Hydrophilic carotenoids: surface properties and aqueous aggregation of a rigid, long-chain, highly unsaturated dianionic bolaamphiphile with a carotenoid spacer

The water dispersibility of astaxanthin was greatly enhanced by converting it to a disodium disuccinate salt. This carotenoid salt behaved as a bolaamphiphile in water; dynamic light scattering (DLS) revealed the formation of stable aggregates with an average hydrodynamic radius close to 1 microm. Larger aggregates were observed in solutions of increased osmolarity. Absorption spectra demonstrated that the aggregates could withstand the addition of 20% acetonitrile before disintegrating to monomers. The physicochemical properties of this astaxanthin derivative in solution were comprehensively studied by measuring surface tension, critical aggregate concentration, surface concentration, molecule area, free energy of adsorption and micellation, adsorption-aggregate energy relationship, and equilibrium constants, and then compared with similar compounds reported previously in the literature.     

Hydrophilic carotenoids: surface properties and aggregation of an astaxanthin-lysine conjugate, a rigid, long-chain, highly unsaturated and highly water-soluble tetracationic bolaamphiphile

The surface and aggregation properties of a synthetic, highly water-soluble carotenoid, the tetracationic astaxanthin-lysine conjugate (Asly), have been examined through measurements of surface tension, optical absorption and dynamic light scattering. The following parameters were determined: critical aggregation concentration c(M), surface concentration Gamma, molecular area a(m), free energy of adsorption and aggregation (DeltaG(ad) degrees and DeltaG(M) degrees , respectively), and the aggregate size r(H). The compound forms true monomolecular solutions in water below c(M); aggregates emerge only at rather high concentrations (> or =2.18 mM).     

Hydrophilic carotenoids: facile syntheses of carotenoid oxime hydrochlorides as long-chain, highly unsaturated cationic (bola)amphiphiles

Stable cationic carotenoid aggregates — predominantly of the J-type — develop when the hydrochlorides of carotenoid aldoximes and ketoximes are exposed to water. The oxime hydrochlorides are obtained by simple syntheses from commercially available food color carotenoids. Bluish-purple, unstable transient compounds were observed during hydrochlorination performed at liquid nitrogen temperature.     

New at-line flow cytometric protocols for determining carotenoid content and cell viability during Rhodosporidium toruloides NCYC 921 batch growth

Rhodosporidium toruloides NCYC 921 batch growth was monitored as a means to evaluate the yeast biomass potential as a source for the production of carotenoids and other lipids.Carotenoid content, cell viability and size were assessed by multiparameter flow cytometry. The saponifiable lipid fraction was assayed by gas–liquid chromatography.The carotenoid production increased during the stationary phase, reaching 78 μg/g while the total fatty acid content attained 32% (w/w) at the end of the fermentation. The fatty acid profile was suitable for biodiesel purposes.As the yeast cells entered the stationary phase, the proportion of cells with depolarised mitochondrial membrane and cells with permeabilised cytoplasmic membrane increased, attaining 65% and 14%, respectively. Nevertheless, a high proportion of cells (82%) showed esterase activity.These results demonstrated that flow cytometry can be a powerful at-line technique to monitor the total carotenoids and cell viability during the yeast growth, being useful for the yeast process optimisation at lab and pilot scales.     

Fatty acid and carotenoid composition ofRhodotorula strains

Lipid content and composition of fatty acids with 6–25 carbon atoms were studied on strains of the 13 pink or red yeast species belonging to the genus Rhodotorula. The total amount of lipid represented an average of 13% of the dry weight. The neutral and polar lipid fractions were analyzed separately. For all the strains studied, the major fatty acids in both fractions were oleic, linoleic and palmitic acids, which formed 80% of the total number of fatty acids. A notable amount of arachidonic acid, a precursor of eicosanoid hormones, was found in R. acheniorum, R. aurantiaca and R. bacarum. Depending on the strain, 1–10 carotenoid pigments were detected; β-carotene was always the major carotenoid present. Received: 13 December 1994 / Accepted: 18 May 1995     

Thin-layer chromatography and high-performance liquid chromatography for the assay of fatty acid compositions of individual phospholipids in platelets from non-insulin-dependent diabetes mellitus patients: effect of eicosapentaenoic acid ethyl ester administration

Eight major phospholipids were separated by a TLC method with a one-dimensional developing system without any pretreatment of the plate and the fatty acids incorporated into each phospholipid class were analysed by an improved HPLC method with a simple elution system, which has advantages with respect to resolution and analysis time. The fatty acid compositions of individual phospholipids in platelets were investigated following administration of ethyl cis-5,8,11,14,17-eicosapentaenoate for more than 13 weeks to patients with non-insulin-dependent diabetes mellitus. The cis-5,8,11,14,17-eicosapentaenoic acid compositions of all phospholipid classes were significantly increased with decreasing platelet aggregation rates after the administration. These results suggested that the present method provides the complete separation of individual phospholipids in sufficient amounts to allow fatty acid analysis on the isolated phospholipid moieties.     

Alterations of the composition and metabolism of pulmonary surfactant phospholipids induced by experimental peritonitis in rats

Pulmonary complications often accompany the development of acute peritonitis. In this study, we analyzed the alterations of alveolar surfactant phospholipids in rats with experimentally induced peritonitis. The results showed a reduction of almost all phospholipid fractions in pulmonary surfactant of experimental animals. The most abundant alveolar phospholipids-phosphatidylcholine and phosphatidylglycerol were reduced significantly in surfactant of rats with experimental peritonitis. In addition, analysis of the fatty acid composition of these two phospholipids revealed marked differences between experimental and control animals. The activity of phospholipase A2, which is localized in the hydrophyllic phase of alveolar surfactant, was higher in rats with experimental peritonitis compared to sham-operated ones. Also, a weak acyl-CoA:lysophospholipid acyltransferase activity was detected in alveolar surfactant of rats with experimental peritonitis, whereas in control animals this activity was not detectable. The lipid-transfer activity was quite similar in pulmonary surfactant of control and experimental rats. The total number of cells and the percentage of neutrophils were strongly increased in broncho-alveolar lavage fluid from rats with peritonitis. Thus, our results showed that the development of peritonitis was accompanied by pulmonary pathophysiological processes that involved alterations of the phospholipid and fatty acid composition of alveolar surfactant. We suggest that the increased populations of inflammatory cells, which basically participate in internalization and secretion of surfactant components, contributed to the observed alterations of alveolar phospholipids. These studies would be useful for clarification of the pathogenic mechanisms underlying the occurrence of pulmonary disorders that accompany acute inflammatory conditions, such as peritonitis and sepsis.     

Fatty Acid Composition of Endoneurium and Perineurium from Adult Rat Sciatic Nerve

Reports on lipid composition of peripheral nervous system have generally been restricted to the saturated fatty acids of the endoneurium. In this work we attempt to determine the fatty acid composition of the different lipid classes in both endo- and perineurium from sciatic nerve microdissection on adult rats. Unsaturated fatty acids were found to make up around 60% of total fatty acids in samples of endoneurium and perineurium, with monounsaturated fatty acids forming 40-50% of total unsaturated fatty acid content. Although the same fatty acids were present in both tissues there was a striking difference in C 18:1 (n-9) and C 18:2 (n-6) ratio between endoneurium and perineurium, which is particularly rich in linoleic acid. The nonpolar perineurial lipids were found to be richest in linoleic acid. Phospholipids were present in the perineurium, and they contained high proportions of saturated and medium-chain monounsaturated fatty acids.     

Regional Studies of Changes in Brain Fatty Acids Following Experimental Ischaemia and Reperfusion in the Gerbil

Regional studies of brain phospholipid metabolism were carried out during a period of ischaemia induced in the gerbil by bilateral carotid occlusion for 60 min. The associated changes in free fatty acids (FFAs) during this period and following recirculation for up to 180 min were noted. Following ischaemia there was a generalised rise in the levels of all FFAs with no selective release of either the unsaturated (arachidonic and docosahexaenoic) or saturated (palmitic and stearic) fatty acids. There were no observed differences between the brain regions studied, which is in contrast to previously reported observations for prostaglandins. There was also no indication of any specific phospholipid fraction being involved in FFA release. This would indicate that the release of FFAs from phospholipids is a nonspecific event, probably due to the action of hydrolytic lipases. Restoration of the circulation resulted in a short, sharp increase (within 5 min) in all FFAs, but in contrast to the observations during ischaemia alone there was a relatively larger rise in the unsaturated FFAs as compared to the saturated FFAs. Following this increase there was a gradual general decline in all FFA levels until 180 min of reperfusion. Since there was no preferential depletion of unsaturated FFAs during reperfusion, when free radical attack is considered to be at its maximum, it is our opinion that free radical peroxidation is unlikely to explain the pathology described in our model.     

Main phospholipids and their fatty acid composition in muscle and cephalothorax of the edible Mediterranean crustacean Palinurus vulgaris (spiny lobster)

The total lipids of muscle and cephalothorax of Mediterranean lobster Palinurus vulgaris were found to be 1.0% and 2.4% of the wet tissue of which the phospholipids represented 66.5% and 47.5%, respectively. The main PhL saturated, monounsaturated and polyunsaturated fatty acids in muscle and cephalothorax were C16:0, C18:0, C18:1ω-9, C18:1ω-7, C20:4ω-6, C20:5ω-3 and C22:6ω-3. 2-OH C14:0 and cyclo-17:0 fatty acids were also identified though in low percentages. The main individual PhL in muscle were found to be phosphatidylcholine (53.5%), 72.0% of which corresponded to the structure of 1,2-diacyl-glycerocholine while the rest 28.0% to 1-O-alkyl-2-acyl-glycerocholine or 1-O-(1-alkenyl)-2-acyl-glycerocholine and phosphatidylethanolamine (19.3%), 75.0% of which corresponded to the structure of 1,2-diacyl-glyceroethanolamine and 25% to 1-O-alkyl-2-acyl-glyceroethanolamine or 1-O-(1-alkenyl)-2-acyl-glyceroethanolamine. Cephalothorax main PhL were found to be PC and PE (66.4% and 18.8%, respectively). In muscle and cephalothorax PC ω-3 fatty acids amounted 7.78% and 8.60%, while in PE amounted 30.77% and 23.65% respectively. Furthermore, in both tissues PhL, cardiolipine phosphatidylserine, phosphatidylinositol, sphingomyelin and lysophosphatidylcholine, were also found.     

Reprint of: Seasonal changes in the composition of storage and membrane lipids in overwintering larvae of the codling moth,Cydia pomonella

The codling moth (Cydia pomonella) is a major insect pest of apples worldwide. It overwinters as a diapausing fifth instar larva. The overwintering is often a critical part of the insect life-cycle in temperate zone. This study brings detailed analysis of seasonal changes in lipid composition and fluidity in overwintering larvae sampled in the field. Fatty acid composition of triacylglycerol (TG) depots in the fat body and relative proportions of phospholipid (PL) molecular species in biological membranes were analyzed. In addition, temperature of melting (T_m) in TG depots was assessed by using differential scanning calorimetry and the conformational order (fluidity) of PL membranes was analyzed by measuring the anisotropy of fluorescence polarization of diphenylhexatriene probe in membrane vesicles. We observed a significant increase of relative proportion of linoleic acid (C18:2n6) at the expense of palmitic acid (C16:0) in TG depots during the larval transition to diapause accompanied with decreasing melting temperature of total lipids, which might increase the accessibility of depot fats for enzymatic breakdown during overwintering. The fluidity of membranes was maintained very high irrespective of developmental mode or seasonally changing acclimation status of larvae. The seasonal changes in PL composition were relatively small. We discuss these results in light of alternative survival strategies of codling moth larvae (supercooling vs. freezing), variability and low predictability of environmental conditions, and other cold tolerance mechanisms such as extending the supercooling capacity and massive accumulation of cryoprotective metabolites.     

Lipid Composition and Temperature Adaptation of the Nervous System of the Leech Hirudo medicinalis L.

The lipid composition of the nervous system of the leech Hirudo medicinalis was investigated following acclimatization of animals at 25 degrees C and 5 degrees C. Choline, ethanolamine, and serine plus inositol phosphoglycerides are the major phospholipid classes of the leech ganglionic chain; minor amounts of lysophosphatidylcholine, phosphatidic acid, and sphingomyelin are also present. Neither the phospholipid pattern nor the cholesterol to total phospholipid molar ratio was dependent on the acclimatization temperature, whereas the fatty acid patterns of choline and serine plus inositol phosphoglycerides were significantly affected. Both for choline and serine plus inositol phosphoglycerides, a significant increase of the unsaturation index and a decrease of saturated to unsaturated fatty acid ratio was observed in animals acclimatized at 5 degrees C in comparison with those acclimatized at 25 degrees C. These observations, which point to increased lipid fluidity of the nervous system of cold-adapted leeches, are strengthened by results obtained by the fluorescence polarization method using 1,6-diphenyl-1,3,5-hexatriene as a probe: a decrease of the fluorescence polarization value was observed throughout the temperature range selected (5-40 degrees C).     

Hydrophobic cell surface and bioflocculation behavior of Rhodococcus erythropolis

An alkane-biodegrading bacterium identified as Rhodococcus erythropolis (NTU-1 strain) was isolated from petroleum contaminated soil. The major purpose of the current research was to study the issues regarding biofloccules formation and cell surface hydrophobicity of NTU-1. When long-chain alkanes are supplied as the carbon source, NTU-1 tends to form biofloccules and remove significant amount of alkanes by biodegradation and physical trapping. Approximately, more than 95% of each alkane could be efficiently removed within 40–68 h. The bioremediation process was accompanied by formation of biofloccules with size ranging from 0.1 to 2 cm in diameter. The MATH test and the hydrophobic slide experiment suggested that NTU-1 might possess a hydrophobic cell surface which is one of the important factors in the formation of biofloccules. It provides the interaction of cells with hydrocarbon droplets effectively and further aggregate into larger clumps. Besides, when grown on n-hexadecane, experimental results revealed that there were at least 11 different growth-associated fatty acids produced, with carbon chain length ranging from 12 to 24, and cell surface hydrophobicity was enhanced via accumulation at the cell surface.     

Antioxidant activity of <Emphasis Type="Italic">Haematococcus pluvialis</Emphasis> cells grown in continuous culture as a function of their carotenoid and fatty acid content

The influence of culture conditions on the quality of Haematococcus pluvialis biomass is assessed. Continuously grown cells have been characterised with respect to their astaxanthin, fatty acid content, and antioxidant activity and compared with those of non-growing haematocysts. Moderate limitation of nitrate availability (1.7 mM) under continuous growth conditions favoured the production of reddish palmelloid cells whose extracts possessed antioxidant activity equivalent to that of haematocyst extracts, despite the lower astaxanthin content (0.6%d.wt.), which is compensated by a higher fatty acid level (7.6%d.wt.). Green cells produced under nitrate saturation conditions (>4.7 mM) exhibit only 40% antioxidant activity than palmelloid. In addition, the major fatty acid present in palmelloid cells was oleic acid (40%f.a.), whereas, in both green cells and haematocysts, the main fatty acids were myristic, palmitic, and oleic acid (20–30%f.a. each). Biomass extracts were fractionated and analysed. The antioxidant capacity was a function of both the carotenoid and the fatty acid profiles, the antioxidant capacity of astaxanthin diesters fraction being 60% higher than astaxanthin monoesters fraction and twice than free astaxanthin. In such a way, the evaluation of the quality of H. pluvialis biomass must take into account both variables. When considering the production of H. pluvialis biomass for human consumption, special attention should be paid to the one-step continuous system approach for the generation of cells rich in both astaxanthin and fatty acids, as they have high antioxidant activity but without thick hard cell wall.     

Methods to reduce background interferences in electron-capture gas chromatographic analysis of valproic acid and its unsaturated metabolites after derivatization with pentafluorobenzyl bromide

Analysis of the branched, medium-chain fatty acid anticonvulsant, valproic acid, and its unsaturated metabolites by gas chromatography with electron-capture detection suffered from background interference caused by the derivatizing reagent pentafluorobenzyl bromide. Background was reduced by keeping the derivatization anhydrous, using an inert solvent, minimizing the amount of pentafluorobenzyl bromide, using hypernucleophilic bases and displacing the derivatization solvent with isooctane. However, these strategies proved difficult to reproduce. Post-derivatization clean-up with HPLC was much more reliable and provided sufficient sensitivity for the analysis of extracts of plasma and brain homogenate. The assay was validated for plasma and brain samples from humans, rats and mice.     

Screening of Malaysian indigenous microalgae for antioxidant properties and nutritional value

Fourteen indigenous microalgal samples from Malaysia were isolated, purified and cultured from fresh, brackish and marine waters. The ability of the microalgae to be natural sources of antioxidants was studied by a screening test using three antioxidant chemical assays [ferric thiocyanate (FTC), thiobarbituric acid (TBA) and 1, 1’-diphenyl-2-picrylhydrazyl (DPPH)]. The results showed that six microalgal methanolic crude extracts (Isochrysis galbana, Chaetoceros calcitrans, Scenedesmus quadricauda, Chlorella vulgaris, Nannochloropsis oculata and Tetraselmis tetrathele) were active in inhibiting the lipid peroxidation of linoleic acid. Among all the microalgae, I. galbana and C. calcitrans showed the highest antioxidant activity (>90%) in FTC and TBA assays, indicating that these microalgae might contain active compounds for protection from lipid peroxidation. Nutritional analyses were performed on microalgae with high antioxidant activities (I. galbana and C. calcitrans) in order to investigate their nutritive value. Both microalgae were found to be rich in nutrients. For examples, I. galbana had average percentage composition of protein, carbohydrate, and lipid, as 47.9 ± 2.5; 26.8 ± 0.2; 14.5 ± 1.4%, respectively, while the corresponding values for C. calcitrans were 36.4 ± 1.7; 27.4 ± 3.0; 15.5 ± 0.9%. In addition, they contained high levels of omega-3 polyunsatrated fatty acids (PUFA) (28.0% ± 0.7 in I. galbana and 28.5% ± 1.4 in C. calcitrans), omega-6 PUFA (6.5% ± 1.8 in I. galbana and 23.0% ± 2.5 in C. calcitrans) and a high composition of essential amino acids. This study illustrates that some microalgae such as I. galbana and C. calcitrans have the potential to be used as natural sources of antioxidants with high nutritional value. Presented at the 6th Meeting of the Asian Pacific Society of Applied Phycology, Manila, Philippines.     

Seasonal changes in the composition of storage and membrane lipids in overwintering larvae of the codling moth,Cydia pomonella

The codling moth (Cydia pomonella) is a major insect pest of apples worldwide. It overwinters as a diapausing fifth instar larva. The overwintering is often a critical part of the insect life-cycle in temperate zone. This study brings detailed analysis of seasonal changes in lipid composition and fluidity in overwintering larvae sampled in the field. Fatty acid composition of triacylglycerol (TG) depots in the fat body and relative proportions of phospholipid (PL) molecular species in biological membranes were analyzed. In addition, temperature of melting (T_m) in TG depots was assessed by using differential scanning calorimetry and the conformational order (fluidity) of PL membranes was analyzed by measuring the anisotropy of fluorescence polarization of diphenylhexatriene probe in membrane vesicles. We observed a significant increase of relative proportion of linoleic acid (C18:2n6) at the expense of palmitic acid (C16:0) in TG depots during the larval transition to diapause accompanied with decreasing melting temperature of total lipids, which might increase the accessibility of depot fats for enzymatic breakdown during overwintering. The fluidity of membranes was maintained very high irrespective of developmental mode or seasonally changing acclimation status of larvae. The seasonal changes in PL composition were relatively small. We discuss these results in light of alternative survival strategies of codling moth larvae (supercooling vs. freezing), variability and low predictability of environmental conditions, and other cold tolerance mechanisms such as extending the supercooling capacity and massive accumulation of cryoprotective metabolites.     

Correlation of chlorophyll a and total carotenoid concentrations with coral bleaching from locations on the Pacific coast of Mexico

Diving campaigns were undertaken to study the bleaching phenomenon in the Mexican Central Pacific and to catalogue the degree to which bleaching affected three coralline reefs (la Boquita, Carrizales, and Tenacatita). Bleaching evaluations of Pocillopora capitata were conducted by assessing the concentrations of chlorophyll a and total carotenoids from samples along submarine transect lines. We identified that the Reffs Boquita and Tenacatita locations were predominantly composed of bleached and pale coral populations. The concentrations of chlorophyll a within the areas of the different populations were greater at sites of greater depth compared with those at the surface. In contrast, the total carotenoid concentrations in normal pigmented coral at greater depth were significantly higher (P?<?0.05) compared with both levels of discolouration at both depths. The chlorophyll a/total carotenoid ratios in these populations are discussed as a potential mechanism responsible for the poor condition of these corals as a result of environmental stress.     

Antioxidant defense of rainbow trout (Oncorhynchus mykiss) in relation to dietary n-3 highly unsaturated fatty acids and vitamin E contents

This study examined the modulation of the antioxidant status and related physiological changes in rainbow trout Oncorhynchus mykiss under different levels of dietary n-3 highly unsaturated fatty acids (n-3 HUFA) and vitamin E. Six diets containing 0, 100 or 1000 mg alpha-tocopheryl acetate kg(-1) diet and 20% or 48% n-3 HUFA provided by normal fish oil or DHA concentrated fish oil, respectively, were fed to 100 g size fish for 15 weeks. Growth of fish fed vitamin E deficient diets under both levels of n-3 HUFA were slightly retarded, accompanied by a reduction of hematocrit values, an enlargement of liver and spleen, an elevation of lipid hydroperoxide in red blood cell and the antioxidant enzymes (superoxide dismutase, catalase, glutathione peroxidase). Supplementation of vitamin E could protect the fish from these adverse effects; however the higher dose was no better compared to the moderate dose. The modulations were clearly seen in fish fed high n-3 HUFA (48%) since they were under greater oxidative stress as indicated by the markers, lipid hydroperoxide and 8-isoprostane. The increased activity of enzymes corresponds to physiological mechanisms combating the elevation of free radicals under oxidative stress and a dietary fatty acid profile-dependent moderate dose of vitamin E is all that is required to function as an effective antioxidant.