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  • 1
    Electronic Resource
    Electronic Resource
    A cell-free approach to the study of membrane trafficking in frozen rat brains potentially applicable to frozen autopsy material (1996)
    Springer
    Protoplasma 190 (1996), S. 99-106 
    Details
    ISSN: 1615-6102
    Keywords: Aging ; Alzheimer's disease ; Brain ; Cell-free system ; Membranes ; Membrane trafficking ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary A cell-free transfer system was used to measure capacity of brain membranes to support membrane renewal. To study transfer in brain, radiolabeled donor microsome fractions were prepared using brain slices from rats or frozen human brain autopsy specimens. Acceptor fractions, prepared from fresh or frozen rat brain or frozen human brain autopsy specimens, were immobilized on nitrocellulose. The complete reconstituted transfer system contained ATP plus ATP-regenerating system (or NADH) as a source of energy and brain cytosol. Slices of frozen brain incorporated acetate into membrane lipids with approximately the same efficiency as fresh brains. This efficiency declined with storage at 4 °C but only slowly. Donor fractions labeled with acetate from frozen slices exhibited specific transfer (37 °C minus 4 °C) of labeled membrane lipids with efficiencies comparable to fresh. The acceptor fraction could be prepared either from fresh or frozen material. Transfer was on the average two-fold stimulated by ATP at 37 °C compared to no ATP. Transfer also was stimulated by NADH. Analysis of linear transfer rates between 0 and 30 min revealed no significant effect of delay time or of time of prolonged storage on transfer efficiency beyond an initial decline of ca. 25% observed within the first two weeks after freezing. A decline of transfer was obtained with brains as the animals aged.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01281198
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  • 2
    Electronic Resource
    Electronic Resource
    ATP-dependent cell-free transfer of membrane lipids from nuclei to Golgi apparatus of germinating axes of garden pea (1992)
    Springer
    Protoplasma 170 (1992), S. 1-9 
    Details
    ISSN: 1615-6102
    Keywords: Cell-free transfer ; Lipids ; Nuclei ; Golgi apparatus ; Pea
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary ATP-dependent cell-free transfer of membrane constituents radiolabeled with [14C]acetate, primarily lipids, was demonstrated between isolated nuclei in suspension and purified Golgi apparatus immobilized on nitrocellulose strips prepared from garden pea (Pisum sativum) in the presence of pea cytosol. The ATP-dependent transfer correlated with the ability of the nuclear envelope to form 50–70 nm vesicles and blebs in an ATP-dependent manner. Specific transfer, transfer at 23°C minus transfer at 4°C, was approximately doubled by addition of ATP and was greater for peas germinated for 2 days than for peas germinated for 3 days. ATP plus cytosol-dependent transfer could not be demonstrated using radiolabeled pea nuclei as donor with purified endoplasmic reticulum, plasma membrane, nuclei, mitochondria or amyloplasts as acceptors. The results provide a second example, in addition to transfer between endoplasmic reticulum and Golgi apparatus, where ATP-and temperature-dependent transfer via 50–70 nm transition vesicles can be demonstrated in a cell-free system.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01384452
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  • 3
    Electronic Resource
    Electronic Resource
    Inhibition of the NADH oxidase activity of plasma membranes isolated from xenografts and cell lines by the antitumor sulfonylurea, N-(4-methylphenylsulfonyl)-N′-(4-chlorophenyl)urea (LY 181984) correlates with drug susceptibility of growth (1995)
    Springer
    Protoplasma 184 (1995), S. 203-208 
    Details
    ISSN: 1615-6102
    Keywords: K-ras ; H-ras ; Rat kidney cells ; Antitumor diarylsul-fonylureas ; Human colon xenografts ; HeLa cells
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Inhibition of NADH oxidase activity of plasma membranes isolated from a series of human xenografts and cell lines by the antitumor sulfonylurea, N-(4-methylphenylsulfonyl)-N′-(4-chlorophenyl) urea (LY 181984), correlated with the ability of the sulfonylurea to inhibit cell growth. Growth of rat kidney cells either untransformed or transformed with Kirsten-ras (K-ras) were unaffected by the sulfonylurea. Similarly, the NADH oxidase activity of isolated plasma membranes from K-ras transformed cells was unaffected by LY 181984. In contrast, when transformed with Harvey-ras (H-ras), both growth and NADH oxidase activity were inhibited. With the inactive but structurally related LY 181985 (N-4-methylphenyl-sulfonyl)-N′-(phenyl)urea), neither growth nor plasma membrane NADH oxidase activity of either sulfonylurea-susceptible or -resistant tissues or cell lines was inhibited. Both sulfonylureas were inactive with rat liver plasma membranes but NADH oxidase activity of plasma membranes and growth with HeLa cells was inhibited by the active (LY 181984) but not by the inactive (LY 181985) sulfonylurea. The findings suggest a possible correlation between inhibition of plasma membrane NADH oxidase activity by the antitumor sulfonylureas and their oncolytic action.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01276921
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  • 4
    Electronic Resource
    Electronic Resource
    Golgi apparatus respond to the antitumor sulfonylurea N-(4-methylphenylsulfonyl)-N′-(4-chlorophenyl)urea (LY 181984) in sulfonylurea-susceptible but not in resistant cell lines (1994)
    Springer
    Protoplasma 182 (1994), S. 81-95 
    Details
    ISSN: 1615-6102
    Keywords: Antitumor sulfonylurea ; Golgi apparatus ; Monensin ; Sulfonylurea ; Cultured cells
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Cell lines susceptible or resistant to the active antitumor sulfonylurea [N-(4-methylphenylsulfonyl)-N′-(4-chlorophenyl)-urea] (LY 181984) were treated with 100 μM sulfonylurea for 1 or 3 h followed by monensin for 1 h. With cell lines where growth was inhibited by the active sulfonylurea, swollen Golgi apparatus cisternae following treatment were fewer and smaller than in untreated cells. Overall the volume of monensin-responsive trans cisternae was reduced by about 50% to 75% in cells lines where the antitumor sulfonylurea was growth inhibitory. The swelling response was unaffected by sulfonylurea in sulfonylurea-unresponsive cells. The antitumor-inactive sulfonylurea [N-(4-methylphenylsulfonyl)-N′-(phenyl)urea] (LY 181985) was without effect on cisternal swelling with both susceptible and resistant cell lines. The results suggest a response of the trans Golgi apparatus to the active antitumor sulfonylurea that resulted in reduced acidification of the trans Golgi apparatus cisternae. This response appears to be restricted to susceptible cell lines where growth was inhibited by the active antitumor sulfonylurea but not in resistant cell lines where growth was unaffected by the active antitumor sulfonylurea.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01403470
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  • 5
    Electronic Resource
    Electronic Resource
    Mechanism of killing of HeLa cells by the antitumor sulfonylurea, N-(4-methylphenylsulfonyl)-N′-(4-chlorophenyl)urea (LY 181984) (1995)
    Springer
    Protoplasma 184 (1995), S. 188-195 
    Details
    ISSN: 1615-6102
    Keywords: Antitumor sulfonylurea ; Apoptosis ; pH control ; Growth ; Hela cells
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The antitumor sulfonylureas appear to inhibit both mitochondrial activity in susceptible human colon lines and to inhibit the oxidation of NADH by isolated plasma membrane vesicles from HeLa cells. The results reported here describe the morphological appearance of HeLa cells treated with the antitumor sulfonylurea N-(4-methylphenylsulfonyl)-N′-(4-chlorophenyl)urea (LY181984). The cells remain viable for several days although the rate of increase in cell number is slowed especially at high concentrations of the drug. Cells become smaller with normal nuclei or maintain a normal size but contain multiple or enlarged nuclei. The morphological observations suggest that the drug may somehow interfere with the ability of the cells to enlarge following cytokinesis. Between 72 and 96 h, the cells begin to die. Cell death is accompanied by a condensed and fragmented appearance of the nuclear DNA as revealed by fluorescence microscopy with 4′,6-diamidino-2-phenylindole suggestive of apoptosis. Early transients in loss of pH control (4 min after sulfonylurea addition) and an increase in cytoplasmic calcium (4 h after sulfonylurea addition) were observed but were small and perhaps secondary to the mechanism responsible for the failure of the cells to grow and ensuing cell death.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01276919
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  • 6
    Electronic Resource
    Electronic Resource
    Response of NADH oxidation and growth in K-562 cells to the antitumor sulfonylurea, N-(4-methylphenylsulfonyl)-N′-(4-chlorophenyl)urea (LY181984) (1995)
    Springer
    Protoplasma 188 (1995), S. 151-160 
    Details
    ISSN: 1615-6102
    Keywords: Antitumor sulfonylurea ; NADH oxidase ; Plasma membranes ; Growth ; Golgi apparatus ; Mitochondria ; HeLa cells
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Growth of K-562 cells in culture is inhibited by the antitumor sulfonylureaLY181984 (N-(4-methylphenylsulfonyl)-N′-(4-chlorophenyl)urea) with an ED50 of about 30 μM. LY181984 was shown previously to inhibit NADH oxidation by plasma membranes from HeLa cells and other sources and to influence mitochondrial oxidative phosphorylation. With K-562 cells, NADH oxidation by plasma membranes was transiently stimulated and then inhibited by LY181984. NADH oxidation by whole cells was transiently stimulated and then inhibited by 0.1 to 100 μM LY181984 as well. Both the stimulations and inhibitions of activity were time-dependent. NADH oxidation by lower phase membranes depleted of plasma membranes by aqueous two-phase partition also was inhibited by micromolar and submicromolar concentrations of LY181984. Inhibition did not correlate with mitochondrial presence but rather with membranes that appeared to be fragments of the Golgi apparatus. The oxidation of NADH by whole cells and of plasma membranes that was inhibited by LY181984 was distinguished from mitochondrial NADH oxidation by resistance to inhibition by cyanide and by proceeding under oxygen-depleted conditions or an argon atmosphere. In contrast to the active antitumor agent LY181984, the inactive but chemically-related analog, LY181985 (N-(4-methylphenyl-sulfonyl)-N′-(4-phenylurea), inhibited neither growth nor NADH oxidation with K-562 cells or cell fractions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01280366
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