Targeting ie-1 gene by RNAi induces baculoviral resistance in lepidopteran cell lines and in transgenic silkworms

RNA interference (RNAi)-mediated viral inhibition has been used in a few organisms for eliciting viral resistance. In the present study, we report the use of RNAi in preventing baculovirus infection in a lepidopteran. We targeted the baculoviral immediate early-1 (ie-1) gene in both a transformed lepidopteran cell line and in the transgenic silkworm Bombyx mori L. Constitutive expression of double-stranded RNA was achieved by piggyBac-mediated transformation of Sf9 cell line with a transgene encoding double-stranded ie-1 RNA (dsie-1). Strong viral repression was seen at early stages of infection but subsequent recovery of viral proliferation was observed. In contrast, the same transgene inserted into the chromosomes of transgenic silkworms induced long-term inhibition of B. mori nucleopolyhedrovirus infection, with nearly 40% protection compared with nontransgenic animals. Protection was efficient at larval stages after oral infection with occlusion bodies or hemocoel injection of budded viruses. Virus injected pupae also displayed resistance. These results show that heritable RNAi can be used to protect silkworm strains from baculovirus infection

The Involvement of SMILE/TMTC3 in Endoplasmic Reticulum Stress Response

The state of operational tolerance has been detected sporadically in some renal transplanted patients that stopped immunosuppressive drugs, demonstrating that allograft tolerance might exist in humans. Several years ago, a study by Brouard et al. identified a molecular signature of several genes that were significantly differentially expressed in the blood of such patients compared with patients with other clinical situations. The aim of the present study is to analyze the role of one of these molecules over-expressed in the blood of operationally tolerant patients, SMILE or TMTC3, a protein whose function is still unknown.We first confirmed that SMILE mRNA is differentially expressed in the blood of operationally tolerant patients with drug-free long term graft function compared to stable and rejecting patients. Using a yeast two-hybrid approach and a colocalization study by confocal microscopy we furthermore report an interaction of SMILE with PDIA3, a molecule resident in the endoplasmic reticulum (ER). In accordance with this observation, SMILE silencing in HeLa cells correlated with the modulation of several transcripts involved in proteolysis and a decrease in proteasome activity. Finally, SMILE silencing increased HeLa cell sensitivity to the proteasome inhibitor Bortezomib, a drug that induces ER stress via protein overload, and increased transcript expression of a stress response protein, XBP-1, in HeLa cells and keratinocytes.In this study we showed that SMILE is involved in the endoplasmic reticulum stress response, by modulating proteasome activity and XBP-1 transcript expression. This function of SMILE may influence immune cell behavior in the context of transplantation, and the analysis of endoplasmic reticulum stress in transplantation may reveal new pathways of regulation in long-term graft acceptance thereby increasing our understanding of tolerance

Heats of adsorption of linearly adsorbed CO species on Co2+ and Co sites of reduced Co/Al2O3 catalysts in relationship with the CO/H-2 reaction

AIR:EAU:SURFACES+JCO:DBIIR spectra in transmission mode are used to measure the heats of adsorption at different coverages theta:E(theta), of two linearly adsorbed CO species formed on Co2+ and Co degrees sites (noted LCo2+ and L-Co degrees) of reduced x% Co/Al2O3 (wt%,x L-Co degrees C (IR band at 2060 cm(-1)) where L-Co degrees C denotes a linear CO species formed on Co degrees sites modified by the C deposition. The heat of adsorption of the L-Co degrees C species varies linearly with its coverage from E-LCo degrees C (1) = 93 kJ/mol to E-LCo degrees C (0) = 165 kJ/mol. In the presence of H-2 with a ratio H-2/CO = 10, the C deposition is strongly decreased and the L-Co degrees species dominates the surface of the cobalt particles. However, in these conditions its hydrogenation into CH4 disturbs its adsorption equilibrium in a large coverage range and only ELCo degrees (1) = 108 kJ/mol has been determined. For a ratio H-2/CO = 3, the carbon deposition cannot be prevented leading to the formation of the L-Co degrees C species. It is shown that the E-LCo degrees C(theta) values are not modified by the presence of adsorbed hydrogen. The heats of adsorption of the different adsorbed CO species on Co degrees sites are consistent with some literature data on DFT calculations and experimental values obtained on model cobalt surfaces (i.e. single crystals). In particular, they confirm DFT calculations which indicate that the C deposition on reduced cobalt particles decreases slightly the heats of adsorption of the linear CO species adsorbed on Co degrees sites. (C) 2012 Elsevier B.V. All rights reserved

Experimental microkinetic approach of the CO/H-2 reaction on Pt/Al2O3 using the Temkin formalism. 1. Competitive chemisorption between adsorbed CO and hydrogen species in the absence of reaction

SSCI-VIDE+ING+DBIInternational audienceExperimental microkineti

Experimental Microkinetic Approach of the Surface Reconstruction of Cobalt Particles in Relationship with the CO/H-2 Reaction on a Reduced 10% Co/Al2O3 Catalyst

AIR:EAU:SURFACES+JCO:DBIThe adsorption of x% CO/He (x = 1 and 2) on a reduced 10 wt % Co/Al2O3 catalyst at an adsorption temperature of 560 K > T-a > 420 K leads to the formation of a linear CO species on Co degrees sites (denoted L-Co degrees species) with an infrared (IR) band at approximate to 2030 cm(-1) at full coverage. This adsorption is associated with the formation of carbon that is implicated in the reconstruction of the surface of the cobalt particles, leading to the progressive transformation of the L-Co degrees species into a new linear CO species on Co degrees C sites of the reconstructed surface with an IR band at approximate to 2060 cm(-1). An experimental microkinetic approach of the reconstruction process via the L-Co degrees -> L-Co degrees C transformation reveals the impact of different kinetic parameters such as the reaction temperature, the CO partial pressure, and the presence of hydrogen. During the reconstruction the coverages of the L-Co degrees and L-Co degrees C species remain very high (>0.95) due to their high heats of adsorption determined by the Adsorption Equilibrium Infra Red spectroscopy method. It is shown that the rate of the reconstruction process is controlled by that of the disappearance of the L-Co degrees species via its dissociation into adsorbed elemental carbon and oxygen species according to a pseudo first kinetic order elementary step involving a small amount of free cobalt sites (approximate to 4 X 10(12) sites/cm(2) of cobalt particles). The impact of the reaction temperature on the L-Co degrees -> L-Co degrees C transformation indicates that (a) the activation energy of the L-Co degrees dissociation which controls the reconstruction process is approximate to 125 kJ/mol and (b) the formation of elemental carbon via the disproportionation of the L-Co degrees species seems unlikely. These two conclusions are consistent with literature data on density functional theory (DFT) calculations. For adsorption temperature >560 K, the formation of superficial graphitic like species overlaps the reconstruction process. In the presence of hydrogen, the reconstruction is observed for H-2/CO ratios <3 but not for higher values (i.e., H-2/CO = 10)

Heats of adsorption of linear CO species adsorbed on reduced Fe/Al2O3 catalysts using the AEIR method in diffuse reflectance mode

AIR:SURFACES+JCO:DBIIR spectra in diffuse reflectance mode are quantitatively exploited to determine the heats of adsorption of two linearly adsorbed CO species formed on Fe2+ and Fe degrees sites (denoted L-Fe(2+) and L-Fe degrees CO species) of reduced x% Fe/Al2O3 (wt%, x = 1 and 5) catalysts according to the AEIR procedure developed previously using the IR transmission mode. The IR transmission properties of iron containing catalysts are limited particularly for high iron loadings favoring the use of the diffuse reflectance mode. The heats of adsorption of the L-Fe(2+) CO species linearly vary with the coverage of the sites from ELFe2+(1) = 45 kJ/mol to EtFe2+(0) = 66 kJ/mol at coverage 1 and 0, respectively. These values are modified by the presence of neither Fe sites nor carbonaceous adsorbed species. The heats of adsorption of the L-Fe degrees. CO species on a C-free iron surface (for adsorption temperature T-a 456 K, the CO dissociation overlaps the CO adsorption equilibrium leading to a C-containing iron surface. The presence of carbonaceous species has no significant impact on the heat of adsorption of the L-Fe degrees species at high coverages whereas it increases significantly that at low coverages: E-LFe degrees(0) = 120 kJ/mol. Considering reduced iron supported catalysts, the AEIR method is particularly useful because it allows the determination of the individual heats of adsorption of two adsorbed CO species that can be simultaneously present on the surface for high iron loadings. The study confirms that quantitative exploitations of DRIFT spectra are available for well designed experimental conditions offering an alternative for solid catalysts with low IR transmission properties. (C) 2011 Elsevier B.V. All rights reserved

Experimental microkinetic approach of the CO/H-2 reaction on Pt/Al2O3 using the Temkin formalism. 2. Coverages of the adsorbed CO and hydrogen species during the reaction and rate of the CH4 production

SSCI-VIDE+ING+DBIInternational audienceExperimental microkineti

Application of the experimental microkinetic approach: case of the Hydrogen Evolution Reaction in gas phase on Pt/TiO2

International @ EAU+JCO:DBI:EPUInternational audienceNon

Synthesis and Characterization of a New Substrate of Photinus pyralis Luciferase: 4-Methyl-D-luciferin

Peer Reviewe

Application of the experimental microkinetic approach: case of the Hydrogen Evolution Reaction on TiO2

International @ EAU+JCO:EPU:DBIInternational audienceSince several years, photocatalysis has been used in many applications such as air and water treatment, whereas Fujushima & Hondas [1] have shown that it could also be used for hydrogen production (HER) from water. However, HER mechanisms are not well known. Experimental microkinetic approach [EMA] could be a powerful tool to answer this question. It has been developed in previous works using the following procedure: (i) proposal of a plausible mechanism of the reaction, (ii) experimental determination of the kinetic parameters of each elementary step, (iii) evaluation of the theorical catalytic activity. This procedure has been firstly applied for the study of the photocatalytic oxidation of isopropyl alcohol [2, 3]. The present study concerns the application of the EMA in the case of the Hydrogen Evolution Reac-tion in presence of vapor pressure of methanol on TiO2