Bioscience, Biotechnology, and Biochemistry
Online ISSN : 1347-6947
Print ISSN : 0916-8451
Volume 64 , Issue 2
Showing 1-50 articles out of 51 articles from the selected issue
Organic Chemistry Regular Papers
  • Masayasu TANAKA, Takane FUJIMORI, Kensuke NABETA
    2000 Volume 64 Issue 2 Pages 244-247
    Published: 2000
    Released: March 03, 2005
    JOURNALS FREE ACCESS
      Feeding experiments of labeled acetates to Nimbya scirpicola proved the carbon origin of the straight-chain polyketide, depudecin. Differential hydrogen exchange of the 2H label originating from 2H labeled acetate along the polyketide chain occurred. In particular, the deuterium of an epoxide methine at C-3 was lost to a substantial extent in the formation of depudecin.
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  • Naoki ABE, Aya NEMOTO, Yukiko TSUCHIYA, Hiroshi HOJO, Akira HIROTA
    2000 Volume 64 Issue 2 Pages 306-313
    Published: 2000
    Released: March 03, 2005
    JOURNALS FREE ACCESS
      The radical scavenging mechanisms for the 2-pyrone compound, 4-hydroxy-3,6-dimethyl-2H-pyrane-2-one (1), and the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical (4) in several solvent systems were evaluated by the quantitative change in compounds detected at 270 nm and subsequent HPLC analyses. The HPLC profile for each condition suggested that the reaction proceeded by a different mechanism in each solvent system. In organic solvents (CHCl3, iso-propanol, and EtOH), 1- [4-(3,4-dihydro-3,6-dimethyl-2,4-dioxo-2H-pyran-3-yl) phenyl]-1-phenyl-2-picrylhydrazine (2) was produced as an adduct of the DPPH radical and 1. On the other hand, the reaction in a buffer solution (an acetate buffer at pH 5.5) gave several degradation products with 1-[4-(2,3-dihydro-2,5-dimethyl-3-oxo-fur-2-yl) phenyl]-1-phenyl-2-picrylhydrazine (5), this being structurally elucidated by spectroscopic analyses. The decrease of the DPPH radical in each reaction system suggests that compound 1 could scavenge about 1.5-1.8 equivalents of the radical in organic solvents and about 3.5-3.9 in the buffer solution.
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  • Tadashi SHIRAIWA, Kohya TADOKORO, Joji ISHIKAWA, Haruyuki TANAKA, Toor ...
    2000 Volume 64 Issue 2 Pages 341-347
    Published: 2000
    Released: March 03, 2005
    JOURNALS FREE ACCESS
      In order to synthesize four stereoisomers of 1,4-thiazane-3-carboxylic acid 1-oxide (TCA•SO), (S)-1,4-thiazane-3-carboxylic acid [(S)-TCA], which is one of the precursors, was prepared by the asymmetric transformation (combined isomerization-preferential crystallization) of (RS)-TCA. This asymmetric transformation was used (2R, 3R)-tartaric acid [(R)-TA] as a resolving agent and salicylaldehyde as the epimerization catalyst in propanoic acid at 110°C to afford a salt of (S)-TCA with (R)-TA in 100% de with a yield of over 90%. Optically pure (S)-TCA was obtained by treating the salt with triethylamine in methanol in a yield of over 80%, based on (RS)-TCA as the starting material. In addition, asymmetric transformation of (R)-TCA gave (S)-TCA in a yield of 60-70%. (S)-TCA was oxidized by hydrogen peroxide in dilute hydrochloric acid to selectively crystallize (1S, 3S)-TCA•SO. (1R, 3S)-TCA•SO of 70% de from the filtrate was allowed to form a salt with (R)-TA after a treatment with triethylamine to give (1R, 3S)-TCA•SO as a single diastereoisomer. (1R, 3R)- and (1S, 3R)-TCA•SO were also prepared by starting from (R)-TCA that had been synthesized from L-cysteine.
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  • Atsuhito KUBOKI, Takashi ISHIHARA, Eiko KOBAYASHI, Hiromichi OHTA, Tak ...
    2000 Volume 64 Issue 2 Pages 363-368
    Published: 2000
    Released: March 03, 2005
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      N4-Acetylcytidine (77%) and 2′,3′-O,N4-triacetylcytidine (95%) were obtained from the hydrolysis of a common precursor, the peracetylated form of cytidine with Aspergillus niger lipase (Amano A) and Burkholderia cepacia esterase (SC esterase S), respectively, under very mild conditions. The experimental procedure for the conversion of triacetylcytidine to a corresponding phosphoramidite (82%), an intermediate for sugar nucleotide synthesis, is also elaborated.
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Organic Chemistry Notes
  • Suratwadee JIWAJINDA, Vilai SANTISOPASRI, Hajime OHIGASHI
    2000 Volume 64 Issue 2 Pages 420-423
    Published: 2000
    Released: March 03, 2005
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      Chemical investigation of naturally occurring plant growth inhibitors from Rutaceous plants in Thailand led us to identify five 7-methoxycoumarins and one 5,7-dimethoxycoumarin from Murraya paniculata, and six furanocoumarins from Citrus aurantifolia. Of these compounds, murranganon senecioate (1) is a new natural compound found in M. paniculata. Minumicrolin (6) was found to be highly active against the 2nd leaf sheath elongation of rice seedlings.
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  • Francis ADJEI-AFRIYIE, Chul-Sa KIM, Masami TAKEMURA, Masahiro ISHIKAWA ...
    2000 Volume 64 Issue 2 Pages 443-446
    Published: 2000
    Released: March 03, 2005
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      Adult females of the white-back planthopper, Sogatella furcifera, showed characteristic behavior of stylet sheath deposit on a parafilm membrane when fed on a 2% aqueous crude rice leaf and stem extract containing 15% sucrose. Subsequent bioassays revealed that the butanol-soluble fraction of the extract was highly active against the insects. When the butanol fraction was chromatographed on an ODS open column and eluted in sequence with a mixture of an increasing concentration of methanol in water, the 40% methanol fraction was separated as the most active. A further bioassay of the HPLC components in the active fraction revealed that two major components (1 and 3) stimulated the high probing activity of the white-back planthopper only when they were combined. Of the active components, one component (3) was identified to be tricin 5-O-glucoside by spectroscopic analyses.
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Biochemistry & Molecular Biology Regular Papers
  • Henri CHAHINIAN, Guillaume VANOT, Aida IBRIK, Nathalie RUGANI, Louis S ...
    2000 Volume 64 Issue 2 Pages 215-222
    Published: 2000
    Released: March 03, 2005
    JOURNALS FREE ACCESS
      Penicillium cyclopium, grown in stationary culture, produces a type I lipase specific for triacylglycerols while, in shaken culture, it produces a type II lipase only active on partial acylglycerols. Lipase II has been purified by ammonium sulfate precipitation and chromatographies on Sephadex G-75 and DEAE-Sephadex. The enzyme exists in several glycosylated forms of 40-43 kDa, which can be converted to a single protein of 37 kDa by enzymatic deglycosylation. Activity of lipase II is maximal at pH 7.0 and 40°C. The enzyme is stable from pH 4.5 to 7.0. Activity is rapidly lost at temperatures above 50°C. The enzyme specifically hydrolyzes monoacylglycerols and diacylglycerols, especially of medium chain fatty acids. The sequence of the 20 first amino acid residues is similar to the N-terminal region of P. camembertii lipase and partially similar to lipases from Humicola lanuginosa and Aspergillus oryzae, but is different from Penicillium cyclopium lipase I. However, it can be observed that residues of valine and serine at positions 2 and 5 in Penicillium cyclopium lipase II are conserved in Penicillium expansum lipase, of which 16 out of the 20 first amino acid residues are similar to Penicillium cyclopium lipase I.
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  • RYU Su-Jin, Doman KIM, Hwa-Ja RYU, Seiya CHIBA, Atsuo KIMURA, Donal F. ...
    2000 Volume 64 Issue 2 Pages 223-228
    Published: 2000
    Released: March 03, 2005
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      A novel glucanhydrolase from a mutant of Lipomyces starkeyi ATCC 74054 was purified. The single protein (100 kDa) showed either dextranolytic or amylolytic activity. We referred to the glucanhydrolase as a DXAMase. The DXAMase was produced in a starch medium and it was 3.75-fold more active for hydrolysis of the purified insoluble-glucan of Streptococcus mutans than Penicillium funiculosum dextranase. Aggregation of S. mutans cells with dextran and adherence to glass were eliminated by incubating with the DXAMase. The addition of DXAMase (0.1 IU/ml) to the mutansucrase reaction digest with sucrose reduced the formation of insoluble-glucan about 80%. Also the DXAMase (0.5 IU/ml) removed 80% of the pre-formed sucrose-dependent adherent film. These in vitro properties of L. starkeyi KSM 22 DXAMase are desirable for its application as a dental plaque control agent.
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  • Toyohisa INOUE, Haruyuki IEFUJI, Tsutomu FUJII, Hiroshi SOGA, Kaname S ...
    2000 Volume 64 Issue 2 Pages 229-236
    Published: 2000
    Released: March 03, 2005
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      Ethanol-sensitive mutants (es1 to es10) were isolated from sake yeast, Saccharomyces cerevisiae SY-32. These mutants were unable to grow at 7% ethanol at which the wild type strain SY-32 does grow. The mutants had a variety of fermentation rates and viabilities in the presence of ethanol. The gene ERG6, com- plementing the ethanol-sensitive mutation of es5, was cloned from an SY-32 gene library. ERG6 encodes S-adenosylmethionine: delta 24-sterol-C-methyltransferase (EC 2.1.1.41) in the ergosterol synthetic pathway. Mutant es5 had a reduced ability to synthesize ergosterol. An erg6 disruptant was also ethanol-sensitive. These results suggested that ERG6 plays an important role in the ethanol tolerance of S. cerevisiae.
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  • Masaaki ITO, Kohei ODA
    2000 Volume 64 Issue 2 Pages 261-267
    Published: 2000
    Released: March 03, 2005
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      We found a tyrosinase, which has high activity in the presence of organic solvents, in the culture filtrate of Streptomyces sp. REN-21. The organic solvent resistant tyrosinase (OSRT) was purified from the culture filtrate by three column chromatographies. About 1.2 mg of purified OSRT was obtained from 5.6 liters of the culture filtrate with a yield of 26.0%. The purified enzyme had a single polypeptide chain with a molecular mass of about 32,000 Da. The optimum pH and temperature of OSRT were pH 7.0 and 35°C using L-β-(3,4-dihydroxyphenyl)alanine (L-DOPA) as substrate. OSRT showed stereospecificity toward L-, DL-, and D-enantiomers of DOPA or tyrosine. OSRT had 44% of the activity of the control even in the presence of 50% ethanol, while a mushroom tyrosinase showed only 6% activity under the same conditions. Moreover, OSRT retained its original activity even after 20 h of incubation at 30°C in the presence of 30% ethanol.
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  • Chikako MORINAGA, Kazuo IZUMI, Hitoshi SAWADA, Michiko TAKAGI SAWADA
    2000 Volume 64 Issue 2 Pages 268-274
    Published: 2000
    Released: March 03, 2005
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      In the oocyte maturation process of the starfish Asterina pectinifera, the extent of inhibition of germinal vesicle breakdown (GVBD) by the proteasome inhibitor MG115 (benzyloxycarbonyl-leucyl-leucyl-norvalinal), as well as the timing of activation of pre-MPF (inactive maturation promoting factor) and 26S proteasome assembly, were found to be dependent on the concentration of the maturation-inducing hormone 1-methyladenine (1-MeAde). Activation of pre-MPF was accelerated by increasing the concentration of 1-MeAde, while there was little effect on the time required for GVBD. Assembly of the 26S proteasome was also accelerated by increasing the concentration of 1-MeAde. These results indicate that a higher concentration of 1-MeAde triggers acceleration of the assembly and increase in the activity of the 26S proteasome, which results in activation of pre-MPF, although there is little effect on the timing of GVBD. It was also clarified that the timing of GVBD is controlled by a rate-liming step after MPF-activation.
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  • Takashi AKAMATSU, Hisataka TAGUCHI
    2000 Volume 64 Issue 2 Pages 275-279
    Published: 2000
    Released: March 03, 2005
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      Competent cells of Bacillus subtilis were transformed with chromosomal DNA in lysates of protoplasts of B. subtilis or B. amyloliquefaciens. The interspecific transformation frequency of B. subtilis by cysA in a conserved region was 3.1×104 transformants per μg DNA, 60 times higher than that for conventional transformation using purified DNA. Increased interspecific transformation frequencies of B. subtilis were also observed for arg-1, lys-1, leuB, aroG, thr-5, hisH, or metC markers outside the conserved region (3.1×10~5.2×102 transformants per μg DNA). An in- terspecific cotransformation ratio (33-50%) as high as an intraspecific one (46%) using purified DNA was also detected between cysA and rpsL markers, which are separated by 16 kb on the B. subtilis chromosome. Interspecific double transformation of the cysA-arg-1 or cysA-metC marker was observed, which have not been detected for conventional transformation. The involvement of mutS in the interspecific transformation was not significant.
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  • Yan-Jun JIA, Hiroyuki ITO, Hirokazu MATSUI, Mamoru HONMA
    2000 Volume 64 Issue 2 Pages 299-305
    Published: 2000
    Released: March 03, 2005
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      We have already described how 1-aminocyclopropane-1-carboxylic acid (ACC), which is a precursor of the plant hormone ethylene, is synthesized in Penicillium citrinum through the same reaction by the catalysis of ACC synthase [EC 4.4.1.14] as in higher plants. In addition, ACC deaminase [EC 4.1.99.4], which degrades ACC to 2-oxobutyrate and ammonia, was also purified from this strain. To study control of induction of ACC deaminase in this organism, we have isolated and analyzed the cDNA of P. citrinum ACC deaminase and studied the expression of ACC deaminase mRNA in P. citrinum cells. By the analysis of peptides from the digests of the purified and modified ACC deaminase with lysylendopeptidase, 70% of its amino acid sequences were obtained. These amino acid sequences were used to identify a cDNA, consisting of 1,233 bp with an open reading frame of 1,080 bp encoding ACC deaminase with 360 amino acids. The deduced amino acids from the cDNA are identical by 52% and 45% to those of enzymes of Pseudomonas sp. ACP and Hansenula saturnus. Through Northern blot analysis, we found that the mRNA of ACC deaminase was expressed in P. citrinum cells grown in a medium containing 0.05% L-methionine. These findings suggest that ACC synthesized by ACC synthase and accumulated in P. citrinum intracellular spaces can induce the ACC deaminase that degrades the ACC.
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  • Yoshihiro KAWASAKI, Kaoru SATO, Hiroshi SHINMOTO, Shun’ichi DOSA ...
    2000 Volume 64 Issue 2 Pages 314-318
    Published: 2000
    Released: March 03, 2005
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      We have previously demonstrated that lactoferrin was incorporated into B lymphocytes and that a trypsin treatment for a short period reduced the number of lactoferrin molecules incorporated into B lymphocytes. An N-terminal sequence analysis revealed that the mild trypsin treatment had cleaved the three N-terminal amino acids, Gly1-Arg2-Arg3. Chemical conjugation of lost sequence analogue Gly-Arg-Arg-Gly with the mildly digested lactoferrin recovered the interaction with B lymphocytes, while conjugation of acetyl-Arg-Arg-Gly, a deamino analogue of Gly-Arg-Arg-Gly, did not recover the interaction. This shows that the N-terminal basic region containing N-terminal Gly played an important role in the interaction with B lymphocytes. Acylation of the amino groups of lactoferrin also significantly reduced the interaction with B lymphocytes, and an O-methylisourea treatment of the amino groups, which preserved the positive charge, hardly affected the interaction. These results suggest that both the N-terminal basic region and the basic characteristics of the whole molecule contributed to its interaction with B lymphocytes.
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  • Masaru KATO, Kyoko TAKEHARA, Masako KETTOKU, Kazuo KOBAYASHI, Toshiyuk ...
    2000 Volume 64 Issue 2 Pages 319-326
    Published: 2000
    Released: March 03, 2005
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      A glycosyltrehalose-producing enzyme from Sulfolobus solfataricus KM1 catalyzes a conversion of maltooligosaccharides to glycosyltrehaloses and also hydrolyzes maltooligosaccharides to liberate glucose, as a side reaction. From the sum of the conversion and hydrolysis reaction rates, the rate parameters involved in the “splitting” of the α-1,4 glucosidic linkage were calculated. From the data obtained, the subsite structure for maltooligosaccharides was identified. From the analysis of the hydrolysate of maltotriose in [18O] labeled H2O, the hypothesis of the C1-O bond splitting and the formation of a glycosyl (maltosyl)-enzyme intermediate was strongly supported. From the analysis of the reaction product in the presence of [3H] labeled glucose, the occurrence of intermolecular transglycosylation was confirmed. These data strongly support the suggestion that the catalytic mechanism of this enzyme is a transglycosylation.
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  • Shin OGATA, Masayo TAKEUCHI, Hiroaki FUJITA, Katsumi SHIBATA, Katsuzum ...
    2000 Volume 64 Issue 2 Pages 327-332
    Published: 2000
    Released: March 03, 2005
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      In our previous paper, we have reported that niacin-related compounds, particularly picolinic acid, dipicolinic acid, and isonicotinamide, induced apoptosis in HL-60 cells but that niacin did not. Moreover, picolinamide, N1-methylnicotinamide, 6-aminonicotinamide, quinolinic acid, and cinchomeronic acid also had the function of DNA fragmentation in HL-60 cells analyzed by flow cytometry, the ratio of DNA fragmentation finally being about 40% after treatment with these compounds at 10 mM for 24 h. In this study, we found that these compounds also induced apoptosis in HL-60 cells. The wide-spectrum caspase inhibitors prevented DNA fragmentation induced by these compounds. Interestingly, 6-aminonicotinamide induced apoptosis at a comparatively low concentration, while picolinic acid, dipicolinic acid, and isonicotinamide did not at 1 mM. Our results suggest that both NAD metabolism and NAD biosynthesis may be related to the process of apoptosis induced by niacin-related compounds.
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  • Katsuyuki OKAMOTO, Hirofumi NAKANO, Tsunneya YATAKE, Taro KISO, Sumio ...
    2000 Volume 64 Issue 2 Pages 333-340
    Published: 2000
    Released: March 03, 2005
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      Flavobacterium johnsonae was isolated as a microorganism that produced a β-glucosidase with hydrolytic activity of β-glucosyl ester linkages in steviol glycosides. The enzyme was purified to homogeneity from a cell-free extract by streptomycin treatment, ammonium sulfate fractionation, and column chromatographies on S-Sepharose and phenyl-Toyopearl. The molecular mass of the purified enzyme was about 72 kDa by SDS-PAGE. An isoelectric point of pI 8.8 was estimated by isoelectric focusing. The enzyme was most active at pH 7.0, and was stable between pH 3.0 and 9.0. The optimum temperature was 45°C, and the enzyme was stable below 35°C. The enzyme hydrolyzed glucosyl ester linkages at site 19 of rebaudioside A, stevioside, and rubusoside, although it could not degrad β-glucosidic linkages at site 13 of rebaudioside B or steviol bioside. The enzyme acted on aryl β-glucosides such as p-nitrophenyl β-glucoside, phenyl β-glucoside, and salicin, and glucobioses such as sophorose and laminaribiose. The enzyme activity on Rub was inactivated completely by Hg2+, and reduced by Fe3+, Cu2+, p-chloromercuric benzoate, and phenylmethylsulfonyl fluoride (residual activity; 67.9-84.8%). The pNPG hydrolysis was also inactivated to almost the same degrees. Kinetic behaviors in the mixed substrate reactions of rebaudioside A and steviol monoside, and of steviol monoglucosyl ester and phenyl β-glucoside suggested the glucosidic and glucosyl ester linkages were hydrolyzed at a single active site of the enzyme.
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  • Yoshihiro KAWASAKI, Seiki TAZUME, Keiko SHIMIZU, Hideyuki MATSUZAWA, S ...
    2000 Volume 64 Issue 2 Pages 348-354
    Published: 2000
    Released: March 03, 2005
    JOURNALS FREE ACCESS
      Adherence is an essential and prerequisite step for the colonization of mucosal surfaces by enterotoxigenic Escherichia coli (ETEC). We studied the effect of bovine lactoferrin (BLF) on the adherence of ETEC to human epithelial cells in vitro, and to intestinal mucosa of ICR germfree mice in vivo. In the in vitro study, BLF was found to inhibit the adherence of ETEC. This adhesion-inhibiting activity of BLF was found to lessen with decreasing BLF concentration, but the data obtained suggest a positive inhibitory effect of BLF against the adhesion of ETEC cells. In the in vivo study, the counts of adherent bacteria in various sections of the intestinal tract (duodenum, jejunoileum, and large intestine) were lower in the BLF group than in the control group, suggesting the possible action of BLF as an intestinal tract adherence-blocking agent with regards to ETEC.
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  • Dong Ha OH, Kwan Jeong SONG, Yong Uk SHIN, Won-Il CHUNG
    2000 Volume 64 Issue 2 Pages 355-362
    Published: 2000
    Released: March 03, 2005
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      A fruit-specific and pathogenesis-related 5/thaumatin-like (PR5/TL), 31-kDa protein was isolated by 2D-PAGE from fully-grown apples (Malus domestica cv. Fuji) and named Mdtl1 (Malus domestica thaumatin-like protein 1). Using the N-terminal sequence of the protein, the full-length cDNA encoding Mdtl1 was isolated. The cDNA clone (Mdtl1) consists of 944 bp with an open reading frame (ORF) of 744 bp encoding a protein of 247 amino acids. The deduced amino acid sequence of Mdtl1 shows high similarity to the sequences of PR5/TL proteins. Mdtl1 is a slightly acidic protein with a putative signal peptide and a putative N-glycosylation site, and lacks a C-terminal extension. This suggests that Mdtl1 is an apoplastic glycoprotein. Results of northern blotting indicated that expressions of Mdtl1 are developmentally regulated. Southern blot analysis showed that Mdtl1 may be present as a single copy, and there exist other genes closely related to Mdtl1 in the apple genome.
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  • Shin-ichi SATO, Kaeko KAMEI, Mai TANIGUCHI, Hideki SATO, Ryo TAKANO, H ...
    2000 Volume 64 Issue 2 Pages 393-398
    Published: 2000
    Released: March 03, 2005
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      MCTI-II (Momordica charantia trypsin inhibitor II) isolated from bitter gourd (Momordica charantia LINN.) seeds is one of the serine protease inhibitors of the squash family. We cloned cDNA that encodes MCTI-II and constructed an expression system for MCTI-II by using a baculovirus vector. The recombinant baculovirus was inoculated to early fifth-instar larvae of the silkworm (strain: Shunrei×Shougetsu). Four days after infection, the hemolymph of silkworm larvae was collected and the recombinant protein was purified. Two kinds of expressed MCTI-II protein were obtained. An amino acid sequence analysis of the two proteins indicates that both were similar to the authentic inhibitor, except for the addition of a tripeptide derived from the vector at the N-terminus. One of the two inhibitors (MCTI-II A) resulted in a single PTH-amino acid in each Edman degradation cycle, while the other (MCTI-II B) resulted in two PTH-amino acids, suggesting the occurrence of cleavage of the reactive site. The inhibitory activities of MCTI-II expressed toward trypsin are examined in terms of the Ki value, these being 6.4×10-10 M for MCTI-II A and 5.2×10-10 M for MCTI-II B.
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Biochemistry & Molecular Biology Notes
Food & Nutrition Science Regular Papers
  • Yasunori FUKUMORI, Norio MAEDA, Hiroyuki TAKEDA, Shuichi ONODERA, Nori ...
    2000 Volume 64 Issue 2 Pages 237-243
    Published: 2000
    Released: March 03, 2005
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      Blood glucose and insulin responses and gastric emptying were examined in rats intubated with sucrose or soluble starch that contained adenosine, inosine and cytosine.
      The increase in serum glucose and insulin levels in the rats following loading with sucrose (2.5 g/kg of body weight) or soluble starch (1.875 g/kg of body weight) was significantly reduced by the administration of adenosine, inosine and cytosine (0.0625-0.125 g/kg of body weight).
      The gastric emptying rates were only marginally affected by the nucleoside administration. The activities of sucrase, maltase, isomaltase and glucoamylase in a crude preparation from the small intestinal mucosa of rats were mildly inhibited by the nucleosides.
      The decrease in blood glucose and insulin levels may have been in response to a decrease in glucose absorption caused by the inhibiting effect of the nucleosides on the mucosal enzymes that digest sucrose, maltose, and malto- and isomalto-oligosaccharides.
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  • Takami KAKUDA, Ayumu NOZAWA, Tomonori UNNO, Noritaka OKAMURA, Osamu OK ...
    2000 Volume 64 Issue 2 Pages 287-293
    Published: 2000
    Released: March 03, 2005
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      In this study, the inhibiting action of theanine on the excitation by caffeine at the concentration regularly associated with drinking tea was investigated using electroencephalography (EEG) in rats. First, the stimulatory action by caffeine i.v. administration at a level higher than 5 μmol/kg (0.970 mg/kg) b.w. was shown by means of brain wave analysis, and this level was suggested as the minimum dose of caffeine as a stimulant. Next, the stimulatory effects of caffeine were inhibited by an i.v. administration of theanine at a level higher than 5 μmol/kg (0.781 mg/kg) b.w., and the results suggested that theanine has an antagonistic effect on caffeine’s stimulatory action at an almost equivalent molar concentration. On the other hand, the excitatory effects were shown in the rat i.v. administered 1 and 2 μmol/kg (0.174 and 0.348 mg/kg) b.w. of theanine alone. These results suggested two effects of theanine, depending on its concentration.
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  • Miou TODA, Jun KAWABATA, Takanori KASAI
    2000 Volume 64 Issue 2 Pages 294-298
    Published: 2000
    Released: March 03, 2005
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      The ellagitannins, casuarictin and eugeniin, were isolated as rat intestinal maltase inhibitors from methanol extracts of clove (Syzgium aromaticum). Eugeniin showed inhibitory activity with an IC50 value of 10-3 M. A structure-activity relationship study among the isolates and their related compound, penta-O-galloyl-β-D-glucose, indicates that an increasing number of galloyl units in the molecule might lead to an increase in the inhibitory activity. Eugeniin also inhibited maltase activity toward the human intestinal epithelial cell line, Caco-2.
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  • Fumihito TAKENAKA, Hirofumi UCHIYAMA, Takeshi IMAMURA
    2000 Volume 64 Issue 2 Pages 378-385
    Published: 2000
    Released: March 03, 2005
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      α-D-Glucosylglycerol (GG) was found for the first time in sake (Japanese rice wine) in an amount of about 0.5%. GG was also found in miso and mirin which had been brewed by using koji. GG was hydrolyzed into glucose and glycerol in an equimolar ratio with maltase (EC 3.2.1.20, α-glucosidase from yeast), but not with emulsin (EC 3.2.1.21, β-glucosidase from almond). The retention times and mass spectra of trimethylsilyl derivatives by a GC-MS analysis of GG in sake were comparable to those of various GG samples synthesized by glycol cleavage. It was proven that GG in sake consisted of three components, viz., 2-O-α-D-glucosylglycerol (GG-II), (2R)-1-O-α-D-glucosylglycerol (R-GG-I) and (2S)-1-O-α-D-glucosylglycerol (S-GG-I). The ratio of the three components in GG was 6:66:28 for sake. It is considered that GG was formed by transglucosylation of the glucosyl groups to glycerol by α-glucosidase from koji in the sake mash.
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Food & Nutrition Science Notes
Microbiology & Fermentation Technology Regular Papers
  • Tomohisa KATSUDA, Masayuki AZUMA, Jyoji KATO, Susumu TAKAKUWA, Hiroshi ...
    2000 Volume 64 Issue 2 Pages 248-253
    Published: 2000
    Released: March 03, 2005
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      Ethanolamine was examined as a nitrogen source in the production of hydrogen by Rhodobacter capsulatus ST-410, a hydrogenase-deficient mutant of the strain B-100. It was found that ethanolamine supports cell growth as the sole nitrogen source and permits a large amount of hydrogen evolution, detected at 138 μmol/ml- culture from 3.5 mM ethanolamine and 30 mM DL-malate. The amount corresponded to a stoichiometric yield of 77% and was close to that obtained from 7.0 mM L-glutamate and 30 mM DL-malate. The hydrogen evolution rate per unit biomass (cells) was higher than that with L-glutamate, and the cells grown with ethanolamine had higher nitrogenase activity than the cells grown with L-glutamate. In terms of bioconversion of cellulosic and hemicellulosic biomass to hydrogen, D-glucose, D-xylose, and D-cellobiose were tested as substrates. The results indicated that those sugars permit a large evolution of hydrogen through cultivation with ethanolamine as a nitrogen source. For instance, the cells grown with 3.5 mM ethanolamine evolved hydrogen of 289 μmol/ml-culture (80% yield) from 30 mM D-glucose under a controlled pH of 6.4 to 6.9.
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  • Hiroki OHARA, Shuichi KARITA, Tetsuya KIMURA, Kazuo SAKKA, Kunio OHMIY ...
    2000 Volume 64 Issue 2 Pages 254-260
    Published: 2000
    Released: March 03, 2005
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      The cellulolytic complex was isolated from the culture supernatant of Ruminococcus albus strain F-40 grown on cellulose by a Sephacryl S-300HR column chromatography. The molecular mass of the cellulolytic complex was found to be larger than 1.5×106 Da. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) analysis indicated that the cellulolytic complex contained at least 15 proteins with molecular weights from 40 kDa to 250 kDa. Among them, 11 proteins showed endoglucanase and/or xylanase activities on the zymograms. Immunological analysis using an antiserum raised against the dockerin domain of endoglucanase VII of R. albus (DocVII) suggested that at least 7 proteins in the cellulolytic complex contained a dockerin domain immunoreactive with the anti-DocVII antiserum. Furthermore, DocVII was shown to specifically interact with a 40-kDa protein of the cellulolytic complex by Far-Western blot analysis. These results strongly suggest that the cellulolytic complex produced by R. albus resembles the cellulosome specified for the cellulolytic complex of several clostridia such as Clostridium thermocellum and respective components are assembled into the cellulosome by the mechanism common in all of the cellulolytic clostridia, i.e., the cellulosome is formed by the interaction between a dockerin domain of catalytic components and a cohesin domain of a scaffolding protein.
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  • Myung-Hee KIM, Hyung-Kwoun KIM, Jung-Kee LEE, Sun-Yang PARK, Tae-Kwang ...
    2000 Volume 64 Issue 2 Pages 280-286
    Published: 2000
    Released: March 03, 2005
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      An efficient expression system was developed for the production of the thermostable lipase from Bacillus stearothermophilus L1 in an Escherichia coli system. A structural gene corresponding to mature lipase was subcloned in the pET-22b(+) expression vector and its expression was induced by IPTG at 30°C in E. coli cells. The lipase activity in a cell-free extract was as high as 448,000 units/g protein, which corresponds to as much as 26% of the total cellular protein and is 77 times higher than that of E. coli RR1/pLIP1. Based on its pI (7.4) and pH stability data reported previously, the L1 lipase was efficiently purified to homogeneity with CM (at pH 6.0) and DEAE (at pH 8.8) column chromatographies with a recovery yield of 62%. The specific activity of the purified enzyme was 1700 units/mg protein when olive oil emulsion was used as a substrate. Its optimum temperature for the hydrolysis of olive oil was 68°C and it was stable up to 55°C for 30 min-incubation. The thermostability increased by about 8-10 degrees in the presence of calcium ions. This calcium-dependent thermostability was confirmed by the tryptophan fluorescence emission kinetics showing that the enzyme starts to unfold at 66°C in the presence of calcium ions but at 58°C in the absence of calcium ions, implying that the calcium ions bind to the thermostable enzyme and stabilize the protein tertiary structure even at such high temperatures.
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  • Takanobu NAKAZAWA, Maki TAKAHASHI, Hiroyuki HORIUCHI, Akinori OHTA, Ma ...
    2000 Volume 64 Issue 2 Pages 369-377
    Published: 2000
    Released: March 03, 2005
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      Candida maltosa is a dimorphic fungus and its pseudohyphal growth is partly induced by additional copies of the centromeric DNA (CEN) region1) or n-alkane. In the course of analyzing the induction mechanism of pseudohyphal growth, we isolated EPD1, which is similar in sequence to PHR1 and PHR2 of Candida albicans. Epd1p could be involved in cell wall maintenance and is essential for pseudohyphal growth induced by CEN and n-hexadecane at pH 4 and by n-hexadecane at pH 7.2) In this paper, we cloned EPD2 of C. maltosa, which is highly similar to EPD1, PHR1, and PHR2. The transcription of EPD2 is induced strongly when cells are grown in SD medium of higher pH (pH 7), but not in SD medium of lower pH (pH 4). This pattern of expression was an inverse of that of EPD1. This alternate expression is similar to that between PHR1 and PHR2. The expression of EPD2 was much higher when C. maltosa was grown on the n-hexadecane solid medium than grown in the n-hexadecane liquid medium. The efficiency of pseudohyphal formation of an epd2 null mutant on n-hexadecane medium at pH 7 or 7.5 was lower than that of the wild-type strain. These results suggest that Epd2p is required for efficient pseudohyphal formation induced by n-hexadecane in the medium at pH 7.
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  • Kiyoshi OKUYAMA, Tomoki HAMAMOTO, Kazuya ISHIGE, Kenji TAKENOUCHI, Tos ...
    2000 Volume 64 Issue 2 Pages 386-392
    Published: 2000
    Released: March 03, 2005
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      Uridine 5′-diphospho-N-acetylglucosamine (UDP-GlcNAc) has been synthesized by a yeast-based method from 5′-UMP and glucosamine, in which yeast cells catalyze the conversion of 5′-UMP to 5′-UTP and provide enzymes involved in UDP-GlcNAc synthesis using 5′-UTP and glucosamine as substrates. However, this conventional method is not suitable for practical production of UDP-GlcNAc because of the low yield of the product. We found that the yqgR gene product of Bacillus subtilis, which has been identified as a glucokinase, can catalyze the phosphorylation of N-acetylglucosamine (GlcNAc) to give GlcNAc-6-phosphate, an intermediate of UDP-GlcNAc biosynthesis. The addition of the yqgR gene product to the yeast-based reaction system enabled us to synthesize UDP-GlcNAc using GlcNAc in place of glucosamine. The addition of two enzymes, GlcNAc-phosphate mutase and UDP-GlcNAc pyrophosphorylase, increased the yield of UDP-GlcNAc. Using this novel method, UDP-GlcNAc was produced at an amount of 78 mM from 100 mM 5′-UMP and 100 mM GlcNAc.
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  • Kenzo KOIKE, Mikio TAKAIWA, Katsutoshi ARA, Shigeo INOUE, Yoshiharu KI ...
    2000 Volume 64 Issue 2 Pages 399-404
    Published: 2000
    Released: March 03, 2005
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      Resting cells of a double mutant noted as KSM-MT66, derived from Rhodococcus sp. strain KSM-B-3 by UV irradiation, were found to cis-desaturate isopropyl hexadecanoate, yielding isopropyl cis-6-hexadecenoate. Addition of sodium glutamate (1.0%), MgSO4 (2 mM), and thiamine (2 mM) increased the productivity of the unsaturated product in phosphate buffer. Optimal temperature and pH for the reaction were around 26°C and 7, respectively. Under the optimized conditions, more than 50 g/l of isopropyl cis-6-hexadecenoate was produced after a 3-day incubation by resting cells of the mutant. Thus, cis-6-hexadecenoic acid, the main component of human sebaceous lipids, can be manufactured economically by the rhodococcal bioconversion.
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Microbiology & Fermentation Technology Notes
  • Tomoaki DEGUCHI, Makoto YOSHIMOTO, Riichiro OHBA, Seinosuke UEDA
    2000 Volume 64 Issue 2 Pages 414-416
    Published: 2000
    Released: March 03, 2005
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      The novel purple pigment hordeumin, an anthocyanin-tannin pigment, was produced from barley bran-fermented broth. The mutagenicity or antimutagenicity of hordeumin was investigated according to the Ames method, an indication of the safety of food, using Salmonella typhimurium TA98. Despite the presence of S-9 mix, hordeumin was not mutagenic. On the other hand, hordeumin effectively decreased a reverse mutation from Trp-P-1, Trp-P-2, IQ, and B[a]P. Furthermore, hordeumin also decreased the reverse mutation from dimethyl sulfoxide extracts of grilled beef.
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  • 2005 Volume 64 Issue 2 Pages E1
    Published: 2005
    Released: April 07, 2005
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    We regret to report the following errors on Vol. 64, No. 1 which were caused by our printer. Please correct the page numbers (pp. 173-190 and pp. 198-210) on the running head with the stickers provided. Wrong:Biosci. Biotechnol. Biochem., 63 (7), 173-177, 1999
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  • 2005 Volume 64 Issue 2 Pages E2
    Published: 2005
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    We regret to report the following errors on Vol. 64, No. 1 which were caused by our printer. Please correct the page numbers (pp. 173-190 and pp. 198-210) on the running head with the stickers provided. Wrong:Biosci. Biotechnol. Biochem., 63 (7), 178-180, 1999
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  • 2005 Volume 64 Issue 2 Pages E3
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    We regret to report the following errors on Vol. 64, No. 1 which were caused by our printer. Please correct the page numbers (pp. 173-190 and pp. 198-210) on the running head with the stickers provided. Wrong:Biosci. Biotechnol. Biochem., 63 (7), 181-183, 1999
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  • 2005 Volume 64 Issue 2 Pages E4
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    We regret to report the following errors on Vol. 64, No. 1 which were caused by our printer. Please correct the page numbers (pp. 173-190 and pp. 198-210) on the running head with the stickers provided. Wrong:Biosci. Biotechnol. Biochem., 63 (7), 184-186, 1999
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  • 2005 Volume 64 Issue 2 Pages E6
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  • 2005 Volume 64 Issue 2 Pages E7
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