In the past, neutron experiments performed on bacteria and purified proteins proved to be successful in quantifying the extent to which macromolecular dynamics is affected by adaptation to extreme temperatures (Tehei et al., 2004 and 2005). Dynamics fluctuations and force constants were found by recording elastic incoherent neutron scattering on IN13. High pressure conditions prevail in a vast part of the biosphere. The existence of a pressure adaptation at the molecular dynamics level is still not established. To address this question, we will explore the effects of hydrostatic pressure on the macromolecular dynamics of different microorganisms originated from surface and deep sea environments. The intact cells will be exposed to high pressure within the sample holder in the domain between 0 and 1200 bar. Lyzed cells samples will also be measured under high pressure. Indeed, intracellular crowding conditions are expected to contribute to the stabilization of macromolecular structure and might therefore hamper the detection of high-pressure effects on protein intracellular dynamics.