Figure 3. Immunolocalization of Es-Caspase 3 during spermatogenesis in E. sinensis. Red: Es-Caspase 3, Green: Tubulin, Blue: Nucleus. N: nucleus, PG: proacrosomal granule, PV: proacrosomal vesicle, AT: acrosome tube, AC: acrosome cap, AV: acrosome vesicle, FL: fibrous layer, ML: middle layer, LS: lamellar structure, MC: membrane complex, RA: radical arm, NC: nuclear cap, MT: mitochondria. (A1-A4) spermatogonia, (B1-B4) spermatocyte, (C1-C4) stage I spermatid, (D1-D4) stage II spermatid, (E1-E4) stage III spermatid, (F1-F4) mature sperm. Es-Caspase 3 are expressed in the cytoplasm from spermatogonia stage to stage II spermatids. With meiosis progressing, the level gradually decreases. In stage III spermatids, Es-Caspase 3 are concentrated in the cytoplasm between nuclei and cell membrane. No signals are discovered in mature sperm. Bars=20 um.