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

HIRA, a molecule of the egg which controls the formation of the male pronucleus.

National audienc

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

Peer Reviewe

Quantitative analysis of infrared spectra of adsorbed species using transmission and diffuse reflectance modes Case study: Heats of adsorption of CO on TiO2 and CuO/Al2O3

Couble, Julien Gravejat, Paul Gaillard, Francois Bianchi, DanielIR spectroscopy in transmission and in diffuse reflectance modes is used to characterize the adsorbed CO species formed during the adsorption of CO on (a) a TiO2 solid and (b) a partially reduced CuO/Al2O3 solid. The experiments consist studying the evolution of the intensities of the characteristic IR bands with the adsorption temperature T-a at a constant adsorption pressure P-a. For the two IR analytical procedures, the spectra are used to measure the heats of adsorption of the adsorbed CO species on the two solids according to the AEIR procedure previously described using the IR transmission mode. This allows us to fix the experimental conditions allowing a quantitative analysis of the IR spectra recorded in diffuse reflectance. Mainly, it is shown that the relative reflectance at the position of the characteristic IR bands of the adsorbed CO species must be higher than a critical value during the measurements. According to the amount of adsorbed species, this can be achieved by the dilution of the catalyst with another material that does not contribute to the experimental data. In the present study, it is shown that TiO2 and CuO/Al2O3 can be used without and with dilution respectively. For the Cu/Al2O3 catalyst, the alumina support has been used for the dilution whereas KBr that exhibits acceptable optical properties leads to a significant modification of the heats of adsorption of the adsorbed CO species. This study suggests that heats of adsorption of adsorbed species formed on catalysts of low IR transmission can be determined by the AEIR method using the diffuse reflectance mode. This offers a way to extend the application of quantitative analysis of IR spectra of adsorbed species (i.e. AEIR method) to solid of low IR transmission in particular the industrial catalysts. (C) 2009 Elsevier B.V. All rights reserved