Phospholipid Composition of Gluconobacter cerinus

Phospholipids of Gluconobacter cerinus were investigated. The cells of this bacterium were found to have cardiolipin, phosphatidylglycerol, phosphatidylethanolamine and phosphatidylcholine together with three ornithine-containing lipids. Phosphatidylcholine was the most abundant of these phospholipids, and calculated at 31.0% of total phospholipids in the cells at the late logarithmic phase. The fatty acid of this lipid was composed of palmitate, stearate and vaccenate, and there were no remarkable differences in quality among fatty acids of these four phospholipids. The phosphatidylcholine was also found in other acetic acid bacteria.     

Phospholipid Composition of Desulfovibrio Species

The phospholipids of Desulfovibrio desulfuricans, Norway strain, D. vulgaris, and D. gigas were examined in relationship to their qualitative and quantitative composition. D. desulfuricans and D. vulgaris exhibited an essentially identical phospholipid composition consisting of phosphatidylethanolamine, phosphatidylglycerol, cardiolipin, and lysophosphatidylserine. Phosphatidylserine (10.9%) was present in D. desulfuricans but was not detected in D. vulgaris. D. gigas was found to contain only two phospholipids, phosphatidylethanolamine (30%) and phosphatidylglycerol (70%). An ornithine-containing lipid was detected in D. gigas which was not present in the other two Desulfovibrio species.     

Phospholipid Composition of Bacillus subtilis

Bacillus subtilis contained at least five phospholipids, four of which have been isolated and identified as a polyglycerol phospholipid, probably cardiolipin, phosphatidylglycerol, phosphatidylethanolamine, and lysylphosphatidylglycerol. Further purification of the latter phosphoglyceride was obtained by high-voltage electrophoresis, and it was shown that this treatment removed amino acid-containing, nonlipidic material from the phosphoglyceride. This associated material, which is not covalently linked to the lipid, gave rise to minor amounts of a number of amino acids, other than lysine, in acid hydrolysates of the lysylphosphatidylglycerol. The phospholipid composition of B. subtilis appeared to depend on the growth conditions. Addition of glucose to the medium lowered the pH during growth; this was accompanied by an increase in the amount of lysylphosphatidylglycerol and a decrease in the phosphatidylglycerol content, when compared with growth at neutral pH. The amount of the other phospholipids and the total amount of phospholipid remained constant under the different conditions. The shape and the osmotic susceptibility of the protoplasts of this organism appeared to depend on the growth conditions. Cells harvested from a neutral growth medium gave spherical protoplasts which lysed rapidly, whereas cells grown in an acidic medium maintained their rod-shaped form to a great extent after the cell wall had been removed, even after being suspended in a hypotonic medium. The latter observation suggests the presence of a more rigid membranous structure in cells which have been exposed to a low environmental pH during growth.     

Phospholipid Composition and Metabolism of Micrococcus denitrificans

The phospholipid composition of Micrococcus denitrificans was unusual in that phosphatidyl choline (PC) was a major phospholipid (30.9%). Other phospholipids were phosphatidyl glycerol (PG, 52.4%), phosphatidyl ethanolamine (PE, 5.8%), an unknown phospholipid (5.3%), cardiolipin (CL, 3.2%), phosphatidyl dimethylethanolamine (PDME, 0.9%), phosphatidyl monomethylethanolamine (PMME, 0.6%), phosphatidyl serine (PS, 0.5%), and phosphatidic acid (0.4%). Kinetics of ³²P incorporation suggested that PC was formed by the successive methylations of PE. Pulse-chase experiments with pulses of ³²P or acetate-1-¹⁴C to exponentially growing cells showed loss of isotopes from PMME, PDME, PS, and CL with biphasic kinetics suggesting the same type of multiple pools of these lipids as proposed in other bacteria. The major phospholipids, PC, PG, and PE, were metabolically stable under these conditions. The fatty acids isolated from the complex lipids were also unusual in being a simple mixture of seven fatty acids with oleic acid representing 86% of the total. Few free fatty acids and no non-extractable fatty acids associated with the cell wall or membrane were found.     

Heterogeneity of Phospholipid Composition in the Bacterial Membrane

Heterogeneity in the distribution or binding of the membrane phospholipids was demonstrated in the membrane fragments released from Haemophilus parainfluenzae by treatment with ethylenediaminetetraacetic acid (EDTA)-tris(hydroxymethyl)-aminomethane (Tris). The membrane fragments released early in the EDTA-Tris treatment contained two- to fivefold higher proportions of cardiolipin and phosphatidylglycerol and less phosphatidylethanolamine as well as phospholipids with threefold lower specific activity of the phospholipid phosphate after a short pulse of (32)P than were found in the residue. Heterogeneity was best demonstrated with shorter EDTA-Tris treatments and shorter periods of growth with (32)P. EDTA-Tris treatment appeared to progressively strip phospholipids from the cells that were synthesized at progressively later times.     

Effect of Modification of Membrane Phospholipid Composition on Phospholipid Methylation in Aggregating Cell Culture

The effect of the presence of nitrogenous bases in the growth medium of fetal rat brain aggregating cell cultures was investigated. The presence of either N-methylethanolamine (MME) or N,N-dimethylethanolamine (DME) in the growth medium resulted in significant increase of the corresponding phospholipid, phosphatidyl-N-monomethylethanolamine (PMME) or phosphatidyl-N,N-dimethylethanolamine (PDME). They represented 28% and 32% of the total phospholipids, respectively. The presence of the new phospholipids was accompanied by a significant decrease of phosphatidylethanolamine (PE) and phosphatidylcholine (PC). Cells grown in the presence of ethanolamine or choline had only barely detectable amounts of PMME and PDME. Intact cells previously grown with the bases were incubated with [methyl-3H]methionine. Incubation of cells previously grown in presence of the bases MME and DME resulted in a marked increase of radioactivity in the corresponding phospholipids possessing one additional methyl group, PDME and PC respectively. The incorporation of S-adenosyl[methyl-3H]methionine (AdoMet) was examined in cell homogenates incubated in presence or absence of either PMME or PDME acceptors. The addition of these exogenous phospholipids caused a three-or fourfold stimulation of radioactivity incorporated into the total phospholipids of cells grown in the absence of nitrogen bases. The cells grown in presence of either MME or DME in the culture medium did not show an increased incorporation of methyl groups from AdoMet into the total phospholipids after addition of exogenous acceptors. This work suggests that MME and DME incorporated into the corresponding phospholipids function as effective substrates for phospholipid-N-methylation.     

Phospholipid Composition of Venezuelan Equine Encephalitis Virus

Phospholipid analyses of Venezuelan equine encephalitis virus showed that virus propagated in L-cell monolayers had a higher sphingomyelin content and a lower phosphatidylcholine content than virus grown in chick fibroblast monolayers. Virus of L-cell origin also was found to possess greater thermal stability than virus derived from the chick fibroblast cell.     

The Effects of N-Terminal Fragments of Immunophilin on Phospholipid Composition of Rat Brain and Human Erythrocyte Membranes

Rat brain slices and human erythrocyte membranes have been incubated in the presence of water-soluble synthetic peptide fragments corresponding to residues 1–9 and 1–15 of the N-terminus of immunophilin and the effects on the phospholipid composition examined. During a 2 h incubation in the presence of 1 nM, 0.1 M, and 10 M concentrations of the peptides there were observed significant and dose-dependent decreases in the amounts of phosphatidylcholine and phosphatidylethanolamine, as well as increases in the amounts of phosphatidylserine and, to a less extent, phosphatidylinositol, cardiolipin and lysophosphatidylcholine. The overall decrease in the neutral phospholipids of rat brain, and no changes in human erythrocyte membranes with the simultaneous increase in the acidic phospholipids, both in brain and erythrocyte membranes, tended to counteract any changes in the phospholipid composition of the material studied. The results are discussed in terms of the possible effects of immunophilin on modulating phospholipid turnover in brain cell erythrocyte membranes.     

Cell Envelope Phospholipid Composition of Burkholderia multivorans

Burkholderia multivorans causes opportunistic pulmonary infections in cystic fibrosis and immunocompromised patients. The purpose of the present study was to determine the nature of the phospholipids and their fatty acid constituents comprising the cell envelope membranes of strains isolated from three disparate sources. A conventional method for obtaining the readily extractable lipids fraction from bacteria was employed to obtain membrane lipids for thin-layer chromatographic and gas chromatography-mass spectrophotometric analyses. Major fatty acid components of the B. multivorans readily extractable lipid fractions included C_16:0 (palmitic acid), C_16:1 (palmitoleic acid), and C_18:1 (oleic acid), while C_14:0 (myristic acid), ΔC_17:0 (methylene hexadecanoic acid), C_18:0 (stearic acid), and ΔC_19:0 (methylene octadecanoic acid) were present in lesser amounts. Fatty acid composition differed quantitatively among strains with regard to C_16:0, C_16:1, ΔC_17:0, C_18:1, and ΔC_19:0 with the unsaturated:saturated fatty acid ratios being significantly less in a cystic fibrosis type strain than either environmental or chronic granulomatous disease strains. Phospholipids identified in all B. multivorans strains included lyso-phosphatidylethanolamine, phosphatidylglycerol, phosphatidylethanolamine, and diphosphatidylglycerol in similar ratios. These data support the conclusion that the cell envelope phospholipid profiles of disparate B. multivorans strains are similar, while their respective fatty acyl substituent profiles differ quantitatively under identical cultivation conditions.     

Effect of Membrane Phospholipid Composition and Charge of the Signal Peptide of Escherichia coli Alkaline Phosphatase on Efficiency of Its Secretion

The secretion of the Escherichia coli alkaline phosphatase with a different charge of signal peptide due to replacement of positively charged Lys(–20) has been studied depending on the phospholipid composition of the membranes and the activity of the translocational ATPase—protein SecA. Changing the signal peptide charge, along with a change in phospholipid composition, has been shown to reduce the efficiency of secretion. In the absence of phosphatidylethanolamine the membrane contains anionic phospholipids only, and the dependence of secretion on the signal peptide charge decreases. The dependence of secretion on membrane phospholipid composition and the signal peptide charge is also determined by the activity of SecA protein. If SecA is inactivated by sodium azide, then the dependence of secretion on anionic phospholipids increases; on the contrary, higher content of anionic phospholipids (in the absence of phosphatidylethanolamine) decreases the dependence of secretion on the SecA activity. The results suggest a direct interaction of positively charged signal peptide with negatively charged membrane phospholipids under initiation of secretion and also interdependent contribution of the signal peptide charge, anionic phospholipids, and translocational ATPase to secretion.     

Erythrocyte Phospholipid and Polyunsaturated Fatty Acid Composition in Diabetic Retinopathy

Background

Long chain polyunsaturated fatty acids (LCPUFAs) including docosahexaenoic acid and arachidonic acid are suspected to play a key role in the pathogenesis of diabetes. LCPUFAs are known to be preferentially concentrated in specific phospholipids termed as plasmalogens. This study was aimed to highlight potential changes in the metabolism of phospholipids, and particularly plasmalogens, and LCPUFAs at various stages of diabetic retinopathy in humans.

Methodology and Principal Findings

We performed lipidomic analyses on red blood cell membranes from controls and mainly type 2 diabetes mellitus patients with or without retinopathy. The fatty acid composition of erythrocytes was determined by gas chromatography and the phospholipid structure was determined by liquid chromatography equipped with an electrospray ionisation source and coupled with a tandem mass spectrometer (LC-ESI-MS/MS). A significant decrease in levels of docosahexaenoic acid and arachidonic acid in erythrocytes of diabetic patients with or without retinopathy was observed. The origin of this decrease was a loss of phosphatidyl-ethanolamine phospholipids esterified with these LCPUFAs. In diabetic patients without retinopathy, this change was balanced by an increase in the levels of several phosphatidyl-choline species. No influence of diabetes nor of diabetic retinopathy was observed on the concentrations of plasmalogen-type phospholipids.

Conclusions and Significance

Diabetes and diabetic retinopathy were associated with a reduction of erythrocyte LCPUFAs in phosphatidyl-ethanolamines. The increase of the amounts of phosphatidyl-choline species in erythrocytes of diabetic patients without diabetic retinopathy might be a compensatory mechanism for the loss of LC-PUFA-rich phosphatidyl-ethanolamines.     

The Concentration of Vanadium in Pathologically Altered Human Kidneys

This study evaluated serum and hair mineral and trace element levels as well as levels of other nutritional factors affecting growth and appetite in young children with non-organic failure to thrive (NOFTT) based on the presence or types of feeding difficulty (FD). Between August 2012 and July 2015, 136 children less than 6 years of age with NOFTT were included. FD was diagnosed based on Wolfson criteria and divided into subtypes according to Chatoor’s classification. Clinical data were reviewed, and serum and hair mineral levels were measured. Of all assessed serum and hair minerals, only hair sulfur contents differed significantly between subjects with and without infantile anorexia (39,392 ± 2211 vs. 40,332 ± 2551 μg/g, P = 0.034). There were no differences in serum and hair mineral levels between children with and without sensory food aversion. Hair copper contents were significantly lower in children with FD of reciprocity (12.3 ± 6.0 vs. 22.4 ± 25.1 μg/g, P = 0.049). While hair zinc contents were also lower, the difference was not statistically significant (49.2 ± 26.8 vs. 70.6 ± 41.0 μg/g, P = 0.055). Only hair manganese contents were significantly lower in children with posttraumatic FD (0.12 ± 0.04 vs. 0.26 ± 0.73 μg/g, P = 0.037). In conclusion, there were no differences in most serum and hair mineral levels in children with NOFTT, except for relatively lower hair levels of sulfur, copper and possibly zinc, and manganese in infantile anorexia, reciprocity, and posttraumatic types of FD, respectively.     

Comparison of the Phospholipid Composition of Bifidobacterium and Lactobacillus Strains

Phospholipid composition of 10 Bifidobacterium strains of human intestinal origin and of 9 Lactobacillus strains was determined by quantitative two-dimensional thin-layer chromatography. Phospholipids of three Bifidobacterium strains from honey bees and of two strains from bovine rumen liquor were qualitatively investigated. Diphosphatidylglycerol and phosphatidylglycerol were present in strains of both genera. All Bifidobacterium strains contained as specific phospholipids a new polyglycerolphospholipid, compound 15, and its lyso derivatives, earlier detected in B. bifidum var. pennsylvanicus. Also, lyso compounds of diphosphatidylglycerol and alanyl phosphatidylglycerol were only present in this genus in variable amounts. Lysyl phosphatidylglycerol was the only ninhydrin-positive phospholipid in seven Lactobacillus strains. In L. delbrückii and L. helveticus it was absent and partially replaced by an unidentified ninhydrin-negative phospholipid. The differences in phospholipid composition between bifidobacteria and lactobacilli may be another argument to differentiate these two genera.     

Developmentally Regulated Changes in Phospholipid Composition in Murine Molar Tooth

In order to explore the possibility that phospholipids are differently expressed during the cascade of events leading to tooth formation, we decided to carry out simultaneous biochemical, histological and electron histochemical studies. High performance thin-layer chromatography and gas–liquid chromatography were used to compare the composition of embryonic mouse first molar tooth germs at day 18 of gestation (E18) and at birth (D1), erupting teeth at day 7 (D7) and erupted molars at day 21 (D21). For the latter, non-demineralized and EDTA-demineralized lipid extracts were analysed separately. Moreover, an ultrahistochemical study was carried out using the iodoplatinate reaction which retains and visualizes phospholipids. Developmentally regulated changes occurred and were closely correlated with an increase in cell membrane phospholipids. Gradual accumulation of phospholipids was identified in the extracellular matrix, at an early stage of tooth germ development within the basement membrane and later, as predentine/dentine and enamel components participating in mineralization processes. Matrix vesicles transiently present in dentine were partly responsible for the lipids that were detected. A first group of phospholipids including phosphatidylcholine as the major membrane-associated phospholipid and phosphatidylinositol as the intracellular second messenger increased by a factor of 2.3 between E18 and D21. This increase is probably associated with cell lengthening and was relatively modest compared with the higher increase detected for a second group of phospholipids, namely phosphatidylethanolamine (×4.8), phosphatidylserine (×5.9) and sphingomyelin (×5.4). This second group of extracellular matrix-associated phospholipids constituted 68% of the demineralized lipid extract and, therefore, contributes to the mineralization of dental tissues.     

Phospholipid and Ganglioside Composition in Rat Brain After Chronic Intake of Ethanol

Abstract: A total of 18 60-day-old male Wistar rats were divided into three groups of six animals each. One group was fed a basal diet containing high levels of protein, fat, carbohydrate, vitamins, and minerals and separately a solution of 25% sucrose-32% ethyl alcohol (wt/vol). A second group was offered water as the only drinking fluid and a similar solid diet, except that carbohydrate replaced ethanol isocalorically. A third group was maintained on the basal diet ad libitum . All groups of animals were killed in a sober state after 6 months of chronic ethanol treatment and lipid analyses were performed on brain homog-enates. Chronic treatment of the animals with ethanol produces statistically significant modification of the phospholipid and ganglioside patterns in rat brain. A statistically significant decrease of the total phospholipid content and of some of the investigated fractions, i.e., phos-phatidylcholine and phosphatidylserine, as well as an increase of phosphatidylinositol were observed. Chronic alcohol consumption was associated with a statistically significant increase in the total amount of ganglioside in rat brain. An increase in most of the investigated ganglioside fractions was indicated but the difference was statistically significant only for trisialoganglioside GT_1b. The amount of disialoganglioside GD_1a in these brains was decreased after chronic intake of ethanol.     

Extractable Lipids of Gram-Negative Marine Bacteria: Phospholipid Composition

Phospholipid compositions of 20 strains of marine and estuarine bacteria were determined. Results showed that phospholipids of marine bacteria differed very little from those of nonmarine organisms with phosphatidylethanolamine, phosphatidylglycerol, and diphosphatidylglycerol being the predominant phospholipids in all strains examined. Lyso-phosphatidylethanolamine occurred in significant quantities among a number of the marine bacteria, and two of the isolates contained significant quantities of poly-beta-hydroxybutyrate. Effects of age and growth temperature on the phospholipid composition were also investigated. It is suggested that phylogenetic relationships among bacteria may be correlated with phospholipid composition.     

Phospholipid Composition in Spinal Cord Regions after Ischemia/Reperfusion

Ischemia-reperfusion induced changes in concentration of phosphatidylcholine (PC), phosphatidylethanolamine (PE), phosphatidylserine (PS), phosphatidylinositol (PI) and sphingomyelin (SM) in the gray matter taken in toto, white matter, dorsal horns, intermediate zone and ventral horns of the rabbit's spinal cord were studied and compared with neurohistopathological changes. With the exception of PI concentration in the dorsal horns, ischemia of 25 min caused significant degradation of all phospholipids. While short-lasting recirculation (1 h) did not returned the levels of phospholipids to control values, postischemic recirculation for 3 h sharply increased the resynthesis of all phospholipids, but only the concentration of PE, PS, and PI in the dorsal horns and PC in the intermediate zone significantly improved and returned close to control values. Corresponding neurohistopathological changes resulting after the same reperfusion periods are given.