Effects of Trehalose on the Water Structure in Yeast Cells as Studied by <i>in vivo</i> 1H NMR Spectroscopy

Abstract

Abstract Trehalose-containing and -lacking yeast cells are prepared, and in vivo 1H NMR spectra are measured in order to investigate effects of this sugar on water structure in the cells. The T2 relaxation times for the intracellular water protons are measured as a function of water content in the yeast cells. The results indicate that the intracellular water is categorized into at least two groups: highly immobilized water (T2 5 ms), assigned to bound water, and intermediate water. One of the most important findings is that the relative population of bound water is drastically increased by the accumulation of trehalose. About 80% of the intracellular water in the trehalose-containing yeast cells is attributed to bound water. Similar results are obtained for trehalose-containing and -lacking model membranes prepared from dipalmitoylphosphatidylcholine (DPPC). Additionally, DSC measurements are carried out to examine effects of trehalose on the gel–liquid crystalline transition temperature of the DPPC membranes. On the basis of these results, a brief discussion is given about the role of trehalose as a stress tolerance-inducer in cells.