Envelope structure in three different L-forms ofProteus mirabilis

One A-type, stable and two different B-type, unstable L-forms were obtained from a strain ofProteus mirabilis and studied by electron microscopy and by chemical analysis for the presence of peptidoglycan. The wall of the parent bacterium is characterized by a profile of three superimposed dense lines and a content of 11.07 nmoles of muramic acid (MUR) and of 7.85 nmoles of diaminopimelic acid (DAP) per mg of dry weight. The stable, A-type L-form has completely lost the cell wall of the bacterium and is enveloped only by the plasma membrane to which very small quantities of peptidoglycan components are associated (MUR: 0.041 nmoles/mg; DAP: 0.075 nmoles/mg). The two B-type, unstable L-forms have the same wall structure in only two dense lines, but they differ in their peptidoglycan content. The first one does not contain more peptidoglycan components than the A-type, L-form (MUR: 0.022 nmoles/mg; DAP: 0.016 nmoles/mg), whereas the peptidoglycan content of the second one (MUR: 2.6 nmoles/mg; DAP: 1.65 nmoles/mg) is about one fifth of the content of muramic acid and diaminopimelic acid of the bacterial cell wall.     

Fatty acid composition in native and cultured human endothelial cells

Endothelial cells from human umbilical veins were isolated by collagenase treatment. Cells were cultured in the presence of either 20% fetal bovine serum (FBS) or 20% human serum (HS). At confluency, endothelial cell lipids were labeled with tracer concentrations of tritiated arachidonic acid, then extracted and separated into lipid subclasses by thin layer chromatography. The fatty acid composition of each lipid class was determined by glass capillary gas-liquid chromatography analysis and compared to that of cells freshly isolated from the cord (NC cells). The fatty acid compositions differed only in phospholipids. Polyunsaturated fatty acids (PFAs), arachidonic, and linoleic acids were depleted in FBS cell phospholipids and replaced by both stearic and oleic acids. No significant difference could be observed between NC cell and HS cell phospholipids. We conclude that PFAs might be decreased in FBS cells because of the relative paucity of PFAs in FBS as compared to HS. It seems therefore more convenient to cultivate endothelial cells in the presence of HS, especially in respect to their phospholipid content of arachidonic acid, which is the physiological reservoir for prostacyclin synthesis.     

Fatty acid composition in native and cultured human endothelial cells

Summary Endothelial cells from human umbilical veins were isolated by collagenase treatment. Cells were cultured in the presence of either 20% fetal bovine serum (FBS) or 20% human serum (HS). At confluency, endothelial cell lipids were labeled with tracer concentrations of tritiated arachidonic acid, then extracted and separated into lipid subclasses by thin layer chromatography. The fatty acid composition of each lipid class was determined by glass capillary gas-liquid chromatography analysis and compared to that of cells freshly isolated from the cord (NC cells). The fatty acid compositions differed only in phospholipids. Polyunsaturated fatty acids (PFAs), arachidonic, and linoleic acids were depleted in FBS cell phospholipids and replaced by both stearic and oleic acids. No significant difference could be observed between NC cell and HS cell phospholipids. We conclude that PFAs might be decreased in FBS cells because of the relative paucity of PFAs in FBS as compared to HS. It seems therefore more convenient to cultivate endothelial cells in the presence of HS, especially in respect to their phospholipid content of arachidonic acid, which is the physiological reservoir for prostacyclin synthesis. This work was supported by a grant from the Délégation Générale à la Recherche Scientifique et Technique, Paris, France (79.7.0091).     

Fatty acid and phospholipid composition of five psychrotrophic Pseudomonas spp. grown at different temperatures

The free fatty acid and phospholipid composition of 5 psychrotrophic marine Pseudomonas spp. have been determined in chemostat culture with glucose as the limiting substrate over the range 0–20°C. The predominant fatty acid present in all the isolates was hexadecenoic acid (C16:1) together with lesser quantities of octadecenoic acid (C 18:1) whilst none contained acids with chain lengths exceeding 18 carbon atoms. Decreasing the growth temperature from 20°C to 0°C resulted in little significant change in fatty acid composition. The principal phospholipid components of the five psychrotrophic pseudomonads have been identified as phosphatidylserine, phosphatidylglycerol, phosphatidylethanolamine and diphosphatidylglycerol. Decreasing the growth temperature did not elicit significant changes either in the total quantities of phospholipid synthesized or in the concentration of individual phospholipid components in any of the isolates. All the psychrotrophs showed maximum glucose uptake between 15°C and 20°C and the rate decreased rapidly as the temperature was decreased towards 0°C.Abbreviations PS Phosphatidylserine - PE phosphatidylethanolamine - PG phosphatidylglycerol - DPG diphosphatidylglycerol     

The chemical composition of the membranes of protoplasts and L-forms of Staphylococcus

Membrane fractions were prepared from Staphylococcus aureus H and 100 after dissolution of the cell walls by a lytic enzyme from Streptomyces griseus. Membranes were also prepared from the L-forms derived from the same strains. The membranes were analysed for protein, lipid, carbohydrate and RNA contents, and the fatty acid composition of the lipids was determined. A branched-chain saturated C(15) acid was the major component in all samples, and the correspondence between L-forms and parent bacteria was fairly close. The lipids were separated into non-polar-lipid, glycolipid and phospholipid fractions; the L-forms contained a little more neutral lipid and much more glycolipid than the parent bacteria. In all membranes the glycolipid, which accounted for all the carbohydrate present, was a diglucosyl diglyceride. The major phospholipids of the protoplast membranes were phosphatidylglycerol and some lipoamino acids (lysine and a little alanine). On the other hand, diphosphatidylglycerol was the chief phospholipid found in L-form membranes.     

Fatty acid composition of wild and cultured northern pike (Esox lucius)

The aim of the study was to determine the effect of diet on the fatty acids composition of cultured northern pike (Esox lucius) fillet (mean body weight, 620 g; age, 2.5 years; commercial feed) profiles when compared with wild pike caught in Lake Dga? Wielki in northern Poland (mean body weight, 570 g; age 3.5 years). Cultured pike fillets contained several times more fat (2.40%) compared with wild fish (0.19%, P < 0.01). The total relative quantity of saturated fatty acids (SFA; % of total fatty acids) and unsaturated fatty acids (USFA) in cultured and wild pike were similar. Monounsaturated fatty acids (MUFA) and polyunsaturated fatty acids (PUFA) content differed in wild and cultured fish. Cultured pike contained nearly two times more MUFA (30.90% compared with 15.97%; P < 0.01) but less PUFA (42.04% compared with 58.33%; P < 0.01), n‐3 PUFA (32.42% compared with 41.26%; P < 0.01), and n‐6 PUFA (6.47% compared with 15.79%; P < 0.01). The largest differences were noted with regard to docosahexaenoic acid (DHA) and arachidonic acid (AA), the levels of which in cultured and wild pike were 18.93% vs 27.96% and 0.73% vs 8.60%, respectively (P < 0.01). Quality compositions of the commercial feed and the cultured pike fillets were identical.     

Fatty acid composition of different serum phospholipids in men and women

1. Eight young healthy persons, four men and four women, were maintained for a total of 2 months on a diet in which 40%, 16% and 44% of the total calories were present as fats, proteins and carbohydrates respectively. The ratio of complex to simple carbohydrates in the diet was 1:4. 2. The fatty acids of serum kephalins, lecithins, lysolecithins and sphingomyelins were determined by gas-liquid column chromatography. 3. Lysolecithins in both men and women had the highest content of saturated acids, followed by sphingomyelins, lecithins and kephalins in that order. The degrees of saturation and of polyunsaturation of the fatty acids in the different phospholipid fractions were significantly different, except for the differences in the polyunsaturation of the kephalins and lecithins. 4. No sex difference was found in the fatty acid composition of the different phospholipids.     

Fatty acid composition in fetal, neonatal, and cultured cardiomyocytes in rats

Reconstructed myocardial tissue still does not have enough pulsatile contraction. It is well known that fetal and mature neonatal cardiomyocytes utilize glucose and lipid, respectively, as their energy substrates, and that cultured ones mainly use glucose in spite of their age comparable to neonate ones, probably due to insufficient supply of lipids from culture medium. In the present study, we compared 7 saturated, 6 monounsaturated, and 11 polyunsaturated fatty acid contents in cultured cardiomyocytes (Cul group) with those in fetal (Fet group, approximately 17 d after impregnation) and neonatal (Neo group, 9 d old) rats, where the age of the Cul cells were set nearly equal to the Neo ones. Saturated fatty acid contents in the Cul group were generally lower than those in the Fet group and were close to those in the Neo group, except for C12:0 of which content was highest in the Neo group. Monounsaturated fatty acid contents in the Cul group were generally lower than those in the Fet group but similar to or higher than those in the Neo group, except for C24:1n-9 of which content was again highest in the Neo group. In contrast, most of polyunsaturated fatty acid (PUFA) contents in the Cul group appeared lower than those in both the Fet and Neo groups, and differences in 5 of 10 detected PUFAs were significant between the Cul and Neo groups. The results suggest that PUFA contents in cultured cardiomyocytes might be insufficient to exert enough contractile ability. In conclusion, it could be necessary for cultured cardiomyocytes to uptake more lipid; PUFAs in particular.     

Fatty acid composition of Ruditapes decussatus spat fed on different microalgae diets

The fatty acid composition of the Ruditapes decussatus spat fed on three different microalgal diets during 4 weeks was determined. The fatty acid pattern of each diet was also analysed. The diets used were Isochrysis galbana, clone T-ISO, Tetraselmis suecica, and Phaeodactylum tricornutum. The fatty acid composition of the spat was usually well correlated with that of the diet supplied. Major differences among spat cultures were found in 14:0, 16:0, 16:1n-9, 16:1n-7, 18:1n-9, 18:2n-6, 18:3n-3, 18:4n-3, 20:5n-3, 22:5n-6 and 22:6n-3 fatty acids. These differences were correlated with the particular fatty acid content of each diet supplied. It has been shown that R. decussatus spat have a very low capacity to elongate and desaturate linolenic acid to n-3 PUFA, so when 20:5n-3 or 22:6n-3 were not present in the diet, they were also absent, at least in measurable amounts, in the clams. The absence of any of the “essential” fatty acids, 20:5n-3 in T-ISO or 22:6n-3 in Tetraselmis, did not limit spat growth, so their role as “essential” fatty acids might be a matter for discussion. Finally, the nutritive value of each diet was discussed in terms of its fatty acid composition.     

Fatty acid composition of lipids from the vacuolar membranes of the roots of root vegetables

The fatty acid (FA) composition of vacuolar membrane lipids from the storage tissues of parsnip (Pastinaca sativa L.), parsley (Petroselinum crispum L.), and carrot (Daucus carota L.) was studied by gasliquid chromatography, and possible pathways of the biosynthesis of these acids are considered. A high level of unsaturated FAs (up to 78% of the total FA amount) was characteristic of these membrane lipids with the predominance of linoleic acid, which content in vacuolar lipids of parsnip, parsley, and carrot was 53.5, 55.1, and 54.4%, respectively. A high content of hexadienoic acid (C16:2ω6) was characteristic of the vacuolar lipids of parsnip and parsley (8.0 and 4.6%. respectively); the content of α-linolenic acid in the vacuolar lipids of these plants was 4.4–7.3%. Palmitic acid predominated among the saturated FAs (18.0–20.4%).     

Fatty acid composition of Simonsiella strains

Gas-liquid chromatography of methyl esters of bound fatty acids extracted from the cells of 48 Simonsiella strains showed that these aerobic, gliding, multicellular-filamentous bacteria have fatty acid profiles of the pattern considered typical of Gramnegative eubacteria. All strains contained predominantly tetradecanoic acid (29.5%), 9-hexadecenoic acid (22.2%), an unidentified acid with an equivalent chain length of approximately 20 carbon atoms (15.8%), and dodecanoic acid (11.4%).Discriminant analysis of the mean relative percentages of 12 fatty acids correctly assigned 94% of the strains to groups based on their source of origin (i.e., the oral cavities of sheep, cat, human or dog); the relative amounts of only 3 of the fatty acids (9-octadecenoic acid, hexadecanoic acid, and tetradecanoic acid) provided most of this discrimination.     

Fatty acid composition of lipopolysaccharides of the strains of different species of Yersinia

The fatty acid composition of lipopolysaccharides of the strains of Y. enterocolitica, Y. intermedia, Y. frederiksenii and Y. ruckeri studied during cultivation on meat-peptone agar is characterized by the predominance of 3-hydroxytetradecanoic and dodecanoic acids. Closely related to the mentioned bacteria is the strain of Y. kristensenii which is distinguished only by its higher level of hexadecanoic acid. The strains of Y. pseudotuberculosis and the vaccine strain of Y. pestis have a uniform fatty acid composition of lipopolysaccharides with predominance of 3-hydroxytetradecanoic acid. Their relatively low level of dodecanoic acid conditions the characteristic fatty acid spectrum of lipopolysaccharides which differs from that of the above mentioned group of Yersinia. The peculiarities of the fatty acid composition of lipopolysaccharides of both groups of Yersinia are preserved during growth on meat-peptone broth, but the increase in the level of hexadecanoic acid balances the differences between Y. kristensenii, the other Y. enterocolitica-like bacteria and Y. ruckeri. The obtained results confirm close relationship of Y. pseudotuberculosis and Y. pestis, and also of Y. enterocolitica and Y. enterocolitica-like bacteria, showing propinquity of Y. ruckeri to the latter.     

Fatty acid composition of apical and basolateral enterocyte membranes of the small intestine of the gopher

Fatty acid composition of gopher's (Citellus suslicus G.) small intestine apical and basolateral membranes of enterocytes has been investigated. The content of eight fatty acids: C12:0, C14:0, C15:0, C16:0, C17:0, C18:0, C16:1, C18:1 has been obtained.     

Fatty acid composition of Rhizobium spp.

The fatty acid composition of 42 isolates belonging to the major plant affinity groups of Rhizobium has been determined and found to vary reproducible with culture age. Numerical taxonomic techniques applied to the 15 major fatty acid components of log-phase cultures of comparable physiological age showed that the rhizobia constitute a uniform group. However, two clusters comprising soybean-cowpea isolates and pea-bean isolates were evident. These observations, based on a simple analysis of only one group of chemical components, indicate relationships among rhizobia which differ from the conventional plant-affinity groupings but which are consistent with other proposed relationships established using a variety of biochemical and physiological criteria.