scholarly journals A STUDY OF THE PENETRATION OF MAMMALIAN CELLS BY DEOXYRIBONUCLEIC ACIDS

1961 ◽  
Vol 9 (1) ◽  
pp. 81-91 ◽  
Author(s):  
Ellen Borenfreund ◽  
Aaron Bendich
Keyword(s):  
Nucleic Acids ◽  
Hela Cell ◽  
Perchloric Acid ◽  
Hela Cells ◽  
Mammalian Cells ◽  
Deoxyribonucleic Acid ◽  
Degradation Products ◽  
Dna Bases ◽  
Human Dna ◽  
Nuclear Regions

Tritium-labeled deoxyribonucleic acid (DNA) from pneumococci and from human leukocytes was added to growing cultures of HeLa cells at 37°C. Autoradiography revealed an extensive localization of tritium in the nuclear regions. The label could not be removed by treatment with ribonuclease or dilute perchloric acid, but quantitative removal from the cells could be effected with deoxyribonuclease. Chemical and radioactivity determinations on nucleic acids isolated from the exposed HeLa cells revealed the presence of tritium in all 4 DNA bases. About 12 µg. of tritiated DNA was recovered from 6 x 106 HeLa cells which had been exposed for 24 hours to 240 µg. of the human DNA. From this, it is concluded that the amount of DNA, or its degradation products, taken up by the cells was equivalent to at least 10 per cent of the normal HeLa cell complement.

scholarly journals Higly fusogenic cationic liposomes transiently permeabilize the plasma membrane of HeLa cells

2007 ◽  
Vol 12 (1) ◽  
Author(s):  
Katarzyna Stebelska ◽  
Paulina Wyrozumska ◽  
Jerzy Gubernator ◽  
Aleksander Sikorski
Keyword(s):  
Plasma Membrane ◽  
Nucleic Acids ◽  
Propidium Iodide ◽  
Hela Cells ◽  
Mammalian Cells ◽  
Morphological Changes ◽  
Membrane Integrity ◽  
Cationic Liposomes ◽  
Endosomal Membrane

AbstractCationic liposomes can efficiently carry nucleic acids into mammalian cells. This property is tightly connected with their ability to fuse with negatively charged natural membranes (i.e. the plasma membrane and endosomal membrane). We used FRET to monitor and compare the efficiency of lipid mixing of two liposomal preparations — one of short-chained diC14-amidine and one of long-chained unsaturated DOTAP — with the plasma membrane of HeLa cells. The diC14-amidine liposomes displayed a much higher susceptibility to lipid mixing with the target membranes. They disrupted the membrane integrity of the HeLa cells, as detected using the propidium iodide permeabilization test. Morphological changes were transient and essentially did not affect the viability of the HeLa cells. The diC14-amidine liposomes were much more effective at either inducing lipid mixing or facilitating transfection.

scholarly journals THE INTERACTION BETWEEN TOXOPLASMA GONDII AND MAMMALIAN CELLS

1972 ◽  
Vol 136 (5) ◽  
pp. 1157-1172 ◽  
Author(s):  
Thomas C. Jones ◽  
Shirley Yeh ◽  
James G. Hirsch
Keyword(s):  
Electron Microscopy ◽  
Toxoplasma Gondii ◽  
Cell Membrane ◽  
Hela Cell ◽  
Cell Cultures ◽  
Hela Cells ◽  
Generation Time ◽  
Mammalian Cells ◽  
Cell Types ◽  
Special Procedure

Macrophage, fibroblast, and HeLa cell cultures have been infected with Toxoplasma gondii, and observations have been made on parasite entry and fate. A special procedure was devised for studying the entry of toxoplasmas by electron microscopy. Toxoplasmas were centrifuged onto the cells in the cold; fixation 1–3 min after warming yielded specimens showing numerous examples of parasites in the process of entering cells. The mechanism of entry into macrophages, fibroblasts, and HeLa cells was in all cases by phagocytosis. Micropseudopods were extended by the cells to envelop the attached parasites in a typical phagocytic vacuole. Apparently the toxoplasmas stimulated this response of HeLa cells and fibroblasts, cell types not usually phagocytic. No instance was seen of penetration of toxoplasmas through the cell membrane, or of parasites located free in the cytoplasm. Essentially all of the toxoplasmas that entered HeLa cells divided with a generation time of 9 hr; the parasites formed large rosettes situated in vacuoles, eventually leading to host cell rupture. Macrophages took in larger numbers of toxoplasmas than did HeLa cells, but approximately half of the parasites inside of macrophages degenerated within a few hours. The surviving toxoplasmas in macrophages divided every 8 hr, forming rosettes and eventually rupturing the cells.

Wirkung von Lithium- und Rhodanidionen auf den Nukleinsäure-Stoffwechsel von Tetrahymena pyriformis, normalen und neoplastischen Säugerzellen / Effect of Lithium and Thiocyanate Ions on the Metabolism of Nucleic Acids of Tetrahymena pyriformis, Normal and Neoplastic Mammalian Cells

1973 ◽  
Vol 28 (7-8) ◽  
pp. 460-462 ◽  
Author(s):  
Klaus Wayss ◽  
Manfred Volm
Keyword(s):  
Nucleic Acids ◽  
Dna Synthesis ◽  
Tumor Cells ◽  
Hela Cells ◽  
Mammalian Cells ◽  
Tetrahymena Pyriformis ◽  
Ascites Tumor ◽  
Yoshida Sarcoma ◽  
Normal Cells ◽  
I Cells

An antagonistic influence of lithium and thiocyanate ions on the metabolism of nucleic acids has been demonstrated in Tetrahymena pyriformis. This effect corresponds to morphogenetic observations on other ciliates. Similar investigations on mammalian cells (L-cells, CV I-cells, Chang-livercells, HeLa-cells, and ascites tumor cells of Walker-carcinosarcoma 256, Yoshida-sarcoma, Zajdelahepatoma) showed, in contrast to the results in Tetrahymena, no antagonistic influence of lithium and thiocyanate ions: Both ions inhibit the DNA-synthesis, in tumor cells as well as in normal cells.

Nuclear-Associated Plasmid, But Not Cell-Associated Plasmid, is Correlated With Transgene Expression in Cultured Mammalian Cells

2000 ◽  
Author(s):  
Molly B. James ◽  
Todd D. Giorgio
Keyword(s):  
Hela Cell ◽  
Hela Cells ◽  
Plasmid Dna ◽  
Mammalian Cells ◽  
Transgene Expression ◽  
Quantitative Method ◽  
Fluorescent Protein ◽  
Cmv Promoter ◽  
Green Fluorescent ◽  
Plasmid Delivery

Abstract Intracellular plasmid is rapidly incorporated into the nucleus of HeLa cells following cationic lipoplex transfection. CV1 cells are less effective in translocating plasmid to the nucleus and also express less transgene than HeLa cells. Cultured HeLa and CV1 cells and corresponding isolated nuclei were analyzed after transfection of a Cy3 labeled pGreenLantern plasmid (Cy3-pGL). Flow cytometry was used to measure both plasmid delivery and transgene expression from the plasmid encoding a CMV promoter driven green fluorescent protein. During transfection, HeLa cells rapidly incorporated the plasmid, reaching a maximum of 80% Cy3-pGL positive cells 8 hours post-transfection. The average Cy3-pGL positive HeLa cell contained approximately 2470 plasmid copies. 48% of the nuclei isolated from the transfected HeLa cells were positive for the plasmid marker after 8 hours. In contrast to HeLa cells, fewer CV1 cells and CV1 nuclei incorporated plasmid DNA with peak transfection occurring after 12 hours for 36% of the cells and after 8 hours for 12% of the nuclei. However, the average Cy3-pGL positive CV1 cell did not have a significantly different number of total cellular plasmid copies than the average positive HeLa cell. CV1 nuclei, however, had half as much plasmid as HeLa nuclei. HeLa cells are more efficient than CV1 cells at transporting plasmid from the cytoplasm to the nucleus. This study demonstrates the use of a novel quantitative method to study plasmid transport from the cytoplasm to nucleus and the effect on transgene expression.

scholarly journals HeLa cells extend and internalize pseudopodia during active invasion by Trypanosoma cruzi trypomastigotes

1992 ◽  
Vol 101 (4) ◽  
pp. 895-905
Author(s):  
S. Schenkman ◽  
R.A. Mortara
Keyword(s):  
Trypanosoma Cruzi ◽  
Hela Cell ◽  
Hela Cells ◽  
Mammalian Cells ◽  
Protozoan Parasite ◽  
Cytochalasin D ◽  
Cytoplasmic Vacuoles ◽  
Membrane Protrusions ◽  
Insight Into

We show here that HeLa cell microfilaments can be stained by phalloidin at the sites of invasion of Trypanosoma cruzi trypomastigotes, one of the infective stages of this protozoan parasite. Concurrently, a projection of the HeLa cell plasmalemma encircles invading parasites. This plasmalemma projection is further internalized and entire membrane protrusions containing parasites are found within cytoplasmic vacuoles of the host cell. Neither the microfilament staining around invading parasites nor the plasmalemma extension is inhibited by cytochalasin D, a drug that is unable to prevent trypomastigote entry into HeLa cells. The internalization of the membrane expansion, however, is blocked by the drug. These novel observations indicate that although the driving force for T. cruzi penetration comes from the parasite, the cortical target cytoskeleton of the target cell is concomitantly modified. The molecular characterization of this phenomenon may provide a new insight into the understanding of the mechanisms involved in the active penetration of T. cruzi into mammalian cells.

scholarly journals Differential Effect of Ethidium Bromide and Cytosine Arabinoside on Mitochondrial and Nuclear DNA Synthesis in HeLa Cells

1972 ◽  
Vol 27 (8) ◽  
pp. 989-991 ◽  
Author(s):  
Kenzo Kato ◽  
Klaus D. Radsak ◽  
Hilary Koprowski
Keyword(s):  
Hela Cell ◽  
Dna Synthesis ◽  
Ethidium Bromide ◽  
Hela Cells ◽  
Cytosine Arabinoside ◽  
Differential Effect ◽  
Mammalian Cells ◽  
Nuclear Dna ◽  
Circular Dna ◽  
Isopycnic Centrifugation

The effect of ethidium bromide (EB) on the synthesis of circular DNA of mammalian cells was studied by isopycnic centrifugation in a CsCl-EB solution. EB (0.1—0.5 μg/ml) interferes with the synthesis of newly-formed circular DNA of HeLa cell mitochondria and causes degradation of the pre-existing circular DNA, as well. Under the same conditions, nuclear DNA synthesis was not inhibited. This effect was not reversible at a concentration of 0.5 μg EB/ml or more. Cytosine arabinoside (ara-C) did not exhibit an effect similar to that of EB.

Use of Uranium-Labeled Antibodies for Electron Microscopic Localization of Various Antigens in Mammalian Cells

1967 ◽  
Vol 25 ◽  
pp. 136-137
Author(s):  
J. P. Petrali ◽  
E. J. Donati ◽  
L. A. Sternberger
Keyword(s):  
Endoplasmic Reticulum ◽  
Hela Cells ◽  
Mammalian Cells ◽  
Specific Antiserum ◽  
Electron Microscopic ◽  
E Coli ◽  
Cytoplasmic Membranes ◽  
Viral Progeny ◽  
Ultrathin Sections ◽  
Electron Microscopic Localization

Specific contrast is conferred to subcellular antigen by applying purified antibodies, exhaustively labeled with uranium under immunospecific protection, to ultrathin sections. Use of Seligman’s principle of bridging osmium to metal via thiocarbohydrazide (TCH) intensifies specific contrast. Ultrathin sections of osmium-fixed materials were stained on the grid by application of 1) thiosemicarbazide (TSC), 2) unlabeled specific antiserum, 3) uranium-labeled anti-antibody and 4) TCH followed by reosmication. Antigens to be localized consisted of vaccinia antigen in infected HeLa cells, lysozyme in monocytes of patients with monocytic or monomyelocytic leukemia, and fibrinogen in the platelets of these leukemic patients. Control sections were stained with non-specific antiserum (E. coli).In the vaccinia-HeLa system, antigen was localized from 1 to 3 hours following infection, and was confined to degrading virus, the inner walls of numerous organelles, and other structures in cytoplasmic foci. Surrounding architecture and cellular mitochondria were unstained. 8 to 14 hours after infection, antigen was localized on the outer walls of the viral progeny, on cytoplasmic membranes, and free in the cytoplasm. Staining of endoplasmic reticulum was intense and focal early, and weak and diffuse late in infection.

scholarly journals Transcription of 4′-thioDNA templates to natural RNA in vitro and in mammalian cells

2015 ◽  
Vol 51 (37) ◽  
pp. 7887-7890 ◽  
Author(s):  
Hideto Maruyama ◽  
Kazuhiro Furukawa ◽  
Hiroyuki Kamiya ◽  
Noriaki Minakawa ◽  
Akira Matsuda
Keyword(s):  
Nucleic Acids ◽  
Mammalian Cells ◽  
Genetic Material ◽  
Rna Polymerases ◽  
Chemically Modified ◽  
Biological Studies ◽  
Modified Nucleic Acids

Synthetic chemically modified nucleic acids, which are compatible with DNA/RNA polymerases, have great potential as a genetic material for synthetic biological studies.

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