心脏停搏

At the one-cell stage, each embryo was injected with gradient doses of 2-8ng MO. The control morpholino, was purchased from Gene-Tools.To test the knockdown effectiveness of the morpholino, the tbx2-EGFP (enhanced green fluorescent protein) construct was generated. And coinjection of morpholino with mRNA tests its specificity of the morpholino. Overexpression of tbx2 via mRNA microinjection helps us understand gaining function of tbx2. Results The tbx2-EGFP construct tests the knockdown effectiveness of the morpholino. Zebrafish embryos lacking tbx2 function have defects in cardiac contractility, rhythm and morphology in a dose-dependent manner. The embryos with c-MO are normal in development. Coinjection of morpholino with mRNA rescue the phenotype of tbx2 knocking down. The phenotypes include pericardial edema, hypogenetic ventricle, dilation of atria, arrhythmia, bradycardia, asystole, abnormal atrioventricular canal, aberrant valve and blood regurgitation.

结果荧光蛋白融合标记实验验证了tbx2-MO可以很好得阻抑斑马鱼胚胎tbx2的表达，tbx2-MO组胚胎在心脏收缩性、节律和形态学发生上出现了异常，心脏畸形随着注射剂量的增加而出现比较一致的表型，而c-MO组胚胎没有出现明显的畸形；tbx2-mRNA和tbx2-MO的共注射减少了tbx2-MO胚胎心脏畸形的发生率及减轻了心脏畸形的程度，验证了所设计合成的tbx2-MO对tbx2基因的抑制作用具有特异性；tbx2-MO组胚胎心脏缺陷包括心室发育不良、心房扩张、房室管和瓣膜异常以及心率缓慢、心律不齐、心脏停搏、血液返流等，并根据心脏发育异常的程度分为轻、中、重度畸形组tbx2-mRNA基因过表达胚胎没有见到心腔的形成。

The circulation, consumption and reproduction of the trilogy have not only testified to its historical significance and literariness, but also invested it with new meanings.

该三部曲的流通、消费与再生产不仅验证了其历史意义及文学性，而切还赋予它以新的意义。

If he thought that he could buy me off, he would be wrong.

如果他认为他可以收买我，那他就大错特错了。