光捕捉活细胞染色体

本文综合报道了作者近数年来以PTK_2细胞为实验材料,用Nd:YAG激光器所发射的1.06微米波长和氩离子泵浦Titanium-Sapphire激光所发射的700—760毫微米波长的连续激光微光束作为光捕捉在显微操作染色体方面的一些主要实验结果。所得结果表明光捕捉可诱发中期细胞的落后染色体向中期板加速移动,抓住后期细胞的一对染色体,使其停留在中期板保持静止不动,而其余的染色体对照常进行染色单体的分离並移向两极,在后期一直用光捕捉抓住的那对染色单体,最终在胞质分裂时将进入一个子细胞,或丢失在分裂沟中或两染色单体分开,各自分别进入原相对的子细胞。作为光捕捉Titanium-Sapphire激光器发射的700—760毫微米波长的激光束,比Nd:YAG激光的1.06微米波长能在更高的输出能量水平下操作而产生较小的对细胞损伤的副作用,从而更容易操作染色体。在适宜的输出能量水平下操作,光捕捉不会对细胞造成损伤,受光捕捉的细胞一般都能继续分裂直至形成两个子细胞。实验结果证明光捕捉技术是一项研究活细胞纺锤体、染色体运动等细胞生物学问题而又不损伤细胞的良好工具。光捕捉技术也可能对诱发单体、三体细胞,研究细胞遗传提供新的手段。

OPTICAL TRAPPING OF CHROMOSMES IN LIVING CELLS

Experimental results involving micromanipulation of chromosomes by an optical trapping force created by a 1060 nm Neodyniurn YAG laser or a 700-760nm titanium-sapphire laser were reported in this paper. When optical forces were applied to the late moving metaphase chromosomes, the trapped choromosomes initiated movement with rapid velocity to the metaphase plate.At the initiation of anaphase,a pair of chromatids could be held by the optical trap and kept motionless at the equatorial plate throughout anaphase,while the other pairs of chromatids separated and moved to opposite spindle poles. As a result, the trapped chromosome was either incorporated into one of the daughter cells or lost in the cleavage furrow, or the two chromatids eventually separated and moved to their respective daughter cells. However, the titanium-sapphire laser - induced force was a much stronger trap in the manipulation of chromosomes, and the side effect of cell damage was less in comparision with of the YAG laser.When desirable energy dosages were applied,the survival rate of trap ped cells, indicated by undergoing further division to the formation of two daughter cells,was high,regardless of the elongation of mitosis.It was demonstrated that the optical trap is a potential tool for noninvasive study of mitotic spindle and chromosome movement of living cells, and it is also a new technique for inducing monosomy and trisomy in cell genetics.