Institut de biologie

2002, Ceriotti, A., Paris, Nadine, Hillmer, S., Frigerio, L., Neuhaus, Jean-Marc, Vitale, A., Robinson, D. G., Lord, M. E., Davey, J.

1992, Uknes, Scott, Mauch-Mani, Brigitte, Moyer, Mary, Potter, Sharon, Williams, Shericca, Dincher, Sandra, Chandler, Danielle, Slusarenko, Alan, Ward, Eric, Ryals, John

2007, Agne, Birgit, Kessler, Félix

2005, Gouinguene, Sandrine, Pickett, John A, Wadhams, Lester J., Birkett, Michael A, Turlings, Ted

Many parasitic wasps are attracted to volatiles that are released by plants when attacked by potential hosts. The attractiveness of these semiochernicals from damaged plants has been demonstrated in many tritrophic systems, but the physiological mechanisms underlying the insect responses are poorly understood. We recorded the antennal perception by three parasitoids (Cotesia marginiventris, Microplitis rufiventris, and Campoletis sonorensis) to volatiles emitted by maize, cowpea, and cotton plants after attack by the common caterpillar pest Spodoptera littoralis. Gas chromatography-electroantennography (GC-EAG) recordings showed that wasps responded to many, but not all, of the compounds present at the physiologically relevant levels tested. Interestingly, some minor compounds, still unidentified, elicited strong responses from the wasps. These results indicate that wasps are able to detect many odorant compounds released by the plants. It remains to be determined how this information is processed and leads to the specific behavior of the parasitoids.

2001, Di Sansebastiano, Gian Pietro, Paris, Nadine, Marc-Martin, Sophie, Neuhaus, Jean-Marc

Protein trafficking to two different types of vacuoles was investigated in tobacco (Nicotiana tabacum cv SR1) mesophyll protoplasts using two different vacuolar green fluorescent proteins (GFPs). One GFP is targeted to a pH-neutral vacuole by the C-terminal vacuolar sorting determinant of tobacco chitinase A, whereas the other GFP is targeted to an acidic lytic vacuole by the N-terminal propeptide of barley aleurain, which contains a sequence-specific vacuolar sorting determinant. The trafficking and final accumulation in the central vacuole (CV) or in smaller peripheral vacuoles differed for the two reporter proteins, depending on the cell type. Within 2 d, evacuolated (mini-) protoplasts regenerate a large CV. Expression of the two vacuolar GFPs in miniprotoplasts indicated that the newly formed CV was a lytic vacuole, whereas neutral vacuoles always remained peripheral. Only later, once the regeneration of the CV was completed, the content of peripheral storage vacuoles could be seen to appear in the CV of a third of the cells, apparently by heterotypic fusion.

2010-12-3, Parisod, Christian

2014, Berggoetz, M, Schmid, M, Ston, D, Wyss, V, Chevillon, Christophe, Pretorius, A-M, Gern, Lise

2015-12, Jacquet, Maxime, Durand, Jonas, Rais, Olivier, Voordouw, Maarten

Cross-reactive acquired immunity in the vertebrate host induces indirect competition between strains of a given pathogen species and is critical for understanding the ecology of mixed infections. In vector-borne diseases, cross-reactive antibodies can reduce pathogen transmission at the vector-to-host and the host-to-vector lifecycle transition. The highly polymorphic, immunodominant, outer surface protein C (OspC) of the tick-borne spirochete bacterium Borrelia afzelii induces a strong antibody response in the vertebrate host. To test how cross-immunity in the vertebrate host influences tick-to-host and host-to-tick transmission, mice were immunized with one of two strain-specific recombinant OspC proteins (A3, A10), challenged via tick bite with one of the two B. afzelii ospC strains (A3, A10), and infested with xenodiagnostic ticks. Immunization with a given rOspC antigen protected mice against homologous strains carrying the same major ospC group allele but provided little or no cross-protection against heterologous strains carrying a different major ospC group allele. There were cross-immunity effects on the tick spirochete load but not on the probability of host-to-tick transmission. The spirochete load in ticks that had fed on mice with cross-immune experience was reduced by a factor of two compared to ticks that had fed on naive control mice. In addition, strain-specific differences in mouse spirochete load, host-to-tick transmission, tick spirochete load, and the OspC-specific IgG response revealed the mechanisms that determine variation in transmission success between strains of B. afzelii. This study shows that cross-immunity in infected vertebrate hosts can reduce pathogen load in the arthropod vector with potential consequences for vector-to-host pathogen transmission. (C) 2015 Elsevier B.V. All rights reserved.

2004, Schiff Giovannini, Isabelle, Job, Daniel, Hmamda, Abdelaziz

2012, Salwiczek, Lucie, Pretot, Laurent, Demarta, Lanila, Proctor, Darby, Essler, Jennifer, Wismer, Sharon, Stoinski, Tara, Brosnan, Sarah F., Bshary, Redouan