Clamp cell

Kong, X-P, R. Onrust, M. O Donnell, and J. Kuriyan, Three-dimensional structure of the /3 subunit of E. coli DNA polymerase HI holoenzyme A sliding clamp. Cell 69 425-437, 1992. 

A comparison of the coefficient of variation between the screw-type cells described by Bronaugh (3) and the modified spring clamped cells shows that there does appear to be a slight reduction in variability using the spring clamped diffusion cell. However, there is no statistical difference between the two types of diffusion cells (p>0.5). 

Zeta potential measurements. The zeta potential f of the sample surfaces was determined by the streaming potential method, using a clamping cell connected with an EKA electrokinetic analyzer (Anton Paar GmbH, Graz, Austria). In this cell the sample is pressed against a PMMA spacer with seven channels. The measurements were performed with a KC1 electrolyte solution (10-3 M, 500 mL). The pH was adjusted to about 10 by adding NaOH (0.1 M,... 

The potential of the samples obtained using the Clamping Cell is no absolute value since the grooved PMMA spacer of the measuring cell contributes one measured surface while the other is the sample surface. Any-... 

In heart, muscarinic receptors inhibit adenylyl cyclase, via activation of PTX-sensitive G (35,80,81,136,137). However, K+ channel opening in response to muscarinic stimulation is not the result of decreased levels of cAMP [138,139], Evidence obtained using patch-clamped cells [160] argues against involvement of any second messenger at all [141-143] in regulation of the K+ channel. Moreover, experiments with inside-out patches demonstrate unequivocally that K+ channels couple directly to a receptor-regulated G protein [144,145], We call this functionally identified G protein Gk. 

X.P. Kong, R. Onrust, M. OdonneU, J. Ktuiyan, 3-Dimensional Structure of the p Subunit of Escherichia coli DNA Polymerase-111 Holoenzyme - A Sliding DNA Clamp , Cell, 69,425(1992)... 

Walker, S.L. et al.. A novel asymmetric clamping cell for measuring streaming potential of flat surfaces, Langmuir, 18, 2193, 2002. 

Stukenberg P. T., Turner J., O Donnell M. (1994) An explanation for lagging strand replication Polymerase hopping among DNA sliding clamps. Cell 78 877. 

FIGURE 10.7 The dimer of 3-subunits of DNA polymerase III bound to DNA. One monomer is shown in yellow, the other in red. Note that the dimer forms a closed loop around the DNA (shown in blue). The rest of the polymerase III holoenzyme is not shown. The remainder of the holoenzyme consists of the core enzyme responsible for the polymerization and the 3 exonuclease activity (ot-, e-, and 0-subunits) and the y-complex (consisting of y-, 5-, 5, X t and /-subunits), which allows the 3-sub-units to form a clamp that surrounds the DNA and slides along it as polymerization proceeds. [Adapted from Kong, X. P., etal Three-Dimensional Structure of the Subunit ofE. Coli DNA Polymerase Holoenzyme A Sliding DNA Clamp. Cell 69, 425-437 (1992).]... 

Edwards, F. A. and Konnerth, A. (1992) Patch-clamping cells in sliced tissue preparations. Methods Enzymol. 207, 208-222. 

Logarithmically varying concentration gradients have also been used for pharmacological testing on patch-clamped cells. 

FIG. 18—Environmental chambers for CF in electrolytes where (a) the CT specimen is loaded horizontally and dipped Into solution [4], and (b) the CT crack is enclosed by a clamped cell and polarized potentiostatically. In part b load (P)-displacement (A) data are recorded by computer and autographically for compliance measurement of crack length and Ki. 

In a new approach, zeta potential measurements were carried out on drip-coated microscope slides using a SurPASS electrokinetic analyzer and clamping cell (Anton PAAR). Each run consisted of a forward and backward pumping cycle taking 15 minutes. Three runs ( 45 minutes) provided a much more demanding test of stability in dilute polyelectrolyte (10 M KBr) compared to the capillary method used previously ( 2 minutes) [108]. Zeta potentials for polymer coatings are known to be affected by pH [113] initial measurements reported here were carried out at pH 7. 

The above combined device with vailing flow rate and simultaneously varying solute concentration helps to control the transport of molecules toward and away from the cells of interest. Embryonic stem cells, for example, are particularly sensitive to their microenvironment. Logarithmically varying concentration gradients have also been used for pharmacological testing on patch-clamped cells. 

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