225 research outputs found
Classical Solutions of Path-dependent PDEs and Functional Forward-Backward Stochastic Systems
In this paper we study the relationship between functional forward-backward
stochastic systems and path-dependent PDEs. In the framework of functional
It\^o calculus, we introduce a path-dependent PDE and prove that its solution
is uniquely determined by a functional forward-backward stochastic system.Comment: arXiv admin note: text overlap with arXiv:1108.431
Solutions for Functional Fully Coupled Forward-Backward Stochastic Differential Equations
In this paper, we study a functional fully coupled forward-backward
stochastic differential equations (FBSDEs). Under a new type of integral
Lipschitz and monotonicity conditions, the existence and uniqueness of
solutions for functional fully coupled FBSDEs is proved. We also investigate
the relationship between the solution of functional fully coupled FBSDE and the
classical solution of the path-dependent partial differential equation (P-PDE).
When the solution of the P-PDE has some smooth and regular properties, we solve
the related functional fully coupled FBSDE and prove the P-PDE has a unique
solution
Non-Markovian Fully Coupled Forward-Backward Stochastic Systems and Classical Solutions of Path-dependent PDEs
This paper explores the relationship between non-Markovian fully coupled
forward-backward stochastic systems and path-dependent PDEs. The definition of
classical solution for the path-dependent PDE is given within the framework of
functional It\^{o} calculus. Under mild hypotheses, we prove that the
forward-backward stochastic system provides the unique classical solution to
the path-dependent PDE.Comment: arXiv admin note: text overlap with arXiv:1108.431
The Site Specific Demethylation in the 5β²-Regulatory Area of NMDA Receptor 2B Subunit Gene Associated with CIE-Induced Up-Regulation of Transcription
The NMDA receptor represents a particularly important site of ethanol action in the CNS. We recently reported that NMDA receptor 2B (NR2B) gene expression was persistently up-regulated following chronic intermittent ethanol (CIE) treatment. Increasing evidence that epigenetic mechanisms are involved in dynamic and long-lasting regulation of gene expression in multiple neuroadaptive processes prompted us to investigate the role of DNA methylation in mediating CIE-induced up-regulation of NR2B gene transcription. To dissect the changes of DNA methylation in the NR2B gene, we have screened a large number of CpG sites within its 5β²-regulatory area following CIE treatment. DNA methylation assays were performed to determine the direct impact of DNA methylation on the interaction between DNA and transcription factor and promoter activity. of methylated DNA decreased transcription factor binding activity and promoter activity. An additional ChIP assay indicated that the CIE-induced DNA demethylation is accompanied by increased occupation by transcription factors.These results suggest an important role of DNA demethylation in mediating CIE-induced NR2B gene up-regulation, thus implicating a novel molecular site of alcohol action
Novel plasmid-mediated colistin resistance gene mcr-3 in Escherichia coli
The mobile colistin resistance gene mcr-1 has attracted global attention,
as it heralds the breach of polymyxins, one of the last-resort antibiotics for
the treatment of severe clinical infections caused by multidrug-resistant Gramnegative
bacteria. To date, six slightly different variants of mcr-1, and a second
mobile colistin resistance gene, mcr-2, have been reported or annotated in the
GenBank database. Here, we characterized a third mobile colistin resistance gene,
mcr-3. The gene coexisted with 18 additional resistance determinants in the 261-kb
IncHI2-type plasmid pWJ1 from porcine Escherichia coli. mcr-3 showed 45.0% and
47.0% nucleotide sequence identity to mcr-1 and mcr-2, respectively, while the deduced
amino acid sequence of MCR-3 showed 99.8 to 100% and 75.6 to 94.8% identity
to phosphoethanolamine transferases found in other Enterobacteriaceae species
and in 10 Aeromonas species, respectively. pWJ1 was mobilized to an E. coli recipient
by conjugation and contained a plasmid backbone similar to those of other mcr-
1-carrying plasmids, such as pHNSHP45-2 from the original mcr-1-harboring E. coli
strain. Moreover, a truncated transposon element, TnAs2, which was characterized
only in Aeromonas salmonicida, was located upstream of mcr-3 in pWJ1. This
ΞTnAs2-mcr-3 element was also identified in a shotgun genome sequence of a porcine
E. coli isolate from Malaysia, a human Klebsiella pneumoniae isolate from Thailand,
and a human Salmonella enterica serovar Typhimurium isolate from the United
States. These results suggest the likelihood of a wide dissemination of the novel mobile
colistin resistance gene mcr-3 among Enterobacteriaceae and aeromonads; the
latter may act as a potential reservoir for mcr-3.
IMPORTANCE The emergence of the plasmid-mediated colistin resistance gene mcr-1
has attracted substantial attention worldwide. Here, we examined a colistin-resistant
Escherichia coli isolate that was negative for both mcr-1 and mcr-2 and discovered a
novel mobile colistin resistance gene, mcr-3. The amino acid sequence of MCR-3
aligned closely with phosphoethanolamine transferases from Enterobacteriaceae and
Aeromonas species originating from both clinical infections and environmental samples
collected in 12 countries on four continents. Due to the ubiquitous profile of
aeromonads in the environment and the potential transfer of mcr-3 between Enterobacteriaceae
and Aeromonas species, the wide spread of mcr-3 may be largely underestimated.
As colistin has been and still is widely used in veterinary medicine and
used at increasing frequencies in human medicine, the continuous monitoring of
mobile colistin resistance determinants in colistin-resistant Gram-negative bacteria is
imperative for understanding and tackling the dissemination of mcr genes in both
the agricultural and health care sectors
Presence of VIM-positive pseudomonas species in chickens and their surrounding environment
Metallo-Ξ²-lactamase gene blaVIM was identified on the chromosome of four Pseudomonas sp. isolates from a chicken farm, including one Pseudomonas aeruginosa isolate from a swallow (Yanornis martini), one Pseudomonas putida isolate from a fly, and two P. putida isolates from chickens. The four isolates shared two variants of blaVIM-carrying genomic contexts that resemble the corresponding regions of clinical metallo-Ξ²-lactamase-producing Pseudomonas spp. Our study suggests that the surveillance of carbapenemase-producing bacteria in livestock and their surrounding environment is urgently needed
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