. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 164 C. YIN AND T. HUMPHREYS groupings of cells as shown after 6 or 12 hours in Figure 4D and E. In Figure 4E the edges of the aggregates near the boundary of allogeneic contact have become rough. Over the next 6 to 8 hours the aggregates will break down into smaller clumps of cells that proceed to disintegrate completely. The failure of the cells within the two adher- ent aggregates to round up into one spherical aggregate suggests that cell movement has been suppressed by the histoincompatibility reactions. We also discover
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 164 C. YIN AND T. HUMPHREYS groupings of cells as shown after 6 or 12 hours in Figure 4D and E. In Figure 4E the edges of the aggregates near the boundary of allogeneic contact have become rough. Over the next 6 to 8 hours the aggregates will break down into smaller clumps of cells that proceed to disintegrate completely. The failure of the cells within the two adher- ent aggregates to round up into one spherical aggregate suggests that cell movement has been suppressed by the histoincompatibility reactions. We also discovered that mature aggregates harvested 48 hours after initiation of reaggregation react more quickly than newly formed aggregates. Aggregates col- lected 4 to 6 hours after the start of aggregation exhibit cytotoxic processes only after 36 hours of contact. Aggre- gates 24 hours old react more quickly (Fig. 4) and 48- hour aggregates initiate cytotoxic processes within 8 hours of apposition. Thus, the processes responsible for the cell-killing reactions mature and proceed more rapidly in the older aggregates. Gray cells Because gray cells are intimately involved in the his- toincompatibility reactions of M pmlij'cra (Humphreys, 1994), we examined the gray cells of C diffusa. Previous histological studies on C. diffusa (Smith and Hildemann, 1986a, b) failed to identify gray cells. However, an exam- ination of CMF-SW-dissociated, living C. diffusa cells under Kohler or differential interference contrast (DIG) optics revealed a small but distinct population of large, multigranular cells resembling gray cells. These cells. concentrated by purification on a density gradient, are shown in Figure 6 A and B as photographed at high power with DIC optics. The characteristic feature of gray cells is the cytoplasm filled with densely packed, highly refractive, oblate granules. The gray cells do not contain the purple pigment evident in Figure 6A and B in the variety of cell types contaminatin
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
