Stress responses, networks

Cabusora L, Sutton E, Eulmer A, Eorst CV. Differential network expression during drug and stress response. Bioinformatics 2005 21 2898-905. 

The assemblage of chains is constructed to represent the affine network model of rubber elasticity in which all network junction positions are subject to the same affine transformation that characterizes the macroscopic deformation. In the affine network model, junction fluctuations are not permitted so the model is simply equivalent to a set of chains whose end-to-end vectors are subject to the same affine transformation. All atoms are subject to nonbonded interactions in the absence of these interactions, the stress response of this model is the same as that of the ideal affine network. 

J.H. Crowe, in Molecular Aspects of the Stress Response Chaperones, Membranes and Networks, ed. by P. Csermely, L. Vfgh (Landes Bioscience and Springer, New York, 2007), Chapter 13... 

Homeostatic signaling networks regulating pollen tube growth converge with those regulating cell volume during osmotic stress responses... 

Shinozaki, K., Yamaguchi-Shinozaki, K., and Seki, M., 2003, Regulatory network of gene expression in the drought and cold stress responses. Curr. Opin. Plant Biol. 6 410—417. 

Csermely P, Vigh L, eds. Molecular aspects of tiie stress response chaperones, membranes and networks 2007. Advances in experimental medicine and biology. Landes Bioscience and Springer Science + Business Media, LLC, New York. 

Remember that a viscoelastic flnid has two components related to y by Eq. 6.1 and y by Eq. 6.2. Erom Eq. 6.5, it is clear that for such dynamic oscillatory displacement, the measnred stress response has two components an in-phase component (sincot) and an ont-of-phase component (coscot). Viscoelastic materials prodnce this two-component stress response when they undergo mechanical deformation becanse some of the energy is stored elastically and some is dissipated or lost. The stress response, which is in-phase with the mechanical displacement, defines a storage or elastic modulus, G, and the out-of-phase stress response defines a loss or viscous modulus, G"". The storage modulus (G ) provides information about the fluid s elasticity and network structure. 

Through use of classical network theories of macromolecules, G has been shown to be proportional to crosslink density by G = nKT -i- Gen, where n is the nnmber density of crosslinkers, K is the Boltzmann s constant, T is the absolnte temperature, and Gen is the contribution to the modulus because of polymer chain entanglement (Knoll and Prud Homme, 1987). The loss modulus (G") gives information abont the viscous properties of the fluid. The stress response for a viscous Newtonian fluid would be 90 degrees out-of-phase with the displacement but in-phase with the shear rate. So, for an elastic material, all the information is in the storage modulus, G, and for a viscous material, aU the information is in the loss modulus, G". Refer to Eigure 6.2, the dynamic viscosities p and iT are defined as... 

Chen, W.J., and T. Zhu. 2004. Networks of transcription factors with roles in environmental stress response. Trends Plant Sci. 9 592-596. 

Fujita, M., Y. Fujita, Y. Noutoshi, et al. 2006. Crosstalk between abiotic and biotic stress responses a current view from the points of convergence in the stress signaling networks. Curr. Opin. Plant Biol. 9 436 42. 

These differences are shown in the following examples where measurements of the dynamic moduli, G and G" are used to monitor the structure of gel networks. Measurements are performed by imposing an oscillatory shear field on the material and measuring the oscillatory stress response. The stress is decomposed into a component in phase with the displacement (which defines the storage modulus G ) and a component 90 out of phase (which defines the loss modulus G"). The value of G indicates the elastic and network structure in the system (15, 17, 18) and can be interpreted by using polymer kinetic theories. 

Miinster S, Jawerth LM, Leslie BA et al (2013) Strain history dependence of the nonlinear stress response of fibrin and collagen networks. Proc Natl Acad Sci USA 110 12197-12202... 

---