Chemistry Department, Christopher Ingold Laboratories, University College London, 20 Gordon Street, London, WC1H 0AJ, UK.
Survivability and Advanced Materials group, Centre for Defence Engineering, Cranfield University at the Defence Academy of the UK, Shrivenham, SN6 8LA, UK.
Sci Rep. 2019 Jun 18;9(1):8716. doi: 10.1038/s41598-019-44704-3.
Following observations of survival of microbes and other life forms in deep subsurface environments it is necessary to understand their biological functioning under high pressure conditions. Key aspects of biochemical reactions and transport processes within cells are determined by the intracellular water dynamics. We studied water diffusion and rotational relaxation in live Shewanella oneidensis bacteria at pressures up to 500 MPa using quasi-elastic neutron scattering (QENS). The intracellular diffusion exhibits a significantly greater slowdown (by -10-30%) and an increase in rotational relaxation times (+10-40%) compared with water dynamics in the aqueous solutions used to resuspend the bacterial samples. Those results indicate both a pressure-induced viscosity increase and slowdown in ionic/macromolecular transport properties within the cells affecting the rates of metabolic and other biological processes. Our new data support emerging models for intracellular organisation with nanoscale water channels threading between macromolecular regions within a dynamically organized structure rather than a homogenous gel-like cytoplasm.
在观察到微生物和其他生命形式在深地下环境中的存活后，有必要了解它们在高压条件下的生物功能。细胞内水动力学决定了生化反应和运输过程的关键方面。我们使用准弹性中子散射 (QENS) 在高达 500 MPa 的压力下研究了活的希瓦氏菌属（Shewanella oneidensis）细菌中的水扩散和旋转松弛。与用于重悬细菌样品的水溶液中的水动力学相比，细胞内扩散显示出明显更大的减速（-10-30%）和旋转松弛时间的增加（+10-40%）。这些结果表明，细胞内的离子/大分子运输特性的压力诱导粘度增加和减速会影响代谢和其他生物过程的速率。我们的新数据支持细胞内组织的新兴模型，其中纳米级水通道在动态组织结构内的大分子区域之间形成，而不是均匀的凝胶状细胞质。
