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Volume 58, Issue 1
Displaying 1-7 of 7 articles from this issue
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Tosihide H. YOSIDA, Kyoko KAWAHARA1983 Volume 58 Issue 1 Pages 1-9
Published: 1983
Released on J-STAGE: July 25, 2006
JOURNAL FREE ACCESSKaryotypes of a mammary cancer spontaneously developed in the domestic cat were analysed in comparison with those of normal somatic cells (2n=38). This tumor was characterized by having bimodal distribution of chromosome numbers: one at hypodiploid and another at hypotetraploid ranges. Based on comparison of karyotypes between the hypodiploid and hypotetraploid cells, the former was suggested to be developed primarily and the latter by duplication of the hypodiploid karyotype. Malignant transformation of this tumor was assumed to be due to the occurrence of monosomics in some chromosome pairs. Although only 2 per cents of the tumor cells were eudiploid so far they were maintained in in vitro culture, the cell population changed markedly to an eudiploid mode (88%) after storage in deep freezing (-80°C). This phenomenon was explained due to the fact that the diploid cells had a more resistance to the hostile condition than the other cells with altered karyotypes.View full abstractDownload PDF (378K) -
Yoshisuke NISHI, Makiko M. HASEGAWA, Naomichi INUI1983 Volume 58 Issue 1 Pages 11-22
Published: 1983
Released on J-STAGE: July 25, 2006
JOURNAL FREE ACCESSThe effect of post-treatment with caffeine on chromosomes was examined in Chinese hamster V79 cells pretreated with different classes of clastogens. The clastogens tested were ultraviolet light (UV), 4-nitroquinoline 1-oxide (4NQO), N-methyl-N′-nitro-N-nitrosoguanidine (MNNG) and mitomycin-C (MMC).
The most striking effect of caffeine was to enhance production of chromosome pulverization. This enhancing effect was observed with each clastogen, only when they were combined with caffeine. Caffeine itself did not produce pulverizations under the conditions tested. Among the clastogens examined, MMC was the most potent inducer for pulverization followed by UV and 4NQO, while MNNG induced scarecely any. With increase in pulverized chromosomes, other types of aberrations, such as exchanges, were reduced in most cases, except with MNNG. The total aberrations (pulverizations and other aberrations) were increased in all cases by post-treatment with caffeine.View full abstractDownload PDF (713K) -
Hiroko SHIBUYA, Yoshisuke NISHI, Tsuneo KADA, Naomichi INUI1983 Volume 58 Issue 1 Pages 23-31
Published: 1983
Released on J-STAGE: July 25, 2006
JOURNAL FREE ACCESSChinese hamster V79 cells were treated with cyclophosphamide (CP) and various concentrations of S-15 mix in vitro, and then examined for chromosome aberrations, sister chromatid exchange (SCE) and induction of 8-azaguanine (8AG)-resistant mutations. Cells from hamster embryos treated with CP in utero by intraperitoneal injection were tested for drug-resistant mutation. CP caused a marked dose-dependent increase of chromosome aberrations, SCE and drug resistant mutations in V79 cells in the presence of lower concentrations of S-15. The inductions of 8AG-resistant mutations in V79 cells by CP with 1% S-15 were 7.4 times higher than those in the control. Trans- placentral treatment with CP also caused a marked increase in 8AG-resistant mutations of hamster embryonic cells.View full abstractDownload PDF (385K) -
Koichiro TSUNEWAKI, Takashiro YOSHIDA, Seiichi TSUJI1983 Volume 58 Issue 1 Pages 33-41
Published: 1983
Released on J-STAGE: July 25, 2006
JOURNAL FREE ACCESSTo reveal the effects of 20 cytoplasms of Triticum and Aegilops species on seed germination of common wheat, a total of 240 alloplasmic lines were investigated, using the data accumulated in the Laboratory of Genetics, Faculty of Agriculture, Kyoto University, since 1966. The results show reduced seed germination in some alloplasmic lines; this reduction can be attributed to the interaction between the T. timopheevi type cytoplasms (G type) and the nuclei of four common wheats, T. aestivum var, erythrospermum, strain P168, strain Salmon and cv. S-615. All of the alloplasmic lines showing reduced germination frequently showed pre-harvest sprouting.View full abstractDownload PDF (371K) -
Takashi YOSHIDA1983 Volume 58 Issue 1 Pages 43-48
Published: 1983
Released on J-STAGE: July 25, 2006
JOURNAL FREE ACCESSTriticum timopheevi cytoplasm has been reported to induce pre-harvest seed sprouting in common wheat. To establish a relationship between T. timopheevi cytoplasm and the expression of α-amylase isozymes, mature and immature seeds from alloplasmic lines of T. aestivum var. erythrospermum (Tve), cv. Chinese Spring and cv. S-615, having this cytoplasm, and their corresponding normal lines, were studied by the disc-isoelectrofocusing method. No variation was found among the lines tested for α-amylase isozyme bands in the cathodic side. Some of the nodic bands always appear in earlier germination stage in seeds of alloplasmic lines than in those of normal lines. Immature seeds, 10 and 17 days after pollination, from all lines show activity of some anodic bands, but 24 day old seeds reveal no activity except in the alloplasmic Tve line that occasionally shows several active bands. Therefore, the regulation of α-amylase expression during seed development is somewhat disturbed by the T. timopheevi cytoplasm, resulting in the lack of seed dormancy and pre-harvest sprouting.View full abstractDownload PDF (339K) -
Ichizo NISHIYAMA, Tomosaburo YABUNO1983 Volume 58 Issue 1 Pages 51-57
Published: 1983
Released on J-STAGE: July 25, 2006
JOURNAL FREE ACCESSBy colchicine treatment of young seedlings autotetraploids of Avena hirtula (2x, AV=activating value=0.9), A. pilosa (2x, AV=0.5), A. longiglumis (2x, AV=1.7), and an amphiploid A. hirtula-pilosa (4x) were obtained. They were first crossed with some species of which AV had been known. Next, based on the crossing result AV of artificial polyploids was estimated by the method employed in the polar-nuclei activation hypothesis. That is, AV of 2.1 was assigned to A. hirtula (4x), 0.85 to A. pilosa (4x), 3.3 to A. longiglumis (4x) and 1.4 to amphiploid A. hirtula-pilosa (4x). It can be said that AV is nearly doubled if the chromosome number is duplicated, or nearly the sum of both parents′ in amphiploids. Artificial polyploids were surely different in their crossability from that of their original species but not in the crossability system.View full abstractDownload PDF (248K) -
Toshihiko OKADA1983 Volume 58 Issue 1 Pages 59-64
Published: 1983
Released on J-STAGE: July 25, 2006
JOURNAL FREE ACCESSUnder the shift-down condition, threonine, α-ketobutyrate and isoleucine at certain concentrations derepressed the synthesis of acetohydroxy acid synthase and isomeroreductase but did not derepress that of transaminase B or threonine deaminase in Escherichia coli W3110-215.
Leucine and/or valine counteracted the derepressing effect of isoleucine on the synthesis of acetohydroxy acid synthase and isomeroreductase. Leucine and valine in the absence of isoleucine completely inhibited derepression of the synthesis of these enzymes after shift-down. These results suggested that isoleucine at a certain concentration is possibly necessary for the efficient derepression of the synthesis of acetohydroxy acid synthase I coded by the ilvB gene and/or acetohydroxy acid synthase III coded by the ilvHI gene.View full abstractDownload PDF (785K)
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