185 research outputs found
Central administration of melanocortin agonist increased insulin sensitivity in diet-induced obese rats
AbstractIn this study, we examined the effects of intracerebroventricular administration of melanotan II (MTII), a melanocortin agonist, on insulin sensitivity in diet-induced obese (DIO) rats. Although MTII treatment significantly decreased food intake and body weight for 10 days, there was no significant difference in body weight between MTII and pair-fed groups. The insulin tolerance test showed that insulin sensitivity was significantly improved in the MTII group compared to the pair-fed group. Furthermore, MTII treatment increased the number of small-sized adipocytes in epididymal white adipose tissues, suggesting that MTII increased insulin sensitivity through action on the white adipose tissues in DIO rats
Using spin to understand the formation of LIGO's black holes
With the detection of four candidate binary black hole (BBH) mergers by the
Advanced LIGO detectors thus far, it is becoming possible to constrain the
properties of the BBH merger population in order to better understand the
formation of these systems. Black hole (BH) spin orientations are one of the
cleanest discriminators of formation history, with BHs in dynamically formed
binaries in dense stellar environments expected to have spins distributed
isotropically, in contrast to isolated populations where stellar evolution is
expected to induce BH spins preferentially aligned with the orbital angular
momentum. In this work we propose a simple, model-agnostic approach to
characterizing the spin properties of LIGO's BBH population. Using measurements
of the effective spin of the binaries, which is LIGO's best constrained spin
parameter, we introduce a simple parameter to quantify the fraction of the
population that is isotropically distributed, regardless of the spin magnitude
distribution of the population. Once the orientation characteristics of the
population have been determined, we show how measurements of effective spin can
be used to directly constrain the underlying BH spin magnitude distribution.
Although we find that the majority of the current effective spin measurements
are too small to be informative, with LIGO's four BBH candidates we find a
slight preference for an underlying population with aligned spins over one with
isotropic spins (with an odds ratio of 1.1). We argue that it will be possible
to distinguish symmetric and anti-symmetric populations at high confidence with
tens of additional detections, although mixed populations may take
significantly more detections to disentangle. We also derive preliminary spin
magnitude distributions for LIGO's black holes, under the assumption of aligned
or isotropic populations
Identification of precursor transcripts for 6 novel miRNAs expands the diversity on the genomic organisation and expression of miRNA genes in rice
<p>Abstract</p> <p>Background</p> <p>The plant miRNAs represent an important class of endogenous small RNAs that guide cleavage of an mRNA target or repress its translation to control development and adaptation to stresses. MiRNAs are nuclear-encoded genes transcribed by RNA polymerase II, producing a primary precursor that is subsequently processed by DCL1 an RNase III Dicer-like protein.</p> <p>In rice hundreds of miRNAs have been described or predicted, but little is known on their genes and precursors which are important criteria to distinguish them from siRNAs. Here we develop a combination of experimental approaches to detect novel miRNAs in rice, identify their precursor transcripts and genes and predict or validate their mRNA targets.</p> <p>Results</p> <p>We produced four cDNA libraries from small RNA fractions extracted from distinct rice tissues. By <it>in silico </it>analysis we selected 6 potential novel miRNAs, and confirmed that their expression requires OsDCL1. We predicted their targets and used 5'RACE to validate cleavage for three of them, targeting a PPR, an SPX domain protein and a GT-like transcription factor respectively.</p> <p>In addition, we identified precursor transcripts for the 6 miRNAs expressed in rice, showing that these precursors can be efficiently processed using a transient expression assay in transfected <it>Nicotiana benthamiana </it>leaves. Most interestingly, we describe two precursors producing tandem miRNAs, but in distinct arrays. We focus on one of them encoding osa-miR159a.2, a novel miRNA produced from the same stem-loop structure encoding the conserved osa-miR159a.1. We show that this dual osa-miR159a.2-osa-miR159a.1 structure is conserved in distant rice species and maize. Finally we show that the predicted mRNA target of osa-miR159a.2 encoding a GT-like transcription factor is cleaved <it>in vivo </it>at the expected site.</p> <p>Conclusion</p> <p>The combination of approaches developed here identified six novel miRNAs expressed in rice which can be clearly distinguished from siRNAs. Importantly, we show that two miRNAs can be produced from a single precursor, either from tandem stem-loops or tandemly arrayed in a single stem-loop. This suggests that processing of these precursors could be an important regulatory step to produce one or more functional miRNAs in plants and perhaps coordinate cleavage of distinct targets in the same plant tissue.</p
ECCD Experiment Using an Upgraded ECH System on LHD
Electron cyclotron current drive (ECCD) is an attractive tool for controlling plasmas. In the large helical device (LHD), ECCD experiments have been performed by using an EC-wave power source, gyrotron, with a frequency of 84 GHz. The maximum driven current was ?9 kA with 100 kW injection power to plasma and 8 s duration of EC-wave pulse. These years, high-power and long-pulse 77 GHz gyrotrons were newly installed. An ECCD experiment with 775 kW injection power was performed. The 77 GHz waves of 8 s pulse duration sustained the plasmas. The EC-wave beam direction was scanned toroidally, keeping the beam direction aiming at the magnetic axis in X-mode polarization. In spite of the change in the EC-wave beam direction, plasma parameters such as the line-average electron density, the central electron temperature and the plasma stored energy were kept nearly the same values for the discharges, ?0.3 × 1019 m?3, ?3 keV and ?30 kJ, except for the plasma current. The plasma current showed a systematic change with the change in the beam direction for ECCD, and at an optimum direction with N// ? ?0.3, the plasma current reached its maximum, ?40 kA. Also, current drive efficiency normalized with density and power was improved by 50% compared with that at the former 84 GHz ECCD experiment
Recommended from our members
Recombinant human thrombomodulin inhibits neutrophil extracellular trap formation in vitro
The aim of this study was to investigate the effects of recombinant human-soluble thrombomodulin (rTM) on lipopolysaccharide (LPS)-induced, platelet-dependent neutrophil extracellular trap (NET) formation (NETosis). Human peripheral blood neutrophils and platelets were co-incubated with or without LPS (0.2 μg/ml) in the presence and absence of rTM (2 μg/ml). NETosis was confirmed by immunostaining and confocal microscopy. In the absence of platelets, LPS did not induce NETosis in the neutrophils. NETosis, however, was induced by LPS when neutrophils were co-cultured with platelets (64 % of neutrophils). Notably, rTM was able to fully inhibit NETosis in neutrophils cultured with platelets and in the presence of LPS. rTM did not induce NETosis in this co-culture system (p < 0.01 versus LPS in the absence of rTM). These results show that rTM can suppress LPS-induced platelet-dependent NETosis in vitro
Acute Homeostatic Responses to Increased Fat Consumption in MCH1R Knockout Mice
Melanin-concentrating hormone (MCH) is a hypothalamic neuropeptide which has been shown to regulate energy homeostasis. Using genetic knockout mice lacking the MCH1 receptor (MCH1R), we investigated how these mice adapt to metabolic changes caused by excessive caloric consumption. We show that the MCH system is one of the players mediating behavioral and metabolic responses upon increased caloric consumption. MCH1R knockout mice showed decreased tendency of food intake upon exposure to a high-fat diet. They also are resistant to gain weight upon high-fat diet by increasing fat metabolism. Therefore, the MCH system is important in regulating metabolic responses upon various environmental stimuli such as high-fat diet
- …