Influence of immobilized biomolecules on magnetic bead plug formation and retention in capillary electrophoresis.

Significant changes in the formation and retention of magnetic bead plugs in a capillary during electrophoresis were studied, and it was demonstrated that these effects were due to the type of biological molecule immobilized on the surface of these beads. Three biological molecules, an antibody, an oligonucleotide, and alkaline phosphatase (AP), were attached to otherwise identical streptavidin-coated magnetic beads through biotin-avidin binding in order to isolate differences in bead immobilization in a magnetic field resulting from the type of biological molecule immobilized on the bead surface. AP was also attached to the magnetic beads using epoxy groups on the bead surfaces (instead of avidin-biotin binding) to study the impact of immobilization chemistry. The formation and retention of magnetic bead plugs were studied quantitatively using light scattering detection of magnetic particles eluting from the bead plugs and qualitatively using microscopy. Both the types of biomolecule immobilized on the magnetic bead surface and the chemistry used to link the biomolecule to the magnetic bead impacted the formation and retention of the bead plugs.

Constituents of cinnamon inhibit bacterial acetyl CoA carboxylase.

Cinnamon bark ( CINNAMOMUM ZEYLANICUM) is used extensively as an antimicrobial material and currently is being increasingly used in Europe by people with type II diabetes to control their glucose levels. In this paper we describe the action of cinnamon oil, its major component, TRANS-cinnamaldehyde, and an analogue, 4-hydroxy-3-methoxy- TRANS-cinnamaldehyde against bacterial acetyl-CoA carboxylase in an attempt to elucidate the mechanism of action of this well-known antimicrobial material. These natural products inhibited the carboxyltransferase component of ESCHERICHIA COLI acetyl-CoA carboxylase but had no effect on the activity of the biotin carboxylase component. The inhibition patterns indicated that these products bound to the biotin binding site of carboxyltransferase with TRANS-cinnamaldehyde having a K (i) value of 3.8 ± 0.6 mM. The inhibition of carboxyltransferase by 4-hydroxy-3-methoxy- TRANS-cinnamaldehyde was analyzed with a new assay for this enzyme based on capillary electrophoresis. These results explain, in part, the antibacterial activity of this well-known antimicrobial material.