Book of Abstracts: Albany 2003
June 17-21 2003
Lipids Participation in Cell Nucleus Signaling (Lipidomics) Analyzed by Biophysical Investigations, Liquid Chromatography and Biosensor Techniques
For a long time lipids have only been considered as the major structural elements of cell membranes or molecules which serve as efficient reserves for the storage of energy. In the last years, it has become clear that lipid classes active participate in cell function, such as phosphatidylcholine (PC), sphingolipids, and fatty acids (1, 2). Lipids represent the essential part of chromatin, while 100% of chromatin's cardiolipin and 60% of its cholesterol are DNA-bound (2, 3). This report describes the interaction of cholesterol in deciphering the mechanisms of underlying nuclear processes ? so called lipidomics.
Lipidomics investigations aim at understanding the functional implications of lipid diversity. First, lipids in different cell types or cellular organelles are analyzed by biochemical methods (1, 2). Second, analysis identifying interaction sequences and genes of specific lipids are performed by combinations of chromatography and spectroscopy methods (4). In the present study, the interaction of synthetic polynucleotide double strands with cholesterol was examined in diluted aqueous solutions by circular dichroism spectra, UV-absorption measurements, and biosensor investigations. All duplexes are influenced by cholesterol ligandation up to a ratio of 1 ligand per 2 base pairs, which could not be removed by ethanol dialysis procedure. All CD spectra of cholesterol- nucleic acid combinations remain the shape of the untreated nucleic acid.
Since techniques have evolved explosively in the fields of protein and nucleic acid research, the lipid function analysis requires development of innovative technology (5) that will be pointed out in the presentation. Since, cholesterol absorbs UV light only in the high-energy area at lambda <215 nm, it is difficult to analyze the complexes by HPLC techniques equipped only with optical sensors. We utilized a new biosensor technique (SENSOBI Ltd., Germany), based on conductivity measurements in aqueous and alcoholic solutions, which acts highly sensitive to small amount of organic molecules. The biosensor device was attached at the output of a common HPLC instrument, the chromatogram performed with first UV-detection at 210 nm and thereafter biosensor analysis. This paper describes our recent progress made through applications of liquid chromatography coupled with biosensor device to characterization of DNA adducts.
G. Bischoff *1
1Martin Luther University Halle-Wittenberg