20 research outputs found

    In Vitro Evaluation of the Antiviral Potential of Guettarda angelica Against Animal Herpesviruses

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    Background: The number of antiviral studies using plant extracts has increased in the last decades, and the results have shown that plants are potential sources of compounds that are able to inhibit and/or decrease viral infections. The selection of these plants by ethnopharmacological criteria increases the probability of finding new substances with significant pharmacological and biological activities. Hence, Brazil has an advantage in this area due to its extensive biodiversity and ethnological diversity. Guettarda angelica is a plant from the Brazilian Caatinga region the roots of which are popularly used for various therapeutic purposes, including veterinary use. The aim of this work was to investigate the in vitro antiviral activity of extracts of plant parts from G. angelica against three animal herpesviruses: bovine (BoHV-1), suid (SuHV-1) and equine (EHV-1) herpesviruses type 1. Materials, Methods & Results: The extracts of roots, leaves and seeds of G. angelica were initially screened for in vitro antiviral activity against these herpesviruses using the virus yield reduction assay. The MDBK cells were used in assays with BoHV-1 and SuHV-1, and the Vero cells with EHV-1. For these assays, the cells previously treated with the extracts in non-cytotoxic concentrations were inoculated with logarithmic dilutions of each virus, The viral inhibitory activity of extracts was calculated by difference of virus titer between treated infected cells and non-treated infected cells. Only the aqueous extract from seeds (AEs) showed a significant antiviral activity (P < 0.01, ANOVA followed by Tukey test) against all herpesviruses leading continuous studies, Thus, the selectivity index (SI) of this extract was determined by MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] colorimetric assay by calculating the ratio CC(50)over IC50. The 50% cytotoxic concentration (CC50) was defined as the extract concentration that reduced the cell viability by 50% when compared to untreated controls; the 50% inhibitory concentration (IC50) was defined as the concentration of the extract that inhibited 50% of viral replication when compared to the virus control. The CC50 and IC50 obtained from nonlinear regression analysis of concentration-effect curves by the GraphPad Prism 5 Demo program and represented the means +/- standard deviation of three independent experiments. The CC5(0) for Vero cells was 400.60 +/- 0.20 mu g/mL, while the CC50 for MDBK cells was 920.50 +/- 0.19 mu g/mL. The IC50 values of the AEs on the BoHV-1, SuHV-1 and EHV-1 were 22.79 mu g/mL, 91.30 mu g/mL and 19.95 mu g/mL, respectively. The SI values of this extract for each virus obtained from these data were 40.39, 10.08 and 20.08 for BoHV-1, SuHV-1, and EHV-1, respectively. Discussion: To ensure the antiviral activity of a plant extract and consequently its future use as antiviral agent is crucial the obtainment of its selectivity index or safety index. It is guarantee of a true antiviral effect and not the result of cytotoxicity of the extract on cells, and that could be confused with an antiviral activity. Other important point are the extract IC50 values less than 100 mu g/mL. The results of the AEs of G. angelica are in accordance with these considerations indicating that the Go angelica seeds may be a potential source of antiviral compounds insurance and encouraging further investigation of them.40

    Polygenic transmission disequilibrium confirms that common and rare variation act additively to create risk for autism spectrum disorders

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    Autism spectrum disorder (ASD) risk is influenced by common polygenic and de novo variation. We aimed to clarify the influence of polygenic risk for ASD and to identify subgroups of ASD cases, including those with strongly acting de novo variants, in which polygenic risk is relevant. Using a novel approach called the polygenic transmission disequilibrium test and data from 6,454 families with a child with ASD, we show that polygenic risk for ASD, schizophrenia, and greater educational attainment is over-transmitted to children with ASD. These findings hold independent of proband IQ. We find that polygenic variation contributes additively to risk in ASD cases who carry a strongly acting de novo variant. Lastly, we show that elements of polygenic risk are independent and differ in their relationship with phenotype. These results confirm that the genetic influences on ASD are additive and suggest that they create risk through at least partially distinct etiologic pathways

    Search for Ultra-high-energy Photons from Gravitational Wave Sources with the Pierre Auger Observatory

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    A search for time-directional coincidences of ultra-high-energy (UHE) photons above 10 EeV with gravitational wave (GW) events from the LIGO/Virgo runs O1 to O3 is conducted with the Pierre Auger Observatory. Due to the distinctive properties of photon interactions and to the background expected from hadronic showers, a subset of the most interesting GW events is selected based on their localization quality and distance. Time periods of 1000 s around and 1 day after the GW events are analyzed. No coincidences are observed. Upper limits on the UHE photon fluence from a GW event are derived that are typically at &amp; SIM;7 MeV cm(-2) (time period 1000 s) and &amp; SIM;35 MeV cm(-2) (time period 1 day). Due to the proximity of the binary neutron star merger GW170817, the energy of the source transferred into UHE photons above 40 EeV is constrained to be less than 20% of its total GW energy. These are the first limits on UHE photons from GW sources

    Arrival Directions of Cosmic Rays above 32 EeV from Phase One of the Pierre Auger Observatory

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    A promising energy range to look for angular correlations between cosmic rays of extragalactic origin and their sources is at the highest energies, above a few tens of EeV (1 EeV equivalent to 10^(18) eV). Despite the flux of these particles being extremely low, the area of similar to 3000 km^(2) covered at the Pierre Auger Observatory, and the 17 yr data-taking period of the Phase 1 of its operations, have enabled us to measure the arrival directions of more than 2600 ultra-high-energy cosmic rays above 32 EeV. We publish this data set, the largest available at such energies from an integrated exposure of 122,000 km^(2) sr yr, and search it for anisotropies over the 3.4 pi steradians covered with the Observatory. Evidence for a deviation in excess of isotropy at intermediate angular scales, with similar to 15 degrees Gaussian spread or similar to 25 degrees top-hat radius, is obtained at the 4 sigma significance level for cosmic-ray energies above similar to 40 EeV

    Searches for Ultra-High-Energy Photons at the Pierre Auger Observatory

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    The Pierre Auger Observatory, which is the largest air-shower experiment in the world, offers unprecedented exposure to neutral particles at the highest energies. Since the start of data collection more than 18 years ago, various searches for ultra-high-energy (UHE, E greater than or similar to 10^(17) eV) photons have been performed, either for a diffuse flux of UHE photons, for point sources of UHE photons or for UHE photons associated with transient events such as gravitational wave events. In the present paper, we summarize these searches and review the current results obtained using the wealth of data collected by the Pierre Auger Observatory

    Multi-messenger observations of a binary neutron star merger

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    On 2017 August 17 a binary neutron star coalescence candidate (later designated GW170817) with merger time 12:41:04 UTC was observed through gravitational waves by the Advanced LIGO and Advanced Virgo detectors. The Fermi Gamma-ray Burst Monitor independently detected a gamma-ray burst (GRB 170817A) with a time delay of ~1.7 s with respect to the merger time. From the gravitational-wave signal, the source was initially localized to a sky region of 31 deg2 at a luminosity distance of 40+8-8 Mpc and with component masses consistent with neutron stars. The component masses were later measured to be in the range 0.86 to 2.26 Mo. An extensive observing campaign was launched across the electromagnetic spectrum leading to the discovery of a bright optical transient (SSS17a, now with the IAU identification of AT 2017gfo) in NGC 4993 (at ~40 Mpc) less than 11 hours after the merger by the One- Meter, Two Hemisphere (1M2H) team using the 1 m Swope Telescope. The optical transient was independently detected by multiple teams within an hour. Subsequent observations targeted the object and its environment. Early ultraviolet observations revealed a blue transient that faded within 48 hours. Optical and infrared observations showed a redward evolution over ~10 days. Following early non-detections, X-ray and radio emission were discovered at the transient’s position ~9 and ~16 days, respectively, after the merger. Both the X-ray and radio emission likely arise from a physical process that is distinct from the one that generates the UV/optical/near-infrared emission. No ultra-high-energy gamma-rays and no neutrino candidates consistent with the source were found in follow-up searches. These observations support the hypothesis that GW170817 was produced by the merger of two neutron stars in NGC4993 followed by a short gamma-ray burst (GRB 170817A) and a kilonova/macronova powered by the radioactive decay of r-process nuclei synthesized in the ejecta

    A Drosophila female pheromone elicits species-specific long-range attraction via an olfactory channel with dual specificity for sex and food

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    Background: Mate finding and recognition in animals evolves during niche adaptation and involves social signals and habitat cues. Drosophila melanogaster and related species are known to be attracted to fermenting fruit for feeding and egg-laying, which poses the question of whether species-specific fly odours contribute to long-range premating communication. Results: We have discovered an olfactory channel in D. melanogaster with a dual affinity to sex and food odorants. Female flies release a pheromone, (Z)-4-undecenal (Z4-11Al), that elicits flight attraction in both sexes. Its biosynthetic precursor is the cuticular hydrocarbon (Z,Z)-7,11-heptacosadiene (7,11-HD), which is known to afford reproductive isolation between the sibling species D. melanogaster and D. simulans during courtship. Twin olfactory receptors, Or69aB and Or69aA, are tuned to Z4-11Al and food odorants, respectively. They are co-expressed in the same olfactory sensory neurons, and feed into a neural circuit mediating species-specific, long-range communication; however, the close relative D. simulans, which shares food resources with D. melanogaster, does not respond to Z4-11Al. Conclusion: The Or69aA and Or69aB isoforms have adopted dual olfactory traits. The underlying gene yields a collaboration between natural and sexual selection, which has the potential to drive speciation
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