Fatty acid amides as modulators of phospholipase A2 activity

S46

Abstracts / Chemistry and Physics of Lipids 164S (2011) S45–S47

P 64 Anaerobiosis and cyanide increase cardiolipin membrane levels Simona Lobasso 1,∗ , Luigi Leonardo Palese 1 , Pietro Luca Martino 1 , Maristella Baronio 1 , Angela Corcelli 1,2 1

Department of Medical Biochemistry, Biology and Physics, University of Bari Aldo Moro, Bari, Italy 2 IPCF-CNR, Bari Unit, Bari, Italy

The importance of the content of anionic phospholipids (cardiolipin, CL and phosphatidylglycerol, PG) in the response of B. subtilis to different stress conditions, such as high salinity, anaerobic conditions, inhibition of respiratory chain and lack of nutrients, has been examined. Total lipids have been extracted from control and stressed BS168 cells and analysed by combining TLC and MALDITOF mass spectrometry. CL accumulates rapidly when the bacteria are: (1) incubated in high salt-containing medium, (2) resuspended in small volumes of isosmotic medium devoid of nutrients, (3) under reduced aeration, and (4) exposed to KCN. The increase of CL occurs at the expense of PG and is temperature-dependent. However it is not clear whether the CL enrichment is due to stimulation of the neosynthesis or reduction of lipid degradation. Comparative O2 consumption measurements of control and CLenriched bacterial cells indicate that CL accumulation is associated with resistance to KCN inhibition. It is suggested that high CL levels would buffer protons over the membrane surface, reducing the proton gradient dissipation, under conditions in which function of terminal oxidases is impaired. doi:10.1016/j.chemphyslip.2011.05.135 P 65 Direct MALDI-TOF/MS analyses of cardiolipin in intact membranes

Previously we have shown that is possible to directly analyze lipids from lyophilized archaeal membranes dry mixed with 9aminoacridine (Angelini et al., 2010). In the present study we have examined the possibility to detect cardiolipins directly in bacterial and eukaryotic membranes, avoiding the extraction/separation steps. MALDI-TOF/MS analyses of intact membranes isolated from various eukaryotic and microbial cells have been carried out by directly depositing isolated membranes over the target. After water evaporation a thin layer of saturated matrix solution (9aminoacridine in 2-propanol/acetonitrile 60/40, v/v) was spotted on dried membranes. Then the spectra are collected directly shooting this solid deposition with the laser of the instrument. Rat liver mitochondria, chromatophores isolated from Rhodobacter sphaeroides, membranes of bacteria (Bacillus subtilis) and archeons (Halobacterium salinarum, Halorubrum sp., Haloferax volcanii) have been analyzed. Results shown indicate that in all cases it is possible to detect cardiolipins of various structures and complexity, with a good signal-to-noise ratio and isotopic resolution. The novel approach here described allows the detection of CL even in small amount of biological samples and in a very short time. References Angelini, R., Babudri, F., Lobasso, S., Corcelli, A., 2010. MALDI-TOF/MS analysis of archaebacterial lipids in lyophilized membranes dry-mixed with 9-aminoacridine. J. Lipid Res. 51, 2818–2825. Chen, S., Tarsio, M., Kane, P.M., Greenberg, M., 2008. Cardiolipin mediates cross-talk between mitochondria and the vacuole. Mol. Biol. Cell 19, 5047–5058. Corcelli, A., 2009. The cardiolipin analogues of Archaea. Biochim. Biophys. Acta 1788, 2101–2106. Corcelli, A., Saponetti, M.S., Zaccagnino, P., Lopalco, P., Mastrodonato, M., Liquori, G.E., Lorusso, M., 2010. Mitochondria isolated in nearly isotonic KCl buffer: focus on cardiolipin and organelle morphology. Biochim. Biophys. Acta 1798, 681–687. Mannella, C.A., 2006. Structure and dynamics of the mitochondrial inner membrane cristae. Biochim. Biophys. Acta 1763, 542–548. Mileykovskaya, E., Zhang, M., Dowhan, W., 2004. Cardiolipin in energy transducing membranes. Biochemistry (Moscow) 70 (2), 154–158.

Roberto Angelini 1,∗ , Patrizia Lopalco 2 , Simona Lobasso 1 , Angela Corcelli 1,3

doi:10.1016/j.chemphyslip.2011.05.136

1

P 66

Department of Medical Biochemistry, Biology and Physics, University of Bari “Aldo Moro”, Bari, Italy 2 Institute for Microelectronics and Microsystems National Research Council (IMM-CNR), Lecce, Italy 3 Institute for Chemical-Physical Processes, National Research Council (IPCF-CNR), Bari, Italy Cardiolipin (CL) is a dimeric phospholipid present in mitochondria and bacterial membrane domains involved in bioenergetic functions, where it plays a key role in the functioning of many integral membrane enzymes involved in bioenergetic functions (Mileykovskaya et al., 2004). Moreover it can affect the inner membrane curvature (Corcelli et al., 2010) and fusion dynamics of mitochondria (Mannella, 2006), besides to be involved in important cellular functions apart from bioenergetics. A number of studies have shown a correlation between the cardiolipin levels and osmotic stability of mitochondria (Chen et al., 2008) as well as its role in the osmoregulation of microbial cells (Corcelli, 2009). Furthermore abnormal CL levels have been observed in some pathologies, such as the Barth syndrome and the Tangier disease. In these studies a correlation between CL levels and cells and/or organelles morphology has been suggested. Here we propose a new method to quickly gain information on CL content in biomembranes.

Fatty acid amides as modulators of phospholipase A2 activity Olga Sharko ∗ , Mikhail Kisel Institute of Bioorganic Chemistry, National Academy of Sciences of Belarus, Minsk, Belarus Fatty acid amides is a new class of biologically active compounds attracting increasing interest of many researchers due to their promising pharmaceutical effects. The present work concerns screening fatty acid amides as secretory phospholipase A2 modulators and estimating the impact of the fatty acid amide structure on the lipid–protein interaction. Our experiments revealed that main contribution to the enzyme modulation is provided by the length of acyl chain, its functionalization and degree of unsaturation. When the inhibition (activation) is exhibited by the amide with the certain acyl type, its magnitude depends on the amine group structure of the amide. doi:10.1016/j.chemphyslip.2011.05.137