Tabony J, Job D
Département de Biologie Moléculaire et Structurale, B.R.C.E.-C.S., Centre d'Etudes Nucléaires, Grenoble, France.
Nature. 1990 Aug 2;346(6283):448-51. doi: 10.1038/346448a0.
Microtubules are believed to be the principal organizers of the cell interior. Cells respond to a variety of stimuli by modifying the spatial distribution of the microtubules. These effects are central to cell division and morphogenesis, and embryo development. During embryo development, macroscopic patterns are frequently observed. Here we report that microtubular solutions spontaneously form alternating white and dark stripes about 1 mm wide and 1 cm long. Small-angle neutron scattering measurements show that in each segment the microtubules are aligned obliquely to the direction of the stripe, and that the white and dark stripes differ in having mutually orthogonal orientations. The formation of these structures requires an initial reservoir of organic phosphate. Phosphorus NMR measurements show that the process is accompanied by the energy-liberating conversion of organic to inorganic phosphate. These observations, together with similarities to the dissipative spatial structure formed by the Belousov-Zhabotinski reaction, provide strong evidence that the observed structures are energy-dissipative in nature. Dissipative structures are thought to be critical to the appearance of complex living organisms. Our results strongly suggest that microtubules are capable of forming such structures. Microtubular dissipative structures may occur during mitosis and embryo morphogenesis.
微管被认为是细胞内部的主要组织者。细胞通过改变微管的空间分布来响应各种刺激。这些效应对于细胞分裂、形态发生和胚胎发育至关重要。在胚胎发育过程中，经常会观察到宏观图案。在此我们报告，微管溶液会自发形成宽度约1毫米、长度约1厘米的黑白相间的交替条纹。小角中子散射测量表明，在每个条纹段中，微管与条纹方向倾斜排列，并且黑白条纹在相互正交的取向上有所不同。这些结构的形成需要有机磷酸盐的初始储备。磷核磁共振测量表明，该过程伴随着有机磷酸盐向无机磷酸盐的能量释放转化。这些观察结果，连同与贝洛索夫-扎博廷斯基反应形成的耗散空间结构的相似性，提供了有力证据，证明所观察到的结构本质上是能量耗散的。耗散结构被认为对于复杂生物体的出现至关重要。我们的结果强烈表明微管能够形成这样的结构。微管耗散结构可能在有丝分裂和胚胎形态发生过程中出现。
