64 research outputs found
Assessing the bioconfinement potential of a Nicotiana hybrid platform for use in plant molecular farming applications
Background
The introduction of pharmaceutical traits in tobacco for commercial production could benefit from the utilization of a transgene bioconfinement system. It has been observed that interspecific F1Nicotiana hybrids (Nicotiana tabacum × Nicotiana glauca) are sterile and thus proposed that hybrids could be suitable bioconfined hosts for biomanufacturing. We genetically tagged hybrids with green fluorescent protein (GFP), which was used as a visual marker to enable gene flow tracking and quantification for field and greenhouse studies. GFP was used as a useful proxy for pharmaceutical transgenes. Results
Analysis of DNA content revealed significant genomic downsizing of the hybrid relative to that of N. tabacum. Hybrid pollen was capable of germination in vitro, albeit with a very low frequency and with significant differences between plants. In two field experiments, one each in Tennessee and Kentucky, we detected outcrossing at only one location (Tennessee) at 1.4%. Additionally, from 50 hybrid plants at each field site, formation of 84 and 16 seed was observed, respectively. Similar conclusions about hybrid fertility were drawn from greenhouse crosses. In terms of above-ground biomass, the hybrid yield was not significantly different than that of N. tabacum in the field. Conclusion
N. tabacum × N. glauca hybrids show potential to contribute to a bioconfinement- and biomanufacturing host system. Hybrids exhibit extremely low fertility with no difference of green biomass yields relative to N. tabacum. In addition, hybrids are morphologically distinguishable from tobacco allowing for identity preservation. This hybrid system for biomanufacturing would optimally be used where N. glauca is not present and in physical isolation of N. tabacum production to provide total bioconfinement
Protease-activated receptor 4 variant p.Tyr157Cys reduces platelet functional responses and alters receptor trafficking
OBJECTIVE—: Protease-activated receptor 4 (PAR4) is a key regulator of platelet reactivity and is encoded by F2RL3, which has abundant rare missense variants. We aimed to provide proof of principle that rare F2LR3 variants potentially affect on platelet reactivity and responsiveness to PAR1 antagonist drugs and to explore underlying molecular mechanisms. APPROACH AND RESULTS—: We identified 6 rare F2RL3 missense variants in 236 cardiac patients, of which the variant causing a tyrosine 157 to cysteine substitution (Y157C) was predicted computationally to affect most on PAR4 structure. Y157C platelets from 3 cases showed reduced responses to PAR4-activating peptide and to α-thrombin compared with controls, but no reduction in responses to PAR1-activating peptide. Pretreatment with the PAR1 antagonist vorapaxar caused lower residual α-thrombin responses in Y157C platelets than in controls, indicating greater platelet inhibition. HEK293 cells transfected with a PAR4 Y157C expression construct had reduced PAR4 functional responses, unchanged total PAR4 expression but reduced surface expression. PAR4 Y157C was partially retained in the endoplasmic reticulum and displayed an expression pattern consistent with defective N-glycosylation. Mutagenesis of Y322, which is the putative hydrogen bond partner of Y157, also reduced PAR4 surface expression in HEK293 cells. CONCLUSIONS—: Reduced PAR4 responses associated with Y157C result from aberrant anterograde surface receptor trafficking, in part, because of disrupted intramolecular hydrogen bonding. Characterization of PAR4 Y157C establishes that rare F2RL3 variants have the potential to markedly alter platelet PAR4 reactivity particularly after exposure to therapeutic PAR1 antagonists
An orange fluorescent protein tagging system for real-time pollen tracking
BACKGROUND: Monitoring gene flow could be important for future transgenic crops, such as those producing plant-made-pharmaceuticals (PMPs) in open field production. A Nicotiana hybrid (Nicotiana. tabacum x Nicotiana glauca) shows limited male fertility and could be used as a bioconfined PMP platform. Effective assessment of gene flow from these plants is augmented with methods that utilize fluorescent proteins for transgenic pollen identification.
RESULTS: We report the generation of a pollen tagging system utilizing an orange fluorescent protein to monitor pollen flow and as a visual assessment of transgene zygosity of the parent plant. This system was created to generate a tagged Nicotiana hybrid that could be used for the incidence of gene flow. Nicotiana tabacum \u27TN 90\u27 and Nicotiana glauca were successfully transformed via Agrobacterium tumefaciens to express the orange fluorescent protein gene, tdTomato-ER, in pollen and a green fluorescent protein gene, mgfp5-er, was expressed in vegetative structures of the plant. Hybrids were created that utilized the fluorescent proteins as a research tool for monitoring pollen movement and gene flow. Manual greenhouse crosses were used to assess hybrid sexual compatibility with N. tabacum, resulting in seed formation from hybrid pollination in 2% of crosses, which yielded non-viable seed. Pollen transfer to the hybrid formed seed in 19% of crosses and 10 out of 12 viable progeny showed GFP expression.
CONCLUSION: The orange fluorescent protein is visible when expressed in the pollen of N. glauca, N. tabacum, and the Nicotiana hybrid, although hybrid pollen did not appear as bright as the parent lines. The hybrid plants, which show limited ability to outcross, could provide bioconfinement with the benefit of detectable pollen using this system. Fluorescent protein-tagging could be a valuable tool for breeding and in vivo ecological monitoring
Parsec-scale radio structures in the nuclei of four Seyfert galaxies
We present 18-cm radio maps of four Seyfert nuclei, Mrk 1, Mrk 3, Mrk 231 and
Mrk 463E, made with the European VLBI Network (EVN). Linear radio structures
are present in three out of four sources on scales of ~100 pc to ~1 kpc, and
the 20-mas beam of the EVN enables us to resolve details within the radio
structures on scales of <10 pc. Mrk 3 was also imaged using MERLIN and the data
combined with the EVN data to improve the sensitivity to extended emission. We
find an unresolved flat-spectrum core in Mrk 3, which we identify with the
hidden Seyfert 1 nucleus in this object, and we also see marked differences
between the two highly-collimated radio jets emanating from the core. The
western jet terminates in a bright hotspot and resembles an FRII radio
structure, whilst the eastern jet has more in common with an FRI source. In Mrk
463E, we use the radio and optical structure of the source to argue that the
true nucleus lies approximately 1 arcsec south of the position of the radio and
optical brightness peaks, which probably represent a hotspot at the working
surface of a radio jet. The EVN data also provide new evidence for a 100-pc
radio jet powering the radio source in the Type 1 nucleus of Mrk 231. However,
the Seyfert 2 galaxy Mrk 1 shows no evidence for radio jets down to the limits
of resolution (~10 pc). We discuss the range of radio source size and
morphology which can occur in the nuclei of Seyfert galaxies and the
implications for Seyfert unification schemes and for radio surveys of large
samples of objects.Comment: 23 pages, 7 postscript figures (supplied as separate files), uses AAS
aaspp4 LaTeX style file, to appear in the 10 June 1999 issue of The
Astrophysical Journa
Trends and Impacts of Real and Financial Globalization in the People's Republic of China and India since the 1980s
The dynamic process of integration of national economies has a long history, with two distinct waves: one, from the middle of the 19th century until its interruption with outbreak of the First World War in 1913 till the end of the Second World War in 1945. The second wave is ongoing dating from 1950. Two sub-processes of integration are usually distinguished. The first, called real integration related to flows of goods, services and factors across borders; the second called financial integration related to financial flows of claims on the nominal returns on financial assets. Financial integration has had a checkered history. Private financial flows, particularly debt flows, were evident in the first wave. During the second wave, debt flows, both intergovernmental and private banking lending were dominant during 1950–1980. Only after 1980, private non-debt flows particularly equity flows accelerated. This paper's primary focus is on the real and financial integration and their impact on trade, growth and poverty in the world's two dominant developing countries in emerging markets, namely the People's Republic of China (PRC) and India. The paper also discusses the reforms of institutional (domestic and multinational) foundations of real and financial integration, particularly the World Trade Organization, the World Bank, the International Monetary Fund, and the Group of 20. The impacts of the 2008–2009 financial crisis on the PRC and India are noted and the need for domestic financial sector reforms in both for them to cope with and respond to future financial crises is pointed out. Attention is drawn to the inadequacy of available analytical tools, in particular the absence of an appropriately integrated model of real and financial sectors to enable a meaningful assessment of the impact of financial shocks on the real sector
Multi-messenger observations of a binary neutron star merger
On 2017 August 17 a binary neutron star coalescence candidate (later designated GW170817) with merger time 12:41:04 UTC was observed through gravitational waves by the Advanced LIGO and Advanced Virgo detectors. The Fermi Gamma-ray Burst Monitor independently detected a gamma-ray burst (GRB 170817A) with a time delay of ~1.7 s with respect to the merger time. From the gravitational-wave signal, the source was initially localized to a sky region of 31 deg2 at a luminosity distance of 40+8-8 Mpc and with component masses consistent with neutron stars. The component masses were later measured to be in the range 0.86 to 2.26 Mo. An extensive observing campaign was launched across the electromagnetic spectrum leading to the discovery of a bright optical transient (SSS17a, now with the IAU identification of AT 2017gfo) in NGC 4993 (at ~40 Mpc) less than 11 hours after the merger by the One- Meter, Two Hemisphere (1M2H) team using the 1 m Swope Telescope. The optical transient was independently detected by multiple teams within an hour. Subsequent observations targeted the object and its environment. Early ultraviolet observations revealed a blue transient that faded within 48 hours. Optical and infrared observations showed a redward evolution over ~10 days. Following early non-detections, X-ray and radio emission were discovered at the transient’s position ~9 and ~16 days, respectively, after the merger. Both the X-ray and radio emission likely arise from a physical process that is distinct from the one that generates the UV/optical/near-infrared emission. No ultra-high-energy gamma-rays and no neutrino candidates consistent with the source were found in follow-up searches. These observations support the hypothesis that GW170817 was produced by the merger of two neutron stars in NGC4993 followed by a short gamma-ray burst (GRB 170817A) and a kilonova/macronova powered by the radioactive decay of r-process nuclei synthesized in the ejecta
A Model of an Optimum Currency Area
This paper develops a model of the circumstances under which it is beneficial to participate in a currency area. The proposed two-country monetary model of trade with nominal rigidities encompasses the real and monetary arguments suggested by the optimum currency area literature: correlation of real and monetary shocks, international factor mobility, fiscal adjustment, openness, difference in national inflationary biases, and transactions costs. The effect of openness on the net benefits is ambiguous, contrary to the usual argument that more open economies are better candidates for a currency area. Also, prospective member countries do not necessarily agree on whether a given currency union should be created
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