Ultrastructural localization of EDMTFH by immunogold labeling.

<p>Downfeathers and scales of chicken embroys at days 16 (16d) and 18 (18d) of development were labeled for EDMTFH either without (<b>A-C, G</b>) and with (<b>D-F</b>) silver enhancement. (<b>A</b>) Diffuse labeling over corneous bundles (arrow) of barbule cells (bl). (<b>B</b>) Diffuse labeling in the corneous bundles (arrow) of a subperiderm cell in a scale. (<b>C</b>) Immuno-negative control section of a barbule. (<b>D</b>) Labeling cytoplasmic corneous bundles (arrowheads) but not the cytoplasm (cy) in a barbule cell (bl). (<b>E</b>) Close-up to show the association of the labeling with corneous bundles (arrows). (<b>F</b>) Early differentiating barbule cell with short corneous bundles (arrows). (<b>G</b>) Double-labeling for EDMTFH (5 nm gold particles) and feather beta-keratin (20 nm gold particles) in a barbule cell. Note that the large particles appear to be more abundant than the small particles. A lower magnification image of the double-labeling is shown in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0167789#pone.0167789.s003" target="_blank">S3 Fig</a>. Bars: 100 nm (<b>A</b>, <b>B</b>); 200 nm (<b>C-F</b>); 50 nm (<b>G</b>).