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- Horellou, Cathy, 1967, et al.
(författare)
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The XXL Survey: XXXIV. Double Irony in XXL-North: A tale of two radio galaxies in a supercluster at z = 0.14
- 2018
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Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 620
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Tidskriftsartikel (refereegranskat)abstract
- Aims. We show how the XXL multiwavelength survey can be used to shed light on radio galaxies and their environment. Methods. Two prominent radio galaxies were identified in a visual examination of the mosaic of XXL-North obtained with the Giant Metrewave Radio Telescope at 610 MHz. Counterparts were searched for in other bands. Spectroscopic redshifts from the GAMA database were used to identify clusters and/or groups of galaxies, estimate their masses with the caustic method, and quantify anisotropies in the surrounding galaxy distribution via a Fourier analysis. Results. Both radio galaxies are of FR I type and are hosted by early-type galaxies at a redshift of 0.138. The first radio source, named the Exemplar, has a physical extent of ∼400 kpc; it is located in the cluster XLSSC 112, which has a temperature of ∼2 keV, a total mass of ∼1014 Mo, and resides in an XXL supercluster with eight known members. The second source, named the Double Irony, is a giant radio galaxy with a total length of about 1.1 Mpc. Its core coincides with a cataloged point-like X-ray source, but no extended X-ray emission from a surrounding galaxy cluster was detected. However, from the optical data we determined that the host is the brightest galaxy in a group that is younger, less virialized, and less massive than the Exemplar's cluster. A friends-of-friends analysis showed that the Double Irony's group is a member of the same supercluster as the Exemplar. There are indications that the jets and plumes of the Double Irony have been deflected by gas associated with the surrounding galaxy distribution. Another overdensity of galaxies (the tenth) containing a radio galaxy was found to be associated with the supercluster. Conclusions. Radio Galaxies can be used to find galaxy clusters/groups that are below the current sensitivity of X-ray surveys.
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- Nylen, C, et al.
(författare)
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IL6 and LIF mRNA expression in skeletal muscle is regulated by AMPK and the transcription factors NFYC, ZBTB14, and SP1
- 2018
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Ingår i: American journal of physiology. Endocrinology and metabolism. - : American Physiological Society. - 1522-1555 .- 0193-1849. ; 315:5, s. E995-E1004
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Tidskriftsartikel (refereegranskat)abstract
- Adenosine monophosphate-activated protein kinase (AMPK) controls glucose and lipid metabolism and modulates inflammatory responses to maintain metabolic and inflammatory homeostasis during low cellular energy levels. The AMPK activator 5-aminoimidazole-4-carboxamide-1-β-4-ribofuranoside (AICAR) interferes with inflammatory pathways in skeletal muscle, but the mechanisms are undefined. We hypothesized that AMPK activation reduces cytokine mRNA levels by blocking transcription through one or several transcription factors. Three skeletal muscle models were used to study AMPK effects on cytokine mRNA: human skeletal muscle strips obtained from healthy men incubated in vitro, primary human muscle cells, and rat L6 cells. In all three skeletal muscle systems, AICAR acutely reduced cytokine mRNA levels. In L6 myotubes treated with the transcriptional blocker actinomycin D, AICAR addition did not further reduce Il6 or leukemia inhibitory factor ( Lif) mRNA, suggesting that AICAR modulates cytokine expression through regulating transcription rather than mRNA stability. A cross-species bioinformatic approach identified novel transcription factors that may regulate LIF and IL6 mRNA. The involvement of these transcription factors was studied after targeted gene-silencing by siRNA. siRNA silencing of the transcription factors nuclear transcription factor Y subunit c ( Nfyc), specificity protein 1 ( Sp1), and zinc finger and BTB domain containing 14 ( Zbtb14), or AMPK α1/α2 subunits, increased constitutive levels of Il6 and Lif. Our results identify novel candidates in the regulation of skeletal muscle cytokine expression and identify AMPK, Nfyc, Sp1, and Zbtb14 as novel regulators of immunometabolic signals from skeletal muscle.
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