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At least 19 recordsLinked to original sources
PubMed1975

Electron spin resonance studies on the lipid-protein interaction between cardiolipin and anti-cardiolipin antibodies.

Electron spin resonance measurements were performed in order to investigate the influence of anti-cardiolipin antibodies on cardiolipin-containing liposomes. The physical state of the lipid structures and the alterations caused by the interaction with specific antibody were determined by measuring the freedom of motion of spin-labeled stearic acid derivatives incorporated into the lipid structures. The interaction of the cardiolipin-containing liposomes with the anti-cardiolipin antibodies reduced the mobility of the spin-labeled stearic acid probe I (12, 3), whose nitroxide group is assumed to be located near the polar region of the lipid bilayer. The restricted mobility, which qualitatively resembles the interaction of cardiolipin liposomes with calcium ions, is probably the result of a tighter packing of the polar groups in their crystalline array. The binding sites of the cardiolipin structures for anti-cardiolipin antibodies and Ca2 ions seem to be identical. As indicated by the spin-labeled stearic acid probe I (1, 14), the apolar region of the lipid bilayer is not affected by the interaction of the cardiolipin-containing liposomes with the anti-cardiolipin antibodies.

Antigen-Antibody Reactions↗
PubMed1979

Reaction between peroxidized phospholipid and protein: II. Molecular weight and phosphorus content of albumin after reaction with peroxidized cardiolipin.

Peroxidized cardiolipin (diphosphatidylglycerol) reacts covalently with albumin. Incubation of albumin with increasing amounts of peroxidized cardiolipin produces a gradual increase in molecular size. Incubation with a small amount of peroxidized cardiolipin (molar ratio of cardiolipin/albumin 21) produces a mixture of complexes that differs considerably with respect to the number of cardiolipin molecules bound per molecule of albumin. With larger amounts of peroxidized cardiolipin (molar ratios of cardiolipin/albumin 54 and 114), the complexes formed seem to be of a more uniform type since the numbers of cardiolipin molecules bound per molecule of albumin are similar. No polymerization occurs for reactions in which up to at least 15 moles of cardiolipin have become bound per mole of albumin, and 20--25 moles may be found with only very little polymerization. Only when the ratio of peroxidized cardiolipin to albumin was increased to a high value of 314 did polymerization occur. The present findings show that extensive covalent binding of peroxidized cardiolipin to albumin can occur without intermolecular crosslinking of the protein.

Albumins↗
PubMed1979

Phase transition characteristics of diphosphatidyl-glycerol (cardiolipin) and stereoisomeric phosphatidyldiacylglycerol bilayers. Mono- and divalent metal ion effects.

Synthesis and phase transition chaaracteristics of aqueous dispersions of the homologous (12 : 0, 14 : 0, 16 : 0) diphosphatidylglycerols (cardiolipins) and phosphatidyldiacylglycerols are reported. Electron microscopy of the negatively stained aqueous dispersions reveals a characteristic lamellar structure suggesting that these phospholipid molecules are organized as bilayers in the aqueous dispersions. The phase transition temperature (Tm) and the enthalpy of transition (delta H) increase monotonically with chain length in the cardiolipin and phosphatidyldiacylglycerol series; Tm for phosphatidyldiacylglycerol is higher than that for cardiolipin of the same chain-length. The transition temperatures for the enantiomeric sn-3,3- and sn-1,1-phosphatidyldiacylglycerol and for the diastereomeric, meso-sn-1,3-phosphatidyldiacylglycerol are approximately the same. The molar enthalpy for the transition of cardiolipin-NH+4 bilayers is approximately twice the value for the phosphatidylcholines of the same chain length, i.e., the molar enthalpy per acyl chain is approximately the same in the two systems. The transition temperatures for metal ion salts of C16-cardiolipin exhibit a biphasic dependence upon the unhydrated ionic radii, i.e., the highest Tm is observed for Ca2+-cardiolipin and decreases for the salts of ions with smaller and larger ionic radii than that of Ca2+. The lowest Tm is observed for Rb+-cardiolipin. Monovalent metal salts of cardiolipin exhibit two phase transitions. This effect may result from different conformational packing of the four acyl chains due to differences in metal-phosphate binding.

Cardiolipins↗
PubMed1979

Involvement of calcium ions in the properties of cardiolipin-associated erythrocyte acetylcholinesterase.

Lipoprotein forms of acetylcholinesterase from bovine erythrocytes gave non-linear Arrhenius plots with a break at 20 degrees C and contained cardiolipin. The break in the Arrhenius plot was abolished by incubation of the enzyme in high salt (I = 1.8), but only in Ca2+ -chelating conditions. At I = 1.8 neither NaCl alone, CaCl2 nor sodium phosphate at acidic pH abolished the break. However, at this ionic strength either NaCl in 2 mM sodium phosphate (pH 7.4) or sodium phosphate, pH 8, or 1.0 M Na2CO3/NaHCO3 (pH 8.5--10, were able to remove the break. The Arrhenius plot break was regenerated by the addition of Ca2+ to the high salt-treated enzyme with mild homogenization, but could not be regenerated in the presence of EDTA unless CaCl2 was added in excess of the EDTA. Conditions which abolished the break enabled endogenous cardiolipin to be removed from the enzyme by chloroform/methanol extraction Cardiolipin from acetylcholinesterase incubated in high salt in Ca2+ -chelating conditions was not accessible to digestion by phospholipase A2, and was not separated from the enzyme by flotation in a sucrose density gradient or by Sephadex G-200 chromatography. Thus both Ca2+ and cardiolipin appear to be inaccessible, possibly by being tightly associated in the hydrophobic core of the enzyme by ionic and hydrophobic forces. Ca2+ may modulate the temperature dependence of acetylcholinesterase activity through a functionally linked ionic interaction with the enzyme-cardiolipin complex.

Acetylcholinesterase↗
PubMed1979

Labelling of cardiolipin in vitro.

A method for labelling the polar head groups of cardiolipin is described. Labelling was carried out on sonicated cardiolipin/water suspensions. The free hydroxyl group of cardiolipin was oxidised with an excess of p-(diazonium) benzenesulfonic acid (DABS) and then reduced with NaB3H4. Isopropanol was oxidised in the presence of DABS to test the reactivity of the diazonium salts, and the reaction product was analysed by means of gas-chromatography. Labelled cardiolipin, identified by thin-layer chromatography (TLC), was chromatographically pure and identical to untreated cardiolipin. The hydrolysis of cardiolipin confirmed that the labelling was at the level of polar head groups.

Cardiolipins↗
PubMed1978

Cardiolipin: a stereospecifically spin-labeled analogue and its specific enzymic hydrolysis.

The spin-labeled cardiolipin 1-(3-sn-phosphatidyl)-3-[1-acyl-2-(16-doxylstearoyl)glycero(3)phosphol]-sn-glycerol has been prepared. The stereoselective synthesis makes use of the monolysocardiolipin 1-(3-sn-phosphatidyl)-3-[1-acyl-2-lyso-sn-glycero(3)phospho]-sn-glycerol, available from the stereospecific hydrolysis of cardiolipin by phospholipase A2 (phosphatide 2-acylhydrolase, EC 3.1.1.4) of Trimeresurus flavoviridis. The results of treatment of the spin-labeled cardiolipin with the cardiolipin-specific phospholipase D (phosphatidylcholine phosphatidohydrolase, EC 3.1.4.4) (Hemophilus parainfluenzae) of known specificity and with phospholipase C (phosphatidylcholine cholinephosphohydrolase, EC 3.1.4.3) of Bacillus cereus are consistent with the assigned structure. The spin-labeled cardiolipin is further characterized and the unique features of this diastereomer are discussed in the context of the unusual stereochemistry of the natural phospholipid.

Cardiolipins↗
PubMed1975

Adaptive changes in cardiolipin content of Staphylococcus aureus grown in different salt concentrations.

Adaptive changes in cardiolipin content were examined in Staphylococcus aureus 209P using the 32P pulse-labelling method. Cardiolipin synthesis showed increased adaptation when cells grown in normal medium were transferred into high NaCl containing medium. When S. aureus cultured in 10% NaCl medium was transferred back to normal medium, cardiolipin concentration decreased to the normal level within 3 hours. The catabolic rate of cardiolipin in the cells was much slower in the 5% NaCl medium than in normal medium. The cardiolipin synthetase activity was examined by isolated membrane fraction from S. aureus grown both in normal and 10% NaCl medium. The activity was higher by two-fold in membrane fractions from cells cultured in 10% NaCl-containing medium than in membranes from cells cultured in normal medium.

Adaptation, Biological↗
PubMed1977

Further studies on the cardiolipin phosphodiesterase of Escherichia coli.

The cardiolipin phosphodiesterase of Escherichia coli was further characterized. This enzyme has a pH optimum of 7.0 and is Mg2+ dependent. Mn2+ and Co2+ could replace Mg2+ but other divalent cations were inhibitory or without effect. The enzyme is not periplasmic and does not appear to be associated with membrane fractions prepared by different methods. It is recovered as a soluble protein in the cytosol fraction but could not be readily purified because of its instability. With cell-free systems, a requirement for ATP or ADP could be shown under certain defined conditions. Other nucleotides were less effective or ineffective in stimulating the phosphodiesterase. The cells displayed the highest activity during the middle to late exponential stage but no marked requirement for ATP was apparent when the phosphodiesterase was obtained from such freshly grown cells. If, however, cells were starved for several hours in saline medium, the cardiolipin phosphodiesterase level fell and a requirement for added ATP could be shown. The cardiolipin phosphodiesterase is an enzyme distinct from cardiolipin synthase. The assay conditions are quite different from each of these enzymes as are their subcellular distributions.

Adenosine Diphosphate↗
PubMed2026

Remodeling of host lipid metabolism by Wolbachia strain wAlbB is associated with lipid accumulation and cardiolipin dysregulation in the Aedes aegypti fat body.

BACKGROUND: The intracellular symbiont Wolbachia, particularly the wAlbB strain, is a promising biocontrol agent against mosquito-borne diseases. Although Wolbachia infection is known to perturb host metabolism, the underlying mechanisms, especially those related to lipid metabolism, remain poorly understood. METHODS: We performed an integrated multi-level analysis of the Aedes aegypti fat body in uninfected and wAlbB-infected mosquitoes, combining histology, biochemistry, untargeted liquid chromatography-mass spectrometry (LC-MS) lipidomics, Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways enrichment analysis, reverse transcription quantitative PCR of key metabolic genes, and quantification of acetyl-coenzyme A (acetyl-CoA) and reduced nicotinamide adenine dinucleotide (NADH) levels. RESULTS: wAlbB infection increased fat body wet weight and thickness, accompanied by accumulation of triglyceride and of lipid droplets. Lipidomic analysis further revealed extensive lipidome remodeling, with elevated free fatty acid, diglyceride, and triglyceride, but broad depletion of glycerophospholipids, particularly cardiolipin. These changes were supported by transcriptional alterations: upregulation of fatty acid synthase 1 and glycerol-3-phosphate acyltransferase 1, and downregulation of adipose triglyceride lipase and carnitine palmitoyltransferase 1. Cardiolipin depletion correlated with downregulation of genes involved in its synthesis and remodeling, including phosphatidylglycerophosphate synthase and calcium-independent phospholipase A2γ. These lipid changes were also associated with accumulation of acetyl-CoA and NADH. CONCLUSIONS: Our findings suggest that wAlbB infection is associated with extensive lipid metabolic remodeling in the Aedes aegypti fat body, characterized by accumulation of neutral lipids and cardiolipin depletion, accompanied by transcriptional remodeling of key metabolic enzymes. This study establishes the fat body as a primary tissue-level hub for Wolbachia-associated lipid remodeling and provides a foundational framework for future mechanistic investigations into host-symbiont metabolic interactions.

Animals↗
PubMed1977

Cardiolipin synthesis during the cell cycle of the yeast Saccharomyces cervisiae.

Cardiolipin synthesis was studied during the aerobic synchronous growth of aerobically grown yeast Saccharomyces cerevisiae. The time course of the synthesis was stepwise and the rise in cardiolipin level in cells coincided in time with the increase in cytochrome oxidase activity. This finding supports the notion of discontinuous completion of the inner mitochondrial membrane and hints at a close relation between cardiolipin and cytochrome oxidase activity.

Aerobiosis↗
PubMed1979

Cardiolipin accumulation in the inner and outer membranes of Escherichia coli mutants defective in phosphatidylserine synthetase.

Mutants of Escherichia coli defective in phosphatidylserine synthetase (pss) make less phosphatidylethanolamine than normal cells, and they are temperature sensitive for growth. We have isolated a new mutant, designated RA2021, which is better than previously available strains in that the residual phosphatidylethanolamine level approaches 25% after 4 h at 42 degrees C. The total amount of phospholipid normalized to the density of the culture is about the same in RA2021 (pss-21) as in the isogenic wild-type RA2000 (pss(+)). Consequently, there is a net accumulation of polyglycerophosphatides in the mutant, particularly of cardiolipin. The addition of 10 to 20 mM MgCl(2) to a culture of RA2021 prolongs growth under nonpermissive conditions and prevents loss of cell viability, but it does not eliminate the temperature-sensitive phenotype. Divalent cations, like Mg(2+), do not correct the phospholipid composition of the mutant, but may act indirectly by balancing the negative charges of phosphatidylglycerol and cardiolipin. To determine the effects of the pss mutation on membrane composition, we have examined the subcellular distribution of the polyglycerophosphatides that accumulate in these strains. All of the excess anionic lipids of RA2021 are associated with the envelope fraction and are distributed equally between the inner and outer membranes. The protein compositions of the isolated membranes do not differ significantly in the mutant and wild type. The fatty acid composition of RA2021 is almost the same as wild type at 30 degrees C, but there is more palmitic and cyclopropane fatty acid at 42 degrees C. These results demonstrate that the modification of the polar lipid composition observed in pss mutants affects both membranes and that cardiolipin, which is not ordinarily present in large quantities, can accumulate in the outer membrane when it is overproduced by the cell. The altered polar headgroup composition of the outer membrane in pss mutants may account, in part, for their hypersensitivity to the aminoglycoside antibiotics.

CDPdiacylglycerol-Serine O-Phosphatidyltransferase↗
PubMed1976

[Biosynthesis of cardiolipin in the rat hepatoma 27 and Jensen sarcoma].

The localization of cardiolipin biosynthesis in rat hepatoma 27 and Jensen sarcoma cells was investigated. In both tumors cardiolipin was found to be synthesized only in the mitochondria as is the case in normal rat liver. It is concluded that the occurrence of cardiolipin in the microsomes of the tumor cells may be connected with a transmembrane exchange of phospholipids in vivo.

Animals↗
PubMed1978

Function of phospholipids in Escherichia coli. Characterization of a mutant deficient in cardiolipin synthesis.

Screening of a collection of temperature-sensitive mutants of Escherichia coli for defects in phospholipid metabolism led to the isolation of a mutant deficient in cardiolipin synthesis. The defective gene, named cls, is closely linked to the trp marker and maps at about Minute 27 on the E. coli chromosome. After transfer of cls to a defined genetic background by transduction, the mutant has the following properties as compared to an isogenic wild type. Exponentially growing cells show a reduction in cardiolipin content by a factor of at least 15 (less than 0.2 mol % of the total phospholipids). A crude membrane fraction derived from the mutant is unable to synthesize cardiolipin from phosphatidylglycerol in vitro. The mutant has no distinctive phenotype regarding its growth properties, membrane-associated respiratory functions, or the ability to insert bacteriophage M13 coat protein into the cell envelope. The cls mutation confers a 5-times reduction in the turnover of the phosphate moiety of phosphatidylglycerol.

Cardiolipins↗
PubMed1978

Polymorphic phase behaviour of cardiolipin as detected by 31P NMR and freeze-fracture techniques. Effects of calcium, dibucaine and chlorpromazine.

1. The influence of Ca2+ on the polymorphic phase behaviour of cardiolipin has been investigated employing 31P NMR and freeze-fracture techniques. The close correlation between the results obtained here and previous X-ray studies (Rand, R.P. and Sengupta, S. (1972) Biochim. Biophys. Acta 255, 484--492) confirms 31P NMR as a useful analytical procedure for investigating the polymorphic phase behaviour of hydrated phospholipids. 2. Ca2+ induces formation of the hexagonal (H11) phase via an intermediary phase which is observed at Ca2+/cardiolipin ratios of less than 1 (mol/mol). This intermediary appears to consist of "inverted' structure which lies adjacent to regions of bilayer structure. 3. The local anaesthetics dibucaine and chlorpromazine produce similar phase changes for cardiolipin as does Ca2+. It is suggested that the anaesthetics interact with the membrane in their charged form and induce their effects by charge neutralization.

Calcium↗
PubMed1979

Phase changes of cardiolipin vesicles mediated by divalent cations.

Small unilamellar vesicles were prepared from cardiolipin and produced the hexagonal II phase when dialyzed against CaCl2 or MgCl2. Upon removal of the cation by dialysis against EDTA large unilamellar vesicles were formed. The events of the transition from the lamellar to hexagonal phase and back to the lamellar phase are described.

Calcium↗
PubMed1977

Immune lysis of spin label loaded liposomes incorporating cardiolipin; a new sensitive method for detecting anticardiolipin antibodies in syphilis serology.

Liposomes prepared from a mixture of the pure lipids cholesterol, lecithin and cardiolipin (molar ratio 50/45/5), are able to bind antibodies directed against Treponema pallidum. When the liposomes are loaded with the water soluble spin label tempocholine chloride, the release of spin label from the liposomes can be monitored directly by observing changes in the paramagnetic resonance (ESR) spectrum from the spin label. The method offers a convenient technique for monitoring the complement-mediated lysis of liposomes, and may be applied in the serological diagnosis of syphilis, and a method for quantitative measurement of complement.

Animals↗
PubMed1976

Action of polymyxin B on bacterial membranes: phosphatidylglycerol- and cardiolipin-induced susceptibility to polymyxin B in Acholeplasma laidlawii B.

To identify the polymyxin receptor molecules in the membranes of living microorganisms, fusion of intact Acholeplasma laidlawii B with lipid vesicles was investigated according to the procedure of Grant and McConnell (1973). The naturally polymyxin-resistant A. laidlawii B was treated with phospholipid vesicles prepared from purified phospholipids of the polymyxin-susceptible Salmonella typhimurium G30. A. laidlawii B absorbed between 15 and 45% of its own lipid content of the added tritium-labeled phospholipids without loss of viability. Association with the acidic components phosphatidylglycerol and cardiolipin produced a 10- to 30-fold increase in polymyxin susceptibility, which was not obtained with egg-phosphatidylcholine and mixed phosphatidylcholine-phosphatidylethanolamine vesicles. The polymyxin-sensitized cells bound 12 times more radioactive antibiotic than resistant cells. The phosphatidylglycerol-induced susceptibility was abolished by serum fraction V (Cohn) proteins.

Acholeplasma laidlawii↗