Lipids and sterols of Pinus sylvestris L. sapwood and heartwood

Summary The lipid and sterol content and composition of three lipid fractions (free fatty acids/ sterols, triacylglycerols and sterol/triterpenoid esters) extracted from three stem discs of Pinus sylvestris were assessed to investigate metabolic changes related to heartwood formation. The wood was separated into (1) cambial zone, (2) outer sapwood, (3) inner sapwood, (4) transition zone, (5) outer heartwood and 6) inner heart-wood. The fractions were separated by thin-layer chromatography (TLC) and analysed by gas-liquid chromatography (GLC). The amount of fatty acids of sapwood triacylglycerols was about 1.5% (dry wt.) but a large reduction occurred in the transition zone. In contrast, noticeable amounts of free fatty acids were present only in the heart-wood. The most important fatty acids in the sapwood fractions were 16:0, 18:0, 18:1, 18:2 (the dominant fatty acid in all fractions), 18:3 and 20:3. Together 18:1 and 18:2 formed about 70% of the total triacylglycerol fatty acids. Of the sterol/ triterpenoid esters, 18:2 and 18:3 were predominant. The fatty acid composition of all fractions changed in the transition zone. The sterols found were sitosterol, stigmastanol, campesterol and campestanol. The amount of sterol esters increased towards the heartwood, and the amount of free sterols was lowest in the inner sapwood. Sitosterol was the dominant sterol in both free sterols and sterol esters.     

乌桕桕脂中甾醇和其它成分分离鉴定

通过柱层析、薄层层析等化学方法,从乌桕桕脂中分离得到甾醇及脂肪酸酯类化合物。经气相色谱和气-质联用分析,鉴定出下列化合物:β-谷甾醇、菜油甾醇、Δ~7-豆甾烯醇、肉豆蔻酸甲酯、肉豆蔻酸乙酯、棕榈酸甲酯、硬酯酸甲酯和硬酯酸乙酯。     

Cell-free transfer of sterols from dictyosome-like structures to plasma membrane vesicles of guinea pig testes

Summary Transfer of radiolabeled lipids from dictyosome-like structures (DLS) from testis tubules of the guinea pig as donor to unlabeled plasma membrane from testis tubules immobilized on nitrocellulose as acceptor was studied in a completely cell-free system. As a general label for lipids of the donor DLS, isolated testis tubules were incubated with [¹⁴C]acetate. Time- and temperature-dependent transfer of [¹⁴C]acetate labeled constituents was observed in the cellfree system. However, despite the fact that phospholipids and other constituents were highly labeled in the donor fraction, primarily radioactive sterols were transferred to the plasma membrane acceptor vesicles. Transfer at 37°C represented 0.4 to 0.7% of the total radiolabeled cholesterol at 37°C but little or no transfer occurred at 4°C. The sterols transferred exhibited Chromatographic mobilities corresponding to those of cholesterol and lanosterol. Similar results were obtained with [¹⁴C]mevalonic acid. In subsequent experiments, cholesterol transfer from DLS to plasma membrane was demonstrated by incubation of DLS with [³H]squalene which was converted into sterol or with [¹⁴C]cholesterol. Transfer of sterols required ATP, but not cytosol, and was both time- and temperature-dependent. DLS were more effective than either endoplasmic reticulum or plasma membrane as the donor fraction. The results from the cell-free analysis suggest a possible functional role of the DLS in sterol biogenesis and transfer to the plasma membrane during spermatid development.Abbreviations DLS dictyosome-like structure(s) - PBS phosphatebuffered saline - HEPES 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid - BSA bovine serum albumin     

Hydrogen fluoride effects on plasma membrane composition,ATPase activity and cell structure in needles of eastern white pine (Pinus strobus) seedlings

Eastern white pine (Pinus strobus L.) seedlings were grown in controlled environment growth cabinets and fumigated with 0.4 and 1.6 g m^–3 hydrogen fluoride for 2–28 days. Plasma membranes were isolated from needles of treated and control seedlings and their chemical composition and ATPase activity examined to determine early effects of hydrogen fluoride action. In plants treated for 2 days with both fluoride levels, ratios of plasma membrane free sterols:phospholipids and sterols:proteins were drastically higher than ratios in control plants. Seedlings treated with hydrogen fluoride for 8 days contained plasma membranes with elevated phospholipid:protein and sterol:protein ratios and their plasma membrane ATPase activity was higher than that of control plants. Prolonged, 28-day hydrogen fluoride treatment with 1.6 g m^–3 level was the only treatment which produced a drastic inhibition of plasma membrane ATPase activity. During the initial stages of hydrogen fluoride treatment, treated cells did not show alterations of ultrastructure which were previously shown in cells of plants treated with soil applied sodium fluoride. The results of the present study indicate that the plasma membranes may be among the initial sites of hydrogen fluoride injury to plants as well as initial sites of defense reaction.     

Chemical constituents and biological activities of the soft corals of genus Cladiella: A review

In this review, structures of natural products isolated from the soft corals of genus Cladiella and their biological activities are described.     

Biosorption of sterols from tobacco waste extract using living and dead of newly isolated fungus Aspergillus fumigatus strain LSD-1

ABSTRACT

Sterols are verified to be able to produce polycyclic aromatic hydrocarbons during its pyrolysis. In this study, a kind of Aspergillus fumigatus (LSD-1) was isolated from cigar leaves, and the biosorption effects on the stigmasterol, β-sitosterol, campesterol, cholesterol, and ergosterol by using living and dead biomass of LSD-1 were investigated. The results showed that both living and dead biomass could efficiently remove these sterols in aqueous solution and tobacco waste extract (TWE). Interestingly, compared with the living biomass of LSD-1, the dead biomass of LSD-1 not only kept a high adsorption efficiency but also did not produce ergosterol. Overall, dead biomass of LSD-1 was a more suitable biosorbent to sterols in TWE. Furthermore, Brunner-Emmet-Teller (BET), Fourier transformed infrared spectrometer (FTIR) and scanning electron microscope (SEM) analysis were used to explore the biosorption process of living and dead biomass and their differences, suggesting that the biosorption of sterols was a physical process.     

Chemical components from Sambucus adnata wall

Sambucus adnata Wall. belongs to Caprifoliaceae family. Phytochemical investigation on the aerial parts of S. adnata led to the isolation and identification of 17 known compounds (1–17) including triterpenoids and sterols. Compounds 1 and 8 are isolated from Sambucus adnata for the first time, and it is the first report that compounds 2, 5–6, 9–10, 12–15, and 17 are isolated from the plants of genus Sambucus. Importantly, three types of abundant components: (3β)-urs-12-en-3-yl stearate (0.33 g/kg, ursane type), (3β)-olean-12-en-3-yl stearate (0.17 g/kg, oleanane type), and lupenyl palmitate (0.52 g/kg, lupinane type) could be used as potential chemotaxonomic markers to distinguish among species of Sambucus.     

Steroids,fatty acids and ceramide from the mushroom Stropharia rugosoannulata Farlow apud Murrill

Stropharia rugosoannulata Farlow apud Murrill is an edible mushroom. Phytochemical investigation of the sporophore of Stropharia rugosoannulata resulted in isolation and identification of 16 compounds, including steroids (1-6), steroidal saponins (7), fatty acids (8–10), alkanes (11), ceramides (12), esters (13), pyrimidines (14), vitamins (15) and flavonoids (16). The structure elucidation of isolated compounds was achieved on the basis of NMR and mass spectral data. Compounds 4–16 were isolated for the first time from this genus and their chemotaxonomic significance was discussed. The isolation of steroids (4–5) and ceramides (12) might be used as chemotaxonomic markers for the genus of Stropharia.