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M Yano

Publications and source records attributed to M Yano.

At least 739 records · Page 41Linked to original sources
PubMed1978

Studies of the chemo-mechanical conversion in artificially produced streamings. I. Reconstruction of a chemo-mechanical system from acto-HMM of rabbit skeletal muscle.

Steady and uniform streamings (SUS) of HMM solutions were set up in the presence of Mg-ATP in a circular slit, on both side-walls of which a Millipore filter was fixed; F-actin filaments from rabbit skeletal muscle were bound onto the Millipore filter by cyanogen bromide in the flow. The direction of the SUS was specificially determined by that of the flow during the fixing of F-actin and was independent of the direction of the initial velocity applied externally to the HMM solutions. The SUS continued for about 90 min with a velocity of about 20 mum/s at 20 degrees C. There was a strong correlation between the acto-HMM ATPase activity and the velocity of SUS when the salt concentration was varied. Moreover, this was also the case when the ATPase activity was controlled by Ca2+, when native tropomyosin was bound to F-actin in the circular slit. Careful examination led to the conclusions that F-actin filaments are fixed on the Millipore filter with a specific polarity and that a chemo-mechanical system had been successfully reconstituted in our "stream cells," in which chemical energy from ATP is converted to the mechanical energy of streaming.

Actins↗
PubMed1978

Studies of the chemo-mechanical conversion in artificially produced streamings. III. Dynamic cooperativity--a new cooperativity in actomyosin systems with a polarized arrangement of F-actin.

The order--disorder phase transition in the chemo-mechanical process in our streaming system, which was reported in the preceding paper [Yano, M. & Shimizu, H., J. Biochem, 84, 1087--1092], was studied in detail. Starting from the hypothesis that a new type of cooperativity, dynamic cooperativity, is present in the elementary cycles of the chemo-mechanical conversion, quantitative and consistent agreement was obtained between the theoretical and experimental data on the temperature dependences of the streaming velocity and the ATPase activity, including the presence of the phase transition. The hypothesis was also supported by observations of the temperature dependence of the ATPase activity in resisted streaming. The physical and physiological significance of dynamic cooperativity is considered. It is shown that dynamic cooperativity arises in actomyosin system which have a polarized arrangement of F-actin by directed streaming of the solution, because the rate of the elementary cycle can be accelerated by the streaming. Furthermore, dynamic cooperativity is the key mechanism of self-organization of a dynamical order such that in ordered motions, and is one of the essential conditions for the direct conversion of the chemical energy of ATP to the mechanical energy of ordered and directed motion.

Actins↗
PubMed1977

[Caraka Samhita].

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