DYNAMICAL BEHAVIORS OF COULOMB CRYSTALS AND LIQUIDS IN STRONGLY COUPLED DUSTY PLASMAS(Session II : Chaos, The 1st Tohwa University International Meeting on Statistical Physics Theories, Experiments and Computer Simulations)

この論文は国立情報学研究所の電子図書館事業により電子化されました。We experimentally study the microscopic dynamical behaviors of the strongly coupled dusty plasma with SiO_2 suspensions in low pressure rf Ar discharge through optically tracing the trajectories of particles. As rf power increases, the large scale cooperative domain motion and rotation, cyclic hopping, defect motion and interaction, and diffusive type motion are excited and observed

Relaxation of DNA on a supported lipid membrane

We utilize real-time single-molecule imaging to investigate the transient response of DNA molecules on a rigidly supported lipid membrane upon their adsorptions. Following the stochastic landing onto the membrane at a nearly spherical initial state, these DNA coils gradually relax and expand their apparent size (R2g,xy) in a highly anisotropic fashion. The evolution of R2g,xy exhibits considerable variations among individual molecules, and its time dependence can be characterized by a generic exponential relaxation, but only after a statistical averaging over a large number of events. This evolution defines the primary relaxation timescale, which varies with the lipid composition of the membrane. The statistics and time-resolved analyses of the conformation of individual DNA coils further indicate that the interaction between the absorbing molecules and the lipid elements plays an important role in the relaxation towards the final equilibrium of this polymer-membrane complex

Anomalous diffusion of DNA on a supported cationic lipid membrane

We used fluorescence microscopy to investigate the diffusion dynamics of individual DNA molecules on supported cationic lipid membranes. The mean-squared displacement of DNA on the membrane surface showed sub-diffusion associated with a slower DNA conformational relaxation at a short time scale. The evolution of contours of these non-entangled DNA at this short time scale was retained within a “hypothetical tube” of diameter $<1\ \mu \text{m}$ . Inhomogeneous DNA-surface interaction along the DNA contour, identified by total internal reflection fluorescence microscopy, suggested a mechanism for the anomalous dynamics of DNA on the membrane

The Chicken Frizzle Feather Is Due to an α-Keratin (<i>KRT75</i>) Mutation That Causes a Defective Rachis

Feathers have complex forms and are an excellent model to study the development and evolution of morphologies. Existing chicken feather mutants are especially useful for identifying genetic determinants of feather formation. This study focused on the gene F, underlying the frizzle feather trait that has a characteristic curled feather rachis and barbs in domestic chickens. Our developmental biology studies identified defects in feather medulla formation, and physical studies revealed that the frizzle feather curls in a stepwise manner. The frizzle gene is transmitted in an autosomal incomplete dominant mode. A whole-genome linkage scan of five pedigrees with 2678 SNPs revealed association of the frizzle locus with a keratin gene-enriched region within the linkage group E22C19W28_E50C23. Sequence analyses of the keratin gene cluster identified a 69 bp in-frame deletion in a conserved region of KRT75, an α-keratin gene. Retroviral-mediated expression of the mutated F cDNA in the wild-type rectrix qualitatively changed the bending of the rachis with some features of frizzle feathers including irregular kinks, severe bending near their distal ends, and substantially higher variations among samples in comparison to normal feathers. These results confirmed KRT75 as the F gene. This study demonstrates the potential of our approach for identifying genetic determinants of feather forms.</p

The Chicken Frizzle Feather Is Due to an α-Keratin (<em>KRT75</em>) Mutation That Causes a Defective Rachis

<div><p>Feathers have complex forms and are an excellent model to study the development and evolution of morphologies. Existing chicken feather mutants are especially useful for identifying genetic determinants of feather formation. This study focused on the gene <em>F</em>, underlying the frizzle feather trait that has a characteristic curled feather rachis and barbs in domestic chickens. Our developmental biology studies identified defects in feather medulla formation, and physical studies revealed that the frizzle feather curls in a stepwise manner. The frizzle gene is transmitted in an autosomal incomplete dominant mode. A whole-genome linkage scan of five pedigrees with 2678 SNPs revealed association of the frizzle locus with a keratin gene-enriched region within the linkage group E22C19W28_E50C23. Sequence analyses of the keratin gene cluster identified a 69 bp in-frame deletion in a conserved region of <em>KRT75</em>, an α-keratin gene. Retroviral-mediated expression of the mutated <em>F</em> cDNA in the wild-type rectrix qualitatively changed the bending of the rachis with some features of frizzle feathers including irregular kinks, severe bending near their distal ends, and substantially higher variations among samples in comparison to normal feathers. These results confirmed <em>KRT75</em> as the <em>F</em> gene. This study demonstrates the potential of our approach for identifying genetic determinants of feather forms.</p> </div

Contrast between feathers that have misexpressed GFP (Control, right wing) and KRT75-MT (left wing).

<p>(A) Images of flight feathers from both sides of the chicken (the R<i>n</i> and L<i>n</i> denote the <i>n</i>^th feather taken from the right and left wing, respectively). (B) Effects of the viral misexpression, as shown by the qualitative change of the curves of θ(<i>s</i>) from the controls. Without the gene mutation, the trend of curves θ(<i>s</i>) obtained from opposite sides of a normal chicken were expected to exhibit mirror symmetry, which is obviously abrogated in this case.</p