Bioscience, Biotechnology, and Biochemistry
Online ISSN : 1347-6947
Print ISSN : 0916-8451
Volume 74 , Issue 11
Showing 1-40 articles out of 40 articles from the selected issue
Analytical Chemistry Regular Paper
Organic Chemistry Regular Paper
  • Tetsu TSURUSHIMA, Yukari MINAMI, Hisashi MIYAGAWA, Hitoshi NAKAYASHIKI ...
    2010 Volume 74 Issue 11 Pages 2220-2225
    Published: November 23, 2010
    Released: November 23, 2010
    [Advance publication] Released: November 07, 2010
    JOURNALS FREE ACCESS
    The ethyl acetate extract of the conidia germination fluid from an Avena isolate (Br58) of Pyricularia oryzae had chlorosis-inducing activity on oat leaf segments. The same activity was also present in the acetone extract of an oatmeal agar culture of Br58. Fungal cultures were used for a large-scale preparation. A series of acetone and ethyl acetate extraction monitored by chromatography was used to isolate an active fraction. The active principle was purified by HPLC. We show by NMR and LC/MS that the toxin was an oxidized C18 unsaturated fatty acid named Mag-toxin. Mag-toxin induced chlorosis on oat leaf segments incubated in the light but not in the dark. Reactive oxygen species (ROS) and cell death were induced by Mag-toxin in oat cells. The sub-cellular localization of ROS generation induced by the toxin treatment was correlated with the location of mitochondria. Interestingly, the induction of ROS generation and cell death by Mag-toxin was light-independent.
    Download PDF (351K)
Organic Chemistry Notes
Biochemistry & Molecular Biology Regular Papers
  • Jia-Hong ZHU, Xin CHEN, Wen-Jun CHANG, Wei-Min TIAN, Zhi-Li ZHANG
    2010 Volume 74 Issue 11 Pages 2183-2188
    Published: November 23, 2010
    Released: November 23, 2010
    [Advance publication] Released: November 07, 2010
    JOURNALS FREE ACCESS
    Calcium-dependent protein kinases (CDPKs), as major primary Ca2+ sensors, have been implicated in the regulation of stress and developmental signals in plants. In this study, a novel CDPK gene, designated HbCDPK1, was isolated from Hevea brasiliensis. The HbCDPK1 cDNA had 2,400 bp with an open reading frame of 1,671 bp encoding 556 amino acids, and the deduced HbCDPK1 protein contained four characteristic domains identified in CDPKs, showing a high level of sequence similarity to CDPKs from other plants. Expression analysis revealed more significant accumulation of the transcripts of HbCDPK1 in latex than in the leaves, bark, and roots in H. brasiliensis. In addition, transcription of HbCDPK1 was strongly induced by mechanical wounding, jasmonic acid (JA), and ethephon. Recombinant HbCDPK1 was expressed in E. coli, and its activity was assayed. The assay indicated that HbCDPK1 had the kinase and Ca2+-binding activity in vitro as a calcium-dependent protein. The potential roles of the HbCDPK1 are discussed as to latex production and rubber biosynthesis.
    Download PDF (428K)
  • Ya-Dong GE, Zheng-Yu CAO, Zong-Da WANG, Lu-Lu CHEN, You-Ming ZHU, Guo- ...
    2010 Volume 74 Issue 11 Pages 2194-2201
    Published: November 23, 2010
    Released: November 23, 2010
    [Advance publication] Released: November 07, 2010
    JOURNALS FREE ACCESS
    We identified and characterized a malate dehydrogenase from Streptomyces coelicolor A3(2) (ScMDH). The molecular mass of ScMDH was 73,353.5 Da with two 36,675.0 Da subunits as analyzed by matrix-assisted laser-desorption ionization–time-of-flight mass spectrometry (MALDI-TOF-MS). The detailed kinetic parameters of recombinant ScMDH are reported here. Heat inactivation studies showed that ScMDH was more thermostable than most MDHs from other organisms, except for a few extremely thermophile bacteria. Recombinant ScMDH was highly NAD+-specific and displayed about 400-fold (kcat) and 1,050-fold (kcatKm) preferences for oxaloacetate reduction over malate oxidation. Substrate inhibition studies showed that ScMDH activity was inhibited by excess oxaloacetate (Ki=5.8 mM) and excess L-malate (Ki=12.8 mM). Moreover, ScMDH activity was not affected by most metal ions, but was strongly inhibited by Fe2+ and Zn2+. Taken together, our findings indicate that ScMDH is significantly thermostable and presents a remarkably high catalytic efficiency for malate synthesis.
    Download PDF (447K)
  • Ok-Joo SUL, Jin-Chun KIM, Tae-Wook KYUNG, Hye-Jin KIM, Youn-Young KIM, ...
    2010 Volume 74 Issue 11 Pages 2209-2213
    Published: November 23, 2010
    Released: November 23, 2010
    [Advance publication] Released: November 07, 2010
    JOURNALS FREE ACCESS
    Gold nanoparticles inhibited osteoclast (OC) formation induced by the receptor activator of nuclear factor-κB ligand (RANKL) in bone marrow-derived macrophages (BMMs). This was accompanied by a decreased level of tartrate-resistant alkaline phosphatase (TRAP) and less activation of nuclear factor (NF)-κB. The nanoparticles also reduced the production of reactive oxygen species (ROS) in response to RANKL and upregulated RANKL-induced glutathione peroxidase-1 (Gpx-1), suggesting a role as an antioxidant in the BMM. The inhibitory effects on OC formation might have been due to elevated defense against oxidative stress.
    Download PDF (145K)
  • Takayasu KAWASAKI, Kenji ONODERA, Shunsuke KAMIJO
    2010 Volume 74 Issue 11 Pages 2214-2219
    Published: November 23, 2010
    Released: November 23, 2010
    [Advance publication] Released: November 07, 2010
    JOURNALS FREE ACCESS
    Supplementary material
    There have been many reports suggesting that soluble oligomers of amyloid β (Aβ) are neurotoxins causing Alzheimer’s disease (AD). Although inhibition of the soluble oligomerization of Aβ is considered to be effective in the treatment of AD, almost all peptide inhibitors have been designed from the β-sheet structure (H14-D23) of Aβ1-42. To obtain more potent peptides than the known inhibitors of the soluble-oligomer formation of Aβ1-42, we performed random screening by phage display. After fifth-round panning of a hepta-peptide library against soluble Aβ1-42, novel peptides containing arginine residues were enriched. These peptides were found to suppress specifically 37/48 kDa oligomer formation and to keep the monomeric form of Aβ1-42 even after 24 h of incubation, as disclosed by SDS–PAGE and size-exclusion chromatography. Thus we succeeded in acquiring novel efficient peptides for inhibition of soluble 37/48 kDa oligomer formation of Aβ1-42.
    Download PDF (218K)
  • Bo ZENG, Hongning WANG, Likou ZOU, Anyun ZHANG, Xin YANG, Zhongbin GUA ...
    2010 Volume 74 Issue 11 Pages 2237-2241
    Published: November 23, 2010
    Released: November 23, 2010
    [Advance publication] Released: November 07, 2010
    JOURNALS FREE ACCESS
    Indole derivatives 3-amino-6-carboxyl-indole and 3-nitro-6-amino-indole were designed and synthesized based on the TolC structure. They proved to have potent synergistic antibacterial effects on chloramphenicol, tetracycline, erythromycin, and ciprofloxacin against Escherichia coli YD2 and FJ307 with decreased minimal inhibitory concentrations (MICs) at 2–64 folds. To research its functional site, Escherichia coli BL21(DE3)−3 expressing a target-site mutated TolC was constructed by red homologous recombination and the site-directed mutagenesis technique. They did not noticeably affect antimicrobial activity against BL21(DE3)−3. All the results indicate that these compounds match our design and can be developed as efflux pump inhibitors for the AcrAB-TolC efflux pump.
    Download PDF (126K)
  • Takuya TSUBOTA, Takayo NAKAKURA, Tetsuro SHINODA, Takahiro SHIOTSUKI
    2010 Volume 74 Issue 11 Pages 2259-2266
    Published: November 23, 2010
    Released: November 23, 2010
    [Advance publication] Released: November 07, 2010
    JOURNALS FREE ACCESS
    Juvenile hormone esterases (JHEs) function in juvenile hormone (JH) degradation. In the silkworm, Bombyx mori, we have characterized authentic JHE (Bmjhe) and five other carboxyl/cholinesterase (CCE) genes (Bmcce-1 to -5) with GQSAG, a motif sequence of JHE. But none of the genes appeared to function in vivo as a JHE, except for Bmjhe. Recently it was reported that the GQSAG motif might be dispensable, and that the Thr-316 residue has functional significance for JHE activity. On the basis of these findings, we identified two novel JHE candidates, Bmcce-6 and Bmcce-7, that lack GQSAG but possess Thr-316. In the CCE phylogenetic tree, BmCCE-6 was close to the lepidopteran JHE cluster, while BmCCE-7 constituted the same cluster as pheromone-degrading esterases. The developmental expression profiles were different among Bmjhe, Bmcce-6, and Bmcce-7. None of the proteins hydrolyzed JH in vitro. Our results suggest that only one CCE (BmJHE) functions as JHE in the silkworm.
    Download PDF (5761K)
  • Pham Ngoc CHIEN, Ji-Young MOON, Jun-Haeng CHO, Soo-Jae LEE, Joon-Shik ...
    2010 Volume 74 Issue 11 Pages 2281-2286
    Published: November 23, 2010
    Released: November 23, 2010
    [Advance publication] Released: November 07, 2010
    JOURNALS FREE ACCESS
    The first step in branched-chain amino acid biosynthesis is catalyzed by acetohydroxyacid synthase (EC 2.2.1.6). This reaction involves decarboxylation of pyruvate followed by condensation with either an additional pyruvate molecule or with 2-oxobutyrate. The enzyme requires three cofactors, thiamine diphosphate (ThDP), a divalent ion, and flavin adenine dinucleotide (FAD). Escherichia coli contains three active isoenzymes, and acetohydroxyacid synthase I (AHAS I) large subunit is encoded by the ilvB gene. In this study, the ilvB gene from E. coli K-12 was cloned into expression vector pETDuet-1, and was expressed in E. coli BL21 (DH3). The purified protein was identified on a 12% SDS–PAGE gel as a single band with a mass of 65 kDa. The optimum temperature, buffer, and pH for E. coli K-12 AHAS I were 37 °C, potassium phosphate buffer, and 7.5. Km values for E. coli K-12 AHAS I binding to pyruvate, Mg+2, ThDP, and FAD were 4.15, 1.26, 0.2 mM, and 0.61 μM respectively. Inhibition of purified AHAS I protein was determined with herbicides and new compounds.
    Download PDF (223K)
  • Makoto OGATA, Takakiyo OBARA, Yasushi CHUMA, Takeomi MURATA, Enoch Y. ...
    2010 Volume 74 Issue 11 Pages 2287-2292
    Published: November 23, 2010
    Released: November 23, 2010
    [Advance publication] Released: November 07, 2010
    JOURNALS FREE ACCESS
    A series of dansyl-labeled glycosides with di-, tetra-, and hexasaccharides carrying the terminal N-acetyllactosamine (LacNAc) sequence were synthesized as acceptor substrates for α2,6- and α2,3-sialyltransferases. As an alternative design, dansyl-labeled LacNAc glycoside carrying a long-spacer linked glycan was engineered by replacement of the LacNAc or lactose units with an alkyl chain. In addition, we designed a dansyl-labeled bi-antennary LacNAc glycoside as an N-linked oligosaccharide mimetic, such as asialo-α1-acid glycoprotein. The kinetic parameters for the transfer reaction of synthesized dansyl-labeled glycosides by sialyltransferases were determined by the fluorescent HPLC method. The catalytic efficiencies (Vmax/Km) of acceptor substrates carrying the terminal LacNAc sequence with various length glycans in the array for α2,6- and α2,3-sialyltransferases decreased in a glycan length-dependent manner. Furthermore, of the acceptor substrates tested, dansyl-labeled bi-antennary LacNAc glycoside displayed the most favorable Km value for α2,6- and α2,3-sialyltransferases.
    Download PDF (252K)
  • Masao MIYAZAKI, Hiroaki SEGAWA, Tetsuro YAMASHITA, Yafeng ZHU, Kaoru T ...
    2010 Volume 74 Issue 11 Pages 2293-2298
    Published: November 23, 2010
    Released: November 23, 2010
    [Advance publication] Released: November 07, 2010
    JOURNALS FREE ACCESS
    Supplementary material
    Sendai virus (SeV) is an enveloped virus with a non-segmented negative-strand RNA genome. SeV envelope fusion (F) glycoproteins play crucial roles in the viral life cycle in processes such as viral binding, assembly, and budding. In this study, we developed a viable recombinant SeV designated F-EGFP SeV/ΔF, in which the F protein was replaced by an F protein fused to EGFP at the carboxyl terminus. Living infected cells of the recombinant virus were directly visualized by green fluorescence. The addition of EGFP to the F protein maintained the activities of the F protein in terms of intracellular transport to the plasma membrane via the ER and the Golgi apparatus and fusion activity in the infected cells. These results suggest that this fluorescent SeV is a useful tool for studying the viral binding, assembly, and budding mechanisms of F proteins and the SeV life cycle in living infected cells.
    Download PDF (453K)
Biochemistry & Molecular Biology Notes
Biochemistry & Molecular Biology Communication
  • Kenji GOUDA, Yohei MATSUNAGA, Takashi IWASAKI, Tsuyoshi KAWANO
    2010 Volume 74 Issue 11 Pages 2361-2365
    Published: November 23, 2010
    Released: November 23, 2010
    [Advance publication] Released: November 07, 2010
    JOURNALS FREE ACCESS
    In reverse genetics, RNA interference (RNAi) which is substitutable for gene-disruption, is an outstanding method for knockdown of a gene’s function. In Caenorhabditis elegans, feeding RNAi is most convenient, but this RNAi is not suitable for knockdown of multiple genes. Hence, we attempted to establish an efficient method of feeding RNAi for multiple knockdown. We produced bacteria yielding three distinct double-stranded RNAs bound to one another, and fed those bacteria to C. elegans. Quantitative RT-PCR and observation of phenotypes indicated that our method is much more efficient than the traditional one. Our method is useful for investigating genes’ functions in C. elegans.
    Download PDF (211K)
Food & Nutrition Science Regular Papers
  • Wichai CHERDSHEWASART, Tawatchai MAHAPANICHKUL, Chuenchit BOONCHIRD
    2010 Volume 74 Issue 11 Pages 2176-2182
    Published: November 23, 2010
    Released: November 23, 2010
    [Advance publication] Released: November 07, 2010
    JOURNALS FREE ACCESS
    This study evaluated the estrogenic and antiestrogenic activities of native and in vitro hepatic metabolized tuberous extracts of wild Butea superba collected from 23 out of the 76 provinces in Thailand by yeast estrogen screening (YES). The YES screen used consisted of the human estrogen receptors hERα and hERβ and the human transcriptional intermediary factor 2 or human steroid receptor coactivator 1, respectively, together with the β-galactosidase expression cassette as the reporter. The relative potency, effectiveness and relative inductive efficiency were evaluated by determining the β-galactosidase activity (EC50) of each tuberous extract in relation to that induced by 17β-estradiol. Six pure compounds isolated from B. superba were tested in parallel and exhibited a maximum relative potency compared to 17β-estradiol of 15.5% and 5.27% in the respective hERα and hERβ assays. Eighteen and seventeen plant extracts were respectively found to interact with the hERα and hERβ receptors in the YES assays with higher relative potency and relative inductive efficiency with hERβ than with hERα. The selected plant extracts tested exhibited antiestrogenic activity. Coincubation with the rat liver S9 mixture also elevated the estrogenic potency of these plant extracts.
    Download PDF (178K)
  • Momoko KITAOKA, Takuya WADA, Takeshi NISHIO, Masahiro GOTO
    2010 Volume 74 Issue 11 Pages 2189-2193
    Published: November 23, 2010
    Released: November 23, 2010
    [Advance publication] Released: November 07, 2010
    JOURNALS FREE ACCESS
    Supplementary material
    A rapid and easy method to discriminate plant cultivars is indispensable to confirm food labeling. We established a fluorogenic ribonuclease protection (FRIP) assay to discriminate Japanese rice (Oryza sativa L.) cultivars based on single nucleotide polymorphisms (SNPs). The FRIP assay uses a hybridization technique between fluorescent probes and the target sequence prepared by run-off transcription, but the requirement of two PCR thermocycles is the problem when preparing template DNA for run-off transcription from rice genomic DNA. In this study, we designed new PCR primers with asymmetric melting temperatures. These primers amplified the target SNP marker containing a T7 RNA polymerase promoter sequence upstream of the target sequence in a single PCR. Moreover, 100 cultivars were discriminated with the patterns of 15 SNPs. The assay can be used as a rapid method of analysis to discriminate Japanese rice cultivars.
    Download PDF (244K)
  • Hiroshi UEDA, Katsunari IPPOUSHI, Atsuko TAKEUCHI
    2010 Volume 74 Issue 11 Pages 2248-2252
    Published: November 23, 2010
    Released: November 23, 2010
    [Advance publication] Released: November 07, 2010
    JOURNALS FREE ACCESS
    We investigated the ability of a ginger extract to induce an immune response in RAW 264 cells and after a repeated oral administration to mice. The squeezed ginger extract augmented the production of tumor necrosis factor-α, interleukin-6, and monocyte chemotactic protein-1 when added to RAW 264 cells. This extract was collected as its ethanol-insoluble fraction. The oral administration of the squeezed ginger extract or its ethanol-insoluble fraction once or twice to mice also augmented the tumor necrosis factor-α production in peritoneal cells; however, its long-term administration had the opposite effect. The serum corticosterone level had increased after orally administering the squeezed ginger extract and was maintained during the administration period. Oral administration of the squeezed ginger extract also inhibited arachidonic acid-induced ear edema, but its repeated administration was needed to achieve an anti-inflammatory effect. These results suggest that the repeated administration of the aqueous constituents of ginger augmented the serum corticosterone level and that this may have gradually induced anti-inflammatory activity.
    Download PDF (312K)
  • Ichiro SHIRASUGI, Yoichi SAKAKIBARA, Masao YAMASAKI, Kazuo NISHIYAMA, ...
    2010 Volume 74 Issue 11 Pages 2253-2258
    Published: November 23, 2010
    Released: November 23, 2010
    [Advance publication] Released: November 07, 2010
    JOURNALS FREE ACCESS
    Measurement of the melanin content by using B16 melanoma cells is generally applied to find novel skin-whitening agents. However, this measurement method using B16 melanoma cells has such disadvantages, as the time taken, its sensitivity, and troublesomeness. We therefore attempted in the present study to establish a reporter assay system by measuring the tyrosinase promoter activity to use for convenient, high-throughput screening of new melanogenesis inhibitors. We first confirmed the validity of this reporter assay system by using such known skin-whitening agents, as arbutin, sulforaphane, and theaflavin 3,3′-digallate. We then compared the effect of 56 compounds on the tyrosinase promoter activity to test this reporter assay system. Carnosol, and rottlerin strongly inhibited the tyrosinase promoter activity. Moreover, carnosol and rottlerin decreased melanin synthesis and tyrosinase expression in a dose-dependent manner when using B16 melanoma cells. These results indicate this new luciferase reported assay system to be an effective and convenient method for screening potential skin-whitening compounds.
    Download PDF (153K)
  • Ah Jin KIM, Jung Nam CHOI, Jiyoung KIM, Sait Byul PARK, Soo Hwan YEO, ...
    2010 Volume 74 Issue 11 Pages 2267-2272
    Published: November 23, 2010
    Released: November 23, 2010
    [Advance publication] Released: November 07, 2010
    JOURNALS FREE ACCESS
    Supplementary material
    In this study, Aspergillus kawachii, Aspergillus oryzae, and Rhizopus sp., were utilized for rice Koji fermentation, and the metabolites were analyzed in a time-dependent manner by gas chromatography-mass spectrometry. On Principal Component Analysis, the metabolite patterns were clearly distinguished based on the fungi species. This approach revealed that the quantities of glucose, galactose, and glycerol gradually increased as a function of fermentation time in all trials rice Koji fermentation. The time-dependent changes of these metabolites showed significant increases in glucose in the A. oryzae-treated rice, and in glycerol and galactose in the A. kawachii-treated rice. In addition, glycolysis-related enzyme activities were correlated with the changes in these metabolites. The results indicate that time-dependent metabolite production has the potential to be a valuable tool in selecting inoculant fungi and the optimal fermentation time for rice koji.
    Download PDF (316K)
  • Nakaba MURATA, Kazuma MURAKAMI, Yusuke OZAWA, Noriaki KINOSHITA, Kazuh ...
    2010 Volume 74 Issue 11 Pages 2299-2306
    Published: November 23, 2010
    Released: November 23, 2010
    [Advance publication] Released: November 07, 2010
    JOURNALS FREE ACCESS
    Supplementary material
    Alzheimer’s disease (AD) is characterized by progressive cognitive impairment and the formation of senile plaques. Silymarin, an extract of milk thistle, has long been used as a medicinal herb for liver diseases. Here we report marked suppression of amyloid β-protein (Aβ) fibril formation and neurotoxicity in PC12 cells after silymarin treatment in vitro. In vivo studies had indicated a significant reduction in brain Aβ deposition and improvement in behavioral abnormalities in amyloid precursor protein (APP) transgenic mice that had been preventively treated with a powdered diet containing 0.1% silymarin for 6 months. The silymarin-treated APP mice also showed less anxiety than the vehicle-treated APP mice. These behavioral changes were associated with a decline in Aβ oligomer production induced by silymarin intake. These results suggest that silymarin is a promising agent for the prevention of AD.
    Download PDF (316K)
Food & Nutrition Science Notes
Microbiology & Fermentation Technology Regular Papers
  • Toshinori IGARASHI
    2010 Volume 74 Issue 11 Pages 2171-2175
    Published: November 23, 2010
    Released: November 23, 2010
    [Advance publication] Released: November 07, 2010
    JOURNALS FREE ACCESS
    One hundred and seventeen strains of plant origin lactic acid bacteria were observed to have interleukin (IL)-12 production-inducing activities using mouse peritoneal macrophages. Pediococcus pentosaceus (KKM122) was chosen for its stable and strong IL-12 production-inducing activity. There was no significant difference in IL-12 activity induced by the KKM122 strain grown in culture conditions of 0% and 6% NaCl. The cell wall components of cells grown in 6% salt condition, however, significantly induced lower IL-12 production as compared with those of cells grown in 0% salt condition. Cell wall components enhanced IL-12 activity by removing cytoplasmic components when KKM122 strain was cultured in 0% salt condition. The immunoenhancing factor was mainly present in the cell wall components. IL-12 production-inducing activities were dependent on both the amount of bacterial cytoplasmic components and the structure of the cell wall components under the NaCl concentration in the culture medium.
    Download PDF (199K)
  • Tsuyoshi SUGIO, Ami AKO, Fumiaki TAKEUCHI
    2010 Volume 74 Issue 11 Pages 2242-2247
    Published: November 23, 2010
    Released: November 23, 2010
    [Advance publication] Released: November 07, 2010
    JOURNALS FREE ACCESS
    Sulfite is produced as a toxic intermediate during Acidithiobacillus ferrooxidans sulfur oxidation. A. ferrooxidans D3-2, which posseses the highest copper bioleaching activity, is more resistant to sulfite than other A. ferrooxidans strains, including ATCC 23270. When sulfite oxidase was purified homogeneously from strain D3-2, the oxidized and reduced forms of the purified sulfite oxidase absorption spectra corresponded to those of A. ferrooxidans aa3-type cytochrome c oxidase. The confirmed molecular weights of the α-subunit (52.5 kDa), the β-subunit (25 kDa), and the γ-subunit (20 kDa) of the purified sulfite oxidase and the N-terminal amino acid sequences of the γ-subunit of sulfite oxidase (AAKKG) corresponded to those of A. ferrooxidans ATCC 23270 cytochrome c oxidase. The sulfite oxidase activities of the iron- and sulfur-grown A. ferrooxidans D3-2 were much higher than those cytochrome c oxidases purified from A. ferrooxidans strains ATCC 23270, MON-1 and AP19-3. The activities of sulfite oxidase purified from iron- and sulfur-grown strain D3-2 were completely inhibited by an antibody raised against a purified A. ferrooxidans MON-1 aa3-type cytochrome c oxidase. This is the first report to indicate that aa3-type cytochrome c oxidase catalyzed sulfite oxidation in A. ferrooxidans.
    Download PDF (220K)
  • Saaimatul HUQ, Keigo SUEOKA, Shoichi NARUMI, Fumio ARISAKA, Hitoshi NA ...
    2010 Volume 74 Issue 11 Pages 2273-2280
    Published: November 23, 2010
    Released: November 23, 2010
    [Advance publication] Released: November 07, 2010
    JOURNALS FREE ACCESS
    Unlike Escherichia coli, cyanobacteria generally contain two GroEL homologs. The chaperone function of cyanobacterial GroELs was examined in vitro for the first time with GroEL1 and GroEL2 of Synechococcus elongatus PCC 7942. Both GroELs prevented aggregation of heat-denatured proteins. The ATPase activity of GroEL1 was approximately one-sixth that of Escherichia coli GroEL, while that of GroEL2 was insignificant. The activities of both GroELs were enhanced by GroES, while that of Escherichia coli GroEL was suppressed. The ATPase activity of GroEL1 was greatly enhanced in the presence of GroEL2, but the folding activities of GroEL1 and GroEL2 were much lower than that of Escherichia coli GroEL, regardless of the co-presence of the counterpart or GroES. Both native and recombinant GroEL1 forms a tetradecamer like Escherichia coli GroEL, while GroEL2 forms a heptamer or dimer, but the GroEL1 and GroEL2 oligomers were extremely unstable. In sum, we concluded that the cyanobacterial GroELs are mutually distinct and different from Escherichia coli GroEL.
    Download PDF (275K)
Microbiology & Fermentation Technology Notes
Environmental Science Regular Papers
  • Atiqur RAHMAN, Irnayuli R. SITEPU, Sui-Yan TANG, Yasuyuki HASHIDOKO
    2010 Volume 74 Issue 11 Pages 2202-2208
    Published: November 23, 2010
    Released: November 23, 2010
    [Advance publication] Released: November 07, 2010
    JOURNALS FREE ACCESS
    Supplementary material
    Rhizobacteria isolated from wild dipterocarp saplings in Central Kalimantan, Indonesia, were subjected to Salkowski’s reagent test, which is often used in detecting indolic substances. Among 69 isolates grown in a low-nitrogen medium supplemented with L-tryptophan (TRP), culture fluids of 29 strains were positive to the test, in which 17 bacteria turned red and other 10 pink. All the red type rhizobacteria actively converted TRP into tryptophol (TOL), while some yielded indole-3-acetic acid (IAA) with TOL production. They also showed a capacity to decompose gallotannin into pyrogallol via gallic acid. On the other hand, an active IAA-producing Serratia sp. CK67, and three Fe-solubilizing Burkholderia spp. CK28, CK43, and Citrobacter sp. CK42, were all involved in pink type rhizobacteria, which were more effective, oxidative TRP-degraders than the red type rhizobacteria. Thus, Salkowski’s reagent test should be a useful primary index in the screening of functional rhizobacteria in peatland ecosystem.
    Download PDF (236K)
  • Kyung Hwan BOO, Doseung LEE, Gyeong Lyong JEON, Seung Hee KO, Somi K. ...
    2010 Volume 74 Issue 11 Pages 2226-2231
    Published: November 23, 2010
    Released: November 23, 2010
    [Advance publication] Released: November 07, 2010
    JOURNALS FREE ACCESS
    There is increasing interest in phytoecdysteroids (PEs) because of their potential role in plant defense against insects. To understand the mechanism regulating their levels in plants, the fluctuation, distribution, and biosynthesis of PE 20-hydroxyecdysone (20E) examined in Achyranthes japonica. The total amount of 20E per individual plant initially remained at a constant level, and increased markedly after the first leaf pair (LP) stage, while the concentration of 20E in a given plant decreased rapidly during vegetative growth. In addition, the incorporation of [2-14C]-mevalonic acid into 20E did not differ significantly depending on plant organs and developmental stages, suggesting that biosynthesis of 20E is not restricted to particular organs or growth stages.
    Download PDF (234K)
feedback
Top