An Interspecific Nicotiana Hybrid as a Useful and Cost-Effective Platform for Production of Animal Vaccines

The use of transgenic plants to produce novel products has great biotechnological potential as the relatively inexpensive inputs of light, water, and nutrients are utilised in return for potentially valuable bioactive metabolites, diagnostic proteins and vaccines. Extensive research is ongoing in this area internationally with the aim of producing plant-made vaccines of importance for both animals and humans. Vaccine purification is generally regarded as being integral to the preparation of safe and effective vaccines for use in humans. However, the use of crude plant extracts for animal immunisation may enable plant-made vaccines to become a cost-effective and efficacious approach to safely immunise large numbers of farm animals against diseases such as avian influenza. Since the technology associated with genetic transformation and large-scale propagation is very well established in Nicotiana, the genus has attributes well-suited for the production of plant-made vaccines. However the presence of potentially toxic alkaloids in Nicotiana extracts impedes their use as crude vaccine preparations. In the current study we describe a Nicotiana tabacum and N. glauca hybrid that expresses the HA glycoprotein of influenza A in its leaves but does not synthesize alkaloids. We demonstrate that injection with crude leaf extracts from these interspecific hybrid plants is a safe and effective approach for immunising mice. Moreover, this antigen-producing alkaloid-free, transgenic interspecific hybrid is vigorous, with a high capacity for vegetative shoot regeneration after harvesting. These plants are easily propagated by vegetative cuttings and have the added benefit of not producing viable pollen, thus reducing potential problems associated with bio-containment. Hence, these Nicotiana hybrids provide an advantageous production platform for partially purified, plant-made vaccines which may be particularly well suited for use in veterinary immunization programs

Compréhension du corium : séparation de phases entre oxydes et métaux à l’état liquide

National audienc

Influence of powder mixing method on properties of high entropy alloys of FeCrMnAlMo thin coatings obtained by magnetron sputtering

International audienceHigh Entropy Alloys of FeCrMnAlMo thin coatings obtained by magnetron sputtering were studied. The influence of the powder mixing method to obtain the targets used in the physical vapor deposition reactors was evaluated concerning the mechanical and tribological properties of the coatings. The microstructural characterization was also performed. The high purity element powders of 34Fe-22Cr-19Mn-19Al-6Mo were mixed in two ways: mechanically alloyed for 35 h (MS coating) and the other by conventional mixing for 30 min (CM coating). The coatings showed a poorly crystallized structure, almost amorphous. X-ray photoelectron spectrometry results evidenced that the MS coating contains approximately 8 at.% C, while no carbon was detected in the CM coating. The coatings presented hardness values determined by nanoindentation of ~8.7 GPa and 7.4 GPa for MS and CM coatings, respectively. A better reciprocating dry sliding wear resistance with specific wear rate (k) of ~3.33 × 10−5 mm3 N−1 m−1 for MS coating/substrate system was found, while for the CM coating/substrate system was of ~8.23 × 10−5 mm3 N−1 m−1. The abrasive wear mechanism was observed with the formation of ploughing, scratching and debris wear adhered to the alumina counterpart ball

miR-7a regulation of Pax6 controls spatial origin of forebrain dopaminergic neurons.

International audienceIn the postnatal and adult mouse forebrain, a mosaic of spatially separated neural stem cells along the lateral wall of the ventricles generates defined types of olfactory bulb neurons. To understand the mechanisms underlying the regionalization of the stem cell pool, we focused on the transcription factor Pax6, a determinant of the dopaminergic phenotype in this system. We found that, although Pax6 mRNA was transcribed widely along the ventricular walls, Pax6 protein was restricted to the dorsal aspect. This dorsal restriction was a result of inhibition of protein expression by miR-7a, a microRNA (miRNA) that was expressed in a gradient opposing Pax6. In vivo inhibition of miR-7a in Pax6-negative regions of the lateral wall induced Pax6 protein expression and increased dopaminergic neurons in the olfactory bulb. These findings establish miRNA-mediated fine-tuning of protein expression as a mechanism for controlling neuronal stem cell diversity and, consequently, neuronal phenotype