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Volume 60, Issue 1
Displaying 1-6 of 6 articles from this issue
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Junichi MIYAZAKI, Yeiko RYO, Teiichi MINAGAWA1985 Volume 60 Issue 1 Pages 1-9
Published: 1985
Released on J-STAGE: July 25, 2006
JOURNAL FREE ACCESSWe have previously shown that abnormally fast sedimenting DNA which accumulates upon infection of mutants of T4 phage defective in gene 49 is recombination intermediates, while the mutant gives rise to the recombination deficient phenotype, judging from genetic mating tests under the semipermissible condition (Minagawa and Ryo (1979) Mol, gen. Genet. 170: 113; Minagawa et al. (1983a) Virology 126:138; Miyazaki et al. (1983) Genetics 104:1). To see the step to which the recombination process has proceeded in the DNA, we investigated by the transfection assay whether the generation of contiguous recombinant strands is completed. Such strands were found to be formed normally or nearly normally in the absence of the gene 49 function, supporting the view that the gene product is involved in resolution of branched recombinational intermediates into linear duplexes.View full abstractDownload PDF (1019K) -
Keiko MURATA-MATSUBARA, Kuniharu OHNISHI, Kazuyoshi KIRITANI1985 Volume 60 Issue 1 Pages 11-25
Published: 1985
Released on J-STAGE: July 25, 2006
JOURNAL FREE ACCESSA mutation livS (livS1 in KA231) that occurred in a Salmonella typhimurium LT2 mutant strain CE5 (ilvC8 brnQ4) expressed pleiotropic effects on cellular characteristics. The mutation not only resulted in derepression of the transport of branched-chain amino acids (Ohnishi et al. 1980), but also altered the properties of the ribosome. Ribosomes of KA2313 (brnQ4 livS1), an Ilv+ transductant of KA231 from the wild-type donor, appeared to be more unstable than those of the ancestral strain KA204 (brnQ4) in a Tris-HCl buffer without MgCl2. When ribosomes of KA2313 were suspended in the buffer, they released substantial amounts of smaller proteins of less than 20, 000 daltons into the buffer, and ribonuclease I was activated. Ribosomes of KA204 liberated a little but much lesser amount of such proteins under the same condition, and ribonuclease I stayed in an inactive state. The livS gene was found to be closely linked to aroA located at 19min on the Salmonella genetic map. Co-transduction frequency of livS with aroA, and vice versa, ranged from 12 to 55%.View full abstractDownload PDF (1644K) -
Masashi TANAKA, Morimasa WADA, Hiraku ITIKAWA1985 Volume 60 Issue 1 Pages 27-38
Published: 1985
Released on J-STAGE: July 25, 2006
JOURNAL FREE ACCESSCellular DNA and RNA syntheses in the strains carrying a mutation in relA gene in combination with a mutation in either dnaK or dnaJ gene were examined. RNA synthesis was relaxed in either combination both in the presence and in the absence of an exess amount of L-valine. However, DNA syntheses remained inhibited under the same conditions, suggesting that the thermosensitive DNA synthesis and RNA synthesis which are coexhibited in the dnaK(Ts) and dnaJ(Ts) mutants are not directly related each other. Thus the relaxed RNA synthesis in the double mutants did not reflect on the restoration of their thermoresistant DNA synthesis.View full abstractDownload PDF (1205K) -
Katsumi NISHIKAWA, Homare KUWANA1985 Volume 60 Issue 1 Pages 39-52
Published: 1985
Released on J-STAGE: July 25, 2006
JOURNAL FREE ACCESSBoth of the two ace-7 strains of Neurospora crassa isolated in this laboratory lack the activity of glucose-6-phosphate dehydrogenase (G6PDH). In starvation culture for acetate, mycelium of ace-7 shows decreased level of NADPH as compared with that of other acetate mutant does. Two NADPH-forming enzymes, malate dehydrogenase (oxaloacetate-decarboxylating) (NADP+) (so called NADP-linked malic enzyme) and isocitrate dehydrogenase (NADP+), are induced by acetate added in culture medium. Acetate seems to make the ace-7 strain grow because it increases the concentration of NADPH by inducing NADPH-forming malic enzyme and isocitrate dehydrogenase. From ace-7 strains, two revertants were obtained which were derived by back mutation on the ace-7 gene and produce qualitatively different G6PDH from the wild type enzyme. This suggests that the ace-7 gene is a structural gene for G6PDH, in addition to the three structural genes proposed by Scott and Tatum (1970).View full abstractDownload PDF (1246K) -
Shin-ichi SATO1985 Volume 60 Issue 1 Pages 53-61
Published: 1985
Released on J-STAGE: July 25, 2006
JOURNAL FREE ACCESSThe embryo sac formation of Hemerocallis middendorffii var. esculenta (Koidz.) Ohwi proceeds in the manner of Polygonum type classified by Maheshwari (1950). The cytochemical characteristics of the mature embryo sac were as follows: The antipodal nuclei have thick thread-like chromatin deeply stained with methylgreen and Feulgen reaction. Other nuclei consisted of fine chromatin which shows faint pyroninophilia and very weak Feulgen reaction. This fact suggests that the antipodal nuclei are of a polytene nature or polyploidy. The cytoplasm of the antipodal cells contained some bodies which, like the nucleolus, revealed dense pyroninophilia and were strongly positive to the protein reaction. Consequently, these bodies are called "nucleolus-like bodies" (NLBs) in the present study. Considering that the antipodal cells have a rich cytoplasm and many NLBs, it is inferred that they play an important role in the embryo sac development. The egg cell had a number of starch grains around the nucleus, and the filiform apparatus, having grown sufficently at the micropylar end of synergids, was strongly positive to both PAS reaction and methylgreen.View full abstractDownload PDF (1498K) -
Kazuhiko KOSUDA1985 Volume 60 Issue 1 Pages 63-70
Published: 1985
Released on J-STAGE: July 25, 2006
JOURNAL FREE ACCESSThe epistatic interaction between the second and third chromosomes of D. melanogaster was quantified in male mating activity under no competition among males. The mean mating activity of the two-chromosome homozygote was 0.517±0.064. The expected value under a multiplicative model was 0.509±0.054. Coefficient of interaction, I, was calculated to be 0.008±0.129. k statistic, a new measure of epistasis devised by Seager and Ayala (1982), was 0.029±0.027, which is not significantly different from zero. It is concluded that there is no interchromosomal interaction between two major autosomes in male mating activity.View full abstractDownload PDF (847K)
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