Faculty Profiles - SHIMANOUCHI Toshinori

Papers - SHIMANOUCHI Toshinori

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Conformational change of single-stranded RNAs induced by liposome binding

Keishi Suga, Tomoyuki Tanabe, Hibiki Tomita, Toshinori Shimanouchi, Hiroshi Umakoshi

NUCLEIC ACIDS RESEARCH 39 ( 20 ) 8891 - 8900 2011.11

Language：English Publishing type：Research paper (scientific journal) Publisher：OXFORD UNIV PRESS

The interaction between single-stranded RNAs and liposomes was studied using UV, Fourier Transform Infrared spectroscopy (FTIR) and Circular Dichroism spectroscopy (CD). The effect of the surface characteristics of liposomes, which were composed of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) and modified with cholesterol (Ch) or 1,2-dioleoyl-3-trimethylammonium propane (DOTAP), on the liposome-RNA interaction was investigated. The fluorescence of 6-(p-toluidino)naphthalene-2-sulfonate (TNS) embedded in the liposome surface (epsilon = 30-40) was decreased in the presence of tRNA, suggesting that single-stranded tRNA could bind onto the liposome. The dehydration of -PO(2)(-) -, guanine (G) and cytosine (C) of tRNA molecules in the presence of liposomes suggested both an electrostatic interaction (phosphate backbone of tRNA and trimethylammonium group of POPC, DOTAP) and a hydrophobic interaction (guanine or cytosine of tRNA and aliphatic tail of lipid). The tRNA conformation on the liposome was determined by CD spectroscopy. POPC/Ch (70/30) maintained tRNA conformation without any denaturation, while POPC/DOTAP(70/30) drastically denatured it. The mRNA translation was evaluated in an Escherichia coli cell-free translation system. POPC/Ch(70/30) enhanced expression of green fluorescent protein (GFP) (116%) while POPC/DOTAP(70/30) inhibited (37%), suggesting that the conformation of RNAs was closely related to the translation efficiency. Therefore, single-stranded RNAs could bind to liposomal membranes through electrostatic and hydrophobic attraction, after which conformational changes were induced depending on the liposome characteristics.

DOI： 10.1093/nar/gkr568

Sensitivity Enhancement of Leakage Current Microsensor for Detection of Target Protein by Using Protein Denaturant

Minoru Noda, Prinya Lorchirachoonkul, Toshinori Shimanouchi, Kaoru Yamashita, Hiroshi Umakoshi, Ryouichi Kuboi

IEEE SENSORS JOURNAL 11 ( 11 ) 2749 - 2755 2011.11

Language：English Publishing type：Research paper (scientific journal) Publisher：IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC

We have developed a highly-sensitive leakage current microsensor by using 1,2-dipalmitoyl-sn-glycero-3-phosphocholline (DPPC) liposome entrapping K-4[Fe(CN)(6)] solution to detect the existence of proteins. In this work, the addition of guanidinium hydrochloride (GuHCl) as protein denaturant successfully resulted in a prominent improvement in sensitivity by 129-folds of magnitude. This is because the modulation of conformation of the target proteins, carbonic anhydrase from bovine (CAB) and lysozyme could contribute to the promotion of the interaction between the liposome and the target protein.

DOI： 10.1109/JSEN.2011.2159109

Span 80 vesicles have a more fluid, flexible and "wet" surface than phospholipid liposomes

Keita Hayashi, Toshinori Shimanouchi, Keiichi Kato, Tatsuhiko Miyazaki, Atsushi Nakamura, Hiroshi Umakoshi

COLLOIDS AND SURFACES B-BIOINTERFACES 87 ( 1 ) 28 - 35 2011.10

Language：English Publishing type：Research paper (scientific journal) Publisher：ELSEVIER SCIENCE BV

The surface properties of Span 80 vesicles at various cholesterol contents, together with those of various liposomes, were characterized by using fluorescence probes. The membrane fluidity of the Span 80 vesicles was measured by 1,6-dipheny1-1.3.5-hexatriene (DPH) and trimethlyammonium-DPH (TMA-DPH), and the results suggested that the surface of the Span 80 vesicles was fluid due to the lateral diffusion of Span 80 molecules. The depolarization measured by TMA-DPH and the headgroup mobility measured by dielectric dispersion analysis indicated the high mobility of the head group of Span 80 vesicles. This suggested that the surface of Span 80 vesicles was flexible due to the head group structure of Span 80, sorbitol. In addition, spectrophotometric analysis with 6-dodecanoyl-N, N-dimethy1-2-naphthylamine and 8-anilino-1-naphthalenesulfonic acid indicated that the water molecules could easily invade into the interior of the Span 80 vesicle membrane, suggesting that the membrane surface was more wet than the liposome surface. These surface properties indicated that the protein could interact with the interior of vesicle membranes, which was similar to the case of cholesterol. Thus the present results confirmed that the Span 80 vesicle surfaces showed the unique characteristics of fluidity, flexibility, and "wetness", whereas the liposome surfaces did not. (C) 2011 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.colsurfb.2011.04.029

Span 80 vesicles have a morefluid, flexibleand"wet"surface than phospholipid liposomes. Reviewed

Hayashi Keita, Shimanouchi Toshinori, Kato Keiichi, Miyazaki Tatsuhiko, Nakamura Atsushi, Umakoshi Hiroshi

Colloids and surfaces. B, Biointerfaces 87 ( 1 ) 28 2011.10

Language：English Publishing type：Research paper (scientific journal)

The surface properties of Span 80 vesicles at various cholesterol contents, together with those of various liposomes, were characterized by using fluorescence probes. The membrane fluidity of the Span 80 vesicles was measured by 1,6-diphenyl-1.3.5-hexatriene (DPH) and trimethlyammonium-DPH (TMA-DPH), and theresults suggested that the surface of the Span 80 vesicles was fluid due to the lateral diffusion of Span 80 molecules. The depolarization measured by TMA-DPH and the headgroup mobility measured by dielectric dispersion analysis indicated the high mobility of the head group of Span 80 vesicles. This suggested that the surface of Span 80 vesicles was flexible due to the head group structure of Span 80, sorbitol. In addition, spectrophotometric analysis with 6-dodecanoyl-N, N-dimethyl-2-naphthylamine and 8-anilino-1-naphthalenesulfonic acid indicated that the water molecules could easily invade into the interior of the Span 80 vesicle membrane, suggesting that the membrane surface was more wet than the liposome surface. These surface propertiesindicated that the protein could interact with the interior of vesicle membranes, which was similar to the case of cholesterol. Thus the pr

DOI： 10.1016/j.colsurfb.2011.04.029

Oxidative Stress Can Affect the Gene Silencing Effect of DOTAP Liposome in an In Vitro Translation System

Hiroshi Umakoshi, Tomoyuki Tanabe, Keishi Suga, Huong Thi Bui, Toshinori Shimanouchi, Ryoichi Kuboi

INTERNATIONAL JOURNAL OF BIOLOGICAL SCIENCES 7 ( 3 ) 253 - 260 2011

Language：English Publishing type：Research paper (scientific journal) Publisher：IVYSPRING INT PUBL

Oxidative stress can affect in vitro GFP expression through its control of the gene silencing effect of the liposome prepared by 1,2- dioleoyl-3-trimethyl-ammonium propane ( DOTAP). The gene silencing effect of cationic DOTAP liposome in in vitro GFP expression, especially focusing on its translation process, and the effects of oxidative stress on its silencing effect were investigated. GFP expression, initiated by mRNA, was found to be thoroughly inhibited in the presence of DOTAP liposome at concentration of more than 2.5 mM, though its inhibitory effect was reduced in the presence of hydrogen peroxide. The analyses of (i) the interaction of mRNA with DOTAP, (ii) the chemical structure of DOTAP, and (iii) the membrane fluidity of DOTAP liposome imply the possible role of gene expression by the liposome membrane and stress conditions.

DOI： 10.7150/ijbs.7.253

Development of LIPOzymes Based on Biomembrane Process Chemistry

Hiroshi Umakoshi, Toshinori Shimanouchi, Ryoichi Kuboi

Pharmaceutical Process Chemistry 421 - 441 2010.10

Cationic liposome can interfere mRNA translation in an E. coli cell-free translation system

Huong Thi Bui, Hiroshi Umakoshi, Keishi Suga, Tomoyuki Tanabe, Kien Xuan Ngo, Toshinori Shimanouchi, Ryoichi Kuboi

BIOCHEMICAL ENGINEERING JOURNAL 52 ( 1 ) 38 - 43 2010.10

Language：English Publishing type：Research paper (scientific journal) Publisher：ELSEVIER SCIENCE BV

The effect of cationic liposome prepared from 1,2-dioleoyl-3-trimethyl- ammonium-propane (DOTAP) on the gene expression at the mRNA translation level was investigated using an E. coli cell-free translation system. DOTAP liposome at 3 mM inhibited the mRNA translation of green fluorescent protein (GFP), as indicated both by the fluorescence intensity of GFP and by SDS-PAGE analysis. The role of DOTAP liposome on the inhibition of mRNA translation was revealed that the cationic quaternary amine groups on the liposome surface can interact and neutralize the anionic phosphate groups on mRNA by an electrostatic interaction. mRNA molecules still existed without any degradation in the presence of DOTAP liposome although it could not be translated. These results clearly illustrated that the DOTAP liposome could knock down mRNA and silence its activity of translation in an E. coli cell-free system. (C) 2010 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.bej.2010.07.001

Catechol derivatives inhibit the fibril formation of amyloid-beta peptides

Vu Thi Huong, Toshinori Shimanouchi, Naoya Shimauchi, Hisashi Yagi, Hiroshi Umakoshi, Yuji Goto, Ryoichi Kuboi

JOURNAL OF BIOSCIENCE AND BIOENGINEERING 109 ( 6 ) 629 - 634 2010.6

Language：English Publishing type：Research paper (scientific journal) Publisher：SOC BIOSCIENCE BIOENGINEERING JAPAN

The inhibition of fibril formation of amyloid beta proteins (A beta) would be attractive therapeutic targets for the treatment of Alzheimer's disease (AD). Dopamine (DA) and other catechol derivatives were used as inhibitory factors for A beta fibril formation. The fibril formation of A beta was monitored by Thioflavin T fluorescence, a transmission electron microscopy (TEM) and a total internal reflection fluorescence microscopy (TIRFM). Catechol and its derivatives showed the dose-dependent inhibitory effects on the spontaneous A beta fibril formation. The inhibitory activity depended on the chemical structure of catechol derivatives both in the presence and absence of the liposome a model of biomembrane. Formation of catechol quinone-conjugated-A beta adduct by a Schiff-base is a key step for the inhibition effect of A beta fibril formation. (C) 2009, The Society for Biotechnology, japan. All rights reserved.

DOI： 10.1016/j.jbiosc.2009.11.010

Laser-induced Propagation and Destruction of Amyloid beta Fibrils

Hisashi Yagi, Daisaku Ozawa, Kazumasa Sakurai, Toru Kawakami, Hiroki Kuyama, Osamu Nishimura, Toshinori Shimanouchi, Ryoichi Kuboi, Hironobu Naiki, Yuji Goto

JOURNAL OF BIOLOGICAL CHEMISTRY 285 ( 25 ) 19660 - 19667 2010.6

Language：English Publishing type：Research paper (scientific journal) Publisher：AMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC

The amyloid deposition of amyloid beta (A beta) peptides is a critical pathological event in Alzheimer disease (AD). Preventing the formation of amyloid deposits and removing preformed fibrils in tissues are important therapeutic strategies against AD. Previously, we reported the destruction of amyloid fibrils of beta 2-microglobulin K3 fragments by laser irradiation coupled with the binding of amyloid-specific thioflavin T. Here, we studied the effects of a laser beam on A beta fibrils. As was the case for K3 fibrils, extensive irradiation destroyed the preformed A beta fibrils. However, irradiation during spontaneous fibril formation resulted in only the partial destruction of growing fibrils and a subsequent explosive propagation of fibrils. The explosive propagation was caused by an increase in the number of active ends due to breakage. The results not only reveal a case of fragmentation-induced propagation of fibrils but also provide insights into therapeutic strategies for AD.

DOI： 10.1074/jbc.M109.076505

Development of liposome-based mimics of superoxide dismutase and peroxidase based on the "LIPOzyme" concept

Hiroshi Umakoshi, Kengo Morimoto, Naoto Yasuda, Toshinori Shimanouchi, Ryoichi Kuboi

JOURNAL OF BIOTECHNOLOGY 147 ( 1 ) 59 - 63 2010.5

Language：English Publishing type：Research paper (scientific journal) Publisher：ELSEVIER

An antioxidative liposome catalyst. LIPOzyme, that mimics both superoxide dismutase (SOD) and peroxidase (POD)-like activities has been developed by using liposomes modified with simple ligands (dodecanoyl-histidine, Dodec-His) and metal ions (Mn) The SOD-like activity is dependent on the stability of the ligand-metal complex on the liposome membrane, with the value being higher for the DPPC liposome and at a higher pH The POD-like activity was found to be maximal in the case of DMPC liposome, in which the ligand-metal complex is inserted more deeply into the membrane. It was thus shown that liposome modified with simple ligands can exhibit different enzyme-like activities depending on the characteristics of the liposome membrane. (C) 2010 Elsevier B V All rights reserved.

DOI： 10.1016/j.jbiotec.2010.02.013

Analysis of the 22-NBD-cholesterol transfer between liposome membranes and its relation to the intermembrane exchange of 25-hydroxycholesterol

Haruyuki Ishii, Toshinori Shimanouchi, Hiroshi Umakoshi, Peter Walde, Ryoichi Kuboi

COLLOIDS AND SURFACES B-BIOINTERFACES 77 ( 1 ) 117 - 121 2010.5

Language：English Publishing type：Research paper (scientific journal) Publisher：ELSEVIER SCIENCE BV

The transfer of 22-NBD-cholesterol (22-(N-(7-Nitrobenz-2-oxa-1,3-diazol-4-yl)amino)-23,24-bisnor-5-cholen-3-ol) between two liposome membranes was quantitatively analyzed by using the fluorescence resonance energy transfer (FRET) method. Liposomes labeled with both 22-NBD-cholesterol and a rhodamine-labeled phosphatidylethanolamine (Rh-DHPE) were used as donor liposomes, and the 22-NBD-cholesterol transfer from these donor liposomes to acceptor liposomes prepared from same type of phosphatidylcholine was monitored. The transfer kinetics was found to be composed of a fast and a slow phase, and all kinetic measurements could be fitted with a bi-exponential model. The results obtained indicate that the 22-NBD-cholesterol transfer kinetics between liposome membranes depends on the fluidity of the liposome used and that the curvature may affect the kinetics. Furthermore, the behavior of 22-NBD-cholesterol in lipid membrane is similar to that of the oxysterol 25-hydroxycholesterol rather than cholesterol. It is proposed that 22-NBD-cholesterol can be a useful fluorescent probe to mimic the intermembrane transfer of oxidized cholesterols like 25-hydroxycholesterol, rather than that of cholesterol itself. (C) 2010 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.colsurfb.2010.01.002

Preparation of superoxide dismutase LIPOzyme in hollow fiber membrane module

Hiroyuki Sugaya, Hiroshi Umakoshi, K. B. M. A. Fadzil, Le Quoc Tuan, Toshinori Shimanouchi, Ryoichi Kuboi

DESALINATION AND WATER TREATMENT 17 ( 1-3 ) 281 - 287 2010.5

Language：English Publishing type：Research paper (scientific journal) Publisher：DESALINATION PUBL

Liposome-loaded membrane module (LLM) was prepared in hollow fiber module (HF-LLM), where the liposome was loaded into the hollow fiber membrane. The filtration property of the LLM was characterized. The oxidized and fragmented superoxide dismutase (SOD) was applied to the prepared LLM to separate the peptide to give a SOD-like activity on the liposome membrane, resulting in the recovery of the specific peptide. It was found that the SOD-like activity could be obtained in the SOD LIPOzyme prepared, resulting in the effective elimination of the superoxide in the HF-LLM.

DOI： 10.5004/dwt.2010.1730

Monitoring of membrane damages by dialysis treatment: Study with membrane chip analysis

Toshinori Shimanouchi, Ena Oyama, Huong Thi Vu, Haruyuki Ishii, Hiroshi Umakoshi, Ryoichi Kuboi

DESALINATION AND WATER TREATMENT 17 ( 1-3 ) 45 - 51 2010.5

Language：English Publishing type：Research paper (scientific journal) Publisher：DESALINATION PUBL

The liposome immobilized on indium tin-oxide electrode was prepared as a "Membrane Chip'' to evaluate the liposome-liposome interaction. Three kinds of neutral liposomes entrapping the fluorescence probe, calcein, were utilized as a sensory liposome. Twenty four kinds of liposomes were used to construct a membrane library based on the calcein release behavior. The loading of liposome including the unsaturated phospholipid into the dialyzer induced the variation of surface state of liposome membrane. We analyzed the above liposome by a comparison of it with the membrane library constructed by Membrane Chip. The liposome after its dialysis treatment was found to show the membrane property of the liposome with domain-like structure prior to the interaction with amyloid beta protein. Also the above liposome showed the oxidized liposome-like membrane property. In conclusion, we demonstrated a membrane library-based method to evaluate the surface state of the model biomembranes with unclear surface property.

DOI： 10.5004/dwt.2010.1697

Liposomes destabilize tRNA during heat stress

Keishi Suga, Hiroshi Umakoshi, Hibiki Tomita, Tomoyuki Tanabe, Toshinori Shimanouchi, Ryoichi Kuboi

BIOTECHNOLOGY JOURNAL 5 ( 5 ) 526 - 529 2010.5

Language：English Publishing type：Research paper (scientific journal) Publisher：WILEY-V C H VERLAG GMBH

Biomembranes play an important role in cellular response to heat stress. In this study, we focus on the interaction between liposomes and tRNA. Upon heat treatment we determined circular dichroism spectra of tRNA in presence of liposomes prepared from POPC (1-palmitoyl-2-oleoylsn-glycero-3-phosphocholine) and cholesterol (Ch). To compare thermal stability, midpoint temperature (T(m)) of tRNA was calculated from normalized theta(208). Addition of POPC/Ch liposomes decreased the T(m) value of tRNA from 48 degrees C to 38 degrees C. We conclude that POPC/Ch liposomes interact with tRNA and destabilize its conformation under heat stress.

DOI： 10.1002/biot.200900289

A sensitive thermochemical detector with a new target droplet supply and immobilization process

M. Noda, T. Shimanouchi, T. Asai, K. Yamashita, M. Okuyama, H. Umakoshi, R. Kuboi

SENSORS AND ACTUATORS B-CHEMICAL 147 ( 1 ) 337 - 342 2010.5

Language：English Publishing type：Research paper (scientific journal) Publisher：ELSEVIER SCIENCE SA

A thermal detector structure of bio-thermochemical sensor with a new target droplet supply is considered, analyzed and developed. The basic structure of the bio-thermochemical sensor is a Pt film microbolometer thermally insulated from a silicon thermal conductor substrate to enhance the temperature sensitivity. In the detector structure, it is calculated from a finite element analysis that the variation in lateral size of immobilized droplet, larger than detector film size of 50 mu m, affects little on the temperature change, while the real vertical size of the droplet keeps nearly the same as around 70 mu m. These indicate the validity of formation of the target droplet onto the detector part as an accurate thermal measurement. Based on this, a new supplying and immobilizing process of the droplet is developed to realize a soft formation of the droplet on the detector surface with retained intact immobilization of liposome at least for 24 h, not giving the membrane a mechanical stress and destruction.
Thereafter, we have evaluated a bio-thermochemical reaction in a droplet of mixed solution of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) liposome and lysozyme by the newly developed thermochemical sensor. Some new peaks in thermal spectra were observed for the case of the mixture, which were not found so far in the case of each single solution of liposome or lysozyme, indicating that their bio-thermochemical interactions were newly detected in this method. It was also found that the thermal sensor with new forming process of droplet target detects the thermochemical reaction of respective DPPC liposome and lysozyme, consistent with the same as those reported by a differential scanning calorimetry. (C) 2010 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.snb.2010.03.012

Chitosanase displayed on liposome can increase its activity and stability

Kien Xuan Ngo, Hiroshi Umakoshi, Toshinori Shimanouchi, Hiroyuki Sugaya, Ryoichi Kuboi

JOURNAL OF BIOTECHNOLOGY 146 ( 3 ) 105 - 113 2010.4

Language：English Publishing type：Research paper (scientific journal) Publisher：ELSEVIER SCIENCE BV

The strategy to prepare a novel biocatalyst by the immobilization of chitosanase onto liposome (ICL) was carried out based on the direct interaction of liposomes with cell membrane of Streptomyces griseus cell. The ICL was characterized in relation to the molecular weight of protein, the chitosanase activity, the effect of the surface hydration of various liposomes on hydrolysis activity of immobilized chitosanase and the stability of ICL under various extreme conditions. The SOS-PAGE analysis of the purified ICL sample shows the existence of a protein with approximately 39 kDa that corresponded to the sum of weight of the mature chitosanase and its signal peptide (38.8 kDa). The above protein of ICL also expresses the chitosanase activity that is significantly higher than that of the conventional chitosanase. Furthermore, the surface hydration of liposomes used to prepare ICL that affected the activity of immobilized chitosanase verified the importance of liposome surfaces. Indeed, the stability of ICL assayed by measuring the chitosanase activity is significantly higher than that of conventional chitosanase under various temperatures and pH conditions. These characteristics of ICL show the possible preparation of the biocatalysts that can be prepared by immobilizing enzymes onto liposome vesicles properly. (C) 2010 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.jbiotec.2010.01.014

A beta/Cu-catalyzed oxidation of cholesterol in 1,2-dipalmitoyl phosphatidylcholine liposome membrane

Toshinori Shimanouchi, Makoto Tasaki, Huong Thi Vu, Haruyuki Ishii, Noriko Yoshimoto, Hiroshi Umakoshi, Ryoichi Kuboi

JOURNAL OF BIOSCIENCE AND BIOENGINEERING 109 ( 2 ) 145 - 148 2010.2

Language：English Publishing type：Research paper (scientific journal) Publisher：SOC BIOSCIENCE BIOENGINEERING JAPAN

The amyloid beta protein with 42 amino acid residues (A beta), which is a causative protein of Alzheimer's disease (AD), forms the complex with copper (II) to induce the cholesterol oxidase-like activity by the proton transfer from the cholesterol. In this study, the oxidation of cholesterol by A beta/Cu complex was investigated on the surface of the zwitterionic phospholipid liposome including the bound water advantageous for the enhancement of the proton transfer. The bound water was pooled by the formation of cholesterol-rich domain within liposomes. The resulting reactivity was enhanced by the proton transfer mediated by the bound water. (C) 2009, The Society for Biotechnology, Japan. All rights reserved.

DOI： 10.1016/j.jbiosc.2009.08.003

A Highly-Sensitive Leakage Current Microsensor by Using Denaturant: Detection of Target Protein by DPPC Liposome

P. Lorchirachoonkul, T. Shimanouchi, K. Yamashita, H. Umakoshi, R. Kuboi, M. Noda

EUROSENSORS XXIV CONFERENCE 5 812 - 815 2010

Language：English Publishing type：Research paper (international conference proceedings) Publisher：ELSEVIER SCIENCE BV

We have developed a highly-sensitive leakage current microsensor by using the DPPC liposome entrapping K-4[Fe(CN)(6)] solution to detect existence of biomolecules especially proteins and their dynamic conditions. In this work, the addition of guanidinium hydrochloride (GuHCl) as protein denaturant successfully obtain a prominent improvement in sensitivity by 129-fold of magnitude, although target protein, which is carbonic anhydrase from bovine ( CAB), weakly interacts with liposome under the normal condition. Moreover, we can use it to evaluate the conformation state of CAB protein such as 'Native', 'Molten-Globule' and 'Unfold' states. (C) 2009 Published by Elsevier Ltd.

DOI： 10.1016/j.proeng.2010.09.232

Characterization of Amyloid beta Fibrils with An Aqueous Two-Phase System: Implications of Fibril Formation

Toshinori Shimanouchi, Naoya Shimauchi, Keiichi Nishiyama, Huong Thi Vu, Hisashi Yagi, Yuji Goto, Hiroshi Umakoshi, Ryoichi Kuboi

SOLVENT EXTRACTION RESEARCH AND DEVELOPMENT-JAPAN 17 121 - 128 2010

Language：English Publishing type：Research paper (scientific journal) Publisher：JAPAN ASSOC SOLVENT EXTRACTION

The pathological process of Alzheimer's disease is closely related to amyloid fibril formation by the causative protein, amyloid beta (A beta). The growth behavior of A beta fibrils is predominated by the seeds-monomeric A beta interaction. In this study, the local hydrophobicity of seeds of A beta fibrils was investigated by the aqueous two-phase partitioning method to evaluate the hydrophobic interaction between the seed-monomeric A beta. The seeds showed a high local hydrophobicity relative to the monomer and fibrils. From the fibril growth experiment and the additive effect of Triton X-100, we could demonstrate the contribution of the hydrophobic seeds-monomer interaction to fibril formation.

DOI： 10.15261/serdj.17.121

Oxidative/heat stress enhanced production of chitosanase from Streptomyces griseus cells through its interaction with liposome

Kien Xuan Ngo, Hiroshi Umakoshi, Haruyuki Ishii, Huong Thi Bui, Toshinori Shimanouchi, Ryoichi Kuboi

JOURNAL OF BIOSCIENCE AND BIOENGINEERING 108 ( 6 ) 471 - 476 2009.12

Language：English Publishing type：Research paper (scientific journal) Publisher：SOC BIOSCIENCE BIOENGINEERING JAPAN

The effective production and secretion of chitosanase from S. griseus cells, in the presence of hydrogen peroxide, were studied by the treatment of the cells with 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphatidylcholine (POPC) liposomes under heat condition. The variation of the conformation and activity of the chitosanase caused by the interaction of liposomes with target chitosanase under stress condition was systematically investigated by using circular dichroism (CD) spectra and dielectric dispersion analysis (DDA). The effect of the oxidative stress (hydrogen peroxide) on the lipid and protein peroxide of cell membrane of S. griseus pretreated with and without liposomes under heat stress at 41 degrees C was further carried out. The possible utilization of membrane-membrane interaction between liposomes and cell membrane induced by the heat treatment was further investigated to enhance the production of chitosanase from S. griseus under oxidative stress condition. (C) 2009, The Society for Biotechnology, Japan. All rights reserved.

DOI： 10.1016/j.jbiosc.2009.06.010

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