Showing papers on "Apical cytoplasm published in 2009"

Notes on midgut ultrastructure of Cimex hemipterus (Hemiptera: Cimicidae).

Abstract: This work studied the ultrastructure of the midgut cells of Cimex hemipterus Fabricius (Hemiptera: Cimicidae). The midgut of adult insects was analyzed on different days after a bloodmeal, and three anatomical regions with different digestive functions were apparent. In the anterior midgut, the digestive cells had many spherocrystals, lipid inclusions, and glycogen deposits, suggesting a role in water absorption, ion regulation, digestion, and storage of lipids and sugars. The digestive cells in the middle midgut contained secretory granules in the apical cytoplasm, lysosomes, and large amounts of rough endoplasmic reticulum, suggesting that this midgut region was active in digestive processes. The posterior midgut contained digestive cells with secretory vesicles, lysosomes, rough endoplasmic reticulum, and spherocrystals, suggesting digestion and ion/water absorption. Also, there was strong evidence that the posterior midgut may be the major site of nutrient absorption. The hematophagous heteropteran groups share many of these blood digestion mechanisms.

The central nervous system of sea cucumbers (Echinodermata: Holothuroidea) shows positive immunostaining for a chordate glial secretion

Abstract: Echinoderms and chordates belong to the same monophyletic taxon, the Deuterostomia. In spite of significant differences in body plan organization, the two phyla may share more common traits than was thought previously. Of particular interest are the common features in the organization of the central nervous system. The present study employs two polyclonal antisera raised against bovine Reissner's substance (RS), a secretory product produced by glial cells of the subcomissural organ, to study RS-like immunoreactivity in the central nervous system of sea cucumbers. In the ectoneural division of the nervous system, both antisera recognize the content of secretory vacuoles in the apical cytoplasm of the radial glia-like cells of the neuroepithelium and in the flattened glial cells of the non-neural epineural roof epithelium. The secreted immunopositive material seems to form a thin layer covering the cell apices. There is no accumulation of the immunoreactive material on the apical surface of the hyponeural neuroepithelium or the hyponeural roof epithelium. Besides labelling the supporting cells and flattened glial cells of the epineural roof epithelium, both anti-RS antisera reveal a previously unknown putative glial cell type within the neural parenchyma of the holothurian nervous system. Our results show that: a) the glial cells of the holothurian tubular nervous system produce a material similar to Reissner's substance known to be synthesized by secretory glial cells in all chordates studied so far; b) the nervous system of sea cucumbers shows a previously unrealized complexity of glial organization. Our findings also provide significant clues for interpretation of the evolution of the nervous system in the Deuterostomia. It is suggested that echinoderms and chordates might have inherited the RS-producing radial glial cell type from the central nervous system of their common ancestor, i.e., the last common ancestor of all the Deuterostomia.

Starvation induces apoptosis in the midgut nidi of Periplaneta americana : a histochemical and ultrastructural study

Abstract: The effects of starvation on cell death in the midgut of Periplaneta americana were studied histochemically and ultrastructurally TUNEL assays showed that cell death began to increase in the columnar cells and nidi, the nests of stem cells and newborn cells from 2 weeks of starvation A significant increase in cell death occurred in the nidi after 4 weeks of starvation Cockroaches starved for 4 weeks showed active-caspase-3-like immuno-reactivity both in the columnar cells and nidi, whereas control cockroaches that were fed for 4 weeks showed this reactivity only in the apical cytoplasm of columnar cells Electron microscopy revealed no chromatin condensation in the nucleus of columnar cells of cockroaches, whether fed or starved for 4 weeks Starved cockroaches exhibited many small vacuoles in the cytoplasm of some columnar cells and “floating” organelles including nuclei in the lumen A 4-week starvation induced the appearance of cytoplasmic fragmentation and secondary lysosomes in the nidi Each fragment contained nuclear derivatives with condensed chromatin, ie apoptotic bodies Mitotic cells were found in some, but not all nidi, even within the same starved sample Fragmentation was not observed in the nidi of control cockroaches Thus, starvation increases cell death not only in the columnar cells, but also in the nidi The cell death in the nidi is presumably apoptosis executed by caspase 3

Structure of the Lining Epithelium of the Cauda Epididymis of the Golden Hamster

Abstract: Summary The ductus epididymis has roles in the maturation and storage of spermatozoa. The main function of the cauda epididymis is the storage of spermatozoa; however, this region exerts other morphophysiological roles. So, this study was aimed at investigating structural features of the cauda epididymis epithelium, which could indicate roles other than the storage. The relative percentages of the cell types in the epithelium were 74.9, 6.9, 12.5 and 5.6% of principal, clear, basal and halo cells respectively. Large intercellular spaces were seen among the lateral plasmatic membranes of adjacent principal cells or among these cells and others cell types. These spaces were found to be filled with multivesicular bodies, myelin figures, scrolls and debris of membranes or flocculent dense material. Clear cells had the cytoplasms filled with lysosomes (¾ of basal cytoplasm), and vacuoles and vesicles (¼ of apical cytoplasm). The observations allowed us to infer that clear cells could act in the process of endocytosis and also in water transfer from the lumen to the interstitium through the epithelium compartment. Moreover, transcytosis may occur at the cauda epididymis of Golden hamster.

Expression, Localization, and Binding Activity of the Ezrin/Radixin/Moesin Proteins in the Mouse Testis

Abstract: The ezrin, radixin, and moesin (ERM) proteins represent a family of adaptor proteins linking transmembrane proteins to the cytoskeleton. The seminiferous epithelium undergoes extensive changes in cellular composition, location, and shape, implicating roles of the membrane-cytoskeleton interaction. It remains unknown, however, whether the ERM proteins are expressed and play significant roles in the testis. In the present study, we examined the spatiotemporal expression of ERM proteins in the mouse testis by Western blotting and immunohistochemistry. Ezrin immunoreactivity was demonstrated in the cytoplasm of steps 15 and 16 spermatids from 5 weeks postpartum through adulthood, whereas radixin immunoreactivity was in the apical cytoplasm of Sertoli cells from 1 week through 2 weeks postpartum. No immunoreactivity for moesin was detected at any age. Immunoprecipitation demonstrated that ezrin was bound to the cytoskeletal component actin, whereas radixin was bound to both actin and tubulin. Of the transmembrane proteins known to interact with ERM proteins, only cystic fibrosis transmembrane conductance regulator, a chloride transporter, was bound to ezrin in elongated spermatids. These results suggest that ezrin is involved in spermiogenesis whereas radixin is involved in the maturation of Sertoli cells, through interaction with different sets of membrane proteins and cytoskeletal components.

Ultrastructural and Histochemical Observations on Serous Ovarian Cystadenomas

Abstract: One hundred and twelve serous ovarian cystadenomas (46 benign, 33 tumours of borderline malignancy and 33 malignant tumours) were investigated with histological and mucin histochemical methods. Electron microscopy was applied to 9 benign, 6 borderline and 5 malignant tumours. The epithelium of the benign serous cystadenomas contained ciliated and nonciliated columnar cells, which sometimes were edematous ("pale cells"), and smaller basal cells. The large Golgi apparatus with small secretory vesicles and occasional larger secretory granules was located in the apical cytoplasm. There were numerous pinocytotic vesicles at the basal plasma membrane. The extracellular mucin in the cystic lumen and the mucin on the apical epithelial border consisted of material with vic-glycols (1.2-hydroxyl groups) mixed with sulpho- and carboxymucin. With increasing degree of malignancy the number of ciliated cells diminished and were not found in the malignant epithelium. The number of nucleoli and the amount of carboxymucin with sialic acid residues increased with increasing degree of malignancy. However, there were no single consistent ultrastructural feature which could be considered as a reliable criterion for malignancy of these tumours in the absence of invasive growth. The findings support the view that serous ovarian cystadenomas are of coelomic origin.

The prenatal development and histochemistry of the ileal mucins in the bovine fetuses.

Abstract: Few studies exist regarding the distribution of intestinal mucins in fetuses of mammalians such as cattle and sheep. In this study, we aimed to describe the changes in the mucin production by ileal epithelium of bovine fetuses during their prenatal development. The goblet cells showed heterogeneity in mucins and the apical cytoplasm of the enterocytes demonstrated Periodic acid Schiff-positive reaction which declined gradually towards the birth. Moreover, the number of the goblet cells containing acidic and mixed mucins augmented, whereas those containing neutral mucins decreased with advancing gestational age. After sixth month of gestation, with the initiation of the ileal Peyer patches and follicle-associated epithelium development, a gradual increase in the number of goblet cells containing sulfomucins was also noticed towards the birth. The presence of different mucins in the ileum of bovine fetuses throughout prenatal development might play a role in the protection of the intestinal mucosa against urinary waste products in swallowed amniotic fluid and bile. Furthermore, mucins can also contribute for the formation of meconium in intra-uterine life and building of strong intestinal barrier with predominating sulfomucins, protecting the intestine against potential pathogens and digestive enzymes after birth.

Carcino-embryonic antigen (CEA) in gastric adenocarcinomas. Morphologic patterns and their relationship to a histogenetic classification.

Abstract: The presence of carcino-embryonic antigen (CEA) was studied in 92 consecutive cases of gastric adenocarcinoma, using the two-layer conjugated immunoperoxidase technique. Three characteristic patterns of CEA localization were identified. Type I: Intracytoplasmatic granules covering the entire cytoplasm of the malignant cells. Type II. Linear or granular deposits along the glycocalyx or in the apical cytoplasm of the malignant cells. Type III: Tumour cells negative for CEA or only showing a very weak reaction in a few cells. These CEA patterns were significantly related to the histogenetic classification of gastric adenocarcinomas proposed by Mulligan & Rember. The majority of the "mucus cell carcinomas" showed the type I CEA pattern. "Intestinal cell carcinomas" predominantly showed the type II CEA pattern and the "pyloro-cardiac gland carcinomas" the type III CEA pattern. The significance of the CEA patterns in respect of the histogenetic classification is discussed.

Immunohistochemical localization of NPY, VIP and 5-HT in the thyroid gland of the lizard, Podarcis sicula.

Abstract: The thyroid gland of the lizard Podarcis sicula was immunohistochemically studied in adult male specimens using specific antibodies against NPY, VIP and 5-HT and the avidin-biotin peroxidase complex (ABC) procedure to localize the three peptides. Fine beaded VIP-immunoreactive nerve fibers ran between the follicles, and VIP-immunoreactivity was evenly distributed in the apical cytoplasm of follicular cells. NPY-immunoreactive fibers were found around the follicles, and, in the cells, immunoreactivity was localizated only in the cellular apices. Immunoreactivity to 5-HT was observed in the colloid, with a concentration in the follicular lumen exceeding that in the follicular cells. In fact, most follicles showed immunoreactivity in the cytoplasmic bridges formed between the apical portion of the follicular cells and the colloid.

Vas Deferens Surface Epithelium of Agouti paca: Fine Structural Features Epitelio del Conducto Deferente de Agouti paca. Observaciones de Estructura Fina

Abstract: SUMMARY: The surface epithelium of the vas deferens of Agouti paca, a wild and large South American rodent, was basically formed by principal and basal cells being only the principal cells related to endocytosis processes and also secretion taking base on their cytoplasmic ultrastructural features. Principal cell of vas deferens epithelium were characterized mainly by presence of vesicles with several shapes, sizes and internalized content at their apical cytoplasm occurring smaller pits and pale small vesicles seen next to the apical brush border of microvillus. Moreover, coated vesicles, smooth surface vesicles and great vesicles; multivesicular bodies, endosomes and lysosomes were seen. Presence of an apocrine secretory apparatus was also viewed, showing apical cytoplasmic expansions protruding into the vas deferens luminal compartment. The basal flattened cells, without luminal surface contact, occurred next to the basement membrane of the ductus, and did no exhibit special ultrastructural features.

Ankara tavşanı ince bağırsağında Paneth hücrelerinin morfolojisi, histokimyası ve ince yapısı üzerinde çalışmalar

Abstract: The present study was undertaken to determine the morphology, histochemical properties, localization and quantitative distribution of Paneth cells in the small intestine of the Angora rabbit Tissue samples taken from the duodenum, jejunum and ileum of 10 healthy adult Angora rabbits, obtained from private breeders, constituted the material of the study The Paneth cells, which were determined to be located within the crypts of Lieberkuhn, were identified on their basally located nucleus and apically located acidophilic granules These granules gave positive reactions with Mallory’s triple staining technique as well as with the application of Phloxine-tartrazine, Alcian blue-performic acid and Mallory’s phosphotungstic acid-hematoxylin method Staining with periodic acid-Schiff (PAS), Alcian blue (pH 25), and PAS-Alcian blue pH 25 gave negative reactions Paneth cells were determined not to display a uniform distribution throughout the small intestine and cell numbers were ascertained to show a gradual increase from the duodenum towards the ileum The difference between the three regions of the small intestine was determined to be statistically significant (p<001) Electron microscopic examination revealed the presence of electron-dense and homogenous granules in the apical cytoplasm of some Paneth cells, whereas homogenous granules of different electron density existed in some other cells