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Volume 7 (1982)
- Issue 4 Pages 295-
- Issue 3 Pages 193-
- Issue 2 Pages 91-
- Issue 1 Pages 1-
Volume 7, Issue 2
Displaying 1-9 of 9 articles from this issue
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Nibaldo C. Inestrosa1982 Volume 7 Issue 2 Pages 91-109
Published: 1982
Released on J-STAGE: April 18, 2008
JOURNAL FREE ACCESSThe current knowledge of skeletal muscle cultures and the molecular events taking place during muscle differentiation in vitro are re-viewed. Skeletal muscle cells differentiate in a unique sequence. Mononucleated precursor cells (myoblasts), which are obtained either from embryonic muscle tissues (primary muscle cultures) or from muscle cell lines, divide exponentially in culture. After cessation of division, myoblasts start to fuse forming multi-nucleate myotubes. Subsequently, the myotubes develop myofilaments and cross-striations. In this review the concept of fusion is discussed in relationView full abstractDownload PDF (2512K) -
Haruki Hashimoto, Satoru Murakami1982 Volume 7 Issue 2 Pages 111-120
Published: 1982
Released on J-STAGE: April 18, 2008
JOURNAL FREE ACCESSLoss of chloroplast DNA and concomitant chloroplast replication were examined in Euglena gracilis Z grown photoheterotrophically in the presence of 50 μg/ml of nalidixic acid (NAL), a potent inhibitor of DNA replication. Staining with DNA-specific sensitive fluorochrome 4', 6-diamidino-2-phenylindole (DAPI) revealed that the Euglena chloroplast contains 30 or more DNA regions (nucleoids) and that NAL induced the loss of chloroplast nucleoids in a large chloroplast population within 2-3 generations after its addition. No chloroplast nucleoids were detectable in 73 % of the chloroplasts isolated from cells treated with NAL for 72 h. Although the chlorophyll content per cell markedly decreased and the chloroplast DNA was depleted, cell divi-sion and chloroplast replication were scarcely inhibited, at least within 96 h after the addition of NAL.
These results show that chloroplast replication is not affected by the inhibi-tion of replication of chloroplast DNA. They also suggest that chloroplasts are able to replicate several times after nucleoids are no longer detectable by the DAPI method.View full abstractDownload PDF (2212K) -
Shuichi Ikeyama, Yasuhiko Niiyama, Masao Takeuchi1982 Volume 7 Issue 2 Pages 121-132
Published: 1982
Released on J-STAGE: April 18, 2008
JOURNAL FREE ACCESSA clonal cell line of transformant, BHKT73, was isolated from BHK21/13 cells infected with bovine adenovirus type 3 (BAV3). BHKT73 cells showed characteristics typical of transformed cells, including the ability to grow in 1.3 % methylcellulose, high agglutinability with lectins, and unclear cytoplasmic microtubular fibers. Cot analysis showed that BHKT73 cells were contain BAV3 DNA.
Tumor-associated surface antigens (TASAs) of BHKT73 cells, and TrD-5 and TrJE-6 cells (A31 cells transformed by BAV3 DNA fragments with respec-tive map units of 3.6-19.7 and 0-11.9) were studied by the protein A binding assay with rabbit anti-BHKT73 IgG, BALB/c mice anti-BHKT73 antiserum and BALB/c mice anti-TrD-5 and TrJE-6 antisera. All these antisera bound to the surfaces of BHKT73, TrD-5 and TrJE-6 cells, but not to the surfaces of SV40-and murine sarcoma virus-transformed A31 cells. They also bound to the surface of polyomavirus-transformed cells (pyBHK and PV-4). After absorp-tion with pyBHK cells, these antisera showed decreased ability to bind to the surfaces of BHKT73, TrD-5, PV-4 and pyBHK cells. These results indicate that all the genetic information of BAV3 that is required for the expression of BAV3-TASAs is included between the map units of 3.6 and 11.9 on the BAV3 gene, and that BAV3-TASAs may have antigenic determi-nant site(s) common to one of the TASAs on polyomavirus-transformed cells.View full abstractDownload PDF (5073K) -
Mikio Kan, Isao Yamane1982 Volume 7 Issue 2 Pages 133-143
Published: 1982
Released on J-STAGE: April 18, 2008
JOURNAL FREE ACCESSWe reported previously that bovine serum albumin (BSA) has growth promoting activity which depends upon lipids (especially poly-un-saturated fatty acids) bound to the BSA molecule. This activity was proved to depend upon the oxygen tension in the culture environment. The experiment described here shows the relationship between the growth of human diploid fibroblasts in a serum-free, BSA-containing medium and changes in the sulf hy-dryl contents in the medium. When cells (2 × 104 cells/plastic petri dish) were plated in dish (diameter of 35 mm), the sulfhydryl contents of the culture media decreased rapidly, then they increased gradually. Following the increase in the sulfhydryl contents, cell growth at atmospheric oxygen tension declined. But, when the sulfhydryl contents were maintained at a low level by treating BSA with 0.0015 (W/V) % H202 or by adding sylfhydryl compounds to the medium, excellent cell growth was obtained during the period of culture. These results suggest that the number of sulf hydryl groups of albumin present may regulate the equilibrium between BSA-bound fatty acids and free fatty acids in the medium.View full abstractDownload PDF (960K) -
Haruko Kitagaki, Yumiko Hatakeyama, Isamu Matsumoto, Nobuko Seno, Mach ...1982 Volume 7 Issue 2 Pages 145-153
Published: 1982
Released on J-STAGE: April 18, 2008
JOURNAL FREE ACCESSCell surface glycoconjugate receptors for wheat germ aggluti-nin, Ricinus communis agglutinin, concanavalin A and soybean agglutinin on two strains of myxoamoebae of Physarum polycephalum with fluorescein isothiocynate-labelled lectins were observed microscopically, but no receptors for Dolichos biflorus agglutinin, Ulex europeus agglutinin-I and Arachis hypogaea agglutinin were found. These results suggest that the myxoamoebae have cell surface glycoproteins with N-glycosidically linked hetero-saccharide chains, but not oligosaccharides with blood group A and H determinants. The number of lectin receptor sites and their affinity constants for lectins were obtained for the myxoamoebae and microplasmodia of P. polycephalum from binding assays with 125I-lectins. The densities of these lectin receptors and the magni-tudes of the affinity constants were similar to those of mammalian cells. Neuraminidase treatment of the myxoamoebae and microplasmodia induced neither a decrease in WGA receptors nor an increase in RCA receptors. These results are strong evidence that sialyl residues are absent in glyco-conjugates on the surface of the myxoamoebae and microplasmodia of P. polycephalum.View full abstractDownload PDF (945K) -
Mineo Iwata, Taei Matsui, Akiya Hino, Eizo Nakano1982 Volume 7 Issue 2 Pages 155-164
Published: 1982
Released on J-STAGE: April 18, 2008
JOURNAL FREE ACCESSPolyamines induced the rapid disassembly of microtubules reconstituted from porcine brain tubulin. Of the polyamines tested, spermine was the most effective. Alkaline α-amino acids and guanidine derivatives were less effective than polyamines. β-, γ-and ε-amino acids did not induce the disassembly of microtubules.
To determine the action of polyamines, microtubule proteins were applied to a spermine-agarose affinity gel, then its eluates were identified by SDS-polyacrylamide gel electrophoresis. Tubulin and other associated proteins were eluted with 0.2 M NaCl. PC-tubulin also bound to the spermine-agarose gel. Moreover, electron microscopy showed that disk or ring structures were formed in the presence of spermine.
These results indicate that spermine binds with the tubulin molecule which induces the disassembly of reconstituted microtubules in vitro.View full abstractDownload PDF (1033K) -
Hiroyuki Tsuda, Hiroshi Maeda1982 Volume 7 Issue 2 Pages 165-175
Published: 1982
Released on J-STAGE: April 18, 2008
JOURNAL FREE ACCESSMeasurement of cellular fluidity by the fluorescence polarization method with a fluorogenic dye, fluorescein diacetate (FDA), is used widely. But values obtained with this method may be affected greatly by unknown factors. To determine the various factors that affect fluorescence polarization (FP-) measurements and intrinsic cellular fluidity, we investigated the uptake of FDA into cells, cellular esterases, fluorescein-binding protein, microtubules and osmolarity. Our results show that some reagents inhibit FDA-uptake without affecting esterases and that several types of esterases are involved in FDA-hydrolysis.
The dye-binding experiment indicated that dye-binding protein is absent from the cells. In addition, to determine whether there is involvement of microtubules in cellular fluidity, we treated cells with Ca2+ antagonists, calmodulin inhibitors and low temperature, and verified that there is little evidence for that hypothesis. In other experiments, cells were brought into a hypertonic condition, which resulted in osmolysis and higher intracellular concentrations, primarily of biopolymers, and higher viscosity. The effect of this viscosity on the FP value was investigated. Results showed a parallel relationship between osmolarity and therefore, intracellular viscosity and FP value.
In conclusion, the concentrations of intracellular proteins and other biopolymers appear to be a major factor that determines cellular fluidity, but the role of microtubules which undergo assembly-disassembly appears to be insignificant.View full abstractDownload PDF (1177K) -
II. Cytotoxicity Produced by Anticancer AgentsHiroshi Maeda, Hiroyuki Tsuda, Jiro Takeshita1982 Volume 7 Issue 2 Pages 177-182
Published: 1982
Released on J-STAGE: April 18, 2008
JOURNAL FREE ACCESSMost transformed and tumor cells rapidly take up fluorogenic fluorescein diacetate (FDA) only when they are viable, and become fluorescent because intracellular esterases generate fluorescein. When these cells were treated with the cytotoxic agents mitomycin C, neocarzinostatin, methotrexate, carboquone, cytosine arabinoside or UV-irradiation, they showed two pro-nounced changes within a short period : (a) suppression of the uptake of fluo-rescein diacetate shown by fluorescence intensity based on newly generated fluorescein and (b) change in the fluorescence polarization value (FP value), indicative of altered intracellular fluidity.
The degree of these two changes that occur shortly after drug treatment are either time or dose dependent and became apparent within one to several hours after treatment. One assay requires about 1 x 106 cells which usually generate about 2 pmol of fluorescein within 10 min at 30°C. The method is useful for rapid evaluation of cytotoxicity against tumor cells.View full abstractDownload PDF (620K) -
Tetsuo Takahashi, Yonosuke Kobatake1982 Volume 7 Issue 2 Pages 183-192
Published: 1982
Released on J-STAGE: April 18, 2008
JOURNAL FREE ACCESSA computer-linked automated system was developed for counting the number of moving microorganisms under a microscope, that discriminates whether they showed reversals or smooth swimming. The features of the system are 1) commercial I/O devices, and a microcomputer can be used to process the moving pictures, 2) fast processing is accomplished by bit opera-tions for computing the correlation matrix, and pseudo moving objects for processing on the later frames, and 3) a number of cells on the frames are processed in a short time, occluded individuals on a frame are neglected.
The system was used to study the phototactic behavior of Halobacterium halobium. High intensity background illumination caused a decrease in the sensitivity of the behavioral response of the cell to the attractant light.View full abstractDownload PDF (2714K)
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