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Volume 5 (1980)
- Issue 4 Pages 285-
- Issue 3 Pages 199-
- Issue 2 Pages 109-
- Issue 1 Pages 1-
Volume 5, Issue 2
Displaying 1-11 of 11 articles from this issue
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Hisao Ueyama, Yoko Saji, Takao Matsuura, Kiyoshi Ueda1980 Volume 5 Issue 2 Pages 109-114
Published: 1980
Released on J-STAGE: April 18, 2008
JOURNAL FREE ACCESSNuclei isolated from Tetrahymena pyriformis were subfraction-ated by treating them with micrococcal nuclease followed by successive centri-fugations. In the pellet (Lp) obtained by the first centrifugation (low speed), 80-94 % of the nuclear DNA was recovered. The pellet (Hp) and the super-natant (Hs) obtained by the second centrifugation (high speed) contained 2-10 % and 4-10 % of the nuclear DNA, respectively. The profiles of sucrose density gradient centrifugation and electrophoresis on polyacrylamide gel indicated that fraction Hs consists of mono- to oligonucleosomes. The RNA polymerase activity of fraction Hp was sensitive to α-amanitin, which suggests that the fraction contains the transcriptionally active region of chromatin. Poly(A) polymerase activity was demonstrated in all three fractions, but the specific activities (both per DNA and per protein) were high in fractions Hp and Hs.View full abstractDownload PDF (663K) -
Masahiro Suno, Kyozo Tsukamoto, Yukio Sugino1980 Volume 5 Issue 2 Pages 115-122
Published: 1980
Released on J-STAGE: April 18, 2008
JOURNAL FREE ACCESSAristeromycin, an antibiotic isolated from Streptomyces citri-color, induced DNA synthesis and cell division of non-dividing 3T3 cells (A-31) in culture. The induction occurred in quiescent cells produced by contact inhibition or by deprivation of serum or isoleucine from culture medium. In confluent culture, the maximum stimulation of DNA synthesis was observed about 24 h after the addition of aristeromycin and was followed by cell division. The optimum concentration of aristeromycin for induction was about 0.5μg/ ml on glass dishes. In contrast to its stimulative effect on nondividing cells, aristeromycin inhibited growth when added to dividing cells. Growth of other normal cell lines in confluent culture also was induced by aristeromycin. However, growth of malignant cell lines such as SV-3T3, poly-BHK, AC and KB cells was inhibited. Adenine nucleosides reversed the inductive effect of aristeromycin.View full abstractDownload PDF (879K) -
Masayoshi Namba, Fuminori Hyodo, Makoto Katayama, Masato Nakayama, Shi ...1980 Volume 5 Issue 2 Pages 123-132
Published: 1980
Released on J-STAGE: April 18, 2008
JOURNAL FREE ACCESSHuman amnion cells were cultured from amniotic fluid ob-tained by transabdominal amniocentesis of a 33-year-old pregnant woman with a fetus diagnosed as congenital osteodysplasia. The culture, which contained two morphologically distinct types of cells, epithelial and fibroblastic, was intermittently treated with the chemical carcinogens urethane and 4- nitroquinoline 1-oxide, during 7 months of the primary culture. After 6 months of culture, most cells growing in the culture were epithelial. Ultrastructurally, two types were observed, the Golgi type and the fibrillar type. Golgi type cells showed desmosomes, numerous microvilli, cytoplasmic vacuoles, and a well developed Golgi complex, indicating secretory functions. Electron dense materials were seen in the Golgi complex, cytoplasm, intracellular vacuoles, and intercellular spaces. These materials were not stained by sudan III, periodic acid Schiff, alcian blue or toluidine blue. Histochemically, lactate dehydro-genase, glucose-6-phosphate dehydrogenase, acid phosphatase and glucuroni-dase were positive in the epithelial cells, but little gamma-glutamyltranspept-idase, alkaline phosphatase, and glucosidase activity was detected. These growing epithelial cells, the proliferation of which was stimulated by treatment with chemical carcinogens, were identified by electron microscopy as epithelial cells lining the amnion.View full abstractDownload PDF (1094K) -
Takaya Sawamura, Hiroshi Nakada, Yoshiaki Fujii-Kuriyama, Yutaka Tashi ...1980 Volume 5 Issue 2 Pages 133-146
Published: 1980
Released on J-STAGE: April 18, 2008
JOURNAL FREE ACCESSA binding protein specific for asialoglycoproteins was isolated from rat liver by affinity chromatography. The protein is composed of a single glycoprotein with an estimated molecular weight of 52, 000 in which sialic acid, galactose, mannose, and glucosamine make up 10% of the total molecule. The binding activity of the rough microsomes was one third that of the smooth microsomes. Rough and smooth microsomes were digested with trypsin and neuraminidase and also incubated with the antibody to the binding protein in the absence or presence of Triton X-100. Without Triton X-100, 25-30% and 50% of the binding activity of the rough and smooth microsomes, respect-ively, were always protected from digestion by the enzymes or were freed from inhibition by the antibody. In the presence of Triton X-100, trypsin inactivated 100%, but neuraminidase inactivated 80% and 70% of the binding activity of the rough and smooth microsomes. These results suggest that the binding activity on the luminal side of the microsomal membrane is due to the precursor form(s) of the binding protein.View full abstractDownload PDF (1474K) -
Dai Ayusawa, Kimiko Iwata, Susumu Ikegami, Takeshi Seno1980 Volume 5 Issue 2 Pages 147-154
Published: 1980
Released on J-STAGE: April 18, 2008
JOURNAL FREE ACCESSThe inhibitory effects of aphidicolin on growth and DNA synthesis in vivo in mouse FM3A cells were reversed by the simultaneous addition of all four deoxyribonucleosides to the culture. In lysolecithin-permeabilized FM3A cells, the inhibition of DNA synthesis by aphidicolin also was reversed by increasing the concentrations of all four dNTP's, but not by increasing the concentrations of three of the four. DNA synthesis in per-meabilized cells exhibited a close resemblance to that in vivo with respect to its sensitivity to aphidicolin and its type of inhibition. In contrast, a 100-times higher concentration of aphidicolin was required to inhibit DNA polymerase a and its inhibition was reversed only by dCTP.View full abstractDownload PDF (857K) -
Takashi Sato, Yasunori Kanaho, Tatsuzo Fujii1980 Volume 5 Issue 2 Pages 155-163
Published: 1980
Released on J-STAGE: April 18, 2008
JOURNAL FREE ACCESSIn vitro effects of biscoclaurine alkaloids on cell morphology and the osmotic resistance of human erythrocyte membranes were examined in relationship to their incorporation into the membrane.
All the alkaloids tested induced invaginational type of transformation and a change in resistance against hypotonic hemolysis as a function of the concentration, within a range of 10-5 M to 2 × 10-4 M, in the medium. Alkaloids also were incorporated dose-dependently into cells in the same concentration range; the major part of the incorporation was in the membrane fraction. The effects of the alkaloids on the membrane as wall es their affinity for the membrane, judged by the amount incorporated, decrease as follows : tetrandrine > cepharanthine > berbamine. Fangchinoline and isotetrandrine had an invaginating effect similar to that of cepharanthine. The shape-transforming effect of cepharanthine was antagonistic to that of snake venom phospholipase A2 which induced crenation of the cells by hydrolyzing the outer layer phospholipids of the lipid bilayer of the membrane. This alkaloid did not inhibit the hydrolytic action of the enzyme on the membrane. These results indicate that the biological action of the alkaloids on the erythrocyte membrane may be due to their interaction with the lipid bilayer of the membrane.View full abstractDownload PDF (845K) -
Kazuo Ogawa, Shigeyuki Kawano, Tsuneyoshi Kuroiwa1980 Volume 5 Issue 2 Pages 165-174
Published: 1980
Released on J-STAGE: April 18, 2008
JOURNAL FREE ACCESSMitochondrial nuclei (mt-nuclei) were isolated from the microplasmodia of Physarum polycephalum in buffer containing polyamines and chelator. The individual mt-nucleus retained the native structure observed in vivo. The DNA of these mt-nuclei was the non-fragmented, native one. These characteristics indicate that the native structure is preserved during isolation. In contast to the preparation isolated with buffer exclusive of polyamines and chelator, the present mt-nuclei were stable during storage and did not aggregate. Thus, they provide useful material for the study of the morphology and biochemistry of the individual mt-nucleus.View full abstractDownload PDF (7549K) -
Akira Sono, Kengo Sakaguchi1980 Volume 5 Issue 2 Pages 175-182
Published: 1980
Released on J-STAGE: April 18, 2008
JOURNAL FREE ACCESSThe frequencies and distributions of sister chromatid exchanges and chromosomal aberrations induced by 5-fluorodeoxyuridine and ethyl methanesulfonate on cultured Chinese hamster cells were investigated. The distributions of sister chromatid exchanges and chromosomal aberrations induced by both agents in the early S phase were entirely different. Sister chromatid exchanges were distributed uniformly at a relatively higher incidence in the euchromatic regions, whereas chromosomal aberrations were more frequ-ent in heterochromatin. Combined treatment with 5-fluorodeoxyuridine and ethyl methanesulfonate significantly enhanced the frequency of sister chromatid exchanges without changing their distribution along the length of the chromosome.View full abstractDownload PDF (1835K) -
Kenji Ueda, Masatoshi Takeichi, T.S. Okada1980 Volume 5 Issue 2 Pages 183-190
Published: 1980
Released on J-STAGE: April 18, 2008
JOURNAL FREE ACCESSCellular adhesive properties of Y79 cells established from a human retinoblastoma were investigated. Y79 cells were characterized by their mutual adhesiveness in forming clusters and by the complete inability to attach to a non-cellular culture substrate. The cell-cell adhesion of Y79 cells depends on two different mechanisms. One is Ca2+-dependent and the other Ca2+- independent, as in the case of V79 cells which adhere mutually and to the culture substrate. That Y79 cells share common adhesive sites for cell-cell adhesion with V79 cells was suggested from the results of the heterotypic aggregation of these two cell types. Y79 cells attached themselves to a monolayer of V79 cells, but not to the substrate of the plastic dishes, when the medium contained serum. We concluded that the mechanisms that operate for cell-substrate adhesion differs qualitatively from the mechanisms for cell-cell adhesion.View full abstractDownload PDF (799K) -
Yoshihiro Tsutsui1980 Volume 5 Issue 2 Pages 191-194
Published: 1980
Released on J-STAGE: April 18, 2008
JOURNAL FREE ACCESSInduction of DNA synthesis in chick erythrocytes after fusion with BHK cells was compared in the early, middle and late S phase. In hetero-karyons fused with early S phase cells, more than 55 % showed the induction of DNA synthesis in the chick nuclei even in the presence of cyclo-heximide (1 μg/ml). However, in heterokaryons fused with late S phase cells, less than 20 % showed the induction of DNA synthesis in the chick nuclei in the presence of the same amount of cycloheximide. These results suggest that the induction of DNA synthesis in chick nuclei in the early S phase does not depend on protein synthesis because of the accumulation of inducers and because in the late S phase protein synthesis is necessary for the induction of DNA synthesis in chcik nuclei.View full abstractDownload PDF (452K) -
Tsuneyoshi Kuroiwa, Takahito Suzuki1980 Volume 5 Issue 2 Pages 195-197
Published: 1980
Released on J-STAGE: April 18, 2008
JOURNAL FREE ACCESSA 4'6-diamidino-2-phenyindole (DAPI) staining technique was devised to demonstrate the in situ chloroplast nuclei (ct-nuclei) in cells of higher plants. Fluorescent light microscopy of samples stained by this method revealed that most mature chloroplasts of Vicia faba contained about 15-30 small, spherical ct-nuclei.View full abstractDownload PDF (365K)
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