546 research outputs found

    The Mode of Death of Pig Kidney Cells Infected with Cowpox Virus Is Governed by the Expression of thecrmAGene

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    AbstractPig kidney cells (LLC-PK1) were infected with one of three viruses: wild-type cowpox virus (Brighton red strain) expressing thecrmAgene; recombinant cowpox virus A602, lacking thecrmAgene; or cowpox virus A604, a revertant of virus A602, expressing thecrmAgene. The wild-type virus and virus A604 produced identical cytopathic effects consistent with death by necrosis. In these cells, the structural features of the plasma membrane, the nuclear membrane, and the chromatin were maintained until lysis of the cells. In contrast, cowpox virus A602 produced cytopathic effects consistent with death by apoptosis. These effects included loss of microvilli on the cell surface, margination and condensation of the chromatin, progressive convolution of the nuclear membrane, release of dense chromatin masses on disintegration of the nucleus, fragmentation of the DNA, and the generation of apoptotic bodies. These results suggest that thecrmAgene is necessary to inhibit processes of apoptosis induced in LLC-PK1cells by infection with cowpox virus. Thus in cells of certain types, thecrmAgene can act with other viral genes to control the mode of death of the virus-infected cell. This capability may be advantageous to virus replicationin vivo,potentially facilitating both virus trafficking and interference with antiviral immune defenses

    A 43-Nucleotide RNACis-Acting Element Governs the Site-Specific Formation of the 3′ End of a Poxvirus Late mRNA

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    AbstractThe 3′ ends of late mRNAs of theatigene, encoding the major component of the A-type inclusions, are generated by endoribonucleolytic cleavage at a specific site in the primary transcript [Antczaket al.,(1992),Proc. Natl. Acad. Sci. USA89, 12033–12037]. In this study, sequence analysis of cDNAs of the 3′ ends ofatimRNAs showed these mRNAs are 3′ polyadenylated at the RNA cleavage site. This suggests thatatimRNA 3′ end formation involves cleavage of a late transcript, with subsequent 3′ polyadenylation of the 5′ cleavage product. The RNAcis-acting element, the AX element, directing orientation-dependent formation of these mRNA 3′ ends, was mapped to a 345-bpAluI–XbaI fragment. Deletion analyses of this fragment showed that the boundaries of the AX element are within −5 and +38 of the RNA cleavage site. Scanning mutagenesis showed that the AX element contains at least two subelements: subelement I, 5′-UUUAU↓CCGAUAAUUC-3′, containing the cleavage site (↓), separated from the downstream subelement II, 5′-AAUUUCGGAUUUGAAUGC-3′, by a 10-nucleotide region, whose composition may be altered without effect on RNA 3′ end formation. These features, which differ from those of other elements controlling RNA processing, suggest that the AX element is a component of a novel mechanism of RNA 3′ end formation

    Effect of local environment and stellar mass on galaxy quenching and morphology at 0.5<z<2.00.5<z<2.0

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    We study galactic star-formation activity as a function of environment and stellar mass over 0.5<z<2.0 using the FourStar Galaxy Evolution (ZFOURGE) survey. We estimate the galaxy environment using a Bayesian-motivated measure of the distance to the third nearest neighbor for galaxies to the stellar mass completeness of our survey, log(M/M)>9(9.5)\log(M/M_\odot)>9 (9.5) at z=1.3 (2.0). This method, when applied to a mock catalog with the photometric-redshift precision (σz/(1+z)0.02\sigma_z / (1+z) \lesssim 0.02), recovers galaxies in low- and high-density environments accurately. We quantify the environmental quenching efficiency, and show that at z> 0.5 it depends on galaxy stellar mass, demonstrating that the effects of quenching related to (stellar) mass and environment are not separable. In high-density environments, the mass and environmental quenching efficiencies are comparable for massive galaxies (log(M/M)\log (M/M_\odot)\gtrsim 10.5) at all redshifts. For lower mass galaxies (log(M/M))\log (M/M)_\odot) \lesssim 10), the environmental quenching efficiency is very low at zz\gtrsim 1.5, but increases rapidly with decreasing redshift. Environmental quenching can account for nearly all quiescent lower mass galaxies (log(M/M)\log(M/M_\odot) \sim 9-10), which appear primarily at zz\lesssim 1.0. The morphologies of lower mass quiescent galaxies are inconsistent with those expected of recently quenched star-forming galaxies. Some environmental process must transform the morphologies on similar timescales as the environmental quenching itself. The evolution of the environmental quenching favors models that combine gas starvation (as galaxies become satellites) with gas exhaustion through star-formation and outflows ("overconsumption"), and additional processes such as galaxy interactions, tidal stripping and disk fading to account for the morphological differences between the quiescent and star-forming galaxy populations.Comment: 29 pages, 15 figure, accepted for publication in Ap

    fMRI evidence of ‘mirror’ responses to geometric shapes

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    Mirror neurons may be a genetic adaptation for social interaction [1]. Alternatively, the associative hypothesis [2], [3] proposes that the development of mirror neurons is driven by sensorimotor learning, and that, given suitable experience, mirror neurons will respond to any stimulus. This hypothesis was tested using fMRI adaptation to index populations of cells with mirror properties. After sensorimotor training, where geometric shapes were paired with hand actions, BOLD response was measured while human participants experienced runs of events in which shape observation alternated with action execution or observation. Adaptation from shapes to action execution, and critically, observation, occurred in ventral premotor cortex (PMv) and inferior parietal lobule (IPL). Adaptation from shapes to execution indicates that neuronal populations responding to the shapes had motor properties, while adaptation to observation demonstrates that these populations had mirror properties. These results indicate that sensorimotor training induced populations of cells with mirror properties in PMv and IPL to respond to the observation of arbitrary shapes. They suggest that the mirror system has not been shaped by evolution to respond in a mirror fashion to biological actions; instead, its development is mediated by stimulus-general processes of learning within a system adapted for visuomotor control

    Genomic characterization of novel Neisseria species

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    Abstract: Of the ten human-restricted Neisseria species two, Neisseria meningitidis, and Neisseria gonorrhoeae, cause invasive disease: the other eight are carried asymptomatically in the pharynx, possibly modulating meningococcal and gonococcal infections. Consequently, characterizing their diversity is important for understanding the microbiome in health and disease. Whole genome sequences from 181 Neisseria isolates were examined, including those of three well-defined species (N. meningitidis; N. gonorrhoeae; and Neisseria polysaccharea) and genomes of isolates unassigned to any species (Nspp). Sequence analysis of ribosomal genes, and a set of core (cgMLST) genes were used to infer phylogenetic relationships. Average Nucleotide Identity (ANI) and phenotypic data were used to define species clusters, and morphological and metabolic differences among them. Phylogenetic analyses identified two polyphyletic clusters (N. polysaccharea and Nspp.), while, cgMLST data grouped Nspp isolates into nine clusters and identified at least three N. polysaccharea clusters. ANI results classified Nspp into seven putative species, and also indicated at least three putative N. polysaccharea species. Electron microscopy identified morphological differences among these species. This genomic approach provided a consistent methodology for species characterization using distinct phylogenetic clusters. Seven putative novel Neisseria species were identified, confirming the importance of genomic studies in the characterization of the genus Neisseria

    Vaccination with Venezuelan equine encephalitis replicons encoding cowpox virus structural proteins protects mice from intranasal cowpox virus challenge

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    An anti-poxvirus vaccine based on replicon particles of Venezuelan equine encephalitis virus (VRP) is being developed. The cowpox virus genes encoding structural proteins corresponding to vaccinia virus proteins A33, B5, and A27 were each expressed from VRP. High serum IgG titers against these proteins were generated in BALB/c mice vaccinated with each of these VRP. VRP induced both IgG1 and IgG2a with a strong predominance of IgG2a production. The response is long-lasting, as evidenced by the retention of high anti-B5 serum IgG titers through at least 50 weeks after priming immunization. Mice vaccinated with B5-, A33- or A27-VRP individually or together survived intranasal challenge with cowpox virus, with the multivalent vaccine formulation providing more effective protection from weight loss and clinical signs of illness than the monovalent vaccines. These results demonstrate that VRP may provide an effective alternative to vaccinia virus vaccines against poxvirus infection

    Angiotensin-(1-7) and angiotensin-(1-9): function in cardiac and vascular remodeling

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    The renin angiotensin system (RAS) is integral to cardiovascular physiology, however, dysregulation of this system largely contributes to the pathophysiology of cardiovascular disease (CVD). It is well established that angiotensin II (Ang II), the main effector of the RAS, engages the angiotensin type 1 receptor and promotes cell growth, proliferation, migration and oxidative stress, all processes which contribute to remodeling of the heart and vasculature, ultimately leading to the development and progression of various CVDs including heart failure and atherosclerosis. The counter-regulatory axis of the RAS, which is centered on the actions of angiotensin converting enzyme 2 (ACE2) and the resultant production of angiotensin-(1-7) (Ang-(1-7) from Ang II, antagonizes the actions of Ang II via the receptor Mas, thereby providing a protective role in CVD. More recently, another ACE2 metabolite, Ang-(1-9), has been reported to be a biologically active peptide within the counter-regulatory axis of the RAS. This review will discuss the role of the counter-regulatory RAS peptides, Ang-(1-7) and Ang-(1-9) in the cardiovascular system, with a focus on their effects in remodeling of the heart and vasculature

    Characterizing the Near-infrared Spectra of Flares from TRAPPIST-1 During JWST Transit Spectroscopy Observations

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    We present the first analysis of JWST near-infrared spectroscopy of stellar flares from TRAPPIST-1 during transits of rocky exoplanets. Four flares were observed from 0.6--2.8 μ\mum with NIRISS and 0.6--3.5 μ\mum with NIRSpec during transits of TRAPPIST-1b, f, and g. We discover Pα\alpha and Brβ\beta line emission and characterize flare continuum at wavelengths from 1--3.5 μ\mum for the first time. Observed lines include Hα\alpha, Pα\alpha-Pϵ\epsilon, Brβ\beta, He I λ\lambda0.7062μ\mum, two Ca II infrared triplet (IRT) lines, and the He I IRT. We observe a reversed Paschen decrement from Pα\alpha-Pγ\gamma alongside changes in the light curve shapes of these lines. The continuum of all four flares is well-described by blackbody emission with an effective temperature below 5300 K, lower than temperatures typically observed at optical wavelengths. The 0.6--1 μ\mum spectra were convolved with the TESS response, enabling us to measure the flare rate of TRAPPIST-1 in the TESS bandpass. We find flares of 1030^{30} erg large enough to impact transit spectra occur at a rate of 3.6+2.11.3\substack{+2.1 \\ -1.3} flare d1^{-1}, \sim10×\times higher than previous predictions from K2. We measure the amount of flare contamination at 2 μ\mum for the TRAPPIST-1b and f transits to be 500±\pm450 and 2100±\pm400 ppm, respectively. We find up to 80% of flare contamination can be removed, with mitigation most effective from 1.0--2.4 μ\mum. These results suggest transits affected by flares may still be useful for atmospheric characterization efforts.Comment: 29 pages, 17 figures, 3 tables, accepted to The Astrophysical Journa

    Determinants of Non-Vaccination against Pandemic 2009 H1N1 Influenza in Pregnant Women: A Prospective Cohort Study

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    International audienceBACKGROUND: In October 2009, the French government organized a national-wide, free of charge vaccination campaign against pandemic H1N1 influenza virus, especially targeting pregnant women, a high risk group for severe illness. The study objective was to evaluate pandemic flu vaccine uptake and factors associated with non-vaccination in a population of pregnant women. METHODOLOGY/PRINCIPAL FINDINGS: In a prospective cohort conducted in 3 maternity hospitals in Paris, 882 pregnant women were randomly included between October 12, 2009 and February 3, 2010, with the aim to study characteristics of pandemic influenza during pregnancy. At inclusion, socio-demographic, medical, obstetrical factors and those associated with a higher risk of flu exposition and disease-spreading were systematically collected. Pandemic flu vaccine uptake was checked until delivery. 555 (62.9%) women did not get vaccinated. Determinants associated with non-vaccination in a multivariate logistic regression were: geographic origin (Sub-Saharan African origin, adjusted Odd Ratio aOR = 5.4[2.3-12.7], North African origin, aOR = 2.5[1.3-4.7] and Asian origin, aOR = 2.1[1.7-2.6] compared to French and European origin) and socio-professional categories (farmers, craftsmen and tradesmen, aOR = 2.3[2.0-2.6], intermediate professionals, aOR = 1.3[1.0-1.6], employees and manual workers, aOR = 2.5[1.4-4.4] compared to managers and intellectual professionals). The probability of not receiving pandemic flu vaccine was lower among women vaccinated against seasonal flu in the previous 5 years (aOR = 0.6[0.4-0.8]) and among those who stopped smoking before or early during pregnancy (aOR = 0.6[0.4-0.8]). Number of children less than 18 years old living at home, work in contact with children or in healthcare area, or professional contact with the public, were not associated with a higher vaccine uptake. CONCLUSIONS/SIGNIFICANCE: In this cohort of pregnant women, vaccine coverage against pandemic 2009 A/H1N1 flu was low, particularly in immigrant women and those having a low socio-economic status. To improve its effectiveness, future vaccination campaign for pregnant women should be more specifically tailored for these populations

    How Do Aspirations Matter?

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    This paper explores the complex roles of aspirations in relation to human development, drawing upon the capability approach. The paper examines the notion of feasibility of aspirations and the impact feasibility judgements have on aspiration formation and aspiration realisation, in terms of both capabilities and functionings. In particular this paper extends existing theory by building on Hart’s (2004, 2012) dynamic multi-dimensional model of aspiration and Hart’s (2012) aspiration set. The theorization builds on empirical work, undertaken in the UK, seeking to understand pupil’s aspirations on leaving school and college at age 17-19 as well as reviewing wider empirical and theoretical literature in this field. The discussion contributes to capability theory by extending understanding regarding first, the way that aspirations are connected to capabilities and functionings, secondly, the processes by which aspirations are converted into capabilities and thirdly, how certain capabilities become functionings. The paper reflects on the criteria that inform choices about the cultivation and selection of different aspirations on individual and collective bases. )n concluding the paper the question of ‘how do aspirations matter?’ is addressed. Ultimately an argument is made for the need to ‘reclaim’ a rich multi-dimensional concept of aspiration in order to pursue human development and flourishing for all
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