scholarly journals Muscle scars in Porcellia (Gastropoda; Pleurotomariacea) from the Carboniferous of England

1986 ◽  
Vol 35 ◽  
pp. 53-58 ◽  
Author(s):  
John S. Peel
Keyword(s):  
Systematic Position ◽  
Apical Surface ◽  
Internal Mould ◽  
Basal Surface ◽  
Morphological Convergence

1\vo shell retractor muscles are described on an internal mould of Porcellia woodwardi, a pleurotomaria­cean gastropod from the Carboniferous of England. The scars are located at the junction between the um­bilical wall, and the apical surface and the basal surface, respectively. Similar positioning of muscle scars in Bellerophon of the same age reflects morphological convergence of the planispiral, anisostrophic Por-cellia with the planispiral, but isostrophic Bellerophon. It is concluded that the shape of muscle scars, in detail, can not contribute to solving the question of the systematic position of Bellerophon.

Extracellular glutamate flux regulates intracellular glutaminase activity in LLC-PK1-F+ cells

1995 ◽  
Vol 268 (6) ◽  
pp. C1418-C1424 ◽  
Author(s):  
T. C. Welbourne ◽  
X. Mu
Keyword(s):  
Time Course ◽  
Glutamate Uptake ◽  
Fold Increase ◽  
Cellular Level ◽  
Glutamine Metabolism ◽  
Apical Surface ◽  
Extracellular Glutamate ◽  
Basal Surface ◽  
F Cells ◽  
Glutaminase Activity

The role of extracellular glutamate flux in regulating intracellular glutaminase activity was assessed in confluent monolayers of proximal tubule-like LLC-PK1-F+ cells grown on porous supports. Glutamate is a well-known inhibitor of phosphate-dependent glutaminase (PDG). We hypothesized that, by restricting the flux of glutamate from the extracellular media, cellular level would fall, effecting deinhibition of the cellular glutaminase activity. To test this, cellular glutamate uptake and extracellular production were inhibited for 18 h by the addition of D-aspartate (10 mM) or acivicin (0.7 mM) to both apical and basal media. Inhibiting glutamate flux depressed cellular glutamate content 43 and 41%, respectively. Intracellular relative glutaminase activity, monitored as the breakdown of 14C-radiolabeled glutamine to glutamate, measured over 60 s in the presence of D-aspartate or acivicin showed a 2- to 2.5-fold increase with the fall in cellular glutamate. Interestingly, enhanced glutamine uptake after PDG deinhibition was predominantly expressed on the basal surface. Indeed, measuring glutamine utilization after gamma-glutamyltranspeptidase inhibition over the entire 18-h time course revealed inhibition at the apical surface but relative enhancement of uptake at the basal surface. The increased intracellular glutaminase pathway was also reflected in increased alanine production measured over the 18-h time course, despite the reduction in overall glutamine utilization. These results point to a major role for extracellular glutamate fluxes in regulating cellular glutamine metabolism and suggest that the intracellular pathway may be suppressed under these conditions.

Polarized properties of thyroid cells: A study with cultured porcine cells

1987 ◽  
Vol 116 (1_Suppl) ◽  
pp. S220-S224 ◽  
Author(s):  
Jean Mauchamp ◽  
Odile Chabaud ◽  
Marianne Chambard ◽  
Corinne Gerard ◽  
Claude Penel ◽  
...  
Keyword(s):  
Cell Layer ◽  
Culture Conditions ◽  
Thyroid Cell ◽  
Apical Surface ◽  
Cell Plasma Membrane ◽  
Basal Surface ◽  
Thyroid Cells ◽  
Cell Plasma ◽  
Apical Compartment ◽  
Cell Layers

Abstract. In primary culture porcine cells form polarized cell layers. We have designed culture conditions in which we can have access to only one side of the cell layer, either the apical or the basal surface. In addition, using culture chambers with permeable bottom we can have access to either side of the cell layer which separates two compartments. Using these organized systems we have shown that the iodide concentrating mechanism and the TSH-reseptor adenyl cyclase complex are localized on the basolateral domain of the thyroid cell plasma membrane. We also demonstrated the existence on the apical surface of an amiloride sensitive sodium uptake. Finally we observed that about 10% of newly synthesized thyroglobulin appears to be secreted directly into the basal compartment, 90% being secreted in the apical compartment.

Levels of annexin IV and V in the plasma of pregnant and postpartum women

2004 ◽  
Vol 91 (06) ◽  
pp. 1129-1136 ◽  
Author(s):  
Junko Masuda ◽  
Eiji Takayama ◽  
Ayano Satoh ◽  
Michiru Ida ◽  
Tadashi Shinohara ◽  
...  
Keyword(s):  
Pregnant Women ◽  
Anticoagulant Activity ◽  
Normal Pregnancy ◽  
Postpartum Women ◽  
Apical Surface ◽  
Basal Surface ◽  
Disseminated Intravascular Coagulopathy ◽  
V Protein ◽  
Intravascular Coagulopathy ◽  
Annexin Iv

SummaryAnnexin (Anx) V is pivotal in the maintenance of pregnancy by preventing the activation of blood coagulation. The homology of the amino acid sequence between Anx IV and Anx V is highest in Anx family proteins. However, little is known about the roles of Anx IV in pregnancy.The aim of this study is to clarify the roles of circulating Anx IV and Anx V in normal pregnancy. Subjects were non-pregnant women (n = 50), 120 pregnant women, and maternal subjects just after delivery (n = 53) or postpartum (n = 67). Anx IV in the plasma of non-pregnant women was at a concentration 20 times that of Anx V. The plasma levels of Anx IV suddenly increase after delivery, but Anx V levels remain low during this period. Anx IV and Anx V exert similar levels of anticoagulant activity. Anx IV protein was expressed on the basal surface of syncytiotrophoblasts; Anx V protein, on the apical surface of syncytiotrophoblasts. These results suggest that Anx IV enters the maternal bloodstream just after delivery and might play a role in preventing disseminated intravascular coagulopathy, and that Anx V helps to prevent clotting in the placenta during pregnancy.

scholarly journals Structural centrosome aberrations sensitize polarized epithelia to basal cell extrusion

Open Biology ◽  
2018 ◽  
Vol 8 (6) ◽  
pp. 180044 ◽  
Author(s):  
Olivier Ganier ◽  
Dominik Schnerch ◽  
Erich A. Nigg
Keyword(s):  
Basal Cell ◽  
Cell Damage ◽  
Apical Surface ◽  
Basal Surface ◽  
Epithelial Monolayers ◽  
Metastatic Cells ◽  
Oncogenic Mutations ◽  
Promote Cell Survival ◽  
Polarized Epithelia ◽  
Cell Extrusion

Centrosome aberrations disrupt tissue architecture and may confer invasive properties to cancer cells. Here we show that structural centrosome aberrations, induced by overexpression of either Ninein-like protein (NLP) or CEP131/AZI1, sensitize polarized mammalian epithelia to basal cell extrusion. While unperturbed epithelia typically dispose of damaged cells through apical dissemination into luminal cavities, certain oncogenic mutations cause a switch in directionality towards basal cell extrusion, raising the potential for metastatic cell dissemination. Here we report that NLP-induced centrosome aberrations trigger the preferential extrusion of damaged cells towards the basal surface of epithelial monolayers. This switch in directionality from apical to basal dissemination coincides with a profound reorganization of the microtubule cytoskeleton, which in turn prevents the contractile ring repositioning that is required to support extrusion towards the apical surface. While the basal extrusion of cells harbouring NLP-induced centrosome aberrations requires exogenously induced cell damage, structural centrosome aberrations induced by excess CEP131 trigger the spontaneous dissemination of dying cells towards the basal surface from MDCK cysts. Thus, similar to oncogenic mutations, structural centrosome aberrations can favour basal extrusion of damaged cells from polarized epithelia. Assuming that additional mutations may promote cell survival, this process could sensitize epithelia to disseminate potentially metastatic cells.

TheDrosophila ribbongene encodes a nuclear BTB domain protein that promotes epithelial migration and morphogenesis

Development ◽  
2001 ◽  
Vol 128 (23) ◽  
pp. 4923-4933 ◽  
Author(s):  
Katherine Shim ◽  
Kimberly J. Blake ◽  
Joseph Jack ◽  
Mark A. Krasnow
Keyword(s):  
Apical Cell ◽  
Basal Membrane ◽  
Binding Motif ◽  
Apical Surface ◽  
Basal Surface ◽  
Tracheal System ◽  
Epithelial Migration ◽  
Tracheal Cell ◽  
Branch Formation ◽  
Membrane Protrusions

During development of the Drosophila tracheal (respiratory) system, the cell bodies and apical and basal surfaces of the tracheal epithelium normally move in concert as new branches bud and grow out to form tubes. We show that mutations in the Drosophila ribbon (rib) gene disrupt this coupling: the basal surface continues to extend towards its normal targets, but movement and morphogenesis of the tracheal cell bodies and apical surface is severely impaired, resulting in long basal membrane protrusions but little net movement or branch formation. rib mutant tracheal cells are still responsive to the Branchless fibroblast growth factor (FGF) that guides branch outgrowth, and they express apical membrane markers normally. This suggests that the defect lies either in transmission of the FGF signal from the basal surface to the rest of the cell or in the apical cell migration and tubulogenesis machinery. rib encodes a nuclear protein with a BTB/POZ domain and Pipsqueak DNA-binding motif. It is expressed in the developing tracheal system and other morphogenetically active epithelia, many of which are also affected in rib mutants. We propose that Rib is a key regulator of epithelial morphogenesis that promotes migration and morphogenesis of the tracheal cell bodies and apical surface and other morphogenetic movements.

Blastokinesis in embryos of the bug, Pyrrhocoris apterus.

Development ◽  
1981 ◽  
Vol 61 (1) ◽  
pp. 35-49
Author(s):  
Eugenie C. Enslee ◽  
Lynn M. Riddiford
Keyword(s):  
Cell Shape ◽  
Shape Change ◽  
Secretory Granules ◽  
Tube Formation ◽  
Apical Surface ◽  
Final Position ◽  
Basal Surface ◽  
Pyrrhocoris Apterus ◽  
Cell Shape Change ◽  
Dense Zone

In the bug, Pyrrhocoris apterus, blastokinesis (a reversal of the position of the embryo within the egg) is seen to involve contraction of the serosa that is attached to the embryo's head. As the serosal cells change from squamous to columnar in the course of blastokinesis, a dense zone of microfilaments appears just under the apical surface. Many apical protrusions develop above this zone. After the embryo is in its final position the zone disappears and later the cells degenerate. Laterally, the serosal cells are connected by belt desmosornes, septate junctions and gap junctions. As blastokinesis progresses, more lateral surface is recruited below them from the original basal surface. Microtubules running parallel to the plasma membrane are seen near the apical microfilaments and along other surfaces of the cell. Secretory granules are evident both within serosal cells and along the apical surface, probably providing a lubricant for movement against the chorion. Yolk cells are common basal to the serosa, possibly mobilizing nutrients for it. This study of blastokinesis in Pyrrhocoris provides a dramatic example of cell shape change that is correlated with the appearance of microfilaments. In its details blastokinesis is comparable to morphogenetic events such as amphibian neural tube formation and ascidian metamorphosis.

scholarly journals Selective anchoring in the specific plasma membrane domain: a role in epithelial cell polarity.

1988 ◽  
Vol 107 (6) ◽  
pp. 2363-2376 ◽  
Author(s):  
P J Salas ◽  
D E Vega-Salas ◽  
J Hochman ◽  
E Rodriguez-Boulan ◽  
M Edidin
Keyword(s):  
Plasma Membrane ◽  
Epithelial Cell ◽  
Fluorescence Recovery ◽  
Apical Surface ◽  
Collagen Gels ◽  
Surface Polarity ◽  
Basal Surface ◽  
Apical Domain ◽  
Cell Biol ◽  
In Cells

We have studied the role of restrictions to lateral mobility in the segregation of proteins to apical and basolateral domains of MDCK epithelial cells. Radioimmunoassay and semiquantitative video analysis of immunofluorescence on frozen sections showed that one apical and three basolateral glycoproteins, defined by monoclonal antibodies and binding of beta-2-microglobulin, were incompletely extracted with 0.5% Triton X-100 in a buffer that preserves the cortical cytoskeleton (Fey, E. G., K. M. Wan, and S. Penman. 1984. J. Cell Biol. 98:1973-1984; Nelson, W. T. and P. J. Veshnock. 1986. J. Cell Biol. 103:1751-1766). The marker proteins were preferentially extracted from the "incorrect" domain (i.e., the apical domain for a basolateral marker), indicating that the cytoskeletal anchoring was most effective on the "correct" domain. The two basolateral markers were unpolarized and almost completely extractable in cells prevented from establishing cell-cell contacts by incubation in low Ca++ medium, while an apical marker was only extracted from the basal surface under the same conditions. Procedures were developed to apply fluorescent probes to either the apical or the basolateral surface of live cells grown on native collagen gels. Fluorescence recovery after photobleaching of predominantly basolateral antigens showed a large percent of cells (28-52%) with no recoverable fluorescence on the basal domain but normal fluorescence recovery on the apical surface of most cells (92-100%). Diffusion coefficients in cells with normal fluorescence recovery were in the order of 1.1 x 10(-9) cm2/s in the apical domain and 0.6-0.9 x 10(-9) cm2/s in the basal surface, but the difference was not significant. The data from both techniques indicate (a) the existence of mobile and immobile protein fractions in both plasma membrane domains, and (b) that linkage to a domain specific submembrane cytoskeleton plays an important role in the maintenance of epithelial cell surface polarity.

scholarly journals Characterization of apical and basal thiol-disulfide redox regulation in human colonic epithelial cells

2010 ◽  
Vol 299 (2) ◽  
pp. G523-G530 ◽  
Author(s):  
Yanci O. Mannery ◽  
Thomas R. Ziegler ◽  
Li Hao ◽  
Yvonne Shyntum ◽  
Dean P. Jones
Keyword(s):  
Redox Regulation ◽  
Membrane Surface ◽  
Surface Proteins ◽  
Disulfonic Acid ◽  
Epithelial Cell Line ◽  
Apical Surface ◽  
Synthesis Inhibitor ◽  
Basal Surface ◽  
Permeable Membrane

Control of extracellular thiol-disulfide redox potential (Eh) is necessary to protect cell surface proteins from external oxidative and reductive stresses. Previous studies show that human colonic epithelial Caco-2 cells, which grow in cell culture with the apical surface exposed to the medium, regulate extracellular cysteine/cystine Eh to physiological values (approximately −80 mV) observed in vivo. The present study tested whether extracellular Eh regulation occurs on the basal surface of Caco-2 cells and investigated relevant mechanisms. Experiments were performed with confluent, differentiated cells grown on a permeable membrane surface. Cells were exposed to an oxidizing potential (0 mV) using a fixed cysteine-to-cystine ratio, and culture medium was sampled over time for change in Eh. Regulation of extracellular thiol-disulfide Eh on the basal domain was faster, and the extent of change at 24 h was greater than on the apical surface. Mechanistic studies showed that redox regulation on the basal surface was partially sodium dependent and inhibited by extracellular lysine, a competitive inhibitor of cystine transport by the y+L system and by quisqualic acid, an inhibitor of the xc− system. Studies using the thiol-reactive alkylating agent 4-acetamido-4′-maleimidylstilbene-2,2′-disulfonic acid and the glutathione synthesis inhibitor buthionine sulfoximine showed that extracellular redox regulation was not attributable to plasma membrane cysteine/cystine interconversion or intracellular glutathione, respectively. Thus the data show that redox regulation occurs at different rates on the apical and basal surfaces of the polarized Caco-2 epithelial cell line and that the y+L and xc− systems function in extracellular cysteine/cystine redox regulation on the basal surface.

Comparison of apical and basal surfaces of confluent endothelial cells: patch-clamp and viral studies

1992 ◽  
Vol 263 (3) ◽  
pp. C573-C583 ◽  
Author(s):  
M. Colden-Stanfield ◽  
E. B. Cramer ◽  
E. K. Gallin
Keyword(s):  
Endothelial Cells ◽  
Patch Clamp ◽  
Single Channel ◽  
Cell Types ◽  
K Channel ◽  
Virus Protein ◽  
Apical Surface ◽  
Cellular Polarity ◽  
Virus Budding ◽  
Basal Surface

The distribution of inwardly rectifying (Ki) and calcium-activated (KCa) potassium channels on the apical and basal surfaces of bovine aortic endothelial cells (BAECs) was examined by inverting BAEC monolayers onto polylysine-coated cover slips. To monitor cellular polarity, we examined human red blood cell adherence (hemadsorption) to the influenza virus protein, hemagglutinin (HA), and virus budding on the surface of infected BAECs. Hemadsorption and virus budding occurred on the apical surface but were not apparent on the basal surface of monolayers 1 and 5 h after inversion, although cellular HA antigen localization confirmed that all monolayers were infected. In contrast, by 9.5 and 24 h after inversion, hemadsorption was evident on the “new” apical surface. Single-channel patch-clamp analysis revealed the presence of both Ki and KCa channels on the apical surface and basal surface of BAEC monolayers 2-5 h after inversion. K channel conductance and kinetics were similar regardless of the surface monitored. This nonenzymatic mechanical technique of exposing the basal surface of endothelium provides a useful tool to study the distribution of ion channels in endothelium and in other polarized cell types grown in tissue culture.

A Study on the Fine Structure of the Lateral Line Organ of the Sea Eel

1973 ◽  
Vol 31 ◽  
pp. 648-649
Author(s):  
K. Hama
Keyword(s):  
Fine Structure ◽  
Electron Microscope ◽  
Lateral Line ◽  
Low Frequency ◽  
Sensory Cells ◽  
Apical Surface ◽  
Voltage Electron ◽  
Sensory Epithelia ◽  
Low Frequency Vibration ◽  
Transmission Electron

The lateral line organs of the sea eel consist of canal and pit organs which are different in function. The former is a low frequency vibration detector whereas the latter functions as an ion receptor as well as a mechano receptor.The fine structure of the sensory epithelia of both organs were studied by means of ordinary transmission electron microscope, high voltage electron microscope and of surface scanning electron microscope.The sensory cells of the canal organ are polarized in front-caudal direction and those of the pit organ are polarized in dorso-ventral direction. The sensory epithelia of both organs have thinner surface coats compared to the surrounding ordinary epithelial cells, which have very thick fuzzy coatings on the apical surface.

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