1.Orientation-Selective Alignments of Hydroxyapatite Nanoblocks through Epitaxial Attachment in a and c Directions.
Nakamura K1, Nakagawa Y1, Kageyama H1, Oaki Y1, Imai H1. Langmuir. 2016 Apr 14. [Epub ahead of print]
Nanometric rods of hydroxyapatite (HA) were aligned in selective crystallographic directions by the alternation of adsorbing molecules. The side and end faces of HA nanorods elongated in the c direction were covered with oleic acid (OA) and tetraoctylammonium (TOA) ions, respectively. Alignment in the c direction of the OA-modified nanorods was produced through epitaxial attachment of the bare end faces in toluene because the side faces were hydrophobized with the negatively charged modifier. Another alignment-in the a direction of the TOA-modified HA nanorods-was obtained through the epitaxial attachment of the bare side faces in ethanol due to stabilization of the end faces with the positively charged modifier. Controlled alignments of the nanorods in the a and c directions were achieved through oriented attachment with the selective coverage of the c and a faces with the specific modifiers.
2.Perfluoroalkylated substances effects in Xenopus laevis A6 kidney epithelial cells determined by ATR-FTIR spectroscopy and chemometric analysis.
Gorrochategui E, Lacorte S, Tauler R, Martin FL. Chem Res Toxicol. 2016 Apr 14. [Epub ahead of print]
The effects of four perfluoroalkylated substances (PFASs), namely, perfluorobutanesulfonate (PFBS), perfluorooctanoic acid (PFOA), perfluorooctanesulfonate (PFOS) and perfluorononanoic acid (PFNA) were assessed in Xenopus laevis A6 kidney epithelial cells by attenuated total reflection Fourier-transform infrared (ATR-FTIR) spectroscopy and chemometric analysis. Principal component analysis-linear discriminant analysis (PCA-LDA) was used to visualize wavenumber-related alterations and ANOVA-simultaneous component analysis (ASCA) allowed data processing considering the underlying experimental design. Both analyses evidenced a higher impact of low-dose PFAS-treatments (10-9 M) on A6 cells forming monolayers, while there was a larger influence of high-dose PFAS-treatments (10-5 M) on A6 cells differentiated into dome structures. The observed dose-response PFAS-induced effects were to some extent related to their cytotoxicity: the EC50-values of most influent PFAS-treatments increased (PFOS<PFNA<PFOA<<PFBS), higher-doses of these chemicals induced a larger impact.
3.Initiation of RNA Polymerization and Polymerase Encapsidation by a Small dsRNA Virus.
Collier AM1, Lyytinen OL2, Guo YR1, Toh Y1, Poranen MM2, Tao YJ1. PLoS Pathog. 2016 Apr 14;12(4):e1005523. doi: 10.1371/journal.ppat.1005523. eCollection 2016.
During the replication cycle of double-stranded (ds) RNA viruses, the viral RNA-dependent RNA polymerase (RdRP) replicates and transcribes the viral genome from within the viral capsid. How the RdRP molecules are packaged within the virion and how they function within the confines of an intact capsid are intriguing questions with answers that most likely vary across the different dsRNA virus families. In this study, we have determined a 2.4 Å resolution structure of an RdRP from the human picobirnavirus (hPBV). In addition to the conserved polymerase fold, the hPBV RdRP possesses a highly flexible 24 amino acid loop structure located near the C-terminus of the protein that is inserted into its active site. In vitro RNA polymerization assays and site-directed mutagenesis showed that: (1) the hPBV RdRP is fully active using both ssRNA and dsRNA templates; (2) the insertion loop likely functions as an assembly platform for the priming nucleotide to allow de novo initiation; (3) RNA transcription by the hPBV RdRP proceeds in a semi-conservative manner; and (4) the preference of virus-specific RNA during transcription is dictated by the lower melting temperature associated with the terminal sequences.
4.Neutrophil Isolation and Analysis to Determine their Role in Lymphoma Cell Sensitivity to Therapeutic Agents.
Hirz T1, Dumontet C2. J Vis Exp. 2016 Mar 25;(109). doi: 10.3791/53846.
Neutrophils are the most abundant (40% to 75%) type of white blood cells and among the first inflammatory cells to migrate towards the site of inflammation. They are key players in the innate immune system and play major roles in cancer biology. Neutrophils have been proposed as key mediators of malignant transformation, tumor progression, angiogenesis and in the modulation of the antitumor immunity; through their release of soluble factors or their interaction with tumor cells. To characterize the specific functions of neutrophils, a fast and reliable method is coveted for in vitro isolation of neutrophils from human blood. Here, a density gradient separation method is demonstrated to isolate neutrophils as well as mononuclear cells from the blood. The procedure consists of layering the density gradient solution such as Ficoll carefully above the diluted blood obtained from patients diagnosed with chronic lymphocytic leukemia (CLL), followed by centrifugation, isolation of mononuclear layer, separation of neutrophils from RBCsby dextran then lysis of residual erythrocytes.
