. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 342 W. D. COHEN • - *'• * • r% : • '.A • . - -itS ' •• i'-:. |* . 1 FIGURE 4. Skate erythrocyte cytoskeleton whole mount, uranyl acetate staining, TEM. (a) Survey view; the MB in this region has spread against the substratum; centrioles = ce. The "membrane skeleton," or "cell surface-associated cytoskeleton" (SAC), has collapsed onto the substratum and is visible as a back- ground network, (b) Higher magnification view of centrioles in (a), revealing that the centriole pair is attached to one, or at m
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 342 W. D. COHEN • - *'• * • r% : • '.A • . - -itS ' •• i'-:. |* . 1 FIGURE 4. Skate erythrocyte cytoskeleton whole mount, uranyl acetate staining, TEM. (a) Survey view; the MB in this region has spread against the substratum; centrioles = ce. The "membrane skeleton," or "cell surface-associated cytoskeleton" (SAC), has collapsed onto the substratum and is visible as a back- ground network, (b) Higher magnification view of centrioles in (a), revealing that the centriole pair is attached to one, or at most a few, MB microtubules. (c) Underexposed print of centrioles in b, in which centriolar substructure can be detected. tion. Thin sections confirmed that they were typical centrioles, about X with "9 + 0" substructure (Fig. 6). While most cytoskeletons contained centrioles adjacent to or near the MB, in some the centrioles were located between MB and nucleus, while in others they were adjacent to the nucleus. Figure 7 illustrates a case in which the centriole pair was closer to nucleus than to MB. In such cases, radiating microtubules usually were not evident. In all of the whole mounts examined by TEM, the cell "membrane skeleton" or "surface-associated cytoskeleton" (SAC) was visible as a background network throughout the region between nucleus and MB (Figs. 4, 5, 7). wo cytoskeletons out of several thousand examined in phase contrast were poin ; md incomplete at one end, with a curved MB at the other end. In these, the centrio were located within the pointed tip, in a region from which fibers radiated toward ihe closed end of the MB (Fig. 8). Though rare, these cytoskeletons gave the impression that the centrioles were active at one "pole" as organizing centers for a forming MB, Upon casual inspection, the spatial distribution of centrioles appeared to be non- random, with most centriole pairs close to or touch
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
