LIPID COMPOSITION OF CHLORARACHNIOPHYTES (CHLORARACHNIOPHYCEAE) FROM THE GENERA BIGELOWIELLA,GYMNOCHLORA, AND LOTHARELLA1

The Chlorarachniophyceae are unicellular eukaryotic algae characterized by an amoeboid morphology that may be the result of secondary endosymbiosis of a green alga by a nonphotosynthetic amoeba or amoeboflagellate. Whereas much is known about the phylogeny of chlorarachniophytes, little is known about their physiology, particularly that of their lipids. In an initial effort to characterize the lipids of this algal class, four organisms from three genera were examined for their fatty acid and sterol composition. Fatty acids from lipid fractions containing chloroplast‐associated glycolipids, storage triglycerides, and cytoplasmic membrane‐associated polar lipids were characterized. Glycolipid‐associated fatty acids were of limited composition, principally eicosapentaenoic acid [20:5(n‐3)] and hexadecanoic acid (16:0). Triglyceride‐associated fatty acids, although minor, were found to be similar in composition. The polar lipid fraction was dominated by lipids that did not contain phosphorus and had a more variable fatty acid composition with 16:0 and docosapentaenoic acid [22:5(n‐3)] dominant along with a number of minor C₁₈ and C₂₀ fatty acids. Crinosterol and one of the epimeric pair poriferasterol/stigmasterol were the sole sterols. Several genes required for synthesis of these sterols were computationally identified in Bigelowiella natans Moestrup. One sterol biosynthesis gene showed the greatest similarity to SMT1 of the green alga, Chlamydomonas reinhardtii. However, homologues to other species, mostly green plant species, were also found. Further, the method used for identification suggested that the sequences were transferred to a genetic compartment other than the likely original location, the nucleomorph nucleus.     

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.     

Lipidomics of the sea sponge Amphimedon queenslandica and implication for biomarker geochemistry

Demosponges are a rich natural source of unusual lipids, some of which are of interest as geochemical biomarkers. Although demosponges are animals, they often host dense communities of microbial symbionts, and it is therefore unclear which lipids can be synthesized by the animal de novo, and which require input from the microbial community. To address this uncertainty, we analyzed the lipids of Amphimdeon queenslandica, the only demosponge with a published genome. We correlated the genetic and lipid repertoires of A. queenslandica to identify which biomarkers could potentially be synthesized and/or modified by the sponge. The fatty acid profile of A. queenslandica is dominated by an unusual Δ^5,9 fatty acid (cis‐5,9‐hexacosadienoic acid)—similar to what has been found in other members of the Amphimdeon genus—while the sterol profile is dominated by C₂₇‐C₂₉ derivatives of cholesterol. Based on our analysis of the A. queenslandica genome, we predict that this sponge can synthesize sterols de novo, but it lacks critical genes necessary to synthesize basic saturated and unsaturated fatty acids. However, it does appear to have the genes necessary to modify simpler products into a more complex “algal‐like” assemblage of unsaturated fatty acids. Ultimately, our results provide additional support for the poriferan affinity of 24‐isopropylcholestanes in Neoproterozoic‐age rocks (the “sponge biomarker” hypothesis) and suggest that some algal proxies in the geochemical record could also have animal contributions.     

Cholesteryl esters of the glioblastoma

Abstract The sterol ester fraction in the human glioblastoma was isolated and characterized. Cholesterol was identified as the constituent sterol. Contained in the complex mixture of fatty acids were members with 0-4 double bonds and 14-28 carbon atoms. About 1/4 of the acids were polyunsaturated. Long chain members (C₂₀ and above) composed 1/3 of the mixture. The results suggest that the sterol ester component in the glioblastoma does not derive from blood plasma.     

Enhancement of fruity aroma production of Pseudomonas fragi grown on skim milk,whey and whey permeate supplemented with C3-C7 fatty acids

Summary Pseudomonas fragi strain CRDA 037 produced a fruity aroma when grown in skim milk-, whey-and whey permeate-based culture media. The production of the odour-active metabolites was related to the lipid content of these media but was not influenced by the pH of the cultures. Analysis of the fruity aroma revealed that esters of fatty acids were some of the odouractive metabolites. Addition of C₃-C₇ fatty acids to the culture at 0 h stimulated the production of the corresponding fatty acid esters from 12 to 1570 times compared to unsupplemented media. Supplementation of the culture media with the C₃-C₇ fatty acids at 48 h, resulted in a 1.4- to 932-fold increase in the ethyl ester concentration.     

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.     

Atherurus karnuliensis Lydekker, 1886, a Pleistocene brush-tailed porcupine from India, China and Vietnam

Pleistocene porcupine remains from China allocated toAtherurus sp.,Atherurus cf.macrourus andTrichys cf.fasciculata, and from Vietnam toAtherurus macrourus have been studied. These fossils have been compared with the type material of the PleistoceneA. karnuliensis Lydekker, 1886 from India and with the extant speciesA. macrourus (Linnaeus, 1758) andTrichys fasciculata (Shaw, 1801). As a result, all fossil specimens studied are allocated toA. karnuliensis.     

Influences of porcupine (Hystrix indica) activity on the slopes on the northern Negev mountains — Germination and vegetation renewal in different geomorphological types and slope directions

Summary Preliminary results show that the number and survival of seedlings within the diggings of the Indian crested porcupine (Hystrix indica) is usually higher than in the surrounding area. Species like Erodium hirtum (Willd.) (hemicryptophyte), Helianthemum vesicarium Boiss. (perennial), and Diplotaxis harra (Forssk.) Boiss. are conspicuous by their appearance in the diggings of the porcupine more than between the diggings. In contrast there are plants like Helianthemum ledifolium (L.) Mill. (annual), that appear in high numbers outside the diggings. In the case of Erodium hirtum, it appears that the porcupines help in rejuvenating the population. The porcupines feed on the older underground plant bulbs and the pockets formed by their diggings are convenient habitats for germination and growth of the young seedlings.     

Metabolic rates,food consumption and thermoregulation in seasonal acclimatization of the Cape porcupine Hystrix africaeaustralis

Summary Metabolic rates by means of oxygen consumption (VO₂) at various ambient temperatures (T _a) and food consumption as well as water intake and thermoregulation were compared between individuals of the Cape porcupine Hystrix africaeaustralis acclimated to T _a=32°C with a photoperiod of 16L:8D summer-acclimated and T _a=10°C; 8L:16D winter-acclimated. The lower critical temperature as well as overall minimal thermal conductance were lower for the winter-acclimated porcupines when compared to summer-acclimated ones, while VO₂ at the thermoneutral-zone was significantly (P<0.001) higher in the winter-acclimated porcupines. Dry matter intake, apparent digestible dry matter intake, gross digestible energy intake, as well as water intake, were significantly higher in the winter-acclimated porcupines. Yet, while dry matter intake increased 4 times in the winter-acclimated porcupines, apparent digestible dry matter increased only at a rate of 2.9 times. This difference is better reflected in terms of digestibility efficiency which in the winter-acclimated porcupines is only at a rate of 67.5% while in the summer-acclimated porcupines it is at a rate of 90%. From the results of this study, it is possible to assume that heat production in the winter-acclimated porcupines is partly increased by food intake. Increased heat production on the one hand, and a decrease in overall minimal thermal conductance on the other, seem to be important mechanisms in winter acclimatization of the Cape porcupine.     

Squishy lipids: Temperature effects on the betaine and galactolipid profiles of a C18/C18 peridinin‐containing dinoflagellate,Symbiodinium microadriaticum (Dinophyceae), isolated from the mangrove jellyfish,Cassiopea xamachana

Previous work from our laboratory has shown dinoflagellates, which possess the carotenoid peridinin, have been divided into two clusters based on plastid galactolipid fatty acid composition. In one cluster major forms of monogalactosyldiacylglycerol (MGDG) and digalactosyldiacylglycerol (DGDG), lipids that comprise the majority of photosynthetic membranes, were C₁₈/C₁₈ (sn‐1/sn‐2), with octadecapentaenoic [18:5(n‐3)] and octadecatetraenoic [18:4(n‐3)] acid as principal fatty acids. The other cluster contained C₂₀/C₁₈ major forms, with eicosapentaenoic acid [20:5(n‐3)] being the predominant sn‐1 fatty acid. In this study, we have found that Symbiodinium microadriaticum isolated from the jellyfish, Cassiopea xamachana, when grown at 30°C, produced MGDG and DGDG with a more saturated fatty acid, 18:4(n‐3), at the sn‐2 carbon than when grown at 20°C where 18:5(n‐3) predominates. This modulation of the sn‐2 fatty acid's level of saturation is mechanistically similar to what has been observed in Pyrocystis, a C₂₀/C₁₈ dinoflagellate. We have also examined the effect of growth temperature on the betaine lipid, diacylglycerylcarboxyhydroxymethylcholine (DGCC), which has been observed by others to be the predominant non plastidial polar lipid in dinoflagellates. Temperature effects on it were minimal, with very few modulations in fatty acid unsaturation as observed in MGDG and DGDG. Rather, the primary difference seen at the two growth temperatures was the alteration of the amount of minor forms of DGCC, as well as a second betaine lipid, diacylglyceryl‐N,N,N‐trimethylhomoserine.     

Fatty acid composition ofAerobacter aerogenes

The fatty acid composition of the whole cell and cell wall ofAerobacter aerogenes was studied employing column and gas-chromatographic technique. The cell wall contained a greater percentage of total lipid, complex lipid, and free fatty acids compared to the whole cell. Palmitic acid and oleic acid were the most abundant fatty acids found in the free fatty acid and complex lipid fractions. A saturated C₁₇ fatty acid and small quantities of a branched C₁₆ and iso and anteiso C₁₂ fatty acids were detected. The glyceride fractions of the whole cell and cell wall contained very few fatty acids.     

THE LIPID COMPOSITION OF THORACOSPHAERA HEIMII: EVIDENCE FOR INCLUSION IN THE DINOPHYCEAE1

The fatty acid, sterol and chlorophyll composition of the calcified, unicellular alga Thoracosphaera heimii (Lohmann) Kamptner are reported. The presence of 4,23,24-termethyl-5α-cholest-22E-en-3β-ol (dinosterol), 4,23,24-trimethyl-5α-cholest-22E-en-3-one (dinosterone) and the predominance of C₁₈, C₂₀ and C₂₂ unsaturated fatty acids, including the acid 18:5ω3, indicates that T. heimii is a dinoflagellate. The fatty acid: sterol ratio (1.3), is typical of dinoflagellates. The geochemical significance of dinosterone, the high relative concentration of 4-desmethyl-5α-stanols and the role of 23-methyl-5α-cholest-22E-en-3β-ol in the biosynthesis of dinosterol in T. heimii are also discussed.     

Fatty Acids in the Species of Several Zygomycete Taxa

The composition of fatty acids synthesized de novo by thirty strains of zygomycetes from various taxa was studied. The qualitative fatty acid compositions of the fungal lipids were found to be virtually identical, but there were significant differences in the contents of individual acids. Highly active producers of essential C₁₈ fatty acids, with their content exceeding 30–40% of total fatty acids, were discovered among the fungi of the families Mucoraceae, Pilobolaceae, and Radiomycetaceae. Linoleic acid was found to predominate in the fungi of the genera Radiomyces, Mycotypha, and Circinella, and linolenic acid (identified as its -isomer by gas-liquid chromatography), in the fungi of the genera Absidia, Circinella, Pilaira, and Hesseltinella. The total yield (mg/l) of bioactive acids (C_18:3, C_18:2, C_18:1) varied from 761.4 in Pilaira anomala to 3477.9 in Syncephalastrum racemosum; the total yield of essential acids, from 520.7 in Pilaira anomala to 1154.5 in Hesseltinella vesiculosa; of linoleic acid, from 279.7 in Pilaira anomala to 836.3 in Mycotypha indica; and of linolenic acid, from 120.8 in Mycotypha indica to 708.0 in Hesseltinella vesiculosa. The data on the efficient synthesis of these acids make the actively producing strains promising for biotechnological synthesis of commercially valuable lipids. Linderina pennispora VKM F-1219, a zygomycete of the family Kickxellaceae, which was earlier singled out into the order Kickxellales, was shown to differ from zygomycetes of the order Mucorales in having a high content of cis-9-hexadecenoic (palmitoleic) acid, reaching 37.0% of the fatty acid total.     

Resting sporangium of Synchytrium endobioticum: its structure and composition of the lipids and fatty acids

Lipid classes and fatty acid distribution were analysed in the resting sporangium of Synchytrium endobioticum, the causal agent of the potato wart disease. The sporangium contents were shown to have lipid droplets, the major fatty acids there being C_16.0, C_18.1, and C_19.0. The sporangium wall on the other hand was composed of C_18.0, C_18.1, C_18.2, C_20.0, and C_20.4 fatty acids. A significantly large portion of the sporangium wall lipids contained wax esters with branched chains.     

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.     

Transformation of sterols byMycobacterium vaccae: effect of lecithin on the permeability of cell envelopes to sterols

An enhancement of Β-sitosterol transformation to androstendione byMycobacterium vaccae observed in medium containing egg-yolk lecithin, was associated with the incorporation of a considerable amount of lecithin into the cell envelope lipids. By GC/MS measurements, fatty acids ranging from 14 to 22 carbon atoms were identified in the lipids removed from the cells by organic solvents. Octadecenoic (18:1), 2-methyl-octadecenoic (2-Me 18:1), and hexadecanoic (16:0) acids were the major components of the lipid preparation obtained from both the control cells, and the cells grown in lecithin-containing medium. However, in the fatty acid pattern of the latter a distinct increase in the C_18:1 component, concomitant with the decrease in the 2-Me 18:1 fatty acid was demonstrated. The C₁₆ fatty acid fraction also showed a higher content of methyl-branched components in the control cell preparation. The enrichment in unsaturated fatty acids increases fluidity of lipids, whereas the decrease in methyl-branched fatty acids may affect the conformation of the surface lipidic components, which may result in enhanced sterol penetration through the cell wall barrier in the presence of lecithin.     

Synthesis of medium-chain fatty acids and their incorporation into triacylglycerols by cell-free fractions fromCuphea embryos

During their rapid maturation period, seeds of Cuphea wrightii A. Gray mainly accumulate medium-chain fatty acids (C₈ to C₁₄) in their storage lipids. The rate of lipid deposition (40–50 mg·d^–1·(g fresh weight)^–1) is fourfold higher than in seeds of Cuphea racemosa (L. f.) Spreng, which accumulate long-chain fatty acids (C₁₆ to C₁₈). Measurements of the key enzymes of fatty-acid synthesis in cell-free extracts of seeds of different maturities from Cuphea wrightii show that malonyl-CoA synthesis may be a triggering factor for the observed high capacity for fatty-acid synthesis. Experiments on the incorporation of [1-¹⁴C]acetate into fatty acids by purified plastid preparations from embryos of Cuphea wrightii have demonstrated that the biosynthesis of medium-chain fatty acids (C₈ to C₁₄) is localized in the plastid. Thus, in the presence of cofactors for lipid synthesis (ATP, NADPH, NADH, acyl carrier protein, and sn-glycerol-3-phosphate), purified plastid fractions predominantly synthesized free fatty acids, 30% of which were of medium chain length. Transesterification of the freshly synthesized fatty acids to coenzyme A and recombination with the microsomal fraction of the embryo homogenate induced triacylglycerol synthesis. It also stimulated fatty-acid synthesis by a factor 2–3 and increased the relative amount of medium-chain fatty acids bound to triacylglycerols, which corresponded to about 60–80% in this lipid fraction.Abbreviations ACP acyl carrier protein - FW fresh weight This work was supported by the Bundesminister für Forschung und Technologie. The authors thank S. Borchert for her suggestions for plastid preparation.     

Structural Features of Spines in Some Rodents (Rodentia: Myomorpha, Hystricomorpha)

The architectonics of spines and hair was studied in Neacomys spinosus, Tokudaia osimensis, Arvicanthis somalicus, Leopoldamys sabanus, L. edwardsi, Maxomys moi, M. surifer, Niviventer fulvescens, N. confucianus, N. cremoriventer, Acomys cahirinus, A. somalica, Hystrix indica, H. cristata, Atherurus macrourus, Erethizon dorsatum, Proechimys steerei, and Lonchotrix emiliae. The presence of a dorsal longitudinal furrow covered by a modified cuticle is a common structural feature of spines in all studied species except E. dorsatum, H. indica, and H. cristata. The frontal surface of the mosaic (scales located side by side) and terrace cuticle (steps between scales) varies in different species from smooth to rib-folded. A terminology has been proposed to describe the main structures of spine and hair. The adaptive significance of the spine architectonics in rodents is discussed.     

Anti‐Androgenic Activity of Fatty Acids

In this study, we show that 5α‐reductase derived from rat fresh liver was inhibited by certain aliphatic free fatty acids. The influences of chain length, unsaturation, oxidation, and esterification on the potency to inhibit 5α‐reductase activity were studied. Among the fatty acids we tested, inhibitory saturated fatty acids had C₁₂–C₁₆ chains, and the presence of a C?C bond enhanced the inhibitory activity. Esterification and hydroxy compounds were totally inactive. Finally, we tested the prostate cancer cell proliferation effect of free fatty acids. In keeping with the results of the 5α‐reductase assay, saturated fatty acids with a C₁₂ chain (lauric acid) and unsaturated fatty acids (oleic acid and α‐linolenic acid) showed a proliferation inhibitory effect on lymph‐node carcinoma of the prostate (LNCaP) cells. At the same time, the testosterone‐induced prostate‐specific antigen (PSA) mRNA expression was down‐regulated. These results suggested that fatty acids with 5α‐reductase inhibitory activity block the conversion of testosterone to 5α‐dihydrotestosterone (DHT) and then inhibit the proliferation of prostate cancer cells.     

HIGH POLYUNSATURATED FATTY ACID LEVELS IN TWO SUBTROPICAL MACROALGAE,CLADOSIPHON OKAMURANUS AND CAULERPA LENTILLIFERA1

The lipid and fatty acid compositions in two edible subtropical algae (the brown alga Cladosiphon okamuranus Tokida and the green alga Caulerpa lentillifera J. Agardh) were determined to clarify their lipid characteristics and nutritional values. Glycolipids and phospholipids were the major lipid classes, with significant levels of triacylglycerols. Polyunsaturated fatty acids (PUFA) were the major fatty acids of both algae. The lipid class composition and major fatty acids were similar in both the algal species, irrespective of wild and cultured specimens. Typical n‐6 PUFA, such as 18:2n‐6 (linoleic acid) and 20:4n‐6 (arachidonic acid), occurred in characteristically high levels in both of the algae. High levels of n‐3 PUFA were measured in all lipid classes of both species without 22:6n‐3 (docosahexaenoic acid), 18:3n‐3, 18:4n‐3, and 20:5n‐3 (eicosapentaenoic acid) for Cl. okamuranus; and 16:3n‐3, 18:3n‐3, and 20:5n‐3 for Ca. lentillifera. The finding suggests that the green algal species, which mainly biosynthesizes short‐chain (C₁₆ and C₁₈) PUFA, differs from that of the brown alga, which is capable of biosynthesizing high 20:5n‐3 levels. The PUFA levels in glycolipids of the two algal species comprised up to 60%, even though they are subtropical marine species. High n‐6 PUFA levels in the algal lipids probably influence the significant levels of n‐6 PUFA in herbivorous fishes, because the n‐6 PUFA levels in marine fish lipids are generally undetectable or negligible.