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Volume 12 (1987)
- Issue 6 Pages 509-
- Issue 5 Pages 407-
- Issue 4 Pages 317-
- Issue 3 Pages 225-
- Issue 2 Pages 141-
- Issue 1 Pages 1-
Volume 12, Issue 5
Displaying 1-10 of 10 articles from this issue
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Role of Superoxide Radicals in Cytotoxic Effects of Fe-NTA on Cultured Normal Liver Epithelial CellsMasayasu Yamada, Tohru Okigaki, Michiyasu Awai1987 Volume 12 Issue 5 Pages 407-420
Published: 1987
Released on J-STAGE: April 18, 2008
JOURNAL FREE ACCESSWe studied the cytotoxic effects of ferric nitrilotriacetate (Fe-NTA) on normal rat liver epithelial cells (RL34) cultured in medium containing 10 % fetal calf serum. Marked cytolysis was present in cells exposed to ?? 25 μg/ml iron of Fe-NTA, but not all the cells exposed to 50 μg/ml iron were lethally injured. The remaining cells showed anomalous growth, namely cell pile-up and aggregation.
Superoxide dismutase inhibited this iron-induced cytotoxicity, whereas catalase, mannitol, dimethyl sulfoxide, and 1, 4-diazabicyclo-[2.2.2] octane did not. RL34 cells exposed to Fe-NTA actually produced a large amount of superoxide radicals (Oτ2), whereas unexposed control cells produced none. Allopurinol inhibited Oτ2 production and prevented cell injury by Fe-NTA. These results show that the injury to cells produced by Fe-NTA depends on the generation of Oτ2, the source of which may be xanthine oxidase.View full abstractDownload PDF (4939K) -
Jun Ninomiva-Tsuii, Yuko Nakahara, Chiho Ito, Taishin Akiyama, Sadahik ...1987 Volume 12 Issue 5 Pages 421-432
Published: 1987
Released on J-STAGE: April 18, 2008
JOURNAL FREE ACCESStsJT60, a temperature-sensitive (ts) G0-mutant cell line from a Fischer rat, grows normally in the exponential growth phase at 34°C and 39.5°C, but when stimulated with fetal bovine serum (FBS), from the G0 phase they reenter the S phase at 34°C but not at 39.5°C. The ts-block was bypassed when G0-arrested tsJT60 cells were stimulated at 39.5°C with FBS plus epidermal growth factor (EGF). The presence of EGF for the first 6 h after serum stimulation caused tsJT60 cells to enter the S phase in the presence of FBS at 39.5°C. When EGF was added 6h after serum stimulation, entrance into the S phase was delayed by about 6 h. The sequential presence of two growth factors, EGF without FBS for 6 h then FBS without EGF, or the reversed sequence, failed to initiate DNA synthesis at 39.5°C. The binding of EGF was not temperature sensitive. The amounts of RNA and protein present doubled after stimulation with both FBS and EGF at 39.5°C. These and other findings suggest that EGF bypasses only some specific event in the entire prereplicative process that operates operating in serum-stimulated cells at 39.5°C.View full abstractDownload PDF (3287K) -
Toshio Ohyama, Yukio Iwaikawa, Miyako Takegami, Michio Ito1987 Volume 12 Issue 5 Pages 433-442
Published: 1987
Released on J-STAGE: April 18, 2008
JOURNAL FREE ACCESSResidual nuclear structures were isolated from Trillium microsporocytes at early meiotic prophase. Relatively well conserved residual nuclear structures were obtained from nuclei isolated in buffer containing 0.1 mM CUSO4. These isolated nuclei were treated with DNaseI, then their chromatin were extracted with 2 M NaCl or dextran sulfate combined with heparin. Cytological and biochemical estimations of the effectiveness of 2 M NaCl and dextran sulfate-heparin on chromatin extraction showed the latter to be the more effective agent. Light microscopy revealed that the residual nuclei retained silver-stainable structures that corresponded to synaptonemal complexes (SCS). The residual nuclei prepared by the treatment with dextran sulfate-heparin consisted mainly of protein that was about 8% of the total nuclear protein present, whereas, about 30% of the nuclear protein was re-tained by nuclei treated with 2 M NaCl.View full abstractDownload PDF (7965K) -
Naoto Yonezawa, Eisuke Nishida, Shigeo Koyasu, Shohei Maekawa, Yasutak ...1987 Volume 12 Issue 5 Pages 443-452
Published: 1987
Released on J-STAGE: April 18, 2008
JOURNAL FREE ACCESSCofilin, a 21kDa actin-binding protein, binds to F-actin in a 1 : 1 molar ratio of cofilin to actin molecule (Nishida, E., S. Maekawa, and H. Sakai, Biochemistry, 23, 5307-5313, 1984) and is capable of controlling actin polymerization and depolymerization in vitro in a pH-sensitive manner (Yonezawa, N., E. Nishida, and H. Sakai, J. Biol. Chem., 260, 14410-14412, 1985). In this study, immunoblot analysis using monospecific antibodies against cofilin showed that cofilin is ubiquitously distributed in a variety of bovine and rat organs and tissues. Cofilin is also present in various cultured cell lines. Indirect immunofluorescence staining of mouse fibroblastic cells and human epidermoid carcinoma cells indicated that cofilin is distributed nearly uniformly in the cytoplasm and is concentrated in ruffling membranes where F-actin is also concentrated as revealed by staining with rhodamine-phalloin. Stress fiber structures were not strongly stained with the anti-cofilin antibody, although stress fiber staining was sometimes observed near the cell periphery in mouse 3T3 cells. These results suggest that the bulk of cofilin may not be associated with F-actin bundles in vivo.View full abstractDownload PDF (958K) -
Tetsuaki Osafune, Jerome A.Schiff, Eiji Hase1987 Volume 12 Issue 5 Pages 453-461
Published: 1987
Released on J-STAGE: April 18, 2008
JOURNAL FREE ACCESSCells of Euglena gracilis Klebs var. bacillaris Cori mutant W3BUL grown in darkness on Hutner's pH 3.5 medium without agitation accumulate wax ester. These cells have undeveloped proplastid remnants characteristic of this mutant. If these cells are transferred to an inorganic medium and bubbled with 2-3 % CO2 in air, the wax disappears and the proplastid expands and develops in darkness to form prolamellar bodies and membrane vessicles within 96 h. No further development takes place in darkness, but if these cultures are illuminated at 96 h formation of prothylakoids is observed. Thus the wax ester accumulated during growth can be used subsequently to support proplastid development up to the prolamellar body stage, but the formation of prothylakoids is strictly light-depend-ent. Development in this system takes place at a slower rate than in cells grown with shaking and lacking wax which are transferred to resting medium. As previously shown, all of proplastid development requires light under these conditions. It is suggested that the oxygen-requiring utilization of wax in darkness can provide energy and metabolites for a part of proplastid development but the later steps in these cells, or the entire development in cells lacking wax is supported by paramylum degradation which is strictly light-dependent. However, a specific light reaction required for prothylakoid organization is not ruled out.View full abstractDownload PDF (1401K) -
Hisao Ueyama, Kiyoshi Kurokawa, Ichiro Sasaki, Kiyoshi Ueda1987 Volume 12 Issue 5 Pages 463-470
Published: 1987
Released on J-STAGE: April 18, 2008
JOURNAL FREE ACCESSMouse sarcoma 180 cells have a polypeptide that has the same molecular weight as actin but it is more acidic than α-actin. Its tryptic peptide pattern on reversed-phase HPLC was very similar to that of β+γ-actin, an actin sample prepared by affinity chromatography on DNase I-Sepharose contained the acidic polypeptide, and monoclonal anti-actin antibody reacted with it; therefore, the polypeptide is considered an actin isoform. The mRNA for this variant actin was identified by analyzing the polypeptides translated in vitro, which indicated that the variant actin is not a post-translationally modified form of any known actin. The variant actin was not stained by polyclonal anti-gizzard actin antibody which reacts with γ-cytoplasmic, α-smooth and γ-smooth muscle actins, nor by polyclonal anti-skeletal muscle actin antibody which reacts with skeletal, cardiac and α-smooth muscle actins. These results suggest that this variant actin is related to β-cytoplasmic actin or, is a novel species whose N-terminal amino acid sequence is not Glu-Glu-Glu.View full abstractDownload PDF (738K) -
Noveen D. Das, Tohru Yoshioka, Don Samuelson, Robert J. Cohen, Hitoshi ...1987 Volume 12 Issue 5 Pages 471-481
Published: 1987
Released on J-STAGE: April 18, 2008
JOURNAL FREE ACCESSImmunocytochemical localization of phosphatidylinositol-4, 5-bisphosphate (PIP2) in the rat rod photoreceptor outer segments (OS) was investigated with rabbit antiPIP2 antibodies. The OS of the light-adapted rat eye showed little or no staining, whereas the OS of the dark-adapted eye were intensely stained for PIP2. The immunoreactivity of photoreceptor PIP2 in the eye exposed to a brief flash of light was markedly reduced. However, subsequent dark-adaptation of the flash-bleached eye resulted in a rapid recovery of PIP2 immunoreactivity; dark-adaptation for 5 min was sufficient for recovery to the fully dark-adapted level. In dark-adapted eyes exposed to graded light intensities, the PIP2 immunostaining varied with light levels and was correlated with unbleached rhodopsin concentrations. These results suggest that PIP2 in the rat photoreceptor cells is rapidly hydrolyzed upon light exposure and rapidly synthesized in the dark and that the decrease of PIP2 level is triggered by photic bleaching of rhodopsin.View full abstractDownload PDF (1295K) -
Sanae Matsumoto, Kimiko Tanaka, Akitsugu Yamamoto, Hiroshi Nakada, Mor ...1987 Volume 12 Issue 5 Pages 483-496
Published: 1987
Released on J-STAGE: April 18, 2008
JOURNAL FREE ACCESSDopamine β-hydroxylase (DBH) was purified from bovine adrenal medullae. Rabbit IgG raised against DBH inhibited its activity by 80 %. In an immunoblot analysis, the IgG specifically recognized two subunits of DBH the 72 and 75 KD components. Chromogranin A (CGA) also was purified from bovine adrenal medullae, and rabbit IgG against CGA recog-nized this chromogranin A in the immunoblot analysis. The intracellular distribution of DBH and CGA in bovine chromaffin cells was determined quantitatively by immunoelectron microscopy using post-embedding protein A-gold technique. DBH and CGA were localized exclusively on chromaffin granules. The binding of gold particles to these granules was saturable. The maximum number of gold particles bound to the granules roughly corre-sponded to the number of DBH or CGA molecules in the granules estimated biochemically. DBH was observed evenly in the periphery and in the dense matrix of the chromaffin granules.View full abstractDownload PDF (1486K) -
Toshiaki Hosokawa, Tetsuo Ueda, Yonosuke Kobatake1987 Volume 12 Issue 5 Pages 497-502
Published: 1987
Released on J-STAGE: April 18, 2008
JOURNAL FREE ACCESSUsing microcomputer image processing, we analyzed the organization of community behavior during the initiation of aggregation in densely populated Dictyostelium amoebae. Just after starvation, cells behaved randomly in both space and time. The first spatial organization was the appearance of transitory regions in which the amoebae oscillated at the same frequency but with different phase. Next, waves began to propagate con-centrically within small regions, but these domains were unstable, appearing and disappearing here and there. As time passed, waves propagated for longer distances, and eventually definite centers appeared. Spectral analysis showed that the center was characteristic in having highly ordered oscillation. Later, amoebae began aggregating at these wave propagation centers. Thus, populations of oscillating amoebae organize community behavior through competitive interaction among local oscillators, the most ordered enslaving the others.View full abstractDownload PDF (1459K) -
Munenori Noguchi1987 Volume 12 Issue 5 Pages 503-506
Published: 1987
Released on J-STAGE: April 18, 2008
JOURNAL FREE ACCESSThe ciliary movements of Triton-glycerol-extracted models of Paramecium were observed during the course of trypsin digestion. When the cilia were exposed to trypsin, ciliary reorientation took place without raising the Ca2+ concentration. Elastase, on the other hand, did not induce such a response. These results seem to suggest that the Ca2+-dependent regulating mechanism controlling the ciliary beat direction is selectively digested by trypsin.View full abstractDownload PDF (3812K)
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