Imaging Membrane Transport Processes

Work in this area has focused on the use of polymer-based porous membranes that are used for a variety of separation processes. In the transport studies described herein, the membrane functions as a separator between a donor (containing the species of interest) and a receptor compartment. Transport across the membrane can occur via diffusion, migration, or convection, although using SECM-AFM only the first two transport modes have been studied. 

---

Figure 3. Microfluidic Device. (A) Time lapse illustrating repulsion the ejection of 1.9 pm fluorescent polystyrene microsphere particles from an electroactive microwell. After dissolution of the membrane, the fluorescent particles can be seen in the well. White hnes outline the gold electrodes features. Images are taken every 2 s (total of 10 s). (B) Schematic of the electroactive microwell drug delivery system developed here. Scale bar represents 2 mm. (C) Micro fluidic device with electrical leads connected to thin copper wires. Inset Magnified view of microchip from above looking at the region near the membrane. (D) To illustrate the electrokinetic transport processes involved in the ejection stage, a finite element analysis of time-dependent species transport of the system is shown. Images show cut view of species concentration every 60 s up to 300 s after the ejection process.

Strobilurins halt the production of ATP by blocking the electron transport at the level of the be,-complex, located within the mitochondrial Inner membrane, which separates the matrix from the intermembrane space (transmission electron microscope image). In a process, the so-called Q cycle, which was first proposed by the British biochemist Peter Dennis Mitchell (1920-1992), ubihydroquinone (also known as ubiquinol) is oxidized to ubiquinone, thereby transfering an electron to each, the Rieske iron-sulfur complex and the bi heme. While this cycle operates twice, four protons in total are pumped into the intermembrane space, and generate a proton gradient. 

Fig. 2. Image acquisition and processing steps to determine the transport of ts-045-G to the plasma membrane. HeLa cells were transfected with siRNAs on LabTek arrays as they are described in Chapter 1 of this issne. The ts-045-G transport assay was carried out as described in protocol 1.1 as described earlier in this chapter. Images were acquired sequentially using a lOX objective on a Scan R system using filters to detect specifically DAPI stained nuclei (A), Cy3 stained ts-045-G at the plasma membrane (B), and CFP-tagged ts-045-G (C). Images DT were generated as described in protocol 1.2. earlier in this chapter. R in (G) is the ratio of ts-045-G at the plasma membrane (measured in H) to ts-045-G expressed in cells (measured in I). Resnlts for siRNAs targeting the COPI component /3-COP, the COPII component Sec31p, and a p24 related membrane protein p26 are shown. The valnes are the average of two independent experiments (Bar = 50 /tm).

---