With the aim of gathering temporal trends on bacterial epidemiology and resistance from multiple laboratories in China, the CHINET surveillance system was organized in 2005. Antimicrobial ...susceptibility testing was carried out according to a unified protocol using the Kirby-Bauer method or automated systems. Results were analyzed according to Clinical and Laboratory Standards Institute (CLSI) 2014 definitions. Between 2005 and 2014, the number of bacterial isolates ranged between 22 774 and 84 572 annually. Rates of extended-spectrum β-lactamase production among Escherichia coli isolates were stable, between 51.7 and 55.8%. Resistance of E. coli and Klebsiella pneumoniae to amikacin, ciprofloxacin, piperacillin/tazobactam and cefoperazone/sulbactam decreased with time. Carbapenem resistance among K. pneumoniae isolates increased from 2.4 to 13.4%. Resistance of Pseudomonas aeruginosa strains against all of antimicrobial agents tested including imipenem and meropenem decreased with time. On the contrary, resistance of Acinetobacter baumannii strains to carbapenems increased from 31 to 66.7%. A marked decrease of methicillin resistance from 69% in 2005 to 44.6% in 2014 was observed for Staphylococcus aureus. Carbapenem resistance rates in K. pneumoniae and A. baumannii in China are high. Our results indicate the importance of bacterial surveillance studies.
In Alzheimer's disease (AD), neurodegenerative signals such as amyloid-beta (Aβ) and the precursors of neurotrophins, outbalance neurotrophic signals, causing synaptic dysfunction and ...neurodegeneration. The neurotrophin receptor p75 (p75NTR) is a receptor of Aβ and mediates Aβ-induced neurodegenerative signals. The shedding of its ectodomain from the cell surface is physiologically regulated; however, the function of the diffusible p75NTR ectodomain (p75ECD) after shedding remains largely not known. Here, we show that p75ECD levels in cerebrospinal fluid and in the brains of Alzheimer's patients and amyloid-beta precursor protein (APP)/PS1 transgenic mice were significantly reduced, due to inhibition of the sheddase-tumor necrosis factor-alpha-converting enzyme by Aβ. Restoration of p75ECD to the normal level by brain delivery of the gene encoding human p75ECD before or after Aβ deposition in the brain of APP/PS1 mice reversed the behavioral deficits and AD-type pathologies, such as Aβ deposit, apoptotic events, neuroinflammation, Tau phosphorylation and loss of dendritic spine, neuronal structures and synaptic proteins. Furthermore, p75ECD can also reduce amyloidogenesis by suppressing β-secretase expression and activities. Our data demonstrate that p75ECD is a physiologically neuroprotective molecule against Aβ toxicity and would be a novel therapeutic target and biomarker for AD.
Summary
Erdheim–Chester disease (ECD), a type of systemic non‐Langerhans cell histiocytosis, is uncommon and characterized by the accumulation of CD68+CD1a− foamy histiocytes. It is extremely rare in ...children. The skin lesions of paediatric ECD have not been systemically described before. We report a case of ECD in a 3·5‐year‐old Chinese boy. The patient presented with generalized skin and bone involvement of 3 years’ duration. Marked generalized annular maculopapular lesions with central atrophy were seen. These differed from previously reported adult xanthoma‐like papules or periorbital xanthelasma‐like lesions. Computed tomography revealed diffuse pulmonary fibrosis and generalized skeletal involvement, including osteolysis and osteosclerosis. The presence of CD68+CD1a− histiocytes allowed the diagnosis of ECD. According to our review of the literature, this is the paediatric case of ECD with the youngest age of onset. The generalized skin involvement made our case unique in comparison with those previously reported.
What's already known about this topic?
Erdheim–Chester disease (ECD) is extremely rare in children, and skin lesions have not been described systemically before.
What does this study add?
The patient presented with generalized annular maculopapular lesions with central atrophy, which differed from previously reported xanthoma‐like papules or periorbital xanthelasma‐like lesions.
Computed tomography and the presence of CD68+CD1a− histiocytes allowed the diagnosis of ECD to be made.
The case described here has the youngest age of onset reported, and the generalized skin involvement makes it unique in comparison with previous reports.
Linked Comment: Chasset and Haroche. Br J Dermatol 2018; 178:31–32.
Abstract
As a novel X-ray focusing technology, lobster-eye micropore optics (MPO) feature both a wide observing field of view and true imaging capability, promising sky monitoring with significantly ...improved sensitivity and spatial resolution in soft X-rays. Since first proposed by Angel, the optics have been extensively studied, developed and trialed over the past decades. In this Letter, we report on the first-light results from a flight experiment of the Lobster Eye Imager for Astronomy, a pathfinder of the wide-field X-ray telescope of the Einstein Probe mission. The piggyback imager, launched in 2022 July, has a mostly unvignetted field of view of 18.°6 × 18.°6. Its spatial resolution is in the range of 4′–7′ in FWHM and the focal spot effective area is 2–3 cm
2
, both showing only mild fluctuations across the field of view. We present images of the Galactic center region, Sco X-1, and the diffuse Cygnus Loop nebular taken in snapshot observations over 0.5–4 keV. These are truly wide-field X-ray images of celestial bodies observed, for the first time, by a focusing imaging telescope. Initial analyses of the in-flight data show excellent agreement between the observed images and the on-ground calibration and simulations. The instrument and its characterization are briefly described, as well as the flight experiment. The results provide a solid basis for the development of the present and proposed wide-field X-ray missions using lobster-eye MPO.
Industrial polyploid yeast strains harbor numerous beneficial traits but suffer from a lack of available auxotrophic markers for genetic manipulation. Here we demonstrated a quick and efficient ...strategy to generate auxotrophic markers in industrial polyploid yeast strains with the RNA-guided Cas9 nuclease. We successfully constructed a quadruple auxotrophic mutant of a popular industrial polyploid yeast strain, Saccharomyces cerevisiae ATCC 4124, with ura3, trp1, leu2, and his3 auxotrophies through RNA-guided Cas9 nuclease. Even though multiple alleles of auxotrophic marker genes had to be disrupted simultaneously, we observed knockouts in up to 60% of the positive colonies after targeted gene disruption. In addition, growth-based spotting assays and fermentation experiments showed that the auxotrophic mutants inherited the beneficial traits of the parental strain, such as tolerance of major fermentation inhibitors and high temperature. Moreover, the auxotrophic mutants could be transformed with plasmids containing selection marker genes. These results indicate that precise gene disruptions based on the RNA-guided Cas9 nuclease now enable metabolic engineering of polyploid S. cerevisiae strains that have been widely used in the wine, beer, and fermentation industries.
Nowadays, it is still questionable whether denatured collagen (DCol) can replace the native collagen (Col) as a bioactive protein in cartilage engineering. We sought to study the advantages of Col ...with a triple-helical structure in the collagen-based composite materials for cartilage engineering.
We presented new three-dimensional (3D) Col and DCol scaffolds with shape memory properties. The effects of Col and DCol scaffolds on rabbit chondrocytes' proliferation, adhesion, differentiation and interaction with matrix were investigated. Tissue compatibility was performed in a subcutaneous Sprague Dawley (SD) rat model. The repair ability of different scaffolds with chondrocytes for full-thickness articular cartilage defects in knee joints of New Zealand white rabbits were investigated.
The results indicated that the Col scaffolds (with concentration 1.6wt% and 0.8wt%, respectively) promoted the proliferation, adhesion and redifferentiation of chondrocytes, as well as chondrocyte–matrix interaction, to a greater degree than the DCol scaffolds. In the animal experiment, the Col scaffolds filled in the defect hole significantly maintained chondrocytes function, promoted cartilage and subchondral bone regeneration, compared with the DCol scaffolds, and the scaffolds loaded with chondrocytes were better than the cell-free scaffolds, especially in the case of the Col scaffolds (1.6 wt%).
Taken together, these insights suggest that the better proliferation, adhesion and redifferentiation of chondrocytes in Col scaffolds with the triple-helical structure may contribute to the greater cartilage repair ability. Col scaffolds may be more appropriate for repairing cartilage defects than DCol scaffolds, and DCol cannot as an alternative when using collagen-based materials for cartilage engineering applications.
The use of plant biomass for biofuel production will require efficient utilization of the sugars in lignocellulose, primarily glucose and xylose. However, strains of Saccharomyces cerevisiae ...presently used in bioethanol production ferment glucose but not xylose. Yeasts engineered to ferment xylose do so slowly, and cannot utilize xylose until glucose is completely consumed. To overcome these bottlenecks, we engineered yeasts to coferment mixtures of xylose and cellobiose. In these yeast strains, hydrolysis of cellobiose takes place inside yeast cells through the action of an intracellular β-glucosidase following import by a high-affinity cellodextrin transporter. Intracellular hydrolysis of cellobiose minimizes glucose repression of xylose fermentation allowing coconsumption of cellobiose and xylose. The resulting yeast strains, cofermented cellobiose and xylose simultaneously and exhibited improved ethanol yield when compared to fermentation with either cellobiose or xylose as sole carbon sources. We also observed improved yields and productivities from cofermentation experiments performed with simulated cellulosic hydrolyzates, suggesting this is a promising cofermentation strategy for cellulosic biofuel production. The successful integration of cellobiose and xylose fermentation pathways in yeast is a critical step towards enabling economic biofuel production.
Background: Alkaline serine proteases from six prevalent airborne Penicillium and Aspergillus species have been identified as a group of major allergens (group 13). After entering human airways, the ...allergens are in initial contacts with respiratory epithelial cells. The purpose of this study is to investigate interactions between the Pen ch 13 allergen from P. chrysogenum and human lung epithelial cells.
Methods: A549 cells, 16HBE14o‐ cells and primary cultures of human bronchial epithelial cells (HBEpC) were exposed to purified Pen ch 13 and mediators released into culture supernatants were assayed with enzyme‐linked immunosorbent assay (ELISA) kits. Cleavage of occludin in 16HBE14o‐ cells was analysed by immunofluorescent staining of whole cells and immunoblot analysis of whole cell extracts. Fragments generated by incubating Pen ch 13 and a synthetic peptide carrying the occludin sequence were analysed by mass spectrometry.
Results: Pen ch 13 induced productions of prostaglandin‐E2 (PGE2), interleukin (IL)‐8 and transforming growth factor (TGF)‐β1 by A549 cells, 16HBE14o‐ cells and primary cultures of HBEpC. The protease activity of Pen ch 13 is needed for the induction of PGE2, IL‐8, TGF‐β1 and cyclo‐oxygenase (COX)‐2 expression. A tight junction protein occludin of 16HBE14o‐ cells can be cleaved by Pen ch 13 at Gln202 and Gln211 which are within the second extracellular domain of the protein.
Conclusion: Pen ch 13 may contribute to asthma by damaging the barrier formed by the airway epithelium and stimulating the release of mediators that orchestrate local immune responses and inflammatory process from HBEpC.
Isomerases perform biotransformations without cofactors but often cause an undesirable mixture of substrate and product due to unfavorable thermodynamic equilibria. We demonstrate the feasibility of ...using an engineered yeast strain harboring oxidoreductase reactions to overcome the thermodynamic limit of an isomerization reaction. Specifically, a yeast strain capable of consuming lactose intracellularly is engineered to produce tagatose from lactose through three layers of manipulations. First, GAL1 coding for galactose kinase is deleted to eliminate galactose utilization. Second, heterologous xylose reductase (XR) and galactitol dehydrogenase (GDH) are introduced into the ∆gal1 strain. Third, the expression levels of XR and GDH are adjusted to maximize tagatose production. The resulting engineered yeast produces 37.69 g/L of tagatose from lactose with a tagatose and galactose ratio of 9:1 in the reaction broth. These results suggest that in vivo oxidoreaductase reactions can be employed to replace isomerases in vitro for biotransformation.
PDF
