How Do You Interpret Components in Cell Tomography?

[Pythagorean]

how would you learn to interpret the components of something like this? Am i seeing the whole cross-sectional area of a cell?

[PLAIN]http://learn.genetics.utah.edu/content/begin/cells/membranes/images/tomography.jpg

(insulin-producing pancreas cell: http://learn.genetics.utah.edu/content/begin/cells/membranes/ )

 

[Pythagorean]

more info on the picture

Front [...] view of a 3D model of the Golgi region in an insulin-secreting, mammalian cell. Â Three serial 400-nm-thick sections cut from a high pressure frozen, freeze-substituted and plastic-embedded HIT-T15 cell were reconstructed by dual axis EM tomography. Â The software package IMOD was used to model all visible objects within the resulting reconstructed volume (3.1 x 3.2 x 1.2 um3). Â The Golgi complex with seven cisternae (C1-C7) is at the center. Â The color coding is as follows: C1, light blue; C2, pink; C3, cherry red; C4, green; C5, dark blue; C6, gold; C7, bright red. Â The Golgi is displayed in the context of all surrounding organelles, vesicles, ribosomes, and microtubules: endoplasmic reticulum (ER), yellow; membrane-bound ribosomes, blue; free ribosomes, orange; microtubules, bright green; dense core vesicles, bright blue; clathrin-negative vesicles, white; clathrin-positive compartments and vesicles, bright red; clathrin-negative compartments and vesicles, purple; mitochondria, dark green. Bar, 500 nm.

 

[mack_10]

no apparent nuclei so I would suggest not a whole cross-section just fragment of cell.

probably colour coded based on density, nice resolution, interested to know how different the density between cell compartments is (are?) would have thought basically water surrounded by lipid membrane?

 

[Ygggdrasil]

The color code is not based on density, it's manually false colored based on what the researchers think each component is. As you said, there is not really much difference in the density of the components because you just have water, lipids, and some density from large protein complexes.

Also, the tomography image was created from three 400-nm sections giving a total thickness of 0.9 microns. I'm not sure about the dimensions of a pancreatic cell or how it's aligned in the image, but mammalian cell dimensions are typically on the 10-20 micron scale. So, it's likely a cross-section of about 1/10th the thickness of the cell.