Pezolet M, Pigeon-Gosselin M, Savoie R, Caille J P
Biochim Biophys Acta. 1978 Dec 1;544(2):394-406. doi: 10.1016/0304-4165(78)90107-1.
Laser Raman spectroscopy has been used to investigate the state of water in intact single muscle fibers of the giant barnacle (Balanus nubilus). The spectra in the region of the O-H (or O-2H) stretching modes of water in unfrozen fibers show that there is no appreciable difference between the shape and relative intensity of the Raman bands due to the water molecules located inside a muscle fiber and those of the corresponding bands in the spectrum of pure water. The presence of significant amounts of "structured" intracellular water, greater than approx. 5% of the total water content, in these fibers is thus excluded. The Raman spectra of frozen fibers have also been recorded in order to evaluate the amount of intracellular water which remains unfrozen at temperatures below the normal freezing point of water. We have been able to reproduce these spectra by assuming that the spectrum of a frozen fiber is the sum of the individual spectra of water and ice. To calculate the amount of unfrozen water from these curve fittings, it was also necessary to determine the intensities of the water and ice Raman bands relative to one another. We have found the I(ice)/I(water) ratio is 1.07 +/- 0.01 for H2O and 1.05 +/- 0.03 for 2H2O With these figures, we have calculated that for a fiber with a normal water content of 80%, 20% of the water molecules remain in the supercooled state of -5 degrees C, which corresponds to 1 g of water per g of fiber dry weight. This amount of bound water was also found to be independent of the water content of the fibers.
激光拉曼光谱已被用于研究巨型藤壶（Balanus nubilus）完整单肌纤维中的水状态。未冷冻纤维中水分子O-H（或O-2H）伸缩振动模式区域的光谱表明，肌纤维内水分子产生的拉曼带的形状和相对强度与纯水光谱中相应谱带的形状和相对强度之间没有明显差异。因此，排除了这些纤维中存在大量“结构化”细胞内水（大于总含水量的约5%）的情况。还记录了冷冻纤维的拉曼光谱，以评估在低于水的正常冰点的温度下仍未冻结的细胞内水的量。我们能够通过假设冷冻纤维的光谱是水和冰的各个光谱之和来重现这些光谱。为了从这些曲线拟合中计算未冻结水的量，还需要确定水和冰拉曼带彼此之间的强度。我们发现，对于H2O，I(冰)/I(水) 比率为1.07±0.01，对于2H2O为1.05±0.03。根据这些数据，我们计算出，对于正常含水量为80%的纤维，20%的水分子保持在-5摄氏度的过冷状态，这相当于每克纤维干重1克水。还发现这种结合水的量与纤维的含水量无关。
