All issues
Successor
Volume 41, Issue 1
Displaying 1-7 of 7 articles from this issue
- |<
- <
- 1
- >
- >|
-
NOBUO TAKAGI, TOKUTARO MAKITA, HATAO KATO, SHUDO TAKAI, MASAHIRO HIKIT ...1966 Volume 41 Issue 1 Pages 1-7
Published: 1966
Released on J-STAGE: May 21, 2007
JOURNAL FREE ACCESSChromosomes of 40 sexually abnormal human subjects were surveyed in this study. Diagnostic and clinical features of patients are shown in Table 1, and chromosomal information obtained is summarized in Table 2. The XXY sex-chromosome constitution was detected in 6 Klinefelter's syndrome cases and the XO mechanism in a Turner's syndrome patient. Thirty-three cases clinically having sex anomalies were found to possess in each an apparently normal chromosome complement both numerically and morphologically.View full abstractDownload PDF (1362K) -
TOSIHIDE H. YOSIDA, YOSHINORI KURITA, KAZUO MORIWAKI1966 Volume 41 Issue 1 Pages 9-15
Published: 1966
Released on J-STAGE: May 21, 2007
JOURNAL FREE ACCESSThe karyotypes of original solid and transformed ascites type tumors of plasma cell neoplasm X5563 were compared with special regard to the electrophoretic serum pattern of mice bearing these tumors. Both lines were characterized by a wide tetraploid range of chromosome number variation. The chromosome number in stemline cells was 84 in both solid and ascites lines, but their karyotypes were different. The solid form had one submedian metacentric (SM) and one subtelocentric (ST) chromosome as markers, and the latter had two SM-, one ST- and one minute (m). The electrophoretic pattern of γ-globulin found in mice bearing solid and ascites tumor was similar. The observed stability of γ-globulin was discussed in relation to the tetraploidy ofthe neoplasms.View full abstractDownload PDF (1892K) -
AKIO MURAKAMI1966 Volume 41 Issue 1 Pages 17-26
Published: 1966
Released on J-STAGE: May 21, 2007
JOURNAL FREE ACCESSIn order to get mutational RBE of fast neutrons in mature sperm of the silkworm, irradiation was perfomed at late pupal stage. A series of 137Cs γ-ray irradiation experiments were run in parallel with those 14MeV neutrons. For the determination of mutation frequency visible recessive egg colour mutations were used as markers.
1.Dose-frequency curves for recovered mutations increased linearly with the increasing dose for both radiations, which indicates that they are due to single-hit events. Whereas, the frequency curves for mosaics, were rising non-linearly, indicating that they are of multi-hit nature.
2. 14MeV neutrons were approximately 6 times as efficient as γ-rays in producing recessive visible mutations in mature sperm of the silkworm. Hence, RBE values of 14MeV neutrons are larger in mature sperm than in spermatogonia.
3. For the production of mosaics RBE of 14MeV neutrons relative to 137Cs γ-rays was about 5.View full abstractDownload PDF (1015K) -
ICHIZO NISHIYAMA, NOBUMICHI INOMATA1966 Volume 41 Issue 1 Pages 27-42
Published: 1966
Released on J-STAGE: May 21, 2007
JOURNAL FREE ACCESSEmbryological studies were made to clarify the developmental processes leading to seed collapse following crosses between diploid Brassica chinensis (2x=20) and autotetraploid Brassica pekinensis (4x=40).
It was observed that the hybrid embryos from the reciprocal crosses appeared to develop normally in the early developmental stage, but they generally failed to develop beyond the globular stage as the degeneration of endosperm progressed. Exceptionally, a few triploid plants were obtained from the 4x (_??_)×2x (_??_) cross.
In 2x×4x crosses, cell wall formation in the endosperm was completely inhibited, and there occurred abnormal vacuolization in endosperm which was accompanied with various nuclear irregularities, resulting in a complete degeneration of whole endosperm, including embryo, in all ovules.
In 4x×2x crosses, the amount of endosperm was smaller but cell wall formation took place earlier than in the parents. However, the endosperm, including embryo, was disintegrated around 15 days after pollination.
The possible cause of seed failure was discussed considering various abnormalities observed during the developmental stages.View full abstractDownload PDF (8281K) -
TOSIHIDE H. YOSIDA1966 Volume 41 Issue 1 Pages 43-58
Published: 1966
Released on J-STAGE: May 21, 2007
JOURNAL FREE ACCESSKaryotypes in several lines of the mouse lymphocytic neoplasm, P388, growing in vivo and in vitro, were examined. Parental ascites line (P388) was characterized by stemline cells with 41 telocentric chromosomes. Modal chromosome number of another ascites subline, P388/L, was 44, all being of telocentric type. Although all chromosomes in these two lines were telocentric, the length of chromosomes was considerably different from that of normal somatic ones. On the other hand, P388/P line, adapted to in vitro culture, was remarkable by a drastic change of karyotype, the new one consisting of telocentric, median and submedian metacentric chromosomes. The majority of cells of this line had 34 telocentric, 11 median metacentric and 4 submedian metacentric chromosomes. Four single-cell clones derived from the P388/P line had similar karyotypes to that of the parental line, but chromosome number, length of chromosomes and arm index of metacentric chromosomes were slightly different. The P388/R-26 line which was developed by reinoculation of culture-adapted cells into mice had also complicated karyotypes like the parental cultured line, but the chromosome number, especially that of metacentric chromosomes, was lower. Based on the above investigations, the relation between chromosome alteration and growth capacity of tumor cells were discussed.View full abstractDownload PDF (3719K) -
TOSIHIDE H. YOSIDA1966 Volume 41 Issue 1 Pages 59-74
Published: 1966
Released on J-STAGE: May 21, 2007
JOURNAL FREE ACCESSChromosome patterns were examined in the parental sensitive, 8-azaguanine (AZG) and amethopterin (AMT) resistant lines of the lymphocytic neoplasm, P388, growing in vitro. The karyotype of the sensitive P388/P line was characterized by a modal chromosome number of 49, which included 15 metacentrics. However, the karyotypes of some of the drug resistant lines were quite different from that of the sensitive line from which they were derived. An increase of chromosome number was found in resistant lines (102B AZG, 102H AZG and 146D AMT) developed by treatment with rather low drug concentrations. Secondarily a decrease in chromosome numbers accompanied even greater resistance (102J AZG and 146J AMT) which had been achieved by treatment with increased concentrations of drugs. In the case of the AZG- resistant lines (102H and 102J), a decrease of submedian metacentric chromosomes was noted. in the AMT-resistant line (146J) there was decrease of telocentric chromosomes. The possible relationship between the development of drug resistance and changes in chromosome pattern was discussed.View full abstractDownload PDF (6578K) -
MASAHIDE ISHIBASHI1966 Volume 41 Issue 1 Pages 75-89
Published: 1966
Released on J-STAGE: May 21, 2007
JOURNAL FREE ACCESSTwo Hfr strains which had recieved the thymine requiring mutation of strain 15T-, but the colicinogenic factor were isolated. Mating experiments with these Hfr's revealed that thymine starvation of Hfr cells inhibits chromosome transfer. Uracil and histidine double starvation in Hfr cells, rather than being inhibitory, protects them from the spontaneous interruption of the process. The inhibitory effect of thymine starvation is differentially active, the more distant from the origin of an Hfr chromosome a given genetic marker is located, the more strongly transfer of that marker is inhibited. This inhibitory effect is (at least, partially) reversible.View full abstractDownload PDF (1435K)
- |<
- <
- 1
- >
- >|