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Volume 4 (1979)
- Issue 4 Pages 267-
- Issue 3 Pages 169-
- Issue 2 Pages 75-
- Issue 1 Pages 1-
Volume 4, Issue 1
Displaying 1-9 of 9 articles from this issue
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Junzo Sasaki, Shigeto Kanda, Nagayasu Otsuka, Shu Nakamoto, Masaharu M ...1979 Volume 4 Issue 1 Pages 1-10
Published: 1979
Released on J-STAGE: April 18, 2008
JOURNAL FREE ACCESSThe redistribution of Concanavalin A (Con A) receptor sites on Ehrlich ascites tumor cells was studied by fluorescence and electron microscopy. The fluorochrome of fluorescein isothiocyanate (FITC)-Con A was distributed diffusely on the cell surface (as a ring) at 0°C, whereas it was concentrated at one pole of the cell (cap formation or capping) at 37°C. Cap formation occurred within 10 min when FITC-Con A was added to cells at 37°C or when cells, preincubated with FITC-Con A at 0°C, were warmed at 37°CC. Binding of FITC-Con A to cells was inhibited by the addition of 50 mM a-methyl glucoside. Upon incubating the cells with FITC-Con A for 2 h, concentrated fluorochrome appeared to be endocytosed at the cap region and much fluorescence in granular form remained at this locus in the cytoplasm even after the addition of α-methyl glucoside. This process was completely inhibited with 5 mM sodium azide.
Under the electron microscope, control cells showed a diffuse and random distribution of microvilli and Con A receptors on their surfaces. In contrast, a large bundle of microvilli with bound Con A at the base of each microvillus was observed at one pole of the Con A-treated cells, indicating the gathering of Con A receptors corresponding to cap formation.
The significance of cap formation is discussed in relation to the phagocytotic mechanism based on results of the present study.View full abstractDownload PDF (987K) -
Shoji Okamura1979 Volume 4 Issue 1 Pages 11-22
Published: 1979
Released on J-STAGE: April 18, 2008
JOURNAL FREE ACCESSColchicine at the concentration of 10-4 M completely inhibited phragmoplast formation of culcured carrot cells and produced large spherical cells, whereas griseofulvin and caffeine produced large but irregular cells. In the presence of griseofulvin or a lower concentration of colchicine (10-5 M), septum formation was incomplete and highly irregular cross walls were formed. Caffeine also inhibited normal septum formation, but it did not induce intricate cross walls.
Inhibition of cytokinesis by 10-4 M colchicine could be the result of the loss of cytoplasmic microtubules in the phragmoplast region. In cells treated with 10-5 M colchicine or 5 × 10-5-10-3 M griseofulvin, a considerable number of microtubules remained but the array of vesicles in the phragmoplast region was markedly disordered. Caffeine seemed to inhibit fusion of the vesicles aligned in the phragmoplast region.View full abstractDownload PDF (9851K) -
Yoshinobu Shigenaka, Tadashi Maruoka, Akira Toyohara, Toshi-nobu Suzak ...1979 Volume 4 Issue 1 Pages 23-34
Published: 1979
Released on J-STAGE: April 18, 2008
JOURNAL FREE ACCESSThe influence of sulfhydryl-blocking reagents, p-chloromer-curibenzoate (PCMB) and N, N-dimethylamide (diamide), on heliozoan axopodia was examined with particular emphasis on the degradation and reformation mechanism of the axopodia. Diamide had less effect on axopodial degradation at concentrations up to 10-3 M. In contrast, PCMB (10-4 to 10-5 M) rapidly induced almost complete degradation of axopodial microtubules. Lower concentrations of PCMB (10-6 to 10-7 M) caused partial degradation of the axopodia; thus, the degradation effect of PCMB was highly concentration-dependent. 10-3 M diamide inhibited axopodial recovery from partial degradation by 10-5 M PCMB although PCMB did not disturb the recovery process even at the concentration that induced partial degradation of the axo-podia. Some control mechanisms that determine axopodial length and the disand re-assembly of microtubules in vivo are discussed.View full abstractDownload PDF (8661K) -
Hideki Toyotama, Yasuo Nakaoka1979 Volume 4 Issue 1 Pages 35-43
Published: 1979
Released on J-STAGE: April 18, 2008
JOURNAL FREE ACCESSThe effect of temperature on the swimming velocity of Triton-extracted models of a paramecium was compared to the effect on native para-mecium. The swimming velocity of the extracted models in the reactivating medium containing Mg-ATP increased as the temperature rose to the culture temperature, then decreased at higher temperatures. The maximum was at the culture temperature. When the temperature was suddenly dropped or raised, the swimming velocity of the models showed a transient increase that decreased to a stationary value within 2 min. In all the conditions examined, the change in the swimming velocity paralleled the change in the beat frequency of cilia. Thus, the motile system of the paramecium after detergent treatment retains the influence of the culture temperature, and it can show a dynamic response to temperature change.View full abstractDownload PDF (784K) -
Setsuro Mizukami, Noriyuki Satoh1979 Volume 4 Issue 1 Pages 45-49
Published: 1979
Released on J-STAGE: April 18, 2008
JOURNAL FREE ACCESSWhen isolated embryonic cells of the medaka, Oryzias latipes, were brought into physical contact within 30 sec of dissociation, cell fusion could be induced, but fusion could no longer be induced between cells that had been isolated for more than 90 sec. Observations with a scanning electron microscope revealed that the cell surface was smooth immediately after dissociation. Cells examined about 30 sec after dissociation, however, had a great wealth of surface folds. The cell surface observed about 90 sec after dissociation was again smooth. Fusing cells were highly plicated. At the contact sites of the two fusing cells many plicae were intertwined in complex patterns. The transitory existence of cell surface folds is believed to be a prerequisite for this cell fusion.View full abstractDownload PDF (504K) -
Tsuneyoshi Kuroiwa, Shigeyuki Kawano1979 Volume 4 Issue 1 Pages 51-62
Published: 1979
Released on J-STAGE: April 18, 2008
JOURNAL FREE ACCESSThe spatial relationship between the mitochondrial nucleus (mt-nucleus) containing a large amount of DNA (mtDNA) and the mitochondrial limiting membrane in Physarum polycephalum was investigated. After labeling the mtDNA with [3H]-thymidine, significant labels appeared over the space of the mitochondrial matrix as well as the mt-nucleus; this suggests that an appreciable amount of the mtDNA exists in the matrix. When the cristae and inner limiting membrane are removed selectively by Triton X-100 lysis, DNA-like fibers appear to extend from the mt-nucleus to the matrix space. One end of these fibers is attached to a knob-like structure that adheres to the outer limiting membrane of the mitochondrion. A portion of the mtDNA in the isolated mt-nucleus also extends from the mt-nucleus and is associated with mitochondrial membrane-like patches through the knob-like coupling. These results suggest that the mtDNA extends from the mt-nucleus throughout the mitochondrial matrix and that it is associated with the mitochondrial limiting membrane complex in the mitochondrion in situ.View full abstractDownload PDF (1574K) -
Chikafusa Fukazawa, Kyoko Udaka, Kensuke Shimura1979 Volume 4 Issue 1 Pages 63-66
Published: 1979
Released on J-STAGE: April 18, 2008
JOURNAL FREE ACCESSAntisera against silkgland whole histone was species and organ specific in Hl histone derived from two regions of the silkgland and the calf thymus gland. Little or no cross-reaction was observed between the antisera and calf thymus H1 histone as judged by the quantitative microcomplement fixation reaction. These remarkable antigenic differences in the H1 Histone of the silkgland and the calf thymus gland may mean that a great phylogenic divergency exists in this histone class.View full abstractDownload PDF (2130K) -
Yozo Iwanami, Eigoro Tazawa, Tsukasa Iwadare1979 Volume 4 Issue 1 Pages 67-70
Published: 1979
Released on J-STAGE: April 18, 2008
JOURNAL FREE ACCESSCarboxylic acids containing 7 carbons or more such as enan-thic, caprylic, pelargonic and β-hydroxydecanoic acids inhibited cleavage of Hemicentrotus pulcherrimus eggs at a concentration of 200 ppm. Decan-3-o 1, in which the carboxyl group is replaced with the methyl group, had no in-hibiting effect. β-hydroxydecanoic acid (myrmicacin) had a strong inhibiting effect that was almost completely reversed by transfer of the eggs to a medium lacking the acid after a limited period of exposure.View full abstractDownload PDF (384K) -
Sachiko Endo1979 Volume 4 Issue 1 Pages 71-74
Published: 1979
Released on J-STAGE: April 18, 2008
JOURNAL FREE ACCESSThe region around the centriole of the sea urchin egg was ob served with electron microscopy at prophase, metaphase and anaphase. Many electron-dense clusters surrounded the centriole from prophase throughanaphase. They consisted of granules with diameters from 60 to 100 nm. Microtubules of asters and spindle were focused on these clusters.View full abstractDownload PDF (3882K)
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