Learning about truth and biases through experience: section surface corrugation, protein denaturation, and staining

By developing and investigating the use of thin resin sections for electron microscopy, we discovered that many of the current biases became invalid: 1) No evidence could be produced that the involved organic liquids produce the protein denaturation responsible for loss of antigenicity and lowered resolution. For immunolabeling, "water-soluble" resins are not per se to be preferred over less polar and more hydrophobic ones. 2) The relief formed by the corrugated section surface enables access to the antigenic sites. The depth of relief is determined by the strength of copolymerization and depends on temperature, the chemical nature of resin and biological matter, and, thus, also on surface modification through fixatives. The stronger the relief, the better the immunolabeling and the less the image resolution. Strong copolymerization favors flatter relief, but also a hiding of antigenic sites by thin layers of resin. 3) Heavy metal stain remains the main culprit for low resolution of sections when compared to results obtained with other preparation methods.