The Manipulation of the Fatty Acid Composition of Glycerolipids in Cyanobacteria Using Exogenous Fatty Acids

The fatty acid composition of the major diacylglycerolipidsof Anacystis nidulans R2 cells was modified by the careful additionof exogenous fatty acids to the growth medium of the cyanobacteria.In this way it is possible to incorporate significant levelsof different fatty acids into the membranes of the cells andchange their physical properties without changing other environmentalconditions. The exogenous fatty acid reduces or inhibits thebiosynthesis of native fatty acids and substitutes for themin all the major diacylglycerolipids. Although modifying thefatty acid composition in this way is lethal above certain concentrations,the data demonstrate a remarkable ability of the cells to growand develop over a wide range of fatty acid compositions. Similardata show that the fatty acid composition of Synechocystis sp.6803 cells also undergo significant changes in fatty acid compositionon the addition of exogenous fatty acid to the growth mediumand can tolerate similar changes in the degree of unsaturationof the fatty acids of the diacylglycerolipids of the cell membranes. (Received September 4, 1989; Accepted March 13, 1990)     

Fatty Acid Composition of Phosphatidylglycerols in Relation to Chilling Sensitivity of Woody Plants

The fatty acid composition of phosphatidylglycerol (PG) wasexamined in leaves of nine species of temperate-zone evergreens,seven species of tropical evergreens and seven species of temperate-zonedeciduous plants. The sum of the levels of palmitate, stearateand trans-3-hexadecenoate, as a percentage of the total fattyacids in the PG, ranged from 55% to 62% in the temperate-zoneevergreens, from 67% to 75% in the tropical evergreens, andfrom 58% to 72% in the temperate-zone deciduous plants. Thesefindings suggest that the sum of the saturated and trans-monounsaturatedmolecular species, relative to the total fatty acids in PG,is correlated with the sensitivity of the leaves of evergreensto chilling, being consistent with the hypothesis proposed toexplain the sensitivity to chilling of leaves of herbaceousplants. (Received December 8, 1989; Accepted March 23, 1990)     

Characterization of Sulfoquinovosyl Diacylglycerol from Marine Red Algae

Sulfoquinovosyl diacylglycerol (SQDG) from a red alga, Gracilariaverrucosa, contained high levels of saturated fatty acids, palmiticand myristic acids. The lipid was separated by normal-phasethin-layer chromatography (TLC) into two spots which differedin terms of the color generated by the anthron reagent and interms of constituent fatty acids. However, chromato-graphicand spectrometric (NMR and IR) analyses indicated that boththe upper and the lower fractions were SQDG. The upper fractionwas mainly composed of 20:4/16:0 species, while the major speciesin the lower fraction was mainly 14:0/16:0 and 16:0/16:0. Comparisonof mobilities of SQDG from various sources by TLC confirmedthat the chain length of acyl groups significantly affectedthe Rf value. The short-chain saturated acid species of SQDGwas also detected in marine red algae, Gracilaria textorii,Gelidium amansii, Chondrus ocellatus and Chon-dria crassicaulis. (Received December 9, 1988; Accepted May 10, 1989)     

Mouse GPR40 heterologously expressed in Xenopus oocytes is activated by short-, medium-, and long-chain fatty acids

Several orphan G protein-coupled receptors, including GPR40, have recently been shown to be responsive to fatty acids. Although previous reports have suggested GPR40 detects medium- and long-chain fatty acids, it has been reported to be unresponsive to short chain fatty acids. In this study, we have heterologously expressed mouse GPR40 in Xenopus laevis oocytes and measured fatty acid-induced increases in intracellular Ca²⁺, via two electrode voltage clamp recordings of the endogenous Ca²⁺-activated chloride conductance. Exposure to 500 µM linoleic acid (C18:2), a long-chain fatty acid, stimulated significant currents in mGPR40-injected oocytes (P < 0.01, ANOVA), but not in water-injected control oocytes (not significant, ANOVA). These currents were confirmed as Ca²⁺-activated chloride conductances because they were biphasic, sensitive to changes in external pH, and inhibited by DIDS. Similar currents were observed with medium-chain fatty acids, such as lauric acid (C12:0) (P < 0.01, ANOVA), and more importantly, with short-chain fatty acids, such as butyric acid (C4:0) (P < 0.01, ANOVA). In contrast, no responses were observed in mGPR40-injected oocytes exposed to either acetic acid (C2:0) or propionic acid (C3:0). Therefore, GPR40 has the capacity to respond to fatty acids with chain lengths of four or greater. This finding has important implications for understanding the structure:function relationship of fatty acid sensors, and potentially for short-chain fatty acid sensing in the gastrointestinal tract. fatty acid chain length; nutrient sensing     

Effect of Thiolactomycin on Fatty Acid Synthesis in Higher Plants

Thiolactomycin (TLM), an antibiotic from Nocardia sp. No. 2-200,inhibited fatty acid synthesis in Avena leaves, with the concentrationcausing 50% inhibition being 0.38µg/ml. This antibioticis more inhibitory to the elongation of palmitic to oleic acidthan to the de novo synthesis of palmitic acid in both spinachchloroplasts and Avena leaves, in contrast to the effect ofcerulenin which inhibits de novo synthesis but not fatty acidelongation. On the other hand, TLM is less inhibitory to furtherelongation of stearic acid to very long chain fatty acids inpea seeds. The inhibition rate decreased in the order of synthesisof arachidic, behenic and lignoceric acid. (Received December 26, 1986; Accepted April 24, 1987)     

Fatty Acids in Chloroplasts and Leaves

The fatty acid composition of green and white leaf tissue inAcer negundo, Zea mais, and Ilex aquifolium, of green and yellowtissue in Ligustrum ovatifolium and of etiolated and green tissuein Vicia faba has been determined. The mesophytic green leavesexamined show a general similarity in fatty acid composition,characterized by a high concentration of non-conjugated octadecatrienoicacid. Chloroplasts were isolated from Vicia and Acer and containan even higher concentration of this acid and only traces ofnon-conjugated octadecadienoic acid. Conjugated diene and trieneacids occur in traces in chioroplasts, but are also found innon-green leaf tissue. The fats of non-green leaves are in generalmore saturated than those from green tissue but vary considerablyin composition. The relationship between fat composition andplastid development is discussed.     

Induction of Browning of Male Flowers of Cryptomeria japonica by Treatment with Fatty Acids: Mechanism and the Role of trans-2-Hexenal

The effect of treatment with fatty acids on the browning ofmale flowers of Cryptomeria japonica and its mechanism werestudied with emphasis on the role of trans-2-hexenal. The effectof treatment with fatty acids on the browning of male flowerswas the highest when fatty acids were applied at the end ofAugust, decreasing month by month thereafter in parallel withthe seasonal changes in lipoxygenase activity. trans-2-Hexenal,which is formed from linolenic acid in a reaction catalyzedby lipoxygenase (EC 1.13.1.13 [EC] ), stimulated the evolution ofethylene and acetaldehyde in male flowers predominantly, withresultant enhancement of the activity of phenylalanine ammonia-lyase(EC 4.3.1.5 [EC] ), and the browning of male flowers. A possible biochemicalpathway for browning of male flowers of Cryptomeria japonicais discussed. (Received September 19, 1994; Accepted September 7, 1995)     

Breeding for Short-stemmed Oil Palm in Nigeria: Fatty Acids, their Significance and Characteristics

The fatty acids of the progenies arising from the first back-crossfrom Elaeis guineensis and Elaeis oleifera interspecific hybridsto E. guineensis have been characterized. Fatty-acid patternsshowed striking variability which indicated that factors governingfatty-acid inheritance are polygenic. Although segregation forindividual fatty acids had no relationship with the large numberof morphological characters observed, a definite upward trendin the percentage of unsaturated fatty acids was clearly showncompared to the parent palms. The commercial and domestic advantagesof unsaturated fatty acids are discussed. Elaeis guineensis, oil palm, breeding, fatty acid content     

Seasonal and developmental variation in the fatty acid composition of Mysis mixta (Mysidacea) and Acanthostepheia malmgreni (Amphipoda) from the hyperbenthos of a cold-ocean environment (Conception Bay, Newfoundland)

Fatty acid composition in different life-history stages of Mysismixta (Crustacea, Mysidacea) and Acanthostepheia malmgreni (Crustacea,Amphipoda) from Conception Bay, Newfoundland, was examined throughout1999 and 2000. The primary aim was to relate the seasonal fattyacid dynamics to each species’ life cycle and to publishedinformation on the occurrence and quality of the annual phytoplanktonbloom. Divergent patterns in fatty acid composition and specificfatty acid marker ratios reflected different life styles, dietsand critical periods of energy accumulation and utilizationin M. mixta and A. malmgreni. Changes in fatty acids reflectedthe sequence of plankton taxa during and following the springbloom, starting with diatoms and dinoflagellates and endingwith copepods. Immature mysids exhibited a particularly rapidaccumulation of diatom-associated fatty acids at the start ofthe spring bloom, probably owing to the high degree of motilityof M. mixta and the broad range of prey types available to thisspecies. In contrast, immature amphipods did not begin to accumulatesignificant amounts of phytoplankton fatty acids until afterthe spring bloom material had settled to the hyperbenthos inMay. Differences in fatty acid composition indicated that A.malmgreni was restricted to a lower quality diet than was M.mixta and that the trophic connection between A. malmgreni andproduction in the euphotic zone was weaker.     

Effect of Thiolactomycin on Lipid Synthesis in Higher Plants

The effect of thiolactomycin (TLM), an inhibitor of type IIfatty acid synthase, on lipid synthesis in greening tissueswas examined. Pulse-chase experiments with Na[1-¹⁴C]acetatefor greening Avena leaves showed that continuous administrationof TLM (100µg/ml) decisively reduced phosphatidylcholine(PC) synthesis from acetate and blocked the subsequent conversionof PC to monogalactocyldiacylglycerol (MGDG), whereas temporaladministration of TLM (100 µ/ml) reduced PC synthesisfrom acetate by only 50% and did not block the conversion ofPC to MGDG. In the reduced PC synthesis, the ratio of oleicto palmitic acid decreased at earlier stages of greening, reflectingmore suppression of oleic acid synthesis. In later greeningstages the modulated fatty acid composition recovered to thenormal composition. In further steps, the fatty acid compositionwas not affected by TLM throughout the greening stages. Greeningof either etiolated Avena leaves or etiolated Brassica cotyledonsin the presence of TLM led to a marked decrease in the contentsof MGDG, digalactosyldiacylglycerol (DGDG) and phosphatidylglycerol(PG), but only a small change in the fatty acid compositionof their lipids. The only inhibition characteristic of TLM wasthe desaturation of palmitic to 3-trans-hexadecenoic acid inAvena leaf PG. These results suggest the presence of a mechanismby which the modulated fatty acid composition of lipids is normalizedin the flow of the synthesis. Electron microscopic observationsshowed that Avena chloroplasts developed into round forms ratherthan normal ellipse forms and the thylakoid membranes of Brassicachloroplasts were abnormally swollen everywhere in the presenceof TLM. Photosynthetic oxygen evolution in both tissues wasnot inhibited. (Received December 26, 1986; Accepted April 24, 1987)     

Changes in Endogenous Fatty Acids and Lipid Synthesis Associated with Copper Pollution in Fucus spp

Fatty acid synthesis from [¹⁴C]acetate was studied in the brownalgae, Fucus serratus and Fucus vesiculosus, which had beencollected from sites polluted by run-off from old copper mines.Algae collected from areas exposed to copper in situ showedchanges in the pattern of fatty acids labelled in vitro withan increase in oleate labelling and a decrease in palmitatelabelling in both species. The endogenous fatty acid patternsfor algae from polluted sites also differed from those fromunpolluted sites. Algae from sites polluted by copper containedmore oleate than samples from non-polluted sites. In addition,there were decreases in the polyunsaturated fatty acids -linolenate,octadecatetraenoate and docosapentaenoate for copper-exposedalgae. These differences are discussed with regard to the possiblemetabolic site of copper's action and to the relative toleranceof Fucus spp. to high environmental dissolved copper levels. Key words: Fucus spp., Copper pollution, Fatty acid synthesis     

Selective Inhibition of Type II Fatty Acid Synthetase by the Antibiotic Thiolactomycin

The antibiotic thiolactomycin inhibits the fatty acid synthesisfrom both [1-¹⁴C]- acetate and [2-¹⁴C]malonyl-CoA of spinachleaves, developing castor bean endosperms and avocado mesocarp.On the other hand, fatty acid synthetases of Brevibacteriumammoniagenes and Corynebacterium glutamicum are much less sensitiveto this antibiotic. As has been indicated that thiolactomycininhibits fatty acid synthetase of Escherichia coli but has littleeffect on the synthetases of yeast and rat liver [Hayashi etal. (1983) Biochem. Biophys. Res. Commun.. 115: 1108], thiolactomycinis suggested to be a selective inhibitor of type II fatty acidsynthetases. (Received November 10, 1983; Accepted December 17, 1983)     

Lipids in Acanthodiaptomus denticomis during starvation and fed on three different algae

Variations in the levels of triglycerides, wax esters and polarlipids were determined in adults of the calanoid copepod Acanthodiaptomusdenticornis when freshly caught, starved or fed on the followingalgae: Anabaena spiroides, Cyclotella pseudostelligera and Pediastrumduplex. Over 7 days starvation, triglycerides and wax esterswere almost entirely used up by the copepods. Subsequent feedingover 20 days partially restored triglycerides but restored onlya relatively small fraction (<20%) of wax esters in the animals.Differences in the lipid restoration were found: the restoredtriglyceride level was higher in animals feeding on Cyclotellapseudostelligera or Pediastrum duplex than in those feedingon Anabaena spiroides. Fatty acid composition of neutral lipidswas closely linked to fatty acid composition of algae. The resultssuggest that lipid and fatty acid contents of Acanthodiaptomusdenticornis are good indices of the copepod's nutritional statusand short-term (0–20 days) feeding history.     

Differential Effects of the Substituted Pyridazinone Herbicide Sandoz 9785 on Lipid Composition and Biosynthesis in Photosynthetic and Non-Photosynthetic Marine Microalgae: II. FATTY ACID COMPOSITION

The effect of the substituted pyridazinone, 4-chloro-5-(dimethylamino)-2-phenyl-3(2H)-pyridazinone(Sandoz 9785), on fatty acid synthesis in two photosyntheticspecies (Chroomonas salina and Nannochloropsis oculata) andone non-photosynthetic species (Crypthecodiniun cohnii) of marinemicroalgae were examined. Effects were more obvious in C. salinathan in C. cohnii or N. oculata. In C. cohnii the relative distributionamongst polyunsaturated fatty acids (PUFA) of radioactivityincorporated from ¹⁴C-acetate was not influenced by the herbicideto any great extent and no major changes in the fatty acid compositionof lipid fractions were observed. In C. salina, Sandoz 9785reduced the proportions of radioactivity recovered in 20: 5(n–3) and 22: 6 (n–3) of the phospholipid fraction.The distribution pattern of radioactivity in the fatty acidsof monogalactosyldiacylglycerol (MGDG) in this species was notgreatly affected by the herbicide whereas its presence significantlyreduced the proportions recovered in 18: 4 and 20: 1 in digalactosyldiacylglycerol(DGDG). The level of 20: 5 (n–3) in DGDG of C. salinawas increased from 4.0 to 19.8% by growing the algae in thepresence of Sandoz 9785. The only notable effect of the herbicideon the synthesis of PUFA in N. oculata was a reduction from18.3% to 11.3% of the proportion of radioactivity recoveredin 20: 5 in phospholipids. The herbicide had no effect on thedistribution of radioactivity in PUFA of galactolipids or onthe fatty acid composition of lipid fractions. The results arediscussed in relation to the potential role of galactolipidsand phospholipids as substrates for desaturations involved inthe formation of long chain PUFA in marine microalgae. Key words: Microalgae, herbicide, fatty acids     

Comparison of Extracellular Polysaccharide Composition, Rhizobitoxine Production, and Hydrogenase Phenotype among Various Strains of Bradyrhizobium japonicum

A survey of 51 strains of Bradyrhizobium japonicum was performedwith respect to the composition of extracellular polysaccharide(EPS), the production of rhizobitoxine and the hydrogenase phenotype.A good correlation was found among these three different characteristics.Thirty-six strains producing an EPS composed of glucose, mannose,galactose, 4-O-methyl galactose and galacturonic acid did notsynthesize rhizobitoxine, whereas 14 strains producing an EPScomposed of rhamnose and 4-O-methyl glucuronic acid were allfound to synthesize rhizobitoxine. Hydrogen-uptake positive(Hup⁺) strains were confined exclusively to the former groupof strains which produced an EPS composed of glucose, mannose,galactose, 4-O-methyl galactose and galacturonic acid. Theseresults suggest that the phenotype with respect to rhizobitoxineproduction and hydrogen uptake is involved in the phylogenyof Bradyrhizobium japonicum as well as in the productivity ofnodulated soybeans. (Received March 24, 1989; Accepted June 16, 1989)     

Fatty Acids in Buckwheat are Growth Inhibitors

Four fatty acids, palmitic, stearic, arachidic and behenic acids,were identified (using gas chromatography-mass spectrometry)from buckwheat seedlings. These fatty acids at a concentrationof 250 ppm caused a slight but significant inhibition in growthof rice seedlings. Fagopyrum cymosum, fatty acid, growth inhibitor     

Positional Distribution of Fatty Acids in Glycerolipids of the Marine Red Alga, Porphyra yezoensis

The positional distribution of fatty acids in glycerolipidsfrom thalli of Porphyra yezoensis was studied by enzymatic hydrolysis.In monogalactosyl diacylglycerol, icosapentaenoic acid was amajor fatty acid at both the sn-1 and sn-2 positions of theglycerol moiety, whereas palmitic acid was a minor componentat both positions. In digalactosyl diacylglycerol and sulfoquinovosyldiacylglycerol, icosapentaenoic and palmitic acids were almostexclusively distributed at the sn-1 and sn-2 positions, respectively.In phosphatidylglycerol, palmitic and trans--13-hexadecenoicacid were exclusively located at the sn-2 position. In phosphatidylcholine,icosapentaenoic acid occurred in both the sn-l and sn-2 positions,whereas palmitic acid was confined to the sn-1 position. Itis suggested that monogalactosyl diacylglycerol in P. yezoensissynthesized in both the cytoplasmic and chloroplastic pathways,while the diacylglycerol moieties of the other chloroplast lipidsare virtually all derived from the chloroplastic pathway. (Received March 7, 1986; Accepted April 6, 1987)     

Lipid biomarkers and trophic linkages between phytoplankton, zooplankton and anchovy (Engraulis encrasicolus) larvae in the NW Mediterranean

Identification and quantification of the main fatty acids inphytoplankton, zooplankton and Engraulis encrasicolus larvaewere used to study the relationship among the different trophiclevels. Three northwestern Mediterranean sea areas were studiedas representative of potentially heterogeneous environments.HPLC pigment analysis was performed to assess the contributionof different phytoplankton groups to total chlorophyll biomass.In spite of the physical variability, a homogeneous patternin phytoplankton composition among areas was found, with thePrymnesiophyceae representing more than half of the phytoplanktonchlorophyll biomass. This homogeneous spatial pattern was alsoreflected in the phytoplankton fatty acid proportions. Thus,significant amount of 14:0, 18:1(n-9) and 18:4(n-3) could berelated to the dominance of the prymnesiophytes; the low proportionof fatty acid markers of diatoms and dinoflagellates agreedwith the low abundances of those phytoplankton groups. Zooplanktonfatty acids also showed homogeneous proportions in the studiedareas, with a preferential accumulation of 16:1(n-7) and 20:5(n-3),and 22:6(n-3). This observation may indicate a preferentialgrazing on diatoms and dinoflagellates. Anchovy larvae displayeddiffering fatty acids contributions related to size. Large larvaecontained a higher proportion of polyunsaturated fatty acid(PUFA). Small larvae showed a high percentage of 18:1(n-9) and18:4(n-3) fatty acids, considered Prymnesiophyceae biomarkers.These results suggest an additional food resource for the anchovythat is complementary to a zooplankton diet, but probably ofprotozoan origin (i.e. microzooplankton). Significant logarithmicrelationships were found between dry mass and 20:5(n-3) and22:6(n-3) fatty acid proportions in E. encrasicolus larvae.These PUFA are considered essential for the fish-larvae development.     

N-Terminal Amino Acid Sequence and Processing Site of Sweet Potato Cytochrome c Oxidase Subunit II

The N-terminal amino acid sequence of sweet potato cytochromec oxidase subunit II polypeptide was determined. Comparisonsbetween the sequence and amino acid sequences deduced from thenucleotide sequences of other higher plant subunit II genesindicate a post-translational clevage of N-terminal extensionpart. ¹Present address: Institute of Low Temperature Science, HokkaidoUniversity, Sapporo, 060 Japan. (Received June 13, 1989; Accepted September 8, 1989)     

Activation of 20S Proteasomes from Spinach Leaves by Fatty Acids

In order to clarify the mechanism of activation of plant 20Sproteasomes by fatty acids, we examined the effects of oleic,linoleic and linolenic acids on the three peptidase activitiesof purified 20S proteasomes from spinach leaves and comparedthem with the effects of SDS, a previously characterized activatorof 20S proteasomes. The three fatty acids all activated thehydrolysis of succinyl-Leu-Leu-Val-Tyr-4-methylcoumaryl-7-amide(Suc-LLVYMCA) and benzyloxycarbonyl-Leu-Leu-Glu-2-naphthylamide(Cbz-LLE-2NA) at low concentrations (one-third to one-sixthof that required for activation by SDS). The range of concentrationsof linolenic acid for the activation of Suc-LLVY-MCA hydrolysiswas very narrow. All the fatty acids inhibited the hydrolysisof tert-butoxycarbonyl-Leu-Arg-Arg-4-methylcoumaryl-7-amide(Boc-LRR-MCA)at extremely low concentrations (one-fifth to one-fifteenthof that required for the activation of the hydrolysis of Suc-LLVY-MCAand Cbz-LLE-2NA). In the case of hydrolysis of Suc-LLVY-MCA,SDS and the three fatty acids increased the V_max value and decreasedthe apparent K_m value to similar relative extents. In the caseof hydrolysis of Boc-LLE-MCA, SDS and the three fatty acidsalso decreased the K_m and increased the V_max. However, SDS markedlyincreased V_max. The curves representing the SDS-dependent activationwere shifted to a lower range by the addition of linoleic acid,but the maximum activity at the optimum concentration of SDSwas essentially unchanged. These results suggest that the activationby SDS and that by the fatty acids has an additive effect. Theresults imply that fatty acids, such as linolenic acid, mightact as physiological regulators in plant cells. (Received April 10, 1995; Accepted December 22, 1995)