Bioscience, Biotechnology, and Biochemistry
Online ISSN : 1347-6947
Print ISSN : 0916-8451
Volume 66 , Issue 10
Showing 1-45 articles out of 45 articles from the selected issue
Reviews
  • Hideaki NOJIRI, Toshio OMORI
    2002 Volume 66 Issue 10 Pages 2001-2016
    Published: 2002
    Released: June 19, 2003
    JOURNALS FREE ACCESS
      In the last decade, extensive investigation has been done on the bacterial degradation of dioxins and its related compounds, because this class of chemicals is highly toxic and has been widely distributed in the environment. These studies have revealed the primary importance of a novel dioxygenation reaction, called angular dioxygenation, in the aerobic bacterial degradation pathway of dioxin. Accompanied by the electron transport proteins, Rieske nonheme iron oxygenase catalyzes the incorporation of oxygen atoms to the ether bond-carrying carbon (the angular position) and an adjacent carbon, resulting in the irreversible cleavage of the recalcitrant aryl ether bond. The 2,2′,3-trihydroxybiphenyl or 2,2′,3-trihydroxydiphenyl ether derivatives formed are degraded through meta cleavage. In addition to the degradation system of dibenzofuran and dibenzo-p-dioxin (the nonchlorinated model compounds of dioxin), those of fluorene and carbazole were shown to function in dioxin degradation. Some dioxin degradation pathways have been studied biochemically and genetically. In addition, feasibility studies have shown that some dioxin-degrading strains can function in actual dioxin-contaminated soil. These studies provide useful information for the establishment of a bioremediation method for dioxin contamination. This review summarizes recent progress on molecular and biochemical bases of the bacterial aerobic degradation of dioxin and related compounds.
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  • Soichi ARAI, Yasushi MORINAGA, Toshikazu YOSHIKAWA, Eiichiro ICHIISHI, ...
    2002 Volume 66 Issue 10 Pages 2017-2029
    Published: 2002
    Released: June 19, 2003
    JOURNALS FREE ACCESS
      International recognition of functional foods has resulted in the recent global development of this field, which originated in Japan. The national policy on functional foods, in terms of “foods for specified health use”, also has been developing and has motivated the food industry to produce a variety of new food items. In Japan as well as in many other countries, academic and industrial scientists have been working in collaboration for the analysis and practical applications of functional food science. Emphasis has been placed on the study of antioxidant and anticarcinogenic food factors as well as pre- and probiotics. This review pinpoints recent trends in the science and industry in this field.
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Analytical Chemistry Note
  • Toshihide MICHIHATA, Toshihiro YANO, Toshiki ENOMOTO
    2002 Volume 66 Issue 10 Pages 2251-2255
    Published: 2002
    Released: June 19, 2003
    JOURNALS FREE ACCESS
      Volatile compounds from the headspace gas of ten brands of the Japanese fish sauce ishiru were analyzed by GC-MS with a thermal-desorption cold-trap system. Many volatile peaks were detected and 51 compounds were identified. The major volatile compounds in ishiru included aldehydes (such as 2-methylpropanal, 2-methylbutanal, 3-methylbutanal, and benzaldehyde), nitrogen-containing compounds (such as pyrazine derivatives and trimethylamine), sulfur-containing compounds (such as dimethyl disulfide), and ketones (such as 2-butanone and 3-methyl-2-butanone). On the other hand, volatile fatty acids were nearly absent in the headspace gas of ishiru.
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Organic Chemistry Regular Papers
  • Naoki ABE, Tadaharu ARAKAWA, Kazunobu YAMAMOTO, Akira HIROTA
    2002 Volume 66 Issue 10 Pages 2090-2099
    Published: 2002
    Released: June 19, 2003
    JOURNALS FREE ACCESS
      An incorporation study of [1-13C] and [1,2-13C2] labeled sodium acetates into sorbicillinol 1 established a ring closure system between C-1 and C-6 and the positions that were oxidized and/or methylated on a hexaketide chain. Subsequent investigations, using 13C-labeled 1 prepared from [1-13C] labeled sodium acetate, clearly demonstrated that both bisorbicillinol 2 and sorbicillin 6 incorporated 13C-labeled 1 into their carbon skeletons. 13C-labeled bisorbicillinols 2 derived from [1-13C]- and [2-13C]-labeled sodium acetates clearly indicate that these were on the biosynthetic route from 1 to bisorbibutenolide (bislongiquinolide) 3 and bisorbicillinolide 4 via 2 as a branching point in the fungus.
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  • Atsushi ISHIHARA, Yuki OGURA, Shin-ichi TEBAYASHI, Hajime IWAMURA
    2002 Volume 66 Issue 10 Pages 2176-2182
    Published: 2002
    Released: June 19, 2003
    JOURNALS FREE ACCESS
      The effects of jasmonic acid (JA) on secondary metabolism in barley (Hordeum vulgare L.) were investigated. A reversed-phase HPLC analysis revealed that the amount of a particular compound increased in excised barley leaf segments that had been treated with JA. This compound was purified and identified as 6´´´-feruloylsaponarin (1) by spectroscopic analyses and alkaline hydrolysis. A related compound, 6´´´-sinapoylsaponarin (2), was also found to accumulate in excised leaves independently of the JA treatment. The accumulation of these compounds was accompanied by a decrease in the saponarin (3) content. [8,9-13C]p-Coumaric acid and [2,3,4,5,6-2H]L-phenylalanine were effectively incorporated into the hydroxycinnamoyl moieties in 1 and 2, while the degree of incorporation of the labeled precursors into the saponarin part was small. These findings indicate that the hydroxycinnamoyl moieties of 1 and 2 are synthesized de novo from phenylalanine via the phenylpropanoid pathway, and that the saponarin part is mainly provided by the constitutive pool of 3.
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  • Somepalli VENKATESWARLU, Mudunuri S. S. RAJU, Gottumukkala V. SUBBARAJ ...
    2002 Volume 66 Issue 10 Pages 2236-2238
    Published: 2002
    Released: June 19, 2003
    JOURNALS FREE ACCESS
      Isoamoenylin (6), a dihydrostilbene from Dendrobium amoenum, was synthesised from 3,4,5-trimethoxybenzaldehyde (1) in four steps with an overall yield of 60%. The spectral data for synthetic 6 are in good agreement with those of the natural product. Isoamoenylin showed moderate antioxidative and weak antibacterial activities.
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Organic Chemistry Notes
Biochemistry & Molecular Biology Regular Papers
  • Seiji YAMADA, Kohei SURUGA, Masahiro OGAWA, Toshiyuki HAMA, Tadashi SA ...
    2002 Volume 66 Issue 10 Pages 2044-2051
    Published: 2002
    Released: June 19, 2003
    JOURNALS FREE ACCESS
      The appearance of NO2 reducing activity of cytochrome c (Cyt c) upon heat denaturation was investigated with equine heart Cyt c. Denatured equine heart Cyt c (dCyt c), which was treated at 100°C for 30 min, had NO2 reducing activity in the presence of dithionite and methylviologen in an aqueous solution under anaerobic conditions. In contrast, hemoglobin and myoglobin had no such activity under the same conditions. Using spectroscopic methods, we found that the appearance of this activity in the Cyt c was due to the following intramolecular changes: unfolding of the peptide chain, exposure of the heme, dissociation of the sixth ligand methionine sulfur, and appearance of autoxidizability. The dCyt c catalyzed NO2 reduction to NH4+ via ferrous-NO complexes, and this reaction was a 6-electron and 8-proton reduction. Sepharose-immobilized dCyt c had activity similar strength to that in solution. The resin retained the activity after five uses and even after storage for 1 year. On the basis of these results, we concluded that Cyt c acquired a new catalytic activity upon heat treatment, unlike to other familiar biological molecules.
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  • Kenji FUKUDA, Haruhide MORI, Masayuki OKUYAMA, Atsuo KIMURA, Hachiro O ...
    2002 Volume 66 Issue 10 Pages 2060-2067
    Published: 2002
    Released: June 19, 2003
    JOURNALS FREE ACCESS
      Partial amino acid sequences, the essential ionizable groups directly involved in catalytic reaction, and the subsite structure of β-D-glucosidase purified from a Streptomyces sp. were investigated in order to analyze the reaction mechanism. On the basis of the partial amino acid sequences, the enzyme seemed to belong to the family 1 of β-glucosidase in the classification of glycosyl hydrolases by Henrissat (1991). Dependence of the V and Km values on pH, when the substrate concentration was sufficiently lower than Km, gave the values of 4.1 and 7.2 for the ionization constants, pKe1 and pKe2 of essential ionizable groups 1 and 2 of the free enzyme, respectively. When the dielectric constant of the reaction mixture was decreased in the presence of 10% methanol, the pKe1 and pKe2, values shifted to higher, to +0.60 and +0.35 pH unit, respectively. The findings supported the notion that the essential ionizable groups of the enzyme were a carboxylate group (−COO, the group 1) and a carboxyl group (−COOH, the group 2). The subsite affinities Ai's in the active site were evaluated on the basis of the rate parameters of laminarioligosaccharides. Subsites 1 and 2 having positive Ai values (A1 was 1.10 kcal/mol and A2 was 4.98 kcal/mol) were considered to probably facilitate the binding of the substrate to the active site. However, the subsites 3 and 4 showed negative Ai values (A3 was −0.21 kcal/mol and A4 was −2.8 kcal/mol).
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  • Mohammad Zakir HOSSAIN, Masayuki FUJITA
    2002 Volume 66 Issue 10 Pages 2068-2076
    Published: 2002
    Released: June 19, 2003
    JOURNALS FREE ACCESS
      A major species of glutathione S-transferase (GST), Pugf, was highly purified from pumpkin flowers. Two-dimensional electrophoresis of the purified enzyme gave two adjacent protein spots. The specific activity of the purified enzyme was 2.4 μmol min−1 mg−1 protein for 1-chloro-2,4-dinitrobenzene. This value is one to two orders of magnitude lower than that of pumpkin tau-type GSTs.
    The expression pattern of Pugf in healthy pumpkin plants and responses to various stresses were examined by western blotting. Pugf was found in high concentrations in petioles, stems, and roots as well as flowers, and was more abundant in expanding young organs than in fully expanded mature organs. Dehydration caused a slight increase in its concentration, but high and low temperatures, salty stress, and 2,4-dichlorophenoxyacetic acid seemed to have no effects.
    A cDNA encoding Pugf was cloned and sequenced. Sequence comparison with other plant GSTs suggested that it should be classified as a phi-type GST.
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  • Naoto IIJIMA, Hiroto YOSHINO, Lim Chee TEN, Akikazu ANDO, Katsunori WA ...
    2002 Volume 66 Issue 10 Pages 2083-2089
    Published: 2002
    Released: June 19, 2003
    JOURNALS FREE ACCESS
      Our previous studies on the fruit body lectin of Pleurotus cornucopiae revealed the existence of three isolectins, composed of two homodimers and one heterodimer of 16- and 15-kDa subunits. In this study, two genes encoding the lectins were cloned and characterized. Both genes encoded 144 amino acids and only 5 amino acids were different within the coding region, but the nucleotide sequences of the 5′-upstream and 3′-downstream regions differed extensively. Southern hybridization with gene-specific probes showed that one gene encoded the 16-kDa and the other encoded the 15-kDa subunit. Functional lectins were synthesized in Escherichia coli under the direction of these genes. On SDS-PAGE, the recombinant lectins showed the same banding patterns as the native lectins. In amino acid sequence, these lectins showed extensive similarity with the lectin from a nematode-trapping ascomycete fungus, Arthrobotrys oligospora, suggesting that the lectins might also function in capturing nematodes.
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  • Atsushi TAKABAYASHI, Tsuyoshi ENDO, Toshiharu SHIKANAI, Fumihiko SATO
    2002 Volume 66 Issue 10 Pages 2107-2111
    Published: 2002
    Released: June 19, 2003
    JOURNALS FREE ACCESS
      We reported previously that an ndhB gene disruptant, ΔndhB, had the same phenotype as wild-type tobacco plants under normal growth conditions. Two other groups have reported conflicting phenotypes with each other for ndhCKJ operon disruptants. Here, we generated two transformants in which the ndhCKJ operon was disrupted, and found that new transformants had the same phenotype as ΔndhB. After illumination with visible light, all ndh disruptants had higher levels of steady-state fluorescence than wild-type controls when measured under weak light, suggesting that reduction of the plastoquinone pool in ndh disruptants was greater than that in wild-type controls. The weak light itself could not reduce the plastoquinone much, so the reduction in the plastoquinone in the mutant was due to electron donation from stromal reductants generated during illumination with the strong light. These results supported the hypothesis that NAD(P)H dehydrogenase prevents overreduction in chloroplasts and suggested that chlororespiratory oxidase did not function under low light or in the dark.
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  • Toshihide OKAJIMA, Daisuke KITAGUCHI, Kumiko FUJII, Hidetada MATSUOKA, ...
    2002 Volume 66 Issue 10 Pages 2112-2124
    Published: 2002
    Released: June 19, 2003
    JOURNALS FREE ACCESS
      A gene coding for adenylate kinase was cloned from an extremely thermoacidophilic archaeon Sulfolobus solfataricus. The open reading frame of the sequenced gene consisted of 585 nucleotides coding for a polypeptide of 195 amino acid residues with a calculated molecular weight of 21,325. Although the S. solfataricus adenylate kinase, which belonged to the small variants of the adenylate kinase family, had low sequence identities with bacterial and eukaryotic enzymes, a functionally important glycine-rich region and also two invariant arginine residues were conserved in the sequence of the S. solfataricus enzyme. The recombinant enzyme, overexpressed in Escherichia coli and purified to homogeneity, had high affinity for AMP and high thermal stability, comparable to the extremely thermostable enzyme from a similar archaeon, S. acidocaldarius. Furthermore, gel filtration and sedimentation analyses showed that the S. solfataricus adenylate kinase was a homotrimer in solution, which is a novel subunit structure for nucleoside monophosphate kinases.
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  • Takeshi SAITO, Norio TANAKA, Takao SHINOZAWA
    2002 Volume 66 Issue 10 Pages 2125-2133
    Published: 2002
    Released: June 19, 2003
    JOURNALS FREE ACCESS
      For 16 commercial cultivars of Lentinula edodes, DNA fragments for the nuclear rDNA intergenic spacers IGS1 and IGS2 were amplified and analyzed. IGS1 contained a subrepeat region, named SR1, and IGS2 contained a pair of direct repeats and a subrepeat region, named SR2. Three and five types of subrepeats were found in SR1 and SR2, respectively. Heterogeneity in the lengths of IGS1 and IGS2 arose mainly from the number of different kinds of subrepeats within SR1 and SR2. The DNA fingerprints from the PCR products targeting SR1 and SR2 were specific for each of the 16 cultivars, and had enough variation for discrimination among the cultivars. This result suggests that the DNA fingerprints targeting SR1 and SR2 are useful for investigations of L. edodes cultivars.
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  • Takao KAWAI, Yasuhiko SUZUKI, Souji EDA, Tetsuo KASE, Katsuki OHTANI, ...
    2002 Volume 66 Issue 10 Pages 2134-2145
    Published: 2002
    Released: June 19, 2003
    JOURNALS FREE ACCESS
      Collectins are members of the superfamily of vertebrate C-type lectins that contain a collagen-like region, and are involved in first-line host defense. We earlier cloned and characterized a new kind of collectin, collectin liver 1 (CL-L1). In this study, we isolated the mouse homologue of CL-L1 encoding 277 amino acid residues; its deduced protein sequence was 88% identical with human CL-L1. Mouse CL-L1 mRNA was expressed mainly in the liver and stomach, but was found also in muscles, testes, intestines, and embryos. In mouse embryos, the level of CL-L1 mRNA gradually increased with embryonic age. In 16-day-old mouse embryos, CL-L1 mRNA was expressed in the liver, amnion, and visceral yolk sac. The mouse CL-L1 gene, Cll1 was found on chromosome 15 in a region syntenic with human chromosome 8q. CL-L1 was a highly conserved protein in mammals, birds, and fish.
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  • Sorgan S. K. TAI, Miles C. M. CHEN, Chi-Chung PENG, Jason T. C. TZEN
    2002 Volume 66 Issue 10 Pages 2146-2153
    Published: 2002
    Released: June 19, 2003
    JOURNALS FREE ACCESS
      Oleosins are structural proteins sheltering the oil bodies of plant seeds. Two isoform classes termed H- and L-oleosin are present in diverse angiosperms. Two H-oleosins and one L-oleosin were identified in sesame oil bodies from the protein sequences deduced from their corresponding cDNA clones. Sequence analysis showed that the main difference between the H- and L-isoforms is an insertion of 18 residues in the C-terminal domain of H-oleosins. H-oleosin, presumably derived from L-oleosin, was duplicated independently in several species. All known oleosins can be classified as one of these two isoforms. Single copy or a low copy number was detected by Southern hybridization for each of the three oleosin genes in the sesame genome. Northern hybridization showed that the three oleosin genes were transcribed in maturing seeds where oil bodies are being assembled. Artificial oil bodies were reconstituted with triacylglycerol, phospholipid, and sesame oleosin isoforms. The results indicated that reconstituted oil bodies could be stabilized by both isoforms, but L-oleosin gave slightly more structural stability than H-oleosin.
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  • Kiyoshi SATOUCHI, Yoshifumi KODAMA, Kaoru MURAKAMI, Tamotsu TANAKA, Hi ...
    2002 Volume 66 Issue 10 Pages 2154-2160
    Published: 2002
    Released: June 19, 2003
    JOURNALS FREE ACCESS
      A lipase-inhibiting protein was isolated from lipoxygenase (LOX)-deficient soybean seeds. The molecular mass of the protein was 56.0-kDa and the N-terminal amino acid was blocked. The protein was identified by peptide mass fingerprinting in combination with matrix-assisted laser desorption ionization/time-of-flight mass spectrometry. The masses of the lysyl endopeptidase-digested peptides of the 56.0-kDa inhibiting protein were almost identical to the calculated masses of the theoretically predicted lysyl endopeptidase-treated peptides of β-amylase from soybean seed. In a previous paper (Biosci. Biotechnol. Biochem., 62, 1498-1503, 1998), we reported that LOX-1, an isozyme of soybean seed LOX, inhibited hydrolysis of soybean oil by pancreatic lipase. Purified β-amylase also inhibited lipase activity, although the magnitude of inhibition was weaker than that by LOX-1. Thus, there are at least two lipase-inhibiting proteins, one is a LOX and the other is a β-amylase, in soybean seed.
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  • Ryoko AKIYAMA, Yoshihiro SATO, Susumu KAJIWARA, Kazuo SHISHIDO
    2002 Volume 66 Issue 10 Pages 2183-2188
    Published: 2002
    Released: June 19, 2003
    JOURNALS FREE ACCESS
      Three cytochrome P450 genes, named Le. cyp1, Le. cyp2, and Le. cyp3, were isolated from the basidiomycete Lentinula edodes. Le. cyp1 and Le. cyp2 contained coding regions of 1500 bp and 1497 bp, respectively, but Le. cyp3 was found to be a defective gene. The deduced amino acid sequences of Le. CYP1 (CYP510A1, 500 amino acids) and Le. CYP2 (CYP510A3, 499 amino acids) were highly similar to each other (87% identical) and they had 32-33% identities to that of Coprinus cinereus P450 (CYP502) and 27-28% identities to those of two Aspergillus P450s (CYP64 family). Quantitative RT-PCR analysis of the transcripts of Le. cyp1 and Le. cyp2 genes in the course of fruiting-body development of L. edodes showed that the primordium seems to contain larger amounts of these transcripts. The transcript levels of both of these genes in the stipe of the premature fruiting body were higher than those in the whole pileus and gill tissue.
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  • Kieko SAITO, Hisashi YOSHIOKA
    2002 Volume 66 Issue 10 Pages 2189-2193
    Published: 2002
    Released: June 19, 2003
    JOURNALS FREE ACCESS
      We previously found that one of the pharmacological effects of N-tert-butyl-α-phenylnitrone (PBN) is the release of nitric oxide (NO) under oxidative conditions. However, to confirm this hypothesis in vivo, NO released from PBN must be distinguished from NO produced in biological systems, and therefore we undertook the synthesis of PBN using labeled 15N to identify its corresponding 15NO in vivo. The properties were examined with an ESR spectrometer. To synthesize 15N-PBN, the starting material, ammonium-15N chloride, was converted to 2-amino-15N-2-methylpropane, oxidized to 2-methyl-2-nitropropane-15N, and finally reacted with benzaldehyde to give 15N-PBN. The final product was purified by repeated sublimation. With ferrous sulfate-methyl glucamine dithiocarbamate complex, Fe (MGD)2, as a trapping agent to measure the NO levels of 15N-PBN or 14N-PBN in vitro, the peak intensity of 15NO[Fe(MGD)2] was over 50% stronger than that of 14NO[Fe(MGD)2], and that 15NO and 14NO had the corresponding two-and three line hyperfine structures due to their nuclear spin quantum numbers. Subsequently, the ESR spectrum of 15NO derived from 15N-PBN was significantly different than that of lipopolysaccharide (LPS)-induced NO, which was derived from biological cells, and therefore we have demonstrated the possibility to distinguish 15NO from PBN and 14NO generated from cells. These results suggested that 15N-PBN is a useful molecule, not only as a spin-trapping agent, but also as an NO donor to explore the pharmacological mechanisms of PBN in vivo.
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  • Masao KITABAYASHI, Yoshiaki NISHIYA, Muneharu ESAKA, Mitsuo ITAKURA, T ...
    2002 Volume 66 Issue 10 Pages 2194-2200
    Published: 2002
    Released: June 19, 2003
    JOURNALS FREE ACCESS
      The gene encoding the proliferating cell nuclear antigen (PCNA), a sliding clamp of DNA polymerases, was cloned from an euryarchaeote, Thermococcus kodakaraensis KOD1. The PCNA homologue, designated Tk-PCNA, contained 249 amino acid residues with a calculated molecular mass of 28,200 Da and was 84.3% identical to that from Pyrococcus furiosus. Tk-PCNA was overexpressed in Escherichia coli and purified. This protein stimulated the primer extension abilities of the DNA polymerase from T. kodakaraensis KOD1 ‘KOD DNA polymerase’. The stimulatory effect of Tk-PCNA was observed when a circular DNA template was used and was equally effective on both circular and linear DNA. The Tk-PCNA improved the sensitivity of PCR without adverse effects on fidelity with the KOD DNA polymerase. This is the first report in which a replication-related factor worked on PCR.
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Biochemistry & Molecular Biology Notes
Biochemistry & Molecular Biology Preliminary Communication
  • Kiyoshi SUGAWARA, Naoshi DOHMAE, Koji KASAI, Hisako SAIDO-SAKANAKA, Su ...
    2002 Volume 66 Issue 10 Pages 2292-2296
    Published: 2002
    Released: June 19, 2003
    JOURNALS FREE ACCESS
      An important role of protein ADP-ribosylation in bacterial morphogenesis has been proposed (J. Bacteriol. 178, 3785-3790; 178, 4935-4941). To clarify the detail of ADP-ribosylation, we identified a new kind of target protein for ADP-ribosylation in Streptomyces coelicolor A3(2) grown to the late growth phase. All four proteins (MalE, BldKB, a periplasmic protein for binding branched-chain amino-acids, and a periplasmic solute binding protein) were functionally similar and participated in the regulation of transport of metabolites or nutrients through the membrane. ADP-ribosylation was likely to occur on a cysteine residue, because the modification group was removed by mercuric chloride treatment. The modification site may be the site of lipoprotein modification necessary for protein export. This report is the first suggesting that certain proteins involved in membrane transport can be ADP-ribosylated.
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Food & Nutrition Science Regular Papers
  • Soo Bong CHOI, Sunmin PARK
    2002 Volume 66 Issue 10 Pages 2036-2043
    Published: 2002
    Released: June 19, 2003
    JOURNALS FREE ACCESS
      The aim of this study was to investigate the effects of three steroidal glycosides (SG-100, SG-280, and SG-460) obtained from Polygonatum odoratum (Mill.) Druce. on insulin secretion, insulin action, and relative glucose uptake in various tissues of 90% pancreatectomized male Sprague-Dawley rats. One of the compounds (30 mg/kg body weight daily) with a 40%-fat diet was orally administered to a group of such rats for 13 weeks. On the day after a hyperglycemic clamp, euglycemic hyperinsulinemic clamp with 1 μCi of [1-14C]2-deoxyglucose per 100 g body weight was used. Serum glucose levels were lowest in the rats receiving SG-100. Insulin secretion from pancreatic β-cells did not change with SG administration. Whole-body glucose disposal rates increased with SG-100 administration by 39%. SG-100 increased the glycogen contents and glycogen synthase activity in the soleus muscle of pancreatectomized rats. Uptake of [1-14C]2-deoxyglucose into the soleus muscle was higher in such rats receiving SG-100 than in rats receiving other compounds. In conclusion, SG-100 has an antihyperglycemic effect by promoting peripheral insulin sensitivity without changing insulin secretion.
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  • Miwa KUROYANAGI, Eriko SHIMAMURA, Mihyan KIM, Nobuhiko ARAKAWA, Yoko F ...
    2002 Volume 66 Issue 10 Pages 2077-2082
    Published: 2002
    Released: June 19, 2003
    JOURNALS FREE ACCESS
      To clarify the role of L-ascorbic acid (AsA) in the formation of pyridinoline, we examined the effects of AsA in vitro using soluble collagen and partially purified lysyl oxidase from bovine aorta. The concentration of dehydrodihydroxylysinonorleucine decreased when AsA was added in the early stage of pyridinoline formation. However, when AsA was added in a later stage of pyridinoline formation, the concentration of pyridinoline was not affected. These findings indicated that AsA was involved in the initial enzymatic reaction in pyridinoline synthesis. We purified lysyl oxidase to confirm its association of AsA. AsA inhibited the enzyme activity. Erythorbic acid and 3,4-dihydroxybenzoate suppressed the enzyme activity as well as AsA did. The inhibition by AsA of the lysyl oxidase activity arose from characteristics of AsA structure. AsA might be important in the regulation of the oxidative reaction of lysine.
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Food & Nutrition Science Notes
  • Tomoaki NISHIKAWA, Norihiko YAMADA, Atsuhiko HATTORI, Hiroyuki FUKUDA, ...
    2002 Volume 66 Issue 10 Pages 2221-2223
    Published: 2002
    Released: June 19, 2003
    JOURNALS FREE ACCESS
      Ajoene, a major compound containing sulfur in oil-macerated garlic products, inhibited in a two-stage carcinogenesis test on mouse skin. Treatment with ajoene suppressed skin tumor formation, depending on the amount. In particular, the group treated with 250 μg of ajoene had only 4.9% the number of tumors per mouse compared with the control group at 18 weeks.
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  • Tatsuya SUGAWARA, Mikio KINOSHITA, Masao OHNISHI, Teruo MIYAZAWA
    2002 Volume 66 Issue 10 Pages 2228-2231
    Published: 2002
    Released: June 19, 2003
    JOURNALS FREE ACCESS
      The apoptotic effects of plant sphingoid bases prepared from wheat-flour cerebroside on human colorectal cancer DLD-1 cells were examined. The viability of DLD-1 cells treated with such plant sphingoid bases was reduced in a dose-dependent manner and was similar to that of cells treated with sphingosine. Morphological changes such as condensed chromatin fragments were found, so those sphingoid bases reduced cell viability through causing apoptosis in these cells.
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  • Kimio SUGIYAMA, Yasuhiko SHIMADA, Kasumi IWAI, Tatsuya MORITA
    2002 Volume 66 Issue 10 Pages 2232-2235
    Published: 2002
    Released: June 19, 2003
    JOURNALS FREE ACCESS
      Effects of dietary protein type on lipopolysaccharide (LPS)-induced hepatitis, as assessed by plasma alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activities, were investigated in D-galactosamine (GalN)-sensitized rats. The plasma ALT and AST activities in rats fed on 25% soybean protein isolate (SPI) diet were significantly suppressed to about 1/4 and 1/5 of the values in rats fed on 25% casein diet, respectively, 8 h after the injection of LPS+GalN. Although hepatic ALT and AST activities of normal rats were also lower in the SPI group than in the casein group, this could not explain the differences in plasma enzyme activities between the two groups. The hepatic glutathione concentration of normal rats was lower in the SPI group than in the casein group, but it was reversed in rats injected with drugs. The results suggest that SPI can protect animals from LPS+GalN-induced hepatitis, and that the hepatic glutathione level may participate in the effects of SPI.
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  • Kiyoshi TAJIMA, Osamu ENISHI, Masahiro AMARI, Makoto MITSUMORI, Hirosh ...
    2002 Volume 66 Issue 10 Pages 2247-2250
    Published: 2002
    Released: June 19, 2003
    JOURNALS FREE ACCESS
      PCR primers for the detection of materials derived from ruminants, pigs, and chickens were newly designed on the basis of sequences of the Art2 short interspersed repetitive element (SINE), PRE-1 SINE, and CR1 long interspersed repetitive element (LINE), respectively. These primers amplified the SINE or LINE from total DNA extracted from the target animals and from test feed containing commercial meat and bone meal (MBM). With the primers, detection of Art2, PRE-1, or CR1 in test feed at concentrations of 0.01% MBM or less was possible. This method was suitable for the detection of microcontamination of feed by animal materials.
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Microbiology & Fermentation Technology Regular Papers
  • Takao INOUE, Kazuo KAMIMURA, Tsuyoshi SUGIO
    2002 Volume 66 Issue 10 Pages 2030-2035
    Published: 2002
    Released: June 19, 2003
    JOURNALS FREE ACCESS
      Strain OKM-9 is a mesophilic, mixotrophic iron-oxidizing bacterium that absolutely requires ferrous iron as its energy source and L-amino acids (including L-glutamate) as carbon sources for growth. The properties of the L-glutamate transport system were studied with OKM-9 resting cells, plasma membranes, and actively reconstituted proteoliposomes. L-Glutamate uptake into resting cells was totally dependent on ferrous iron that was added to the reaction mixture. Potassium cyanide, an iron oxidase inhibitor, completely inhibited the activity at 1 mM. The optimum pH for Fe2+-dependent uptake activity of L-glutamate was 3.5-4.0. Uptake activity was dependent on the concentration of the L-glutamate. The Km and Vmax for L-glutamate were 0.4 mM and 11.3 nmol•min−1•mg−1, respectively. L-Aspartate, D-aspartate, D-glutamate, and L-cysteine strongly inhibited L-glutamate uptake. L-Aspartate competitively inhibited the activity, and the apparent Ki for this amino acid was 75.9 μM. 2,4-Dinitrophenol, carbonyl cyanide m-chlorophenylhydrazone, gramicidin D, valinomycin, and monensin did not inhibit Fe2+-dependent L-glutamate uptake. The OKM-9 plasma membranes had approximately 40% of the iron-oxidizing activity of the resting cells and approximately 85% of the Fe2+-dependent uptake activity. The glutamate transport system was solubilized from the membranes with 1% n-octyl-β-D-glucopyranoside and reconstituted into a lecithin liposome. The L-glutamate transport activity of the reconstituted proteoliposomes was 8-fold than that of the resting cells. The Fe2+-dependent L-glutamate uptake observed here seems to explain the mixotrophic nature of this strain, which absolutely requires Fe2+ oxidation when using amino acids as carbon sources.
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  • Fumihiko YAMAGUCHI, Shinji KOGA, Issei YOSHIOKA, Mamoru TAKAHASHI, Har ...
    2002 Volume 66 Issue 10 Pages 2052-2059
    Published: 2002
    Released: June 19, 2003
    JOURNALS FREE ACCESS
      Bacillus stearothermophilus H-804 isolated from a hot spring in Beppu, Japan, produced an ammonia-specific NAD synthetase (EC 6.3.1.5). The enzyme specifically used NH3 as an amide donor for the synthesis of NAD as it formed AMP and pyrophosphate from deamide-NAD and ATP. None of the l-amino acids tested, such as l-asparagine or l-glutamine, or other amino compounds such as urea, uric acid, or creatinine was used instead of NH3. Mg2+ was needed for the activity, and the maximum enzyme activity was obtained with 3 mM MgCl2. The molecular mass of the native enzyme was 50 kDa by gel filtration, and SDS-PAGE showed a single protein band at the molecular mass of 25 kDa. The optimum pH and temperature for the activity were from 9.0 to 10.0 and 60°C, respectively. The enzyme was stable at a pH range of 7.5 to 9.0 and up to 60°C. The Km for NH3, ATP, and deamide-NAD were 0.91, 0.052, and 0.028 mM, respectively. The gene encoding the enzyme consisted of an open reading frame of 738 bp and encoded a protein of 246 amino acid residues. The deduced amino acid sequence of the gene had about 32% homology to those of Escherichia coli and Bacillus subtilis NAD synthetases. We caused the NAD synthetase gene to be expressed in E. coli at a high level; the enzyme activity (per liter of medium) produced by the recombinant E. coli was 180-fold that of B. stearothermophilus H-804. The specific assay of ammonia and ATP (up to 25 μM) with this stable NAD synthetase was possible.
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  • Shin-ichi YAMAZAKI, Tsutomu KANEKO, Naoki TAKETOMO, Kenji KANO, Tokuji ...
    2002 Volume 66 Issue 10 Pages 2100-2106
    Published: 2002
    Released: June 19, 2003
    JOURNALS FREE ACCESS
      It can be expected that extracellular electron transfer to regenerate NAD+ changes the glucose metabolism of the homofermentative lactic acid bacteria. In this work, the glucose metabolism of Lactobacillus plantarum and Lactococcus lactis was examined in resting cells with 2-amino-3-carboxy-1,4-naphthoquinone (ACNQ) as the electron transfer mediator and ferricyanide (Fe(CN)63−) as the extracellular electron acceptor. NADH in the cells was oxidized by ACNQ with the aid of diaphorase, and the reduced ACNQ was reoxidized with Fe(CN)63−. The extracellular electron transfer system promoted the generation of pyruvate, acetate, and acetoin from glucose, and restricted lactate production. Diaphorase activity increased when cultivation was aerobic, and this increased the concentrations of pyruvate, acetate, and acetoin relative to the concentration of lactate to increase in the presence of ACNQ and Fe(CN)63−.
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  • Hiroyuki WAKABAYASHI, Susumu TERAGUCHI, Yoshitaka TAMURA
    2002 Volume 66 Issue 10 Pages 2161-2167
    Published: 2002
    Released: June 19, 2003
    JOURNALS FREE ACCESS
      This study aimed to find antibiotics or other compounds that could increase the antimicrobial activity of an antimicrobial peptide, lactoferricin B (LFcin B), against Staphylococcus aureus, including antibiotic-resistant strains. Among conventional antibiotics, minocycline increased the bactericidal activity of LFcin B against S. aureus, but methicillin, ceftizoxime, and sulfamethoxazole-trimethoprim did not have such an effect. The combination of minocycline and LFcin B had synergistic effects against three antibiotic-resistant strains of S. aureus, according to result of checkerboard analysis. Screening of 33 compounds, including acids and salts, alcohols, amino acids, proteins and peptides, sugar, and lipids, showed that medium-chain monoacylglycerols increased the bactericidal activity of LFcin B against three S. aureus strains. The short-term killing test in water and the killing curve test in growing cultures showed that a combination of LFcin B and monolaurin (a monoacylglycerol with a 12-carbon acyl chain) killed S. aureus more rapidly than either agent alone. These findings may be helpful in the application of antimicrobial peptides in medical or other situations.
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  • Sunhwa KIM, Ichiro MATSUO, Katsumi AJISAKA, Harushi NAKAJIMA, Katsuhik ...
    2002 Volume 66 Issue 10 Pages 2168-2175
    Published: 2002
    Released: June 19, 2003
    JOURNALS FREE ACCESS
      We isolated a β-N-acetylglucosaminidase encoding gene and its cDNA from the filamentous fungus Aspergillus nidulans, and designated it nagA. The nagA gene contained no intron and encoded a polypeptide of 603 amino acids with a putative 19-amino acid signal sequence. The deduced amino acid sequence was very similar to the sequence of Candida albicans Hex1 and Trichoderma harzianum Nag1. Yeast cells containing the nagA cDNA under the control of the GAL1 promoter expressed β-N-acetylglucosaminidase activity. The chromosomal nagA gene of A. nidulans was disrupted by replacement with the argB marker gene. The disruptant strains expressed low levels of β-N-acetylglucosaminidase activity and showed poor growth on a medium containing chitobiose as a carbon source. Aspergillus oryzae strain carrying the nagA gene under the control of the improved glaA promoter produced large amounts of β-N-acetylglucosaminidase in a wheat bran solid culture.
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  • Takanori TSUKAMOTO, Hitoshi MURATA, Akira SHIRATA
    2002 Volume 66 Issue 10 Pages 2201-2208
    Published: 2002
    Released: June 19, 2003
    JOURNALS FREE ACCESS
      Bacterial isolates from wild Agaricales fungi detoxified tolaasin, the inducer of brown blotch disease of cultivated mushrooms produced by Pseudomonas tolaasii. Mycetocola tolaasinivorans and Mycetocola lacteus were associated with fruit bodies of wild Pleurotus ostreatus and wild Lepista nuda, respectively. Tolaasin-detoxifying bacteria belonging to other genera were found in various wild mushrooms. An Acinetobacter sp. was isolated from fruit bodies of Tricholoma matsutake, Bacillus pumilus was isolated from Coprinus disseminatus, and Sphingobacterium multivorum was isolated from Clitocybe clavipes. A Pedobacter sp., which seemed not be identifiable as any known bacterial species, was isolated from a Clitocybe sp. Tolaasin-detoxifying bacteria identified thus far were attached to the surface of mycelia rather than residing within the fungal cells. M. tolaasinivorans, M. lacteus, B. pumilus, the Pedobacter sp., and S. multivorum efficiently detoxified tolaasin and strongly suppressed brown blotch development in cultivated P. ostreatus and Agaricus bisporus in vitro, but the Acinetobacter sp. did so less efficiently. These bacteria may be useful for the elucidation of mechanisms involved in tolaasin-detoxification, and may become biological control agents of mushroom disease.
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  • Noriyuki OCHIAI, Makoto FUJIMURA, Michiyo OSHIMA, Takayuki MOTOYAMA, A ...
    2002 Volume 66 Issue 10 Pages 2209-2215
    Published: 2002
    Released: June 19, 2003
    JOURNALS FREE ACCESS
      We investigated the effects of iprodione and fludioxonil on the pathogenic yeast Candida albicans. Growth of the wild-type IFO1385 strain of C. albicans was inhibited by both fungicides, while Saccharomyces cerevisiae was basically unaffected by them even at a concentration of 25 μg/ml. Both fungicides stimulated glycerol synthesis in C. albicans but not in S. cerevisiae. The antioxidant α-tocopherol acetate and the cytochrome P-450 inhibitor piperonyl butoxide antagonized the fungitoxicity of iprodione and fludioxonil in C. albicans. It is known that mutations within the histidine kinase NIK1/OS-1 gene confer resistance to iprodione and fludioxonil in Neurospora crassa, while the fungicide-insensitive S. cerevisiae has only one histidine kinase SLN1 gene in its genome. In contrast, C. albicans has three histidine kinase genes, namely CaSLN1, CaNIK1/COS1, and CaHK1, the null mutants of which were found to impair the hyphal formation. Iprodione and fludioxonil were found to suppress filamentation when the IFO1385 strain was incubated on a solid medium containing fetal bovine serum. These observations suggest that iprodione and fludioxonil interfere with the CaNIK1/COS1 signal transduction pathway, resulting in glycerol synthesis stimulation and the inhibition of hyphal formation.
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  • Naoko KAGA, Genryou UMITSUKI, Kazuo NAGAI, Masaaki WACHI
    2002 Volume 66 Issue 10 Pages 2216-2220
    Published: 2002
    Released: June 19, 2003
    JOURNALS FREE ACCESS
      Escherichia coli RNase G, encoded by the rng gene, is involved in the processing of 16S rRNA and degradation of the adhE mRNA encoding a fermentative alcohol dehydrogenase. In a search for the intracellular target RNAs of RNase G other than the 16S rRNA precursor and adhE mRNA, total cellular proteins from rng+ and rng::cat cells were compared by two-dimensional gel electrophoresis. The amount of enolase encoded by the eno gene reproducibly increased two- to three-fold in the rng::cat mutant strain compared with the rng+ parent strain. Rifampicin chase experiments showed that the half-life of the eno mRNA was some 3 times longer in the rng::cat mutant than in the wild type. These results indicate that the eno mRNA was a substrate of RNase G in vivo, in addition to 16S rRNA precursor and adhE mRNA.
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Microbiology & Fermentation Technology Notes
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