Protein fluid shear stress

Chachisvilis, M., Zhang, Y. L. and Frangos, J. A. (2006). G protein-coupled receptors sense fluid shear stress in endothelial cells. Proc. Natl. Acad. Sci. USA 103, 15463-8. 

Osteoblasts subjected to fluid shear increase expression of the early response gene, c-fos, and the inducible isoform of cyclooxygenase, COX-2, two proteins linked to anabolic response of bone to mechanical stimulation. Flow-induced responses in osteoblasts are mediated by inositol triphosphate intracellular calcium release. Flow-mediated stress is reported to induce both PGE2 and NO production. Fluid shear stress stimulates NO release by two distinct pathways a G-protein and calcium-dependent phase sensitive to flow gradients, and a G-protein and calcium-independent pathway stimulated by sustained flow. 

Li S, Kim M, Hu YL, Jalai S, Schlaepfer DD, Hunter T, Chien S, Shyy JY. Fluid shear stress activation of focal adhesion kinase. Linking to mitogen-activated protein kinases. / Biol Chem. 1997 272 30455-30462. 

Archer, S. L., Huang, J. M. C., HampI, V., Nelson, D. P., Shultz, P. J., and Weir, E. K. (1994). Nitric oxide and cGMP cause vasorelaxation by activation of a charybdotoxin-sensitive K channel by cGMP-dependent protein kinase. Proc. Natl. Acad. Set. U.S.A. 91,7583-7587. Beckman, J. S., Ye, Y. Z., Anderson, P. G., Chen, J., Accavitti, M. A., Tarpey, M. M., and White, C. R. (1994). Extensive nitration of protein tyrosines in human atherosclerosis detected by immunohistochemistry. Biol. Chem. Hoppe-Seyler 375, 81-88. Bhagyalakshmi, A., Berthiaume, F., Reich, K. M., and Frangos, J. A. (1992). Fluid shear stress stimulates membrane phospholipid metabolism in cultured human endothelial cells. J. Vase. Res. 29, 443-449. 

Shyy, Y.-J., Hsieh, H.-J., Usami, S., and Chien, S. (1994). Fluid shear stress induces a biphasic response of human monocyte chemotactic protein 1 gene expression in vascular endothelium. Proc. Natl. Acad. Sci. U.S.A. 91, 4678-4682. 

Berk, B.C. et al.. Protein kinases as mediators of fluid shear stress stimulated signal transduction in endothelial cells a hypothesis for calcium-dependent and calcium-independent events activated by flow, /. Biomech., 28,1439,1995. 

Yu, H., Zeng, Y., Hu, J., and Li, C. Fluid shear stress induces the secretion of monocyte chemoattractant protein-1 in cultured human umbilical vein endothelial cells. Clin Hemorheol Microcirc 26 199-207,2002. 

In this volume not all stress types are treated. Various aspects have been reviewed recently by various authors e.g. The effects of oxygen on recombinant protein expression by Konz et al. [2]. The Mechanisms by which bacterial cells respond to pH was considered in a Symposium in 1999 [3] and solvent effects were reviewed by de Bont in the article Solvent-tolerant bacteria in biocatalysis [4]. Therefore, these aspects are not considered in this volume. Influence of fluid dynamical stresses on micro-organism, animal and plant cells are in center of interest in this volume. In chapter 2, H.-J. Henzler discusses the quantitative evaluation of fluid dynamical stresses in various type of reactors with different methods based on investigations performed on laboratory an pilot plant scales. S. S. Yim and A. Shamlou give a general review on the effects of fluid dynamical and mechanical stresses on micro-organisms and bio-polymers in chapter 3. G. Ketzmer describes the effects of shear stress on adherent cells in chapter 4. Finally, in chapter 5, P. Kieran considers the influence of stress on plant cells. 

The possible development of gradients in the components of the interfacial stress tensor due to flow of an adjacent fluid implies that the momentum flux caused by the the flow of liquid at one side of the interface does not have to be completely transported across the interface to the second fluid but may (partly or completely) be compensated in the interface. The extent to which this is possible depends on the rheological properties of the interface. For small shear stresses the interface may behave elastically or viscoelastically. For an elastic interfacial layer the structure remains coherent the layer will only deform, while for a viscoelastic one it may or may not start to flow. The latter case has been observed for elastic networks (e.g. for proteins) that remciln intact, but inside the meshes of which liquid can flow leading to energy dissipation. At large stresses the structure may yield or fracture (collapse), leading to an increased flow. 

Given the availability of hollow fiber membranes adequately permeable to substrates and products, and the control of fluid flow all around the fibers in the bundle in order to assure uniform flow distribution and to avoid stagnation (in order to reduce mass transfer diffusional resistances), the technique offers several advantages. Enzyme proteins can be easily retained within the core of the fibers with no deactivation due to coupling agents or to shear stresses, and the enzyme solution can be easily recovered and/or recycled. 

The macroscopic rheologic properties of blood are determined by its constituents. At a normal physiological hematocrit of 45 percent, the viscosity of blood is /u, = 4 x 10" dyne s/cm (or poise), which is roughly 4 times that of water. Plasma alone (zero hematocrit) has a viscosity of /u = 1.1 X 10 to 1.6 X 10 poise, depending upon the concentration of plasma proteins. Aftera heavy meal, when the concentration of lipoproteins is hig the plasma viscosity is quite elevated (Whitmore, 1968). In large arteries, the shear stress (t) exerted on blood elements is linear with the rate of shear, and blood behaves as a newtonian fluid, for which. 

Effect of the origin of xanthan samples. Different representative samples of xanthan were tested for their ability to display thixotropic behavior in the suitable conditions determined from the aforementioned results. Following the same procedure, all xanthan samples were dissolved in sea water at pH 8 in the presence of added proteins. The flow curves, i.e stabilized values of shear stress at three shear rates, were determined and are shown in Figure 6. Under these conditions, where the aggregation of xanthan chains was favoured, only xanthan C exhibited thixotropic behavior. The other products had the standard behavior of a pseudoplastic fluid and the shear stress values were identical when the shear rate was increased or decreased. 

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