Toll-like receptor 3 in Epstein-Barr virus-associated nasopharyngeal carcinomas: consistent expression and cytotoxic effects of its synthetic ligand poly(A:U) combined to a Smac-mimetic.

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Increase of the peroxidase activity of cytochrome c-550 by the interaction with detergents

The effect was studied of detergents on the peroxidase activity of the heme-containing electron-transport protein, cytochrome c-550 from Paracoccus versutus (cytc550). Cytc550 does not interact with non-ionic or zwitterionic detergents, but its peroxidase activity is significantly enhanced in the presence of both anionic and cationic detergents. The increase in peroxidase activity is caused by (partial) unfolding of cytc550, resulting in weakening of the bond between the axial methionine ligand and the heme-iron. With sodium dodecyl sulfate (SDS) and dodecyltrimethylammonium bromide (DTAB), the activity increases roughly 10- and 100-fold, respectively. The detergent concentration required to enhance the peroxidase activity of cytc550 consistently coincides with the critical micellisation concentration (CMC). When cytc550 carries substantial opposite charge to that of the detergent headgroup, the protein-detergent complex is formed at lower detergent concentration than the critical micellisation concentration, i.e. at acid pH for anionic detergent and at alkaline pH for cationic detergent. It is concluded that in the presence of ionic detergents, cytc550 can acquire considerable peroxidase activity. This may be exploited by applying cytc550 as an oxidative catalyst in detergent-rich environments, where regular peroxidases rapidly lose their catalytic potential. (C) 2003 Elsevier B.V. All rights reserved.Macromolecular Biochemistr

A Guide to Noxious Plants as an Educational Resource of Veterinary Medicine Students

The School of Veterinary UNRN is located in the town of Choele Choel (39° 17\u27S, 65° 39\u27W), in Northern Patagonia, Argentina. The climate is semi-arid with a historical average annual continental rainfall of 303 mm, with marked daily and seasonal temperature ranges. However, the type of vegetation that can be found in the area ranges fromxerophytic shrubs to hydrophytic vegetation because the arid plateau is crossed by the broad valley of Río Negro. Due to the topographic distribution of agricultural and livestock farms, the toxic plants for livestock may be found in the irrigated valleys or arid shrubby camps

Exosomes released by EBV-infected nasopharyngeal carcinoma cells convey the viral Latent Membrane Protein 1 and the immunomodulatory protein galectin 9

BACKGROUND: Nasopharyngeal carcinomas (NPC) are consistently associated with the Epstein-Barr virus (EBV). Their malignant epithelial cells contain the viral genome and express several antigenic viral proteins. However, the mechanisms of immune escape in NPCs are still poorly understood. EBV-transformed B-cells have been reported to release exosomes carrying the EBV-encoded latent membrane protein 1 (LMP1) which has T-cell inhibitory activity. Although this report suggested that NPC cells could also produce exosomes carrying immunosuppressive proteins, this hypothesis has remained so far untested. METHODS: Malignant epithelial cells derived from NPC xenografts – LMP1-positive (C15) or negative (C17) – were used to prepare conditioned culture medium. Various microparticles and vesicles released in the culture medium were collected and fractionated by differential centrifugation. Exosomes collected in the last centrifugation step were further purified by immunomagnetic capture on beads carrying antibody directed to HLA class II molecules. Purified exosomes were visualized by electron microscopy and analysed by western blotting. The T-cell inhibitory activities of recombinant LMP1 and galectin 9 were assessed on peripheral blood mononuclear cells activated by CD3/CD28 cross-linking. RESULTS: HLA-class II-positive exosomes purified from C15 and C17 cell supernatants were containing either LMP1 and galectin 9 (C15) or galectin 9 only (C17). Recombinant LMP1 induced a strong inhibition of T-cell proliferation (IC50 = 0.17 nM). In contrast recombinant galectin 9 had a weaker inhibitory effect (IC50 = 46 nM) with no synergy with LMP1. CONCLUSION: This study provides the proof of concept that NPC cells can release HLA class-II positive exosomes containing galectin 9 and/or LMP1. It confirms that the LMP1 molecule has intrinsic T-cell inhibitory activity. These findings will encourage investigations of tumor exosomes in the blood of NPC patients and assessment of their effects on various types of target cells

Data filtering in the readout of the CMS Electromagnetic Calorimeter

For an efficient data taking, the Electromagnetic Calorimeter (ECAL) data of the CMS experiment must be limited to 10\% of the full event size (1MB). Other requirements limit the average data size to 2kB per data acquisition link. These conditions imply a reduction factor of close to twenty on the data collected. The data filtering in the readout of the ECAL detector is discussed. Test beam data are used to study the digital filtering applied in the readout channels and a full detector simulation allows to estimate the energy thresholds to achieve the desired data suppression factor