Lipid Molecular Species of Lipomyces starkeyi

The molecular species of glycerides and phospholipids of the yeast Lipomyces starkeyi IFO 0678 harvested at 60 hr, corresponding to the late exponential phase, were analyzed by gas chromatography-mass spectrometry. The major triglyceride was C_16:0–C_18:1–C_18:1. The major molecular species of phospholipid were 1–C_16:0–2–C_18:1 and 1–C_18:1–2–C_18:2. Although phosphatidylcholine and phosphatidylethanol amine were composed of several kinds of molecular species, 1–C_16:1–2–C_18:1, 1–C_18:1–2–C_18:2 and l-C_16:0–2–C_18:1, phosphatidylserine was composed of almost exclusively 1–C_16:0-2-C_18:1. The lipid and the fatty acid compositions of the yeast harvested at the different growth phases were also investigated.     

Effect of cultural conditions on the lipid profile of Thiobacillus ferroxidas

The intensitive investigations on the lipid profile of Thiobacillus ferrooxidans at various culture ages suggest some correlations of the lipid constitutents with the membrane-bound iron oxidation system. Phosphatidic acid, phosphatidyl serine and phosphatidyl ethanolamine were the major polar components; hydrocarbon, triglyceride and diglyceride were the main neutral components. Major fatty acids were C_16:0, C_16:1, C_16:3, C_18:1, C_18:3, C_22:1 while C_20:1, C_20:2, C_12:0, C_14:2, C_18:0, C_18:2, C_20:0, C_22:0 were found in trace amounts which also depended upon the phase of the growth. One lipoamino acid was identified as ornithine lipid in the polar fraction. Each and every component varied to some extent at different growth phasesindicating relationship of these lipids to the iron oxidation system of the strain.     

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.

     

Variations in the Lipid Compositions and in the Lipid Molecular Species of Lipomyces starkeyi Cultivated in the Glucose Sufficient and the Glucose Deficient Media

The lipid compositions, fatty acid compositions, positional distributions of fatty acids in glycerides, and molecular species of phospholipids of L. starkeyi, cultured in the glucose sufficient and the glucose deficient media were compared.

Under the glucose sufficient condition, the triglyceride content increased, accompanied by the remarkable increase of C_16:0–C_18:1–C_18:0. The phospholipid content also increased with the variations of the compositions of molecular species in phosphatidylethanolamine and phosphatidylcholine.

Under the glucose deficient condition, the triglyceride content remarkably decreased, especially in C_18:1–C_18:1–C_18:1. The compositions of phospholipid molecular species were considerably different from those of the glucose sufficient condition.     

Identification of the alga known as <Emphasis Type="Italic">Nannochloropsis</Emphasis> Z-1 isolated from a prawn farm in Hainan,China as <Emphasis Type="Italic">Chlorella</Emphasis>

An alga known as “Nannochloropsis”, isolated from a prawn farm in Hainan, China, has been critically investigated and identified as Chlorella, a member of the Chlorophyceae based on fatty acid composition, ultrastructure, and 18S rDNA. Cells of this alga were spherical, measured by 1–6 μm in diameter and were enclosed in thin walls of approximately 0.04 μm thickness. They contained several small mitochondria, two to three thylakoids and had no vacuoles. There were many pyrenoids in the algal cells and their thylakoid lamellae were sparse and not translucent. Many lipid droplets were present in the cytoplasm. The total lipid content of this alga was 3% per gram dry weight and its major fatty acids were C_16:0, C_18:0, C_18:1, C_18:2, C_18:3 and C_20:0. Eicosapentaenoic acid (C_20:5, EPA) was not detected. The length of its 18S rDNA sequence was 1,712 bp. 18S rDNA sequence analyses indicated that this alga was a species of Chlorella.     

Some variations in the composition of suberin from the cork layers of higher plants

The monomeric composition of the suberins from 16 species of higher plants was determined by chromatographic methods following depolymerization of the isolated extractive-free cork layers with sodium methoxide-methanol. 1-Alkanols (mainly C₁₈C₂₈), alkanoic (mainly C₁₆C₃₀), α,ω-alkanedioic (mainly C₁₆C24), ω-hydroxyalkanoic (mainly C₁₆C₂₁), dihydroxyhexadecanoic (mainly 10,16-dihydroxy- and 16-dihydroxyhexadecanoic), monohydroxyepoxyalkanoic (9,10-epoxy-18-hydroxyoctadecanoic), trihydroxyalkanoic (9,10, 18-trihydroxyoctadecanoic), epoxyalkanedioic (9,10-epoxyoctadecane-1,18-dioic) and dihydroxyalkanedioic (9,10-dihydroxyoctadecane-1 18-dioic) acids were detected in all species. The suberins differed from one another mainly in the relative proportions of these monomer classes and in the homologue content of their 1-alkanol, alkanoic, α,ω-alkanedioic and ω-hydroxyalkanoic acid fractions. C₁₈ epoxy and vic-diol monomers were major components (32–59%) of half of the suberins examined (Quercus robur, Q. ilex, Q. suber, Fagus sylvatica, Castanea sativa, Betula pendula, Acer griseum, Fraxinus excelsior) where as ω-hydroxyalkanoic and α,ω-alkanedioic acids predominated in those that contained smaller quantities of such polar C₁₈ monomers (Acer pseudoplatanus, Ribes nigrum, Euonymus alatus, Populus tremula, Solanum tuberosum, Sambucus nigra, Laburnum anagyroides, Cupressus leylandii). All species, however, contained substantial amounts (14–55 %) of ω-hydroxyalkanoic acids, the most common homologues being 18:1 (9) and 22: 0. The dominant α,ω-alkanedioic acid homologues were 16: 0 and 18: 1 (9) whereas 22: 0, 24: 0 and 26: 0, and 20: 0, 22: 0 and 24: 0 were usually the principal homologues in the 1-alkanol and alkanoic acid fractions, respectively. The most diagnostic feature of the suberins examined was the presence of monomers greater than C₁₈ in chain length; most of the C₁₆ and C₁₈ monomers identified in the suberins also occur in plant cutins emphasizing the close chemical similarity between the two anatomical groups of lipid biopolymer.     

Fatty acids in green algae cultivated on a pilot-plant scale

Fatty acids fromChlorella vulgaris, Scenedesmus obliquus var.acutus and from a mixed culture of the two strains, Melnik, were converted to methyl esters, separated by gas chromatography, and identified by means of standards. The spectrum of fatty acids included both saturated and unsaturated acids (with odd and even numbers of carbon atoms) from C₁₂ to C₂₂. Fatty acids C_16:0, C_18:0 and C_20:3 were the major components in all cultures. Pure strains differed from the mixed culture in the production of C_18:1, C_12:0 and C_19:2 acids; the first of these was present in higher amounts in pure cultures only, the latter two being found in the mixed culture. The level of lipids was lower as compared to the literature data and their extractability was affected by the manner of preparation of algae and extraction conditions.     

Effect of fasting on the composition of the fat body lipid of Dipetalogaster maximus, Triatoma infestans and Panstrongylus megistus (Hemiptera: Reduviidae)

Modifications in content and lipid composition induced by fasting were examined in fat bodies from adults of Triatominae, Dipetalogaster maximus, Triatoma infestans and Panstrongylus megistus. With fasting, total lipid stores dropped approximately 50% for T. infestans and more than 70% for P. megistus. Total lipids analyzed by thin layer chromatography and fractionated by column chromatography on Unisil showed triacylglycerols as the main component in the three species, although P. megistus showed high levels of diacylglycerols (31–46%). Cholesterol amounted to 8–15%. In diacylglycerol fractions, C_16:0, C_18:1 and C_18:0 fatty acids were detected; their ratio varied with species but it was not dependent on nutritional status. In triacylglycerol fractions C_18:1 fatty acid was the major component at different times (48–68%); the ratio of monounsaturated to saturated in this fraction was 1.3, 2.6 and 1.2 for D. maximus, T. infestans and P. megistus respectively. The remarkable drop in lipid stores without noticeable changes in their relative composition would suggest that all types of lipid are used at similar rates. The higher content of diacylglycerols in P. megistus may be associated with the better flight performance of this species. Accepted: 4 August 1998     

Fatty acids of monogalactosyl diglycerides from Citrus

Fatty acids in vesicular and leaf monogalactosyl diglycerides (MGDG) of citrus were studied. Vesicular MGDG contained front 94.4 to 97.3% C₁₆, C_16:1, C_18:1, C_18:2, and C_18:3; whereas leaf MGDG contained ca 90% C_18:3, 3% C₁₆ and 1.8 to 9.5% C_18:2. Species varied considerably in their percentages of vesicular C_18:2, C1_8:3 and to a lesser degree, C_16:1 and C_18:1 fatty acids with lemons being the most distinctive. Branched fatty acids were present to the extent of 5.6% in vesicular and to only 0.1% in leaf MGDG.     

Profiles of photosynthetic glycerolipids in three strains of <Emphasis Type="Italic">Skeletonema</Emphasis> determined by UPLC-Q-TOF-MS

An exhaustive qualitative and quantitative profiling of the photosynthetic glycerolipids in three strains of the marine diatom Skeletonema sp. was carried out by ultra performance liquid chromatography-electrospray ionization-quadrupole-time of flight-mass spectrometry. In the diatom thylakoid membrane, monogalactosyldiacylglycerol (MGDG) and digalactosyldiacylglycerol (DGDG) account for about 45–70% and 5–15% of the total membrane lipids, respectively. The anionic sulfoquinovosyldiacylglycerol (SQDG) as well as the likewise anionic phosphatidylglycerol (PG) contribute between 10–40% and 4–10% each. The predominant species of MGDG were those with C_16:3/C_16:3, C_20:5/_16:1, and C_20:5/C_16:3. Three main molecular species of DGDG contained C_20:5/C_16:1, C_20:5/C_16:2, and C_16:1/C_16:1. The major molecular species of SQDG were those containing combinations of C_14:0/C_14:0, C_14:0/C_16:0, C_14:0/C_16:1, and C_14:0/C_16:3. All the PG classes contained the C_18:1/C_18:1 as the main molecular species. Based on the fatty acid species in sn-2 position, it is indicated that MGDG and DGDG are biosynthesized through prokaryotic pathway exclusively within the chloroplast, whereas PG and SQDG have a typical mixed biosynthetic pathway (both prokaryotic pathway and eukaryotic pathways). The chemical characteristics of photosynthetic glycerolipids related with ecological physiology are discussed.     

Biomass production,total protein,chlorophylls, lipids and fatty acids of freshwater green and blue-green algae under different nitrogen regimes

Two green algae (Chlorella vulgaris and Scenedesmus obliquus) and four blue-green algae (Anacystis nidulans, Microcystis aeruginosa, Oscillatoria rubescens and Spirulina platensis) were grown in 81 batch cultures at different nitrogen levels. In all the algae increasing N levels led to an increase in the biomass (from 8 to 450 mg/l), in protein content (from 8 to 54 %) and in chlorophyll. At low N levels, the green algae contained a high percentage of total lipids (45 % of the biomass). More than 70 % of these were neutral lipids such as triacylglycerols (containing mainly 16:0 and 18:1 fatty acids) and trace amounts of hydrocarbons. At high N levels, the percentage of total lipids dropped to about 20 % of the dry weight. In the latter case the predominant lipids were polar lipids containing polyunsaturated C₁₆ and C₁₈ fatty acids. The blue-green algae, however, did not show any significant changes in their fatty acid and lipid compositions, when the nitrogen concentrations in the nutrient medium were varied. Thus the green but not the blue-green algae can be manipulated in mass cultures to yield a biomass with desired fatty acid and lipid compositions. The data may indicate a hitherto unrecognized distinction between prokaryotic and eukaryotic organisms.     

Rapid determination of lipids in healthy human lymphocytes

Lipids of human lymphocytes were determined from 20 ml of heparinized peripheral blood using thin-layer chromatography with a flame ionization detector, and gas chromatography.The weight per cent and μg per 10⁶ lymphocytes for cholesterol ester, triglyceride, free cholesterol and phospholipid were 11.1 and 5.2, 18.1 and 17.9, 15.1 and 8.5, and 55.7 and 44.2, respectively. Phospholipid was the major lipid component in human lymphocytes. Phospholipid was subfractionated into phosphatidylethanolamine, phosphatidylinositol plus phosphatidylserine, phosphatidylcholine and sphingomyelin in amounts of 25.2, 6.1, 46.9 and 22.9%, respectively.Total fatty acid composition was analyzed as: C_14:0, 13.3%; C_16:0, 20.9%; C_16:1, 6.5%; C_18:0, 19.6%; C_18:1, 18.8%; C_18:2, 7.1%; and C_20:4, 12.3%. Higher cholesterol ester and triglyceride and lower C_14:0 were characteristic of female lymphocytes when compared with male lymphocytes.The lipid composition quantitated by this method corresponded well with previously reported data.Thus, this method can be used clinically because of its simplicity and higher sensitivity.     

Changes of Lipid Composition with Growth Phase of Cryptococcus neoformans

Qualitative and quantitative profiles of phospholipids, neutral lipids, and fatty acid composition in Cr. neoformans during the growth phase were investigated in relation to pyrophosphatidic acid. A marked increase of the total lipid content, which depended on the accumulation of triglyceride in yeast cells with the growth, was observed. The total phospholipid contents in yeast cells remained almostly constant during the exponential phase and slightly decreased in the stationary phase. The major phospholipids of this yeast were phosphatidylcholine, phosphatidylethanolamine, phosphatidylinositol, phosphatidylserine, and cardiolipin, the next groups being pyrophosphatidic acid, phosphatidic acid, lysophos-phatidylcholine, and unidentified components. The amounts of phosphatidylcholine, phosphatidylinositol, and cardiolipin were fairly constant throughout the growth phase, but the amount of phosphatidylethanolamine increased and that of phosphatidylserine decreased with progressive growth. The pyrophosphatidic acid contents were 0.9~0.7% for total phospholipid during the growth phase. The major fatty acids of pyrophosphatidic acid were C_16:0, C_18:1, and C_18:2 acids. The changing patterns of fatty acid composition in pyrophosphatidic acid through the growth phase closely resembled that of phosphatidic acid, which contained larger amounts of C_18:1 acid (35~45%) than C_16:0 acid (30~25%) and C_18:2 acid (30~25%). Phosphatidylserine and phosphatidylinositol contained considerable amounts of saturated fatty acid (C_16:0 acid, more than 55%). On the other hand, phosphatidylcholine, phosphatidylethanolamine, and cardiolipin contained extremely large amounts of unsaturated fatty acid (C_18:1 and C_18:2 acid, 85ç90%).     

Neiella holothuriorum sp. nov., isolated from the gut of a sea cucumber Apostichopus japonicus

A Gram-stain negative, aerobic, rod-shaped bacterium, designated 126^T, was isolated from the intestinal content of a sea cucumber, Apostichopus japonicus, in China. Strain 126^T was found to grow optimally at 25–28 °C and pH 7.5–8.0 in marine 2216 E medium, with tolerance of 1–7% (w/v) NaCl. Strain 126^T is motile by means of one to several polar flagella. The dominant fatty acids of strain 126^T were identified as C_16:1 ω7c/C_16:1 ω6c (29.5%), C_18:1 ω7c/C_18:1 ω6c (19.8%) and C_16:0 (16.7%). The respiratory quinone was found to be Q-8. The polar lipid profile was found to be mainly composed of phosphatidylglycerol and phosphatidylethanolamine. The total length of the draft genome is approximately 4.2?×?10⁶ bp, encoding 3655 genes and 3576 coding sequences. The G?+?C content of the genomic DNA is 48.0%. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain 126^T belongs to the genus Neiella and is closely related to Neiella marina J221^T (96.5%). Genomic comparisons of 126^T to N. marina J221^T revealed that they had similar genome size, G?+?C content and complement of clusters of orthologous groups. However, average nucleotide identity and digital DNA–DNA hybridization values between strains126^T and N. marina J221^T was 75.5% and 19.7%, which could distinguish the strains. On the basis of these phenotypic and genotypic data, strain 126^T is concluded to represent a novel species, for which the name Neiella holothuriorum sp. nov. is proposed. The type strain is 126^T (=?GDMCC 1.2530^T?=?KCTC 82829^T).

     

Overexpression of malic enzyme (ME) of Mucor circinelloides improved lipid accumulation in engineered Rhodotorula glutinis

The oleaginous yeast Rhodotorula glutinis has been known to be a potential feedstock for lipid production. In the present study, we investigated the enhancement of expression of malic enzyme (ME; NADP⁺ dependent; EC 1.1.1.40) from Mucor circinelloides as a strategy to improve lipid content inside the yeast cells. The 26S rDNA and 5.8S rDNA gene fragments isolated from Rhodotorula glutinis were used for homologous integration of ME gene into R. glutinis chromosome under the control of the constitutively highly expressed gene phosphoglycerate kinase 1 to achieve stable expression. We demonstrated that by increasing the expression of the foreign ME gene in R. glutinis, we successfully improved the lipid content by more than twofold. At the end of lipid accumulation phrase (96 h) in the transformants, activity of ME was increased by twofold and lipid content of the yeast cells was increased from 18.74 % of the biomass to 39.35 %. Simultaneously, there were no significant differences in fatty acid profiles between the wild-type strain and the recombinant strain. Over 94 % of total fatty acids were C_16:0, C_18:0, C_16:1, C_18:1, and C_18:2. Our results indicated that heterologous expression of NADP⁺-dependent ME involved in fatty acid biosynthesis indeed increased the lipid accumulation in the oleaginous yeast R. glutinis.     

Decrease in sunflower (Helianthus annuus) seed viability caused by high temperature as related to energy metabolism, membrane damage and lipid composition

The aim of the present work was to investigate whether loss of germination ability and viability of sunflower (Helianthus annuus L.) seeds during incubation at a high temperature (45°C) was related to changes in energy metabolism, loss of membrane integrity, and/or changes in lipid composition. Pre‐treatment of seeds at 45°C progressively reduced subsequent germination at the optimal temperature (25°C). Seeds did not germinate at 45°C and almost all of them were dead after 72 h of soaking at this high temperature. This loss of seed viability was associated with a large increase in leakage of K⁺ and total electrolytes into the incubation medium, and with production of malondialdehyde in the embryonic axis and cotyledons, suggesting a loss of membrane integrity probably due to lipid peroxidation. ATP and ADP levels increased sharply during the first hours of imbibition at 45°C, remained high for about 24 h and then decreased. As a consequence, the energy charge followed a similar pattern. If the treatment at 45°C did not exceed 48 h, seeds recovered an apparently normal energy metabolism after transfer to 25°C, even though they lost their ability to germinate at this temperature. Therefore, energy metabolism at the whole embryo level cannot be considered as an indicator of germination ability. Incubation of seeds at 45°C resulted in an increase in triacylglycerols and diacylglycerols without a significant change in their fatty acid composition. It also induced a slight increase in phospholipid content with an increase in C_16:0, C_18:0 and C_18:1, but with no change in C_18:2. In phospholipids, the C_18:2/C_18:1 and (C_18:1 + C_18:2)/ (C_16:0 + C_18:0) ratios thus declined during treatment at 45°C. The results obtained suggest that deterioration of sunflower seeds during incubation at a high temperature is mainly related to membrane damage and alteration of energy metabolism, and that accumulation of malondialdehyde, which is an index of lipid peroxidation, does not correspond to a decrease in total lipids and phospholipids nor to a significant change in fatty acid composition, except in PL in which the C_18:2/C_18:1 and (C_18:1 + C_18:2)/ (C_16:0 + C_18:0) ratios slightly declined.     

Formation of biomass,total protein,chlorophylls, lipids and fatty acids in green and blue-green algae during one growth phase.

Batch cultures (8–32 l.) of Chlorella vulgaris and Scenedesmus obliquus and of Anacystis nidulans and Microcystis aeruginosa were grown in media containing 0.001 % KNO₃ and at several stages in growth sampled for biomass, total protein, chlorophylls, lipids and fatty acids. With increasing time and decreasing nitrogen concentrations, the biomass of all of the algae increased, whereas the total protein and chlorophyll content dropped. Green and blue-green algae, however, behaved differently in their lipid metabolism. In the green algae the total lipid and fatty acid content as well as the composition of these compounds changed considerably during one growth phase and was dependent on the nitrogen concentration in the media at any given day of growth. More specifically, during the initial stages of growth the green algae produced larger amounts of polar lipids and polyunsaturated C₁₆ and C₁₈ fatty acids. Towards the end of growth, however, these patterns changed in that the main lipids of the green algae were neutral with mainly saturated fatty acids (mostly 18:1 and 16:0). Such changes did not occur in the blue-green algae. These differences between prokaryotic and eukaryotic algae can possibly be explained by the ‘endosymbiont theory’.     

Oleaginous yeast Meyerozyma guilliermondii shows fermentative metabolism of sugars in the biosynthesis of ethanol and converts raw glycerol and cheese whey permeate into polyunsaturated fatty acids

We studied the biotechnological potential of the recently isolated yeast Meyerozyma guilliermondii BI281A to produce polyunsaturated fatty acids and ethanol, comparing products yields using glucose, raw glycerol from biodiesel synthesis, or whey permeate as substrates. The yeast metabolism was evaluated for different C/N ratios (100:1 and 50:1). Results found that M. guilliermondii BI281A was able to assimilate all tested substrates, and the most efficient conversion obtained was observed using raw glycerol as carbon source (C/N ratio 50:1), concerning biomass formation (5.67 g·L⁻¹) and lipid production (1.04 g·L⁻¹), representing 18% of dry cell weight. Bioreactors experiments under pH and aeration-controlled conditions were conducted. Obtained fatty acids were composed of ~67% of unsaturated fatty acids, distributed as palmitoleic acid (C_16:1, 9.4%), oleic acid (C_18:1, 47.2%), linoleic acid (C_{18:2 n−6}, 9.6%), and linolenic acid (C_{18:3 n−3}, 1.3%). Showing fermentative metabolism, which is unusual for oleaginous yeasts, M. guilliermondii produced 13.7 g·L⁻¹ of ethanol (yields of 0.27) when growing on glucose medium. These results suggest the promising use of this uncommonly studied yeast to produce unsaturated fatty acids and ethanol using cheap agro-industrial residues as substrates in bioprocess.     

Leishmania species: fatty acid composition of promastigotes

The fatty acid composition of the total lipid fractions of five different Leishmania organisms grown on Eagle's medium was determined by gas chromatography. The major fatty acids identified in the total lipid fractions of L. donovani, L. tropica major, L. tropica minor, L. tropica (England strain), and L. enriettii were C_12:0, C_13:0, C_14:0, C_15:0, C_16:0, C_17:0, C_18:0, C_18:1, C_18:2, and C_18:3. The statistical differences among the fatty acid methyl esters of different Leishmania organisms are discussed.Gas chromatographic analysis of the fatty acid methyl esters of the total lipid fractions of the original Eagle's medium and the media after harvesting of various Leishmania species revealed the presence of C_18:3 fatty acid in the total lipid fraction of the medium of L. donovani and the complete absence of 18-carbon unsaturated fatty acids in the total lipid fraction of the medium of L. enriettii. The use of such differences in the differentiation of various Leishmania species is discussed.     

Effect of cell lipid composition on the formation of nonspecific antibiotic resistance in alkanotrophic rhodococci

The antibiotic resistance and lipid composition of rhodococci grown in rich organic media with gaseous or liquidn-alkanes were studied. Hydrocarbon-grown rhodococci exhibited an increased resistance to a wide range of antibiotics (aminoglycosides, linkosamides, macrolides, β-lactams, and aromatic compounds). The enhanced antibiotic resistance of rhodococci grown onn-alkanes correlated with an increased content of total cell lipids (up to 14–28%) and saturated straight-chain fatty acids (C_16:0, C_18:0, C_21:0) and was accompanied by the appearance of cardiolipin and phosphatidylglycerol in cells. These lipid compounds are supposed to promote the formation of nonspecific antibiotic resistance in rhodococci by decreasing the permeability of their cell envelope to antibiotics.