Project description:Polyhydroxyalkanoates (PHAs) are bio-based, biodegradable polyesters that can be produced from organic-rich waste streams using mixed microbial cultures. To maximize PHA production, mixed microbial cultures may be enriched for PHA-producing bacteria with a high storage capacity through the imposition of cyclic, aerobic feast-famine conditions in a sequencing batch reactor (SBR). Though enrichment SBRs have been extensively investigated a bulk solutions-level, little evidence at the proteome level is available to describe the observed SBR behavior to guide future SBR optimization strategies. As such, the purpose of this investigation was to characterize proteome dynamics of a mixed microbial culture in an SBR operated under aerobic feast-famine conditions using fermented dairy manure as the feedstock for PHA production. At the beginning of the SBR cycle, excess PHA precursors were provided to the mixed microbial culture (i.e., feast), after which followed a long duration devoid of exogenous substrate (i.e., famine). Two-dimensional electrophoresis was used to separate protein mixtures during a complete SBR cycle, and proteins of interest were identified.
Project description:Experimental design: 2 genotypes: PI- (resistant USDA Plant Introduction (PI459025B) line containing SBR Rpp4 resistance gene) & Cultivar Williams that does not have a known SBR resistance gene 2 treatments: Soybean rust (Phakopsora pachyrhizi) isolate Hawaii 94-1 & mock infection 3 replications 6 time points: 12, 24, 72, 144, 216 and 288 hours after inoculation TOTAL: 72 Affymetrix GeneChip(R) Soybean Genome Arrays Mock treatment: 0.01% Tween 20 Hawaii 94-1 treatment: 500,000 spores per ml in 0.01% Tween 20 ****[PLEXdb(http://www.plexdb.org) has submitted this series at GEO on behalf of the original contributor, Steve Whitham. The equivalent experiment is GM37 at PLEXdb.]
Project description:We performed small RNA-seq (sRNA-seq) study of Arabidopsis shoots under iron-sufficient (+Fe), iron deficient (-Fe) and iron resupply (Fe resupply) conditions to investigate and identify sRNAs whose expression is regulated by iron deficiency.
Project description:In this study we developed MPE-seq, a method for the genome-wide characterization of chromatin that involves the digestion of nuclei with methidiumpropyl-EDTA-Fe(II) [MPE-Fe(II)] followed by massively parallel sequencing. Like micrococcal nuclease (MNase), MPE-Fe(II) preferentially cleaves the linker DNA between nucleosomes. We also performed MNase-seq as a comparison. We further performed ChIP-seq using chromatin samples obtained by MPE-Fe(II) or MNase digestion of nuclei.
Project description:The Arabidopsis thaliana Myb transcription factor, FE, acts as a key regulator of phase transition. In order to identify potential target genes of FE protein, we performed microarray experiments. Using fe-1 and transgenic plants overexpressing GR-tagged FE (35S::FE-GR), we compared transcriptional profiling of WT (L.er) vs fe-1 and Dex-treated 35S::FE-GR vs Mock-treated 35S::FE-GR. Transcriptional profiling of A. thaliana comparing WT (L.er) with the fe-1 mutant
Project description:Iron (Fe) and phosphorus (P) are essential nutrients with close geochemical association. They exist at low concentrations in surface waters and may be co-limiting resources for phytoplankton growth. However, the adaptive strategies of photosynthetic organisms to Fe/P co-limitation remain largely unknown. Here, we show that phosphorus deficiency increases the growth of Fe-limited cyanobacteria through a PhoB-mediated regulatory network. In addition to its well-recognized role in controlling phosphate homeostasis, PhoB regulates key metabolic processes crucial for Fe-limited cyanobacteria, including ROS detoxification and Fe uptake. Transcript abundances of PhoB-targeted genes are enriched in samples from the P-deplete ocean, and a conserved PhoB binding site is widely present in the promoters of the targets, suggesting that the strategy we discovered may be highly conserved. Our findings provide important molecular insights into the response of cyanobacteria to simultaneous Fe/P nutrient limitation and help in understanding how nutrient availability affects primary productivity in aquatic environments.