Bioscience, Biotechnology, and Biochemistry
Online ISSN : 1347-6947
Print ISSN : 0916-8451
Volume 67 , Issue 1
Showing 1-38 articles out of 38 articles from the selected issue
Organic Chemistry Preliminary Communication
Biochemistry & Molecular Biology Regular Papers
  • Rie KAWAI, Makoto YOSHIDA, Tomomi TANI, Kiyohiko IGARASHI, Tsuyoshi OH ...
    2003 Volume 67 Issue 1 Pages 1-7
    Published: 2003
    Released: June 25, 2003
    JOURNALS FREE ACCESS
      The extracellular β-glucosidase from the white-rot fungus Phanerochaete chrysosporium was expressed heterologously in the methylotrophic yeast Pichia pastoris. After 7 days' cultivation in an induction medium containing 1% (v/v) methanol, the expression level of the recombinant enzyme was 28,500 U/l, 38 times that of the wild-type enzyme. The specific activity of the crude recombinant enzyme for p-nitrophenyl-β-D-glucoside was 52 U/mg, 37 times that of the wild-type enzyme; this difference made the purification of the enzyme simple. On a SDS-PAGE, the molecular mass of the recombinant enzyme was 133 kDa, and that of the wild-type enzyme was 116 kDa, but the difference had no effect on the hydrolysis of cellobiose or p-nitrophenyl-β-D-glucoside. We concluded that the recombinant enzyme produced by Pichia pastoris retains the catalytic properties of the wild-type enzyme from Phanerochaete chrysosporium.
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  • Isao KOBAYASHI, Masahiro TOKUDA, Hiroyuki HASHIMOTO, Takashi KONDA, Hi ...
    2003 Volume 67 Issue 1 Pages 29-35
    Published: 2003
    Released: June 25, 2003
    JOURNALS FREE ACCESS
      A fungus producing an α-glucosidase that synthesizes α-1,3- and α-1,2-linked glucooligosaccharides by transglucosylation was isolated and identified as Paecilomyces lilacinus. The cell-bound enzyme responsible for the synthesis was extracted by suspension of mycelia with 0.1 M phosphate buffer (pH 8.0), and the extract was purified. The molecular weight and the isoelectric point were estimated to be 54,000 and 9.1, respectively. The enzyme was most active at pH 5.0 and 65°C. The enzyme hydrolyzed maltose, nigerose, and kojibiose. The enzyme also hydrolyzed soluble starch and amylose with the rate toward maltose. p-Nitrophenyl α-glucoside and isomaltose were not good substrates. The enzyme had high transglucosylation activity to synthesize oligosaccharides containing α-1,3- and α-1,2-linkages. At an early stage of the reaction, considerable maltotriose, 4-O-α-nigerosyl-D-glucose, and 4-O-α-kojibiosyl-D-glucose were synthesized. Afterwards, nigerose and kojibiose were accumulated gradually with glucose as an acceptor.
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  • Akihiro NAKAMURA, Hirokazu MAEDA, Misae MIZUNO, Yoko KOSHI, Yasunori N ...
    2003 Volume 67 Issue 1 Pages 68-76
    Published: 2003
    Released: June 25, 2003
    JOURNALS FREE ACCESS
      The fruit extracts of ripening cv. Japanese Persimmon, “Saijyo”, contained a number of glycosidases and glycanases. Among them, β-galactosidase appeared to be the most significant, and the activity increased in parallel with tissue ripening. Persimmon β-galactosidase was presented in at least three isoforms, β-galactosidase-I (pI=4.88), β-galactosidase-II (pI=6.76), and β-galactosidase-III (pI=7.05). β-Galactosidase-III had exo-type galactanase activity, while the others did not.
      The activity of endo-type glycanases was a maximum in immature green or yellow fruits. The firmness of the pulp tissue decreased dramatically, and the amount of water-soluble polysaccharide (WSS) increased. The enzyme activities of exo-type glycosidases, especially β-galactosidase, appeared maximal in mature red fruits. The amount of extractable pectin remained unchanged, although the galactose content of the high-molecular-weight fraction in WSS decreased dramatically.
      These results suggest that the ripening of persimmon was caused by the solubilization of pectic polysaccharide by endo-type glycanases and digestion by exo-type glycosidases. β-Galactosidase, in particular, seemed to play a major role in ripening the fruit.
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  • Satoru NAKASHIMA, Shuji WAKATSUKI, Tatsuya YOKOYAMA, Manabu ARIOKA, Ka ...
    2003 Volume 67 Issue 1 Pages 77-82
    Published: 2003
    Released: June 25, 2003
    JOURNALS FREE ACCESS
      We previously showed that a fungal protein, p15, induces neurite outgrowth and differentiation of rat pheochromocytoma PC12 cells. We report here the identification and characterization of a protein similar to p15, found in Streptomyces coelicolor A3(2). This hypothetical protein, tentatively named Scp15, has significant similarity with p15, including conserved positions of four cysteine residues involved in the formation of essential disulfide bonds in p15. Hexahistidine-tagged recombinant Scp15 proteins were produced in Escherichia coli, purified, and analyzed for their neurite-inducing activity. Although they were less active than p15, they dose-dependently induced neurites and the expression of neurofilament M. Neurite outgrowth by Scp15 was inhibited by nicardipine, suggesting that Scp15 induces neurites via activation of a calcium signaling pathway.
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  • Kiyoshi ITO, Xiaohang MA, Nik AZMI, Hua-Shan HUANG, Mikio FUJII, Tadas ...
    2003 Volume 67 Issue 1 Pages 83-88
    Published: 2003
    Released: June 25, 2003
    JOURNALS FREE ACCESS
      Glycyl aminopeptidase was purified 600-fold from a cell extract of Actinomucor elegans by ammonium sulfate fractionation and sequential chromatography on DEAE-Toyopearl, Toyopearl HW65C, and FPLC-Superdex 200 HR, with recovery of 3.3% of the activity. The enzyme highly specifically hydrolyzed Gly-X (amino acid, peptide, or arylamide) bonds. The enzyme hydrolyzed other amino acid residues but at a rate of less than one fifth that with Gly. The order was Gly>>Ala>>Met>Arg>Ser>Leu. The Km value for glycyl-2-naphthylamide was 0.24 mM. The enzyme was most active at pH 8.0 with glycyl-2-naphthylamide as the substrate and its optimal temperature was 40°C. The enzyme was inhibited by iodoacetic acid, and p-chloromercuribenzoate but not done by diisopropylfluorophosphate, o-phenanthroline, or EDTA. Magnesium and calcium had no effect on enzymic activity, but the activity was suppressed by cadmium, zinc, and copper ions. The molecular mass was estimated to be 320 kDa by gel filtration on FPLC-Superdex 200 HR and 56.5 kDa by SDS-PAGE, so the enzyme probably was a hexamer.
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  • Shinya KAMAUCHI, Masashi YAMAGIWA, Motoyuki ESAKI, Kanao OTAKE, Hirosh ...
    2003 Volume 67 Issue 1 Pages 94-99
    Published: 2003
    Released: June 25, 2003
    JOURNALS FREE ACCESS
      The Cry1C δ-endotoxin from Bacillus thuringiensis is toxic to both lepidopteran and dipteran insect larvae. To analyze the dipteran-specific insecticidal mechanisms, we investigated the properties of Cry1C binding to the epithelial cell membrane of the larval midgut from the mosquito Culex pipiens in comparison with dipteran-specific Cry4A. Immunohistochemical staining of the larval midgut sections from Culex pipiens showed that Cry1C and Cry4A bound to the microvilli of the epithelial cells. The Cry1C binding to brush border membrane vesicles from the mosquito larvae was specific and irreversible, and did not compete with Cry4A. By ligand blotting analyses, we detected several Cry1C-binding proteins, the Cry1C binding to which did compete with excess unlabeled Cry4A. These results suggested that Cry1C and Cry4A recognized the same binding site(s) on the epithelial cell surface but that their interaction with the target membrane differed.
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  • Kentaro IFUKU, Yumiko YAMAMOTO, Fumihiko SATO
    2003 Volume 67 Issue 1 Pages 107-113
    Published: 2003
    Released: June 25, 2003
    JOURNALS FREE ACCESS
      RNA interference with double-stranded RNA is a new method for the study of gene function in various organisms. In this report, we show that an inverted repeat of a short (103-bp) 3′-untranslated sequence of an isogene, 1A, of psbP genes, encoded by a small multigene family of four genes (1A, 2AF, 3F, and 5B) in Nicotiana tabacum, can specifically suppress the expression of psbP isogenes 1A and 5B with a 3′-untranslated sequence similar to a transcribed double-stranded RNA. The expression of other psbP isogenes, 2AF and 3F, was not affected, although the coding sequences of the psbP family genes are highly conserved. Consistent with this observation, small interfering RNAs were detected for the 3′-untranslated sequence used for the inverted-repeat transgene, and not for the coding sequence. These results suggest that double-stranded RNA having a 3′-untranslated sequence could be useful for an isogene-specific RNA interference of the family genes in Nicotiana tabacum.
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  • Jeong-Jun YOON, Takefumi HATTORI, Mikio SHIMADA
    2003 Volume 67 Issue 1 Pages 114-120
    Published: 2003
    Released: June 25, 2003
    JOURNALS FREE ACCESS
      NADP-linked isocitrate dehydrogenase (EC 1.1.1.42), a key enzyme of the tricarboxylic acid cycle, was purified 672-fold as a nearly homogeneous protein from the copper-tolerant wood-rotting basidiomycete Fomitopsis palustris. The purified enzyme, with a molecular mass of 115 kDa, consisted of two 55-kDa subunits, and had the Km of 12.7, 2.9, and 23.9 μM for isocitrate, NADP, and Mg2+, respectively, at the optimal pH of 9.0. The enzyme had maximum activity in the presence of Mg2+, which also helped to prevent enzyme inactivation during the purification procedures and storage. The enzyme activity was competitively inhibited by 2-oxoglutarate (Ki, 127.0 μM). Although adenine nucleotides and other compounds, including some of the metabolic intermediates of glyoxylate and tricarboxylic acid cycles, had no or only slight inhibition, a mixture of oxaloacetate and glyoxylate potently inhibited the enzyme activity and the inhibition pattern was a mixed type.
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  • Hiroyasu ONAKA, Shin-ichi TANIGUCHI, Yasuhiro IGARASHI, Tamotsu FURUMA ...
    2003 Volume 67 Issue 1 Pages 127-138
    Published: 2003
    Released: June 25, 2003
    JOURNALS FREE ACCESS
      The biosynthetic gene cluster for rebeccamycin, an indolocarbazole antibiotic, from Lechevalieria aerocolonigenes ATCC 39243 has 11 ORFs. To clarify their functions, mutants with rebG, rebD, rebC, rebP, rebM, rebR, rebH, rebT, or orfD2 disrupted were constructed, and the gene products were examined. rebP disruptants produced 11,11′-dichlorochromopyrrolic acid, found to be a biosynthetic intermediate by a bioconversion experiment. Other genes encoded N-glycosyltransferase (rebG), monooxygenase (rebC), methyltransferase (rebM), a transcriptional activator (rebR), and halogenase (rebH). rebT disruptants produced rebeccamycin as much as the wild strain, so rebT was probably not involved in rebeccamycin production. Biosynthetic genes of staurosporine, an another indolocarbazole antibiotic, were cloned from Streptomyces sp. TP-A0274. staO, staD, and staP were similar to rebO, rebD, and rebP, respectively, all of which are responsible for indolocarbazole biosynthesis, But a rebC homolog, encoding a putative enzyme oxidizing the C-7 site of pyrrole rings, was not found in the staurosporine biosynthetic gene cluster. These results suggest that indolocarbazole is constructed by oxidative decarboxylation of chromopyrrolic acid (11,11′-dichlorochromopyrrolic acid in rebeccamycin) generated from two molecules of tryptophan by coupling and that the oxidation state at the C-7 position depends on the additional enzyme(s) encoded by the biosynthetic genes.
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  • Michiko NAKAMURA, Yoshiki KONO, Akira TAKATSUKI
    2003 Volume 67 Issue 1 Pages 139-150
    Published: 2003
    Released: June 25, 2003
    JOURNALS FREE ACCESS
      Mepanipyrim inhibited retrograde Golgi-to-ER trafficking induced by brefeldin A (BFA), nordihydroguaiaretic acid, clofibrate, and arachidonyltrifluoromethyl ketone in NRK and other types of cells, but did not inhibit anterograde trafficking of Golgi-resident proteins translocated to ER by BFA and newly synthesized VSV-G. However, mepanipyrim did not block the TGN38 dispersion induced by any of these compounds. Mepanipyrim acted on the Golgi, and swollen vesicular Golgi structures were formed and similar structures accumulated during rebuilding of the Golgi after BFA removal. These actions of mepanipyrim were readily reversed after its removal. Mepanipyrim did not stabilize microtubules, but prevented nocodazole-induced fragmentation and dispersion of the Golgi. These results suggest that the mepanipyrim-sensitive molecules participated in stabilizing the Golgi and its anchoring in the perinuclear region, and equally importantly, that the novel action of mepanipyrim may be used as a pharmacological tool for investigating membrane transport, Golgi membrane dynamics, and differentiation of the Golgi from TGN.
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  • Machiko NAKAMURA, Junko NAKAZAWA, Takeo USUI, Hiroyuki OSADA, Yoshiki ...
    2003 Volume 67 Issue 1 Pages 151-157
    Published: 2003
    Released: June 25, 2003
    JOURNALS FREE ACCESS
      Nordihydroguaiaretic acid (NDGA) protected microtubules in NRK cells from depolymerization caused by structurally and functionally diverse drugs such as nocodazole, colchicine, vinblastine, and ilimaquinone. Hitherto reported drugs, although structurally unrelated to paclitaxel, stabilize microtubules in a way similar to that of paclitaxel and compete for paclitaxel binding to tubulin. However, NDGA had activity toward microtubules different from the effects of paclitaxel. In NRK cells, paclitaxel caused microtubule bundle formation in the presence and absence of microtubule-depolymerizing drugs. However, microtubule bundle did not form, and microtubules radiated from the microtubule-organizing center, in cells treated with NDGA. Acceleration of tubulin polymerization in vitro by paclitaxel was strong but that by NDGA was weak. Microtubules polymerized in vitro in the presence of paclitaxel, but not those polymerized in the presence of NDGA, resisted the effects of cold. NDGA seemed to bind to tubulin, but did not compete for [3H]paclitaxel binding to tubulin. These observations indicate that NDGA belongs to a novel family of microtubule-stabilizing drugs.
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Biochemistry & Molecular Biology Notes
  • Akihito ISHIGAMI, Setsuko HANDA, Naoki MARUYAMA, Prakash C. SUPAKAR
    2003 Volume 67 Issue 1 Pages 158-160
    Published: 2003
    Released: June 25, 2003
    JOURNALS FREE ACCESS
      Senescence marker protein-30 (SMP30), expressed mostly in the liver, protects cells against various injuries by stimulating membrane calcium-pump activity. By immunohistochemistry and western blotting, we found that SMP30 was in both the nuclei and cytoplasm of cultured mouse hepatocytes. By a homology search, we found that a domain of the SMP30 sequence 51 amino acid residues long was 60-66% similar to bacterial and yeast RNA polymerases.
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  • Yasushi OKINAKA, Yukihisa SHIMADA, Ritsuko NAKANO-SHIMADA, Masaya OHBA ...
    2003 Volume 67 Issue 1 Pages 161-165
    Published: 2003
    Released: June 25, 2003
    JOURNALS FREE ACCESS
      Blue flowers generally contain 3′,5′-hydroxylated anthocyanins (delphinidin derivatives) as pigments, which are formed only in the presence of flavonoid 3′,5′-hydroxylases (F3′5′H). Heterologous expression of a F3′5′H gene therefore provides an opportunity to produce novel blue flowers for a number of ornamental plants missing blue flowering varieties. However, our previous study indicated difficulties in obtaining good accumulation of delphinidin derivatives in plants expressing F3′5′H. Here we report the isolation of a putative F3′5′H cDNA (Ka1) from canterbury bells (Campanula medium) and its expression in tobacco. Surprisingly, compared with other F3′5′H cDNAs, Ka1 encoded a protein with a unique primary structure that conferred high competence in the accumulation of delphinidin derivatives (up to 99% of total anthocyanins) and produced novel purple flowers. These results suggest that, among F3′5′H cDNAs, Ka1 is the best genetic resource for the creation of fine blue flowers by genetic engineering.
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  • Rintaro YAMANISHI, Ikuko YUSA, Noriko BANDO, Junji TERAO
    2003 Volume 67 Issue 1 Pages 166-169
    Published: 2003
    Released: June 25, 2003
    JOURNALS FREE ACCESS
      The IgE production was compared in the presence and absence of aluminum hydroxide gel (alum). Without alum, the IgE production was induced within a suitable range of the antigen dosage; however, alum enhanced it. Alum did not affect the minimum requirement for the antigen dosage, indicating that alum may not take part in the efficiency of antigen presentation.
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  • Tadanori AIMI, Hiroyuki TAGUCHI, Tsutomu MORINAGA
    2003 Volume 67 Issue 1 Pages 174-178
    Published: 2003
    Released: June 25, 2003
    JOURNALS FREE ACCESS
      The nucleotide sequence of the cytochrome c (CytC) gene of the white root rot fungus Rosellinia necatrix was analyzed. The structure of this gene, which had three introns in the coding region, was similar to that of Aspergillus nidulans. The second intron of the R. necatrix CytC gene was not present in Neurospora crassa or Fusarium oxysporum. However, the amino acid sequence of R. necatrix was most similar to that of Neurospora crassa. Thus, it seemed that the second intron of the R. necatrix CytC gene was inserted into its present position after R. necatrix and its closest relatives diverged evolutionarily.
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  • Makoto FUJIMURA, Noriyuki OCHIAI, Michiyo OSHIMA, Takayuki MOTOYAMA, A ...
    2003 Volume 67 Issue 1 Pages 186-191
    Published: 2003
    Released: June 25, 2003
    JOURNALS FREE ACCESS
      We cloned and characterized Neurospora NcSSK22 and NcPBS2 genes, similar to yeast SSK22 mitogen-activated protein (MAP) kinase kinase kinase and the PBS2 MAP kinase kinase genes, respectively. Disruptants of the NcSSK22 gene were sensitive to osmotic stress and resistant to iprodione and fludioxonil. Their phenotypes were similar to those of osmotic-sensitive (os) mutants os-1, os-2, os-4, and os-5. The os-4 mutant strain transformed with the wild-type NcSSK22 gene grew on a medium containing 4% NaCl and was sensitive to iprodione and fludioxonil. In contrast, the NcPBS2 gene complemented the osmotic sensitivity and fungicide resistance of the os-5 mutant strain. We sequenced the NcPBS2 gene of the os-5 mutant strain (NM216o) and found five nucleotides deleted within the kinase domain. This result suggests that the gene products of os-4 and os-5 are components of the MAP kinase cascade, which is probably regulated upstream by two-component histidine kinase encoded by the os-1/nik1 gene.
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  • Yuichiro IIDA, Yoshinori MATSUDA, Ryuichiro SAITO, Masanori NAKASATO, ...
    2003 Volume 67 Issue 1 Pages 198-202
    Published: 2003
    Released: June 25, 2003
    JOURNALS FREE ACCESS
      Overproduced proteins from Escherichia coli BL21(DE3) were efficiently released with virulent bacteriophages. Leviviridae-like bacteriophages were isolated from soil and used to lyse BL21(DE3) cells transformed with β-glucosidase, chitinase, or chitosanase genes. This method caused lysis of bacterial cells similar to that by conventional sonication and enabled us to effectively recover and purify the enzymes.
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  • Akiyoshi TANAKA, Hayuki SUGIMOTO, Yuko MUTA, Takafumi MIZUNO, Keishi S ...
    2003 Volume 67 Issue 1 Pages 207-210
    Published: 2003
    Released: June 25, 2003
    JOURNALS FREE ACCESS
      Thermal unfolding of P. cepacia lipase was observed by adiabatic differential scanning microcalorimetry in the absence and presence of calcium ions at pH 8, and thermodynamic parameters of unfolding were evaluated to analyze the unfolding mechanism of the enzyme. The temperature of unfolding was higher at higher concentrations of Ca2+. From the Ca2+ concentration-dependence of the unfolding temperature, the number of calcium ions that dissociated from the enzyme molecule upon unfolding was estimated to be one. These results confirmed the validity of the unfolding mechanism proposed previously: NCa2+↔D+Ca2+, where N and D represent the native and denatured states, respectively, of the enzyme.
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  • Shigeru CHOHNAN, Kayo AKAGI, Yoshichika TAKAMURA
    2003 Volume 67 Issue 1 Pages 214-217
    Published: 2003
    Released: June 25, 2003
    JOURNALS FREE ACCESS
      Malonate decarboxylase from Pseudomonas putida is composed of five subunits, α, β, γ, δ, and ε. Two subunits, δ and ε, have been identified as an acyl-carrier protein (ACP) and malonyl-CoA:ACP transacylase, respectively. Functions of the other three subunits have not been identified, because recombinant subunits expressed in Escherichia coli formed inclusion bodies. To resolve this problem, we used a coexpression system with GroEL/ES from E. coli, and obtained active recombinant subunits. Enzymatic analysis of the purified recombinant subunits showed that the α subunit was an acetyl-S-ACP:malonate ACP transferase and that the βγ-subunit complex was a malonyl-S-ACP decarboxylase.
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Biochemistry & Molecular Biology Preliminary Communication
  • Shuji KARASUDA, Shuhei TANAKA, Hiroshi KAJIHARA, Yuji YAMAMOTO, Daizo ...
    2003 Volume 67 Issue 1 Pages 221-224
    Published: 2003
    Released: June 25, 2003
    JOURNALS FREE ACCESS
      We investigated whether a plant chitinase can be used as a biocontrol agent instead of chemical fungicides by spraying chitinase E (family 19; class IV) from a yam (Dioscorea opposita Thunb) alone or together with β-1,3-glucanase directly onto the surface of a powdery mildew infecting strawberry berries and leaves. Results were observed by eye and with a scanning electron microscope. The powdery mildew infecting the strawberries was degraded, mainly by the chitinase, and the disease did not appear again for more than 2 weeks. These results indicated that this kind of plant chitinase might be safe and biodegradable biocontrol agent for use instead of conventional fungicides.
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Food & Nutrition Science Regular Papers
  • Kazunori KOBA, Jim-Wen LIU, Emil BOBIK, Jr., David E. MILLS, Michihiro ...
    2003 Volume 67 Issue 1 Pages 15-22
    Published: 2003
    Released: June 25, 2003
    JOURNALS FREE ACCESS
      Dietary soy protein, in comparison with casein, generally lowers the serum cholesterol concentration in rats fed on a cholesterol-enriched diet, while mixed results were observed in rats fed on a diet free of cholesterol. Soy protein also suppresses the conversion of linoleic acid to arachidonic acid in the rat liver. The present study examines whether phytate, a minor component of a soy protein isolate, is responsible for these beneficial effects of soy protein. Weanling male rats were fed for 4 weeks on a purified diet containing a 20% level of protein (either casein (CAS), soy protein (SOY), phytate-depleted SOY (PDSOY) or phytate-replenished PDSOY (PRSOY)) and cholesterol (0 or 0.5%). The dietary protein source and phytate level only affected the serum and liver cholesterol concentrations when the animals were fed on the cholesterol-enriched diet, being significantly lower in those rats fed on the SOY and PRSOY diets than in those fed on the CAS diet, while the concentrations in the rats fed on the PDSOY diet were intermediate. When the animals were fed on the cholesterol-free diet, the ratio of (20:3n-6+20:4n-6)/18:2n-6 in liver phosphatidylcholine, a Δ6 desaturation index, was significantly lower in the SOY diet group than in the CAS, PDSOY and PRSOY diet groups. Dietary cholesterol significantly depressed the ratio, but neither depletion nor replenishment of phytate affected the ratio. These results suggest that phytate in soy protein played a limited role in the cholesterol-lowering effect of soy protein and was not involved in the metabolism of linoleic acid.
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  • Gaku HIBINO, Tomonori NADAMOTO, Fumiko FUJISAWA, Tohru FUSHIKI
    2003 Volume 67 Issue 1 Pages 23-28
    Published: 2003
    Released: June 25, 2003
    JOURNALS FREE ACCESS
      We investigated whether the ingestion of the Japanese persimmon (kaki, Diospyros kaki) could lower the human peripheral body temperature. It was found that the temperatures recorded at the foot and wrist were depressed after kaki consumption compared to after the same amount of water consumption. The effects of ingesting freeze-dried kaki and eating a cookie (as its nutritional counterpart) containing the same amount of carbohydrate, protein, fat, and water were compared. A similar temperature-reducing effect of kaki was observed. The recovery of finger temperature after soaking the finger in ice-cooled water was also studied. The temperature recovery was delayed after kaki consumption. It was thus quantitatively demonstrated that ingesting kaki indeed had the effect of lowering (or repressing the rise) of the peripheral human body temperature, as has been traditionally believed in China for many hundreds of years.
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  • Michio KASAI, Hideaki MAKI, Naohisa NOSAKA, Toshiaki AOYAMA, Katsuhiko ...
    2003 Volume 67 Issue 1 Pages 46-53
    Published: 2003
    Released: June 25, 2003
    JOURNALS FREE ACCESS
      This study compared the serum lipid concentrations after a single dose of medium-chain triglycerides (MCT) or long-chain triglycerides (LCT) between individuals grouped according to the body mass index (BMI). Twenty-five males participated as volunteers, the test diet containing 10 g of MCT or LCT. Blood samples were collected up to 6 h after the intake of a test diets. The LCT diet resulted in significantly greater increases in areas under the curves (AUCs) for serum and chylomicron triglyceride in the BMI≥23 kg/m2 group than those in the BMI<23 kg/m2 group. The magnitude of response after intake of the MCT diet by the BMI≥23 kg/m2 group was significantly lower than that after the LCT diet. These results suggest that, in subjects with BMI≥23 kg/m2, the intake of MCT is preferable to that of LCT for maintaining postprandial triglyceride at a low concentration.
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  • Satomi SHIZUUCHI, Fumitaka HAYASE
    2003 Volume 67 Issue 1 Pages 54-59
    Published: 2003
    Released: June 25, 2003
    JOURNALS FREE ACCESS
      A blue compound was prepared from 1 M D-xylose and 0.1 M glycine, and designated Blue-M1, an intermediate color product of melanoidins. As melanoidins are well known to have antioxidative activity as well as high scavenging activity against active oxygen species, the antioxidative activity of Blue-M1 against the peroxidation of linoleic acid was investigated, in addition to the scavenging activity of Blue-M1 toward hydroxyl and DPPH radicals.
      Blue-M1 suppressed the peroxidation of linoleic acid as effectively as melanoidins did. The scavenging activity of Blue-M1 toward hydroxyl and DPPH radicals was also as strong as that of melanoidins. Blue-M1 showed higher activity with increasing concentration. The pyrrolopyrrole ring and a methine bridge between two pyrrolopyrrole rings in Blue-M1 could be related to the ability for radical scavenging activity, but not four carboxyl groups.
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  • Satoru SHIMIZU, Masuo NAKANO
    2003 Volume 67 Issue 1 Pages 60-67
    Published: 2003
    Released: June 25, 2003
    JOURNALS FREE ACCESS
      The differences are reported in the triacylglycerol (TG) structures of oils containing gamma-linolenic acid (GLA) from Oenothera biennis Linn seed oil (OBLO) from the wild plant, evening primrose seed oil (EPO) from a cultured plant, and bio-GLA oil (BIO) from a mold, the physiological functions of which were ascertained by animal testing.
      Reverse-phase high-performance liquid chromatographic separation detected 12 TG peaks each for OBLO and EPO, and 28 TG peaks for BIO. TG-containing GLA were composed of five molecular species each in OBLO and EPO, and ten molecular species in BIO. The totals of the molecular species containing GLA were 29.8% in OBLO, 23.8% in EPO, and 56.6% in BIO. In OBLO, the GLA level at the sn-2 position of the major TG species was higher than that in EPO. In BIO, the GLA level at the sn-2 position of the major TG species was lower than those in OBLO and EPO.
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  • Yoshiko SUGITA-KONISHI, Kazuo KOBAYASHI, Hiroyuki NAITO, Katuhiro MIUR ...
    2003 Volume 67 Issue 1 Pages 89-93
    Published: 2003
    Released: June 25, 2003
    JOURNALS FREE ACCESS
      We studied the effect of lactational exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) on the susceptibility to Listeria infection of offspring in C57BL/6NCji mice. The offspring were nursed by TCDD-treated dams and exposed to TCDD from birth to weaning via milk. The exposure had little effect on the weights of immune organs and the spleen or the thymus cell population in the dams and offspring, but it enhanced the production of tumor necrosis factor alpha (TNF-α) and interferon gamma (IFN-γ) in the serum after Listeria infection. The clearance of Listeria monocytogenes from the spleen was impaired in the offspring. These results suggest that the exposure to TCDD of the offspring via milk disrupted the host resistance of the offspring, even though the main immune parameters were unchanged.
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Food & Nutrition Science Note
Microbiology & Fermentation Technology Regular Papers
  • Shinya KURATA, Kazutaka YAMADA, Kyoko TAKATSU, Satoshi HANADA, Osamu K ...
    2003 Volume 67 Issue 1 Pages 8-14
    Published: 2003
    Released: June 25, 2003
    JOURNALS FREE ACCESS
      A two-membered coculture of strains KYM-7 and KYM-8, identified as Cellulomonas cellulans and Agrobacterium tumefaciens, respectively, produced a large amount of an extracellular polysaccharide, designated APK-78, from starch. Each strain in pure culture produced only very little amount of polysaccharide from starch; the coexistence of the two strains from the early stage of cultivation was indispensable for a large amount of polysaccharide to be produced. The polysaccharide APK-78 was acidic and composed of glucose, galactose, succinic acid, and pyruvic acid with a molar ratio of 8.1:1.0:1.7:1.0, indicating that it is a succinoglycan type of polysaccharide.
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  • Hideaki NOJIRI, Hiroko TAIRA, Kenichi IWATA, Kenichi MORII, Jeong-Won ...
    2003 Volume 67 Issue 1 Pages 36-45
    Published: 2003
    Released: June 25, 2003
    JOURNALS FREE ACCESS
      2-Hydroxy-6-oxo-6-(2′-aminophenyl)-hexa-2,4- dienoic acid [6-(2′-aminophenyl)-HODA] hydrolase, involved in carbazole degradation by Pseudomonas resinovorans strain CA10, was purified to near homogeneity from an overexpressing Escherichia coli strain. The enzyme was dimeric, and its optimum pH was 7.0-7.5. Phylogenetic analysis showed the close relationship of this enzyme to other hydrolases involved in the degradation of monocyclic aromatic compounds, and this enzyme was specific for 2-hydroxy-6-oxo-6-phenylhexa-2,4-dienoic acid (6-phenyl-HODA), having little activity toward 2-hydroxy-6-oxohepta-2,4-dienoic acid and 2-hydroxymuconic semialdehyde. The enzyme had a Km of 2.51 μM and kcat of 2.14 (s−1) for 6-phenyl-HODA (50 mM sodium phosphate, pH 7.5, 25°C). The effect of the presence of an amino group or hydroxyl group at the 2′-position of phenyl moiety of 6-phenyl-HODA on the enzyme activity was found to be small; the activity decreased only in the order of 6-(2′-aminophenyl)-HODA (2.44 U/mg)>6-phenyl-HODA (1.99 U/mg)>2-hydroxy-6-oxo-6-(2′-hydroxyphenyl)-hexa-2,4-dienoic acid (1.05 U/mg). The effects of 2′-substitution on the activity were in accordance with the predicted reactivity based on the calculated lowest unoccupied molecular orbital energy for these substrates.
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  • Katsuhiko BABASAKI, Kazuhiko MASUNO, Hitoshi MURATA
    2003 Volume 67 Issue 1 Pages 100-106
    Published: 2003
    Released: June 25, 2003
    JOURNALS FREE ACCESS
      The spawn of cultivated mushrooms are generally produced, propagated, and distributed to growers as a mycelial culture without genetic purification, in which phenotypic variants frequently occur. We investigated how heterologous mycelia present in a spawn influence fruit body production in the cultivated basidiomycete Pholiota nameko. The ‘di-mon’ dual cultivation of protoplast clones produced mosaic fruit bodies, which could result from the ‘di-mon’ mating. In the ‘di-di’ dual cultivation of heterologous strains with different fruiting times, authentic fruit bodies of each dikaryon and chimera showing a feature combining characteristics of the two dikaryons emerged simultaneously. Mycelia isolated from the chimera produced all three types of fruit bodies, indicating unlikeliness of the occurrence of anastomosis. These results suggest that mycelia colonized in the substrate interact with each other and coordinately promote fruit body production in P. nameko. This phenomenon masks a clonal variability that may be surfaced through multiplication and distribution of the spawn, occasionally bringing about abnormal fruiting.
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  • Norio HASEGAWA, Hiroyuki ARAI, Yasuo IGARASHI
    2003 Volume 67 Issue 1 Pages 121-126
    Published: 2003
    Released: June 25, 2003
    JOURNALS FREE ACCESS
      Pseudomonas aeruginosa strains deficient in the genes for cytochrome c1, a subunit of the cytochrome bc1 complex, or the tetraheme membrane protein NapC, which is similar to NirT of Pseudomonas stutzeri, were constructed and their growth was investigated. The cytochrome c1 mutant could not grow under anaerobic conditions with nitrite as an electron acceptor and did not reduce nitrite in spite of its producing active nitrite reductase. NirM (cytochrome c551) and azurin, which are the direct electron donors for nitrite reductase, were reduced by succinate in the presence of the membrane fraction from the wild-type strain as a mediator but not in the presence of that from the cytochrome c1 mutant. These results indicated that cytochrome bc1 complex was necessary for electron transfer from the membrane quinone pool to nitrite reductase. The NapC mutant grew anaerobically at the expense of nitrite, indicating that NapC was not necessary for nitrite reduction.
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Microbiology & Fermentation Technology Notes
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