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Volume 9, Issue 1
Displaying 1-10 of 10 articles from this issue
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Masasuke Araki, Kenji Watanabe, Kunio Yasuda1984 Volume 9 Issue 1 Pages 1-12
Published: 1984
Released on J-STAGE: April 18, 2008
JOURNAL FREE ACCESSPhotoreceptor cells in chick retina consist of a rod and five types of cones. Immunocytochemical techniques have pinpointed rhodopsin-like immunoreactivity in the outer segments of some single cones as well as in rods. The antibody used in our study was raised against bovine rhodopsin purified by SDS-polyacrylamide gel electrophoresis. No rhodopsin-like immunoreactivity was found in the principal and accessory cone. Epon-embedded, semi-thin sections also were treated with potassium hydroxide to remove epoxy resin and then subjected to immunoreaction with the antibody. With this method the same results were obtained repeatedly, and the possibility of staining failure in double cones and some single cones due to insufficient permeability was avoided.
Electron microscopy revealed that the oil droplets of stained single cones are slightly smaller and are located in a more vitreal position than those of unstained single cones. The stained single cones are presumed to be types II and III single cones. In the inner segment, especially in the Golgi region and the rER, no staining was seen. Only slight staining was found in the connecting cilium and in the small vesicular or granular structure between the oil droplet and the plasma membrane facing the heavily stained outer segment. This suggests that opsin is incorporated into the plasma membrane in the distal portion of the inner segment.View full abstractDownload PDF (1264K) -
Masanori Murakoshi, Yoshiyuki Osamura, Keiichi Watanabe1984 Volume 9 Issue 1 Pages 13-23
Published: 1984
Released on J-STAGE: April 18, 2008
JOURNAL FREE ACCESSThe relation between adrenal cholesterol synthesis and ultrastructural changes was studied in rat adrenal glands stimulated by 4-amino-pyrazolopyrimidine (4-APP). Ultrastructural observations were focused on the inner fasciculata-reticularis (Zone I) and the outer fasciculata (Zone O) of the adrenal glands. Zone I in 4-APP-treated rat adrenals had increased tubules and vesicles in the smooth endoplasmic reticulum, mitochondrial enlargement and the accumulated osmiophilic lipid droplets. In contrast, Zone O of the 4-APP-treated rat adrenals showed a decrease in osmiophilic lipid droplets and no increase in any of the elements of the smooth endoplasmic reticulum.
These results are strong evidence that under 4-APP treatment cholesterol synthesis takes place in the increased smooth endoplasmic reticulum in Zone I cells. The functional status of the cells of the inner and outer zones of the adrenal cortex also is discussed.View full abstractDownload PDF (1394K) -
Akira Masuda, Goro Eguchi1984 Volume 9 Issue 1 Pages 25-35
Published: 1984
Released on J-STAGE: April 18, 2008
JOURNAL FREE ACCESSPTU markedly enhanced the cytotoxic effects of CuCl2 on chick embryonic PECs cultured in vitro. We investigated this newly discovered effect of PTU and its analogues in relation to the toxic effects of Cu ion. Most PECs maintained in medium containing 0.5 mM PTU were lysed within 4 h by the addition of 0.1 mM CuCl2, which addition killed no PECs in the absence of PTU. The effect of PTU was not specific to PECs. All the cell lines tested, KB, N-18, N-115 and B-16, reacted against exogenous Cu in the presence of PTU as did the PECs.
Analogues of PTU had effects on PECs similar to those on PTU in the pre-sence of Cu ion. ANTU had a greater effect than PTU. MTU and TU had less effect than PTU. PTU did not affect the cytolysis induced by the addition of the divalent cations Mn, Co and Zn. About 6-fold the 64Cu-uptake by PECs was scored in the presence of PTU. The relation between this cytotoxic-enhancing effect and other biological activities of PTU are discussed.View full abstractDownload PDF (1241K) -
Hajime Satoh, Tetsuo Ueda, Yonosuke Kobatake1984 Volume 9 Issue 1 Pages 37-44
Published: 1984
Released on J-STAGE: April 18, 2008
JOURNAL FREE ACCESSThe plasmodium of the myxomycete Physarum polycephalum shows rhythmic contraction. The effect of mitochondrial inhibitors on this activity was examined. The separate inhibition of respiration or of H-F--ATPase activity or of ATP/ADP translocation failed to stop rhythmic contraction although the period of oscillation was affected. The concurrent inhibition of respiration and ATPase activity or the concurrent inhibition of respiration and ATP/ADP translocation, however, almost wholly suppressed contraction. Removal of respiratory inhibition in either case restored rhythmic contraction. The resumption of rhythmic activity occurred even though the ATP concentra-tion in the plasmodium remained at half the control level. Our results suggest that a particular mitochondrial state is indispensable for rhythmic contraction in Physarum polycephalum, and that this state influences rhythmic activities by means other than the control of the ATP level.View full abstractDownload PDF (703K) -
T. Choku Takahashi, Hidemi Sato1984 Volume 9 Issue 1 Pages 45-52
Published: 1984
Released on J-STAGE: April 18, 2008
JOURNAL FREE ACCESSThe effect of D2O on the crystallization of polymerizable tubulin in sea urchin egg cytoplasm was investigated by estimating the yield of "vinblastine (VB)-crystals" by directly measuring the dimensions of the crys-tals produced and by protein assays of the crystal isolates.
The yield of VB-crystals in mature unfertilized eggs was fairly constant; it neither increased nor decreased in the presence of D2O. On fertilization, the yield of crystals decreased markedly as compared with yields from unfertilized eggs; but, the yield was restored to the value for unfertilized eggs when an adequate concentration of D2O was present during incubation.
These results are evidence that tubulin molecules in unfertilized sea urchin eggs are in the polymerizable state but become masked and partly unpolymeriz-able after fertilization and that D2O releases the masked state and converts unpolymerizable tubulin molecules into active and polymerizable state.View full abstractDownload PDF (753K) -
Masaki Masaki, Shiro Matsuura, Yutaka Tashiro1984 Volume 9 Issue 1 Pages 53-66
Published: 1984
Released on J-STAGE: April 18, 2008
JOURNAL FREE ACCESSChanges in rat livers after treatment with phenobarbital (PB), β-naphtoflavone (βNF) or 3-methylcholanthrene (MC) was stopped were investigated by biochemical, immunochemical and electron microscopic methods. Repeated injections of each drug led to increases in the relative liver weights, in the microsomal proteins per gram of liver, in the microsomal contents of the total cytochrome P-450, and in the corresponding molecular species of P-450; P-450(PB), when treated with PB and P-450(MC) when treated with either βNF or MC. After cessation of treatment with PB or βNF, decreases in all these contents to what were essentially the control values took place approximately in parallel within 7 days. The apparent half lives of cyto-chrome P-450(PB) and P-450(MC) were calculated from the regression lines of cytochrome P-450 as approximately 15 hours. After treatment with MC, however, all the increases were maintained at approximately the maximal values even after 9 days.
Electron microscopy revealed that the smooth ER, which markedly proli-ferated on PB or βNF treatment, decreased rapidly after the drug treatment stopped, and was accompanied by an increase in the number of autophagosom-es. After treatment with MC, however, the proliferated smooth ER remained even after 9 days.View full abstractDownload PDF (10217K) -
Kazuko Tsuneoka, Mikio Shikita1984 Volume 9 Issue 1 Pages 67-81
Published: 1984
Released on J-STAGE: April 18, 2008
JOURNAL FREE ACCESSA granulocyte colony-stimulating factor (G-CSF) was highly purified from the serum-free culture medium of RSP-2•P3 cells. The G-CSF had an apparent molecular weight of 33, 000 as determined by high speed gel permeation chromatography, but its molecular weight was decreased to 15, 000 by 0.1 % sodium dodecyl sulfate. A small amount of monocyte/macrophage CSF (M-CSF) also was separated from the same medium. The production of this M-CSF was increased markedly by bacterial lipopolysaccharides. The M-CSF had an apparent molecular weight of 77, 000 in the absence of 0.1 % SDS and 49, 000 in its presence. The G-CSF was stable against 5 mM dithioth-reitol, whereas the M-CSF was slowly inactivated. The two CSFs also differed in their heat-stability and resistance to trypsin. Neuraminidase changed the isoelectric point of both CSFs. Anti-L cell CSF serum severely inhibited the activity of M-CSF but not that of G-CSF. A 1 : 1 mixture of M-CSF and G-CSF developed colonies of the respective types, both in excess of the number predicted. The RSP-2•P3 G-CSF reported here should prove very useful in the study of differentiation in myeloid stem cells.View full abstractDownload PDF (3440K) -
Susumu Yamamoto, Taijo Takahashi, Akio Matsukage1984 Volume 9 Issue 1 Pages 83-90
Published: 1984
Released on J-STAGE: April 18, 2008
JOURNAL FREE ACCESSImmunofluorescent methods using a monoclonal antibody against chick DNA polymerase α and a rabbit antibody against chick DNA polymerase β demonstrated that both DNA polymerases a and β are present mainly in nuclei of cultured chick embryo cells. Fluorescence produced by anti-DNA polymerase a was more intense in the small granules than in other parts of the nucleus but, fluorescence produced by anti-DNA polymerase 13 was distributed evenly in the nucleus. Cells first were treated with Nonidet P-40, followed by treatment with 50 μg/ml pancreatic DNase and 2 M NaCl in order to prepare the nuclear matrix. Fluorescence produced by anti-DNA polymerase a was still detectable in the granules after these treatments, but most of the fluorescence produced by anti-DNA polymerase β disappeared. Our results indicate that a part of DNA polymerase α is tightly bound to a special structure present in the nuclear matrix which presumably is the DNA replication machinery.View full abstractDownload PDF (3736K) -
Akio Kitamura1984 Volume 9 Issue 1 Pages 91-95
Published: 1984
Released on J-STAGE: April 18, 2008
JOURNAL FREE ACCESSAttachment of the ciliate Paramecium caudatum to surfaces of polystyrene Petri dishes (Falcon 3002) was induced through the mating reaction and by treatment with conjugation-inducing chemicals. A similar induction of attachment took place when cells were treated with phenethylamine or benzylamine, compounds known to make the cell surface more hydrophobic. The possible involvement of hydrophobic interactions on the cell surface during the early stage of conjugation in Paramecium is discussed.View full abstractDownload PDF (559K) -
Koichiro Shiokawa1984 Volume 9 Issue 1 Pages 97-102
Published: 1984
Released on J-STAGE: April 18, 2008
JOURNAL FREE ACCESSA fraction containing acid-soluble materials (PCA-extract) from Xenopus early blastulae preferentially inhibits the incorporation of [3H]uridine into 18S and 28S rRNA in Xenopus neurula cells. Pulse-laneling experiments revealed that whereas tubercidin, a known inhibitor of rRNA processing, produced a marked accumulation of the label in 40S pre-rRNA, Xenopus inhibitor suppressed labeling of the pre-rRNA. When tubercidin was added to cells whose activity for rRNA synthesis had been lowered by the Xenopus inhibitor, there was still an accumulation of label in the pre-rRNA. These results indicate that Xenopus inhibitor suppresses the synthesis of rRNA at transcription rather than at processing.View full abstractDownload PDF (480K)
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