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Volume 36 (1961)
- Issue 11-12 Pages 403･･･
- Issue 9-10 Pages 307-
- Issue 7-8 Pages 223-
- Issue 5-6 Pages 151-
- Issue 3-4 Pages 55-
- Issue 1-2 Pages 1-
Volume 36, Issue 9-10
Displaying 1-6 of 6 articles from this issue
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Yukinori HIROTA, P.H.A. SNEETH1961 Volume 36 Issue 9-10 Pages 307-318
Published: 1961
Released on J-STAGE: November 30, 2007
JOURNAL FREE ACCESSSeveral F' agents which carry various sizes and different kinds of chromosomal segment have been isolated. These are infective and can determine certain male type of behavior by controlling the oriented transfer of the host chromosome. The F' agent can also pick up genes of the host cell and can exchange these genes with host cell chromosome. This agent has high contagiousness and can multiply faster than the host cell. Cells carrying F' can be cured with acridine treatment. Some F' agents carry chromosomal markers which are transduced when F' infects another cell.
The transductants form stable heterogenotes. Complementing pairs of mutant markers have given the wild type on segregation. Thus segregation, due to crossing over between the chromosome and the chromosomal fragment of F', occurrs within the heterogenote. F' transduces the exogenotic gene with higher frequency than the endogenotic gene. The episomic state of F' can be controlled with Rfd3.
The process of F-duction is quite like as mating process of Hfr.
A hypothesis on the structure of F' and the mechanism of determination of maleness by F' is discussed.View full abstractDownload PDF (630K) -
Masakatsu HORIKAWA1961 Volume 36 Issue 9-10 Pages 319-336
Published: 1961
Released on J-STAGE: November 30, 2007
JOURNAL FREE ACCESSThe effects of various chemical and physical agents (mitomycin C, 8-azaguanine and UV-irradiation) on the cell multiplication and DNA, RNA and protein syntheses of original mouse fibroblastic strain L cells in vitro were determined.
The variant cells resistant to these agents were isolated from the original L cells and some detailed properties of these variants were described. Mitomycin C-resistant cells (LMit cells), which were obtained by several successive treatments of mitomycin C in gradual higher levels showed smaller size in appearance than the original L cells and contained less amounts of protein, although amounts of DNA and RNA contained in LMit cells were not different from those in original L cells. 8-azaguanine-resistant cells (L8-AZ cells) showed no marked difference in the cell morphology, cell multiplication rate and contents of protein, DNA and RNA, from those in the original L cells.
Properties of UV-resistant cells (LUV cells) were almost comparable with those of LMit cells in every point of view.
The appearance of these resistant cells seems to depend on adaptation to or selection by these respective agents rather than on mutagenic actions of these agents.
The cross-resistant phenomenon was found between LMit cells and LUV cells, whereas it was not found between LMit and L8-AZ and between LUV and L8-AZ. These facts suggest that effects of mitomycin C may have something common to those of UV-irradiation, which differ from those of 8-azaguanine.
It was found that the multiplication of LMit cells and of LUV cells was accelerated by filterable substances produced from L cells or from L8-AZ cells, whereas the multiplication of L cells and of L8-AZ cells was not affected by filterable substances from cells of any variants.View full abstractDownload PDF (2454K) -
Mitsuo TSUJITA1961 Volume 36 Issue 9-10 Pages 337-346
Published: 1961
Released on J-STAGE: November 30, 2007
JOURNAL FREE ACCESS1. In the pteridine metabolism of the silkworm, pteridine reductase acts specifically on the reaction step leading from dihydropterin to tetrahydropterin.
2. The enzyme activity of the several tissues was examined in normal animals and in the mutants, lem and leml. In the integument of normal larvae the enzyme activity is strong but in that of the lemon larvae it is weak to very weak. Moreover, the integument of the lethal lemon larvae almost completely lacks this enzyme.
3. In the reciprocal crosses between the +lem/leml individuals and the lem/leml individuals the maternal effect of the gene +lem on pterine reductase could be demonstrated.
4. It is inferred from the experimental results of mutual transplantation of ovaries between normal and lemon larvae that the enzyme activity of the eggs is not determined by the genotype of the eggs but by that of the female in whose body the eggs develop.
5. The maternal effect of +lem on the stage of death of the lethal yellow larvae is discussed.View full abstractDownload PDF (521K) -
Yasumoto KIKUCHI1961 Volume 36 Issue 9-10 Pages 347-351
Published: 1961
Released on J-STAGE: November 30, 2007
JOURNAL FREE ACCESSThe transplantability of the CBA tumor-I was studied in mice of pure and hybrid strains. The tumor under study is one of spontaneous mammary adenocarcinomas originally developed in a purely inbred mouse of CBA/Mk strain.
It was found that this tumor was wholly transplantable to mice of original CBA/Mk strain giving 100 per cent lethal takes. For mice of EM-agouti and C3H/He strains which are the same in origin to the CBA/Mk strain, the tumor showed a relatively high transplantability giving over 85 per cent lethal takes. In striking contrast, the tumor gave low- or non-transplantability, showing 0 to 5.3 per cent takes (Table 1) for mice of the following 10 strains: A/He, AKR/Ms, C57BL/6, DBA, dd, DM/Mk, EM-black, MT, NH and Swiss-albino. From the above results, it is evident that the CBA tumor-I here concerned is one of highly strain-specific tumors, and that the CBA/Mk, C3H/He and EM-agouti mice are highly susceptible to that tumor, while the mice of other 10 strains are non-susceptible.
The results of tumor transplantation tests with F1, F2 and backcross hybrids derived between resistant strains (C57BL/6 and EM-black) and a susceptible strain (CBA/Mk) furnished an evidence indicating that the CBA tumor-I possessed at least one histocompatibility factor (Table 2).View full abstractDownload PDF (400K) -
Shunsuke YANO1961 Volume 36 Issue 9-10 Pages 352-358
Published: 1961
Released on J-STAGE: November 30, 2007
JOURNAL FREE ACCESSThe present paper deals with the alteration of cell-population of the MTK-sarcoma III caused by X-irradiation.
The X-rays were given to rats with whole body exposure at a dose level of 1, 500r or 500r on the 3rd day of transfers of the tumor. Samplings of tumor cells for cytological study were made from the treated animals at 72 hours after X-irradiation, and the tumor cells were colored either with acetic dahlia or acetic orcein by means of the water pretreatment squash method.
The occurrence of two tumor-cell populations was remarkable in the MTK-sarcoma III: One consists of tumor cells having the diploid number at 96.2 per cent and the other is those having near-tetraploid number at 3.8 per cent. When the tumor was irradiated with X-rays at a dose level of 1, 500r, tumor cells showing a near-tetraploid chromosome-number mode appeared at about 40 per cent. In irradiated rats, the tumor cells containing 40 chromosomes showed 34.6 per cent, while those having 76 chromosomes was 9.25 per cent in frequency. It is noticeable that about 20 per cent of tumor cells after irradiation were characterized by outstandingly large marker M-chromosomes which have not been found in tumor cells of untreated rats. It is further interesting to note that the near-tetraploid cells showed an increase in population after X-irradiation.
The fate of X-ray-induced tetraploid cells was studied: A part of tumor ascites after irradiation was transplanted into untreated rats, and the other part was inoculated into the rats irradiated previously with X-rays at 1, 500r or 500r. The results showed that the neartetraploid cells gradually decreased in number during a period from 1 to 7 transfer generations, while the tetraploid cells survived rather longer in the irradiated rats than in the untreated ones. It seems likely that the tetraploid cells induced by X-irradiation may be able to favourably grow under a new physiological condition of host animals induced by X-rays.View full abstractDownload PDF (891K) -
Chozo OSHIMA1961 Volume 36 Issue 9-10 Pages 359-376
Published: 1961
Released on J-STAGE: November 30, 2007
JOURNAL FREE ACCESSSince insecticides have been used for controlling insect pests, many species among them have become resistant. Such a phenomenon is presumed to be an example of “rapid evolution”. Then, it should be interesting to study insecticide resistance by the method of population genetics from the view points of evolution mechanism. Although the fruit fly, Drosophila, is not included in the insect pests, it is the best material for a genetic analysis of its resistance by utilizing its many mutant genes. The experimental results obtained with Drosophila could furnish useful information for studying the resistance of insect pests, such as house fly, mosquito etc.View full abstractDownload PDF (972K)
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