Neutrophil extracellular traps in bacterial infections and evasion strategies

Neutrophils are innate immune cells that have a vital role in host defense systems. Neutrophil extracellular traps (NETs) are one of neutrophils’ defense mechanisms against pathogens. NETs comprise an ejected lattice of chromatin associated with histones, granular proteins, and cytosolic proteins. They are thought to be an efficient strategy to capture and/or kill bacteria and received intensive research interest in the recent years. However, soon after NETs were identified, it was observed that certain bacteria were able to evade NET entrapment through many different mechanisms. Here, we outline the recent progress of NETs in bacterial infections and the strategies employed by bacteria to evade or withstand NETs. Identifying the molecules and mechanisms that modulate NET release will improve our understanding of the functions of NETs in infections and provide new avenues for the prevention and treatment of bacterial diseases

Finishing the euchromatic sequence of the human genome

The sequence of the human genome encodes the genetic instructions for human physiology, as well as rich information about human evolution. In 2001, the International Human Genome Sequencing Consortium reported a draft sequence of the euchromatic portion of the human genome. Since then, the international collaboration has worked to convert this draft into a genome sequence with high accuracy and nearly complete coverage. Here, we report the result of this finishing process. The current genome sequence (Build 35) contains 2.85 billion nucleotides interrupted by only 341 gaps. It covers ∼99% of the euchromatic genome and is accurate to an error rate of ∼1 event per 100,000 bases. Many of the remaining euchromatic gaps are associated with segmental duplications and will require focused work with new methods. The near-complete sequence, the first for a vertebrate, greatly improves the precision of biological analyses of the human genome including studies of gene number, birth and death. Notably, the human enome seems to encode only 20,000-25,000 protein-coding genes. The genome sequence reported here should serve as a firm foundation for biomedical research in the decades ahead

Promising SiC support for Pd catalyst in selective hydrogenation of acetylene to ethylene

In this study, SiC supported Pd nanoparticles were found to be an efficient catalyst in acetylene selective hydrogenation reaction. The ethylene selectivity can be about 20% higher than that on Pd/TiO2 catalyst at the same acetylene conversion at 90%. Moreover, Pd/SiC catalyst showed a stable catalytic life at 65 degrees C with 80% ethylene selectivity. With the detailed characterization using temperature-programmed reduction (H-2-TPR), powder X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), N-2 adsorption/desorption analysis, CO-chemisorption and thermo-gravimetric analysis (TGA), it was found that SiC owns a lower surface area (22.9 m(2)/g) and a broad distribution of meso-/macro-porosity (from 5 to 65 nm), which enhanced the mass transfer during the chemical process at high reaction rate and decreased the residence time of ethylene on catalyst surface. Importantly, SiC support has the high thermal conductivity, which favored the rapid temperature homogenization through the catalyst bed and inhabited the over-hydrogenation of acetylene. The surface electronic density of Pd on Pd/SiC catalyst was higher than that on Pd/TiO2, which could promote desorption of ethylene from surface of the catalyst. TGA results confirmed a much less coke deposition on Pd/SiC catalyst. (C) 2018 Elsevier B.V. All rights reserved

Genome-Wide Analysis of Mycoplasma dispar Provides Insights into Putative Virulence Factors and Phylogenetic Relationships

Mycoplasma dispar is an important pathogen involved in bovine respiratory disease, which causes huge economic losses worldwide. Our knowledge regarding the genomics, pathogenic mechanisms, and genetics of M. dispar is rather limited. In this study, the complete genome of M. dispar GS01 strain was sequenced using PacBio SMRT technology and first genome-wide analyzed. M. dispar GS01 has a single circular chromosome of 1,065,810 bp encoding 825 predicted proteins. Twenty-three potential virulence genes and two pathogenicity islands were identified in M. dispar. This pathogen was cytopathogenic, could form prolific biofilms, and could produce a large amount of H2O2. Methylation analysis revealed adenine and cytosine methylation across the genome and 13 distinct nucleotide motifs. Comparative analysis showed a high collinearity relationship between M. dispar GS01 and type strain ATCC 27140. Phylogenetic analysis demonstrated that M. dispar is genetically close to M. flocculare and M. hyopneumoniae. The data presented in this study will aid further study on the pathogenic mechanisms and evolution of M. dispar

Genome-Wide Analysis of Mycoplasma bovirhinis GS01 Reveals Potential Virulence Factors and Phylogenetic Relationships

Mycoplasma bovirhinis is a significant etiology in bovine pneumonia and mastitis, but our knowledge about the genetic and pathogenic mechanisms of M. bovirhinis is very limited. In this study, we sequenced the complete genome of M. bovirhinis strain GS01 isolated from the nasal swab of pneumonic calves in Gansu, China, and we found that its genome forms a 847,985 bp single circular chromosome with a GC content of 27.57% and with 707 protein-coding genes. The putative virulence determinants of M. bovirhinis were then analyzed. Results showed that three genomic islands and 16 putative virulence genes, including one adhesion gene enolase, seven surface lipoproteins, proteins involved in glycerol metabolism, and cation transporters, might be potential virulence factors. Glycerol and pyruvate metabolic pathways were defective. Comparative analysis revealed remarkable genome variations between GS01 and a recently reported HAZ141_2 strain, and extremely low homology with others mycoplasma species. Phylogenetic analysis demonstrated that M. bovirhinis was most genetically close to M. canis, distant from other bovine Mycoplasma species. Genomic dissection may provide useful information on the pathogenic mechanisms and genetics of M. bovirhinis

Impacts of SiC Carrier and Nickel Precursor of NiLa/support Catalysts for CO2 Selective Hydrogenation to Synthetic Natural Gas (SNG)

The porous silicon carbide (b-SiC) carrier supported nickellanthanum based catalysts (NiLa/SiC) were synthesized via incipient-wetness impregnation by using two types of nickel salts as the precursor, for the selective hydrogenation of carbon dioxide (CO2 + 4H(2)-> CH4 + 2H(2)O). The alumina supported catalysts were also prepared and tested for comparison. The samples were characterized using TEM, TPR, XRD, SEM, TG-DTG techniques. Compared to the Al2O3 supported catalysts, the SiC supported catalysts were more resistant to sintering and carbon deposition due to the high thermal conductivity of SiC support. The relative weak metal-support interaction on Ni nanoparticles supported on SiC carrier resulted in the easy reduction of active species during the activation process. Meanwhile, the performances of the catalysts prepared from nickel acetate were better than those of using nickel nitrate, while enhanced nickel dispersion and better reducibility of the catalyst from nickel acetate werr evidenced by TEM, TPR and XRD results. Catalytic performances exhibited that Ni-Ac-La/SiC catalyst possessed the higher activity with 89.4% conversion of CO2 and almost 100% selectivity to methane with slight deactivation after 3000 min test under reaction conditions

A facile approach for the preparation of biomorphic CuO-ZrO2 catalyst for catalytic combustion of methane

A series of novel biomorphic CuO-ZrO catalysts were prepared using a cotton bio-template and compared with conventional CuO-ZrO catalysts. The physical and chemical properties of the as-obtained catalysts were characterized by techniques including X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), H -temperature programmed reduction (H -TPR), and O -temperature programmed desorption (O -TPD). The catalytic combustion of methane was chosen as the probe reaction. The results suggested that the bio-template method prepared porous biomorphic CuO-ZrO catalysts consist of hollow microtubes. Comparing with conventional CuO-ZrO catalysts, biomorphic CuO-ZrO catalysts displayed better reducibility and oxygen mobility, stronger metal-oxides synergistic effect, appropriate particle size distribution, and lower activation energy. The crystalline state of zirconia transformed from a single crystallite phase of t-ZrO into a complex of m-ZrO and t-ZrO after introducing the bio-template. With proper CuO content (20 mol%), the biomorphic CuO-ZrO catalyst displayed preponderant properties. The compensation of surface lattice oxygen from bulk lattice oxygen was more available at high reaction temperatures