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A few members of the bacterial genus Thermus have been shown to be incomplete denitrifiers, terminating with nitrite (NO2−) or nitrous oxide (N2O). However, the denitrification abilities of the genus as a whole remain poorly characterized. Here, we describe diverse denitrification phenotypes and genotypes of a collection of 24 strains representing ten species, all isolated from a variety of geothermal systems in China. Confirmed terminal products of nitrate reduction were nitrite or N2O, while nitric oxide (NO) was inferred as the terminal product in some strains. Most strains produced N2O; complete denitrification was not observed. Denitrification phenotypes were largely consistent with the presence of denitrification genes, and strains of the same species often had the same denitrification phenotypes and largely syntenous denitrification gene clusters. Genes for nirS and nirK coexisted in three Thermus brockianus and three Thermus oshimai genomes, which is a unique hallmark of some denitrifying Thermus strains and may be ecologically important. These results show that incomplete denitrification phenotypes are prominent, but variable, within and between Thermus species. The incomplete denitrification phenotypes described here suggest Thermus species may play important roles in consortial denitrification in high-temperature terrestrial biotopes where sufficient supply of oxidized inorganic nitrogen exists. [ABSTRACT FROM AUTHOR]

Although transition metal sulfides have presented prospect in electrochemical sensing, their electrocatalytic performance still cannot meet the demands for practical applications due to the difficulties in mass transport and electron transfer. In this work, double-shelled CuS nanocages (2-CuS NCs) were prepared for enzyme-free ascorbic (AA) sensor through a Cu2O- templated method. The unique double-shelled hollow structure displayed large specific surface areas, ordered diffusion channels, increased volume occupying rate, and accelerated electron transfer rate, resulting in enhanced electrochemical dynamic. As a sensing electrode for AA, 2-CuS NCs modified glassy carbon electrode (2-CuS NCs/GCE) exhibited eminent electrocatalytic activity in terms of satisfying sensitivity (523.7 μA mM−1 cm−2), short response time (0.31 s), and low limit of detection (LOD, 0.15 μM). 2-CuS NCs look promising for analytical sensing of AA in electrochemical sensors thanks to its prominent electrocatalytic kinetics issued from double-shelled hollow porous structure. [ABSTRACT FROM AUTHOR]

Porcine epidemic diarrhea virus (PEDV) has caused devastating impact on pig-rearing industry in China and current vaccine is not effective against the circulating PEDV variants. In the present study, the full-length genome sequence from a PEDV isolate (CH/HNQX-3/14) was determined. The complete genome sequence analysis showed that the CH/HNQX-3/14 possessed unique deletion regions in the S and ORF3 genes. It was identified as a recombinant strain using phylogenetic analysis and recombination detection program. Further analyses of the full-length sequence suggest that CH/HNQX-3/14 is a natural recombinant between the attenuated vaccine strains (CV777 and DR13) and circulating wild-type strain (CH/ZMDZY/11). The recombination occurred not only in structural protein-coding region (S1 and N genes) but also in non-structural protein-coding region (replicases 1a and ORF3 genes). These results provided new evidence that PEDV strains circulating in China underwent recombination between vaccine and field strains, suggesting that recombination contributes to the genetic diversity of PEDV. Our findings provide valuable information on PEDV evolution and underscore the need for ongoing surveillance of this economically important swine disease. [ABSTRACT FROM AUTHOR]

Since 2010, porcine epidemic diarrhea has re-emerged with devastating impact on the swine-raising industry in central China. To investigate the epidemic characteristics of PEDV, the complete ORF3 genes of 14 PEDV field strains from central China during 2012 to 2013 were cloned, sequenced and compared with reference strains. Phylogenetic analysis based on the complete ORF3 gene showed that the PEDVs in central China and the reference strains could be divided into three groups: G1, G2, and G3. The 14 PEDV isolates were classified as G1 and showed a close relationship to some Chinese strains isolated previously in central China and differed genetically from recent isolates from southern China, Korean strains (SM98 and DB1865, 2012), the Chinese LZC strain (2007), and the vaccine strain (CV777) being used in China. Our findings suggested that the PEDVs circulating between 2012 and 2013 in central China might have evolved from earlier strains in the local region. To determine the reason for recent vaccination failures, we also studied variations in antigenicity of field strains by analyzing the three neutralizing epitope regions in the S gene. The results showed that the neutralizing epitopes at aa 245-252 were highly conserved, but most of the amino acid changes occurred in the epitope regions aa 7-146 and 271-278. We speculate that the amino acid mutations in the neutralizing epitope regions may be associated with changes in the antigenicity of PEDV and consequently result in vaccination failure. Together, these findings may be useful for understanding the epidemiology of PEDV and may be relevant for designing of new and more efficacious vaccines. [ABSTRACT FROM AUTHOR]

An extracellular xylanase from halophilic Streptomonospora sp. YIM 90494 was purified to homogeneity from a fermentation broth by ammonium sulphate precipitation, gel filtration chromatography and ion exchange chromatography. The purified xylanase appeared as a single protein band on SDS-PAGE with a molecular mass of approximately 50 kDa. The xylanase had maximum activity at pH 7.5 and 55 °C. The enzyme was stable over a broad pH range (pH 4.0-10.0) and showed good thermal stability when being incubated at 60 °C for 2 h. Kinetic experiments indicated that the enzyme had K and V values of 19.24 mg/mL and 6.1 μmol/min/mg, respectively, using birch wood xylan as substrate. The inhibitory effects of various metal ions and chemical agents on the xylanase activity were investigated. It is greatly interesting to note that Ag ion and SDS, which strongly inhibited most xylanases reported previously increases the xylanase activity in this study. These characteristics suggest that the enzyme with new properties has considerable potential in industrial applications. [ABSTRACT FROM AUTHOR]

As typical electrode materials for supercapacitors, low specific capacitance and insufficient cycling stability of transition metal oxides (TMOs) are still the problems that need to be solved. Design of core-shell structure is considered as an effective method for preparation of high-performance electrode materials. In this work, NiO flakes@CoMoO4 nanosheets/Ni foam (NiO flakes@CoMoO4 NSs/NF) core-shell architecture was constructed by a two-step hydrothermal method. Interestingly, the CoMoO4 NSs are vertically grown on the surface of NiO flakes, forming a two-dimensional (2D) branched core-shell structure. The porous core-shell architecture has relatively high surface area, effective ions channels, and abundant redox sites, resulting in excellent electrochemical performance. As a positive electrode for supercapacitors, NiO flakes@CoMoO4 NSs/NF core-shell architecture exhibits excellent capacitive performance in terms of high specific capacitance (1097 F/g at 1 A/g) and outstanding cycling stability (97.5% after 2000 circles). The assembled asymmetric supercapacitor (ASC) of NiO flakes@CoMoO4 NSs/NF//active carbon (AC)/NF possesses a maximum energy density of 25.8 Wh/kg at power density of 894.7 W/kg. The results demonstrate that NiO flakes@CoMoO4 NSs/NF electrode displays potential applications in supercapacitors and the design of 2D branched core-shell architecture paves an ideal way to obtain high-performance TMOs electrodes. [ABSTRACT FROM AUTHOR]