Fig. 5. (A) Transmission electron micrographs of a desmosome from guinea-pig heart after infiltration with lanthanum chloride cut in transverse section. Note how the mid line has a zigzag appearance. This arises because the dense particles (P) in one row are staggered with respect to those in the opposite row, and the pale central lamella (L) has side arms that extend between the particles. (B) En face view of lanthanum-infiltrated desmosome from guinea-pig heart showing a series of alternating dark and light parallel lines of 75 Å periodicity quadratic array of lanthanum-filled spaces. D, desmosome; J, gap junction. Images in A and B are reproduced from Rayns et al. (1969) by copyright permission of the Rockefeller University Press. (C) Extracted central region from image B after high-pass filtering and masking. (D) Autocorrelation image of C to show period structure. This shows both a strong lattice repeat of 75 Å and a second weaker lattice repeat of 72 Å with a direction about 85° to the first. (E) Power spectrum of image C with intensity peaks from the lattice structure circled. (F) Fourier-filtered image using a lattice mask based on the first order peaks shown in E. Bars, 0.1 µm (A,B); 200 Å (C,D,F); reciprocal space scale bar in E, 1/100 Å^–1.