Bioscience, Biotechnology, and Biochemistry
Online ISSN : 1347-6947
Print ISSN : 0916-8451
64 巻, 3 号
選択された号の論文の39件中1~39を表示しています
Organic Chemistry Regular Papers
Organic Chemistry Notes
Biochemistry & Molecular Biology Regular Papers
  • Sujata M. KHOPDE, K. Indira PRIYADARSINI, Shambhu Nath GUHA, Jagganath ...
    2000 年 64 巻 3 号 p. 503-509
    発行日: 2000年
    公開日: 2005/03/02
    ジャーナル フリー
      The antioxidant property of tetrahydrocurcumin (THC), a reduced derivative of curcumin, was examined by its ability to inhibit radiation-induced lipid peroxidation in rat liver microsomes and compared with curcumin. The lipid peroxidation caused by irradiation of N2O-purged and aerated buffered aqueous solutions was found to be inhibited by THC in a dose- and concentration-dependent manner. In order to understand the actual reaction mechanisms involved in the inhibition process, pulse radiolysis investigation of THC with radiolytically produced radicals like hydroxyl, model peroxyl radicals, and azide radicals were done and the transients were detected by kinetic spectrophotometry. The reaction of THC with hydroxyl and azide radicals gave rise to transient absorption in the region 200-400 nm with two peaks at 310 nm and 390 nm. From the spectral properties and kinetics of these radicals, a suitable mechanism is discussed to explain the antioxidant actions of THC.
  • Shin OGATA, Katsuzumi OKUMURA, Hiroshi TAGUCHI
    2000 年 64 巻 3 号 p. 510-515
    発行日: 2000年
    公開日: 2005/03/02
    ジャーナル フリー
      Measurement of poly(ADP-ribose) levels was performed by a new method using a monoclonal antibody against poly(ADP-ribose) and flow cytometry from small amount of cultured cells without the need for isolation of poly(ADP-ribose) polymer. The increase of poly(ADP-ribose)-associated fluorescence intensity was observed in individual human leukemic HL-60 cells when treated with the carcinogen, N-methyl-N′-nitro-N-nitrosoguanidine (MNNG), and was blocked by the treatment with 3-aminobenzamide before MNNG treatment. It is easy and rapid to detect the time-dependent change of poly(ADP-ribose) levels in HL-60 cells after MNNG treatment. We easily found that the increase of the poly(ADP-ribose) level in nicotinic acid-treated lymphocytes after MNNG treatment was observed, but not in nicotinamide-treated lymphocytes. We investigated the change of poly(ADP-ribose) levels especially in the early phase of apoptosis. Our method is simple and rapid. It is suggested that the investigation of poly(ADP-ribosyl)ation in various fields is possible by using this new method.
  • Hyun Min KOO, Seok-Won YIM, Chang-Seung LEE, Yu Ryang PYUN, Yu Sam KIM
    2000 年 64 巻 3 号 p. 523-529
    発行日: 2000年
    公開日: 2005/03/02
    ジャーナル フリー
      A UDP-glucose pyrophosphorylase (UGPase) gene from Acetobacter xylinum BRC5 has been cloned, sequenced, and expressed in Escherichia coli. The gene consists of 867 nucleotides and encodes a polypeptide of 289 amino acid residues with a calculated molecular mass of 31,493 Da. The amino acid sequences of the enzyme showed an 85.8% identity to those of an enzyme from A. xilinum ATCC 23768. A polyhistidine-UGPase fusion enzyme was expressed and purified from the transformed E. coli. The enzyme showed a 35,620-Da single protein band on SDS/PAGE and an about 160,000-Da protein band on 8-16% pore-gradient polyacrylamide gel, indicating the enzyme may be a tetramer or pentamer composed of four or five identical subunits. Kinetic analysis of the enzyme showed a typical Michaelis-Menten substrate saturation pattern, from which Km and Vmax were calculated to be 3.22 mM and 175.4 μmol•min-1•mg-1 for UDP-glucose and 0.24 mM and 69.4 μmol•min-1•mg-1 for PPi, respectively, required Mg2+ for maximal activity, and was inhibited by free pyrophosphate. Computer-aided comparison of the Acetobacter enzyme sequence with those of other bacterial enzymes found significant similarities among them and predicted that Lys84 is a catalytically important residue. Lys84 in the enzyme, which was also conserved in other bacterial enzyme sequences, was replaced by arginine or leucine. The K84R mutant enzyme was successfully expressed in E. coli and showed enzyme activity (63% of the wild-type enzyme activity), but K84L was not isolated in stable form. These results suggest that Lys84 is significant in not only catalysis but also maintenance of the active structure.
  • Yoshinobu KIMURA, Sayuri MATSUO
    2000 年 64 巻 3 号 p. 562-568
    発行日: 2000年
    公開日: 2005/03/02
    ジャーナル フリー
      Structural changes in N-linked oligosaccharides of glycoproteins during seed development of Ginkgo biloba have been explored to discover possible endogenous substrate(s) for the Ginko endo-β-N-acetylglucosaminidase (endo-GB; Kimura, Y., et al. (1998) Biosci. Biotechnol. Biochem., 62, 253-261), which should be involved in the production of high-mannose type free N-glycans.
      The structural analysis of the pyridylaminated oligosaccharides with a 2D sugar chain map, by ESI-MS/MS spectroscopy, showed that all N-glycans expressed on glycoproteins through the developmental stage of the Ginkgo seeds have the xylose-containing type (GlcNAc2~0Man3Xyl1Fuc1~0GlcNAc2) but no high-mannose type structure. Man3Xyl1Fuc1GlcNAc2, a typical plant complex type structure especially found in vacuolar glycoproteins, was a dominant structure through the seed development, while the amount of expression of GlcNAc2Man3Xyl1Fuc1GlcNAc2 and GlcNAc1Man3Xyl1Fuc1GlcNAc2 decreased as the seeds developed. The dominantly occurrence of xylose-containing type structures and the absence of the high-mannose type structures on Ginkgo glycoproteins were also shown by lectin-blotting and immunoblotting of SDS-soluble glycoproteins extracted from the developing seeds at various developmental stages.
      Concerning the endogenous substrates for plant endo-β-N-acetylglucosaminidase, these results suggested that the endogenous substrates might be the dolicol-oligosaccharide intermediates or some glycopeptides with the high-mannose type N-glycan(s) derived from misfolded glycoproteins in the quality control system for newly synthesized glycoproteins.
  • Kazuhisa HATAKEYAMA, Makoto GOTO, Yasukazu UCHIDA, Miki KOBAYASHI, Mas ...
    2000 年 64 巻 3 号 p. 569-576
    発行日: 2000年
    公開日: 2005/03/02
    ジャーナル フリー
      Several strains of thermophilic bacteria containing maleate cis-trans isomerase were isolated from soil samples and identified as Bacillus stearothermophilus, Bacillus circulans, Bacillus brevis, and Deleya halophila. The maleate cis-trans isomerase was purified and characterized from one of the isolated strains, B. stearothermophilus MI-102. The purified enzyme of strain MI-102 showed higher thermal stability than the enzyme of a mesophile, Alcaligenes faecalis IFO13111. The seven maleate cis-trans isomerase genes (maiA) of thermophile were cloned and sequenced. B. stearothemophilus MI-102 MaiA has 67% amino acid identity with A. faecalis MaiA. All eight amino acid sequences of maiA gene products had significant conserved regions containing cysteine residues, which were previously suggested to be involved in an active site of the enzyme. To probe the catalytic mechanism, three cysteine residues in the conserved regions of A. faecalis MaiA were replaced with serine by site-directed mutagenesis. The results suggest that Cys80 and Cys198 play important roles in the enzyme activity.
  • Yumiko NAKAZATO, Shigeru TAMOGAMI, Hiroshi KAWAI, Morifumi HASEGAWA, O ...
    2000 年 64 巻 3 号 p. 577-583
    発行日: 2000年
    公開日: 2005/03/02
    ジャーナル フリー
      The application of methionine on wounded rice leaves induced the production of rice phytoalexins, sakuranetin and momilactone A. This induction resulted from stimulation of phenylalanine ammonia-lyase and naringenin 7-O-methyltransferase activity. Jasmonic acid, ethylene, and active oxygen species are important as signal transducers in disease resistance mechanisms. However, although the endogenous level of jasmonic acid rapidly increased in reaction to wound, methionine treatment could not induced endogenous JA production. Ethylene induced the production of the flavonoid phytoalexin, sakuranetin, but did not induce the production of a terpenoid phytoalexin, momilactone A. On the other hand, a free radical scavenger, Tiron, counteracted the induction of both sakuranetin and momilactone A production in methionine-treated leaves. Active oxygen species may be important in methionine-induced production of phytoalexins.
Biochemistry & Molecular Biology Notes
Biochemistry & Molecular Biology Preliminary Communication
  • Tokuki SAKIYAMA, Hideto TAKAMI, Naotake OGASAWARA, Satoru KUHARA, Toki ...
    2000 年 64 巻 3 号 p. 670-673
    発行日: 2000年
    公開日: 2005/03/02
    ジャーナル フリー
      We developed a semi-automated genome analysis system called GAMBLER in order to support the current whole-genome sequencing project focusing on alkaliphilic Bacillus halodurans C-125. GAMBLER was designed to reduce the human intervention required and to reduce the complications in annotating thousands of ORFs in the microbial genome. GAMBLER automates three major routines: analyzing assembly results provided by genome assembler software, assigning ORFs, and homology searching. GAMBLER is equipped with an interface for convenience of annotation. All processes and options are manipulatable through a WWW browser that enables scientists to share their genome analysis results without choosing computer platforms.
Food & Nutrition Science Regular Papers
  • Hiroko KIKUCHI-HAYAKAWA, Harue SHIBAHARA-SONE, Kuniko OSADA, Norie ONO ...
    2000 年 64 巻 3 号 p. 466-475
    発行日: 2000年
    公開日: 2005/03/02
    ジャーナル フリー
      The effect of fermented skim milk (FSM) by Lactobacillus casei strain Shirota on plasma lipids in hamsters was examined. Hamsters fed on cholesterol-free and -enriched diets containing 30% FSM had lower levels of plasma triglyceride than those fed on the control diet. In the experiment with the cholesterol-enriched diet-fed hamsters, the plasma triglyceride level was suppressed by FSM at concentrations of 10% to 30%. Unfermented milk tended to lower the level of triglyceride, but not significantly. The plasma cholesterol concentration was not affected by an FSM and unfermented skim milk supplement to the diet. L. casei strain Shirota grew well in the presence of mixed lipid micelles containing bile acid, but did not have the ability to remove cholesterol from the culture broth. These results indicate that FSM lowered the plasma triglyceride level in hamsters.
  • Yoko NISHIKAWA, Tadao KURATA
    2000 年 64 巻 3 号 p. 476-483
    発行日: 2000年
    公開日: 2005/03/02
    ジャーナル フリー
      L-Ascorbic acid (AA) plays an important role in biological systems as an electron donor. Erythorbic acid (EA) is the epimer of AA and has chemical characteristics very similar to those of AA. It is demonstrated in the present study by 1H-NMR that dehydro-L-ascorbic acid (DAA) was reduced by EA under neutral conditions but not acidic, and that dehydroerythorbic acid (DEA) was also reduced by AA under the same conditions. These reactions also occurred at a low concentration close to the concentration of AA in such biological tissue as the liver. Furthermore, the interconversion of DAA and AA at neutral pH and low concentration was also confirmed by radioluminography. These results suggest the interconversion between DAA and AA in vivo.
  • Sejong OH, Randy W. WOROBO, Byoung-chul KIM, Sungsue RHEEM, Saehun KIM
    2000 年 64 巻 3 号 p. 516-522
    発行日: 2000年
    公開日: 2005/03/02
    ジャーナル フリー
      The cholera toxin (CT)-binding activity of purified κ-casein macropeptide (CMP) from bovine κ-casein was detected. In addition, a statistical model was developed to optimize the production of CMP. CMP was prepared by chymosin hydrolysis of κ-casein and a subsequent 3% trichloroacetic acid treatment. CMP was further fractionated in an ion-exchange column by FPLC. CT binding activity was eluted at 0.18 M NaCl and was a single 8.9 kDa peptide without tyrosine and arginine residues. The CT binding activity was rapidly lost by a carbohydrase treatment. The conditions for CMP production with chymosin were optimized by using the response surface methodology (RSM). The estimated optimum levels of the factors were as follows: reaction temperature, 38.5°C; pH, 6.44; and time, 35.9 min. A validation experiment was performed in which CMP was prepared under the predicted parameters, and it was ascertained that the estimated optimum conditions gave better production of CMP than any other conditions.
  • Hideyuki SONE, Michiko ITO, Muneshige SHIMIZU, Yuka SASAKI, Michio KOM ...
    2000 年 64 巻 3 号 p. 550-554
    発行日: 2000年
    公開日: 2005/03/02
    ジャーナル フリー
      Perifused isolated rat islets were used to show that biotin plus 16.5 mM glucose evoked more insulin secretion than 16.5 mM glucose alone. Whether or not this reinforcement of glucose-induced insulin secretion by biotin is unique was studied by using perifused islets stimulated with 16.5 mM glucose plus 100 μM of one of various components of the vitamin B group. No effect of any of these vitamins was found on glucose-induced insulin secretion. These results indicate that biotin is unique among the members of the vitamin B group in enhancing glucose-induced insulin secretion.
      Static incubation experiments showed that biotin did not potentiate insulin release when the islets were incubated with an experimental solution containing either no or 2.8 mM glucose. The addition of biotin to 27.7 mM glucose, which is the maximal concentration for stimulating insulin release, did not significantly enhance the effect of the glucose on insulin release (although it did at 16.5 mM glucose). These findings indicate that biotin, by itself, does not stimulate insulin secretion, and does not enhance glucose-induced insulin secretion beyond the ability of glucose itself to stimulate insulin secretion.
  • Guanghua WAN, Shoko OHNOMI, Norihisa KATO
    2000 年 64 巻 3 号 p. 555-561
    発行日: 2000年
    公開日: 2005/03/02
    ジャーナル フリー
      The effects were examined of the dietary level of fat on the activity of inducible nitric oxide synthase (iNOS) in the liver of rats. In experiment 1, rats were fed on a diet containing 5% or 20% beef tallow or safflower oil for 32 d. The animals were given a subcutaneous injection of the carcinogen, 1,2-dimethylhydrazine (DMH), on d 4. The activity of hepatic iNOS was significantly elevated by the high-fat diet, but was unaffected by the dietary source of the fat examined. In experiment 2, rats were fed on a 5% or 20% beef tallow diet for 11 d or 32 d with or without the DMH treatment. Feeding the high-fat diet and DMH treatment caused higher activity of hepatic iNOS. In experiment 3, the high-fat diet elevated hepatic iNOS activity and the amount of its protein in the lipopolysaccharide-treated rats. The results suggest that hepatic NO production is enhanced by a high-fat diet.
Food & Nutrition Science Notes
Microbiology & Fermentation Technology Regular Papers
  • Kuniho NAKATA, Naoko HARADA, Kunihito SUMITOMO, Kazuo YONEDA
    2000 年 64 巻 3 号 p. 459-465
    発行日: 2000年
    公開日: 2005/03/02
    ジャーナル フリー
      The antibiotic-producing bacterium, Pseudomonas fluorescens, is assumed to be important in protecting plants from soilborne diseases. S. fluorescens S272, a hyper-producing strain of pyoluteorin (PT) and 2,4-diacetylphloroglucinol (DG), had previously been isolated from soil. The present paper reported that the growth of water-cultivated Kaiware radish was promoted to 120-140% of its normal level by the coaddition of an S272 culture broth (0.01-1% v/v) and a polysaccharide flocculant (1-100 ppm) from Klebsiella pneumoniae H12. Tight adhesion of S272 cells to the root tissue was microscopically observed. The growth promotion is assumed to have been caused by antibiotic effects for the following two reasons: 1) PT (4 mg/l) and DG (24 mg/l) addition to a radish culture enhanced stem growth to 130% of the normal level; 2) a culture solution containing the S272 culture broth (0.01-1% v/v) markedly inhibited the decomposition of hypersensitive chrysanthemum leaves. A soil-cultivation experiment with Gomphrena globosa under natural conditions also exhibited enhanced stem length (160%) by coaddition of the S272 culture broth and H12 polysaccharide. These results suggest that polysaccharide-enhanced adhesion of P. fluorescens S272 cells might be useful for promoting plant growth through the increased antibiotic effect.
  • Shima EDA, Takayuki HOSHINO, Masanao ODA
    2000 年 64 巻 3 号 p. 484-491
    発行日: 2000年
    公開日: 2005/03/02
    ジャーナル フリー
      To identify the role of the downstream region of a hut promoter in regulation of the Bacillus subtilis hut operon, three single-base substitutions (+9G→A, +14C→T, and +23T→G) were introduced into the hut operon. Analysis of expression of the hut operon containing each of these three single-base substitutions and the hut-lacZ fusions with the single-base substitutions at position +14 showed that the position at +14 and probably the position at +23 were required for amino acid repression at the hut promoter, while the position at +14 was not required for catabolite repression at the hut promoter. The position at +9 was required for a histidine-dependent increase of activity of the hut promoter. Analysis of expression of the hut-lacZ fusions and the hut operon in the codY mutant indicated that the position at +14 and probably the position at +23 were involved in CodY-mediated amino acid repression at the hut promoter and that CodY was not required for catabolite repression at the hut promoter.
  • Masaharu ISHII, Seiichi TAKISHITA, Toshio IWASAKI, Yuwadee PEERAPORNPI ...
    2000 年 64 巻 3 号 p. 492-502
    発行日: 2000年
    公開日: 2005/03/02
    ジャーナル フリー
      A membrane-bound hydrogenase was purified to electrophoretic homogeneity from the cells of Hydrogenobacter thermophilus strain TK-6, an obligately autotrophic, thermophilic, hydrogen-oxidizing bacterium. Solubilization and purification were done aerobically in the presence of Triton X-100. Three chromatography steps were done for purification; Butyl-Sepharose, Mono-Q, and Superose 6, in this order. Purification was completed with 6.73% yield of total activity and with 21.4-fold increase of specific activity when compared with the values for the membrane fraction. The purified hydrogenase was shown to be a tetramer with α2β2 structure, with a molecular mass of 60,000 Da for the large subunit and 38,000 Da for the small subunit. The purified hydrogenase directly reduced methionaquinone with an apparent Km of around 300 μM and with a turnover number around 2900 (min-1). Metal analysis and EPR properties of the hydrogenase have shown that the enzyme is one of the [NiFe]-hydrogenases. Also, optimum pH and temperature for reaction, thermal stability, and electron acceptor specificity were reported. Finally, a model is presented for energy and central metabolism of H. thermophilus strain TK-6.
Microbiology & Fermentation Technology Notes
feedback
Top