title: A rapid method for the extraction and analysis of carotenoids and other hydrophobic substances suitable for systems biology studies with photosynthetic bacteria.
abstract: A simple, rapid, and inexpensive extraction method for carotenoids and other non-polar compounds present in phototrophic bacteria has been developed. The method, which has been extensively tested on the phototrophic purple non-sulphur bacterium Rhodospirillum rubrum, is suitable for extracting large numbers of samples, which is common in systems biology studies, and yields material suitable for subsequent analysis using HPLC and mass spectroscopy. The procedure is particularly suitable for carotenoids and other terpenoids, including quinones, bacteriochlorophyll a and bacteriopheophytin a, and is also useful for the analysis of polar phospholipids. The extraction procedure requires only a single step extraction with a hexane/methanol/water mixture, followed by HPLC using a Spherisorb C18 column, with a mobile phase consisting of acetone-water and a non-linear gradient of 50%-100% acetone. The method was employed for examining the carotenoid composition observed during microaerophilic growth of R. rubrum strains, and was able to determine 18 carotenoids, 4 isoprenoid-quinones, bacteriochlorophyll a and bacteriopheophytin a as well as four different phosphatidylglycerol species of different acyl chain compositions. The analytical procedure was used to examine the dynamics of carotenoid biosynthesis in the major and minor pathways operating simultaneously in a carotenoid biosynthesis mutant of R. rubrum.
authors: Institute for System Dynamics, University of Stuttgart, Pfaffenwaldring 9, Stuttgart D-70569, Germany. judit.bona-lovasz@isys.uni-stuttgart.de.
authors: Judit
authors: J
authors: Bóna-Lovász
authors: Institute of Theoretical Chemistry, University of Stuttgart, Pfaffenwaldring 55, Stuttgart D-70569, Germany. bona@theochem.uni-stuttgart.de.
authors: Aron
authors: A
authors: Bóna
authors: Institute for System Dynamics, University of Stuttgart, Pfaffenwaldring 9, Stuttgart D-70569, Germany. michael.ederer@isys.uni-stuttgart.de.
authors: Michael
authors: M
authors: Ederer
authors: Institute for System Dynamics, University of Stuttgart, Pfaffenwaldring 9, Stuttgart D-70569, Germany. oliver.sawodny@isys.uni-stuttgart.de.
authors: Oliver
authors: O
authors: Sawodny
authors: Department of Bioenergetics, Institute of Biology, University of Stuttgart, Pfaffenwaldring 57, Stuttgart D-70569, Germany. robin.ghosh@bio.uni-stuttgart.de.
authors: Robin
authors: R
authors: Ghosh