Gold - software tools for ultrastructural studiesElectron microscopy (EM) is the method of choice to study subcellular compartments in biological samples with high resolution. In many cases, the cellular compartments are defined by the content of specific molecules or by a presence of specific functions and they are morphologically inconspicuous in EM preparations. Such compartments can be detected using antibodies with attached label, usually gold particles. In this case, however, it is necessary to delineate the borders of the immunogold clusters in order to define the topology of the compartment. However, the labeling has a point pattern, while a compartment is a coherent area. In addition, some background labeling is always present which complicates identification of the labeled compartments. Stereological image analysis is therefore required to interpret the density distribution of gold particles.
Originally, we developed for the evaluation of colocalization and clustering patterns an independent computer program "Gold", which runs as a self-standing program under Windows 95/98/2000/NT 4.0. However, we do not maintain this program anymore as Windows upgrades produce more and more errors while the program runs. Also, it was necessary to define first the coordinates of gold particles using some other image-processing software (e.g. Adobe Photoshop or Lucia).
We recommend therefore to use the Ellipse plug-ins described below.
The “Gold” plug-ins for the commercially available "Ellipse" program allow the researcher to detect gold particles in an EM image and then either (1), to delineate the borders of cellular compartments, which are defined by the content of specific molecules or by a presence of specific functions and which are morphologically inconspicuous or (2), to evaluate the colocalization and clustering patterns of different antigens which allow then to confirm existing connections\links (e.g. between proteins and functions) or to discover the new ones. The methods were described in 2 principle publications [1, 2].
Both the plug-ins and the program can be downloaded from this site free of charge (see "Download and Installation").
Please send all suggestions or questions to firstname.lastname@example.org.