Intestine anatomy.

<p>(A) Schematic diagram of selected intestinal rings (int rings) and the terminal valve ring in a newly hatched larva. R (right) and L (left) designate the positions of the labeled cells at the E16 stage. The int rings are color coded with different hues; R and L cells within each int ring are colored with different saturations of the same hue. The arrows shown for the body axes indicate the direction of view for all optical stacks. For example, views of optical sections through either the left or right side of the primordium will be displayed with anterior to the left and dorsal top. (B) Diagram of transverse sections through a single embryo at about 515 minutes, showing cell and tissue boundaries. The drawings are tracings from serial-section electron micrographs available at <a href="http://www.wormimage.org/imageList.php?wormName=embryo_RDD" target="_blank">http://www.wormimage.org/imageList.php?wormName=embryo_RDD</a>. Each of the four muscle quadrants consists of a longitudinal row of proximal muscles (with respect to the midline) and a single row of distal muscles. The quadrants also include several muscle processes that are not included in the diagram. (C and D) Images of live, newly hatched larvae expressing transgenic reporters for intestinal cells (green) and for all membranes (red). Panel C is an optical plane through the center of the intestine, showing the closed lumen, and panel D is an optical plane near the surface of the intestine. The inset in panel C shows a single int ring; the membranes around the lumen appear thicker than the lateral membranes because of the numerous microvilli in the brush border. (E and F) Images from 3D reconstructions of the E16 primordium (panel E; <a href="http://www.plosgenetics.org/article/info:doi/10.1371/journal.pgen.1005950#pgen.1005950.s005" target="_blank">S1 Video</a>) and of the intestine in a newly hatched larva (panel F; <a href="http://www.plosgenetics.org/article/info:doi/10.1371/journal.pgen.1005950#pgen.1005950.s006" target="_blank">S2 Video</a>). The right side of the primordium in panel E is shown as a mirror-right image for comparison with the left side view, and to match the orientation of optical sections presented throughout the paper. (G) High magnification view of the int3 and int4 rings from the reconstruction as in panel F. The 4R cell is removed to show internal cell surfaces, the intestine lumen, and adherens junctions flanking the lumen. Note that the reconstructed apical surface is flattened or closed; see also <a href="http://www.plosgenetics.org/article/info:doi/10.1371/journal.pgen.1005950#pgen.1005950.s004" target="_blank">S4A Fig</a>. (H) Diagram of the intestinal lumen after it opens. (I) Diagram of the basal surfaces of intestinal cells showing possible diagonal contacts between the lateral faces of four cells in adjacent int rings; RaL = Right to anterior Left, LaR = Left to anterior Right. (J) Diagram of the basal surface of a tube of hexagonally packed intestinal cells, cut along the ventral midline and unrolled. Phantom cells (dashed lines) are included to show the complete pattern of diagonal contacts. Panels C and D show strain JJ2360. Bars = 5 microns.