Fatty acid ethyl esters in the liverwort Conocephalum conicum

A series of fatty acid ethyl esters ranging from C₁₄ to C₂₄ was isolated from a hexane extract of the liverwort Conocephalum conicum, these esters accounted for 77% of the extract. The ethyl esters consisting of even-numbered fatty acids were predominant and ethyl palmitate was the major constituent.     

Red Algae of Peter the Great Bay as a Source of Arachidonic and Eicosapentaenoic Acids

In order to find new sources of arachidonic (AA) and eicosapentaenoic (EPA) acids, the composition of fatty acids was studied and lipid concentrations were determined in the thalluses of 32 species of red algae from Peter the Great Bay, Sea of Japan. The greatest level of EPA and a small concentration of AA were registered in the thalluses of Corallina pilulifera, Palmaria stenogona, Halosaccion yendoi, and Laurencia nipponica. Taking into consideration the level of the lipid concentrations in the algae, as well as their biomass and frequency of occurrence, the algae C. pilulifera, P. stenogona, L. nipponica, and Polysiphonia morrowii may be of interest as potential sources of EPA. Among the examined algae, only Gracilaria verrucosa showed a high level of AA.     

Lipid composition of sweet cherries

Lipid comprises about 0.1 % of the fresh weight of cherries. The major components of the neutral lipid fraction are wax and sterol esters, sitosterol, oleanolic and ursolic acids. The glycolipid fraction is comprised of monoglycosyldiacylglycerol, diglycosyldiacylglycerol and acylated sterol glycoside, while phosphatidylcholine and phosphatidylethanolamine are the major phospholipids. Palmitic, oleic, linoleic and linolenic acids comprise over 85% of the total fatty acids in each lipid fraction.     

Biohydrogenation of C20 polyunsaturated fatty acids by anaerobic bacteria

The PUFAs include many bioactive lipids. The microbial metabolism of C₁₈ PUFAs is known to produce their bioactive isomers, such as conjugated FAs and hydroxy FAs, but there is little information on that of C₂₀ PUFAs. In this study, we aimed to obtain anaerobic bacteria with the ability to produce novel PUFAs from C₂₀ PUFAs. Through the screening of ∼100 strains of anaerobic bacteria, Clostridium bifermentans JCM 1386 was selected as a strain with the ability to saturate PUFAs during anaerobic cultivation. This strain converted arachidonic acid (cis-5,cis-8,cis-11,cis-14-eicosatetraenoic acid) and EPA (cis-5,cis-8,cis-11,cis-14,cis-17-EPA) into cis-5,cis-8,trans-13-eicosatrienoic acid and cis-5,cis-8,trans-13,cis-17-eicosatetraenoic acid, giving yields of 57% and 67% against the added PUFAs, respectively. This is the first report of the isolation of a bacterium transforming C₂₀ PUFAs into corresponding non-methylene-interrupted FAs. We further investigated the substrate specificity of the biohydrogenation by this strain and revealed that it can convert two cis double bonds at the ω6 and ω9 positions in various C₁₈ and C₂₀ PUFAs into a trans double bond at the ω7 position. This study should serve to open up the development of novel potentially bioactive PUFAs.     

Sesquiterpene hydrocarbons of the liverwort Scapania ornithopodioides

The liverwort, Scapania ornithopodioides, was investigated for sesquiterpene hydrocarbons by utilizing GC and GCIMS and 17 components were identified. Among these, the major component, aromadendrene, and two minor ones, cyclosativene and α-farnesene are reported for the first time as constituents of liverworts. In addition, aromadendrene also occurred in three other Taiwanese liverworts examined.     

Lipid composition and storage in the tissues of the bivalve, Macoma balthica

Total lipid content, lipid classes and fatty acid composition in organs of Macoma balthica (L.) from the Gulf of Gdánsk (Puck Bay) were studied in different seasons. Marked differences among tissues in lipid class composition were observed. Triacylglycerides were accumulated in the hepatopancreas and in the female gonad in large quantities, while hydrocarbons were concentrated in male gonads, gills muscles and mantle. Fatty acid composition of gill lipids reflects the brackish water conditions of the Gulf of Gda sk in which Macoma balthica occurs.     

Lipid composition of adult Foleyella agamae

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& Obiamiwe B. A. 1986. Lipid composition of adult Foleyella agamae. International Journal for Parasitology 16: 655–657. The lipid and fatty acid composition of the filarial parasite Foleyella agamae were investigated. Total lipids accounted for 7.05% of the parasite fresh weight. Neutral lipids comprised 56.34% of the total and polar lipids 43.66%. The major lipid classes detected include sterol esters, cholesterol, phosphatidyl choline and phosphatidyl ethanolamine. Fatty acids varying in chain length from 10 carbon atoms through 20 carbon atoms were identified in the total lipid extract. The 18 carbon fatty acids formed the predominant components. The 20 carbon fatty acids were confined to the polar lipds.     

Molecular mechanism of substrate specificity for delta 6 desaturase from Mortierella alpina and Micromonas pusilla

The ω6 and ω3 pathways are two major pathways in the biosynthesis of PUFAs. In both of these, delta 6 desaturase (FADS6) is a key bifunctional enzyme desaturating linoleic acid or α-linolenic acid. Microbial species have different propensity for accumulating ω6- or ω3-series PUFAs, which may be determined by the substrate preference of FADS6 enzyme. In the present study, we analyzed the molecular mechanism of FADS6 substrate specificity. FADS6 cDNAs were cloned from Mortierella alpina (ATCC 32222) and Micromonas pusilla (CCMP1545) that synthesized high levels of arachidonic acid and EPA, respectively. M. alpina FADS6 (MaFADS6-I) showed substrate preference for LA; whereas, M. pusilla FADS6 (MpFADS6) preferred ALA. To understand the structural basis of substrate specificity, MaFADS6-I and MpFADS6 sequences were divided into five sections and a domain swapping approach was used to examine the role of each section in substrate preference. Our results showed that sequences between the histidine boxes I and II played a pivotal role in substrate preference. Based on our domain swapping results, nine amino acid (aa) residues were targeted for further analysis by site-directed mutagenesis. G194L, E222S, M227K, and V399I/I400E substitutions interfered with substrate recognition, which suggests that the corresponding aa residues play an important role in this process.     

Fatty acid composition of a new marine picoplankton species of the Chromophyta

A marine yellowish picoplankton, strain PP301, which was newly isolated from the surface seawater of the western Pacific Ocean was an eminent producer of polyunsaturated fatty acids. Its fatty acids were mostly shared by the shortest saturated form (14:0, 20–30%) and polyunsaturated forms (20:4, EPA and DHA) which accounted for about 50% of the total fatty acids. The amount of intermediate forms in 16 and 18 carbon chains were very little. This composition was consistently observed irrespective of the growth temperatures (15–35 °C).     

Metabolic Engineering of Plants to Produce Very Long-chain Polyunsaturated Fatty Acids

Very long-chain polyunsaturated fatty acids (VLCPUFAs) are essential for human health and well-being. However, the current sources of these valuable compounds are limited and may not be sustainable in the long term. Recently, considerable progress has been made in identifying genes involved in the biosynthesis of VLCPUFAs. The co-expression of these genes in model systems such as plant embryos or yeast provided many valuable insights into the mechanisms of VLCPUFA synthesis. The recent successful reconstitution of pathways leading to the synthesis of arachidonic acid, eicosapentaenoic acid and finally docosahexaenoic acid in oil-seed plants indicates the feasibility of using transgenic crops as alternative sources of VLCPUFAs. The various approaches used to attain these results and the specific constraints associated with each approach are discussed.     

Taxonomic differences in the essential fatty acid composition of groups of freshwater zooplankton relate to reproductive demands and generation time

1. Marked differences were observed in the total fatty acid concentrations and essential fatty acid (EFA) distributions of co-existing freshwater copepods and cladocerans in four large lake systems (lakes Michigan, Erie, Ontario and Champlain) over two growing seasons. These patterns appeared independent of lake seston EFA composition.
2. Compared to the cladocerans, calanoid and cyclopoid copepods contained significantly higher concentrations of total fatty acids and docosahexaenoic acid (DHA), an EFA abundant in fish. Calanoids and cladocerans contained similar levels of eicosapentaenoic acid (EPA), but cladocerans showed EPA : DHA ratios consistently greater than those of the available seston food source. Alpha-linolenic acid was most abundant in the herbivorous cladocerans, Daphnia and Holopedium , while the highest concentrations of arachidonic acid were found in the predatory cladocerans, Bythotrephes longimanus and Leptodora kindtii .
3. The distinct EFA accumulation patterns between cladoceran and copepod zooplankton suggest metabolic regulation of certain EFAs to meet the particular physiological demands and ecological strategies of these different zooplankton groups. Cladocerans may accumulate EPA directly from their diet, or through transformation of dietary materials to facilitate rapid somatic growth and enhance reproduction due to their short generation time. In contrast, copepods may retain DHA to increase their cell membrane fluidity in order to remain active over the winter due to their longer generation time and life cycle.
4. Consistent EFA differences between zooplankton groups may have implications regarding the somatic growth and reproductive success of different zooplankton taxa as well as the nutritional value of various zooplankton groups for larval and planktivorous fish.     

Role of omega-3 polyunsaturated fatty acids on cyclooxygenase-2 metabolism in brain-metastatic melanoma

Cyclooxygenase-2 (COX-2) is important in the progression of epithelial tumors. Evidence indicates that omega-6 PUFAs such as arachidonic acid (AA) promote the growth of tumor cells; however, omega-3 fatty acids [eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA)] inhibit tumor cell proliferation. We investigated the effects of omega-3 PUFA on the expression and function of COX-2 in 70W, a human melanoma cell line that metastasizes to the brain in nude mice. We show that 1) tumor necrosis factor-alpha upregulates the expression of both COX-2 mRNA and prostaglandin E2 (PGE2) production, and 2) omega-3 and omega-6 PUFA regulate COX-2 mRNA expression and PGE2 production. AA increased COX-2 mRNA expression and prostaglandin production in omega-6-stimulated 70W cells. Conversely, COX-2 mRNA expression decreased in cells incubated with EPA or DHA. AA increased Matrigel invasion 2.4-fold, whereas EPA or DHA did not. Additionally, PGE2 increased in vitro invasion 2.5-fold, whereas exposure to PGE3 significantly decreased invasion. Our results demonstrate that incubation of 70W cells with either AA or PGE2 increased invasiveness, whereas incubation with EPA or DHA downregulated both COX-2 mRNA and protein expression, with a subsequent decrease in Matrigel invasion. Taken together, these results indicate that omega-3 PUFA regulate COX-2-mediated invasion in brain-metastatic melanoma.     

Lunularic acid in cell suspension cultures of Marchantia polymorpha

Lunularic acid (LNA) was isolated from the cultured cells of the liverwort Marchantia polymorpha. Quantitative analysis by reverse phase HPLC showed that the content of LNA in the cells changed markedly during their growth, ranging from 1 to 7μg/mg dry wt. The accumulation of LNA was greatly enhanced by a deficiency of phosphate in the culture medium.     

Lunularic acid decarboxylase from the liverwort Conocephalum conicum

Some properties of a preparation of an enzyme, lunularic acid decarboxylase, from the liverwort Conocephalum conicum are described. The enzyme is normally bound and could be solubilized with Triton X-100; at least some of the bound decarboxylase activity appears to be associated with chloroplasts. For lunularic acid the enzyme has K_m 8.7 × 10^?5 M (pH 7.8 and 30°). Some substrate analogues have been tested but no other substrate was found. Pinosylvic acid is a competitive inhibitor for the enzyme, K_i 1.2 × 10^?4 M (pH 7.8 and 30°). No product inhibition was observed. Lunularic acid decarboxylase activity has also been observed with a cell-free system from Lunularia cruciata.     

Fatty acid content of the dorsal muscle—an indicator of fat quality in freshwater fish

In 56 samples of freshwater fish, most were low in fat, ≤ 5% of dry weight (D.W.), and the sum of all fatty acids (ΣFA) was about 2% of D.W. Trout, whitefish, and grayling had the highest content of the long-chained FA. of ω3 type, EPA and DHA (1·7–2·6% of D.W.). Two large, low-fat pikes with ΣFA of about12–3% of D.W. and a medium-fat whitefish had the highest ω3/ω6 ratios, 8–9, whereas the fattiest fishes, eels from two lakes and the Baltic (ΣFA =17–26% of D.W.) had lower ω3/ω6 ratios, 1·1–1·8 (ω3 and ω6 FA are two important series of FA). The results indicate that ΣA controls the content of saturated FA (SAFA) and monounsaturated FA (MUFA), whereas the polyunsaturated FA (PUFA) was independent of ΣFA after a break point of about 10%ΣFA of D.W. The P/S ratio (PUFA/SAFA) and the PUFA/ΣFA ratio decreased with increased ΣFA, whereas the ω3/ω6 ratio showed no clear correlation to ΣFA. The difference in fatty acid patterns lay between low-fat and high-fat fishes, rather than between marine and freshwater fishes. The variation, both within and between species of the separate FA is small in fish with similar ΣFA content. Also, low-fat and medium-fat fishes tend to be more dietarily favourable than high-fat fishes, when considering the latest criteria for high nutritional value to humans. Abbreviations used in the text: FA, fatty acids; ΣFA, sum of all FA; AA, arachidonic acid (20 : 4ω6); EPA, eicosapentaenoic acid (20 : 5ω3); DHA, docosahexaenoic acid (22 : 6ω3); SAFA, saturated fatty acids; MUFA, monounsaturated fatty acids; PUFA, polyunsaturated fatty acids; D.W., dry weight; F.W. fresh weight; CV, coefficient of variation; ω3 FA, series of PUFA with the first double bond located at carbon number 3; ω6 FA, series of PUFA with the first double bond located at carbon number 6. The fatty acids are described by three numbers, x:ywz, where x=number of carbon atoms, y=number of double bonds, and z=position of the first double bond counted from the methyl end of the molecule.     

Isolation and the structure of deoxopinguisone from the liverwort Ptilidium ciliare

A pure substance has been isolated from the liverwort Ptilidium ciliare of composition C₁₅H₂₂O. On the basis of the correlation of its IR and PMR spectra with those of pinguisone (I), it has been assigned structure of deoxopinguisone (II). This was confirmed by comparison with synthetic deoxopinguisone prepared from authentic pinguisone isolated from Aneura pinguis.     

Identity of Phosphodiesterase and Phosphomonoesterase Activities with Nuclease P1 (a Nuclease from Penicillium citrinum)

Enzymatic properties of a purified Penicillium nuclease (designated as nuclease P₁) were investigated. The enzyme activities for RNA, heat-denatured DNA, native DNA, 3′-AMP and 2′-AMP showed a great degree of similarity with respect to the following properties: a) Range of stable pH (5~8), b) temperature optima (at around 70°C), c) thermostability (about 50% inactivation at 67°C, pH 6.0 for 15 min, d) effect of metal ions and SH inhibitors, e) requirement of Zn²⁺, f) protection from the heat-inactivation by albumin and Zn²⁺, g) inactivation on standing in the cold and reactivation on heating, h) sensitivity to protease, and i) competitive relationship between substrates in the enzyme reaction. Moreover, the ratio of enzyme activities in several mutants of Penicillium citrinum was constant. From these results, together with constant ratio of the specific activities throughout purification, it is concluded that a single enzyme might be responsible for both phosphodiesterase and phosphomonoesterase functions.     

Lipid synthesis by germinating soya bean

Lipid content and changes during the first 2 days of germination have been examined in soya bean Glycine max (L.) Merr variety Fiskeby V. Triacylglycerol, the principle storage lipid, is reduced on germination and this is accompanied by a rise in phospholipid content. The relative amounts of phospholipids rise equally, apart from the disappearance of N-acylphosphatidylethanolamine and significant increases in the proportions of phosphatidic acid and phosphatidylglycerol.Incorporation of acetate-[¹⁴C] into lipids occurs after a brief lag phase. Labelling is almost entirely (94–100%) confined to the acyl portion of the major complex lipids. Triacylglycerols had low specific radioactivities and, of the phospholipids, phosphatidylglycerol, cardiolipin, and phosphatidylinositol had the highest specific radioactivities. Incorporation was somewhat reduced by protein synthesis inhibitors and was mainly into palmitic, stearic and oleic acids. There were minor differences in their distribution within lipid types.     

Effect of cell density and irradiance on growth,proximate composition and eicosapentaenoic acid production ofPhaeodactylum tricornutum grown in a tubular photobioreactor

Growth and eicosapentaenoic acid (EPA) productivity of the diatomPhaeodactylum tricornutum grown semicontinuously in a helical tubular photobioreactor were examined under a range of irradiances (approximately 56 to 1712 µmol photons m^-2 s^-1) and cell densities (3 × 10⁶ to 18 × 10⁶ cells mL^-1). Self shading sets the upper limit of operational maximum cell density. Higher irradiance increases this upper limit and also increase the growth rate. Biomass productivity and EPA productivity were enhanced at those cell densities which support the fastest growth rate irrespective of irradiance. The cell protein content increased with increasing irradiance and the carbohydrate and lipid content increased with increasing cell density. EPA productivity was greatest at the highest irradiance. This study shows that biomass productivity and EPA productivity can be maximised by optimising cell density and irradiance, as well as by addition of CO₂.Author for correspondence