Germain D, Maysinger D, Glavinovic M I
Department of Computer Engineering, McGill University, Montreal, Canada.
J Neurosci Methods. 2006 May 15;153(1):27-42. doi: 10.1016/j.jneumeth.2005.10.003. Epub 2005 Nov 14.
The principal goals of this study were to establish a quantitative morphological analysis of spatial and regional properties of dense core vesicles, and to use this analysis to assess whether homotypic fusion is prominent in chronically treated PC-12 cells at elevated release levels. Simple computerized image processing of electron-micrographs provided the binary images of vesicular dense cores, whilst the artificial intelligence methods were needed to determine the vesicular membranes. As in the past, the presence of large, highly irregular vesicles, provided the morphological evidence of fused vesicles, but the irregularity of vesicular shape was assessed quantitatively-from its roundness. Free space of each vesicle was determined from the distance to its nearest-neighbor, or from the size of its Voronoi polygon. Within a Voronoi polygon, each point is closer to that vesicle than to any other vesicle. Large vesicles were not less round and did not have larger free space, as expected if they result from fusion of several smaller vesicles. In conclusion, we present a novel and rigorous morphological analysis of spatial and regional properties of dense core vesicles. The results demonstrate that the homotypic fusion is not prominent in PC-12 cells, before or following a chronic treatment that enhances release.
本研究的主要目标是建立对致密核心囊泡的空间和区域特性的定量形态学分析，并利用该分析评估在释放水平升高的长期处理的PC-12细胞中同型融合是否显著。电子显微镜图像的简单计算机图像处理提供了囊泡致密核心的二值图像，而确定囊泡膜则需要人工智能方法。与过去一样，大的、高度不规则的囊泡的存在提供了融合囊泡的形态学证据，但囊泡形状的不规则性是通过其圆度进行定量评估的。每个囊泡的自由空间是根据到其最近邻的距离或其Voronoi多边形的大小来确定的。在一个Voronoi多边形内，每个点到该囊泡的距离比到任何其他囊泡的距离更近。大囊泡并不比预期的更不圆，也没有更大的自由空间，如果它们是由几个较小的囊泡融合而成的话。总之，我们提出了一种新颖且严谨的致密核心囊泡空间和区域特性的形态学分析。结果表明，在增强释放的慢性处理之前或之后，PC-12细胞中的同型融合并不显著。
