Enhancer nonspecific form

Detection of a Specific and a Nonspecific Form of Enhancer Regulation... 

Enhancer substances stimulate the enhancer-sensitive neurons in the mesencephalon in a peculiar manner. Figure 3.11 shows the characteristics of the enhancer effect of (-)-BPAP added to isolated locus coerulei of rats. We see two bell-shaped concentration/effect curves. The one in the low nanomolar range, with a peak effect at 10 13 M concentration, clearly demonstrates the existence of a highly complex, specific form of enhancer regulation in noradrenergic neurons. The second, with a peak effect at 10-6 M concentration, shows the operation of a ten million times less sensitive, obviously nonspecific form of the enhancer regulation in these neurons (see Knoll et al. 2002b, for details). 

The second study of the enhancer effect on cultured telencephalic neurons was performed on cortical cells from 8-day-old chicken embryos (Lohman brown hybrid). This is the only study to date on nonmammalian brain cells. (-)-BPAP detected the operation of both the specific and nonspecific form of enhancer regulation in the cortical neurons of this avian species. The performance of the cortical neurons was enhanced in the low nanomolar concentration range of (-)-BPAP, with a peak effect at 10-14M concentration (Fig. 3.13). 

Among the derivative of HQ, 8-hydroxyquinoline-5-sulfonic acid (HQS) is attractive because of the enhanced water-solubility of the metal complexes it forms (Fig. 7.2). HQS is weakly fluorescent in solution. Investigating the effect of various metal ions and solution conditions on the fluorescence properties of HQS is the purpose of the experiment. By designing appropriate experiments, you can explore how HQS might be useful as either a specific or nonspecific fluorescent reagent. 

Lipids do not form an ideal fluid, but exist as a mixture of diverse species that show preferences in associating with each other as a result of head group attractions or repulsions, and packing effects in the hydrocarbon core. Small transient microdomains are formed by specific and nonspecific protein—protein, protein-lipid, and lipid-lipid interactions. A variety of techniques have shown that membrane proteins are surrounded by a dynamic boundary layer of lipids with an average composition distinct from the bulk phase. Membrane proteins, through their preferential association with specific lipids, can induce microdomains consisting of these boundary lipids and the lipids that interact preferentially with the boundary lipids. In turn, these microdomains enhance the formation of protein clusters. 

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