51 research outputs found
VirBR, a transcription regulator, promotes IncX3 plasmid transmission, and persistence of bla NDM-5 in zoonotic bacteria
IncX3 plasmids carrying the New Delhi metallo-β-lactamase-encoding gene, blaNDM-5, are rapidly spreading globally in both humans and animals. Given that carbapenems are listed on the WHO AWaRe watch group and are prohibited for use in animals, the drivers for the successful dissemination of Carbapenem-Resistant Enterobacterales (CRE) carrying blaNDM-5-IncX3 plasmids still remain unknown. We observe that E. coli carrying blaNDM-5-IncX3 can persist in chicken intestines either under the administration of amoxicillin, one of the largest veterinary β-lactams used in livestock, or without any antibiotic pressure. We therefore characterise the blaNDM-5-IncX3 plasmid and identify a transcription regulator, VirBR, that binds to the promoter of the regulator gene actX enhancing the transcription of Type IV secretion systems (T4SS); thereby, promoting conjugation of IncX3 plasmids, increasing pili adhesion capacity and enhancing the colonisation of blaNDM-5-IncX3 transconjugants in animal digestive tracts. Our mechanistic and in-vivo studies identify VirBR as a major factor in the successful spread of blaNDM-5-IncX3 across one-health AMR sectors. Furthermore, VirBR enhances the plasmid conjugation and T4SS expression by the presence of copper and zinc ions, thereby having profound ramifications on the use of universal animal feeds
Brain Injury Accelerates the Onset of a Reversible Age-Related Microglial Phenotype Associated With Inflammatory Neurodegeneration
Lipofuscin is an autofluorescent (AF) pigment formed by lipids and misfolded proteins, which accumulates in postmitotic cells with advanced age. Here, we immunophenotyped microglia in the brain of old C57BL/6 mice (\u3e18 months old) and demonstrate that in comparison to young mice, one-third of old microglia are AF, characterized by profound changes in lipid and iron content, phagocytic activity, and oxidative stress. Pharmacological depletion of microglia in old mice eliminated the AF microglia following repopulation and reversed microglial dysfunction. Age-related neurological deficits and neurodegeneration after traumatic brain injury (TBI) were attenuated in old mice lacking AF microglia. Furthermore, increased phagocytic activity, lysosomal burden, and lipid accumulation in microglia persisted for up to 1 year after TBI, were modified b
Insight-HXMT observations of Swift J0243.6+6124 during its 2017-2018 outburst
The recently discovered neutron star transient Swift J0243.6+6124 has been
monitored by {\it the Hard X-ray Modulation Telescope} ({\it Insight-\rm HXMT).
Based on the obtained data, we investigate the broadband spectrum of the source
throughout the outburst. We estimate the broadband flux of the source and
search for possible cyclotron line in the broadband spectrum. No evidence of
line-like features is, however, found up to . In the absence of
any cyclotron line in its energy spectrum, we estimate the magnetic field of
the source based on the observed spin evolution of the neutron star by applying
two accretion torque models. In both cases, we get consistent results with
, and peak luminosity of which makes the source the first Galactic ultraluminous
X-ray source hosting a neutron star.Comment: publishe
Overview to the Hard X-ray Modulation Telescope (Insight-HXMT) Satellite
As China's first X-ray astronomical satellite, the Hard X-ray Modulation
Telescope (HXMT), which was dubbed as Insight-HXMT after the launch on June 15,
2017, is a wide-band (1-250 keV) slat-collimator-based X-ray astronomy
satellite with the capability of all-sky monitoring in 0.2-3 MeV. It was
designed to perform pointing, scanning and gamma-ray burst (GRB) observations
and, based on the Direct Demodulation Method (DDM), the image of the scanned
sky region can be reconstructed. Here we give an overview of the mission and
its progresses, including payload, core sciences, ground calibration/facility,
ground segment, data archive, software, in-orbit performance, calibration,
background model, observations and some preliminary results.Comment: 29 pages, 40 figures, 6 tables, to appear in Sci. China-Phys. Mech.
Astron. arXiv admin note: text overlap with arXiv:1910.0443
A Signed Subgraph Encoding Approach via Linear Optimization for Link Sign Prediction
In this paper, we consider the problem of inferring the sign of a link based
on limited sign data in signed networks. Regarding this link sign prediction
problem, SDGNN (Signed Directed Graph Neural Networks) provides the best
prediction performance currently to the best of our knowledge. In this paper,
we propose a different link sign prediction architecture call SELO (Subgraph
Encoding via Linear Optimization), which obtains overall leading prediction
performances compared the state-of-the-art algorithm SDGNN. The proposed model
utilizes a subgraph encoding approach to learn edge embeddings for signed
directed networks. In particular, a signed subgraph encoding approach is
introduced to embed each subgraph into a likelihood matrix instead of the
adjacency matrix through a linear optimization method. Comprehensive
experiments are conducted on six real-world signed networks with AUC, F1,
micro-F1, and Macro-F1 as the evaluation metrics. The experiment results show
that the proposed SELO model outperforms existing baseline feature-based
methods and embedding-based methods on all the six real-world networks and in
all the four evaluation metrics
An analysis of fixation probability of a mutant on a class of weighted networks under neutral selection
Recently, evolutionary dynamics on structured population has attracted an increasing attention in various fields. This paper aims at investigating the fixation probability of a mutant under random drift on a class of weighted networks. In particular, we have attained the analytical solutions of fixation probability of mutants on the weighted networks with three different updating rules, including link dynamics, Moran process, and voter model. It should be especially pointed out that the above analytical solutions can be used to further understand and control the evolution processes. Numerical simulations are also given to validate the above analytical solutions. © 2011 IEEE
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