Conformational plasticity of RepB, the replication initiator protein of promiscuous streptococcal plasmid pMV158

13 p.-7 fig.-1 tab.DNA replication initiation is a vital and tightly regulated step in all replicons and requires an initiator factor that specifically recognizes the DNA replication origin and starts replication. RepB from the promiscuous streptococcal plasmid pMV158 is a hexameric ring protein evolutionary related to viral initiators. Here we explore the conformational plasticity of the RepB hexamer by i) SAXS, ii)sedimentation experiments, iii) molecular simulations and iv) X-ray crystallography. Combining these techniques, we derive an estimate of the conformational ensemble in solution showing that the C-terminal oligomerisation domains of the protein form a rigid cylindrical scaffold to which the N-terminal DNA-binding/catalytic domains are attached as highly flexible appendages, featuring multiple orientations. In addition, we show that the hinge region connecting both domains plays a pivotal role in the observed plasticity. Sequence comparisons and a literature survey show that this hinge region could exists in other initiators, suggesting that it is a common, crucial structural element for DNA binding and manipulation.This study was supported by the Ministerio de Economía y Competitividad (Grants BFU2008-02372/BMC; BFU2011-22588, BFU2014-53550 and Unidad de Excelencia Maria de Maeztu MDM-2014-0435 to MC; BIO2009-10964 and E-SCIENCE to MO;BFU2010-19597, PNEUMOTALK, and CSD2008-00013, INTERMODS, to GdS; Ramón and Cajal subprogramme RYC-2011-09071 to CM), the Generalitat de Catalunya (Grants 2014-SGR1309 to MC and SGR2009-1348 to MO),Fundación Marcelino Botín (MO) and the European Commission (Cooperation Project SILVER, GA No. 260644 to MC and SCALALIFE Project to MO).Peer reviewe

Cáncer pulmonar: prevención y pesquisa precoz

ResumenEl cáncer pulmonar es el más mortal de todos los cánceres. Debido a que la gran mayoría de los cánceres pulmonares son causados por el hábito de fumar, su erradicación es la mejor estrategia de prevención primaria. El diagnóstico del cáncer pulmonar en etapas tempranas mejora significativamente su pronóstico, por lo que ésta es la mejor estrategia de prevención secundaria. Recientemente se ha reportado que un programa de pesquisa de cáncer pulmonar con escáner de tórax (TAC) reduce la mortalidad por cáncer. El objetivo de esta revisión es, en primer lugar, apelar a la evidencia en cuanto al rendimiento de los programas de pesquisa de cáncer pulmonar en poblaciones de alto riesgo, y en segundo lugar, analizar las distintas estrategias que tiene un médico cuando se enfrenta a un paciente a quien se le ha encontrado incidentalmente un nódulo pulmonar.SummaryLung cancer is a deadly disease. Since this cancer is closely related to tobacco smoke, the best way to avoid this disease is smoking prevention. Unfortunately smoking is a worldwide epidemic and in Chile its prevalence is not decreasing. The second best strategy is an early detection. For the first time there is a report showing that screening with the use of low-dose CT reduces mortality from lung cancer. The prognosis is much better in early stages. The purpose of this publication is to review the evidence about screening of lung cancer, and to analyze the different strategies to deal, in the general practice, with a finding of a lung nodule

Outbreak of persistent cutaneous abscesses due to Mycobacterium chelonae after mesotherapy sessions, Lima, Peru

Surtos de micobactérias de crescimento rápido têm sido relatados ocasionalmente. O estudo relata um surto de abscessos cutâneos por Mycobacterium chelonae após sessões de mesoterapia em Lima, Peru. De dezembro de 2004 a janeiro de 2005, 35 pessoas que haviam passado por sessões de mesoterapia apresentaram esses abscessos cutâneos. Treze (37%) desses casos suspeitos concordaram em realizar exames clínicos. Foram realizadas biópsias de punção de pele de lesões suspeitas e examinadas substâncias injetadas durante a mesoterapia. Os casos suspeitos eram predominantemente mulheres jovens e as lesões incluíram nódulos subcutâneos, abscessos e úlceras. Mycobacterium chelonae foi isolada de quatro pacientes e de um frasco de procaína. Em conclusão, é importante considerar a mesoterapia como fonte potencial de infecções de micobactérias de crescimento rápido.Outbreaks of rapidly growing mycobacteria have been occasionally described. The article reports an outbreak of cutaneous abscesses due to Mycobacterium chelonae following mesotherapy in Lima, Peru. From December 2004 through January 2005, 35 subjects who had participated in mesotherapy training sessions presented with persistent cutaneous abscesses. Thirteen (37%) of these suspected cases consented to underwent clinical examination. Skin punch-biopsies were collected from suspicious lesions and substances injected during mesotherapy were analyzed. Suspected cases were mainly young women and lesions included subcutaneous nodules, abscesses and ulcers. Mycobacterium chelonae was isolated from four patients and from a procaine vial. In conclusion, it is important to consider mesotherapy as a potential source of rapidly growing mycobacteria infections

Engineering of III-Nitride Semiconductors on Low Temperature Co-fired Ceramics

This work presents results in the feld of advanced substrate solutions in order to achieve high crystalline quality group-III nitrides based heterostructures for high frequency and power devices or for sensor applications. With that objective, Low Temperature Co-fred Ceramics has been used, as a noncrystalline substrate. Structures like these have never been developed before, and for economic reasons will represent a groundbreaking material in these felds of Electronic. In this sense, the report presents the characterization through various techniques of three series of specimens where GaN was deposited on this ceramic composite, using diferent bufer layers, and a singular metal-organic chemical vapor deposition related technique for low temperature deposition. Other single crystalline ceramic-based templates were also utilized as substrate materials, for comparison purposes

Single hadron response measurement and calorimeter jet energy scale uncertainty with the ATLAS detector at the LHC

The uncertainty on the calorimeter energy response to jets of particles is derived for the ATLAS experiment at the Large Hadron Collider (LHC). First, the calorimeter response to single isolated charged hadrons is measured and compared to the Monte Carlo simulation using proton-proton collisions at centre-of-mass energies of sqrt(s) = 900 GeV and 7 TeV collected during 2009 and 2010. Then, using the decay of K_s and Lambda particles, the calorimeter response to specific types of particles (positively and negatively charged pions, protons, and anti-protons) is measured and compared to the Monte Carlo predictions. Finally, the jet energy scale uncertainty is determined by propagating the response uncertainty for single charged and neutral particles to jets. The response uncertainty is 2-5% for central isolated hadrons and 1-3% for the final calorimeter jet energy scale.Comment: 24 pages plus author list (36 pages total), 23 figures, 1 table, submitted to European Physical Journal

Standalone vertex finding in the ATLAS muon spectrometer

A dedicated reconstruction algorithm to find decay vertices in the ATLAS muon spectrometer is presented. The algorithm searches the region just upstream of or inside the muon spectrometer volume for multi-particle vertices that originate from the decay of particles with long decay paths. The performance of the algorithm is evaluated using both a sample of simulated Higgs boson events, in which the Higgs boson decays to long-lived neutral particles that in turn decay to bbar b final states, and pp collision data at √s = 7 TeV collected with the ATLAS detector at the LHC during 2011

Measurements of Higgs boson production and couplings in diboson final states with the ATLAS detector at the LHC

Measurements are presented of production properties and couplings of the recently discovered Higgs boson using the decays into boson pairs, H →γ γ, H → Z Z∗ →4l and H →W W∗ →lνlν. The results are based on the complete pp collision data sample recorded by the ATLAS experiment at the CERN Large Hadron Collider at centre-of-mass energies of √s = 7 TeV and √s = 8 TeV, corresponding to an integrated luminosity of about 25 fb−1. Evidence for Higgs boson production through vector-boson fusion is reported. Results of combined fits probing Higgs boson couplings to fermions and bosons, as well as anomalous contributions to loop-induced production and decay modes, are presented. All measurements are consistent with expectations for the Standard Model Higgs boson

Expected Performance of the ATLAS Experiment - Detector, Trigger and Physics

A detailed study is presented of the expected performance of the ATLAS detector. The reconstruction of tracks, leptons, photons, missing energy and jets is investigated, together with the performance of b-tagging and the trigger. The physics potential for a variety of interesting physics processes, within the Standard Model and beyond, is examined. The study comprises a series of notes based on simulations of the detector and physics processes, with particular emphasis given to the data expected from the first years of operation of the LHC at CERN

Measurement of the top quark-pair production cross section with ATLAS in pp collisions at \sqrt{s}=7\TeV

A measurement of the production cross-section for top quark pairs(\ttbar) in $pp$ collisions at \sqrt{s}=7 \TeV is presented using data recorded with the ATLAS detector at the Large Hadron Collider. Events are selected in two different topologies: single lepton (electron $e$ or muon $\mu$) with large missing transverse energy and at least four jets, and dilepton ($ee$, $\mu\mu$ or $e\mu$) with large missing transverse energy and at least two jets. In a data sample of 2.9 pb-1, 37 candidate events are observed in the single-lepton topology and 9 events in the dilepton topology. The corresponding expected backgrounds from non-\ttbar Standard Model processes are estimated using data-driven methods and determined to be $12.2 \pm 3.9$ events and $2.5 \pm 0.6$ events, respectively. The kinematic properties of the selected events are consistent with SM \ttbar production. The inclusive top quark pair production cross-section is measured to be \sigmattbar=145 \pm 31 ^{+42}_{-27} pb where the first uncertainty is statistical and the second systematic. The measurement agrees with perturbative QCD calculations.Comment: 30 pages plus author list (50 pages total), 9 figures, 11 tables, CERN-PH number and final journal adde

Measurement of the top quark pair cross section with ATLAS in pp collisions at √s=7 TeV using final states with an electron or a muon and a hadronically decaying τ lepton

A measurement of the cross section of top quark pair production in proton-proton collisions recorded with the ATLAS detector at the Large Hadron Collider at a centre-of-mass energy of 7 TeV is reported. The data sample used corresponds to an integrated luminosity of 2.05 fb -1. Events with an isolated electron or muon and a τ lepton decaying hadronically are used. In addition, a large missing transverse momentum and two or more energetic jets are required. At least one of the jets must be identified as originating from a b quark. The measured cross section, σtt-=186±13(stat.)±20(syst.)±7(lumi.) pb, is in good agreement with the Standard Model prediction