
TY  - JOUR
A1  - Walter, JA 
A1  - Hope, AB 
T1  - Proton Magnetic Resonance Studies of Water in Slime Mould Plasmodia
JF  - Australian Journal of Biological Sciences
JO  - Aust. Jnl. Of Bio. Sci.
Y1  - 1971
VL  - 24
IS  - 3
SP  - 497
EP  - 508
KW  - 
UR  - https://doi.org/10.1071/BI9710497 
N2  - Steady-state and pulse n.m.r. techniques have been applied in a study of water  in the cytoplasm of slime mould plasmodia (Ph;ysarum polycephalum). The former  method has been used to confirm that the signal detected was from protons in water  molecules, and to estimate the fraction of the total water in the sample that was  contributing to the observed signal. Pulse techniques have enabled direct measurement  of the self-diffusion coefficient D of the bulk water in the cytoplasm, and the  proton spin-lattice and spin-spin relaxation times Tl and T2 respectively. The  measurements of D can be accounted for if most of the water is in a "free" state,  similar to water in a dilute ionic solution, but with a lower value of D due to the  obstruction effect of macromolecules and cytoplasmic structures. The values of Tl  and T2 indicate that a small "bound" fraction of the water molecules has more  restricted motion. The assumption of a two-state model, with exchange of water  molecules between "free" and "bound" phases in a time ~ 10-3 sec, yields a representative  correlation time T "'" 10-8 sec for the bound fraction. This model is the  simplest compatible with all the above results. The underlying assumptions, the  extent to which it is likely to be an approximation, and the implications regarding  some theories of cellular functions are discussed. Similar results have also been  obtained from samples of toad leg muscle, ceils from the meristematic region of pea  roots, and from agar and gelatin gels. 
ER  -

