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Volume 4 (1979)
- Issue 4 Pages 267-
- Issue 3 Pages 169-
- Issue 2 Pages 75-
- Issue 1 Pages 1-
Volume 4, Issue 2
Displaying 1-12 of 12 articles from this issue
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Akira Sono, Kengo Sakaguchi1979 Volume 4 Issue 2 Pages 75-80
Published: 1979
Released on J-STAGE: April 18, 2008
JOURNAL FREE ACCESSDNA synthesis inhibitors enhanced and protein synthesis inhibitors reduced the frequency of sister chromatid exchanges induced by the alkylating agent, ethyl methanesulfonate in Chinese hamster cells. The synergism and antagonism mainly occured when cells were exposed to these agents during the first half of the S phase.View full abstractDownload PDF (490K) -
Hisao Miyata, Machiko Miyata, Michio Ito1979 Volume 4 Issue 2 Pages 81-89
Published: 1979
Released on J-STAGE: April 18, 2008
JOURNAL FREE ACCESSA growing asynchronous culture of the fission yeast Schizosaccharomyces pombe was induced to divide synchronously by a pulse treatment of 2, 3 or 4 h with 8 or 16 mM hydroxyurea (HU). During the pulse treatment, the rate of DNA synthesis was decreased and the cells became abnormally long. After HU removal, a synchronous burst of DNA synthesis occurred followed by synchronous nuclear division. The times for the first complete cell cycles of the HU synchronized cultures were shorter than the time of the normal cycle. These cycles in the synchronized cultures, shortened by a 2 h and by a 3 or 4 h HU-treatment, returned to normal after two and three divisions, respectively. The cycle periods and the recovery modes were dependent on the intervals of the pulse treatment, and could be described quantitatively with relation to cell size.View full abstractDownload PDF (901K) -
I-Hung Pan, Cheuh Phyllis Chang, Fu-Shih Pan1979 Volume 4 Issue 2 Pages 91-98
Published: 1979
Released on J-STAGE: April 18, 2008
JOURNAL FREE ACCESSThe Chang human conjunctival cell line was used, and a mixture of cells with various numbers of nuclei was obtained by cell fusion with Sendai virus (HVJ).
Synthesis of the RNA molecule was studied by radioautography. Statistical analysis revealed that the number of cytoplasmic grains, the number of nuclear grains, and the number of grains in all the nuclei and in the cytoplasm were all linearly related to the number of nuclei in the multinuclear cells. This relationship was found to be proportionately less than the hypothetical relationship of grain count to nuclear number in mononuclear cells with the same total number of nuclei.
Cytoplasmic transfer rates were similar in mononuclear cells and in multinuclear cells that had between 2 to 19 nuclei. The transfer rates averaged 20.54±0.46% after 1 h of incubation with [3H] 5-uridine.View full abstractDownload PDF (674K) -
Shigeyuki Kawano, Tsuneyoshi Kuroiwa1979 Volume 4 Issue 2 Pages 99-108
Published: 1979
Released on J-STAGE: April 18, 2008
JOURNAL FREE ACCESSDistribution of mitochondrial DNA (mtDNA) molecules during mitochondrial division to daughter mitochondria in the plasmodium of Physarum polycephalum has been determined by light and electron microscope autoradiographical studies. The plasmodium was incubated in a [3H]-thymidine solution during the mtDNA synthetic period (mS) to preferentially label one strand each of the mtDNA molecules. Distribution of the labeled strand on successive first and second rounds of replication and division ina nonradioactive medium was determined by quantitative light microscope autoradiographic technique. Results showed that silver grains were always distributed equally over the dividing dumbbell-shaped mitochondrion. Inaddition, the distribution frequency of the grain counts over the mitochondria followed a Poisson distribution, and the mean value decreased on mitochondrial division. We conclude that mtDNA molecules are distributed at random, but that an equal amount is divided between two daughter mitochondria. Electron microscope autoradiograms of dumbbell shaped and daughter mitochondria showed that the equal distribution of mtDNA molecules could be ascribed to an equal distribution of the mitochondrial nucleus.View full abstractDownload PDF (1089K) -
Shiro Bannai, Hoko Tsukeda, Hideo Okumura1979 Volume 4 Issue 2 Pages 109-115
Published: 1979
Released on J-STAGE: April 18, 2008
JOURNAL FREE ACCESSPreconfluent and growing human diploid fibroblasts started to die within a day in cystine-free medium. When cell growth was arrested by allowing cells to approach confluency, by the removal of serum, or by the addition of inhibitors of protein or RNA synthesis, cells could survive cystine depletion. However, when cell growth was arrested by the addition of DNA synthesis inhibitors, the cells could not survive cystine depletion. The rate of decrease in the cellular glutathione content after cystine depletion was slower under conditions where cells survived than under those where cells died. Under conditions where cells survived, a considerable amount of glutathione was retained in the cells even after two days of cystine depletion. These observations are consistent with an important role for glutathione in the survival of the human fibroblasts.View full abstractDownload PDF (599K) -
Katsushi Owaribe, Kosaku Izutsu, Sadashi Hatano1979 Volume 4 Issue 2 Pages 117-126
Published: 1979
Released on J-STAGE: April 18, 2008
JOURNAL FREE ACCESSAntibody to highly purified actin from plasmodium of Physarum polycephalum was induced in rabbits. Immunodiffusion and immunoelectrophoresis have shown that this antibody is immunologically monospecific (12). The cross-reactivity of the antibody with actins in a wide variety of eukaryotic cells and the distribution of those actins in the cells were examined by indirect immunofluorescence.
I-bands of myofibrils isolated from striated muscle of crab legs and from the mantle of squid were specifically stained by the antibody. We found that the antisera as well as normal sera contained a factor which weakly stained sea urchin sperm tails. This factor could be removed from sera by absorbing it with purified bovine brain tubulin. The acrosome of the sperm cell of a sea urchin, as well as the cytoplasmic fibers of cultured mammalian and avian cells and those of the internodal cell of Nitella, were specifically stained by the absorbed antibody. In the swarmcell of Physarum the cytoplasm was uniformly stained. Thus, the anti-Physarum actin antibody reacted with other actins in various eukaryotic cells.
Heavy meromyosin labeled with fluorescein stained the I-bands as well as the overlap regions of the A-and I-bands of myofibrils, the cytoplasmic fibers of Nitella, and the acrosome of the sperm. It also stained the tail of the aperm which was not stained with the absorbed actin antibody.View full abstractDownload PDF (1041K) -
Kazuo Watanabe, Gakuzo Tamura, Hiromi Mitsui1979 Volume 4 Issue 2 Pages 127-134
Published: 1979
Released on J-STAGE: April 18, 2008
JOURNAL FREE ACCESSThe effects of tunicamycin, a specific inhibitor of lipid-carrier dependent glycosylation of protein, on the proliferation, adhesion, and differentiation of freshly liberated chondrocytes from chick embryos were studied in clonal cell cultures. Incubation of cells with a high dose of tunicamycin (more than 30 ng/ml) caused complete inhibition of cell division. When tunicamycin was removed after a 5-day exposure in culture, cells immediately started to divide synchronously. The cloning efficiency was higher, and colony size was more regular than in the control culture. Tunicamycin interferred with the adhesion of the cells to the plastic substratum at a low dose (less than 3 ng/ml), and the number of attached cells decreased as the concentration of tunicamycin increased. However, at a higher dose (more than 30 ng/ml), all the cells adhered to the substratum. Different mechanisms of cell adhesion may operate for low and high does of tunicamycin. Formation of the cartilage matrix was not inhibited in so far as the cells proliferated to form colonies.View full abstractDownload PDF (725K) -
Yozo Iwanami, Ichiji Okada, Midori Iwamatsu, Tsukasa Iwadare1979 Volume 4 Issue 2 Pages 135-143
Published: 1979
Released on J-STAGE: April 18, 2008
JOURNAL FREE ACCESSRoyal jelly acid and sebacic acid contained in the royal jelly and myrmicacin in the secretions of the ant strongly affected the germination, pollen tube elongation and mitotic division of the generative nucleus of pollen grains under an acidic condition (pH 5.0). 2-Decenoic acid and capric acid had much stronger inhibiting activities on pollen growth than did the insect-origin acids. The secretions of the ant and the honeybee containing the inhibitors are believed to serve to prevent putrefaction or to inhibit growth of collected foods. The compounds can be used both as antiseptics and as inhibitors for biological researches.View full abstractDownload PDF (801K) -
Ichiro Yahara, Fumiko Kakimoto-Sameshima1979 Volume 4 Issue 2 Pages 143-152
Published: 1979
Released on J-STAGE: April 18, 2008
JOURNAL FREE ACCESSSurface architecture of lymphocytes undergoing ligandindependent (LI-) cap formation in hypertonic medium was studied by scanning electron microscopy (SEM). When lymphocytes were incubated in hypertonic medium, surface microvilli* on the cell surface were first replaced by lamellae* prior to the translocation of these structures. Microvilli were accumulated in the region of the cap as surface receptors moved to form a cap in one pole of the cell. The surface of cells with a cap and accumulated microvilli was covered with lamellae until LI-cap formation was fully induced. Cells with accumulated microvilli at one pole and with smooth surface on the residual cell body appeared subsequently after incubation in a hypertonic medium for 15 min or longer. The shape of the stumps of projections on the cell surface of lymphocytes was examined by freeze-fracture methods, which verified the observations made by SEM.
These results led to the hypothesis that the accumulation of microvilli at one pole of the cell during LI-cap formation occurs by transformation of microvilli into lamellae, the translocation of this latter structure to one pole and the reverse transformation of lamellae into microvilli.
Since both microvilli and lamellae are known to be composed of microfilamentous structures, redistribution of these structures that accompany LI-cap formation are probably associated with the redistribution of actin, the main structural protein of the microfilaments. This was shown to be the case by indirect immunofluorescence methods using actin antibody.View full abstractDownload PDF (5806K) -
Yasuhiko Tsunematsu, Masanori Iwadare, Wakako Endo, Kiyoaki Kamijo1979 Volume 4 Issue 2 Pages 153-156
Published: 1979
Released on J-STAGE: April 18, 2008
JOURNAL FREE ACCESSAn epithelial cell line (RLC1005) derived from normal fetal rat liver has been established. The cells are polygons and show intimate cell to cell adhesion. Electron microscopy showed that they are similar to hepatocytes, because of the presence of glycogen granules and of smooth surface ER, and the presence of intercellular structures similar to the bile canaliculi found in situ.View full abstractDownload PDF (6389K) -
Noburo Kamiya, Kyoko Kuroda1979 Volume 4 Issue 2 Pages 157-161
Published: 1979
Released on J-STAGE: April 18, 2008
JOURNAL FREE ACCESSA new type of pneumatically controlled cell compressor is described. Compression without shear play was possible by the slight inward bending of a pair of coverslips which was caused by negative air pressure applied to the interior of the chamber.View full abstractDownload PDF (2296K) -
Hiroshi Mori, Masanori Kurokawa1979 Volume 4 Issue 2 Pages 163-167
Published: 1979
Released on J-STAGE: April 18, 2008
JOURNAL FREE ACCESSNeurofilaments consisting almost exclusively of triplet polypeptides (with molecular weights of 200, 000, 160, 000 and 68, 000) were isolated from the rat peripheral nerve. A portion of the triplet polypeptides seems to exist in a non-polymeric form that is not sedimentable by high-speed centrifugation, and is undetectable by electron microscopy. In the presence of both neurofilaments and vinblastine sulphate, a white precipitate developed at 37°C, that rapidly redissolved at 4°C. Electron microscopy showed that the appearance of the neurofilaments did not alter during their interaction with vinblastine.View full abstractDownload PDF (5691K)
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