Bioscience, Biotechnology, and Biochemistry
Online ISSN : 1347-6947
Print ISSN : 0916-8451
Volume 66 , Issue 8
Showing 1-30 articles out of 30 articles from the selected issue
Review
  • Tomohisa KUZUYAMA
    2002 Volume 66 Issue 8 Pages 1619-1627
    Published: 2002
    Released: June 11, 2003
    JOURNALS FREE ACCESS
      Isoprenoids are synthesized by consecutive condensations of their five-carbon precursor, isopentenyl diphosphate, to its isomer, dimethylallyl diphosphate. Two pathways for these precursors are known. One is the mevalonate pathway, which operates in eucaryotes, archaebacteria, and cytosols of higher plants. The other is a recently discovered pathway, the nonmevalonate pathway, which is used by many eubacteria, green algae, and chloroplasts of higher plants. To date, five reaction steps in this new pathway and their corresponding enzymes have been identified. EC numbers of these enzymes have been assigned by the Nomenclature Committee of the International Union of Biochemistry and Molecular Biology (NC-IUBMB) and are available at http://www.chem.qmw.ac.uk/iubmb/enzyme/reaction/terp/nonMVA.html.
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Analytical Chemistry Regular Paper
Organic Chemistry Regular Papers
  • Fumio HASHIMOTO, Mika TANAKA, Hiroko MAEDA, Shoko FUKUDA, Keiichi SHIM ...
    2002 Volume 66 Issue 8 Pages 1652-1659
    Published: 2002
    Released: June 11, 2003
    JOURNALS FREE ACCESS
      The changes in flower color related to sepal pigmentation of cyanic Delphinium cultivars were investigated during anthesis. The sepal hues of the purple and blue flowered varieties observed on the initial day of unfurling had changed with a decrease in hue angle three days after anthesis. In both the purple and blue cultivars, violdelphin (3) was the major component on day one of anthesis, and the chromaticity improved with increasing sepal concentrations of violdelphin (3) and cyanodelphin (4) after three days of unfurling. The flower hue was dominated by the constitution of acylated anthocyanins, and the chromaticity was ordered by the sepal concentration. The biosynthesis of cyanodelphin (4) from violdelphin (3) was postulated since an increase in the sepal concentration of cyanodelphin (4) was accompanied by a decrease in violdelphin (3). Acylation of the anthocyanins was initiated by an increase in the respective possible precursors, tulipanin (2) and violdelphin (3), to subsequently synthesize violdelphin (3) and cyanodelphin (4) during flowering.
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  • Tsutomu SATO, Shigehiro SASAHARA, Toshiyuki YAMAKAMI, Tsutomu HOSHINO
    2002 Volume 66 Issue 8 Pages 1660-1670
    Published: 2002
    Released: June 11, 2003
    JOURNALS FREE ACCESS
      The functions of Tyr420 and Leu607 were analyzed by constructing various site-directed mutants. The mutation at position 420 into Ala and Gly gave bicyclic α- and γ-polypodatetraene in significant amounts, but with a trace amount of tricyclic malabaricatriene. The kinetic data for and the product distribution of the Y420F mutant indicate that the major function of Tyr420 is to stabilize the 6/6-fused bicyclic cation. Mutation experiments on Leu607 demonstrate that the appropriate steric bulk size at position 607 is required to strongly bind with the product-like conformation formed during the polycyclization process. Introduction of the bulkiest Trp residue into 420 or 607 led to the production of a novel monocyclic triterpene having the (5R,6R)-1,5,6-trimethylcyclohexene ring, named neoachillapentaene, indicating that the enzymatic cyclization proceeded via a constrained boat structure. Folding of the squalene molecule into a boat conformation by squalene cyclase has not been reported before.
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  • Naotaka YAMADA, Daisuke KUSANO, Eiich KUWANO
    2002 Volume 66 Issue 8 Pages 1671-1676
    Published: 2002
    Released: June 11, 2003
    JOURNALS FREE ACCESS
      A variety of 4-aryl- and 4-alkyl-3-(substituted benzylthio)-4H-1,2,4-triazoles were prepared and evaluated for their bleaching activity by the lettuce seedling test. Among the series of tested compounds, 4-(3-fluorophenyl)-3-(4-trifluoromethylbenzylthio)-4H-1,2,4-triazole (39) exhibited the highest bleaching activity, causing complete bleaching symptoms at 10 μM. In the dark condition, compound 39 inhibited the formation of such carotenoids as β-carotene, violaxanthin, neoxanthin and lutein, resulting in the formation of ζ-carotene, phytoene, phytofluene and β-zeacarotene, which were not detected in the untreated control. Treatment by compound 39 at 50 μM resulted in the amount of accumulated ζ-carotene being seven-fold higher than that of phytoene, phytofluene and β-zeacarotene. These results suggest that compound 39 might have interfered with desaturation, especially ζ-carotene desaturation, during carotenoid biosynthesis.
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  • Tomoyuki FUJITA, Daisuke MAKISHIMA, Kohki AKIYAMA, Hideo HAYASHI
    2002 Volume 66 Issue 8 Pages 1697-1705
    Published: 2002
    Released: June 11, 2003
    JOURNALS FREE ACCESS
      New convulsive compounds, brasiliamides A (1) and B (2), were isolated by activity-guided fractionation from okara fermented with a soil isolate of Penicillium brasilianum Batista JV-379. Their structures were elucidated on the basis of spectral and chemical evidence and by X-ray crystallography of the hydrogenated product of 2. In the 1H- and 13C-NMR spectra of 2, the signals were complicated, all being doubled or broadened in several deuterated solvents at room temperature. The conformational change of 2 was clarified as the rotational isomerization of amide bonds in solution by NMR measurements at various temperatures. Four rotamers of 2 at two amide bonds were presented at −60°C in CDCl3, whereas only two isomers were apparent at room temperature, owing to rapid rotation of one of the amide bonds. Brasiliamides A and B respectively showed convulsive activity against silkworms with ED50 values of 300 and 50 μg/g of diet.
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Organic Chemistry Notes
Biochemistry & Molecular Biology Regular Papers
  • Tsuyoshi SAKAI, Takahiro DAIKAI, Hideo MONMA, Hidekatsu MAEDA
    2002 Volume 66 Issue 8 Pages 1646-1651
    Published: 2002
    Released: June 11, 2003
    JOURNALS FREE ACCESS
      A deoxycytidine deaminase that was extremely thermostable in the presence of dithiothreitol was found in a mesophilic bacterium isolated from soil. The bacterium was classified as a Nocardioides sp. The enzyme was purified to a homogeneous protein by treatment at 100°C, ammonium sulfate precipitation, and chromatography on DEAE-Toyopearl, hydroxyapatite, and then Sephacryl S-100. Twenty micrograms of the pure enzyme was obtained from 811 mg of the starting crude protein. After treatment at 50°C for 15 min in the absence of dithiothreitol, enzyme activity was 44% of the starting activity; after treatment at 100°C for 2 h in the presence of 50 mM dithiothreitol, activity was 56% of the starting activity. Dithiothreitol greatly stabilized the enzyme. Activity was maximum at 99°C. The Km values for deoxycytidine, cytidine, and methyl-deoxycytidine were 55.2 , 140, and 130 μM, respectively. The molecular mass was estimated to be 52 kDa by gel permeation chromatography. The enzyme molecule was dissociated into two subunits each of 18 kDa subunit when reduced with mercaptoethanol.
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  • Takeshi SUZUKI, Toru NAKAYAMA, Tatsuo KURIHARA, Tokuzo NISHINO, Nobuyo ...
    2002 Volume 66 Issue 8 Pages 1682-1690
    Published: 2002
    Released: June 11, 2003
    JOURNALS FREE ACCESS
      We cloned a gene coding for a cold-active esterase from a genomic library of Acinetobacter sp. strain No. 6, a psychrotroph isolated from Siberian soil. The gene, aest, encoded a protein of 301 amino acid residues, the deduced sequence of which had less than 17% identity to sequences of known esterases and lipases. However, the esterase seemed to belong to the α/β hydrolase superfamily, because it contained a sequence, Gly-Xaa-Ser-Xaa-Gly (with Xaa an arbitrary amino acid residue), found in most serine hydrolases of this superfamily. Sequence comparison earlier suggested a weak phylogenetic relationship of gene product AEST to the EST group of the esterase-lipase family, which has been found only in eukaryotes. The aest gene was expressed in Escherichia coli BL21(DE3) cells under the control of the T7 promoter, and the expression product was purified to homogeneity and characterized. It catalyzed the hydrolysis of esters with short-chain acyl groups and had lower activation energy and lower thermostability than do mesophilic enzymes, as expected from the cold-adapted nature of this enzyme.
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  • Nozomu KOIZUMI, Kentaro TOYOTA, Sakihito KITAJIMA, Yasuyuki YAMADA, Fu ...
    2002 Volume 66 Issue 8 Pages 1691-1696
    Published: 2002
    Released: June 11, 2003
    JOURNALS FREE ACCESS
      Three genes encoding phosphoenolpyruvate carboxylase were isolated from Nicotiana sylvestris and designated Nsppc1-3. Sequencing of nucleotides showed that the coding sequence and deduced amino acid sequences were highly conserved among the genes, but sequences for noncoding regions including introns and 5′-flanking regions were not conserved. Analysis of the transcript level of the genes by a combination of reverse transcriptase-PCR and restriction fragment polymorphism showed mostNsppc1 in the leaves, stems, roots, and cultured cells of N. sylvestris. β-Glucuronidase activity was detected histochemically in mesophyll cells in leaves, lateral buds, and vascular bundles in roots of transgenic tobacco harboring a chimeric construct of the Nsppc1 promoter and the gene for β-glucuronidase. Deletion analysis indicated the presence of a silencer-like element for basal expression in the promoter region of Nsppc1.
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  • Keitarou SUZUKI, Masaru UYEDA
    2002 Volume 66 Issue 8 Pages 1706-1712
    Published: 2002
    Released: June 11, 2003
    JOURNALS FREE ACCESS
      Prostaglandins (PGs) having antitumor activity such as Δ12,14-PGJ2, Δ12-PGJ2, PGA2 and PGA1 strongly inhibited topoisomerase II (topo II) from human placenta, the potential order of inhibitory activity of the PGs resembling that of the antitumor activity. PGs having no antitumor activity did not inhibit topo II. Δ12,14-PGJ2 to be a potent inhibitor showed inhibitions to some extent against topo I from wheat germ, NIH3T3 and calf thymus gland, and showed no inhibition against the enzymes from Vero, A549, HeLa and COLO 201 cells. Δ12,14-PGJ2 differentially inhibited topo I from different sources. Δ12,14-PGJ2 was a topo inhibitor of the cleavable complex-nonforming type without DNA intercalation.
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Biochemistry & Molecular Biology Notes
Food & Nutrition Science Regular Papers
  • Akihiro TAI, Yoshihito FUJINAMI, Kyoko MATSUMOTO, Daisuke KAWASAKI, It ...
    2002 Volume 66 Issue 8 Pages 1628-1634
    Published: 2002
    Released: June 11, 2003
    JOURNALS FREE ACCESS
      The bioavailability of a series of novel acylated ascorbic acid derivatives, 6-O-acyl-2-O-α-D-glucopyranosyl-L-ascorbic acids (6-Acyl-AA-2G), as an ascorbic acid (AA) supplement was investigated in rats and guinea pigs. Oral administration of 6-Acyl-AA-2G to rats resulted in an increase in the plasma AA level. However, the intact form was not detectable in the plasma by high-performance liquid chromatography, indicating its hydrolysis through the process of absorption. After an intravenous injection to rats of 6-Octa-AA-2G as a representative derivative, the intact form rapidly disappeared from the plasma, being followed by a prolonged and marked elevation of the plasma AA level. Various tissue homogenates from guinea pigs were examined for their releasing activity of AA, 2-O-α-D-glucopyranosyl-L-ascorbic acid (AA-2G) and 6-O-acyl-AA from 6-Acyl-AA-2G. High activity was observed in the small intestine. These hydrolytic activities to AA and 6-O-acyl-AA were completely inhibited by castanospermine, an α-glucosidase inhibitor, and AA-2G was observed as the only resulting hydrolysate, suggesting the participation of α-glucosidase and esterase in the in vivo hydrolysis of 6-Acyl-AA-2G. 6-Octa-AA-2G was found to exhibit an obvious therapeutic effect in scorbutic guinea pigs from its repeated oral administration. These results indicate that 6-Acyl-AA-2G is a readily available source of AA activity in vivo, and may be useful as an effective pharmacological agent and as a promising food additive.
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  • Songsin PHOTCHANACHAI, Alka MEHTA, Naofumi KITABATAKE
    2002 Volume 66 Issue 8 Pages 1635-1640
    Published: 2002
    Released: June 11, 2003
    JOURNALS FREE ACCESS
      The thermal denaturation, aggregation, and degradation of hen egg white ovalbumin dissolved in distilled and deionized water (60 mg/ml, pH 7.5) was investigated by differential scanning calorimetry (DSC), polyacrylamide gel electrophoresis (PAGE), and viscosity measurement. Two independent endothermic peaks were observed up to 180°C by the DSC analysis. The first peak appeared at around 80°C, corresponding to the denaturation temperature of ovalbumin. The second peak occurred around 140°C due to the degradation of protein molecules as judged from the analysis by SDS-PAGE. The viscosity of the ovalbumin solution increased dramatically above 88°C and maintained almost the same value up until heating to 140°C. The increase in viscosity after heating to 88°C was due to the denaturation and subsequent aggregation of ovalbumin molecules as observed by SDS-PAGE. The decrease in viscosity of the samples heated above 150°C appears to have been the result of degradation of the ovalbumin molecules.
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  • Tetsuo IIDA, Yumiko YOSHIKI, Shinich SOMEYA, Kazuyoshi OKUBO
    2002 Volume 66 Issue 8 Pages 1641-1645
    Published: 2002
    Released: June 11, 2003
    JOURNALS FREE ACCESS
      The properties of photon emission arising from a browned product were investigated. The photon intensity of the browned product was proportional to the absorbancy at 420 nm, and was influenced by the amino acid structure. The fluorescence spectrum showed similar compounds in the browned product to be related with this photon emission. Superoxide and hydrogen peroxide contributed highly to this photon emission, and several redox compounds enhanced the photon intensity at appropriate concentrations. Our work suggests that the photon intensity was closely related to the reactive oxygen species (ROS) generated from the browned product, and this effect may be utilized to evaluate the function and quality of browned food.
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  • Naohisa NOSAKA, Michio KASAI, Masahiro NAKAMURA, Isamu TAKAHASHI, Megu ...
    2002 Volume 66 Issue 8 Pages 1713-1718
    Published: 2002
    Released: June 11, 2003
    JOURNALS FREE ACCESS
      The objective of this study was to investigate effects of dietary medium-chain triacylglycerols (MCTs) on serum lipid levels, liver function, and hepatic fat accumulations in healthy men. Eleven subjects consumed 2200-2600 kcal daily, of which 70-80 g was fat; the fat included 40 g of MCTs or else 40 g of long-chain triacylglycerols (blended vegetable oil). The diet was followed for 4 weeks in this controlled double-blind study. At the end of the experiment, significant differences were not found in the concentrations of serum total cholesterol, very low density lipoprotein cholesterol, low density lipoprotein cholesterol, and high density lipoprotein cholesterol between the groups. Serum triglycerol levels were not significantly different in the groups. Adverse effects from ingestion of MCTs on liver functions, the liver-to-spleen ratio on computed tomography (an index of fatty liver), or results of blood tests were not seen. The results suggest that the long-term effects of dietary MCTs on serum cholesterol were similar to those of unsaturated fatty acids found abundantly in vegetable oil, and that consumption of MCTs in the amount of 40 g/day for a month does not cause liver fat accumulation or liver dysfunction.
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  • Pramote KHUWIJITJARU, Shuji ADACHI, Ryuichi MATSUNO
    2002 Volume 66 Issue 8 Pages 1723-1726
    Published: 2002
    Released: June 11, 2003
    JOURNALS FREE ACCESS
      The solubility in water of saturated fatty acids with even carbon numbers from 8 to 18 was measured in the temperature range of 60 to 230°C and at a pressure of 5 or 15 MPa. The pressure had no significant effect on the solubility. The solubility of the fatty acids increased with increasing temperature. At temperatures higher than about 160°C, the logarithm of the solubility in mole fraction was linearly related to the reciprocal of the absolute temperature for each fatty acid, indicating that the water containing solubilized fatty acid molecules formed a regular solution at the higher temperatures. The enthalpy of a solution of the fatty acids in water, which was evaluated from the linear relationship at the given temperatures, increased linearly with the carbon number of the fatty acid.
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Food & Nutrition Science Notes
  • Hiroshi MATSUZAKI, Shin-ichi KATSUMATA, Ritsuko MASUYAMA, Mariko UEHAR ...
    2002 Volume 66 Issue 8 Pages 1737-1739
    Published: 2002
    Released: June 11, 2003
    JOURNALS FREE ACCESS
      We examined sex differences in kidney mineral concentrations and urinary albumin excretion in rats given feed containing various phosphorus (P) levels. With feed that was 0.6%, 0.9%, 1.2%, and 1.5%P, kidney calcium and P concentrations were higher in female rats than in male rats. With 1.2% or 1.5%P, urinary albumin excretion was higher in the female rats. The sex of the animal affected the kidney mineral concentrations and urinary albumin excretion in rats with a high P intake.
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  • Ta Thi Tuyet MAI, Kaori IGARASHI, Rieko HIRUNUMA, Satoko TAKASAKI, Mas ...
    2002 Volume 66 Issue 8 Pages 1744-1747
    Published: 2002
    Released: June 11, 2003
    JOURNALS FREE ACCESS
      The effects of brewer's yeast cell walls and two of its components, glucan and mannan, on the absorption of 59Fe by anemic rats were investigated. After administration of the label, the percentage of 59Fe taken up into the blood of group given glucan was generally similar to that of a group given yeast cell walls, both values were higher than in controls. The incorporation of 59Fe into the small intestines was higher in the group given glucan than in the controls or a group given a glucan—mannan mixture. Glucan is the main substance in yeast cell walls that increases iron absorption.
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  • Jale BALKAN, Öznur KANBAGLI, Aydan HATIPOGLU, Mutlu KÜ&Ccedi ...
    2002 Volume 66 Issue 8 Pages 1755-1758
    Published: 2002
    Released: June 11, 2003
    JOURNALS FREE ACCESS
      The effect of a high-cholesterol diet with or without taurine on lipids and oxidative stress in the plasma, liver and aorta of rabbits was investigated. The animals were maintained on a basal diet (control), a high-cholesterol diet (HC, 1% w/w), or a high- cholesterol diet supplemented with taurine (HCHT, 2.5% w/w) for two months. Taurine has an ameliorating effect on atherosclerosis together with a decreasing effect on the cholesterol and triglyceride levels in rabbits fed on an HC diet. The HCHT diet caused a significant decrease in the malondialdehyde (MDA) and diene conjugate (DC) levels in the plasma, liver and aorta of rabbits as compared to the HC group. This treatment did not alter the antioxidant system in the liver of rabbits in the HC group. Our findings indicate that taurine ameliorated oxidative stress and cholesterol accumulation in the aorta of rabbits fed on the HC diet and that this effect may be related to its antioxidative potential as well as its reducing effect on serum lipids.
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  • Yasuhiko SHIMADA, Tatsuya MORITA, Kimio SUGIYAMA
    2002 Volume 66 Issue 8 Pages 1759-1763
    Published: 2002
    Released: June 11, 2003
    JOURNALS FREE ACCESS
      Shiitake mushrooms (Lentinus edodes) are a hypocholesterolemic and affect phospholipid and fatty acid metabolism in rats. In this study, the effects of 2% shiitake in the diet on fatty acid and molecular species profiles of liver microsomal and plasma phosphatidylcholine (PC) were investigated in rats fed diets containing different levels (1-20%) of corn oil, a linoleic-acid-rich fat. The proportion of 18:2n-6 in PC increased depending on the parcent corn oil, and L. edodes further increased the proportion at all corn oil levels. The proportion of 20:4n-6 was lower in rats fed L. edodes than in rats fed control diets irrespective of the parcent corn oil. L. edodes selectively increased the proportion of 16:0-18:2 molecular species and decreased the proportion of 18:0-20:4 molecular species in PC. These results indicate that the effects of L. edodes on fatty acid and molecular species profiles of PC are stronger than that of the dietary corn oil level.
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  • Masaaki OKABE, Mariko OJI, Ikuo IKEDA, Hirofumi TACHIBANA, Koji YAMADA
    2002 Volume 66 Issue 8 Pages 1768-1771
    Published: 2002
    Released: June 11, 2003
    JOURNALS FREE ACCESS
      A tocotrienol (T3) mixture was intragastricaly administered to Sprague-Dawley rats, and the T3 levels in various tissues were measured 0, 4, 8 and 24 hr after the administration. In blood clots, brain, thymus, testes, vice-testes and muscles, T3 homologues were not detected at all. In epididymal adipose, renal adipose, subcutaneous adipose and brown adipose tissues and in the heart, the T3 levels were maintained or increased for 24 hr after the administration. In the serum, liver, mesenteric lymph node, spleen and lungs, the T3 levels were highest 8 hr after the T3 administration. These results suggest that the distribution and metabolism of T3 in the rat vary considerably among different tissues.
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Microbiology & Fermentation Technology Regular Paper
  • Takehiko ISHIDA, Yasushi SUGANO, Tomonori NAKAI, Makoto SHODA
    2002 Volume 66 Issue 8 Pages 1677-1681
    Published: 2002
    Released: June 11, 2003
    JOURNALS FREE ACCESS
      Acetan is a water-soluble polysaccharide produced by a bacterial cellulose (BC) producer, Acetobacter xylinum. An acetan-nonproducing mutant, EP1, was generated from wild-type A. xylinum BPR2001 by the disruption of aceA, which may act to catalyze the first step of the acetan biosynthetic pathway in this bacterium. EP1 produced less BC than the wild-type strain. However, when EP1 was cultured in a medium containing acetan, BC production was stimulated and the final yield of BC was equivalent to that of BPR2001. The culture broth containing acetan was more viscous and the free cell number was higher than that of the broth without the polysaccharide, so acetan may hinder the coagulation of BC in the broth. The addition of 1.5 g/l agar also increased BC production; we concluded that acetan and BC syntheses were not directly related on the genetic level.
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Microbiology & Fermentation Technology Note
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