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Volume 19 (1994)
- Issue 6 Pages 349-
- Issue 5 Pages 263-
- Issue 4 Pages 189-
- Issue 3 Pages 109-
- Issue 2 Pages 57-
- Issue 1 Pages 1-
Volume 19, Issue 3
Displaying 1-10 of 10 articles from this issue
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Taro Hayakawa1994 Volume 19 Issue 3 Pages 109-114
Published: 1994
Released on J-STAGE: March 27, 2006
JOURNAL FREE ACCESSDownload PDF (964K) -
Mayumi Sasaki, Norimasa Sawada, Hideki Chiba, Noriomi Miyao, Taiji Tsu ...1994 Volume 19 Issue 3 Pages 115-121
Published: 1994
Released on J-STAGE: March 27, 2006
JOURNAL FREE ACCESSTo investigate the relationships among vimentin, keratin and cellular polarity, reorganized glands composed of renal cell carcinoma cells were investigated in vitro. We employed two different three-dimensional collagen gel culture methods, the "floating sandwich method (FSM)" and the "dispersed embedding method (DEM)." The cells composed of reorganized glands formed by FSM culture showed distinct polarity. In contrast, the cellular polarity of the cells formed by DEM culture was less distinct. Keratin was evenly distributed throughout the cytoplasm regardless of the culture method. In contrast, in reorganized glands obtained by FSM
culture, vimentin was distinctly polarized at the basal pole while glands obtained by DEM culture showed random distribution of vimentin. These results suggest that there is a close relationship between cell polarity and intracellular localization of vimentin, and that there may be different mechanisms controlling the organization of the two intermediate filament (IF) networks.View full abstractDownload PDF (7194K) -
Hiroya Kamei1994 Volume 19 Issue 3 Pages 123-132
Published: 1994
Released on J-STAGE: March 27, 2006
JOURNAL FREE ACCESSThere have been few investigations of the cause of nuclear invagination and lobule formation. The human pancreatic cancer cells MIA PaCa-2 often show nuclear lobulation and well-developed juxtanuclear aggregates of intermediate filaments with thick bundles of intermediate filaments developed from them. Therefore MIA PaCa-2 cells were used as model cells to examine whether or not there is any relationship between the shape of the nucleus and intermediate filaments. Immunoblotting showed that the intermediate filament proteins in MIA PaCa-2 cells are vimentin, and keratins 8, 18, and 19. Fluorescence microscopy and confocal laser scanning fluorescence microscopy revealed perinuclear rings composed of intermediate filaments, that is, thick bundles of both vimentin and keratin filaments run along deep invaginations in the nucleus and, together with juxtanuclear intermediate filament aggregates, they form closed rings around nuclear invaginated and constricted sites. In other cells such as human bladder carcinoma T24 cells, human melanoma G-361 cells, and human cervix carcinoma HeLa/S3 cells, there were also thick bundles of intermediate filaments cutting into the nucleus at the nuclear invagination site. Thus, it seems that the formation of perinuclear intermediate filament rings may be involved in nuclear invagination and lobule formation in some mammalian cells.View full abstractDownload PDF (6410K) -
Keizo Takenaga, Yohko Nakamura, Shigeru Sakiyama1994 Volume 19 Issue 3 Pages 133-141
Published: 1994
Released on J-STAGE: March 27, 2006
JOURNAL FREE ACCESSTwo monoclonal antibodies (named mAb3G4 and mAb4A2) against recombinant pEL98 protein have been produced. The specificity of the mAbs was verified by immunoblot and immunoprecipitation analyses. To determine cellular localization of the pEL98 protein in NIH3T3 and 3Y1 cells, indirect immunofluorescent staining was performed using mAb4A2.The results showed that most of the pEL98 protein existed diffusely in the cytoplasm, while a part of the protein existed along actin stress fibers in both cells. The expression of pEL98 protein in various murine and human tissues and cells was also examined by immunoblot analysis using mAb3G4.The results demonstrated that the pEL98 protein was expressed in bone marrow, spleen, peritoneal macrophages and human lymphocytes, with the highest amount found in peritoneal macrophages.View full abstractDownload PDF (5417K) -
Shigehiko Yumura1994 Volume 19 Issue 3 Pages 143-151
Published: 1994
Released on J-STAGE: March 27, 2006
JOURNAL FREE ACCESSImmunofluorescence studies showed that cytoskeletons that were composed of actin and myosin II rapidly reorganized in vegetative Dictyostelium cells upon chemotactic stimulation by folic acid. The amount of F-actin increased biphasically with peaks at 5-10 sec (first peak) and 25-45 sec (second peak) after the addition of folic acid. Filaments of myosin II became associated with cell membrane with increases in the meshwork of actin filaments on the cell membrane at the time of the second peak. The number of actin foci in the actin meshwork on the cell membrane decreased transiently at the time of the second peak. The number of filaments of myosin II on the cell membrane decreased and the number of actin foci recovered concomitantly towards the end of the second peak. This reorganization of cytoskeletons during the chemotactic stimulation was also observed after the application of the calcium ionophore A23187 or cGMP to cells. These observations suggest that increases in intracellular levels of both Ca2+ ions and cGMP may play a crucial role in the rapid translocation of myosin II during stimulation by folic acid.View full abstractDownload PDF (2279K) -
M.C. Rendón, J. Bolívar, M. Ortiz, M.M. Valdivia1994 Volume 19 Issue 3 Pages 153-158
Published: 1994
Released on J-STAGE: March 27, 2006
JOURNAL FREE ACCESSA human autoimmune serum to nucleolus organizer regions (NORs) has been used to localize these structures at the light microscopic level in carp and trout tissue culture cells. In interphase cells, the immunofluorescence pattern indicates that the NORs autoantigens are contained exclusively within the nucleolus of carp epithelial (EPC) and trout gonad (RTG) cells. This fluorescence is punctuate rather than uniform, and presumably represents transcriptional complexes of ribosomal DNA. During mitosis, the autoantigens are detected by immunofluorescence microscopy at the chromosomal nucleolus organizer regions of condensed chromosomes, indicating that a considerable quantity of the molecule(s) remains bound to the ribosomal RNA genes. The major nucleolus autoantigen, denned in mammals as the upstream ribosomal binding factor (UBF), has been identified on immunoblots as a 90 kDa protein in extracts from fish cell lines and tissues. Thus, NORs appear to function as nucleation centers for ribosomal RNA together with a complex set of well-conserved protein factors, such as UBF. Our results suggest evolutionary conservation from fish to mammals with respect to ribosomal RNA biosynthesis driven by RNA polymerase I.View full abstractDownload PDF (1542K) -
Saburo Uchiyama, Shin-ichi Nagai, Keizo Maruyama1994 Volume 19 Issue 3 Pages 159-163
Published: 1994
Released on J-STAGE: March 27, 2006
JOURNAL FREE ACCESSFluorescence was observed under light microscope in living cells and cell mass of Dictyostelium mucoroides. The fluorescence was localized in the vacuoles of live vegetative cells. While the cell mass of D. discoideum does not have a stalk during migration period, the cell mass of D. mucoroides has a stalk that forms at the beginning of the migration period. We were able to observe a preferential loss of the fluorescent vacuoles from the cells of the stalk and from the stalk-forming cells at the tip region of the slug. Although the fluorescence was also present in the mature spore mass of D. mucoroides, the fluorescence was not observed in the spores, but rather in the spaces between the spores within the spore mass. The fluorescent vacuoles in the cells of vegetative stage and of migrating slug stage may be related to the interspore fluorescence in the spore mass. Possible roles of the fluorescent substance(s) in amoebae, slugs and spore masses were discussed.View full abstractDownload PDF (3312K) -
Takashi Yamamoto, Takako Ohno-Shosaku, Eri Furukawa-Uenoyama, Kazuhiro ...1994 Volume 19 Issue 3 Pages 165-172
Published: 1994
Released on J-STAGE: March 27, 2006
JOURNAL FREE ACCESSA crude protease preparation from papaya (Protease Type III, Sigma) brought about reversible adhesion between adjacent cells of a variety of species including those of lymphoid, epithelial and fibroblastic origin at low ionic strength (below 100 mM). Sensitivities of the adhesion activity to ambient ionic strength, Ca2+, Mg2+ and pH indicated that the cell-cell contact is based on the electrostatic interaction. By ion-exchanger chromatography and gel-filtration chromatography it is suggested that the adhesion molecules in the protease preparation are dimers of cationic protein of 28 kDa distinct from the proteolytic component.View full abstractDownload PDF (2098K) -
Hideki Chiba, Norimasa Sawada, Masahito Oyamada, Takashi Kojima, Kousu ...1994 Volume 19 Issue 3 Pages 173-177
Published: 1994
Released on J-STAGE: March 27, 2006
JOURNAL FREE ACCESSWe have recently shown that connexin 43 (Cx43), a major gap junction protein in osteoblasts, is expressed with an increase in cell density (CHIBA, H. et al.(1993). Cell Struc. Fund., 18 : 419-426). In the present study, we examined what kinds of hormones and cytokines regulate the gap junction protein in osteoblastic cells, using a human osteoblastic cell line (SV-HFO) after reaching a con fluent density to avoid influence of cell proliferation. Either retinoic acid (RA) or transforming growth factor-β1 (TGF-β1) induced the Cx43 expression of SV-HFO cells, as revealed by Northern blot analysis and immunocytochemistry. These modulators also increased gap junctional intercellular communication, in terms of the extent of dye transfer. On the other hand, 1α, 25-dihydroxyvitamin D3 did not influence the Cx43 expression and gap junctional intercellular communication of the cells. These results suggest that RA and TGF-β1 might maintain bone tissue as an organized tissue in vivo by increasing intercellular communication of osteoblastic cells.View full abstractDownload PDF (1917K) -
Akitsugu Yamamoto, Satoru Ozono, Minoru Onozuka, Koichiro Omori, Yutak ...1994 Volume 19 Issue 3 Pages 179-187
Published: 1994
Released on J-STAGE: March 27, 2006
JOURNAL FREE ACCESSIn the muscle spindle, one of the major sensory receptors in the vertebrate skeletal muscle, it was demonstrated that stretching caused a conductance increase of the sensory terminal membrane mainly to Na+ (Hunt, Wilkinson and Fukami, 1978 (6)). Since the muscle spindle is a slowly adapting stretch receptor, and even at rest some spindles are active, a vigorous Na, K-pump activity is expected to counteract the incessant inflow of Na+ into the terminal. To test this assumption, rat muscle spindles were examined by immunofluorescence microscopy as well as by the electron microscopic immunogold technique using antibody against rat a-subunit of Na, K-ATPase. The results indicate that the sensory ending has the highest density of the enzyme among the other cellular components examined, and that the enzyme density appears to be higher in the plasma membrane of the sensory ending facing the intrafusal muscle fiber (synaptic membrane) than the rest of the membrane (extra-synaptic membrane). The functional significance of the above findings was discussed.View full abstractDownload PDF (11719K)
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