Lipid and Fatty Acid Composition of the Marine Brown Alga Dictyopteris membranacea

Glycerolipids and fatty acids of D. membranacea (Dic-tyotales)were analysed. The betaine lipid DGTA and the glycolipids MGOG,DGDG and SQDG were major components. The phospholipids PE, PG,PI and PHEG were present in minor amounts only. This lipid pattern,which is characterised by the presence of DGTA and the absenceof PC, has been found exclusively in brown algae belonging tothe orders Dictyotales, Durvillaeales and Fucales. Major fattyacids were 16:0, 18:1, 18:2, 18:3, 18:4 and 20:4 acids. MGDGwas the most unsaturated lipid with high levels of 18:4 acid.SQDG showed the highest degree of saturation containing a considerableproportion of 16:0 acid. DGTA contained 14 : 0,18:1,18:2 and20:4 as major fatty acids. Among phospholipids, PE and PHEGhad a very similar pattern which was enriched in 20:4 acid.Analysis of the positional distribution of fatty acids revealedthat DGTA and MGDG were almost exclusivly of the "euka-ryotic"type, whereas SQDG was predominantly of the "prokaryotic" type.For the first time, molecular species of selected lipids havebeen analysed in a brown alga. In DGTA, 14:0/18:1, 14:0/18:2and 14:0/20:4 were the main molecular species. In MGDG the highlyunsaturated erl8:3/18:4, 18:4/18:4 and 18:4/20:5 were predominant. (Received March 31, 1997; Accepted July 4, 1997)     

Lipid and Fatty Acid Composition in the Flesh of an Edible Marine Fish: Amadi (Coilia reynaldi)

Amadi is a small sized edible marine fish species (Coilia reynaldi) under the order-Clupeiformes. It is important for principal lipids and in particular for highly unsaturated fatty acids which have potential biomedical benefits. Among the lipid classes, phospholipids were found to be the most predominant constituents than the glycolipid and neutral lipid in Amadi. Twenty six fatty acids were quantified by open tube gas–liquid chromatography. Dominant fatty acids in this fish are Palmitic acid (C_16:0), Stearic acid (C_18:0), Oleic acid (C_18:1n?9), Myristic acid (C_14:0), Palmitoleic acid (C_16:1), Docosahexanoic acid (C_22:6n?3), Pentadecanoic acid (C_15:0), and Eicosatetraenoic acid (C_20:4n?3). Fatty acid deficiency in fish species is indicated by the presence of C_20:3n?9 acid. It is absent in this fish.The content of DHA and EPA are maximum in amount in neutral lipid than other lipid classes.     

The Complete Chloroplast and Mitochondrial Genomes of the Green Macroalga Ulva sp. UNA00071828 (Ulvophyceae,Chlorophyta)

Sequencing mitochondrial and chloroplast genomes has become an integral part in understanding the genomic machinery and the phylogenetic histories of green algae. Previously, only three chloroplast genomes (Oltmannsiellopsis viridis, Pseudendoclonium akinetum, and Bryopsis hypnoides) and two mitochondrial genomes (O. viridis and P. akinetum) from the class Ulvophyceae have been published. Here, we present the first chloroplast and mitochondrial genomes from the ecologically and economically important marine, green algal genus Ulva. The chloroplast genome of Ulva sp. was 99,983 bp in a circular-mapping molecule that lacked inverted repeats, and thus far, was the smallest ulvophycean plastid genome. This cpDNA was a highly compact, AT-rich genome that contained a total of 102 identified genes (71 protein-coding genes, 28 tRNA genes, and three ribosomal RNA genes). Additionally, five introns were annotated in four genes: atpA (1), petB (1), psbB (2), and rrl (1). The circular-mapping mitochondrial genome of Ulva sp. was 73,493 bp and follows the expanded pattern also seen in other ulvophyceans and trebouxiophyceans. The Ulva sp. mtDNA contained 29 protein-coding genes, 25 tRNA genes, and two rRNA genes for a total of 56 identifiable genes. Ten introns were annotated in this mtDNA: cox1 (4), atp1 (1), nad3 (1), nad5 (1), and rrs (3). Double-cut-and-join (DCJ) values showed that organellar genomes across Chlorophyta are highly rearranged, in contrast to the highly conserved organellar genomes of the red algae (Rhodophyta). A phylogenomic investigation of 51 plastid protein-coding genes showed that Ulvophyceae is not monophyletic, and also placed Oltmannsiellopsis (Oltmannsiellopsidales) and Tetraselmis (Chlorodendrophyceae) closely to Ulva (Ulvales) and Pseudendoclonium (Ulothrichales).     

Thermal Acclimation of Respiration and Photosynthesis in the Marine Macroalga Gracilaria lemaneiformis (Gracilariales,Rhodophyta)

The responses of respiration and photosynthesis to temperature fluctuations in marine macroalgae have the potential to significantly affect coastal carbon fluxes and sequestration. In this study, the marine red macroalga Gracilaria lemaneiformis was cultured at three different temperatures (12, 19, and 26°C) and at high‐ and low‐nitrogen (N) availability, to investigate the acclimation potential of respiration and photosynthesis to temperature change. Measurements of respiratory and photosynthetic rates were made at five temperatures (7°C–33°C). An instantaneous change in temperature resulted in a change in the rates of respiration and photosynthesis, and the temperature sensitivities (i.e., the Q₁₀ value) for both the metabolic processes were lower in 26°C‐grown algae than 12°C‐ or 19°C‐grown algae. Both respiration and photosynthesis acclimated to long‐term changes in temperature, irrespective of the N availability under which the algae were grown; respiration displayed strong acclimation, whereas photosynthesis only exhibited a partial acclimation response to changing growth temperatures. The ratio of respiration to gross photosynthesis was higher in 12°C‐grown algae, but displayed little difference between the algae grown at 19°C and 26°C. We propose that it is unlikely that respiration in G. lemaneiformis would increase significantly with global warming, although photosynthesis would increase at moderately elevated temperatures.     

Gamone Production in Large-Scale Cultures of Euplotes octocarinatus1

We report a method that allows us to grow and maintain the freshwater ciliate Euplotes octocarinatus in large quantities. Frequent exchange of culture fluid proved more effective than aeration in obtaining high cell densities (4200 cells/ml) and reasonable doubling times in large-scale cultures. For harvesting gamone 1, the cell density was raised to 10,000 cells/ml. Under these conditions, the cells continued to produce and secrete gamone; they were slightly starved, but they no longer divided. Cell-free fluid with a steady and relatively high yield of gamone was obtained from two such cultures over a period of five months. We isolated gamone 1 also from cell homogenates and compared it with secreted gamone 1, but found no differences in the gamones from these two sources.     

Preferential Photosynthetic Uptake of Exogenous HCO(3) in the Marine Macroalga Chondrus crispus

The rate of HCO₃⁻ uptake by the red macroalga Chondrus crispus has been investigated. Unbalanced concentrations of free CO₂ and HCO₃⁻, generated by the photosynthetic activity, were detected in steady state conditions by using an exchange column apparatus linked to an assimilation chamber. Observing the variations of this gradient as influenced by the time of seawater transit from the assimilation chamber towards the column allowed an experimental determination of: (a) the actual gradient created by the photosynthetic activity, (b) the rate constant of the chemical conversion of free CO₂ to HCO₃⁻. With a value of 0.115 per second at pH 8.92, this rate constant was in good agreement with a previous estimation. By using a simple model, we show that the photosynthetic rate of HCO₃⁻ consumption can be estimated by the product of the actual gradient and the rate constant. In the conditions of the experiments reported here, this rate represented more than 90% of the whole photosynthetic flux.     

Variations in Lipid and Fatty Acid Content in Relation to Acetyl CoA Carboxylase in the Marine Prymnesiophyte Isochrysis galbana

Lipid and fatty acid content was determined in Isochrysis galbanacultures grown under various environmental conditions in steadystate continuous cultures. Lipid and fatty acid accumulationwas observed under severe nitrogen limiting conditions. Therate of in situ lipid synthesis, determined from ¹⁴C bicarbonateincorporation into lipid fraction, decreased under nitrogenlimited growth (µ<0.72day^–1), concomitant witha reduction in the in vitro activity of the enzyme acetyl CoAcarboxylase. Cellular lipid and fatty acid content remainedfairly constant over a wide range of irradiance levels. Therate of lipid synthesis, however, increased as irra-diance levelwas elevated to a maximal value at a light intensity of 150µmolquanta m^–2s^–1 and slightly decreased at a higherphoton flux. The in vitro activity of ACCase roughly followedthe same pattern of lipid synthesis in response to light intensity.The relative abundance of acetyl CoA carboxylase significantlydecreased in nitrogen limited cultures grown at low dilutionrates (µ<0.72day^–1). A fairly good linear correlationwas measured between the cellular content of ACCase and theenzyme activity in cultures grown under nitrogen limiting conditions.Furthermore, in nitrogen limited cultures, the cellular fattyacid content was linearly related to the cell capacity to producemalonyl CoA, the end product of ACCase and the building blockin fatty acid synthesis. (Received November 20, 1990; Accepted January 17, 1991)     

Fatty Acid Characterization and Biodiesel Production by the Marine Microalga <Emphasis Type="Italic">Asteromonas gracilis</Emphasis>: Statistical Optimization of Medium for Biomass and Lipid Enhancement

Lipid production is an important indicator for evaluating microalgal species for biodiesel production. In this study, a new green microalga was isolated from a salt lake in Egypt and identified as Asteromonas gracilis. The main parameters such as biomass productivity, lipid content, and lipid productivity were evaluated in A. gracilis, cultivated in nutrient-starved (nitrogen, phosphorous), and salinity stress as a one-factor-at-a-time method. These parameters in general did not vary significantly from the standard nutrient growth media when these factors were utilized separately. Hence, response surface methodology (RSM) was assessed to study the combinatorial effect of different concentrations of the abovementioned factor conditions and to maximize the biomass productivity, lipid content, and lipid productivity of A. gracilis by determining optimal concentrations. RSM optimized media, including 1.36 M NaCl, 1 g/L nitrogen, and 0.0 g/L phosphorus recorded maximum biomass productivity, lipid content, and lipid productivity (40.6 mg/L/day, 39.3%, and 15.9 mg/L/day, respectively) which agreed well with the predicted values (40.1 mg/L/day, 43.6%, and 14.6 mg/L/day, respectively). Fatty acid profile of A. gracilis was composed of C16:0, C16:1, C18:0, C18:3, C18:2, C18:1, and C20:5, and the properties of fuel were also in agreement with international standards. These results suggest that A. gracilis is a promising feedstock for biodiesel production.     

Lipid Fatty Acid Composition and Thermophilicity of Cyanobacteria

An analysis of lipid fatty acid composition in several unicellular and filamentous forms of mesophilic and thermophilic cyanobacteria was performed. At 47°C (the temperature of thermophilic cyanobacteria maintenance in the collection), the unicellular thermophilic Synechococcus strains were devoid of polyenoic acids as distinct from the mesophilic forms of this genus at the temperature of 20°C (the temperature of this cyanobacterial maintenance in the collection). In the thermophilic Synechococcus elongatusIPPAS B-267 strain, a decrease in temperature did not result in the occurrence of C18 polyenoic acids, but the quantitative relationship between the saturated and unsaturated fatty acids (S/U ratio) was decreased twofold. In contrast, the culturing of mesophilic strains at 25–32°C resulted in an increase in the S/U ratio due to an increase in the proportion of the 16:0 acid. In the Synechococcus IPPAS B-434 strain, this treatment resulted in a decrease in the relative content of monoenoic, mainly hexadecenoic, acids. The cyanobacterium Gloeobacter violaceus, which lacks thylakoids, and whose photosystems are formed in a cell membrane, contained polyenoic acids. The filamentous thermophilic cyanobacterium Phormidium laminosum, at the maintenance temperature of 47°C, did contain polyenoic acids, but their proportion was considerably lower than that in the filamentous mesophilic forms, such as Tolypothrix sp. and Spirulina platensis. A relative content of hexadecenoic acids in Ph. laminosum was higher than in the mesophilic forms. A possible role of hexadecenoic acids in the processes of adaptation of cyanobacteria to high temperatures is discussed. A relationship between the characteristics of fatty acid composition fixed by evolution and the changes caused by adaptation to a particular environment is considered.     

Large-Scale Production of Protective Antigen of Bacillus anthracis in Anaerobic Cultures

A production-proving test was described for the preparation, by the anaerobic culture method, of large volumes of culture filtrate containing immunologically potent protective antigen of Bacillus anthracis. The process consisted of the anaerobic culture of a selected production strain in a chemically defined medium. The culture was then clarified and sterilized by filtration through sintered-glass filters. The sterile culture filtrate was adsorbed onto a preformed aluminum hydroxide gel, and the stabilized gel-antigen complex was concentrated. The final product had high immunizing potency, as shown by both in vivo and in vitro assays, and was well tolerated in man. Stability of the product to accelerated aging was good, and storage at 4 C for 1 year caused only a minor loss in protective activity. Large volumes of the highly antigenic gel-adsorbed protective antigen were readily produced by the method described.     

Fatty Acid and Polar Lipid Composition in the Classification of Kurthia

Strains of Kurthia zopfii were degraded by acid methanolysis and the non-hydroxylated fatty acid esters so released were examined by gas liquid chromatography. The major fatty acid types were straight-chain, anteiso - and iso -methyl branched-chain acids. Monounsaturated fatty acids were not detected. The major fatty acid in five of the six strains examined consisted of 12-methyltetra-decanoic ( anteiso -C₁₅) acid. The other strain possessed major amounts of both 13-methyltetradecanoic ( iso -C₁₅) and anteiso -C₁₅ acids. Polar lipids of all the strains were examined by two-dimensional thin-layer chromatography. All possessed a very simple polar lipid composition consisting of diphosphatidylglycerol, phosphatidylglycerol and phosphatidylethanolamine.     

Lipid profiling of the soybean pathogen Phytophthora sojae using Fatty Acid Methyl Esters (FAMEs)

Phytophthora sojae is a destructive soilborne pathogen of soybean, but currently there is no rapid or commercially available testing for its infestation level in soil. For growers, such information would greatly improve their ability to make management decisions to minimize disease damage to soybean crops. Fatty acid profiling of P. sojae holds potential for determining the prevalence of this pathogen in soil. In this study, the Fatty Acid Methyl Ester (FAME) profile of P. sojae was determined in pure culture, and the profile was subsequently evaluated for its potential use in detecting the pathogen in soil. The predominant fatty acids in the FAME profile of P. sojae are the unsaturated 18C fatty acids (18:1ω9 and 18:2ω6) followed by the saturated and unsaturated 16C fatty acids (16:0 and 16:1ω7). FAME analysis of P. sojae zoospores showed two additional long-chain saturated fatty acids (20:0 and 22:0) that were not detected in the mycelium of this organism. Addition of a known number of zoospores of P. sojae to soil demonstrated that fatty acids such as 18:1ω9, 18:2ω6, 20:1ω9, 20:4ω6, and 22:1ω9 could be detected and quantified against the background levels of fatty acids present in soil. These results show the potential for using selected FAMEs of P. sojae as a marker for detecting this pathogen in soybean fields.     

The Ultrastructure of Tetrasporogenesis in the Marine Red Alga Chondria tenuissima (Good, et Woodw.) (Ceramiales, Rhodomelaceae)

Tetraspore development has been studied in Chondria tenuissimausing light and electron microscopy. The transformation of tetrasporangialmother cells into mature tetrasporangia involves a series ofstructural changes, especially of dictyosomes and of the nucleus.The youngest stage of tetrasporogenesis consists of a uninucleatetetraspore mother cell with synaptonemal complexes present duringearly prophase of meiosis I. Mitochondria are aggregated aroundthe nucleus, dictyosome activity is low, and proplastids occurin the peripheral cytoplasm. The cleavage furrows are initiatedalmost concomitantly with commencement of meiosis. When thecleavage furrows are initiated, spherical bodies bounded bytwo membranes are found within the cytoplasm; they develop intovacuoles with fibrillar contents (fv₁), which increase in sizeduring tetraspore development by fusing with each other andwith Golgi vesicles. The Golgi vesicles and the vacuoles withfibrillar contents (fv₁) contribute material to the developingtetraspore wall. During the middle stage of tetraspore formationthe vacuoles with fibrillar contents (fv₁) are dominant, dictyosomeactivity increases, as well as the number of plastids and mitochondria;starch formation also increases. Stacked cisternae of the endoplasmicreticulum are found within the peripheral part of the nucleus.The same nuclear structures are also observed in tetrasporangiaof the marine red alga Gastroclonium clavalum. The final stageis characterized by the disappearance of vacuoles with fibrillarcontents (fv₁) and of the stacked ER within the nucleus, presenceof straight, large dictyosomes which produce cored vesicles,an abundance of starch grains and by the formation of fullydeveloped chlorqplasts. The cored vesicles contain Thiéry-positivematerial and contribute to the formation of vacuoles with fibrouscontents (fv₂) as they are dominant in the tetraspores beforetheir liberation. Rhodophlyla, Chondria, tetrasporogenesis, ultrastructure, Golgi apparatus     

发酵法生产脂肪酸的研究

用毛霉菌做出发菌株 ,经紫外线及硫酸二乙酯等物理化学方法诱变育种 ,筛选出利用葡萄糖生产γ 亚麻酸的菌株 ,并对其发酵条件进行了研究。菌体产率 3 5 %～ 40 % ;脂质含量 2 5 %以上 ,脂质中γ 亚麻酸含量 1 3 %～ 1 4% ,所产脂质脂肪酸组成与天然月见草油基本一致 ,从而解决了天然月见草油资源不足以及γ 亚麻酸含量较低的问题。     

Modeling the Increase and Control of Caulerpa taxifolia, an Invasive Marine Macroalga

Population modeling based on species’ demography makes it possible to predict the pace of an invasion and evaluate the likelihood of success of different control strategies. We modeled the initial (density-independent) rate of increase of Caulerpa taxifolia (Vahl) C. Agardh (aquarium strain), a green alga that has markedly altered marine communities where it has invaded in the Mediterranean Sea. Parameter values for patch growth (from stolon extension) and reproduction (by asexual fragmentation and reattachment) were gleaned from published studies. Only the most conservative model, invoking field growth rates and low levels of fragment reattachment (2.5 m⁻² of existing patch each summer), closely matched observed increases (4–14 × annually). The most effective times for control (greatest reduction in rate of increase) were removal of established patches before summer and removal of fragments after summer. These times correspond to just before maximum growth and just after maximum reproduction, respectively. Only a combined strategy, incorporating 99% removal of all fragments and annual removal of 99% of established patches, was predicted to eliminate C. taxifolia entirely (λ < 1). This level of effort is only likely to be possible during the first few years of an invasion, arguing strongly for careful monitoring and rapid response to potential high-impact invaders.     

Fatty Acid and Polar Lipid Composition in the Classification of Cellulomonas, Oerskovia and Related Taxa

Strains representing the taxa Cellulomonas, Oerskovia, Brevibacterium fermentans, Corynebacterium manihot and Nocardia cellulans were degraded by acid methanolysis and the non-hydroxylated fatty acid esters released examined by thin-layer and gas chromatography. The major fatty acid in all strains was 12-methyltetradecanoic acid ( anteiso C₁₅) which occurred together with other anteiso acids, iso and straight-chain acids. The fatty acid profiles of the cellulomonads were distinguished by the presence of 13-carbon acids and significantly higher proportions of straight-chain acids than found in the other test strains whose profiles were closely similar to one another. Two-dimensional thin-layer chromatography showed that almost identical and very characteristic polar lipid patterns were given by all the organisms under study: the only major components were diphosphatidylglycerol, phosphatidylinositol and two phospho-glycolipids chromatographing similarly to, but distinguishable from, the mono- and diacyl phosphatidylinositol dimannosides characteristic of Nocardia and other actinomycetes. The accumulated lipid data support the reclassification of B. fermentans, Cor. manihot and N. cellulans in the genus Oerskovia.     

Lipid and Fatty Acid Composition of Tree-Growing and Terrestrial Lichens

A comparison of lipid and fatty acid composition was made of the tree-growing lichens Evernia prunastri (L.) Ach., Parmelia saxatilis (L.) Ach. and Hypogymnia physodes (L.) Ach. and the terrestrial species Cetraria islandica (L.) Ach. and Cladonia impexa Harm. In the terrestrial species the total lipid content varied strongly during spring, while the tree-growing species showed much less variation. Phospholipid and sterol content of all lichens was unusually low. Monoglycosyl diglyceride was absent from Parmelia saxatilis. Fatty acids common to higher plants as palmitic, stearic, oleic, linoleic and linolenic acid were invariably present in all lichen species. In addition large quantities of extra-long chain fatty acids like behenic acid, eicosadienoic acid and cyclic aliphatic lichen acids were present in the terrestrial species. The degree of (poly) unsaturation decreased in the order Evernia prunastri, Parmelia saxatilis. Fatty acids common to higher plants as palmitic, stearic, impexa, which decrease was compensated by an increase in extralong chain fatty acids and lichen acids. It is suggested that the lichen acids are of adaptive value for lichen species growing in the terrestrial habitats, which were characterized by extreme diurnal temperature variations. Just as the polyunsaturated fatty acids, lichen acids guarantee at lower temperatures a high flexibility of the membranes involved, at the same time as they are less susceptible to photo-oxidation at the high daytime temperatures.     

Marine green algae (Chlorophyta) from the north coast of Papua New Guinea

The marine benthic green algae of the north coast of Papua New Guinea (mainly from Madang province) are documented, based on collections made by the first author between 1980 and 1990. All records (118 taxa) are listed with bibliographic, taxonomic, nomenclatural and biogeographical notes. Identification keys are added for genera represented by at least two species. Representatives of the Pseudocodiaceae and some Udoteaceae are illustrated. The green algal flora of the north coast appears to be much richer than that of the south coast where 72 taxa, including 19 unchecked records from literature, are recorded from the Port Moresby area.     

Maternal Obesity Reduces Milk Lipid Production in Lactating Mice by Inhibiting Acetyl-CoA Carboxylase and Impairing Fatty Acid Synthesis

Maternal metabolic and nutrient trafficking adaptations to lactation differ among lean and obese mice fed a high fat (HF) diet. Obesity is thought to impair milk lipid production, in part, by decreasing trafficking of dietary and de novo synthesized lipids to the mammary gland. Here, we report that de novo lipogenesis regulatory mechanisms are disrupted in mammary glands of lactating HF-fed obese (HF-Ob) mice. HF feeding decreased the total levels of acetyl-CoA carboxylase-1 (ACC), and this effect was exacerbated in obese mice. The relative levels of phosphorylated (inactive) ACC, were elevated in the epithelium, and decreased in the adipose stroma, of mammary tissue from HF-Ob mice compared to those of HF-fed lean (HF-Ln) mice. Mammary gland levels of AMP-activated protein kinase (AMPK), which catalyzes formation of inactive ACC, were also selectively elevated in mammary glands of HF-Ob relative to HF-Ln dams or to low fat fed dams. These responses correlated with evidence of increased lipid retention in mammary adipose, and decreased lipid levels in mammary epithelial cells, of HF-Ob dams. Collectively, our data suggests that maternal obesity impairs milk lipid production, in part, by disrupting the balance of de novo lipid synthesis in the epithelial and adipose stromal compartments of mammary tissue through processes that appear to be related to increased mammary gland AMPK activity, ACC inhibition, and decreased fatty acid synthesis.