Ontology highlight
ABSTRACT:
PROVIDER: PRJNA1141967 | ENA |
REPOSITORIES: ENA
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Project description:Because of severe abiotic limitations, Antarctic soils represent simplified ecosystems, where microorganisms are the principle drivers of nutrient cycling. This relative simplicity makes these ecosystems particularly vulnerable to perturbations, like global warming, and the Antarctic Peninsula is among the most rapidly warming regions on the planet. However, the consequences of the ongoing warming of Antarctica on microorganisms and the processes they mediate are unknown. Here, using 16S rRNA gene pyrosequencing and qPCR, we report a number of highly consistent changes in microbial community structure and abundance across very disparate sub-Antarctic and Antarctic environments following three years of experimental field warming (+ 0.5-2°C). Specifically, we found significant increases in the abundance of fungi and bacteria and in the Alphaproteobacteria-to-Acidobacteria ratio. These alterations were linked to a significant increase in soil respiration. Furthermore, the shifts toward generalist or opportunistic bacterial communities following warming weakened the linkage between bacterial diversity and functional diversity. Warming also increased the abundance of some organisms related to the N-cycle, detected as an increase in the relative abundance of nitrogenase genes via GeoChip microarray analyses. Our results demonstrate that soil microorganisms across a range of sub-Antarctic and Antarctic environments can respond consistently and rapidly to increasing temperatures, thereby potentially disrupting soil functioning. We conducted in situ warming experiments for three years using open-top chambers (OTCs) at one sub-Antarctic (Falkland Islands, 52ºS) and two Antarctic locations (Signy and Anchorage Islands, 60ºS and 67ºS respectively) (see Supplementary Fig. 1 for a map). OTCs increased annual soil temperature by an average of 0.8°C (at a depth of 5 cm), resulting in 8-43% increase in positive-degree days annually and a decrease in freeze-thaw cycle frequency by an average of 15 cycles per year (8). At each location, we included densely vegetated and bare fell-field soils in the experimental design for a total of six environments. Densely vegetated and bare environments represent two contrasting environments for Antarctic soil microorganisms, with large differences in terms of C and N inputs to soils. Massively parallel pyrosequencing (Roche 454 GS FLX Titanium) of 16S rRNA gene amplicons was used to follow bacterial diversity and community composition [GenBank Accession Numbers: HM641909-HM744649], and functional gene microarrays (GeoChip 2.0)(11) were used to assess changes in functional gene distribution. Bacterial and fungal communities were also quantified using real-time PCR.
2010-12-30 | E-GEOD-22825 | biostudies-arrayexpress
Project description:Because of severe abiotic limitations, Antarctic soils represent simplified ecosystems, where microorganisms are the principle drivers of nutrient cycling. This relative simplicity makes these ecosystems particularly vulnerable to perturbations, like global warming, and the Antarctic Peninsula is among the most rapidly warming regions on the planet. However, the consequences of the ongoing warming of Antarctica on microorganisms and the processes they mediate are unknown. Here, using 16S rRNA gene pyrosequencing and qPCR, we report a number of highly consistent changes in microbial community structure and abundance across very disparate sub-Antarctic and Antarctic environments following three years of experimental field warming (+ 0.5-2°C). Specifically, we found significant increases in the abundance of fungi and bacteria and in the Alphaproteobacteria-to-Acidobacteria ratio. These alterations were linked to a significant increase in soil respiration. Furthermore, the shifts toward generalist or opportunistic bacterial communities following warming weakened the linkage between bacterial diversity and functional diversity. Warming also increased the abundance of some organisms related to the N-cycle, detected as an increase in the relative abundance of nitrogenase genes via GeoChip microarray analyses. Our results demonstrate that soil microorganisms across a range of sub-Antarctic and Antarctic environments can respond consistently and rapidly to increasing temperatures, thereby potentially disrupting soil functioning.
2010-12-30 | GSE22825 | GEO
Project description:Spatial organization of the transcriptome has emerged as a powerful means for regulating the post-transcriptional fate of RNA in eukaryotes; however, whether prokaryotes use RNA spatial organization as a mechanism for post-transcriptional regulation remains unclear. Here we used super-resolution microscopy to image the E. coli transcriptome and observed a genome-wide spatial organization of RNA: mRNAs encoding inner-membrane proteins are enriched at the membrane, whereas mRNAs encoding outer-membrane, cytoplasmic and periplasmic proteins are distributed throughout the cytoplasm. Membrane enrichment is caused by co-translational insertion of signal peptides recognized by the signal-recognition particle. Our time-resolved RNA-sequencing and live-cell super-resolution imaging experiments revealed a physiological consequence of this spatial organization and the underlying mechanism: membrane localization enhances degradation rates of inner-membrane-protein mRNAs by placing them in proximity to membrane-bound RNA degradation enzymes. Together, these results demonstrate that the bacterial transcriptome is spatially organized and that this organization shapes the posttranscriptional Spatial organization of the transcriptome has emerged as a powerful means for regulating the post-transcriptional fate of RNA in eukaryotes; however, whether prokaryotes use RNA spatial organization as a mechanism for post-transcriptional regulation remains unclear. Here we used super-resolution microscopy to image the E. coli transcriptome and observed a genome-wide spatial organization of RNA: mRNAs encoding inner-membrane proteins are enriched at the membrane, whereas mRNAs encoding outer-membrane, cytoplasmic and periplasmic proteins are distributed throughout the cytoplasm. Membrane enrichment is caused by co-translational insertion of signal peptides recognized by the signal-recognition particle. Our time-resolved RNA-sequencing and live-cell super-resolution imaging experiments revealed a physiological consequence of this spatial organization and the underlying mechanism: membrane localization enhances degradation rates of inner-membrane-protein mRNAs by placing them in proximity to membrane-bound RNA degradation enzymes. Together, these results demonstrate that the bacterial transcriptome is spatially organized and that this organization shapes the post-transcriptional dynamics of mRNAs.
2016-06-07 | GSE75818 | GEO
Project description:A huge number of microorganisms are colonized in human gut and the balance of their composition is closely related to human health. Recently, many probiotics such as bifidobacteria or lactobacilli have been introduced in our life as effective agents. However, we have not well understood their beneficial mechanisms including host-bacterial crosstalk To analyze the differences of gene expression between BA- or BL-associated murine colonic epithelium, we performed comparative transcriptomic analysis.
2011-01-27 | GSE12997 | GEO
Project description:A huge number of microorganisms are colonized in human gut and the balance of their composition is closely related to human health. Recently, many probiotics such as bifidobacteria or lactobacilli have been introduced in our life as effective agents. However, we have not well understood their beneficial mechanisms including host-bacterial crosstalk. Accordingly, we took advantage of the protective mechanisms of probiotics against lethal infection of enterohemorrhagic Escherichia coli O157:H7 in murine gnotobiote model system
2011-01-27 | GSE12998 | GEO
Project description:The human gut is colonized by trillions of microorganisms that influence human health and disease through the metabolism of xenobiotics, including therapeutic drugs and antibiotics. The diversity and metabolic potential of the human gut microbiome have been extensively characterized, but it remains unclear which microorganisms are active and which perturbations can influence this activity. Here, we use flow cytometry, 16S rRNA gene sequencing, and metatranscriptomics to demonstrate that the human gut contains distinctive subsets of active and damaged microorganisms, primarily composed of Firmicutes, which display marked temporal variation. Short-term exposure to a panel of xenobiotics resulted in significant changes in the physiology and gene expression of this active microbiome. Xenobiotic-responsive genes were found across multiple bacterial phyla, encoding novel candidate proteins for antibiotic resistance, drug metabolism, and stress response. These results demonstrate the power of moving beyond DNA-based measurements of microbial communities to better understand their physiology and metabolism. RNA-Seq analysis of the human gut microbiome during exposure to antibiotics and therapeutic drugs.
2012-10-30 | E-GEOD-38151 | biostudies-arrayexpress
Project description:A huge number of microorganisms are colonized in human gut and the balance of their composition is closely related to human health. Recently, many probiotics such as bifidobacteria or lactobacilli have been introduced in our life as effective agents. However, we have not well understood their beneficial mechanisms including host-bacterial crosstalk To analyze the differences of gene expression between BA- or BL-associated murine colonic epithelium, we performed comparative transcriptomic analysis. Bifidobacterium adolescentis (BA)-associated mice and Bifidobacterium longum (BL)-associated mice were used. Colonic epithelium was isolated and gene expression profile was analyzed. Each 3 samples were analyzed.
2011-01-27 | E-GEOD-12997 | biostudies-arrayexpress