The Japanese Journal of Genetics
Online ISSN : 1880-5787
Print ISSN : 0021-504X
ISSN-L : 0021-504X
Volume 30, Issue 2
Displaying 1-5 of 5 articles from this issue
  • III. MALDEVELOPMENT OF THE CENTRAL NERVOUS SYSTEM, EYE, AND MANIFESTATION OF HEART ABNORMALITIES
    Ujihiro MURAKAMI, Yoshiro KAMEYAMA
    1955 Volume 30 Issue 2 Pages 51-61
    Published: 1955
    Released on J-STAGE: May 21, 2007
    JOURNAL FREE ACCESS
    1. More than thirty pregnant mice were administered with a single intravenous injection of 1cc, of 1 per cent trypan blue aqueous solution on their 6th, 7th, 8th, and 9th day of pregnancy and from them thirty mothers were selected, whose embryos were examined and their prognoses were clear. Almost all embryos were examined on their 13th embryonic day.
    2. Normal embryos and retarded embryos without abnormalities were manifested most in D group, next in the C group, and least frequently in the G group. That is, the earlier administered, the fewer embryos without abnormalities were manitested.
    3. More abortions were also observed in the F and G group than in the D and C group.
    4. More abnormalities found to be alive on the 13th day of pregnancy were manifested in C group administered on the 8th day of pregnancy than in other groups. In group E administered on the same day of pregnancy, fewer abnormal embryos were found than in group C. However, in group E, more various kinds of gross abnormalities were manifested than in other groups. Therefore a certain racial difference seems to be present.
    5. In general, central nerve abnormalities were manifested in various conditions in each group. They seem to result from the process of hyperplasia or mal-closure of the medullary tube.
    6. Abnormal embryos with seriously malformed central nervous system were usually found dead on the 10th-12th day of pregnancy. The head formation in these cases were small and often associated with enlarged pericardium. More of the secases were found in group F than in the other groups.
    7. Marked abnormalities except those of the central nervous system were as follows: malformed eyecup, anophthalmos, median harelip associated with pseudencephaly, dextrocardia, ectopia cordis and other abnormal conditions of the heart anlage, taillessness and blister formation etc..
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  • XVII. Seed development in tetraploid rice
    Man-emon TAKAHASHI
    1955 Volume 30 Issue 2 Pages 62-70
    Published: 1955
    Released on J-STAGE: May 21, 2007
    JOURNAL FREE ACCESS
    As compared with diploids the embryo-sacs of tetraploid rice plants are of a larger size with larger cells and nuclei. The fertilized ovule, on the other hand, develops at a slower pace than the diploid and the differentiation is somewhat less than in the diploid. The tissual size of the tetraploid ovule is not as large as would be expected from calculations based on nucleo-plasmic ratio and cell eutery.
    While the tetraploid ovules, at the flowering stage, have an average of 60% of normally organized embryosacs, after flowering and with the lapse of time, the frequencies of their appearance decreases. In matured kernels, the frequencies of fully developed kernels are less than 40% and aside from completely undeveloped sterile kernels, a certain proportion of underdeveloped kernels, shrivelled in outward appearance, are found.
    Histologically, the lack of embryo, the absence of normal egg apparatus and the post-fertilization mortality at an early stage of the development results in sterile kernels, and the belated, unproportional and parthenocarpic development of ovules are responsible for shrivelled kernels, in which the development of the endosperm is inhibited to a greater extent than that of the embryo. When nursed in artificial culture a certain number of the shrivelled kernels germinate.
    Plants grown from well developed kernels generally have normal tetraploid chromosomes with 2n=48, whereas plants from shrivelled kernels are found to be both tetraploid and hypo-tetraploid. Though it is not yet possible to ascertain the presence of hyper-tetraploids, as in certain tetraploid plants, it is obvious that the tetraploid rice plant is not quite stable, cytologically speaking.
    In paddy field cultivation in Hokkaido which is the northern most island of Japan, however, the tetraploid is rather stable and the author has been unable to find out any aneuploid plants which in the normal sense of thinking should expected to be present since the mother plants are tetraploids. This stablity may be due to a strong selectivity of unfavourable environmental conditions, which affects the germination of aneuploid kernels.
    As to the causes of low seed fertility of the tetraploid rice plant, it is too well known to be repeated here that the primary cause is the aneuploidy resulting from irregularities in the meiosis, but in addition to the above, it is highly probable that an inherent weakness of the tetraploid mother tissue plays a certain role.
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  • Hiroshi NAKAHARA
    1955 Volume 30 Issue 2 Pages 71-77
    Published: 1955
    Released on J-STAGE: May 21, 2007
    JOURNAL FREE ACCESS
    The present author, while studying the course of divison of living tumor cells of the MTK-sarcomas of rats by phase microscopy, has met with a remarkable transformation of spherical tumor cells into unusual shapes as seen in leucocytes and fibroblasts. The observations were carried out with the hanging-drop preparations mounted with fresh tumor ascites containing tumor cells at a temperature of 35°C.
    The shapes of the tumor cells after transformation at 35°C is characteristic to the strain of the tumor. The tumor cells of the MTK-I showed a leucocyte-like feature in transformation, while those of the MTK-II and-III exhibited the shape of fibroblasts after transformation. By placing the transformed cells at low temperature, they become spherical in shape, but with the rise of temperature they transform again into unusual forms.
    The transformed tumor cells are remarkable in containing filamentous mitochondria which show a parallel orientation along marked cytoplasmic flow. It was assumed after considerations that the transformation in shape of the tumor cells might be a phenomenon associated with a certain cellular activity in the course of the growth of the tumor.
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  • III. The digestion-method of the nucleus
    Akira YUASA, Tadashi HIRANO, Osamu SUZUKI
    1955 Volume 30 Issue 2 Pages 78-82
    Published: 1955
    Released on J-STAGE: May 21, 2007
    JOURNAL FREE ACCESS
    The cells of Mycobacterium 607, after being cultured for 24 or 48 hours on Oka-Katakura's culture- medium, were treated with the fluid of DNase or RNase or the mixed fluid of DNase and RNase for 10min., 30min., 1h., 2h., 3h., 4h., 5h., 6h., or 7h. The action of the enzyme was stopped by drying or by treating with 1N HCl. The enzyme which was used in this research was mixed with distilled water or Veronal-Buffer (pH=7.4). The temperature at which the enzyme acted was 35-37°C in the case of DNase and 60°C in the case of RNase.
    By the action of DNase, the nuclei were digested, did not stain with the aqueous solution of gentian violet and showed negative reaction to Feulgen's nucleal staining.
    By the action of RNase, the form of the cell was somewhat deformed.
    By the action of DNase, DNA in the nucleus seems to diffuse out into the cytoplasm.
    From these results it is supported that the nucleus of Mycobacterium 607 contains DNA and is equevalent to the nucleus of the higher plant. It is also presumed that the cytoplasm of this bacterium contains RNA.
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  • (1). On the nature of pterin obtained from the yellow lethal strain
    Mitsuo TSUJITA, Bungo SAKAGUCHI
    1955 Volume 30 Issue 2 Pages 83-88
    Published: 1955
    Released on J-STAGE: May 21, 2007
    JOURNAL FREE ACCESS
    In a previous paper, M. Tsujita, one of the authors, has reported on the allelic relation of yellow lethal to lemon in the silkworm, as well as on the maternal inheritance of yellow lethal. Subsequently, we are now carrying on genetical and biochemical studies of the yellow lethal larvae. As the first step, pterins and other fluorescence compounds contained in the yellow lethal larvae were investigated. This paper deals with this experimental results.
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