Project description:Methanotrophs, which help regulate atmospheric levels of methane, are active in diverse natural and man-made environments. This range of habitats and the feast-famine cycles seen by many environmental methanotrophs suggest that methanotrophs dynamically mediate rates of methane oxidation. Global methane budgets require ways to account for this variability in time and space. Functional gene biomarker transcripts are increasingly being studied to inform the dynamics of diverse biogeochemical cycles. Previously, per-cell transcript levels of the methane oxidation biomarker, pmoA, were found to vary quantitatively with respect to methane oxidation rates in model aerobic methanotroph, Methylosinus trichosporium OB3b. In the present study, these trends were explored for two additional aerobic methanotroph pure cultures, Methylocystis parvus OBBP and Methylomicrobium album BG8. At steady-state conditions, per cell pmoA mRNA transcript levels strongly correlated with per cell methane oxidation across the three methanotrophs across many orders of magnitude of activity (R2 = 0.91). Additionally, genome-wide expression data (RNA-seq) were used to explore transcriptomic responses of steady state M. album BG8 cultures to short-term CH4 and O2 limitation. These limitations induced regulation of genes involved in central carbon metabolism (including carbon storage), cell motility, and stress response.
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:We report on genome-wide DNA methylation differences associated with early gestational famine exposure. We find that open chromatin regions and enhancers are especially sensitive to prenatal famine exposure. We compared 24 individuals conceived during the Dutch Famine, a brief 6 month famine at the end of WWII, with a same sex sibling.
Project description:In nature, animals often face feast or famine conditions. We aimed to identify the miRNAs of Caenorhabditis elegans that changed their expression under starvation conditions in stage L4 larvae. Our results highlight 14 miRNAs that show differential expression in starved versus well-fed larvae. In particular, miRNAs of the miR-35-3p/miR-41-3p family were upregulated 6-20 fold upon starvation. We verified the upregulation of miR-35-3p with qPCR. Additionally, we showed that the expression of gld-1, important in ovogenesis, and a validated target of miR-35-3p, was downregulated when the expression of miR-35-3p was higher. This study represents a starting point for a more comprehensive understanding of the role of miRNAs during starvation in C. elegans.
2016-01-27 | GSE67711 | GEO
Project description:Effects of feast-famine nutrient regimes on wastewater algal biofuel communities
Project description:In nature, animals often face feast or famine conditions. We aimed to identify the miRNAs of Caenorhabditis elegans that changed their expression under starvation conditions in stage L4 larvae. Our results highlight 14 miRNAs that show differential expression in starved versus well-fed larvae. In particular, miRNAs of the miR-35-3p/miR-41-3p family were upregulated 6-20 fold upon starvation. We verified the upregulation of miR-35-3p with qPCR. Additionally, we showed that the expression of gld-1, important in ovogenesis, and a validated target of miR-35-3p, was downregulated when the expression of miR-35-3p was higher. This study represents a starting point for a more comprehensive understanding of the role of miRNAs during starvation in C. elegans. Illumina small RNA sequencing of starved and well-fed L4 worms.