Changes in Membrane Fatty Acid Composition of Pseudomonas aeruginosa in Response to UV-C Radiations

The changes in lipid composition enable the micro-organisms to maintain membrane functions in the face of environmental fluctuations. The relationship between membrane fatty acid composition and UV-C stress was determined for mid-exponential phase and stationary phase Pseudomonas aeruginosa. The total lipids were obtained by dichloromethane/methanol (3:1) and were quantified by GC. The TLC analysis of phospholipids showed the presence of three major fractions phosphatidylethanolamine, phosphatidylglycerol, and cardiolipin. Significant modifications, as manifested by an increase of UFA, were obtained. Interestingly, this microorganism showed a remarkable capacity for recovery from the stressful effects of UV-C.     

Effect of chronic ethanol, catalase inhibitor 3-amino-1,2,4-triazole and clofibrate treatment on lipid peroxidation in rat myocardium

1. The effect of chronic alcohol consumption, catalase inhibitor 3-amino-1,2,4-triazole (amino-triazole) and peroxisome proliferator clofibrate on the level of Fe/ADP-ascorbate-induced lipid peroxidation has been studied in the rat myocardium. The intensity of lipid peroxidation was measured using chemiluminescence technique and malondialdehyde formation. 2. Combined us well as separate treatment with ethanol (36% of dietary calories) and aminotriazole caused elevation of the rate of lipid peroxidation in the nuclear-free homogenate or total particulate fraction of the rat heart. The most pronounced effect was noted during combined application of ethanol and aminotriazole. 3. Prolonged clofibrate treatment significantly increased the level of nonenzymatic lipid peroxidation in the rat myocardium. 4. Peroxidative alteration of the myocardial lipids in vivo was evaluated by measurement of conjugated dienes (absorbance at 233 nm). Separate ethanol, aminotriazole or clofibrate treatment did not affect the level of u.v. absorption of lipids from the total particulate fraction. However, when ethanol and aminotriazole were administered simultaneously an increase of conjugated diene formation was observed. 5. The data obtained confirm the hypothesis that ethanol or clofibrate-induced activation of the myocardial lipid peroxidation may be due to the increase of hydrogen peroxide-generating capacity of the heart microperoxisomes.     

News & Notes: The Effect of Ethanol and Oxygen on the Growth of Zymomonas mobilis and the Levels of Hopanoids and Other Membrane Lipids

Zymomonas mobilis (ATCC 29191) was grown either aerobically or anaerobically in the presence of 2% (wt/vol) glucose and 0, 3, or 6% (vol/vol) ethanol. The rates of growth and the composition of hopanoids, cellular fatty acids, and other lipids in the bacterial membranes were quantitatively analyzed. The bacterium grew in the presence of 3% and 6% ethanol and was more ethanol tolerant when grown anaerobically. In the absence of ethanol, hopanoids comprised about 30% (by mass) of the total cellular lipids. Addition of ethanol to the media caused complex changes in the levels of hopanoids and other lipids. However, there was not a significant increase in any of the hopanoid lipid classes as ethanol concentration was increased. As previously reported, vaccenic acid was the most abundant fatty acid in the lipids of Z. mobilis, and its high constitutive levels were unaffected by the variations in ethanol and oxygen concentrations. A cyclopropane fatty acid accounted for 2.6–6.4 wt % of the total fatty acids in all treatments. Received: 12 November 1996 / Accepted: 25 February 1997     

Assessment of bacterial acyltransferases for an efficient lipid production in metabolically engineered strains of E. coli

Microbially produced lipids like triacylglycerols or fatty acid ethyl esters are currently of great interest as fuel replacements or other industrially relevant compounds. They can even be produced by non-oleaginous microbes, like Escherichia coli, upon metabolic engineering. However, there is still much room for improvement regarding the yield for a competitive microbial production of lipids or biofuels. We genetically engineered E. coli by expressing fadD, fadR, pgpB, plsB and ‘tesA in combination with atfA from Acinetobacter baylyi. A total fatty acid contents of up to 16% (w/w) was obtained on complex media, corresponding to approximately 9% (w/w) triacylglycerols and representing the highest titers of fatty acids and triacylglycerols obtained in E. coli under comparable cultivation conditions, so far. To evaluate further possibilities for an optimization of lipid production, ten promising bacterial wax ester synthase/acyl-Coenzyme A:diacylglycerol acyltransferases were tested and compared. While highest triacylglycerol storage was achieved with AtfA, the mutated variant AtfA-G355I turned out to be most suitable for fatty acid ethyl ester biosynthesis and enabled an accumulation of approx. 500 mg/L without external ethanol supplementation.     

Extraction of lipids and pigments of Chlorella vulgaris by supercritical carbon dioxide: influence of bead milling on extraction performance

The influence of bead milling on the extraction of lipids and pigments by supercritical carbon dioxide was investigated in this study. Different operating parameters for the 3-h process were first tested on raw Chlorella vulgaris; 600 bar was the optimum pressure at 60 °C with a carbon dioxide flow rate of 30 g min^?1. Under these operating conditions, 10 % of total lipid containing chlorophyll and carotenoids with 1.61 and 1.72 mg g^?1 dry weight of microalga, respectively, has been recovered. Microscopic observation was used to assess a cell wall breakage through bead milling, which produced positive results in terms of increasing the yield of biomolecules of interest. Thus, under the same operating conditions, the yield of total lipid extract, chlorophyll and carotenoids increased significantly. Moreover, the addition of a polar co-solvent to a raw microalga had a considerable effect on the final extract. Overall, the addition of 5 % w v^?1 ethanol to a raw microalga increased the total extract yield by 27 %, and bead milling increased the total extract yield by 16 %. Chlorophyll and carotenoids were also significantly affected by the addition of ethanol, with an 81 and 65 % increase with a raw microalga and a 61 and 52 % increase using bead milling, respectively.     

Diet Composition and Lipids of In Vitro-Produced Heterorhabditis bacteriophora

Several entomopathogenic nematode species are currently under evaluation for mass production and field efficacy for biological control of insect pests. However, quality and quantity of in vitro-produced entomopathogenic nematodes vary considerably, depending on media, temperature, and production method. In addition, nematode production should be cost effective. We investigated nematode yield, production time, total lipid content, and fatty acid composition of Heterorhabditis bacteriophora produced in artificial media supplemented with different lipid sources. Lipid source significantly affected lipid quantity and quality in H. bacteriophora. Media supplemented with extractable insect lipids produced yields 1.9 times higher than did beef fat- or lard-supplemented media. Moreover, the developmental rate in media supplemented with host lipids was 1.7 times faster than that in media supplemented with beef fat or lard. Nematodes grown in media supplemented with insect lipids accumulated significantly higher lipid proportion per dry biomass than those grown in media supplemented with other lipid sources. H. bacteriophora produced in media supplemented with insect lipids, olive oil, or canola oil had similar fatty acid patterns, with oleic (18:1) acid as the major lipid fatty acid. Media supplemented with other lipid sources produced nematodes with fatty acid patterns different from those of media supplemented with insect lipids. We recommend addition of fatty acid mixtures that resemble natural host lipids for mass-producing entomopathogenic nematodes. This could provide nematode quality similar to in vivo-produced nematodes and could improve yield.     

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.     

Towards the Industrial Production of Omega-3 Long Chain Polyunsaturated Fatty Acids from a Genetically Modified Diatom Phaeodactylum tricornutum

The marine diatom Phaeodactylum tricornutum can accumulate up to 30% of the omega-3 long chain polyunsaturated fatty acid (LC-PUFA) eicosapentaenoic acid (EPA) and, as such, is considered a good source for the industrial production of EPA. However, P. tricornutum does not naturally accumulate significant levels of the more valuable omega-3 LC-PUFA docosahexaenoic acid (DHA). Previously, we have engineered P. tricornutum to accumulate elevated levels of DHA and docosapentaenoic acid (DPA) by overexpressing heterologous genes encoding enzyme activities of the LC-PUFA biosynthetic pathway. Here, the transgenic strain Pt_Elo5 has been investigated for the scalable production of EPA and DHA. Studies have been performed at the laboratory scale on the cultures growing in up to 1 L flasks a 3.5 L bubble column, a 550 L closed photobioreactor and a 1250 L raceway pond with artificial illumination. Detailed studies were carried out on the effect of different media, carbon sources and illumination on omega-3 LC-PUFAs production by transgenic strain Pt_Elo5 and wild type P. tricornutum grown in 3.5 L bubble columns. The highest content of DHA (7.5% of total fatty acids, TFA) in transgenic strain was achieved in cultures grown in seawater salts, Instant Ocean (IO), supplemented with F/2 nutrients (F2N) under continuous light. After identifying the optimal conditions for omega-3 LC-PUFA accumulation in the small-scale experiments we compared EPA and DHA levels of the transgenic strain grown in a larger fence-style tubular photobioreactor and a raceway pond. We observed a significant production of DHA over EPA, generating an EPA/DPA/DHA profile of 8.7%/4.5%/12.3% of TFA in cells grown in a photobioreactor, equivalent to 6.4 μg/mg dry weight DHA in a mid-exponentially growing algal culture. Omega-3 LC-PUFAs production in a raceway pond at ambient temperature but supplemented with artificial illumination (110 μmol photons m^-2s^-1 ) on a 16:8h light:dark cycle, in natural seawater and F/2 nutrients was 24.8% EPA and 10.3% DHA. Transgenic strain grown in RP produced the highest levels of EPA (12.8%) incorporated in neutral lipids. However, the highest partitioning of DHA in neutral lipids was observed in cultures grown in PBR (7.1%). Our results clearly demonstrate the potential for the development of the transgenic Pt_Elo5 as a platform for the commercial production of EPA and DHA.     

Phosphate limitation as crucial factor to enhance yeast lipid production from short‐chain fatty acids

Microbial lipids for chemical synthesis are commonly obtained from sugar‐based substrates which in most cases is not economically viable. As a low‐cost carbon source, short‐chain fatty acids (SCFAs) that can be obtained from food wastes offer an interesting alternative for achieving an affordable lipid production process. In this study, SCFAs were employed to accumulate lipids using Yarrowia lipolytica ACA DC 50109. For this purpose, different amounts of SCFAs, sulfate, phosphate and carbon: phosphate ratios were used in both synthetic and real SCFAs‐rich media. Although sulfate limitation did not increase lipid accumulation, phosphate limitation was proved to be an optimal strategy for increasing lipid content and lipid yields in both synthetic and real media, reaching a lipid productivity up to 8.95 g/L h. Remarkably, the highest lipid yield (0.30 g/g) was achieved under phosphate absence condition (0 g/L). This fact demonstrated the suitability of using low‐phosphate concentrations to boost lipid production from SCFAs.

Microbial lipids for chemical synthesis are commonly obtained from sugar‐based substrates which in most cases is not economically viable. As a low‐cost carbon source, short‐chain fatty acids (SCFAs) that can be obtained from food‐wastes offer an interesting alternative for achieving an affordable lipid production process. In this study, SCFAs were employed to accumulate lipids using Yarrowia lipolytica ACA DC 50109.     

Effects of omega-3 and -6 fatty acids on Mycobacterium tuberculosis in macrophages and in mice

We recently showed that treatment of macrophages prior to Mycobacterium tuberculosis infection with the pro-inflammatory omega-6 lipid, arachidonic acid (AA) enhanced bacterial killing whereas the anti-inflammatory, omega-3 lipid eicosapentaenoic acid (EPA) stimulated bacterial growth. Here we tested if these effects were depending on when lipids were added to macrophages: before or during Mycobacterium smegmatis or M. tuberculosis infection. Collectively, our data suggested that a high omega-6 diet might be beneficial against mycobacteriosis, while a high omega-3 diet might be detrimental. AA also stimulated TNF-alpha secretion in M. tuberculosis-infected macrophages whereas EPA inhibited this process. AA strongly activated the MAP kinase p38 in uninfected cells but M. tuberculosis infected cells blocked the ability of AA to activate p38; AA-dependent killing is therefore independent of p38. We therefore tested diets enriched in omega-3 and omega-6 lipids on a mouse model of tuberculosis. In contrast to the in vitro results, the omega-6 tended to increase survival of M. tuberculosis in mice, while omega-3- tended to increase pathogen killing. Overall our results together with those previously reported in the literature suggest that it is almost impossible to predict, at the whole organism level, if a diet enriched in omega-3 or -6 will be beneficial or detrimental to intracellular pathogens.     

Identification of lipids in the cuticle of the parasitic nematode Anisakis simplex and the somatic tissues of the Atlantic cod Gadus morhua

The main aim of this work was to assign the cuticular lipids identified in a parasitic nematode and to distinguish those originating from its host. The hypothesis that long-chained fatty acids and sterols are imported by the parasite in the absence of certain enzymes was also tested. The organisms (Anisakis simplex and Gadus morhua) were extracted in petroleum ether and dichloromethane. Matrix-assisted laser desorption time-of-flight mass spectrometry (MALDI-TOF) was used to identify unknown components, and electrospray ionization mass spectrometry (ESI/MS) to verify recognized groups of lipids. The lipid classes identified in the surface layer were free saturated and unsaturated fatty acids, triacylglycerols, sterols and non-polar sphingolipids (ceramides, sphingoid bases). The most abundant fraction consisted of fatty acids. The predominant saturated acids were tetradecanoic acid in the petroleum ether extract of A. simplex, hexadecanoic acid in the dichloromethane extract of A. simplex, and also the polyunsaturated octadecahexaenoic and octadecatrienoic acids in both extracts of the parasitic nematode. The mass spectrum revealed the presence of fatty acids with different numbers of carbons, and with odd and even numbers of unsaturated bonds. The MALDI-TOF mass spectrum also identified triacylglycerols (TAGs). The dominant short-chain TAGs were CoCoCy:₁, CoCoPg and Bu0:0B:₆. The majority of TAGs were found in the ether and dichloromethane extracts of A. simplex. Sterols were the least common class of lipids found in the nematode extracts; most likely, this is the fraction that is entirely incorporated from the host organism because of the parasite’s inability to synthesize them. MALDI-TOF also identified non-polar sphingolipids - ceramides and sphingoid bases. The signals due to N-octanoyl-d-erythro-octasphinganine (m/z 288.3) and N-tetranoyl-d-erythro-tetradecasphinganine (m/z 316.4) were dominant on the mass spectra; quite a large number of short-chain non-polar sphingolipids were also identified.     

Hexadecenoic Fatty Acid Isomers in Human Blood Lipids and Their Relevance for the Interpretation of Lipidomic Profiles

Monounsaturated fatty acids (MUFA) are emerging health biomarkers, and in particular the ratio between palmitoleic acid (9cis-16:1) and palmitic acid (16:0) affords the delta-9 desaturase index that is increased in obesity. Recently, other positional and geometrical MUFA isomers belonging to the hexadecenoic family (C16 MUFA) were found in circulating lipids, such as sapienic acid (6cis-16:1), palmitelaidic acid (9trans-16:1) and 6trans-16:1. In this work we report: i) the identification of sapienic acid as component of human erythrocyte membrane phospholipids with significant increase in morbidly obese patients (n = 50) compared with age-matched lean controls (n = 50); and ii) the first comparison of erythrocyte membrane phospholipids (PL) and plasma cholesteryl esters (CE) in morbidly obese patients highlighting that some of their fatty acid levels have opposite trends: increases of both palmitic and sapienic acids with the decrease of linoleic acid (9cis,12cis-18:2, omega-6) in red blood cell (RBC) membrane PL were reversed in plasma CE, whereas the increase of palmitoleic acid was similar in both lipid species. Consequentially, desaturase enzymatic indexes gave different results, depending on the lipid class used for the fatty acid content. The fatty acid profile of morbidly obese subjects also showed significant increases of stearic acid (C18:0) and C20 omega-6, as well as decreases of oleic acid (9cis-18:1) and docosahexaenoic acid (C22:6 omega-3) as compared with lean healthy controls. Trans monounsaturated and polyunsaturated fatty acids were also measured and found significantly increased in both lipid classes of morbidly obese subjects. These results highlight the C16 MUFA isomers as emerging metabolic marker provided that the assignment of the double bond position and geometry is correctly performed, thus identifying the corresponding lipidomic pathway. Since RBC membrane PL and plasma CE have different fatty acid trends, caution must also be used in the choice of lipid species for the interpretation of lipidomic profiles.     

The effect of volatile fatty acids as a sole carbon source on lipid accumulation by Cryptococcus albidus for biodiesel production

The use of volatile fatty acids (VFAs) for microbial lipid accumulation was investigated in flask cultures of Cryptococcus albidus. The optimum culture temperature and pH were 25 °C and pH 6.0, respectively, and the highest lipid content (27.8%) was obtained with ammonia chloride as a nitrogen source. The lipid yield coefficient on VFAs was 0.167 g/g of C. albidus with a VFAs (acetic, propionic, butyric acids) ratio of 8:1:1, which was in good agreement with a theoretically predicted lipid yield coefficient of the VFAs as a carbon source. The major fatty acids of the lipids accumulated by C. albidus were similar to those of soybean oil and jatropha oil. A preliminary cost analysis shows that VFAs-based biodiesel production is competitive with current palm and soybean based biodiesels. Further process development for lower aeration cost and higher lipid yield will make this process more economical.     

Differential lipid and fatty acid profiles of photoautotrophic and heterotrophic Chlorella zofingiensis: Assessment of algal oils for biodiesel production

The objective of this study was to document and compare the lipid class and fatty acid composition of the green microalga Chlorella zofingiensis cultivated under photoautotrophic and heterotrophic conditions. Compared with photoautotrophic cells, a 900% increase in lipid yield was achieved in heterotrophic cells fed with 30 g L⁻¹ of glucose. Furthermore heterotrophic cells accumulated predominantly neutral lipids (NL) that accounted for 79.5% of total lipids with 88.7% being triacylglycerol (TAG); whereas photoautotrophic cells contained mainly the membrane lipids glycolipids (GL) and phospholipids (PL). Together with the much higher content of oleic acid (C18:1) (35.2% of total fatty acids), oils from heterotrophic C. zofingiensis appear to be more feasible for biodiesel production. Our study highlights the possibility of using heterotrophic algae for producing high quality biodiesel.     

The reproduction strategy of oyster ostrea edulis L. from the biochemical point of view

• 1.1. Influence of the biochemical composition of food (four species of micro-algae and one mixture) on the biochemical composition of gonads and larvae of O. edulis (total protein, lipid, carbohydrate, ash content, neutral and polar lipid class composition, amino acid composition and fatty acid composition of total, neutral and polar lipids) and the size of newly released larvae have been investigated.
• 2.2. Precentage of total lipids and triacylglycerols in gonads depends on that in algae (r = 0.52 and 0.69 accordingly).
• 3.3. Gonads rich in lipids had a higher level of triacylglycerols, phospholipids, polar lipids and a lower value of the ratio phosphatidylethanolamine/phosphatidylcholine (PE/PC) than gonads with a low lipid content.
• 4.4. Amino acid composition of gonads depends on that of food, in this case, essential acids are preferentially accumulated (Asp acid, Ser, Ala, Cys, Tyr and Pro) and two non-essential (Thr and Lys).
• 5.5. Fatty acid composition of total lipids of gonads was rather stable; except for the two essential acids 20:523 and 22:6w3, their percentage depends on that of food r = 0.65 and 0.65 accordingly). Fatty acid composition of neutral lipids was more diverse (in number and degree of variety) as compared to polar lipids.
• 6.6. Larvae released from oysters with gonads rich in lipids had a higher percentage of lipids, triacylglycerols, size and a lower ash percentage and value of ratio PE/PC, as compared to larvae from gonads with low lipid content. Total lipid and triacylglycerol contents in gonads correlate rather well with those in larvae (r = 0.77 and 0.47 accordingly).
• 7.7. Phospholipid class composition of larvae strongly depends on that of gonads. All the correlations are high and positive in character (except for phosphatidylinositol).
• 8.8. Amino acid composition of larvae depends on that of gonads and, as in the case with gonads, the same essential acids are accumulated in the first place.
• 9.9. Fatty acid composition of total lipids of newly released larvae was rather stable and independent on that of gonads except for total polyunsaturated acids (r = 0.70) and 20:5w3 (r = 0.65). Fatty acid composition of neutral lipids was lesser diverse (in number and degree of variation) as compared to polar lipids.

     

Synthesis of structured lipid with balanced omega-3: Omega-6 ratio by lipase-catalyzed acidolysis reaction: Optimization of reaction using response surface methodology

The present study deals with the production of structured lipid containing omega-3 and omega-6 fatty acids in the ratio of 1:1 by incorporating omega-3 fatty acids (α-linolenic acid) from linseed oil into groundnut oil using lipase (Lipozyme IM from Rhizomucor miehei) catalyzed acidolysis reaction in hexane. The reaction conditions were optimized by response surface methodology with a four-variable five-level central composite rotatable experimental design. The influence of four independent parameters, namely ratio of fatty acid concentrate from linseed to groundnut oil (0.66–1.98, w/w), reaction temperature (30–60 °C), enzyme concentration (1–5%) and reaction time (2–54 h) on omega-3 fatty acids incorporation into groundnut oil were optimized. Optimal conditions for the structured lipid containing omega-3 to omega-6 fatty acids in the ratio of 1:1 were determined to be; enzyme concentration 3.75% (w/w), temperature 37.5 °C, incubation time 30.81 h and ratio of free fatty acid concentrate from linseed oil to groundnut oil 1.16 (w/w).     

Production of eicosapentaenoic acid by the filamentous fungus Pythium irregulare

Because of the diversity of their lipids and fatty acid biosynthetic pathways, lower fungi may find utilization as sources of omega-3 or other polyunsaturated fatty acids (PUFA). Production of eicosapentaenoic acid (EPA) by the filamentous fungus, Pythium irregulare, has been demonstrated in 14-1 fermentors. Sweet whey permeate (lactose) was preferred over glucose as a substrate for production of a high-EPA-content lipid. Characterization of the lipid indicated that approximately 90% of the EPA was contained in the neutral lipid fraction. A specific productivity of 24.9 mg EPA/g dry biomass was achieved at 14°C, at which temperature the lipid contained 25.5% EPA and 54.2% PUFA. This is the highest mycelial EPA content for a fungal lipid that has been reported in the literature. Correspondence to: D. J. O'Brien     

Novel method to observe subtle structural modulation of stratum corneum on applying chemical agents

In the development of functional chemicals such as percutaneous penetration enhancers and cosmetics, the structural evidence at the molecular level in stratum corneum (SC) is highly desirable. We developed a method to observe a minute structural change of intercellular lipid matrix and corneocytes on applying the chemicals to the SC using synchrotron X-ray diffraction technique. The performance of the present method was demonstrated by applying typical chemicals, chloroform/methanol mixture, hydrophilic ethanol and hydrophobic d-limonene. From the small- and wide-angle X-ray diffraction we obtained the following results: on applying chloroform/methanol mixture the intercellular lipids were extracted markedly, on applying ethanol the intercellular lipid structure was slightly disrupted, ethanol molecules were taken into the corneocytes and in addition the pools of ethanol seem to be formed in the hydrophilic region of the intercellular lipid matrix in the SC, and on applying d-limonene the repeat distance of the long lamellar structure increased by incorporating d-limonene molecules, the intercellular lipid structure was slightly disrupted, and the pools of d-limonene were formed in the hydrophobic region of the intercellular lipid matrix in the SC.     

Lipid composition of the entomopathogenic fungus Nomuraea rileyi

The total lipid content, neutral and polar lipid composition, and fatty acid profiles were determined for the different developmental stages of the entomopathogenic fungus, Nomuraea rileyi. In general, the lipid composition of N. rileyi was found to be very similar to that of other Fungi Imperfecti. Triacylglycerides and sterols were the major neutral lipids and phosphatidylethanolamine, phosphatidylinositol, and phosphatidylserine were the major polar lipids. Phosphatidylcholine, resolved in conidial and mycelial samples, was not detected in hyphal body samples. The major fatty acids were palmitic, oleic, and linoleic. Stearic acid was detected as a minor component of hyphal body samples. During conidiogenesis the overall lipid composition was altered in (1) a reduction in total lipid content, (2) an increase in the polar/neutral lipid ratio, and (3) an increase in the degree of fatty acid unsaturation.     

Polysaccharide and lipid composition of the brown seaweed <Emphasis Type="Italic">Laminaria gurjanovae</Emphasis>

Polysaccharide and lipid composition of the Pacific brown seaweed Laminaria gurjanovae is determined. Alginic acid is shown to be the main polysaccharide of its biomass (about 28%); it consists of mannuronic and guluronic acid residues at a ratio of 3: 1. The yield of water-soluble polymannuronic acid is low and does not exceed 1.1% of dry biomass. High laminaran content (about 22%) is found, whereas the yield of fucoidan is no more than 3.6%. Laminaran consists of two fractions, soluble and insoluble in cold water, their ratio is 2.5: 1. Insoluble laminaran is a practically linear 1,3-β-D-glucan, and the soluble fraction was shown to be 1,3;1,6-β-D-glucan. The oligosaccharide products of desulfation or partial acidic hydrolysis of fucoidan were studied by MALDI TOF MS; they were found to be fuco- and galactooligosaccharides. The fucoidan is suggested to be a highly sulfated partially acetylated galactofucan (Fuc/Gal is ～1: 1). The main lipid components of the dried L. gurjanovae are neutral lipids and glyceroglycolipids, whereas phospholipids are found in minor amounts. The main fatty acid components of lipids are 14:0, 16:0, 16:1 ω-7, 18:1 ω-7 and 18:2 ω-6 acids.