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Volume 41 (1966)
- Issue 6 Pages 413-
- Issue 5 Pages 351-
- Issue 4 Pages 259-
- Issue 3 Pages 175-
- Issue 2 Pages 93-
- Issue 1 Pages 1-
Volume 41, Issue 3
Displaying 1-9 of 9 articles from this issue
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III. PENTAPLOID AGROPYRON HYBRIDS AND GENOMIC RELATIONSHIPS AMONG JAPANESE AND NEPALESE SPECIESSADAO SAKAMOTO, MIKIO MURAMATSU1966 Volume 41 Issue 3 Pages 175-187
Published: 1966
Released on J-STAGE: May 21, 2007
JOURNAL FREE ACCESSCytogenetical studies of eight interspecific pentaploid hybrids among five Japanese and two Nepalese species of Agropyron are reported.
(1) The general characteristics of F1 hybrids were either intermediate between the parents or superior to those of the parent and (2) the hybrids were completely sterile.
From chromosome pairing of F1 hybrids, it was observed that the two genomes of three Japanese tetraploid species, Ag. ciliare, Ag. gmelini and Ag. yezoense, are identical with the corresponding two genomes of Japanese hexaploid species, Ag. humidum and Ag. tsukushiense. Two genomes of Nepalese tetraploid species, Ag. gmelini and Ag. semicostatum, are basically homologous with those found in Japanese species but some chromosomal differentiation must have taken place between Japanese and Nepalese genomes.
Summarizing the results obtained from tetraploid and hexaploid hybrids in the previous paper (Sakamoto and Muramatsu 1966) and the present results from pentaploid hybrids, genomic interrelationships in Japanese and Nepalese species were discussed. Genome formulae for three tetra- and two hexaploid Japanese species, and two tetraploid Nepalese species are given in Table 7.
Cytogenetical studies between Japanese and Nepalese species provide experimental evidences of genomic differentiation by geographical isolation, lasting a long time, of closely related species which are distributed in the same phyto-geographical area, the Sino-Japanese Region.View full abstractDownload PDF (2699K) -
IV. NATURAL HYBRIDIZATION AMONG JAPANESE AGROPYRON SPECIESSADAO SAKAMOTO1966 Volume 41 Issue 3 Pages 189-201
Published: 1966
Released on J-STAGE: May 21, 2007
JOURNAL FREE ACCESSTwo cases of natural interspecific hybridization in Japanese Agropyron were observed in Misima. One is a pentaploid hybrid between Ag. ciliare and Ag. tsukushiense, and the other is a hexaploid hybrid between Ag. humidum and Ag. tsukushiense.
The pentaploid hybrid was highly sterile and no seed setting was observed. It is assumed that in this hybrid combination introgressive hybridization would not occur in natural conditions.
As to the hexaploid natural hybrid, two cases were observed; i.e., one allopatric and the other sympatric. In the allopatric case Ag. humidum and the common type of Ag. tsukushiense were involved, while in the sympatric case Ag. humidum and the early ecotype of Ag. tsukushiense were the parental species. In both cases low seed setting was found from the examination of a considerable number of hybrid clones in natural conditions. From progeny tests of backcrossed plants obtained from the sympatric natural hybrids between Ag. humidum and the early ecotype of Ag. tsukushiense, the following conclusions are drawn: It is quite possible that introgression of characters, such as waxiness, from one species to the other was taking place in the natural populations through backcrossing to the parental species of the F1 hybrids followed by segregation of the characters concerned. Rather quick restoration of fertility in the hybrid progenies made possible the establishment of hybrid swarms in a state of nature having intermingled characteristics of the parental species. However, so far no introgressants have been found yet in the natural sympatric populations of these two species. High sterility of F1 hybrids might be a major cause of restricted introgression.View full abstractDownload PDF (1958K) -
BREEDING OF BAKERS' YEAST-DETERMINATION OF THE PLOIDY AND AN ATTEMPT TO IMPROVE PRACTICAL PROPERTIESNORIO GUNGE1966 Volume 41 Issue 3 Pages 203-214
Published: 1966
Released on J-STAGE: May 21, 2007
JOURNAL FREE ACCESSThe occurrence of tetraploidy in bakers' yeasts was demonstrated by the tetrad analysis of mating type alleles and by the determination of cell-size and cell-weight. It was suggested that the growing behavior of cells, e.g. the cluster-formation, may be related to heterozygosity or homozygosity of mating type alleles rather than to the ploidy. The rate of fermentation of given yeasts in dough and in flour free medium is considered to be under control of a heterozygous genetic constitution, in view of the variation in characters among segregants and among hybrids. In crossing experiments, the characters of hybrids and their segregants proved to be statistically parallel to those of component maters prior to crossing, although accompanied by the unexplainable phenomenon that the rates of fermentation of component maters in dough containing a high concentration of sucrose were reduced when combined in hybrids. “Selection and crossing” is an instrument useful for improvement of the practical characters of yeasts. By this method, the rate of osmo-resistant fermentation was considerably increased over the value of the parent. RD yeasts were extremely low in osmo-resistant fermentation.View full abstractDownload PDF (1160K) -
NORIO GUNGE1966 Volume 41 Issue 3 Pages 215-223
Published: 1966
Released on J-STAGE: May 21, 2007
JOURNAL FREE ACCESSFrequent production of RD segregants was observed in the asci of tetraploid bakers' yeasts. With the intention of elucidating this phenomenon, genetic analysis was attempted. It was demonstrated that the respiration of the given bakers' yeasts is controlled by at least three complementary genes (tentatively denoted as R1/r1, R2/r2 and R3/r3). Heterozygous conditions containing many recessive alleles and segregation of them may account for the peculiar phenomenon in question. RD yeasts due to mutation of each of these respiratory genes were found to be characterized by a loss or instability of the cytoplasmic factor necessary for respiration. In other words, it was confirmed that the presence of the cytoplasmic factor in the yeasts concerned is stable by the existence of dominant genes, R1, R2 (indispensable) and R3.View full abstractDownload PDF (930K) -
TATSURO IKEUCHI1966 Volume 41 Issue 3 Pages 225-232
Published: 1966
Released on J-STAGE: May 21, 2007
JOURNAL FREE ACCESSSome cytological observations were undertaken with special regard to the cellular interaction between HeLa and L cells cultured in the same flask. HeLa cells here under study were characterized by a typical epithelial-like growth pattern with a distinct modal chromosome number at 67, whereas L cells were fibroblast-like in general morphology and showed 66 chromosomes as a modal number. As shown in Figs. 1 and 2, both cell lines showed specific karyotypes clearly distinguishable from each other. Based on the difference in karyotype as well as in general morphology occurring in both cell lines, it was possible to investigate the frequency-distribution of HeLa and L cells in mixed cell populations.
Simultaneous inoculation-experiments with the equal number of cells from the two cell lines resulted in that L cells showed a gradual disappearance from the mixed cell population within 30 days after mixing, and that the population was completely replaced by HeLa cells. In the early mixed cultures many abnormal L cells occurred, due probably to the effect of the co-existence of HeLa cells. The most prominent abnormality was the formation of cytoplasmic blebs in relatively round and pycnotic L cells.
In the inoculation of HeLa cells in pre-existence of L cells, no such abnormality occurred in L cells, and cells of the latter type gradually disappeared from the mixed cell population.
In virtue of the available data obtained, the reciprocal interaction between the HeLa and L cells were discussed, particularly on possible factors in relation to their growth patterns. Further, some comment pertaining to the cellular contamination in tissue culture was given.
No evidence was provided, of “cell hybrid” formation between HeLa and L cells, so far as the scope of the present study is concerned.View full abstractDownload PDF (2146K) -
TAKASHI ITO, MASAHARU DOMON, TERUTOSHI YAMASAKI1966 Volume 41 Issue 3 Pages 233-240
Published: 1966
Released on J-STAGE: May 21, 2007
JOURNAL FREE ACCESSUV induced adenine-requiring mutation in yeast cells was investigated quantitatively at several wavelengths of monochromatic UV and at maximum photoreversion conditions in the hope of elucidating the nature of mutagenesis. The results may be summarized as follows:
(1) In general, mutant production by UV and the remaining mutant, after subsequent treatment by VL at maximum photoreversion, both increased almost linearly against the UV dose, irrespective of the wavelengths used except for some deviation in the shorter wavelengths.
(2) Photoreversible and non-photoreversible fractions of the induced mutaion were determined by taking the ratios of the above two slopes.
(3) Using a scattering factor of UV at the cell boundary, reliable absolute cross sections of the mutation were obtained for the several wavelengths.
(4) Some implications of the above findings were discussed with special reference to the relation between mutation production and the inducible photochemical changes in DNA bases by UV.View full abstractDownload PDF (830K) -
TAN TAKAYANAGI, SHOZO INOKI, KATSUMI YOSHIKAWA1966 Volume 41 Issue 3 Pages 241-246
Published: 1966
Released on J-STAGE: May 21, 2007
JOURNAL FREE ACCESSIt was found that the members forming a pair between killer and sensitive cells failed to complete further sexual process, because of the loss of adhesive ability in sensitive cells due to a poisonous substance liberated into the medium from killer cells. Evidence was presented for the intraclonal union in a certain clone of P. polycaryum. Some comments were given on the mating reaction and on the intraclonal union.View full abstractDownload PDF (1633K) -
YOSHINOBU SUGINO, AKIKO SORAI, TOKIO KOGOMA, YUKINORI HIROTA, REIJI OK ...1966 Volume 41 Issue 3 Pages 247-249
Published: 1966
Released on J-STAGE: May 21, 2007
JOURNAL FREE ACCESSDownload PDF (206K) -
Jun-ichi Ishidsu, Haruo Ozeki, Tadashi Miyake, Takashi Yura1966 Volume 41 Issue 3 Pages 250-251
Published: 1966
Released on J-STAGE: May 21, 2007
JOURNAL FREE ACCESSDownload PDF (420K)
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