Surface lipids of Sphaerotheca fuliginea spores

The major components (50%) of the surface lipid extract of fungal spores (5.6% of dry spore wt) of Sphaerotheca fuliginea are esters of primary alcohols and fatty acids. Esters (15%) of primary alcohols and a Δ^2t acid are present. The major acid moieties of the alkyl esters are C₂₂ and C₂₄ and of the Δ^2t alkyl ester is Δ^2t C₂₂; for both classes eicosanol is the major primary alcohol. The major ester of each class was concluded to be eicosanyl docosanoate and eicosanyl trans-2-docosenoate. Minor components are saturated and Δ^2t methyl and diol diesters and free fatty acids. The major acid moieties of the diol diesters are C₂₂ and C₂₄ and the major diol is 1,12-dodecanediol.     

Analysis of lipids in the salivary glands of Amblyomma americanum (L.): Detection of a high level of arachidonic acid

Analysis of lipids in salivary glands of the lone star tick, Amblyomma americanum, demonstrated that arachidonic acid (20:4, n-6) comprises 8% of all fatty acids identified by gas chromatography. The occurrence of arachidonic acid and other C₂₀ polyunsaturated fatty acids in tick salivary glands was confirmed by gas chromatography-mass spectrometry. Arachidonate is located entirely in the phospholipid fraction and is associated exclusively with phosphatidylcholine (PC) and phosphatidylethanolamine (PE). Salivary glands stored and frozen for several months had a similar lipid composition as freshly dissected salivary glands, with the exception of a small amount of free arachidonic acid and an increase in lysophosphatidylcholine. Incubation of salivary gland homogenates with snake venom phospholipase A₂ showed that most saturated fatty acids are esterified in the sn-1 position of PC and PE, with the unsaturated fatty acids in the sn-2 position. Approximately 75% of arachidonic acid is in the sn-2 position of PC and PE, adding support to the hypothesis that arachidonic acid is released into the cytoplasm after activation of a phospholipase A₂ for subsequent metabolism to prostaglandins and/or other eicosanoids. © 1993 Wiley-Liss, Inc.     

Volatile constituents and fatty acid composition of lipids in Durio zibethinus

The predominating flavour compounds in the fruit pulp of Durio zibethinus were hydrogen sulfide, ethyl hydrodisulfide and several dialkyl polysulfides, particularly (C₂H₅)₂S_n, where n = 2 or 3. Ethyl acetate, 1,1-diethoxyethane and ethyl 2-methylbutanoate contribute to an additional fruity odour note. Hydrodisulfides are probably the precursors of the dialkyl sulfides. In the pericarp and seed no volatile sulfur compounds could be detected. The fatty acid composition of the lipids in pericarp, pulp and seed depended on the origin and/or harvest season of the fruit. The main components were oleic and palmitic acids or arachidic acid together with appreciable quantities of palmitoleic, stearic, linoleic and linolenic acids.     

A new fungal pathogen of the scavenger mite,Tydeus gloveri

A new fungal pathogen, Hirsutella tydeicola, was found causing epizootics in populations of the scavenger mite, Tydeus gloveri, during the summer of 1979 and 1980 on citrus in Florida. The fungus is described in association with its host using light and scanning electron microscopy. H. tydeicola is compared with a closely related species, H. thompsonii, a coexisting pathogen of the citrus rust mite. All attempts to isolate the fungus on various agar media failed.     

Thematic review series: skin lipids. The role of epidermal lipids in cutaneous permeability barrier homeostasis

The permeability barrier is required for terrestrial life and is localized to the stratum corneum, where extracellular lipid membranes inhibit water movement. The lipids that constitute the extracellular matrix have a unique composition and are 50% ceramides, 25% cholesterol, and 15% free fatty acids. Essential fatty acid deficiency results in abnormalities in stratum corneum structure function. The lipids are delivered to the extracellular space by the secretion of lamellar bodies, which contain phospholipids, glucosylceramides, sphingomyelin, cholesterol, and enzymes. In the extracellular space, the lamellar body lipids are metabolized by enzymes to the lipids that form the lamellar membranes. The lipids contained in the lamellar bodies are derived from both epidermal lipid synthesis and extracutaneous sources. Inhibition of cholesterol, fatty acid, ceramide, or glucosylceramide synthesis adversely affects lamellar body formation, thereby impairing barrier homeostasis. Studies have further shown that the elongation and desaturation of fatty acids is also required for barrier homeostasis. The mechanisms that mediate the uptake of extracutaneous lipids by the epidermis are unknown, but keratinocytes express LDL and scavenger receptor class B type 1, fatty acid transport proteins, and CD36. Topical application of physiologic lipids can improve permeability barrier homeostasis and has been useful in the treatment of cutaneous disorders.     

A Temperature Dependence of the Intra- and Extracellular Fatty-Acid Composition of Green Algae and Cyanobacterium

The effect of ambient temperature on the composition of intracellular fatty acids and the release of free fatty acids (FFA) into a medium by cyanobacterium Spirulina platensis and eukaryotic microalgae, Chlorella vulgaris and Botryococcus braunii, was studied using their batch cultures. It was found that all the species studied, regardless of their taxonomic status, responded to the temperature regime by similar changes in their intracellular fatty acid composition: the relative content of more unsaturated fatty acids decreased with the elevation of temperature. At the same time, in the prokaryote, this temperature shift blocked, first of all, the elongation of 16:0 to 18:0 and then their further desaturation. In eukaryotes, the change in the desaturation of dienoic to trienoic fatty acids was the most pronounced process. The ratio of dienoic to trienoic fatty acids remained almost unchanged in S. platensis. The relative content of extracellular unsaturated FFA increased in the prokaryotic organism S. platensis at a higher temperature. But no significant changes in the composition of extracellular unsaturated FFA were detected in eukaryotic algae upon temperature elevation.     

Cerebral perfusion of metabolic inactivators: A new method for rapid fixation of labile lipid pools in brain

This paper describes a new method for the rapid fixation of labile lipid pools in the brain. Perfusion of the brain with 0.9% saline containing esterase inhibitors (p-bromphenacyl-bromide and diisopropyl fluorophosphate), an antioxidant (nordihydroguaiaretic acid) and a Ca²⁺ chelator (EDTA) resulted in a substantial reduction in the levels of free fatty acids, a biochemical marker for the degradation of labile membrane lipids. Levels of unesterified polyunsaturated fatty acids in whole brain were decreased by 90–96% as compared to levels in brains perfused with saline alone. Levels of docosahexaenoic acid approximated levels obtained after microwave irradiation. Unlike microwave irradiation, this perfusion technique perserves the cellular structure of the brain, thereby allowing subcellular fractionation with minimal postmortem changes in lipid pools. The release of arachidonic acid during isolation of the P₂ (synaptosomal) fraction was completely inhibited by the presence of the metabolic inactivators. The results of this study demonstrate a new and useful technique for the postmortem inactivation of enzymes responsible for the degradation of labile lipids in the brain. Further, the data underscore the key role of phospholipase A₂ and Ca²⁺ in mediating the release and accumulation of free fatty acids in the ischemic brain.Abbreviations 204 arachidonic acid - 226 docosahexaenoic acid - 160 palmitic acid - 180 stearic acid - 181 oleic acid - 182 linoleic acid - NDGA nordihydroguaiaretic acid - pBPB p-bromphenacylbromide - EDTA ethylenediamine-tetraacetic acid - DFP diisopropyl fluorophosphate - FFA free fatty acids - TLC thin layer chromatography - GLC gas liquid chromatography     

In Vivo Studies on the Extracellular, and Veratrine-Releasable, Pools of Endogenous Amino Acids in the Rat Striatum: Effects of Corticostriatal Deafferentation and Kainic Acid Lesion

The effects of corticostriatal deafferentation (decortication) and destruction of intrinsic neurons (intrastriatal kainate injection) on the extracellular concentration, and veratrine-releasable pools, of endogenous amino acids in the rat striatum were examined using the in vivo brain dialysis technique. Intracellular amino acid content was also determined. Decortication reduced selectively intra- and extracellular levels of glutamate (Glu) and aspartate (Asp). Extracellular changes were more pronounced than those in tissue content. gamma-Aminobutyric acid (GABA), taurine (Tau), and phosphoethanolamine (PEA) levels were not affected, whereas nonneuroactive amino acids were increased at 1 week but not at 1 month post-lesion. The intracellular pool of Glu and Asp was also reduced in kainate-lesioned striata. However, extracellular levels of these compounds were not affected significantly by this treatment. The tissue content of all other amino acids was decreased, the most prominent change being in the concentration of GABA. Extracellular GABA concentration was also reduced dramatically, whereas the concentrations of noneuroactive amino acids were increased to varying degrees. These data suggest that transmitter pools of neuroactive amino acids are an important supply for their extracellular pools. Lesion-induced alterations in nonneuroactive amino acids are discussed with regard to the loss of metabolic pools, glial reactivity, and changes in blood-brain barrier transport. Veratrine induced a massive release of neuroactive amino acids such as Glu, Asp, GABA, and Tau into the extracellular fluid, and a delayed increase in PEA. Extracellular levels of neuroactive amino acids were raised slightly. Decortication reduced, selectively, the amounts of Glu and Asp released by veratrine.(ABSTRACT TRUNCATED AT 250 WORDS)     

Butyrylcholinesterase in lipid metabolism: A new outlook

Cholinesterase enzymes acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) are traditionally associated with the termination of acetylcholine mediated neural signaling. The fact that these ubiquitous enzymes are also found in tissues not involved in neurotransmission has led to search for alternative functions for these enzymes. Cholinesterases are reported to be involved in many lipid related disease states. Taking into view that lipases and cholinesterases belong to the same enzyme class and by comparing the catalytic sites, we propose a new outlook on the link between BChE and lipid metabolism. The lipogenic substrates of BChE that have recently emerged in contrast to traditional cholinesterase substrates are explained through the hydrolytic capacity of BChE for ghrelin, 4-methyumbelliferyl (4-mu) palmitate, and arachidonoylcholine and through endogenous lipid mediators such as cannabinoids like anandamide and essential fatty acids. The abundance of BChE in brain, intestine, liver, and plasma, tissues with active lipid metabolism, supports the idea that BChE may be involved in lipid hydrolysis. BChE is also regulated by various lipids such as linoleic acid, alpha-linolenic acid or dioctanoylglycerol, whereas AChE is inhibited. The finding that BChE is able to hydrolyze 4-mu palmitate at a pH where lipases are less efficient points to its role as a backup in lipolysis. In diseases such as Alzheimer, in which elevated BChE and impaired lipid levels are observed, the lipolytic activity of BChE might be involved. It is possible to suggest that fatty acids such as 4-mu palmitate, ghrelin, arachidonoylcholine, essential fatty acids, and other related lipid mediators regulate cholinesterases, which could lead to some sort of compensatory mechanism at high lipid concentrations.

     

Disbalance of the natural ratio of cations in water as a factor affecting synthesis of lipids and fatty acids in fish eggs

The effects on the lipid status of developing embryos of a disturbed natural ratio of cations in water as a result of the pollution of water bodies by waste with a high potassium content (130–140 mg/l) were studied in the laboratory. The results obtained confirm the indication of reduced lipid synthesis and altered formation of phospholipids in embryos developing in a medium with a disturbed natural ratio of cations. In addition, the lysophospholipid fraction increased in these embryos, which indicates activation of phospholipid hydrolysis. It was also found that changes in the salt regime lead to a decreased content of cholesterol, the main membrane thickener. It was proposed that the changes discovered lead to disturbed stability and permeability of the membranes of fish eggs, with the subsequent death of embryos.     

Medicinal mushrooms: Valuable biological resources of high exploitation potential

Higher Basidiomycetes and Ascomycetes mushrooms possess various immunological and anticancer properties. They also offer important health benefits and exhibit a broad spectrum of pharmacological activities including antibacterial, antifungal, antiviral, cytotoxic, immunomodulating, anti-inflammatory, antioxidative, antiallergic, antidepressive, antihyperlipidemic, antidiabetic, digestive, hepatoprotective, neuroprotective, nephroprotective, osteoprotective, and hypotensive activities. This minireview summarizes the perspectives, recent advances, and major challenges of medicinal mushrooms with reference to their nutraceutical properties and dietary value, the production of mushroom biomass on various substrates, and the purification, characterization, and pharmaceutical effects of biologically active compounds from medicinal mushrooms.     

Long-chain omega 3 fatty acids: Molecular bases of potential antioxidant actions

Several lines of investigation are being developed to assess the impact of polyunsaturated fatty acids, namely those of the omega 3 series, intake on oxidative stress. Keeping in mind that there might be a dose-response relation, in vivo and in vitro data strongly suggest that omega 3 fatty acids might act as anti- rather than pro-oxidant in several cells such as vascular cells, hence diminishing inflammation, oxidative stress, and, in turn, the risk of atherosclerosis and degenerative disorders such as cardiovascular disease.     

Influence of zooplankton and phytoplankton on the fatty acid composition of digesta and tissue lipids of silver carp: mesocosm experiment

Zooplankton appeared to be the major contributor to the diet of 1+ silver carp, whereas 3+ fishes exhibited a more evenly balanced spectrum between zooplankton and phytoplankton. The fatty acids profiles of digesta were influenced by zooplankton, particularly for 1+ silver carp. Together, fatty acid profiles of tank zooplankton and digesta were characterized by high proportion of 20 : 5ω3 and 20 : 6ω3. The fatty acids composition of the phytoplankton reflected the dominance of cyanobacteria and chlorophycea, with high quantities of 18 : 2ω6 and 18 : 3ω3. Although cyanobacteria accounted for >70% of the phytoplankton biomass ingested by the carp, fatty acids profiles of digesta were not influenced by phytoplankton fatty acids composition. The low digestive and conversion efficiency of Microcystis aeruginosa explain this absence of relation. The neutral lipids in silver carp tissues reflected poorly the fatty acids profiles in the diet, the semi-natural conditions and the diet dominated throughout the study by zooplankton, led to little variation in tissues fatty acids. The phospholipids in the muscle, liver and peri-intestinal fat were characterized by a rather low proportion of polyunsaturated fatty acids (PUFA) in both 1+ and 3+ fish. From a qualitative view point, cryptophycea, diatoms, and especially zooplankton are much more valuable food for the silver carp than cyanobacteria and desmid chlorophycea which are poor in long-chain PUFA.     

Use of lipids for chemotaxonomy of octocorals (Cnidaria: <Emphasis Type="Italic">Alcyonaria</Emphasis>)

The relationship between taxonomic position and the lipid composition of octocorals from coastal waters of Vietnam was investigated. The principal component analysis of the total fatty acid (FA) composition of 64 coral specimens showed that total FAs are markers at the family level. A good distinction was obtained between antipatarians, gorgonians, and alcyonarians. Azooxanthellate corals of the genus Dendronephthya formed a separate group. The alcyonarian genera Sinularia, Lobophytum, and Sarcophyton were distinguished only by the composition of polyunsaturated FAs. The taxon-specific composition of FAs in octocorals is likely to be determined by differences in the nutrition of food sources, symbiont composition, and the enzymatic activity of FA biosynthesis.     

Hexane soluble non-volatiles in flowering to fruiting stages of Fatsia japonica

The n-hexane soluble non-volatile fraction of the acetone extracts from the flower buds, the flowers and the immature and the mature fruits of Fatsia japonica were all found to contain fatty acids, fatty acid methyl esters, squalene, β-amyrin and sterols. At all the stages between budding to the mature fruit, the major fatty acids were palmitic and linoleic acids and the major phytosterol was stigmasterol. In addition steryl and β-amyrenyl esters were found in the flowers and the immature and the mature fruits, but these esters were not present in the flower buds. Sitosteryl ester was the major constituent of the steryl ester fraction in the fruiting stages. Phytol was found in only the flowering stage and triglycerides in only the mature fruits. The variations in the lipid constituents is discussed in relation to the stages from budding to the mature fruit.     

Incorporation of free fatty acids into acylthioesters and lipids of developing sunflower seeds

The synthesis of lipids from radioactive fatty acids in developing sunflower seeds has been examined. Lauric, palmitic, stearic and oleic acids were us