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Chaperones and hydrostatic pressure

Chaperones and hydrostatic pressure

 Chaperones and hydrostatic pressure

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Cario et al., 2016, Scientific Reports.

Cario et al., 2016. Molecular chaperone accumulation as a function of stress evidences adaptation to high hydrostatic pressure in the piezophilic archaeon Thermococcus baroptilus. Scientific Reports 6, doi:10.1038/srep29483

Amongst deep-biosphere ecosystems, hydrothermal vents are one of the most intriguing. Upon release in the ocean, the hot, reduced hydrothermal vent fluid gets into contact with the cold, oxidized ocean waters, creating a very sharp gradient in temperature, salinity, and redox potential over a few centimeters. Thus, it is expected that microorganisms from hydrothermal vents express a strong stress adaptation in order to survive these extreme polystresses. We have monitored the accumulation of osmolytes as a function of thermal, salinity and pressure stress in Thermococcus barophilus, a hyperthermophilic, piezophilic archaeon. We demonstrated that this species accumulated mannosyl-glycerate (MG) primarily in response to salinity stress, but also in response to thermal and low pressure stress. MG accumulation peaked for combined stresses. The accumulation of MG was drastically increased under sub-optimal hydrostatic pressure conditions, demonstrating that low pressure is perceived as a stress in this piezophile, and that the proteome of T. barophilus is low-pressure sensitive. MG accumulation was strongly reduced under supra-optimal pressure conditions clearly demonstrating the structural adaptation of this proteome to high hydrostatic pressure. These results constitute the first experimental proof of a structural adaptation to high hydrostatic pressure in a piezophile. Furthermore, our observations suggest that the stress response in T. barophilus may be under negative selective pressure.

Voir en ligne : Cario et al. @ Nature