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Volume 61 (1986)
- Issue 6 Pages 537-
- Issue 5 Pages 419-
- Issue 4 Pages 295-
- Issue 3 Pages 193-
- Issue 2 Pages 97-
- Issue 1 Pages 1-
Volume 61, Issue 5
Displaying 1-10 of 10 articles from this issue
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Hiroshi MOMOTA, Masatoshi ENOMOTO1986 Volume 61 Issue 5 Pages 419-436
Published: 1986
Released on J-STAGE: July 25, 2006
JOURNAL FREE ACCESSRates of flagellar- and P1 infective-phase variation, caused by reversible inversion of an H(=PD) and a C segment, respectively, were examined with strains having the three site-specific recombinase genes, hin+, pin+, and cin+, in every possible combination. The variation rates were compared in terms of gene functions on the assumptions that the three genes are similar in gene dosage and comparable with one another in the amount of gene products and that each rate reflects an activity of a single gene or genes combined. The three genes were arranged in the order of the variation rate they caused; cin+> hin+> pin+ for both directions of H inversion, cin+>> hin+>pin for C(+) inversion, and cin+>>pin+> hin+ for C(-) inversion. For C inversion the rates in a cin+ strain were higher than those in hin+ and pin+ by two or three orders of magnitude. It was suggested that for H inversion two couples of the genes, hin+ and pin+ and pin+ and cin+, function together, but hin+ and cin+ interact against each other and that for C inversion hin+ and pin+ interact synergistically, but function against cin+. The variation of P1 cin+ reached equilibrium at a ratio of C(+)/C(-)=6.1/3.9 in the four kinds of lysogenic strains, and the generations bringing about the equilibrium ranged from 16 to 36 depending on the host gene(s) that function against cin+View full abstractDownload PDF (1993K) -
III. Random separation of two types of chloroplast genomes in a hybrid callusShinji AKADA, Atsushi HIRAI1986 Volume 61 Issue 5 Pages 437-445
Published: 1986
Released on J-STAGE: July 25, 2006
JOURNAL FREE ACCESSIn the parasexual hybrid callus between Nicotiana glauca and N. langsdorfii, the two parental types of chloroplasts separate during callus development. The system to investigate the mode of separation involves the hormone independent growth of the hybrid callus between N. glauca and N. langsdorfii as a selective marker for the parasexal hybrid and the isoelectrofocusing patterns of the large subunit (LS) of Fraction I protein as a chloroplast genetic marker. We improved this system by utilizing N. gossei as a chloroplast donor, because the isoelectrofocusing patterns of LS from N. gossei and that from N. langsdorfii can be distinguished clearly. The hormone independency which is suitable for selecting hybrids in the state of small calli was restored by transmitting the nuclear genome of N. glauca into N. gossei by means of sexual hybridization. Using the improved system, the mode of chloroplast separation was investigated in more detail. It was found that 84% of the cells in a two month old parasexual hybrid callus have only one or the other parental type of chloroplasts and 16% of the cells have two types.
We calculated the rate of separation using the formulae based on the assumption that the two types of chloroplasts separate at random by cell divisions in the callus. The result obtained by the calculation turned out to be consistent to the experimental data obtained by the analysis of the two month old parasexual hybrid callus, showing that our assumption is reasonable.View full abstractDownload PDF (1335K) -
Malcolm FITZ-EARLE, Bungo SAKAGUCHI1986 Volume 61 Issue 5 Pages 447-460
Published: 1986
Released on J-STAGE: July 25, 2006
JOURNAL FREE ACCESSThe possible role of cytoplasmic sex ratio (SR) distortion in insect population control has been assessed experimentally. In Drosophila melanogaster the agent responsible for SR distortion is a male-killing spiroplasma and SR strains are characterized by females producing daughters but few, if any, sons. Populations were constructed of wildtype and SR females (of various male-kill effectivenesses) plus males, in different proportions. The frequency of females in the populations was monitored regularly. Under some circumstances the frequency of females increased but not to fixation or population collapse. In most instances the frequency of females declined (to as low as 25% in some cases), then went through cycles of increase and decrease, with gradually reduced amplitude over time. This pattern of fluctuations was repeatable over cages.
Independently, it was shown that SR females persisted in the cages for the length of the experiments. The unexpected extremely low frequencies of females found in cages established with an excess of females, raised the possibility of distorting a population by SR releases, and then when the female frequency is at its lowest point to add sterile male or similar load inducers to suppress the population. The possible role of density dependence is discussed.View full abstractDownload PDF (1593K) -
Tadashi INOUE, Otoya SUZUKI, Tsuneo KADA, Taro FUJII1986 Volume 61 Issue 5 Pages 461-467
Published: 1986
Released on J-STAGE: July 25, 2006
JOURNAL FREE ACCESSL-ethionine, a hepatocarcinogen, exhibited a strong bio-antimutagenic effect against spontaneous mutation in Ames' Salmonella strains as well as in a Bacillus subtilis mutator strain whose mutator activity was due to an error-prone DNA replicating enzyme. The bio-antimutagenic effect of L-ethionine was completely abolished by the presence of L-methionine, but not by D-methionine, suggesting that genetic effect of L-ethionine was expressed through its interaction with L-methionine metabolism in the treated cells.View full abstractDownload PDF (623K) -
II. Morphological variationMasayoshi WATADA, Shigeru OHBA, Yoshiko N. TOBARI1986 Volume 61 Issue 5 Pages 469-480
Published: 1986
Released on J-STAGE: July 25, 2006
JOURNAL FREE ACCESSGeographical variation in ten quantitative morphological characters in each sex were studied for seven sympatric populations of D. simulans and D. melanogaster, the former has recently colonized the main islands of Japan. Populations of D, melanogaster showed geographical variation in most of the characters studied (wing size, body weight, thorax length, eye size, ovariole number, and ratio of eye width and wing length). In D. simulans, geographical differentiation was found only in three characters, among which the ovariole number increased with the latitude as was seen in D. melanogaster. Ovariole number was positively correlated with fecundity. Morphological characters appear to be differentiated at various speeds among geographical populations according to their adaptive significance. In both species, Ogasawara population was strikingly different from the other six populations in characters relating body size and eye size. Eye size and ovariole number were highly correlated with body size in D, simulans, but not in D. melanogaster.View full abstractDownload PDF (940K) -
Kenichi AOKI1986 Volume 61 Issue 5 Pages 481-490
Published: 1986
Released on J-STAGE: July 25, 2006
JOURNAL FREE ACCESSA basic model of group selection was formulated by Eshel (1972) and corrected for an "unnatural" assumption by Roughgarden (1979). The model assumes two counteracting selective forces, i.e, group selection and individual selection, in a deme-structured population; and was proposed in relation to the evolution of altruistic behavior. In this paper, I derive further properties of this model, concentrating on the special case of two haploid individuals per deme. Specifically, I prove the existence and stability of polymorphic equilibria in the extreme case of migration rate 1. The existence and stability of other equilibria are studied systematically by defining four regions in the (m, k)-parameter space for fixed s. Here, k is a measure of group selection, s is the selection coefficient against the individually deleterious type, and m is the migration rate. One region appears to correspond to stable polymorphic equilibria. The results are discussed in relation to the critical equality k=2Nms where N is the deme size (Aoki, 1982), and also in relation to polymorphic equilibria in the diffusion approximation when mutation is ignored (Kimura, 1983, 1984; Ogura and Shimakura, submitted).View full abstractDownload PDF (876K) -
Michiyuki ONO, Hiroyuki HASHIMOTO, Masaharu YOSHIOKA, Hiroshi HARADA, ...1986 Volume 61 Issue 5 Pages 491-501
Published: 1986
Released on J-STAGE: July 25, 2006
JOURNAL FREE ACCESSThe vector possessing two marker genes encoding for, aminoglycoside phosphotransferase II (APH(3′)II) and nopaline synthase (NOS) was inserted into the octopine-type Ti plasmid through homologous recombination. Following the confirmation of foreign gene expression in Nicotiana glauca tumor cells with respect to kanamycin resistance and nopaline synthesis, the analysis was made on the transcripts. There was a quantitative difference in the amount of mRNA between APH(3′)II and NOS. The size of mRNA for APH(3′)II and NOS were 1250 bases and 1550 bases, respectively.View full abstractDownload PDF (2561K) -
Kiyoko ONIWA, Masao KIMURA1986 Volume 61 Issue 5 Pages 503-514
Published: 1986
Released on J-STAGE: July 25, 2006
JOURNAL FREE ACCESSSix species of the fresh water snail were collected from a total of 29 sampling sites. To evaluate genetic variability within and between populations, enzymes coded for by 18 presumed loci were examined by starch gel electrophoresis.
Out of the six species, three (S. niponica, S. multigranosa and S. nakasekoae) were endemic to the Lake Biwa and remaining three (S. libertine, S. reiniana and S. kurodai) were the snail species widely distributed throughout Japan. The proportion of polymorphic loci and the expected average heterozygosity per individual for the three endemic species were 0.120±0.069 and 0.019±0.003, respectively. Those for the three widespread species were 0.179±0.068 and 0.058±0.017 (mean±S.D.), respectively. The present result showed that the S. kurodai, which has been considered to be transitional between the S. libertine and S, niponica complexes (Davis, 1969), should be classified into the Davis′s S. libertina complex.View full abstractDownload PDF (936K) -
IV. The nucleotide sequence of pHY300PLK and some properties in relation to transformationHiromi ISHIWA, Harue SHIBAHARA-SONE1986 Volume 61 Issue 5 Pages 515-528
Published: 1986
Released on J-STAGE: July 25, 2006
JOURNAL FREE ACCESSThe whole nucleotide sequence of pHY300PLK (Ishiwa and Shibahara 1985a) has been determined, pHY300PLK consists of 4870 bp and contains an RNA primer for ori-177 and three open reading frames corresponding to TcR, ApR and Rep-α1. Twenty-three unique restriction endonuclease recognition sites were found. We have confirmed that ORF α1 of pHY300PLK is the plasmid replication gene. A rescue phenomenon has been found with respect to multiple infection by pHY300.2PLK (rep-) and pUB110. A series of experiments indicated that the oligomer form, pHY300.2PLK, was rescued by the monomeric form, pUB110. Additionally, some useful information for using pHY300PLK as a shuttle vector in molecular cloning studies is presented. (Key words: shuttle vector; E, coli; B, subtilis; tetracycline; ampicillin; kanamycin; rescue; MIC).View full abstractDownload PDF (1480K) -
Junpei ISHIGURO, Masami HAYASHI1986 Volume 61 Issue 5 Pages 529-531
Published: 1986
Released on J-STAGE: July 25, 2006
JOURNAL FREE ACCESSGenetic mapping of blasticidin S-resistant gene, bls 2, was made by tetrad analysis in the yeast S, cerevisiae. The bls 2 locus was placed between met 1 and MAL 4 loci located on the right arm of chromosome XI. The map distances calculated with a equation by Perkins were 12.1cM from MAL 4 and 21.3cM from met 1.View full abstractDownload PDF (232K)
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