High contents of 24:6(n-3) and 20:1(n-13) fatty acids in the brittle star Amphiura elandiformis from Tasmanian coastal sediments

The presence of long-chain polyunsaturated fatty acids (PUFA; ca. 9% of total fatty acids) in marine sediments near Dover, southern Tasmania, Australia prompted a search for their likely source. Analysis of a number of different species of benthic fauna isolated from these sediments revealed that the brittle star Amphiura elandiformis contained abundant PUFA including high contents of the uncommon long-chain fatty acid 24:6(n-3), but much smaller amounts of the more common animal PUFA 22:6(n-3). This is the first report of the lipid composition of this animal. Identifications of the unsaturated fatty acids were confirmed by formation of DMOX derivatives which gave characteristic and easily interpreted mass spectra. The 24:6(n-3) PUFA has been identified in some genera of brittle stars, but not others. It is rarely found in significant amounts in other marine animals. DMDS adducts were used to identify the positions of double bonds in the monounsaturated fatty acids. The major 20:1 isomer was identified as the rarely reported 20:1(n-13) fatty acid. The two fatty acids 20:1(n-13) and 24:6(n-3) may be useful biomarkers in food-web studies for identifying a brittle star diet and for recognising contributions of organic detritus from this benthic animal to marine sediments.     

An alternative to fish oils: Metabolic engineering of oil-seed crops to produce omega-3 long chain polyunsaturated fatty acids

It is now accepted that omega-3 polyunsaturated fatty acids, especially eicosapentaenoic acid (EPA; 20:5Δ5,8,11,14,17) and docosahexaenoic acid (DHA, 22:6Δ4,7,10,13,16,19) play important roles in a number of aspects of human health, with marine fish rich in these beneficial fatty acids our primary dietary source. However, over-fishing and concerns about pollution of the marine environment indicate a need to develop alternative, sustainable sources of very long chain polyunsaturated fatty acids (VLC-PUFAs) such as EPA and DHA. A number of different strategies have been considered, with one of the most promising being transgenic plants “reverse-engineered” to produce these so-called fish oils. Considerable progress has been made towards this goal and in this review we will outline the recent achievements in demonstrating the production of omega-3 VLC-PUFAs in transgenic plants. We will also consider how these enriched oils will allow the development of nutritionally-enhanced food products, suitable either for direct human ingestion or for use as an animal feedstuff. In particular, the requirements of aquaculture for omega-3 VLC-PUFAs will act as a strong driver for the development of such products. In addition, biotechnological research on the synthesis of VLC-PUFAs has provided new insights into the complexities of acyl-channelling and triacylglycerol biosynthesis in higher plants.     

Fatty acid composition of four microsporidian species compared to that of their host fishes

ABSTRACT. The fatty acid composition of four microsporidian species (Glugea atherinae, Spraguea lophii, Glugea americanus , and Pleistophora mirandellae) and their host fishes has been determined using gas chromatography. Twenty-four fatty acids were identified with differences in relative abundance of fatty acids among the four parasites. Certain even-saturated fatty acids were found in a very high proportion: palmitic acid (16:0) represented one-third of total fatty acids in Pleistophora mirandellae. The level of docosahexaenoic acid (22:6ω3) attained 26–28% in Glugea atherinae, Spraguea lophii , and Glugea americanus , but only 8–9% in P. mirandellae. With respect to fatty acid compositions of host organs, some significant differences were evident between marine and freshwater fishes. Palmitic acid was prevalent in the marine fishes, Atherinae boyeri and Lophius piscatorius , and oleic acid (18:1ω9) in the freshwater fish Leuciscus cephalus. The proportion of docosahexaenoic acid in marine fishes was two or three times as great as in freshwater fish Leuciscus. The high polyunsaturated fatty acid content in both parasites and host fishes may be related to the scavenging of these fatty acids by the parasites rather than a microsporidia-specific fatty acid biosynthesis pathway.     

Marine Natural Products: The Important Resource of Biological Insecticide

Due to the unique environmental conditions and vast territory, marine habitat breeds more abundant biological resources than terrestrial environment. Massive marine biological species provide valuable resources for obtaining a large number of natural products with diverse structure and excellent activity. In recent years, new breakthroughs have been made in the application of marine natural products in drug development. In addition, the use of marine natural products to develop insecticides and other pesticide products has also been widely concerned. Targeting marine plants, animals, and microorganisms, we have collected information on marine natural products with insecticidal activity for nearly decade, including alkaloids, terpenes, flavonoids and phenols fatty acids, peptides, and proteins, et al. In addition, some active crude extracts are also included. This review describes the insecticidal activities of marine natural products and their broad applications for future research in agriculture and health.     

New advances in the chemistry of methoxylated lipids

Methoxylated lipids have been reviewed emphasizing the alkylglycerol ethers and fatty acids bearing the methoxy group in the alkyl chain. The literature on methoxylated lipids and their derivatives has been divided into four main groups, namely 2-methoxylated alkyl glycerols, ω-methoxylated fatty acids, mid-chain methoxylated fatty acids, and -methoxylated fatty acids. The natural occurrence, biological activity, and synthesis of this interesting group of lipids are discussed. Most of these compounds have been isolated from either bacterial or marine sources, but others are mainly of synthetic origin. Among the interesting biological activities displayed by these compounds the most important are antibacterial, antifungal, antitumor, and antiviral.     

Starvation Response of the Marine Barophile CNPT-3

The psychrophilic marine barophile CNPT-3 underwent a starvation-survival response similar to that reported for the marine bacteria Ant-300, DW1, and S-14. The number of culturable cells increased initially and then decreased gradually over a 24-day starvation period, with corresponding decreases in total cell number and direct viability count. A significant reduction in cell size and biovolume accompanied these changes. Starved cells demonstrated a greater tendency to attach at the in situ pressure (400 atm; ca. 40.5 MPa) and temperature (5°C) than at 1 atm (ca. 101 kPa), and the extent of attachment increased with increasing duration of starvation. The membrane fatty acid profile of the marine barophile CNPT-3 was studied as the cells were subjected to starvation conditions. A 37.5% increase in saturated fatty acids was observed during the first 8 days of starvation, with a concomitant decrease in unsaturated fatty acids. There was also an increase in the amount of short-chain (<C_15:0) fatty acids.     

The fatty acids of the sponge Hymeniacidon sanguinea from the Black Sea

The fatty acid composition of the sponge Hymeniacidon sanguinea from the Black Sea has been determined by methods involving silver ion HPLC and GC-MS. More than a hundred different fatty acids were identified, of which many were similar to those in sponges from tropical seas. By contrast, some of the fatty acids identified, including trans-6-hexadecenoic acid and 5,15-tetracosadienoic acid, may not have been found previously in sponges and other marine sources, and perhaps are new to science.     

Multi-component analysis of marine lipids in fish gonads with emphasis on phospholipids using high resolution NMR spectroscopy

High resolution NMR has been applied for assessment of lipid classes and acyl stereospecific positions of fatty acids in marine phospholipids and triacylglycerols. 1D and 2D NMR techniques in combination with recording of a number of reference standards have been used to interpret the (1)H and (13)C NMR spectra of fish gonads. (13)C NMR spectra gave information regarding the polyunsaturated fatty acids (PUFAs) in phosphatidylcholine (PC) and phosphatidylethanolamine (PE). The carbonyl resonances showed that n-3 PUFAs primarily were esterified in the sn-2 position of PC and PE. The glycerol resonances showed that the PC/PE ratio was higher in roe than in milt and that roe comprised more triacylglycerols than milt. Thin layer chromatography showed that milt contained 2.4 times more cholesterol than roe, which was also found by integrating the (1)H NMR spectra. Concentration (mol%) of n-3 fatty acids were calculated from the (1)H NMR data and showed 44.8 and 36.3% in roe and milt, respectively.     

N-alkane biodegradation by a marine bacterium in the presence of an oleophilic nutriment

Summary Hexadecane biodegradation by a marine bacterium has been investigated in the presence of an oleophilic nutriment (INIPOL EAP 22). Hydrocarbon attack was only observed after metabolism of the fatty acids present in the fertilizer. The bacterium used up 95 % fatty acids in the first 24 hours. Hexadecane biodegradation took place after 50 h incubation and reached 40 % after 360 h.     

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.     

C6-aldehyde formation by fatty acid hydroperoxide lyase in the brown alga Laminaria angustata

Some marine algae can form volatile aldehydes such as n-hexanal, hexenals, and nonenals. In higher plants it is well established that these short-chain aldehydes are formed from C18 fatty acids via actions of lipoxygenase and fatty acid hydroperoxide lyase, however, the biosynthetic pathway in marine algae has not been fully established yet. A brown alga, Laminaria angustata, forms relatively higher amounts of C6- and C9-aldehydes. When linoleic acid was added to a homogenate prepared from the fronds of this algae, formation of n-hexanal was observed. When glutathione peroxidase was added to the reaction mixture concomitant with glutathione, the formation of n-hexanal from linoleic acid was inhibited, and oxygenated fatty acids accumulated. By chemical analyses one of the major oxygenated fatty acids was shown to be (S)-13-hydroxy-(Z, E)-9, 11-octadecadienoic acid. Therefore, it is assumed that n-hexanal is formed from linoleic acid via a sequential action of lipoxygenase and fatty acid hydroperoxide lyase (HPL), by an almost similar pathway as the counterpart found in higher plants HPL partially purified from the fronds has a rather strict substrate specificity, and only 13-hydroperoxide of linoleic acid, and 15-hydroperoxide of arachidonic acid are the essentially suitable substrates for the enzyme. By surveying various species of marine algae including Phaeophyta, Rhodophyta and Chlorophyta it was shown that almost all the marine algae have HPL activity. Thus, a wide distribution of the enzyme is expected.     

trans-Monounsaturated Acids in a Marine Bacterial Isolate

A sedimentary bacterial isolate has been shown to contain trans-monounsaturated fatty acids (6% of the total fatty acids). The ratio of trans- to cis-acids in this isolate was in the range 3.2 to 7.6. The identification of trans-monounsaturated acids in a marine bacterium implied that the trans-acids which have been reported in recent sediments could derive, in whole or part, from direct bacterial input.     

Variation of lipid and fatty acid compositions of the marine microalga Pavlova viridis (Prymnesiophyceae) under laboratory and outdoor culture conditions

The marine microalga Pavlova viridis (Prymnesiophyceae) is widely used in marine aquaculture industries of China for feeding bivalves and has been proposed as an alternative source of eicosapentaenoic acid (EPA). To investigate variation of its lipid and fatty acid compositions during laboratory and outdoor cultivation, a 60-1 photobioreactor was established in Nanjing, China. Outdoor cultivation, paralleled with laboratory cultures in mid-October, was performed from autumn through midwinter. The results showed that the total lipid and EPA contents of outdoor cultures were both lower than those of indoor cultures. When the outdoor temperature and illumination decreased, total lipid experienced no significant change. Although the level of saturated fatty acids decreased, polyunsaturated fatty acids, especially EPA, increased.     

Microalgal biofactories: a promising approach towards sustainable omega-3 fatty acid production

ABSTRACT: Omega-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) provide significant health benefits and this has led to an increased consumption as dietary supplements. Omega-3 fatty acids EPA and DHA are found in animals, transgenic plants, fungi and many microorganisms but are typically extracted from fatty fish, putting additional pressures on global fish stocks. As primary producers, many marine microalgae are rich in EPA (C20:5) and DHA (C22:6) and present a promising source of omega-3 fatty acids. Several heterotrophic microalgae have been used as biofactories for omega-3 fatty acids commercially, but a strong interest in autotrophic microalgae has emerged in recent years as microalgae are being developed as biofuel crops. This paper provides an overview of microalgal biotechnology and production platforms for the development of omega-3 fatty acids EPA and DHA. It refers to implications in current biotechnological uses of microalgae as aquaculture feed and future biofuel crops and explores potential applications of metabolic engineering and selective breeding to accumulate large amounts of omega-3 fatty acids in autotrophic microalgae.     

Cultivation of Microorganisms in the Cultural Medium Made from Squid Internal Organs and Accumulation of Polyunsaturated Fatty Acids in the Cells

The disposal and more efficient utilization of marine wastes is becoming increasingly serious. A culture media for microorganisms has been prepared from squid internal organs that are rich in polyunsaturated fatty acids (PUFAs). Both freshwater and marine bacteria grew well in this medium and some bacteria accumulated PUFAs in their lipids, suggesting uptake of exogenous PUFAs. Higher PUFA accumulations were observed in Escherichia coli mutant cells defective either in unsaturated fatty acid biosynthesis or fatty acid degradation, or both, compared to those without these mutations. Therefore, PUFA accumulation in cells can be improved by genetic modification of fatty acid metabolism in the bacteria. Squid internal organs would be a good source of medium, not only for marine bacteria but also for freshwater bacteria, and that this process may be advantageous to make efficient use of the fishery wastes and to produce PUFA-containing microbial cells and lipids.     

Metabolic engineering of the omega-3 long chain polyunsaturated fatty acid biosynthetic pathway into transgenic plants

Omega-3 (ω-3) very long chain polyunsaturated fatty acids (VLC-PUFAs) such as eicosapentaenoic acid (EPA; 20:5 Δ5,8,11,14,17) and docosahexaenoic acid (DHA; 22:6 Δ4,7,10,13,16,19) have been shown to have significant roles in human health. Currently the primary dietary source of these fatty acids are marine fish; however, the increasing demand for fish and fish oil (in particular the expansion of the aquaculture industry) is placing enormous pressure on diminishing marine stocks. Such overfishing and concerns related to pollution in the marine environment have directed research towards the development of a viable alternative sustainable source of VLC-PUFAs. As a result, the last decade has seen many genes encoding the primary VLC-PUFA biosynthetic activities identified and characterized. This has allowed the reconstitution of the VLC-PUFA biosynthetic pathway in oilseed crops, producing transgenic plants engineered to accumulate ω-3 VLC-PUFAs at levels approaching those found in native marine organisms. Moreover, as a result of these engineering activities, knowledge of the fundamental processes surrounding acyl exchange and lipid remodelling has progressed. The application of new technologies, for example lipidomics and next-generation sequencing, is providing a better understanding of seed oil biosynthesis and opportunities for increasing the production of unusual fatty acids. Certainly, it is now possible to modify the composition of plant oils successfully, and, in this review, the most recent developments in this field and the challenges of producing VLC-PUFAs in the seed oil of higher plants will be described.     

脂肪酸对中华哲水蚤摄食两种海洋微藻的指示作用

在室内以饥饿培养为对照,以海洋原甲藻(Prorocentrum micans)和中肋骨条藻(Skeletonema costatum)培养中华哲水蚤(Calanus sinicus),研究了各脂肪酸标记对中华哲水蚤摄食不同饵料的指示作用。结果显示,海洋原甲藻中18 ∶ 4ω3、22 ∶ 6ω3含量较高,中肋骨条藻中16 ∶ 1ω7、20 ∶ 5ω3的含量较高。二者分别表现出典型的甲藻门和硅藻门的脂肪酸组成特征。中华哲水蚤的脂肪酸组成有两个特点:(1)20 ∶ 5ω3和22 ∶ 6ω3的含量均较高;(2)其体内表征桡足类浮游植物食性、由桡足类自身合成的20 ∶ 1和22 ∶ 1脂肪酸占有相当的比例。虽然中华哲水蚤对不同脂肪酸的吸收和转化效率不同,但以脂肪酸作为标记还是成功的指示了中华哲水蚤对微藻的摄食。在饥饿培养中,首先消耗的是那些浮游动物自身不能合成的多不饱和脂肪酸,而结构脂肪酸都表现出了较高的保守性。结合各脂肪酸标记变化趋势和Pearson相关性分析的结果认为,18 ∶ 4ω3、18 ∶ 4ω3/16 ∶ 1ω7、∑18/∑16能较好的指示中华哲水蚤对海洋原甲藻的摄食,仅16 ∶ 1ω7/18 ∶ 4ω3能指示中华哲水蚤对中肋骨条藻的摄食。     

Characterization of cerebroside (monoglycosylceramide) from the sea anemone, Metridium senile. Identification of the major long-chain base as an unusual dienic base with a methyl branch at a double bond.

1. Cerebroside of the sea anemone, Metridium senile, has been isolated (0.6 mg/g dry tissue weight) and structurally characterized. 2. The structure was shown by mass spectrometry, NMR spectroscopy and degradative studies as beta-glucopyranosylceramide. The major fatty acids were 16 : 0 and 20 : 0 D-2-hydroxy fatty acids. The major base was a novel base, D-erythro-1,3-dihydroxy-2-amino-9-methyl-trans-4, trans-8-octadecadiene. 3. Some unusual fatty acids of marine origin are suggested to originate in this long-chain base by metabolic conversion. 4. The implication of the methyl branch position of the base on our current view of sphingolipid function in the plasma membrane is discussed.     

Response of Pyropia haitanensis to agaro-oligosaccharides evidenced mainly by the activation of the eicosanoid pathway

The marine red alga Pyropia haitanensis (Protoflorideophyceae, Bangiaceae) has a nonvascular and multicellular structure and emerged earlier in evolution than other cultivatable red algae. It has been reported that lipid mediators from both the eicosanoid and octadecanoid pathways are involved in the innate immunity of other marine algae. But the defense strategies of P. haitanensis are not clearly understood. Here, we investigated the lipid defense of P. haitanensis elicited by agaro-oligosaccharides. The results indicate that the resistance of P. haitanensis was elicited and hydrogen peroxide was released by agaro-oligosaccharides. In P. haitanensis, C20 fatty acids are the essential fatty acids. Phospholipase A₂ was activated, and the free fatty acids decreased 3 h after treatment with agaro-oligosaccharides. Gas chromatography–mass spectrometry analyses revealed that the contents of volatile organic compounds increased after treatment for 3 h, which indicated that these free fatty acids were metabolized to volatile organic compounds. In conclusion, the lipid metabolic defense pathway of P. haitanensis was mainly via the C20 metabolism pathway. The C20 fatty acid was rapidly metabolized to volatile organic compounds, but not oxidized to oxylipins in response to agaro-oligosaccharides.     

海洋真菌产油脂中DHA含量的准确快速测定

选用DB-23毛细管色谱柱,设置合适的载气压力,采用气相色谱(GC)分析了海洋真菌中脂肪酸的组成,并对二十二碳六烯酸(DHA)进行了定量分析。测定结果表明:能有效分离37种脂肪酸,分析时间仅需20min,DHA的回收率为96.95%～100.22%,相对标准偏差为1.33%,海洋真菌中DHA的含量为365.78mg/g,相对标准偏差为2.54%。