ABSTRACT
Sulfur amino acids, such as taurine, hypotaurine, and thiotaurine, were found in high quantities in tissues of marine symbiotic organisms (e.g., bivalves, tubeworms) living close to hydrothermal vent sites. Therefore, they are assumed to play a key role in the S-oxidizing base metabolism or sulfide detoxification. We propose here a specific, rapid, and original analytical procedure for the direct determination of sulfur amino acids at the level of a few parts per billion in biological samples, avoiding the classical low specific post-column ortho-phthaldialdehyde derivatization step required by non-ultraviolet-absorbing molecules. Indeed, by coupling liquid chromatography on a porous graphitic stationary phase under isocratic conditions (10 mM ammonium acetate buffer adjusted to pH 9.3) to tandem mass spectrometry (ionization process by pneumatically assisted electrospray in negative ion mode), it is possible to perform specific quantification of these metabolites in less than 10 min directly in biological matrices without any derivatization step or other tedious sample treatments. Thus, taurine, hypotaurine, and thiotaurine have been identified and assayed in several deep sea organisms, showing that the developed method is well suited for this kind of application.
Subject(s)
Chromatography, Liquid/methods , Invertebrates/chemistry , Mass Spectrometry/methods , Taurine/analogs & derivatives , Taurine/analysis , Animals , Invertebrates/physiology , Marine Biology , Oceans and Seas , Sensitivity and Specificity , SymbiosisABSTRACT
Free amino acids were analyzed in tissues of symbiotic bivalves from hydrothermal vent sites at Galapagos rift, and cold-seeps in Japan trench and Barbados subduction area. Diaminopimelic acid (a fragment of the bacterial cell wall mureid complex) is, in some cases, one of the most abundant compounds. It's presence in the tissues of the bivalves is related to exchanges between host and symbionts. Diaminopimelate concentration differences among species may correspond to both taxonomic bacterial differences and different carbon translocation processes from bacteria to host. Variation among individuals may correspond to fluctuation of micro-environmental conditions.
