Bioscience, Biotechnology, and Biochemistry
Online ISSN : 1347-6947
Print ISSN : 0916-8451
Volume 70 , Issue 3
Showing 1-32 articles out of 32 articles from the selected issue
Reviews
  • Munehiko ASAYAMA
    2006 Volume 70 Issue 3 Pages 565-573
    Published: 2006
    Released: March 23, 2006
    JOURNALS FREE ACCESS
    Cyanobacteria (blue-green algae) are photosynthesizing organisms that can be used as a model for analyzing light-responsive gene expression. The regulatory system of the light-responsive psbA gene with cis-elements and trans-acting factors was studied at both transcriptional and post-transcriptional levels. Positive regulation comprises DNA curvatures (CIT and RIB), upstream elements (UPE and promoter), and a light-induced sigma factor (SigD) of RNA polymerase in transcription. On the other hand, negative regulation involves mRNA instability through an AU-box under darkness. This two-step process is a candidate for a novel mechanism regulating light-responsive gene expression.
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  • Jun OGAWA, Chee-Leong SOONG, Shigenobu KISHINO, Qing-Shan LI, Nobuyuki ...
    2006 Volume 70 Issue 3 Pages 574-582
    Published: 2006
    Released: March 23, 2006
    JOURNALS FREE ACCESS
    Bioprocesses, which involve biocatalysts for the production of useful compounds, are expected to become a leading player in green chemistry. The first step in bioprocess development is screening for useful biological reactions in the immense number of microorganisms with infinite diversity and versatility. This review introduces some examples of bioprocess development that started from process design stemming from the discovery of unique metabolic processes, reactions, and enzymes in microbial nucleic acid and lipid metabolisms.
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  • Hiroshi KAWAIDE
    2006 Volume 70 Issue 3 Pages 583-590
    Published: 2006
    Released: March 23, 2006
    JOURNALS FREE ACCESS
    The plant hormone, gibberellin (GA), regulates plant growth and development. It was first isolated as a superelongation-promoting diterpenoid from the fungus, Gibberella fujikuroi. G. fujikuroi uses different GA biosynthetic intermediates from those in plants to produce GA3. Another class of GA-producing fungus, Phaeosphaeria sp. L487, synthesizes GA1 by using the same intermediates as those in plants. A molecular analysis of GA biosynthesis in Phaeosphaeria sp. has revealed that diterpene cyclase and cytochrome P450 monooxygenases were involved in the plant-like biosynthesis of GA1. Fungal ent-kaurene synthase is a bifunctional cyclase. Subsequent oxidation steps are catalyzed by P450s, leading to biologically active GA1. GA biosynthesis in plants is divided into three steps involving soluble enzymes and membrane-bound cytochrome P450. The activation of plant GAs is catalyzed by soluble 2-oxoglutarate-dependent dioxygenases, which is in contrast to the catalysis of fungal GA biosynthesis. This difference suggests that the origin of fungal GA biosynthesis is evolutionally independent of that in plants.
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Analytical Chemistry Regular Paper
  • Seiya TSUJIMURA, Shinki KOJIMA, Kenji KANO, Tokuji IKEDA, Mika SATO, H ...
    2006 Volume 70 Issue 3 Pages 654-659
    Published: 2006
    Released: March 23, 2006
    JOURNALS FREE ACCESS
    A novel FAD-dependent glucose dehydrogenase (FAD-GDH) was found and its enzymatic property for glucose sensing was characterized. FAD-GDH oxidized glucose in the presence of some artificial electron acceptors, except for O2, and exhibited thermostability, high substrate specificity and a large Michaelis constant for glucose. FAD-GDH was applied to an amperometric glucose sensor with Fe(CN)63− as a soluble mediator. The use of a relatively high concentration of Fe(CN)63− resulted in a good linearity between the current response and the glucose concentration, taking into account a large Michaelis constant for Fe(CN)63−. The glucose sensor was completely insensitive to O2 and responded linearly to glucose up to 30 mM. Compared to glucose, the response to other saccharides was negligible. The sensor can be stored at room temperature in a desiccator for at least one month without any change in the response or activity.
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Organic Chemistry Regular Papers
Organic Chemistry Notes
Biochemistry & Molecular Biology Regular Papers
  • Akiko FUJITA, Nami GOTO-YAMAMOTO, Isao ARAMAKI, Katsumi HASHIZUME
    2006 Volume 70 Issue 3 Pages 632-638
    Published: 2006
    Released: March 23, 2006
    JOURNALS FREE ACCESS
    In order to investigate the control mechanism of flavonol biosynthesis of grapevine, we obtained five genomic sequences (FLS1 to FLS5) of putative flavonol synthase genes from Vitis vinifera cv. Cabernet Sauvignon. The mRNA of five FLSs accumulated in flower buds and flowers, while the mRNA of FLS2, FLS4, and FLS5 accumulated in small berry skins and then decreased toward veraison. At the ripening stage, the mRNA of only FLS4 and FLS5 accumulated again. This change in mRNA accumulation did not contradict the flavonol accumulation in the berry skins. Shading of the berries completely inhibited the increase in flavonol content and mRNA accumulation of FLS4, but did not affect the mRNA accumulation of FLS5. The effects of light and plant hormones on flavonol accumulation were different from those on anthocyanin accumulation. Thus flavonol biosynthesis appears to be under a different control system from that of anthocyanin biosynthesis.
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  • Tomoya YAMAGUCHI, Takami HAYASHI, Katsuhiro NAKAYAMA, Setsuo KOIKE
    2006 Volume 70 Issue 3 Pages 639-645
    Published: 2006
    Released: March 23, 2006
    JOURNALS FREE ACCESS
    The most chilling-sensitive stage of rice has been found to be at the onset of microspore release. The microsporocytes produce a wall of callose between the primary cell wall and the plasma membrane, and it has been shown that precise regulation of callose synthesis and degradation in anther is essential for fertile pollen formation. In this study, genes for 10 callose synthases in the rice genome were fully annotated and phylogenetically analyzed. Expression analysis of these genes showed that OsGSL5, an ortholog of microsporogenesis-related AtGSL2, was specifically expressed in anthers, and was notably downregulated by cooling treatment. Gene expression profiles of Rho-type small GTP-binding proteins in rice anther were also analyzed. The mechanisms of callose synthesis in rice pollen formation and its relationships with cool tolerance are discussed.
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  • Yasushi KAMISAKA, Naomi NODA, Nao TOMITA, Kazuyoshi KIMURA, Tsutomu KO ...
    2006 Volume 70 Issue 3 Pages 646-653
    Published: 2006
    Released: March 23, 2006
    JOURNALS FREE ACCESS
    Genes involved in lipid accumulation were identified in Saccharomyces cerevisiae using transposon insertion mutagenesis. Five ORFs, such as SNF2, IRA2, PRE9, PHO90, and SPT21 were found from the analysis of the insertion sites in transposon insertion mutants with higher lipid content. Since these ORFs are not directly involved in storage lipid biosynthesis, we speculate that they are involved in carbon fluxes into storage lipids in response to nutrient conditions. Lipid analysis of disruptants of these ORFs indicated that the Δsnf2, and Δira2 disruptants had significantly higher lipid content. Cultivation in a nitrogen-limited medium increased the lipid content in all disruptants, among which the Δpre9 disruptant was the most sensitive to nitrogen limitation. We then focused on the Δsnf2 disruptant due to its higher lipid content and its function as a regulator of phospholipid synthesis. Lipid class analysis indicated that triacylglycerol and free fatty acids contributed to the increase in total lipids of the Δsnf2 disruptant. The addition of exogenous fatty acids was not so effective at increasing the lipid content in the Δsnf2 disruptant as it was in the wild type. It should be noticed that exogenous free linoleic acid was much higher in the Δsnf2 disruptant than in the wild type, as in the case of endogenous free fatty acids. In addition, the incorporation of exogenous fatty acids into cells increased in the disruptant, suggesting that fatty acid transporters were regulated by SNF2. The results suggest that metabolic fluxes into storage lipids, which are activated in the Δsnf2 disruptant, is repressed by the incorporation of exogenous fatty acids. They provide new insight into the biosynthesis of storage lipids in yeast.
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  • SI SI HLA, Takuma KIKUTA, Makiko SAKKA, Tetsuya KIMURA, Kazuo SAKKA
    2006 Volume 70 Issue 3 Pages 667-671
    Published: 2006
    Released: March 23, 2006
    JOURNALS FREE ACCESS
    Clostridium stercorarium F-9 pectate lyase Pel9A is a modular enzyme composed of two hypothetical family-9 catalytic modules of the polysaccharide lyases, CM9-1 and CM9-2, in order from the N terminus. In this study, we constructed and characterized CM9-1 and CM9-2 polypeptides as rCM9-1 and rCM9-2 respectively. Both of them, like the full-length Pel9A, required the Ca2+ ion for their enzyme activities and showed high activity toward polygalacturonic acid but lower activity toward pectin. The specific activity of rCM9-2 was three times higher than that of rCM9-1 and rCM9-2 by itself efficiently catalyzed the depolymerization reaction of polygalacturonic acid into monosaccharide as the major product. It was found that rCM9-1 and rCM9-2 adsorbed to polygalacturonic acid and pectin on native affinity PAGE analysis, suggesting that they contain an independent carbohydrate-binding module separable from a catalytic module or consist of a catalytic module with a binding affinity for pectic substrates.
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  • Kazutaka TSURUHAMI, Shigeharu MORI, Satoshi AMARUME, Shigetaka SARUWAT ...
    2006 Volume 70 Issue 3 Pages 691-698
    Published: 2006
    Released: March 23, 2006
    JOURNALS FREE ACCESS
    p-Nitrophenyl and eugenyl β-primeveroside (6-O-β-D-xylopyranosyl-β-D-glucopyranoside) hydrolytic activity was found in culture filtrate from Penicillium multicolor IAM7153, and the enzyme was isolated. The enzyme was purified as a β-primeverosidase-like enzyme by precipitation with ammonium sulfate followed by successive chromatographies on Phenyl Sepharose, Mono Q, and β-galactosylamidine affinity columns. The molecular mass was estimated to be 50 kDa by SDS–PAGE and gel filtration. The purified enzyme was highly specific toward the substrate p-nitrophenyl β-primeveroside, which was cleaved in an endo-manner into primeverose and p-nitrophenol, but a series of β-primeveroside as aroma precursors were hydrolyzed only slightly as substrates for the enzyme. In analyses of its hydrolytic action and kinetics, the enzyme showed narrow substrate specificity with respect to the aglycon and glycon moieties of the diglycoside. We conclude that the present enzyme is a kind of β-diglycosidase rather than β-primeverosidase.
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Biochemistry & Molecular Biology Notes
Food & Nutrition Science Regular Papers
  • Kana JOO, Yasuko KATO
    2006 Volume 70 Issue 3 Pages 591-597
    Published: 2006
    Released: March 23, 2006
    JOURNALS FREE ACCESS
    We often eat heat-coagulated (H-C) food proteins, but there have been few studies on the allergenic activity of H-C proteins after digestion and absorption in vivo. To show that H-C protein is not an allergen after digestion, mice were used to investigate the digestion and absorption of the protein through the intestinal epithelium into portal blood employing immunoblotting and competitive inhibition ELISA. Ovalbumin (OVA) was used as the model protein, and H-C OVA was prepared by heating a 5% OVA solution for 15 min in boiling water. Antigenic OVA was not detected in the soluble fraction of gastrointestinal contents or the portal blood of mice administered H-C OVA. Also, voluntary physical activities, as an assessment of anaphylaxis, were monitored for 15 h using OVA sensitized mice. Compared to the voluntary physical activities of sensitized mice without any load, no decrease in activity was observed in the group administered H-C OVA, but a significant decrease in activity was found in the mice administered unheated OVA. These results strongly indicate that H-C OVA does not retain allergenic properties.
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  • Yuanxia SUN, Shigeru HAYAKAWA, Melin CHUAMANOCHAN, Machiko FUJIMOTO, A ...
    2006 Volume 70 Issue 3 Pages 598-605
    Published: 2006
    Released: March 23, 2006
    JOURNALS FREE ACCESS
    Nonenzymatic glycation between ovalbumin (OVA) and seven D-aldohexoses was carried out to study the chemical and antioxidant characteristics of sugar–protein complexes formed in the dry state at 55 °C and 65% relative humidity for 2 d through the Maillard reaction (MR). The effects of Maillard reaction products (MRPs) modified with different aldohexoses on radical scavenging, lipid oxidation, and tetrazolium salt (XTT) reducibility were investigated. The results showed that the degree of browning and aggregation and the tryptophan-related fluorescent intensity of glycated proteins displayed a noticeable difference that depended on the sugars used for modification. All the glycated proteins exhibited higher antioxidant activity as compared to a heated control and native OVA, and the antioxidant activity was well correlated with browning development. Furthermore, the order of antioxidant activities for the seven complexes was as follows: altrose/allose–OVAs > talose/galactose–OVAs > gulose–OVA > mannose/glucose–OVAs. This implies that sugar–protein complexes with two sugars known as epimers about C-2 showed a similar antioxidant capacity. From these results, the configuration of a hydroxyl (OH) group about position C-2 did not influence the advanced cross-linking reaction, but the configuration of OH groups about C-3 and C-4 might be very important for formation of MRPs and their antioxidant behaviors.
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  • Chiyoko KAMEUE, Takamitsu TSUKAHARA, Kazunari USHIDA
    2006 Volume 70 Issue 3 Pages 606-614
    Published: 2006
    Released: March 23, 2006
    JOURNALS FREE ACCESS
    Butyrate induces apoptosis of various cancer cell lines in a p53-independent manner and inhibits the proliferation of cancer cells. In a previous report, we reported a significant reduction in tumor incidence in rat colon as a result of dietary sodium gluconate (GNA). The stimulation of apoptosis through enhanced butyrate production in the large intestine was involved in the antitumorigenic effect of GNA. In the present study, a cDNA microarray analysis was performed to investigate the particular mechanism involved in the antitumorigenic effect of GNA. Some up-regulated genes suggested by microarray analysis were further evaluated using real-time PCR. A microarray revealed that GNA regulates the expression of retinoic acid receptor (RAR) and retinoid X receptor (RXR), and several genes known as the target of retinoids in cancer cells. In other words, the antitumorigenic effect of GNA may involve the regulation of the retinoid signaling pathway by butyrate in a retinoid-independent manner.
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  • Jin-Song HE, Norihiro AZUMA, Toshio HAGIWARA, Choemon KANNO
    2006 Volume 70 Issue 3 Pages 615-625
    Published: 2006
    Released: March 23, 2006
    JOURNALS FREE ACCESS
    The effects of sugars (xylose, arabinose, fucose, fructose, galactose, glucose, sorbitol, maltose, sucrose, and lactose; 0–20% w/v) on the properties of the pressure-induced gel from a whey protein isolate (20%, 800 MPa, 30 °C, 10 min) were studied. All the sugars decreased the hardness, breaking stress and water-holding capacity of the gel at the same concentration of 55.5 mM. Increasing the sugar content changed the microstructure of the gel from a honeycomb-like structure to a stranded structure, while the strand thickness was progressively reduced. These results suggest that sugars decreased the degree of intermolecular S–S bonding of proteins and non-covalent interaction, and restrained the phase separation during gelation under high pressure.
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  • Nobuyuki HAYASHI, Ronggang CHEN, Hidekazu IKEZAKI, Shinya YAMAGUCHI, D ...
    2006 Volume 70 Issue 3 Pages 626-631
    Published: 2006
    Released: March 23, 2006
    JOURNALS FREE ACCESS
    A practical method for universal evaluation of the astringency of green tea infusion by a taste sensor system was established. The use of EGCg aqueous solution as a standard enabled analysis with high accuracy and reproducibility. The sensor output was converted into taste-intensity on the basis of Weber’s and Weber-Fechner laws, which was named the “EITast” value (“EIT” and “ast” are abbreviations for “Estimated Intensity of Taste” and “astringency” respectively). It was clarified that green tea infusion is to be classified into eight grades on the EITast scale. Furthermore, the high correlation of the EITast value with the human gustatory sense and the high stability of the taste sensor were proved.
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  • Narumi FUJITA, Eriko TANAKA, Masatsune MURATA
    2006 Volume 70 Issue 3 Pages 672-676
    Published: 2006
    Released: March 23, 2006
    JOURNALS FREE ACCESS
    Stored cut lettuce gradually turns brown on the cut section after several days of storage, because cutting induces phenylalanine ammonia-lyase (PAL) activity, the biosynthesis of polyphenol is promoted, and the polyphenols are oxidized by polyphenol oxidase. In this study, we screened for inhibitors of PAL derived from fermented broths of microbes and from foods and found that a cinnamon extract definitely inhibited PLA of cut lettuce. An active component was isolated by chromatographic procedures and was identified as trans-cinnamaldehyde. Browning of cut lettuce immersed in a solution containing trans-cinnamaldehyde was definitely repressed.
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  • Misato KOBAYASHI, Tamio OHNO, Teruo KAWADA, Hiroshi IKEGAMI, Masahiko ...
    2006 Volume 70 Issue 3 Pages 677-683
    Published: 2006
    Released: March 23, 2006
    JOURNALS FREE ACCESS
    Adiponectin is thought to be an important mediator of insulin sensitivity and atherosclerosis. Using mouse 19 SMXA recombinant inbred (RI) strains, a powerful tool for analyzing multifactorial genetic traits, we found relationships between serum adiponectin levels and diabetes-related traits, body mass index, and serum lipid levels, and also determined the loci controlling serum adiponectin levels by quantitative trait loci (QTL) analysis. RI strains exhibited widely ranging serum adiponectin concentration distribution patterns and diabetes-related traits. The serum adiponectin concentration showed the strongest negative correlation with fasting serum insulin concentration, but negative correlations were also observed with serum triglycerides, cholesterol, and liver weight. In contrast, neither the body mass index nor the blood glucose concentration correlated with serum adiponectin levels. These results suggest that hypoadiponectinemia might be used as a predictor of insulin resistance. In addition, two suggestive QTLs for serum adiponectin concentration were detected on Chromosome (Chr) 7, and an A/J allele at these loci was associated with elevated serum adiponectin concentrations. Identification of genes responsible for regulating the serum adiponectin concentration might lead to the development of novel treatments for patients with diabetes concomitant with hypoadiponectinemia.
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Food & Nutrition Science Notes
Microbiology & Fermentation Technology Regular Papers
  • Mari ISHIGAMI, Youji NAKAGAWA, Masayuki HAYAKAWA, Yuzuru IIMURA
    2006 Volume 70 Issue 3 Pages 660-666
    Published: 2006
    Released: March 23, 2006
    JOURNALS FREE ACCESS
    Some strains of Saccharomyces cerevisiae form a biofilm called a “flor” on the surface of wine after ethanolic fermentation, but the molecular mechanism of flor formation by the wild-type flor strain involved in wine making is not clear. Previously, we found that expression of the C-terminally truncated form of NRG1 (NRG11-470) on a multicopy plasmid increases the hydrophobicity of the cell surface, conferring flor formation on the non-flor laboratory strain. Here we show that in Ar5-H12, a wild-type flor haploid strain, flor formation is regulated by NRG11-470. Moreover, the disruptant of the wild-type flor diploid strain (Δflo11flo11) show a weak ability to form the flor. The expression of FLO11 is always high in the wild-type flor strain, regardless of carbon source. Thus FLO11 is primary factor for wild-type flor strains. Furthermore, the disruptant (Δflo11) shows lower hydrophobicity of cell surface than the wild type. However, the hydrophobicity of the wild-type flor strains grown in ethanol medium was much higher than those grown in glucose medium. These results indicate that cell surface hydrophobicity is closely related to flor formation in wild-type flor yeasts.
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  • Taweesak MALIMAS, Pattaraporn YUKPHAN, Mai TAKAHASHI, Wanchern POTACHA ...
    2006 Volume 70 Issue 3 Pages 684-690
    Published: 2006
    Released: March 23, 2006
    JOURNALS FREE ACCESS
    Twenty-three strains, which were assigned to Gluconobacter frateurii and maintained at Culture Collection NBRC, were re-identified at the species level on the basis of restriction analysis of 16S-23S rDNA ITS regions by digestion with six restriction endonucleases: Bsp1286I, MboII, AvaII, TaqI, BsoBI, and BstNI. The strains examined were divided into six groups, Group III-1, Group III-2, Group III-3, Group III-4, Group III-5, and Group IV. Group III-1 and Group III-4 respectively were divided into two subgroups, Subgroup III-1a, Subgroup III-1b and Subgroup III-4a, Subgroup III-4b. Gluconobacter frateurii NBRC 3264T was included in Group III-2, along with strains NBRC 3265 and NBRC 3270, and G. thailandicus BCC 14116T was included in Group III-3, along with strains NBRC 3254, NBRC 3256, NBRC 3258, NBRC 3255, and NBRC 3257. These groupings were supported by a phylogenetic tree based on 16S-23S rDNA ITS sequences. Strains of group III-2 and Group IV were unequivocally re-identified as G. frateurii, but strains of Group III-3, Group III-4, and Group III-5 were not necessarily re-identified as G. frateurii. The results obtained indicate that the 23 strains have a taxonomically heterogeneous nature, and they are referred to as the G. frateurii complex.
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Microbiology & Fermentation Technology Notes
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