58 research outputs found
Stratospheric aerosols from the Sarychev volcano eruption in the 2009 Arctic summer
Aerosols from the Sarychev volcano eruption (Kuril Islands, northeast of Japan) were observed in the Arctic lower stratosphere a few days after the strongest SO2 injection which occurred on 15 and 16 June 2009. From the observations provided by the Infrared Atmospheric Sounding Interferometer (IASI) an estimated 0.9 Tg of sulphur dioxide was injected into the upper troposphere and lower stratosphere (UTLS). The resultant stratospheric sulphate aerosols were detected from satellites by the Optical Spectrograph and Infrared Imaging System (OSIRIS) limb sounder and by the Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) and from the surface by the Network for the Detection of Atmospheric Composition Changes (NDACC) lidar deployed at OHP (Observatoire de Haute-Provence, France). By the first week of July the aerosol plume had spread out over the entire Arctic region. The Sarychev-induced stratospheric aerosol over the Kiruna region (north of Sweden) was measured by the Stratospheric and Tropospheric Aerosol Counter (STAC) during eight balloon flights planned in August and September 2009. During this balloon campaign the Micro RadiomĂštre Ballon (MicroRADIBAL) and the Spectroscopie d'Absorption Lunaire pour l'Observation des Minoritaires Ozone et NOx (SALOMON) remote-sensing instruments also observed these aerosols. Aerosol concentrations returned to near-background levels by spring 2010. The effective radius, the surface area density (SAD), the aerosol extinction, and the total sulphur mass from STAC in situ measurements are enhanced with mean values in the range 0.15-0.21 ÎŒm, 5.5-14.7 ÎŒm2 cm-3, 5.5-29.5 Ă 10-4 km-1, and 4.9-12.6 Ă 10-10 kg[S] kg-1[air], respectively, between 14 km and 18 km. The observed and modelled e-folding time of sulphate aerosols from the Sarychev eruption is around 70-80 days, a value much shorter than the 12-14 months calculated for aerosols from the 1991 eruption of Mt Pinatubo. The OSIRIS stratospheric aerosol optical depth (AOD) at 750 nm is enhanced by a factor of 6, with a value of 0.02 in late July compared to 0.0035 before the eruption. The HadGEM2 and MIMOSA model outputs indicate that aerosol layers in polar region up to 14-15 km are largely modulated by stratosphere-troposphere exchange processes. The spatial extent of the Sarychev plume is well represented in the HadGEM2 model with lower altitudes of the plume being controlled by upper tropospheric troughs which displace the plume downward and upper altitudes around 18-20 km, in agreement with lidar observations. Good consistency is found between the HadGEM2 sulphur mass density and the value inferred from the STAC observations, with a maximum located about 1 km above the tropopause ranging from 1 to 2 Ă 10 -9 kg[S] kg-1[air], which is one order of magnitude higher than the background level. © Author(s) 2013.The authors thank the CNES balloon
launching team for successful operations and the Swedish Space
Corporation at Esrange. The ETHER database (CNES-INSUCNRS)
and the CNES âsous-direction Ballonâ are partners of the
project. The StraPolEt ÂŽ e project has been funded by the French ÂŽ
âAgence Nationale de la Rechercheâ (ANR-BLAN08-1-31627),
the âCentre National dâEtudes Spatialesâ (CNES), and the âInstitut ÂŽ
Polaire Paul-Emile Victorâ (IPEV). The AEROWAVE (Aerosols,
Water Vapor and Electricity) and the HALOHA (HALOgen in
High Altitudes) projects have been funded by the recently created
French CNES-INSU Balloon Committee (so-called CSTB). We are
grateful to Slimane Bekki and David Cugniet for their constructive
comments about the AER-UPMC 2-D model, to Marc-Antoine
Drouin for his help about the MIMOSA model, and to the LPC2E
technical team for this successful campaign. Jim Haywood and
Andy Jones were supported by the Joint DECC/Defra Met Office
Hadley Centre Climate Programme (GA01101). IASI was developed
and built under the responsibility of the Centre National
dâEtudes Spatiales (CNES, France). It is flown on board the Metop ÂŽ
satellites as part of the EUMETSAT Polar System. The IASI L1
data are received through the EUMETCast near-real-time data
distribution service. L. Clarisse is a postdoctoral researcher with
FRS-FNRS. We acknowledge the CALIOP team for acquiring
and processing data as well as the ICARE team for providing and
maintaining the computational facilities to store them. Odin is a
Swedish-led satellite project funded jointly by Sweden (SNSB),
Canada (CSA), France (CNES), and Finland (Tekes). This study
was supported by the French VOLTAIRE Labex (Laboratoire
dâExcellence ANR-10-LABX-100-01) managed by the University
of Orleans
Identification of four families of yCCR4- and Mg(2+)-dependent endonuclease-related proteins in higher eukaryotes, and characterization of orthologs of yCCR4 with a conserved leucine-rich repeat essential for hCAF1/hPOP2 binding
BACKGROUND: The yeast yCCR4 factor belongs to the CCR4-NOT transcriptional regulatory complex, in which it interacts, through its leucine-rich repeat (LRR) motif with yPOP2. Recently, yCCR4 was shown to be a component of the major cytoplasmic mRNA deadenylase complex, and to contain a fold related to the Mg(2+)-dependent endonuclease core. RESULTS: Here, we report the identification of nineteen yCCR4-related proteins in eukaryotes (including yeast, plants and animals), which all contain the yCCR4 endonuclease-like fold, with highly conserved CCR4-specific residues. Phylogenetic and genomic analyses show that they form four distinct families, one of which contains the yCCR4 orthologs. The orthologs in animals possess a leucine-rich repeat domain. We show, using two-hybrid and far-Western assays, that the human member binds to the human yPOP2 homologs, i.e. hCAF1 and hPOP2, in a LRR-dependent manner. CONCLUSIONS: We have identified the mammalian orthologs of yCCR4 and have shown that the human member binds to the human yPOP2 homologs, thus strongly suggesting conservation of the CCR4-NOT complex from yeast to human. All members of the four identified yCCR4-related protein families show stricking conservation of the endonuclease-like catalytic motifs of the yCCR4 C-terminal domain and therefore constitute a new family of potential deadenylases in mammals
Towards the prediction of essential genes by integration of network topology, cellular localization and biological process information
<p>Abstract</p> <p>Background</p> <p>The identification of essential genes is important for the understanding of the minimal requirements for cellular life and for practical purposes, such as drug design. However, the experimental techniques for essential genes discovery are labor-intensive and time-consuming. Considering these experimental constraints, a computational approach capable of accurately predicting essential genes would be of great value. We therefore present here a machine learning-based computational approach relying on network topological features, cellular localization and biological process information for prediction of essential genes.</p> <p>Results</p> <p>We constructed a decision tree-based meta-classifier and trained it on datasets with individual and grouped attributes-network topological features, cellular compartments and biological processes-to generate various predictors of essential genes. We showed that the predictors with better performances are those generated by datasets with integrated attributes. Using the predictor with all attributes, i.e., network topological features, cellular compartments and biological processes, we obtained the best predictor of essential genes that was then used to classify yeast genes with unknown essentiality status. Finally, we generated decision trees by training the J48 algorithm on datasets with all network topological features, cellular localization and biological process information to discover cellular rules for essentiality. We found that the number of protein physical interactions, the nuclear localization of proteins and the number of regulating transcription factors are the most important factors determining gene essentiality.</p> <p>Conclusion</p> <p>We were able to demonstrate that network topological features, cellular localization and biological process information are reliable predictors of essential genes. Moreover, by constructing decision trees based on these data, we could discover cellular rules governing essentiality.</p
The Jumonji-C oxygenase JMJD7 catalyzes (3S)-lysyl hydroxylation of TRAFAC GTPases
Biochemical, structural and cellular studies reveal Jumonji-C (JmjC) domain-containing 7 (JMJD7) to be a 2-oxoglutarate (2OG)-dependent oxygenase that catalyzes (3S)-lysyl hydroxylation. Crystallographic analyses reveal JMJD7 to be more closely related to the JmjC hydroxylases than to the JmjC demethylases. Biophysical and mutation studies show that JMJD7 has a unique dimerization mode, with interactions between monomers involving both N- and C-terminal regions and disulfide bond formation. A proteomic approach identifies two related members of the translation factor (TRAFAC) family of GTPases, developmentally regulated GTP-binding proteins 1 and 2 (DRG1/2), as activity-dependent JMJD7 interactors. Mass spectrometric analyses demonstrate that JMJD7 catalyzes Fe(ii)- and 2OG-dependent hydroxylation of a highly conserved lysine residue in DRG1/2; amino-acid analyses reveal that JMJD7 catalyzes (3S)-lysyl hydroxylation. The functional assignment of JMJD7 will enable future studies to define the role of DRG hydroxylation in cell growth and disease.Fil: Markolovic, Suzana. University of Oxford; Reino UnidoFil: Zhuang, Qinqin. University Of Birmingham; Reino UnidoFil: Wilkins, Sarah E.. University of Oxford; Reino UnidoFil: Eaton, Charlotte D.. University Of Birmingham; Reino UnidoFil: Abboud, Martine I.. University of Oxford; Reino UnidoFil: Katz, Maximiliano Javier. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Oficina de CoordinaciĂłn Administrativa Parque Centenario. Instituto de Investigaciones BioquĂmicas de Buenos Aires. FundaciĂłn Instituto Leloir. Instituto de Investigaciones BioquĂmicas de Buenos Aires; ArgentinaFil: McNeil, Helen E.. University Of Birmingham; Reino UnidoFil: LeĆniak, Robert K.. University of Oxford; Reino UnidoFil: Hall, Charlotte. University Of Birmingham; Reino UnidoFil: Struwe, Weston B.. University of Oxford; Reino UnidoFil: Konietzny, Rebecca. University of Oxford; Reino UnidoFil: Davis, Simon. University of Oxford; Reino UnidoFil: Yang, Ming. The Francis Crick Institute; Reino Unido. University of Oxford; Reino UnidoFil: Ge, Wei. University of Oxford; Reino UnidoFil: Benesch, Justin L. P.. University of Oxford; Reino UnidoFil: Kessler, Benedikt M.. University of Oxford; Reino UnidoFil: Ratcliffe, Peter J.. University of Oxford; Reino Unido. The Francis Crick Institute; Reino UnidoFil: Cockman, Matthew E.. The Francis Crick Institute; Reino Unido. University of Oxford; Reino UnidoFil: Fischer, Roman. University of Oxford; Reino UnidoFil: Wappner, Pablo. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Oficina de CoordinaciĂłn Administrativa Parque Centenario. Instituto de Investigaciones BioquĂmicas de Buenos Aires. FundaciĂłn Instituto Leloir. Instituto de Investigaciones BioquĂmicas de Buenos Aires; ArgentinaFil: Chowdhury, Rasheduzzaman. University of Stanford; Estados Unidos. University of Oxford; Reino UnidoFil: Coleman, Mathew L.. University Of Birmingham; Reino UnidoFil: Schofield, Christopher J.. University of Oxford; Reino Unid
Mutations in KEOPS-Complex Genes Cause Nephrotic Syndrome with Primary Microcephaly
Galloway-Mowat syndrome (GAMOS) is an autosomal-recessive disease characterized by the combination of early-onset nephrotic syndrome (SRNS) and microcephaly with brain anomalies. Here we identified recessive mutations in OSGEP, TP53RK, TPRKB, and LAGE3, genes encoding the four subunits of the KEOPS complex, in 37 individuals from 32 families with GAMOS. CRISPR-Cas9 knockout in zebrafish and mice recapitulated the human phenotype of primary microcephaly and resulted in early lethality. Knockdown of OSGEP, TP53RK, or TPRKB inhibited cell proliferation, which human mutations did not rescue. Furthermore, knockdown of these genes impaired protein translation, caused endoplasmic reticulum stress, activated DNA-damage-response signaling, and ultimately induced apoptosis. Knockdown of OSGEP or TP53RK induced defects in the actin cytoskeleton and decreased the migration rate of human podocytes, an established intermediate phenotype of SRNS. We thus identified four new monogenic causes of GAMOS, describe a link between KEOPS function and human disease, and delineate potential pathogenic mechanisms
The James Webb Space Telescope Mission
Twenty-six years ago a small committee report, building on earlier studies,
expounded a compelling and poetic vision for the future of astronomy, calling
for an infrared-optimized space telescope with an aperture of at least .
With the support of their governments in the US, Europe, and Canada, 20,000
people realized that vision as the James Webb Space Telescope. A
generation of astronomers will celebrate their accomplishments for the life of
the mission, potentially as long as 20 years, and beyond. This report and the
scientific discoveries that follow are extended thank-you notes to the 20,000
team members. The telescope is working perfectly, with much better image
quality than expected. In this and accompanying papers, we give a brief
history, describe the observatory, outline its objectives and current observing
program, and discuss the inventions and people who made it possible. We cite
detailed reports on the design and the measured performance on orbit.Comment: Accepted by PASP for the special issue on The James Webb Space
Telescope Overview, 29 pages, 4 figure
Qualification des émissions d'aérosols radioactifs liées à l'utilisation d'un générateur de technétium en service de médecine nucléaire
National audienceThe objective of this work is to characterize the emission of radioactive particles of 99mTc (technetium-99, a metastable gamma emitter of 6 h half-life) for lung marking in the environment of a nuclear medicine department. We studied the leakage of radioactive particles from the generating system during a lung scan test. This possible source of air contamination has been little studied and a specifically adapted survey methodology remains to be developed. To measure the leakage of radioactive particles from the generator, we designed a transportable test enclosure permitting one to collect and sample particles with a known accuracy, a low background level and the capability of recording short time events. Here, we present the characterization operations for this system and results we obtained with patients. The results show that radioactivity released in the air by the generator leakage is superior to that deposited in the patients' lungs by inhalation, that is, respectively, 5.7% and 3.8% of the total radioactivity initially introduced into the generator. © 2012 EDP Sciences.Lâobjectif de ce travail est de caractĂ©riser lâĂ©mission de particules radioactives de 99mTc (technĂ©tium-99 mĂ©tastable Ă©metteur gamma de demi-vie 6 h) servant au marquage pulmonaire dans lâenvironnement dâun service de mĂ©decine nuclĂ©aire. Nous avons Ă©tudiĂ© les fuites du systĂšme gĂ©nĂ©rateur de particules radioactives lors dâun examen de scintigraphie pulmonaire. Cette Ă©ventuelle source de contamination ambiante a Ă©tĂ© peu Ă©tudiĂ©e et une mĂ©thodologie de surveillance spĂ©cifiquement adaptĂ©e reste Ă dĂ©velopper. Pour mesurer les fuites des gĂ©nĂ©rateurs dâaĂ©rosols radioactifs Ă©tudiĂ©s, nous avons conçu une enceinte dâessai transportable permettant de capter les particules et de les Ă©chantillonner avec une prĂ©cision connue, un niveau de bruit de fond trĂšs faible et une capacitĂ© dâenregistrer les Ă©missions transitoires courtes. Nous prĂ©sentons les opĂ©rations de caractĂ©risation de ce systĂšme et les rĂ©sultats obtenus avec des patients. Ces rĂ©sultats montrent que lâactivitĂ© Ă©mise en ambiance par les fuites du gĂ©nĂ©rateur est supĂ©rieure Ă celle dĂ©posĂ©e dans les poumons du patient par inhalation, soit respectivement 5,7 % et 3,8 % de lâactivitĂ© initialement introduite dans le gĂ©nĂ©rateur
Qualification des Ă©missions dâaĂ©rosols radioactifs liĂ©es Ă lâutilisation dâun gĂ©nĂ©rateur de technĂ©tium en service de mĂ©decine nuclĂ©aire
The Mercantour/Alpi Marittime All Taxa Biodiversity Inventory (ATBI): achievements and prospects
Stratospheric aerosols from the Sarychev volcano eruption in the 2009 Arctic summer
Aerosols from the Sarychev volcano eruption (Kuril Islands, northeast of Japan) were observed in the Arctic lower stratosphere a few days after the strongest SO2 injection which occurred on 15 and 16 June 2009. From the observations provided by the Infrared Atmospheric Sounding Interferometer (IASI) an estimated 0.9 Tg of sulphur dioxide was injected into the upper troposphere and lower stratosphere (UTLS). The resultant stratospheric sulphate aerosols were detected from satellites by the Optical Spectrograph and Infrared Imaging System (OSIRIS) limb sounder and by the Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) and from the surface by the Network for the Detection of Atmospheric Composition Changes (NDACC) lidar deployed at OHP (Observatoire de Haute-Provence, France). By the first week of July the aerosol plume had spread out over the entire Arctic region. The Sarychev-induced stratospheric aerosol over the Kiruna region (north of Sweden) was measured by the Stratospheric and Tropospheric Aerosol Counter (STAC) during eight balloon flights planned in August and September 2009. During this balloon campaign the Micro RadiomĂštre Ballon (MicroRADIBAL) and the Spectroscopie d'Absorption Lunaire pour l'Observation des Minoritaires Ozone et NOx (SALOMON) remote-sensing instruments also observed these aerosols. Aerosol concentrations returned to near-background levels by spring 2010. The effective radius, the surface area density (SAD), the aerosol extinction, and the total sulphur mass from STAC in situ measurements are enhanced with mean values in the range 0.15-0.21 ÎŒm, 5.5-14.7 ÎŒm2 cm-3, 5.5-29.5 Ă 10-4 km-1, and 4.9-12.6 Ă 10-10 kg[S] kg-1[air], respectively, between 14 km and 18 km. The observed and modelled e-folding time of sulphate aerosols from the Sarychev eruption is around 70-80 days, a value much shorter than the 12-14 months calculated for aerosols from the 1991 eruption of Mt Pinatubo. The OSIRIS stratospheric aerosol optical depth (AOD) at 750 nm is enhanced by a factor of 6, with a value of 0.02 in late July compared to 0.0035 before the eruption. The HadGEM2 and MIMOSA model outputs indicate that aerosol layers in polar region up to 14-15 km are largely modulated by stratosphere-troposphere exchange processes. The spatial extent of the Sarychev plume is well represented in the HadGEM2 model with lower altitudes of the plume being controlled by upper tropospheric troughs which displace the plume downward and upper altitudes around 18-20 km, in agreement with lidar observations. Good consistency is found between the HadGEM2 sulphur mass density and the value inferred from the STAC observations, with a maximum located about 1 km above the tropopause ranging from 1 to 2 Ă 10 -9 kg[S] kg-1[air], which is one order of magnitude higher than the background level. © Author(s) 2013.SCOPUS: ar.jinfo:eu-repo/semantics/publishe
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