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Volume 13 (1988)
- Issue 6 Pages 459-
- Issue 5 Pages 359-
- Issue 4 Pages 271-
- Issue 3 Pages 193-
- Issue 2 Pages 105-
- Issue 1 Pages 1-
Volume 13, Issue 2
Displaying 1-9 of 9 articles from this issue
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Yukiko Kunugi-Uehara, Yoshikatsu Hashimoto, Chie Ogura, Chiyoko Inagak ...1988 Volume 13 Issue 2 Pages 105-111
Published: 1988
Released on J-STAGE: April 18, 2008
JOURNAL FREE ACCESSUpon tryptic digestion of synaptosomes, ATPase activities decreased in the order of Cl--ATPase ?? Na+, K+-ATPase > anion-insensitive Mg2+-ATPase. Upon synaptosome treatment with hypotonic solution, C1--ATPase or anion-insensitive Mg2+-ATPase was slightly inactivated, while Na+, K+-ATPase underwent a much larger degree of inactivation. ATP-Mg inhibited the ATPase digestion in the hypotonic-solution-treated synaptosomes in a concentration-dependent manner, but not in the untreated synaptosomes. These results suggest that trypsin-digestible site of C1--ATPase are present on both sides of the synaptosomal plasma membrane, and the ATP-Mg binding site of the enzyme is located on the inner surface of the membrane.View full abstractDownload PDF (3642K) -
Nobuaki Furuno, Koichiro Shiokawa, Hideki Kobayashi1988 Volume 13 Issue 2 Pages 113-122
Published: 1988
Released on J-STAGE: April 18, 2008
JOURNAL FREE ACCESSThe amount of intact 40S rRNA precursor was followed by Northern hybridization in the course of the early embryogenesis of wild-type Xenopus laevis and its anucleolate mutant.
The total amount of 40S rRNA precursor did not alter appreciably until the midblastula stage, decreased at the late blastula stage, and then increased. In the anucleolate mutant, in which no rRNA synthesis occurs, the 40S rRNA precursor decreased at the late blastula stage and disappeared after the gastrula stage. In the nuclear fraction of the wild type, the 40S rRNA precursor was detectable after the midblastula stage.
Therefore, the 40S rRNA precursor in the pre-blastula embryos is maternal and decreases at the late blastula stage. New synthesis of 40S rRNA precursor apparently occurs after the midblastula stage.View full abstractDownload PDF (813K) -
Koyomi Kubota, Sumiko Katayama, Michio Matsuda, Masao Hayashi1988 Volume 13 Issue 2 Pages 123-128
Published: 1988
Released on J-STAGE: April 18, 2008
JOURNAL FREE ACCESSVitronectin is a cell-adhesive glycoprotein in serum and plasma, also termed serum spreading factor and complement S-protein. It consists of a mixture of a polypeptide of molecular weight 75 kilodalton (kDa) and its nicked product of 65 kDa plus 10 kDa. By a quantitative immunoblotting assay, human blood samples could be classified into three distinct vitronectin types; type I (58% of the population) was 75 kDa rich and 65 kDa poor, type II (35% of the population) contained approximately equal amounts of 75 kDa and 65 kDa, and type III (5% of the population) was 75 kDa poor and 65 kDa rich. The vitronectin type did not correlate with age, sex, or ABO blood type.View full abstractDownload PDF (477K) -
Reiko Sasada, Ryuji Marumoto, Koichi Igarashi1988 Volume 13 Issue 2 Pages 129-141
Published: 1988
Released on J-STAGE: April 18, 2008
JOURNAL FREE ACCESSExpression plasmids were constructed containing chemically synthesized human epidermal growth factor (EGF) gene fused in a frame to a leader sequence of human interleukin-2 (IL-2) gene under the control of a viral promoter. COS7 cells transfected with the plasmids synthesized and secreted EGF. Transfection of mouse A9 cells or BALB/3T3 clone A31 cells with the plasmids permitted the isolation of cell lines secreting the product which showed EGF activity. In particular, A31 transformed cells secreting human EGF grew well even in a medium containing a minimal level of serum. Using similar vectors having IgE cDNA (C2-C4) in place of EGF gene, a human IgE Fc fragment was also produced and secreted in mouse cells. These results show that heterologous leader sequences are useful for the expression and secretion of proteins whose genes lack leader sequences.View full abstractDownload PDF (2427K) -
Emiko Sano, Kiyoshi Okano, Ritsuko Sawada, Masanobu Naruto, Tetsuo Sud ...1988 Volume 13 Issue 2 Pages 143-159
Published: 1988
Released on J-STAGE: April 18, 2008
JOURNAL FREE ACCESSTwo expression plasmids (pSVIFNγ/BPV97 and pSVIFNγ/ AdDHFR) for constitutive production of human interferon-gamma (HuIFN-γ) were constructed and introduced into the two different mammalian cell lines, mouse C127 cells and Chinese hamster ovary (CHO) cells. Genetically engineered C127 and CHO cells grew on microcarriers having high productivity of HuIFN-γs for at least six months. Isoelectric focusing patterns and molecular weight analyses suggest that C127-and CHO-HuIFN-γs are glycopro-teins and that both HuIFN-γs have different molecular structures. The develop-ment of a microcarrier culture system for genetically engineered mammalian cells has enabled us to prepare glycosylated HuIFN-γs on a large scale.View full abstractDownload PDF (4431K) -
Kenji Arai, Takao Taki, Akiyo Kondo, Makoto Matsumoto1988 Volume 13 Issue 2 Pages 161-169
Published: 1988
Released on J-STAGE: April 18, 2008
JOURNAL FREE ACCESSThe effects of exogenously added glycosphingolipids on the differentiation of mouse myeloid leukemia cells (M1-T22) have been studied. Eight gangliosides and ten neutral glycosphingolipids were tested in terms of their induction of phagocytic activities on the leukemia cells. N-Acetyl-neuraminosyllactosylceramide (NAc-GM3) was the most effective glycolipid for inducing the activity. By the addition of 25 μg/m1 of NAc-GM3, about 70 percent of the cells acquired phagocytic activity within 20 h incubation. GMla showed about half the activity of the GM3. In the case of the neutral glycosphingolipids, lactosylceramide (CDH) and globotriaosylceramide (CTH) showed significant effects on the induction of phagocytic activity. Preincubation of the cells with the NAc-GM3 enhanced the effect of dexamethasone as a differentiation inducer on M1-T22 cells. When a human promyelocytic leukemia cell line, HL-60, was preincubated with the NAc-GM3 ganglioside, in-duction of the phagocytic activity, together with inhibition of the cell growth by phorbol ester (TPA), were markedly enhanced. From these observations, the NAc-GM3 ganglioside seems to act as a modulator of differentiation of mouse myeloid leukemia cells and also of HL-60 cells.View full abstractDownload PDF (2251K) -
Susumu Kotani, Hiromu Murofushi, Hikoichi Sakai1988 Volume 13 Issue 2 Pages 171-177
Published: 1988
Released on J-STAGE: April 18, 2008
JOURNAL FREE ACCESSMouse adrenocortical Y-1 tumor cells were examined in a monolayer culture and their steroid secretion was measured. The Y-1 cells constantly released a small amount of steroids in the absence of adrenocor-ticotropin (ACTH). When synthetic ACTH (tetracosactide acetate) was added to the medium, an increase in the steroid secretion of approximately 5-fold was observed. The Y-1 cells also showed a typical cytoplasmic retraction in response to ACTH. Incubation of the cells with an antimitotic drug, colchicine, prior to ACTH-stimulation resulted in a 30-50% reduction in ACTH-induced steroid secretion. Under the conditions used in these experiments, viable numbers of cell and of total amount of protein per dish were not measurably changed, indicating that the condition was not lethal. Another antimitotic drug, colcemid, caused similar reactions, while lumicolchicine showed no effect. This suggests that the disruption of the microtubular system is the main cause of the inhibition. On the other hand, the ACTH-independent secretion was slightly enhanced by colchicine. The enhancement was also observed in prolonged incubation with colchicine, a condition which caused death in some of the cells.View full abstractDownload PDF (680K) -
Toshiyuki Shinji, Norio Koide, Takao Tsuji1988 Volume 13 Issue 2 Pages 179-188
Published: 1988
Released on J-STAGE: April 18, 2008
JOURNAL FREE ACCESSAdult rat hapatocytes seeded in a noncoated plastic dish containing serum-free medium formed a monolayer within 24 h of culture. Those seeded in a dish coated with a proteoglycan fraction isolated from rat liver reticulin fibers attached to the dish but did not spread within 4 h, and then gradually assembled to form floating spherical aggregates (spheroids) with a diameter of 120±40 μm, within 72 h.
The proteoglycan fraction appeared to contain dermatan sulfate, heparan sulfate and an unidentified glycosaminoglycan in its glycan moieties by glycosaminoglycan analysis after pronase digestion and high molecular weight proteoglycan molecules (mw: over 300, 000 and about 200, 000) by SDS-PAGE analysis. Cells seeded in dishes coated with these defined glycosaminoglycans and heparin assembled to form hemispheroids and multilayer islands, but not floating spheroids, within 72 h of culture. Dermatan sulfate had a stronger ability to induce hemispheroids than heparan sulfate or heparin. As the hemispheroid and multilayer islands were the intermediate form between monolayer and floating spheroids, the glycosaminoglycan moieties of the proteoglycan fraction were thought to participate in the formation of spheroid.View full abstractDownload PDF (9859K) -
Yohichi Hashimoto, Kenji Matsui1988 Volume 13 Issue 2 Pages 189-191
Published: 1988
Released on J-STAGE: April 18, 2008
JOURNAL FREE ACCESSA pseudoplasmodium or slug of the cellular slime mold Dictyostelium discoideum sometimes shows positive thermotaxis or negative thermotaxis, this depending upon the relation between the temperature of amoeba growth to the late aggregation stage and the temperature of the migrating point. In this experiment, we investigated characteristics of ther-motaxis as a result of a tip exchange between positive thermotactic slugs and negative ones. Most of the tip-exchanged slugs showed negative thermotaxis. In phototaxis, it has been reported that the tip determines the migrating direction. In thermotaxis, however, this is not possible, and it is highly likely that the negatively thermotactic phenotype is dominant.View full abstractDownload PDF (278K)
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