Immunoreactivity in Sertoli cell cytoplasm adjacent to spermatid heads was dramatically evident in epithelial fragments (Figs. 3 and 4). The cytoplasm associated with junction plaque regions was strongly immunoreactive when clusters of spermatids were observed (Fig. 3, A-C) and was also evident in Sertoli cell regions surrounding single spermatids. Although this fluorescence was diffuse in many cases (Fig. 3, D and E), the pattern was more linear in others (Fig. 3, F-H). This linear pattern of dynein immunoreac-tivity is particularly striking in Sertoli cell regions associated with the spermatid head shown in Figure 4, A and B, where the linear tracts of fluorescence are oriented parallel to the long axis of the adjacent head. Interestingly, the probe was also very reactive with Sertoli cell regions surrounding tubulobulbar processes (asterisk in Fig. 3H). Cheap Diskus Advair
Distribution of IC74 Immunoreactivity in Sertoli Cells Changed during Spermatogenesis
The overall pattern of cytoplasmic dynein distribution in Sertoli cells was different in sections of seminiferous tubules at different stages of spermatogenesis. At stages when spermatids were in the early phases of elongation (stage IX, Fig. 5A), the fluorescence signal emitted by Sertoli cells was weak and appeared diffuse. This pattern was in contrast to the signal emitted from germ cells themselves, in which an intense fluorescence was emitted by the manchette. At later stages (stage XII, Fig. 5B), linear tracts of fluorescence became apparent in the cytoplasm of Sertoli cells and were generally oriented parallel to the long axis of the cells.
FIG. 3. Paired phase (A, D, and F) and immunofluorescence (C, E, and H) images of spermatids that were mechanically fragmented from the seminiferous epithelium and then fixed and labeled for cytoplasmic dynein. Two of the three fragments were also labeled for filamentous actin to indicate the position of Sertoli cell junction plaques (B and G). Sertoli cell cytoplasm surrounding elongate spermatid heads was highly immu-noreactive with the antibody to cytoplasmic dynein (large white arrowheads in C and D). Immunoreactivity in Sertoli cell regions associated with the spermatid indicated by the arrow in A occurred as a linear signal that outlined the spermatid head (small white arrowheads in C). Also visible is a positive signal (top white arrow in C) emitted from within the head itself. Immunoreactivity with the dynein probe occurred in two regions of the Sertoli cell associated with late spermatids. A bright, but diffuse, signal (asterisk in H) occurred in regions associated with the concave or ventral surface of the spermatid head. A weak, but detectable, signal also occurred in regions associated with the Sertoli cell junction plaque (white arrowheads in H) as indicated by the actin staining in G. No detectable signal was emitted from within late spermatids themselves.
FIG. 4. Paired fluorescence (A) and phase (B) micrographs of a spermatid and related Sertoli cell cytoplasm mechanically dissociated from fixed seminiferous epithelium and incubated with a probe for cytoplasmic dy-nein (intermediate chain). Specific staining with the dynein probe occurred in linear tracts (arrows) presumably associated with the junction plaque and oriented parallel to the long axis of the spermatid head.
FIG. 5. Stage-specific staining of the seminiferous epithelium with an immunological probe for cytoplasmic dynein (intermediate chain). Immunoreactivity with the probe occurred both in spermatogenic cells and in Sertoli cells. In spermatogenic cells, staining occurred mainly in association with the manchette. In stages of spermatogenesis containing early elongate spermatids, such as in stage IX shown in A, manchette staining was prominent, whereas immunoreactivity in Sertoli cells was relatively weak. As spermatids became more elongate (B), manchette staining became less apparent and immunoreactivity increased in Sertoli cells, particularly in regions associated with spermatid heads. At stage V (C), when spermatids were deep within Sertoli cell crypts, staining in Sertoli cells was dramatically evident. This staining was in the form of linear tracts oriented parallel to the long axis of the adjacent spermatids. Just before sperm release, intense immunoreactivity occurred in Sertoli cells, both in columnar portions of the cells and in apical cytoplasm surrounding the spermatid heads.