Synthesis and Mesomorphic Properties of Liquid Crystals with 5-(4-Alkoxyphenylethynyl)tropolone.

New troponoid liquid crystals with 5-(4-alkoxyphenylethynyl)tropolone cores were synthesized. The 5-(4-alkoxyphenylethynyl)tropolones were obtained by the palladium-catalyzed cross-coupling of 5-iodotropolone with 4-alkoxyphenylacetylenes. The 2-alkoxy-5-(4-alkoxyphenylethynyl)tropones (1A) showed enantiotropic smectic phases, such as smectic A, C, and B.

Electrophysiological studies on the mechanism for enhanced intestinal transport of water-soluble compounds by antibiotic peptide bacitracin.

Bacitracin is an antibacterial cyclic dodecapeptide produced by Bacillus licheniformin. Besides antibacterial activity, it is reported to have a protease inhibitory activity and an absorption enhancing action. Here we determined the effects of bacitracin on transport of water-soluble dye fluoresceinisothiocyanate (FITC)-dextran across the rat intestinal mucosal membrane using an electrophysiological technique.

Enhancement of the small intestinal uptake of phenylalanylglycine via a H+/oligopeptide transport system by chemical modification with fatty acids.

The transport characteristics of chemically modified phenylalanylglycine (Phe-Gly) with butyric acid (C4-Phe-Gly) and caproic acid (C6-Phe-Gly) were examined using rabbit intestinal brush-border membrane vesicles (BBMVs). In the presence of an inwardly H+ gradient (pH 7.5 inside, pH 6.