■  细胞质膜上的内陷结构与功能研究

真核细胞的细胞质膜是一个不均一体系，包含大量脂类组成和生物物理特性不同的区域。这些蛋白脂类区域使质膜产生内陷，而内陷在胞吞过程中起重要作用。在这些质膜区域中，网格蛋白包被的小窝(clathin coated pits, CCP)和胞膜窖(caveolae)由于表面有明显的蛋白包被，很容易用电镜成像等方法观测到。CCP呈80-120 nm的球形结构，包被有网格蛋白和衔接蛋白。网格蛋白调控的内吞作用通路(CME)通过被膜小窝实现胞吞。Caveolae是50-80 nm的内陷结构，在信号转导，膜运输，胆固醇运输，机械传感等过程中起作用，在受到机械应力作用的细胞，如脂肪细胞，内皮细胞和肌细胞中含量较高。有研究发现了小凹的产生及与胞内体的融合，但Caveolae是否在胞吞中起作用尚无定论。

在下图的实例中，研究人员使用了Abbelight的成像3D单分子荧光成像系统-SAFe 360分辨出了内皮细胞中的Clathrin和Caveolae。结果显示了清晰、无重叠的荧光分布，与电镜成像结果一致。

图1. Abbelight SAFe360系统重现质膜上蛋白脂类区域的蛋白分布

图2. 通过SAFe360的同时多色成像功能可以清晰、无重叠地区分Clathrin 和Caveolae，进一步研究Clathrin 和Caveolae的内吞作用通路的相互关系。

■  大肠杆菌RNA聚合酶的空间分布与动力学研究

大肠杆菌中的RNA聚合酶(RNAP)空间上呈拟核形状分布，是核糖体RNA(rRNA)的转录中心。下方实例使用Abbelight SAFe 360系统通过PALM超分辨成像与单分子追踪(sptPALM)解析大肠杆菌RNAP的纳米尺度空间分布与动力学，进而研究转录调控机制。

图1. (A)Denndra2标记RNAP在大肠杆菌中分布定位(定位精度约为15 nm)；（B）通过DBSCAN算法对大肠杆菌中RNA聚合酶分布进行团簇分析。

图2. 在活细胞中以200 FPS(5 ms/帧)的采集速度对大肠杆菌中Dendra2标记的RNAP分子进行单分子追踪以研究单个RNAP分子运动轨迹，按照运动状态分为静态(红色，即转录中)或动态(紫色，扩散运动)。

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