Kenichi Yoshikawa

Removal of histone tails from nucleosome dissects the physical mechanisms of salt-induced aggregation, linker histone H1-induced compaction, and 30-nm fiber formation of the nucleosome array (2009)

Hizume, Kohji, Nakai, Tonau, Araki, Sumiko, Prieto, Eloise, Yoshikawa, Kenichi, Takeyasu, Kunio

In order to reveal the roles of histone tails in the formation of higher-order chromatin structures, we employed atomic force microscopy (AFM), and an in vitro reconstitution system to examine the...

Self-Sustained Collective Oscillation Generated in an Array of Non-Oscillatory Cells (2008)

Ma, Yue, Yoshikawa, Kenichi

Oscillations represent a ubiquitous phenomenon in biological systems. The conventional models of biological periodic oscillations are usually proposed as interconnecting transcriptional feedback...

Chain Length Dependence on Folding Transition of a Semiflexible Homo-polymer Chain: Appearance of a Core-Shell Structure (2008)

Higuchi, Yuji, Sakaue, Takahiro, Yoshikawa, Kenichi

The folding transition of single, long semiflexible polymers was studied with special emphasis on the chain length effect using Monte Carlo simulations. While a relatively short chain (10-25 Kuhn...

Pleiotrophic functions of Epstein-Barr virus nuclear antigen-1 (EBNA-1) and oriP differentially contribute to the efficiency of transfection/expression of exogenous gene in mammalian cells (2007)

Kishida, Tsunao, Asada, Hidetsugu, Kubo, Koji, Sato, Yuko T., Shin-Ya, Masaharu, Imanishi, Jiro, ...

The EBNA1 gene and oriP sequence, originally derived from the EBV genome, provide plasmid vectors with artificial chromosome (AC)-like characteristics, including cytoplasm-to-nuclear transport,...

Contraction-induced cluster formation in cardiac cell culture (2007)

Harada, Takahiro, Isomura, Akihiro, Yoshikawa, Kenichi

Evolution of the spatial arrangement of cells in a primary culture of cardiac tissue derived from newborn rats was studied experimentally over extended period. It was found that cells attract each...

Dynamical Calling Behavior Experimentally Observed in Japanese Tree Frogs (Hyla japonica) (2007)

AIHARA, Ikkyu, HORAI, Shunsuke, KITAHATA, Hiroyuki, AIHARA, Kazuyuki, YOSHIKAWA, Kenichi

We recorded time series data of calls of Japanese tree frogs (Hyla japonica; Nihon-Ama-Gaeru) and examined the dynamics of the experimentally observed data not only through linear time series...

Extension of a DNA Molecule by Local Heating with a Laser (2007)

Ichikawa, Masatoshi, Ichikawa, Hiroki, Yoshikawa, Kenichi, Kimura, Yasuyuki

Thermal convection and thermophoresis induced by µm-scale local heating are shown to elongate a single DNA molecule. An infrared laser used as a point heat source is converged into a dispersion...

Dynamical Calling Behavior Experimentally Observed in Japanese Tree Frogs (Hyla japonica) (2007)

AIHARA, Ikkyu, HORAI, Shunsuke, KITAHATA, Hiroyuki, AIHARA, Kazuyuki, YOSHIKAWA, Kenichi

We recorded time series data of calls of Japanese tree frogs (Hyla japonica; Nihon-Ama-Gaeru) and examined the dynamics of the experimentally observed data not only through linear time series...

Plastic bottle oscillator: Rhythmicity and mode bifurcation of fluid flow (2007)

Kohira, Masahiro I., Magome, Nobuyuki, Kitahata, Hiroyuki, Yoshikawa, Kenichi

The oscillatory flow of water draining from an upside-down plastic bottle with a thin pipe attached to its head is studied as an example of a dissipative structure generated under...

Dissociation of DNA–polycation complexes by polyanions and polyampholytes (2007)

Shew, Chwen-Yang, Yoshikawa, Kenichi, Ito, Tomoko, Yoshihara, Chieko, Koyama, Yoshiyuki

Both polyanions and polyampholytes cause the dissociation of DNA–polycation complexes in experiments. To elucidate their mechanisms, Monte Carlo simulations have been conducted on a simple model,...

Elucidation of conformational hysteresis on a giant DNA (2007)

Shew, Chwen-Yang, Higuchi, Yuji, Yoshikawa, Kenichi

The conformational behavior of a giant DNA mediated by condensing agents in the bulk solution has been investigated through experimental and theoretical approaches. Experimentally, a pronounced...

Core-shell structures in single flexible-semiflexible block copolymers: Finding the free energy minimum for the folding transition (2007)

Yoshinaga, Natsuhiko, Yoshikawa, Kenichi

We investigate the folding transition of a single diblock copolymer consisting of a semiflexible and a flexible block. We obtain a Saturn-shaped core-shell conformation in the folded state, in which...

Marked differences in volume phase transitions between gel and single molecule in DNA (2007)

Mayama, H., Nakai, T., Takushi, E., Tsujii, K., Yoshikawa, Kenichi

Volume phase transitions of a DNA gel and a single giant DNA chain caused by spermidine3+ (SPD3+) were investigated. The change in volume for the single DNA (V V0 ∼ 10-5) was four orders of...

Survival versus collapse: Abrupt drop of excitability kills the traveling pulse, while gradual change results in adaptation (2007)

Tanaka, Masanobu, Nagahara, Hiroki, Kitahata, Hiroyuki, Krinsky, Valentin, Agladze, Konstantin I., Yoshikawa, Kenichi

Excitable media show changes in their basic characteristics that reflect temporal changes in the environment. In the photosensitive Belousov-Zhabotinsky (BZ) reaction, excitability is decreased by...

Ultradian oscillations of Stat, Smad, and Hes1 expression in response to serum (2007)

Yoshiura, Shigeki, Ohtsuka, Toshiyuki, Takenaka, Yoshiko, Nagahara, Hiroki, Yoshikawa, Kenichi, Kageyama, Ryoichiro

Serum response has been used as a model for studying signaling transduction for many biological events such as cell proliferation and survival. Although expression of many genes is up- or...

Core-shell structures in single flexible-semiflexible block copolymers: Finding the free energy minimum for the folding transition (2007)

Yoshinaga, Natsuhiko, Yoshikawa, Kenichi

We investigate the folding transition of a single diblock copolymer consisting of a semiflexible and a flexible block. We obtain a {\it Saturn-shaped} core-shell conformation in the folded state, in...

Elucidation of Conformational Hysteresis on a Giant DNA (2007)

Shew, Chwen-Yang, Higuchi, Yuji, Yoshikawa, Kenichi

The conformational behavior of a giant DNA mediated by condensing agents in the bulk solution has been investigated through experimental and theoretical approaches. Experimentally, a pronounced...

Topoisomerase II, scaffold component, promotes chromatin compaction in vitro in a linker-histone H1-dependent manner (2007)

Hizume, Kohji, Araki, Sumiko, Yoshikawa, Kenichi, Takeyasu, Kunio

TopoisomeraseII (Topo II) is a major component of chromosomal scaffolds and essential for mitotic chromosome condensation, but the mechanism of this action remains unknown. Here, we used an in vitro...

Mean field theory for the intermolecular and intramolecular conformational transitions of a single flexible polyelectrolyte chain (2007)

Shew, Chwen-Yang, Yoshikawa, Kenichi

The diMarzio theory has been extended to elucidate the intermolecular and intramolecular phase segregations of a single flexible chain polyelectrolyte in dilute salt-free solutions. At the long chain...

How are small ions involved in the compaction of DNA molecules? (2007)

Iwaki, Takafumi, Saito, Takuya, Yoshikawa, Kenichi

DNA is a genetic material found in all life on Earth. DNA is composed of four types of nucleotide subunits, and forms a double-helical one-dimensional polyelectrolyte chain. If we focus on the...

Regular self-motion of a liquid droplet powered by the chemical marangoni effect (2007)

Nagai, Ken, Sumino, Yutaka, Yoshikawa, Kenichi

We describe here our recent work on spontaneous regular motion of liquid droplet powered by the chemical Marangoni effect under spatially symmetric conditions. It is shown that a spontaneously...

Transcription of Giant DNA Complexed with Cationic Nanoparticles as a Simple Model of Chromatin (2007)

Zinchenko, Anatoly A., Luckel, François, Yoshikawa, Kenichi

We prepared complexes of giant double-stranded DNA with cationic nanoparticles of 10–40 nm in diameter as an artificial model of chromatin and characterized the properties of changes in their...

Relationship between apical membrane elasticity and stress fiber organization in fibroblasts analyzed by fluorescence and atomuc force microscopy (2006)

Kidoaki, Satoru, Matsuda, Takehisa, Yoshikawa, Kenichi

To investigate the relationship between cellular microelasticity and the structural features of cytoskeletons (CSKs), a microindentation test for apical cell membranes and observation of the...

Cell-free protein synthesis at high temperatures using the lysate of a hyperthermophile (2006)

Endoh, Takashi, Kanai, Tamotsu, Sato, Yuko T., Liu, David V., Yoshikawa, Kenichi, Atomi, Haruyuki, ...

Systems for cell-free protein synthesis available today are usually based on the lysates of either Escherichia coli, wheat germ or rabbit reticulocyte, and protein synthesis reactions using these...

Rhythmic motion of a droplet under a dc electric field (2006)

Hase, Masahiko, Watanabe, Shun N., Yoshikawa, Kenichi

Excitable media show changes in their basic characteristics that reflect temporal changes in the environment. In the photosensitive Belousov-Zhabotinsky (BZ) reaction, excitability is decreased by...

Probing biopolymer conformation by metallization with noble metals (2006)

Chen, Ning, Zinchenko, Anatoly A, Yoshikawa, Kenichi

We propose a novel method for the simple visual (colorimetric) and spectroscopic monitoring of the conformational state of a biopolymer. We present an experimental example of the detection of the...

Toward the stable optical trapping of a droplet with counter laser beams under microgravity (2006)

Isomura, Akihiro, Magome, Nobuyuki, Kohira, Masahiro I., Yoshikawa, Kenichi

To identify the optimum conditions for the optical trapping of a droplet under microgravity, we theoretically analyzed the efficiency of trapping with counter laser beams. We found that the distance...

On the formation of rings-on-a-string conformations in a single polyelectrolyte chain: A possible scenario (2006)

Sakaue, Takahiro, Yoshikawa, Kenichi

Recent single-molecular observations have revealed that a single giant DNA molecule assumes (micro) phase separated structures upon the addition of condensing agents. Electron and atomic force...

Na+ more strongly inhibits DNA compaction by spermidine (3+) than K+ (2006)

Hibino, Kumiko, Yoshikawa, Yuko, Murata, Shizuaki, Saito, Takuya, Zinchenko, Anatoly A., Yoshikawa, Kenichi

The protective effects of alkali metal ions (Li+, Na+, K+, Rb+ and Cs+) against spermidine-induced DNA compaction were studied using single-molecule observations. We found that all alkali metal salts...

Transport of a cell-sized phospholipid micro-container across water/oil interface (2006)

Hase, Masahiko, Yamada, Ayako, Hamada, Tsutomu, Yoshikawa, Kenichi

When a cell-sized water droplet, with a diameter of several tens of μm, is placed in oil containing phospholipids, a phospholipid monolayer is formed spontaneously on the droplet surface to produce...

Toward the Stable Optical Trapping of a Droplet with Counter Laser Beams under Microgravity (2006)

Isomura, Akihiro, Magome, Nobuyuki, Kohira, Masahiro I., Yoshikawa, Kenichi

To identify the optimum conditions for the optical trapping of a droplet under microgravity, we theoretically analyzed the efficiency of trapping with counter laser beams. We found that the distance...

Micro-Bioreactor Mimicking a Cellular Environment (2006)

Hase, Masahiko, Yamada, Ayako, Hamada, Tsutomu, Yoshikawa, Kenichi

We report that a cell-sized water droplet (CWD) with a diameter of several tens of microns can serve as a micro-biochemical reactor. Since the droplet inner surface is covered by a phospholipid...

Hyaluronic acid and its derivative as a multi-functional gene expression enhancer: Protection from non-specific interactions, adhesion to targeted cells, and transcriptional activation (2006)

Ito, Tomoko, Iida-Tanaka, Naoko, Niidome, Takuro, Kawano, Takahito, Kubo, Koji, Yoshikawa, Kenichi, ...

Hyaluronic acid (HA), a natural anionic mucopolysaccharide, can be deposited onto the cationic surface of DNA/polyethyleneimine (PEI) complexes to recharge the surface potential and reduce...

Structural transition of actin filament in a cell-sized water droplet with a phospholipid membrane (2006)

Hase, M., Yoshikawa, Kenichi

Actin filament, F -actin, is a semiflexible polymer with a negative charge, and is one of the main constituents of cell membranes. To clarify the effect of cross talk between a phospholipid membrane...

Protective effect of vitamin C against double-strand breaks in reconstituted chromatin visualized by single-molecule observation (2006)

Yoshikawa, Yuko, Hizume, Kohji, Oda, Yoshiko, Takeyasu, Kunio, Araki, Sumiko, Yoshikawa, Kenichi

Direct attack to genomic DNA by reactive oxygen species causes various types of lesions, including base modi. cations and strand breaks. The most significant lesion is considered to be an unrepaired...

Elongation/compaction of giant DNA caused by depletion interaction with a flexible polymer (2006)

Kojima, Masahiro, Kubo, K., Yoshikawa, Kenichi

Structural changes in giant DNA induced by the addition of the flexible polymer Polyethylene Glycol (PEG) were examined by the method of single-DNA observation. In dilute DNA conditions, individual...

Transporting of a Cell-Sized Phospholipid Vesicle Across Water/Oil Interface (2006)

Hase, Masahiko, Yamada, Ayako, Hamada, Tsutomu, Yoshikawa, Kenichi

When a cell-sized water droplet, with a diameter of several tens of micro meter, is placed in oil containing phospholipids, a stable cell-sized vesicle is spontaneously formed as a water-in-oil...

Hydrodynamic radius of circular DNA is larger than that of linear DNA (2006)

Araki, Sumiko, Nakai, Tonau, Hizume, Kohji, Takeyasu, Kunio, Yoshikawa, Kenichi

It is generally accepted that linear polymers are larger, such as with regard to the end-to-end distance and gyration radius, than the corresponding circular polymers. We measured the Brownian motion...

Domain-Growth Kinetics in a Cell-sized Liposome (2006)

SAEKI, Daisuke, HAMADA, Tsutomu, YOSHIKAWA, Kenichi

We investigated the kinetics of domain growth on liposomes caused by decreasing the temperature; the liposomes consisted of a ternary mixture (unsaturated phospholipid, saturated phospholipid, and...

Real-time imaging of the somite segmentation clock: Revelation of unstable oscillators in the individual presomitic mesoderm cells (2006)

Masamizu, Yoshito, Ohtsuka, Toshiyuki, Takashima, Yoshiki, Nagahara, Hiroki, Takenaka, Yoshiko, Yoshikawa, Kenichi, ...

Expression of the bHLH gene Hes1 oscillates stably in the presomitic mesoderm (PSM) while transiently in other cells, suggesting that the Hes1 oscillators in the former and the latter could be...

An oil droplet that spontaneously climbs up stairs (2006)

Sumino, Yutaka, Magome, Nobuyuki, Yoshikawa, Kenichi

It has been reported that an oil droplet on a glass surface moves spontaneously in an oil-water system. This motion of an oil droplet can be understood as the spreading of a reactive droplet, which...

Change in the mode of spontaneous motion of an alcohol droplet caused by a temperature change (2006)

Nagai, Ken, Sumino, Yutaka, Kitahata, Hiroyuki, Yoshikawa, Kenichi

An alcohol (pentanol) droplet exhibits spontaneous motion on an aqueous solution, driven by a solutal Marangoni effect. We found that the mode of such droplet motion changes depending on the...

Domain Growth Kinetics in a Cell-sized Liposome (2005)

Saeki, Daisuke, Hamada, Tsutomu, Yoshikawa, Kenichi

We investigated the kinetics of domain growth on liposomes consisting of a ternary mixture (unsaturated phospholipid, saturated phospholipid, and cholesterol) by temperature jump. The domain growth...

Chemosensitive running droplet (2005)

Sumino, Yutaka, Kitahata, Hiroyuki, Yoshikawa, Kenichi, Nagayama, Masaharu, Nomura, Shin-Ichiro M., Magome, Nobuyuki, ...

Chemical control of the spontaneous motion of a reactive oil droplet moving on a glass substrate under an aqueous phase is reported. Experimental results show that the self-motion of an oil droplet...

Optical Levitation of a Droplet under Linear Increase of Gravitational Acceleration (2005)

Kohira, Masahiro I., Isomura, Akihiro, Magome, Nobuyuki, Mukai, Sadaatsu, Yoshikawa, Kenichi

Optical levitation of a liquid droplet in gas phase was investigated under timedependent change of the gravitational acceleration with specific flight pattern of an airplane. Through multiple trials...

Reversible photo-switching in a cell-sized vesicle (2005)

Hamada, Tsutomu, Sato, Yuko T., Nagasaki, Takeshi, Yoshikawa, Kenichi

A photosensitive amphiphilic molecule can switch the shape of an assembled vesicle as determined by microscopic observation. Photo-isomerization induces a change in membrane fluctuation behavior or a...

Chemo-Sensitive Running Droplet (2005)

Sumino, Yutaka, Nagayama, Masaharu, Kitahata, Hiroyuki, Nomura, Shin-ichiro M., Magome, Nobuyuki, Mori, Yoshihito, ...

Chemical control of the spontaneous motion of a reactive oil droplet moving on a glass substrate under an aqueous phase is reported. Experimental results show that the self-motion of an oil droplet...

Smooth/rough layering in liquid-crystalline/gel state of dry phospholipid film, in relation to its ability to generate giant vesicles (2005)

Hishida, Mafumi, Seto, Hideki, Yoshikawa, Kenichi

Morphological changes in a dry phospholipid film on a solid substrate were studied below and above the main transition temperature, between the gel and liquid-crystalline phases by phase-contrast...

Dynamics of micrometer-scale phase separation in a polymer mixture upon laser irradiation (2005)

Toyama, Hirofumi, Kitahata, Hiroyuki, Yoshikawa, Kenichi

Ten $\mu$m -sized droplets in an aqueous-two-phase system (water/ polyethylene-glycol (PEG)/ dextran) dissapear upon irradiation with a focused YAG laser. The interface of the dextran-rich droplet...

Mode Selection in the Spontaneous Motion of an Alcohol Droplet (2005)

Nagai, Ken, Sumino, Yutaka, Kitahata, Hiroyuki, Yoshikawa, Kenichi

An alcohol (pentanol) droplet exhibits spontaneous agitation on an aqueous solution, driven by a solutal Marangoni effect. We found that the droplet's mode of motion is controlled by its volume. A...

Why is the condensed phase of DNA preferred at higher temperature? DNA compaction in the presence of a multivalent cation (2004)

Saito, Takuya, Iwaki, Takafumi, Yoshikawa, Kenichi

Upon the addition of multivalent cations, a giant DNA chain exhibits a large discrete transition from an elongated coil into a folded compact state. We performed single-chain observation of long DNAs...

Different pathways in mechanical unfolding/folding cycle of a single semiflexible polymer (2004)

Yoshinaga, Natsuhiko, Yoshikawa, Kenichi, Ohta, Takao

Kinetics of conformational change of a semiflexible polymer under mechanical external field were investigated with Langevin dynamics simulations. It is found that a semiflexible polymer exhibits...

Entrapping a polymer chain in a light well under a good solvent condition (2004)

Ichikawa, Masatoshi, Yoshikawa, Kenichi, Matsuzawa, Yukiko

During the last decade, the laser trapping technique has been actively applied to elucidate the property of macromolecules, DNA, RNA, cytoskeleton fibres, etc. Due to the inherent difficulty in the...

All-or-none switching of transcriptional activity on single DNA molecules caused by a discrete conformational transition (2004)

Yamada, Ayako, Kubo, Koji, Nakai, Tonau, Tsumoto, Kanta, Yoshikawa, Kenichi

Recently, it has been confirmed that long duplex DNA molecules with sizes larger than several tens of kilo-base pairs (kbp), exhibit a discrete conformational transition from an elongated coil state...

Slowing and stopping of chemical waves in a narrowing canal (2004)

Kitahata, Hiroyuki, Aihara, Ryoichi, Mori, Yoshihito, Yoshikawa, Kenichi

The propagation of a chemical wave in a narrow, cone-shaped glass capillary was investigated. When a chemical wave propagates from the wider end to the narrower end, it slows, stops, and then...

Phase Transition in Reconstituted Chromatin (2004)

Nakai, Tonau, Hizume, Kohji, Yoshimura, Shige. H., Takeyasu, Kunio, Yoshikawa, Kenichi

By observing reconstituted chromatin by fluorescence microscopy (FM) and atomic force microscopy (AFM), we found that the density of nucleosomes exhibits a bimodal profile, i.e., there is a large...

Self Running Droplet: Emergence of Regular Motion from Nonequilibrium Noise (2004)

Sumino, Yutaka, Magome, Nobuyuki, Hamada, Tsutomu, Yoshikawa, Kenichi

Spontaneous motion of an oil droplet driven by chemical nonequilibricity is reported. It is shown that the droplet undergoes regular rhythmic motion under appropriately designed boundary conditions,...

Direction Detector on an Excitable Field: Field Computation with Coincidence Detection (2004)

Nagahara, Hiroki, Ichino, Takatoshi, Yoshikawa, Kenichi

Living organisms process information without any central control unit and without any ruling clock. We have been studying a novel computational strategy that uses a geometrically arranged excitable...

Structural changes in block copolymer solution under shear flow as determined by nonequilibrium molecular dynamics (2003)

Rychkov, Igor, Yoshikawa, Kenichi

A nonequilibrium molecular dynamics computer simulation on microsegregated solutions of symmetrical diblock copolymers is reported. As the polymer concentration increases, the system undergoes phase...

Fluorescence microscopic visualization of a DNA-cationic fullerene complex (2000)

Yamashita, Kenichi, Iwataki, Toshio, Hatta, Taizo, Yoshikawa, Kenichi, Tsuge, Otohiko, Takagi, Makoto, ...

Cationic fullerene derivative 1, which is soluble in aqueous medium, bound to double stranded DNA. Observation of Coliphage T4 DNA in the absence and presence of 1 by fluorescence microscopy...

Folding transition of long duplex DNA from mammalian cells (1999)

Yoshikawa, Yuko, Kanbe, Toshio, Yoshikawa, Kenichi

Conformational change in individual giant DNAs from pig liver is studied by use of fluorescence microscopy. With the addition of spermidine (a trivalent amine), each DNA chains undergo abrupt...

Dielectric Control of Counterion-Induced Single-Chain Folding Transition of DNA

Baigl, Damien, Yoshikawa, Kenichi

In the presence of condensing agents, single chains of giant double-stranded DNA undergo a first-order phase transition between an elongated coil state and a folded compact state. To connect this...

Na+ Shows a Markedly Higher Potential than K+ in DNA Compaction in a Crowded Environment

Zinchenko, Anatoly A., Yoshikawa, Kenichi

Whereas many physicochemical investigations have shown that among monovalent cations Na+ ion possesses minimal potential for DNA binding, biological assays have shown that Na+ ion (in contrast to K+...

Real-time imaging of the somite segmentation clock: Revelation of unstable oscillators in the individual presomitic mesoderm cells

Masamizu, Yoshito, Ohtsuka, Toshiyuki, Takashima, Yoshiki, Nagahara, Hiroki, Takenaka, Yoshiko, Yoshikawa, Kenichi, ...

Notch signaling components such as the basic helix-loop-helix gene Hes1 are cyclically expressed by negative feedback in the presomitic mesoderm (PSM) and constitute the somite segmentation clock....

Dielectric Control of Counterion-Induced Single-Chain Folding Transition of DNA

Baigl, Damien, Yoshikawa, Kenichi

In the presence of condensing agents, single chains of giant double-stranded DNA undergo a first-order phase transition between an elongated coil state and a folded compact state. To connect this...

Na+ Shows a Markedly Higher Potential than K+ in DNA Compaction in a Crowded Environment

Zinchenko, Anatoly A., Yoshikawa, Kenichi

Whereas many physicochemical investigations have shown that among monovalent cations Na+ ion possesses minimal potential for DNA binding, biological assays have shown that Na+ ion (in contrast to K+...

Real-time imaging of the somite segmentation clock: Revelation of unstable oscillators in the individual presomitic mesoderm cells

Masamizu, Yoshito, Ohtsuka, Toshiyuki, Takashima, Yoshiki, Nagahara, Hiroki, Takenaka, Yoshiko, Yoshikawa, Kenichi, ...

Notch signaling components such as the basic helix-loop-helix gene Hes1 are cyclically expressed by negative feedback in the presomitic mesoderm (PSM) and constitute the somite segmentation clock....

Protective Effect of Vitamin C against Double-Strand Breaks in Reconstituted Chromatin Visualized by Single-Molecule Observation

Yoshikawa, Yuko, Hizume, Kohji, Oda, Yoshiko, Takeyasu, Kunio, Araki, Sumiko, Yoshikawa, Kenichi

Direct attack to genomic DNA by reactive oxygen species causes various types of lesions, including base modifications and strand breaks. The most significant lesion is considered to be an unrepaired...

Chemosensitive running droplet

Sumino, Yutaka, Kitahata, Hiroyuki, Yoshikawa, Kenichi, Nagayama, Masaharu, Nomura, Shin-Ichiro M., Magome, Nobuyuki, ...

Chemical control of the spontaneous motion of a reactive oil droplet moving on a glass substrate under an aqueous phase is reported. Experimental results show that the self-motion of an oil droplet...

Topoisomerase II, scaffold component, promotes chromatin compaction in vitro in a linker-histone H1-dependent manner

Hizume, Kohji, Araki, Sumiko, Yoshikawa, Kenichi, Takeyasu, Kunio

TopoisomeraseII (Topo II) is a major component of chromosomal scaffolds and essential for mitotic chromosome condensation, but the mechanism of this action remains unknown. Here, we used an in vitro...

Ultradian oscillations of Stat, Smad, and Hes1 expression in response to serum

Yoshiura, Shigeki, Ohtsuka, Toshiyuki, Takenaka, Yoshiko, Nagahara, Hiroki, Yoshikawa, Kenichi, Kageyama, Ryoichiro

Serum response has been used as a model for studying signaling transduction for many biological events such as cell proliferation and survival. Although expression of many genes is up- or...

Transcription of Giant DNA Complexed with Cationic Nanoparticles as a Simple Model of Chromatin

Zinchenko, Anatoly A., Luckel, François, Yoshikawa, Kenichi

We prepared complexes of giant double-stranded DNA with cationic nanoparticles of 10–40 nm in diameter as an artificial model of chromatin and characterized the properties of changes in their...

ATP-Induced Shrinkage of DNA with MukB Protein and the MukBEF Complex of Escherichia coli▿

Chen, Ning, Zinchenko, Anatoly A., Yoshikawa, Yuko, Araki, Sumiko, Adachi, Shun, Yamazoe, Mitsuyoshi, ...

Fluorescence microscopic observation of individual T4 DNA molecules revealed that the MukBEF complex (bacterial condensin) and its subunit, the MukB (a member of the SMC [structural maintenance of...