Variability of venom components in immune suppressive parasitoid wasps: From a phylogenetic to a population approach

International audienceEndoparasitoid wasps develop at the expense of other insects, leading to their death. Eggs deposited inside the host body induce an immune response, which results in the formation of a melanized cellular capsule around the egg. To evade or counteract this response, endoparasitoids have evolved different strategies, the most often reported being injection into the host of immunosuppressive factors, notably venom proteins, along with the egg. The analysis of venom components has been performed independently in species of different taxa, but the present picture is far from complete. Intriguingly, the question of the level of venom variability inside species has been neglected, although it may partly determine the potential for parasitoid adaptation. Here, we present a short review of our present knowledge of venom components in endoparasitoids, as well as of the only well-known example of intraspecific variability in a venom immune suppressive protein being responsible for variation in parasitoid virulence. We then present data evidencing inter-individual variation of venom protein profiles, using a gel electrophoresis approach, both in laboratory strains and field populations of a figitid and a braconid species. Whether occurrence of such variability may permit a selection of parasitoid venom components driven by the host remains to be tested, notably in the context of the production and use of biological control auxiliaries

Characteriasation for Numerical Study of Mechanical Behaviour of Cermet Mo-Tic

International audienc

Microstructural characterization of a composite Mo reinforced by 25 at.% TiC

International audienceIn the scope of cermet development for structural pieces of future nuclear reactors (1000-1650 degrees C), Mo-TiC(25at.%) was processed by hot isostatic pressure (HIP) and characterized in term of microstructure and chemical composition. The fabrication resulted in a three-phase material so called core/shell microstructure. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) analyses, both coupled with X-ray detection (EDX), allowed to highlight the formation of TiC-Mo(15at.%) phase at the TiC/Mo interface, in agreement with the phase diagram. The formation mechanisms of this phase are discussed. (C) 2009 Elsevier B.V. All rights reserved