Changes In Cytoplasmic Morphology Research Articles

Balbiani body formation and cytoplasmic zonation during early oocyte development in two Clupeiform fishes.

The Balbiani body (Bb) was examined in primary growth phase oocytes for the first time in two clupeoid fish species, the Mediterranean sardine, Sardina pilchardus, and the European anchovy, Engraulis encrasicolus, which belong to different families, Clupeidae and Engraulidae, respectively. Cytoplasmic morphological changes of early secondary growth oocytes were also investigated using confocal laser scanning microscopy, light and transmission electron microscopy. The ultrastructural observations showed that the two species develop a distinct spherical Bb. However, differences in the cytoplasm, mainly in the perinuclear area, were observed. Briefly, in sardine the Bb coexists with a thick perinuclear ring containing mitochondria, nuage, endoplasmic reticulum and small vesicles, while in anchovy this perinuclear ring is thinner, consisting of complexes of nuage and mitochondria. After the disassembly of the Bb, a prominent cytoplasmic zonation develops in the secondary growth oocytes of sardine and anchovy, although with different organelle distribution between the two species. Sardine oocytes exhibit a thick zone of endoplasmic reticulum around the nucleus, whereas in those of anchovy, a thick mitochondria-rich ring surrounding the nucleus was observed. The cytoplasmic characteristics, such as the perinuclear ring in primary oocytes in sardine and the mitochondria-rich ring of early secondary oocytes in anchovy, are also discernible in histological sections by standard procedures and could thus be used as indicators of maturity or imminent spawning period in routine light microscopy observations, providing a valuable tool for applied fisheries biology.

The anticancer potential of lemongrass and cinnamon extracts on human hepatocellular carcinoma cell line (HepG2): the possible effectiveness of combined treatment

Background and Objectives: Hepatocellular carcinoma is considered the third most frequent cause of cancer-related death. This study was aimed to discover efficacious and cheap alternative natural medicines with less or no adverse effects of chemotherapy. The possible anticancer potential and underlying mechanisms of combined Cinnamomum zeylanicum (Cinnamon) and Cymbopogon citratus (lemongrass) aqueous extracts on human hepatocellular carcinoma cells (HepG2) was investigated. Methodology: Antioxidant potential, flavonoids and total phenolic content (TPC) of both extracts were evaluated. Cytotoxic activity of combined extracts was assessed using neutral red uptake method. Morphological changes were evaluated using Giemsa and Acridine orange/ ethidium bromide (AO/EBr) fluorescent staining characterized with the apoptotic nuclear and cytoplasmic morphological changes significantly (P≤0.05) recorded at both doses of combined treatment. Cell proliferation and cell apoptosis capability were assessed using Ki-67 and Bcl-2 immunocytochemical reaction respectively. Results: Cytoplasmic morphological changes were characterized by apoptotic and cytotoxic features (P≤0.05) at both doses of combined treatment. Anti-proliferation and cell apoptosis capaility of combined treatment on HepG2 cells proved with a decrease in mitotic index, Ki-67 expression and Bcl-2 down regulation. Additionally, DNA fragmentation on agaraose gel showed a cytotoxic effect and micronucleus evidence (P≤0.05) was increased with dose dependent manner. Autophagy was evaluated as a result of extracts treatment with a significant (P≤0.05) increase of autophagic vesicles in treated HepG2 cells was observed among the treated groups. Conclusion: Combined treatment of cinnamon and lemongrass extracts can exert anti-cancer effects as apoptosis induction, autophagic cell death activation and inhibiting cell proliferation on HepG2 cells.

The stress-inducible transcription factor ATF4 accumulates at specific rRNA-processing nucleolar regions after proteasome inhibition

Functional protein homeostasis is essential for the maintenance of normal cellular physiology, cell growth, and cell survival. Proteasome inhibition in cancer cells can disturb protein homeostasis in such a way that synthetic proteasome inhibitors like bortezomib may selectively kill myeloma cells. Solid cancer cells appear to respond less to bortezomib which may in part be due to a rescue mechanism of the unfolded protein response/endoplasmic reticulum stress mechanism which leads to a temporary shutdown of protein biosynthesis at the translational level. Here we show that proteasome inhibition by bortezomib may also interfere with general protein biosynthesis already at the stage of nucleolar ribosome biogenesis. Ultrastructural analysis revealed not only that bortezomib induces conspicuous changes in cytoplasmic morphology but also pronounced morphological changes of the nucleolar ultrastructure, associated with an accumulation of the transcription factor ATF4 at nucleolar sites. Stress-induced intra-nucleolar ATF4 accumulation was observed in cancer cells in a dose and time dependent manner and ultrastructural studies revealed that ATF4 is preferentially localized inside the dense fibrillar and granular component of nucleoli. Furthermore, bortezomib affected not only the number of nucleoli, but also the volume and distribution of nucleolar components. The localization of ATF4 in the granular component of nucleoli together with its association with nascent RNA transcripts in cells undergoing proteotoxic cell stress could suggest a new function for ATF4 in cell stress management.

Effective Cellular Morphology Analysis for Differentiation Processes by a Fluorescent 1,3a,6a-Triazapentalene Derivative Probe in Live Cells.

Nuclear and cytoplasmic morphological changes provide important information about cell differentiation processes, cell functions, and signal responses. There is a strong desire to develop a rapid and simple method for visualizing cytoplasmic and nuclear morphology. Here, we developed a novel and rapid method for probing cellular morphological changes of live cell differentiation process by a fluorescent probe, TAP-4PH, a 1,3a,6a-triazapentalene derivative. TAP-4PH showed high fluorescence in cytoplasmic area, and visualized cytoplasmic and nuclear morphological changes of live cells during differentiation. We demonstrated that TAP-4PH visualized dendritic axon and spine formation in neuronal differentiation, and nuclear structural changes during neutrophilic differentiation. We also showed that the utility of TAP-4PH for visualization of cytoplasmic and nuclear morphologies of various type of live cells. Our visualizing method has no toxicity and no influence on the cellular differentiation and function. The cell morphology can be rapidly observed after addition of TAP-4PH and can continue to be observed in the presence of TAP-4PH in cell culture medium. Moreover, TAP-4PH can be easily removed after observation by washing for subsequent biological assay. Taken together, these results demonstrate that our visualization method is a powerful tool to probe differentiation processes before subsequent biological assay in live cells.

Morphological and quantitative features of mitral cells in the rat olfactory bulb after administration of propranolol.

To determine the cytoplasmic morphological changes in the mitral cells and quantitative changes (number of mitral cells and thickness of mitral cell layer in microns) in the rat olfactory bulb after administration of propranolol. Experimental study. The Department of Anatomy, University of Health Sciences, Lahore, from January 2006 to January 2007. Twenty samples were obtained from two randomly divided groups of rats, each comprising 10 animals for control and experimental work respectively. Each group was treated with normal saline (5 ml/kg) and propranolol (1 mg/kg) respectively for one month. The skull was fixed in 20% formalin for 10 days and decalcified in 10% formalin/10% nitric acid. The olfactory bulb along with olfactory cortex was dissected. After processing, 10 microns thick sections were obtained. The slides were stained with Hematoxylin and Eosin and Bielschowksy's silver stain (Glees-Marsland modification) and studied under light microscope. The morphology, quantitative analysis of mitral cell layer and the number of mitral cells were studied in the histological study and compared using t-test with significance at p < 0.05. In the propranolol treated group changes observed in the morphology of the mitral cells included presence of cytoplasmic vacuoles at the periphery of the cells. There was significant increase in the thickness of mitral cell layer and number of the mitral cell in the propranolol treated group (p < 0.05). This study showed morphological and quantitative changes in the olfactory bulb in response to treatment with propranolol, hence it has implications in odour induced learning.

Desmocollin 1 expression and desmosomal remodeling during terminal differentiation of human anagen hair follicle: an electron microscopic study.

The terminal differentiation (TD) program of keratinocytes of the human hair follicle (HF) occurs with specific temporal and spatial features in the various layers of the inner root sheath (IRS) and in the innermost layer of the outer root sheath (companion layer). This process is characterized by complex nuclear and cytoplasmic morphological changes, accompanied by profound modifications in intercellular junctions. As no correlation exists between the structure and the molecular composition of desmosomes during TD of the IRS/companion unit, the aim of our study was to investigate by transmission electron microscopy the remodeling of desmosomes in keratinizing cells of these compartments. By immunogold post embedding technique, we studied in anagen HFs the modulation of the synthesis of desmocollin 1 (Dsc1), a transmembrane glycoprotein specifically synthesized in the IRS and in the companion layer. Dsc1 immunoreactivity was actually confined to these compartments and tended to increase just before the level of TD, particularly in the Henle's layer and in the IRS cuticle. In Huxley's layer, the immunolabeling was patchy and in the companion layer Dsc1 synthesis was detected above the level of keratinization of Huxley's layer. In the whole IRS, concomitantly with TD, there was an abrupt and almost complete disappearance of Dsc1 synthesis. An asymmetric distribution of Dsc1 was noticed (i) between cells at different stages of differentiation and (ii) between cells belonging to layers with different spatial/temporal features of TD. Our results show that the ultrastructural modifications of desmosomes during TD of HF are paralleled by the modulation of the synthesis of desmocollin 1.

Ultrastructural studies on the interaction of β-amyloid peptide and mouse neuroblastoma cells NB41A3

10.1002/(SICI)1520-6769(199601)18:1<39::AID-NRC138>3.3.CO;2-ZNB41A3 cells were used to investigate the effects of binding of a synthetic β-amyloid peptide, β1–40, to cellular membranes. Using a relatively low concentration of β1–40 we observed small changes in cytoplasmic morphology and nuclear damage. We also noted increases in vacuoles, the presence of particles within the nucleus and in the expanded perinuclear cisternal space after a three-day treatment with β1–40. Using immunocyto-chemistry we directly show β1–40 bound to and inside the NB41A3 cell. This result provides further evidence suggesting AβP-induced cell death in vitro is via an apoptotic mechanism.

Ultrastructural changes of female Syrian hamster cystic duct epithelium as a result of sex steroid treatment

In view of the lack of sufficient data regarding the morphology of the cystic duct and the extensive focus on the gallbladder, a preliminary examination of the cystic duct response to female sex steroid treatment was conducted to follow up a detailed ultrastructural study of the gallbladder epithelial response to a similar treatment. As observed in the gallbladder epithelium, the cystic duct epithelial cells of nulliparous Syrian hamsters demonstrate morphologic changes in response to female sex steroid treatment. Control (C) cystic duct epithelial cells are covered by short microvilli and each cell appears to exhibit a single vestigial cilium. Estrogen (E)- and estrogen + medroxyprogesterone (E + MP)- treatments induce differential duct cell morphologic changes. These changes are the result of steroid treatments in the significant decreasing sequence E > E + MP > C for nuclear volume, indentations and perinuclear lysosomal/lipofuscin bodies. Moreover E + MP-treatment results in larger cytoplasmic volume and more sloughing of apical cell excrescences than following E treatment. It is suggested that, similar to that in the gallbladder, the action of progestin is paramount in favoring cytoplasmic morphological changes in the cystic duct which, along with the alteration of mucus, cell sloughing, decreased bile acids and motility could also participate in the gallstone nucleation process as they are brought into the gallbladder with the incoming bile flow.

Ultrastructural analysis of β-amyloid-induced apoptosis in cultured hippocampal neurons

Following treatment with the β-amyloid (Aβ) 25–35 analog, scanning and transmission electron microscopy were used to investigate the morphological changes in cultured hippocampal neurons during the course of degeneration. Ultrastructural analysis revealed focal cell surface blebbing and rapid condensation of nuclear chromatin. Changes in cytoplasmic morphology included prominent vacuole formation, dispersal of polyribosome rosettes and the disappearance of the golgi complex, smooth endoplasmic reticulum and microtubules with increased cytoplasmic electron density. Mitochondria and limited rough endoplasmic reticulum remained intact throughout the process of cell death. These results provide additional evidence suggesting Aβ-induced cell death in vitro occurs via an apoptotic mechanism.