Section: New Results

Analysis of lateral organization of ordered domains at the plasma membrane surface

Participant : Charles Kervrann.

Modifications of plasma membrane physical properties are also known to be involved in the perception and response to environmental modifications such as temperature, mechanical and osmotic stress in various organisms. We have analysed a recently designed probe, di-4-ANEPPDHQ, that can change its fluorescent properties depending on whether it is residing in ordered or disordered phases of the tobacco cell plasma membranes. We performed a spatial analysis (covariograms, Markov Random Fields) of small (<200 nm) ordered domains observed in multispectral confocal microscopy. We focused on binary images, assumed to be realizations of a MRF-Ising model, depicting the spatial organization of ordered domains. Maximum pseudo-likelihood methods were investigated to estimate parameters able to describe the spatial properties of ordered domains. We analyzed the modifications of the whole plasma membrane fluidity, and the distribution of ordered domains occurring in the few minutes following addition of the elicitor of defense reaction cryptogein to tobacco cells.

Partners: P. Gerbeau-Pissot, F. Simon-Plas (UMR 1088 PME INRA, Dijon) and K. Kiêu (MIA Unit INRA, Jouy-en-Josas)