scholarly journals Channelling of intermediates in the biosynthesis of phosphatidylcholine and phosphatidylethanolamine in mammalian cells

1998 ◽  
Vol 334 (3) ◽  
pp. 511-517 ◽  
Author(s):  
Bellinda A. BLADERGROEN ◽  
Math J. H. GEELEN ◽  
A. Ch. Pulla REDDY ◽  
Peter E. DECLERCQ ◽  
Lambert M. G. VAN GOLDE
Keyword(s):  
Staphylococcus Aureus ◽  
Mammalian Cells ◽  
Glioma Cells ◽  
Rat Hepatocytes ◽  
Cell Types ◽  
General Phenomenon ◽  
Rat Glioma ◽  
Permeabilized Cells ◽  
Metabolic Compartmentation ◽  
Choline Incorporation

Previous studies with electropermeabilized cells have suggested the occurrence of metabolic compartmentation and Ca2+-dependent channeling of intermediates of phosphatidylcholine (PC) biosynthesis in C6 rat glioma cells. With a more accessible permeabilization technique, we investigated whether this is a more general phenomenon also occurring in other cell types and whether channeling is involved in phosphatidylethanolamine (PE) synthesis as well. C6 rat glioma cells, C3H10T½ fibroblasts and rat hepatocytes were permeabilized with Staphylococcus aureus α-toxin, and the incorporation of the radiolabelled precursors choline, phosphocholine (P-choline), ethanolamine and phosphoethanolamine (P-EA) into PC and PE were measured both at high and low Ca2+ concentrations. In glioma cells, permeabilization at high Ca2+ concentration did not affect [14C]choline or [14C]P-choline incorporation into PC. However, reduction of free Ca2+ in the medium from 1.8 mM to < 1 nM resulted in a dramatic increase in [14C]P-choline incorporation into permeabilized cells, whereas [14C]choline incorporation remained unaffected. Also, in fibroblasts, reduction of extracellular Ca2+ increased [14C]P-choline and [14C]P-EA incorporation into PC and PE respectively. In hepatocytes, a combination of α-toxin and low Ca2+ concentration severely impaired [14C]choline incorporation into PC. Therefore, α-toxin-permeabilized hepatocytes are not a good model in which to study channeling of intermediates in PC biosynthesis. In conclusion, our results indicate that channeling is involved in PC synthesis in glioma cells and fibroblasts. PE synthesis in fibroblasts is also at least partly dependent on channeling.

Zinc Induces Apoptosis That Can Be Suppressed by Lanthanum in C6 Rat Glioma Cells

2001 ◽  
Vol 382 (8) ◽  
pp. 1227-1234 ◽  
Author(s):  
Hajo Haase ◽  
Wim Wätjen ◽  
Detmar Beyersmann
Keyword(s):  
Membrane Potential ◽  
Protein Kinase ◽  
Mitochondrial Membrane Potential ◽  
Mammalian Cells ◽  
Mitochondrial Membrane ◽  
Glioma Cells ◽  
Zinc Uptake ◽  
Zinc Toxicity ◽  
C6 Cells ◽  
Rat Glioma

Abstract Zinc ions have both essential and toxic effects on mammalian cells. Here we report the ability of zinc to act as an inducer of apoptosis in C6 rat glioma cells. Incubation with 150 to 300 M ZnCl2 caused cell death that was characterized as apoptotic by internucleosomal DNA fragmentation, formation of apoptotic bodies, nuclear fragmentation and breakdown of the mitochondrial membrane potential. On the other hand, zinc deprivation by the membrane permeable chelator TPEN [N,N,N,N,tetrakis (2-pyridylmethyl)ethylenediamine] also induced programmed death in this cell line, indicating the existence of intracellular zinc levels below and above which apoptosis is induced. Zincinduced apoptosis in C6 cells was independent of major signaling pathways (protein kinase C, mitogen activated protein kinase and guanylate cyclase) and protein synthesis, but was increased by facilitating zinc uptake with the ionophore pyrithione. Lanthanum(III)chloride was also able to increase the net zinc uptake, but nevertheless apoptotic features and zinc toxicity were reduced. Remarkably, lanthanum suppressed the zincinduced breakdown of the mitochondrial membrane potential. We conclude that in C6 cells lanthanum acts in two different ways, as a promoter of net zinc uptake and as a suppressor of zincinduced apoptosis.

Ultrastructural Changes in Three Different Mammalian Cells Following Ultraviolet Laser Irradiation

1972 ◽  
Vol 30 ◽  
pp. 350-351
Author(s):  
K. Shankar Narayan ◽  
Kailash C. Gupta ◽  
Tohru Okigaki
Keyword(s):  
Ultraviolet Light ◽  
Mammalian Cells ◽  
Biological Effects ◽  
Survival Rates ◽  
Chinese Hamster ◽  
Cell Types ◽  
Differential Sensitivity ◽  
Ultrastructural Changes ◽  
Ultraviolet Laser

The biological effects of short-wave ultraviolet light has generally been described in terms of changes in cell growth or survival rates and production of chromosomal aberrations. Ultrastructural changes following exposure of cells to ultraviolet light, particularly at 265 nm, have not been reported.We have developed a means of irradiating populations of cells grown in vitro to a monochromatic ultraviolet laser beam at a wavelength of 265 nm based on the method of Johnson. The cell types studies were: i) WI-38, a human diploid fibroblast; ii) CMP, a human adenocarcinoma cell line; and iii) Don C-II, a Chinese hamster fibroblast cell strain. The cells were exposed either in situ or in suspension to the ultraviolet laser (UVL) beam. Irradiated cell populations were studied either "immediately" or following growth for 1-8 days after irradiation.Differential sensitivity, as measured by survival rates were observed in the three cell types studied. Pattern of ultrastructural changes were also different in the three cell types.

A Comparison of Plasminogen Activators Derived from Rat Plasma, Primary Rat Hepatocytes and Isolated Perfused Rat Liver

1982 ◽  
Vol 47 (02) ◽  
pp. 166-172 ◽  
Author(s):  
Yoav Sharoni ◽  
Maria C Topal ◽  
Patricia R Tuttle ◽  
Henry Berger
Keyword(s):  
Rat Liver ◽  
Isoelectric Point ◽  
Rat Hepatocytes ◽  
Cell Types ◽  
Plasminogen Activators ◽  
Rat Plasma ◽  
Isolated Perfused Rat Liver ◽  
Perfused Rat Liver ◽  
Molecular Weights ◽  
Physiological Relevance

SummaryOf the two cell types it was possible to culture from the dissociated rat liver, hepatocytes and Kupffer cells, only the former were fibrinolytically active. Rat hepatocytes during the first 24 hr in culture secreted two plasminogen activators with molecular weights identical to those found in rat plasma, an 80,000-dalton form (PA-80) and a 45,000-dalton form (PA-45). Partially purified preparations of plasminogen activators from both sources were subjected to isoelectric focusing (IEF) to compare characteristics further. There were three distinct peaks of PA-45 in each preparation with isoelectric points of 7.1, 7.2 and 7.4; all electrophoretic forms had the same low affinity to fibrin. PA-80 from both sources displayed similar IEF profiles with forms ranging from pH values of 7 to 8, all with the same high affinity to fibrin. The major form of PA-80 in the plasma preparation had an isoelectric point of 7.9 whereas that in the hepatocyte preparation had an isoelectric point of 7.6. The isolated perfused rat liver was also shown to produce both PA-80 and PA-45 emphasizing the physiological relevance of the findings with hepatocytes. It is concluded that in the rat hepatocytes contribute to the plasma profile with regard to the plasminogen activator content.

effect of ginsenoside Rd on nitric oxide system induced by lipopolysaccharide plus TNF-α in C6 rat glioma cells

2003 ◽  
Vol 26 (5) ◽  
pp. 375-382 ◽  
Author(s):  
Seong-Soo Choi ◽  
Jin-Koo Lee ◽  
Eun-Jung Han ◽  
Ki-Jung Han ◽  
Han-Kyu Lee ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Glioma Cells ◽  
Oxide System ◽  
Rat Glioma ◽  
Ginsenoside Rd ◽  
Tnf Α ◽  
Nitric Oxide System

scholarly journals Effects of taurolithocholate, a Ca2+-mobilizing agent, on cell Ca2+ in rat hepatocytes, human platelets and neuroblastoma NG108-15 cell line

1991 ◽  
Vol 273 (1) ◽  
pp. 153-160 ◽  
Author(s):  
J F Coquil ◽  
B Berthon ◽  
N Chomiki ◽  
L Combettes ◽  
P Jourdon ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Bile Acid ◽  
Cell Line ◽  
Rat Liver ◽  
Neuronal Cell ◽  
Rat Hepatocytes ◽  
Cell Types ◽  
Liver Cells ◽  
Human Platelets ◽  
Rat Liver Cells

The monohydroxy bile acid taurolithocholate permeabilizes the endoplasmic reticulum to Ca2+ in rat liver cells. To assess whether this action on the endoplasmic reticulum was restricted to this tissue, the effects of bile acid were investigated in two cell types quite unrelated to rat hepatocyte, namely human platelets and neuronal NG108-15 cell line. The results showed that taurolithocholate (3-100 microM) had no effect on free cytosolic [Ca2+] in human platelets and NG108-15 cells. whereas it increased it from 180 to 520 nM in rat hepatocytes. In contrast, in cells permeabilized by saponin, taurolithocholate initiated a profound release of the stored Ca2+ from the internal Ca2+ pools in the three cell types. The bile acid released 90% of the Ca2+ pools, with rate constants of about 5 min-1 and half-maximal effects at 15-30 microM. The results also showed that, in contrast with liver cells, which displayed an influx of [14C]taurolithocholate of 2 nmol/min per mg, human platelets and the neuronal cell line appeared to be resistant to [14C]taurolithocholate uptake. The influx measured in these latter cells was about 100-fold lower than in rat liver cells. Taken together, these data suggest that human platelets and NG108-15 cells do not possess the transport system for concentrating monohydroxy bile acids into cells. However, they show that human platelets and neuronal NG108-15 possess, in common with liver cells, the intracellular system responsible for taurolithocholate-mediated Ca2+ release from internal stores.

scholarly journals EEA1, a Tethering Protein of the Early Sorting Endosome, Shows a Polarized Distribution in Hippocampal Neurons, Epithelial Cells, and Fibroblasts

2000 ◽  
Vol 11 (8) ◽  
pp. 2657-2671 ◽  
Author(s):  
Jean M. Wilson ◽  
Meltsje de Hoop ◽  
Natasha Zorzi ◽  
Ban-Hock Toh ◽  
Carlos G. Dotti ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Mammalian Cells ◽  
Hippocampal Neurons ◽  
Cell Types ◽  
Early Endosomes ◽  
Filamentous Material ◽  
Endocytic Vesicles ◽  
Fibroblastic Cells ◽  
Darby Canine Kidney ◽  
Endocytic Pathways

EEA1 is an early endosomal Rab5 effector protein that has been implicated in the docking of incoming endocytic vesicles before fusion with early endosomes. Because of the presence of complex endosomal pathways in polarized and nonpolarized cells, we have examined the distribution of EEA1 in diverse cell types. Ultrastructural analysis demonstrates that EEA1 is present on a subdomain of the early sorting endosome but not on clathrin-coated vesicles, consistent with a role in providing directionality to early endosomal fusion. Furthermore, EEA1 is associated with filamentous material that extends from the cytoplasmic surface of the endosomal domain, which is also consistent with a tethering/docking role for EEA1. In polarized cells (Madin-Darby canine kidney cells and hippocampal neurons), EEA1 is present on a subset of “basolateral-type” endosomal compartments, suggesting that EEA1 regulates specific endocytic pathways. In both epithelial cells and fibroblastic cells, EEA1 and a transfected apical endosomal marker, endotubin, label distinct endosomal populations. Hence, there are at least two distinct sets of early endosomes in polarized and nonpolarized mammalian cells. EEA1 could provide specificity and directionality to fusion events occurring in a subset of these endosomes in polarized and nonpolarized cells.

Growth inhibition by sialosyl cholesterol of rat glioma cells

1990 ◽  
Vol 17 (1) ◽  
pp. 93-100 ◽  
Author(s):  
Sumiko Abe-Dohmae ◽  
Jin-Ichi Ito ◽  
Taiji Kato ◽  
Ryo Tanaka
Keyword(s):  
Growth Inhibition ◽  
Glioma Cells ◽  
Rat Glioma
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