Phagocytosis is a fundamental cellular event for the uptake of nutrients from the environment in several kinds of eukaryote. Most ciliates egest waste and undigested materials in food vacuoles (FVs) through a cytoproct, which is a specific organelle for defecation. It is considered that FV egestion is initiated by fusion between the FV membrane and plasma membrane in a cytoproct and completed with retrieval of the membrane into a cytoplasmic space. In addition, electron microscopy indicated that microfilaments might be involved in the recycling process of the FV membrane in ciliates over 30 years ago; however, there is no conclusive evidence. Here we demonstrated actin organization on FV near a cytoproct in Tetrahymena thermophila by using a marker for a cytoproct. Moreover, it was revealed that cells treated with actin cytoskeletal inhibitor, Latrunculin B, might be suppressed for membrane retrieval in a cytoproct following FV egestion. On the other hand, the actin structures, likely to be the site of membrane retrieval, were frequently observed in the cells treated with cytoplasmic microtubules inhibitor, Nocodazole. We concluded that actin filaments were probably required for recycling of the FV membrane in a cytoproct although the role was not essential for FV egestion. In addition, it was possible that microtubules might be involved in transportation of recycling vesicles of FV coated with F-actin.

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Endometrial carcinoma coexisting with pregnancy is rarely observed. We report here the case of a 35-year-old woman with an endometrial carcinoma that was diagnosed 6 months after childbirth. Preoperative magnetic resonance imaging (MRI) revealed a cystic mass attached to the uterus, with a papillary projection on the wall of the mass. The patient underwent complete surgical extirpation and five postoperative courses of adjuvant chemotherapy, given that the tumor contents had leaked into the peritoneal cavity when the capsule of the tumor ruptured intraoperatively. Microscopic examination revealed an endometrioid adenocarcinoma in the muscular layer close to the uterine serosa that was presumed to derive from adenomyosis. Further investigation is required to elucidate the pathogenesis of endometrial carcinoma in association with pregnancy and adenomyosis.