Lipid composition of the electron transport membrane of Haemophilus parainfluenzae

The principal lipids associated with the electron transport membrane of Haemophilus parainfluenzae are phosphatidylethanolamine (78%), phosphatidylmonomethylethanolamine (0.4%), phosphatidylglycerol (18%), phosphatidylcholine (0.4%), phosphatidylserine (0.4%), phosphatidic acid (0.2%), and cardiolipin (3.0%). Phospholipids account for 98.4% of the extractible fatty acids. There are no glycolipids, plasmalogens, alkyl ethers, or lipo amino acid esters in the membrane lipids. Glycerol phosphate esters derived from the phospholipids by mild alkaline methanolysis were identified by their staining reactions, mobility on paper and ion-exchange column chromatography, and by the molar glycerol to phosphate ratios. Eleven diacyl phospholipids can be separated by two-dimensional thin-layer chromatography. Each lipid served as a substrate for phospholipase D, and had a fatty acid to phosphate ratio of 2:1. Each separated diacyl phospholipid was deacylated and the glycerol phosphate ester was identified by paper chromatography in four solvent systems. Of the 11 separated phospholipids, 3 were phosphatidylethanolamines, 2 were phosphatidylserines, and 2 were phosphatidylglycerols. Phosphatidylcholine, cardiolipin, and phosphatidic acid were found at a single location. Phosphatidylmonomethylethanolamine was found with the major phosphatidylethanolamine. Three distinct classes of phospholipids are separable according to their relative fatty acid compositions. (i) The trace lipids consist of two phosphatidylethanolamines, two phosphatidylserines, phosphatidylcholine, phosphatidic acid, and a phosphatidylglycerol. Each lipid represents less than 0.3% of the total lipid phosphate. These lipids are characterized by high proportions of the short (C(10) to C(14)) and long (C(19) to C(22)) fatty acids with practically no palmitoleic acid. (ii) The major phospholipids (93% of the lipid phosphate) are phosphatidylethanolamine, phosphatidylmonomethylethanolamine, and phosphatidylglycerol. These lipids contain a low proportion of the short (C(19)) fatty acids. Palmitic and palmitoleic acids represent over 80% of the total fatty acids. (iii) The fatty acid composition of the cardiolipin is intermediate between the other two classes. Both palmitoleic and the longer fatty acids represent a significant proportion of the total fatty acid.     

Lipid composition of Mycoplasma neurolyticum

The total lipid content of Mycoplasma neurolyticum comprises about 14% of the dry weight of the organisms and is about equally distributed between the phospholipid and the neutral-glycolipid fractions. The neutral lipids were identified as triglycerides, diglycerides, and cholesterol. The glycolipid fraction contained 1-O-beta-glucopyranosyl-d-2,3-diglyceride and 1-[O-beta-d-glycopyranosyl-(1-->6)-O-beta-d-glucopyranosyl]-d-2,3-diglyceride. The latter lipid is structurally identical to the diglucosyl diglyceride which occurs in Staphylococcus aureus. The phospholipids of the organism consist of a fully acylated glycerophosphoryl-glycerophosphoryl glycerol, phosphatidic acid, diphosphatidyl glycerol, phosphatidyl glycerol, and amino acyl esters of phosphatidyl glycerol. Phosphatidic acid and phosphatidyl glycerol account for greater than 90% of the phospholipids of organisms in the exponential phase of growth. The predominant fatty acids found in all of the acyl lipids were palmitic, stearic, and oleic acids.     

Lipid composition of the fishes Heterotis niloticus,Brycenus nurse,Gnathonemus cyprinoides and Sarotherodon galilaeus from a small lake in Nigeria

Lipid composition of Heterotis niloticus, Brycenus nurse, Gnathonemus cyprinoides and Sarotherodon galilaeus, which vary in scale thickness, were studied. Heterotis niloticus (very thick scales) had the lowest lipid content (13%), while G. cyprinoids (light scales) had the highest lipid content (26%). The common neutral lipids were cholesterol, free fatty acids and cholesterol esters, while diphosphatidyl glycerol, phosphatidyl glycerol and phosphatidyl ethanolamine were the most predominant phospholipids.     

Lipids of Bacteroides melaninogenicus

The lipids of Bacteroides melaninogenicus were readily extractable with chloroform-methanol. Three per cent of the fatty acids were not extractable. The neutral lipids contained 4% of the extractable fatty acids, the stench characteristic of these organisms, and 0.5 mumole of vitamin K(2) isoprenologues K(2)-35, K(2)-40, and K(2)-45 per g (dry weight). This is one-fifth to one-tenth of the vitamin K(2) level found in other bacteria. Ninety-six per cent of the extractable fatty acids were associated with the phospholipids (60 mumoles of lipid phosphate/g, dry weight), which consisted of the diacyl lipids phosphatidic acid, phosphatidyl serine, and phosphatidyl ethanolamine (with phosphatidyl glycerol and cardiolipin in one strain). The unusual phosphosphingolipids ceramide phosphorylethanolamine, ceramide phosphorylglycerol, and ceramide phosphorylglycerol phosphate accounted for 50 to 70% of the lipid phosphate. In protoheme-requiring strains, the protoheme concentration in the growth medium regulated the growth rate and the amount of enzymatically reducible cytochrome c. There were no gross changes in the lipid composition in cells containing different levels of enzymatically reducible cytochrome c.     

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.     

Evidence for a Composite State of an F′his,gnd Element and a Cryptic Plasmid in a Derivative of Salmonella typhimurium LT2

The zoospores of Blastocladiella emersonii, when derived from cultures grown on solid media, contain about 11% total lipid. This lipid was separated chromatographically on silicic acid into neutral lipid (46.6%), glycolipid (15.8%), and phospholipid (37.6%). Each class was fractionated further on columns of silicic acid, Florisil, or diethylaminoethyl-cellulose, and monitored by thin-layer chromatography. Triglycerides were the major neutral lipids, mono- and diglycosyldiglycerides were the major glycolipids, and phosphatidylcholine and phosphatidylethanolamine were the major phospholipids. Other neutral lipids and phospholipids detected were: hydrocarbons, free fatty acids, free sterols, sterol esters, diglycerides, monoglycerides, lysophosphatidylcholine, lysophosphatidylethanolamine, phosphatidic acid, phosphatidylserine, and phosphatidylinositol. Palmitic, palmitoleic, stearic, oleic, gamma-linolenic, and arachidonic acids were the most frequently occurring fatty acids. When B. emersonii was grown in (14)C-labeled liquid media, lipid again accounted for 11% of both mature plants and zoospores released from them. The composition of the lipid extracted from such plants and spores was also the same; however, it differed markedly from that of the lipid in spores harvested from solid media, consisting of 28.3% neutral lipid, 12.0% glycolipid, and 59.7% phospholipid. The major lipids were again triglycerides for neutral lipids, mono- and diglycosyldiglycerides for glycolipids, and phosphatidyl choline and phosphatidylethanolamine for phospholipids.     

Lipids of a T Strain of Mycoplasma

Cholesterol, free fatty acids, and phosphatidic acid are the predominant lipids of a T strain of Mycoplasma. The remaining neutral lipids are composed of cholesteryl esters, triglycerides, and diglycerides. Three glucose-containing glycolipids are present in trace amounts. In addition to phosphatidic acid, the phospholipids are comprised of phosphatidyl glycerol, diphosphatidyl glycerol, and phosphatidyl ethanolamine. Another polar lipid was found to be ninhydrin-positive and phosphate-free. It appears to be a diamino hydroxy compound containing adjacent fatty acid ester and N-acyl groups.     

Fatty Acid Composition of the Complex Lipids of Staphylococcus aureus During the Formation of the Membrane-bound Electron Transport System

In Staphylococcus aureus, 64 fatty acids could be separated by gas-liquid chromatography. The fatty acids consisted of normal, iso, and anteiso saturated fatty acids of from 10 to 21 carbon atoms. Of the total fatty acids, 2 to 4% were normal, iso, and anteiso monoenoic fatty acids. Positional isomers of the normal monoenoic fatty acids could be detected. The fatty acids could be extracted, leaving 1 to 2% of the total fatty acids in the residue. The proportions of the fatty acids in the residue and the total lipids differed significantly. The lipid extract contained less than 0.12% free fatty acid. Between 5 and 10% of the lipid fatty acids were associated with neutral lipids. The majority of the fatty acids were associated with the complex lipids: mono- and diglucosyl diglyceride, phosphatidyl glycerol, lysyl phosphatidyl glycerol, and cardiolipin. The proportions of the fatty acids changed markedly between bacteria grown anaerobically (no membrane-bound electron transport system) and those grown aerobically (containing a functional electron transport system). In each of the complex lipids, the proportions of the fatty acids, as well as the magnitude and direction of change in the molar quantity of the fatty acids per bacterium, changed dramatically between these growth conditions. Since the glucosyl diglycerides and phospholipids were formed from the same pool of diglyceride intermediates, the marked differences in fatty acids indicate that acyl transferase activities must be an important part of complex lipid metabolism in S. aureus.     

Phospholipid metabolism during bacterial growth

Haemophilus parainfluenzae incorporates glycerol and phosphate into the membrane phospholipids without lag during logarithmic growth. In phosphatidyl glycerol (PG), the phosphate and unacylated glycerol moieties turn over and incorporate radioactivity much more rapidly than does the diacylated glycerol. At least half the radioactivity is lost from the phosphate and unacylated glycerol in about 1 doubling. The total fatty acids turn over slightly faster than the diacyl glycerol. In phosphatidyl ethanolamine (PE), which is the major lipid of the bacterium, ethanolamine and phosphate turn over and incorporate radioactivity at least half as fast as the phosphate in PG. The glycerol of PE did not turn over in 4 bacterial doublings. In phosphatidic acid the glycerol turns over at one-third the rate of phosphate turnover. By means of a modified method for the quantitative recovery of 1,3-glycerol diphosphate from cardiolipin, the phosphates and middle glycerol of cardiolipin were shown to turn over more rapidly than the acylated glycerols during bacterial growth. There is no randomization of the radioactivity in the 1- and 3-positions of the glycerol in the course of 1 doubling. The fatty acids of PG turn over faster than those in PE. In both lipids the 2-fatty acids turn over much faster than the 1-fatty acids. At both positions the individual fatty acids have their own rates of turnover. The distribution of fatty acids between the 1- and 2-positions is the same as in other organisms, with more monoenoic and long-chain fatty acids at the 2-position. The different rates of turnover and incorporation of radioactivity into different parts of the lipids suggest that exchange reactions may be important to phospholipid metabolism.     

Drug-induced foam cell reactions in rats, II. Chemical analysis of lipids stored in lungs and foam cells after treatment with chlorphentermine, 5-[p-(fluoren-9-ylidenemethyl)phenyl]-2-piperidineethanol (RMI 10.393) and 1-chloramitriptyline.

Lipidosis and foam cell reaction was induced in rat lungs by repeated administration of chlorphentermine, RMI 10.393 (=5-[p-(fluoren-9-ylidenemethyl)phenyl]-2-piperidineethanol), and 1-chloramitriptyline. Foam cell and lung lipids were extracted and separated in classes by thin-layer chromatography. Phospholipids were determined by phosphorus analysis, while neutral lipids were measured densitometrically. In lungs of drug-treated rats lecithin, phosphatidyl glycerol, phosphatidic acid, phosphatidyl inositol and free fatty acids accumulated in varying amounts. All other lipids were present in normal or reduced concentrations. Foam cells of chlorphentermine- and RMI 10.393-treated rats contained mainly phospholipids, i.e. lecithin and only small amounts of neutral lipids, i.e. cholesterol. Foam cells induced by 1-chloramitriptyline contained besides phospholipids also large amounts of neutral lipids, i.e. cholesterol, free fatty acids and cholesterol esters. This study and recent reports of others show that certain drugs produce a generalized metabolic disturbance characterized by accumulation of various lipids in several tissues. The distribution patterns of lipids induced by various drugs may differ considerably. This indicates that several biochemical mechanisms may be involved in the pathogenesis of drug-induced lipidosis.     

Die Lipide von Endomycopsis vernalis bei verschiedener Stickstoff-Ernährung

1. Endomycopsis vernalis was cultivated on media with different N supply: series A 1%, series B 0,125% asparagine. Sonified cells were extracted and yielded 14.3% (A) and 65.3 (B) total lipids/non lipid dry matter respectively.
2. Neutral and complex lipids were separated by rubber membrane dialysis. There is no difference in the percentage of complex lipids of both series. The increase of lipids in cells grown on low N level is due to a higher content of neutral lipids.
3. Components of the neutral lipids, analysed by DC, were diglycerides, triglycerides, free and esterified ergosterol. Their percentage is influenced by the nutritional conditions. There is a significant increase of triglycerides and of sterol esters in the high lipid cells of series B.
4. Methyl esters of component fatty acids of glycerides and sterol esters were analyzed by GLC. Saturated acids C₁₄, C₁₅, C₁₆, C₁₇, C₁₈, monoenic acids C₁₆ and C₁₈, linoleic and linolenic acids were found to be present. Major acids were in all cases 18:1 (17–57%), 18:2 (18–50%) and 16:0 (10–18%). Linolenic acid is higher in di-and triglycerides of low lipid cells of series A than in high lipid cells of series B. Both qualitative and quantitative differences of fatty acids were found in sterol esters of series A and B respectively.
5. The major components of complex lipids, identified by DC and isolated by CC, in both series, were phosphatidyl choline (A:36.5, B:41.0%) and phosphatidyl ethanolamine (A:24.9, B:20.5%) in addition to small amounts of lysophosphatidyl choline, lysophosphatidyl ethanolamine, phosphatidyl serine, monophosphoinositide, diphosphatidyl glycerol and, possibly cerebroside like substances.
6. Methyl esters of the fatty acids of phosphatidyl choline and ethanolamine from both series were determined by GLC. In all samples 16:0, 18:0, 18:1, 18:2 and 18:3 acids were present besides of traces of 16:1 and 17:0. In contrast to neutral lipids the major acid of phospholipids is linoleic (53–58%), followed by oleic (8–24%) and linolenic acid (1–18%). The percentages of palmitic (4–8%) and stearic acids (tr.-1%) are small. Low lipid cells of series A differ from high lipid cells of series B by an increase of linolenic, and a decrease of linoleic acids, both in phosphatidyl choline and phosphatidyl ethanolamine.

     

CHANGES IN CEREBRAL CORTICAL LIPIDS IN COBALT-INDUCED EPILEPSY

Abstract– In control rats and in rats rendered epileptic by insertion of cobalt slivers into the cerebral cortex, total free fatty acids, free cholesterol, esterified cholesterol, triglycerides and phospholipids were measured in normal and lesion areas of cerebral cortex. The cortical lipid profile of the adult rat resembled that of the whole brain of very young rats rather than that of adult whole brain, with the principal differences from whole adult brain being lower total lipid content, increased proportions of phosphatidyl choline in the phospholipid fraction, and higher levels of cholesterol esters. Cobalt-induced epilepsy was associated with significant changes in cerebral cortical lipids in the area of the lesion and in the non-necrotic tissue adjacent to the lesion. The total lipid in the area of the lesion decreased sharply as a result of reductions in free cholesterol and total phospholipids. The levels of cholesterol esters and triglycerides increased in the area of the lesion, and cholesterol esters were also increased in the adjacent tissue. In addition there were decreases in the proportion of phosphatidyl ethanolamine in the phospholipids from the lesion site and adjacent tissue and decreases in the proportions of oleic, arachidonic and nervonic acids (unsaturated acids), and an increase in the proportions of lignoceric acid in the phospholipids. In the site of the lesion only, we observed a decrease in phospholipid palmitic acid and an appreciable increase in the proportions of an unidentified long-chained fatty acid.     

Separation of neutral lipids and free fatty acids by high-performance liquid chromatography using low wavelength ultraviolet detection

Normal phase, isocratic high-performance liquid chromatography methods are described for the separation of neutral lipid and fatty acid classes using low wavelength detection. Prior to high-performance liquid chromatography, methods were developed and are described for the separation of phospholipids from neutral lipids and fatty acids using small (600 mg) silica Sep-PaksTM. Recoveries of cholesteryl esters, triglycerides, fatty acids, and phospholipids from the silica columns were greater than 95%. Two mobile phases are described for lipid class separation by high-performance liquid chromatography. The first mobile phase, hexane-2-propanol-acetic acid 100:0.5:01, resulted in incomplete separation of cholesteryl ester and triglyceride but excellent separations of fatty acids and cholesterol. The second mobile phase, hexane-n-butyl chloride-acetonitrile-acetic acid 90:10:1.5:0.01, resulted in complete separation of the four lipid classes. This mobile phase also separated individual triglycerides and fatty acids based on the number of double bonds. Recoveries of radiolabeled lipids for the four lipid classes from high-performance liquid chromatography was greater than 95% with both mobile phases.     

Characterization of gastric mucosal membranes: lipid composition of purified gastric microsomes from pig, rabbit, and frog

The lipid compositions of the gradient-purified gastric microsomal membranes from the fundic mucosa of pig, rabbit, and frog were determined. The total lipid content varied widely. Compared to the rabbit (21.6 ± 0.6 mg/100 mg protein), the pig had about twice as much and the frog about three times as much lipid. The levels of cholesterol were higher in both mammalian species (about 32% of the lipid) compared to frog (23%). Phospholipids accounted for about 45, 54, and 52% of the total microsomal lipids from pig, rabbit, and frog and the molar ratios of cholesterol to phospholipid in the three species were 1.95, 1.6, and 1.17, respectively. Phosphatidyl choline and phosphatidyl ethanolamine together constituted about 75% of the total phospholipids in pig and frog and 93% in rabbit gastric microsomes. Sphingomyelin comprised 19.3, 3.2, and 1.5% in pig, rabbit, and frog, respectively. Phosphatidyl inositol constituted 5, 2.7, and 23.6% in pig, rabbit, and frog, respectively. The ratios of phosphatidyl ethanolamine to phosphatidyl choline were 1.17, 1.1, and 0.85 in pig, rabbit, and frog, respectively. The saturated fatty acids 16:0 and 18:0 and the unsaturated fatty acid 18:1 and 18:2 were the predominant fatty acids in all phospholipids. The ratios of saturated to unsaturated fatty acids were between 0.8 and 0.9 in phosphatidyl choline and 0.27 and 0.5 in phosphatidyl ethanolamine from all three species. The contributions by saturated fatty acids were much more in phosphatidyl inositol and sphingomyelin than in phosphatidyl choline and phosphatidyl ethanolamine from all species. Position 1 of phosphatidyl choline had 63% saturated and 37% unsaturated fatty acids; while the reverse was true for position 2. Phosphatidyl ethanolamine, however, had 85% saturated fatty acids in position 1 compared to only 25% in position 2. Arachidonic acid (20:4) was present in significant amounts in all species located exclusively at position 2 of both phosphatidyl choline and phosphatidyl ethanolamine.     

Modification of the fatty acid composition of individual phospholipids and neutral lipids after infection of the simian erythrocyte by Plasmodium knowlesi

Using capillary gas-liquid chromatography, we have analyzed the alteration in the total fatty acid, phospholipid and neutral lipid compositions of the monkey erythrocyte, after infection by the malarial parasite Plasmodium knowlesi. Data based on fatty acid quantitation show that the phospholipid composition is altered, with particularly large increases in phosphatidylcholine (PC) and phosphatidylethanolamine (PE), the most abundant phospholipids in normal and P. knowlesi-schizont-infected cells. Unesterified fatty acids were found to be less abundant in infected cells. The total fatty acid content of the cell is increased 6-fold during infection, and total fatty acid composition is also changed: the infected cells are richer in palmitate (+23%), oleate (+29%) and linoleate (+89%), but contained less stearate (-27%) and arachidonate (-40%). The determination of the fatty acid composition of individual phospholipids, neutral lipids and unesterified fatty acids showed that choline-containing phospholipids (PC and sphingomyelin) were not as altered in their fatty acid pattern as anionic phospholipids (PE, phosphatidylserine (PS) and phosphatidylinositol (PI) and lysophosphatidylcholine (lysoPC). Specific alterations in the fatty acid compositions of individual phospholipids were detected, whereas the rise in linoleic acid was the only change during infection that was recovered in each phospholipid (except PC), neutral lipid and unesterified fatty acids. The fatty acid composition of the neutral lipids and unesterified fatty acids was particularly modified: the only rise in arachidonic acid level was observed in these lipid classes after infection. The total plasmalogen level of the erythrocyte is decreased in infected cells (-60%), but their level is increased in PI.     

The Polyunsaturated Fatty Acids of Marine and Freshwater Cryptomonads1

SYNOPSIS Fatty acids were examined of photosynthetic and non-photosynthetic marine and freshwater cryptomonads cultured as photoauxotrophs, photoheterotrophs and heterotrophs at various incubation temperatures and constant light intensity. Photo-synthetic marine and freshwater forms contained octadecatrienoic, octadecatetraenoic, eicosapentaenoic and docosahexaenoic (all-cis, ω3 acids) as the major polyunsaturates, and a freshwater heterotroph contained mostly the octadecatrienoic acid. The polar lipids of a marine, photosynthetic form, Cryptomonas sp., included the usual thylakoid membrane lipids of the chloroplasts of eukaryotic, photosynthetic cells: galactosyl diglycerides, phosphatidyl glycerol and a sulfolipid. Also present were 2 choline-containing phospholipids: phosphatidyl choline and an unknown. Ninhydrin-positive and inositol-containing lipids were not detected. Octadecatetraenoic acid comprised 75% of the total fatty acids of the monogalactosyl diglyceride fraction. The phosphatidyl glycerol was acylated mostly by ω13 trans-hexadecaenoic acid and the eicosapentaenoic acid. Evolutionary relationships of cryptomonads as mirrored in lipid composition are discussed.     

Identification of lipids associated with the ability of tumor cells to resist humoral immune attack.

Certain metabolic inhibitors or chemotherapeutic agents that increase the susceptibility of line-1 or line-10 guinea pig hepatoma cells to humoral immune attack were studied for their effects on the ability of the cells to synthesize lipids. A direct correlation was found between the drug-induced increase in sensitivity to antibody-C mediated killing and the inhibition of the ability of the cells to incorporate acetate, glycerol, and fatty acids into complex cellular lipids. Drug-treated cells recultured in drug-free medium regained their resistance to antibody-C mediated killing; these cells recovered their ability for complex lipid synthesis at this time. Thin layer chromatography of CHCl3:CH3OH lipid extracts from these cells indicated that the drug-induced increase in susceptibility to humoral immune attack correlated with the inhibition of acetate, glycerol, and fatty acid incorporation into cardiolipin and triglyceride in line-10 cells and the inhibition of incorporation of these compounds into cardiolipin alone in line-1 cells. No direct correlation was found between the sensitivity of the cells to humoral immune attack and the ability of the cells to incorporate precursors of lipid synthesis into other lipid moieties (sphyngomyelin, phosphatidyl serine, phosphatidyl choline, phosphatidyl glycerol, or cholesterol esters). The synthesis of cardiolipin and triglycerides, therefore, appears to be associated with the mechanism whereby these tumor cells resist antibody-C mediated killing.     

Lipid Composition of Bacillus cereus During Growth and Sporulation

The lipid composition of Bacillus cereus during growth and sporulation was examined. The total lipid extract accounted for 2 to 3% of the dry weight of the cells and consisted of neutral lipids (30 to 40%) and phospholipids (60 to 70%). Phospholipids were separated by thin-layer chromatography into eight components; phosphatidyl ethanolamine, phosphatidyl glycerol, and diphosphatidyl glycerol were the major phospholipids and accounted for over 90% of the total. Also identified was a diglycosyl diglyceride and an alanine ester of phosphatidyl glycerol. Diphosphatidyl glycerol was more difficult to extract than the other components in vegetative and stationary-phase cells, but became increasingly easy to extract during spore maturation, and during sporulation cellular levels increased. Phosphatidyl glycerol had a high turnover rate; it accounted for about 70% of the phospholipid synthesis throughout sporulation but only represented between 30 and 40% of the total phospholipid at any time. Phosphatidyl ethanolamine, on the other hand, accounted for about 20% of the synthesis but was the major phospholipid (50 to 60% of the total).     

Phospholipids from Bacillus stearothermophilus

The lipids of Bacillus stearothermophilus strain 2184 were extracted with chloroform-methanol and separated into neutral lipid and three phospholipid fractions by chromatography on silicic acid columns. The phospholipids were identified by specific staining reactions on silicic acid-impregnated paper, by chromatography of alkaline and acid hydrolysis products, and by determination of acyl ester:glycerol:nitrogen:phosphorus molar ratios. The total extractable lipid was 8% of the dry weight of whole cells and consisted of 30 to 40% neutral lipid and 60 to 70% phospholipid. The phospholipid consisted of diphosphatidyl glycerol (23 to 42%), phosphatidyl glycerol (22 to 39%), and phosphatidyl ethanolamine (21 to 32%). The concentrations of diphosphatidyl glycerol and phosphatidyl glycerol were lower in 2-hr cells than in 4- and 8-hr cells. Whole cells were fractionated by sonic treatment and differential centrifugation. The total lipid content, expressed in per cent of dry weight of each fraction was: whole protoplasts, 10%; membrane fraction, 18%; 30,000 x g particulate fraction, 22%; and 105,000 x g particulate fraction, 26%. The relative phospholipid concentrations in each fraction were about the same. As had been previously reported, none of the phospholipid was stable to alkaline hydrolysis.     

Changes in Glycolipid and Phospholipid Compositions in Cotyledons of Germinating Soybeans

This investigation was conducted to observe changes in the compositions of fatty acids, glycolipids (GL) and phospholipids (PL) in cotyledons of soybean seeds which were germinated either in the dark or the light at 28°C for 8 days. The patterns of changes in lipid composition depended on the germinating conditions tested. In general, non-polar lipids were metabolized at a faster rate than polar lipids. Changes in lipid contents in cotyledons were also observed more clearly with the polar lipids than with the non-polar ones, especially in the light-grown seedlings. The major component of lipid, GL in chloroplasts, appeared rapidly at an earlier stage in the cotyledons of light-grown seedlings. During germination of soybean seeds, acyl sterylglucoside in cotyledons decreased rapidly, but monogalactosyl diglyceride and digalactosyl diglyceride (DGD) increased in the light-grown seedlings, whereas sterylglucoside and DGD increased in the dark-grown seedlings.

The major PL present immediately after immersion were phosphatidyl ethanolamine (PE), phosphatidyl choline (PC) and phosphatidyl inositol (PI). During germination under both conditions, light and dark, PE in cotyledons decreased with PC or PI, while phosphatidic acid increased rapidly, and phosphatidyl glycerol and diphosphatidyl glycerol also increased slightly. These changes in glycolipid and phospholipid compositions during germination seem to occur from the formation of photosynthetic tissues and the metabolic interconversion of phospholipids.