遺伝学雑誌
Online ISSN : 1880-5787
Print ISSN : 0021-504X
ISSN-L : 0021-504X
51 巻, 1 号
選択された号の論文の9件中1~9を表示しています
  • NORIAKI EBITANI
    1976 年 51 巻 1 号 p. 1-10
    発行日: 1976年
    公開日: 2007/05/21
    ジャーナル フリー
    As a part of the study in which the maintenance of esterase isozyme polymorphisms of D. virilis is experimentally analyzed, the effects of esterase activity on two major components of fitness, fecundity and larva-to-adult viability, were studied by using a null strain (00/00) having very low esterase activity in comparison with an ordinary 7B/7B strain. The following three experiments were performed: 1) Fecundity and larva-to-adult viability under near optimal conditions. 2) Larva-to-adult viability in mixed cultures. 3) Larva-to-adult viability under competitive conditions in which three genotypes coexist at various frequencies.
    In Experiments 1 and 2, there were no significant differences in the component of fitness among three homozygous genotypes (00/00, 0B/0B and 7B/7B). In Experiment 3, in which larvae of three genotypes (00/00, 00/7B and 7B/7B) coexist in the Hardy-Weinberg ratio, the heterozygotes seem to be slightly superior to both homozygotes in the larva-to-adult viability but the viability did not differ between two homozygotes having quite different esterase activities. The heterozygote superiority could be ascribed to the heterotic effect of a gene block including two esterase loci on the second chromosome. No evidence of frequency-dependent selection was recognized in Experiment 3.
    From the results summarized above it could be concluded that there may be little effect of esterase activity on two components of fitness, fecundity and viability, and that selective differences among genotypes at two esterase loci are very small, if any.
  • KANJI ONO
    1976 年 51 巻 1 号 p. 11-18
    発行日: 1976年
    公開日: 2007/05/21
    ジャーナル フリー
    In the present investigation calluses of Marchantia polymorpha produced from female gemmae were subcultured in the various media, and cytological observations were made on these calluses and the thalluses restored from calluses.
    In 4 media used for subcultures, M-4 medium (a modified Miller's medium supplemented with 10% coconut milk) promoted the growth of calluses most effectively, and M-3 medium (a modified Miller's medium supplemented with 500ppm casamino acid) promoted the next. M-2 medium (a modified Miller's medium) and M-1 medium used for inducing the calluses, however, did not promoted as much.
    The observations of chromosomes in calluses showed that the number of abnormal cells like polyploid and aneuploid increased in contrast to the number of normal haploid cells as a result of subcultures. The frequency of the abnormal cells was found to be the highest in M-4 medium.
    When light was illuminated on the calluses which were cultured in the dark, without changing the medium, the calluses soon turned green and grew further. The restored thalluses could be easily obtained by culturing the calluses in the inorganic media. It was found that among the restored thalluses diploid (n=18) and aneuploid (n=12, 14) thalluses were included in addition to many normal haploid thalluses (n=9).
  • I. DEVELOPMENTAL TIME AND PRE-ADULT VIABILITY
    SEIDO OHNISHI
    1976 年 51 巻 1 号 p. 19-25
    発行日: 1976年
    公開日: 2007/05/21
    ジャーナル フリー
    Using the Oregon-R strain of Drosophila melanogaster, the pre-adult fitness components of developmental time and viability were estimated under various environmental conditions of larval density and temperature. The results show that: (1) The eclosion patterns acquired a circadian rhythm under fluctuating temperature conditions. (2) Developmental time was delayed not only by increasing larval density, but also by fluctuating temperature. (3) Though the pre-adult viability decreased with increasing larval density, it did not decrease with fluctuating temperature. (4) The correlations between developmental time and pre-adult viability under the constant and fluctuating temperatures were -0.55 and -0.31, respectively. (5) The coefficients of variation for pre-adult viability were larger than those for developmental time. Moreover, under the fluctuating temperature and in the low larval density, they were larger than under the constant temperature and in the high larval density.
    These results suggest that in general the pre-adult fitness components are strongly influenced by environmental conditions. The fitness components, therefore, must be carefully estimated by considering the effects of environmental conditions.
  • MOTOI MURATA, IZUO TOBARI
    1976 年 51 巻 1 号 p. 27-37
    発行日: 1976年
    公開日: 2007/05/21
    ジャーナル フリー
    From the laboratory population of D. melanogaster which had been exposed, in every generation, to a dose of 2kR of gamma rays for about 100 generations, three experimental populations were initiated and maintained without further irradiation. Frequency of lethal second chromosomes and their allelic rate were repeatedly examined in these populations.
    Frequency of lethal chromosomes was gradually reduced and from the rate of this reduction the heterozygous effect of induced lethal genes was estimated to be about 2%. Unlike the result of our previous experiment, this value was almost constant over all generations. From the result of the allelism tests it was demonstrated that the induced lethal genes were maintained in the irradiation suspended populations, being fairly influenced by the effect of random genetic drift.
  • 1. PURIFICATION AND CHARACTERIZATION OF THE MEMBRANE PROTEIN FROM PTERIDINE GRANULES OF A NORMAL STRAIN
    SUSUMU SAKURAI, MITSUO TSUJITA
    1976 年 51 巻 1 号 p. 39-52
    発行日: 1976年
    公開日: 2007/05/21
    ジャーナル フリー
    The membrane protein of pteridine granules produced in the larval hypodermis of a strain of normal silkworm larvae was isolated and its chemical composition analysed. This protein is composed almost entirely of protein and lipid. The protein content makes up 65-68% of the dry weight, the lipid content, 31-33% and the carbohydrate content, 1.1-1.4%. The amino acid composition of the membrane protein of normal granules is shown. Essentially this amino acid composition is very similar to that of structural membrane proteins from other species.
    Using several different solvents, the solubility of the membrane protein was tested. The membrane protein is readily soluble in sodium dodecyl sulfate urea solution. It was found that the membrane protein dissociates into electrophoretically and ultracentrifugally homogeneous subunits and thus it is inferred that the membrane protein of normal pteridine granules consists of a single homogeneous structural protein having a molecular weight of about 20, 000.
  • SANAE KAJI, MINORU ONCHI, MASANAO MICHINOMAE
    1976 年 51 巻 1 号 p. 53-58
    発行日: 1976年
    公開日: 2007/05/21
    ジャーナル フリー
    The effect of acetamide and certain antibiotics on the multiplication of the Ehrlich ascites tumor cells in mice was examined. The acetamide had a marked effect on increasing the mitotic rate of the EAT cells. However, mitomycin-C or nitromine had a strong inhibitory effect on the multiplication of the cells. In contrast the rate of cell multiplication in acetamide-mitomycin-C or nitromine mixture showed no effect what so ever. The acetamide appeared to counteract either mitomycin-C or nitromine on the metabolic process of the multiplication of EAT cell.
    The mode of the action on EAT cells by these two groups of chemicals was similar to that on the facet-formation in Drosophila. The acid amides not only are specific to the eye development in Drosophila, but also considerably increase the mitotic rate of EAT cells in the mouse.
  • HIKOYUKI YAMAGUCH, TADAO NAITO, ATSUSHI TATARA, ITSUO KUROBANE
    1976 年 51 巻 1 号 p. 59-60
    発行日: 1976年
    公開日: 2007/05/21
    ジャーナル フリー
  • 坂口 謙吾, 辻野 正俊, 水野 公男, 早野 和夫
    1976 年 51 巻 1 号 p. 61-64
    発行日: 1976年
    公開日: 2007/05/21
    ジャーナル フリー
    Bredinin, an effective inhibitor of nucleic acid synthesis, induced chromosome aberrations during the S and G2 phases of the mitotic cycle in L5178Y mouse leukemia cells. The maximum sensitivity to bredinin was during the latter half of S. The chromosome aberrations were prevented by simultaneous addition of guanylic acid and bredinin.
  • MAKOTO HAYASHI, YOSHIO OJIMA, NORIHIDE ASANO
    1976 年 51 巻 1 号 p. 65-68
    発行日: 1976年
    公開日: 2007/05/21
    ジャーナル フリー
    A procedure for the establishment of a cell line from the Gin-buna, Carassius auratus langsdorfii, is described. The cells of this line are characterized by quick growth, very high mitotic index and a highly qualified chromosome spreading. The utilization of the cell line in chromosome study of teleosts is suggested.
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