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首页> 外文期刊>Crystal growth & design >In situ observation of dislocations in protein crystals during growth by advanced optical microscopy
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In situ observation of dislocations in protein crystals during growth by advanced optical microscopy

机译：通过高级光学显微镜原位观察生长过程中蛋白质晶体中的位错

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We attempted to visualize defects in a tetragonal lysozyme crystal in situ by laser confocal microscopy combined with differential interference contrast microscopy (LCM-DIM). Birefringence microscopy (BM) and phase-contrast microscopy (PCM) were also employed for the in situ observations. LCM-DIM enabled us to observe the {1 10} surfaces of the crystals and visualize the strain fields around the dislocations normal to a light beam with sufficient contrast during growth for the first time. Relatively large inclusions (60 to 300 mu m) inside the crystal could also be visualized during growth, with the use of BM and PCM. We found that the dislocations appeared in bundles and were probably generated at the periphery of the relatively large inclusions inside the crystal. The existence of the dislocations was confirmed by etching experiments, in which we observed two kinds of etch pits: those with a point bottom and those with a flat bottom; the former corresponded to the dislocations inside the crystal and the latter corresponded to microdefects. Two different critical undersaturations existed above which the point-bottomed and flat-bottomed etch pits started to appear. The critical undersaturation for the point-bottomed etch pits was definitely less than that for the flat-bottomed ones. In the central region of the spiral growth hillock were many point-bottomed etch pits corresponding to the dislocations but not contributing to the formation of spiral growth steps. Although the point-bottomed etch pits were formed in only the central region of the spiral growth hillock, the flat-bottomed ones were randomly formed all over the {110} surfaces.
机译：我们试图通过激光共聚焦显微镜结合微分干涉对比显微镜（LCM-DIM）来可视化四方溶菌酶晶体中的缺陷。双折射显微镜（BM）和相差显微镜（PCM）也用于原位观察。 LCM-DIM使我们能够首次观察到晶体的{1 10}表面，并在生长过程中可视化垂直于光束的位错周围的应变场，并具有足够的对比度。使用BM和PCM，在生长过程中还可以观察到晶体内部相对较大的夹杂物（60至300μm）。我们发现，位错成束出现，并且可能在晶体内部相对较大的夹杂物的外围产生。通过蚀刻实验证实了位错的存在，在该实验中我们观察到两种蚀刻坑：具有点底的蚀刻坑和具有平底的蚀刻坑。前者对应于晶体内部的位错，而后者对应于微缺陷。存在两种不同的临界欠饱和，在其之上开始出现点底和底底刻蚀坑。点底刻蚀坑的临界欠饱和绝对小于平底刻蚀坑。在螺旋生长丘的中心区域有许多点状底部的刻蚀坑，与位错相对应，但无助于螺旋生长步骤的形成。尽管仅在螺旋生长小丘的中心区域形成了点底刻蚀坑，但在{110}的整个表面上都随机形成了平底刻蚀坑。

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