Ontology highlight
ABSTRACT:
PROVIDER: PRJNA1229074 | ENA |
REPOSITORIES: ENA
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Project description:The effects of ocean acidification (OA) on nitrous oxide (N2O) production and on the community composition of ammonium oxidising archaea (AOA) were examined in the northern and southern sub-polar and polar Atlantic Ocean. Two research cruises were performed during June 2012 between the North Sea and Arctic Greenland and Barent Seas, and in January-February 2013 to the Antarctic Scotia Sea. Seven stations were occupied in all during which shipboard experimental manipulations of the carbonate chemistry were performed through additions of NaHCO3- + HCl in order to examine the impact of short- term (48 hour for N2O and between 96 and 168 hour for AOA) exposure to control and elevated conditions of OA. During each experiment, triplicate incubations were performed at ambient conditions and at 3 lowered levels of pH which varied between 0.06 and 0.4 units according to the total scale and which were targeted at CO2 partial pressures of ~500, 750 and 1000 μatm. The AOA assemblage in both Arctic and Antarctic regions was dominated by two major archetypes that represent the marine AOA clades most often detected in seawater. There were no significant changes in AOA assemblage composition between the beginning and end of the incubation experiments. N2O production was sensitive to decreasing pHT at all stations and decreased by between 2.4 and 44% with reduced pHT values of between 0.06 and 0.4. The reduction in N2O yield from nitrification was directly related to a decrease of between 28 and 67% in available NH3 as a result of the pH driven shift in the NH3:NH4+ equilibrium. The maximum reduction in N2O production at conditions projected for the end of the 21st century was estimated to be 0.82 Tg N y-1.
2015-08-15 | GSE72072 | GEO
Project description:Organophosphorous flame retardants (PFRs) were first reported in the late 1970, and today they account for approximately 20 % of the total use of flame retardants in Europe. PFRs are found ubiquitously in the environment, including remote areas stretching from the Arctic to the Antarctic. Generally, similar levels of PFRs is observed between Arctic and more rural areas. The toxicity of PFRs varies depending on their chemical structure. The World Health Organization have reported LC50 values for mammals and aquatic organisms with high variation from 4.2 to 180 mg/L or 707 to 4700 mg/kg body weight, depending on substance and test species. However, little is known about the toxicity and physiological effects of PFRs to fish, particularly in the Arctic species. Hence, the objective of this study is to determine the effects of PFR exposure on hepatic gene expression patterns in Atlantic cod (Gadus morhua) using liver explants in vitro. Liver explants were exposed to 2-Ethylhexyl diphenyl phosphate (EHDPP), tris(2-chloroisopropyl)phosphate (TCPP), and a mixture of both EHDPP and TCPP for 0, 24 and 48 hours. Samples were analyzed for gene expresson profiling using RNAseq. RNAsequening results suggest that exposure to PFRs differentially expressed genes involved in xenobiotic metabolism. We did not observe any chemical-specific effects on gene expression patterns. However, temporal changes in gene expression were observed. Most of the differentially expressed genes (DE) in 24h exposed samples are related in xenobiotic metabolism, whereas in 48h samples DE genes belong to diverse physiological processes.
2017-12-31 | GSE103954 | GEO
Project description:Arctic and Antarctic PHA producing bacteria
| PRJNA991094 | ENA
Project description:Arctic and Antarctic Lakes Raw sequence reads
| PRJNA1000778 | ENA
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:C5aR1, a receptor for the complement activation proinflammatory fragment, C5a, is primarily expressed on cells of the myeloid lineage, and to a lesser extent on endothelial cells and neurons in brain. Previous work demonstrated C5aR1 antagonist, PMX205, decreased amyloid pathology and suppressed cognitive deficits in Alzheimer Disease (AD) mouse models. In the Arctic AD mouse model, genetic deletion of C5aR1 prevented behavior deficits at 10 months. However, the molecular mechanisms of this protection has not been definitively demonstrated. To understand the role of microglial C5aR1 in the Arctic AD mouse model, we have taken advantage of the CX3CR1GFP and CCR2RFP reporter mice to distinguish microglia as GFP-positive and infiltrating monocytes as GFP and RFP positive, for subsequent transcriptome analysis on specifically sorted myeloid populations from wild type and AD mouse models. Immunohistochemical analysis of mice aged to 2, 5, 7 and 10 months showed no change in amyloid beta (Ab) deposition in the Arctic C5aR1 knockout (KO) mice relative to that seen in the Arctic mice. Of importance, no CCR2+ monocytes/macrophages were found near the plaques in the Arctic brain with or without C5aR1. RNA-seq analysis on microglia from these mice identified inflammation related genes as differentially expressed, with increased expression in the Arctic mice relative to wildtype and decreased expression in the Arctic/C5aR1KO relative to Arctic. In addition, phagosomal-lysosomal proteins and protein degradation pathways that were increased in the Arctic mice were further increased in the Arctic/C5aR1KO mice. These data are consistent with a microglial polarization state with restricted induction of inflammatory genes and enhancement of clearance pathways.
2017-10-10 | GSE93824 | GEO
Project description:Using RNAseq of small RNA libraries isolated from the gill tissue of the Antarctic fish Trematomus bernacchii we have characterized the termal sensitivity of miRNA homologues in these highly stenothermic fish.
2019-04-02 | GSE128132 | GEO