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141.
Satoru Oka 《Bioscience, biotechnology, and biochemistry》2013,77(8):520-525
The bacterial growth is inhibited by nitrofurane compounds, although the yeast growth is hardly affected. In relation to the selective toxicity of nitrofuranes for bacteria, the interaction between microbes (Escherichia coli, Staphylococcus aureus and bakers– yeast) and nitrofurane compounds (5-nitro-2-furfural semicarbazone and 5-nitro-2-furylacryl amide) was examined.Apparently, in the bacterial suspension containing energy substrate, nitrofuranes are continuously reduced to corresponding aminofuranes, respectively. The velocity of the bacterial reduction at the growth inhibiting condition was evaluated as great as above 30 per cent of the limit of supplying velocity of coenzymes in the cell, the reduction velocity of such value is enough to inhibit the bacterial growth, because the electron transfer in the cell metabolism is disordered.On the other hand, in the yeast suspension, the reduction velocity was negligibly small. The difference of the reduction ability between bacteria and yeast was seemingly owing to the fact that the permeability of the nitrofuranes differs by the kind of microbe so that it was concluded that the antimicrobial effect of nitrofuranes is limited by the permeability for the microbe cell. 相似文献
142.
Akio Ozaki Ryoichi Katsumata Tetsuo Oka Akira Furuya 《Bioscience, biotechnology, and biochemistry》2013,77(10):2925-2930
The chorismate mutase and prephenate dehydratase genes of phenylalanine producing Corynebacterium glutamicum K38, which is resistant to p-fluorophenylalanine and m-fluorophenylalanine, were cloned into plasmid pCE53 in C. glutamicum KY9456, which lacks chorismate mutase and prephenate dehydratase. One of the resultant plasmids, pCmB4, contained a 9.4kb BamHI DNA fragment inserted into the unique BamHl site of pCE53. Plasmid pCmB4 complemented a phenylalanine and tyrosine double auxotroph of C. glutamicum KY9456. Introduction of pCmB4 into C. glutamicum RRL5 resulted in an about ten times increase in chorismate mutase activity. C. glutamicum K38 carrying the plasmid accumulated 19.0mg/ml of phenylalanine (50% increase over the yield of K38). 相似文献
143.
Tamio Mizukami Morimasa Yagisawa Shin Kawahara Hiroshi Kase Tetsuo Oka Akira Furuya 《Bioscience, biotechnology, and biochemistry》2013,77(4):1015-1018
We previously constructed an l-threonine-producing strain of E. coli W, KY8280, which is an Ile+ revertant of KY8279 which requires l-methionine, a,£-diaminopimelic acid and l-isoleucine [H. Kase et al., Agric. Biol. Chem., 35, 2089 (1971)]. From KY8280, another l-threonine-hyperproducing strain, KY8366, was obtained as an α-amino-β-hydroxy valeric acid (AHV, a threonine analog)-resistant mutant. Enzymatic analysis revealed that KY8280 constitutively expressed 8-fold higher l-threonine-sensitive aspartokinase I activity than KY8279. In addition, KY8366 constitutively expressed 13-fold higher l-lysine-sensitive aspartokinase III activity than KY8280. Such elevated levels of aspartokinases may contribute to the hyperproduction of l-threonine by these mutant strains. KY8366 produced 28 mg/ml of l-threonine in a culture medium fed with 12% glucose. 相似文献
144.
145.
Shizuko Yamaguchi Tomoko Yoshikawa Shingo Ikeda Tsunehiko Ninomiya 《Bioscience, biotechnology, and biochemistry》2013,77(7):797-802
Taste effects of six newly synthesized ribonucleotide derivatives, i.e., disodium salts of 2-methyl-5′-inosinic acid · 6H2O, 2-ethyl-5′-inosinic acid · 1.5H2O, 2-N-methyl-5′-guanylic acid · 5.5H2O, 2-N-dimethyl-5′-guanylic acid · 2.5H2O, 2-methylthio-5′-inosinic acid · 6H2O and 2-ethylthio-5′-inosinic acid · 2H2O, were studied. Stimulus thresholds (detection thresholds) of these derivatives ranged from about 0.02 to 0.006 g/100ml. Flavor-enhancing activities of them were 2.3 to 8.0 times larger than that of disodium 5′-inosinate · 7.5H2O IMP) in the synergistic effect with monosodium glutamate. Furthermore, the quality of taste of all the derivatives was recognized to be the same kind to that of IMP. 相似文献
146.
Takaaki Kojima Jumpei Hata Hiroya Oka Kenta Hayashi Kiyotaka Hitomi Hideo Nakano 《Bioscience, biotechnology, and biochemistry》2013,77(11):1911-1921
ABSTRACTIn natural systems, various metabolic reactions are often spatially organized to increase enzyme activity and specificity. Thus, by spatially arranging enzyme molecules in synthetic systems to imitate these natural systems, it is possible to promote a high rate of enzymatic turnover. In this present study, a normal and mutant form of the scCro DNA-binding protein were shown to bind orthogonally to specific recognition sequences under appropriate conditions. Furthermore, these DNA-binding tags were used to establish an enzyme assay system based on the spatial arrangement of transglutaminase and its substrate at the molecular level. Together, the results of the present study suggest that the scCro-tag may be a powerful tool to facilitate the synthetic spatial arrangement of proteins on a DNA ligand. 相似文献
147.
Asuka Kamei Yuki Watanabe Fumika Shinozaki Akihito Yasuoka Takashi Kondo Tomoko Ishijima 《Bioscience, biotechnology, and biochemistry》2013,77(11):1893-1897
Effects of the administration of maple syrup extract (MSX) on hepatic gene expression were investigated in mice fed a high-fat diet. Gene annotation enrichment analysis based on gene ontology revealed some changes in the expression of genes related to lipid metabolism and the immune response in MSX-fed mice. Detailed analysis of these data indicated that MSX ingestion mitigates hepatic inflammation. 相似文献
148.
Nε-acetylation occurs on select lysine residues in α-crystallin of the human lens and alters its chaperone function. In this study, we investigated the effect of Nε-acetylation on advanced glycation end product (AGE) formation and consequences of the combined Nε-acetylation and AGE formation on the function of α-crystallin. Immunoprecipitation experiments revealed that Nε-acetylation of lysine residues and AGE formation co-occurs in both αA- and αB-crystallin of the human lens. Prior acetylation of αA- and αB-crystallin with acetic anhydride (Ac2O) before glycation with methylglyoxal (MGO) resulted in significant inhibition of the synthesis of two AGEs, hydroimidazolone (HI) and argpyrimidine. Similarly, synthesis of ascorbate-derived AGEs, pentosidine and Nε-carboxymethyl lysine (CML), was inhibited in both proteins by prior acetylation. In all cases, inhibition of AGE synthesis was positively related to the degree of acetylation. While prior acetylation further increased the chaperone activity of MGO-glycated αA-crystallin, it inhibited the loss of chaperone activity by ascorbate-glycation in both proteins. BioPORTER-mediated transfer of αA- and αB-crystallin into CHO cells resulted in significant protection against hyperthermia-induced apoptosis. This effect was enhanced in acetylated and MGO-modified αA- and αB-crystallin. Caspase-3 activity was reduced in α-crystallin transferred cells. Glycation of acetylated proteins with either MGO or ascorbate produced no significant change in the anti-apoptotic function. Collectively, these data demonstrate that lysine acetylation and AGE formation can occur concurrently in α-crystallin of human lens, and that lysine acetylation improves anti-apoptotic function of α-crystallin and prevents ascorbate-mediated loss of chaperone function. 相似文献
149.
Tomoko Igawa Yuki Yanagawa Shin-ya Miyagishima Toshiyuki Mori 《Journal of plant research》2013,126(3):387-394
Angiosperms have a unique sexual reproduction system called “double fertilization.” One sperm cell fertilizes the egg and another sperm cell fertilizes the central cell. To date, plant gamete membrane dynamics during fertilization has been poorly understood. To analyze this unrevealed gamete subcellular behavior, live cell imaging analyses of Arabidopsis double fertilization were performed. We produced female gamete membrane marker lines in which fluorescent proteins conjugated with PIP2a finely visualized egg cell and central cell surfaces. Using those lines together with a sperm cell membrane marker line expressing GCS1-GFP, the double fertilization process was observed. As a result, after gamete fusion, putative sperm plasma membrane GFP signals were occasionally detected on the egg cell surface adjacent to the central cell. In addition, time-lapse imaging revealed that GCS1-GFP signals entered both the egg cell and the central cell in parallel with the sperm cell movement toward the female gametes during double fertilization. These findings suggested that the gamete fusion process based on membrane dynamics was composed of (1) plasma membrane fusion on male and female gamete surfaces, (2) entry of sperm internal membrane components into the female gametes, and (3) plasmogamy. 相似文献
150.
Takakazu?OkaEmail author Yoshio?Kanemitsu Nobuyuki?Sudo Haruo?Hayashi Kae?Oka 《BioPsychoSocial medicine》2013,7(1):7