Molecular chaperone accumulation as a function of stress evidences adaptation to high hydrostatic pressure in the piezophilic archaeon Thermococcus barophilus

Abstract

The accumulation of mannosyl-glycerate (MG), the salinity stress response osmolyte of Thermococcales, was investigated as a function of hydrostatic pressure in Thermococcus barophilus strain MP, a hyperthermophilic, piezophilic archaeon isolated from the Snake Pit site (MAR), which grows optimally at 40 MPa. Strain MP accumulated MG primarily in response to salinity stress, but in contrast to other Thermococcales, MG was also accumulated in response to thermal 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. The lack of MG synthesis only slightly altered the growth characteristics of two different MG synthesis deletion mutants. No shift to other osmolytes was observed. Altogether our observations suggest that the salinity stress response in T. barophilus is not essential and may be under negative selective pressure, similarly to what has been observed for its thermal stress response.

High protein flexibility and reduced hydration water dynamics are key pressure adaptive strategies in prokaryotes

“…Consistent with this hypothesis, T. barophilus cells were shown to express stress proteins at ambient pressure57. This view is further supported by the piezophysiology study of Cario et al 58. which clearly shows that under low pressure conditions, T. barophilus cells accumulate the small organic osmolyte, mannosyl-glycerate (MG).…”

Stability of the chaperonin system GroEL–GroES under extreme environmental conditions

“…Moreover, stress-induced denaturation of proteins can be counteracted by the chaperonin's support of correct refolding. [1][2][3][4] Here, we investigated the effect of temperature and pressure stress on the conformational stability of the heat shock protein (Hsp) complex GroEL-GroES of Escherichia coli (Fig. 1a), which belongs to the group I chaperonins.…”

The effect of O2 and pressure on thiosulfate oxidation by Thiomicrospira thermophila

“…Moreover, the effect of high hydrostatic pressure on growth and metabolism is less frequently investigated due to the difficulties involved in the experimental design (Takai et al, 2008). For example, previous studies of piezophilic micro-organisms have suggested that energy production and central metabolism-related genes appear to be overexpressed under high hydrostatic pressures (Amrani et al, 2014;Cario, Jebbar, Thiel, Kervarec, & Oger, 2016;Michoud & Jebbar, 2016;Pradel et al, 2013;Vannier, Michoud, Oger, Marteinsson, & Jebbar, 2015). A recent study involving high-pressure culturing of a piezophilic and chemolithoautotrophic epsilonproteobacterium (Nautilia sp.…”