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Glutamic endopeptidases (Glu), belonging to the class of serine proteases, are a subfamily of chymotrypsin‐like proteolytic enzymes, which are regarded as important virulence factors in bacteria. However, the roles of glutamic endopeptidases of Nocardia seriolae in pathogenic process still remain uncertain. Here, a glutamic endopeptidase homolog from N. seriolae (GluNS) was cloned and its function was elucidated. GluNS encoded a 414‐aa protein which shared 93% identity to N. concava. In the phylogenetic tree, the glutamic endopeptidases of genus Nocardia clustered together firstly and then clustered with Streptomyces species. Moreover, GluNS was identified to be a secreted protein of N. seriolae and localized in the mitochondria of FHM cells. The transient overexpression of GluNS significantly induced increase in caspase‐3 activity and decrease in ΔΨm values in FHM cells. The number of apoptotic bodies was remarkably higher than that in control group. Taken together, GluNS overexpression induced apoptotic characteristics in FHM cells. This study provided new insights into the function of glutamic endopeptidase from N. seriolae. [ABSTRACT FROM AUTHOR]

Fish nocardiosis is a chronic systemic granulomatous disease, and Nocardia seriolae is the main pathogen. The pathogenesis and virulence factors of N. seriolae are not fully understood. Secreted superoxide dismutase (SOD) may be a virulence factor found by a comparative bioinformatics analysis of the whole genome sequence of N. seriolae and the virulence factor database (VFDB). In order to determine the subcellular localization and study the preliminary function of SOD from N. seriolae (NsSOD), gene cloning, secreted protein identification, subcellular localization in fish cells, and apoptosis detection of NsSOD were carried out in this study. Subcellular localization research revealed that NsSOD‐GFP fusion proteins were evenly distributed in the cytoplasm. Furthermore, apoptotic bodies were observed in the transfected FHM cells by the overexpression of protein NsSOD. Then, assays of mitochondrial membrane potential (ΔΨm) value, caspase‐3 activity and apoptosis‐related genes (Bax, Bid, Bad and Bcl‐2) mRNA expression were conducted. The results showed that ΔΨm was decreased, and caspase‐3 was significantly activated. The mRNA expression of the Bad gene showed significant up‐regulated expression at 24 h.p.t., while Bid and Bax genes showed significant up‐regulated expression at 72 and 96 h.p.t. and anti‐apoptotic gene (Bcl‐2) was down‐regulated in NsSOD overexpressed cells. Taken together, the results indicated that the protein NsSOD might be involved in apoptosis regulation. This study may lay the foundations for further studies on the function of NsSOD and promote the understanding of the virulence factors and the pathogenic mechanisms of N. seriolae. [ABSTRACT FROM AUTHOR]

Nocardia seriolae is the main pathogen responsible for fish nocardiosis. A mitochondrial‐targeting secretory protein (MTSP) 3141 with an N‐terminal transit peptide (TP) from N. seriolae was predicted by bioinformatic analysis based on the genomic sequence of the N. seriolae strain ZJ0503. However, the function of the MTSP3141 and its homologs remains totally unknown. In this study, mass spectrometry analysis of the extracellular products from N. seriolae proved that MTSP3141 was a secretory protein, subcellular localization research showed the MTSP3141‐GFP fusion protein co‐localized with mitochondria in fathead minnow (FHM) cells, the TP played an important role in mitochondria targeting, and only the TP located at N‐terminus but not C‐terminus can lead to mitochondria directing. Moreover, quantitative assays of mitochondrial membrane potential (ΔΨm) value, caspase‐3 activity and apoptosis‐related gene (Bcl‐2, Bax, Bad, Bid and p53) mRNA expression suggested that cell apoptosis was induced in FHM cells by the overexpression of both MTSP3141 and MTSP3141ΔTP (with the N‐terminal TP deleted) proteins. Taken together, the results of this study indicated that the MTSP3141 of N. seriolae was a secretory protein, might target mitochondria, induce apoptosis in host cells and function as a virulence factor. [ABSTRACT FROM AUTHOR]

Nocardia seriolae, a facultative intracellular bacterium, is the main pathogen of fish nocardiosis. Bioinformatic analysis showed that the histone‐like DNA‐binding protein (HLP) gene of N. seriolae (nshlp) encoded a secreted protein and might target the mitochondria in the host cell. To further study the preliminary function of HLP in N. seriolae (NsHLP), the gene cloning, extracellular products identification, subcellular localization, overexpression and apoptosis detection assay were carried out in this study. Mass spectrometry analysis of the extracellular products from N. seriolae showed that NsHLP was a secreted protein. Subcellular localization of HLP‐GFP fusion proteins mainly assembled in the nucleus, which indicated that the NsHLP was co‐located with the nucleus rather than mitochondria in fathead minnow (FHM) cells. Notably, the expression of NsHLP had changed the distribution of mitochondria into lumps in the FHM cell. In addition, apoptotic features were found in the transfected FHM cells by overexpression of NsHLP. Quantitative assays of mitochondrial membrane potential value, caspase‐3 activity and pro‐apoptotic genes mRNA (Bad, Bid and Bax) expression level demonstrated that the cell apoptosis was induced in the transfected FHM cells. All the results presented in this study provided insight on the function of NsHLP, which suggested that it may participate in the cell apoptosis regulation and play an important role in the pathogenesis of N. seriolae. [ABSTRACT FROM AUTHOR]

Abstract: Highly uniform SrF2 and SrF2:Ln3+ (Ln=Er, Nd, Yb, Eu, Tb) hierarchical microspheres assembled by 2D nanoplates have been successfully synthesized by a facile and friendly hydrothermal route. X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and photoluminescence (PL) spectra were used to characterize the samples. The experimental results indicate that reaction time and chelating reagent play a key role in forming the hierarchical microspheres. The formation mechanism was proposed based on the evolution of this morphology as a function of hydrothermal time. The near-infrared luminescence of lanthanide ions (Er, Nd, and Yb) doped SrF2 microspheres were discussed in detail. In addition, the as-obtained SrF2:Eu3+ sample exhibits orange-red emission centered at 590nm under excitation at 393nm, while the SrF2:Tb3+ exhibits a strong green emission at 540nm. The as-synthesized SrF2:Ln3+ luminescent microspheres might find some potential applications in areas of photoluminescence, telecommunication and laser emission. [Copyright &y& Elsevier]

Abstract: Dumbbell-like microstructure of Ln-doped BaWO4 (Ln=Nd, Er, Yb) has been successfully synthesized via a very simple precipitation technique at room temperature without any templates or catalyst. The synthesized products were systematically studied by X-ray powder diffraction (XRD), field-emission scanning electron microscopy (FESEM), and transmission electron microscopy (TEM). Such a simple one-pot solution-based process may be extended to fabricate complex hierarchical micro- and nanostructures of other functional materials. Additionally, the near-infrared luminescence of Ln-doped BaWO4 (Ln=Nd, Er, Yb) dumbbells was discussed in detail. [Copyright &y& Elsevier]

Abstract: Uniform single-crystalline CoS2 nano-octahedrons have been prepared in high yield by a simple hydrothermal process. The octahedral structures exhibit a high geometric symmetry with smooth surfaces and the mean edge length is ~120nm. X-ray diffraction, scanning electron microscopy, transmission electron microscopy were used to characterize the samples. Contrast experiments indicate that the capping agent poly(vinyl pyrrolidone) (PVP) and the complexing agent sodium citrate play important roles for the formation of octahedral CoS2 nanostructures. A possible formation mechanism was proposed based on the evolution of this morphology as a function of hydrothermal time. Additionally, the magnetic properties of the CoS2 nano-octahedrons were discussed in detail. [Copyright &y& Elsevier]

Abstract: Uniform Cu3(OH)2V2O7·2H2O microspheres assembled by nanorods have been fabricated through a simple hydrothermal method for the first time employing copper hydroxide carbonate (Cu2(OH)2CO3) as copper source without the assistance of any template or surfactant. The formation mechanism was proposed based on the evolution of this morphology as a function of hydrothermal time. The Electrochemical measurements revealed that the Cu3(OH)2V2O7·2H2O microspheres displayed a high discharge capacity, which indicates that the Cu3(OH)2V2O7·2H2O microspheres are promising cathode candidates for primary lithium batteries used in long term implantable cardioverter defibrillators (ICD). [Copyright &y& Elsevier]

The preparation of exquisite hierarchical worm-like Co(1-x)S (x = 0.75) microtubes by a one-pot complex-surfactant-assisted hydrothermal method is successfully achieved for the first time. The hierarchical structures of the microtube wall are assembled from numerous interleaving hexagonal nanoplates. X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, transmission electron microscopy, and high-resolution transmission electron microscopy were used to characterize the samples. The experimental results indicate that the "soft template" surfactant cetyltrimethylammonium bromide and the chelating ethylenediamine both play important roles for the formation of hierarchical Co(1-x)S microtubes. A possible formation mechanism for the growth processes is proposed. Additionally, the electrochemical and magnetic properties of Co(1-x)S microtubes were systematically studied.