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Journal Articles

Contrast variation by dynamic nuclear polarization and time-of-flight small-angle neutron scattering, 1; Application to industrial multi-component nanocomposites

Noda, Yohei*; Koizumi, Satoshi*; Masui, Tomomi*; Mashita, Ryo*; Kishimoto, Hiromichi*; Yamaguchi, Daisuke; Kumada, Takayuki; Takata, Shinichi; Oishi, Kazuki*; Suzuki, Junichi*

Journal of Applied Crystallography, 49(6), p.2036 - 2045, 2016/12

 Times Cited Count:17 Percentile:79.08(Chemistry, Multidisciplinary)

Oral presentation

Observation of nanodomains in model biomembranes using small angle neutron scattering techniques

Masui, Tomomi; Imai, Masayuki*; Urakami, Naohito*

no journal, , 

no abstracts in English

Oral presentation

Ultra-small-angle neutron scattering study of Actin-Polymer complexes formation

Masui, Tomomi; Koizumi, Satoshi; Hashimoto, Takeji; Iwase, Hiroki; Shikinaka, Kazuhiro*; Kwon, H.*; Kakugo, Akira*; Gong, J.*

no journal, , 

no abstracts in English

Oral presentation

The Structure formation of filamentous actin and polycation complex

Masui, Tomomi; Shikinaka, Kazuhiro*; Kwon, H.*; Koizumi, Satoshi; Hashimoto, Takeji; Iwase, Hiroki; Kakugo, Akira*; Gong, J.*

no journal, , 

no abstracts in English

Oral presentation

Ultra-small angle neutron scattering observation of filamentous actin and polycation complex

Masui, Tomomi; Shikinaka, Kazuhiro*; Kwon, H.*; Koizumi, Satoshi; Hashimoto, Takeji; Iwase, Hiroki; Kakugo, Akira*; Gong, J.*

no journal, , 

no abstracts in English

Oral presentation

In situ observation on hierarchical actin bundle network

Masui, Tomomi; Shikinaka, Kazuhiro*; Kwon, H.*; Koizumi, Satoshi; Hashimoto, Takeji; Iwase, Hiroki; Kakugo, Akira*; Gong, J.*

no journal, , 

Actin is one of the most abundant cytoskeleton proteins in eucaryotic cell. They play a crucialrole in cell motility by polymerizing monomeric globular G-actin into polymeric filamentous actin (F-actin). With actin-binding proteins (ABPs), they form higher order structures such as linear bundles, two-dimensional networks and three-dimensional gels. It has been considered that these structures are controlled by ABPs. However recent study have shown that the only one kind of artificial cationic polymer can form variety of structures depending its concentration and salt concentration. This system is a good model to elucidate the mechanism of regulation of actin and ABPs complex structure. Based on these backgrounds, we have investigated the effects of salt concentration on the stability and structure of actin-polycation complexes by using small angle neutron scattering (SANS) technique.

Oral presentation

The Observation of structure formation of F-actin

Masui, Tomomi; Shikinaka, Kazuhiro*; Kwon, H.*; Koizumi, Satoshi; Hashimoto, Takeji; Iwase, Hiroki; Kakugo, Akira*; Gong, J.*

no journal, , 

no abstracts in English

Oral presentation

In situ observation on hierarchical actin bundle networks; Salt concentration effects

Masui, Tomomi; Shikinaka, Kazuhiro*; Kwon, H.*; Koizumi, Satoshi; Hashimoto, Takeji; Iwase, Hiroki; Kakugo, Akira*; Gong, J.*

no journal, , 

Actin is one of the cytoskeleton proteins and it is most abundant proteins in eucaryotic cell. They play a crucial role in cell motility by polymerization of monomeric globular G-actin into polymeric filamentous actin (F-actin). With actin binding proteins, they form various structures such as linear bundles, two-dimensional networks, and three-dimensional gels. It has been considered that these structures are controlled by the specific interaction between actin and binding protein. However from the physicochemical point of view, actin has negative charge and actin-binding protein has positive charge. Thus, the electrostatic interaction might play important role to determinein the structure. Based on this idea, we have investigated the effects of salt concentration on the stability and structure of actin-polymer complexes by using small angle neutron scattering (SANS) technique.

Oral presentation

Assembly and disassembly of actin and cationic polymer complex

Masui, Tomomi; Shikinaka, Kazuhiro*; Kwon, H.*; Koizumi, Satoshi; Hashimoto, Takeji; Iwase, Hiroki; Kakugo, Akira*; Gong, J.*

no journal, , 

Actin is one of the cytoskeleton proteins and it is most abundant proteins in eucaryotic cell. They play a crucial role in cell motility by polymerization of monomeric globular G-actin into polymeric filamentous actin (F-actin). With actin binding proteins, they form various structures such as linear bundles, two-dimensional networks, and three-dimensional gels. It has been considered that these structures are controlled by the specific interaction between actin and binding protein. However from the physicochemical point of view, actin has negative charge and actin-binding protein has positive charge. Thus, the electrostatic interaction might play important role to determine in the structure. Based on this idea, we have investigated the effects of salt concentration on the stability and structure of actin-polymer complexes by using small angle neutron scattering (SANS) technique.

Oral presentation

Assembly and disassembly of model cytoskeleton system

Masui, Tomomi; Shikinaka, Kazuhiro*; Kwon, H.*; Koizumi, Satoshi; Hashimoto, Takeji; Iwase, Hiroki; Kakugo, Akira*; Gong, J.*

no journal, , 

Actin is one of the most abundant cytoskeleton proteins in eucaryotic cell. They play a crucial role in cell motility by polymerizing monomeric globular G-actin into polymeric filamentous actin (F-actin). Withactin-binding proteins (ABPs), they form higher order structures such as linear bundles, two-dimensional networks and three-dimensional gels. In this study we have constructed model cytoskeleton system composed of F-actin, cationic polymer and salt. To investigate salt induced hierarchical structure change we employed fluorescence microscopy and small angle neutron scattering (SANS) technique.

Oral presentation

The Effect of salt on the hierarchical structure of F-actin/polycation complexes; In situ observation by fluorescnece microscopy and small angle neutron scattering

Masui, Tomomi; Shikinaka, Kazuhiro*; Koizumi, Satoshi; Hashimoto, Takeji; Kakugo, Akira*; Gong, J.*; Kwon, H.*

no journal, , 

We reconstituted in vitro model cytoskeleton using F-actin and polycation. We have investigated hierarchical structural change of F-actin/polycation complexes induced by salt quantitatively by fluorescence microscopy and small angle neutron scattering. Based on the obtained structural parameters, we will discuss dominant interactions which determine the structure.

Oral presentation

Multiple scattering from granular specimen observed in the ultra-small-angle scattering region

Yamaguchi, Daisuke; Nakahara, Akio*; Matsuo, Yosuke*; Koizumi, Satoshi; Masui, Tomomi; Hashimoto, Takeji

no journal, , 

The hierarchical structure related to the crack pattern formed in the drying process of granular specimen was investigated by using ultra-small-angle and small-angle neutron scattering. We prepared two kinds of granular specimens; one is made of CaCO$$_{3}$$ and the other is made of MgO. CaCO$$_{3}$$ granular consists of spherical particles of which diameter ranges from ca. 0.5 micron to 5 micron, while MgO granular consists of plate particles of which diameter and thickness are ca. 0.5 - 1 micron, and ca. 50 nm, respectively. According to the difference in the shape of constituent particles, the crack patterns formed in the CaCO$$_{3}$$ and MgO granular specimens are different. Detailed analysis of neutron scattering data revealed that there exist a considerable multiple scattering as well as anomalous excess scattering in the ultra small angle scattering region (q $$<$$ 2 $$times$$ 10 $$^{-4}$$ (nm$$^{-1}$$)) which may reflect the microstructure related to the unique crack patterns of granular specimens.

Oral presentation

Salt induced hierarchical morphology change of actin/polycation complexes

Masui, Tomomi; Shikinaka, Kazuhiro*; Koizumi, Satoshi; Kakugo, Akira*; Hashimoto, Takeji; Gong, J.*

no journal, , 

Hierarchical structures of F-actin, an anionic polyelectrolyte, and PDMAPAA-Q, a synthetic linear cationic polyelectrolyte (polycation), complexes in KCl salt solutions have been examined over a wide range of length scales from nanometer to micrometer using a combination of ultra-small-angle neutron scattering technique and fluorescence microscopy. We found hierarchical condensation of actin/polycation complex composed of a superbundle of 10 micrometer, protobundle of 100 nanometer, and protofilament (F-actin) of nanometer. These structures are largely influenced by salt concentrations. With increase of salt concentration superbundle structure changes from globular to extended states, simultaneously, the regularity of F-actin inside the protobundle increased and protobundle size increased about ten times larger. Further increase of salt concentration brings the protobundle disassemble to single F-actin.

Oral presentation

Mechanism of water absorption in microbial cellulose; Hierarchical amorphous structure and capillarity

Koizumi, Satoshi; Tomita, Yoko*; Zhao, Y.; Iwase, Hiroki*; Yamaguchi, Daisuke; Kondo, Tetsuo*; Hashimoto, Takeji; Masui, Tomomi

no journal, , 

no abstracts in English

Oral presentation

Advanced technique of ultra-small-angle neutron scattering explores a new scientific field of neutron cell biology, covering from a single molecule to cell

Koizumi, Satoshi; Masui, Tomomi; Yamaguchi, Daisuke; Hashimoto, Takeji; Iwase, Hiroki*

no journal, , 

no abstracts in English

Oral presentation

Effects of sugars on the structures and dynamics of lipid membranes

Masui, Tomomi; Fujiwara, Satoru; Nakagawa, Hiroshi; Kataoka, Mikio

no journal, , 

Keeping cells in aqueous environment is essential for organisms to be alive. Desiccation damages the cells severely, and causes death of most organisms. Some organisms, however, known to survive under such arid conditions. This desiccation tolerance has been known to be related to the production of sugars in these organisms. In this study, we investigate the effect of trehalose on the structure and dynamics of lipid membranes in the solution condition by employing small and wide angle X-ray scattering and neutron spin echo technique. These experimental data represent the trehalose disorder the lamellar structure and decrease the bending rigidity of membrane.

Oral presentation

Effects of trehalose on the structures and dynamics of lipid membranes

Masui, Tomomi; Fujiwara, Satoru; Nakagawa, Hiroshi; Kataoka, Mikio

no journal, , 

It is known that trehalose is a protective reagent and plays important roles in desiccation tolerance. One of the important properties of trehalose for the desiccation tolerance is stabilization of the biomembranes in the fluid phase. However, due to lack of information of how the trehalose molecules distribute on the biomembrane and interact with lipid molecules, the preservation mechanism of the biomembrane by trehalose has not been elucidated. Here we aimed at determining the distribution of trehalose on the simple model biomembrane and characterize dynamic properties of the membrane and the lipid molecules. For this purpose we employed small- and wide-angle X-ray scattering (SAXS and WAXS) and neutron spin echo (NSE) techniques. The NSE measurement revealed that the addition of trehalose to lipid membrane decreases the bending rigidity. This effect of trehalose is same tendency of temperature.

Oral presentation

Effect of trehalose on the structure and dynamics of lipid membranes

Masui, Tomomi; Fujiwara, Satoru; Endo, Hitoshi; Nakagawa, Hiroshi; Kataoka, Mikio

no journal, , 

Water is essential for organisms and desiccation damages the cells severely, and causes death of most organisms. Some organisms, however, known to survive under such arid conditions. This desiccation tolerance has been known to be related to the production of sugars in these organisms. One property which is important for the desiccation tolerance is stabilization of the cell membranes in the fluid phase by limiting the dehydration-induced increase in the gel-fluid transition temperature of the membranes. The membranes not only act as a barrier within or around a cell, but also control transfer of substances across the membranes. Elucidating how sugars interact with the membranes is therefore important for understanding the molecular mechanism of the desiccation tolerance. We investigated the effects of the sugars on the structures and the dynamics of the lipid membranes by small- and wide-angle X-ray scattering (SAXS and WAXS), and neutron spin-echo (NSE), techniques.

Oral presentation

Contrast variation SANS by proton spin polarization; Upgrade and use at J-PARC

Noda, Yohei; Yamaguchi, Daisuke; Shamoto, Shinichi; Hashimoto, Takeji; Kumada, Takayuki; Takata, Shinichi; Koizumi, Satoshi; Oishi, Kazuki*; Suzuki, Junichi*; Masui, Tomomi*; et al.

no journal, , 

We have developed proton spin polarization technique for contrast variation in small angle neutron scattering (SANS), which utilizes that neutron scattering section can be controlled by polarizing proton spins. Consequently, we succeeded in the analysis of nano-structure in multi-component samples. We will report the detail of our recent activity for getting higher proton spin oplarization. The recent results of SANS measurement with proton spin polarization conducted for the first time at TAIKAN in J-PARC will also be reported.

Oral presentation

The First experiment of spin contrast variation SANS at J-PARC BL15 TAIKAN

Noda, Yohei; Yamaguchi, Daisuke; Shamoto, Shinichi; Hashimoto, Takeji; Kumada, Takayuki; Takata, Shinichi; Koizumi, Satoshi*; Oishi, Kazuki*; Suzuki, Junichi*; Masui, Tomomi*; et al.

no journal, , 

Neutron scattering length changes as aligning the spin direction of protons in a sample. By use of this phenomenon, we have developed spin contrast variation technique for studying nano-scale structure formed in multi-component systems. In this presentation, we report the results of our recent experiment at J-PARC TAIKAN.

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