Lipids of the Green Alga BotryococcusCultured in a Batch Mode

The lipid fraction of the green alga Botryococcuscultured in a batch mode was found to contain polar lipids (more than 50% of the total lipids), di- and triacylglycerols, sterols and their esters, free fatty acids, and hydrocarbons. In aging culture, the content of polar lipids somewhat decreased and that of triacylglycerols increased by more than four times. The content of hydrocarbons in the algal biomass did not exceed 0.9% and depended little on the culture age. Intracellular lipids contained saturated and unsaturated (mono-, di-, and trienoic) fatty acids. The maximum content of C_{16 : 3}and -C_{18 : 3}fatty acids (up to 35% of the total fatty acids) was detected in the phase of active growth. The extracellular and intracellular lipids of the alga differed in the proportion of particular lipids and in the fatty acid pattern.     

Chemical analysis of osmium tetroxide staining in adipose tissue using imaging ToF-SIMS

Osmium tetroxide (OsO₄) is a commonly used stain for unsaturated lipids in electron and optical microscopy of cells and tissues. In this work, the localization of osmium oxide and specific lipids was independently monitored in mouse adipose tissue by using time-of-flight secondary ion mass spectrometry with Bi cluster primary ions. Substance-specific ion images recorded after OsO₄ staining showed that unsaturated C18 fatty acids were colocalized with osmium oxide, corroborating the view that osmium tetroxide binds to unsaturated lipids. In contrast, saturated fatty acids (C14, C16 and C18) and also unsaturated C16 fatty acids show largely complementary localizations to osmium oxide. Furthermore, the distributions of saturated and unsaturated diglycerides are consistent with the specific binding of osmium oxide to unsaturated C18 fatty acids. The abundance of ions, characteristic of phospholipids and proteins, is strongly decreased as a result of the osmium staining, suggesting that a large fraction of these compounds are removed from the tissue during this step, while ions related to fatty acids, di- and triglycerides remain strong after osmium staining. Ethanol dehydration after osmium staining results in more homogeneous distributions of osmium oxide and unsaturated lipids. This work provides detailed insight into the specific binding of osmium oxide to different lipids.     

Peroxisomal lipid degradation via β-and α-oxidation in Mammals

Peroxisomal β-oxidation is involved in the degradation of long chain and very long chain fatty acyl-(coenzyme A)CoAs, long chain dicarboxylyl-CoAs, the CoA esters of eicosanoids, 2-methyl-branched fatty acyl-CoAs (e.g. pristanoyl-CoA), and the CoA esters of the bile acid intermediates di- and trihydroxycoprostanic acids (side chain of cholesterol). In the rat, straight chain acyl-CoAs (including the CoA esters of dicarboxylic fatty acids and eicosanoids) are β-oxidized via palmitoyl-CoA oxidase, multifunctional protein-1 (which displays 2-enoyl-CoA hydratase and L-3-hydroxyacyl-CoA, dehydrogenase activities) and peroxisomal thiolase. 2-Methyl-branched acyl-CoAs are degraded via pristanoyl-CoA oxidase, multifunctional protein-2 (MFP-2) (which displays 2-enoyl-CoA hydratase and D-3-hydroxyacyl-CoA dehydrogenase activities) and sterol carrier protein-X (SCPX; displaying 2-methyl-3-oxoacyl-CoA thiolase activity). The side chain of the bile acid intermediates is shortened via one cycle of β-oxidation catalyzed by trihydroxycoprostanoyl-CoA oxidase, MFP-2 and SCPX. In the human, straight chain acyl-CoAs are oxidized via palmitoyl-CoA oxidase, multifunctional protein-1, and peroxisomal thiolase, as is the case in the rat. The CoA esters of 2-methyl-branched acyl-CoAs and the bile acid intermediates, which also possess a 2-methyl substitution in their side chain, are shortened, via branched chain acyl-CoA oxidase (which is the human homolog of trihydroxycoprostanoyl-CoA oxidase), multifunctional protein-2, and SCPX. The rat and the human enzymes have been purified, cloned, and kinetically and stereochemically characterized. 3-Methyl-branched fatty acids such as phytanic acid are not directly β-oxidizable because of the position of the methyl-branch. They are first shortened by one carbon atom through the a-oxidation process to a 2-methyl-branched fatty acid (pristanic acid in the case of phytanic acid), which is then degraded via peroxisomal β-oxidation. In the human and the rat, α-oxidation is catalyzed by an acyl-CoA synthetase (producing a 3-methylacyl-CoA), a 3-methylacyl-CoA 2-hydroxylase (resulting in a 2-hydroxy-3-methylacyl-CoA), and a 2-hydroxy-3-methylacyl-CoA lyase that cleaves the 2-hydroxy-3-methylacyl-CoA into a 2-methyl-branched fatty aldehyde and formyl-CoA. The fatty aldehyde is dehydrogenated by an aldehyde dehydrogenase to a 2-methyl-branched fatty acid while formyl-CoA is hydrolyzed to formate, which is then converted to CO₂. The activation, hydroxylation and cleavage reactions and the hydrolysis of formyl-CoA are performed by peroxisomal enzymes; the aldehyde dehydrogenation remains to be localized whereas the conversion of formate to CO₂ occurs mainly in the cytosol.     

Distribution of radioactivity in myelin lipids following subcutaneous injection of [14C]stearate

Blood fatty acids are an important parameter for the synthesis of brain myelin as exogenous stearic acid is needed: after subcutaneous injection to 18-day-old mice this labelled stearic acid is transported into brain myelin and incorporated into its lipids. However the acid is partly metabolized in the brain by elongation (thus providing very long chain fatty acids, mainly lignoceric acid) or by degradation to acetate units (utilized for synthesis of medium chain fatty acids as palmitic acid, and cholesterol). These metabolites are further incorporated into myelin lipids. The myelin lipid radioactivity increases up to 3 days; most of the activity is found in phospholipids; their fatty acids are labelled in saturated as well as in polyunsaturated homologues but sphingolipids, especially cerebrosides, contain also large amounts of radioactivity (which is mainly found in very long chain fatty acids, almost all in lignoceric acid). The occurrence of unesterified fatty acids must be pointed out, these molecules unlike other lipids, are found in constant amount (expressed in radioactivity per mg myelin lipid).     

Metabolism of tween-Fatty Acid esters by cultured soybean cells : kinetics of incorporation into lipids, subsequent turnover, and associated changes in endogenous Fatty Acid synthesis

Uptake of Tween-fatty acid esters and incorporation of the fatty acids into lipids by soybean (Glycine max [L.] Merr.) suspension cultures was investigated, together with subsequent turnover of the incorporated fatty acids and associated changes in endogenous fatty acid synthesis. Tween uptake was saturable, and fatty acids were rapidly transferred from Tweens to all acylated lipids. Patterns of incorporation into glycerolipids were similar in cells treated with Tweens carrying [1-¹⁴C]-fatty acids and in cells treated with [1-¹⁴C]acetate, indicating that exogenous fatty acids were used for glycerolipid synthesis essentially as if they had been made by the cell. In Tween-treated cells neutral lipids (which include Tweens) initially accounted for the majority of lipid radioactivity. Radioactivity was then rapidly transferred to glycerolipids. A transient pool of free fatty acids accounting for up to 10% of lipid radioactivity was observed. This was consistent with the hypothesis that fatty acids are transferred from Tweens to lipids by deacylation of the Tweens, creating a pool of free fatty acids which are then used for lipid synthesis. Sterols were only slightly labeled in cells treated with Tweens, but accounted for nearly 50% of lipid radioactivity in cells treated with acetate. This suggested very little degradation and reutilization of the radioactive fatty acids in cells treated with Tweens. In cells treated with either [1-¹⁴C]acetate or Tween-[1-¹⁴C]-18:1, 70% of the initial fatty acid radioactivity remained in fatty acids after a 100 hour chase. By contrast, fatty acids not normally present disappeared more rapidly, suggesting differential treatment of such fatty acids compared with those normally present. Cells which had incorporated large amounts of exogenous fatty acids altered fatty acid synthesis in three distinct ways: (a) amounts of [1-¹⁴C]acetate incorporated into fatty acids were reduced; (b) cells incorporating exogenous unsaturated fatty acids increased the proportion of [1-¹⁴C]acetate partitioned into saturated fatty acids, while the converse was true of cells which had incorporated exogenous saturated fatty acids; (c) desaturation of 18:1 to 18:2 and 18:3 was reduced in cells which had incorporated unsaturated fatty acids. These results suggest that Tween-fatty acid esters will be useful for supplying fatty acids to cells for a variety of studies related to fatty acid or membrane metabolism.     

FATTY ACIDS AND HYDROXY FATTY ACIDS IN THREE SPECIES OF FRESHWATER EUSTIGMATOPHYTES

The monocarboxylic fatty acids and hydroxy fatty acids of three species of freshwater microalgae—Vischeria punctata Vischer, Vischeria helvetica (Vischer et Pascher) Taylor, and Eustigmatos vischeri (Hulbert) Taylor, all from the class Eustigmatophyceae— were examined. Each species displayed a very similar distribution of fatty acids, the most abundant of which were 20:5n-3, 16:0, and 16:1n-7; C₁₈ polyunsaturated fatty acids were minor components. These fatty acid distributions closely resemble those found in marine eustigmatophytes but are quite distinct from those found in most other algal classes. These microalgae also contain long-chain saturated and unsaturated monohydroxy fatty acids. Two distinct types of hydroxy fatty acids were found: a series of saturated α-hydroxy acids ranging from C₂₄ to C₃₀ with a shorter series of monounsaturated α-hydroxy acids ranging from C₂₆ to C₃₀ together with a series of saturated β-hydroxy acids ranging from C₂₆ to C₃₀. The latter have not previously been reported in either marine or freshwater microalgae, although C₃₀ to C₃₄ midchain (ω-18)-hydroxy fatty acids have been identified in hydrolyzed extracts from marine eustigmatophytes of the genus Nannochloropsis, and C₂₂ to C₂₆ saturated and monounsaturated α-hydroxy fatty acids have been found in three marine chlorophytes. These findings have provided a more complete picture of the lipid distributions within this little studied group of microalgae as well as a range of unusual compounds that might prove useful chemotaxonomic markers. The functions of the hydroxy fatty acids are not known, but a link to the formation of the lipid precursors of highly aliphatic biopolymers is suggested.     

Comparison of fatty acid patterns in plant parts and respective callus cultures of Cucumis melo

Root, hypocotyl, cotyledon, stem and leaf of Cucumis melo var. utilissimus seedlings were used for callus induction. Comparison was made between these parts, between callus tissues originating from all the parts and between each part and its callus, with respect to the fatty acid composition of total lipids. In all the parts there was a greater proportion of unsaturated fatty acids, the predominant fatty acid in root, stem and leaf being linolenic acid whilst in the cotyledon linoleic predominated. In the hypocotyl these two acids were present in equal amounts. In callus cultures the proportion of saturated acids was greater and the predominant fatty acid was palmitic. The major unsaturated fatty acid in callus cultures was linolenic. The analysis showed that callus tissue and its respective plant part had different fatty acid patterns and that all the callus cultures had very similar patterns irrespective of their origin.     

Adaptational changes in cellular phospholipids and fatty acid composition of the food pathogen Listeria monocytogenes as a stress response to disinfectant sanitizer benzalkonium chloride

Aims: This study provides a first approach to observing the alterations of the cell membrane lipids in the adaptation response of Listeria monocytogenes to the sanitizer benzalkonium chloride. Methods and Results: A thorough investigation of the composition of polar and neutral lipids from L. monocytogenes grown when exposed to benzalkonium chloride is compared to cells optimally grown. The adaptation mechanism of L. monocytogenes in the presence of benzalkonium chloride caused (i) an increase in saturated‐chain fatty acids (mainly C_16:0 and C_18:0) and unsaturated fatty acids (mainly C_16:1 and C_18:1) at the expense of branched‐chain fatty acids (mainly C_a‐15:0 and C_a‐17:0) mainly because of neutral fatty acids; (ii) no alteration in the percentage of neutral and polar lipid content among total lipids; (iii) a decrease in lipid phosphorus and (iv) an obvious increase in the anionic phospholipids and a decrease in the amphiphilic phosphoaminolipid. Conclusions: These lipid changes could lead to decreased membrane fluidity and also to modifications of physicochemical properties of cell surface and thus changes in bacterial adhesion to abiotic surfaces. Significance and Impact of the Study: The adaptation and resistance of L. monocytogenes to disinfectants is able to change its physiology to allow growth in food‐processing plants. Understanding microbial stress response mechanisms would improve the effective use of disinfectants.     

Microsomal fatty acyl-CoA transacylation and hydrolysis: fatty acyl-CoA species dependent modulation by liver fatty acyl-CoA binding proteins1

Liver and intestinal cytosol contain abundant levels of long chain fatty acyl-CoA binding proteins such as liver fatty acid binding protein (L-FABP) and acyl-CoA binding protein (ACBP). However, the relative function and specificity of these proteins in microsomal utilization of long chain fatty acyl-CoAs (LCFA-CoAs) for sequential transacylation of glycerol-3-phosphate to form phosphatidic acid is not known. The results showed for the first time that L-FABP and ACBP both stimulated microsomal incorporation of the monounsaturated oleoyl-CoA and polyunsaturated arachidonoyl-CoA 8–10-fold and 2–3-fold, respectively. In contrast, these proteins inhibited microsomal utilization of the saturated palmitoyl-CoA by 69% and 62%, respectively. These similar effects of L-FABP and ACBP on microsomal phosphatidic acid biosynthesis were mediated primarily through the activity of glycerol-3-phosphate acyltransferase (GPAT), the rate limiting step, rather than by protecting the long chain acyl-CoAs from microsomal hydrolase activity. In fact, ACBP but not L-FABP protected long chain fatty acyl-CoAs from microsomal acyl-CoA hydrolase activity in the order: palmitoyl-CoA>oleoyl-CoA>arachidonoyl-CoA. In summary, the data established for the first time a role for both L-FABP and ACBP in microsomal phosphatidic acid biosynthesis. By preferentially stimulating microsomal transacylation of unsaturated long chain fatty acyl-CoAs while concomitantly exerting their differential protection from microsomal acyl-CoA hydrolase, L-FABP and ACBP can uniquely function in modulating the pattern of fatty acids esterified to phosphatidic acid, the de novo precursor of phospholipids and triacylglycerols. This may explain in part the simultaneous presence of these proteins in cell types involved in fatty acid absorption and lipoprotein secretion.     

The Arabidopsis cer26 mutant,like the cer2 mutant,is specifically affected in the very long chain fatty acid elongation process

Plant aerial organs are covered by cuticular waxes, which form a hydrophobic crystal layer that mainly serves as a waterproof barrier. Cuticular wax is a complex mixture of very long chain lipids deriving from fatty acids, predominantly of chain lengths from 26 to 34 carbons, which result from acyl‐CoA elongase activity. The biochemical mechanism of elongation is well characterized; however, little is known about the specific proteins involved in the elongation of compounds with more than 26 carbons available as precursors of wax synthesis. In this context, we characterized the three Arabidopsis genes of the CER2‐like family: CER2, CER26 and CER26‐like . Expression pattern analysis showed that the three genes are differentially expressed in an organ‐ and tissue‐specific manner. Using individual T–DNA insertion mutants, together with a cer2 cer26 double mutant, we characterized the specific impact of the inactivation of the different genes on cuticular waxes. In particular, whereas the cer2 mutation impaired the production of wax components longer than 28 carbons, the cer26 mutant was found to be affected in the production of wax components longer than 30 carbons. The analysis of the acyl‐CoA pool in the respective transgenic lines confirmed that inactivation of both genes specifically affects the fatty acid elongation process beyond 26 carbons. Furthermore, ectopic expression of CER26 in transgenic plants demonstrates that CER26 facilitates the elongation of the very long chain fatty acids of 30 carbons or more, with high tissular and substrate specificity.     

Protein deficiency and age related alterations in rat peritoneal macrophage lipids

The effects of dietary protein restriction and age on the thioglycollate elicited peritoneal macrophage lipid constituents were studied. Impact of subtle changes in lipid components on macrophage functions have been assessed. Lipid profiles of macrophages recovered from rats fed 20 and 4% protein diets and stock diet fed rats (0 and 3 wk) were comparable qualitatively. Quantitative analysis however revealed significant decrease in phospholipids (30–40%) and consequent elevation of cholesterol/phospholipid molar ratios in the protein depleted and young rats (0 wk), compared to the protein fed groups. The protein deficient and the young rats also exhibited accumulation of certain neutral lipids and reduction in triglycerides. Analysis of fatty acid methyl esters of macrophage phospholipids revealed the predominance of long chain polyunsaturated fatty acids even when oleic (C_18:1) and linoleic (C_18:2) formed the bulk of unsaturated fatty acids in the diet. However, the long chain poly unsaturated fatty acid content, particularly the docosahexaenoic acid (C_22:6n-3) was greatly reduced in the protein depleted and 0 wk rats. Observed changes in the long chain polyunsaturated fatty acids of macrophage phospholipids may be of physiological significance as they modulate the immunological functions of the cell.     

Ultrastructure and lipid chemistry of specialized epidermal structure of Indian porcupines and hedgehog

Poddar‐Sarkar, M., Raha, P., Bhar, R., Chakraborty, A. and Brahmachary, R.L. 2011. Ultrastructure and lipid chemistry of specialized epidermal structure of Indian porcupines and hedgehog. —Acta Zoologica (Stockholm) 92 : 134–140. In the present study, we investigated the ultrastructural variations of specialized epidermal structure of Indian porcupines (Hystrix indica and Atherurus macrourus) and hedgehog (Hemiechinus collaris) as well as the variation in the fatty acid composition of total lipid fraction. Scanning electron microscope images reveal the usual scaly structure in surface view and network of channels in cross‐section but with different orientation of partition walls. The lipid profile reveals the presence of free sterol, long‐chain alcohol, free fatty acids, wax ester and sterol ester in all the three cases and trace amount of triglyceride, diglyceride and monoglyceride. Gas chromatography–mass spectrometry analysis of fatty acid methyl ester of total lipid fraction indicates the presence of C₈‐C₂₂ fatty acids in Hystrix indica, C₈‐C₁₈ in Atherurus macrourus and C₈‐C₂₀ fatty acids in Hemiechinus collaris. It is interesting to note that the total lipid fraction of hedgehog shows no branched‐chain, unsaturated and odd‐carbon fatty acids. Odd‐carbon fatty acid and branched‐chain fatty acids detected in the adult H. indica but were absent in juvenile H. indica as well as in A. macrourus. With the exception of C_18:1, the other unsaturated fatty acids were also absent in both juvenile H. indica and A. macrourus.     

FATTY ACID ABNORMALITY IN ADRENOLEUKODYSTROPHY

—Recent clinical and morphological evidence established that adrenoleukodystrophy is a distinct X-linked genetic disorder. Fatty acid compositions of lipids in the brain, adrenal and serum from seven patients were examined. Cholesterol esters of both brain and adrenal contained substantial proportions of fatty acids longer than C₂₂ (11.8–41.9% of total in the brain and 13.4-34.8% of total in the adrenal), while cholesterol esters from normal and pathological control specimens contained very little. These very long chain fatty acids were generally saturated in brain cholesterol esters but significant amounts of unsaturated long chain fatty acids were also present in adrenal cholesterol esters. The long chain fatty acids showed bell-shaped distribution with C₂₅ or C₂₆ at the peak. Ganglio-sides from patients’white matter also showed increased proportions of very long-chain fatty acids, up to 50% of the total. Qualitatively similar but much milder fatty acid abnormalities were also found in galactosylceramide of the brain. On the other hand, fatty acids and fatty aldehydes of brain glycerophospholipids, adrenal free fatty acids, triglycerides and glycerophospholipids were not abnormal. Furthermore, serum cholesterol esters from two patients did not show the long-chain fatty acid abnormality found in brain and adrenal cholesterol esters. Sequential extractions with acetone and hexane established that the characteristic birefringent material in the brain and adrenal is indeed cholesterol esters with very long chain fatty acids. This type of fatty acid abnormality has not been described in other pathological conditions and may well represent the unique biochemical abnormality that is directly related to the fundamental genetic defect underlying adrenoleukodystrophy.     

Cutins of Malus pumila fruits and leaves

The cutins of fruits and leaves of four apple cultivars have been analysed using TLC, GLC and GC-MS. They are similarly composed of saturated, monounsaturated and diunsaturated fatty, hydroxy-fatty and epoxyhydroxy-fatty acids. The most abundant monomers are 18-hydroxyoctadeca-9,12-dienoic, 10,16-dihydroxyhexadecanoic, 9,10-epoxy-18-hydroxyoctadec-12-enoic, 9,10-epoxy-18-hydroxyoctadecanoic and 9,10,18-trihydroxyoctadecanoic acids. The fruit cutins have high contents of epoxides (35–40%) and unsaturated components ( > 40%) and C₁₈ compounds predominate over C₁₆. The leaf cutins contain smaller amounts of unsaturated components than the fruits and higher proportions of C₁₆ compounds. The adaxial leaf cutin differs in composition from the abaxial. 10,16-Dihydroxyhexadecanoic and 9,10-epoxy-18-hydroxoctadecanoic acids are the major constituents (each ca. 30%) of the adaxial leaf cutin and 10,16-dihydroxyhexadecanoic acid (55–65%) predominates in the abaxial.     

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’.     

Subject index

Heats of fusion and heat capacities have been measured for saturated, unsaturated and hydroxy fatty acids, differing in degree of unsaturation, geometric isomerism, and position of unsaturated and hydroxy groups. Entropies of fusion are used to draw conclusions concerning molecular structure of fatty acid chains and lateral chain-chain interactions. Position of the functional group on the chain does not seem to significantly affect the entropy values for trans and cis single double bonds and single triple bonds, but differences are noted with hydroxy group position. Whereas single acid triglycerides of saturated acids have entropies which are about three times that of the corresponding acid, cis and trans single acid triglycerides do not show the same relationship with their corresponding acids. Comparing entropies of fusion for certain groups of fatty acids, only differing in carbon number, allows the estimation of chain equivalence with saturated fatty acids. Hence, for example it is shown that a 22 to 23-carbon cis mono-unsaturated fatty acid is equivalent to an 18-carbon saturated fatty acid.     

Brain,liver, and adipose tissue erucic and very long chain fatty acid levels in adrenoleukodystrophy patients treated with glyceryl trierucate and trioleate oils (Lorenzo's Oil)

Brain, liver, and adipose lipids were studied in the postmortem tissues of four adrenoleukodystrophy patients who had been treated with a mixture of glyceryl trioleate and trierucate olis (Lorenzo's Oil) and compared to 7 untreated ALD patients and 3 controls. The dietary therapy appeared to reduce the levels of saturated very long chain fatty acids in the plasma, adipose tissue and liver; in the brain they were reduced in only one of the four patients. While substantial amounts of erucic acid were present in some of the tissues even 12 months after therapy had been discontinued, the levels in brain did not exceed those in controls at any time. The failure of erucic acid to enter the brain in significant quantity may be a factor in the disappointing results of dietary therapy for adrenoleukodystrophy.Special issue dedicated to Dr. Marjorie B. Lees.     

Fatty acid composition of mitochondrial membranes of pea germs exposed to insufficient watering and treated with organophosphorous plant growth regulator

The influence of insufficient watering and a melamine salt of bis(oxymethyl)-phosphonic acid (melaphen) on fatty acid composition of mitochondrial membrane of pea seedlings has been studied. It is shown that insufficient watering results in a 1.57-fold decrease in the ratio of unsaturated to saturated C₁₈ fatty acids and in a 3.04-fold decrease in the ratio of unsaturated to saturated C₂₀ fatty acids. The modification of fatty acid composition of mitochondrial membranes was associated with the alterations in their functional state: maximal rates of oxidation of NAD-dependent substrates and the rates of electron transport at the end of respiratory chain decreased. A preliminary treatment of the seeds with 3 × 10⁻⁹ M melaphen restored the maximal rates of oxidation of NAD-dependent substrates to the control values. We suggest that the alterations of the electron transport rates in respiratory chain in mitochondria are related to the physicochemical state of the membranes of these organelles, as the treatment with melaphen prevented the changes in fatty acid composition of the membranes of seedlings growing under the conditions of insufficient watering.     

Lipid and hydrocarbon compositions of a collection strain and a wild sample of the green microalga Botryococcus

Lipid composition and hydrocarbon structure of two colonial green algae of the genus Botryococcus, i.e., a museum strain and a field sample collected for the first time from Lake Shira (Khakasia, Siberia), have been compared. Polar lipids, diacylglycerols, alcohols, triacylglycerols, sterols, sterol esters, free fatty acids and hydrocarbons have been identified among lipids in the laboratory culture. The dominant fraction in the museum strain was formed by polar lipids (up to 50% of the lipids) made up of fatty acids from C₁₂ to C₂₄. Palmitic, oleic, C₁₆ - C₁₈ dienoic and trienoic acids were the main fatty acids of the museum strain. Aliphatic hydrocarbons were found in the lipid of the museum strain. However, these amounted maximally to about 1% of the dry biomass at the end of exponential growth phase. The qualitative and quantitative compositions of FAs and hydrocarbons of the museum strain of Botryococcus, (registered at the Cambridge collection as Botryococcus braunii Kutz No LB 807/1 Droop 1950 H-252) differed from those of the Botryococcus strain described in the literature as Botryococcus braunii. The Botryococcus sp. found in Lake Shira is characterized by a higher lipid content (<40% of the dry weight). Polar lipids, sterols, triacylglycerols, free fatty acids and hydrocarbons have been identified among lipids in the field sample. The main lipids in this sample were dienes and trienes (hydrocarbons <60% of total lipid). Monounsaturated and very long chain monounsaturated fatty acids, including C_28:1 and C_32:1 acids, were identified in the Botryococcus found in Lake Shira. The chemo-taxonomic criteria allow us to unequivocally characterize the organism collected from Lake Shira as Botryococcus braunii, race A.