All-electrical switching and control mechanism for actomyosin-powered nanoactuators

Mihajlović, Goran; Brunet, Nicolas M.; Trbovic, Jelena; Xiong, Peng; Molnár, S. von; Chase, P. Bryant

doi:10.1063/1.1777815

Cited by 38 publications

(42 citation statements)

References 25 publications

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“…Recorded images of RhPh-labeled F-actin motility were digitized, and analysis of filament sliding speed (V f) was carried out with the aid of MetaMorph software (Universal Imaging; Molecular Devices, Downingtown, PA), as described previously (28). For each flow cell, 12 stacks of frames were created from the digitized recordings; each stack consisted of 30 (1 s of recorded data) or 90 frames (3 s of recorded data) of motility data.…”

Section: Methodsmentioning

confidence: 99%

Contractile properties of muscle fibers from the deep and superficial digital flexors of horses

Butcher

Chase

Hermanson

et al. 2010

American Journal of Physiology-Regulatory, Integrative and Comp

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11, 2010; doi:10.1152/ajpregu.00510.2009.-Equine digital flexor muscles have independent tendons but a nearly identical mechanical relationship to the main joint they act upon. Yet these muscles have remarkable diversity in architecture, ranging from long, unipennate fibers ("short" compartment of DDF) to very short, multipennate fibers (SDF). To investigate the functional relevance of the form of the digital flexor muscles, fiber contractile properties were analyzed in the context of architecture differences and in vivo function during locomotion. Myosin heavy chain (MHC) isoform fiber type was studied, and in vitro motility assays were used to measure actin filament sliding velocity (Vf). Skinned fiber contractile properties [isometric tension (P0/CSA), velocity of unloaded shortening (VUS), and forceCa 2ϩ relationships] at both 10 and 30°C were characterized. Contractile properties were correlated with MHC isoform and their respective Vf. The DDF contained a higher percentage of MHC-2A fibers with myosin (heavy meromyosin) and Vf that was twofold faster than SDF. At 30°C, P0/CSA was higher for DDF (103.5 Ϯ 8.75 mN/mm 2 ) than SDF fibers (81.8 Ϯ 7.71 mN/mm 2 ). Similarly, VUS (pCa 5, 30°C) was faster for DDF (2.43 Ϯ 0.53 FL/s) than SDF fibers (1.20 Ϯ 0.22 FL/s). Active isometric tension increased with increasing Ca 2ϩ concentration, with maximal Ca 2ϩ activation at pCa 5 at each temperature in fibers from each muscle. In general, the collective properties of DDF and SDF were consistent with fiber MHC isoform composition, muscle architecture, and the respective functional roles of the two muscles in locomotion. myosin; deep digital flexor; superficial digital flexor THE DIGITAL FLEXORS OF THE EQUINE FORELIMB provide a unique opportunity to investigate the integration of molecular composition, architectural organization, and functional utilization of locomotor muscles in a large cursorial mammal. Although their tendons have essentially equivalent relationships to the main joint they act upon, the metacarpophalangeal joint (fetlock) of the distal limb, they show remarkable diversity in their muscle architecture. The "short" (humeral) compartment of the deep digital flexor (DDF) has long, unipennate fibers, whereas the superficial digital flexor (SDF) has short, multipennate fibers (8,20,54). Muscle architecture is an important component of musculoskeletal structure and function. For example, a shortfibered muscle with a long, compliant tendon suggests a capacity for substantial elastic energy storage, an effective means to reduce metabolic cost in locomotion (1). Recent interest in understanding how architecture of the equine digital flexors relates to their function in the distal limb during locomotion has led to in vivo studies examining 1) isometric force production for characterization of the passive and active force properties of DDF and SDF muscles (47) and 2) DDF and SDF contractile behavior and muscle-tendon unit function during walking and running (9, 10). General findings from these studies indicate th...

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Section: Methodsmentioning

confidence: 99%

Contractile properties of muscle fibers from the deep and superficial digital flexors of horses

Butcher

Chase

Hermanson

et al. 2010

American Journal of Physiology-Regulatory, Integrative and Comp

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“…[1][2][3][4][5][6][7] Temperature increase has been reported to influence the structure stability, 2,3,6 the working quality of the core/shell bionanoactuators, 7 and light emission of CdSe/ CdS nanocrystals. 1 The melting point of the coated nanocores can be modified by the technique of surface coating, in which lower melting point [6][7][8] and superheating and supercooling 5 have been achieved. Extremely high inner stress 4,6 was generated to induce more transformations in the heated coated structures.…”

mentioning

confidence: 99%

Nanojets from the heated PbO-coated Pb clusters and its ambient sensitivity

Song

Han

et al. 2006

Applied Physics Letters

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The thermal stability of the PbO-coated Pb nanoclusters was evaluated in different ambient pressures by the temperature-variable Raman scattering and transmission electron microscopy. The change of the inner pressure was presented by Raman scattering to demonstrate the cell’s collapse with the final formation of the liquid nanojets. The different ambient pressures were used to tune the working of the nanojet from no jet production to multiple jets. An interpretation of gas-participated cooling that improves the working stability of the nanonozzles was proposed. The ambient-sensitive working stability was suggested to be a universal effect for the few-atom-contained nanodevices.

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“…IVM methods were essentially as described (Chase et al, 2000;Mihajlović et al, 2004;Schoffstall et al, 2006a). Rabbit skeletal or porcine cardiac F-actin was fluorescently labeled with rhodamine phalloidin (RhPh).…”

Section: Ivm Assaysmentioning

confidence: 99%

Interaction Between Troponin and Myosin Enhances Contractile Activity of Myosin in Cardiac Muscle

Schoffstall

LaBarbera

Brunet

et al. 2011

DNA and Cell Biology

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Ca2þ signaling in striated muscle cells is critically dependent upon thin filament proteins tropomyosin (Tm) and troponin (Tn) to regulate mechanical output. Using in vitro measurements of contractility, we demonstrate that even in the absence of actin and Tm, human cardiac Tn (cTn) enhances heavy meromyosin MgATPase activity by up to 2.5-fold in solution. In addition, cTn without Tm significantly increases, or superactivates sliding speed of filamentous actin (F-actin) in skeletal motility assays by at least 12%, depending upon [cTn]. cTn alone enhances skeletal heavy meromyosin's MgATPase in a concentration-dependent manner and with submicromolar affinity. cTn-mediated increases in myosin ATPase may be the cause of superactivation of maximum Ca 2þ -activated regulated thin filament sliding speed in motility assays relative to unregulated skeletal F-actin. To specifically relate this classical superactivation to cardiac muscle, we demonstrate the same response using motility assays where only cardiac proteins were used, where regulated cardiac thin filament sliding speeds with cardiac myosin are >50% faster than unregulated cardiac F-actin. We additionally demonstrate that the COOHterminal mobile domain of cTnI is not required for this interaction or functional enhancement of myosin activity. Our results provide strong evidence that the interaction between cTn and myosin is responsible for enhancement of cross-bridge kinetics when myosin binds in the vicinity of Tn on thin filaments. These data imply a novel and functionally significant molecular interaction that may provide new insights into Ca 2þ activation in cardiac muscle cells.

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All-electrical switching and control mechanism for actomyosin-powered nanoactuators

Cited by 38 publications

References 25 publications

Contractile properties of muscle fibers from the deep and superficial digital flexors of horses

Contractile properties of muscle fibers from the deep and superficial digital flexors of horses

Nanojets from the heated PbO-coated Pb clusters and its ambient sensitivity

Interaction Between Troponin and Myosin Enhances Contractile Activity of Myosin in Cardiac Muscle

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