Bioscience, Biotechnology, and Biochemistry
Online ISSN : 1347-6947
Print ISSN : 0916-8451
Volume 64 , Issue 4
Showing 1-46 articles out of 46 articles from the selected issue
Review
  • Eiji ICHISHIMA
    2000 Volume 64 Issue 4 Pages 675-688
    Published: 2000
    Released: March 01, 2005
    JOURNALS FREE ACCESS
      This review covers the unique catalytic and molecular properties of three proteolytic enzymes and a glycosidase from Aspergillus. An aspartic proteinase from A. saitoi, aspergillopepsin I (EC 3.4.23.18), favors hydrophobic amino acids at P1 and P1′ like gastric pepsin. However, aspergillopepsin I accommodates a Lys residue at P1, which leads to activation of trypsinogens like duodenum enteropeptidase. Substitution of Asp76 to Ser or Thr and deletion of Ser78, corresponding to the mammalian aspartic proteinases, cathepsin D and pepsin, caused drastic decreases in the activities towards substrates containing a basic amino acid residue at P1. In addition, the double mutant T77D/G78(S)G79 of porcine pepsin was able to activate bovine trypsinogen to trypsin by the selective cleavage of the K6-I7 bond of trypsinogen.
      Deuterolysin (EC 3.4.24.39) from A. oryzae, which contains 1 g atom of zinc/mol of enzyme, is a single chain of 177 amino acid residues, includes three disulfide bonds, and has a molecular mass of 19,018 Da. It was concluded that His128, His132, and Asp164 provide the Zn2+ ligands of the enzyme according to a 65Zn binding assay. Deuterolysin is a member of a family of metalloendopeptidases with a new zinc-binding motif, aspzincin, defined by the “HEXXH+D” motif and an aspartic acid as the third zinc ligand.
      Acid carboxypeptidase (EC 3.4.16.1) from A. saitoi is a glycoprotein that contains both N- and O-linked sugar chains. Site-directed mutagenesis of the cpdS, cDNA encoding A. saitoi carboxypeptidase, was cloned and expressed. A. saitoi carboxypeptidase indicated that Ser153, Asp357, and His436 residues were essential for the enzymic catalysis. The N-glycanase released high-mannose type oligosaccharides that were separated on HPLC. Two, which had unique structures of Man10GlcNAc2 and Man11GlcNAc2, were characterized.
      An acidic 1,2-α-mannosidase (EC 3.2.1.113) was isolated from the culture of A. saitoi. A highly efficient overexpression system of 1,2-α-mannosidase fusion gene (f-msdS) in A. oryzae was made. A yeast mutant capable of producing Man5GlcNAc2 human-compatible sugar chains on glycoproteins was constructed. An expression vector for 1,2-α-mannosidase with the “HDEL” endoplasmic reticulum retention/retrieval tag was designed and expressed in Saccharomyces cerevisiae. The first report of production of human-compatible high mannose-type (Man5GlcNAc2) sugar chains in S. cerevisiae was described.
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Organic Chemistry Regular Papers
  • Kazuo SOENO, Yoshimasa KYOKAWA, Masahiro NATSUME, Hiroshi ABE
    2000 Volume 64 Issue 4 Pages 702-709
    Published: 2000
    Released: March 01, 2005
    JOURNALS FREE ACCESS
      The new brassinosteroid conjugate, teasterone-3-O-β-D-glucopyranoside, was found as a metabolite of teasterone in lily cell suspension cultures. Its structure was determined by means of FAB-MS and 1H-NMR upon comparison with the authentic compound. Furthermore, its presence in lily anthers was confirmed by FAB-MS and LC-APCI-SIM data. This is the first natural brassinosteroid conjugate glucosylated at a hydroxyl group in ring A.
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  • Masato KATAYAMA
    2000 Volume 64 Issue 4 Pages 808-815
    Published: 2000
    Released: March 01, 2005
    JOURNALS FREE ACCESS
      4-Chloroindole-3-acetic acid (4-Cl-IAA) and its esters were synthesized from 2-chloro-6-nitrotoluene as the starting material. The biological activities of 4-Cl-IAA and its esters were determined by four bioassays. Except for the tert-butyl ester, 4-Cl-IAA and its esters had stronger elongation activity toward Avena coleoptiles than had indole-3-acetic acid. The biological activities of the methyl, ethyl and allyl esters were as strong as the activity of the free acid. All the esters, except for the tert-butyl, inhibited Chinese cabbage hypocotyl growth more than the free acid did, and all the esters induced severe swelling and formation of numerous lateral roots in black gram seedlings even at a low concentration. Furthermore, adventitious root formation was strongly promoted in Serissa japonica cuttings by all the esters. The root formation-promoting activities of the ethyl and allyl esters were about three times the value for indole-3-butyric acid which is used to promote and accelerate root formation in plant cuttings.
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Organic Chemistry Notes
Biochemistry & Molecular Biology Regular Papers
  • Hiroshi KITAGAKI, Shigeo TOMIOKA, Toshio YOSHIZAWA, Hiroyuki SORIMACHI ...
    2000 Volume 64 Issue 4 Pages 689-695
    Published: 2000
    Released: March 01, 2005
    JOURNALS FREE ACCESS
      Calpain, a calcium dependent cysteine protease, consists of a catalytic large subunit and a regulatory small subunit. Two models have been proposed to explain calpain activation: an autolysis model and a dissociation model. In the autolysis model, the autolyzed form is the active species, which is sensitized to Ca2+. In the dissociation model, dissociated large subunit is the active species. We have reported that the Ca2+ concentration regulates reversible dissociation of subunits. We found further that in chicken μ/m-calpain autolysis of the large subunit induces irreversible dissociation from the small subunit as well as activation. So we could propose a new mechanism for activation of the calpain by combining our findings. Our model insists that autolyzed large subunit remains dissociated from the small subunit even after the removal of Ca2+ to keep it sensitized to Ca2+. This model could be expanded to other calpains and give a new perspective on calpain activation.
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  • Tetsuya MASUDA, Kyoden YASUMOTO, Naofumi KITABATAKE
    2000 Volume 64 Issue 4 Pages 710-716
    Published: 2000
    Released: March 01, 2005
    JOURNALS FREE ACCESS
      Two types of conformationally specific anti-irradiated ovalbumin monoclonal antibodies were prepared in order to study and monitor irradiation-induced structural changes in the ovalbumin molecule. Surface plasmon resonance (SPR) detection was used to investigate the kinetic parameters of the reaction between antibodies and ovalbumin which had been administered with different doses of irradiation (0, 1.5, 2.0, 5.0, 10, 20, 50, and 100 kGy). The results demonstrate that the combination of monoclonal antibodies and the SPR method can be used to characterize the irradiation-induced conformational change with an unlabelled reagent.
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  • Tomoyoshi KOYANAGI, Kiyoyuki MATSUMURA, Shun’ichi KURODA, Katsuy ...
    2000 Volume 64 Issue 4 Pages 717-722
    Published: 2000
    Released: March 01, 2005
    JOURNALS FREE ACCESS
      The cDNA coding for copper amine oxidase has been cloned from etiolated pea seedlings (Pisum sativum). The deduced amino acid sequence, consisting of 674 residues including the signal peptide, agreed well with those reported for the enzymes from a different cultivar of P. sativum and other plant sources, except for several evolutionary replacements located mostly on the molecular surface. A heterologous expression system for the cloned pea enzyme was constructed with the yeast Pichia pastoris, using the AOX1 promoter and the yeast α-factor secretion signal. Adding copper to the culture medium increased the secretion of an active, quinone-containing enzyme. Furthermore, the inactive enzyme produced in a copper-deficient medium was activated considerably by subsequent incubation with excess cupric ions. These results strongly suggest that the Tyr-derived redox cofactor, 2,4,5-trihydroxyphenylalanylquinone (topa quinone, TPQ), is produced in the plant enzyme by post-translational modification that proceeds through the copper-dependent, self-processing mechanism, as in the enzymes from bacteria and yeast.
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  • Yasuyuki ARAKANE, Hironori HOSHIKA, Natsumi KAWASHIMA, Chika FUJIYA-TS ...
    2000 Volume 64 Issue 4 Pages 723-730
    Published: 2000
    Released: March 01, 2005
    JOURNALS FREE ACCESS
      To evaluate the anti-pathogen activity of chitinases, we developed a new method for measuring the lytic activity, and investigated the correlation of the lytic activity with the enzymatic properties by using four chitinase isozymes, Chitinases E, F, H1 and G, which had been purified from yam tubers by column chromatography. Chitinases E, F and H1 had high lytic activity against the plant pathogen, Fusarium oxysporum, but Chitinase G did not. Chitinase E, which is the family 19 chitinase, was similar to Chitinases F and G in its antigenecity, but not to Chitinase H1 or H2. Chitinases H1 and H2 were recognized by the anti-Bombyx mori chitinase antibody, suggesting that Chitinases H1 and H2 are family 18 chitinases like B. mori chitinases. Chitinases E, F and H1 had two optimum pH ranges of 3-4 and 7.5-9 toward glycolchitin, but Chitinase G had only one optimum pH value of 5. Chitinases E, F and H1 had higher affinity to the polymer substrate, glycolchitin, than Chitinase G. These results suggest that the lytic activity of plant chitinases may be related to the chitin affinity and probably to the characteristic optimum pH value, or two values, but not related to its classification. The correlation of the lytic activity of a chitinase isozyme with its elicitor specificity is also discussed.
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  • Noriko AJISAKA, Koji HARA, Katsuhiko MIKUNI, Kozo HARA, Hitoshi HASHIM ...
    2000 Volume 64 Issue 4 Pages 731-734
    Published: 2000
    Released: March 01, 2005
    JOURNALS FREE ACCESS
      In order to investigate the application potential of branched CDs, the solubilizing ability and the stabilizing ability of G2-βCD and GUG-βCD were investigated by using twelve terpenes (d-limonene, myrcene, terpinolene, geraniol, l-menthol, nerol, α-terpineol, citral, d-citronellal, l-perillaldehyde, (R)-l-carvone, and menthone) as guest compounds. G2-βCD and GUG-βCD showed more solubilizing ability for these twelve terpenes than βCD, and the ability of GUG-βCD was almost the same as that of G2-βCD. The stabilizing ability of terpene-GUG-βCD complexes was different from that of G2-βCD. GUG-βCD was superior to G2-βCD, especially in the solid state. This result may have been caused by the difference in structure of side chain, namely the hydroxymethyl group in G2-βCD and the carboxyl group in GUG-βCD.
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  • Hirofumi NAKANO, Motohiro SHIZUMA, Taro KISO, Sumio KITAHATA
    2000 Volume 64 Issue 4 Pages 735-740
    Published: 2000
    Released: March 01, 2005
    JOURNALS FREE ACCESS
      β-Galactosidase catalyzed β-galactosylation not only of a hydroxyl group but also of a thiol group in the condensation reaction of D-galactose and 2-mercaptoethanol. The thio-galactosylation product was confirmed as 2-hydroxyethyl S-β-D-galactoside on the bases of fast atom bombardment mass spectrometry, infrared spectroscopy, and nuclear magnetic resonance spectorometry. Aspergillus oryzae β-galactosidase hydrolyzed p-nitrophenyl S-β-D-galactoside most rapidly among several β-galactosidases and produced the thio-galactosylation product most efficiently. The Penicillim multicolor enzyme was as effective as the A. oryzae enzyme. However the enzymes from Escherichia coli, Saccharomyces fragilis, Kluyveromyces lactis, and Bacillus circulans galactosylated hydroxyl groups predominantly to produce O-galactoside. The thio-galactoside was synthesized most effectively at a 2-mercaptoethanol concentration of about 1.25 M. Galactose concentration at 0.8-2.8 M did not affect the synthetic yield of the thio-galactoside so greatly.
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  • Satoshi KANEKO, Motomitsu KITAOKA, Atsushi KUNO, Kiyoshi HAYASHI
    2000 Volume 64 Issue 4 Pages 741-745
    Published: 2000
    Released: March 01, 2005
    JOURNALS FREE ACCESS
      4-Methylumbelliferyl-β-D-xylobioside (MU-X2) and 5-bromo-3-indolyl-β-D-xylobioside (BI-X2) were synthesized as substrates for the detection of xylanase activity on agar plates. A family F/10 xylanase from Streptomyces olivaceoviridis E-86 (FXYN) was able to be more sensitively detected than RBB-xylan by using MU-X2 as a substrate. A mutant xylanase E128H/FXYN having only 1/1000 of the activity of FXYN was also able to be detected on the MU-X2 plate but was not detected on the RBB-xylan plate. A family G/11 xylanase from Streptomyces lividans 66 (Xyn B) was not detected on the MU-X2 plate, but it was able to be detected on the RBB-xylan plate, suggesting that the MU-X2 substrate is specific to family F/10 xylanases. However, none of the xylanases were detected effectively by using BI-X2 as a substrate.
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  • Yuichi NODAKE, Nobuyuki YAMASAKI
    2000 Volume 64 Issue 4 Pages 767-774
    Published: 2000
    Released: March 01, 2005
    JOURNALS FREE ACCESS
      Hen egg-white lysozyme was modified with a succinyl ester derivative of monomethoxypolyethylene glycol (mPEG-COONSu), and some properties of the resulting conjugate (mPEG-lysozyme) were studied. The conjugate was prepared by modification of lysozyme with mPEG-COONSu and purified with use of columns of CM-Toyopearl 650M and Sephadex G-75. Analytical data indicated that in the conjugate, 1.05 moles of mPEG with an average molecular weight of 5,000 were covalently attached to the lysozyme molecule. Tryptic peptide analysis of the conjugate showed that Lys 33 in lysozyme is the residue mainly modified with mPEG-COONSu. Covalent attachment of the mPEG-derivative to amino groups greatly increased the thermostability of lysozyme without any conformational change of the protein molecule. mPEG-lysozyme retained full enzyme activity for glycol chitin, but lytic activity for Micrococcus luteus cells in neutral media was 75% of that of native lysozyme and its optimal pH was at pH 5.0. It was also found that the reactivity of lysozyme with anti-lysozyme antibody from BALB/c mice or human lymphocytes was decreased by modification with mPEG-COONSu. From these findings, it was suggested that mPEG-COONSu can be advantageously used for protein tailoring of lysozyme.
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  • Yutaka SHOJI, Mamoru ISEMURA, Haruhiko MUTO, Satoko ISEMURA, Yutaka AO ...
    2000 Volume 64 Issue 4 Pages 775-780
    Published: 2000
    Released: March 01, 2005
    JOURNALS FREE ACCESS
      A type IV collagen-binding protein of 41 kDa was isolated from the mushroom Hypsizigus marmoreus and the protein was designated as HM41. The Western blotting analysis with anti-HM41 antibodies demonstrated that HM41 was unrelated to HM23, which had been shown to have an affinity for type IV collagen. The microsequence analysis of the membrane-blotted peptides generated by fragmentation with cyanogen bromide showed no homologous proteins reported. HM41 had cell adhesion-promoting activity for murine Lewis lung carcinoma LL2 cells and human fibrosarcoma HT1080 cells. These results indicate that HM41 is a hitherto undescribed fungus protein that can interact both with animal extracellular matrix protein type IV collagen and with animal tumor cells.
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  • Hiroyuki NAGAOKA, Hiroshi KAYAHARA
    2000 Volume 64 Issue 4 Pages 781-784
    Published: 2000
    Released: March 01, 2005
    JOURNALS FREE ACCESS
      Kinetic resolution of racemic alcohols, (±)-1-(4-substituted phenyl)ethanol and (±)-1-(2-naphthyl)ethanol, was done with immobilized green pea, soybean, or buckwheat proteins. The resolution was done stereoselectively by oxidizing only one enantiomer of a racemic alcohol to leave an optically active alcohol with a high purity. In addition, each protein could be reused consecutively at least three times without any decrease of yield or optical purity.
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  • Use of a Polyacrylamide Derivative with GlcNAc-β Side Chains as a Solid Phase Acceptor Substrate
    Mohamed OUBIHI, Kenji OSHIMA, Naohito AOKI, Kazukiyo KOBAYASHI, Ken KI ...
    2000 Volume 64 Issue 4 Pages 785-792
    Published: 2000
    Released: March 01, 2005
    JOURNALS FREE ACCESS
      In our previous paper [Oubihi et al. (1998) Anal. Biochem., 257, 169-175], we have shown that a polyacrylamide-derived synthetic glycopolymer with GlcNAcβ side chains, termed PAP(GlcNAcβ), is useful as a solid phase acceptor substrate for the ELISA-based analyses of soluble β1,4(-)galactosyltransferase (GalT) activity in milk. This method is now used to assay detergent-solubilized cellular GalT. The glycopolymer coated on polystyrene plates was shown to be highly stable against the non-ionic and ionic detergents tested (0~5% solutions of Triton X-100 and SDS). Such stability made it possible to incubate the ELISA plate with detergent-solubilized GalT and to wash the ELISA plate with SDS solution after the GalT reaction, leading to high accuracy and sensitivity of this assay. The GalT activity was assayed using this method for 1% Triton X-100 extracts of various tissue samples of mice and several cultured cell lines. The results showed that the specific GalT activity of tissue extracts was low in brain and intestine, and high in ovary, muscle, and kidney. As for the cultured cell lines, COS7, COMMA-1D and C2C12 cells showed high specific activity, while CHO and MDCK cells showed low activity. The myoblast C2C12 had a slight increase in GalT activity during starvation-induced cell differentiation. On the other hand, GalT-I transcript estimated by RT-PCR rather decreased during C2C12 cell differentiation, suggesting a differentiation-dependent switch in GalT isozymes. Taken all together, the ELISA-based assay using PAP(GlcNAcβ) as a solid phase acceptor substrate was demonstrated to be a useful method for the assay of membrane-bound galactosyltransferases.
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  • Yuko ISHII, Hisami YAMADA, Takafumi YAMASHINO, Kenji OHASHI, Etsuko KA ...
    2000 Volume 64 Issue 4 Pages 799-807
    Published: 2000
    Released: March 01, 2005
    JOURNALS FREE ACCESS
      The Escherichia coli yhhP gene was predicted to encode a small hypothetical protein of 81 amino acids, the cellular function of which is not known. To gain insight into the function of this uncharacterized YhhP protein, genetic and biochemical studies were done. We first tried to express and purify the YhhP protein to prepare an anti-YhhP antiserum. Western blotting showed that the hypothetical yhhP gene is indeed transcribed and translated as a minor cytoplasmic protein. YhhP-deficient (ΔyhhP) cells formed colonies poorly on a rich medium (e.g., Luria-Bertani medium) containing a relatively low concentration of NaCl, while they can grow normally either in LB containing 3% NaCl or in a synthetic medium (e.g., M9-glucose). During exponential growth in rich medium, an early step of cell division was inhibited in ΔyhhP cells, forming filaments. For the YhhP-deficient filamentous cells, the FtsZ-ring formation was analyzed with immunofluorescence microscopy. The FtsZ-ring formation did not occur normally in the ΔyhhP filaments, although the filamentous cells contained the FtsZ protein at a certain level comparable to that in the wild-type cells. The ftsZ gene was found to function as a multicopy suppressor of the ΔyhhP mutant. Another multicopy suppressor gene was identified as the dksA gene. Provided that either the ftsZ or dksA gene was introduced into the mutant cells with its multicopy state, the resulting transformants were capable of growing in rich medium, formed wild-type short rods. These results are discussed with regard to the presumed function of this ubiquitous protein.
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  • Katsuya GOMI, Terumi AKENO, Toshitaka MINETOKI, Kenji OZEKI, Chieko KU ...
    2000 Volume 64 Issue 4 Pages 816-827
    Published: 2000
    Released: March 01, 2005
    JOURNALS FREE ACCESS
      A gene, designated amyR, coding for a transcriptional activator involved in amylolytic gene expression has been cloned from Aspergillus oryzae by screening for a clone that enabled to reverse the reduced expression of the α-amylase gene (amyB) promoter. amyR encodes 604 amino acid residues of a putative DNA-binding protein carrying a zinc binuclear cluster motif (Zn(II)2Cys6) belonging to the GAL4 family of transcription factors. The amyR gene disruptants showed a significant restricted growth on starch medium and produced little of the amylolytic enzymes including α-amylase and glucoamylase compared with a non-disruptant, indicating that amyR is a transcriptional activator gene involved in starch/maltose-induced efficient expression of the amylolytic genes in A. oryzae. In addition, sequencing analysis found that amyR, agdA (encoding α-glucosidase), and amyA (encoding α-amylase), are clustered on a 12-kb DNA fragment of the largest chromosome in A. oryzae, and that amyR is about 1.5 kb upstream of agdA and transcribed in the opposite direction. Furthermore, transcriptional analysis revealed that the amyR gene was expressed in the presence of glucose comparable to the level in the presence of maltose, while the amylolytic genes were transcribed at high levels only in the presence of maltose.
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  • Janet SIM, Tiow-Suan SIM
    2000 Volume 64 Issue 4 Pages 828-832
    Published: 2000
    Released: March 01, 2005
    JOURNALS FREE ACCESS
      Deacetoxycephalosporin C synthase (DAOCS) is a non-heme iron-binding and α-ketoglutarate dependent enzyme involved in catalyzing the biosynthesis of cephalosporins and cephamycins, antibiotics more potent than penicillins. In the crystal structure complex of Streptomyces clavuligerus DAOCS (scDAOCS), it was proposed that histidine-183, aspartate-185, and histidine-243 are putative iron-binding ligands. However, coordinates proposed for crystal structures of proteins may not definitely comply with catalysis. Hence, site-directed mutagenesis was done to replace each of these amino acid residues with leucine. The constructed expression vectors bearing the mutations were found to express the respective scDAOCS mutant enzymes at high levels in Escherichia coli BL21(DE3). Through enzymatic assays, it was shown that while the wildtype enzyme could convert penicillin to a more active cephalosporin, the substitution of the three proposed iron-binding sites of scDAOCS completely abolished the same activity in the respective mutant enzymes. Thus, these results clearly indicate that histidine-183, aspartate-185, and histidine-243 of scDAOCS are essential for the ring expansion activity.
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Biochemistry & Molecular Biology Notes
Food & Nutrition Science Regular Papers
  • Soon-Young KIM, Dong-Hwa SHON, Ke-Ho LEE
    2000 Volume 64 Issue 4 Pages 696-701
    Published: 2000
    Released: March 01, 2005
    JOURNALS FREE ACCESS
      In order to detect chitooligosaccharides (COS), an enzyme-linked immunosorbent assay (ELISA) was developed. A chitooligosaccharide mixture (COSM) conjugated to bovine serum albumin was used to immunize rabbits to produce an anti-COS polyclonal antibody. By use of specific antibody and COSM-horseradish peroxidase conjugate, we established a competitive direct ELISA (cdELISA) the detection limit of which was about 0.1 μg/ml. In the cdELISA, the cross-reactivities of the specific antibody toward glucosamine, chitobiose, chitotriose, chitotetraose, chitopentaose, and chitohexaose were 0.27, 27, 75, 75, 144, and 100%, respectively, and those toward N-acetylchitobiose, N-acetylchitotriose, N-acetylchitotetraose, N-acetylchitopentaose, and N-acetylchitohexaose were 1.58, 0.005, 1.08, 0.05, and 0.40%, respectively.
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  • Octavio CARVAJAL, Masanobu SAKONO, Hirofumi SONOKI, Masahiro NAKAYAMA, ...
    2000 Volume 64 Issue 4 Pages 793-798
    Published: 2000
    Released: March 01, 2005
    JOURNALS FREE ACCESS
      A study was carried out to examine if the positional distribution of medium chain fatty acids (MCF) in triacylglycerol influences dietary fat absorption in rats. Two types of structure-specific fats, one predominantly composed of MCF in sn-1(3) and linoleic acid in sn-2 [sn-1(3)MCF-structured] and the others of MCF in sn-2 and linoleic acid in sn-1(3) [sn-2MCF-structured], were initially prepared, and the two structure-specific fats were interesterified and designated as sn-1(3)MCF-interesterified and sn-2MCF-interesterified. Synthetic fat was mixed with an equal amount of cocoa butter (103 g/kg of diet) and was supplemented to the AIN93G-based diet. Rats were fed on the diets for 4 wk. Long-chain saturated fatty acids were the predominant fatty acids excreted into the feces, and the positional distribution of MCF resulted in an altered fat absorption rate (%) of 81.8, 82.5, 84.2 and 86.3 for the rats fed on the diets containing sn-2MCF-structured, sn-1(3)MCF-interesterified, sn-2MCF-interesterified and sn-1(3)MCF-structured fats, respectively. The proportion of MCF in the serum, liver and adipose tissue triacylglycerols was not affected by the MCF distribution of the dietary fats. These results indicate that the distribution of MCF in dietary triacylglycerol is a determinant of intestinal fat absorption.
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Food & Nutrition Science Notes
Microbiology & Fermentation Technology Regular Papers
  • Takeshi SHIBASAKI, Hideo MORI, Akio OZAKI
    2000 Volume 64 Issue 4 Pages 746-750
    Published: 2000
    Released: March 01, 2005
    JOURNALS FREE ACCESS
      A proline 4-hydroxylase gene, which was cloned from Dactylosporangium sp. RH1, was overexpressed in Escherichia coli W1485 on a plasmid under a tryptophan tandem promoter after the codon usage of the 5′ end of the gene was optimized. The proline 4-hydroxylase activity was1600-fold higher than that in Dactylosporangium sp. RH1. trans-4-Hydroxy-L-proline(Hyp) was produced and accumulated to 41 g/L (87% yield from L-proline) in 100 h when the recombinant E. coli was cultivated in a medium containing L-proline and glucose. 2-Oxoglutarate, which is necessary for the hydroxylation of L-proline by proline 4-hydroxylase, was apparently supplied from glucose through the cellular metabolic pathway. The putA mutant of W1485, which is not able to degrade L-proline, has allowed the quantitative conversion of L-proline to Hyp. The formation of other isomers of hydroxyproline was not observed. Productivity of Hyp was almost the same in a larger-scale culture. The method of manufacturing Hyp from L-proline was established.
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  • Tomoko EGUCHI, Katsumi DOI, Kanako NISHIYAMA, Sadahiro OHMOMO, Seiya O ...
    2000 Volume 64 Issue 4 Pages 751-756
    Published: 2000
    Released: March 01, 2005
    JOURNALS FREE ACCESS
      Phage contamination has resulted in abnormal fermentation in silage. We isolated a phage-resistant strain, Lactobacillus plantarum NGRI0101 from silage. The strain carried two plasmids, pLKL (6.8 kb) and pLKS (2.0 kb). By curing and retransformation of the plasmids, we clarified that pLKS has phage resistant activity, characterized as no adsorption inhibition. pLKS has 2,025 bp and three orfs, orf123, orf132, and orf918. The predicted amino acid sequence of the orf918 product showed high similarity to those of Rep proteins of Pediococcus halophilus plasmid pUCL287 and Lactobacillus acidophilus plasmid pLA103. The replication origin (ori) was upstream from orf918. There was no gene similar to typical phage resistant genes encoded by known plasmids. The phage resistance of L. plantarum NGRI0101 may possibly be due to a plasmid-encoded abortive infection.
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  • Machiko TANAKA, Shuichiro MURAKAMI, Ryu SHINKE, Kenji AOKI
    2000 Volume 64 Issue 4 Pages 757-760
    Published: 2000
    Released: March 01, 2005
    JOURNALS FREE ACCESS
      Gluconacetobacter xylinus (=Acetobacter xylinum) shows variety in acid formation from sugars and sugar-alcohols. Toyosaki et al. proposed new subspecies of G. xylinus (=Acetobacter xylinum) subsp. sucrofermentans in point of acid formation from sucrose and a homology index of 58.2% with the type strain of G. xylinus subsp. xylinus in DNA-DNA hybridization experiments. We tried DNA-DNA hybridization to clarify relationship between acid formation from sugars and classification of G. xylinus. The G+C contents of G. xylinus showed 60.1-62.4 mol% with a range of 2.3 mol%. When type strains of G. xylinus subsp. xylinus, G. xylinus subsp. sucrofermentans, and IFO 3288 forming acid from sucrose, were used as probes, the DNAs from three strains showed 67-100%, 64-89%, and 60-100% similarity to those from sixteen strains including bacteria that form acid from sucrose or not. These results show that homology indexes do not reflect differences of acid formation from sucrose. As a results, the species G. xylinus was proved to be genetically homogeneous.
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  • Hisashi KAWASAKI, Yoshihiro USUDA, Megumi SHIMAOKA, Takashi UTAGAWA
    2000 Volume 64 Issue 4 Pages 761-766
    Published: 2000
    Released: March 01, 2005
    JOURNALS FREE ACCESS
      An improved assay was developed to detect direct purine nucleoside phosphorylating activity in cell-free extracts. Direct inosine phosphorylating activity was detected in 2 of 70 species tested. Both activities, which depended on magnesium ion and ATP, phosphorylated a hydroxyl group at the 5′ position of inosine. The new assay was shown to be useful for screening of direct purine nucleoside phosphorylating activity and have the potential to detect inosine kinase in the presence of a background of nucleoside phosphorylase and purine phosphoribosyltransferase activities. Previously, the latter two activities made it difficult to correctly detect direct phosphorylation of inosine by inosine kinase.
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Microbiology & Fermentation Technology Notes
  • Kihachiro OGAWA, Naoto YOSHIDA, Wanwilai GESNARA, Crispinus A. OMUMASA ...
    2000 Volume 64 Issue 4 Pages 833-836
    Published: 2000
    Released: March 01, 2005
    JOURNALS FREE ACCESS
      A diploid strain obtained from heterokaryons of Trichoderma harzianum by protoplast fusion grew on minimal medium containing 100 ppm benomyl. This strain inhibited the growth of the phytopathogenic fungus Fusarium oxysporum f. sp. raphani on paired cultures and also protected against radish yellows and a drop in germination induced by F. oxysporum f. sp. raphani.
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  • Yoshihiro NAKAMURA, Hiroshi FUKUHARA, Konosuke SANO
    2000 Volume 64 Issue 4 Pages 841-844
    Published: 2000
    Released: March 01, 2005
    JOURNALS FREE ACCESS
      The enzyme phytase dephosphorylates phytin (inositol hexaphosphate), a major phosphate reserve in plants. We found that a large number of yeast species secreted a phytase. Several species were identified as high phytase producers. The yeast enzymes had an optimal activity at pH 4-5 and generally a very high optimal temperature, ranging from 60°C to 80°C.
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  • Mutsuko KUKIMOTO, Makoto NISHIYAMA, Masaru TANOKURA, Sueharu HORINOUCH ...
    2000 Volume 64 Issue 4 Pages 852-857
    Published: 2000
    Released: March 01, 2005
    JOURNALS FREE ACCESS
      norB and norC encoding the cytochrome b-containing subunit and the cytochrome c-containing subunit, respectively, of the nitric oxide reductase (NOR) in Alcaligenes faecalis S-6 were cloned and sequenced. Both NorB and NorC showed more than 40% sequence identity to the corresponding subunits of cytochrome bc-type NORs in other denitrifying bacteria. norCB was in a gene cluster containing seven other genes; these were named dnr, orf2, orf3, norE, norF, norQ, and norD on the basis of their similarity with NOR systems in other bacteria. Potential FNR-binding sites were present in front of norCB, norEF, and/or orf2/orf3, suggesting that most of these genes are regulated simultaneously by an FNR-related protein. NorB and NorC proteins produced in the membrane fraction in Escherichia coli showed no enzyme activity, probably due to lack of NorQ and NorD, which appear to perform some essential function for activation of the NorB-NorC complex in the recombinant E. coli.
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