The digital EM images, first captured by using a Hamamatsu CCD camera and software produced by AMT, were adjusted with Adobe Photoshop (version 7.0; Adobe Systems, San Jose, CA). Light microscopic images were captured by using the Scientific Image Processing software (version 3.070, Scanalytics, Fairfax, VA). Contrast adjustments were performed for the purpose of matching the contrast and brightness of one digital image to another within a single figure. Adobe Photoshop was also used for cropping the image and for adding text and arrows. No dodging or copy-pasting of digital images was performed.