单根青蛙肌纤维椭偏特性的温度效应的初步研究

THE EFFECT OF TEMPERATURE ON SINGLE FORG MUSCLE FIBER STUDIED BY OPTICAL ELLIPSOMETRIC POLARIZATION TECHNIQUE

利用衍射光椭圆偏振参数的变化研究温度(6℃至40℃)对单根青蛙肌纤维内部结构的影响.实验测得,当温度从6℃上升到20℃左右时,衍射光的退偏率r缓慢下降,20℃后r随温度升高而增大,即在20℃左右处出现一双向变化特性;当温度超过30℃后r急剧减小,在30℃附近呈现一极大值.若温度高于35℃左右时,被肌纤维散射的衍射光消失.由此表明温度变化不仅会导致横桥空间取向改变,而且会引起横桥动力学性质的变化;温度过高时,蛋白质分子的热运动会造成肌纤维内部有序结构的破坏.

The polarization properties of light from signle intact relaxed fiber of frog muscle were studied by the ellipsometric spectrometer at the temperature from 6℃ to 40℃ . The depolarization ratio, r, decreased slowly while the temperature increased from 6℃ to 20℃; the r became a minimum value near 20℃, and then in- creased with the temperature continued to increase and reached a maxmum value at 30℃. Beyond 30℃, r decreased quickly, and when the temperature was raised above 35℃, the diffraction pattern disappeard. These phenomena can be explained by the electron micrographs in which the striated structure of the muscle fiber being destroyed at 35℃.So it is considered that the temperature could change the averaged orientation and dynamic properties of the crossbridges within fiber, and that under the high temperature condition, the random thermal motion can cause the structural transition of the fibers from the ordered state to the disordered state.