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Volume 35, Issue 2
Displaying 1-4 of 4 articles from this issue
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Tosihide H. YOSIDA, Takaaki ISHIHARA, Tohru ODASHIRO1960 Volume 35 Issue 2 Pages 35-40
Published: 1960
Released on J-STAGE: May 21, 2007
JOURNAL FREE ACCESSComparative idiogram analysis was made in normal rat hepatic cells and cells of rat ascites hepatoma No. 7974. The idiogram of normal hepatic cells is characterized by 24 rod-type elements (including chromosomes with terminal or subterminal centromeres) and 18 V-type elements (including those with median or submedian centromeres), while the stemline idiogram of the hepatoma is remarkable by the presence of 48 chromosomes, among which 29 are of rod and 19 of V-type. There occur a dot-like element of the smallest size and a V-shaped elements somewhat larger than the other V-shaped ones.
Based on the idiogram comparison between the normal hepatic cells and the hepatoma cells, the conclusion may be possible that the hyperdiploid chromosome constitution of the present hepatoma may have arisen by duplication of some chromosomes and that the stem-cells with 48 chromosomes may have developed as a result of selection during serial transfers as having the best adaptability to the physiological conditions of the host.View full abstractDownload PDF (577K) -
Kazuo SAITOH1960 Volume 35 Issue 2 Pages 41-48
Published: 1960
Released on J-STAGE: May 21, 2007
JOURNAL FREE ACCESSThe chromosomes of the haploid group were studied in male germ-cells of thirty species of Japanese moths with the application of the acetic dahlia squash method. For morphological details of chromosomes, one may refer to Figures 1 to 58. The chromosome numbers here established are shown in Table 1.View full abstractDownload PDF (597K) -
Homare KUWANA1960 Volume 35 Issue 2 Pages 49-57
Published: 1960
Released on J-STAGE: May 21, 2007
JOURNAL FREE ACCESS(1) Three temperature-sensitive mutants were obtained from a microconidial wild type strain of Neurospora crassa. One of them is irreparable at 34°C; that is, it grows as well as the wild type at 23°C, but does not grow on any (including omplete) medium so far tested at 34°C. This mutant was the major subject of this report.
(2) The temperature-sensitive irreparable mutant b39 differs from the parent strain by a single gene mutation. The gene responsible for the irreparable character is located on the first linkage group (mating type chromosome), about 30cM left of the centromere.
(3) This mutant does not inhibit the growth of the other temperature-sensitive strains in the heterocaryotic condition.
(4) The possibility of the accumulation of inhibitory substances by the mutant is unlikely, because the culture filtrate of the mutant did not inhibit the growth of the mutant at an intermediate temperature.
(5) The growth characteristics of the mutant when the culture was transfered from 23°C to 34°C, and from 34°C to 23°C were determined.
(6) The nature of the defect in an irreparable mutant was discussed.View full abstractDownload PDF (822K) -
Takumi TSUCHIYA1960 Volume 35 Issue 2 Pages 58-65
Published: 1960
Released on J-STAGE: May 21, 2007
JOURNAL FREE ACCESSX-ray treatment was applied to dormant seeds of Hordeum spontaneum C. Koch var. transcaspicum Vav. by Matsuda's Type KXC-17 apparatus at 180kVp, 3mA, no filter. The dose was about 13, 500r units. Seventy eight plants in X2 generation which were raised from semi-fertile (fertility less than 50%) X1 plants were cytologically investigated. The results are summarized as follows:
1. Chromosome interchanges were observed in 13 plants from 9 head progenies. One ring of eight, 2 ring of four, and one ring of four were observed in 1, 2, and 9 diploid plants, respectively (Tab. 1).
2. One of two trisomic plants showed the chromosome associations of 1V+5II and 1III+6II at diakinesis and MI, indicating the tertiary nature of the trisomics (Tab. 2).
3. Nucleolus-chromosome relationships were determined in all plants with reciprocal translocations (Tab. 2). The ring of eight (Figs. 4a, b), one of the two rings of four in one of the 2 (4)+(4)-plants and the ring of four in 4 (4)-plants (Figs. 1, 2) were attached to the nucleolus, which showed that a member of the interchange was the nucleolus chromosome (chromosome 6 or g-chromosome).
4. In one plant a complete failure of pairing was observed, almost all of the chromosomes being univalents at diakinesis and MI. The meiotic process was very irregular followed by complete sterility on both female and male sides.
5. The results of Burnham and Hagberg (1956) indicating that the breakage frequency of a certain chromosome varies according to the variety are confirmed.
6. The occurrence of trisomic plants in the progeny of interchange heterozygotes is mentioned.View full abstractDownload PDF (1212K)
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