MALDI-TOF/MS analysis of archaebacterial lipids in lyophilized membranes dry-mixed with 9-aminoacridine

Abstract

This article is available online at http://www.jlr.org erophospholipids, allowing a rapid, sensitive, and highly informative approach for the direct analysis of cell lipid extracts ( 2 ). Notably the use of the novel matrix 9-aminoacridine in MALDI-TOF/MS enables the fast and reliable detection of anionic phospholipids and also cardiolipin species ( 2 ).In our study we extended the use of 9-aminoacridine as a matrix for the MALDI-TOF/MS to glycerolipids and glycerophospholipids of extremely halophilic microorganisms belonging to the Archaea kingdom. The extremely halophilic archaeons are well adapted to life in NaClsaturated aquatic ecosystems, where they are exposed to extremely low water activity and desiccation stress.Glycerolipids and glycerophospholipids are defi ned as glycerol and glycerol-phosphate derivatives, respectively ( 3 ). Whereas in bacteria and eukaryotic cells, glycerolipids and glycerophospholipids are constituted by straight-chain fatty acids linked to glycerol by ester bonds, in the archaeal microorganisms, the hydrophobic chains are isopranoid chain alcohols linked to glycerol by ether bonds ( 4 ).The stereochemistry of archaebacterial membrane lipids is also different from that of other membrane lipids. In archaebacterial lipids, the glycerol group is alkylated at the sn -2 and sn -3 positions, at variance from bacterial and eukaryotic lipids, whose chains are linked at the sn -1 and sn -2 positions ( 4 ). The ether bond and the absence of unsaturations in the hydrophobic tail of the phospholipids (and other polar lipids present in archaeal membranes) Abstract A method of direct lipid analysis by MALDI mass spectrometry in intact membranes, without prior extraction/separation steps, is described. The purple membrane isolated from the extremely halophilic archaeon Halobacterium salinarum was selected as model membrane. Lyophilized purple membrane were grinded with 9-aminoacridine (9-AA) as dry matrix, and the powder mixture was crushed in a mechanical die press to form a thin pellet. Small pieces of the pellet were then attached to the MALDI target and directly analyzed. Recently, a matrix-assisted laser desorption/ionization time-of-fl ight mass spectrometry (MALDI-TOF/MS) approach, based on the use of 9-aminoacridine (9-AA) as matrix, has been developed for the rapid analysis of glyc- Ricerca (Fondi Ateneo), Ministero Italiano della Difesa (Contract No. 1999 and Regione Puglia (Grant code 15, Sens&MicroLab). This work was supported by Ministero Italiano dell'Università e della

Cardiolipin fingerprinting of leukocytes by MALDI-TOF/MS as a screening tool for Barth syndrome

“…It has been shown that this emerging analytical technique can be used to directly acquire lipid profi les of biological samples, thus skipping extraction and separation steps (30)(31)(32)(33). We successfully adopted this experimental approach to describe the lipid composition of bacterial and mitochondrial membranes ( 30,31,33 ) and to detect lipid markers in blood serum ( 32 ). Importantly, we found that the phosphatidylcholine-tolysophosphatidylcholine ratio could be easily determined by MALDI-TOF/MS analyses of native blood serum and followed as a clinical parameter in various diseases ( 32 ).…”

Methanothermobacter tenebrarum sp. nov., a hydrogenotrophic, thermophilic methanogen isolated from gas-associated formation water of a natural gas field

“…Lipid bands on the TLC plate were visualized using ninhydrin for amino lipids and either 30 % H 2 SO 4 or iodine vapour for all lipids. Some lipids visualized using iodine vapour were scraped and analysed by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS, AXIMA Resonance, Shimadzu) according to the procedure of Angelini et al (2010). Cells of M. thermautotrophicus DSM 1053 T at the late exponential phase were also examined as a reference.…”

The Light‐Activated Proton Pump Bop I of The Archaeon Haloquadratum walsbyi

“…In addition, while two cardiolipin analogs are present in the lipid pattern of standard PM (34,47), no cardiolipins have been found in claret membranes. While both cardiolipin analogs were found to be enriched in bacteriorhodopsin chromatographic bands of H. salinarum (34), only small amounts of BPG were detected among residual phospholipids associated with solubilized Bop I of Haloquadratum .…”