巻号一覧
57 巻, 5 号
選択された号の論文の10件中1～10を表示しています
- |<
- <
- 1
- >
- >|
-
Yoshiaki KITANI1982 年 57 巻 5 号 p. 467-481
発行日: 1982年
公開日: 2006/07/25
ジャーナル フリーApart from the previously studied g-locus, the i-locus showed the following characteristics. I. One-point cross conversion frequencies were roughly constant around 10×10-3, unless associated with a Rec+ factor. II. The interallelic conversion frequencies were either the sum of parental one-point cross conversion frequencies (20×10-3) or still higher than this, suggesting that this locus has compound composition with at least two units. III. Whenever interallelic cross conversion frequency was notably higher than 20 ×10-3, the ascus frequency of the spore colour ratio, 2+, 2i, 4b (asci of this composition can be developed through gene conversion or appear as tetratypes through reciprocal recombination) was high enough to include the excess portion of the conversion frequency, leaving substantial surplus. This suggests that the i-locus is composed of multiple units, and at the joints of units ordinary reciprocal cross-overs occur producing tetratype asci; and cosequently raising the apparent conversion frequencies. IV. The original blu6allele was accompanied with a Rec+ factor, and therefore, its conversion frequency was low. Through gene conversion, this factor was removed from blu6 and transferred to the wild type allele. V. The Rec factor functions as a mutator on the alleles in the i-locus, and by itself, it was labile. Among the above characteristics, III and V respectively show close relationships with the compound genes of Neurospora and the mutable genes of Zea.抄録全体を表示PDF形式でダウンロード (596K) -
Toshihiko OKADA1982 年 57 巻 5 号 p. 483-498
発行日: 1982年
公開日: 2006/07/25
ジャーナル フリーAfter nutritional shift-down, threonine, α-ketobutyrate, or isoleucine with- in certain concentration range stimulated derepression of the synthesis of acetohydroxy acid synthase in strain W3110-215, a low-thymine requiring derivative of Escherichia coli K12. The acetohydroxy acid synthase induced by isoleucine was valine-sensitive. Since chloramphenicol inhibited the increase of the enzyme activity, the increase seemed to be due to enhancement of enzyme synthesis and not to the activation of the enzyme. From these results, it was suggested that not only limitation of leucine or valine, but also the presence of excess threonine or isoleucine is necessary for efficient derepression of the synthesis of acetohydroxy acid synthase.
On the other hand, threonine did not stimulate the derepression of the synthesis of the enzyme in strains W2252 and 58-161, methionine-auxotrophic mutants of E. coli K12, growing in minimal medium containing methionine. When a prototrophic strain with regard to methionine requirement was used, methionine or threonine added in minimal medium derepressed synthesis of acetohydroxy acid synthase, but the simultaneous addition of the two compounds did not give any synergistic effect on the enzyme synthesis. The mechanisms of these phenomena are unknown.抄録全体を表示PDF形式でダウンロード (689K) -
Yasunari OGIHARA1982 年 57 巻 5 号 p. 499-511
発行日: 1982年
公開日: 2006/07/25
ジャーナル フリーThe chromosomal variations occurring during the subculture of Haworthia setata (2n=14) calluses that had originated from a single callus induced from a flower bud, repeatedly subdivided in the first four culture generations, and successively subcultured for six more generations were examined. The frequency of diploid cells remained constant during subculture (ca. 50%), but that of the tetraploids gradually increased. Both hyperdiploid and hypo- or hypertetraploid cells remained as minor fractions. But, the frequency of hypodiploid cells was changeable. Though chromosome number differed significantly among some culture generations, its variation did not increase with advanced culture generations. A new variant karyotype, 7L+1M+6S, was first observed in the third culture generation, and came to constitute the modal class in three of the four primary clones, replacing the normal diploid karyotype (8L+6S). A selecting force to maintain the euploids, including the 7L+1M+6S type, was operating during callus growth. Structural changes of chromosomes found in the Haworthia callus were similar to those reported in other materials, i.e., deletions, translocations, dicentric and acentric fragments. All of the chromosomes were broken in the interstitial region, and not in the centromeric region.抄録全体を表示PDF形式でダウンロード (924K) -
Koichiro TSUNEWAKI1982 年 57 巻 5 号 p. 513-525
発行日: 1982年
公開日: 2006/07/25
ジャーナル フリーIn order to provide a genetic basis for fertility restoration by a common wheat, Triticum aestivum cv. Chinese Spring against the cytoplasm of Aegilops ovata, two sets of monosomic analysis have been carried out. From the results, the following conclusions were drawn: (1) Rfo2 gene, a key factor on chromosome 1B of Chinese Spring restores in its double dose selfed seed fertility to above 25%, (2) in its single dose the presence of a factor on chromosome 7A and another factor either on chromosome 5A or 5B, both in double dose, is necessary to assure the same level of fertility restoration, (3) absence of the key gene (Rfo2) causes complete sterility, and (4) modifiers which improve the level of fertility restoration to some extent are located on chromosome 1A, 4A and 7D of Chinese Spring. Since the single dose of Rfo2 gene can not restore fertility to above 25% when other restoring genes are in heterozygous condition, utilization of this gene in breeding both hybrid wheat and bred-true, fertile line with the ovata cytoplasm is greatly limited. The results provided another example of the linkage between fertility- restoring gene and a nucleolus-organizing region.抄録全体を表示PDF形式でダウンロード (548K) -
Takeshi SETO, Yasuaki UTSUNOMIYA, Taeko UTSUNOMIYA1982 年 57 巻 5 号 p. 527-534
発行日: 1982年
公開日: 2006/07/25
ジャーナル フリーThe karyotypes of Tylototriton andersoni Boulenger were studied. This species is known to be an endemic salamander of the Ryukyu islands and may be the most primitive species of the Salamandridae. Somatic chromosomes (2n=24) prepared from intestinal tracts of adult males and females were examined with both conventional Giemsa stain and the BSG technique. Karyological characteristics of the primitive species was recognized in comparison with other Japanese newts Cynops pyrrhogaster and C. ensicauda. The C-band pattern also indicated the dissimilarity with other examined species of more advanced salamandrids. No heteromorphic pair of chromosomes was detected between male and female karyograms prepared with either conventional Giemsa or the C-banding method.抄録全体を表示PDF形式でダウンロード (391K) -
Samuel H. HORI, Soichi TANDA, Kazuki FUKAZAWA, Takaomi HANAOKA1982 年 57 巻 5 号 p. 535-550
発行日: 1982年
公開日: 2006/07/25
ジャーナル フリーIn a previous study, we reported the presence in Drosophila melanogaster of a modifier gene system which has influence on activities of three X-linked enzymes, G6PD, 6PGD and HAD. However, possibilities exist that the system may be primarily responsible for other traits which have influence on the enzyme activities. In order to examine these possibilities, the high- and low- activity lines established from a strain which is homozygous for an X chromosome were compared with respect to the following parameters: average size and total number of wing cells, protein, DNA and ribosomal RNA contents, total G6PD activity, distribution of G6PD, 6PGD and HAD activities, and synthetic and degradation rates of 6PGD. Effects of juvenile hormone and ecdysone on G6PD and 6PGD activities were also studied. The results obtained were all consistent with our assumption that the modifier gene system may be primarily responsible for the control of the X-linked enzyme genes.抄録全体を表示PDF形式でダウンロード (854K) -
Akio HYODO, Hitoshi UEDA, Fusaho TAKEI, Ken-ichi KIMURA, Kensuke SHIMU ...1982 年 57 巻 5 号 p. 551-560
発行日: 1982年
公開日: 2006/07/25
ジャーナル フリーFibroin gene expression in the posterior silk gland of normal strain (J-131/J-131), Nd strain (Nd(2)/Nd(2)) and their hybrid (J-131/Nd(2)) silkworms was compared on the levels of fibroin and fibroin mRNA production. The syntheses of both fibroin and fibroin mRNA in the Nd(2) and the hybrid silkworms were greatly reduced when compared with those of the normal silkworm. This result indicates that the Nd(2) gene represses dominantly fibroin gene expression, presumably at the level of transcription of fibroin gene. Estimation of gene products (fibroin and fibroin mRNA) from two fibroin alleles, Fnor and SNd, of the hybrid silkworm, J-131/Nd(2), demonstrates that the expression of the fibroin allele SNd derived from Nd(2) mutant strain is more severely repressed than that of the fibroin allele Fnor derived from J-131 strain.抄録全体を表示PDF形式でダウンロード (479K) -
Takao K. WATANABE, Muneo MATSUDA, Seido OHNISHI, Fuyuo HIHARA1982 年 57 巻 5 号 p. 561-567
発行日: 1982年
公開日: 2006/07/25
ジャーナル フリーTwo different species which were originated from India and Indochina have been called Drosophila jambulina as the same species. They were compared genetically, cytologically and electrophoretically, as well as morphologically. From these results it was concluded that the Indian species was the realD. jambulinaand that the Indochinese species seemed to be a new species and was tentatively namedD. punjabiensis-likebecause it was closer to the sibling species, D. punjabiensis. D. jambulinashowed a color dimorphism in a terminal tergite of female. A light-type gene controlling the dimorphism was dominant over a dark-type gene. The heterozygote segregated into 3 light: 1 dark in the next generation.抄録全体を表示PDF形式でダウンロード (334K) -
Kazuo FUJIKAWA1982 年 57 巻 5 号 p. 569-574
発行日: 1982年
公開日: 2006/07/25
ジャーナル フリーWhen male larvae carrying unstable white-zeste system were fed on a medium containing 50 and 100ppm AF-2, the incidence of somatic eye-color mutations increased approximately linearly. Since the spontaneous mutation frequency is 0.1%, the doubling dose of AF-2 is estimated at 16ppm. However, when AF-2 dose of 300ppm was given orally to adult females, the incidence of recessive visible mutations at dumpy locus and dominant visible mutations at Minute loci in primary oocytes did not increase above the control level. This indicates that the somatic mutation assay is more sensitive than the germ-cell-mutation assay, at least, after treatment with AF-2 under the conditions used.抄録全体を表示PDF形式でダウンロード (257K) -
Masahito T. KIMURA1982 年 57 巻 5 号 p. 575-580
発行日: 1982年
公開日: 2006/07/25
ジャーナル フリーInheritance of cold hardiness and sugar contents were studied at the imaginal stage in Drosophila takahashii and D. lutescens. The latter species was more resistant to cold stress than the former. In D. lutescens, the cold hardiness improved by the low temperature acclimation at 5 or 10°C, but such effect of acclimation was not observed in D. takahashii. The F1 progeny between these two species showed the intermediate resistance between the parental species, and the backcross progeny showed the intermediate between F1 and the parental species. This suggests that their cold hardiness was controlled by a gene or genes mainly located on autosomal chromosomes.
The trehalose content was somewhat higher in D. lutescens than D. takahashii and the content increased as culturing temperature decreased in both species, but its role in the cold hardiness of these species was not clear.抄録全体を表示PDF形式でダウンロード (229K)
- |<
- <
- 1
- >
- >|