培養体細胞の分裂前期における核膜崩壊 : 位相差顕微鏡による観察

With a technique of phase-contrast, time-lapse cinematography, the breakdown of nuclear envelope in cultured newt lung cells was analysed from the selected film sequences. Prophase chromosomes showed a centrifugal movement in the nuclear cavriy during about 20 to 30 minutes prior to the nuclear envelope breakdown. The first visible alteration indrcating the breakdown at the end of prophase was a conspicuous dent of the membrane. A small break was seen in this area where the centrioles were supposed to be orrented. Then the envelope disrupted into larger segments after the invaginated portion of the membrane ruptured. The disruption extended over other segments of the envelope gradually, which proceeded for about 6 to 12 minutes from the initiation of breakdown. The result indrcated that the nutral point always oriented perpendicularly to the equatorial plate of the metaphase.