Anandamide inhibits oxidative phosphorylation in isolated liver mitochondria.

A study on the effect of anandamide (AEA) in energy coupling of rat liver mitochondria is presented. Micromolar concentrations of AEA, while almost ineffective on substrate supported oxygen consumption rate and on uncoupler stimulated respiration, strongly inhibited the respiratory state III. AEA did not change the rate and the extent of substrate generated membrane potential, but markedly delayed rebuilding by respiration of the potential collapsed by ADP addition. Overall, these data suggest that anandamide inhibits the oxidative phosphorylation process. Direct measurement of the F(o)F(1) ATP synthase activity showed that the oligomycin sensitive ATP synthesis was inhibited by AEA, (IC(50), 2.5 µM), while the ATP hydrolase activity was unaffected. Consistently, AEA did not change the membrane potential generated by ATP hydrolysis.

Lipidomic analysis of porcine olfactory epithelial membranes and cilia.

The use of the matrix 9-aminoacridine has been recently introduced in matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry analysis of both anionic and cationic phospholipids. In the present study, we take advantage of this technique to analyze the lipids of porcine olfactory mucosa and a membrane fraction enriched in cilia. Thin-layer chromatography (TLC) and (31)P-NMR analyses of the lipid extracts were also performed in parallel. MALDI-TOF-MS allowed the identification of lipid classes in the total lipid extract and individual lipids present in the main TLC bands. The comparison between the composition of the two lipid extracts showed that: (1) cardiolipin, present in small amount in the whole olfactory mucosa lipid extract, was absent in the extract of membranes enriched in olfactory cilia, (2) phosphatidylethanolamine species were less abundant in ciliary than in whole epithelial membranes, (3) sulfoglycosphingolipids were detected in the lipid extract of ciliary membranes, but not in that of epithelial membranes. Our results indicate that the lipid pattern of ciliary membranes is different from that of whole-tissue membranes and suggest that olfactory receptors require a specific lipid environment for their functioning.

The acylhalocapnines of halophilic bacteria: structural details of unusual sulfonate sphingoids.

Sulfonate sphingoids or sulfonolipids are bioactive unusual compounds found in members of the Bacteroidetes family. The present report describes the structures of sulfonolipids of halophilic bacteria, sharing structural similarity with compounds of fungal origin inhibiting the serine palmitoyl transferase and with capnines, known as antagonists of von Willebrandt factor. Two sulfonolipids (SL1 and SL2) were isolated from the lipid extract of the halophile Salisaeta longa and analyzed by ESI-MS/MS. SL1 and SL2 structures have in common the long chain aminosulfonate 2-carboxy-2-amino-3,4-hydroxy-17 methyloctadec-5-ene-1-sulfonic for which the common name of halocapnine is suggested. The hydroxyl group on carbon 3 of aminosulfonate moiety is acylated: iso C15 and iso hydroxy C15 chains are present in SL1 and SL2, respectively. The levels of the two different sulfonolipids in the bacterium were found to be modulated by the proportion of sodium and magnesium ions in the environment.

Characterization of polar membrane lipids of the extremely halophilic bacterium Salinibacter ruber and possible role of cardiolipin.

The lipid composition of the extremely halophilic bacterium Salinibacter ruber (Bacteroidetes) was investigated by thin layer chromatography, gas chromatography, high performance liquid chromatography and electrospray ionization-mass spectrometry. Polar lipids represent about 80% of the total lipid extract. The main polar lipids are a sulfonic acid analogue of ceramide (or capnine analogue), phosphatidylcholine, phosphatidylserine, dimethylphosphatidylethanolamine, phosphatidylglycerol, cardiolipin or bisphosphatidylglycerol, and a glycolipid. The major acyl chains in the phospholipids are C16:1 Delta9cis and C18:1 Delta11cis, while the sulfonolipid contains an amide-bound iso C15:0 fatty acid. On changing the salinity of the culture medium, no significant differences were found in the lipid profile or the unsaturation of the lipid fatty acyl chains. The structure of the cardiolipin, which represents 20% of polar lipids, has been elucidated by gas chromatography and electrospray ionization mass spectrometry analysis.