1-bou - Autotrophic growth acquisition is abolished in the bou mutant in Arabidopsis thaliana. BOU encodes a putative mitochondrial acyl carnitine carrier. bou mutant is blocked at the cotyledon stage. Autotrophic growth of the bou mutant can be achieved with addition of sugar in the medium or in darkness. Moreover, BOU gene expression is activated by light and depends on plant developmental stage. We wish to determine what are the consequences of bou gene mutation at the transcriptome level. We wish to understand whether bou growth arrest is due to the modification of specific genes expression or to a general effect on metabolism at the transition from heterotrophic to autotrophic growth. - Seeds from a heterozygous plants were grown for either 5 or 8 days after germination on synthetic medium (MS/2) without sugar under continuous light. We harvested cotyledon-stage blocked plants (bou phenotype) from three independent Petri dishes and also green seedlings with true leaves and fully developed root (heterozygotes with a wild-type phenotype) . We also grew independently Col-O plants for 5 and 8 days to compare them with the bou mutants. Keywords: gene knock in (transgenic),normal vs disease comparison,time course
Project description:The goal of this experiment was to explore the molecular network of glucose-TOR signaling in Arabidopsis seedling autotrophic transition stage. We used the whole-genome microarrays to detail the global program of gene expression mediated by glucose and TOR.