Oscillating external force as a tool to tune motility characteristics of molecular motors

2021 ◽  
Vol 104 (6) ◽  
Author(s):  
Andreja Šarlah
Keyword(s):  
External Force ◽  
Molecular Motors

Enhanced Diffusion in a Model of Molecular Motors with Potential Switching

2019 ◽  
Vol 18 (02) ◽  
pp. 1940005 ◽  
Author(s):  
Ryota Shinagawa ◽  
Kazuo Sasaki
Keyword(s):  
Diffusion Coefficient ◽  
External Force ◽  
Molecular Motors ◽  
Periodic Potential ◽  
Brownian Particle ◽  
Molecular Motor ◽  
Free Diffusion ◽  
Enhanced Diffusion ◽  
Additional Peak ◽  
Diffusion Enhancement

Diffusion enhancement is a phenomenon in which the diffusion coefficient of a system is increased by an external force and it becomes larger than that of the force-free diffusion in thermal equilibrium. It is known that this phenomenon occurs for a Brownian particle in a periodic potential under a constant external force. Recently, it was found that diffusion enhancement also occurred in a biological molecular motor, whose moving part could move itself by switching the potentials generated by the other parts. It was shown that the diffusion coefficient exhibited peaks as a function of a constant external force. Here, we report the occurrence of an additional peak and investigate the condition governing its appearance.

scholarly journals Acceleration of DNA Replication of Klenow Fragment by Small Resisting Force

2021 ◽  
Vol 38 (11) ◽  
pp. 118701
Author(s):  
Yu-Ru Liu ◽  
Peng-Ye Wang ◽  
Wei Li ◽  
Ping Xie
Keyword(s):  
Dna Replication ◽  
External Force ◽  
Single Molecule ◽  
Molecular Motors ◽  
Dna Polymerases ◽  
Maximum Velocity ◽  
Magnetic Tweezers ◽  
Coupling Mechanism ◽  
Klenow Fragment ◽  
Chemomechanical Coupling

DNA polymerases are an essential class of enzymes or molecular motors that catalyze processive DNA syntheses during DNA replications. A critical issue for DNA polymerases is their molecular mechanism of processive DNA replication. We have proposed a model for chemomechanical coupling of DNA polymerases before, based on which the predicted results have been provided about the dependence of DNA replication velocity upon the external force on Klenow fragment of DNA polymerase I. Here, we performed single molecule measurements of the replication velocity of Klenow fragment under the external force by using magnetic tweezers. The single molecule data verified quantitatively the previous theoretical predictions, which is critical to the chemomechanical coupling mechanism of DNA polymerases. A prominent characteristic for the Klenow fragment is that the replication velocity is independent of the assisting force whereas the velocity increases largely with the increase of the resisting force, attains the maximum velocity at about 3.8 pN and then decreases with the further increase of the resisting force.

Video-microscopic measurement of cell-substratum traction forces generated by locomoting keratocytes

1993 ◽  
Vol 51 ◽  
pp. 188-189
Author(s):  
Tim Oliver ◽  
Michelle Leonard ◽  
Juliet Lee ◽  
Akira Ishihara ◽  
Ken Jacobson
Keyword(s):  
Silicone Rubber ◽  
Molecular Motors ◽  
Video Frame ◽  
Traction Forces ◽  
Cell Traction Forces ◽  
Latex Beads ◽  
Cell Traction ◽  
Local Cell ◽  
Microscopic Measurement ◽  
Kinetics Of

We are using video-enhanced light microscopy to investigate the pattern and magnitude of forces that fish keratocytes exert on flexible silicone rubber substrata. Our goal is a clearer understanding of the way molecular motors acting through the cytoskeleton co-ordinate their efforts into locomotion at cell velocities up to 1 μm/sec. Cell traction forces were previously observed as wrinkles(Fig.l) in strong silicone rubber films by Harris.(l) These forces are now measureable by two independant means.In the first of these assays, weakly crosslinked films are made, into which latex beads have been embedded.(Fig.2) These films report local cell-mediated traction forces as bead displacements in the plane of the film(Fig.3), which recover when the applied force is released. Calibrated flexible glass microneedles are then used to reproduce the translation of individual beads. We estimate the force required to distort these films to be 0.5 mdyne/μm of bead movement. Video-frame analysis of bead trajectories is providing data on the relative localisation, dissipation and kinetics of traction forces.

The Unassailable Self: Freud's Image Among Post-war American Intellectuals

2017 ◽  
Vol 19 (1) ◽  
pp. 55-75 ◽  
Author(s):  
Katherine Jenness
Keyword(s):  
World War Ii ◽  
Cold War ◽  
External Force ◽  
Sigmund Freud ◽  
Human Being ◽  
World War ◽  
The Us ◽  
Post War ◽  
The Cold War ◽  
The Way

This paper explores the way American intellectuals depicted Sigmund Freud during the peak of popularity and prestige of psychoanalysis in the US, roughly the decade and a half following World War II. These intellectuals insisted upon the unassailability of Freud's mind and personality. He was depicted as unsusceptible to any external force or influence, a trait which was thought to account for Freud's admirable comportment as a scientist, colleague and human being. This post-war image of Freud was shaped in part by the Cold War anxiety that modern individuality was imperilled by totalitarian forces, which could only be resisted by the most rugged of selves. It was also shaped by the unique situation of the intellectuals themselves, who were eager to position themselves, like the Freud they imagined, as steadfastly independent and critical thinkers who would, through the very clarity of their thought, lead America to a more robust democracy.

Properties of turbulence driven by random external force in the Burgers model

2016 ◽  
Vol 186 (12) ◽  
pp. 1349-1353
Author(s):  
Kirill P. Zybin ◽  
Anton S. Il'yn
Keyword(s):  
External Force ◽  
Burgers Model
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