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Apical cytoplasm

About: Apical cytoplasm is a research topic. Over the lifetime, 1080 publications have been published within this topic receiving 36131 citations.


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Journal ArticleDOI
TL;DR: A stage-by-stage immunohistochemical evaluation of Sertoli cell microtubules in paraffin sections of whole rat testes using an antibody to tyrosinated alpha-tubulin is provided to provide improved methods for the evaluation of microtubular responses to environmental toxicants and testicular diseases.
Abstract: Microtubules are involved in many structural and functional changes that occur in Sertoli cells during the cycle of the seminiferous epithelium. However, few studies have addressed stage-specific changes in the distribution of microtubules that accompany the process of spermatogenesis. This study provides a stage-by-stage immunohistochemical evaluation of Sertoli cell microtubules in paraffin sections of whole rat testes using an antibody to tyrosinated α-tubulin. Microtubules that contain tyrosinated tubulin are considered to be less stable and are therefore expected to populate Sertoli cells undergoing dynamic changes during spermatogenesis. A quatitative method was developed to analyze the relative tyrosinated α-tubulin staining in different stages of the cycle. Immunostaining patterns of the stages were separated into five different groups. Stages VII–VIII had the least amount of tyrosinated α-tubulin, while stages IX–XI contained the greatest amount. The staining patterns were consistent with established structural changes in the seminiferous epithelium, such as the formation of ectoplasmic specializations, the presence of microtubule nucleation sites along the periphery of the apical cytoplasm, and the translocation of elongate spermatids from deep crypts in the Sertoli cell to the tubule lumen. These data should provide improved methods for the evaluation of microtubules in the study of Sertoli cell responses to environmental toxicants and testicular diseases.

19 citations

Journal ArticleDOI
TL;DR: A highly ordered and regionally varying F-actin network in the apical cytoplasm of the ependyma in the ventricular system of rats using fluorescein isothiocyanate-conjugated phalloidin suggests that the diverse local demands of theEpendymocytes for cellular integrity and adhesive activity against external forces are reflected.

19 citations

Journal ArticleDOI
TL;DR: Observations indicate that the AT located in the apical cytoplasm probably originate by budding off from the large endocytic vacuoles, rather than being involved in the process of endocytosis.
Abstract: The ileal absorptive cells of suckling rats exhibit high levels of endocytic activity being engaged in nonselective uptake of macromolecules from the intestinal lumen. The apical cytoplasm usually contains an extensive network of small, membrane-limited tubules (apical tubules: AT), in addition to newly formed endocytic vesicles and large endocytic vacuoles. To determine whether the AT are directly involved in the endocytic process by carrying the tracer into the cell, we have analysed movements of the apical cell membrane of the ileal absorptive cells by using a membrane-bound tracer (horseradish peroxidase-labelled cancanavalin-A: Con-A HRP). The ileal absorptive cells were exposed in vitro to Con-A HRP for 10 min at 4° C, incubated for different times in Con-A free medium at 37° C, and prepared for electron microscopy. After 1 min incubation at 37° C, invaginations of the apical cell membrane, including coated pits, and endocytic vesicles were labelled with HRP-reaction product, whereas the AT and large endocytic vacuoles were negative. After 2.5 min, almost all the large endocytic vacuoles were labelled with reaction product, which was seen in their vacuolar lumen and along the luminal surface of their limiting membrane. A few AT with reaction product were seen in the apical cytoplasm; they were in frequent connection with the reaction-positive large endocytic vacuoles. With increasing incubation time, the number of the labelled AT increased. Thus, after 15 min at 37° C, the apical cytoplasm was fully occupied by the reaction-positive AT. The ends of these AT were often continuous with small spherical coated vesicles. No reaction product was detected in the Golgi complex at any time after incubation. These observations indicate that the AT located in the apical cytoplasm probably originate by budding off from the large endocytic vacuoles, rather than being involved in the process of endocytosis.

19 citations

Journal ArticleDOI
TL;DR: Judging from the evidence of fine structure, it is conceivable that the pear-shaped cell is protozoan parasite, not a tissue cell, however, the taxonomic status of this peculiar parasite is uncertain.
Abstract: It is well known that so-called “pear-shaped cell” or “rodlet cell” is found to occur in the epithelium of the digestive tract of fishes. In the black rockfish, Sebastes inermis CUVIER, pear-shaped cells are frequently found among the columnar epithelial cells and goblet cells forming the lining epithelium of pyloric caeca (Figs. 1 and 2). Electron microscopy revealed that the cell is enclosed by a thick fibrous capsular wall (Fig. 3). Mitochondria are clustered in the apical cytoplasm. The nucleus is located at the basal end. A moderate amount of endoplasmic reticulum is scattered in the remainder of the cytoplasm as well as vesicles, vacuoles, and ribosomes. The rodlets lying parallel to the long axis of the cell are composed of three principal layers; dense central axis, moderately dense medullary part, and thin cortical layer (Fig. 3). Judging from the evidence of fine structure, it is conceivable that the pear-shaped cell is protozoan parasite, not a tissue cell. However, the taxonomic status of this peculiar parasite is uncertain.

19 citations

Journal ArticleDOI
TL;DR: The repertoire of differentiating potency of mammalian and avian pineal cells has been examined utilizing cell culture technique and it has been found that tyrosinase is expressed from the beginning of pineal formation and that its expression is stage‐specific and site‐specific.
Abstract: The repertoire of differentiating potency of mammalian and avian pineal cells has been examined utilizing cell culture technique. Skeletal muscle fibers are differentiated from pineal cells of the rat under the usual culture condition and from those of quail under hypertonic conditions. Myogenesis of pineal cells may be explained from the ontogeny of the pineal body. Anlagen of a pineal body are situated in bilateral cephalic neural folds, which also supply multipotent neural crest cells. In some conditions, almost all quail pineal cells are able to differentiate into pigmented epithelial cells and/or lens cells. Opsin containing cells found in culture of rat pineal cells may be in a similar category reflecting the “third eye”: the phylogenetic ancestor of the pineal body of avian and mammalian species. Neuron-like cells have also been reported and neuronal morphology has been intensified under the effect of testicular hyaluronidase. The cytodifferentiation described above is suggested to be different expressions of a single type of progenitor cells in the pineal body. In relation to multipotentiality of pineal cells, the original differentiating state of pineal cells is interesting; it has been found that tyrosinase is expressed from the beginning of pineal formation and that its expression is stage-specific (during embryonic period) and site-specific (predominance in the dorsal half of the pineal body and in the apical cytoplasm of the pineal cell). In the 8 day quail embryo used for culture studies, three differentiating states as to tyrosinase are noticed. However, the distinction may be apparent, as even the cells negative in tyrosinase in this stage are still ready to express tyrosinase in the suitable culture condition. Pineal cells are flexible and surprisingly susceptible to environmental factors and useful for the study of cell differentiation in general. © 1992 Wiley-Liss, Inc.

19 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202112
20205
20195
20188
20175
201615