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Volume 8 (1983)
- Issue 4 Pages 315-
- Issue 3 Pages 199-
- Issue 2 Pages 91-
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Volume 8, Issue 3
Displaying 1-12 of 12 articles from this issue
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Yuko Takii, Mieko Higashi, Yukito Masamune, Fumiaki Ito1983 Volume 8 Issue 3 Pages 199-209
Published: 1983
Released on J-STAGE: April 18, 2008
JOURNAL FREE ACCESSLow density lipoprotein (LDL) and high density lipoprotein (HDL) were purified from normal human serum by KBr density gradient centrifugation and gel filtration through Sepharose 4B. LDL reversibly inhibited proliferation of Swiss/3T3 cells, whereas HDL had no inhibitory effect on cell growth. The LDL-induced inhibition was LDL-dose dependent and was reversed by the addition of mevalonate, a product of the reaction of 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase (mevalonate: NADP+ oxidore ductase (CoA-acylating), EC 1.1.1.34). These data suggest that a specific reduction in the activity of HMG-CoA reductase produced by the addition of LDL is the main cause of the inhibition of cell proliferation. Studies of the effect of LDL on the cell cycle showed that it inhibited the entry of cells arrested in G0/G1 into the S phase but that it did not affect the transition of cells at the G1/S boundary into the M phase. The cell cycle of 3T3 is arrested solely in G1 by LDL.View full abstractDownload PDF (1026K) -
Yuko Takii, Yukito Masamune, Fumiaki Ito1983 Volume 8 Issue 3 Pages 211-221
Published: 1983
Released on J-STAGE: April 18, 2008
JOURNAL FREE ACCESSWe previously showed that low density lipoprotein (LDL) induces an early decrease in the thymidine-transport rate and subsequently inhibits cell proliferation. We now have demonstrated that a dose-dependent decrease in the rate of thymidine transport was found in all the cell lines examined irrespective of their sensitivity to the inhibitory effect of LDL on cell growth. Thus, inhibition of both transport and cell growth by LDL are not necessarily coupled. In contrast, 3-O-methyl-D-glucose transport was not affected by an addition of LDL.
The specific inhibition of transport was not suppressed by an addition of chloroquine. Thus, degradation of LDL within the lysosome was not required for LDL to inhibit thymidine transport. A mixture of lipids extracted from LDL was as inhibitory as LDL in the various types of cells examined. Calf serum also prevented the inhibitory effect of both LDL and its lipid constituents equally. Phosphatidylcholine produced no decrease in thymidine transport, but cholesterol inhibited it. We concluded that LDL-associated lipids, part-icularly cholesterol, play an essential role in the LDL-induced decrease of transport.View full abstractDownload PDF (959K) -
Kazuki Sato, Akira Kawahara, Minoru Amano1983 Volume 8 Issue 3 Pages 223-232
Published: 1983
Released on J-STAGE: April 18, 2008
JOURNAL FREE ACCESSThe effect of estradio1-17β on RNA synthesis and the amounts of total RNA and polyadenylic acid were determined in primary cultures of Xenopus laevis liver parenchymal cells. Results showed that estradiol did not alter the RNA content significantly; control cells contained 11.9±0.34 μg and estradiol-treated cells 12.4±0.17 μg per 106 cells on day 2 of estradiol treatment, and 22.0±0.61 μg and 24.0±1.09 μg on day 5. Hybridization with [3H]poly(U) revealed that estradiol increased the poly (A) content about 1.2-fold more than in the controls on day 2 and 1.6-fold on day 5 of estradiol treatment. The actual rate of RNA synthesis was estimated from analyses of the kinetics of [3H]adenosine incorporation into the ATP pool and into RNA. The initial rate of incorporation of ATP into RNA on day 5 of estradiol treatment was 29.38 pmol/min/106 cells and the rate of the controls of 29.35. Subsequent accumulation kinetics of [3H]adenosine into RNA showed no difference between estradiol and the control cells. Thus, estradiol did not alter the rate of total RNA synthesis and the total RNA content significantly, but it did increase the poly(A) content.View full abstractDownload PDF (1076K) -
Takeo Terasaki, Yukio Shimosato, Mitsuo Izawa, Kaneatsu Miyamoto1983 Volume 8 Issue 3 Pages 233-244
Published: 1983
Released on J-STAGE: April 18, 2008
JOURNAL FREE ACCESSRNase-susceptible ionogenic groups on the cell surface membranes of two leukemic and two nonleukemic strains of ascites tumor cells were studied by cell electrophoresis, DEAE-Sephadex A-25 column and paper chromatography, and indirect membrane immunofluorescence. RNase treatment of the nonleukemic ascites tumor cells (Ehrlish ascites tumor and Sarcoma 180) produced a significant reduction in their electrophoretic mobilities. When the cells were labeled with [3H]uridine then incubated with RNase, there was a marked increase in the radioactive nucleotides present in the incubation medium as compared to the results of the experiment with RNase-untreated controls.
Indirect membrane immunofluorescence studies of nonleukemic ascites tumor cells suggest that the sites that react with anti-RNA antibody are distributed diffusely on their surfaces. RNase treatment of these cells markedly reduced their ability to react with the antibody. It thus appears that RNAs are present on the surface membrane of nonleukemic ascites tumor cells and that RNase digests these RNAs, removing negatively charged nucleotides from their electrophoretic surfaces. This results in a reduction in mobility.
In contrast, leukemic ascites cells (L1210 and C1498) incubated with RNase showed no significant change in mobility or in the amount of nucleotides released into the incubation medium. Moreover, no fluorescence was found on the surface of cells examined by indirect membrane immunofluorescence. This suggests that leukemic ascites cells are devoid of RNAs on their surface.View full abstractDownload PDF (2843K) -
Chikako Sato, Kimiko Nishizawa, Hiromu Nakamura, Yoshiyuki Komagoe, Ko ...1983 Volume 8 Issue 3 Pages 245-254
Published: 1983
Released on J-STAGE: April 18, 2008
JOURNAL FREE ACCESSA monoclonal antibody was raised against the highest molecular weight protein associated with microtubules (MAP-1). Its specific binding to MAP-1 was determined by immunoblotting of the gel electrophoretogram of microtubule proteins prepared from porcine brain. The antibody reacted only with MAP-1, not with MAP-2, tau or tubulin. Indirect Immunofluorescent staining by this antibody showed bright intranuclear spots, the centrosome and the faint meshwork of the cytoplasm in several types of cultured mammalian cells; HeLa, PtK2, human skin fibroblasts, mouse melanoma cells, Chinese hamster ovary cells. The nulcear spots in the interphase cells, were replaced by diffuse enhanced fluorescence throughout the cell except for chromosomes during mitosis. They reappeared in late telophase, first in the cytoplasm, late in the nucleus. The punctate pattern of nuclear immunofluorescence was not affected by microtubule-depolymerizing agents. The result that it persisted on residual cell structures after extraction with a high salt concentration buffer containing Triton X-100 followed by digestion with DNase I and RNase A suggests that the antigen is associated with the nuclear skeleton.View full abstractDownload PDF (1031K) -
Wohlfarth Bottermann, Z. Shraideh, Z. Baranowski1983 Volume 8 Issue 3 Pages 255-265
Published: 1983
Released on J-STAGE: April 18, 2008
JOURNAL FREE ACCESSA combined application of 5 mM KCN and 19 μM Ca++-ionophore A-23187 leads to pronounced contractures of plasmodial strands of Physarum polycephalum. The appearance of the contractures is independent of the amount of Ca++ in the external medium. Tensiometric registrations of longitudinal contraction activity (isometric regime) reveal an average tension increase of 50 mp compared with the preceding tension level before the addition of KCN and ionophore.
This high force output during the contracture coincides with a pronounced increase in the number of cytoplasmic actomyosin fibrils. Their ultrastructure is seen as a high lateral density of strictly parallel arranged F-actin filaments; the state of cytoplasmic actomyosin during this isometric contracture corres-ponds to the ultrastructure of isometrically contracted fibrils during the normal contraction-relaxation cycle of this organism.
A simultaneous impediment ofrespiration and Ca++ homeostasis strongly favours a shift of the actin equilibrium to the high polymeric side in the form of fibrils and may thus be used as a preparatory step improving the specimens in the context of other investigations, e.g., for immunocytochemical investigations or for the preparation of cell-free models to be reactivated after extraction procedures.View full abstractDownload PDF (1387K) -
Toshiro Ono, Tadashi Tsujii, Satimaru Senol1983 Volume 8 Issue 3 Pages 267-279
Published: 1983
Released on J-STAGE: April 18, 2008
JOURNAL FREE ACCESSA ferric hydroxide-polyvinyl sulfate colloidal solution (Fe-PVS), prepared by mixing potassium polyvinyl sulfate (PVSK) and ferric hydroxide colloidalsolution was used to study ferritin synthesis in rat peritoneal macrophages. The colloidal particles had spherical electron opaque ferric hydroxide cores with diameters of about 250 nm surrounded by radially arranged fibrous PVS molecules. They also had strong negative electric charges.
Fe-PVS particles injected into the peritoneal cavity were taken up by the macrophages then disintegrated rapidly. In the phagolysosomes the electron opaque ferric hydroxide cores of Fe-PVS were denuded of their PVS frames then decomposed into small 5-6 nm granules 24 to 48 h after injection. These small granules were released from the lysosomes into the hyaloplasm and the myelin figures were found in the lysosomal vacuoles. No reaccumula-tion of granules in lysosomes was found even 3 months later.
The intracellular distribution of ferritin in macrophages demonstrated by the immunocytochemical method showed a pattern similar to that of the small granules formed by the disintegration of Fe-PVS. This means that in rat peritoneal macrophages that contain ingested Fe-PVS particles ferritin first is synthesized in phagolysosomes by the ferric hydroxide cores that conjugate with apoferritin or protein subunits then they are dispersed into the cytoplasm. Two possible pathways for the biosynthesis of ferritin are discussed.View full abstractDownload PDF (1706K) -
Mikio Kan, Noritsugu Yabe, Isao Yamane, Takahiro Hamazaki, Rikuro Sasa ...1983 Volume 8 Issue 3 Pages 281-291
Published: 1983
Released on J-STAGE: April 18, 2008
JOURNAL FREE ACCESSWe examined that growth-promoting activity of two different human albumin (HSA) preparations for human diploid fibroblasts in serum-free RITC 80-7 medium. The activity of one preparation (sample A) was affected markedly by environmental oxygen, whereas the other (sample B) was little affected. Sample B contained ceruloplasmin (Cp) and haptoglobin (Hp) as impurities. To detect the generation of superoxide anion in the media the amount of reduction of cytochrome c that is inhibited by superoxide dismutase (SOD) was determined. In an aerobic environment it was relatively large in comparison with reduction inhibited in a hypoxic environment. Re-duction in the sample A with HSA-supplemented medium was relatively large in comparison with that in sample B with HSA-supplemented medium. The reduction of cytochrome c also was inhibited by Cp (25mg/1) and catalase (4000 units/ml). Moreover, SOD, Cp, catalase and Hp.Hb (but not Hp) partially prevented oxygen-dependent reduction in growth in an aerobic environment when added to sample A HSA-supplemented medium. These results suggest that Cp and Hp. Hb act as an antioxidants in culture.View full abstractDownload PDF (1033K) -
Toshiharu Matsumura, Kiyofumi Masuda, Yoshinori Murakami, Ryuji Konish ...1983 Volume 8 Issue 3 Pages 293-301
Published: 1983
Released on J-STAGE: April 18, 2008
JOURNAL FREE ACCESSFamily trees of rat liver epithelial-like cells in primary culture were obtained by cinemicrographic analysis. With few exceptions the proliferative profiles reconstituted from these family trees showed limited proliferation. This limitation was not due to post-confluence inhibition of proliferation or to nutritional deprivation during time lapse cinemicrography, but to the finite potential of clonal proliferation. In these family trees a cell entered mitosis, incomplete division, death, or a long interphase with no detectable termination. These family trees successfully related the life phases of the individual cells that compose the population to the limited nature of proli-ferative potential as observed in clonal cell populations.View full abstractDownload PDF (2858K) -
Kohzaburo Fujikawa-Yamamoto1983 Volume 8 Issue 3 Pages 303-308
Published: 1983
Released on J-STAGE: April 18, 2008
JOURNAL FREE ACCESSThe cell cycle of HeLa S3 cells synchronized by hydroxyurea was investigated by flow cytometry. Metachromatic fluorochrome acridine orange was used to strain the DNA and RNA of the cells differentially. Periodic changes in the cellular DNA and RNA contents were observed through five cell cycles. The G1 and S phases of synchronized HeLa S3 cells that contained large amounts of RNA became shorter than those of cells that contained smaller amounts of RNA.View full abstractDownload PDF (507K) -
Akinori Masuda, Michihiko Kuwano, Tatsuo Shimada1983 Volume 8 Issue 3 Pages 309-312
Published: 1983
Released on J-STAGE: April 18, 2008
JOURNAL FREE ACCESSChinese hamster V79 cell mutants resistant to compactin (ML236B) were isolated. A resistant clone, MF-2, grown in the presence of 2 μg/ml of ML236B for 1 week showed a 30-fold increase in 3-hydroxy-3-methyl-glutaryl-coenzyme A (HMG-Co A) reductase activity compared to MF-2 grown in the absence of ML236B, and cells grown for 4 weeks showed a 53-fold increase. Apparent ultrastructural changes in thin sections of the MF-2 cells were observed after growth in ML236B: dilated cisternae in the rough endoplasmic reticulum had or did not have flocculated contents ; there was significant distension of perinuclear space; and vesicular inclusion bodies were present in nuclei.View full abstractDownload PDF (573K) -
1983 Volume 8 Issue 3 Pages 313
Published: 1983
Released on J-STAGE: April 18, 2008
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