Takashi Takagi

Tohoku University, Sendai, Kagoshima, Japan

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Publications (61)179.06 Total impact

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    ABSTRACT: We previously reported the generation of lipopolysaccharide (LPS)-binding peptides by phage display and chemical modification. Among them, a dodecapeptide designated Li5-025 (K′YSSSISSIRAC′; K′ and C′ denote D-lysine and D-cysteine, respectively) showed a high binding affinity for LPS and was resistant to protease digestion (Suzuki et al., 2010). In the current study, Li5-025-bound silica beads, hereafter referred to as P-beads, were generated and found to be devoid of LPS-neutralizing activity. Thus, LPS bound to the P-beads could be directly used in the Limulus amebocyte lysate (LAL) assay. P-beads bound LPS dissolved in solutions of ethanol, pH 4, pH 10, and 0.5 M NaCl and LPS bound to the P-beads was quantitatively assayed. The sensitivity of this assay was observed to be approximately 0.1 pg/mL LPS. P-beads bound LPS dissolved in antithrombin III (AT III) solution which is a strong inhibitor of activated factor C and B as well as the clotting enzyme in the LAL assay; the inhibitory effect of AT III was completely reversed upon washing the P-beads with 25% acetonitrile. This was employed as the first step for the detection of free LPS in plasma using the LAL assay. LPS added to human plasma at 0 °C followed by application to the P-beads and subsequent washing with 25% acetonitrile resulted in low LPS activity as detected by the LAL assay. However, further washing of the P-beads with 0.1% Triton X100 in 25% acetonitrile resulted high LPS activity. This is the first instance of quantitative detection of free LPS in plasma using the LAL assay, the sensitivity of this method was observed to be 1 pg/mL of LPS. The proteins eluted in the 0.1% Triton X-100 wash were analyzed using sodium dodecyl sulfate polyacrylamide gel electrophoresis. Two protein bands of 28 kDa and 18 kDa were predominantly observed. Mass spectrometry analysis revealed that the 28 kDa and 18 kDa bands corresponded to apolipoprotein A-I (apoA-I) and apolipoprotein A-II (apoA-II), respectively. ApoA-I and A-II are components of high density lipoprotein (HDL). Thus, it is likely that the P-beads-bound LPS were sequestered by HDL, resulting in neutralization of its toxicity. By this study showed using P-beads, free LPS in plasma can be quantitatively measured by the LAL assay at a consideration of 1 pg/ mL.
    No preview · Article · May 2014 · Journal of microbiological methods
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    ABSTRACT: Lipopolysaccharide (LPS), a major constituent of the outer membrane of Gram-negative bacteria, is highly toxic and can cause sepsis or septic shock. Therefore, detection of LPS and the ability to neutralize its toxicity is important. We previously obtained a strong LPS-binding peptide, Li5-001, using the phage display method (Matsumoto et al., 2010. J. Microbiol. Methods. 82, 54-58). We modified the sequence the amino acid sequence of this peptide (KNYSSSISSIHAC), by replacing and deleting amino acids to obtain higher LPS-binding affinity and greater resistance to protease digestion. Consequently we obtained a dodecapeptide, Li5-025 (K'YSSSISSIRAC', K' and C' are D-forms of K and C, respectively) which showed a high affinity for LPS, approximately 1000 folds higher affinity than Li5-001 and Kd value of 0.01 nM. By replacing both N- and C-terminal amino acids from L-type to D-type, the peptide was rendered resistant to protease digestion without altering its overall binding capacity.
    Full-text · Article · Nov 2010 · Journal of microbiological methods
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    Full-text · Article · Oct 2010 · Journal of Microbiological Methods
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    ABSTRACT: Lipopolysaccharide (LPS) is a major component of the outer membrane of Gram-negative bacteria. It has strong toxicity and might cause sepsis or septic shock. Thus early detection of LPS and neutralization of LPS toxicity are required. We obtained several new LPS-binding peptides using a phage display method. We synthesized 3 of these peptides and analyzed their binding affinity and capacity to LPS. One of these peptides, named Li5-001, showed high binding affinity to LPS and lipid A; the K(d) values were 10 and 1 nM, respectively. Li5-001 showed a high binding capacity to LPS, and was estimated to bind 130 ng LPS/mg, which is higher than that of polymyxin B (80 ng LPS/mg); however, its LPS-neutralizing activity was low. Li5-001 coupled with beads will be useful for eliminating endotoxin contamination from pharmaceuticals. Its low LPS-neutralizing activity allows to be used in the Limulus amebocyte lysate test without eluting LPS from the Li5-001 coupled beads.
    Full-text · Article · Jul 2010 · Journal of microbiological methods
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    ABSTRACT: A full-length cDNA coding a calmodulin (CaM)-dependent protein kinase gene was cloned from Physarum plasmodia poly(A)-RNA by polymerase chain reaction with the oligonucleotide primers that were designed after the amino acid sequence of highly conserved regions of myosin light-chain kinase. Sequence analysis of the cDNA revealed that this Physarum kinase was a 42,519-Da protein with an ATP-binding domain, Ser/Thr kinase active site signature, and CaM-binding domain. Expression of the cDNA in Escherichia coli demonstrated that the Physarum kinase in the presence of Ca2+ and CaM phosphorylated the recombinant phosphorylatable light chain (PLc) of Physarum myosin II. The peptide analysis after proteolysis of the phosphorylated PLc indicated that Ser 18 was phosphorylated. The site was confirmed by the failure of phosphorylation of PLc, the Ser 18 of which was replaced by Ala. The physiological role of the kinase will be discussed with special reference to the 55-kDa kinase, which had been previously purified from Physarum plasmodia for phosphorylated PLc.
    Full-text · Article · Apr 2005 · Biochemical and Biophysical Research Communications
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    ABSTRACT: Gastropod mollusc myoglobins provide interesting clues to the evolution of this family of proteins. In addition to conventional monomeric myoglobins, this group also has dimeric and unusual indoleamine dioxygenase-like myoglobins. We isolated myoglobin from the radular muscle of living gastropod mollusc Theliostyla albicilla. The myoglobin appeared to be present in an oxidized met-form, a physiologically inactive form that is not capable of binding oxygen. Under the same extraction conditions, myoglobins mainly of the physiologically active oxy-form have been isolated from other molluscs. The complete amino acid sequence of 157 residues of Theliostyla myoglobin shows that it has a long N-terminal extension of seven residues and contains three functional key residues: CD1-Phe, E7-His, and F8-His. The metmyoglobin can easily be reduced to a ferrous state with Na(2)S(2)O(4). The autoxidation rate of the oxy-form was comparable to other molluscan myoglobins over a wide pH range, and Theliostyla myoglobin was shown to be stable as an oxygen-binding protein. Thus, the predominantly met-form of myoglobin in Theliostyla can be attributed to the incomplete functioning of the myoglobin reduction system in the radular muscle. Although the function of Theliostyla myoglobin is unclear, it may be a scavenger of H(2)O(2).
    No preview · Article · Aug 2003 · The International Journal of Biochemistry & Cell Biology
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    ABSTRACT: The organization of troponin I (Tnl) genes from the ascidian Halocynthia roretzi have been determined. Halocynthia possesses roughly two types of TnI isoforms. One type is a single-copied adult TnI (adTnI) gene, which contains eight exons and seven introns. adTnl expresses two isoforms, the shorter body wall muscle TnI and the longer cardiac Tnl, through alternative splicing. The mRNAs of these TnI isoforms may undergo transplicing of the 5‘-leader sequences, like the TnI mRNA of another ascidian species, Ciona intestinalis. The other type comprises multi-copied larval Tnl (laTnI) genes. Halocynthia has at least three laTnIs (α,β and γ), which are composed of five exons and four introns, and two of them (α and γ) are clustered in tandem. All laTnls have B- and M-regions within their 5'-upstream regions, which have been discovered to be the regulatory elements of Halocynthia larval actin genes. The expression of Halocynthia laTnIs and larval actins may be regulated in the same manner. It is known that Ciona does not possess a larva-specific TnI isoform. The phylogenetic tree of ascidian Tnls suggests that laTnls might have only been generated within the Pleurogona lineage after Enterogona/Pleurogona divergence, and this scenario well agress with the absence of laTnIs in Ciona
    No preview · Article · Aug 2002 · Journal of Biochemistry
  • Hajime Julie Yuasa · Takashi Takagi
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    ABSTRACT: Troponin C (TnC) superfamily genes essentially possess five introns, the positions of all but the fourth being highly conserved. The fourth intron is frequently absent from protostomian invertebrate genes, such as calmodulin or TnC. We previously proposed that the common ancestor of TnC superfamily genes never possessed an intron corresponding to today's fourth introns, and that members of the superfamily independently gained a fourth intron in the evolutionary pathway of each lineage. In the present study, we isolated the TnC cDNA from the sandworm, Perinereisvancauricatetradentata and determined its genomic structure. Sandworm TnC appears to exist as a single copy gene consisting of six exons and five introns. The positions of the first, second, third and fifth introns are identical to other TnCs, but that of the fourth intron is unique. This is in good agreement with the above-mentioned scheme, i.e. the gain of the fourth intron of sandworm TnC might have occurred within the annelid lineage after annelida/mollusca divergence.
    No preview · Article · May 2001 · Gene
  • Tsuyoshi Morita · Kenji Saitoh · Takashi Takagi · Yasuo Maeda
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    ABSTRACT: Upon deprivation of nutrients, Dictyostelium discoideum Ax-2 cells arrest proliferation and initiate a metamorphosed developmental program including induction of altered gene expressions which are necessary for differentiation. In Ax-2 cells, we found out a member of Hsp90 family usually contained in the endoplasmic reticulum (ER), Dd-GRP94 (Dictyostelium discoideum glucose-regulated protein 94). In general, GRP94 are induced either by glucose-depletion or by depletion of Ca2+ in intracellular Ca2+ stores. Unexpectedly, however, the expression of Dd-grp94 was greatly reduced within 60 min of starvation. Dd-grp94-overexpressing cells (GRP94OE cells) collected without forming distinct aggregation streams, and never formed normal fruiting bodies. Also, prespore differentiation as well as maturation into spores and stalk cells were particularly impaired in the GRP94OE cells. Thus Dd-GRP94 seems to be crucial in late differentiation as well as in starvation response.
    No preview · Article · Sep 2000 · Biochemical and Biophysical Research Communications
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    ABSTRACT: Calcium binding protein 40 (CBP40) is a Ca(2+)-binding protein abundant in the plasmodia of Physarum polycephalum. CBP40 consists four EF-hand domains in the COOH-terminal half and a putative alpha-helix domain in the NH(2)-terminal half. We expressed recombinant proteins of CBP40 in Escherichia coli to investigate its Ca(2+)-binding properties. Recombinant proteins of CBP40 bound 4 mol of Ca(2+) with much higher affinity (pCa(1/2) = 6.5) than that of calmodulin. When residues 1-196 of the alpha-helix domain were deleted, the affinity for Ca(2+) decreased to pCa(1/2) = 4.6. A chimeric calmodulin was generated by conjugating the alpha-helix domain of CBP40 with calmodulin. The affinity of Ca(2+) for the chimeric calmodulin was higher than that for calmodulin, suggesting that the alpha-helix domain is responsible for the high affinity of CBP40 for Ca(2+). CBP40 forms large aggregates reversibly in a Ca(2+)-dependent manner. A mutant protein with a deletion of NH(2)-terminal 32 residues, however, could not aggregate, indicating the importance of these residues for the aggregation. The aggregation occurs above micromolar levels of Ca(2+) concentration, so it may only occur when CBP40 is secreted out of the plasmodial cells.
    Preview · Article · May 2000 · Biochemistry
  • Hajime Julie Yuasa · Takashi Takagi
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    ABSTRACT: Two cDNAs encoding troponin C (TnC) isoforms are isolated from the scallop, Patinopecten yessoensis, striated adductor muscle. The sequential differences between these isoforms, named TnC(long) and TnC(short), are restricted in several residues of the C-terminal region. TnC(long) is commonly expressed in both the striated and the smooth adductor muscle; however, TnC(short) is only in the striated adductor muscle. The TnC gene is a single copy gene in the scallop, thus they are expressed through the alternative splicing from the same gene. The scallop TnC gene is constructed from five exons and four introns, and positions of introns are identical with chordate TnC genes, although the scallop TnC possesses no corresponding intron to the fourth intron of chordates. The loss of this intron is also observed in Drosophila TnC; these may be remnants of their ancestor, namely the early metazoan TnC gene might be a five exons-four introns structure. In addition, the absence of the corresponding intron is also observed among protostomian calmodulins (CaMs), a molecule closely related to TnC. This suggests that the common ancestor gene of the TnC superfamily might also be a five exons-four introns structure. Assuming this to be true, the discordance of the fourth intron positions observed among members of the family is well explained by the evolutionary independent gain of the intron on each member's lineage.
    No preview · Article · Apr 2000 · Gene
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    Akiko Maruyama · Kimiharu Ishizawa · Takashi Takagi
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    ABSTRACT: β-Cyanoalanine synthase (CAS; EC 4.4.1.9) and two kinds of cysteine synthases (CS; EC 4.2.99.8) have been purified from the particulate fraction of potato tubers. By DEAE Sephacel and Resource PHE chromatography, CAS activity was separated from two CS activities, designated as CS-1 and CS-2. The molecular masses of CAS, CS-1 and CS-2 were estimated to be 37, 39 and 34 kDa, respectively, by SDS-PAGE analysis. The purified CAS had CS activity, and both CS-1 and CS-2 had CAS activity. However, CAS and CSs had significant differences in kinetic characters. The antibody raised against purified CAS discriminated CAS from CSs, whereas the antibody raised against purified CS-2 recognized CS-1 and CS-2 but not CAS. The molecular mass and the partial amino acid sequence of CS-2 were similar to those of the cytosolic CS of potato, whereas the molecular mass of CS-1 was similar to that of the plastidic CS. The partial amino acid sequence of CAS was similar to those of CS isozymes, especially the mitochondrial CS isolated from spinach.
    Full-text · Article · Mar 2000 · Plant and Cell Physiology
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    ABSTRACT: Drebrin is an actin-binding protein which is expressed at highly levels in neurons. When introduced into fibroblasts, it has been known to bind to F-actin and to cause remodeling of F-actin. Here, we performed a domain analysis of the actin-binding and actin-remodeling activities of drebrin. Various fragments of drebrin cDNA were fused with green fluorescent protein cDNA and introduced into Chinese hamster ovary cells. Association of the fusion protein with F-actin and remodeling of the F-actin were examined. We found that the central 85-amino-acid sequence (residues 233–317) was sufficient for the binding to and remodeling of F-actin. The binding activity of this fragment was relatively low compared with that of full-length drebrin, but all the types of abnormalities of F-actin that are observed with full-length drebrin were also observed with this fragment. When this sequence was further fragmented, the actin-binding activity was greatly reduced and the actin-remodeling activity disappeared. The actin-binding activity of the central region of drebrin was confirmed by a cosedimentation assay of chymotryptic fragments of drebrin with purified actin. These data indicate that the actin-binding domain and actin-remodeling domain are identical and that this domain is located at the central region of drebrin.
    No preview · Article · Jan 2000 · Experimental Cell Research
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    ABSTRACT: The analysis of fibroin secretion-deficient 'naked-pupa' mutant silkworms has suggested that the disulfide linkage between heavy (H) and light (L) chains of fibroin, produced by the silkworm, Bombyx mori, is essential in its efficient large-scale secretion from the posterior silk gland cells. However, the site of disulfide-linkage between H- and L-chains has not been determined. In this study, cysteine residues involved in the single disulfide linkage between H- and L-chains were identified as the twentieth residue from the carboxyl terminus of H-chain (Cys-c20) and Cys-172 of L-chain by sequencing of genomic clones and peptide analysis. Furthermore, Cys-c4 (fourth residue from the carboxyl terminus) and Cys-c1 at the carboxyl terminus of H-chain were shown to form an intramolecular disulfide bond.
    No preview · Article · Jul 1999 · Biochimica et Biophysica Acta
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    ABSTRACT: In addition to its kinase activity, myosin light chain kinase has an actin-binding activity, which results in bundling of actin filaments [Hayakawa et al., Biochem. Biophys. Res. Commun. 199, 786-791, 1994]. There are two actin-binding sites on the kinase: calcium- and calmodulin-sensitive and insensitive sites [Ye et al., J. Biol. Chem. 272, 32182-32189, 1997]. The calcium/calmodulin-sensitive, actin-binding site is located at Asp2-Pro41 and the insensitive site is at Ser138-Met213. The cyanogen bromide fragment, consisting of Asp2-Met213, is furnished with both sites and is the actin-binding core of myosin light chain kinase. Cross-linking between the two sites assembles actin filaments into bundles. Breaking of actin-binding at the calcium/calmodulin-sensitive site by calcium/calmodulin disassembles the bundles.
    Preview · Article · Jun 1999 · Biochimica et Biophysica Acta
  • Hajime Julie Yuasa · Hiroaki Yamamoto · Takashi Takagi
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    ABSTRACT: Two distinct calmodulin (CaM) genes are isolated from the ascidian, Halocynthia roretzi, (Hr-CaM A and Hr-CaM B) and those structures are determined. There are three nucleotide substitutions, producing two amino acid differences between Hr-CaM A and Hr-CaM B, and those are corresponding to two of the known eight variable residues among metazoan CaMs. Both Hr-CaM A and Hr-CaM B are constructed from six exons and five introns, and the positions of introns are identical. The positions of introns of Hr-CaMs are also identical with those of vertebrate CaMs, except third introns. The third introns of Hr-CaMs are inserted at 28bp upstream when compared with vertebrate CaMs. Thus, sliding of the third intron might have occurred in only the ascidian lineage prior to the gene duplication that also occurred only in that lineage. In addition, with the comparison of the intron positions, we attempt to investigate the vicissitude of introns during the evolution of metazoan CaMs.
    No preview · Article · Apr 1999 · Gene
  • Yuan Lin · Hiroko Kishi · Akio Nakamura · Takashi Takagi · Kazuhiro Kohama
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    ABSTRACT: Talin, an actin-binding protein from smooth muscle, is shown to bind to myosin in such a way that it stimulates the ATPase activity of myosin irrespective of the phosphorylation state of myosin. The binding site is shown to be localized at the N-terminal, 47 KDa fragment. The position of the actin-binding site at the C terminal suggests that talin may work as a crosslinker between myosin and actin.
    No preview · Article · Sep 1998 · Biochemical and Biophysical Research Communications
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    ABSTRACT: The activity of rβ-cyanoalanine synthase (CAS, EC 4.4.1.9) in cotyledons of cocklebur seeds ( Xanthium penn-sylvanicum Wallr.) was detected both in the soluble and particulate fractions. The CAS activity of the soluble fraction (cytosolic CAS activity) was 10 times higher than that of the particulate fraction. The CAS activity of the particulate fraction was confirmed to be localized in the mitochondria. Both enzymatic activities were clearly separated by non-denaturing PAGE. The enzyme with cytosolic CAS activity has been extensively purified and separated into three different forms designated as cyt-1, cyt-2, and cyt-3. According to the SDS-PAGE analysis, the three enzymes are estimated to be a homodimer composed of 35-kDa sub-units. The purified enzymes showed CS activity. Partial amino acid sequences of cyt-1 were determined and had a high homology with cysteine synthases (CS, EC 4.2.99.8) from other plant sources. The catalytic action of the purified CSs in converting cyanide and cysteine into H 2 S and rβ-cyanoalanine was confirmed by the detection of significant 14CN incorporation into rβ-cyanoalanine. These results indicated that cytosolic CAS activity is due to cytosolic CS and suggested that the CAS activity of CS is likely to be involved in cyanide metabolism in plant tissues.
    Full-text · Article · Aug 1998 · Plant and Cell Physiology
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    ABSTRACT: Three C-type lectins of 15 kDa were isolated from the water-soluble fraction (WSF) of the body surface mucus of the land slug, Incilaria fruhstorferi. Based on their partial amino acid sequences, the nucleotide sequences of cDNAs encoding these lectins, named incilarin A, B and C, were determined. cDNAs of incilarin A, B and C consisted of 673, 663 and 715 bp, and deduced amino acids were 150, 149 and 156 residues, respectively. All three lectins had signal peptides of 17 amino acid residues at their N-termini. They showed 44-55% amino acid sequence identity with each other, and lower but significant homology with the other animal C-type lectins and antifreeze protein. Incilarin A and B seem to possess two intramolecular disulfide bonds in the carbohydrate-binding domain (CRD) conserved among the animal C-type lectins, however, one of these bonds is absent in incilarin C.
    Full-text · Article · Apr 1998 · Comparative Biochemistry and Physiology Part B Biochemistry and Molecular Biology
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    ABSTRACT: In addition to its kinase activity, the myosin light chain kinase (MLCK) of smooth muscle has an actin binding activity through which it can regulate the actin-myosin interaction of smooth muscle (Kohama, K., Okagaki, T., Hayakawa, K., Lin, Y., Ishikawa, R., Shimmen, T., and Inoue, A. (1992) Biochem. Biophys. Res. Commun. 184, 1204–1211). In this study, we have analyzed the actin binding activity of MLCK and related it to its amino acid sequence by producing native and recombinant fragments of MLCK. Parent MLCK exhibited both calcium ion (Ca2+) and calmodulin (Ca2+/CaM)-sensitive and Ca2+/CaM-insensitive binding to actin filaments. The native fragment, which consists of the Met1–Lys114 sequence (Kanoh, S., Ito, M., Niwa, E., Kawano, Y., and Hartshorne, D. J. (1993)Biochemistry 32, 8902–8907), and the recombinant NN fragment, which contains this 1–114 sequence, showed only Ca2+/CaM-sensitive binding. An inhibitory effect of the NN fragment on the actin-myosin interaction was observed by assayingin vitro motility and by measuring the actin-activated ATPase activity of myosin. The recombinant NN/41 fragment, which is constructed without the Met1–Pro41 sequence of the NN fragment, lost both the actin binding activity and the inhibitory effect. We confirmed the importance of the 1–41 sequence by using a few synthetic peptides to compete against the NN fragment in binding to actin filaments. The experiments using recombinant fragments and synthetic peptides also revealed that the site for CaM-binding is the Pro26–Pro41 sequence. The site for the Ca2+/CaM-insensitive binding, which is shown to be localized between the Ca2+/CaM-sensitive site and the central kinase domain of MLCK, exerted no regulatory effects on the actin-myosin interaction.
    Full-text · Article · Dec 1997 · Journal of Biological Chemistry

Publication Stats

1k Citations
179.06 Total Impact Points

Institutions

  • 1980-2010
    • Tohoku University
      • • Department of Developmental Biology and Neuroscience
      • • Graduate School of Life Sciences
      • • Biological Institute
      • • Department of Biochemistry
      • • Department of Chemistry
      Sendai, Kagoshima, Japan
  • 1993-1994
    • University of Geneva
      • Department of Biochemistry
      Genève, Geneva, Switzerland