91 research outputs found
High Quality Long-Term CD4+ and CD8+ Effector Memory Populations Stimulated by DNA-LACK/MVA-LACK Regimen in Leishmania major BALB/c Model of Infection
Heterologous vaccination based on priming with a plasmid DNA vector and boosting with an attenuated vaccinia virus MVA recombinant, with both vectors expressing the Leishmania infantum LACK antigen (DNA-LACK and MVA-LACK), has shown efficacy conferring protection in murine and canine models against cutaneus and visceral leishmaniasis, but the immune parameters of protection remain ill defined. Here we performed by flow cytometry an in depth analysis of the T cell populations induced in BALB/c mice during the vaccination protocol DNA-LACK/MVA-LACK, as well as after challenge with L. major parasites. In the adaptive response, there is a polyfunctional CD4+ and CD8+ T cell activation against LACK antigen. At the memory phase the heterologous vaccination induces high quality LACK-specific long-term CD4+ and CD8+ effector memory cells. After parasite challenge, there is a moderate boosting of LACK-specific CD4+ and CD8+ T cells. Anti-vector responses were largely CD8+-mediated. The immune parameters induced against LACK and triggered by the combined vaccination DNA/MVA protocol, like polyfunctionality of CD4+ and CD8+ T cells with an effector phenotype, could be relevant in protection against leishmaniasis
The TianQin project: Current progress on science and technology
TianQin is a planned space-based gravitational wave (GW) observatory consisting of three Earth-orbiting satellites with an orbital radius of about 105km\u2060. The satellites will form an equilateral triangle constellation the plane of which is nearly perpendicular to the ecliptic plane. TianQin aims to detect GWs between 10 124Hz and 1Hz that can be generated by a wide variety of important astrophysical and cosmological sources, including the inspiral of Galactic ultra-compact binaries, the inspiral of stellar-mass black hole binaries, extreme mass ratio inspirals, the merger of massive black hole binaries, and possibly the energetic processes in the very early universe and exotic sources such as cosmic strings. In order to start science operations around 2035, a roadmap called the 0123 plan is being used to bring the key technologies of TianQin to maturity, supported by the construction of a series of research facilities on the ground. Two major projects of the 0123 plan are being carried out. In this process, the team has created a new-generation 17cm single-body hollow corner-cube retro-reflector which was launched with the QueQiao satellite on 21 May 2018; a new laser-ranging station equipped with a 1.2m telescope has been constructed and the station has successfully ranged to all five retro-reflectors on the Moon; and the TianQin-1 experimental satellite was launched on 20 December 2019\u2014the first-round result shows that the satellite has exceeded all of its mission requirements
Analyses of carnivore microsatellites and their intimate association with tRNA-derived SINEs
BACKGROUND: The popularity of microsatellites has greatly increased in the last decade on account of their many applications. However, little is currently understood about the factors that influence their genesis and distribution among and within species genomes. In this work, we analyzed carnivore microsatellite clones from GenBank to study their association with interspersed repeats and elucidate the role of the latter in microsatellite genesis and distribution. RESULTS: We constructed a comprehensive carnivore microsatellite database comprising 1236 clones from GenBank. Thirty-three species of 11 out of 12 carnivore families were represented, although two distantly related species, the domestic dog and cat, were clearly overrepresented. Of these clones, 330 contained tRNA(Lys)-derived SINEs and 357 contained other interspersed repeats. Our rough estimates of tRNA SINE copies per haploid genome were much higher than published ones. Our results also revealed a distinct juxtaposition of AG and A-rich repeats and tRNA(Lys)-derived SINEs suggesting their coevolution. Both microsatellites arose repeatedly in two regions of the insterspersed repeat. Moreover, microsatellites associated with tRNA(Lys)-derived SINEs showed the highest complexity and less potential instability. CONCLUSION: Our results suggest that tRNA(Lys)-derived SINEs are a significant source for microsatellite generation in carnivores, especially for AG and A-rich repeat motifs. These observations indicate two modes of microsatellite generation: the expansion and variation of pre-existing tandem repeats and the conversion of sequences with high cryptic simplicity into a repeat array; mechanisms which are not specific to tRNA(Lys)-derived SINEs. Microsatellite and interspersed repeat coevolution could also explain different distribution of repeat types among and within species genomes. Finally, due to their higher complexity and lower potential informative content of microsatellites associated with tRNA(Lys)-derived SINEs, we recommend avoiding their use as genetic markers
Managing Imbalanced Supply Chain Relationships for Sustainability: A Power Perspective
This study adopts a power perspective to investigate sustainable supply chain relationships and specifically uses resource dependence theory (RDT) to critically analyze buyerâsupplierâsupplier relationships. Empirical evidence is provided, extending the RDT model in this context. The concept of power relationships is explored through a qualitative study of a multinational company and agricultural growers in the UK food industry that work together to implement sustainable practices. We look at multiple triadic relationships involving a large buyer and its small suppliers to investigate how relative power affects the implementation of sustainable supply-management practices. The study highlights that power as dependence is relevant to understanding compliance in sustainable supply chains and to identifying appropriate relationship-management strategies to build more sustainable supply chains. We show the influences of power on how players manage their relationships and how it affects organizational responses to the implementation of sustainability initiatives. Power notably influences the sharing of sustainability-related risks and value between supply chain partners. From a managerial perspective, the study contributes to developing a better understanding of how power can become an effective way to achieve sustainability goals. This paper offers insights into the way in which a large organization works with small and medium size enterprises (SMEs) to implement sustainable practices and shows how power managementâthat is, the way in which power is usedâcan support or hinder effective cooperation around sustainability in the supply chain
High resolution lake sediment record reveals self-organized criticality in erosion processes regulated by internal feedbacks
Reconstruction of highâfrequency erosion variability beyond the instrumental record requires wellâdated, highâresolution proxies from sediment archives. We used computed tomography (CT) scans of finely laminated silt layers from a lakeâsediment record in southwest Oregon to quantify the magnitude of natural landscape erosion events over the last 2000âyears in order to compare with palaeorecords of climate, forest fire, and seismic triggers. Sedimentation rates were modeled from an ageâdepth relationship fit through five 14C dates and the 1964âAD 137Cs peak in which deposition time (yrâmmâ1) varied inversely with the proportion of silt sediment measured by the CT profile. This model resulted in pseudoâannual estimates of silt deposition for the last 2000âyears. Silt accumulation during the past 80âyears was strongly correlated with riverâdischarge at annual and decadal scales, revealing that erosion was highly responsive to precipitation during the logging era (1930âpresent). Before logging the frequencyâmagnitude relationship displayed a powerâlaw distribution that is characteristic of complex feedbacks and selfâregulating mechanisms. The 100âyear and 10âyear erosion magnitude estimated in a 99âyear moving window varied by 1.7 and 1.0 orders of magnitude, respectively. Decadal erosion magnitude was only moderately positively correlated with a summer temperature reconstruction over the period 900â1900âAD. Magnitude of the seven largest events was similar to the cumulative silt accumulation anomaly, suggesting these events âreturned the systemâ to the longâterm mean rate. Instead, the occurrence of most erosion events was related to fire (silt layers preceded by high charcoal concentration) and earthquakes (the seven thickest layers often match paleoâearthquake dates). Our data show how internal (i.e. sediment production) and external processes (natural fires or more stochastic events such as earthquakes) coâdetermine erosion regimes at millennial time scales, and the extent to which such processes can be offset by recent largeâscale deforestation by logging
A whole-genome shotgun approach for assembling and anchoring the hexaploid bread wheat genome
Citation: Chapman, J. A., Mascher, M., Buluç, A., Barry, K., Georganas, E., Session, A., . . . Rokhsar, D. S. (2015). A whole-genome shotgun approach for assembling and anchoring the hexaploid bread wheat genome. Genome Biology, 16(1). doi:10.1186/s13059-015-0582-8Polyploid species have long been thought to be recalcitrant to whole-genome assembly. By combining high-throughput sequencing, recent developments in parallel computing, and genetic mapping, we derive, de novo, a sequence assembly representing 9.1 Gbp of the highly repetitive 16 Gbp genome of hexaploid wheat, Triticum aestivum, and assign 7.1 Gb of this assembly to chromosomal locations. The genome representation and accuracy of our assembly is comparable or even exceeds that of a chromosome-by-chromosome shotgun assembly. Our assembly and mapping strategy uses only short read sequencing technology and is applicable to any species where it is possible to construct a mapping population. © 2015 Chapman et al. licensee BioMed Central.Additional Authors: Muehlbauer, G. J.;Stein, N.;Rokhsar, D. S
Minnestal \uf6ver professoren Fredrik Johan Wiik, hallet vid Finska vetenskapssocietetens ars- och h\uf6gtidsdag den 23 maj 1910,
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