Project description:Archaea, together with Bacteria, represent the two main divisions of life on Earth, with many of the defining characteristics of the more complex eukaryotes tracing their origin to evolutionary innovations first made in their archaeal ancestors. One of the most notable such features is nucleosomal chromatin, although archaeal histones and chromatin differ significantly from those of eukaryotes. Despite increased interest in archaeal histones in recent years, the properties of archaeal chromatin have been little studied using genomic tools. Here, we adapt the ATAC-seq assay to the archaeal context and use it to map the accessible landscape of the genome of the euryarchaeote Haloferax volcanii. We integrate the resulting datasets with genome-wide maps of active transcription and single-stranded DNA (ssDNA), and find that while H. volcanii promoters exist in a preferentially accessible state, modulation of transcriptional activity is not associated with changes in promoter accessibility, unlike the typical situation in eukaryotes. Applying orthogonal single-molecule footprinting methods, we quantify the absolute levels of physical protection of H. volcanii, and find that archaeal nucleosomal chromatin is at its baseline comparably to slightly more open than that of eukaryotes. We also evaluate the degree of coordination of transcription within archaeal operons and make the unexpected observation that some CRISPR arrays are associated with highly prevalent ssDNA structures. These results provide a foundation for the future functional studies of archaeal chromatin.
2022-10-01 | GSE207470 | GEO
Project description:Archaeal community in two soil profiles from Beijing
| PRJNA649147 | ENA
Project description:Bacterial and archaeal communities in water columns of two boreal O2-stratified lakes
Project description:Consumer-resource interactions are a central issue in evolutionary and community ecology because they play important roles in selection and population regulation. Most consumers encounter resource variation at multiple scales, and respond through phenotypic plasticity in the short term or evolutionary divergence in the long term. The key traits for these responses may influence resource acquisition, assimilation and/or allocation. To identify candidate genes, we experimentally assayed genome-wide gene expression in pond and lake Daphnia ecotypes exposed to alternate resource environments. One was a simple, high-quality laboratory diet, Ankistrodesmus falcatus. The other was the complex natural seston from a large lake. In temporary ponds, Daphnia generally experience high-quality, abundant resources, whereas lakes provide low-quality, seasonally shifting resources that are chronically limiting. For both ecotypes, we used replicate clones drawn from a number of separate populations. We compared gene expression in whole Daphnia pulex that had been raised in the lab for 10 days, and then exposed to alternate resource environments for 24 hours. One resource environment was a 24 hour continuation of the lab resource, a satiating level of Ankistrodesmus falcatus. The alternate environment was the natural seston present in the epilimnion of Lake Murray, South Carolina. Two ecotypes were analyzed, one adapted to large lakes, and one adapted to temporary ponds. For each ecotype, eight replicate clones were used. Clones of the lake ecotype were isolated from eight independent lakes, clones of the pond ecotype were isolated from six different ponds. The total number of arrays is 16 (8 replicate clones x 2 ecotypes) x 2 resource environments). Total RNA was extracted from eight whole organisms pooled together. Pools were then converted to cDNA and labelled with a single round of amplification. For array hybridizations, samples from the two resource environments were paired for each clone, and dyes were swapped across clones.
Project description:Archaea are ubiquitous prokaryotes with a wide range of habitats, important roles in ecology, biotechnology and potentially even human health. Despite that, our understanding of archaeal cell biology is still rather limited, partially because the application of systems biology approaches is lacking behind the other domains of life. Here we introduce/announce the Archaeal Proteome Project (ArcPP), a community effort that aims for the comprehensive analysis of archaeal proteomes. Starting with the model archaeon Haloferax volcanii, we have re-analyzed more than 2 TB of MS result files (>20 Mio. spectra) using state-of-the-art bioinformatic tools, increasing peptide spectrum matches and leading to the secure identification of >3000 proteins. This dataset is part of the Archaeal Proteome Project dataset