757 resultados para Unsaturated fatty acids


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A study was carried out with three replicates to determine the effects of feeding Moina micrura enriched with astaxanthin alone (M1) or astaxanthin in combination with either vitamin E (M2), vitamin D (M3) or Cod Liver oil (M4) on the growth, survival and fatty acid composition of giant fresh water prawn Macrobrachium rosenbergii (de Man) larvae. Growth rate was expressed as the time taken to the settlement of 95% post larvae. Maximum growth, the lowest time taken to the 95% PL settlement (38.5±0.50 days), was observed in larvae fed with M3 Moina. The highest survival rate (66.0±1.00%) was observed in those fed with M4 Moina and the second highest survival (61.0±1.00%) and growth rates (40.0±0.00 days) were shown with M2 Moina. The minimum values for both growth (42.5±0.50 days) and survival (33.0±1.50%) were observed in the group fed un-enriched Moina. Results also showed that the survival of prawn larvae increased as the quantities of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) increased in the dietary Moina. The highest levels of EPA (5.57±0.21%), DHA (3.50±0.21%) and highest total Highly Unsaturated Fatty Acids (HUFA) (13.87±0.68%) were seen in the Moina fed on astaxanthin and Cod Liver Oil (CLO). The results of the study showed that the nutritive quality of Moina, with respect to important fatty acids, can be increased by enrichment and will influence the growth, survival and the fatty acid composition of fresh water prawn larvae fed on them.

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The present study aimed to evaluate the effect of dietary linolenic acid (LNA)linoleic acid (LA) ratio on growth performance, hepatic fatty acid profile and intermediary metabolism of juvenile yellow catfish Pelteobagrus fulvidraco. Six isonitrogenous and isolipidic diets were formulated to contain incremental levels of LNA from 0 to 5% at the expense of corn oil (rich in LA), resulting in six dietary treatments with LNA to LA ratios ranging from 0.35 to 14.64. The experiment continued for 7 weeks. Best growth and feed intake were obtained in the fish fed the diets containing the LNA/LA ratios of 1.17 and 2.12 (P<0.05). In contrast, feed conversion ratio was the lowest for fish fed the diets containing the LNA/LA ratios of 1.17 and 2.12 (P<0.05). Dietary LNA to LA ratios significantly influenced viscerosomatic index and hepatosomatic index (P<0.05), but not condition factor (P>0.05). Body composition was also significantly influenced by dietary LNA to LA ratios (P<0.05). Generally, liver FA compositions reflected dietary FA profiles. Declining LA and increasing LNA contents in liver were observed with the increasing dietary LNA/LA ratios (P<0.05). Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) increased with the increasing LNA to LA ratios, suggesting that yellow catfish could elongate and desaturate C18 polyunsaturated fatty acids into highly unsaturated fatty acids. As a consequence, the n-6 fatty acids (FA) declined, and total n-3 FA and n-3/n-6 ratios increased with the dietary ratios of LNA/LA (P<0.05). Dietary LNA to LA ratios significantly influenced several enzymatic activities involved in liver intermediary metabolism (P<0.05), such as lipoprotein lipase, hepatic lipase, pyruvate kinase, succinate dehydrogenase, malic dehydrogenase and lactate dehydrogenase, suggesting that dietary LNA/LA ratios had significant effects on nutrient metabolism in the liver. To our knowledge this is the first demonstration of the effects of dietary LNA to LA ratios on the enzymatic activities of liver in fish, which provides information on diet quality and utilization, and can also be used as an indicator of the nutritional status of this fish. (C) 2009 Elsevier B.V. All rights reserved.

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Fatty acid desaturases are enzymes that introduce double bonds into the hydrocarbon chains of fatty acids. The fatty acid desaturases from 37 cyanobacterial genomes were identified and classified based upon their conserved histidine-rich motifs and phylogenetic analysis, which help to determine the amounts and distributions of desaturases in cyanobacterial species. The filamentous or N-2-fixing cyanobacteria usually possess more types of fatty acid desaturases than that of unicellular species. The pathway of acyl-lipid desaturation for unicellular marine cyanobacteria Synechococcus and Prochlorococcus differs from that of other cyanobacteria, indicating different phylogenetic histories of the two genera from other cyanobacteria isolated from freshwater, soil, or symbiont. Strain Gloeobacter violaceus PCC 7421 was isolated from calcareous rock and lacks thylakoid membranes. The types and amounts of desaturases of this strain are distinct to those of other cyanobacteria, reflecting the earliest divergence of it from the cyanobacterial line. Three thermophilic unicellular strains, Thermosynechococcus elongatus BP-1 and two Synechococcus Yellowstone species, lack highly unsaturated fatty acids in lipids and contain only one Delta 9 desaturase in contrast with mesophilic strains, which is probably due to their thermic habitats. Thus, the amounts and types of fatty acid desaturases are various among different cyanobacterial species, which may result from the adaption to environments in evolution. Copyright (c) 2008 Xiaoyuan Chi et al.

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The psychrotrophic Antarctic alga, Chlorella vulgaris NJ-7, grows under an extreme environment of low temperature and high salinity. In an effort to better understand the correlation between fatty acid metabolism and acclimation to Antarctic environment, we analyzed its fatty acid compositions. An extremely high amount of Delta(12) unsaturated fatty acids was identified which prompted us to speculate about the involvement of Delta(12) fatty acid desaturase in the process of acclimation. A full-length cDNA sequence, designated CvFAD2, was isolated from C. vulgaris NJ-7 via reverse transcription polymerase chain reaction (RT-PCR) and RACE methods. Sequence alignment and phylogenetic analysis showed that the gene was homologous to known microsomal Delta(12)-FADs with the conserved histidine motifs. Heterologous expression in yeast was used to confirm the regioselectivity and the function of CvFAD2. Linoleic acid (18:2), normally not present in wild-type yeast cells, was detected in transformants of CvFAD2. The induction of CvFAD2 at an mRNA level under cold stress and high salinity is detected by real-time PCR. The results showed that both temperature and salinity motivated the upregulation of CvFAD2 expression. The accumulation of CvFAD2 increased 2.2-fold at 15A degrees C and 3.9-fold at 4A degrees C compared to the alga at 25A degrees C. Meanwhile a 1.7- and 8.5-fold increase at 3 and 6% NaCl was detected. These data suggest that CvFAD2 is the enzyme responsible for the Delta(12) fatty acids desaturation involved in the adaption to cold and high salinity for Antarctic C. vugaris NJ-7.

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The biosynthesis of glycolipids in E. fasciculatus was studied by C-14 label and chase. The fatty acids in sulphoquinovosyl diacylglycerol (SQDG) were almost 16-carbon and 18-carbon ones. In addition to the two fatty acids, monogalactosyl diacylglycerol (MGDG) and digalactosyl diacylglycerol (DGDG) contained 8.5 mol% and 31.0 mol% of eicosapentaenoic acid (20 : 5), respectively, and this fatty acid was usually distributed in the sn-1 position of the glycerol backbone. When plants were incubated with [2-C-14] acetate, differences existed in the positional distribution of the labeled fatty acids in sn-1 and sn-2 among the three glycerolipids. In SQDG C-14-labeled fatty acids were distributed uniformly in the sn-1 and sn-2 positions. In DGDG, C-14-labeled fatty acids were mainly distributed in the sn-2 position. In MGDG, the radioactivity of fatty acids in sn-1 position was far greater than that in sn-2 position after a 30 min pulse label, and the difference in radioactivity between the two positions decreased rapidly. The above results indicated that differences in the positional distribution of C-14-labeled fatty acids between sn-1 and sn-2 positions might be related to 20 : 5 and the biosynthesis of DGDG. Our results also suggested that E. fasciculatus had the same DGDG biosynthetic pathway as that in higher plants and galactosyl transferase was selective for MGDC.

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Sinking particulate material collected from Nansha Yongshu reef lagoon and the continental shelf of the East China Sea by sediment traps has been analyzed and studied for the first time using organic geochemical method. The results show that about half of the sinking particulate organic matter in the two study areas are consumed before reaching the depth of 5 m to the sea floor and the degree of this consumption in Yongshu reef lagoon is larger than that in the continental shelf of the East China Sea. The distributions of hydrocarbons and fatty acids indicate that the minor difference of biological sources of sinking particulate organic matter exists between Yongshu reel lagoon and the continental shelf of the East China Sea, but they mainly come from marine plankton. Stronger biological and biochemical transformations of sinking particulate organic matter are also observed and the intensity of this transformation in Yongshu reef lagoon is greater than that in the continental shelf of the East China Sea. It is found that the occurrence of C-25 highly branched isoprenoid (HBI) diene may be related to the composition of diatom species.

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The fatty acid compositions of 22 species of marine macrophytes, belonging to the Ceramiales, Cryptonemiales, Nemalionales, Laminariales, Chordariales, Scytosiphonales, Desmarestiales, Dictyosiphonales, Fucales, Dictyotales and Ulvales and collected from the Bohai Sea, were determined by capillary gas chromatography. The contents of polyunsaturated fatty acids (FAs) in the Bohai Sea algae, in comparison with the same species from the Yellow Sea were found to be lower. Red algae had relatively high levels of the acids 16:0, 18:1(n-7), 18:1(n-9), 20:5(n-3) and 20:4(n-6), and those examined were rich in C-20 PUFAs, these chiefly being arachidonic and eicosapentaenoic acids. The major FAs encountered in the Phaeophyta were 14:0, 16:0, 18:1(n-9), 18:2(n-6), 18:3(n-3), 18:4(n-3), 20:4(n-6) and 20:5(n-3). C18PUFAs are of greater abundance in the brown algae than in the red algae examined. All three green algae from the Ulvales had similar fatty acid patterns with major components, 16:0, 16:4(n-3), 18:1(n-7), 18:2(n-6), 18:3(n-3), and 18:4(n-3). They contained 16:3(n-3) and more 16:4(n-3), were rich in C18PUFAs, chiefly 18:3(n-3) and 18:4(n-3) and had 18:1(n-7)/18:1 (n-9) ratios higher than 1. (C) 2002 Elsevier Science Ltd. All rights reserved.

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The seed oil from Nitraria tangutorum samples was obtained by supercritical carbon dioxide extraction methods. The extraction parameters for this methodology, including pressure, temperature, particle size and extraction time, were optimized. The free fatty acids in the seed oil were separated with a pre-column derivation method and 1,2-benzo-3,4-dihydrocarbazole-9-ethyl-p-toluenesulfonate (BDETS) as a labeling regent, followed by high-performance liquid chromatography (HPLC) with fluorescence detection. The target compounds were identified by mass spectrometry with atmospheric pressure chemical ionization (APCI in positive-ion mode). HPLC analysis shows that the main compositions of the seed oil samples were free fatty acids (FFAs) in high to low concentrations as follows: linoleic acid, oleic acid, hexadecanoic acid and octadecanoic acid. The assay detection limits (at signal-to-noise of 3:1) were 3.378-6.572 nmol/L. Excellent linear responses were observed, with correlation coefficients greater than 0.999. The facile BDETS derivatization coupled with mass spectrometry detection allowed the development of a highly sensitive method for analyzing free fatty acids in seed oil by supercritical CO2 extraction. The established method is highly efficient for seed oil extraction and extremely sensitive for fatty acid profile determination. (C) 2007 Elsevier B.V. All rights reserved.

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A method for the determination of long and short chain free fatty acids (FFAs), using 1-[2-(ptoluenesulfonate)-ethyll-2-phenylimidazole-[4,5-f-9,10-phenanthrene (TSPP) as labeling reagent, has been developed. Identification of FFA derivatives was carried out by HPLC-MS with atmospheric pressure chemical ionization (APCI) in positive ion mode. Gradient elution on an Agilent Eclipse XDB-C-8 column gave good separation of the derivatives. Excellent linear responses were observed and good compositional data could be obtained from as little as 200 mg of bryophyte plants and soil samples. Facile TSPP derivatization coupled with HPLC-APCI-MS analysis allowed the development of a highly sensitive method for the quantitative analysis of trace level of FFAs from biological and natural environmental samples.

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A sensitive method for the determination of 30 kinds of free fatty acids (FFAs, C-1-C-30) with 1-[2-(p-toluenesulfonate)-ethyl]-2-phenylimidazole-[4,5-f] 9,10-phenan- threne (TSPP) as labeling reagent and using high performance liquid chromatography with fluorescence detection and identification by online postcolumn mass spectrometry with atmospheric pressure chemical ionization (APCI) source in positive-ion mode (HPLC/MS/APCI) has been developed. TSPP could easily and quickly label FFAs in the presence of K2CO3 catalyst at 90 degrees C for 30 min in N,N-dimethylformamide (DMF) solvent, and maximal labeling yields close to 100% were observed with a 5-fold excess of molar reagent. Derivatives were stable enough to be efficiently analyzed by high performance liquid chromatography. TSPP was introduced into fatty acid molecules and effectively augmented MS ionization of fatty acid derivatives and led to regular MS and MS/MS information. The collision induced cleavage of protonated molecular ions formed specific fragment ions at m/z [MH](+)(molecular ion), m/z [M'+CH2CH2](+)(M' was molecular mass of the corresponding FFA) and m/z 295.0 (the, mass of protonated molecular core structure of TSPP). Fatty acid derivatives were separated on a reversed-phase Eclipse XDB-C-8 column (4.6 x 150 mm, 5 mu m, Agilent) with a good baseline resolution in combination with a gradient elution. Linear ranges of 30 FFAs are 2.441 x 10(-3) to 20 mu mol/L, detection limits are 3.24 similar to 36.97 fmol (injection volume 10 mu L, at a signal-to-noise ratio of 3, S/N 3:1). The mean interday precision ranged from 93.4 to 106.2% with the largest mean coefficients of variation (R.S.D.) < 7,5%. The mean intraday precision for all standards was < 6.4% of the expected concentration. Excellent linear responses were observed with correlation coefficients of > 0.9991. Good compositional data could be obtained from the analysis of extracted fatty acids from as little as 200 mg of bryophyte plant samples.Therefore, the facile TSPP derivatization coupled with HPLC/MS/APCI analysis allowed the development of a highly sensitive method for the quantitation of trace levels of short and long chain fatty acids from biological and natural environmental samples.

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A sensitive method for the determination of long-chain fatty acids (LCFAs) (>C20) using 1-[2-(p-toluenesulfonate)-ethyl]-2-phenylimidazole-[4.5-f]-9,10-phenanthrene (TSPP) as tagging reagent with fluorescence detection and identification with post-column APCI/MS has been developed. The LCFAs in bryophyte plant samples were obtained based on distillation extraction with 1: 1 (v/v) chloroform/methanol as extracting solvent. TSPP could easily and quickly label LCFAs at 90 degrees C in the presence of K2CO3 catalyst in DMF. Eleven free LCFAs from the extracts of bryophyte plants were sensitively determined. Maximal labeling yields close to 100% were observed with a five-fold excess of molar reagent. Separation of the derivatized fatty acids exhibited a good baseline resolution in combination with a gradient elution on a reversed-phase Eclipse XDB-C-8 column. Calculated detection limits from 1.0 pmol injection, at a signal-to-noise ratio of 3, were 26.19-76.67 fmol. Excellent linear responses were observed with coefficients of >0.9996. Good compositional data were obtained from the analysis of the extracted LCFAs containing as little as 0.2 g of bryophyte plant samples. Therefore, the facile TSPP derivatization coupled with HPLC/APCI/MS analysis allowed the development of a highly sensitive method for the quantitation of trace levels of LCFAs from biological and natural environmental samples. (c) 2006 Elsevier B.V. All rights reserved.

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A simple and sensitive high-performance liquid chromatographic (HPLC) method with fluorescence detection and mass spectrometric identification has been developed for analysis of 30 long-chain and short-chain free Fatty acids (FFAs). The fatty acids were derivatized to their esters with 1-[2-(p-toluenesulfonate)ethyl]-2-phenylimidazole-[4,5-f]-9,10-phenanthrene (TSPP) in N,N-dimethylformamide (DMF) at 90 degrees C with anhydrous K2CO3 as catalyst. A mixture Of C-1-C-30 fatty acids was completely separated within 60 min by gradient elution on a reversed-phase C-8 column. Qualitative identification of the acids was performed by atmospheric-pressure chemical ionization mass spectrometry (APCI-MS) in positive-ion mode. The fluorescence excitation and emission wavelengths were 260 and 380 nm, respectively. Quantitative determination of the 30 acids in two Tibetan medicines Gentiana straminea and G. dahurica was performed. The results indicated that the medicines contained many FFAs. Linear correlation coefficients for the FFA derivatives were > 0.9991. Relative standard deviations (RSDs, n = 6) for the fatty acid derivatives were < 3%. Detection limits (at a signal-to-noise ratio of 3:1) were 3.1-38 fmol. When the fatty acid derivatives were determined in the two real samples results were satisfactory and the sensitivity and reproducibility of the method were good.