Smith L, Hochmuth R M
J Cell Biol. 1982 Jul;94(1):7-11. doi: 10.1083/jcb.94.1.7.
The elasticity and viscosity of the human erythrocyte membrane were measured as a function of the concentration of wheat germ agglutinin (WGA) in a suspending solution containing 1 mg/ml albumin, approximately 5 X 10(5) cells/ml and between 0.0 and 0.2 microgram/ml WGA. Membrane elasticity was characterized by the elastic shear modulus, which provided a measure of the resistance of the membrane to constant-area elastic deformations that occurred in the membrane plane. The elastic shear modulus was determined by aspirating a portion of the membrane into a micropipette and measuring the extension of the membrane into the pipette as a function of the suction pressure. The results indicated no significant change in shear modulus for concentrations of WGA between 0.0 and 0.2 microgram/ml. Membrane viscosity was characterized by the coefficient of surface viscosity, which, in effect, was a measure of the membrane's resistance to rates of deformation. This coefficient was determined from the time required for an erythrocyte to recover its undeformed shape after it had been elongated by the application of an equal and opposite force applied at diametrically opposite points on the erythrocyte rim. The value for the coefficient of surface viscosity was found to increase by a factor of almost three when the WGA concentration was increased from 0.0 to 0.2 microgram/ml. These results indicated that, in the presence of albumin, WGA can increase membrane dissipation (viscosity) without altering the structural rigidity (elasticity) of the membrane.
在含有1mg/ml白蛋白、约5×10⁵个细胞/ml且WGA浓度在0.0至0.2μg/ml之间的悬浮溶液中，测定了人红细胞膜的弹性和粘度。膜弹性通过弹性剪切模量来表征，该模量提供了膜对膜平面内发生的等面积弹性变形的阻力的度量。弹性剪切模量是通过将一部分膜吸入微量移液器，并测量膜进入移液器的延伸量作为抽吸压力的函数来确定的。结果表明，WGA浓度在0.0至0.2μg/ml之间时，剪切模量没有显著变化。膜粘度通过表面粘度系数来表征，实际上，它是膜对变形速率的阻力的度量。该系数是根据红细胞在其边缘相对两点施加大小相等、方向相反的力而被拉长后恢复其未变形形状所需的时间来确定的。当WGA浓度从0.0增加到0.2μg/ml时，发现表面粘度系数的值增加了近三倍。这些结果表明，在白蛋白存在的情况下，WGA可以增加膜的耗散（粘度）而不改变膜的结构刚性（弹性）。
