792 research outputs found
Use of bacterial Rho helicase to gain new insights into the targeting mechanism of nuclear RNAs by the exosome-associated exoribonuclease Rrp6 and its cofactors in yeast
In eukaryotic cells, aberrant mRNPs with processing and packaging defects are targeted co-transcriptionally by a surveillance system that triggers their nuclear retention and ultimately the degradation of their mRNA component by the 3’-5’ activity of the exosome-associated exoribonuclease Rrp6 along with its associated factors Rrp47 and Mpp6. This mRNP quality control process is stimulated by the NNS complex (Nrd1-Nab3-Sen1), which otherwise mediates termination, processing and decay of ncRNAs and the process involves additionally the exosome co-activator TRAMP complex (Trf4-Air2-Mtr4). Here, we describe a genome-wide approach to visualize the dynamic recruitment of these quality control components over the yeast chromosomes upon global perturbation of mRNP biogenesis by the RNA-dependent helicase/translocase activity of the bacterial Rho factor.
The method provides valuable information on how the surveillance system coordinates with the transcription machinery in order to detect faulty events during perturbation of mRNP biogenesis. In addition, our overview shows that the assembly of the quality control components for the affected mRNA genes takes place at the expense of their commitment to be recruited to ncRNAs genomic features, which in turn leads to termination and processing defects of ncRNAs.</p
Methodological approach for creating an IoT manufacturing application
With the heterogeneity and diversity of electronic systems and their memory capacity, the Internet of Things technologies face several challenges, such as the difficulty in choosing a growing catalogue of IoT technologies and the lack of interoperability of these technologies. This leads to the creation of particular IoT architectures and to the selection of IoT technologies by trying and error approaches. We propose a methodological approach for creating an IoT application guided by the users’ needs and by the contextual environment. It enables the user to select the right hardware guided by the market supply and to check the performances of the IoT solutions. We implement and test our proposition in a picking system of a manufacturing factory. This practical implementation provides feedback regarding our methodological approach for creating an IoT application, which in turn enables us to improve and remodel the approach.info:eu-repo/semantics/acceptedVersio
On a Low-Frequency and Contrast Stabilized Full-Wave Volume Integral Equation Solver for Lossy Media
In this article, we present a new regularized electric flux volume integral equation (D-VIE) for modeling high-contrast conductive dielectric objects in a broad frequency range. This new formulation is particularly suitable for modeling biological tissues at low frequencies, as it is required by brain epileptogenic area imaging, but also at higher ones, as it is required by several applications, including, but not limited to, deep brain stimulation (DBS). When modeling inhomogeneous objects with high complex permittivities at low frequencies, the traditional D-VIE is ill-conditioned and suffers from numerical instabilities that result in slower convergence and less accurate solutions. In this work, we address these shortcomings by leveraging a new set of volume quasi-Helmholtz projectors. Their scaling by the material permittivity matrix allows for the rebalancing of the equation when applied to inhomogeneous scatterers and, thereby, makes the proposed method accurate and stable even for high complex permittivity objects until arbitrarily low frequencies. Numerical results, canonical and realistic, corroborate the theory and confirm the stability and the accuracy of this new method both in the quasi-static regime and at higher frequencies
Les Algues Indicatrices De L'eutrophisation Et De La Contamination De La Lagune De Korba (Cap Bon Tunisie)
The concentrations of heavy metals (Fe, Zn, Pb and Mn) were determined in two green algae (Enteromorpha intestinalis and Chaetomorpha Linium) collected from April 2012 to February 2013 in nine stations characterized by the abundance of these algae throughout the year. Determination of Pb, Mn and Zn was carried out by graphite furnace atomic absorption spectrometer while Fe by flame atomic absorption spectrometer (using the Thermo Scientific ICE 3300 AA Spectrometer). An evaluation of the degree of eutrophication is made through the physicochemical study of 31 samples in the surface water. The results underline that Korba is an eutrophic lagoon. The heavy metal concentrations in the water samples decreased in the sequence of Fe >Zn > Mn > Pb, while in Chaetomorpha Linium, Enteromorpha intestinalis and sediment exhibited the same pattern across the sites: Fe >Mn> Zn >Pb. The results show that metal accumulation capacity in both macro-algae varies according to the season and depends on the species. By comparison with other studies in the world, the levels found in the algae of Korba lagoon are relatively high except Mn. Chaetomorpha Linium could be used as an excellent indicator for heavy metals accumulation in Korba lagoon
Productivity, heritability and stability analysis of a Moroccan sugar beet germplasm
Received: January 19th, 2021 ; Accepted: March 27th, 2021 ; Published: April 6th 2021 ; Correspondence: [email protected] testing is the second part of maternal recurrent selection scheme adopted by
INRA-Morocco for the national sugar beet breeding programme. The objective of this study is
sugar beet germplasm productivity, heritability and stability analysis. The studied material
concern 18 half-sib families (HSF) preselected initially for their seed production potential. Trials
were conducted using randomised complete blocks designs during, 2013/14, 2014/15, 2015/16,
2017/18 campaigns in two experimental fields of INRA-Morocco; Sidi Allal Tazi (34° 30' N, 6°
19' W) and Larache (35° 11’ N, 6° 09’ W). Evaluated parameters concern the vigour, root weight
(RW), leaf biomass yield (LBY), and sugar content (Sc). Data analysis by comparative
procedures explores different accordance degrees of HSF versus controls. Good vegetative
growth was observed, 85.6% closer to the maximal indicated scale level. The RW was
significantly influenced by the genotype and reached a maximum of 1.06 kg versus 1.08 kg
average recorded by controls. Sugar content recorded mean was 20.97% in HSF versus 21.39%
in the controls. Most of HSF revealed mean values close to Z-type variety. Estimated heritability
was 0.5 for RW, 0.2 for the LBY, and 0.02 for Sc. Sugar content was influenced by the
environment and explained by the AMMI model (73.6%) versus 53.9% and 44.4% for root weight
and leaf biomass yield respectively. The AMMI stability values showed F11, F12, F16, and F17
families as the most performing and stable HSF. Results demonstrate the relevance of the
maternal recurrent selection scheme of the on-going national breeding programme
Toxicity and neurophysiological impacts of three plant-derived essential oils against the vineyard mealybug Planococcus ficus
Many natural products are able to control pests and can be used as alternatives for chemical treatments. Plant essential oils (EOs) have been found to exhibit some biological activity against many insects including mealybugs. This study aimed at studying the insecticidal activity and behavioral and neurophysiological impacts of three plant essential oils against the vine mealybug Planococcus ficus. The topical and fumigant toxicity of Cymbopogon citratus, Mentha piperita, and Pelargonium graveolens essential oils was evaluated against P. ficus adults. The chemical composition analysis of EOs by gas chromatographic-mass spectrometry (GC-MS) revealed citronellal (31.69 %), menthol (73.78 %), and geraniol (39.6%), as major components, respectively. Bioassays of EOs against vine mealybug adults through fumigation toxicity method revealed lethal concentrations LC50 values of 17.01, 26.27 and 24.52 µL·L-1 air for C. citratus, M. piperita, and P. graveolens, respectively. In both topical and fumigant bioassays, essential oil from C. citratus was the most active altering the behavioral response of treated mealybugs which becomes hyperactive and disoriented. EOs induced general stress in P. ficus adults, as evidenced by oxidative stress biomarker analyses. Biochemical analyses showed that the EOs exposure reduced the activity of acetylcholinesterase and significantly induced the glutathione S-transferases and Malondialdehydes accumulation in the vine mealybug tissues. Mortality caused by lemongrass EO positively correlated with the significant decrease in the AChE activity indicating lethal neurological effects. These toxicity bioassays and neurological impact findings provide new informations for formulating effective essential oil based-insecticides to control P. ficus in the framework of integrated pest management programs
Coda wave attenuation tomography in Northern Morocco
In this study we focused on seismic attenuation (1/ Q) tomography in Northern Morocco. For this purpose, two different models are employed: The Single Backscattering model hypothesis of Aki and Chouet (1975) to calculate values of Coda Q (Q) and the Back-projection technique of Xie and Mitchell (1990) to estimate lateral variation in Q via a tomographic inversion. For this investigation, the Coda Q method is applied to a number of 94 local earthquakes with a magnitude between Ml=0.7 and Ml=4. The digital seismograms of these earthquakes were recorded during the year 2008 by both local temporary and permanent broadband seismic station network deployed in Northern of Morocco. The Q quality factor values have been computed at central frequencies 0.75, 1.5, 3, 6 and 12 Hz. The lapse time windows are restricted to 30s in order to sample the earth's crust only. The Q results indicate that strong frequency dependence follow a power law for the entire area. The preliminary results of seismic Coda Q attenuation tomography shows a dependence at each frequency band, between seismic attenuation and the geology structure units in the study area, especially in the region of Al Hoceima and the eastern part of the Rif which are characterized by high attenuation values due to active faults area, while low attenuation values are seen in the west and the south of the Rif in high frequencies.Peer Reviewe
A genome-wide association study for survival from a multi-centre European study identified variants associated with COVID-19 risk of death
Genome-wide association; Survival; COVID-19Asociación de todo el genoma; Supervivencia; COVID-19Associació de tot el genoma; Supervivència; COVID-19The clinical manifestations of SARS-CoV-2 infection vary widely among patients, from asymptomatic to life-threatening. Host genetics is one of the factors that contributes to this variability as previously reported by the COVID-19 Host Genetics Initiative (HGI), which identified sixteen loci associated with COVID-19 severity. Herein, we investigated the genetic determinants of COVID-19 mortality, by performing a case-only genome-wide survival analysis, 60 days after infection, of 3904 COVID-19 patients from the GEN-COVID and other European series (EGAS00001005304 study of the COVID-19 HGI). Using imputed genotype data, we carried out a survival analysis using the Cox model adjusted for age, age2, sex, series, time of infection, and the first ten principal components. We observed a genome-wide significant (P-value < 5.0 × 10−8) association of the rs117011822 variant, on chromosome 11, of rs7208524 on chromosome 17, approaching the genome-wide threshold (P-value = 5.19 × 10−8). A total of 113 variants were associated with survival at P-value < 1.0 × 10−5 and most of them regulated the expression of genes involved in immune response (e.g., CD300 and KLR genes), or in lung repair and function (e.g., FGF19 and CDH13). Overall, our results suggest that germline variants may modulate COVID-19 risk of death, possibly through the regulation of gene expression in immune response and lung function pathways.Istituto Buddista Italiano Soka Gakkai funded A.R.’s and F.C.’s project “PAT-COVID: Host genetics and pathogenetic mechanisms of COVID-19” with the 8 × 1000 funds (ID n. 2020-226 2016_RIC_3), that, in part, included the present study. We also thank the generous contribution of Banca Intesa San Paolo to R.A. The funding organisations had no role in design and conduct of the study; collection, management, analysis, and interpretation of the data; preparation, review, or approval of the manuscript
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