564 research outputs found
Multi-messenger observations of a binary neutron star merger
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
AMPK in Pathogens
During host–pathogen interactions, a complex web of events is crucial for the outcome of infection. Pathogen recognition triggers powerful cellular signaling events that is translated into the induction and maintenance of innate and adaptive host immunity against infection. In opposition, pathogens employ active mechanisms to manipulate host cell regulatory pathways toward their proliferation and survival. Among these, subversion of host cell energy metabolism by pathogens is currently recognized to play an important role in microbial growth and persistence. Extensive studies have documented the role of AMP-activated protein kinase (AMPK) signaling, a central cellular hub involved in the regulation of energy homeostasis, in host–pathogen interactions. Here, we highlight the most recent advances detailing how pathogens hijack cellular metabolism by suppressing or increasing the activity of the host energy sensor AMPK. We also address the role of lower eukaryote AMPK orthologues in the adaptive process to the host microenvironment and their contribution for pathogen survival, differentiation, and growth. Finally, we review the effects of pharmacological or genetic AMPK modulation on pathogen growth and persistence.CIHR -Canadian Institutes of Health Researc
Plastid phylogenomics resolves ambiguous relationships within the orchid family and provides a solid timeframe for biogeography and macroevolution
Recent phylogenomic analyses based on the maternally inherited plastid organelle have enlightened evolutionary relationships between the subfamilies of Orchidaceae and most of the tribes. However, uncertainty remains within several subtribes and genera for which phylogenetic relationships have not ever been tested in a phylogenomic context. To address these knowledge-gaps, we here provide the most extensively sampled analysis of the orchid family to date, based on 78 plastid coding genes representing 264 species, 117 genera, 18 tribes and 28 subtribes. Divergence times are also provided as inferred from strict and relaxed molecular clocks and birth–death tree models. Our taxon sampling includes 51 newly sequenced plastid genomes produced by a genome skimming approach. We focus our sampling efforts on previously unplaced clades within tribes Cymbidieae and Epidendreae. Our results confirmed phylogenetic relationships in Orchidaceae as recovered in previous studies, most of which were recovered with maximum support (209 of the 262 tree branches). We provide for the first time a clear phylogenetic placement for Codonorchideae within subfamily Orchidoideae, and Podochilieae and Collabieae within subfamily Epidendroideae. We also identify relationships that have been persistently problematic across multiple studies, regardless of the different details of sampling and genomic datasets used for phylogenetic reconstructions. Our study provides an expanded, robust temporal phylogenomic framework of the Orchidaceae that paves the way for biogeographical and macroevolutionary studies.Universidad de Costa Rica/[814-B8-257]/UCR/Costa RicaUniversidad de Costa Rica/[814-B6-140]/UCR/Costa RicaIDEA WILD/[]//Estados UnidosSociedad Colombiana de Orquideología/[]/SCO/ColombiaFundação de Amparo à Pesquisa do Estado de São Paulo/[11/08308-9]/FAPESP/BrasilFundação de Amparo à Pesquisa do Estado de São Paulo/[13/19124-1]/FAPESP/BrasilSwiss Orchid Foundation/[]//SuizaRoyal Botanic Gardens, Kew/[]//InglaterraSwedish Research Council/[2019-05191]//SueciaSwedish Foundation for Strategic Research/[FFL15-0196]/SSF/SueciaUCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias Agroalimentarias::Jardín Botánico Lankester (JBL
The PedsQL™ as a patient-reported outcome in children and adolescents with Attention-Deficit/Hyperactivity Disorder: a population-based study
BACKGROUND: Attention-Deficit/Hyperactivity Disorder (ADHD) is the most common chronic mental health condition in children and adolescents. The application of health-related quality of life (HRQOL) as a pediatric population health measure may facilitate risk assessment and resource allocation, the identification of health disparities, and the determination of health outcomes from interventions and policy decisions for children and adolescents with ADHD at the local community, state, and national health level. METHODS: An analysis from an existing statewide database to determine the feasibility, reliability, and validity of the 23-item PedsQL™ 4.0 (Pediatric Quality of Life Inventory™) Generic Core Scales as a patient-reported outcome (PRO) measure of pediatric population health for children and adolescents with ADHD. The PedsQL™ 4.0 Generic Core Scales (Physical, Emotional, Social, School Functioning) were completed by families through a statewide mail survey to evaluate the HRQOL of new enrollees in the State of California State's Children's Health Insurance Program (SCHIP). Seventy-two children ages 5–16 self-reported their HRQOL. RESULTS: The PedsQL™ 4.0 evidenced minimal missing responses, achieved excellent reliability for the Total Scale Score (α = 0.92 child self-report, 0.92 parent proxy-report), and distinguished between healthy children and children with ADHD. Children with ADHD self-reported severely impaired psychosocial functioning, comparable to children with newly-diagnosed cancer and children with cerebral palsy. CONCLUSION: The results suggest that population health monitoring may identify children with ADHD at risk for adverse HRQOL. The implications of measuring pediatric HRQOL for evaluating the population health outcomes of children with ADHD internationally are discussed
Molecular and Evolutionary Bases of Within-Patient Genotypic and Phenotypic Diversity in Escherichia coli Extraintestinal Infections
Although polymicrobial infections, caused by combinations of viruses, bacteria, fungi and parasites, are being recognised with increasing frequency, little is known about the occurrence of within-species diversity in bacterial infections and the molecular and evolutionary bases of this diversity. We used multiple approaches to study the genomic and phenotypic diversity among 226 Escherichia coli isolates from deep and closed visceral infections occurring in 19 patients. We observed genomic variability among isolates from the same site within 11 patients. This diversity was of two types, as patients were infected either by several distinct E. coli clones (4 patients) or by members of a single clone that exhibit micro-heterogeneity (11 patients); both types of diversity were present in 4 patients. A surprisingly wide continuum of antibiotic resistance, outer membrane permeability, growth rate, stress resistance, red dry and rough morphotype characteristics and virulence properties were present within the isolates of single clones in 8 of the 11 patients showing genomic micro-heterogeneity. Many of the observed phenotypic differences within clones affected the trade-off between self-preservation and nutritional competence (SPANC). We showed in 3 patients that this phenotypic variability was associated with distinct levels of RpoS in co-existing isolates. Genome mutational analysis and global proteomic comparisons in isolates from a patient revealed a star-like relationship of changes amongst clonally diverging isolates. A mathematical model demonstrated that multiple genotypes with distinct RpoS levels can co-exist as a result of the SPANC trade-off. In the cases involving infection by a single clone, we present several lines of evidence to suggest diversification during the infectious process rather than an infection by multiple isolates exhibiting a micro-heterogeneity. Our results suggest that bacteria are subject to trade-offs during an infectious process and that the observed diversity resembled results obtained in experimental evolution studies. Whatever the mechanisms leading to diversity, our results have strong medical implications in terms of the need for more extensive isolate testing before deciding on antibiotic therapies
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VERITAS and Multiwavelength Observations of the Blazar B3 2247+381 in Response to an IceCube Neutrino Alert
While the sources of the diffuse astrophysical neutrino flux detected by the IceCube Neutrino Observatory are still largely unknown, one of the promising methods to improve our understanding of them is investigating the potential temporal and spatial correlations between neutrino alerts and the electromagnetic radiation from blazars. We report on the multiwavelength target-of-opportunity observations of the blazar B3 2247+381, taken in response to an IceCube multiplet alert for a cluster of muon neutrino events compatible with the source location between 2022 May 20 and 2022 November 10. B3 2247+381 was not detected with VERITAS during this time period. The source was found to be in a low-flux state in the optical, ultraviolet, and gamma-ray bands for the time interval corresponding to the neutrino event, but was detected in the hard X-ray band with NuSTAR during this period. We find the multiwavelength spectral energy distribution is described well using a simple one-zone leptonic synchrotron self-Compton radiation model. Moreover, assuming the neutrinos originate from hadronic processes within the jet, the neutrino flux would be accompanied by a photon flux from the cascade emission, and the integrated photon flux required in such a case would significantly exceed the total multiwavelength fluxes and the VERITAS upper limits presented here. The lack of flaring activity observed with VERITAS, combined with the low multiwavelength flux levels, as well as the significance of the neutrino excess being at a 3σ level (uncorrected for trials), makes B3 2247+381 an unlikely source of the IceCube multiplet. We conclude that the neutrino excess is likely a background fluctuation
Natural History of MYH7-Related Dilated Cardiomyopathy
BACKGROUND: Variants in myosin heavy chain 7 (MYH7) are responsible for disease in 1% to 5% of patients with dilated cardiomyopathy (DCM); however, the clinical characteristics and natural history of MYH7-related DCM are poorly described. OBJECTIVE: We sought to determine the phenotype and prognosis of MYH7-related DCM. We also evaluated the influence of variant location on phenotypic expression. METHODS: We studied clinical data from 147 individuals with DCM-causing MYH7 variants (47.6% female; 35.6 ± 19.2 years) recruited from 29 international centers. RESULTS: At initial evaluation, 106 (72.1%) patients had DCM (left ventricular ejection fraction: 34.5% ± 11.7%). Median follow-up was 4.5 years (IQR: 1.7-8.0 years), and 23.7% of carriers who were initially phenotype-negative developed DCM. Phenotypic expression by 40 and 60 years was 46% and 88%, respectively, with 18 patients (16%) first diagnosed at <18 years of age. Thirty-six percent of patients with DCM met imaging criteria for LV noncompaction. During follow-up, 28% showed left ventricular reverse remodeling. Incidence of adverse cardiac events among patients with DCM at 5 years was 11.6%, with 5 (4.6%) deaths caused by end-stage heart failure (ESHF) and 5 patients (4.6%) requiring heart transplantation. The major ventricular arrhythmia rate was low (1.0% and 2.1% at 5 years in patients with DCM and in those with LVEF of ≤35%, respectively). ESHF and major ventricular arrhythmia were significantly lower compared with LMNA-related DCM and similar to DCM caused by TTN truncating variants. CONCLUSIONS: MYH7-related DCM is characterized by early age of onset, high phenotypic expression, low left ventricular reverse remodeling, and frequent progression to ESHF. Heart failure complications predominate over ventricular arrhythmias, which are rare
Testing the Efficacy of a Multi-Component DNA-Prime/DNA-Boost Vaccine against Trypanosoma cruzi Infection in Dogs
Immunization of dogs with DNA-prime/DNA-boost vaccine (TcVac1) enhanced the
Trypanosoma cruzi-specific type 1 antibody and
CD8+ T cell responses that resulted in an early control of
acute parasitemia and a moderate decline in pathological symptoms during chronic
phase. Further improvement of vaccine-induced immunity would be required to
achieve clinical and epidemiological benefits and prevent transmission of
parasites from vaccinated/infected dogs to triatomines
The impact of transposable element activity on therapeutically relevant human stem cells
Human stem cells harbor significant potential for basic and clinical translational research as well as regenerative
medicine. Currently ~ 3000 adult and ~ 30 pluripotent stem cell-based, interventional clinical trials are ongoing
worldwide, and numbers are increasing continuously. Although stem cells are promising cell sources to treat a
wide range of human diseases, there are also concerns regarding potential risks associated with their clinical use,
including genomic instability and tumorigenesis concerns. Thus, a deeper understanding of the factors and
molecular mechanisms contributing to stem cell genome stability are a prerequisite to harnessing their therapeutic
potential for degenerative diseases. Chemical and physical factors are known to influence the stability of stem cell
genomes, together with random mutations and Copy Number Variants (CNVs) that accumulated in cultured human
stem cells. Here we review the activity of endogenous transposable elements (TEs) in human multipotent and
pluripotent stem cells, and the consequences of their mobility for genomic integrity and host gene expression. We
describe transcriptional and post-transcriptional mechanisms antagonizing the spread of TEs in the human genome,
and highlight those that are more prevalent in multipotent and pluripotent stem cells. Notably, TEs do not only
represent a source of mutations/CNVs in genomes, but are also often harnessed as tools to engineer the stem cell
genome; thus, we also describe and discuss the most widely applied transposon-based tools and highlight the
most relevant areas of their biomedical applications in stem cells. Taken together, this review will contribute to the
assessment of the risk that endogenous TE activity and the application of genetically engineered TEs constitute for
the biosafety of stem cells to be used for substitutive and regenerative cell therapiesS.R.H. and P.T.R. are funded by the Government of Spain (MINECO, RYC-2016-
21395 and SAF2015–71589-P [S.R.H.]; PEJ-2014-A-31985 and SAF2015–71589-
P [P.T.R.]). GGS is supported by a grant from the Ministry of Health of the
Federal Republic of Germany (FKZ2518FSB403)
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