84 research outputs found

    Ultrasound-mediated Gene Transfer to Enhance Bioremediation of Contaminated Water

    Get PDF
    A novel technique for in situ bioremediation is vital to enable the world to meet the need to treat contaminated land; ultrasound gene transfer has that potential. Ultrasound gene transfer has been shown to be a non-invasive, low impact and practical for engineering method of to delivering plasmid DNA and macro-molecules into bacteria. For the first time delivery of a salicylate hydroxylase gene into P. putida UWC1 has been demonstrated, enabling the complete degradation of the salicylate contaminant, which the wild type was unable to degrade, has been demonstrated. Furthermore not only DNA but also macro-molecules (e.g. fluorescent tagged large dextran molecules, up to 2,000,000 MW) have been delivered into P. putida UWC1 using UGT. This can potentially enable delivery of bioparts and nanomaterials for synthetic biology to targeted locations in an organism. To achieve this,: a novel variable frequency ultrasonic generator has been developed to deliver focussed ultrasound through the sonotrode directly into an aqueous bacterial sample. This sonotrode was designed to operate at the optimum frequency for UGT of 27.5 kHz determined using the preliminary apparatus and has enabled the application of UGT to > ~50 ml samples, demonstrating scalability to industrial application (i.e. using an array of sonotrodes to treat litres of environmental sample for re-introduction). The optimum frequency enables a satisfactory rate of transfer (10-7 efficiency) whilst minimising cell lysis (<90% cell survival) making it ideal for environmental application as it will minimise unnecessary disruption to the ecosystem. The mechanism behind UGT has been determined as transfer peaks at the resonant frequencies where cavitation microbubbles are produced. It is the collapse of these microbubbles that generates microjets of extremely high pressure that affect the cell walls of the bacteria enabling uptake of the DNA or macro-molecules. Thus it is shown that the emerging technology of ultrasound gene transfer can deliver novel genes directly into bacteria with minimal preparation and minimal impact to the cells

    SDSS-IV MaNGA: drivers of stellar metallicity in nearby galaxies

    Get PDF
    The distribution of stellar metallicities within and across galaxies is an excellent relic of the chemical evolution across cosmic time. We present a detailed analysis of spatially resolved stellar populations based on >2.6 million spatial bins from 7439 nearby galaxies in the Sloan Digital Sky Survey-IV (SDSS-IV) Mapping Nearby Galaxies at APO (MaNGA) survey. To account for accurate inclination corrections, we derive an equation for morphology-dependent determination of galaxy inclinations. Our study goes beyond the well-known global mass-metallicity relation and radial metallicity gradients by providing a statistically sound exploration of local relations between stellar metallicity [Z/H], stellar surface mass density Σ∗, and galactocentric distance in the global mass-morphology plane. We find a significant resolved mass density-metallicity relation Σ ZR for galaxies of all types and masses above 109.8 M⊙. Different radial distances make an important contribution to the spread of the relation. Particularly, in low- and intermediate-mass galaxies, we find that at fixed Σ∗ metallicity increases with radius independently of morphology. For high masses, this radial dependence is only observed in high Σ∗ regions of spiral galaxies. This result calls for a driver of metallicity, in addition to Σ∗ that promotes chemical enrichment in the outer parts of galaxies more strongly than in the inner parts. We discuss gas accretion, outflows, recycling, and radial migration as possible scenarios.The Science and Technology Facilities Council is acknowledged for support through the Consolidated Grant Cosmology and Astrophysics at Portsmouth, ST/S000550/1. JL is supported by the National Science Foundation under Grant No. 2009993. JKB-B acknowledges support from the grant IA-100420 (DGAPA-PAPIIT, UNAM), and funding from the CONACYT grants CF 19-39578, CB-285080, and FC-2016-01-1916

    State Control and the Effects of Foreign Relations on Bilateral Trade

    Get PDF
    Do states use trade to reward and punish partners? WTO rules and the pressures of globalization restrict states’ capacity to manipulate trade policies, but we argue that governments can link political goals with economic outcomes using less direct avenues of influence over firm behavior. Where governments intervene in markets, politicization of trade is likely to occur. In this paper, we examine one important form of government control: state ownership of firms. Taking China and India as examples, we use bilateral trade data by firm ownership type, as well as measures of bilateral political relations based on diplomatic events and UN voting to estimate the effect of political relations on import and export flows. Our results support the hypothesis that imports controlled by state-owned enterprises (SOEs) exhibit stronger responsiveness to political relations than imports controlled by private enterprises. A more nuanced picture emerges for exports; while India’s exports through SOEs are more responsive to political tensions than its flows through private entities, the opposite is true for China. This research holds broader implications for how we should think about the relationship between political and economic relations going forward, especially as a number of countries with partially state-controlled economies gain strength in the global economy

    Testing the sensitivity of Tract-Based Spatial Statistics to simulated treatment effects in preterm neonates

    Get PDF
    Early neuroimaging may provide a surrogate marker for brain development and outcome after preterm birth. Tract-Based Spatial Statistics (TBSS) is an advanced Diffusion Tensor Image (DTI) analysis technique that is sensitive to the effects of prematurity and may provide a quantitative marker for neuroprotection following perinatal brain injury or preterm birth. Here, we test the sensitivity of TBSS to detect diffuse microstructural differences in the developing white matter of preterm infants at term-equivalent age by modelling a 'treatment' effect as a global increase in fractional anisotropy (FA). As proof of concept we compare these simulations to a real effect of increasing age at scan. 3-Tesla, 15-direction diffusion tensor imaging (DTI) was acquired from 90 preterm infants at term-equivalent age. Datasets were randomly assigned to 'treated' or 'untreated' groups of increasing size and voxel-wise increases in FA were used to simulate global treatment effects of increasing magnitude in all 'treated' maps. 'Treated' and 'untreated' FA maps were compared using TBSS. Predictions from simulated data were then compared to exemplar TBSS group comparisons based on increasing postmenstrual age at scan. TBSS proved sensitive to global differences in FA within a clinically relevant range, even in relatively small group sizes, and simulated data were shown to predict well a true biological effect of increasing age on white matter development. These data confirm that TBSS is a sensitive tool for detecting global group-wise differences in FA in this population

    Convergent evolution of chicken Z and human X chromosomes by expansion and gene acquisition

    Get PDF
    In birds, as in mammals, one pair of chromosomes differs between the sexes. In birds, males are ZZ and females ZW. In mammals, males are XY and females XX. Like the mammalian XY pair, the avian ZW pair is believed to have evolved from autosomes, with most change occurring in the chromosomes found in only one sex—the W and Y chromosomes1, 2, 3, 4, 5. By contrast, the sex chromosomes found in both sexes—the Z and X chromosomes—are assumed to have diverged little from their autosomal progenitors2. Here we report findings that challenge this assumption for both the chicken Z chromosome and the human X chromosome. The chicken Z chromosome, which we sequenced essentially to completion, is less gene-dense than chicken autosomes but contains a massive tandem array containing hundreds of duplicated genes expressed in testes. A comprehensive comparison of the chicken Z chromosome with the finished sequence of the human X chromosome demonstrates that each evolved independently from different portions of the ancestral genome. Despite this independence, the chicken Z and human X chromosomes share features that distinguish them from autosomes: the acquisition and amplification of testis-expressed genes, and a low gene density resulting from an expansion of intergenic regions. These features were not present on the autosomes from which the Z and X chromosomes originated but were instead acquired during the evolution of Z and X as sex chromosomes. We conclude that the avian Z and mammalian X chromosomes followed convergent evolutionary trajectories, despite their evolving with opposite (female versus male) systems of heterogamety. More broadly, in birds and mammals, sex chromosome evolution involved not only gene loss in sex-specific chromosomes, but also marked expansion and gene acquisition in sex chromosomes common to males and females.National Science Foundation (U.S.)Howard Hughes Medical Institut

    Avian W and mammalian Y chromosomes convergently retained dosage-sensitive regulators

    Get PDF
    After birds diverged from mammals, different ancestral autosomes evolved into sex chromosomes in each lineage. In birds, females are ZW and males are ZZ, but in mammals females are XX and males are XY. We sequenced the chicken W chromosome, compared its gene content with our reconstruction of the ancestral autosomes, and followed the evolutionary trajectory of ancestral W-linked genes across birds. Avian W chromosomes evolved in parallel with mammalian Y chromosomes, preserving ancestral genes through selection to maintain the dosage of broadly expressed regulators of key cellular processes. We propose that, like the human Y chromosome, the chicken W chromosome is essential for embryonic viability of the heterogametic sex. Unlike other sequenced sex chromosomes, the chicken W chromosome did not acquire and amplify genes specifically expressed in reproductive tissues. We speculate that the pressures that drive the acquisition of reproduction-related genes on sex chromosomes may be specific to the male germ line

    Para-infectious brain injury in COVID-19 persists at follow-up despite attenuated cytokine and autoantibody responses

    Get PDF
    To understand neurological complications of COVID-19 better both acutely and for recovery, we measured markers of brain injury, inflammatory mediators, and autoantibodies in 203 hospitalised participants; 111 with acute sera (1–11 days post-admission) and 92 convalescent sera (56 with COVID-19-associated neurological diagnoses). Here we show that compared to 60 uninfected controls, tTau, GFAP, NfL, and UCH-L1 are increased with COVID-19 infection at acute timepoints and NfL and GFAP are significantly higher in participants with neurological complications. Inflammatory mediators (IL-6, IL-12p40, HGF, M-CSF, CCL2, and IL-1RA) are associated with both altered consciousness and markers of brain injury. Autoantibodies are more common in COVID-19 than controls and some (including against MYL7, UCH-L1, and GRIN3B) are more frequent with altered consciousness. Additionally, convalescent participants with neurological complications show elevated GFAP and NfL, unrelated to attenuated systemic inflammatory mediators and to autoantibody responses. Overall, neurological complications of COVID-19 are associated with evidence of neuroglial injury in both acute and late disease and these correlate with dysregulated innate and adaptive immune responses acutely
    corecore