Title:	Buckling, stiffening, and negative dissipation in the dynamics of a biopolymer in an active medium
Authors:	Kikuchi, Norio Ehrlicher, Allen Koch, Daniel Kas, Josef A. Ramaswamy, Sriram Rao, Madan
Keywords:	cytoskeleton active hydrodynamics microrheology fluctuation-dissipation ratio neuronal growth cone
Issue Date:	24-Nov-2009
Publisher:	National Academy of Sciences
Citation:	Proceedings of the National Academy of Sciences, 2009, Vol.106, p19776
Abstract:	We present a generic theory for the dynamics of a stiff filament under tension, in an active medium with orientational correlations, such as a microtubule in contractile actin. In sharp contrast to the case of a passive medium, we find the filament can stiffen, and possibly oscillate or buckle, depending on both the contractile or tensile nature of the activity and the filament-medium anchoring interaction. We also demonstrate a strong violation of the fluctuation–dissipation (FD) relation in the effective dynamics of the filament, including a negative FD ratio. Our approach is also of relevance to the dynamics of axons, and our model equations bear a remarkable formal similarity to those in recent work [Martin P, Hudspeth AJ, Juelicher F (2001) Proc Natl Acad Sci USA 98:14380–14385] on auditory hair cells. Detailed tests of our predictions can be made by using a single filament in actomyosin extracts or bacterial suspensions.
Description:	Restricted Access.
URI:	http://hdl.handle.net/2289/3937
ISSN:	0027-8424 1091-6490 (Online)
Alternative Location:	http://dx.doi.org/10.1073/pnas.0900451106
Copyright:	2009 National Academy of Sciences
Appears in Collections:	Research Papers (TP)

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