Biomedical subjects

Koichiro Matsuno

Publications and source records attributed to Koichiro Matsuno.

12 recordsLinked to original sources

PubMed2006

Forming and maintaining a heat engine for quantum biology.

Chemical reactions upholding biological functions and structures are the process of measurement taking place among the participating chemical reactants. Chemical reactions occurring in thermal environments are either endothermic or exothermic. In particular, exothermic reactions that can live with temperature gradients of exogenous origin could potentially be competent enough to synthesize a robust quantum as a heat engine. Molecular organizations leading to the origin of the phenomenon of life might have been associated with the emergence of a quantum coherence embodied in a robust heat engine feeding on quantum decoherence. Evolutionary maintenance of a robust quantum heat engine, once appeared, can further be empowered by the build-up of temperature gradients of endogenous origin. Biology enriches the repertoire of quantum mechanics so as to include a robust heat engine as a legitimate member of a quantum in addition to the already established member of a quantum including an atom, molecule, and macromolecule.

Adenosine Triphosphate↗

PubMed2005

Fourier's law of heat transfer and its implication to cell motility.

Fourier's law of heat transfer addressing temperature differences is intrinsically selective in favoring the mitigation of the differences proceeding as fast as possible. We present an experimental demonstration of such selective behavior of material origin. When an actin filament equipped with nano-scale heat acceptors was placed under heat pulsation, it demonstrated a unidirectional movement without the presence of myosin or ATP. The prime factor for the unidirectional movement was the temperature differences between the locally heated portions on the actin filament and the cooler material bodies in the surroundings. The unidirectional movement could be enhanced in the process of mitigating the temperature differences as fast as possible.

Actin Cytoskeleton↗

PubMed2005

Enantiomeric excess of amino acids in hydrothermal environments.

In a simulated hydrothermal environment allowing fluid circulation between hot and cold regions repeatedly, D- and L-alanine molecules were racemized differently depending upon the concentration of alanine, whether D or L, present in the solution. In particular, the relative population of L-alanine was slightly more enhanced compared to that of D-alanine when the concentration of alanine increased. Enantiomeric excess of L-alanine was also observed when metallic ions such as zinc were sufficiently present in the environments. Hydrothermal environments in the primitive ocean could have maintained the capacity of selectively retaining enantiomeric excess in favor of L-amino acids once the concentration of amino acids could reach a sufficiently high level.

Alanine↗

PubMed2005

Evolving lipid vesicles in prebiotic hydrothermal environments.

We compared three different kinds of lipid vesicles made of saturated fatty acids, unsaturated fatty acids, and phospholipids for their evolutionary capabilities in a simulated hydrothermal environment. Encapsulation of the glycine monomers enhanced the oligomerization of peptides in all cases. Fatty acid vesicles remained stable at higher temperatures and efficiently utilized heat energy for this synthetic reaction. Phospholipid vesicles were destabilized by higher temperatures, and thus were found to be better suited to enhance synthetic reactions at lower temperatures.

1,2-Dipalmitoylphosphatidylcholine↗

PubMed2004

Enhancing the staggered fluctuations of an actin filament sliding on Chara myosin.

We examined both longitudinal and transversal fluctuations of displacements of an actin filament sliding upon Chara myosin molecules. Although the magnitude of transversal fluctuations remained rather independent of ATP concentration, the longitudinal ones were found to increase their magnitude as the concentration increased. In addition, the longitudinal fluctuations gradually increased as the sliding velocity of the filament increased.

Actin Cytoskeleton↗

PubMed2004

Transition from contractile to protractile distortions occurring along an actin filament sliding on myosin molecules.

An ATP-activated actin filament sliding on myosin molecules exhibited mechanical distortions or fluctuations both longitudinally and transversally along the filament. Although actin filaments exhibited a uniform sliding movement longitudinally as the ATP concentration increased, the longitudinal fluctuations were found to vary their magnitude with the concentration. The magnitude of longitudinal fluctuations reached its maximum at approximately 100 microM of the ATP concentration. The local enhancement of the longitudinal fluctuations as responding to changes in the ATP concentration is associated with a critical phenomenon bridging the two different kinds of mechanical distortions, either contractile or protractile ones, occurring within a sliding actin filament.

Actins↗

PubMed2004

Phosphorylation of nucleotide molecules in hydrothermal environments.

Phosphorylation of AMP into ADP and ATP, that can outrun their hydrolysis, was made possible in a simulated hydrothermal environment when trimetaphosphate was used as the phosphate source. The best yields of phosphorylated products were obtained when the reaction fluids whose temperature was set at about 100 degrees centigrade was injected into the cold environment maintained at 0 degree in a recycling manner. Hydrothermal environments in the primitive ocean could also have served as prebiotic sites for phosphorylation, among others.

Adenine Nucleotides↗

PubMed2003

Enhancement of the sliding velocity of actin filaments in the presence of ATP analogue: AMP-PNP.

The sliding velocity of actin filaments was found to increase in the presence of ATP analogues. At 0.5 mM ATP, the presence of 2.0 mM of AMP-PNP enhanced the filament velocity from 3.2 up to 4.5 microm/s. However, 2 mM ADP decreased the velocity down to 1.1 microm/s. The results suggest that the complex conformations of myosin cross-bridges interacting with an actin filament in the presence of ATP analogues makes the entire filament move faster.

Actin Cytoskeleton↗

PubMed2003

Amplification of diverse catalytic properties of evolving molecules in a simulated hydrothermal environment.

We observed chemical evolution in a mixture of four amino acids, glycine, L-alanine, L-valine and L-aspartic acid, circulated through a flow reactor simulating the thermodynamic conditions of a hydrothermal environment. These monomers form peptides with tertiary structures and potential catalytic functions. The HPLC profile of synthesized oligomers varied with each particular run, but the products were found to separate into distinct clusters when more than one hundred runs were compared statistically. This observation suggests that chemical evolution on the early Earth had stochastic aspects that must be understood in order to develop useful models of prebiotic evolution.

Alanine↗

PubMed2002

Microdynamic context and macrodynamic data in biological systems.

Dynamics without boundary conditions has been attempted to address an extreme subtlety of what looks like boundary conditions or constraints appeared in the biological realm. Microdynamic context accessible in first- and second-person descriptions in the present progressive tense can precipitate the robust macrodynamic data, that are retroactively couched upon the standard dynamics supplemented by specific boundary conditions framed in third-person descriptions in the present tense. Addressing dynamics in first- and second-person descriptions grounds itself upon the process of measurement internal to any material bodies. Internal measurement comes to provide a material means for naturalizing both consciousness and attentive awareness.

Animals↗

PubMed2002

Prebiotic oligomerization on or inside lipid vesicles in hydrothermal environments.

Oligomerization of amino acids proceeded on or inside lipid vesicles as a model of prebiotic cells in a simulated hydrothermal environment. When the suspension of lipid vesicles taking up monomeric glycine underwent a sudden temperature drop by traversing from a hot (180 degrees C) to a cold (0 degree C) region repeatedly while circulating through a closed reaction circuit, oligopeptides up to heptaglycine were formed even in the absence of condensing agents.

Amino Acids↗

PubMedDate not supplied

Quantum mechanics in first, second and third person descriptions.

Although quantum mechanics in third person descriptions is certainly legitimate insofar as one is sure about what each energy quantum is all about, quantum mechanics in first person descriptions comes to the surface once one raises the issue of how each quantum transforms itself as measuring and interacting with the others of the similar nature. Each energy quantum is taken as the robust confinement of interactions, whose first person descriptions address the quantum involved in the process of measuring other quanta internally. In addition, the issue of how the robust confinement of interactions could come into being and develop is a matter of quantum mechanics in second person descriptions. Biological activities including cell motility and muscle contraction address the issue of quantum coherence accessible in quantum mechanics in second person descriptions.

Narration↗