Bioscience, Biotechnology, and Biochemistry
Online ISSN : 1347-6947
Print ISSN : 0916-8451
Volume 75 , Issue 11
Showing 1-35 articles out of 35 articles from the selected issue
Analytical Chemistry Regular Paper
  • Lila OTANI, Shinya OGAWA, Zhilei ZHAO, Kyoko NAKAZAWA, Shunsuke UMEHAR ...
    2011 Volume 75 Issue 11 Pages 2119-2124
    Published: November 23, 2011
    Released: November 23, 2011
    [Advance publication] Released: November 07, 2011
    JOURNALS FREE ACCESS
    The analytical method was optimized for L-cysteine (Cys) in rat plasma with co-existing L-cystine (Cyss). We observed that more than 100% Cyss in rat plasma was converted to Cys under typical conditions for the conversion with 7-fluoro-2,1,3-benzoxadiazole-4-sulfonate (SBD-F). Another conversion reagent, 4-aminosulfonyl-7-fluoro-2,1,3-benzoxadiazole (ABD-F), was then employed, with which the reaction could be carried out at a low temperature without the use of a reducing reagent. Under the optimized conditions of 4 °C and pH 8.3, the conversion ratio of Cyss to Cys in rat plasma was as low as 5–7%. We determined the Cys concentration in plasma of the portal vein of rats that had been orally administered with Cys and Cyss by applying this method. The result indicated that Cys administration and also Cyss administration effectively increased the plasma Cys level. The method developed in this study is well suited for determining the thiol compounds in biological samples.
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Organic Chemistry Regular Papers
  • Ayako OSAWA, Asami KASAHARA, Shoko MASTUOKA, Sören GASSEL, Gerhar ...
    2011 Volume 75 Issue 11 Pages 2142-2147
    Published: November 23, 2011
    Released: November 23, 2011
    [Advance publication] Released: November 07, 2011
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    Supplementary material
    In the course of screening for antioxidative carotenoids from bacteria, we isolated and identified a novel carotenoid, OH-chlorobactene glucoside hexadecanoate (4), and rare carotenoids, OH-chlorobactene glucoside (1), OH-γ-carotene glucoside (2) and OH-4-keto-γ-carotene glucoside hexadecanoate (3) from Rhodococcus sp. CIP. The singlet oxygen (1O2) quenching model of these carotenoids showed potent antioxidative activities IC50 14.6 μM for OH-chlorobactene glucoside hexadecanoate (4), 6.5 μM for OH-chlorobactene glucoside (1), 9.9 μM for OH-γ-carotene glucoside (2) and 7.3 μM for OH-4-keto-γ-carotene glucoside hexadecanoate (3).
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  • Masayuki NINOMIYA, Hitoshi SATOH, Yuji YAMAGUCHI, Hiroyuki TAKENAKA, M ...
    2011 Volume 75 Issue 11 Pages 2175-2177
    Published: November 23, 2011
    Released: November 23, 2011
    [Advance publication] Released: November 07, 2011
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    The extract of terrestrial alga Nostoc commune Vauch. has high antioxidative activity. Our study on N. commune Vauch. resulted in the isolation of two β-ionone derivatives, nostocionone and 3-oxo-β-ionone, together with four indole alkaloids, scytonemin, reduced scytonemin, N-(p-coumaroyl)tryptamine, and N-acetyltryptamine. The structures of the isolated compounds were determined on the basis of 1D and 2D NMR and MS analyses. Among these isolates, nostocionone and reduced scytonemin demonstrated strong antioxidative activities which were assessed by using a β-carotene oxidation assay.
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  • Morio YOSHIMURA, Yoshiaki AMAKURA, Takashi YOSHIDA
    2011 Volume 75 Issue 11 Pages 2207-2212
    Published: November 23, 2011
    Released: November 23, 2011
    [Advance publication] Released: November 07, 2011
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    Two new polyphenolic glucosides, 6′-O-acetylisobiflorin (1) and (2S)-3-(4-hydroxy-3-methoxyphenyl)-propane-1,2-diol 1-O-(6′-O-galloyl)-β-D-glucoside (2), were respectively isolated from the flower buds of Syzygium aromaticum and berries of Pimenta dioica. Each structure was elucidated on the basis of spectral analyses (NMR, MS and [α]D) and chemical conversion. A total of twenty-seven known compounds from the plants were also characterized. The antioxidative activity of their extracts and the twenty-nine isolates including gallo- and ellagitannins was estimated by oxygen radical absorbance capacity (ORAC) assay, and eugenol (3), which was the most abundant ingredient in each plant extract, showed the most potent antioxidative activity [ORAC value of 39,270 μmol TE (trolox equivalent)/g].
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  • Tetsuya ISAKA, Morifumi HASEGAWA, Hiroaki TOSHIMA
    2011 Volume 75 Issue 11 Pages 2213-2222
    Published: November 23, 2011
    Released: November 23, 2011
    [Advance publication] Released: November 07, 2011
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    Cyclization of the synthesized epoxide precursors of indole mono-, sesqui- and diterpene alkaloids was performed to elucidate the mechanism for biomimetic cationic cyclization to polycyclic structures. 3-(6,7-Epoxygeranyl)indole (11), 3-(10,11-epoxyfarnesyl)indole (2) and 3-(14,15-epoxygeranylgeranyl)indole (3) were respectively synthesized from geraniol, farnesol and geranylgeraniol in 6 or 7 steps. Four Lewis acids (MeAlCl2, BF3·OEt2, TiCl4 and SnCl4) were applied for biomimetic cyclization of the synthesized epoxide precursors. The cyclization products (one product from 11, four products from 2, and three products from 3) were isolated after separation by chromatography. Their structures were determined by using NMR (COSY, HSQC, HMBC, NOESY, etc.) and HRMS analyses. The results show that biomimetic cyclization gave new polycyclic compounds similar to natural indole terpene alkaloids. We conclude that the stability of cation intermediates should determine the preference for product formation by biomimetic cyclization when using a Lewis acid.
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Organic Chemistry Notes
Biochemistry & Molecular Biology Regular Papers
  • Anthony Jide AFOLAYAN, Taofik Olatunde SUNMONU
    2011 Volume 75 Issue 11 Pages 2083-2086
    Published: November 23, 2011
    Released: November 23, 2011
    [Advance publication] Released: November 07, 2011
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    Diabetes is characterized by hyperglycemia resulting from defects in pancreatic insulin secretion and/or impaired target cell responsiveness to insulin, and Artemisia afra Jacq. is widely used in South Africa to treat the disease, but the mechanism of action is yet to be elucidated. This study explored the effect of oral administration of aqueous leaf extract of A. afra on the pancreas of streptozotocin-induced diabetic rats. We found that the extract significantly reduced blood glucose levels, accompanied by an increase in the serum insulin concentration. Moreover, the antioxidant enzymic activities of glutathione peroxidase, glutathione reductase, and superoxide dismutase also improved significantly after treatment with the extract. Increased pancreatic lipid peroxidation in the diabetic rats was also normalized by the extract. This study indicates that A. afra possesses hypoglycemic and antioxidant activities. Our findings suggest that the herb might exert its anti-diabetic activity by regenerating pancreatic beta cells, thereby stimulating the release of insulin.
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  • Takashi HOSHIBA, Naoki KAWAZOE, Guoping CHEN
    2011 Volume 75 Issue 11 Pages 2099-2104
    Published: November 23, 2011
    Released: November 23, 2011
    [Advance publication] Released: November 07, 2011
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    The mechanism of regulation of PPARG expression during the osteogenesis of human mesenchymal stem cells (MSCs) was investigated on an extracellular matrix (ECM) model that mimicked the stepwise osteogenesis ECM. Three matrices that mimicked the ECM of MSCs (stem cell matrices), the early stage ECM (early stage matrices), and the late stage ECM (late stage matrices) of osteogenesis were prepared and compared. The matrices showed different effects on the Wnt/β-catenin signal. The β-catenin signal was activated by endogenous Wnt through interaction with chondroitin sulfate chains to suppress PPARG expression on the stem cell matrices and early stage matrices but not on late stage matrices.
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  • Satoshi SEKIGUCHI, Kiyoshi YASUKAWA, Kuniyo INOUYE
    2011 Volume 75 Issue 11 Pages 2132-2137
    Published: November 23, 2011
    Released: November 23, 2011
    [Advance publication] Released: November 07, 2011
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    In this study, we evaluated the effects of polyethylene glycol (PEG) on bovine intestine alkaline phosphatase (BIALP) activity and stability. In the hydrolysis of p-nitrophenylphosphate (pNPP) at pH 9.8 at 20 °C, the kcatKm values of BIALP plus 5–15% w/v free PEG with molecular masses of 1, 2, 6, and 20 kDa (PEG1000, PEG2000, PEG6000, and PEG20000 respectively) were 120–140%, 180–300%, 130–170%, and 110–140% respectively of that of BIALP without free PEG (1.8 μM−1 s−1), indicating that activation by PEG2000 was the highest. Unmodified BIALP plus 5% PEG2000 and BIALP pegylated with 2,4-bis(O-methoxypolyethylene glycol)-6-chloro-s-triazine exhibited 1.3-fold higher activity on average than that of BIALP without free PEG under various conditions, including pH 7.0–10.0 and 20–65 °C. The temperatures reducing initial activity by 50% in 30-min incubation of unmodified BIALP plus 5% PEG2000 and pegylated BIALP were 51 and 47 °C respectively, similar to that of BIALP without free PEG (49 °C). These results indicate that the addition of PEG2000 and pegylation increase BIALP activity without affecting its stability, suggesting that they can be used in enzyme immunoassay with BIALP to increase sensitivity and rapidity.
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  • Hyun-ju IHN, Dong Hyeok KIM, Sang-Seok OH, Chaerin MOON, Jin Woong CHU ...
    2011 Volume 75 Issue 11 Pages 2138-2141
    Published: November 23, 2011
    Released: November 23, 2011
    [Advance publication] Released: November 07, 2011
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    IL-17-producing T lymphocytes have been found to comprise a distinct lineage of T helper cells (Th17 cells) that are major causes of autoimmune diseases such as EAE, RA, and IBD. In this study, we found that activin receptor type-2A (Acvr2a) is a gene induced during the differentiation of this effector cell lineage as compared with naïve T cells. The transcript of Acvr2a was not induced in Th1 and Th2 cells, and both TGF-β and IL-6 were required for the induction of Acvr2a. When the differentiation of Th17 cells was inhibited by all tarans retinoic acid (ATRA) which induces regulatory T cell (Treg) differentiation under Th17 differentiation conditions, expression of Acvr2a was also inhibited. Hence we propose that Acvr2a is a Th17 specific gene making Th17 cells distinct from other helper T cells, Th1, Th2, and Treg.
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  • Hanayo UEOKA-NAKANISHI, Nanako HORI, Kai ISHIDA, Natsuko ONO, Takafumi ...
    2011 Volume 75 Issue 11 Pages 2148-2154
    Published: November 23, 2011
    Released: November 23, 2011
    [Advance publication] Released: November 07, 2011
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    Sessile plants must continuously adjust their growth and development to optimize photosynthetic activity under ever-fluctuating light conditions. Among such light responses in plants, one of the best-characterized events is the so-called shade avoidance, for which a low ratio of the red (R):far-red (FR) light intensities is the most prominent stimulus. Such shade avoidance responses enable plants to overtop their neighbors, thereby enhancing fitness and competitiveness in their natural habitat. Considerable progress has been achieved during the last decade in understanding the molecular mechanisms underlying the shade avoidance responses in the model rosette plant, Arabidopsis thaliana. We characterize here the fundamental aspects of the shade avoidance responses in the model legume, Lotus japonicus, based on the fact that its phyllotaxis (or morphological architecture) is quite different from that of A. thaliana. It was found that L. japonicus displays the characteristic shade avoidance syndrome (SAS) under defined laboratory conditions (a low R:FR ratio, low light intensity, and low blue light intensity) that mimic the natural canopy. In particular, the outgrowth of axillary buds (i.e., both aerial and cotyledonary shoot branching) was severely inhibited in L. japonicus grown in the shade. These results are discussed with special emphasis on the unique aspects of SAS observed with this legume.
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  • Shigeru KAWANO, Miho YANO, Junzo HASEGAWA, Yoshihiko YASOHARA
    2011 Volume 75 Issue 11 Pages 2155-2161
    Published: November 23, 2011
    Released: November 23, 2011
    [Advance publication] Released: November 07, 2011
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    5-((R)-1-Hydroxyethyl)-furo[2,3-c]pyridine ((R)-FPH) is a useful chiral building block in the synthesis of pharmaceuticals. An NADH-dependent alcohol dehydrogenase (AFPDH) isolated from Candida maris catalyzed the reduction of 5-acetylfuro[2,3-c]pyridine (AFP) to (R)-FPH with 100% enantiomeric excess. The gene encoding AFPDH was cloned and sequenced. The AFPDH gene comprises 762 bp and encodes a polypeptide of 27,230 Da. The deduced amino acid sequence showed a high degree of similarity to those of other members of the short-chain alcohol dehydrogenase superfamily. The AFPDH gene was overexpressed in Escherichia coli under the control of the lac promoter. One L of the cultured broth of an E. coli transformant coexpressing AFPDH and the glucose dehydrogenase (GDH) gene reduced 250 g of AFP to (R)-FPH in an organic solvent two-phase system. Under coupling with NADH regeneration using 2-propanol, 1 L of the cultured broth of an E. coli transformant expressing the AFPDH gene reduced 150 g of AFP to (R)-FPH. The optical purity of the (R)-FPH formed was 100% enantiomeric excess under both reaction conditions.
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  • Teruyo OJIMA, Wataru SABURI, Hiroki SATO, Takeshi YAMAMOTO, Haruhide M ...
    2011 Volume 75 Issue 11 Pages 2162-2168
    Published: November 23, 2011
    Released: November 23, 2011
    [Advance publication] Released: November 07, 2011
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    Supplementary material
    Cellobiose 2-epimerase (CE) reversibly converts glucose residue to mannose residue at the reducing end of β-1,4-linked oligosaccharides. It efficiently produces epilactose carrying prebiotic properties from lactose, but the utilization of known CEs is limited due to thermolability. We focused on thermoholophilic Rhodothermus marinus JCM9785 as a CE producer, since a CE-like gene was found in the genome of R. marinus DSM4252. CE activity was detected in the cell extract of R. marinus JCM9785. The deduced amino acid sequence of the CE gene from R. marinus JCM9785 (RmCE) was 94.2% identical to that from R. marinus DSM4252. The N-terminal amino acid sequence and tryptic peptide masses of the native enzyme matched those of RmCE. The recombinant RmCE was most active at 80 °C at pH 6.3, and stable in a range of pH 3.2–10.8 and below 80 °C. In contrast to other CEs, RmCE demonstrated higher preference for lactose over cellobiose.
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  • Shumpei ASAMIZU, Yoshitsugu SHIRO, Yasuhiro IGARASHI, Shingo NAGANO, H ...
    2011 Volume 75 Issue 11 Pages 2184-2193
    Published: November 23, 2011
    Released: November 23, 2011
    [Advance publication] Released: November 07, 2011
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    The diversity of indolocarbazole natural products results from the differences in oxidation states of the pyrroline ring moiety. In the biosynthetic pathways for staurosporine and rebeccamycin, two homologous enzymes having 64% identity, StaC and RebC, are responsible for the selective production of K252c, which has one oxo group at the pyrroline ring, and arcyriaflavin A, which has two. Although StaC has a FAD-binding motif, most StaC molecules do not contain FAD, and the protein cannot be reconstituted with FAD in vitro. In this study, we mutated Ala-118 in StaC by replacing a glutamine that is conserved in FAD monooxygenases, resulting in increased FAD content as well as catalytic activity. In addition, mutations around the substrate-binding sites of StaC and RebC can change the product selectivity. Specifically, StaC-N244R-V246T and RebC-F216V-R239N mutants produced substantial amounts of arcyriaflavin A and K252c, respectively.
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  • Qingshi MENG, Liqun RAO, Xiaocong XIANG, Chunxi ZHOU, Xinyi ZHANG, Yin ...
    2011 Volume 75 Issue 11 Pages 2194-2199
    Published: November 23, 2011
    Released: November 23, 2011
    [Advance publication] Released: November 07, 2011
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    Supplementary material
    A systematic strategy was developed for the proteomic analysis of wheat chloroplast protein complexes. First, comprehensive centrifugation methods were utilized for the exhaustive isolation of thylakoid, envelope, and stromal fractions. Second, 1% n-dodecyl-β-D-maltoside was selected from a series of detergents as the optimal detergent to dissolve protein complexes effectively from membranes. Then, blue native polyacrylamide gel electrophoresis (BN–PAGE) and sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS–PAGE) were improved to separate and analyze the protein complexes. By this systematic strategy, envelopes, thylakoids, and stromata were enriched effectively from chloroplasts in the same process, and more than 18 complexes were obtained simultaneously by BN–PAGE. Finally, thylakoid protein complexes were further analyzed by BN/SDS–PAGE, and nine complex bands and 40 protein spots were observed on BN–PAGE and SDS–PAGE respectively. Our results indicate that this new strategy can be used efficiently to analyze the proteome of chloroplast protein complexes and can be applied conveniently to the analysis of other subcellular protein complexes.
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  • Kwanchanok SATTASUK, Akira NOZAWA, Yuzuru TOZAWA, Yoshimi KAKINUMA, Mi ...
    2011 Volume 75 Issue 11 Pages 2200-2206
    Published: November 23, 2011
    Released: November 23, 2011
    [Advance publication] Released: November 07, 2011
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    We identified a gene product of At5g19500 (At5g19500p) from Arabidopsis thaliana that is homologous to EcTyrP, a tyrosine-specific transporter from Escherichia coli. Computational analyses of the amino acid sequence of At5g19500p predicted 11 transmembrane domains (TMDs) and a potential plastid targeting signal at its amino terminus. As a first step toward understanding the possible role of At5g19500p in plant cells, we attempted to determine the localization of At5g19500p by an in vitro chloroplastic import assay using At5g19500p translated in a cell-free wheat germ system (Madin et al., Proc. Natl. Acad. Sci. USA, 97, 559–564 (2000)), followed by subfractionation of the chloroplasts. At5g19500p was successfully imported into chloroplasts, and the newly transported mature form of At5g19500p was recovered from the inner envelope membrane.
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Food & Nutrition Science Regular Papers
  • Atsuko SAGAWA, Naoki KOBAYASHI, Hatsue MORITAKA
    2011 Volume 75 Issue 11 Pages 2105-2111
    Published: November 23, 2011
    Released: November 23, 2011
    [Advance publication] Released: November 07, 2011
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    The influence of food thickeners (potato starch, guar gum, and xanthan gum and deionized water) on the breakdown of solid food was numerically analyzed, and an investigation was made into the cumulative size distribution of food fragments, textural properties, sensory evaluation and maximum transit velocity of a bolus in the pharynx.
    The results suggest that evaluating the breakability into small pieces was easily influenced by the addition ratio of the dispersion medium. However, in respect of the destruction process for the solid body, each sample was more strongly affected by the type of the dispersion medium than by the addition ratio of this medium.
    The destruction process was strongly influenced by the history of the breakdown caused by mastication when a liquid dispersion medium was added to the solid. However, when a high-viscosity sol was added to the solid, the destruction process was random and not affected by any history.
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  • Mito KOKAWA, Kaori FUJITA, Junichi SUGIYAMA, Mizuki TSUTA, Mario SHIBA ...
    2011 Volume 75 Issue 11 Pages 2112-2118
    Published: November 23, 2011
    Released: November 23, 2011
    [Advance publication] Released: November 07, 2011
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    A novel method combining imaging techniques and fluorescence fingerprint (FF) data measurement was developed to visualize the distributions of gluten and starch in dough without any preprocessing. Fluorescence images of thin sections of gluten, starch, and dough were acquired under 63 different combinations of excitation and emission wavelengths, resulting in a set of data consisting of the FF data for each pixel. Cosine similarity values between the FF of each pixel in the dough and those of gluten and starch were calculated. Each pixel was colored according to the cosine similarity value to obtain a pseudo-color image showing the distributions of gluten and starch. The dough sample was then fluorescently stained for gluten and starch. The stained image showed patterns similar to the pseudo-color FF image, validating the effectiveness of the FF imaging method. The method proved to be a powerful visualization tool, applicable in fields other than food technology.
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  • Masataka NARUKAWA, Kanako MORITA, Masahide UEMURA, Ryo KITADA, Seong-H ...
    2011 Volume 75 Issue 11 Pages 2125-2131
    Published: November 23, 2011
    Released: November 23, 2011
    [Advance publication] Released: November 07, 2011
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    Food contains various taste substances. Among them, umami substances play an important role with regard to the perception of the taste of food, but, few studies have examined the taste characteristics of representative umami substances other than monosodium L-glutamate (MSG). By conducting mouse behavioral studies (the 48-h 2-bottle preference test and the conditioned taste aversion test) and assessing gustatory nerve responses, we investigated the taste characteristics of unique umami substances, including sodium succinate, L-theanine, betaine, and the enantiomer of MSG, D-MSG. Furthermore, we examined the synergy of umami with inosine 5′-monophoshate (IMP). In the case of the mice, sodium succinate had an umami taste and showed strong synergy with IMP. L-Theanine showed synergy with IMP but did not have an umami taste without IMP. In contrast, betaine did not have an umami taste or synergy with IMP. D-MSG might have weak synergy with IMP.
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  • Shingo HINO, Hiroyuki ITO, Hiroyuki BITO, Hirokazu KAWAGISHI, Tatsuya ...
    2011 Volume 75 Issue 11 Pages 2169-2174
    Published: November 23, 2011
    Released: November 23, 2011
    [Advance publication] Released: November 07, 2011
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    We evaluated the ameliorating effects of short-chain inulin-like fructans (SIF) with different degrees of polymerization (DP) on the healing stage of trinitrobenzene sulfonic acid (TNBS)-induced colitis in rats. The rats were assigned to 3 groups 10 d after the colitis induction, and fed for 24 d on a control diet or diet including 60 g of DP4 or DP8/kg. The fecal myeloperoxidase (MPO) activity and IgA concentration were monitored every 7 d. The colonic MPO activities and cecal concentrations of organic acids, lactobacilli, bifidobacteria, mucin and IgA were measured at the end of the study. DP4, but not DP8, significantly reduced the colonic inflammation accompanied by higher cecal concentrations of short-chain fatty acids, propionate in particular, and lactic acid-producing bacteria. DP4 therefore accelerated the healing process of TNBS-induced colitis, even when the treatment was initiated after inducing colitis.
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  • Huimin YAN, Shigeru KAKUTA, Masao NISHIHARA, Masahito SUGI, Yoshiyuki ...
    2011 Volume 75 Issue 11 Pages 2178-2183
    Published: November 23, 2011
    Released: November 23, 2011
    [Advance publication] Released: November 07, 2011
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    Kjellmaniella crassifolia Miyabe (gagome) is a brown alga. Oral gagome administration (oral gagome) resulted in significant upregulation of IL-10 and IFNγ production by Peyer’s patch cells. To assess the adjuvant activity of oral gagome, treated mice were subcutaneously injected with ovalbumin (OVA). The production of cytokines from antigen (Ag)-specific T cells in draining lymph nodes (dLN) and their proliferative response were significantly increased as compared with the control group. These enhancements were associated with increased CD44hiCD62L activated/memory T cells in dLN as well as upregulation of Ag-specific IgA level in luminal contents. No upregulation of cytokine production by dLN T cells was observed in dectin-1-deficient mice, suggesting that the effect of gagome on cytokine production is largely dependent on the dectin-1 pathway despite its composite constituents. Our findings indicate that gagome is an effective immunomodulator and a potent adjuvant for both the intestinal and the systemic immune response.
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  • Ji Young YEO, Tae Joung HA, Jeong-Su NAM, Myeong-Ho JUNG
    2011 Volume 75 Issue 11 Pages 2223-2228
    Published: November 23, 2011
    Released: November 23, 2011
    [Advance publication] Released: November 07, 2011
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    The inhibitory activity of Vigna nakashimae extract against intestinal α-glucosidase was investigated in vitro and in vivo. The extract exerted a significant inhibitory effect against intestinal α-glucosidases. With sucrose-loading, it reduced the peak responses of blood glucose significantly in normal mice. Next, it was administrated to 8-week-old db/db mice for 2 weeks, and then plasma glucose, triglyceride, and total cholesterol levels were measured. The extract significantly suppressed postprandial hyperglycemia and blood glycated hemoglobin in the db/db mice. In addition, it lowered fasting glucose and improved glucose tolerance. Furthermore, it led to significant decreases in plasma triglyceride levels. It reduced endoplasmic reticulum stress in thapsigargin-induced HepG2 cells. Taken together, these results suggest that Vigna nakashimae extract has hypoglycemic and hypolipidemic effects that occur via inhibition of α-glucosidase activity and endoplasmic reticulum stress.
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Food & Nutrition Science Notes
Microbiology & Fermentation Technology Regular Papers
  • Isao ABE, Seiichi HARA, Kenzo YOKOZEKI
    2011 Volume 75 Issue 11 Pages 2087-2092
    Published: November 23, 2011
    Released: November 23, 2011
    [Advance publication] Released: November 07, 2011
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    The gene encoding α-amino acid ester acyl transferase (AET), the enzyme that catalyzes the peptide-forming reaction from amino acid methyl esters and amino acids, was cloned from Empedobacter brevis ATCC14234 and Sphingobacterium siyangensis AJ2458 and expressed in Escherichia coli. This is the first report on the aet gene. It encodes a polypeptide composed of 616 (ATCC14234) and 619 (AJ2458) amino acids residues. The Vmax values of these recombinant enzymes during the catalysis of L-alanyl-L-glutamine formation from L-alanine methylester and L-glutamine were 1,010 U/mg (ATCC14234) and 1,154 U/mg (AJ2458). An amino acid sequence similarity search revealed 35% (ATCC14234) and 36% (AJ2458) identity with an α-amino acid ester hydrolase from Acetobacter pasteurianus, which contains an active-site serine in the consensus serine enzyme motif, GxSYxG. In the deduced amino acid sequences of AET from both bacteria, the GxSYxG motif was conserved, suggesting that AET is a serine enzyme.
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  • Noriyuki ITO, Shigeru KAWANO, Junzo HASEGAWA, Yoshihiko YASOHARA
    2011 Volume 75 Issue 11 Pages 2093-2098
    Published: November 23, 2011
    Released: November 23, 2011
    [Advance publication] Released: November 07, 2011
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    Pseudomonas fluorescens KNK08-18, showing (S)-selective transaminase activity, was isolated from soil by an enrichment culture method using (S)-7-methoxy-2-aminotetraline as the main nitrogen source. A transaminase was purified from the strain to homogeneity in seven steps. The relative mass of the enzyme was estimated to be 53 kDa on SDS-polyacrylamide gel electrophoresis and 120 kDa by gel filtration, suggesting a homodimeric structure. The optimal pH and temperature for enzyme activity were about 8.0–8.5 and 40 °C.
    The purified enzyme produced (S)-7-methoxy-2-aminotetraline, (S)-SMA, from 7-methoxy-2-tetralone (SMT) with high enantioselectivity. Although (S)-1-phenylethylamine was the best amino donor, β-alanine and 4-aminobutyric acid, which are good substrates for typical ω-amino acid transaminase (EC 2.6.1.18) and GABA transaminase (2.6.1.19), were not reacted. It aminated a broad range of carbonyl compounds containing aromatic, non-aromatic, and acidic and non-acidic substrates.
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Microbiology & Fermentation Technology Notes
Microbiology & Fermentation Technology Communication
Environmental Science Regular Paper
  • Nozomi TAJIMA, Atsushi KOUZUMA, Kazuhito HASHIMOTO, Kazuya WATANABE
    2011 Volume 75 Issue 11 Pages 2229-2233
    Published: November 23, 2011
    Released: November 23, 2011
    [Advance publication] Released: November 07, 2011
    JOURNALS FREE ACCESS
    Supplementary material
    Mutants of Shewanella oneidensis MR-1 that adapted to an electrode-respiring condition were selected from a random transposon-insertion mutant library to obtain active current-generating mutants and identify relevant cellular components. The mutants were selected in the presence of an electrode (poised at +0.2 V vs. an Ag/AgCl reference electrode) as the sole electron acceptor, and they were isolated on agar plates. Transposon-insertion sites in the isolated mutants were identified by inverse PCR coupled to sequence analyses. Southern blotting using a transposon probe was also performed to detect mutants that grew abundantly on the electrode. These analyses revealed that in many isolated mutants transposons were inserted in genes relevant to the synthesis of cell-surface structures, including SO_3350 (pilus synthesis), SO_3171 (polysaccharide synthesis), SO_3174 (polysaccharide synthesis), and SO_0165 (general secretion pathway). In microbial fuel cells, some of these (the SO_3350 and SO_4704 mutants) generated higher electrical outputs than wild-type MR-1, while the others generated lower outputs. The results suggest that cell-surface structures have a large influence on microbial current generation.
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Environmental Science Communication
  • Min Keun KIM, Shah Md. Asraful ISLAM, Myoung Geun YUN, Jong Min KIM, J ...
    2011 Volume 75 Issue 11 Pages 2264-2268
    Published: November 23, 2011
    Released: November 23, 2011
    [Advance publication] Released: November 07, 2011
    JOURNALS FREE ACCESS
    An experiment was done to determine the efficacy of waste bottom ash as an effective microbial carrier. Bottom ash found to be a suitable microbial carrier. The average of viable cells of Paenibacillus polymyxa GS01 (as a test biocontrol agent) in bottom ash samples was about 108 cfu/10±2 mg. The surface of bottom ash coated with 5% PVA w/v was most effective for improvement of cell viability. TSB medium containing 50 mg/L of MnSO4·H2O was the best for spore production of P. polymyxa GS01. Thus waste bottom ash coating with 5% PVA is likely to be suitable for use as a microbial carrier.
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