This study investigated how water management occurs inside organisms without a nucleus (prokaryotes), and how dissolved ions, metabolites and macromolecular species would affect the mobility and transport properties of water in a macromolecular environment containing these molecules.  

The research collaboration studied the diffusion and rotational relaxation of water in live Shewanella oneidensis bacteria at pressures up to 500 MPa using quasi-elastic neutron scattering (QENS). They found that the intracellular water dynamics exhibit significantly greater slowdown compared with bulk water and aqueous electrolyte solutions of compositions comparable to cytoplasm.  

Classic interpretations of prokaryotes present the intracellular cytoplasm as a gel-like medium containing dissolved ions and macromolecules such as lipids and proteins. However, the findings suggest a more structured internal environment, with cooperatively organised “superclustered" arrangements of proteins and macromolecular complexes, separated by channels enabling transport of the water-based electrolyte solution. 

The pressure-induced viscosity increase and slowdown in ionic/macromolecular transport properties within the cells affect the rates of metabolic and other biological processes. The findings of this investigation lend further support to emerging models for intracellular organisation that could lead to new insights into biological functioning of organisms under ambient and high pressure conditions. ​

Instrument: IRIS ​