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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 3
Displaying 1-12 of 12 articles from this issue
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Seiji Sato, Yoshito Kinoshita, Takuji Takeuchi1980 Volume 5 Issue 3 Pages 199-208
Published: 1980
Released on J-STAGE: April 18, 2008
JOURNAL FREE ACCESSSome tyrosinase-negative variants which lost detectable tyrosinase activity were isolated from cultured tyrosinase-positive B16 mouse melanoma cells. These were compared with the tyrosinase-positive cell lines with regard to their ability to differentiate and their transformed phenotypes.
None of the tyrosinase-negative variants isolated possessed melanosomes. Attempts to find a tyrosinase inhibitor in the sodium desoxycholate cell lysate of these tyrosinase-negative variants and to induce tyrosinase activity by theophylline treatment were unsuccessful. The tyrosinase-negative variants were exclusively flat and like fibroblasts, whereas the tyrosinase-positive cell lines were rounded and spindle-shaped. Moreover, the tyrosinase-negative variants showed less ability to form colonies in soft agar and greater adhesive-ness to the substratum as compared to the tyrosinase-positive cell lines.
Our results indicate a positive correlation between melanogenic ability and the expression of transformed phenotypes in the constitutively tyrosinase-positive and tyrosinase-negative melanoma cell lines.View full abstractDownload PDF (1097K) -
Tamotsu Yoshioka, Kaoru Sekiba, Kozo Utsumi1980 Volume 5 Issue 3 Pages 209-213
Published: 1980
Released on J-STAGE: April 18, 2008
JOURNAL FREE ACCESSIn an attempt to determine the developmental mechanism of neonatal jaundice and its prevention, we investigated the fragility of erythro-cytes in umbilical cord blood and maternal blood by observing the release of potassium from them at a high concentration of bilirubin.
Results showed that the amount potassium released from the erythrocytes increased in the presence of bilirubin and was more marked in erythrocytes from the umbilical cord than in those of maternal blood. An addition of cepha-ranthine to the erythrocyte suspension inhibited potassium release.
Our data suggest that cepharanthine might be used as an antihemolitic drug against neonatal jaundice.View full abstractDownload PDF (408K) -
Dai Duy Ban1980 Volume 5 Issue 3 Pages 215-221
Published: 1980
Released on J-STAGE: April 18, 2008
JOURNAL FREE ACCESSThe activity of adenosine triphosphatases in L1210 lymphoid leukemic cells was demonstrated by ultracytochemical methods. The activity of Na+, K+-ATPase was found only in the plasma membrane, but the activity of Mg2+-ATPase and Ca2+-ATPase was found in both the plasma membrane and in the membrane surrounding lipid vacuoles in the cytoplasm. The activity of Ca2+-ATPase predominated on the periphery of the lipid vacuoles. The localization of these enzymes is discussed in reference to its possible significance in transformed cells.View full abstractDownload PDF (818K) -
Ichiro Yahara, Fumiko Kakimoto-Sameshima1980 Volume 5 Issue 3 Pages 223-232
Published: 1980
Released on J-STAGE: April 18, 2008
JOURNAL FREE ACCESSThe number and distribution of intramembrane particles (IMPs) were examined on capped lymphocytes and control cells. Simultaneous movement of surface receptors and microvilli during ligand-independent (LI-) cap formation in a hypertonic medium made it possible not only to dis-tinguish between capped and non-capped cells in freeze-fractured specimens but also to detect the region where receptors had accumulated by referring only to their morphology. No accumulation of IMPs in the region of the cap was detected, and the distribution of IMPs was random for both capped and non-capped cells. However, the density of IMPs on the protoplasmic halves of cleaved membranes was slightly, but significantly, lower for capped cells than for non-capped cells, whereas that on the exoplasmic halves did not differ. These results suggest that the majority of IMPs are not composed of mobile receptors such as surface Ig, and surface receptors found as IMPs before cap formation might be changed by this event in the intercalated state into the lipid bilayer and, thus might not be detected as IMPs on cap forming cells.View full abstractDownload PDF (1209K) -
Hideaki Maekawa, Hiroshi Doira, Bungo Sakaguchi1980 Volume 5 Issue 3 Pages 233-238
Published: 1980
Released on J-STAGE: April 18, 2008
JOURNAL FREE ACCESSThe proportions of fibroin mRNA synthesized in the posterior silk gland of the flimsy cocoon mutant (flc) of Bombyx mori at days 3, 4 and 5 of the fifth instar were 1.2 %, 0.7 % and 1.8 % of the labeled total RNA, re-spectively, whereas those in heterozygous larva (+/flc) at the same stages were 1.6 %, 3.2 % and 8.5 %, respectively. The total amount of fibroin mRNA that accumulated in one larva at day 5 of flc was less than 10 μg and that of +/flc was about 110 μg. The intracellular distribution of the mRNA also was measured. The proportion in the nuclear fraction was 0.5 % of the total labeled RNA for flc and 0.8 % of that for +/flc; in the cytoplasmic fraction the pro-portion was 0.2 % for flc and 2.4 % for +/flc. Thus, the reduced amount of fibroin mRNA in the flc mutant is considered to be due to the degradation of the synthesized mRNA rather than to a reduction in the synthesis of mRNA. It is believed that this degradation causes abnormal fibroin production. The primary action site of the flc gene is not known.View full abstractDownload PDF (579K) -
Etsuya Matsutani, Yukiaki Kuroda1980 Volume 5 Issue 3 Pages 239-246
Published: 1980
Released on J-STAGE: April 18, 2008
JOURNAL FREE ACCESSMesenchyme cells dissociated from the limb buds of quail embryos (stages 21-22) were used to study the effects of different types of cell association for various periods on cartilage differentiation. The mesenchyme cells were first incubated for 4-48 h as monolayers, precipitated pellets, or cultures with gyratory shaking or reciprocal shaking. The cells then were dissociated, and their ability to form cartilage colonies in cultures at low cell density was examined. Cells that had been incubated as monolayers or in cultures with reciprocal shaking formed only fibroblastic colonies, whereas cells that had been incubated in cultures with gyratory shaking for 12 h or as pellets for 16 h formed cartilage colonies. With the last two treatments, the number of cartilage colonies increased according to the prior incubation period. Thus, three-dimensional cell association for a certain period may stabi-lize the ability of mesenchyme cells to differentiate into cartilage cells.View full abstractDownload PDF (872K) -
Isao Adachi, Takuya Katagiri, Tadao Terao, Toshiaki Osawa1980 Volume 5 Issue 3 Pages 247-257
Published: 1980
Released on J-STAGE: April 18, 2008
JOURNAL FREE ACCESSThe transmembrane organization of concanavalin A receptor proteins in purified plasma membranes from guinea pig peritoneal exudate macrophages was investigated. Inside-out vesicles prepared from the plasma membrane by affinity chro-matography on concanavalin A-Sepharose remained permeable to con-canavalin A and could be labelled from the outside only with immobilized lactoperoxidase-catalysed radio-iodination. After detergent solubliization, concanavalin A receptor proteins were isolated from the radio-iodinated inside-out vesicles and their mobilities were analyzed by electrophoresis in poly-acrylamide gels containing sodium dodecyl sulfate; this was followed by autoradiography. By these procedures, four iodinated proteins with apparent molecular weights of approximately 147, 000, 125, 000, 102, 000 and 77, 000 were specifically retained in the concanavalin A-Sepharose affinity columns, evidence that these glycoproteins span the plasma membrane.View full abstractDownload PDF (1167K) -
Maria Ori, Yoshiki Shiba, Yoshinobu Kanno1980 Volume 5 Issue 3 Pages 259-263
Published: 1980
Released on J-STAGE: April 18, 2008
JOURNAL FREE ACCESSMouse macrophages cultured in vitro for 2 days were coupled to each other electrically. An increase in the concentration of external calcium ion from 0.5 mM to 4.0 mM caused the increased occurrence of coupled cells immediately after replacement. This increase in coupling was inhibited in the presence of 5.3 × 10-6 M Verapamil, 0.1 mM LaCl3, 2.0 mM MnCl2 and 10-11 M colchicine. An increase in the Mg concentration from 0.1 mM to 4.0 mM and in the Ca concentration from 0.5 mM to 10.0 mM did not increase coupling. These results suggest that mouse macrophages are capable of establishing cell coupling with each other in vitro and that calcium ion acts on the cell surface and facilitates the formation of coupling.View full abstractDownload PDF (477K) -
Hoyoku Nishino, Atsuko Nishino, Katsutoshi Fujita, Teiko Hasegawa, Aki ...1980 Volume 5 Issue 3 Pages 265-268
Published: 1980
Released on J-STAGE: April 18, 2008
JOURNAL FREE ACCESSPhorbol 12-myristate 13-acetate a highly active tumor-promoting agent accelerates the uptake of α-aminoisobutyric acid (AIB)** in mouse fibroblasts. The increase in AIB uptake was caused by changes in the plasma membrane and was accompanied by a decrease in the Km value for AIB and an increase in Vmax. The increase in nutrient uptake may be an essestial factor in the induction and maintenance of the malignant phenotype of these cells.View full abstractDownload PDF (387K) -
Masao Hyodo, Kenshi Suzuki1980 Volume 5 Issue 3 Pages 269-274
Published: 1980
Released on J-STAGE: April 18, 2008
JOURNAL FREE ACCESSRapid decay of DNA replicating activity was observed when cells were incubated initially for a brief period in isotonic sucrose solution with 2-mercaptoethanol before the assay of [3H]TTP incorporation. This rapid decay was prevented when ATP was added or when 2-mercaptoethanol was omitted from the solution during the incubation. Furthermore, 2-mercapto-ethanol inhibited the incorporation of [3H]TTP into the DNA of the per-meabilized cells although the initial rate of incorporation of [3H]TTP was the same as for the control. Since DNA polymerase activity was not inhibited by 2-mercaptoethanol, our results suggest that the DNA replication complex in mouse cells contains some unknown factors that are destabilized by 2-mer-captoethanol, but the activity of the complex is protected by ATP.View full abstractDownload PDF (554K) -
Toshimitsu Okeda, Ryosaburo Takaki, Junko Ono, Yohichi Yasunami1980 Volume 5 Issue 3 Pages 275-280
Published: 1980
Released on J-STAGE: April 18, 2008
JOURNAL FREE ACCESSBoth fetal and adult human pancreatic tissues were digested with collagenase, and the resulting cell clumps, including isolated islets, were cultured with Dulbecco's modified Eagle medium (D-MEM) containing 10 fetal bovine serum (FBS) in a CO2 incubator gassed with 5 % CO2 in air. Cells became attached to the bottoms of the petri dishes and formed cell sheets after 3 days. Most epithelial cells in the monolayer were positively stained with aldehyde fuchsin and were maintained for about 2 weeks.
Insulin release in the fetal culture on the 3rd day was 1.3 times for 3 mg/ml glucose, 3.5 times for 150 μg/m1 tolbutamide and 7.8 times for 10 mM theo-phylline, as compared to that of 1 mg/ml glucose. However, in the adult cul-ture, the stimulus of glucose, tolbutamide and theophylline resulted in equal increases in insulin release of about 5 to 6 times. These results indicate that the cell function, characteristic of fetal and adult human islets in vivo, is preserved in culture.
In the fetal culture, the insulin response to glucose tended to increase on the 14th day, whereas the response to theophylline and tolbutamide decreased, evidence of the possible development of a B cell function in the culture.View full abstractDownload PDF (557K) -
Tatsumi Hirose, Tetsuo Ueda, Yonosuke Kobatake1980 Volume 5 Issue 3 Pages 281-284
Published: 1980
Released on J-STAGE: April 18, 2008
JOURNAL FREE ACCESSAn optical method was designed for monitoring contractile activities in the plasmodia of Physarum polycephalum when the plasmodia were migrating and just before the formation of sporangia and spherules. A plas-modium at each stage was mounted under an optical microscope so that it could be viewed as a whole organism. The light at the ocular was partially obstructed by the non-transparent plasmodium, reflecting its deformation. The application of attractants (glucose, maltose, phenylalanine) and repellents (KC1, CaC12, LaC13) caused relaxation and contraction of the normal plasmo-dium. Until just before sporulation and sclerotization the contraction rhythm persisted synchronously, whereas the amplitude of the oscillation gradually diminished. The oscillation period remained at a constant level during fruiting, but was prolonged during sclerotization.View full abstractDownload PDF (355K)
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