巻号一覧
53 巻, 4 号
選択された号の論文の9件中1～9を表示しています
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VERA D. JANKOVIC-STEJIN, DUŠAN T. KANAZIR1978 年 53 巻 4 号 p. 227-240
発行日: 1978年
公開日: 2007/05/21
ジャーナル フリーThe present cytogenetic study was made on the bone marrow cells of 48 male rats killed after 9 to 17 months following acute whole-body X-irradiation.
We found that exposure to a dose of 700rads of X-rays, delivered to animals at a high dose-rate (100rads/min) resulted in a widespread karyotype variability. The number of cell types were existing independently in the haemopoietic tissue within the first week after irradiation, decreased with time. The selection process of persisting abnormalities as well a further evolution of the cells with new karyotypes to clones, were evident after a month following irradiation. Consequently, the analysis of haemopoietic tissue revealed, in 92% of the late survivors, a genetically heterogeneous cell population in which the number of normal diploid cells decreased to a considerable extent. Clones increased in size with elapsing time from exposure to radiation. Thus, the mean clone cell frequency for animals killed after 9 to 17 months following irradiation ranged from 20.6±3.42% to 61.6±4.26%. Analysis of the data showed a significant positive correlation between development of clones in vivo and the survival time after irradiation (r=0.820; P<0.01). For such a finding, the occurence of large clones especially in the bone marrow of rats with growing tumors was of the great influence. Relationship between the degree of mutagenesis on the chromosome level and the process of tumor advancement is discussed.抄録全体を表示PDF形式でダウンロード (5351K) -
HAJIME ONO, MICHIHARU NAKANO1978 年 53 巻 4 号 p. 241-250
発行日: 1978年
公開日: 2007/05/21
ジャーナル フリーPersistent but reversible changes in the phenotype of a tobacco callus are reported in this paper. The callus (S401) was first isolated as a spontaneous variant which differed in pigmentation (dark grayed green) and friability (very friable and wettish) from its parent callus S4 (yellow and firm) during subculture on Murashige and Skoog medium with 2, 4-D. The callus consisted mainly of small embryonic cells and contained a high level of pectin, especially of water soluble forms, as compared with the S4 callus. Almost no lignified vascular elements were observed.
2, 4-D removal from the medium was accompanied by an increase in lignin and a decrease in pectin content. Peroxidase activity in the callus was low, but the level increased during subculture on the medium without 2, 4-D. Isozymes of peroxidase found in the callus after 2, 4-D removal were the same as those in the S4 callus. When the tissues of S401 grown on the 2, 4-D free medium were placed back on the medium with 2, 4-D, they recovered its original characters. The regenerated plant originated from the S401 callus produced only the S401 type callus.抄録全体を表示PDF形式でダウンロード (1736K) -
I. A NEW METHOD FOR IDENTIFYING ALL CHROMOSOME PAIRSNORI KURATA, TAKESHI OMURA1978 年 53 巻 4 号 p. 251-255
発行日: 1978年
公開日: 2007/05/21
ジャーナル フリーMitotic chromosomes of rice, Oryza sativa L. (2n=24), were all identified by a newly developed technique. A new technique of cell suspending and flame-drying made chromosomes possible to be well flattened and spreaded. Tissue treatment with KCl and enzyme caused segmental differentiation in chromosome stainability with Giemsa. All chromosomes were able to be identified in a single prometaphase nucleus by individual characteristics. Twelve pairs of chromosomes were gradually different in length and composed of 5 metacentrics, 5 sub-metacentrics and 2 sub-telocentrics including a satellited pair.抄録全体を表示PDF形式でダウンロード (1341K) -
TOMIO MIYAMOTO1978 年 53 巻 4 号 p. 257-264
発行日: 1978年
公開日: 2007/05/21
ジャーナル フリーA comparison was made on the relative frequencies of different kinds of dumpy mutations induced by X-rays in mature sperm under oxygen and nitrogen conditions.
The results indicate that (1) the yield of ov and olv exceptions (complete) under oxygen condition is significantly higher than that obtained after the same exposure under nitrogen, thus relatively high O.E.R. value of 3.11 is estimated; (2) the response of ol and lv exceptions (complete) is essentially similar to that of ov and olv ones, although the estimated O.E.R. value of 1.89 is relatively low; (3) however, no such difference is found in the yield of o and v exceptions (complete) between the two kinds of irradiation conditions. The O.E.R. value of 1.68 is calculated; (4) the overall frequency of mosaic dumpy mutations appears to be approximately the same, regardless of conditions irradiated. The O.E.R, value of 1.09 is estimated.
These observations indicate that the magnitude of oxygen effects may be different among the different kinds of dumpy mutations.抄録全体を表示PDF形式でダウンロード (810K) -
KAZUYOSHI KIRITANI, KUNIHARU OHNISHI1978 年 53 巻 4 号 p. 265-274
発行日: 1978年
公開日: 2007/05/21
ジャーナル フリーThe transport systems for entry of branched-chain amino acids in the wild-type strain of Salmonella typhimurium LT2 have been separated into two components by detailed kinetic analysis; the Km values for L-isoleucine are 1μM and 12μM, for L-valine 1.2μM and 29μM, and for L-leucine 0.3μM and 11μM, respectively. Two mutant strains, KA261 (ilvC8, ilvT3, ilv-261) and KA265 (ilvC8, ilvT3, ilv-265), having multiple lesions in the transport systems have been isolated from strain CE4 (ilvC8, ilvT3), defective in the low-affinity-(1) system. Kinetic analysis of the transport for L-isoleucine shows that KA266 (ilvT3, ilv-261) and KA267 (ilvT3, ilv-265), which are ilvC8+ transductants of KA261 and KA265, respectively, are defective in both the high-affinity and the low-affinity-(1) systems, but retain the third (low-affinity-(2)) system (Km: 88 to 118μM) which is not detected in the wild-type and KA203 (ilvT3) strains. Strains KA261 and KA265 require glycyl-L-isoleucine, glycyl-L-valine, glycyl-L-leucine and Ca-pantothenate for growth, whereas the parental strain CE4 requires L-isoleucine and glycyl-L-valine. Glycyl-L-isoleucine and glycyl-L-valine can be replaced by high concentration of L-isoleucine and L-valine in strains, CE4, KA261 and KA265. Transport of L-methionine, L-proline and L-threonine remains normal in the KA261 and KA265 mutants.抄録全体を表示PDF形式でダウンロード (826K) -
KUNIHARU OHNISHI, KAZUYOSHI KIRITANI1978 年 53 巻 4 号 p. 275-283
発行日: 1978年
公開日: 2007/05/21
ジャーナル フリーThree mutants, KA222, KA223 and KA224, derepressed in the transport of branched-chain amino acids were isolated as glycyl-L-leucine-resistant (Gler) strains from an isoleucine-valine-requiring mutant, KA931, of Salmonella typhimurium LT2. These Gler strains grow normally in minimal medium supplemented with L-isoleucine (10μg/ml), L-valine (20μg/ml) and large amounts of glycyl-L-leucine (1mM: 188μg/ml), where growth of the parent strain, KA931, is markedly inhibited. When cells were grown in the absence of glycyl-L-leucine, the Gler mutants incorporated wo- to three-fold higher amounts of L-isoleucine or L-leucine than did KA931. Although the transport activity of Gler strains was repressible by glycyl-L-leucine, the activity in the repressed state was equal to, or even higher than, the activity of KA931 in the unrepressed state. The increment of uptake in the Gler strains is mainly due to derepression of the low-affinity transport system. In the Gler strains, the transport of glycine, L-methionine, and L-proline was normal.抄録全体を表示PDF形式でダウンロード (847K) -
MASAO INOUE, HIRAKU TAKEBE1978 年 53 巻 4 号 p. 285-295
発行日: 1978年
公開日: 2007/05/21
ジャーナル フリーRepair capacities of five mammalian cell strains were measured by colony-forming ability, HCR of UV-irradiated virus, UDS, pyrimidine dimer excision, and semi-conservative DNA replication. Colony-forming ability of UV-irradiated cells was high for human amnion FL cells and mouse L cells, slightly low for African green monkey CV-1 cells, and extremely low for xeroderma pigmentosum cells. HCR of UV-irradiated Herpes simplex virus was high in CV-1 cells, FL and normal human fibroblast cells, low in both XP and L cells. The amount of UDS was high in FL and normal human fibroblast cells, considerably low in CV-1 cells, and essentially no UDS was observed in XP cells. Rate of UDS after UV-irradiation was slower for CV-1 cells than FL and human fibroblast cells. Rate of the excision of thymine-containing dimers from the acid-insoluble fraction during post-irradiation incubation of the cells was rapid in FL and normal human cells and slow in CV-1 cells, and no excision took place in XP cells.
Semi-conservative DNA synthesis was reduced after UV-irradiation in all cell lines, but subsequently recovered in FL, normal human and CV-1 cells. The onset of recovery was 4h after UV-irradiation for FL and normal human cells, but about 6h for CV-1 cells. The apparent intermediate repair capacity of CV-1 cells except for HCR may be related to the slow rate of excision repair. “Patch and cut” model is more favorable than “cut and patch” model to elucidate these results.抄録全体を表示PDF形式でダウンロード (852K) -
TAKEO HONDA, HIROSHI SUZUKI, MASAHIRO ITOH, KAORU HAYASHI1978 年 53 巻 4 号 p. 297-299
発行日: 1978年
公開日: 2007/05/21
ジャーナル フリーPDF形式でダウンロード (1492K) -
YOSHIAKI KITANI1978 年 53 巻 4 号 p. 301-308
発行日: 1978年
公開日: 2007/05/21
ジャーナル フリーA presentation of an aberrant 4:4 ascus was made in colour photomicrograph. Means for the recognition of aberrant 4:4 asci and the possible origin of conversion ascus types were explained. A new method was introduced to extract the fundamental ascus types of the two pairs of chromatid complements from the ascus types of 4-chromatid conversion. A discussion was done on the role of aberrant 4:4 type in choosing one kind of theories from the two which were different in the manner of hybrid DNA formation.抄録全体を表示PDF形式でダウンロード (2221K)
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