Fig. 2. Tubular networks and secretion granules in 0.20 µm thick sections of wild-type S. cerevisiae cells. (a) A wide-meshed tubular network (arrows) is connected to an ER ribbon seen in side view (ER). Nodular dilations of variable staining are shown at arrowheads. Magnification x70,000. (b) A wide-meshed lightly stained tubular network (arrow) is seen just below the cell wall. Heavily stained dilations (arrowheads) are present at the intersections of tubules making up a Golgi network with narrower polygonal meshes (G). CW, cell wall. Magnification x66,800. (c) A tubular network (arrow) with dilations (arrowhead) is observed next to the subplasmalemmal ER (ER). The nucleus (N) is delimited by the lightly stained nuclear envelope. Magnification x72,600. (d) A wide-meshed tubular network (arrow) with an intensely stained dilation (arrowhead) is adjacent to the nucleus (N). ER, ER ribbon; SG, free secretion granules. Magnification x32,200. (e) Next to a tubular network (vertical arrow) seen side view there are secretion granules bridged by thin faintly stained tubules (arrowheads). A portion of the strongly reactive cell wall is seen at the bottom-right. V, small vacuole-like structure. Magnification x36,300. (f) Numerous secretion granules (SG) are clustered in the bud of a growing cell. Several granules are still connected (arrowhead). The cell wall is strongly stained (CW). Magnification x81,100.