scholarly journals The influence of poly(ethylene glycol) 6000 on the properties of skeletal-muscle actin

1983 ◽  
Vol 213 (3) ◽  
pp. 651-659 ◽  
Author(s):  
R L Tellam ◽  
M J Sculley ◽  
L W Nichol ◽  
P R Wills
Keyword(s):  
Skeletal Muscle ◽  
Ethylene Glycol ◽  
Actin Polymerization ◽  
Excluded Volume ◽  
Muscle Actin ◽  
Actin Monomer ◽  
Poly Ethylene Glycol ◽  
Fluorescence Measurements ◽  
Volume Increment ◽  
Poly Ethylene

Poly(ethylene glycol) 6000 affected many of the properties of skeletal-muscle actin. It accelerated the rate and increased the extent of actin polymerization as measured by light-scattering and sedimentation studies respectively. Moreover, intrinsic-fluorescence measurements showed that addition of poly(ethylene glycol) 6000 decreased the rate of EDTA-induced denaturation of actin monomer and increased the temperature at which irreversible conformational changes occur in actin monomer. These effects occurred without any apparent direct binding interaction and are postulated to be a consequence of the effect of excluded volume on the thermodynamic activity of actin. A relationship based on spherical geometry was formulated which described the co-volume increment that occurs upon addition of a monomer to a long linear polymer in the presence of a space-filling macromolecule. The application of this relationship to the poly(ethylene glycol) 6000-actin system was not without assumption, but it permitted quantitative estimation of the co-volume increment which proved to be of the sign and magnitude required to explain the increased extent of actin polymerization found experimentally in the presence of various concentrations of poly(ethylene glycol) 6000. It is suggested that, in vivo, excluded volume may play a role in actin-filament formation and in the maintenance of the native G-actin structure.

scholarly journals Controlling Fluid Diffusion and Release through Mixed-Molecular-Weight Poly(ethylene) Glycol Diacrylate (PEGDA) Hydrogels

Materials ◽  
2019 ◽  
Vol 12 (20) ◽  
pp. 3381 ◽  
Author(s):  
Kieran O’Donnell ◽  
Adrian Boyd ◽  
Brian J. Meenan
Keyword(s):  
Tissue Engineering ◽  
Molecular Weight ◽  
Ethylene Glycol ◽  
Mesh Size ◽  
Material Structure ◽  
Poly Ethylene Glycol ◽  
Glycol Diacrylate ◽  
Fluorescence Measurements ◽  
Fluid Permeability ◽  
Poly Ethylene

Due to their inherent ability to swell in the presence of aqueous solutions, hydrogels offer a means for the delivery of therapeutic agents in a range of applications. In the context of designing functional tissue-engineering scaffolds, their role in providing for the diffusion of nutrients to cells is of specific interest. In particular, the facility to provide such nutrients over a prolonged period within the core of a 3D scaffold is a critical consideration for the prevention of cell death and associated tissue-scaffold failure. The work reported here seeks to address this issue via fabrication of hybrid 3D scaffolds with a component fabricated from mixed-molecular-weight hydrogel formulations capable of storing and releasing nutrient solutions over a predetermined time period. To this end, poly(ethylene) glycol diacrylate hydrogel blends comprising mixtures of PEGDA-575 Mw and PEGDA-2000 Mw were prepared via UV polymerization. The effects of addition of the higher-molecular-weight component and the associated photoinitiator concentration on mesh size and corresponding fluid permeability have been investigated by diffusion and release measurements using a Theophylline as an aqueous nutrient model solution. Fluid permeability across the hydrogel films has also been determined using a Rhodamine B solution and associated fluorescence measurements. The results indicate that addition of PEGDA-2000 Mw to PEGDA-575 Mw coupled with the use of a specific photoinitiator concentration provides a means to change mesh size in a hydrogel network while still retaining an overall microporous material structure. The range of mesh sizes created and their distribution in a 3D construct provides for the conditions required for a more prolonged nutrient release profile for tissue-engineering applications.

scholarly journals A Mammalian Actin Substitution in Yeast Actin (H372R) Causes a Suppressible Mitochondria/Vacuole Phenotype

2005 ◽  
Vol 280 (43) ◽  
pp. 36494-36501 ◽  
Author(s):  
Melissa McKane ◽  
Kuo-Kuang Wen ◽  
Istvan R. Boldogh ◽  
Sharmilee Ramcharan ◽  
Liza A. Pon ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Skeletal Muscle ◽  
Structural Analysis ◽  
Sole Carbon Source ◽  
Actin Polymerization ◽  
Muscle Actin ◽  
Actin Monomer ◽  
Wild Type ◽  
Allosteric Communication ◽  
Related Proteins

To determine the reason for the inviability of Saccharomyces cerevisiae with skeletal muscle actin, we introduced into yeast actin the first variant muscle residue from the C-terminal end, H372R. Arg is also found at this position in non-yeast nonmuscle actins. The substitution caused retarded growth on glucose and an inability to use glycerol as a sole carbon source. The mitochondria were clumped and had lost their DNA, the vacuole appeared hypervesiculated, and the actin cytoskeleton became somewhat depolarized. Introduction of the second muscle actin-specific substitution, S365A, rescued these defects. Suppression was also achieved by introducing the four acidic N-terminal residues of muscle actin in place of the two found in yeast actin. The H372R substitution results in an increase in polymerization-dependent fluorescence of Cys-374 pyrene-labeled actin. H372R actin polymerizes slightly faster than wild-type (WT) actin. Yeast actin-related proteins 2 and 3 (Arp2/3) accelerates the polymerization of H372R actin to a much greater extent than WT actin. The two suppressors did not affect the rate of H372R actin polymerization in the absence of an Arp2/3 complex. In contrast, the S365A substitution dampened the rate of Arp2/3 complex-stimulated H372R actin polymerization, and the addition of the four acidic N-terminal residues caused this rate to decrease below that observed with WT actin in the presence of Arp2/3. Structural analysis of the mutations suggests the presence of stringent steric and ionic requirements for the bottom of actin subdomain 1 and also suggests that there is allosteric communication through subdomain 1 within the actin monomer between the N and C termini.

Electrostatic and Excluded Volume Effects on the Transport of Electrolytes in Poly(ethylene glycol)−Water “Mixed Solvents”

2003 ◽  
Vol 107 (44) ◽  
pp. 12363-12369 ◽  
Author(s):  
Fabio Capuano ◽  
Alessandro Vergara ◽  
Luigi Paduano ◽  
Onofrio Annunziata ◽  
Roberto Sartorio
Keyword(s):  
Ethylene Glycol ◽  
Mixed Solvents ◽  
Excluded Volume ◽  
Poly Ethylene Glycol ◽  
Excluded Volume Effects ◽  
Poly Ethylene ◽  
Volume Effects

PIEZOELECTRIC PROPERTIES OF POLY(3-HYDROXYBUTYRATE-CO-3-HEDROXYBUTYRATE)-CO-POLY(ETHYLENE GLYCOL) PRODUCED BY CONTROLLED MICROBIOLOGICAL BIOSYNTHESIS

2019 ◽  
Vol 10 (10) ◽  
Author(s):  
Anton Bonartsev ◽  
Vera Voinova ◽  
Elizaveta Akoulina ◽  
Andrey Dudun ◽  
Irina Zharkova ◽  
...  
Keyword(s):  
Ethylene Glycol ◽  
Piezoelectric Properties ◽  
Poly Ethylene Glycol ◽  
Poly Ethylene
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