The G‐protein‐coupled receptor GPR132, also known as G2A, is activated by 9‐hydroxyoctadecadienoic acid (9‐HODE) and other oxidized fatty acids. Other suggested GPR132 agonists including ...lysophosphatidylcholine (LPC) have not been readily reproduced. Here, we identify N‐acylamides in particular N‐acylglycines, as lipid activators of GPR132 with comparable activity to 9‐HODE. The order‐of‐potency is N‐palmitoylglycine > 9‐HODE ≈ N‐linoleoylglycine > linoleamide > N‐oleoylglycine ≈ N‐stereoylglycine > N‐arachidonoylglycine > N‐docosehexanoylglycine. Physiological concentrations of N‐acylglycines in tissue are sufficient to activate GPR132. N‐linoleoylglycine and 9‐HODE also activate rat and mouse GPR132, despite limited sequence conservation to human. We describe pharmacological tools for GPR132, identified through drug screening. SKF‐95667 is a novel GPR132 agonist. SB‐583831 and SB‐583355 are peptidomimetic molecules containing core amino acids (glycine and phenylalanine, respectively), and structurally related to previously described ligands. A telmisartan analog, GSK1820795A, antagonizes the actions of N‐acylamides at GPR132. The synthetic cannabinoid CP‐55 940 also activates GPR132. Molecular docking to a homology model suggested a site for lipid binding, predicting the acyl side‐chain to extend into the membrane bilayer between TM4 and TM5 of GPR132. Small‐molecule ligands are envisaged to occupy a “classical” site encapsulated in the 7TM bundle. Structure‐directed mutagenesis indicates a critical role for arginine at position 203 in transmembrane domain 5 to mediate GPR132 activation by N‐acylamides. Our data suggest distinct modes of binding for small‐molecule and lipid agonists to the GPR132 receptor. Antagonists, such as those described here, will be vital to understand the physiological role of this long‐studied target.
A three-dimensional (3D) knee joint computational model was developed and validated to predict knee joint contact forces and pressures for different degrees of malalignment. A 3D computational knee ...model was created from high-resolution radiological images to emulate passive sagittal rotation (full-extension to 65°-flexion) and weight acceptance. A cadaveric knee mounted on a six-degree-of-freedom robot was subjected to matching boundary and loading conditions. A ligament-tuning process minimised kinematic differences between the robotically loaded cadaver specimen and the finite element (FE) model. The model was validated by measured intra-articular force and pressure measurements. Percent full scale error between FE-predicted and in vitro-measured values in the medial and lateral compartments were 6.67% and 5.94%, respectively, for normalised peak pressure values, and 7.56% and 4.48%, respectively, for normalised force values. The knee model can accurately predict normalised intra-articular pressure and forces for different loading conditions and could be further developed for subject-specific surgical planning.
ABSTRACT Rotating radio transients (RRATs) are a subclass of pulsars first identified in 2006 that are detected only in searches for single pulses and not through their time averaged emission. Here, ...we present the results of observations of 19 RRATs using the first station of the Long Wavelength Array (LWA1) at frequencies between 30 and 88 MHz. The RRATs observed here were first detected in higher frequency pulsar surveys. Of the 19 RRATs observed, two sources were detected and their dispersion measures, periods, pulse profiles, and flux densities are reported and compared to previous higher frequency measurements. We find a low detection rate (11%), which could be a combination of the lower sensitivity of LWA1 compared to higher frequency telescopes, and the result of scattering by the interstellar medium or a spectral turnover.
Using the narrowband all‐sky imager mode of the Long Wavelength Array (LWA1), we have now detected 30 transients at 25.6 MHz, 1 at 34 MHz, and 93 at 38.0 MHz. While we have only optically confirmed ...that 37 of these events are radio afterglows from meteors, evidence suggests that most, if not all, are. Using the beam‐forming mode of the LWA1, we have also captured the broadband spectra between 22.0 and 55.0 MHz of four events. We compare the smooth, spectral components of these four events and fit the frequency‐dependent flux density to a power law, and find that the spectral index is time variable, with the spectrum steepening over time for each meteor afterglow. Using these spectral indices along with the narrowband flux density measurements of the 123 events at 25.6 and 38 MHz, we predict the expected flux densities and rates for meteor afterglows potentially observable by other low‐frequency radio telescopes.
Key Points
We have computed rates of meteor radio afterglows
We have measured the spectra of four meteor radio afterglows and have fit them to a power law
We use the power law fit and the measured rates to predict event rates for other telescopes at other frequencies
Abstract Classical music has been shown to reduce stress in kennelled dogs; however, rapid habituation of dogs to this form of auditory enrichment has also been demonstrated. The current study ...investigated the physiological and behavioural response of kennelled dogs ( n = 38) to medium-term (5 days) auditory enrichment with five different genres of music including Soft Rock, Motown, Pop, Reggae and Classical, to determine whether increasing the variety of auditory stimulation reduces the level of habituation to auditory enrichment. Dogs were found to spend significantly more time lying and significantly less time standing when music was played, regardless of genre. There was no observable effect of music on barking, however, dogs were significantly (z = 2.2, P < 0.05) more likely to bark following cessation of auditory enrichment. Heart Rate Variability (HRV) was significantly higher, indicative of decreased stress, when dogs were played Soft Rock and Reggae, with a lesser effect observed when Motown, Pop and Classical genres were played. Relative to the silent period prior to auditory enrichment, urinary cortisol:creatanine (UCCR) values were significantly higher during Soft Rock ( t = 2.781, P < 0.01) and the second silent control period following auditory enrichment ( t = 2.46, P < 0.05). Despite the mixed response to different genres, the physiological and behavioural changes observed remained constant over the 5d of enrichment suggesting that the effect of habituation may be reduced by increasing the variety of auditory enrichment provided.
The ability of 26 younger (mean age was 22.5 years) and older adults (mean age was 72.6 years) to haptically perceive material properties was evaluated. The participants manually explored (for 5 ...seconds) 42 surfaces twice and placed each of these 84 experimental stimuli into one of seven categories: paper, plastic, metal, wood, stone, fabric, and fur/leather. In general, the participants were best able to identify fur/leather and wood materials; in contrast, recognition performance was worst for stone and paper. Despite similar overall patterns of performance for younger and older participants, the younger adults’ recognition accuracies were 26.5% higher. The participants’ tactile acuities (assessed by tactile grating orientation discrimination) affected their ability to identify surface material. In particular, the Pearson r correlation coefficient relating the participants’ grating orientation thresholds and their material identification performance was −0.8: The higher the participants’ thresholds, the lower the material recognition ability. While older adults are able to effectively perceive the solid shape of environmental objects using the sense of touch, their ability to perceive surface materials is significantly compromised.
Modern techniques for specifying the ionosphere include the use of ionosondes, which both transmit and receive sweep soundings in the high‐frequency (HF) band. We replicate this process by observing ...the broad band emission from lightning using the Long Wavelength Array, Sevilleta, radio telescope. We use this station to observe the powerful broadband radio bursts from the breakdown of air that occurs during lightning flashes. For nearby lightning we observe both the direct line of sight and the delayed ionospheric reflection. By correlating the amplitude time series from the direct line of sight to that of the ionospheric reflection, we can accurately measure the group delay as a function of frequency. By separating into right‐hand circular and left‐hand circular, we can derive both the O mode and X mode ionograms. This novel technique allows for accurate ionograms to be made even in restricted frequency bands and provides a means to probe density profiles at multiple locations of the ionosphere on short time scales with a single receiver station.
Plain Language Summary
In this paper, we present a novel technique that leverages the natural radio emissions from lightning as a signal source to measure the electron density profile of the bottomside ionosphere. Such profile measurements are known as ionograms. Previous methods to produce ionograms make use of RADAR systems composed of both a transmitter and receiver. Our method, however, requires only a receiver placed in proximity to ongoing lightning storms. These measurements are the first of their kind to use naturally occurring radio emission to produce ionograms. This work opens the door to further research, where scattered storms could provide key measurements for specifying the spatial and temporal structure present within the ionosphere.
Key Points
Lightning generates the required signal needed for ionospheric specification
The ionograms presented here are the first to be derived from lightning measurements
Measurements are not subject to frequency restrictions
The budding yeast, Saccharomyces cerevisiae, is a convenient system for coupling heterologous G protein-coupled receptors (GPCRs) to the pheromone response pathway to facilitate empirical ligand ...screening and/or GPCR mutagenesis studies. However, few studies have applied this system to define GPCR-G protein-coupling preferences and furnish information on ligand affinities, efficacies, and functional selectivity. We thus used different S. cerevisiae strains, each expressing a specific human Galpha/yeast Gpa1 protein chimera, and determined the pharmacology of various ligands of the coexpressed human adenosine A(1) receptor. These assays, in conjunction with the application of quantitative models of agonism and antagonism, revealed that (-)-N(6)-(2-phenylisopropyl)adenosine was a high-efficacy agonist that selectively coupled to Gpa/1Galpha(o), Gpa1/Galpha(i1/2), and Gpa1/Galpha(i3), whereas the novel compound, 5'-deoxy-N(6)-(endo-norborn-2-yl)-5'-(2-fluorophenylthio)adenosine (VCP-189), was a lower-efficacy agonist that selectively coupled to Gpa1/Galpha(i) proteins; the latter finding suggested that VCP-189 might be functionally selective. The affinity of the antagonist, 8-cyclopentyl-1,3-dipropylxanthine, was also determined at the various strains. Subsequent experiments performed in mammalian Chinese hamster ovary cells monitoring cAMP formation/inhibition, intracellular calcium mobilization, phosphorylation of extracellular signal-regulated kinase 1 and 2 or (35)S-labeled guanosine 5'-(gamma-thio)triphosphate binding, were in general agreement with the yeast data regarding agonist efficacy estimation and antagonist affinity estimation, but revealed that the apparent functional selectivity of VCP-189 could be explained by differences in stimulus-response coupling between yeast and mammalian cells. Our results suggest that this yeast system is a useful tool for quantifying ligand affinity and relative efficacy, but it may lack the sensitivity required to detect functional selectivity of low-efficacy agonists.
Loss of PTEN tumor suppressor function is observed in tumors of breast, prostate, thyroid, and endometrial origin. Allelic losses in the proximity of the PTEN locus (10q23) also occur in sporadic ...colorectal cancers (CRCs), but biallelic inactivation of this site has not been frequently demonstrated. We hypothesized that alternative mechanisms of PTEN allelic inactivation, such as promoter hypermethylation, might be operative in CRC and that PTEN inactivation may be related to recognized forms of genomic instability. We characterized a cohort of 273 sporadic CRCs by determining their microsatellite instability (MSI) status. Of these, 146 cancers were examined for PTEN promoter methylation by methylation-specific PCR. Mutations at the poly(A)6 repeat sequences in PTEN exons 7 and 8 and deletions at the 10q23 locus were also identified using microsatellite analysis. The presence of PTEN protein was determined by immunostaining, and the results were correlated with the promoter methylation status. We observed that PTEN promoter hypermethylation was a frequent occurrence in MSI-high (MSI-H) tumors (19.1% of MSI-H versus 2.2% of MSI-low/microsatellite stable tumors; P = 0.002). A PTEN mutation or a deletion event was present in 60% of the tumors with promoter region hypermethylation. Hypermethylation of the PTEN promoter correlated significantly with either decreased or complete loss of PTEN protein expression (P = 0.004). This is the first demonstration of PTEN inactivation as a result of promoter hypermethylation in MSI-H sporadic CRCs. These data suggest that this silencing mechanism plays a major role in PTEN inactivation and, in colon cancer, may be more important than either allelic losses or inactivating mutations. The significant correlation of PTEN hypermethylation with MSI-H tumors further suggests that PTEN is an additional important "target" of methylation along with the hMLH1 gene in the evolution of MSI-H CRCs and also confers the "second hit" in the biallelic inactivation mechanism for some proportion of tumors.
PDF
