Different rhodoxanthin contents in the leaves of gymnosperms grown under various light intensities

The rhodoxanthin content in the leaves of 15 gymnosperm species from sunny and shaded sites was determined. More rhodoxanthin was noted in the leaves of all gymnosperm examined from sunny sites.     

Eco-physiological studies on the response of taxodiaceous conifers to shading,with special reference to the behaviour of leaf pigments

The composition of leaf pigments was studied in 32 species of gymnosperms. In 19 species belonging to four families, both evergreen and deciduous leaves turned to reddish brown in late autumn and winter. The red pigment detected in these leaves proved to be rhodoxanthin. The colouring was due to the disappearance of chloroplast pigments and the subsequent synthesis of rhodoxanthin. Neither qualitative nor quantitative differences were recognised in the chloroplast-derived pigments of green leaves between the species with and without the ability to produce rhodoxanthin. Unlike green leaves in which ca. 10% of total carotenoid content was α-carotene, reddish brown leaves scarcely contained α-carotene. Changes in pigment composition during the reddish colouring of leaves and their regreening were studied in detail and discussed.     

Lipid analysis of Greek walnut oil (Juglans regia L.)

The walnut oil (Juglans regia L.) total lipids (TL) were extracted by the Bligh-Dyer method and the lipid classes have been isolated by chromatographic techniques and they were analyzed by high performance thin layer chromatography (HPTLC)/FID and GC-MS. The oil was found to be rich in neutral lipids (96.9% of total lipids) and low in polar lipids (3.1% of total lipids). The neutral lipid fraction consisted mainly of triacylglycerides whereas the polar lipids mainly consisted of sphingolipids. GC-MS data showed that the main fatty acid was linoleic acid. Unsaturated fatty acids were found as high as 85%, while the percentage of the saturated fatty acids was found 15%. Two types of liposomes were prepared from the isolated walnut oil phospholipids and characterized as new formulations. These formulations may have future applications for encapsulation and delivery of drugs and cosmetic active ingredients.     

Photoprotective role of rhodoxanthin during cold acclimation in Cryptomeria japonica

To examine the role of rhodoxanthin in long‐term acclimation to low temperatures, we monitored seasonal changes in pigment composition, photosynthesis, chlorophyll fluorescence and the level of ribulose‐1,5‐bisphosphate carboxylase/oxygenase (Rubisco) in needles of wild‐type and mutant forms of Cryptomeria japonica. In winter, rhodoxanthin accumulated in sun‐exposed needles of wild‐type plants, but not in those of the mutant. The level of chlorophyll decreased in both types of plant in winter. In contrast, the level of the xanthophyll cycle pool increased in both cases. The level of the pool in the mutant was twice that in the wild type in winter, on a Chl basis, even though the levels in both were similar in summer. The synthesis of rhodoxanthin might be triggered by photo‐inhibitory conditions, as suggested by the sustained elevated levels of zeaxanthin (Z) and antheraxanthin (A). In the wild type and the mutant, the quantum yield of CO₂ fixation (φ), the photosynthetic capacity, the photochemical efficiency of photosystem II (PSII), the photochemical quenching and the level of Rubisco in summer were similar. However, all these values for the wild type were higher than those for the mutant in winter. The non‐photochemical quenching (NPQ) in the mutant in winter increased rapidly even under low light conditions due to the high sustained levels of Z and A. In contrast, in the wild type, the conversion of Z via A to rhodoxanthin prevented the rapid increase in NPQ to maintain the relatively high level of φ. These findings suggest that rhodoxanthin might play an important photoprotective role in long‐term acclimation to cold. The dynamic regulation of the amount of rhodoxanthin relative to the level of the xanthophyll cycle pool might act to maintain an appropriate balance between light absorption, photosynthesis and the thermal dissipation of energy due to excess absorbed light in winter.     

Photosynthetic acclimation to low temperature by western red cedar seedlings

Imposition of low, but above freezing, temperatures resulted in a gradual increase in the cold hardiness of western red cedar seedlings. This was associated with a decrease in the maximum rates of photosynthetic CO₂ fixation and O₂ evolution, and changes in chlorophyll a fluorescence transients which indicated that photoinhibition had occurred. Maximum photosynthetic rates declined approximately 40% during cold hardening. The leaves changed colour from green to red-brown during the hardening process. The colour change was due to the synthesis of large amounts of the carotenoid rhodoxanthin. Lutein levels doubled, while chlorophyll declined slightly. Dehardening resulted in the rapid recovery of photosynthesis to control levels, the rapid disappearance of rhodoxanthin, and the return of lutein levels to control. It is suggested that rhodoxanthin accumulation at low temperature functions to decrease the light intensity reaching the photosynthetic apparatus. The combination of photoinhibition and rhodoxanthin synthesis probably serves to protect the photosynthetic capacity of the seedlings at low temperature.     

Effect of growth temperature on lipid composition of Streptococcus faecium

The effect of growth temperature on the lipid and fatty acid composition of Streptococcus faecium has been studied. No differences in the qualitative composition of S. faecium lipids were observed. In all isolated fractions (neutral lipids, glycolipids, and phospholipids plus other polar lipids), the major fatty acids were palmitic (C-16:0), palmitoleic (C-16:1), octadecenoic (C-18:1), and cyclopropane (C-19:0). Changes in the fatty acid composition of the different fractions were observed which depended on growth temperature; the most significant one was the decrease of octadecenoic acid and the increase of palmitic acid in glycolipids and polar lipids as the temperature increased. The level of cyclopropane C-19:0 was approximately eightfold lower at 8 degrees C than at the other temperatures tested (20, 30, and 45 degrees C).     

Liposomal formulations from phospholipids of Greek almond oil. Properties and biological activity

The seeds of the almond tree [(Prunus dulcis (Mill.) D. A. Webb. (syn. Prunus amygdalus)] were collected in two different periods of maturity and were studied for their lipid content. The total lipids (TL) were extracted by the Bligh-Dyer method and the lipid classes have been isolated by chromatographic techniques and were analyzed by HPTLC coupled with a flame ionization detector (HPTLC/FID) and GC-MS. The oils were found to be rich in neutral lipids (89.9% and 96.3% of total lipids) and low in polar lipids (10.1% and 3.7% of total lipids) for the immature and mature seed oils, respectively. The neutral lipid fraction consisted mainly of triacylglycerides whereas the polar lipids mainly consisted of phospholipids. GC-MS data showed that the main fatty acid for both oils was 9-octadecenoic acid (oleic acid). The unsaturated fatty acids were found as high as 89.4% and 89.7%, while the percentage of the saturated fatty acids was found 10.6% and 10.3% for the immature and mature seed oils, respectively. Liposomes were prepared from the isolated phospholipids using the thin lipid film methodology, and their physical properties were characterized. Cytotoxicity was found absent when assayed against normal and cancerous cell lines. These new formulations may have future applications for encapsulation and delivery of drugs and cosmetically active ingredients.     

Molecular and functional studies of tilapia (Oreochromis mossambicus) NMDA receptor NR1 subunits

The Pin-tailed Manakin (Ilicura militaris) is a small, sexually dimorphic, frugivorous suboscine songbird (Pipridae; Passeriformes; Aves) endemic to the Atlantic Forest of Brazil. A variant individual of this species was recently described in which the red patches that characterise the male's Definitive plumage were replaced by orange-yellow ones. We show here that the pigments in the feathers of the colour variant are common dietary carotenoids (zeaxanthin, beta-cryptoxanthin), not carotenoids synthesised by birds, lending support to the suggestion that the individual is a colour mutant lacking the capability to transform yellow dietary pigments into the red pigments normally present in these feathers. By comparison, the yellow crown feathers of a close relative, the Golden-winged Manakin (Masius chrysopterus), contained predominantly endogenously produced epsilon-caroten-3'-ones. Surprisingly, the normal-coloured feathers of the male Pin-tailed Manakin owe their red hue to rhodoxanthin, an unusual carotenoid more commonly found in plants, rather than 4-keto-carotenoids typically found in red plumages and found lacking in previously characterised bird colour variants. The implication is that birds, like the tilapia fish, may be able to synthesise this unusual pigment endogenously from dietary precursors. A newly described carotenoid, 6-hydroxy-epsilon,epsilon-carotene-3,3'-dione, here named piprixanthin, present in the red feathers of the Pin-tailed Manakin, provides a plausible intermediate between epsilon,epsilon-carotene-3,3'-dione (canary-xanthophyll B), a bright yellow pigment found in this and other songbirds, and rhodoxanthin. It is apparent that pigeons (Columbidae, Columbiformes) also have the capability to produce rhodoxanthin, and a structurally related pigment, endogenously. The ability to synthesise rhodoxanthin might have arisen at least twice in birds.     

Identification, isolation and characterization of tetracosapolyenoic acids in lipids of marine coelenterates.

Several tetracosapolyenoic acids (TPA) were detected in lipids of different marine coelenterates. Two of these acids were isolated and their structures were confirmed by chemical and spectral methods as all-cis-6,9,12,15,18-tetracosapentaenoic and all-cis-6,9,12,15,18,21-tetracosahexaenoic acid. Their distribution among lipids of a number of species of different classes of coelenterates from the northern and tropical seas, among neutral and polar lipids of these organisms was investigated. Significant quantities of TPA were found in all of the Octacorallia species studied. In some cases the sum of TPA reaches the level of 20% of total lipid fatty acids. The fatty acid composition of different coelenterates is also discussed.     

Selective enzymatic radioactive and spin labelling of phospholipids in biological membranes: application to study of temperature-induced changes of microsomal phosphatidylinositols and mitochondrial polyglycerophosphatides.

A new method for the covalent radioactive and spin labelling of lipids within isolated biological membranes has been described in detail and applied to studies of temperature-induced changes of microsomal and mitochondrial membranes. The method is based on the enzymatic use of radioactive substrates carrying covalently bound doxyl derivatives of stearic acid in the biosynthesis of phospholipids in isolated membranes. Radioactive-and spin-labelled lipids bound to the microsomal and mitochondrial membranes were then used as internal probes in monitoring temperature-induced changes of these membranes. Since the analysis of isolated radioactive-and spin-labelled lipids revealed the exact composition of membrane-bound labelled lipids, specific temperature-induced changes were correlated with specific lipids of examined membranes. Phosphatidylinositol of microsomal membranes and polyglycerophosphatides (phosphatidyl-glycerol and cardiolipin) of mitochondrial and inner mitochondrial membranes were found to be involved in the apparent formation of lipid clusters at around 20-30 degrees C. Cardiolipin was found to be involved in the fluidization of inner mitochondrial membranes. These findings are discussed in view of the present state of knowledge of the organization of lipids in biological membranes.     

Chlorosome lipids from Chlorobium tepidum: characterization and quantification of polar lipids and wax esters

We have extracted polar lipids and waxes from isolated chlorosomes from the green sulfur bacterium Chlorobium tepidum and determined the fatty acid composition of each lipid class. Polar lipids amounted to 4.8 mol per 100 mol bacteriochlorophyll in the chlorosomes, while non-polar lipids (waxes) were present at a ratio of 5.9 mol per 100 mol bacteriochlorophyll. Glycolipids constitute 60 % of the polar lipids while phosphatidylglycerol, diphosphatidylglycerol, phosphatidylethanolamine, and an aminoglycosphingolipid make up respectively 15, 3, 8 and 12 %. A novel glycolipid was identified as a rhamnose derivative of monogalactosyldiacylglycerol, while the other major glycolipid was monogalactosyldiacylglycerol. Tetradecanoic acid was the major fatty acid in the aminoglycosphingolipid, while the other polar lipids contained predominantly hexandecanoic acid. The chlorosome waxes are esters of unbranched fatty acids and fatty alcohols with 14 or 16 carbon atoms, joined to form molecules with between 28 and 32 carbon atoms. The stoichiometry between lipids and bacteriochlorophyll suggests that much of the chlorosome surface is covered by protein.     

The role of pigment system of an evergreen dwarf shrub Ephedra monosperma in adaptation to the climate of Central Yakutia

Adaptive reactions of the pigment system in assimilating shoots of evergreen dwarf shrub Ephedra monosperma J.G. Gmel. ex C.A. Mey. were studied under natural conditions of Central Yakutia. Seasonal changes in the content and ratio of green and yellow pigments were revealed; their relation to the stage of plant development and formation of cold tolerance was shown. The decrease in chlorophyll content started in September when the natural photoperiod became shorter and the air temperature lower; the chlorophyll concentration in winter was 30% lower than in summer. The content of β-carotene decreased twofold. The xanthophyll cycle pigments increased in content and deepoxidation level by a factor of 1.7 and 3.6, respectively. In peripheral cells of assimilating parenchyma, accumulation of a secondary carotenoid, rhodoxanthin was noted. In the period of active plant growth (from June to August), rhodoxanthin was absent, while its concentration in shoots in winter was 75 μg/g dry wt. It is concluded that changes in the pigment pool reflect structural and functional reorganization of photosynthetic machinery and are an indispensable part of the intricate process of plant hardening. Activation of energy-dissipating and antioxidant pigment systems, together with accumulation of the light-screening secondary carotenoid rhodoxanthin, promote the retention of photosynthetic apparatus and the survival of Ephedra monosperma plants under extreme conditions of cryolithozone of Yakutia.     

Gel to Liquid-Crystalline Phase Transitions of Lipids and Membranes Isolated from Escherichia coli Cells

Differential scanning calorimetry (DSC) was used to examine the relationship of the gel to liquid-crystalline phase transition of lipids to fatty acid composition with membrane lipids and spheroplast membranes isolated from cells of a wild strain and an unsaturated fatty acid auxotroph of Escherichia coli grown under various conditions. These lipids and membranes underwent thermotropic phase transitions at different temperatures depending on the thermal properties of their constituent fatty acids. The lipid phase transition occurred at higher temperatures in biomembranes than in extracted lipids. DSC thermograms of lipids synthesized by bacterial cells which were observed at a temperature scanning rate as slow as 0.3 K min^-1 were characterized by a distinctly plain peak summit. Endothermic peaks given by samples derived from elaidic acid-enriched cells were relatively narrow and asymmetric. The discrepancy between the transition temperatures measured with extracted lipids and with membraneous fractions, and the shape of the endothermic peaks, are discussed.     

Capnocytophaga spp. contain sulfonolipids that are novel in procaryotes.

A group of unusual sulfonolipids was found in bacteria of the genus Capnocytophaga. One of these lipids, to which we have assigned the trivial name capnine, was isolated in 98% pure form and was identified, by infrared absorption spectrometry, high-resolution mass spectrometry, and other methods, as 2-amino-3-hydroxy-15-methylhexadecane-1-sulfonic acid. Another lipid appears to be an N-acylated version of capnine; after acid hydrolysis, its sulfur was recovered in a form chromatographically indistinguishable from that of capnine. The new lipids are related structurally to sphingosine and the ceramides, respectively, but differ markedly from those compounds in important respects, notably the presence of the sulfonate group. Some Capnocytophaga strains accumulated mostly capnine, whereas others accumulated mostly N-acylcapnine. All seven strains examined were found to contain the new lipids, in amounts ranging from 7 to 16 mumol/g of cells (wet weight). The lipids were found in isolated cell envelopes, where they were present in amounts ranging up to 400 mg/g of envelope protein; they are, accordingly, major cell components.     

Selection of fatty acid auxotrophs from the oleaginous yeast Cryptococcus curvatus and production of cocoa butter equivalents in batch culture

Summary A search was carried out for mutants, defective in the conversion of stearic acid to oleic acid in effort to improve the quality of lipids produced by Cryptococcus curvatus ATCC, 20509. Mutants were selected as unsaturated fatty acid (Ufa) auxotrophs. After treatment of parent organism with Ethyl methanesulfonate (EMS), 11 oleate-requiring auxotrophs were isolated. Only 3 of them were real unsaturated fatty acid (Ufa) mutants, while the other 8 were designated as fatty acid synthetase (Fas) mutants. The amount of saturated fatty acid (SFA) was about 65.2 % in the lipids extracted from an Ufa mutant named UfaM3 and it was significantly higher than that of the wild-type (WT) (46.6 %) and similar to that of cocoa butter (60.4 %).     

Lipids and lipid metabolism in the brown alga, Fucus serratus

The lipids of the brown alga Fucus serratus were isolated, identified and quantified. The major acyl lipids were the three glycosylglycerides, diacylgalactosylglycerol, diacyldigalactosylglycerol and diacylsulphoquinovosylglycerol. These represent over 70% of the total acyl lipids. The fatty acid compositions of the major lipids were examined and most showed rather distinctive fatty acid contents. For example, diacylgalactosylglycerol was enriched in n-3 polyunsaturated fatty acids while phosphatidylcholine and phosphatidylethanolamine had very high levels of arachidonate. Phosphatidylglycerol contained the unusual trans-Δ3-hexadecenoic acid. The labelling of lipids and fatty acids from [¹⁴C]acetate was examined and the distribution of label between individual components as a function of the incubation period and in algae collected at different times of the year is reported. Algae collected in the winter incorporated much more radioactivity into non-esterified fatty acids when compared to algae collected in the summer. All algae could label myristate, palmitate, stearate and oleate at high rates. Longer incubation times allowed the labelling of polyunsaturated fatty acids such as linoleic acid.     

Lipid synthesized by micro‐algae grown in laboratory‐ and industrial‐scale bioreactors

Tetraselmis sp. and Nannochloropsis oculata, cultivated in industrial‐scale bioreactors, produced 2.33 and 2.44% w/w lipid (calculated as the sum of fatty acid methyl esters) in dry biomass, respectively. These lipids contained higher amounts of neutral lipids and glycolipids plus sphingolipids, than phospholipids. Lipids of Tetraselmis sp. were characterized by the presence of eicosapentaenoic acid (that was located mainly in phospholipids), and octadecatetraenoic acid (that was equally distributed among lipid fractions), while these fatty acids were completely absent in N. oculata lipids. Additionally, lipids produced by 16 newly isolated strains from Greek aquatic environments (cultivated in flask reactors) were studied. The highest percentage of lipids was found in Prorocentrum triestinum (3.69% w/w) while the lowest in Prymnesium parvum (0.47% w/w). Several strains produced lipids rich in eicosapentaenoic and docosahexaenoic acids. For instance, docosahexaenoic acid was found in high percentages in lipids of Amphidinium sp. S1, P. parvum, Prorocentrum minimum and P. triestinum, while lipids produced by Asterionella sp. (?) S2 contained eicosapentaenoic acid in high concentration. These lipids, containing ω‐3‐long‐chain polyunsaturated fatty acids, have important applications in the food and pharmaceutical industries and in aquaculture.     

Isomers of rhodoxanthin in reddish brown leaves of gymnosperms and effect of daylight intensity on the contents of pigments during autumnal coloration

The major red carotenoids in autumnal, colored leaves were analyzed in seven species and one variety that belong to two families of gymnosperms. The red carotenoids in leaves of all species and variety were rhodoxanthin, which was separated into three geometric isomers, (6Z, 6′Z)-rhodoxanthin, (6Z)-rhodoxanthin and (all E)-rhodoxanthin. The effects of daylight intensity on the content and composition of the leaf pigments of autumnal coloration were studied with leaves ofCryptomeria japonica (evergreen) andTaxodium distichum (deciduous) grown under different grades of shade. Histological observation showed that many reddish particles of rhodoxanthin were observed inside chromoplasts on the sunny side of a leaf at the early stage of coloration and that the content of the reddish particles was decreased toward the shady side from the sunny side of a leaf. The transition from chloroplasts to chromoplasts was observed and cells at different stage of coloration independently existed in the mesophyll tissue of a leaf. The content of rhodoxanthin became maximum when the daylight intensity was 4.1–7.4 MJ m^?2 day^?1 and the daily mean temp. was below 8.1 C inCryptomeria, and 3.1–8.3 MJ m^?2 day^?1 and 13.4 C inTaxodium.     

Etioplast Development in Dark-grown Leaves of Zea mays L

The ultrastructure of etioplasts and the acyl lipid and the fatty acid composition of sequential 2-centimeter sections cut from the base (youngest) to the top (oldest) of nonilluminated 5-day-old etiolated leaves of Zea mays L., and the acyl lipid and fatty acid composition of the etioplasts isolated from them have been investigated. There is a 2.5-fold increase in the size of the plastids from the base to the tip of the leaf, and an increase both in the size of the prolamellar body and in the length of lamellae attached to it. The etioplasts in the bundle sheath and mesophyll cells of the older, but not the younger leaf tissue, are morphologically distinct. The monogalactosyl and digalactosyldiglycerides, phosphatidylcholine, phosphatidylglycerol, and phosphatidylinositol were the only detectable acyl lipids in the isolated etioplast fractions. Together with phosphatidylethanolamine these were also the major acyl lipids in the whole leaf sections. With increasing age of the leaf tissue, increases occurred in two of the major plastid lipids, monogalactosyldiglyceride and phosphatidylglycerol, while the levels of essentially nonplastid lipids remained constant or declined slightly. The monogalactosyldiglyceride to digalactosyldiglyceride ratio increased from 0.4 to 1.1 in the tissue sections of increasing age and from 0.7 to 1.2 in the etioplasts isolated from them. Similarly, the galactolipid to phospholipid ratio increased from 0.8 to 1.4 in the tissue and from 0.5 to 4.5 in the isolated plastids. In the latter, the proportions of phosphatidylglycerol (as a per cent of total phospholipid) increased from 20 to 41% with increasing age of plastids.

Linolenic acid was the major fatty acid in the total lipid of each of the etioplast fractions, but it was only the major fatty acid in the total lipid of the oldest leaf tissue. Its proportion in both total lipid extracts and individual lipids increased with age. The trans Δ³ hexadecenoic acid was absent from all lipids. The protochlorophyllide content of the tissue increased with age. The results are discussed in relation to the use of illuminated etiolated leaves for studying chloroplast development.

     

Occurrence of gangliosides in the common squid and pacific octopus among protostomia

Acidic lipids from tissues of the common squid Todarodes pacificus and the pacific octopus Octopus vulgaris were characterized. Hepatopancreatic tissues of both animals had complex compositions of resorcinol-positive acidic lipids, many of which became reactive with cholera toxin B subunit and anti-G(M1) antibody after in situ treatment with sialidase on TLC. One of the major acidic lipids in squid tissue was isolated and examined for its structure. This acidic lipid was identified to be the ganglioside G(D1a) based upon the susceptibility to sialidases of different substrate specificity, characterization of reaction products, and electrospray ionization-mass spectrometry of the lipid. Hepatopancreatic tissues of squid and octopus also contained acidic lipids that reacted with A2B5, a monoclonal antibody specific to c-series gangliosides. Cerebral ganglia of both animals expressed resorcinol-positive acidic lipids, though their compositional patterns differed from the hepatopancreatic tissues. N-Acetylneuraminic acid was identified as the main species in lipid-bound sialic acid in both tissues. The contents of lipid-bound sialic acid in cerebral ganglia were significantly lower than those of hepatopancreatic tissues in both animals. The present study presents the first evidence for the occurrence of gangliosides in protostomia.