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Elastically coupled molecular motors 总被引:3,自引:0,他引:3
A. Vilfan E. Frey F. Schwabl 《The European Physical Journal B - Condensed Matter and Complex Systems》1998,3(4):535-546
We study the influence of filament elasticity on the motion of collective molecular motors. It is found that for a backbone
flexibility exceeding a characteristic value (motor stiffness divided through the mean displacement between attached motors),
the ability of motors to produce force reduces as compared to rigidly coupled motors, while the maximum velocity remains unchanged.
The force-velocity-relation in two different analytic approximations is calculated and compared with Monte-Carlo simulations.
Finally, we extend our model by introducing motors with a strain-dependent detachment rate. A remarkable crossover from the
nearly hyperbolic shape of the Hill curve for stiff backbones to a linear force-velocity relation for very elastic backbones
is found. With realistic model parameters we show that the backbone flexibility plays no role under physiological conditions
in muscles, but it should be observable in certain in vitro assays.
Received: 27 November 1997 / Revised: 20 February 1998 / Accepted: 27 March 1998 相似文献
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Summary Two procedures aimed at a synthetic, quantitative characterization of the integrative activity in a small system of nerve
cells are proposed, and applications to the buccal ganglion of the molluskAplysia are described. Both methods are based on cross-correlation evaluation. The first method processes intracellular signals simultaneously
recorded from pairs of neurones, and reveals and measures the occurrence of shared synaptic input. The second method processes
extracellular multiunit signals recorded by two cuff electrodes placed around one nerve, and evaluates the impulse traffic,
subdivided according to direction and speed of propagation. The outcome of both methods may be used to represent the state
of the system, and may provide a basis to further studies on its dynamics.
Paper presented at the International Workshop ?Fluctuations in Physics and Biology: Stochastic Resonance, Signal Processing
and Related Phenomena?, Elba, 5–10 June 1994. 相似文献
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To put more information into a difference scheme of a differential equation for making an accurate prediction, a new kind
of time integration scheme, known as the retrospective (RT) scheme, is proposed on the basis of the memorial dynamics. Stability
criteria of the scheme for an advection equation in certain conditions are derived mathematically. The computations for the
advection equation have been conducted with its RT scheme. It is shown that the accuracy of the scheme is much higher than
that of the leapfrog (LF) difference scheme.
The project supported by the National Key Program for Developing Basic Sciences (G1999043408 and G1998040901-1) and the National
Natural Sciences Foundation of China (40175024 and 40035010) 相似文献
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Summary In the retina of the turtle, prolonged illumination of the receptive field surrond can lead to the appearance of sustained
oscillatory responses in horizontal cells. In most cells the oscillations consist of a main component of 40–50 Hz frequency
modulated by slower waves. The experimental evidence suggests that these responses are due to the activation of the feeback
circuit linking cone photoreceptors and horizontal cells in the vertebrate retina.
Paper presented at the International Workshop ?Fluctuations in Physics and Biology: Stochastic Resonance, Signal Processing
and Related Phenomena?, Elba, 5–10 June 1994. 相似文献
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