1,865 research outputs found

    Expression patterns of intronic microRNAs in Caenorhabditis elegans

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    BACKGROUND: MicroRNAs (miRNA) are an abundant and ubiquitous class of small RNAs that play prominent roles in gene regulation. A significant fraction of miRNA genes reside in the introns of the host genes in the same orientation and are thought to be co-processed from the host gene mRNAs and thus depend on the host gene promoter for their expression. However, several lines of evidence for independent expression of intronic miRNAs exist in the literature but the extent of this independence remains unclear. RESULTS: We performed a systematic analysis of genomic regions surrounding intronic miRNAs in the nematode Caenorhabditis elegans and found that, in many cases, there are extended intronic sequences immediately upstream of the miRNAs that are well-conserved between the nematodes. We have generated transcriptional green fluorescent protein reporter fusions in transgenic C. elegans lines and demonstrated that, in all seven investigated cases, the conserved sequences show promoter properties and produce specific expression patterns that are different from the host gene expression patterns. The observed expression patterns are corroborated by the published small RNA sequencing data. CONCLUSIONS: Our analysis reveals that the number of intronic miRNAs that do not rely on their host genes for expression is substantially higher than previously appreciated. At least one-third of the same-strand intronic miRNAs in C. elegans posses their own promoters and, thus, could be transcribed independently from their host genes. These findings provide a new insight into the regulation of miRNA genes and will be useful for the analysis of interactions between miRNAs and their host genes.

    Workshop on reconstruction schemes for magnetic resonance data: summary of findings and recommendations

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    [EN] The high fidelity reconstruction of compressed and low-resolution magnetic resonance (MR) data is essential for simultaneously improving patient care, accuracy in diagnosis and quality in clinical research. Sponsored by the Royal Society through the Newton Mobility Grant Scheme, we held a half-day workshop on reconstruction schemes for MR data on the 17 of August 2016 to discuss new ideas from related research fields that could be useful to overcome the shortcomings of the conventional reconstruction methods that have been evaluated up to date. Participants were 21 university students, computer scientists, image analysts, engineers and physicists from institutions from 6 different countries. The discussion evolved around exploring new avenues to achieve high resolution, high quality and fast acquisition of MR imaging. In this article, we summarise the topics covered throughout the workshop and make recommendations for ongoing and future works.The workshop was sponsored by the Royal Society through the Newton Mobility Grant NI150340 to E.O.-I. and M.C.V.H. M.C.V.H. is funded by Row Fogo Charitable Trust; R.O.R. is funded by the Ministry of Education, Research, Culture and Sports of Valencia (Spain) under the programme VALi+d 2015; E.O.-I. is funded by Bogazici University, and the research presented at the workshop was supported by TUBITAK Career Development Grant 112E036, EU Marie Curie IRG Grant FP7-PEOPLE-RG-2009 256528, Tubitak 1001 Research Grant 115S219, and Bogazici University BAP Grant 10844SUP; I.M. is funded by core funds from the University of Edinburgh, including the Scottish Funding Council; A.J.V.B. is funded by the Marie Sklodowska Curie scholarship which is part of the European Union's H2020 Framework Programme (H2020-MSCA-ITN-2014) under the grant agreement number 642685 MacSeNet; and V.G.O. and P.F. are privately funded.Ozturk-Isik, E.; Marshall, I.; Filipiak, P.; Benjamin, AJV.; Ones, VG.; Ortiz-Ramón, R.; Valdes Hernandez, MDC. (2017). Workshop on reconstruction schemes for magnetic resonance data: summary of findings and recommendations. Royal Society Open Science. 4(2):1-4. https://doi.org/10.1098/rsos.160731144

    Infection and transmission of Cache Valley virus by Aedes albopictus and Aedes aegypti mosquitoes

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    Background: Cache Valley virus (CVV; Bunyavirales, Peribunyaviridae) is a mosquito-borne arbovirus endemic in North America. Although severe diseases are mainly observed in pregnant ruminants, CVV has also been recognized as a zoonotic pathogen that can cause fatal encephalitis in humans. Human exposures to CVV and its related subtypes occur frequently under different ecological conditions in the New World; however, neurotropic disease is rarely reported. High prevalence rates of neutralizing antibodies have been detected among residents in several Latin American cities. However, zoophilic mosquito species involved in the enzootic transmission are unlikely to be responsible for the transmission leading to human exposures to CVV. Mechanisms that lead to frequent human exposures to CVV remain largely unknown. In this study, competence of two anthropophilic mosquitoes, Aedes albopictus and Ae. aegypti, for CVV was determined using per os infection to determine if these species could play a role in the transmission of CVV in the domestic and peridomestic settings of urban and suburban areas. Results: Aedes albopictus were highly susceptible to CVV whereas infection of Ae. aegypti occurred at a significantly lower frequency. Whilst the dissemination rates of CVV were comparable in the two species, the relatively long period to attain maximal infectious titer in Ae. aegypti demonstrated a significant difference in the replication kinetics of CVV in these species. Detection of viral RNA in saliva suggests that both Ae. albopictus and Ae. aegypti are competent vectors for CVV under laboratory conditions. Conclusions: Differential susceptibility to CVV was observed in Ae. albopictus and Ae. aegypti, reflecting their relatively different capacities for vectoring CVV in nature. The high susceptibility of Ae. albopictus to CVV observed in this study suggests its potential role as an efficient vector for CVV. Complemented by the reports of multiple CVV isolates derived from Ae. albopictus, our finding provides the basis for how the dispersal of Ae. albopictus across the New World may have a significant impact on the transmission and ecology of CVV

    Constraints on the χ_(c1) versus χ_(c2) polarizations in proton-proton collisions at √s = 8 TeV

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    The polarizations of promptly produced χ_(c1) and χ_(c2) mesons are studied using data collected by the CMS experiment at the LHC, in proton-proton collisions at √s=8  TeV. The χ_c states are reconstructed via their radiative decays χ_c → J/ψγ, with the photons being measured through conversions to e⁺e⁻, which allows the two states to be well resolved. The polarizations are measured in the helicity frame, through the analysis of the χ_(c2) to χ_(c1) yield ratio as a function of the polar or azimuthal angle of the positive muon emitted in the J/ψ → μ⁺μ⁻ decay, in three bins of J/ψ transverse momentum. While no differences are seen between the two states in terms of azimuthal decay angle distributions, they are observed to have significantly different polar anisotropies. The measurement favors a scenario where at least one of the two states is strongly polarized along the helicity quantization axis, in agreement with nonrelativistic quantum chromodynamics predictions. This is the first measurement of significantly polarized quarkonia produced at high transverse momentum

    Differential Cross Sections and Cross-Section Ratios for the Electron-Impact Excitation of the Neon 2p⁵3s Configuration

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    Electron-impact differential cross-section measurements for the excitation of the 2p53s configuration of Ne are reported. The Ne cross sections are obtained using experimental differential cross sections for the electron-impact excitation of the n = 2 levels of atomic hydrogen [Khakoo et al., Phys. Rev. A 61, 012701-1 (1999)], and existing experimental helium differential cross-section measurements, as calibration standards. These calibration measurements were made using the method of gas mixtures (Ne and H followed by Ne and He), in which the gas beam profiles of the mixed gases are found to be the same within our experimental errors. We also present results from calculations of these differential cross sections using the R-matrix and unitarized first-order many-body theory, the distorted-wave Born approximation, and relativistic distorted-wave methods. Comparison with available experimental differential cross sections and differential cross-section ratios is also presented