226 research outputs found

    Differential multimerization of Moloney murine leukemia virus integrase purified under nondenaturing conditions

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    Retroviral integrases (IN) catalyze the integration of the reverse-transcribed viral DNA into the host genome, an essential process leading to virus replication. For Moloney murine leukemia virus (M-MuLV) IN, the limited solubility of the recombinant protein has restricted the development of biophysical and structural analyses. Herein, recombinant M-MuLV IN proteins, either full length or two nonoverlapping domain constructs, were purified under non-denaturing conditions from solubilized bacterial extracts by Ni2+-NTA resins. Additionally, WT IN was further purified by heparin chromatography. All of the purified proteins were shown to be active and stable. WT M-MuLV IN chromatographed with a peak corresponding with a dimer by gel filtration chromatography. In contrast, the single point mutant C209A IN migrated predominantly as a tetramer. For both proteins, fractions in equilibrium between dimers and tetramers were competent to assemble concerted two-end integrations and yielded a unique strand-transfer profile in the presence of a 28-mer U5 oligonucleotide substrate, indicative of a distinct conformation within the synaptic complex. This specific target-site selection was not observed with a shorter 20-mer U5 substrate. These studies provide the foundation for biophysical and structural analysis on M-MuLV IN and the mechanism of retroviral integration

    Inhibition of Moloney murine leukemia virus integration using polyamides targeting the long-terminal repeat sequences

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    The retroviral integrase (IN) carries out the integration of the viral DNA into the host genome. Both IN and the DNA sequences at the viral long-terminal repeat (LTR) are required for the integration function. In this report, a series of minor groove binding hairpin polyamides targeting sequences within terminal inverted repeats of the Moloney murine leukemia virus (M-MuLV) LTR were synthesized, and their effects on integration were analyzed. Using cell-free in vitro integration assays, polyamides targeting the conserved CA dinucleotide with cognate sites closest to the terminal base pairs were effective at blocking 3' processing but not strand transfer. Polyamides which efficiently inhibited 3' processing and strand transfer targeted the LTR sequences through position 9. Polyamides that inhibited integration were effective at nanomolar concentrations and showed subnanomolar affinity for their cognate LTR sites. These studies highlight the role of minor groove interactions within the LTR termini for retroviral integration

    Perfil bioquĂ­mico renal en cuyes (Cavia porcellus) alimentados con pisonay (Erythrina sp)

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    The experiment was carried out in the district of Tamburco, province of Abancay, Peru, between January and April 2017 and aimed to determine serum levels of creatinine, urea and blood urea nitrogen (BUN) in guinea pigs fed with pisonay (Erythrina sp). Leaves and petioles of pisonay with four months of regrowth and fresh alfalfa (Medicago sativa) with 28 days of regrowth were used in the diet of 18 improved male guinea pigs. The animals were distributed in three treatments: A100: 100% alfalfa (80 g), A50P50: 50% alfalfa (40 g) plus 50% pisonay (40 g) and P100: 100% pisonay (80 g). The feed was provided twice a day. Serum creatinine levels in guinea pigs fed A50P50 and P100 were significantly higher compared to those that consumed A100 (p<0.05). The BUN levels were only significantly different between A100 and P100 (p<0.05), while there were no significant differences between treatments for the case of blood urea. The proportional increase of 50 to 100% of pisonay leaves as fresh forage in the diet of guinea pigs could cause disorders in kidney function.El experimento se realizĂł en el distrito de Tamburco, provincia de Abancay, PerĂş, entre enero y abril de 2017 y tuvo como objetivo determinar los niveles sĂŠricos de creatinina, urea y nitrĂłgeno ureico en sangre (BUN) en cuyes alimentados con pisonay (Erythrina sp). Se utilizaron hojas y peciolos de pisonay con cuatro meses de rebrote y alfalfa fresca (Medicago sativa) con 28 dĂ­as de rebrote en la dieta de 18 cuyes machos mejorados. Los animales fueron distribuidos en tres tratamientos: A100, 100% de alfalfa (80 g), A50P50, 50% alfalfa (40 g) mĂĄs 50% de pisonay (40 g) y P100: 100% de pisonay (80 g). El alimento fue proporcionado dos veces al dĂ­a. Los niveles sĂŠricos de creatinina en cuyes alimentados con A50P50 y P100 fueron significativamente mayores con respecto a los que consumieron A100 (p<0.05). Los niveles de BUN solo fueron significativamente diferentes entre A100 y P100 (p<0.05), mientras que no hubo diferencias significativas entre tratamientos para el caso de la urea sanguĂ­nea. El incremento proporcional de 50 a 100% de hojas de pisonay como forraje fresco en la dieta de cuyes podrĂ­a provocar trastornos en la funciĂłn renal

    Inhibition of Moloney murine leukemia virus integration using polyamides targeting the long-terminal repeat sequences

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    The retroviral integrase (IN) carries out the integration of the viral DNA into the host genome. Both IN and the DNA sequences at the viral long-terminal repeat (LTR) are required for the integration function. In this report, a series of minor groove binding hairpin polyamides targeting sequences within terminal inverted repeats of the Moloney murine leukemia virus (M-MuLV) LTR were synthesized, and their effects on integration were analyzed. Using cell-free in vitro integration assays, polyamides targeting the conserved CA dinucleotide with cognate sites closest to the terminal base pairs were effective at blocking 3' processing but not strand transfer. Polyamides which efficiently inhibited 3' processing and strand transfer targeted the LTR sequences through position 9. Polyamides that inhibited integration were effective at nanomolar concentrations and showed subnanomolar affinity for their cognate LTR sites. These studies highlight the role of minor groove interactions within the LTR termini for retroviral integration

    Sex and Age Morphometric Variations in Bony Nasolacrimal Duct and Fossa for Lacrimal Gland in Mexican Population

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    SUMMARY: Primary acquired nasolacrimal duct obstruction is greater in women over 40 years and has been associated with morphometric variations in the osseous nasolacrimal duct, which varies according to age and sex. The objective is to determine variations regarding sex and age of the nasolacrimal duct and osseous fossa for lacrimal gland. One hundred sixteen dry orbits from Mexican population were analyzed; subdivided into four groups based on age and sex. The length, transverse and anteroposterior diameters of the bone entrance of the nasolacrimal duct, and the length and width of the fossa for lacrimal gland were determined. Statistical tests were applied to determine the significance of the differences found between groups. The nasolacrimal duct in women had shorter length than men in both age groups. The entrance had a wider transverse diameter in women than men independently of age and its anteroposterior diameter was shorter in men under 40 years than over 40 years. The fossa for lacrimal gland was larger in women under 40 years than in men of same age group and women over 40 years old. The lower third of the was wider in women under 40 years than in women over 40 years. Our study confirms significant differences between sex and age groups in some of the morphometric measurements of bony nasolacrimal duct and fossa for lacrimal gland in Mexican population. Comparative studies with and without clinical illness are needed to clarify if the bony characteristics of those structures participate in the etiopathogenesis and distribution differences observed in sex, age and ethnicity of thisillness. KEY WORDS: Nasolacrimal duct; Fossa for lacrimal gland; Morphometry; Primary acquired nasolacrimal duct obstructio

    Tuning the Magnetic Response of Magnetospirillum magneticum by Changing the Culture Medium A Straightforward Approach to Improve Their Hyperthermia Efficiency

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    Magnetotactic bacteria Magnetospirillum magneticum AMB 1 have been cultured using three different media magnetic spirillum growth medium with Wolfe s mineral solution MSGM W , magnetic spirillum growth medium without Wolfe s mineral solution MSGM W , and flask standard medium FSM . The influence of the culture medium on the structural, morphological, and magnetic characteristics of the magnetosome chains biosynthesized by these bacteria has been investigated by using transmission electron microscopy, X ray absorption spectroscopy, and X ray magnetic circular dichroism. All bacteria exhibit similar average size for magnetosomes, 40 45 nm, but FSM bacteria present slightly longer subchains. In MSGM W bacteria, Co2 ions present in the medium substitute Fe2 ions in octahedral positions with a total Co doping around 4 5 . In addition, the magnetic response of these bacteria has been thoroughly studied as functions of both the temperature and the applied magnetic field. While MSGM W and FSM bacteria exhibit similar magnetic behavior, in the case of MSGM W, the incorporation of the Co ions affects the magnetic response, in particular suppressing the Verwey amp; 8764;105 K and low temperature amp; 8764;40 K transitions and increasing the coercivity and remanence. Moreover, simulations based on a Stoner Wolhfarth model have allowed us to reproduce the experimentally obtained magnetization versus magnetic field loops, revealing clear changes in different anisotropy contributions for these bacteria depending on the employed culture medium. Finally, we have related how these magnetic changes affect their heating efficiency by using AC magnetometric measurements. The obtained AC hysteresis loops, measured with an AC magnetic field amplitude of up to 90 mT and a frequency, f, of 149 kHz, reveal the influence of the culture medium on the heating properties of these bacteria below 35 mT, MSGM W bacteria are the best heating mediators, but above 60 mT, FSM and MSGM W bacteria give the best heating results, reaching a maximum heating efficiency or specific absorption rate SAR of SAR f amp; 8776; 12 W g 1 kHz

    Performance and Operation of the CMS Electromagnetic Calorimeter

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    The operation and general performance of the CMS electromagnetic calorimeter using cosmic-ray muons are described. These muons were recorded after the closure of the CMS detector in late 2008. The calorimeter is made of lead tungstate crystals and the overall status of the 75848 channels corresponding to the barrel and endcap detectors is reported. The stability of crucial operational parameters, such as high voltage, temperature and electronic noise, is summarised and the performance of the light monitoring system is presented

    Trends in incidence and outcomes of revision total hip arthroplasty in Spain: A population based study

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    <p>Abstract</p> <p>Background</p> <p>To analyze changes in incidence and outcomes of patients undergoing revision total hip arthroplasty (RTHA) over an 8-year study period in Spain.</p> <p>Methods</p> <p>We selected all surgical admissions in individuals aged ≥ 40 years who underwent RTHA (ICD-9-CM procedure code 81.53) between 2001 and 2008 from the Spanish National Hospital Discharge Database. Age- and sex-specific incidence rates, Charlson co-morbidity index, length of stay (LOS), costs and in-hospital mortality (IHM) were estimated for each year. Multivariate analyses were conducted to asses time trends.</p> <p>Results</p> <p>32, 280 discharges of patients (13, 391 men/18, 889 women) having undergone RTHA were identified. Overall crude incidence showed a small but significant increase from 20.2 to 21.8 RTHA per 100, 000 inhabitants from 2001 to 2008 (p < 0.01).</p> <p>The incidence increased for men (17.7 to 19.8 in 2008) but did not vary for women (22.3 in 2001 and 22.2 in 2008). Greater increments were observed in patients older than 84 years and in the age group 75-84. In 2001, 19% of RTHA patients had a Charlson Index ≥ 1 and this proportion rose to 24.6% in 2008 (p < 0.001). The ratio RTHA/THA remained stable and around 20% in Spain along the entire period</p> <p>The crude overall in-hospital mortality (IHM) increased from 1.16% in 2001 to 1.77% (p = 0.025) in 2008. For both sexes the risk of death was higher with age, with the highest mortality rates found among those aged 85 or over. After multivariate analysis no change was observed in IHM over time. The mean inflation adjusted cost per patient increased by 78.3%, from 9, 375 to 16, 715 Euros from 2001 to 2008.</p> <p>After controlling for possible confounders using Poisson regression models, we observed that the incidence of RTHA hospitalizations significantly increased for men and women over the period 2001 to 2008 (IRR 1.10, 95% CI 1.03-1.18 and 1.08, 95% CI 1.02-1.14 respectively).</p> <p>Conclusions</p> <p>The crude incidence of RTHA in Spain showed a small but significant increase from 2001 to 2008 with concomitant reductions in LOS, significant increase in co-morbidities and cost per patient.</p

    Expected Performances of the NOMAD/ExoMars instrument

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    NOMAD (Nadir and Occultation for MArs Discovery) is one of the four instruments on board the ExoMars Trace Gas Orbiter, scheduled for launch in March 2016. It consists of a suite of three high-resolution spectrometers – SO (Solar Occultation), LNO (Limb, Nadir and Occultation) and UVIS (Ultraviolet and Visible Spectrometer). Based upon the characteristics of the channels and the values of Signal-to-Noise Ratio obtained from radiometric models discussed in [Vandaele et al., Optics Express, 2015] and [Thomas et al., Optics Express, 2015], the expected performances of the instrument in terms of sensitivity to detection have been investigated. The analysis led to the determination of detection limits for 18 molecules, namely CO, H2O, HDO, C2H2, C2H4, C2H6, H2CO, CH4, SO2, H2S, HCl, HCN, HO2, NH3, N2O, NO2, OCS, O3. NOMAD should have the ability to measure methane concentrations <25 parts per trillion (ppt) in solar occultation mode, and 11 parts per billion in nadir mode. Occultation detections as low as 10 ppt could be made if spectra are averaged [Drummond et al., Planetary Space and Science, 2011]. Results have been obtained for all three channels in nadir and in solar occultation
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